1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987, 88, 92-98, 1999 Free Software Foundation, Inc.
4 This file is part of GNU CC.
6 GNU CC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GNU CC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU CC; see the file COPYING. If not, write to
18 the Free Software Foundation, 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
21 /*@@ This file should be rewritten to use an arbitrary precision
22 @@ representation for "struct tree_int_cst" and "struct tree_real_cst".
23 @@ Perhaps the routines could also be used for bc/dc, and made a lib.
24 @@ The routines that translate from the ap rep should
25 @@ warn if precision et. al. is lost.
26 @@ This would also make life easier when this technology is used
27 @@ for cross-compilers. */
30 /* The entry points in this file are fold, size_int_wide, size_binop
33 fold takes a tree as argument and returns a simplified tree.
35 size_binop takes a tree code for an arithmetic operation
36 and two operands that are trees, and produces a tree for the
37 result, assuming the type comes from `sizetype'.
39 size_int takes an integer value, and creates a tree constant
40 with type from `sizetype'.
42 force_fit_type takes a constant and prior overflow indicator, and
43 forces the value to fit the type. It returns an overflow indicator. */
55 static void encode PROTO((HOST_WIDE_INT *,
56 HOST_WIDE_INT, HOST_WIDE_INT));
57 static void decode PROTO((HOST_WIDE_INT *,
58 HOST_WIDE_INT *, HOST_WIDE_INT *));
59 int div_and_round_double PROTO((enum tree_code, int, HOST_WIDE_INT,
60 HOST_WIDE_INT, HOST_WIDE_INT,
61 HOST_WIDE_INT, HOST_WIDE_INT *,
62 HOST_WIDE_INT *, HOST_WIDE_INT *,
64 static int split_tree PROTO((tree, enum tree_code, tree *,
66 static tree int_const_binop PROTO((enum tree_code, tree, tree, int, int));
67 static tree const_binop PROTO((enum tree_code, tree, tree, int));
68 static tree fold_convert PROTO((tree, tree));
69 static enum tree_code invert_tree_comparison PROTO((enum tree_code));
70 static enum tree_code swap_tree_comparison PROTO((enum tree_code));
71 static int truth_value_p PROTO((enum tree_code));
72 static int operand_equal_for_comparison_p PROTO((tree, tree, tree));
73 static int twoval_comparison_p PROTO((tree, tree *, tree *, int *));
74 static tree eval_subst PROTO((tree, tree, tree, tree, tree));
75 static tree omit_one_operand PROTO((tree, tree, tree));
76 static tree pedantic_omit_one_operand PROTO((tree, tree, tree));
77 static tree distribute_bit_expr PROTO((enum tree_code, tree, tree, tree));
78 static tree make_bit_field_ref PROTO((tree, tree, int, int, int));
79 static tree optimize_bit_field_compare PROTO((enum tree_code, tree,
81 static tree decode_field_reference PROTO((tree, int *, int *,
82 enum machine_mode *, int *,
83 int *, tree *, tree *));
84 static int all_ones_mask_p PROTO((tree, int));
85 static int simple_operand_p PROTO((tree));
86 static tree range_binop PROTO((enum tree_code, tree, tree, int,
88 static tree make_range PROTO((tree, int *, tree *, tree *));
89 static tree build_range_check PROTO((tree, tree, int, tree, tree));
90 static int merge_ranges PROTO((int *, tree *, tree *, int, tree, tree,
92 static tree fold_range_test PROTO((tree));
93 static tree unextend PROTO((tree, int, int, tree));
94 static tree fold_truthop PROTO((enum tree_code, tree, tree, tree));
95 static tree strip_compound_expr PROTO((tree, tree));
96 static int multiple_of_p PROTO((tree, tree, tree));
97 static tree constant_boolean_node PROTO((int, tree));
98 static int count_cond PROTO((tree, int));
99 static void const_binop_1 PROTO((PTR));
100 static void fold_convert_1 PROTO((PTR));
103 #define BRANCH_COST 1
106 /* Suppose A1 + B1 = SUM1, using 2's complement arithmetic ignoring overflow.
107 Suppose A, B and SUM have the same respective signs as A1, B1, and SUM1.
108 Then this yields nonzero if overflow occurred during the addition.
109 Overflow occurs if A and B have the same sign, but A and SUM differ in sign.
110 Use `^' to test whether signs differ, and `< 0' to isolate the sign. */
111 #define overflow_sum_sign(a, b, sum) ((~((a) ^ (b)) & ((a) ^ (sum))) < 0)
113 /* To do constant folding on INTEGER_CST nodes requires two-word arithmetic.
114 We do that by representing the two-word integer in 4 words, with only
115 HOST_BITS_PER_WIDE_INT/2 bits stored in each word, as a positive number. */
118 ((x) & (((unsigned HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT/2)) - 1))
119 #define HIGHPART(x) \
120 ((unsigned HOST_WIDE_INT) (x) >> HOST_BITS_PER_WIDE_INT/2)
121 #define BASE ((unsigned HOST_WIDE_INT) 1 << HOST_BITS_PER_WIDE_INT/2)
123 /* Unpack a two-word integer into 4 words.
124 LOW and HI are the integer, as two `HOST_WIDE_INT' pieces.
125 WORDS points to the array of HOST_WIDE_INTs. */
128 encode (words, low, hi)
129 HOST_WIDE_INT *words;
130 HOST_WIDE_INT low, hi;
132 words[0] = LOWPART (low);
133 words[1] = HIGHPART (low);
134 words[2] = LOWPART (hi);
135 words[3] = HIGHPART (hi);
138 /* Pack an array of 4 words into a two-word integer.
139 WORDS points to the array of words.
140 The integer is stored into *LOW and *HI as two `HOST_WIDE_INT' pieces. */
143 decode (words, low, hi)
144 HOST_WIDE_INT *words;
145 HOST_WIDE_INT *low, *hi;
147 *low = words[0] | words[1] * BASE;
148 *hi = words[2] | words[3] * BASE;
151 /* Make the integer constant T valid for its type
152 by setting to 0 or 1 all the bits in the constant
153 that don't belong in the type.
154 Yield 1 if a signed overflow occurs, 0 otherwise.
155 If OVERFLOW is nonzero, a signed overflow has already occurred
156 in calculating T, so propagate it.
158 Make the real constant T valid for its type by calling CHECK_FLOAT_VALUE,
162 force_fit_type (t, overflow)
166 HOST_WIDE_INT low, high;
169 if (TREE_CODE (t) == REAL_CST)
171 #ifdef CHECK_FLOAT_VALUE
172 CHECK_FLOAT_VALUE (TYPE_MODE (TREE_TYPE (t)), TREE_REAL_CST (t),
178 else if (TREE_CODE (t) != INTEGER_CST)
181 low = TREE_INT_CST_LOW (t);
182 high = TREE_INT_CST_HIGH (t);
184 if (POINTER_TYPE_P (TREE_TYPE (t)))
187 prec = TYPE_PRECISION (TREE_TYPE (t));
189 /* First clear all bits that are beyond the type's precision. */
191 if (prec == 2 * HOST_BITS_PER_WIDE_INT)
193 else if (prec > HOST_BITS_PER_WIDE_INT)
195 TREE_INT_CST_HIGH (t)
196 &= ~((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
200 TREE_INT_CST_HIGH (t) = 0;
201 if (prec < HOST_BITS_PER_WIDE_INT)
202 TREE_INT_CST_LOW (t) &= ~((HOST_WIDE_INT) (-1) << prec);
205 /* Unsigned types do not suffer sign extension or overflow. */
206 if (TREE_UNSIGNED (TREE_TYPE (t)))
209 /* If the value's sign bit is set, extend the sign. */
210 if (prec != 2 * HOST_BITS_PER_WIDE_INT
211 && (prec > HOST_BITS_PER_WIDE_INT
212 ? (TREE_INT_CST_HIGH (t)
213 & ((HOST_WIDE_INT) 1 << (prec - HOST_BITS_PER_WIDE_INT - 1)))
214 : TREE_INT_CST_LOW (t) & ((HOST_WIDE_INT) 1 << (prec - 1))))
216 /* Value is negative:
217 set to 1 all the bits that are outside this type's precision. */
218 if (prec > HOST_BITS_PER_WIDE_INT)
220 TREE_INT_CST_HIGH (t)
221 |= ((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
225 TREE_INT_CST_HIGH (t) = -1;
226 if (prec < HOST_BITS_PER_WIDE_INT)
227 TREE_INT_CST_LOW (t) |= ((HOST_WIDE_INT) (-1) << prec);
231 /* Yield nonzero if signed overflow occurred. */
233 ((overflow | (low ^ TREE_INT_CST_LOW (t)) | (high ^ TREE_INT_CST_HIGH (t)))
237 /* Add two doubleword integers with doubleword result.
238 Each argument is given as two `HOST_WIDE_INT' pieces.
239 One argument is L1 and H1; the other, L2 and H2.
240 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
243 add_double (l1, h1, l2, h2, lv, hv)
244 HOST_WIDE_INT l1, h1, l2, h2;
245 HOST_WIDE_INT *lv, *hv;
250 h = h1 + h2 + ((unsigned HOST_WIDE_INT) l < l1);
254 return overflow_sum_sign (h1, h2, h);
257 /* Negate a doubleword integer with doubleword result.
258 Return nonzero if the operation overflows, assuming it's signed.
259 The argument is given as two `HOST_WIDE_INT' pieces in L1 and H1.
260 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
263 neg_double (l1, h1, lv, hv)
264 HOST_WIDE_INT l1, h1;
265 HOST_WIDE_INT *lv, *hv;
271 return (*hv & h1) < 0;
281 /* Multiply two doubleword integers with doubleword result.
282 Return nonzero if the operation overflows, assuming it's signed.
283 Each argument is given as two `HOST_WIDE_INT' pieces.
284 One argument is L1 and H1; the other, L2 and H2.
285 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
288 mul_double (l1, h1, l2, h2, lv, hv)
289 HOST_WIDE_INT l1, h1, l2, h2;
290 HOST_WIDE_INT *lv, *hv;
292 HOST_WIDE_INT arg1[4];
293 HOST_WIDE_INT arg2[4];
294 HOST_WIDE_INT prod[4 * 2];
295 register unsigned HOST_WIDE_INT carry;
296 register int i, j, k;
297 HOST_WIDE_INT toplow, tophigh, neglow, neghigh;
299 encode (arg1, l1, h1);
300 encode (arg2, l2, h2);
302 bzero ((char *) prod, sizeof prod);
304 for (i = 0; i < 4; i++)
307 for (j = 0; j < 4; j++)
310 /* This product is <= 0xFFFE0001, the sum <= 0xFFFF0000. */
311 carry += arg1[i] * arg2[j];
312 /* Since prod[p] < 0xFFFF, this sum <= 0xFFFFFFFF. */
314 prod[k] = LOWPART (carry);
315 carry = HIGHPART (carry);
320 decode (prod, lv, hv); /* This ignores prod[4] through prod[4*2-1] */
322 /* Check for overflow by calculating the top half of the answer in full;
323 it should agree with the low half's sign bit. */
324 decode (prod+4, &toplow, &tophigh);
327 neg_double (l2, h2, &neglow, &neghigh);
328 add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh);
332 neg_double (l1, h1, &neglow, &neghigh);
333 add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh);
335 return (*hv < 0 ? ~(toplow & tophigh) : toplow | tophigh) != 0;
338 /* Shift the doubleword integer in L1, H1 left by COUNT places
339 keeping only PREC bits of result.
340 Shift right if COUNT is negative.
341 ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
342 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
345 lshift_double (l1, h1, count, prec, lv, hv, arith)
346 HOST_WIDE_INT l1, h1, count;
348 HOST_WIDE_INT *lv, *hv;
353 rshift_double (l1, h1, - count, prec, lv, hv, arith);
357 #ifdef SHIFT_COUNT_TRUNCATED
358 if (SHIFT_COUNT_TRUNCATED)
362 if (count >= HOST_BITS_PER_WIDE_INT)
364 *hv = (unsigned HOST_WIDE_INT) l1 << (count - HOST_BITS_PER_WIDE_INT);
369 *hv = (((unsigned HOST_WIDE_INT) h1 << count)
370 | ((unsigned HOST_WIDE_INT) l1 >> (HOST_BITS_PER_WIDE_INT - count - 1) >> 1));
371 *lv = (unsigned HOST_WIDE_INT) l1 << count;
375 /* Shift the doubleword integer in L1, H1 right by COUNT places
376 keeping only PREC bits of result. COUNT must be positive.
377 ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
378 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
381 rshift_double (l1, h1, count, prec, lv, hv, arith)
382 HOST_WIDE_INT l1, h1, count;
383 int prec ATTRIBUTE_UNUSED;
384 HOST_WIDE_INT *lv, *hv;
387 unsigned HOST_WIDE_INT signmask;
389 ? -((unsigned HOST_WIDE_INT) h1 >> (HOST_BITS_PER_WIDE_INT - 1))
392 #ifdef SHIFT_COUNT_TRUNCATED
393 if (SHIFT_COUNT_TRUNCATED)
397 if (count >= HOST_BITS_PER_WIDE_INT)
400 *lv = ((signmask << (2 * HOST_BITS_PER_WIDE_INT - count - 1) << 1)
401 | ((unsigned HOST_WIDE_INT) h1 >> (count - HOST_BITS_PER_WIDE_INT)));
405 *lv = (((unsigned HOST_WIDE_INT) l1 >> count)
406 | ((unsigned HOST_WIDE_INT) h1 << (HOST_BITS_PER_WIDE_INT - count - 1) << 1));
407 *hv = ((signmask << (HOST_BITS_PER_WIDE_INT - count))
408 | ((unsigned HOST_WIDE_INT) h1 >> count));
412 /* Rotate the doubleword integer in L1, H1 left by COUNT places
413 keeping only PREC bits of result.
414 Rotate right if COUNT is negative.
415 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
418 lrotate_double (l1, h1, count, prec, lv, hv)
419 HOST_WIDE_INT l1, h1, count;
421 HOST_WIDE_INT *lv, *hv;
423 HOST_WIDE_INT s1l, s1h, s2l, s2h;
429 lshift_double (l1, h1, count, prec, &s1l, &s1h, 0);
430 rshift_double (l1, h1, prec - count, prec, &s2l, &s2h, 0);
435 /* Rotate the doubleword integer in L1, H1 left by COUNT places
436 keeping only PREC bits of result. COUNT must be positive.
437 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
440 rrotate_double (l1, h1, count, prec, lv, hv)
441 HOST_WIDE_INT l1, h1, count;
443 HOST_WIDE_INT *lv, *hv;
445 HOST_WIDE_INT s1l, s1h, s2l, s2h;
451 rshift_double (l1, h1, count, prec, &s1l, &s1h, 0);
452 lshift_double (l1, h1, prec - count, prec, &s2l, &s2h, 0);
457 /* Divide doubleword integer LNUM, HNUM by doubleword integer LDEN, HDEN
458 for a quotient (stored in *LQUO, *HQUO) and remainder (in *LREM, *HREM).
459 CODE is a tree code for a kind of division, one of
460 TRUNC_DIV_EXPR, FLOOR_DIV_EXPR, CEIL_DIV_EXPR, ROUND_DIV_EXPR
462 It controls how the quotient is rounded to a integer.
463 Return nonzero if the operation overflows.
464 UNS nonzero says do unsigned division. */
467 div_and_round_double (code, uns,
468 lnum_orig, hnum_orig, lden_orig, hden_orig,
469 lquo, hquo, lrem, hrem)
472 HOST_WIDE_INT lnum_orig, hnum_orig; /* num == numerator == dividend */
473 HOST_WIDE_INT lden_orig, hden_orig; /* den == denominator == divisor */
474 HOST_WIDE_INT *lquo, *hquo, *lrem, *hrem;
477 HOST_WIDE_INT num[4 + 1]; /* extra element for scaling. */
478 HOST_WIDE_INT den[4], quo[4];
480 unsigned HOST_WIDE_INT work;
481 register unsigned HOST_WIDE_INT carry = 0;
482 HOST_WIDE_INT lnum = lnum_orig;
483 HOST_WIDE_INT hnum = hnum_orig;
484 HOST_WIDE_INT lden = lden_orig;
485 HOST_WIDE_INT hden = hden_orig;
488 if ((hden == 0) && (lden == 0))
489 overflow = 1, lden = 1;
491 /* calculate quotient sign and convert operands to unsigned. */
497 /* (minimum integer) / (-1) is the only overflow case. */
498 if (neg_double (lnum, hnum, &lnum, &hnum) && (lden & hden) == -1)
504 neg_double (lden, hden, &lden, &hden);
508 if (hnum == 0 && hden == 0)
509 { /* single precision */
511 /* This unsigned division rounds toward zero. */
512 *lquo = lnum / (unsigned HOST_WIDE_INT) lden;
517 { /* trivial case: dividend < divisor */
518 /* hden != 0 already checked. */
525 bzero ((char *) quo, sizeof quo);
527 bzero ((char *) num, sizeof num); /* to zero 9th element */
528 bzero ((char *) den, sizeof den);
530 encode (num, lnum, hnum);
531 encode (den, lden, hden);
533 /* Special code for when the divisor < BASE. */
534 if (hden == 0 && lden < (HOST_WIDE_INT) BASE)
536 /* hnum != 0 already checked. */
537 for (i = 4 - 1; i >= 0; i--)
539 work = num[i] + carry * BASE;
540 quo[i] = work / (unsigned HOST_WIDE_INT) lden;
541 carry = work % (unsigned HOST_WIDE_INT) lden;
546 /* Full double precision division,
547 with thanks to Don Knuth's "Seminumerical Algorithms". */
548 int num_hi_sig, den_hi_sig;
549 unsigned HOST_WIDE_INT quo_est, scale;
551 /* Find the highest non-zero divisor digit. */
552 for (i = 4 - 1; ; i--)
558 /* Insure that the first digit of the divisor is at least BASE/2.
559 This is required by the quotient digit estimation algorithm. */
561 scale = BASE / (den[den_hi_sig] + 1);
562 if (scale > 1) { /* scale divisor and dividend */
564 for (i = 0; i <= 4 - 1; i++) {
565 work = (num[i] * scale) + carry;
566 num[i] = LOWPART (work);
567 carry = HIGHPART (work);
570 for (i = 0; i <= 4 - 1; i++) {
571 work = (den[i] * scale) + carry;
572 den[i] = LOWPART (work);
573 carry = HIGHPART (work);
574 if (den[i] != 0) den_hi_sig = i;
581 for (i = num_hi_sig - den_hi_sig - 1; i >= 0; i--) {
582 /* guess the next quotient digit, quo_est, by dividing the first
583 two remaining dividend digits by the high order quotient digit.
584 quo_est is never low and is at most 2 high. */
585 unsigned HOST_WIDE_INT tmp;
587 num_hi_sig = i + den_hi_sig + 1;
588 work = num[num_hi_sig] * BASE + num[num_hi_sig - 1];
589 if (num[num_hi_sig] != den[den_hi_sig])
590 quo_est = work / den[den_hi_sig];
594 /* refine quo_est so it's usually correct, and at most one high. */
595 tmp = work - quo_est * den[den_hi_sig];
597 && den[den_hi_sig - 1] * quo_est > (tmp * BASE + num[num_hi_sig - 2]))
600 /* Try QUO_EST as the quotient digit, by multiplying the
601 divisor by QUO_EST and subtracting from the remaining dividend.
602 Keep in mind that QUO_EST is the I - 1st digit. */
605 for (j = 0; j <= den_hi_sig; j++)
607 work = quo_est * den[j] + carry;
608 carry = HIGHPART (work);
609 work = num[i + j] - LOWPART (work);
610 num[i + j] = LOWPART (work);
611 carry += HIGHPART (work) != 0;
614 /* if quo_est was high by one, then num[i] went negative and
615 we need to correct things. */
617 if (num[num_hi_sig] < carry)
620 carry = 0; /* add divisor back in */
621 for (j = 0; j <= den_hi_sig; j++)
623 work = num[i + j] + den[j] + carry;
624 carry = HIGHPART (work);
625 num[i + j] = LOWPART (work);
627 num [num_hi_sig] += carry;
630 /* store the quotient digit. */
635 decode (quo, lquo, hquo);
638 /* if result is negative, make it so. */
640 neg_double (*lquo, *hquo, lquo, hquo);
642 /* compute trial remainder: rem = num - (quo * den) */
643 mul_double (*lquo, *hquo, lden_orig, hden_orig, lrem, hrem);
644 neg_double (*lrem, *hrem, lrem, hrem);
645 add_double (lnum_orig, hnum_orig, *lrem, *hrem, lrem, hrem);
650 case TRUNC_MOD_EXPR: /* round toward zero */
651 case EXACT_DIV_EXPR: /* for this one, it shouldn't matter */
655 case FLOOR_MOD_EXPR: /* round toward negative infinity */
656 if (quo_neg && (*lrem != 0 || *hrem != 0)) /* ratio < 0 && rem != 0 */
659 add_double (*lquo, *hquo, (HOST_WIDE_INT) -1, (HOST_WIDE_INT) -1,
662 else return overflow;
666 case CEIL_MOD_EXPR: /* round toward positive infinity */
667 if (!quo_neg && (*lrem != 0 || *hrem != 0)) /* ratio > 0 && rem != 0 */
669 add_double (*lquo, *hquo, (HOST_WIDE_INT) 1, (HOST_WIDE_INT) 0,
672 else return overflow;
676 case ROUND_MOD_EXPR: /* round to closest integer */
678 HOST_WIDE_INT labs_rem = *lrem, habs_rem = *hrem;
679 HOST_WIDE_INT labs_den = lden, habs_den = hden, ltwice, htwice;
681 /* get absolute values */
682 if (*hrem < 0) neg_double (*lrem, *hrem, &labs_rem, &habs_rem);
683 if (hden < 0) neg_double (lden, hden, &labs_den, &habs_den);
685 /* if (2 * abs (lrem) >= abs (lden)) */
686 mul_double ((HOST_WIDE_INT) 2, (HOST_WIDE_INT) 0,
687 labs_rem, habs_rem, <wice, &htwice);
688 if (((unsigned HOST_WIDE_INT) habs_den
689 < (unsigned HOST_WIDE_INT) htwice)
690 || (((unsigned HOST_WIDE_INT) habs_den
691 == (unsigned HOST_WIDE_INT) htwice)
692 && ((HOST_WIDE_INT unsigned) labs_den
693 < (unsigned HOST_WIDE_INT) ltwice)))
697 add_double (*lquo, *hquo,
698 (HOST_WIDE_INT) -1, (HOST_WIDE_INT) -1, lquo, hquo);
701 add_double (*lquo, *hquo, (HOST_WIDE_INT) 1, (HOST_WIDE_INT) 0,
704 else return overflow;
712 /* compute true remainder: rem = num - (quo * den) */
713 mul_double (*lquo, *hquo, lden_orig, hden_orig, lrem, hrem);
714 neg_double (*lrem, *hrem, lrem, hrem);
715 add_double (lnum_orig, hnum_orig, *lrem, *hrem, lrem, hrem);
719 #ifndef REAL_ARITHMETIC
720 /* Effectively truncate a real value to represent the nearest possible value
721 in a narrower mode. The result is actually represented in the same data
722 type as the argument, but its value is usually different.
724 A trap may occur during the FP operations and it is the responsibility
725 of the calling function to have a handler established. */
728 real_value_truncate (mode, arg)
729 enum machine_mode mode;
732 return REAL_VALUE_TRUNCATE (mode, arg);
735 #if TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
737 /* Check for infinity in an IEEE double precision number. */
743 /* The IEEE 64-bit double format. */
748 unsigned exponent : 11;
749 unsigned mantissa1 : 20;
754 unsigned mantissa1 : 20;
755 unsigned exponent : 11;
761 if (u.big_endian.sign == 1)
764 return (u.big_endian.exponent == 2047
765 && u.big_endian.mantissa1 == 0
766 && u.big_endian.mantissa2 == 0);
771 return (u.little_endian.exponent == 2047
772 && u.little_endian.mantissa1 == 0
773 && u.little_endian.mantissa2 == 0);
777 /* Check whether an IEEE double precision number is a NaN. */
783 /* The IEEE 64-bit double format. */
788 unsigned exponent : 11;
789 unsigned mantissa1 : 20;
794 unsigned mantissa1 : 20;
795 unsigned exponent : 11;
801 if (u.big_endian.sign == 1)
804 return (u.big_endian.exponent == 2047
805 && (u.big_endian.mantissa1 != 0
806 || u.big_endian.mantissa2 != 0));
811 return (u.little_endian.exponent == 2047
812 && (u.little_endian.mantissa1 != 0
813 || u.little_endian.mantissa2 != 0));
817 /* Check for a negative IEEE double precision number. */
823 /* The IEEE 64-bit double format. */
828 unsigned exponent : 11;
829 unsigned mantissa1 : 20;
834 unsigned mantissa1 : 20;
835 unsigned exponent : 11;
841 if (u.big_endian.sign == 1)
844 return u.big_endian.sign;
849 return u.little_endian.sign;
852 #else /* Target not IEEE */
854 /* Let's assume other float formats don't have infinity.
855 (This can be overridden by redefining REAL_VALUE_ISINF.) */
863 /* Let's assume other float formats don't have NaNs.
864 (This can be overridden by redefining REAL_VALUE_ISNAN.) */
872 /* Let's assume other float formats don't have minus zero.
873 (This can be overridden by redefining REAL_VALUE_NEGATIVE.) */
880 #endif /* Target not IEEE */
882 /* Try to change R into its exact multiplicative inverse in machine mode
883 MODE. Return nonzero function value if successful. */
886 exact_real_inverse (mode, r)
887 enum machine_mode mode;
898 /* Usually disable if bounds checks are not reliable. */
899 if ((HOST_FLOAT_FORMAT != TARGET_FLOAT_FORMAT) && !flag_pretend_float)
902 /* Set array index to the less significant bits in the unions, depending
903 on the endian-ness of the host doubles.
904 Disable if insufficient information on the data structure. */
905 #if HOST_FLOAT_FORMAT == UNKNOWN_FLOAT_FORMAT
908 #if HOST_FLOAT_FORMAT == VAX_FLOAT_FORMAT
911 #if HOST_FLOAT_FORMAT == IBM_FLOAT_FORMAT
914 #define K (2 * HOST_FLOAT_WORDS_BIG_ENDIAN)
919 if (setjmp (float_error))
921 /* Don't do the optimization if there was an arithmetic error. */
923 set_float_handler (NULL_PTR);
926 set_float_handler (float_error);
928 /* Domain check the argument. */
934 if (REAL_VALUE_ISINF (x.d) || REAL_VALUE_ISNAN (x.d))
938 /* Compute the reciprocal and check for numerical exactness.
939 It is unnecessary to check all the significand bits to determine
940 whether X is a power of 2. If X is not, then it is impossible for
941 the bottom half significand of both X and 1/X to be all zero bits.
