1 /* Copy propagation on hard registers for the GNU compiler.
2 Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009,
3 2010 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
12 GCC is distributed in the hope that it will be useful, but WITHOUT
13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
15 License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
23 #include "coretypes.h"
27 #include "insn-config.h"
29 #include "addresses.h"
30 #include "hard-reg-set.h"
31 #include "basic-block.h"
36 #include "diagnostic-core.h"
39 #include "tree-pass.h"
42 /* The following code does forward propagation of hard register copies.
43 The object is to eliminate as many dependencies as possible, so that
44 we have the most scheduling freedom. As a side effect, we also clean
45 up some silly register allocation decisions made by reload. This
46 code may be obsoleted by a new register allocator. */
48 /* DEBUG_INSNs aren't changed right away, as doing so might extend the
49 lifetime of a register and get the DEBUG_INSN subsequently reset.
50 So they are queued instead, and updated only when the register is
51 used in some subsequent real insn before it is set. */
52 struct queued_debug_insn_change
54 struct queued_debug_insn_change *next;
60 /* For each register, we have a list of registers that contain the same
61 value. The OLDEST_REGNO field points to the head of the list, and
62 the NEXT_REGNO field runs through the list. The MODE field indicates
63 what mode the data is known to be in; this field is VOIDmode when the
64 register is not known to contain valid data. */
66 struct value_data_entry
68 enum machine_mode mode;
69 unsigned int oldest_regno;
70 unsigned int next_regno;
71 struct queued_debug_insn_change *debug_insn_changes;
76 struct value_data_entry e[FIRST_PSEUDO_REGISTER];
77 unsigned int max_value_regs;
78 unsigned int n_debug_insn_changes;
81 static alloc_pool debug_insn_changes_pool;
83 static void kill_value_one_regno (unsigned, struct value_data *);
84 static void kill_value_regno (unsigned, unsigned, struct value_data *);
85 static void kill_value (rtx, struct value_data *);
86 static void set_value_regno (unsigned, enum machine_mode, struct value_data *);
87 static void init_value_data (struct value_data *);
88 static void kill_clobbered_value (rtx, const_rtx, void *);
89 static void kill_set_value (rtx, const_rtx, void *);
90 static int kill_autoinc_value (rtx *, void *);
91 static void copy_value (rtx, rtx, struct value_data *);
92 static bool mode_change_ok (enum machine_mode, enum machine_mode,
94 static rtx maybe_mode_change (enum machine_mode, enum machine_mode,
95 enum machine_mode, unsigned int, unsigned int);
96 static rtx find_oldest_value_reg (enum reg_class, rtx, struct value_data *);
97 static bool replace_oldest_value_reg (rtx *, enum reg_class, rtx,
99 static bool replace_oldest_value_addr (rtx *, enum reg_class,
100 enum machine_mode, addr_space_t, rtx,
101 struct value_data *);
102 static bool replace_oldest_value_mem (rtx, rtx, struct value_data *);
103 static bool copyprop_hardreg_forward_1 (basic_block, struct value_data *);
104 extern void debug_value_data (struct value_data *);
105 #ifdef ENABLE_CHECKING
106 static void validate_value_data (struct value_data *);
109 /* Free all queued updates for DEBUG_INSNs that change some reg to
113 free_debug_insn_changes (struct value_data *vd, unsigned int regno)
115 struct queued_debug_insn_change *cur, *next;
116 for (cur = vd->e[regno].debug_insn_changes; cur; cur = next)
119 --vd->n_debug_insn_changes;
120 pool_free (debug_insn_changes_pool, cur);
122 vd->e[regno].debug_insn_changes = NULL;
125 /* Kill register REGNO. This involves removing it from any value
126 lists, and resetting the value mode to VOIDmode. This is only a
127 helper function; it does not handle any hard registers overlapping
131 kill_value_one_regno (unsigned int regno, struct value_data *vd)
133 unsigned int i, next;
135 if (vd->e[regno].oldest_regno != regno)
137 for (i = vd->e[regno].oldest_regno;
138 vd->e[i].next_regno != regno;
139 i = vd->e[i].next_regno)
141 vd->e[i].next_regno = vd->e[regno].next_regno;
143 else if ((next = vd->e[regno].next_regno) != INVALID_REGNUM)
145 for (i = next; i != INVALID_REGNUM; i = vd->e[i].next_regno)
146 vd->e[i].oldest_regno = next;
149 vd->e[regno].mode = VOIDmode;
150 vd->e[regno].oldest_regno = regno;
151 vd->e[regno].next_regno = INVALID_REGNUM;
152 if (vd->e[regno].debug_insn_changes)
153 free_debug_insn_changes (vd, regno);
155 #ifdef ENABLE_CHECKING
156 validate_value_data (vd);
160 /* Kill the value in register REGNO for NREGS, and any other registers
161 whose values overlap. */
164 kill_value_regno (unsigned int regno, unsigned int nregs,
165 struct value_data *vd)
169 /* Kill the value we're told to kill. */
170 for (j = 0; j < nregs; ++j)
171 kill_value_one_regno (regno + j, vd);
173 /* Kill everything that overlapped what we're told to kill. */
174 if (regno < vd->max_value_regs)
177 j = regno - vd->max_value_regs;
178 for (; j < regno; ++j)
181 if (vd->e[j].mode == VOIDmode)
183 n = hard_regno_nregs[j][vd->e[j].mode];
185 for (i = 0; i < n; ++i)
186 kill_value_one_regno (j + i, vd);
190 /* Kill X. This is a convenience function wrapping kill_value_regno
191 so that we mind the mode the register is in. */
194 kill_value (