942 Hence we ignore the data structure of the top half and examine only
943 the low order bits of the two significands. */
945 if (x.i[K] != 0 || x.i[K + 1] != 0 || t.i[K] != 0 || t.i[K + 1] != 0)
948 /* Truncate to the required mode and range-check the result. */
949 y.d = REAL_VALUE_TRUNCATE (mode, t.d);
950 #ifdef CHECK_FLOAT_VALUE
952 if (CHECK_FLOAT_VALUE (mode, y.d, i))
956 /* Fail if truncation changed the value. */
957 if (y.d != t.d || y.d == 0.0)
961 if (REAL_VALUE_ISINF (y.d) || REAL_VALUE_ISNAN (y.d))
965 /* Output the reciprocal and return success flag. */
966 set_float_handler (NULL_PTR);
972 /* Convert C9X hexadecimal floating point string constant S. Return
973 real value type in mode MODE. This function uses the host computer's
974 fp arithmetic when there is no REAL_ARITHMETIC. */
977 real_hex_to_f (s, mode)
979 enum machine_mode mode;
983 unsigned HOST_WIDE_INT low, high;
984 int frexpon, expon, shcount, nrmcount, k;
985 int sign, expsign, decpt, isfloat, isldouble, gotp, lost;
995 while (*p == ' ' || *p == '\t')
998 /* Sign, if any, comes first. */
1006 /* The string is supposed to start with 0x or 0X . */
1010 if (*p == 'x' || *p == 'X')
1023 lost = 0; /* Nonzero low order bits shifted out and discarded. */
1024 frexpon = 0; /* Bits after the decimal point. */
1025 expon = 0; /* Value of exponent. */
1026 decpt = 0; /* How many decimal points. */
1027 gotp = 0; /* How many P's. */
1029 while ((c = *p) != '\0')
1031 if ((c >= '0' && c <= '9') || (c >= 'A' && c <= 'F')
1032 || (c >= 'a' && c <= 'f'))
1042 if ((high & 0xf0000000) == 0)
1044 high = (high << 4) + ((low >> 28) & 15);
1045 low = (low << 4) + k;
1052 /* Record nonzero lost bits. */
1064 else if (c == 'p' || c == 'P')
1068 /* Sign of exponent. */
1074 /* Value of exponent.
1075 The exponent field is a decimal integer. */
1078 k = (*p++ & 0x7f) - '0';
1079 expon = 10 * expon + k;
1082 /* F suffix is ambiguous in the significand part
1083 so it must appear after the decimal exponent field. */
1084 if (*p == 'f' || *p == 'F')
1091 else if (c == 'l' || c == 'L')
1100 /* Abort if last character read was not legitimate. */
1102 if ((c != '\0' && c != ' ' && c != '\n' && c != '\r') || (decpt > 1))
1104 /* There must be either one decimal point or one p. */
1105 if (decpt == 0 && gotp == 0)
1108 if ((high == 0) && (low == 0))
1121 /* Leave a high guard bit for carry-out. */
1122 if ((high & 0x80000000) != 0)
1125 low = (low >> 1) | (high << 31);
1129 if ((high & 0xffff8000) == 0)
1131 high = (high << 16) + ((low >> 16) & 0xffff);
1135 while ((high & 0xc0000000) == 0)
1137 high = (high << 1) + ((low >> 31) & 1);
1141 if (isfloat || GET_MODE_SIZE(mode) == UNITS_PER_WORD)
1143 /* Keep 24 bits precision, bits 0x7fffff80.
1144 Rounding bit is 0x40. */
1145 lost = lost | low | (high & 0x3f);
1149 if ((high & 0x80) || lost)
1156 /* We need real.c to do long double formats, so here default
1157 to double precision. */
1158 #if HOST_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
1160 Keep 53 bits precision, bits 0x7fffffff fffffc00.
1161 Rounding bit is low word 0x200. */
1162 lost = lost | (low & 0x1ff);
1165 if ((low & 0x400) || lost)
1167 low = (low + 0x200) & 0xfffffc00;
1174 /* Assume it's a VAX with 56-bit significand,
1175 bits 0x7fffffff ffffff80. */
1176 lost = lost | (low & 0x7f);
1179 if ((low & 0x80) || lost)
1181 low = (low + 0x40) & 0xffffff80;
1190 ip = REAL_VALUE_LDEXP (ip, 32) + (double) low;
1191 /* Apply shifts and exponent value as power of 2. */
1192 ip = REAL_VALUE_LDEXP (ip, expon - (nrmcount + frexpon));
1199 #endif /* no REAL_ARITHMETIC */
1201 /* Split a tree IN into a constant and a variable part
1202 that could be combined with CODE to make IN.
1203 CODE must be a commutative arithmetic operation.
1204 Store the constant part into *CONP and the variable in &VARP.
1205 Return 1 if this was done; zero means the tree IN did not decompose
1208 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR.
1209 Therefore, we must tell the caller whether the variable part
1210 was subtracted. We do this by storing 1 or -1 into *VARSIGNP.
1211 The value stored is the coefficient for the variable term.
1212 The constant term we return should always be added;
1213 we negate it if necessary. */
1216 split_tree (in, code, varp, conp, varsignp)
1218 enum tree_code code;
1222 register tree outtype = TREE_TYPE (in);
1226 /* Strip any conversions that don't change the machine mode. */
1227 while ((TREE_CODE (in) == NOP_EXPR
1228 || TREE_CODE (in) == CONVERT_EXPR)
1229 && (TYPE_MODE (TREE_TYPE (in))
1230 == TYPE_MODE (TREE_TYPE (TREE_OPERAND (in, 0)))))
1231 in = TREE_OPERAND (in, 0);
1233 if (TREE_CODE (in) == code
1234 || (! FLOAT_TYPE_P (TREE_TYPE (in))
1235 /* We can associate addition and subtraction together
1236 (even though the C standard doesn't say so)
1237 for integers because the value is not affected.
1238 For reals, the value might be affected, so we can't. */
1239 && ((code == PLUS_EXPR && TREE_CODE (in) == MINUS_EXPR)
1240 || (code == MINUS_EXPR && TREE_CODE (in) == PLUS_EXPR))))
1242 enum tree_code code = TREE_CODE (TREE_OPERAND (in, 0));
1243 if (code == INTEGER_CST)
1245 *conp = TREE_OPERAND (in, 0);
1246 *varp = TREE_OPERAND (in, 1);
1247 if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype)
1248 && TREE_TYPE (*varp) != outtype)
1249 *varp = convert (outtype, *varp);
1250 *varsignp = (TREE_CODE (in) == MINUS_EXPR) ? -1 : 1;
1253 if (TREE_CONSTANT (TREE_OPERAND (in, 1)))
1255 *conp = TREE_OPERAND (in, 1);
1256 *varp = TREE_OPERAND (in, 0);
1258 if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype)
1259 && TREE_TYPE (*varp) != outtype)
1260 *varp = convert (outtype, *varp);
1261 if (TREE_CODE (in) == MINUS_EXPR)
1263 /* If operation is subtraction and constant is second,
1264 must negate it to get an additive constant.
1265 And this cannot be done unless it is a manifest constant.
1266 It could also be the address of a static variable.
1267 We cannot negate that, so give up. */
1268 if (TREE_CODE (*conp) == INTEGER_CST)
1269 /* Subtracting from integer_zero_node loses for long long. */
1270 *conp = fold (build1 (NEGATE_EXPR, TREE_TYPE (*conp), *conp));
1276 if (TREE_CONSTANT (TREE_OPERAND (in, 0)))
1278 *conp = TREE_OPERAND (in, 0);
1279 *varp = TREE_OPERAND (in, 1);
1280 if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype)
1281 && TREE_TYPE (*varp) != outtype)
1282 *varp = convert (outtype, *varp);
1283 *varsignp = (TREE_CODE (in) == MINUS_EXPR) ? -1 : 1;
1290 /* Combine two integer constants ARG1 and ARG2 under operation CODE
1291 to produce a new constant.
1293 If NOTRUNC is nonzero, do not truncate the result to fit the data type.
1294 If FORSIZE is nonzero, compute overflow for unsigned types. */
1297 int_const_binop (code, arg1, arg2, notrunc, forsize)
1298 enum tree_code code;
1299 register tree arg1, arg2;
1300 int notrunc, forsize;
1302 HOST_WIDE_INT int1l, int1h, int2l, int2h;
1303 HOST_WIDE_INT low, hi;
1304 HOST_WIDE_INT garbagel, garbageh;
1306 int uns = TREE_UNSIGNED (TREE_TYPE (arg1));
1308 int no_overflow = 0;
1310 int1l = TREE_INT_CST_LOW (arg1);
1311 int1h = TREE_INT_CST_HIGH (arg1);
1312 int2l = TREE_INT_CST_LOW (arg2);
1313 int2h = TREE_INT_CST_HIGH (arg2);
1318 low = int1l | int2l, hi = int1h | int2h;
1322 low = int1l ^ int2l, hi = int1h ^ int2h;
1326 low = int1l & int2l, hi = int1h & int2h;
1329 case BIT_ANDTC_EXPR:
1330 low = int1l & ~int2l, hi = int1h & ~int2h;
1336 /* It's unclear from the C standard whether shifts can overflow.
1337 The following code ignores overflow; perhaps a C standard
1338 interpretation ruling is needed. */
1339 lshift_double (int1l, int1h, int2l,
1340 TYPE_PRECISION (TREE_TYPE (arg1)),
1349 lrotate_double (int1l, int1h, int2l,
1350 TYPE_PRECISION (TREE_TYPE (arg1)),
1355 overflow = add_double (int1l, int1h, int2l, int2h, &low, &hi);
1359 neg_double (int2l, int2h, &low, &hi);
1360 add_double (int1l, int1h, low, hi, &low, &hi);
1361 overflow = overflow_sum_sign (hi, int2h, int1h);
1365 overflow = mul_double (int1l, int1h, int2l, int2h, &low, &hi);
1368 case TRUNC_DIV_EXPR:
1369 case FLOOR_DIV_EXPR: case CEIL_DIV_EXPR:
1370 case EXACT_DIV_EXPR:
1371 /* This is a shortcut for a common special case. */
1372 if (int2h == 0 && int2l > 0
1373 && ! TREE_CONSTANT_OVERFLOW (arg1)
1374 && ! TREE_CONSTANT_OVERFLOW (arg2)
1375 && int1h == 0 && int1l >= 0)
1377 if (code == CEIL_DIV_EXPR)
1379 low = int1l / int2l, hi = 0;
1383 /* ... fall through ... */
1385 case ROUND_DIV_EXPR:
1386 if (int2h == 0 && int2l == 1)
1388 low = int1l, hi = int1h;
1391 if (int1l == int2l && int1h == int2h
1392 && ! (int1l == 0 && int1h == 0))
1397 overflow = div_and_round_double (code, uns,
1398 int1l, int1h, int2l, int2h,
1399 &low, &hi, &garbagel, &garbageh);
1402 case TRUNC_MOD_EXPR:
1403 case FLOOR_MOD_EXPR: case CEIL_MOD_EXPR:
1404 /* This is a shortcut for a common special case. */
1405 if (int2h == 0 && int2l > 0
1406 && ! TREE_CONSTANT_OVERFLOW (arg1)
1407 && ! TREE_CONSTANT_OVERFLOW (arg2)
1408 && int1h == 0 && int1l >= 0)
1410 if (code == CEIL_MOD_EXPR)
1412 low = int1l % int2l, hi = 0;
1416 /* ... fall through ... */
1418 case ROUND_MOD_EXPR:
1419 overflow = div_and_round_double (code, uns,
1420 int1l, int1h, int2l, int2h,
1421 &garbagel, &garbageh, &low, &hi);
1428 low = (((unsigned HOST_WIDE_INT) int1h
1429 < (unsigned HOST_WIDE_INT) int2h)
1430 || (((unsigned HOST_WIDE_INT) int1h
1431 == (unsigned HOST_WIDE_INT) int2h)
1432 && ((unsigned HOST_WIDE_INT) int1l
1433 < (unsigned HOST_WIDE_INT) int2l)));
1437 low = ((int1h < int2h)
1438 || ((int1h == int2h)
1439 && ((unsigned HOST_WIDE_INT) int1l
1440 < (unsigned HOST_WIDE_INT) int2l)));
1442 if (low == (code == MIN_EXPR))
1443 low = int1l, hi = int1h;
1445 low = int2l, hi = int2h;
1452 if (TREE_TYPE (arg1) == sizetype && hi == 0
1454 && (TYPE_MAX_VALUE (sizetype) == NULL
1455 || low <= TREE_INT_CST_LOW (TYPE_MAX_VALUE (sizetype)))
1457 && ! TREE_OVERFLOW (arg1) && ! TREE_OVERFLOW (arg2))
1461 t = build_int_2 (low, hi);
1462 TREE_TYPE (t) = TREE_TYPE (arg1);
1466 = ((notrunc ? (!uns || forsize) && overflow
1467 : force_fit_type (t, (!uns || forsize) && overflow) && ! no_overflow)
1468 | TREE_OVERFLOW (arg1)
1469 | TREE_OVERFLOW (arg2));
1470 /* If we're doing a size calculation, unsigned arithmetic does overflow.
1471 So check if force_fit_type truncated the value. */
1473 && ! TREE_OVERFLOW (t)
1474 && (TREE_INT_CST_HIGH (t) != hi
1475 || TREE_INT_CST_LOW (t) != low))
1476 TREE_OVERFLOW (t) = 1;
1477 TREE_CONSTANT_OVERFLOW (t) = (TREE_OVERFLOW (t)
1478 | TREE_CONSTANT_OVERFLOW (arg1)
1479 | TREE_CONSTANT_OVERFLOW (arg2));
1487 REAL_VALUE_TYPE d1, d2;
1488 enum tree_code code;
1494 const_binop_1 (data)
1497 struct cb_args * args = (struct cb_args *) data;
1498 REAL_VALUE_TYPE value;
1500 #ifdef REAL_ARITHMETIC
1501 REAL_ARITHMETIC (value, args->code, args->d1, args->d2);
1506 value = args->d1 + args->d2;
1510 value = args->d1 - args->d2;
1514 value = args->d1 * args->d2;
1518 #ifndef REAL_INFINITY
1523 value = args->d1 / args->d2;
1527 value = MIN (args->d1, args->d2);
1531 value = MAX (args->d1, args->d2);
1537 #endif /* no REAL_ARITHMETIC */
1539 build_real (TREE_TYPE (args->arg1),
1540 real_value_truncate (TYPE_MODE (TREE_TYPE (args->arg1)),
1544 /* Combine two constants ARG1 and ARG2 under operation CODE
1545 to produce a new constant.
1546 We assume ARG1 and ARG2 have the same data type,
1547 or at least are the same kind of constant and the same machine mode.
1549 If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
1552 const_binop (code, arg1, arg2, notrunc)
1553 enum tree_code code;
1554 register tree arg1, arg2;
1557 STRIP_NOPS (arg1); STRIP_NOPS (arg2);
1559 if (TREE_CODE (arg1) == INTEGER_CST)
1560 return int_const_binop (code, arg1, arg2, notrunc, 0);
1562 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
1563 if (TREE_CODE (arg1) == REAL_CST)
1569 struct cb_args args;
1571 d1 = TREE_REAL_CST (arg1);
1572 d2 = TREE_REAL_CST (arg2);
1574 /* If either operand is a NaN, just return it. Otherwise, set up
1575 for floating-point trap; we return an overflow. */
1576 if (REAL_VALUE_ISNAN (d1))
1578 else if (REAL_VALUE_ISNAN (d2))
1581 /* Setup input for const_binop_1() */
1587 if (do_float_handler (const_binop_1, (PTR) &args))
1589 /* Receive output from const_binop_1() */
1594 /* We got an exception from const_binop_1() */
1595 t = copy_node (arg1);
1600 = (force_fit_type (t, overflow)
1601 | TREE_OVERFLOW (arg1) | TREE_OVERFLOW (arg2));
1602 TREE_CONSTANT_OVERFLOW (t)
1604 | TREE_CONSTANT_OVERFLOW (arg1)
1605 | TREE_CONSTANT_OVERFLOW (arg2);
1608 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
1609 if (TREE_CODE (arg1) == COMPLEX_CST)
1611 register tree type = TREE_TYPE (arg1);
1612 register tree r1 = TREE_REALPART (arg1);
1613 register tree i1 = TREE_IMAGPART (arg1);
1614 register tree r2 = TREE_REALPART (arg2);
1615 register tree i2 = TREE_IMAGPART (arg2);
1621 t = build_complex (type,
1622 const_binop (PLUS_EXPR, r1, r2, notrunc),
1623 const_binop (PLUS_EXPR, i1, i2, notrunc));
1627 t = build_complex (type,
1628 const_binop (MINUS_EXPR, r1, r2, notrunc),
1629 const_binop (MINUS_EXPR, i1, i2, notrunc));
1633 t = build_complex (type,
1634 const_binop (MINUS_EXPR,
1635 const_binop (MULT_EXPR,
1637 const_binop (MULT_EXPR,
1640 const_binop (PLUS_EXPR,
1641 const_binop (MULT_EXPR,
1643 const_binop (MULT_EXPR,
1650 register tree magsquared
1651 = const_binop (PLUS_EXPR,
1652 const_binop (MULT_EXPR, r2, r2, notrunc),
1653 const_binop (MULT_EXPR, i2, i2, notrunc),
1656 t = build_complex (type,
1658 (INTEGRAL_TYPE_P (TREE_TYPE (r1))
1659 ? TRUNC_DIV_EXPR : RDIV_EXPR,
1660 const_binop (PLUS_EXPR,
1661 const_binop (MULT_EXPR, r1, r2,
1663 const_binop (MULT_EXPR, i1, i2,
1666 magsquared, notrunc),
1668 (INTEGRAL_TYPE_P (TREE_TYPE (r1))
1669 ? TRUNC_DIV_EXPR : RDIV_EXPR,
1670 const_binop (MINUS_EXPR,
1671 const_binop (MULT_EXPR, i1, r2,
1673 const_binop (MULT_EXPR, r1, i2,
1676 magsquared, notrunc));
1688 /* Return an INTEGER_CST with value V . The type is determined by bit_p:
1689 if it is zero, the type is taken from sizetype; if it is one, the type
1690 is taken from bitsizetype. */
1693 size_int_wide (number, high, bit_p)
1694 unsigned HOST_WIDE_INT number, high;
1701 /* Type-size nodes already made for small sizes. */
1702 static tree size_table[2*HOST_BITS_PER_WIDE_INT + 1][2];
1704 if (number < 2*HOST_BITS_PER_WIDE_INT + 1 && ! high
1705 && size_table[number][bit_p] != 0)
1706 return size_table[number][bit_p];
1707 if (number < 2*HOST_BITS_PER_WIDE_INT + 1 && ! high)
1709 push_obstacks_nochange ();
1710 /* Make this a permanent node. */
1711 end_temporary_allocation ();
1712 t = build_int_2 (number, 0);
1713 TREE_TYPE (t) = bit_p ? bitsizetype : sizetype;
1714 size_table[number][bit_p] = t;
1720 t = build_int_2 (number, high);
1721 TREE_TYPE (t) = bit_p ? bitsizetype : sizetype;
1722 TREE_OVERFLOW (t) = TREE_CONSTANT_OVERFLOW (t) = force_fit_type (t, 0);
1726 /* Combine operands OP1 and OP2 with arithmetic operation CODE.
1727 CODE is a tree code. Data type is taken from `sizetype',
1728 If the operands are constant, so is the result. */
1731 size_binop (code, arg0, arg1)
1732 enum tree_code code;
1735 /* Handle the special case of two integer constants faster. */
1736 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST)
1738 /* And some specific cases even faster than that. */
1739 if (code == PLUS_EXPR && integer_zerop (arg0))
1741 else if ((code == MINUS_EXPR || code == PLUS_EXPR)
1742 && integer_zerop (arg1))
1744 else if (code == MULT_EXPR && integer_onep (arg0))
1747 /* Handle general case of two integer constants. */
1748 return int_const_binop (code, arg0, arg1, 0, 1);
1751 if (arg0 == error_mark_node || arg1 == error_mark_node)
1752 return error_mark_node;
1754 return fold (build (code, sizetype, arg0, arg1));
1757 /* Combine operands OP1 and OP2 with arithmetic operation CODE.
1758 CODE is a tree code. Data type is taken from `ssizetype',
1759 If the operands are constant, so is the result. */
1762 ssize_binop (code, arg0, arg1)
1763 enum tree_code code;
1766 /* Handle the special case of two integer constants faster. */
1767 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST)
1769 /* And some specific cases even faster than that. */
1770 if (code == PLUS_EXPR && integer_zerop (arg0))
1772 else if ((code == MINUS_EXPR || code == PLUS_EXPR)
1773 && integer_zerop (arg1))
1775 else if (code == MULT_EXPR && integer_onep (arg0))
1778 /* Handle general case of two integer constants. We convert
1779 arg0 to ssizetype because int_const_binop uses its type for the
1781 arg0 = convert (ssizetype, arg0);
1782 return int_const_binop (code, arg0, arg1, 0, 0);
1785 if (arg0 == error_mark_node || arg1 == error_mark_node)
1786 return error_mark_node;
1788 return fold (build (code, ssizetype, arg0, arg1));
1800 fold_convert_1 (data)
1803 struct fc_args * args = (struct fc_args *) data;
1805 args->t = build_real (args->type,
1806 real_value_truncate (TYPE_MODE (args->type),
1807 TREE_REAL_CST (args->arg1)));
1810 /* Given T, a tree representing type conversion of ARG1, a constant,
1811 return a constant tree representing the result of conversion. */
1814 fold_convert (t, arg1)
1818 register tree type = TREE_TYPE (t);
1821 if (POINTER_TYPE_P (type) || INTEGRAL_TYPE_P (type))
1823 if (TREE_CODE (arg1) == INTEGER_CST)
1825 /* If we would build a constant wider than GCC supports,
1826 leave the conversion unfolded. */
1827 if (TYPE_PRECISION (type) > 2 * HOST_BITS_PER_WIDE_INT)
1830 /* Given an integer constant, make new constant with new type,
1831 appropriately sign-extended or truncated. */
1832 t = build_int_2 (TREE_INT_CST_LOW (arg1),
1833 TREE_INT_CST_HIGH (arg1));
1834 TREE_TYPE (t) = type;
1835 /* Indicate an overflow if (1) ARG1 already overflowed,
1836 or (2) force_fit_type indicates an overflow.
1837 Tell force_fit_type that an overflow has already occurred
1838 if ARG1 is a too-large unsigned value and T is signed.
1839 But don't indicate an overflow if converting a pointer. */
1841 = ((force_fit_type (t,
1842 (TREE_INT_CST_HIGH (arg1) < 0
1843 && (TREE_UNSIGNED (type)
1844 < TREE_UNSIGNED (TREE_TYPE (arg1)))))
1845 && ! POINTER_TYPE_P (TREE_TYPE (arg1)))
1846 || TREE_OVERFLOW (arg1));
1847 TREE_CONSTANT_OVERFLOW (t)
1848 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
1850 #if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
1851 else if (TREE_CODE (arg1) == REAL_CST)
1853 /* Don't initialize these, use assignments.
1854 Initialized local aggregates don't work on old compilers. */
1858 tree type1 = TREE_TYPE (arg1);
1861 x = TREE_REAL_CST (arg1);
1862 l = real_value_from_int_cst (type1, TYPE_MIN_VALUE (type));
1864 no_upper_bound = (TYPE_MAX_VALUE (type) == NULL);
1865 if (!no_upper_bound)
1866 u = real_value_from_int_cst (type1, TYPE_MAX_VALUE (type));
1868 /* See if X will be in range after truncation towards 0.
1869 To compensate for truncation, move the bounds away from 0,
1870 but reject if X exactly equals the adjusted bounds. */
1871 #ifdef REAL_ARITHMETIC
1872 REAL_ARITHMETIC (l, MINUS_EXPR, l, dconst1);
1873 if (!no_upper_bound)
1874 REAL_ARITHMETIC (u, PLUS_EXPR, u, dconst1);
1877 if (!no_upper_bound)
1880 /* If X is a NaN, use zero instead and show we have an overflow.
1881 Otherwise, range check. */
1882 if (REAL_VALUE_ISNAN (x))
1883 overflow = 1, x = dconst0;
1884 else if (! (REAL_VALUES_LESS (l, x)
1886 && REAL_VALUES_LESS (x, u)))
1889 #ifndef REAL_ARITHMETIC
1891 HOST_WIDE_INT low, high;
1892 HOST_WIDE_INT half_word
1893 = (HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2);
1898 high = (HOST_WIDE_INT) (x / half_word / half_word);
1899 x -= (REAL_VALUE_TYPE) high * half_word * half_word;
1900 if (x >= (REAL_VALUE_TYPE) half_word * half_word / 2)
1902 low = x - (REAL_VALUE_TYPE) half_word * half_word / 2;
1903 low |= (HOST_WIDE_INT) -1 << (HOST_BITS_PER_WIDE_INT - 1);
1906 low = (HOST_WIDE_INT) x;
1907 if (TREE_REAL_CST (arg1) < 0)
1908 neg_double (low, high, &low, &high);
1909 t = build_int_2 (low, high);
1913 HOST_WIDE_INT low, high;
1914 REAL_VALUE_TO_INT (&low, &high, x);
1915 t = build_int_2 (low, high);
1918 TREE_TYPE (t) = type;
1920 = TREE_OVERFLOW (arg1) | force_fit_type (t, overflow);
1921 TREE_CONSTANT_OVERFLOW (t)
1922 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
1924 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
1925 TREE_TYPE (t) = type;
1927 else if (TREE_CODE (type) == REAL_TYPE)
1929 #if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
1930 if (TREE_CODE (arg1) == INTEGER_CST)
1931 return build_real_from_int_cst (type, arg1);
1932 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
1933 if (TREE_CODE (arg1) == REAL_CST)
1935 struct fc_args args;
1937 if (REAL_VALUE_ISNAN (TREE_REAL_CST (arg1)))
1940 TREE_TYPE (arg1) = type;
1944 /* Setup input for fold_convert_1() */
1948 if (do_float_handler (fold_convert_1, (PTR) &args))
1950 /* Receive output from fold_convert_1() */
1955 /* We got an exception from fold_convert_1() */
1957 t = copy_node (arg1);
1961 = TREE_OVERFLOW (arg1) | force_fit_type (t, overflow);
1962 TREE_CONSTANT_OVERFLOW (t)
1963 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
1967 TREE_CONSTANT (t) = 1;
1971 /* Return an expr equal to X but certainly not valid as an lvalue. */
1979 /* These things are certainly not lvalues. */
1980 if (TREE_CODE (x) == NON_LVALUE_EXPR
1981 || TREE_CODE (x) == INTEGER_CST
1982 || TREE_CODE (x) == REAL_CST
1983 || TREE_CODE (x) == STRING_CST
1984 || TREE_CODE (x) == ADDR_EXPR)
1987 result = build1 (NON_LVALUE_EXPR, TREE_TYPE (x), x);
1988 TREE_CONSTANT (result) = TREE_CONSTANT (x);
1992 /* Nonzero means lvalues are limited to those valid in pedantic ANSI C.
1993 Zero means allow extended lvalues. */
1995 int pedantic_lvalues;
1997 /* When pedantic, return an expr equal to X but certainly not valid as a
1998 pedantic lvalue. Otherwise, return X. */
2001 pedantic_non_lvalue (x)
2004 if (pedantic_lvalues)
2005 return non_lvalue (x);
2010 /* Given a tree comparison code, return the code that is the logical inverse
2011 of the given code. It is not safe to do this for floating-point
2012 comparisons, except for NE_EXPR and EQ_EXPR. */
2014 static enum tree_code
2015 invert_tree_comparison (code)
2016 enum tree_code code;
2037 /* Similar, but return the comparison that results if the operands are
2038 swapped. This is safe for floating-point. */
2040 static enum tree_code
2041 swap_tree_comparison (code)
2042 enum tree_code code;
2062 /* Return nonzero if CODE is a tree code that represents a truth value. */
2065 truth_value_p (code)
2066 enum tree_code code;
2068 return (TREE_CODE_CLASS (code) == '<'
2069 || code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR
2070 || code == TRUTH_OR_EXPR || code == TRUTH_ORIF_EXPR
2071 || code == TRUTH_XOR_EXPR || code == TRUTH_NOT_EXPR);
2074 /* Return nonzero if two operands are necessarily equal.
2075 If ONLY_CONST is non-zero, only return non-zero for constants.
2076 This function tests whether the operands are indistinguishable;
2077 it does not test whether they are equal using C's == operation.
2078 The distinction is important for IEEE floating point, because
2079 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
2080 (2) two NaNs may be indistinguishable, but NaN!=NaN. */
2083 operand_equal_p (arg0, arg1, only_const)
2087 /* If both types don't have the same signedness, then we can't consider
2088 them equal. We must check this before the STRIP_NOPS calls
2089 because they may change the signedness of the arguments. */
2090 if (TREE_UNSIGNED (TREE_TYPE (arg0)) != TREE_UNSIGNED (TREE_TYPE (arg1)))
2096 if (TREE_CODE (arg0) != TREE_CODE (arg1)
2097 /* This is needed for conversions and for COMPONENT_REF.
2098 Might as well play it safe and always test this. */
2099 || TREE_CODE (TREE_TYPE (arg0)) == ERROR_MARK
2100 || TREE_CODE (TREE_TYPE (arg1)) == ERROR_MARK
2101 || TYPE_MODE (TREE_TYPE (arg0)) != TYPE_MODE (TREE_TYPE (arg1)))
2104 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
2105 We don't care about side effects in that case because the SAVE_EXPR
2106 takes care of that for us. In all other cases, two expressions are
2107 equal if they have no side effects. If we have two identical
2108 expressions with side effects that should be treated the same due
2109 to the only side effects being identical SAVE_EXPR's, that will
2110 be detected in the recursive calls below. */
2111 if (arg0 == arg1 && ! only_const
2112 && (TREE_CODE (arg0) == SAVE_EXPR
2113 || (! TREE_SIDE_EFFECTS (arg0) && ! TREE_SIDE_EFFECTS (arg1))))
2116 /* Next handle constant cases, those for which we can return 1 even
2117 if ONLY_CONST is set. */
2118 if (TREE_CONSTANT (arg0) && TREE_CONSTANT (arg1))
2119 switch (TREE_CODE (arg0))
2122 return (! TREE_CONSTANT_OVERFLOW (arg0)
2123 && ! TREE_CONSTANT_OVERFLOW (arg1)
2124 && TREE_INT_CST_LOW (arg0) == TREE_INT_CST_LOW (arg1)
2125 && TREE_INT_CST_HIGH (arg0) == TREE_INT_CST_HIGH (arg1));
2128 return (! TREE_CONSTANT_OVERFLOW (arg0)
2129 && ! TREE_CONSTANT_OVERFLOW (arg1)
2130 && REAL_VALUES_IDENTICAL (TREE_REAL_CST (arg0),
2131 TREE_REAL_CST (arg1)));
2134 return (operand_equal_p (TREE_REALPART (arg0), TREE_REALPART (arg1),
2136 && operand_equal_p (TREE_IMAGPART (arg0), TREE_IMAGPART (arg1),
2140 return (TREE_STRING_LENGTH (arg0) == TREE_STRING_LENGTH (arg1)
2141 && ! strncmp (TREE_STRING_POINTER (arg0),
2142 TREE_STRING_POINTER (arg1),
2143 TREE_STRING_LENGTH (arg0)));
2146 return operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0),
2155 switch (TREE_CODE_CLASS (TREE_CODE (arg0)))
2158 /* Two conversions are equal only if signedness and modes match. */
2159 if ((TREE_CODE (arg0) == NOP_EXPR || TREE_CODE (arg0) == CONVERT_EXPR)
2160 && (TREE_UNSIGNED (TREE_TYPE (arg0))
2161 != TREE_UNSIGNED (TREE_TYPE (arg1))))
2164 return operand_equal_p (TREE_OPERAND (arg0, 0),
2165 TREE_OPERAND (arg1, 0), 0);
2169 if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0), 0)
2170 && operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 1),
2174 /* For commutative ops, allow the other order. */
2175 return ((TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MULT_EXPR
2176 || TREE_CODE (arg0) == MIN_EXPR || TREE_CODE (arg0) == MAX_EXPR
2177 || TREE_CODE (arg0) == BIT_IOR_EXPR
2178 || TREE_CODE (arg0) == BIT_XOR_EXPR
2179 || TREE_CODE (arg0) == BIT_AND_EXPR
2180 || TREE_CODE (arg0) == NE_EXPR || TREE_CODE (arg0) == EQ_EXPR)
2181 && operand_equal_p (TREE_OPERAND (arg0, 0),
2182 TREE_OPERAND (arg1, 1), 0)
2183 && operand_equal_p (TREE_OPERAND (arg0, 1),
2184 TREE_OPERAND (arg1, 0), 0));
2187 /* If either of the pointer (or reference) expressions we are dereferencing
2188 contain a side effect, these cannot be equal. */
2189 if (TREE_SIDE_EFFECTS (arg0)
2190 || TREE_SIDE_EFFECTS (arg1))
2193 switch (TREE_CODE (arg0))
2196 return operand_equal_p (TREE_OPERAND (arg0, 0),
2197 TREE_OPERAND (arg1, 0), 0);
2201 return (operand_equal_p (TREE_OPERAND (arg0, 0),
2202 TREE_OPERAND (arg1, 0), 0)
2203 && operand_equal_p (TREE_OPERAND (arg0, 1),
2204 TREE_OPERAND (arg1, 1), 0));
2207 return (operand_equal_p (TREE_OPERAND (arg0, 0),
2208 TREE_OPERAND (arg1, 0), 0)
2209 && operand_equal_p (TREE_OPERAND (arg0, 1),
2210 TREE_OPERAND (arg1, 1), 0)
2211 && operand_equal_p (TREE_OPERAND (arg0, 2),
2212 TREE_OPERAND (arg1, 2), 0));
2218 if (TREE_CODE (arg0) == RTL_EXPR)
2219 return rtx_equal_p (RTL_EXPR_RTL (arg0), RTL_EXPR_RTL (arg1));
2227 /* Similar to operand_equal_p, but see if ARG0 might have been made by
2228 shorten_compare from ARG1 when ARG1 was being compared with OTHER.
2230 When in doubt, return 0. */
2233 operand_equal_for_comparison_p (arg0, arg1, other)
2237 int unsignedp1, unsignedpo;
2238 tree primarg0, primarg1, primother;
2239 unsigned correct_width;
2241 if (operand_equal_p (arg0, arg1, 0))
2244 if (! INTEGRAL_TYPE_P (TREE_TYPE (arg0))
2245 || ! INTEGRAL_TYPE_P (TREE_TYPE (arg1)))
2248 /* Discard any conversions that don't change the modes of ARG0 and ARG1
2249 and see if the inner values are the same. This removes any
2250 signedness comparison, which doesn't matter here. */
2251 primarg0 = arg0, primarg1 = arg1;
2252 STRIP_NOPS (primarg0); STRIP_NOPS (primarg1);
2253 if (operand_equal_p (primarg0, primarg1, 0))
2256 /* Duplicate what shorten_compare does to ARG1 and see if that gives the
2257 actual comparison operand, ARG0.
2259 First throw away any conversions to wider types
2260 already present in the operands. */
2262 primarg1 = get_narrower (arg1, &unsignedp1);
2263 primother = get_narrower (other, &unsignedpo);
2265 correct_width = TYPE_PRECISION (TREE_TYPE (arg1));
2266 if (unsignedp1 == unsignedpo
2267 && TYPE_PRECISION (TREE_TYPE (primarg1)) < correct_width
2268 && TYPE_PRECISION (TREE_TYPE (primother)) < correct_width)
2270 tree type = TREE_TYPE (arg0);
2272 /* Make sure shorter operand is extended the right way
2273 to match the longer operand. */
2274 primarg1 = convert (signed_or_unsigned_type (unsignedp1,
2275 TREE_TYPE (primarg1)),
2278 if (operand_equal_p (arg0, convert (type, primarg1), 0))
2285 /* See if ARG is an expression that is either a comparison or is performing
2286 arithmetic on comparisons. The comparisons must only be comparing
2287 two different values, which will be stored in *CVAL1 and *CVAL2; if
2288 they are non-zero it means that some operands have already been found.
2289 No variables may be used anywhere else in the expression except in the
2290 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
2291 the expression and save_expr needs to be called with CVAL1 and CVAL2.
2293 If this is true, return 1. Otherwise, return zero. */
2296 twoval_comparison_p (arg, cval1, cval2, save_p)
2298 tree *cval1, *cval2;
2301 enum tree_code code = TREE_CODE (arg);
2302 char class = TREE_CODE_CLASS (code);
2304 /* We can handle some of the 'e' cases here. */
2305 if (class == 'e' && code == TRUTH_NOT_EXPR)
2307 else if (class == 'e'
2308 && (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR
2309 || code == COMPOUND_EXPR))
2312 /* ??? Disable this since the SAVE_EXPR might already be in use outside
2313 the expression. There may be no way to make this work, but it needs
2314 to be looked at again for 2.6. */
2316 else if (class == 'e' && code == SAVE_EXPR && SAVE_EXPR_RTL (arg) == 0)
2318 /* If we've already found a CVAL1 or CVAL2, this expression is
2319 two complex to handle. */
2320 if (*cval1 || *cval2)
2331 return twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2, save_p);
2334 return (twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2, save_p)
2335 && twoval_comparison_p (TREE_OPERAND (arg, 1),
2336 cval1, cval2, save_p));
2342 if (code == COND_EXPR)
2343 return (twoval_comparison_p (TREE_OPERAND (arg, 0),
2344 cval1, cval2, save_p)
2345 && twoval_comparison_p (TREE_OPERAND (arg, 1),
2346 cval1, cval2, save_p)
2347 && twoval_comparison_p (TREE_OPERAND (arg, 2),
2348 cval1, cval2, save_p));
2352 /* First see if we can handle the first operand, then the second. For
2353 the second operand, we know *CVAL1 can't be zero. It must be that
2354 one side of the comparison is each of the values; test for the
2355 case where this isn't true by failing if the two operands
2358 if (operand_equal_p (TREE_OPERAND (arg, 0),
2359 TREE_OPERAND (arg, 1), 0))
2363 *cval1 = TREE_OPERAND (arg, 0);
2364 else if (operand_equal_p (*cval1, TREE_OPERAND (arg, 0), 0))
2366 else if (*cval2 == 0)
2367 *cval2 = TREE_OPERAND (arg, 0);
2368 else if (operand_equal_p (*cval2, TREE_OPERAND (arg, 0), 0))
2373 if (operand_equal_p (*cval1, TREE_OPERAND (arg, 1), 0))
2375 else if (*cval2 == 0)
2376 *cval2 = TREE_OPERAND (arg, 1);
2377 else if (operand_equal_p (*cval2, TREE_OPERAND (arg, 1), 0))
2389 /* ARG is a tree that is known to contain just arithmetic operations and
2390 comparisons. Evaluate the operations in the tree substituting NEW0 for
2391 any occurrence of OLD0 as an operand of a comparison and likewise for
2395 eval_subst (arg, old0, new0, old1, new1)
2397 tree old0, new0, old1, new1;
2399 tree type = TREE_TYPE (arg);
2400 enum tree_code code = TREE_CODE (arg);
2401 char class = TREE_CODE_CLASS (code);
2403 /* We can handle some of the 'e' cases here. */
2404 if (class == 'e' && code == TRUTH_NOT_EXPR)
2406 else if (class == 'e'
2407 && (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR))
2413 return fold (build1 (code, type,
2414 eval_subst (TREE_OPERAND (arg, 0),
2415 old0, new0, old1, new1)));
2418 return fold (build (code, type,
2419 eval_subst (TREE_OPERAND (arg, 0),
2420 old0, new0, old1, new1),
2421 eval_subst (TREE_OPERAND (arg, 1),
2422 old0, new0, old1, new1)));
2428 return eval_subst (TREE_OPERAND (arg, 0), old0, new0, old1, new1);
2431 return eval_subst (TREE_OPERAND (arg, 1), old0, new0, old1, new1);
2434 return fold (build (code, type,
2435 eval_subst (TREE_OPERAND (arg, 0),
2436 old0, new0, old1, new1),
2437 eval_subst (TREE_OPERAND (arg, 1),
2438 old0, new0, old1, new1),
2439 eval_subst (TREE_OPERAND (arg, 2),
2440 old0, new0, old1, new1)));
2444 /* fall through - ??? */
2448 tree arg0 = TREE_OPERAND (arg, 0);
2449 tree arg1 = TREE_OPERAND (arg, 1);
2451 /* We need to check both for exact equality and tree equality. The
2452 former will be true if the operand has a side-effect. In that
2453 case, we know the operand occurred exactly once. */
2455 if (arg0 == old0 || operand_equal_p (arg0, old0, 0))
2457 else if (arg0 == old1 || operand_equal_p (arg0, old1, 0))
2460 if (arg1 == old0 || operand_equal_p (arg1, old0, 0))
2462 else if (arg1 == old1 || operand_equal_p (arg1, old1, 0))
2465 return fold (build (code, type, arg0, arg1));
2473 /* Return a tree for the case when the result of an expression is RESULT
2474 converted to TYPE and OMITTED was previously an operand of the expression
2475 but is now not needed (e.g., we folded OMITTED * 0).
2477 If OMITTED has side effects, we must evaluate it. Otherwise, just do
2478 the conversion of RESULT to TYPE. */
2481 omit_one_operand (type, result, omitted)
2482 tree type, result, omitted;
2484 tree t = convert (type, result);
2486 if (TREE_SIDE_EFFECTS (omitted))
2487 return build (COMPOUND_EXPR, type, omitted, t);
2489 return non_lvalue (t);
2492 /* Similar, but call pedantic_non_lvalue instead of non_lvalue. */
2495 pedantic_omit_one_operand (type, result, omitted)
2496 tree type, result, omitted;
2498 tree t = convert (type, result);
2500 if (TREE_SIDE_EFFECTS (omitted))
2501 return build (COMPOUND_EXPR, type, omitted, t);
2503 return pedantic_non_lvalue (t);
2508 /* Return a simplified tree node for the truth-negation of ARG. This
2509 never alters ARG itself. We assume that ARG is an operation that
2510 returns a truth value (0 or 1). */
2513 invert_truthvalue (arg)
2516 tree type = TREE_TYPE (arg);
2517 enum tree_code code = TREE_CODE (arg);
2519 if (code == ERROR_MARK)
2522 /* If this is a comparison, we can simply invert it, except for
2523 floating-point non-equality comparisons, in which case we just
2524 enclose a TRUTH_NOT_EXPR around what we have. */
2526 if (TREE_CODE_CLASS (code) == '<')
2528 if (FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg, 0)))
2529 && !flag_fast_math && code != NE_EXPR && code != EQ_EXPR)
2530 return build1 (TRUTH_NOT_EXPR, type, arg);
2532 return build (invert_tree_comparison (code), type,
2533 TREE_OPERAND (arg, 0), TREE_OPERAND (arg, 1));
2539 return convert (type, build_int_2 (TREE_INT_CST_LOW (arg) == 0
2540 && TREE_INT_CST_HIGH (arg) == 0, 0));
2542 case TRUTH_AND_EXPR:
2543 return build (TRUTH_OR_EXPR, type,
2544 invert_truthvalue (TREE_OPERAND (arg, 0)),
2545 invert_truthvalue (TREE_OPERAND (arg, 1)));
2548 return build (TRUTH_AND_EXPR, type,
2549 invert_truthvalue (TREE_OPERAND (arg, 0)),
2550 invert_truthvalue (TREE_OPERAND (arg, 1)));
2552 case TRUTH_XOR_EXPR:
2553 /* Here we can invert either operand. We invert the first operand
2554 unless the second operand is a TRUTH_NOT_EXPR in which case our
2555 result is the XOR of the first operand with the inside of the
2556 negation of the second operand. */
2558 if (TREE_CODE (TREE_OPERAND (arg, 1)) == TRUTH_NOT_EXPR)
2559 return build (TRUTH_XOR_EXPR, type, TREE_OPERAND (arg, 0),
2560 TREE_OPERAND (TREE_OPERAND (arg, 1), 0));
2562 return build (TRUTH_XOR_EXPR, type,
2563 invert_truthvalue (TREE_OPERAND (arg, 0)),
2564 TREE_OPERAND (arg, 1));
2566 case TRUTH_ANDIF_EXPR:
2567 return build (TRUTH_ORIF_EXPR, type,
2568 invert_truthvalue (TREE_OPERAND (arg, 0)),
2569 invert_truthvalue (TREE_OPERAND (arg, 1)));
2571 case TRUTH_ORIF_EXPR:
2572 return build (TRUTH_ANDIF_EXPR, type,
2573 invert_truthvalue (TREE_OPERAND (arg, 0)),
2574 invert_truthvalue (TREE_OPERAND (arg, 1)));
2576 case TRUTH_NOT_EXPR:
2577 return TREE_OPERAND (arg, 0);
2580 return build (COND_EXPR, type, TREE_OPERAND (arg, 0),
2581 invert_truthvalue (TREE_OPERAND (arg, 1)),
2582 invert_truthvalue (TREE_OPERAND (arg, 2)));
2585 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg, 0),
2586 invert_truthvalue (TREE_OPERAND (arg, 1)));
2588 case NON_LVALUE_EXPR:
2589 return invert_truthvalue (TREE_OPERAND (arg, 0));
2594 return build1 (TREE_CODE (arg), type,
2595 invert_truthvalue (TREE_OPERAND (arg, 0)));
2598 if (!integer_onep (TREE_OPERAND (arg, 1)))
2600 return build (EQ_EXPR, type, arg, convert (type, integer_zero_node));
2603 return build1 (TRUTH_NOT_EXPR, type, arg);
2605 case CLEANUP_POINT_EXPR:
2606 return build1 (CLEANUP_POINT_EXPR, type,
2607 invert_truthvalue (TREE_OPERAND (arg, 0)));
2612 if (TREE_CODE (TREE_TYPE (arg)) != BOOLEAN_TYPE)
2614 return build1 (TRUTH_NOT_EXPR, type, arg);
2617 /* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both
2618 operands are another bit-wise operation with a common input. If so,
2619 distribute the bit operations to save an operation and possibly two if
2620 constants are involved. For example, convert
2621 (A | B) & (A | C) into A | (B & C)
2622 Further simplification will occur if B and C are constants.
2624 If this optimization cannot be done, 0 will be returned. */
2627 distribute_bit_expr (code, type, arg0, arg1)
2628 enum tree_code code;
2635 if (TREE_CODE (arg0) != TREE_CODE (arg1)
2636 || TREE_CODE (arg0) == code
2637 || (TREE_CODE (arg0) != BIT_AND_EXPR
2638 && TREE_CODE (arg0) != BIT_IOR_EXPR))
2641 if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0), 0))
2643 common = TREE_OPERAND (arg0, 0);
2644 left = TREE_OPERAND (arg0, 1);
2645 right = TREE_OPERAND (arg1, 1);
2647 else if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 1), 0))
2649 common = TREE_OPERAND (arg0, 0);
2650 left = TREE_OPERAND (arg0, 1);
2651 right = TREE_OPERAND (arg1, 0);
2653 else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 0), 0))
2655 common = TREE_OPERAND (arg0, 1);
2656 left = TREE_OPERAND (arg0, 0);
2657 right = TREE_OPERAND (arg1, 1);
2659 else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 1), 0))
2661 common = TREE_OPERAND (arg0, 1);
2662 left = TREE_OPERAND (arg0, 0);
2663 right = TREE_OPERAND (arg1, 0);
2668 return fold (build (TREE_CODE (arg0), type, common,
2669 fold (build (code, type, left, right))));
2672 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
2673 starting at BITPOS. The field is unsigned if UNSIGNEDP is non-zero. */
2676 make_bit_field_ref (inner, type, bitsize, bitpos, unsignedp)
2679 int bitsize, bitpos;
2682 tree result = build (BIT_FIELD_REF, type, inner,
2683 size_int (bitsize), bitsize_int (bitpos, 0L));
2685 TREE_UNSIGNED (result) = unsignedp;
2690 /* Optimize a bit-field compare.
2692 There are two cases: First is a compare against a constant and the
2693 second is a comparison of two items where the fields are at the same
2694 bit position relative to the start of a chunk (byte, halfword, word)
2695 large enough to contain it. In these cases we can avoid the shift
2696 implicit in bitfield extractions.
2698 For constants, we emit a compare of the shifted constant with the
2699 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
2700 compared. For two fields at the same position, we do the ANDs with the
2701 similar mask and compare the result of the ANDs.
2703 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
2704 COMPARE_TYPE is the type of the comparison, and LHS and RHS
2705 are the left and right operands of the comparison, respectively.
2707 If the optimization described above can be done, we return the resulting
2708 tree. Otherwise we return zero. */
2711 optimize_bit_field_compare (code, compare_type, lhs, rhs)
2712 enum tree_code code;
2716 int lbitpos, lbitsize, rbitpos, rbitsize;
2717 int lnbitpos, lnbitsize, rnbitpos = 0, rnbitsize = 0;
2718 tree type = TREE_TYPE (lhs);
2719 tree signed_type, unsigned_type;
2720 int const_p = TREE_CODE (rhs) == INTEGER_CST;
2721 enum machine_mode lmode, rmode, lnmode, rnmode = VOIDmode;
2722 int lunsignedp, runsignedp;
2723 int lvolatilep = 0, rvolatilep = 0;
2725 tree linner, rinner = NULL_TREE;
2729 /* Get all the information about the extractions being done. If the bit size
2730 if the same as the size of the underlying object, we aren't doing an
2731 extraction at all and so can do nothing. */
2732 linner = get_inner_reference (lhs, &lbitsize, &lbitpos, &offset, &lmode,
2733 &lunsignedp, &lvolatilep, &alignment);
2734 if (linner == lhs || lbitsize == GET_MODE_BITSIZE (lmode) || lbitsize < 0
2740 /* If this is not a constant, we can only do something if bit positions,
2741 sizes, and signedness are the same. */
2742 rinner = get_inner_reference (rhs, &rbitsize, &rbitpos, &offset, &rmode,
2743 &runsignedp, &rvolatilep, &alignment);
2745 if (rinner == rhs || lbitpos != rbitpos || lbitsize != rbitsize
2746 || lunsignedp != runsignedp || offset != 0)
2750 /* See if we can find a mode to refer to this field. We should be able to,
2751 but fail if we can't. */
2752 lnmode = get_best_mode (lbitsize, lbitpos,
2753 TYPE_ALIGN (TREE_TYPE (linner)), word_mode,
2755 if (lnmode == VOIDmode)
2758 /* Set signed and unsigned types of the precision of this mode for the
2760 signed_type = type_for_mode (lnmode, 0);
2761 unsigned_type = type_for_mode (lnmode, 1);
2765 rnmode = get_best_mode (rbitsize, rbitpos,
2766 TYPE_ALIGN (TREE_TYPE (rinner)), word_mode,
2768 if (rnmode == VOIDmode)
2772 /* Compute the bit position and size for the new reference and our offset
2773 within it. If the new reference is the same size as the original, we
2774 won't optimize anything, so return zero. */
2775 lnbitsize = GET_MODE_BITSIZE (lnmode);
2776 lnbitpos = lbitpos & ~ (lnbitsize - 1);
2777 lbitpos -= lnbitpos;
2778 if (lnbitsize == lbitsize)
2783 rnbitsize = GET_MODE_BITSIZE (rnmode);
2784 rnbitpos = rbitpos & ~ (rnbitsize - 1);
2785 rbitpos -= rnbitpos;
2786 if (rnbitsize == rbitsize)
2790 if (BYTES_BIG_ENDIAN)
2791 lbitpos = lnbitsize - lbitsize - lbitpos;
2793 /* Make the mask to be used against the extracted field. */
2794 mask = build_int_2 (~0, ~0);
2795 TREE_TYPE (mask) = unsigned_type;
2796 force_fit_type (mask, 0);
2797 mask = convert (unsigned_type, mask);
2798 mask = const_binop (LSHIFT_EXPR, mask, size_int (lnbitsize - lbitsize), 0);
2799 mask = const_binop (RSHIFT_EXPR, mask,
2800 size_int (lnbitsize - lbitsize - lbitpos), 0);
2803 /* If not comparing with constant, just rework the comparison
2805 return build (code, compare_type,
2806 build (BIT_AND_EXPR, unsigned_type,
2807 make_bit_field_ref (linner, unsigned_type,
2808 lnbitsize, lnbitpos, 1),
2810 build (BIT_AND_EXPR, unsigned_type,
2811 make_bit_field_ref (rinner, unsigned_type,
2812 rnbitsize, rnbitpos, 1),
2815 /* Otherwise, we are handling the constant case. See if the constant is too
2816 big for the field. Warn and return a tree of for 0 (false) if so. We do
2817 this not only for its own sake, but to avoid having to test for this
2818 error case below. If we didn't, we might generate wrong code.
2820 For unsigned fields, the constant shifted right by the field length should
2821 be all zero. For signed fields, the high-order bits should agree with
2826 if (! integer_zerop (const_binop (RSHIFT_EXPR,
2827 convert (unsigned_type, rhs),
2828 size_int (lbitsize), 0)))
2830 warning ("comparison is always %d due to width of bitfield",
2832 return convert (compare_type,
2834 ? integer_one_node : integer_zero_node));
2839 tree tem = const_binop (RSHIFT_EXPR, convert (signed_type, rhs),
2840 size_int (lbitsize - 1), 0);
2841 if (! integer_zerop (tem) && ! integer_all_onesp (tem))
2843 warning ("comparison is always %d due to width of bitfield",
2845 return convert (compare_type,
2847 ? integer_one_node : integer_zero_node));
2851 /* Single-bit compares should always be against zero. */
2852 if (lbitsize == 1 && ! integer_zerop (rhs))
2854 code = code == EQ_EXPR ? NE_EXPR : EQ_EXPR;
2855 rhs = convert (type, integer_zero_node);
2858 /* Make a new bitfield reference, shift the constant over the
2859 appropriate number of bits and mask it with the computed mask
2860 (in case this was a signed field). If we changed it, make a new one. */
2861 lhs = make_bit_field_ref (linner, unsigned_type, lnbitsize, lnbitpos, 1);
2864 TREE_SIDE_EFFECTS (lhs) = 1;
2865 TREE_THIS_VOLATILE (lhs) = 1;
2868 rhs = fold (const_binop (BIT_AND_EXPR,
2869 const_binop (LSHIFT_EXPR,
2870 convert (unsigned_type, rhs),
2871 size_int (lbitpos), 0),
2874 return build (code, compare_type,
2875 build (BIT_AND_EXPR, unsigned_type, lhs, mask),
2879 /* Subroutine for fold_truthop: decode a field reference.
2881 If EXP is a comparison reference, we return the innermost reference.
2883 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
2884 set to the starting bit number.
2886 If the innermost field can be completely contained in a mode-sized
2887 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
2889 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
2890 otherwise it is not changed.
2892 *PUNSIGNEDP is set to the signedness of the field.
2894 *PMASK is set to the mask used. This is either contained in a
2895 BIT_AND_EXPR or derived from the width of the field.
2897 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
2899 Return 0 if this is not a component reference or is one that we can't
2900 do anything with. */
2903 decode_field_reference (exp, pbitsize, pbitpos, pmode, punsignedp,
2904 pvolatilep, pmask, pand_mask)
2906 int *pbitsize, *pbitpos;
2907 enum machine_mode *pmode;
2908 int *punsignedp, *pvolatilep;
2913 tree mask, inner, offset;
2918 /* All the optimizations using this function assume integer fields.
2919 There are problems with FP fields since the type_for_size call
2920 below can fail for, e.g., XFmode. */
2921 if (! INTEGRAL_TYPE_P (TREE_TYPE (exp)))
2926 if (TREE_CODE (exp) == BIT_AND_EXPR)
2928 and_mask = TREE_OPERAND (exp, 1);
2929 exp = TREE_OPERAND (exp, 0);
2930 STRIP_NOPS (exp); STRIP_NOPS (and_mask);
2931 if (TREE_CODE (and_mask) != INTEGER_CST)
2936 inner = get_inner_reference (exp, pbitsize, pbitpos, &offset, pmode,
2937 punsignedp, pvolatilep, &alignment);
2938 if ((inner == exp && and_mask == 0)
2939 || *pbitsize < 0 || offset != 0)
2942 /* Compute the mask to access the bitfield. */
2943 unsigned_type = type_for_size (*pbitsize, 1);
2944 precision = TYPE_PRECISION (unsigned_type);
2946 mask = build_int_2 (~0, ~0);
2947 TREE_TYPE (mask) = unsigned_type;
2948 force_fit_type (mask, 0);
2949 mask = const_binop (LSHIFT_EXPR, mask, size_int (precision - *pbitsize), 0);
2950 mask = const_binop (RSHIFT_EXPR, mask, size_int (precision - *pbitsize), 0);
2952 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
2954 mask = fold (build (BIT_AND_EXPR, unsigned_type,
2955 convert (unsigned_type, and_mask), mask));
2958 *pand_mask = and_mask;
2962 /* Return non-zero if MASK represents a mask of SIZE ones in the low-order
2966 all_ones_mask_p (mask, size)
2970 tree type = TREE_TYPE (mask);
2971 int precision = TYPE_PRECISION (type);
2974 tmask = build_int_2 (~0, ~0);
2975 TREE_TYPE (tmask) = signed_type (type);
2976 force_fit_type (tmask, 0);
2978 tree_int_cst_equal (mask,
2979 const_binop (RSHIFT_EXPR,
2980 const_binop (LSHIFT_EXPR, tmask,
2981 size_int (precision - size),
2983 size_int (precision - size), 0));
2986 /* Subroutine for fold_truthop: determine if an operand is simple enough
2987 to be evaluated unconditionally. */
2990 simple_operand_p (exp)
2993 /* Strip any conversions that don't change the machine mode. */
2994 while ((TREE_CODE (exp) == NOP_EXPR
2995 || TREE_CODE (exp) == CONVERT_EXPR)
2996 && (TYPE_MODE (TREE_TYPE (exp))
2997 == TYPE_MODE (TREE_TYPE (TREE_OPERAND (exp, 0)))))
2998 exp = TREE_OPERAND (exp, 0);
3000 return (TREE_CODE_CLASS (TREE_CODE (exp)) == 'c'
3001 || (TREE_CODE_CLASS (TREE_CODE (exp)) == 'd'
3002 && ! TREE_ADDRESSABLE (exp)
3003 && ! TREE_THIS_VOLATILE (exp)
3004 && ! DECL_NONLOCAL (exp)
3005 /* Don't regard global variables as simple. They may be
3006 allocated in ways unknown to the compiler (shared memory,
3007 #pragma weak, etc). */
3008 && ! TREE_PUBLIC (exp)
3009 && ! DECL_EXTERNAL (exp)
3010 /* Loading a static variable is unduly expensive, but global
3011 registers aren't expensive. */
3012 && (! TREE_STATIC (exp) || DECL_REGISTER (exp))));
3015 /* The following functions are subroutines to fold_range_test and allow it to
3016 try to change a logical combination of comparisons into a range test.
3019 X == 2 && X == 3 && X == 4 && X == 5
3023 (unsigned) (X - 2) <= 3
3025 We describe each set of comparisons as being either inside or outside
3026 a range, using a variable named like IN_P, and then describe the
3027 range with a lower and upper bound. If one of the bounds is omitted,
3028 it represents either the highest or lowest value of the type.
3030 In the comments below, we represent a range by two numbers in brackets
3031 preceded by a "+" to designate being inside that range, or a "-" to
3032 designate being outside that range, so the condition can be inverted by
3033 flipping the prefix. An omitted bound is represented by a "-". For
3034 example, "- [-, 10]" means being outside the range starting at the lowest
3035 possible value and ending at 10, in other words, being greater than 10.
3036 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
3039 We set up things so that the missing bounds are handled in a consistent
3040 manner so neither a missing bound nor "true" and "false" need to be
3041 handled using a special case. */
3043 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
3044 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
3045 and UPPER1_P are nonzero if the respective argument is an upper bound
3046 and zero for a lower. TYPE, if nonzero, is the type of the result; it
3047 must be specified for a comparison. ARG1 will be converted to ARG0's
3048 type if both are specified. */
3051 range_binop (code, type, arg0, upper0_p, arg1, upper1_p)
3052 enum tree_code code;
3055 int upper0_p, upper1_p;
3061 /* If neither arg represents infinity, do the normal operation.
3062 Else, if not a comparison, return infinity. Else handle the special
3063 comparison rules. Note that most of the cases below won't occur, but
3064 are handled for consistency. */
3066 if (arg0 != 0 && arg1 != 0)
3068 tem = fold (build (code, type != 0 ? type : TREE_TYPE (arg0),
3069 arg0, convert (TREE_TYPE (arg0), arg1)));
3071 return TREE_CODE (tem) == INTEGER_CST ? tem : 0;
3074 if (TREE_CODE_CLASS (code) != '<')
3077 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
3078 for neither. In real maths, we cannot assume open ended ranges are
3079 the same. But, this is computer arithmetic, where numbers are finite.
3080 We can therefore make the transformation of any unbounded range with
3081 the value Z, Z being greater than any representable number. This permits
3082 us to treat unbounded ranges as equal. */
3083 sgn0 = arg0 != 0 ? 0 : (upper0_p ? 1 : -1);
3084 sgn1 = arg1 != 0 ? 0 : (upper1_p ? 1 : -1);
3088 result = sgn0 == sgn1;
3091 result = sgn0 != sgn1;
3094 result = sgn0 < sgn1;
3097 result = sgn0 <= sgn1;
3100 result = sgn0 > sgn1;
3103 result = sgn0 >= sgn1;
3109 return convert (type, result ? integer_one_node : integer_zero_node);
3112 /* Given EXP, a logical expression, set the range it is testing into
3113 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
3114 actually being tested. *PLOW and *PHIGH will have be made the same type
3115 as the returned expression. If EXP is not a comparison, we will most
3116 likely not be returning a useful value and range. */
3119 make_range (exp, pin_p, plow, phigh)
3124 enum tree_code code;
3125 tree arg0 = NULL_TREE, arg1 = NULL_TREE, type = NULL_TREE;
3126 tree orig_type = NULL_TREE;
3128 tree low, high, n_low, n_high;
3130 /* Start with simply saying "EXP != 0" and then look at the code of EXP
3131 and see if we can refine the range. Some of the cases below may not
3132 happen, but it doesn't seem worth worrying about this. We "continue"
3133 the outer loop when we've changed something; otherwise we "break"
3134 the switch, which will "break" the while. */
3136 in_p = 0, low = high = convert (TREE_TYPE (exp), integer_zero_node);
3140 code = TREE_CODE (exp);
3142 if (IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (code)))
3144 arg0 = TREE_OPERAND (exp, 0);
3145 if (TREE_CODE_CLASS (code) == '<'
3146 || TREE_CODE_CLASS (code) == '1'
3147 || TREE_CODE_CLASS (code) == '2')
3148 type = TREE_TYPE (arg0);
3149 if (TREE_CODE_CLASS (code) == '2'
3150 || TREE_CODE_CLASS (code) == '<'
3151 || (TREE_CODE_CLASS (code) == 'e'
3152 && tree_code_length[(int) code] > 1))
3153 arg1 = TREE_OPERAND (exp, 1);
3156 /* Set ORIG_TYPE as soon as TYPE is non-null so that we do not
3157 lose a cast by accident. */
3158 if (type != NULL_TREE && orig_type == NULL_TREE)
3163 case TRUTH_NOT_EXPR:
3164 in_p = ! in_p, exp = arg0;
3167 case EQ_EXPR: case NE_EXPR:
3168 case LT_EXPR: case LE_EXPR: case GE_EXPR: case GT_EXPR:
3169 /* We can only do something if the range is testing for zero
3170 and if the second operand is an integer constant. Note that
3171 saying something is "in" the range we make is done by
3172 complementing IN_P since it will set in the initial case of
3173 being not equal to zero; "out" is leaving it alone. */
3174 if (low == 0 || high == 0
3175 || ! integer_zerop (low) || ! integer_zerop (high)
3176 || TREE_CODE (arg1) != INTEGER_CST)
3181 case NE_EXPR: /* - [c, c] */
3184 case EQ_EXPR: /* + [c, c] */
3185 in_p = ! in_p, low = high = arg1;
3187 case GT_EXPR: /* - [-, c] */
3188 low = 0, high = arg1;
3190 case GE_EXPR: /* + [c, -] */
3191 in_p = ! in_p, low = arg1, high = 0;
3193 case LT_EXPR: /* - [c, -] */
3194 low = arg1, high = 0;
3196 case LE_EXPR: /* + [-, c] */
3197 in_p = ! in_p, low = 0, high = arg1;
3205 /* If this is an unsigned comparison, we also know that EXP is
3206 greater than or equal to zero. We base the range tests we make
3207 on that fact, so we record it here so we can parse existing
3209 if (TREE_UNSIGNED (type) && (low == 0 || high == 0))
3211 if (! merge_ranges (&n_in_p, &n_low, &n_high, in_p, low, high,
3212 1, convert (type, integer_zero_node),
3216 in_p = n_in_p, low = n_low, high = n_high;
3218 /* If the high bound is missing, reverse the range so it
3219 goes from zero to the low bound minus 1. */
3223 high = range_binop (MINUS_EXPR, NULL_TREE, low, 0,
3224 integer_one_node, 0);
3225 low = convert (type, integer_zero_node);
3231 /* (-x) IN [a,b] -> x in [-b, -a] */
3232 n_low = range_binop (MINUS_EXPR, type,
3233 convert (type, integer_zero_node), 0, high, 1);
3234 n_high = range_binop (MINUS_EXPR, type,
3235 convert (type, integer_zero_node), 0, low, 0);
3236 low = n_low, high = n_high;
3242 exp = build (MINUS_EXPR, type, build1 (NEGATE_EXPR, type, arg0),
3243 convert (type, integer_one_node));
3246 case PLUS_EXPR: case MINUS_EXPR:
3247 if (TREE_CODE (arg1) != INTEGER_CST)
3250 /* If EXP is signed, any overflow in the computation is undefined,
3251 so we don't worry about it so long as our computations on
3252 the bounds don't overflow. For unsigned, overflow is defined
3253 and this is exactly the right thing. */
3254 n_low = range_binop (code == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR,
3255 type, low, 0, arg1, 0);
3256 n_high = range_binop (code == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR,
3257 type, high, 1, arg1, 0);
3258 if ((n_low != 0 && TREE_OVERFLOW (n_low))
3259 || (n_high != 0 && TREE_OVERFLOW (n_high)))
3262 /* Check for an unsigned range which has wrapped around the maximum
3263 value thus making n_high < n_low, and normalize it. */
3264 if (n_low && n_high && tree_int_cst_lt (n_high, n_low))
3266 low = range_binop (PLUS_EXPR, type, n_high, 0,
3267 integer_one_node, 0);
3268 high = range_binop (MINUS_EXPR, type, n_low, 0,
3269 integer_one_node, 0);
3273 low = n_low, high = n_high;
3278 case NOP_EXPR: case NON_LVALUE_EXPR: case CONVERT_EXPR:
3279 if (TYPE_PRECISION (type) > TYPE_PRECISION (orig_type))
3282 if (! INTEGRAL_TYPE_P (type)
3283 || (low != 0 && ! int_fits_type_p (low, type))
3284 || (high != 0 && ! int_fits_type_p (high, type)))
3287 n_low = low, n_high = high;
3290 n_low = convert (type, n_low);
3293 n_high = convert (type, n_high);
3295 /* If we're converting from an unsigned to a signed type,
3296 we will be doing the comparison as unsigned. The tests above
3297 have already verified that LOW and HIGH are both positive.
3299 So we have to make sure that the original unsigned value will
3300 be interpreted as positive. */
3301 if (TREE_UNSIGNED (type) && ! TREE_UNSIGNED (TREE_TYPE (exp)))
3303 tree equiv_type = type_for_mode (TYPE_MODE (type), 1);
3306 /* A range without an upper bound is, naturally, unbounded.
3307 Since convert would have cropped a very large value, use
3308 the max value for the destination type. */
3310 high_positive = TYPE_MAX_VALUE (equiv_type);
3313 high_positive = TYPE_MAX_VALUE (type);
3317 high_positive = fold (build (RSHIFT_EXPR, type,
3318 convert (type, high_positive),
3319 convert (type, integer_one_node)));
3321 /* If the low bound is specified, "and" the range with the
3322 range for which the original unsigned value will be
3326 if (! merge_ranges (&n_in_p, &n_low, &n_high,
3328 1, convert (type, integer_zero_node),
3332 in_p = (n_in_p == in_p);
3336 /* Otherwise, "or" the range with the range of the input
3337 that will be interpreted as negative. */
3338 if (! merge_ranges (&n_in_p, &n_low, &n_high,
3340 1, convert (type, integer_zero_node),
3344 in_p = (in_p != n_in_p);
3349 low = n_low, high = n_high;
3359 /* If EXP is a constant, we can evaluate whether this is true or false. */
3360 if (TREE_CODE (exp) == INTEGER_CST)
3362 in_p = in_p == (integer_onep (range_binop (GE_EXPR, integer_type_node,
3364 && integer_onep (range_binop (LE_EXPR, integer_type_node,
3370 *pin_p = in_p, *plow = low, *phigh = high;
3374 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
3375 type, TYPE, return an expression to test if EXP is in (or out of, depending
3376 on IN_P) the range. */
3379 build_range_check (type, exp, in_p, low, high)
3385 tree etype = TREE_TYPE (exp);
3389 && (0 != (value = build_range_check (type, exp, 1, low, high))))
3390 return invert_truthvalue (value);
3392 else if (low == 0 && high == 0)
3393 return convert (type, integer_one_node);
3396 return fold (build (LE_EXPR, type, exp, high));
3399 return fold (build (GE_EXPR, type, exp, low));
3401 else if (operand_equal_p (low, high, 0))
3402 return fold (build (EQ_EXPR, type, exp, low));
3404 else if (TREE_UNSIGNED (etype) && integer_zerop (low))
3405 return build_range_check (type, exp, 1, 0, high);
3407 else if (integer_zerop (low))
3409 utype = unsigned_type (etype);
3410 return build_range_check (type, convert (utype, exp), 1, 0,
3411 convert (utype, high));
3414 else if (0 != (value = const_binop (MINUS_EXPR, high, low, 0))
3415 && ! TREE_OVERFLOW (value))
3416 return build_range_check (type,
3417 fold (build (MINUS_EXPR, etype, exp, low)),
3418 1, convert (etype, integer_zero_node), value);
3423 /* Given two ranges, see if we can merge them into one. Return 1 if we
3424 can, 0 if we can't. Set the output range into the specified parameters. */
3427 merge_ranges (pin_p, plow, phigh, in0_p, low0, high0, in1_p, low1, high1)
3431 tree low0, high0, low1, high1;
3439 int lowequal = ((low0 == 0 && low1 == 0)
3440 || integer_onep (range_binop (EQ_EXPR, integer_type_node,
3441 low0, 0, low1, 0)));
3442 int highequal = ((high0 == 0 && high1 == 0)
3443 || integer_onep (range_binop (EQ_EXPR, integer_type_node,
3444 high0, 1, high1, 1)));
3446 /* Make range 0 be the range that starts first, or ends last if they
3447 start at the same value. Swap them if it isn't. */
3448 if (integer_onep (range_binop (GT_EXPR, integer_type_node,
3451 && integer_onep (range_binop (GT_EXPR, integer_type_node,
3452 high1, 1, high0, 1))))
3454 temp = in0_p, in0_p = in1_p, in1_p = temp;
3455 tem = low0, low0 = low1, low1 = tem;
3456 tem = high0, high0 = high1, high1 = tem;
3459 /* Now flag two cases, whether the ranges are disjoint or whether the
3460 second range is totally subsumed in the first. Note that the tests
3461 below are simplified by the ones above. */
3462 no_overlap = integer_onep (range_binop (LT_EXPR, integer_type_node,
3463 high0, 1, low1, 0));
3464 subset = integer_onep (range_binop (LE_EXPR, integer_type_node,
3465 high1, 1, high0, 1));
3467 /* We now have four cases, depending on whether we are including or
3468 excluding the two ranges. */
3471 /* If they don't overlap, the result is false. If the second range
3472 is a subset it is the result. Otherwise, the range is from the start
3473 of the second to the end of the first. */
3475 in_p = 0, low = high = 0;
3477 in_p = 1, low = low1, high = high1;
3479 in_p = 1, low = low1, high = high0;
3482 else if (in0_p && ! in1_p)
3484 /* If they don't overlap, the result is the first range. If they are
3485 equal, the result is false. If the second range is a subset of the
3486 first, and the ranges begin at the same place, we go from just after
3487 the end of the first range to the end of the second. If the second
3488 range is not a subset of the first, or if it is a subset and both
3489 ranges end at the same place, the range starts at the start of the
3490 first range and ends just before the second range.
3491 Otherwise, we can't describe this as a single range. */
3493 in_p = 1, low = low0, high = high0;
3494 else if (lowequal && highequal)
3495 in_p = 0, low = high = 0;
3496 else if (subset && lowequal)
3498 in_p = 1, high = high0;
3499 low = range_binop (PLUS_EXPR, NULL_TREE, high1, 0,
3500 integer_one_node, 0);
3502 else if (! subset || highequal)
3504 in_p = 1, low = low0;
3505 high = range_binop (MINUS_EXPR, NULL_TREE, low1, 0,
3506 integer_one_node, 0);
3512 else if (! in0_p && in1_p)
3514 /* If they don't overlap, the result is the second range. If the second
3515 is a subset of the first, the result is false. Otherwise,
3516 the range starts just after the first range and ends at the
3517 end of the second. */
3519 in_p = 1, low = low1, high = high1;
3521 in_p = 0, low = high = 0;
3524 in_p = 1, high = high1;
3525 low = range_binop (PLUS_EXPR, NULL_TREE, high0, 1,
3526 integer_one_node, 0);
3532 /* The case where we are excluding both ranges. Here the complex case
3533 is if they don't overlap. In that case, the only time we have a
3534 range is if they are adjacent. If the second is a subset of the
3535 first, the result is the first. Otherwise, the range to exclude
3536 starts at the beginning of the first range and ends at the end of the
3540 if (integer_onep (range_binop (EQ_EXPR, integer_type_node,
3541 range_binop (PLUS_EXPR, NULL_TREE,
3543 integer_one_node, 1),
3545 in_p = 0, low = low0, high = high1;
3550 in_p = 0, low = low0, high = high0;
3552 in_p = 0, low = low0, high = high1;
3555 *pin_p = in_p, *plow = low, *phigh = high;
3559 /* EXP is some logical combination of boolean tests. See if we can
3560 merge it into some range test. Return the new tree if so. */
3563 fold_range_test (exp)
3566 int or_op = (TREE_CODE (exp) == TRUTH_ORIF_EXPR
3567 || TREE_CODE (exp) == TRUTH_OR_EXPR);
3568 int in0_p, in1_p, in_p;
3569 tree low0, low1, low, high0, high1, high;
3570 tree lhs = make_range (TREE_OPERAND (exp, 0), &in0_p, &low0, &high0);
3571 tree rhs = make_range (TREE_OPERAND (exp, 1), &in1_p, &low1, &high1);
3574 /* If this is an OR operation, invert both sides; we will invert
3575 again at the end. */
3577 in0_p = ! in0_p, in1_p = ! in1_p;
3579 /* If both expressions are the same, if we can merge the ranges, and we
3580 can build the range test, return it or it inverted. If one of the
3581 ranges is always true or always false, consider it to be the same
3582 expression as the other. */
3583 if ((lhs == 0 || rhs == 0 || operand_equal_p (lhs, rhs, 0))
3584 && merge_ranges (&in_p, &low, &high, in0_p, low0, high0,
3586 && 0 != (tem = (build_range_check (TREE_TYPE (exp),
3588 : rhs != 0 ? rhs : integer_zero_node,
3590 return or_op ? invert_truthvalue (tem) : tem;
3592 /* On machines where the branch cost is expensive, if this is a
3593 short-circuited branch and the underlying object on both sides
3594 is the same, make a non-short-circuit operation. */
3595 else if (BRANCH_COST >= 2
3596 && (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
3597 || TREE_CODE (exp) == TRUTH_ORIF_EXPR)
3598 && operand_equal_p (lhs, rhs, 0))
3600 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
3601 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
3602 which cases we can't do this. */
3603 if (simple_operand_p (lhs))
3604 return build (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
3605 ? TRUTH_AND_EXPR : TRUTH_OR_EXPR,
3606 TREE_TYPE (exp), TREE_OPERAND (exp, 0),
3607 TREE_OPERAND (exp, 1));
3609 else if (global_bindings_p () == 0
3610 && ! contains_placeholder_p (lhs))
3612 tree common = save_expr (lhs);
3614 if (0 != (lhs = build_range_check (TREE_TYPE (exp), common,
3615 or_op ? ! in0_p : in0_p,
3617 && (0 != (rhs = build_range_check (TREE_TYPE (exp), common,
3618 or_op ? ! in1_p : in1_p,
3620 return build (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
3621 ? TRUTH_AND_EXPR : TRUTH_OR_EXPR,
3622 TREE_TYPE (exp), lhs, rhs);
3629 /* Subroutine for fold_truthop: C is an INTEGER_CST interpreted as a P
3630 bit value. Arrange things so the extra bits will be set to zero if and
3631 only if C is signed-extended to its full width. If MASK is nonzero,
3632 it is an INTEGER_CST that should be AND'ed with the extra bits. */
3635 unextend (c, p, unsignedp, mask)
3641 tree type = TREE_TYPE (c);
3642 int modesize = GET_MODE_BITSIZE (TYPE_MODE (type));
3645 if (p == modesize || unsignedp)
3648 /* We work by getting just the sign bit into the low-order bit, then
3649 into the high-order bit, then sign-extend. We then XOR that value
3651 temp = const_binop (RSHIFT_EXPR, c, size_int (p - 1), 0);
3652 temp = const_binop (BIT_AND_EXPR, temp, size_int (1), 0);
3654 /* We must use a signed type in order to get an arithmetic right shift.
3655 However, we must also avoid introducing accidental overflows, so that
3656 a subsequent call to integer_zerop will work. Hence we must
3657 do the type conversion here. At this point, the constant is either
3658 zero or one, and the conversion to a signed type can never overflow.
3659 We could get an overflow if this conversion is done anywhere else. */
3660 if (TREE_UNSIGNED (type))
3661 temp = convert (signed_type (type), temp);
3663 temp = const_binop (LSHIFT_EXPR, temp, size_int (modesize - 1), 0);
3664 temp = const_binop (RSHIFT_EXPR, temp, size_int (modesize - p - 1), 0);
3666 temp = const_binop (BIT_AND_EXPR, temp, convert (TREE_TYPE (c), mask), 0);
3667 /* If necessary, convert the type back to match the type of C. */
3668 if (TREE_UNSIGNED (type))
3669 temp = convert (type, temp);
3671 return convert (type, const_binop (BIT_XOR_EXPR, c, temp, 0));
3674 /* Find ways of folding logical expressions of LHS and RHS:
3675 Try to merge two comparisons to the same innermost item.
3676 Look for range tests like "ch >= '0' && ch <= '9'".
3677 Look for combinations of simple terms on machines with expensive branches
3678 and evaluate the RHS unconditionally.
3680 For example, if we have p->a == 2 && p->b == 4 and we can make an
3681 object large enough to span both A and B, we can do this with a comparison
3682 against the object ANDed with the a mask.
3684 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
3685 operations to do this with one comparison.
3687 We check for both normal comparisons and the BIT_AND_EXPRs made this by
3688 function and the one above.
3690 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
3691 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
3693 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
3696 We return the simplified tree or 0 if no optimization is possible. */
3699 fold_truthop (code, truth_type, lhs, rhs)
3700 enum tree_code code;
3701 tree truth_type, lhs, rhs;
3703 /* If this is the "or" of two comparisons, we can do something if we
3704 the comparisons are NE_EXPR. If this is the "and", we can do something
3705 if the comparisons are EQ_EXPR. I.e.,
3706 (a->b == 2 && a->c == 4) can become (a->new == NEW).
3708 WANTED_CODE is this operation code. For single bit fields, we can
3709 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
3710 comparison for one-bit fields. */
3712 enum tree_code wanted_code;
3713 enum tree_code lcode, rcode;
3714 tree ll_arg, lr_arg, rl_arg, rr_arg;
3715 tree ll_inner, lr_inner, rl_inner, rr_inner;
3716 int ll_bitsize, ll_bitpos, lr_bitsize, lr_bitpos;
3717 int rl_bitsize, rl_bitpos, rr_bitsize, rr_bitpos;
3718 int xll_bitpos, xlr_bitpos, xrl_bitpos, xrr_bitpos;
3719 int lnbitsize, lnbitpos, rnbitsize, rnbitpos;
3720 int ll_unsignedp, lr_unsignedp, rl_unsignedp, rr_unsignedp;
3721 enum machine_mode ll_mode, lr_mode, rl_mode, rr_mode;
3722 enum machine_mode lnmode, rnmode;
3723 tree ll_mask, lr_mask, rl_mask, rr_mask;
3724 tree ll_and_mask, lr_and_mask, rl_and_mask, rr_and_mask;
3725 tree l_const, r_const;
3726 tree lntype, rntype, result;
3727 int first_bit, end_bit;
3730 /* Start by getting the comparison codes. Fail if anything is volatile.
3731 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
3732 it were surrounded with a NE_EXPR. */
3734 if (TREE_SIDE_EFFECTS (lhs) || TREE_SIDE_EFFECTS (rhs))
3737 lcode = TREE_CODE (lhs);
3738 rcode = TREE_CODE (rhs);
3740 if (lcode == BIT_AND_EXPR && integer_onep (TREE_OPERAND (lhs, 1)))
3741 lcode = NE_EXPR, lhs = build (NE_EXPR, truth_type, lhs, integer_zero_node);
3743 if (rcode == BIT_AND_EXPR && integer_onep (TREE_OPERAND (rhs, 1)))
3744 rcode = NE_EXPR, rhs = build (NE_EXPR, truth_type, rhs, integer_zero_node);
3746 if (TREE_CODE_CLASS (lcode) != '<' || TREE_CODE_CLASS (rcode) != '<')
3749 code = ((code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR)
3750 ? TRUTH_AND_EXPR : TRUTH_OR_EXPR);
3752 ll_arg = TREE_OPERAND (lhs, 0);
3753 lr_arg = TREE_OPERAND (lhs, 1);
3754 rl_arg = TREE_OPERAND (rhs, 0);
3755 rr_arg = TREE_OPERAND (rhs, 1);
3757 /* If the RHS can be evaluated unconditionally and its operands are
3758 simple, it wins to evaluate the RHS unconditionally on machines
3759 with expensive branches. In this case, this isn't a comparison
3760 that can be merged. */
3762 /* @@ I'm not sure it wins on the m88110 to do this if the comparisons
3763 are with zero (tmw). */
3765 if (BRANCH_COST >= 2
3766 && INTEGRAL_TYPE_P (TREE_TYPE (rhs))
3767 && simple_operand_p (rl_arg)
3768 && simple_operand_p (rr_arg))
3769 return build (code, truth_type, lhs, rhs);
3771 /* See if the comparisons can be merged. Then get all the parameters for
3774 if ((lcode != EQ_EXPR && lcode != NE_EXPR)
3775 || (rcode != EQ_EXPR && rcode != NE_EXPR))
3779 ll_inner = decode_field_reference (ll_arg,
3780 &ll_bitsize, &ll_bitpos, &ll_mode,
3781 &ll_unsignedp, &volatilep, &ll_mask,
3783 lr_inner = decode_field_reference (lr_arg,
3784 &lr_bitsize, &lr_bitpos, &lr_mode,
3785 &lr_unsignedp, &volatilep, &lr_mask,
3787 rl_inner = decode_field_reference (rl_arg,
3788 &rl_bitsize, &rl_bitpos, &rl_mode,
3789 &rl_unsignedp, &volatilep, &rl_mask,
3791 rr_inner = decode_field_reference (rr_arg,
3792 &rr_bitsize, &rr_bitpos, &rr_mode,
3793 &rr_unsignedp, &volatilep, &rr_mask,
3796 /* It must be true that the inner operation on the lhs of each
3797 comparison must be the same if we are to be able to do anything.
3798 Then see if we have constants. If not, the same must be true for
3800 if (volatilep || ll_inner == 0 || rl_inner == 0
3801 || ! operand_equal_p (ll_inner, rl_inner, 0))
3804 if (TREE_CODE (lr_arg) == INTEGER_CST
3805 && TREE_CODE (rr_arg) == INTEGER_CST)
3806 l_const = lr_arg, r_const = rr_arg;
3807 else if (lr_inner == 0 || rr_inner == 0
3808 || ! operand_equal_p (lr_inner, rr_inner, 0))
3811 l_const = r_const = 0;
3813 /* If either comparison code is not correct for our logical operation,
3814 fail. However, we can convert a one-bit comparison against zero into
3815 the opposite comparison against that bit being set in the field. */
3817 wanted_code = (code == TRUTH_AND_EXPR ? EQ_EXPR : NE_EXPR);
3818 if (lcode != wanted_code)
3820 if (l_const && integer_zerop (l_const) && integer_pow2p (ll_mask))
3822 /* Make the left operand unsigned, since we are only interested
3823 in the value of one bit. Otherwise we are doing the wrong
3832 /* This is analogous to the code for l_const above. */
3833 if (rcode != wanted_code)
3835 if (r_const && integer_zerop (r_const) && integer_pow2p (rl_mask))
3844 /* See if we can find a mode that contains both fields being compared on
3845 the left. If we can't, fail. Otherwise, update all constants and masks
3846 to be relative to a field of that size. */
3847 first_bit = MIN (ll_bitpos, rl_bitpos);
3848 end_bit = MAX (ll_bitpos + ll_bitsize, rl_bitpos + rl_bitsize);
3849 lnmode = get_best_mode (end_bit - first_bit, first_bit,
3850 TYPE_ALIGN (TREE_TYPE (ll_inner)), word_mode,
3852 if (lnmode == VOIDmode)
3855 lnbitsize = GET_MODE_BITSIZE (lnmode);
3856 lnbitpos = first_bit & ~ (lnbitsize - 1);
3857 lntype = type_for_size (lnbitsize, 1);
3858 xll_bitpos = ll_bitpos - lnbitpos, xrl_bitpos = rl_bitpos - lnbitpos;
3860 if (BYTES_BIG_ENDIAN)
3862 xll_bitpos = lnbitsize - xll_bitpos - ll_bitsize;
3863 xrl_bitpos = lnbitsize - xrl_bitpos - rl_bitsize;
3866 ll_mask = const_binop (LSHIFT_EXPR, convert (lntype, ll_mask),
3867 size_int (xll_bitpos), 0);
3868 rl_mask = const_binop (LSHIFT_EXPR, convert (lntype, rl_mask),
3869 size_int (xrl_bitpos), 0);
3873 l_const = convert (lntype, l_const);
3874 l_const = unextend (l_const, ll_bitsize, ll_unsignedp, ll_and_mask);
3875 l_const = const_binop (LSHIFT_EXPR, l_const, size_int (xll_bitpos), 0);
3876 if (! integer_zerop (const_binop (BIT_AND_EXPR, l_const,
3877 fold (build1 (BIT_NOT_EXPR,
3881 warning ("comparison is always %d", wanted_code == NE_EXPR);
3883 return convert (truth_type,
3884 wanted_code == NE_EXPR
3885 ? integer_one_node : integer_zero_node);
3890 r_const = convert (lntype, r_const);
3891 r_const = unextend (r_const, rl_bitsize, rl_unsignedp, rl_and_mask);
3892 r_const = const_binop (LSHIFT_EXPR, r_const, size_int (xrl_bitpos), 0);
3893 if (! integer_zerop (const_binop (BIT_AND_EXPR, r_const,
3894 fold (build1 (BIT_NOT_EXPR,
3898 warning ("comparison is always %d", wanted_code == NE_EXPR);
3900 return convert (truth_type,
3901 wanted_code == NE_EXPR
3902 ? integer_one_node : integer_zero_node);
3906 /* If the right sides are not constant, do the same for it. Also,
3907 disallow this optimization if a size or signedness mismatch occurs
3908 between the left and right sides. */
3911 if (ll_bitsize != lr_bitsize || rl_bitsize != rr_bitsize
3912 || ll_unsignedp != lr_unsignedp || rl_unsignedp != rr_unsignedp
3913 /* Make sure the two fields on the right
3914 correspond to the left without being swapped. */
3915 || ll_bitpos - rl_bitpos != lr_bitpos - rr_bitpos)
3918 first_bit = MIN (lr_bitpos, rr_bitpos);
3919 end_bit = MAX (lr_bitpos + lr_bitsize, rr_bitpos + rr_bitsize);
3920 rnmode = get_best_mode (end_bit - first_bit, first_bit,
3921 TYPE_ALIGN (TREE_TYPE (lr_inner)), word_mode,
3923 if (rnmode == VOIDmode)
3926 rnbitsize = GET_MODE_BITSIZE (rnmode);
3927 rnbitpos = first_bit & ~ (rnbitsize - 1);
3928 rntype = type_for_size (rnbitsize, 1);
3929 xlr_bitpos = lr_bitpos - rnbitpos, xrr_bitpos = rr_bitpos - rnbitpos;
3931 if (BYTES_BIG_ENDIAN)
3933 xlr_bitpos = rnbitsize - xlr_bitpos - lr_bitsize;
3934 xrr_bitpos = rnbitsize - xrr_bitpos - rr_bitsize;
3937 lr_mask = const_binop (LSHIFT_EXPR, convert (rntype, lr_mask),
3938 size_int (xlr_bitpos), 0);
3939 rr_mask = const_binop (LSHIFT_EXPR, convert (rntype, rr_mask),
3940 size_int (xrr_bitpos), 0);
3942 /* Make a mask that corresponds to both fields being compared.
3943 Do this for both items being compared. If the operands are the
3944 same size and the bits being compared are in the same position
3945 then we can do this by masking both and comparing the masked
3947 ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask, 0);
3948 lr_mask = const_binop (BIT_IOR_EXPR, lr_mask, rr_mask, 0);
3949 if (lnbitsize == rnbitsize && xll_bitpos == xlr_bitpos)
3951 lhs = make_bit_field_ref (ll_inner, lntype, lnbitsize, lnbitpos,
3952 ll_unsignedp || rl_unsignedp);
3953 if (! all_ones_mask_p (ll_mask, lnbitsize))
3954 lhs = build (BIT_AND_EXPR, lntype, lhs, ll_mask);
3956 rhs = make_bit_field_ref (lr_inner, rntype, rnbitsize, rnbitpos,
3957 lr_unsignedp || rr_unsignedp);
3958 if (! all_ones_mask_p (lr_mask, rnbitsize))
3959 rhs = build (BIT_AND_EXPR, rntype, rhs, lr_mask);
3961 return build (wanted_code, truth_type, lhs, rhs);
3964 /* There is still another way we can do something: If both pairs of
3965 fields being compared are adjacent, we may be able to make a wider
3966 field containing them both.
3968 Note that we still must mask the lhs/rhs expressions. Furthermore,
3969 the mask must be shifted to account for the shift done by
3970 make_bit_field_ref. */
3971 if ((ll_bitsize + ll_bitpos == rl_bitpos
3972 && lr_bitsize + lr_bitpos == rr_bitpos)
3973 || (ll_bitpos == rl_bitpos + rl_bitsize
3974 && lr_bitpos == rr_bitpos + rr_bitsize))
3978 lhs = make_bit_field_ref (ll_inner, lntype, ll_bitsize + rl_bitsize,
3979 MIN (ll_bitpos, rl_bitpos), ll_unsignedp);
3980 rhs = make_bit_field_ref (lr_inner, rntype, lr_bitsize + rr_bitsize,
3981 MIN (lr_bitpos, rr_bitpos), lr_unsignedp);
3983 ll_mask = const_binop (RSHIFT_EXPR, ll_mask,
3984 size_int (MIN (xll_bitpos, xrl_bitpos)), 0);
3985 lr_mask = const_binop (RSHIFT_EXPR, lr_mask,
3986 size_int (MIN (xlr_bitpos, xrr_bitpos)), 0);
3988 /* Convert to the smaller type before masking out unwanted bits. */
3990 if (lntype != rntype)
3992 if (lnbitsize > rnbitsize)
3994 lhs = convert (rntype, lhs);
3995 ll_mask = convert (rntype, ll_mask);
3998 else if (lnbitsize < rnbitsize)
4000 rhs = convert (lntype, rhs);
4001 lr_mask = convert (lntype, lr_mask);
4006 if (! all_ones_mask_p (ll_mask, ll_bitsize + rl_bitsize))
4007 lhs = build (BIT_AND_EXPR, type, lhs, ll_mask);
4009 if (! all_ones_mask_p (lr_mask, lr_bitsize + rr_bitsize))
4010 rhs = build (BIT_AND_EXPR, type, rhs, lr_mask);
4012 return build (wanted_code, truth_type, lhs, rhs);
4018 /* Handle the case of comparisons with constants. If there is something in
4019 common between the masks, those bits of the constants must be the same.
4020 If not, the condition is always false. Test for this to avoid generating
4021 incorrect code below. */
4022 result = const_binop (BIT_AND_EXPR, ll_mask, rl_mask, 0);
4023 if (! integer_zerop (result)
4024 && simple_cst_equal (const_binop (BIT_AND_EXPR, result, l_const, 0),
4025 const_binop (BIT_AND_EXPR, result, r_const, 0)) != 1)
4027 if (wanted_code == NE_EXPR)
4029 warning ("`or' of unmatched not-equal tests is always 1");
4030 return convert (truth_type, integer_one_node);
4034 warning ("`and' of mutually exclusive equal-tests is always 0");
4035 return convert (truth_type, integer_zero_node);
4039 /* Construct the expression we will return. First get the component
4040 reference we will make. Unless the mask is all ones the width of
4041 that field, perform the mask operation. Then compare with the
4043 result = make_bit_field_ref (ll_inner, lntype, lnbitsize, lnbitpos,
4044 ll_unsignedp || rl_unsignedp);
4046 ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask, 0);
4047 if (! all_ones_mask_p (ll_mask, lnbitsize))
4048 result = build (BIT_AND_EXPR, lntype, result, ll_mask);
4050 return build (wanted_code, truth_type, result,
4051 const_binop (BIT_IOR_EXPR, l_const, r_const, 0));
4054 /* If T contains a COMPOUND_EXPR which was inserted merely to evaluate
4055 S, a SAVE_EXPR, return the expression actually being evaluated. Note
4056 that we may sometimes modify the tree. */
4059 strip_compound_expr (t, s)
4063 enum tree_code code = TREE_CODE (t);
4065 /* See if this is the COMPOUND_EXPR we want to eliminate. */
4066 if (code == COMPOUND_EXPR && TREE_CODE (TREE_OPERAND (t, 0)) == CONVERT_EXPR
4067 && TREE_OPERAND (TREE_OPERAND (t, 0), 0) == s)
4068 return TREE_OPERAND (t, 1);
4070 /* See if this is a COND_EXPR or a simple arithmetic operator. We
4071 don't bother handling any other types. */
4072 else if (code == COND_EXPR)
4074 TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
4075 TREE_OPERAND (t, 1) = strip_compound_expr (TREE_OPERAND (t, 1), s);
4076 TREE_OPERAND (t, 2) = strip_compound_expr (TREE_OPERAND (t, 2), s);
4078 else if (TREE_CODE_CLASS (code) == '1')
4079 TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
4080 else if (TREE_CODE_CLASS (code) == '<'
4081 || TREE_CODE_CLASS (code) == '2')
4083 TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
4084 TREE_OPERAND (t, 1) = strip_compound_expr (TREE_OPERAND (t, 1), s);
4090 /* Return a node which has the indicated constant VALUE (either 0 or
4091 1), and is of the indicated TYPE. */
4094 constant_boolean_node (value, type)
4098 if (type == integer_type_node)
4099 return value ? integer_one_node : integer_zero_node;
4100 else if (TREE_CODE (type) == BOOLEAN_TYPE)
4101 return truthvalue_conversion (value ? integer_one_node :
4105 tree t = build_int_2 (value, 0);
4106 TREE_TYPE (t) = type;
4111 /* Utility function for the following routine, to see how complex a nesting of
4112 COND_EXPRs can be. EXPR is the expression and LIMIT is a count beyond which
4113 we don't care (to avoid spending too much time on complex expressions.). */
4116 count_cond (expr, lim)
4122 if (TREE_CODE (expr) != COND_EXPR)
4127 true = count_cond (TREE_OPERAND (expr, 1), lim - 1);
4128 false = count_cond (TREE_OPERAND (expr, 2), lim - 1 - true);
4129 return MIN (lim, 1 + true + false);
4132 /* Perform constant folding and related simplification of EXPR.
4133 The related simplifications include x*1 => x, x*0 => 0, etc.,
4134 and application of the associative law.
4135 NOP_EXPR conversions may be removed freely (as long as we
4136 are careful not to change the C type of the overall expression)
4137 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
4138 but we can constant-fold them if they have constant operands. */
4144 register tree t = expr;
4145 tree t1 = NULL_TREE;
4147 tree type = TREE_TYPE (expr);
4148 register tree arg0 = NULL_TREE, arg1 = NULL_TREE;
4149 register enum tree_code code = TREE_CODE (t);
4153 /* WINS will be nonzero when the switch is done
4154 if all operands are constant. */
4158 /* Don't try to process an RTL_EXPR since its operands aren't trees.
4159 Likewise for a SAVE_EXPR that's already been evaluated. */
4160 if (code == RTL_EXPR || (code == SAVE_EXPR && SAVE_EXPR_RTL (t)) != 0)
4163 /* Return right away if already constant. */
4164 if (TREE_CONSTANT (t))
4166 if (code == CONST_DECL)
4167 return DECL_INITIAL (t);
4171 #ifdef MAX_INTEGER_COMPUTATION_MODE
4172 check_max_integer_computation_mode (expr);
4175 kind = TREE_CODE_CLASS (code);
4176 if (code == NOP_EXPR || code == FLOAT_EXPR || code == CONVERT_EXPR)
4180 /* Special case for conversion ops that can have fixed point args. */
4181 arg0 = TREE_OPERAND (t, 0);
4183 /* Don't use STRIP_NOPS, because signedness of argument type matters. */
4185 STRIP_TYPE_NOPS (arg0);
4187 if (arg0 != 0 && TREE_CODE (arg0) == COMPLEX_CST)
4188 subop = TREE_REALPART (arg0);
4192 if (subop != 0 && TREE_CODE (subop) != INTEGER_CST
4193 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
4194 && TREE_CODE (subop) != REAL_CST
4195 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
4197 /* Note that TREE_CONSTANT isn't enough:
4198 static var addresses are constant but we can't
4199 do arithmetic on them. */
4202 else if (kind == 'e' || kind == '<'
4203 || kind == '1' || kind == '2' || kind == 'r')
4205 register int len = tree_code_length[(int) code];
4207 for (i = 0; i < len; i++)
4209 tree op = TREE_OPERAND (t, i);
4213 continue; /* Valid for CALL_EXPR, at least. */
4215 if (kind == '<' || code == RSHIFT_EXPR)
4217 /* Signedness matters here. Perhaps we can refine this
4219 STRIP_TYPE_NOPS (op);
4223 /* Strip any conversions that don't change the mode. */
4227 if (TREE_CODE (op) == COMPLEX_CST)
4228 subop = TREE_REALPART (op);
4232 if (TREE_CODE (subop) != INTEGER_CST
4233 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
4234 && TREE_CODE (subop) != REAL_CST
4235 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
4237 /* Note that TREE_CONSTANT isn't enough:
4238 static var addresses are constant but we can't
4239 do arithmetic on them. */
4249 /* If this is a commutative operation, and ARG0 is a constant, move it
4250 to ARG1 to reduce the number of tests below. */
4251 if ((code == PLUS_EXPR || code == MULT_EXPR || code == MIN_EXPR
4252 || code == MAX_EXPR || code == BIT_IOR_EXPR || code == BIT_XOR_EXPR
4253 || code == BIT_AND_EXPR)
4254 && (TREE_CODE (arg0) == INTEGER_CST || TREE_CODE (arg0) == REAL_CST))
4256 tem = arg0; arg0 = arg1; arg1 = tem;
4258 tem = TREE_OPERAND (t, 0); TREE_OPERAND (t, 0) = TREE_OPERAND (t, 1);
4259 TREE_OPERAND (t, 1) = tem;
4262 /* Now WINS is set as described above,
4263 ARG0 is the first operand of EXPR,
4264 and ARG1 is the second operand (if it has more than one operand).
4266 First check for cases where an arithmetic operation is applied to a
4267 compound, conditional, or comparison operation. Push the arithmetic
4268 operation inside the compound or conditional to see if any folding
4269 can then be done. Convert comparison to conditional for this purpose.
4270 The also optimizes non-constant cases that used to be done in
4273 Before we do that, see if this is a BIT_AND_EXPR or a BIT_OR_EXPR,
4274 one of the operands is a comparison and the other is a comparison, a
4275 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
4276 code below would make the expression more complex. Change it to a
4277 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
4278 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
4280 if ((code == BIT_AND_EXPR || code == BIT_IOR_EXPR
4281 || code == EQ_EXPR || code == NE_EXPR)
4282 && ((truth_value_p (TREE_CODE (arg0))
4283 && (truth_value_p (TREE_CODE (arg1))
4284 || (TREE_CODE (arg1) == BIT_AND_EXPR
4285 && integer_onep (TREE_OPERAND (arg1, 1)))))
4286 || (truth_value_p (TREE_CODE (arg1))
4287 && (truth_value_p (TREE_CODE (arg0))
4288 || (TREE_CODE (arg0) == BIT_AND_EXPR
4289 && integer_onep (TREE_OPERAND (arg0, 1)))))))
4291 t = fold (build (code == BIT_AND_EXPR ? TRUTH_AND_EXPR
4292 : code == BIT_IOR_EXPR ? TRUTH_OR_EXPR
4296 if (code == EQ_EXPR)
4297 t = invert_truthvalue (t);
4302 if (TREE_CODE_CLASS (code) == '1')
4304 if (TREE_CODE (arg0) == COMPOUND_EXPR)
4305 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
4306 fold (build1 (code, type, TREE_OPERAND (arg0, 1))));
4307 else if (TREE_CODE (arg0) == COND_EXPR)
4309 t = fold (build (COND_EXPR, type, TREE_OPERAND (arg0, 0),
4310 fold (build1 (code, type, TREE_OPERAND (arg0, 1))),
4311 fold (build1 (code, type, TREE_OPERAND (arg0, 2)))));
4313 /* If this was a conversion, and all we did was to move into
4314 inside the COND_EXPR, bring it back out. But leave it if
4315 it is a conversion from integer to integer and the
4316 result precision is no wider than a word since such a
4317 conversion is cheap and may be optimized away by combine,
4318 while it couldn't if it were outside the COND_EXPR. Then return
4319 so we don't get into an infinite recursion loop taking the
4320 conversion out and then back in. */
4322 if ((code == NOP_EXPR || code == CONVERT_EXPR
4323 || code == NON_LVALUE_EXPR)
4324 && TREE_CODE (t) == COND_EXPR
4325 && TREE_CODE (TREE_OPERAND (t, 1)) == code
4326 && TREE_CODE (TREE_OPERAND (t, 2)) == code
4327 && (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0))
4328 == TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 2), 0)))
4329 && ! (INTEGRAL_TYPE_P (TREE_TYPE (t))
4330 && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0)))
4331 && TYPE_PRECISION (TREE_TYPE (t)) <= BITS_PER_WORD))
4332 t = build1 (code, type,
4334 TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0)),
4335 TREE_OPERAND (t, 0),
4336 TREE_OPERAND (TREE_OPERAND (t, 1), 0),
4337 TREE_OPERAND (TREE_OPERAND (t, 2), 0)));
4340 else if (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<')
4341 return fold (build (COND_EXPR, type, arg0,
4342 fold (build1 (code, type, integer_one_node)),
4343 fold (build1 (code, type, integer_zero_node))));
4345 else if (TREE_CODE_CLASS (code) == '2'
4346 || TREE_CODE_CLASS (code) == '<')
4348 if (TREE_CODE (arg1) == COMPOUND_EXPR)
4349 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0),
4350 fold (build (code, type,
4351 arg0, TREE_OPERAND (arg1, 1))));
4352 else if ((TREE_CODE (arg1) == COND_EXPR
4353 || (TREE_CODE_CLASS (TREE_CODE (arg1)) == '<'
4354 && TREE_CODE_CLASS (code) != '<'))
4355 && (TREE_CODE (arg0) != COND_EXPR
4356 || count_cond (arg0, 25) + count_cond (arg1, 25) <= 25)
4357 && (! TREE_SIDE_EFFECTS (arg0)
4358 || (global_bindings_p () == 0
4359 && ! contains_placeholder_p (arg0))))
4361 tree test, true_value, false_value;
4362 tree lhs = 0, rhs = 0;
4364 if (TREE_CODE (arg1) == COND_EXPR)
4366 test = TREE_OPERAND (arg1, 0);
4367 true_value = TREE_OPERAND (arg1, 1);
4368 false_value = TREE_OPERAND (arg1, 2);
4372 tree testtype = TREE_TYPE (arg1);
4374 true_value = convert (testtype, integer_one_node);
4375 false_value = convert (testtype, integer_zero_node);
4378 /* If ARG0 is complex we want to make sure we only evaluate
4379 it once. Though this is only required if it is volatile, it
4380 might be more efficient even if it is not. However, if we
4381 succeed in folding one part to a constant, we do not need
4382 to make this SAVE_EXPR. Since we do this optimization
4383 primarily to see if we do end up with constant and this
4384 SAVE_EXPR interferes with later optimizations, suppressing
4385 it when we can is important.
4387 If we are not in a function, we can't make a SAVE_EXPR, so don't
4388 try to do so. Don't try to see if the result is a constant
4389 if an arm is a COND_EXPR since we get exponential behavior
4392 if (TREE_CODE (arg0) != SAVE_EXPR && ! TREE_CONSTANT (arg0)
4393 && global_bindings_p () == 0
4394 && ((TREE_CODE (arg0) != VAR_DECL
4395 && TREE_CODE (arg0) != PARM_DECL)
4396 || TREE_SIDE_EFFECTS (arg0)))
4398 if (TREE_CODE (true_value) != COND_EXPR)
4399 lhs = fold (build (code, type, arg0, true_value));
4401 if (TREE_CODE (false_value) != COND_EXPR)
4402 rhs = fold (build (code, type, arg0, false_value));
4404 if ((lhs == 0 || ! TREE_CONSTANT (lhs))
4405 && (rhs == 0 || !TREE_CONSTANT (rhs)))
4406 arg0 = save_expr (arg0), lhs = rhs = 0;
4410 lhs = fold (build (code, type, arg0, true_value));
4412 rhs = fold (build (code, type, arg0, false_value));
4414 test = fold (build (COND_EXPR, type, test, lhs, rhs));
4416 if (TREE_CODE (arg0) == SAVE_EXPR)
4417 return build (COMPOUND_EXPR, type,
4418 convert (void_type_node, arg0),
4419 strip_compound_expr (test, arg0));
4421 return convert (type, test);
4424 else if (TREE_CODE (arg0) == COMPOUND_EXPR)
4425 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
4426 fold (build (code, type, TREE_OPERAND (arg0, 1), arg1)));
4427 else if ((TREE_CODE (arg0) == COND_EXPR
4428 || (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
4429 && TREE_CODE_CLASS (code) != '<'))
4430 && (TREE_CODE (arg1) != COND_EXPR
4431 || count_cond (arg0, 25) + count_cond (arg1, 25) <= 25)
4432 && (! TREE_SIDE_EFFECTS (arg1)
4433 || (global_bindings_p () == 0
4434 && ! contains_placeholder_p (arg1))))
4436 tree test, true_value, false_value;
4437 tree lhs = 0, rhs = 0;
4439 if (TREE_CODE (arg0) == COND_EXPR)
4441 test = TREE_OPERAND (arg0, 0);
4442 true_value = TREE_OPERAND (arg0, 1);
4443 false_value = TREE_OPERAND (arg0, 2);
4447 tree testtype = TREE_TYPE (arg0);
4449 true_value = convert (testtype, integer_one_node);
4450 false_value = convert (testtype, integer_zero_node);
4453 if (TREE_CODE (arg1) != SAVE_EXPR && ! TREE_CONSTANT (arg0)
4454 && global_bindings_p () == 0
4455 && ((TREE_CODE (arg1) != VAR_DECL
4456 && TREE_CODE (arg1) != PARM_DECL)
4457 || TREE_SIDE_EFFECTS (arg1)))
4459 if (TREE_CODE (true_value) != COND_EXPR)
4460 lhs = fold (build (code, type, true_value, arg1));
4462 if (TREE_CODE (false_value) != COND_EXPR)
4463 rhs = fold (build (code, type, false_value, arg1));
4465 if ((lhs == 0 || ! TREE_CONSTANT (lhs))
4466 && (rhs == 0 || !TREE_CONSTANT (rhs)))
4467 arg1 = save_expr (arg1), lhs = rhs = 0;
4471 lhs = fold (build (code, type, true_value, arg1));
4474 rhs = fold (build (code, type, false_value, arg1));
4476 test = fold (build (COND_EXPR, type, test, lhs, rhs));
4477 if (TREE_CODE (arg1) == SAVE_EXPR)
4478 return build (COMPOUND_EXPR, type,
4479 convert (void_type_node, arg1),
4480 strip_compound_expr (test, arg1));
4482 return convert (type, test);
4485 else if (TREE_CODE_CLASS (code) == '<'
4486 && TREE_CODE (arg0) == COMPOUND_EXPR)
4487 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
4488 fold (build (code, type, TREE_OPERAND (arg0, 1), arg1)));
4489 else if (TREE_CODE_CLASS (code) == '<'
4490 && TREE_CODE (arg1) == COMPOUND_EXPR)
4491 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0),
4492 fold (build (code, type, arg0, TREE_OPERAND (arg1, 1))));
4504 return fold (DECL_INITIAL (t));
4509 case FIX_TRUNC_EXPR:
4510 /* Other kinds of FIX are not handled properly by fold_convert. */
4512 if (TREE_TYPE (TREE_OPERAND (t, 0)) == TREE_TYPE (t))
4513 return TREE_OPERAND (t, 0);
4515 /* Handle cases of two conversions in a row. */
4516 if (TREE_CODE (TREE_OPERAND (t, 0)) == NOP_EXPR
4517 || TREE_CODE (TREE_OPERAND (t, 0)) == CONVERT_EXPR)
4519 tree inside_type = TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0));
4520 tree inter_type = TREE_TYPE (TREE_OPERAND (t, 0));
4521 tree final_type = TREE_TYPE (t);
4522 int inside_int = INTEGRAL_TYPE_P (inside_type);
4523 int inside_ptr = POINTER_TYPE_P (inside_type);
4524 int inside_float = FLOAT_TYPE_P (inside_type);
4525 int inside_prec = TYPE_PRECISION (inside_type);
4526 int inside_unsignedp = TREE_UNSIGNED (inside_type);
4527 int inter_int = INTEGRAL_TYPE_P (inter_type);
4528 int inter_ptr = POINTER_TYPE_P (inter_type);
4529 int inter_float = FLOAT_TYPE_P (inter_type);
4530 int inter_prec = TYPE_PRECISION (inter_type);
4531 int inter_unsignedp = TREE_UNSIGNED (inter_type);
4532 int final_int = INTEGRAL_TYPE_P (final_type);
4533 int final_ptr = POINTER_TYPE_P (final_type);
4534 int final_float = FLOAT_TYPE_P (final_type);
4535 int final_prec = TYPE_PRECISION (final_type);
4536 int final_unsignedp = TREE_UNSIGNED (final_type);
4538 /* In addition to the cases of two conversions in a row
4539 handled below, if we are converting something to its own
4540 type via an object of identical or wider precision, neither
4541 conversion is needed. */
4542 if (inside_type == final_type
4543 && ((inter_int && final_int) || (inter_float && final_float))
4544 && inter_prec >= final_prec)
4545 return TREE_OPERAND (TREE_OPERAND (t, 0), 0);
4547 /* Likewise, if the intermediate and final types are either both
4548 float or both integer, we don't need the middle conversion if
4549 it is wider than the final type and doesn't change the signedness
4550 (for integers). Avoid this if the final type is a pointer
4551 since then we sometimes need the inner conversion. Likewise if
4552 the outer has a precision not equal to the size of its mode. */
4553 if ((((inter_int || inter_ptr) && (inside_int || inside_ptr))
4554 || (inter_float && inside_float))
4555 && inter_prec >= inside_prec
4556 && (inter_float || inter_unsignedp == inside_unsignedp)
4557 && ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (final_type))
4558 && TYPE_MODE (final_type) == TYPE_MODE (inter_type))
4560 return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
4562 /* If we have a sign-extension of a zero-extended value, we can
4563 replace that by a single zero-extension. */
4564 if (inside_int && inter_int && final_int
4565 && inside_prec < inter_prec && inter_prec < final_prec
4566 && inside_unsignedp && !inter_unsignedp)
4567 return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
4569 /* Two conversions in a row are not needed unless:
4570 - some conversion is floating-point (overstrict for now), or
4571 - the intermediate type is narrower than both initial and
4573 - the intermediate type and innermost type differ in signedness,
4574 and the outermost type is wider than the intermediate, or
4575 - the initial type is a pointer type and the precisions of the
4576 intermediate and final types differ, or
4577 - the final type is a pointer type and the precisions of the
4578 initial and intermediate types differ. */
4579 if (! inside_float && ! inter_float && ! final_float
4580 && (inter_prec > inside_prec || inter_prec > final_prec)
4581 && ! (inside_int && inter_int
4582 && inter_unsignedp != inside_unsignedp
4583 && inter_prec < final_prec)
4584 && ((inter_unsignedp && inter_prec > inside_prec)
4585 == (final_unsignedp && final_prec > inter_prec))
4586 && ! (inside_ptr && inter_prec != final_prec)
4587 && ! (final_ptr && inside_prec != inter_prec)
4588 && ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (final_type))
4589 && TYPE_MODE (final_type) == TYPE_MODE (inter_type))
4591 return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
4594 if (TREE_CODE (TREE_OPERAND (t, 0)) == MODIFY_EXPR
4595 && TREE_CONSTANT (TREE_OPERAND (TREE_OPERAND (t, 0), 1))
4596 /* Detect assigning a bitfield. */
4597 && !(TREE_CODE (TREE_OPERAND (TREE_OPERAND (t, 0), 0)) == COMPONENT_REF
4598 && DECL_BIT_FIELD (TREE_OPERAND (TREE_OPERAND (TREE_OPERAND (t, 0), 0), 1))))
4600 /* Don't leave an assignment inside a conversion
4601 unless assigning a bitfield. */
4602 tree prev = TREE_OPERAND (t, 0);
4603 TREE_OPERAND (t, 0) = TREE_OPERAND (prev, 1);
4604 /* First do the assignment, then return converted constant. */
4605 t = build (COMPOUND_EXPR, TREE_TYPE (t), prev, fold (t));
4611 TREE_CONSTANT (t) = TREE_CONSTANT (arg0);
4614 return fold_convert (t, arg0);
4616 #if 0 /* This loses on &"foo"[0]. */
4621 /* Fold an expression like: "foo"[2] */
4622 if (TREE_CODE (arg0) == STRING_CST
4623 && TREE_CODE (arg1) == INTEGER_CST
4624 && !TREE_INT_CST_HIGH (arg1)
4625 && (i = TREE_INT_CST_LOW (arg1)) < TREE_STRING_LENGTH (arg0))
4627 t = build_int_2 (TREE_STRING_POINTER (arg0)[i], 0);
4628 TREE_TYPE (t) = TREE_TYPE (TREE_TYPE (arg0));
4629 force_fit_type (t, 0);
4636 if (TREE_CODE (arg0) == CONSTRUCTOR)
4638 tree m = purpose_member (arg1, CONSTRUCTOR_ELTS (arg0));
4645 TREE_CONSTANT (t) = wins;
4651 if (TREE_CODE (arg0) == INTEGER_CST)
4653 HOST_WIDE_INT low, high;
4654 int overflow = neg_double (TREE_INT_CST_LOW (arg0),
4655 TREE_INT_CST_HIGH (arg0),
4657 t = build_int_2 (low, high);
4658 TREE_TYPE (t) = type;
4660 = (TREE_OVERFLOW (arg0)
4661 | force_fit_type (t, overflow && !TREE_UNSIGNED (type)));
4662 TREE_CONSTANT_OVERFLOW (t)
4663 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg0);
4665 else if (TREE_CODE (arg0) == REAL_CST)
4666 t = build_real (type, REAL_VALUE_NEGATE (TREE_REAL_CST (arg0)));
4668 else if (TREE_CODE (arg0) == NEGATE_EXPR)
4669 return TREE_OPERAND (arg0, 0);
4671 /* Convert - (a - b) to (b - a) for non-floating-point. */
4672 else if (TREE_CODE (arg0) == MINUS_EXPR && ! FLOAT_TYPE_P (type))
4673 return build (MINUS_EXPR, type, TREE_OPERAND (arg0, 1),
4674 TREE_OPERAND (arg0, 0));
4681 if (TREE_CODE (arg0) == INTEGER_CST)
4683 if (! TREE_UNSIGNED (type)
4684 && TREE_INT_CST_HIGH (arg0) < 0)
4686 HOST_WIDE_INT low, high;
4687 int overflow = neg_double (TREE_INT_CST_LOW (arg0),
4688 TREE_INT_CST_HIGH (arg0),
4690 t = build_int_2 (low, high);
4691 TREE_TYPE (t) = type;
4693 = (TREE_OVERFLOW (arg0)
4694 | force_fit_type (t, overflow));
4695 TREE_CONSTANT_OVERFLOW (t)
4696 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg0);
4699 else if (TREE_CODE (arg0) == REAL_CST)
4701 if (REAL_VALUE_NEGATIVE (TREE_REAL_CST (arg0)))
4702 t = build_real (type,
4703 REAL_VALUE_NEGATE (TREE_REAL_CST (arg0)));
4706 else if (TREE_CODE (arg0) == ABS_EXPR || TREE_CODE (arg0) == NEGATE_EXPR)
4707 return build1 (ABS_EXPR, type, TREE_OPERAND (arg0, 0));
4711 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
4713 else if (TREE_CODE (arg0) == COMPLEX_EXPR)
4714 return build (COMPLEX_EXPR, TREE_TYPE (arg0),
4715 TREE_OPERAND (arg0, 0),
4716 fold (build1 (NEGATE_EXPR,
4717 TREE_TYPE (TREE_TYPE (arg0)),
4718 TREE_OPERAND (arg0, 1))));
4719 else if (TREE_CODE (arg0) == COMPLEX_CST)
4720 return build_complex (type, TREE_OPERAND (arg0, 0),
4721 fold (build1 (NEGATE_EXPR,
4722 TREE_TYPE (TREE_TYPE (arg0)),
4723 TREE_OPERAND (arg0, 1))));
4724 else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
4725 return fold (build (TREE_CODE (arg0), type,
4726 fold (build1 (CONJ_EXPR, type,
4727 TREE_OPERAND (arg0, 0))),
4728 fold (build1 (CONJ_EXPR,
4729 type, TREE_OPERAND (arg0, 1)))));
4730 else if (TREE_CODE (arg0) == CONJ_EXPR)
4731 return TREE_OPERAND (arg0, 0);
4737 t = build_int_2 (~ TREE_INT_CST_LOW (arg0),
4738 ~ TREE_INT_CST_HIGH (arg0));
4739 TREE_TYPE (t) = type;
4740 force_fit_type (t, 0);
4741 TREE_OVERFLOW (t) = TREE_OVERFLOW (arg0);
4742 TREE_CONSTANT_OVERFLOW (t) = TREE_CONSTANT_OVERFLOW (arg0);
4744 else if (TREE_CODE (arg0) == BIT_NOT_EXPR)
4745 return TREE_OPERAND (arg0, 0);
4749 /* A + (-B) -> A - B */
4750 if (TREE_CODE (arg1) == NEGATE_EXPR)
4751 return fold (build (MINUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0)));
4752 else if (! FLOAT_TYPE_P (type))
4754 if (integer_zerop (arg1))
4755 return non_lvalue (convert (type, arg0));
4757 /* If we are adding two BIT_AND_EXPR's, both of which are and'ing
4758 with a constant, and the two constants have no bits in common,
4759 we should treat this as a BIT_IOR_EXPR since this may produce more
4761 if (TREE_CODE (arg0) == BIT_AND_EXPR
4762 && TREE_CODE (arg1) == BIT_AND_EXPR
4763 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
4764 && TREE_CODE (TREE_OPERAND (arg1, 1)) == INTEGER_CST
4765 && integer_zerop (const_binop (BIT_AND_EXPR,
4766 TREE_OPERAND (arg0, 1),
4767 TREE_OPERAND (arg1, 1), 0)))
4769 code = BIT_IOR_EXPR;
4773 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
4774 (plus (plus (mult) (mult)) (foo)) so that we can
4775 take advantage of the factoring cases below. */
4776 if ((TREE_CODE (arg0) == PLUS_EXPR
4777 && TREE_CODE (arg1) == MULT_EXPR)
4778 || (TREE_CODE (arg1) == PLUS_EXPR
4779 && TREE_CODE (arg0) == MULT_EXPR))
4781 tree parg0, parg1, parg, marg;
4783 if (TREE_CODE (arg0) == PLUS_EXPR)
4784 parg = arg0, marg = arg1;
4786 parg = arg1, marg = arg0;
4787 parg0 = TREE_OPERAND (parg, 0);
4788 parg1 = TREE_OPERAND (parg, 1);
4792 if (TREE_CODE (parg0) == MULT_EXPR
4793 && TREE_CODE (parg1) != MULT_EXPR)
4794 return fold (build (PLUS_EXPR, type,
4795 fold (build (PLUS_EXPR, type, parg0, marg)),
4797 if (TREE_CODE (parg0) != MULT_EXPR
4798 && TREE_CODE (parg1) == MULT_EXPR)
4799 return fold (build (PLUS_EXPR, type,
4800 fold (build (PLUS_EXPR, type, parg1, marg)),
4804 if (TREE_CODE (arg0) == MULT_EXPR && TREE_CODE (arg1) == MULT_EXPR)
4806 tree arg00, arg01, arg10, arg11;
4807 tree alt0 = NULL_TREE, alt1 = NULL_TREE, same;
4809 /* (A * C) + (B * C) -> (A+B) * C.
4810 We are most concerned about the case where C is a constant,
4811 but other combinations show up during loop reduction. Since
4812 it is not difficult, try all four possibilities. */
4814 arg00 = TREE_OPERAND (arg0, 0);
4815 arg01 = TREE_OPERAND (arg0, 1);
4816 arg10 = TREE_OPERAND (arg1, 0);
4817 arg11 = TREE_OPERAND (arg1, 1);
4820 if (operand_equal_p (arg01, arg11, 0))
4821 same = arg01, alt0 = arg00, alt1 = arg10;
4822 else if (operand_equal_p (arg00, arg10, 0))
4823 same = arg00, alt0 = arg01, alt1 = arg11;
4824 else if (operand_equal_p (arg00, arg11, 0))
4825 same = arg00, alt0 = arg01, alt1 = arg10;
4826 else if (operand_equal_p (arg01, arg10, 0))
4827 same = arg01, alt0 = arg00, alt1 = arg11;
4829 /* No identical multiplicands; see if we can find a common
4830 power-of-two factor in non-power-of-two multiplies. This
4831 can help in multi-dimensional array access. */
4832 else if (TREE_CODE (arg01) == INTEGER_CST
4833 && TREE_CODE (arg11) == INTEGER_CST
4834 && TREE_INT_CST_HIGH (arg01) == 0
4835 && TREE_INT_CST_HIGH (arg11) == 0)
4837 HOST_WIDE_INT int01, int11, tmp;
4838 int01 = TREE_INT_CST_LOW (arg01);
4839 int11 = TREE_INT_CST_LOW (arg11);
4841 /* Move min of absolute values to int11. */
4842 if ((int01 >= 0 ? int01 : -int01)
4843 < (int11 >= 0 ? int11 : -int11))
4845 tmp = int01, int01 = int11, int11 = tmp;
4846 alt0 = arg00, arg00 = arg10, arg10 = alt0;
4847 alt0 = arg01, arg01 = arg11, arg11 = alt0;
4850 if (exact_log2 (int11) > 0 && int01 % int11 == 0)
4852 alt0 = fold (build (MULT_EXPR, type, arg00,
4853 build_int_2 (int01 / int11, 0)));
4860 return fold (build (MULT_EXPR, type,
4861 fold (build (PLUS_EXPR, type, alt0, alt1)),
4865 /* In IEEE floating point, x+0 may not equal x. */
4866 else if ((TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
4868 && real_zerop (arg1))
4869 return non_lvalue (convert (type, arg0));
4871 /* In most languages, can't associate operations on floats
4872 through parentheses. Rather than remember where the parentheses
4873 were, we don't associate floats at all. It shouldn't matter much.
4874 However, associating multiplications is only very slightly
4875 inaccurate, so do that if -ffast-math is specified. */
4876 if (FLOAT_TYPE_P (type)
4877 && ! (flag_fast_math && code == MULT_EXPR))
4880 /* The varsign == -1 cases happen only for addition and subtraction.
4881 It says that the arg that was split was really CON minus VAR.
4882 The rest of the code applies to all associative operations. */
4888 if (split_tree (arg0, code, &var, &con, &varsign))
4892 /* EXPR is (CON-VAR) +- ARG1. */
4893 /* If it is + and VAR==ARG1, return just CONST. */
4894 if (code == PLUS_EXPR && operand_equal_p (var, arg1, 0))
4895 return convert (TREE_TYPE (t), con);
4897 /* If ARG0 is a constant, don't change things around;
4898 instead keep all the constant computations together. */
4900 if (TREE_CONSTANT (arg0))
4903 /* Otherwise return (CON +- ARG1) - VAR. */
4904 t = build (MINUS_EXPR, type,
4905 fold (build (code, type, con, arg1)), var);
4909 /* EXPR is (VAR+CON) +- ARG1. */
4910 /* If it is - and VAR==ARG1, return just CONST. */
4911 if (code == MINUS_EXPR && operand_equal_p (var, arg1, 0))
4912 return convert (TREE_TYPE (t), con);
4914 /* If ARG0 is a constant, don't change things around;
4915 instead keep all the constant computations together. */
4917 if (TREE_CONSTANT (arg0))
4920 /* Otherwise return VAR +- (ARG1 +- CON). */
4921 tem = fold (build (code, type, arg1, con));
4922 t = build (code, type, var, tem);
4924 if (integer_zerop (tem)
4925 && (code == PLUS_EXPR || code == MINUS_EXPR))
4926 return convert (type, var);
4927 /* If we have x +/- (c - d) [c an explicit integer]
4928 change it to x -/+ (d - c) since if d is relocatable
4929 then the latter can be a single immediate insn
4930 and the former cannot. */
4931 if (TREE_CODE (tem) == MINUS_EXPR
4932 && TREE_CODE (TREE_OPERAND (tem, 0)) == INTEGER_CST)
4934 tree tem1 = TREE_OPERAND (tem, 1);
4935 TREE_OPERAND (tem, 1) = TREE_OPERAND (tem, 0);
4936 TREE_OPERAND (tem, 0) = tem1;
4938 (code == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR));
4944 if (split_tree (arg1, code, &var, &con, &varsign))
4946 if (TREE_CONSTANT (arg1))
4951 (code == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR));
4953 /* EXPR is ARG0 +- (CON +- VAR). */
4954 if (TREE_CODE (t) == MINUS_EXPR
4955 && operand_equal_p (var, arg0, 0))
4957 /* If VAR and ARG0 cancel, return just CON or -CON. */
4958 if (code == PLUS_EXPR)
4959 return convert (TREE_TYPE (t), con);
4960 return fold (build1 (NEGATE_EXPR, TREE_TYPE (t),
4961 convert (TREE_TYPE (t), con)));
4964 t = build (TREE_CODE (t), type,
4965 fold (build (code, TREE_TYPE (t), arg0, con)), var);
4967 if (integer_zerop (TREE_OPERAND (t, 0))
4968 && TREE_CODE (t) == PLUS_EXPR)
4969 return convert (TREE_TYPE (t), var);
4974 #if defined (REAL_IS_NOT_DOUBLE) && ! defined (REAL_ARITHMETIC)
4975 if (TREE_CODE (arg1) == REAL_CST)
4977 #endif /* REAL_IS_NOT_DOUBLE, and no REAL_ARITHMETIC */
4979 t1 = const_binop (code, arg0, arg1, 0);
4980 if (t1 != NULL_TREE)
4982 /* The return value should always have
4983 the same type as the original expression. */
4984 if (TREE_TYPE (t1) != TREE_TYPE (t))
4985 t1 = convert (TREE_TYPE (t), t1);
4992 if (! FLOAT_TYPE_P (type))
4994 if (! wins && integer_zerop (arg0))
4995 return build1 (NEGATE_EXPR, type, arg1);
4996 if (integer_zerop (arg1))
4997 return non_lvalue (convert (type, arg0));
4999 /* (A * C) - (B * C) -> (A-B) * C. Since we are most concerned
5000 about the case where C is a constant, just try one of the
5001 four possibilities. */
5003 if (TREE_CODE (arg0) == MULT_EXPR && TREE_CODE (arg1) == MULT_EXPR
5004 && operand_equal_p (TREE_OPERAND (arg0, 1),
5005 TREE_OPERAND (arg1, 1), 0))
5006 return fold (build (MULT_EXPR, type,
5007 fold (build (MINUS_EXPR, type,
5008 TREE_OPERAND (arg0, 0),
5009 TREE_OPERAND (arg1, 0))),
5010 TREE_OPERAND (arg0, 1)));
5012 /* Convert A - (-B) to A + B. */
5013 else if (TREE_CODE (arg1) == NEGATE_EXPR)
5014 return fold (build (PLUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0)));
5016 else if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
5019 /* Except with IEEE floating point, 0-x equals -x. */
5020 if (! wins && real_zerop (arg0))
5021 return build1 (NEGATE_EXPR, type, arg1);
5022 /* Except with IEEE floating point, x-0 equals x. */
5023 if (real_zerop (arg1))
5024 return non_lvalue (convert (type, arg0));
5027 /* Fold &x - &x. This can happen from &x.foo - &x.
5028 This is unsafe for certain floats even in non-IEEE formats.
5029 In IEEE, it is unsafe because it does wrong for NaNs.
5030 Also note that operand_equal_p is always false if an operand
5033 if ((! FLOAT_TYPE_P (type) || flag_fast_math)
5034 && operand_equal_p (arg0, arg1, 0))
5035 return convert (type, integer_zero_node);
5040 if (! FLOAT_TYPE_P (type))
5042 if (integer_zerop (arg1))
5043 return omit_one_operand (type, arg1, arg0);
5044 if (integer_onep (arg1))
5045 return non_lvalue (convert (type, arg0));
5047 /* ((A / C) * C) is A if the division is an
5048 EXACT_DIV_EXPR. Since C is normally a constant,
5049 just check for one of the four possibilities. */
5051 if (TREE_CODE (arg0) == EXACT_DIV_EXPR
5052 && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0))
5053 return TREE_OPERAND (arg0, 0);
5055 /* (a * (1 << b)) is (a << b) */
5056 if (TREE_CODE (arg1) == LSHIFT_EXPR
5057 && integer_onep (TREE_OPERAND (arg1, 0)))
5058 return fold (build (LSHIFT_EXPR, type, arg0,
5059 TREE_OPERAND (arg1, 1)));
5060 if (TREE_CODE (arg0) == LSHIFT_EXPR
5061 && integer_onep (TREE_OPERAND (arg0, 0)))
5062 return fold (build (LSHIFT_EXPR, type, arg1,
5063 TREE_OPERAND (arg0, 1)));
5067 /* x*0 is 0, except for IEEE floating point. */
5068 if ((TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
5070 && real_zerop (arg1))
5071 return omit_one_operand (type, arg1, arg0);
5072 /* In IEEE floating point, x*1 is not equivalent to x for snans.
5073 However, ANSI says we can drop signals,
5074 so we can do this anyway. */
5075 if (real_onep (arg1))
5076 return non_lvalue (convert (type, arg0));
5078 if (! wins && real_twop (arg1) && global_bindings_p () == 0
5079 && ! contains_placeholder_p (arg0))
5081 tree arg = save_expr (arg0);
5082 return build (PLUS_EXPR, type, arg, arg);
5090 register enum tree_code code0, code1;
5092 if (integer_all_onesp (arg1))
5093 return omit_one_operand (type, arg1, arg0);
5094 if (integer_zerop (arg1))
5095 return non_lvalue (convert (type, arg0));
5096 t1 = distribute_bit_expr (code, type, arg0, arg1);
5097 if (t1 != NULL_TREE)
5101 /* (A << C1) | (A >> C2) if A is unsigned and C1+C2 is the size of A
5102 is a rotate of A by C1 bits. */
5103 /* (A << B) | (A >> (Z - B)) if A is unsigned and Z is the size of A
5104 is a rotate of A by B bits. */
5106 /* Both transformations noted above also apply to when the inner
5107 operation is an XOR. */
5109 code0 = TREE_CODE (arg0);
5110 code1 = TREE_CODE (arg1);
5111 if (((code0 == RSHIFT_EXPR && code1 == LSHIFT_EXPR)
5112 || (code1 == RSHIFT_EXPR && code0 == LSHIFT_EXPR))
5113 && operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1,0), 0)
5114 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0))))
5116 register tree tree01, tree11;
5117 register enum tree_code code01, code11;
5119 tree01 = TREE_OPERAND (arg0, 1);
5120 tree11 = TREE_OPERAND (arg1, 1);
5121 STRIP_NOPS (tree01);
5122 STRIP_NOPS (tree11);
5123 code01 = TREE_CODE (tree01);
5124 code11 = TREE_CODE (tree11);
5125 if (code01 == INTEGER_CST
5126 && code11 == INTEGER_CST
5127 && TREE_INT_CST_HIGH (tree01) == 0
5128 && TREE_INT_CST_HIGH (tree11) == 0
5129 && ((TREE_INT_CST_LOW (tree01) + TREE_INT_CST_LOW (tree11))
5130 == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)))))
5131 return build (LROTATE_EXPR, type, TREE_OPERAND (arg0, 0),
5132 code0 == LSHIFT_EXPR ? tree01 : tree11);
5133 else if (code11 == MINUS_EXPR)
5135 tree tree110, tree111;
5136 tree110 = TREE_OPERAND (tree11, 0);
5137 tree111 = TREE_OPERAND (tree11, 1);
5138 STRIP_NOPS (tree110);
5139 STRIP_NOPS (tree111);
5140 if (TREE_CODE (tree110) == INTEGER_CST
5141 && TREE_INT_CST_HIGH (tree110) == 0
5142 && (TREE_INT_CST_LOW (tree110)
5143 == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0))))
5144 && operand_equal_p (tree01, tree111, 0))
5145 return build ((code0 == LSHIFT_EXPR
5148 type, TREE_OPERAND (arg0, 0), tree01);
5150 else if (code01 == MINUS_EXPR)
5152 tree tree010, tree011;
5153 tree010 = TREE_OPERAND (tree01, 0);
5154 tree011 = TREE_OPERAND (tree01, 1);
5155 STRIP_NOPS (tree010);
5156 STRIP_NOPS (tree011);
5157 if (TREE_CODE (tree010) == INTEGER_CST
5158 && TREE_INT_CST_HIGH (tree010) == 0
5159 && (TREE_INT_CST_LOW (tree010)
5160 == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0))))
5161 && operand_equal_p (tree11, tree011, 0))
5162 return build ((code0 != LSHIFT_EXPR
5165 type, TREE_OPERAND (arg0, 0), tree11);
5173 if (integer_zerop (arg1))
5174 return non_lvalue (convert (type, arg0));
5175 if (integer_all_onesp (arg1))
5176 return fold (build1 (BIT_NOT_EXPR, type, arg0));
5177 /* See if this can be simplified into a rotate first. If that
5178 is unsuccessful we will jump to the association code. */
5183 if (integer_all_onesp (arg1))
5184 return non_lvalue (convert (type, arg0));
5185 if (integer_zerop (arg1))
5186 return omit_one_operand (type, arg1, arg0);
5187 t1 = distribute_bit_expr (code, type, arg0, arg1);
5188 if (t1 != NULL_TREE)
5190 /* Simplify ((int)c & 0x377) into (int)c, if c is unsigned char. */
5191 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == NOP_EXPR
5192 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg1, 0))))
5194 int prec = TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg1, 0)));
5195 if (prec < BITS_PER_WORD && prec < HOST_BITS_PER_WIDE_INT
5196 && (~TREE_INT_CST_LOW (arg0)
5197 & (((HOST_WIDE_INT) 1 << prec) - 1)) == 0)
5198 return build1 (NOP_EXPR, type, TREE_OPERAND (arg1, 0));
5200 if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) == NOP_EXPR
5201 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0))))
5203 int prec = TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)));
5204 if (prec < BITS_PER_WORD && prec < HOST_BITS_PER_WIDE_INT
5205 && (~TREE_INT_CST_LOW (arg1)
5206 & (((HOST_WIDE_INT) 1 << prec) - 1)) == 0)
5207 return build1 (NOP_EXPR, type, TREE_OPERAND (arg0, 0));
5211 case BIT_ANDTC_EXPR:
5212 if (integer_all_onesp (arg0))
5213 return non_lvalue (convert (type, arg1));
5214 if (integer_zerop (arg0))
5215 return omit_one_operand (type, arg0, arg1);
5216 if (TREE_CODE (arg1) == INTEGER_CST)
5218 arg1 = fold (build1 (BIT_NOT_EXPR, type, arg1));
5219 code = BIT_AND_EXPR;
5225 /* In most cases, do nothing with a divide by zero. */
5226 #if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
5227 #ifndef REAL_INFINITY
5228 if (TREE_CODE (arg1) == REAL_CST && real_zerop (arg1))
5231 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
5233 /* In IEEE floating point, x/1 is not equivalent to x for snans.
5234 However, ANSI says we can drop signals, so we can do this anyway. */
5235 if (real_onep (arg1))
5236 return non_lvalue (convert (type, arg0));
5238 /* If ARG1 is a constant, we can convert this to a multiply by the
5239 reciprocal. This does not have the same rounding properties,
5240 so only do this if -ffast-math. We can actually always safely
5241 do it if ARG1 is a power of two, but it's hard to tell if it is
5242 or not in a portable manner. */
5243 if (TREE_CODE (arg1) == REAL_CST)
5246 && 0 != (tem = const_binop (code, build_real (type, dconst1),
5248 return fold (build (MULT_EXPR, type, arg0, tem));
5249 /* Find the reciprocal if optimizing and the result is exact. */
5253 r = TREE_REAL_CST (arg1);
5254 if (exact_real_inverse (TYPE_MODE(TREE_TYPE(arg0)), &r))
5256 tem = build_real (type, r);
5257 return fold (build (MULT_EXPR, type, arg0, tem));
5263 case TRUNC_DIV_EXPR:
5264 case ROUND_DIV_EXPR:
5265 case FLOOR_DIV_EXPR:
5267 case EXACT_DIV_EXPR:
5268 if (integer_onep (arg1))
5269 return non_lvalue (convert (type, arg0));
5270 if (integer_zerop (arg1))
5273 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
5274 operation, EXACT_DIV_EXPR.
5276 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
5277 At one time others generated faster code, it's not clear if they do
5278 after the last round to changes to the DIV code in expmed.c. */
5279 if ((code == CEIL_DIV_EXPR || code == FLOOR_DIV_EXPR)
5280 && multiple_of_p (type, arg0, arg1))
5281 return fold (build (EXACT_DIV_EXPR, type, arg0, arg1));
5283 /* If we have ((a / C1) / C2) where both division are the same type, try
5284 to simplify. First see if C1 * C2 overflows or not. */
5285 if (TREE_CODE (arg0) == code && TREE_CODE (arg1) == INTEGER_CST
5286 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST)
5290 new_divisor = const_binop (MULT_EXPR, TREE_OPERAND (arg0, 1), arg1, 0);
5291 tem = const_binop (FLOOR_DIV_EXPR, new_divisor, arg1, 0);
5293 if (TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1)) == TREE_INT_CST_LOW (tem)
5294 && TREE_INT_CST_HIGH (TREE_OPERAND (arg0, 1)) == TREE_INT_CST_HIGH (tem))
5296 /* If no overflow, divide by C1*C2. */
5297 return fold (build (code, type, TREE_OPERAND (arg0, 0), new_divisor));
5301 /* Look for ((a * C1) / C3) or (((a * C1) + C2) / C3),
5302 where C1 % C3 == 0 or C3 % C1 == 0. We can simplify these
5303 expressions, which often appear in the offsets or sizes of
5304 objects with a varying size. Only deal with positive divisors
5305 and multiplicands. If C2 is negative, we must have C2 % C3 == 0.
5307 Look for NOPs and SAVE_EXPRs inside. */
5309 if (TREE_CODE (arg1) == INTEGER_CST
5310 && tree_int_cst_sgn (arg1) >= 0)
5312 int have_save_expr = 0;
5313 tree c2 = integer_zero_node;
5316 if (TREE_CODE (xarg0) == SAVE_EXPR && SAVE_EXPR_RTL (xarg0) == 0)
5317 have_save_expr = 1, xarg0 = TREE_OPERAND (xarg0, 0);
5321 /* Look inside the dividend and simplify using EXACT_DIV_EXPR
5323 if (TREE_CODE (xarg0) == MULT_EXPR
5324 && multiple_of_p (type, TREE_OPERAND (xarg0, 0), arg1))
5328 t = fold (build (MULT_EXPR, type,
5329 fold (build (EXACT_DIV_EXPR, type,
5330 TREE_OPERAND (xarg0, 0), arg1)),
5331 TREE_OPERAND (xarg0, 1)));
5338 if (TREE_CODE (xarg0) == MULT_EXPR
5339 && multiple_of_p (type, TREE_OPERAND (xarg0, 1), arg1))
5343 t = fold (build (MULT_EXPR, type,
5344 fold (build (EXACT_DIV_EXPR, type,
5345 TREE_OPERAND (xarg0, 1), arg1)),
5346 TREE_OPERAND (xarg0, 0)));
5352 if (TREE_CODE (xarg0) == PLUS_EXPR
5353 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST)
5354 c2 = TREE_OPERAND (xarg0, 1), xarg0 = TREE_OPERAND (xarg0, 0);
5355 else if (TREE_CODE (xarg0) == MINUS_EXPR
5356 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
5357 /* If we are doing this computation unsigned, the negate
5359 && ! TREE_UNSIGNED (type))
5361 c2 = fold (build1 (NEGATE_EXPR, type, TREE_OPERAND (xarg0, 1)));
5362 xarg0 = TREE_OPERAND (xarg0, 0);
5365 if (TREE_CODE (xarg0) == SAVE_EXPR && SAVE_EXPR_RTL (xarg0) == 0)
5366 have_save_expr = 1, xarg0 = TREE_OPERAND (xarg0, 0);
5370 if (TREE_CODE (xarg0) == MULT_EXPR
5371 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
5372 && tree_int_cst_sgn (TREE_OPERAND (xarg0, 1)) >= 0
5373 && (integer_zerop (const_binop (TRUNC_MOD_EXPR,
5374 TREE_OPERAND (xarg0, 1), arg1, 1))
5375 || integer_zerop (const_binop (TRUNC_MOD_EXPR, arg1,
5376 TREE_OPERAND (xarg0, 1), 1)))
5377 && (tree_int_cst_sgn (c2) >= 0
5378 || integer_zerop (const_binop (TRUNC_MOD_EXPR, c2,
5381 tree outer_div = integer_one_node;
5382 tree c1 = TREE_OPERAND (xarg0, 1);
5385 /* If C3 > C1, set them equal and do a divide by
5386 C3/C1 at the end of the operation. */
5387 if (tree_int_cst_lt (c1, c3))
5388 outer_div = const_binop (code, c3, c1, 0), c3 = c1;
5390 /* The result is A * (C1/C3) + (C2/C3). */
5391 t = fold (build (PLUS_EXPR, type,
5392 fold (build (MULT_EXPR, type,
5393 TREE_OPERAND (xarg0, 0),
5394 const_binop (code, c1, c3, 1))),
5395 const_binop (code, c2, c3, 1)));
5397 if (! integer_onep (outer_div))
5398 t = fold (build (code, type, t, convert (type, outer_div)));
5410 case FLOOR_MOD_EXPR:
5411 case ROUND_MOD_EXPR:
5412 case TRUNC_MOD_EXPR:
5413 if (integer_onep (arg1))
5414 return omit_one_operand (type, integer_zero_node, arg0);
5415 if (integer_zerop (arg1))
5418 /* Look for ((a * C1) % C3) or (((a * C1) + C2) % C3),
5419 where C1 % C3 == 0. Handle similarly to the division case,
5420 but don't bother with SAVE_EXPRs. */
5422 if (TREE_CODE (arg1) == INTEGER_CST
5423 && ! integer_zerop (arg1))
5425 tree c2 = integer_zero_node;
5428 if (TREE_CODE (xarg0) == PLUS_EXPR
5429 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST)
5430 c2 = TREE_OPERAND (xarg0, 1), xarg0 = TREE_OPERAND (xarg0, 0);
5431 else if (TREE_CODE (xarg0) == MINUS_EXPR
5432 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
5433 && ! TREE_UNSIGNED (type))
5435 c2 = fold (build1 (NEGATE_EXPR, type, TREE_OPERAND (xarg0, 1)));
5436 xarg0 = TREE_OPERAND (xarg0, 0);
5441 if (TREE_CODE (xarg0) == MULT_EXPR
5442 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
5443 && integer_zerop (const_binop (TRUNC_MOD_EXPR,
5444 TREE_OPERAND (xarg0, 1),
5446 && tree_int_cst_sgn (c2) >= 0)
5447 /* The result is (C2%C3). */
5448 return omit_one_operand (type, const_binop (code, c2, arg1, 1),
5449 TREE_OPERAND (xarg0, 0));
5458 if (integer_zerop (arg1))
5459 return non_lvalue (convert (type, arg0));
5460 /* Since negative shift count is not well-defined,
5461 don't try to compute it in the compiler. */
5462 if (TREE_CODE (arg1) == INTEGER_CST && tree_int_cst_sgn (arg1) < 0)
5464 /* Rewrite an LROTATE_EXPR by a constant into an
5465 RROTATE_EXPR by a new constant. */
5466 if (code == LROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST)
5468 TREE_SET_CODE (t, RROTATE_EXPR);
5469 code = RROTATE_EXPR;
5470 TREE_OPERAND (t, 1) = arg1
5473 convert (TREE_TYPE (arg1),
5474 build_int_2 (GET_MODE_BITSIZE (TYPE_MODE (type)), 0)),
5476 if (tree_int_cst_sgn (arg1) < 0)
5480 /* If we have a rotate of a bit operation with the rotate count and
5481 the second operand of the bit operation both constant,
5482 permute the two operations. */
5483 if (code == RROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST
5484 && (TREE_CODE (arg0) == BIT_AND_EXPR
5485 || TREE_CODE (arg0) == BIT_ANDTC_EXPR
5486 || TREE_CODE (arg0) == BIT_IOR_EXPR
5487 || TREE_CODE (arg0) == BIT_XOR_EXPR)
5488 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST)
5489 return fold (build (TREE_CODE (arg0), type,
5490 fold (build (code, type,
5491 TREE_OPERAND (arg0, 0), arg1)),
5492 fold (build (code, type,
5493 TREE_OPERAND (arg0, 1), arg1))));
5495 /* Two consecutive rotates adding up to the width of the mode can
5497 if (code == RROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST
5498 && TREE_CODE (arg0) == RROTATE_EXPR
5499 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
5500 && TREE_INT_CST_HIGH (arg1) == 0
5501 && TREE_INT_CST_HIGH (TREE_OPERAND (arg0, 1)) == 0
5502 && ((TREE_INT_CST_LOW (arg1)
5503 + TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1)))
5504 == GET_MODE_BITSIZE (TYPE_MODE (type))))
5505 return TREE_OPERAND (arg0, 0);
5510 if (operand_equal_p (arg0, arg1, 0))
5512 if (INTEGRAL_TYPE_P (type)
5513 && operand_equal_p (arg1, TYPE_MIN_VALUE (type), 1))
5514 return omit_one_operand (type, arg1, arg0);
5518 if (operand_equal_p (arg0, arg1, 0))
5520 if (INTEGRAL_TYPE_P (type)
5521 && TYPE_MAX_VALUE (type)
5522 && operand_equal_p (arg1, TYPE_MAX_VALUE (type), 1))
5523 return omit_one_operand (type, arg1, arg0);
5526 case TRUTH_NOT_EXPR:
5527 /* Note that the operand of this must be an int
5528 and its values must be 0 or 1.
5529 ("true" is a fixed value perhaps depending on the language,
5530 but we don't handle values other than 1 correctly yet.) */
5531 tem = invert_truthvalue (arg0);
5532 /* Avoid infinite recursion. */
5533 if (TREE_CODE (tem) == TRUTH_NOT_EXPR)
5535 return convert (type, tem);
5537 case TRUTH_ANDIF_EXPR:
5538 /* Note that the operands of this must be ints
5539 and their values must be 0 or 1.
5540 ("true" is a fixed value perhaps depending on the language.) */
5541 /* If first arg is constant zero, return it. */
5542 if (integer_zerop (arg0))
5544 case TRUTH_AND_EXPR:
5545 /* If either arg is constant true, drop it. */
5546 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
5547 return non_lvalue (arg1);
5548 if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1))
5549 return non_lvalue (arg0);
5550 /* If second arg is constant zero, result is zero, but first arg
5551 must be evaluated. */
5552 if (integer_zerop (arg1))
5553 return omit_one_operand (type, arg1, arg0);
5554 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
5555 case will be handled here. */
5556 if (integer_zerop (arg0))
5557 return omit_one_operand (type, arg0, arg1);
5560 /* We only do these simplifications if we are optimizing. */
5564 /* Check for things like (A || B) && (A || C). We can convert this
5565 to A || (B && C). Note that either operator can be any of the four
5566 truth and/or operations and the transformation will still be
5567 valid. Also note that we only care about order for the
5568 ANDIF and ORIF operators. If B contains side effects, this
5569 might change the truth-value of A. */
5570 if (TREE_CODE (arg0) == TREE_CODE (arg1)
5571 && (TREE_CODE (arg0) == TRUTH_ANDIF_EXPR
5572 || TREE_CODE (arg0) == TRUTH_ORIF_EXPR
5573 || TREE_CODE (arg0) == TRUTH_AND_EXPR
5574 || TREE_CODE (arg0) == TRUTH_OR_EXPR)
5575 && ! TREE_SIDE_EFFECTS (TREE_OPERAND (arg0, 1)))
5577 tree a00 = TREE_OPERAND (arg0, 0);
5578 tree a01 = TREE_OPERAND (arg0, 1);
5579 tree a10 = TREE_OPERAND (arg1, 0);
5580 tree a11 = TREE_OPERAND (arg1, 1);
5581 int commutative = ((TREE_CODE (arg0) == TRUTH_OR_EXPR
5582 || TREE_CODE (arg0) == TRUTH_AND_EXPR)
5583 && (code == TRUTH_AND_EXPR
5584 || code == TRUTH_OR_EXPR));
5586 if (operand_equal_p (a00, a10, 0))
5587 return fold (build (TREE_CODE (arg0), type, a00,
5588 fold (build (code, type, a01, a11))));
5589 else if (commutative && operand_equal_p (a00, a11, 0))
5590 return fold (build (TREE_CODE (arg0), type, a00,
5591 fold (build (code, type, a01, a10))));
5592 else if (commutative && operand_equal_p (a01, a10, 0))
5593 return fold (build (TREE_CODE (arg0), type, a01,
5594 fold (build (code, type, a00, a11))));
5596 /* This case if tricky because we must either have commutative
5597 operators or else A10 must not have side-effects. */
5599 else if ((commutative || ! TREE_SIDE_EFFECTS (a10))
5600 && operand_equal_p (a01, a11, 0))
5601 return fold (build (TREE_CODE (arg0), type,
5602 fold (build (code, type, a00, a10)),
5606 /* See if we can build a range comparison. */
5607 if (0 != (tem = fold_range_test (t)))
5610 /* Check for the possibility of merging component references. If our
5611 lhs is another similar operation, try to merge its rhs with our
5612 rhs. Then try to merge our lhs and rhs. */
5613 if (TREE_CODE (arg0) == code
5614 && 0 != (tem = fold_truthop (code, type,
5615 TREE_OPERAND (arg0, 1), arg1)))
5616 return fold (build (code, type, TREE_OPERAND (arg0, 0), tem));
5618 if ((tem = fold_truthop (code, type, arg0, arg1)) != 0)
5623 case TRUTH_ORIF_EXPR:
5624 /* Note that the operands of this must be ints
5625 and their values must be 0 or true.
5626 ("true" is a fixed value perhaps depending on the language.) */
5627 /* If first arg is constant true, return it. */
5628 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
5631 /* If either arg is constant zero, drop it. */
5632 if (TREE_CODE (arg0) == INTEGER_CST && integer_zerop (arg0))
5633 return non_lvalue (arg1);
5634 if (TREE_CODE (arg1) == INTEGER_CST && integer_zerop (arg1))
5635 return non_lvalue (arg0);
5636 /* If second arg is constant true, result is true, but we must
5637 evaluate first arg. */
5638 if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1))
5639 return omit_one_operand (type, arg1, arg0);
5640 /* Likewise for first arg, but note this only occurs here for
5642 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
5643 return omit_one_operand (type, arg0, arg1);
5646 case TRUTH_XOR_EXPR:
5647 /* If either arg is constant zero, drop it. */
5648 if (integer_zerop (arg0))
5649 return non_lvalue (arg1);
5650 if (integer_zerop (arg1))
5651 return non_lvalue (arg0);
5652 /* If either arg is constant true, this is a logical inversion. */
5653 if (integer_onep (arg0))
5654 return non_lvalue (invert_truthvalue (arg1));
5655 if (integer_onep (arg1))
5656 return non_lvalue (invert_truthvalue (arg0));
5665 /* If one arg is a constant integer, put it last. */
5666 if (TREE_CODE (arg0) == INTEGER_CST
5667 && TREE_CODE (arg1) != INTEGER_CST)
5669 TREE_OPERAND (t, 0) = arg1;
5670 TREE_OPERAND (t, 1) = arg0;
5671 arg0 = TREE_OPERAND (t, 0);
5672 arg1 = TREE_OPERAND (t, 1);
5673 code = swap_tree_comparison (code);
5674 TREE_SET_CODE (t, code);
5677 /* Convert foo++ == CONST into ++foo == CONST + INCR.
5678 First, see if one arg is constant; find the constant arg
5679 and the other one. */
5681 tree constop = 0, varop = NULL_TREE;
5682 int constopnum = -1;
5684 if (TREE_CONSTANT (arg1))
5685 constopnum = 1, constop = arg1, varop = arg0;
5686 if (TREE_CONSTANT (arg0))
5687 constopnum = 0, constop = arg0, varop = arg1;
5689 if (constop && TREE_CODE (varop) == POSTINCREMENT_EXPR)
5691 /* This optimization is invalid for ordered comparisons
5692 if CONST+INCR overflows or if foo+incr might overflow.
5693 This optimization is invalid for floating point due to rounding.
5694 For pointer types we assume overflow doesn't happen. */
5695 if (POINTER_TYPE_P (TREE_TYPE (varop))
5696 || (! FLOAT_TYPE_P (TREE_TYPE (varop))
5697 && (code == EQ_EXPR || code == NE_EXPR)))
5700 = fold (build (PLUS_EXPR, TREE_TYPE (varop),
5701 constop, TREE_OPERAND (varop, 1)));
5702 TREE_SET_CODE (varop, PREINCREMENT_EXPR);
5704 /* If VAROP is a reference to a bitfield, we must mask
5705 the constant by the width of the field. */
5706 if (TREE_CODE (TREE_OPERAND (varop, 0)) == COMPONENT_REF
5707 && DECL_BIT_FIELD(TREE_OPERAND
5708 (TREE_OPERAND (varop, 0), 1)))
5711 = TREE_INT_CST_LOW (DECL_SIZE
5713 (TREE_OPERAND (varop, 0), 1)));
5714 tree mask, unsigned_type;
5716 tree folded_compare;
5718 /* First check whether the comparison would come out
5719 always the same. If we don't do that we would
5720 change the meaning with the masking. */
5721 if (constopnum == 0)
5722 folded_compare = fold (build (code, type, constop,
5723 TREE_OPERAND (varop, 0)));
5725 folded_compare = fold (build (code, type,
5726 TREE_OPERAND (varop, 0),
5728 if (integer_zerop (folded_compare)
5729 || integer_onep (folded_compare))
5730 return omit_one_operand (type, folded_compare, varop);
5732 unsigned_type = type_for_size (size, 1);
5733 precision = TYPE_PRECISION (unsigned_type);
5734 mask = build_int_2 (~0, ~0);
5735 TREE_TYPE (mask) = unsigned_type;
5736 force_fit_type (mask, 0);
5737 mask = const_binop (RSHIFT_EXPR, mask,
5738 size_int (precision - size), 0);
5739 newconst = fold (build (BIT_AND_EXPR,
5740 TREE_TYPE (varop), newconst,
5741 convert (TREE_TYPE (varop),
5746 t = build (code, type, TREE_OPERAND (t, 0),
5747 TREE_OPERAND (t, 1));
5748 TREE_OPERAND (t, constopnum) = newconst;
5752 else if (constop && TREE_CODE (varop) == POSTDECREMENT_EXPR)
5754 if (POINTER_TYPE_P (TREE_TYPE (varop))
5755 || (! FLOAT_TYPE_P (TREE_TYPE (varop))
5756 && (code == EQ_EXPR || code == NE_EXPR)))
5759 = fold (build (MINUS_EXPR, TREE_TYPE (varop),
5760 constop, TREE_OPERAND (varop, 1)));
5761 TREE_SET_CODE (varop, PREDECREMENT_EXPR);
5763 if (TREE_CODE (TREE_OPERAND (varop, 0)) == COMPONENT_REF
5764 && DECL_BIT_FIELD(TREE_OPERAND
5765 (TREE_OPERAND (varop, 0), 1)))
5768 = TREE_INT_CST_LOW (DECL_SIZE
5770 (TREE_OPERAND (varop, 0), 1)));
5771 tree mask, unsigned_type;
5773 tree folded_compare;
5775 if (constopnum == 0)
5776 folded_compare = fold (build (code, type, constop,
5777 TREE_OPERAND (varop, 0)));
5779 folded_compare = fold (build (code, type,
5780 TREE_OPERAND (varop, 0),
5782 if (integer_zerop (folded_compare)
5783 || integer_onep (folded_compare))
5784 return omit_one_operand (type, folded_compare, varop);
5786 unsigned_type = type_for_size (size, 1);
5787 precision = TYPE_PRECISION (unsigned_type);
5788 mask = build_int_2 (~0, ~0);
5789 TREE_TYPE (mask) = TREE_TYPE (varop);
5790 force_fit_type (mask, 0);
5791 mask = const_binop (RSHIFT_EXPR, mask,
5792 size_int (precision - size), 0);
5793 newconst = fold (build (BIT_AND_EXPR,
5794 TREE_TYPE (varop), newconst,
5795 convert (TREE_TYPE (varop),
5800 t = build (code, type, TREE_OPERAND (t, 0),
5801 TREE_OPERAND (t, 1));
5802 TREE_OPERAND (t, constopnum) = newconst;
5808 /* Change X >= CST to X > (CST - 1) if CST is positive. */
5809 if (TREE_CODE (arg1) == INTEGER_CST
5810 && TREE_CODE (arg0) != INTEGER_CST
5811 && tree_int_cst_sgn (arg1) > 0)
5813 switch (TREE_CODE (t))
5817 arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
5818 t = build (code, type, TREE_OPERAND (t, 0), arg1);
5823 arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
5824 t = build (code, type, TREE_OPERAND (t, 0), arg1);
5832 /* If this is an EQ or NE comparison with zero and ARG0 is
5833 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
5834 two operations, but the latter can be done in one less insn
5835 on machines that have only two-operand insns or on which a
5836 constant cannot be the first operand. */
5837 if (integer_zerop (arg1) && (code == EQ_EXPR || code == NE_EXPR)
5838 && TREE_CODE (arg0) == BIT_AND_EXPR)
5840 if (TREE_CODE (TREE_OPERAND (arg0, 0)) == LSHIFT_EXPR
5841 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 0), 0)))
5843 fold (build (code, type,
5844 build (BIT_AND_EXPR, TREE_TYPE (arg0),
5846 TREE_TYPE (TREE_OPERAND (arg0, 0)),
5847 TREE_OPERAND (arg0, 1),
5848 TREE_OPERAND (TREE_OPERAND (arg0, 0), 1)),
5849 convert (TREE_TYPE (arg0),
5852 else if (TREE_CODE (TREE_OPERAND (arg0, 1)) == LSHIFT_EXPR
5853 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 1), 0)))
5855 fold (build (code, type,
5856 build (BIT_AND_EXPR, TREE_TYPE (arg0),
5858 TREE_TYPE (TREE_OPERAND (arg0, 1)),
5859 TREE_OPERAND (arg0, 0),
5860 TREE_OPERAND (TREE_OPERAND (arg0, 1), 1)),
5861 convert (TREE_TYPE (arg0),
5866 /* If this is an NE or EQ comparison of zero against the result of a
5867 signed MOD operation whose second operand is a power of 2, make
5868 the MOD operation unsigned since it is simpler and equivalent. */
5869 if ((code == NE_EXPR || code == EQ_EXPR)
5870 && integer_zerop (arg1)
5871 && ! TREE_UNSIGNED (TREE_TYPE (arg0))
5872 && (TREE_CODE (arg0) == TRUNC_MOD_EXPR
5873 || TREE_CODE (arg0) == CEIL_MOD_EXPR
5874 || TREE_CODE (arg0) == FLOOR_MOD_EXPR
5875 || TREE_CODE (arg0) == ROUND_MOD_EXPR)
5876 && integer_pow2p (TREE_OPERAND (arg0, 1)))
5878 tree newtype = unsigned_type (TREE_TYPE (arg0));
5879 tree newmod = build (TREE_CODE (arg0), newtype,
5880 convert (newtype, TREE_OPERAND (arg0, 0)),
5881 convert (newtype, TREE_OPERAND (arg0, 1)));
5883 return build (code, type, newmod, convert (newtype, arg1));
5886 /* If this is an NE comparison of zero with an AND of one, remove the
5887 comparison since the AND will give the correct value. */
5888 if (code == NE_EXPR && integer_zerop (arg1)
5889 && TREE_CODE (arg0) == BIT_AND_EXPR
5890 && integer_onep (TREE_OPERAND (arg0, 1)))
5891 return convert (type, arg0);
5893 /* If we have (A & C) == C where C is a power of 2, convert this into
5894 (A & C) != 0. Similarly for NE_EXPR. */
5895 if ((code == EQ_EXPR || code == NE_EXPR)
5896 && TREE_CODE (arg0) == BIT_AND_EXPR
5897 && integer_pow2p (TREE_OPERAND (arg0, 1))
5898 && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0))
5899 return build (code == EQ_EXPR ? NE_EXPR : EQ_EXPR, type,
5900 arg0, integer_zero_node);
5902 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
5903 and similarly for >= into !=. */
5904 if ((code == LT_EXPR || code == GE_EXPR)
5905 && TREE_UNSIGNED (TREE_TYPE (arg0))
5906 && TREE_CODE (arg1) == LSHIFT_EXPR
5907 && integer_onep (TREE_OPERAND (arg1, 0)))
5908 return build (code == LT_EXPR ? EQ_EXPR : NE_EXPR, type,
5909 build (RSHIFT_EXPR, TREE_TYPE (arg0), arg0,
5910 TREE_OPERAND (arg1, 1)),
5911 convert (TREE_TYPE (arg0), integer_zero_node));
5913 else if ((code == LT_EXPR || code == GE_EXPR)
5914 && TREE_UNSIGNED (TREE_TYPE (arg0))
5915 && (TREE_CODE (arg1) == NOP_EXPR
5916 || TREE_CODE (arg1) == CONVERT_EXPR)
5917 && TREE_CODE (TREE_OPERAND (arg1, 0)) == LSHIFT_EXPR
5918 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg1, 0), 0)))
5920 build (code == LT_EXPR ? EQ_EXPR : NE_EXPR, type,
5921 convert (TREE_TYPE (arg0),
5922 build (RSHIFT_EXPR, TREE_TYPE (arg0), arg0,
5923 TREE_OPERAND (TREE_OPERAND (arg1, 0), 1))),
5924 convert (TREE_TYPE (arg0), integer_zero_node));
5926 /* Simplify comparison of something with itself. (For IEEE
5927 floating-point, we can only do some of these simplifications.) */
5928 if (operand_equal_p (arg0, arg1, 0))
5935 if (INTEGRAL_TYPE_P (TREE_TYPE (arg0)))
5936 return constant_boolean_node (1, type);
5938 TREE_SET_CODE (t, code);
5942 /* For NE, we can only do this simplification if integer. */
5943 if (! INTEGRAL_TYPE_P (TREE_TYPE (arg0)))
5945 /* ... fall through ... */
5948 return constant_boolean_node (0, type);
5954 /* An unsigned comparison against 0 can be simplified. */
5955 if (integer_zerop (arg1)
5956 && (INTEGRAL_TYPE_P (TREE_TYPE (arg1))
5957 || POINTER_TYPE_P (TREE_TYPE (arg1)))
5958 && TREE_UNSIGNED (TREE_TYPE (arg1)))
5960 switch (TREE_CODE (t))
5964 TREE_SET_CODE (t, NE_EXPR);
5968 TREE_SET_CODE (t, EQ_EXPR);
5971 return omit_one_operand (type,
5972 convert (type, integer_one_node),
5975 return omit_one_operand (type,
5976 convert (type, integer_zero_node),
5983 /* An unsigned <= 0x7fffffff can be simplified. */
5985 int width = TYPE_PRECISION (TREE_TYPE (arg1));
5986 if (TREE_CODE (arg1) == INTEGER_CST
5987 && ! TREE_CONSTANT_OVERFLOW (arg1)
5988 && width <= HOST_BITS_PER_WIDE_INT
5989 && TREE_INT_CST_LOW (arg1) == ((HOST_WIDE_INT) 1 << (width - 1)) - 1
5990 && TREE_INT_CST_HIGH (arg1) == 0
5991 && (INTEGRAL_TYPE_P (TREE_TYPE (arg1))
5992 || POINTER_TYPE_P (TREE_TYPE (arg1)))
5993 && TREE_UNSIGNED (TREE_TYPE (arg1)))
5995 switch (TREE_CODE (t))
5998 return fold (build (GE_EXPR, type,
5999 convert (signed_type (TREE_TYPE (arg0)),
6001 convert (signed_type (TREE_TYPE (arg1)),
6002 integer_zero_node)));
6004 return fold (build (LT_EXPR, type,
6005 convert (signed_type (TREE_TYPE (arg0)),
6007 convert (signed_type (TREE_TYPE (arg1)),
6008 integer_zero_node)));
6015 /* If we are comparing an expression that just has comparisons
6016 of two integer values, arithmetic expressions of those comparisons,
6017 and constants, we can simplify it. There are only three cases
6018 to check: the two values can either be equal, the first can be
6019 greater, or the second can be greater. Fold the expression for
6020 those three values. Since each value must be 0 or 1, we have
6021 eight possibilities, each of which corresponds to the constant 0
6022 or 1 or one of the six possible comparisons.
6024 This handles common cases like (a > b) == 0 but also handles
6025 expressions like ((x > y) - (y > x)) > 0, which supposedly
6026 occur in macroized code. */
6028 if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) != INTEGER_CST)
6030 tree cval1 = 0, cval2 = 0;
6033 if (twoval_comparison_p (arg0, &cval1, &cval2, &save_p)
6034 /* Don't handle degenerate cases here; they should already
6035 have been handled anyway. */
6036 && cval1 != 0 && cval2 != 0
6037 && ! (TREE_CONSTANT (cval1) && TREE_CONSTANT (cval2))
6038 && TREE_TYPE (cval1) == TREE_TYPE (cval2)
6039 && INTEGRAL_TYPE_P (TREE_TYPE (cval1))
6040 && TYPE_MAX_VALUE (TREE_TYPE (cval1))
6041 && TYPE_MAX_VALUE (TREE_TYPE (cval2))
6042 && ! operand_equal_p (TYPE_MIN_VALUE (TREE_TYPE (cval1)),
6043 TYPE_MAX_VALUE (TREE_TYPE (cval2)), 0))
6045 tree maxval = TYPE_MAX_VALUE (TREE_TYPE (cval1));
6046 tree minval = TYPE_MIN_VALUE (TREE_TYPE (cval1));
6048 /* We can't just pass T to eval_subst in case cval1 or cval2
6049 was the same as ARG1. */
6052 = fold (build (code, type,
6053 eval_subst (arg0, cval1, maxval, cval2, minval),
6056 = fold (build (code, type,
6057 eval_subst (arg0, cval1, maxval, cval2, maxval),
6060 = fold (build (code, type,
6061 eval_subst (arg0, cval1, minval, cval2, maxval),
6064 /* All three of these results should be 0 or 1. Confirm they
6065 are. Then use those values to select the proper code
6068 if ((integer_zerop (high_result)
6069 || integer_onep (high_result))
6070 && (integer_zerop (equal_result)
6071 || integer_onep (equal_result))
6072 && (integer_zerop (low_result)
6073 || integer_onep (low_result)))
6075 /* Make a 3-bit mask with the high-order bit being the
6076 value for `>', the next for '=', and the low for '<'. */
6077 switch ((integer_onep (high_result) * 4)
6078 + (integer_onep (equal_result) * 2)
6079 + integer_onep (low_result))
6083 return omit_one_operand (type, integer_zero_node, arg0);
6104 return omit_one_operand (type, integer_one_node, arg0);
6107 t = build (code, type, cval1, cval2);
6109 return save_expr (t);
6116 /* If this is a comparison of a field, we may be able to simplify it. */
6117 if ((TREE_CODE (arg0) == COMPONENT_REF
6118 || TREE_CODE (arg0) == BIT_FIELD_REF)
6119 && (code == EQ_EXPR || code == NE_EXPR)
6120 /* Handle the constant case even without -O
6121 to make sure the warnings are given. */
6122 && (optimize || TREE_CODE (arg1) == INTEGER_CST))
6124 t1 = optimize_bit_field_compare (code, type, arg0, arg1);
6128 /* If this is a comparison of complex values and either or both sides
6129 are a COMPLEX_EXPR or COMPLEX_CST, it is best to split up the
6130 comparisons and join them with a TRUTH_ANDIF_EXPR or TRUTH_ORIF_EXPR.
6131 This may prevent needless evaluations. */
6132 if ((code == EQ_EXPR || code == NE_EXPR)
6133 && TREE_CODE (TREE_TYPE (arg0)) == COMPLEX_TYPE
6134 && (TREE_CODE (arg0) == COMPLEX_EXPR
6135 || TREE_CODE (arg1) == COMPLEX_EXPR
6136 || TREE_CODE (arg0) == COMPLEX_CST
6137 || TREE_CODE (arg1) == COMPLEX_CST))
6139 tree subtype = TREE_TYPE (TREE_TYPE (arg0));
6140 tree real0, imag0, real1, imag1;
6142 arg0 = save_expr (arg0);
6143 arg1 = save_expr (arg1);
6144 real0 = fold (build1 (REALPART_EXPR, subtype, arg0));
6145 imag0 = fold (build1 (IMAGPART_EXPR, subtype, arg0));
6146 real1 = fold (build1 (REALPART_EXPR, subtype, arg1));
6147 imag1 = fold (build1 (IMAGPART_EXPR, subtype, arg1));
6149 return fold (build ((code == EQ_EXPR ? TRUTH_ANDIF_EXPR
6152 fold (build (code, type, real0, real1)),
6153 fold (build (code, type, imag0, imag1))));
6156 /* From here on, the only cases we handle are when the result is
6157 known to be a constant.
6159 To compute GT, swap the arguments and do LT.
6160 To compute GE, do LT and invert the result.
6161 To compute LE, swap the arguments, do LT and invert the result.
6162 To compute NE, do EQ and invert the result.
6164 Therefore, the code below must handle only EQ and LT. */
6166 if (code == LE_EXPR || code == GT_EXPR)
6168 tem = arg0, arg0 = arg1, arg1 = tem;
6169 code = swap_tree_comparison (code);
6172 /* Note that it is safe to invert for real values here because we
6173 will check below in the one case that it matters. */
6176 if (code == NE_EXPR || code == GE_EXPR)
6179 code = invert_tree_comparison (code);
6182 /* Compute a result for LT or EQ if args permit;
6183 otherwise return T. */
6184 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST)
6186 if (code == EQ_EXPR)
6187 t1 = build_int_2 ((TREE_INT_CST_LOW (arg0)
6188 == TREE_INT_CST_LOW (arg1))
6189 && (TREE_INT_CST_HIGH (arg0)
6190 == TREE_INT_CST_HIGH (arg1)),
6193 t1 = build_int_2 ((TREE_UNSIGNED (TREE_TYPE (arg0))
6194 ? INT_CST_LT_UNSIGNED (arg0, arg1)
6195 : INT_CST_LT (arg0, arg1)),
6199 #if 0 /* This is no longer useful, but breaks some real code. */
6200 /* Assume a nonexplicit constant cannot equal an explicit one,
6201 since such code would be undefined anyway.
6202 Exception: on sysvr4, using #pragma weak,
6203 a label can come out as 0. */
6204 else if (TREE_CODE (arg1) == INTEGER_CST
6205 && !integer_zerop (arg1)
6206 && TREE_CONSTANT (arg0)
6207 && TREE_CODE (arg0) == ADDR_EXPR
6209 t1 = build_int_2 (0, 0);
6211 /* Two real constants can be compared explicitly. */
6212 else if (TREE_CODE (arg0) == REAL_CST && TREE_CODE (arg1) == REAL_CST)
6214 /* If either operand is a NaN, the result is false with two
6215 exceptions: First, an NE_EXPR is true on NaNs, but that case
6216 is already handled correctly since we will be inverting the
6217 result for NE_EXPR. Second, if we had inverted a LE_EXPR
6218 or a GE_EXPR into a LT_EXPR, we must return true so that it
6219 will be inverted into false. */
6221 if (REAL_VALUE_ISNAN (TREE_REAL_CST (arg0))
6222 || REAL_VALUE_ISNAN (TREE_REAL_CST (arg1)))
6223 t1 = build_int_2 (invert && code == LT_EXPR, 0);
6225 else if (code == EQ_EXPR)
6226 t1 = build_int_2 (REAL_VALUES_EQUAL (TREE_REAL_CST (arg0),
6227 TREE_REAL_CST (arg1)),
6230 t1 = build_int_2 (REAL_VALUES_LESS (TREE_REAL_CST (arg0),
6231 TREE_REAL_CST (arg1)),
6235 if (t1 == NULL_TREE)
6239 TREE_INT_CST_LOW (t1) ^= 1;
6241 TREE_TYPE (t1) = type;
6242 if (TREE_CODE (type) == BOOLEAN_TYPE)
6243 return truthvalue_conversion (t1);
6247 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
6248 so all simple results must be passed through pedantic_non_lvalue. */
6249 if (TREE_CODE (arg0) == INTEGER_CST)
6250 return pedantic_non_lvalue
6251 (TREE_OPERAND (t, (integer_zerop (arg0) ? 2 : 1)));
6252 else if (operand_equal_p (arg1, TREE_OPERAND (expr, 2), 0))
6253 return pedantic_omit_one_operand (type, arg1, arg0);
6255 /* If the second operand is zero, invert the comparison and swap
6256 the second and third operands. Likewise if the second operand
6257 is constant and the third is not or if the third operand is
6258 equivalent to the first operand of the comparison. */
6260 if (integer_zerop (arg1)
6261 || (TREE_CONSTANT (arg1) && ! TREE_CONSTANT (TREE_OPERAND (t, 2)))
6262 || (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
6263 && operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0),
6264 TREE_OPERAND (t, 2),
6265 TREE_OPERAND (arg0, 1))))
6267 /* See if this can be inverted. If it can't, possibly because
6268 it was a floating-point inequality comparison, don't do
6270 tem = invert_truthvalue (arg0);
6272 if (TREE_CODE (tem) != TRUTH_NOT_EXPR)
6274 t = build (code, type, tem,
6275 TREE_OPERAND (t, 2), TREE_OPERAND (t, 1));
6277 /* arg1 should be the first argument of the new T. */
6278 arg1 = TREE_OPERAND (t, 1);
6283 /* If we have A op B ? A : C, we may be able to convert this to a
6284 simpler expression, depending on the operation and the values
6285 of B and C. IEEE floating point prevents this though,
6286 because A or B might be -0.0 or a NaN. */
6288 if (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
6289 && (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
6290 || ! FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg0, 0)))
6292 && operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0),
6293 arg1, TREE_OPERAND (arg0, 1)))
6295 tree arg2 = TREE_OPERAND (t, 2);
6296 enum tree_code comp_code = TREE_CODE (arg0);
6300 /* If we have A op 0 ? A : -A, this is A, -A, abs (A), or abs (-A),
6301 depending on the comparison operation. */
6302 if ((FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg0, 1)))
6303 ? real_zerop (TREE_OPERAND (arg0, 1))
6304 : integer_zerop (TREE_OPERAND (arg0, 1)))
6305 && TREE_CODE (arg2) == NEGATE_EXPR
6306 && operand_equal_p (TREE_OPERAND (arg2, 0), arg1, 0))
6310 return pedantic_non_lvalue
6311 (fold (build1 (NEGATE_EXPR, type, arg1)));
6313 return pedantic_non_lvalue (convert (type, arg1));
6316 if (TREE_UNSIGNED (TREE_TYPE (arg1)))
6317 arg1 = convert (signed_type (TREE_TYPE (arg1)), arg1);
6318 return pedantic_non_lvalue
6319 (convert (type, fold (build1 (ABS_EXPR,
6320 TREE_TYPE (arg1), arg1))));
6323 if (TREE_UNSIGNED (TREE_TYPE (arg1)))
6324 arg1 = convert (signed_type (TREE_TYPE (arg1)), arg1);
6325 return pedantic_non_lvalue
6326 (fold (build1 (NEGATE_EXPR, type,
6328 fold (build1 (ABS_EXPR,
6335 /* If this is A != 0 ? A : 0, this is simply A. For ==, it is
6338 if (integer_zerop (TREE_OPERAND (arg0, 1)) && integer_zerop (arg2))
6340 if (comp_code == NE_EXPR)
6341 return pedantic_non_lvalue (convert (type, arg1));
6342 else if (comp_code == EQ_EXPR)
6343 return pedantic_non_lvalue (convert (type, integer_zero_node));
6346 /* If this is A op B ? A : B, this is either A, B, min (A, B),
6347 or max (A, B), depending on the operation. */
6349 if (operand_equal_for_comparison_p (TREE_OPERAND (arg0, 1),
6350 arg2, TREE_OPERAND (arg0, 0)))
6352 tree comp_op0 = TREE_OPERAND (arg0, 0);
6353 tree comp_op1 = TREE_OPERAND (arg0, 1);
6354 tree comp_type = TREE_TYPE (comp_op0);
6359 return pedantic_non_lvalue (convert (type, arg2));
6361 return pedantic_non_lvalue (convert (type, arg1));
6364 /* In C++ a ?: expression can be an lvalue, so put the
6365 operand which will be used if they are equal first
6366 so that we can convert this back to the
6367 corresponding COND_EXPR. */
6368 return pedantic_non_lvalue
6369 (convert (type, (fold (build (MIN_EXPR, comp_type,
6370 (comp_code == LE_EXPR
6371 ? comp_op0 : comp_op1),
6372 (comp_code == LE_EXPR
6373 ? comp_op1 : comp_op0))))));
6377 return pedantic_non_lvalue
6378 (convert (type, fold (build (MAX_EXPR, comp_type,
6379 (comp_code == GE_EXPR
6380 ? comp_op0 : comp_op1),
6381 (comp_code == GE_EXPR
6382 ? comp_op1 : comp_op0)))));
6389 /* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
6390 we might still be able to simplify this. For example,
6391 if C1 is one less or one more than C2, this might have started
6392 out as a MIN or MAX and been transformed by this function.
6393 Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */
6395 if (INTEGRAL_TYPE_P (type)
6396 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
6397 && TREE_CODE (arg2) == INTEGER_CST)
6401 /* We can replace A with C1 in this case. */
6402 arg1 = convert (type, TREE_OPERAND (arg0, 1));
6403 t = build (code, type, TREE_OPERAND (t, 0), arg1,
6404 TREE_OPERAND (t, 2));
6408 /* If C1 is C2 + 1, this is min(A, C2). */
6409 if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type), 1)
6410 && operand_equal_p (TREE_OPERAND (arg0, 1),
6411 const_binop (PLUS_EXPR, arg2,
6412 integer_one_node, 0), 1))
6413 return pedantic_non_lvalue
6414 (fold (build (MIN_EXPR, type, arg1, arg2)));
6418 /* If C1 is C2 - 1, this is min(A, C2). */
6419 if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type), 1)
6420 && operand_equal_p (TREE_OPERAND (arg0, 1),
6421 const_binop (MINUS_EXPR, arg2,
6422 integer_one_node, 0), 1))
6423 return pedantic_non_lvalue
6424 (fold (build (MIN_EXPR, type, arg1, arg2)));
6428 /* If C1 is C2 - 1, this is max(A, C2). */
6429 if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type), 1)
6430 && operand_equal_p (TREE_OPERAND (arg0, 1),
6431 const_binop (MINUS_EXPR, arg2,
6432 integer_one_node, 0), 1))
6433 return pedantic_non_lvalue
6434 (fold (build (MAX_EXPR, type, arg1, arg2)));
6438 /* If C1 is C2 + 1, this is max(A, C2). */
6439 if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type), 1)
6440 && operand_equal_p (TREE_OPERAND (arg0, 1),
6441 const_binop (PLUS_EXPR, arg2,
6442 integer_one_node, 0), 1))
6443 return pedantic_non_lvalue
6444 (fold (build (MAX_EXPR, type, arg1, arg2)));
6453 /* If the second operand is simpler than the third, swap them
6454 since that produces better jump optimization results. */
6455 if ((TREE_CONSTANT (arg1) || TREE_CODE_CLASS (TREE_CODE (arg1)) == 'd'
6456 || TREE_CODE (arg1) == SAVE_EXPR)
6457 && ! (TREE_CONSTANT (TREE_OPERAND (t, 2))
6458 || TREE_CODE_CLASS (TREE_CODE (TREE_OPERAND (t, 2))) == 'd'
6459 || TREE_CODE (TREE_OPERAND (t, 2)) == SAVE_EXPR))
6461 /* See if this can be inverted. If it can't, possibly because
6462 it was a floating-point inequality comparison, don't do
6464 tem = invert_truthvalue (arg0);
6466 if (TREE_CODE (tem) != TRUTH_NOT_EXPR)
6468 t = build (code, type, tem,
6469 TREE_OPERAND (t, 2), TREE_OPERAND (t, 1));
6471 /* arg1 should be the first argument of the new T. */
6472 arg1 = TREE_OPERAND (t, 1);
6477 /* Convert A ? 1 : 0 to simply A. */
6478 if (integer_onep (TREE_OPERAND (t, 1))
6479 && integer_zerop (TREE_OPERAND (t, 2))
6480 /* If we try to convert TREE_OPERAND (t, 0) to our type, the
6481 call to fold will try to move the conversion inside
6482 a COND, which will recurse. In that case, the COND_EXPR
6483 is probably the best choice, so leave it alone. */
6484 && type == TREE_TYPE (arg0))
6485 return pedantic_non_lvalue (arg0);
6487 /* Look for expressions of the form A & 2 ? 2 : 0. The result of this
6488 operation is simply A & 2. */
6490 if (integer_zerop (TREE_OPERAND (t, 2))
6491 && TREE_CODE (arg0) == NE_EXPR
6492 && integer_zerop (TREE_OPERAND (arg0, 1))
6493 && integer_pow2p (arg1)
6494 && TREE_CODE (TREE_OPERAND (arg0, 0)) == BIT_AND_EXPR
6495 && operand_equal_p (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1),
6497 return pedantic_non_lvalue (convert (type, TREE_OPERAND (arg0, 0)));
6502 /* When pedantic, a compound expression can be neither an lvalue
6503 nor an integer constant expression. */
6504 if (TREE_SIDE_EFFECTS (arg0) || pedantic)
6506 /* Don't let (0, 0) be null pointer constant. */
6507 if (integer_zerop (arg1))
6508 return build1 (NOP_EXPR, TREE_TYPE (arg1), arg1);
6513 return build_complex (type, arg0, arg1);
6517 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
6519 else if (TREE_CODE (arg0) == COMPLEX_EXPR)
6520 return omit_one_operand (type, TREE_OPERAND (arg0, 0),
6521 TREE_OPERAND (arg0, 1));
6522 else if (TREE_CODE (arg0) == COMPLEX_CST)
6523 return TREE_REALPART (arg0);
6524 else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
6525 return fold (build (TREE_CODE (arg0), type,
6526 fold (build1 (REALPART_EXPR, type,
6527 TREE_OPERAND (arg0, 0))),
6528 fold (build1 (REALPART_EXPR,
6529 type, TREE_OPERAND (arg0, 1)))));
6533 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
6534 return convert (type, integer_zero_node);
6535 else if (TREE_CODE (arg0) == COMPLEX_EXPR)
6536 return omit_one_operand (type, TREE_OPERAND (arg0, 1),
6537 TREE_OPERAND (arg0, 0));
6538 else if (TREE_CODE (arg0) == COMPLEX_CST)
6539 return TREE_IMAGPART (arg0);
6540 else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
6541 return fold (build (TREE_CODE (arg0), type,
6542 fold (build1 (IMAGPART_EXPR, type,
6543 TREE_OPERAND (arg0, 0))),
6544 fold (build1 (IMAGPART_EXPR, type,
6545 TREE_OPERAND (arg0, 1)))));
6548 /* Pull arithmetic ops out of the CLEANUP_POINT_EXPR where
6550 case CLEANUP_POINT_EXPR:
6551 if (! has_cleanups (arg0))
6552 return TREE_OPERAND (t, 0);
6555 enum tree_code code0 = TREE_CODE (arg0);
6556 int kind0 = TREE_CODE_CLASS (code0);
6557 tree arg00 = TREE_OPERAND (arg0, 0);
6560 if (kind0 == '1' || code0 == TRUTH_NOT_EXPR)
6561 return fold (build1 (code0, type,
6562 fold (build1 (CLEANUP_POINT_EXPR,
6563 TREE_TYPE (arg00), arg00))));
6565 if (kind0 == '<' || kind0 == '2'
6566 || code0 == TRUTH_ANDIF_EXPR || code0 == TRUTH_ORIF_EXPR
6567 || code0 == TRUTH_AND_EXPR || code0 == TRUTH_OR_EXPR
6568 || code0 == TRUTH_XOR_EXPR)
6570 arg01 = TREE_OPERAND (arg0, 1);
6572 if (TREE_CONSTANT (arg00)
6573 || ((code0 == TRUTH_ANDIF_EXPR || code0 == TRUTH_ORIF_EXPR)
6574 && ! has_cleanups (arg00)))
6575 return fold (build (code0, type, arg00,
6576 fold (build1 (CLEANUP_POINT_EXPR,
6577 TREE_TYPE (arg01), arg01))));
6579 if (TREE_CONSTANT (arg01))
6580 return fold (build (code0, type,
6581 fold (build1 (CLEANUP_POINT_EXPR,
6582 TREE_TYPE (arg00), arg00)),
6591 } /* switch (code) */
6594 /* Determine if first argument is a multiple of second argument. Return 0 if
6595 it is not, or we cannot easily determined it to be.
6597 An example of the sort of thing we care about (at this point; this routine
6598 could surely be made more general, and expanded to do what the *_DIV_EXPR's
6599 fold cases do now) is discovering that
6601 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
6607 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
6609 This code also handles discovering that
6611 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
6613 is a multiple of 8 so we don't have to worry about dealing with a
6616 Note that we *look* inside a SAVE_EXPR only to determine how it was
6617 calculated; it is not safe for fold to do much of anything else with the
6618 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
6619 at run time. For example, the latter example above *cannot* be implemented
6620 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
6621 evaluation time of the original SAVE_EXPR is not necessarily the same at
6622 the time the new expression is evaluated. The only optimization of this
6623 sort that would be valid is changing
6625 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
6629 SAVE_EXPR (I) * SAVE_EXPR (J)
6631 (where the same SAVE_EXPR (J) is used in the original and the
6632 transformed version). */
6635 multiple_of_p (type, top, bottom)
6640 if (operand_equal_p (top, bottom, 0))
6643 if (TREE_CODE (type) != INTEGER_TYPE)
6646 switch (TREE_CODE (top))
6649 return (multiple_of_p (type, TREE_OPERAND (top, 0), bottom)
6650 || multiple_of_p (type, TREE_OPERAND (top, 1), bottom));
6654 return (multiple_of_p (type, TREE_OPERAND (top, 0), bottom)
6655 && multiple_of_p (type, TREE_OPERAND (top, 1), bottom));
6658 /* Can't handle conversions from non-integral or wider integral type. */
6659 if ((TREE_CODE (TREE_TYPE (TREE_OPERAND (top, 0))) != INTEGER_TYPE)
6660 || (TYPE_PRECISION (type)
6661 < TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (top, 0)))))
6664 /* .. fall through ... */
6667 return multiple_of_p (type, TREE_OPERAND (top, 0), bottom);
6670 if ((TREE_CODE (bottom) != INTEGER_CST)
6671 || (tree_int_cst_sgn (top) < 0)
6672 || (tree_int_cst_sgn (bottom) < 0))
6674 return integer_zerop (const_binop (TRUNC_MOD_EXPR,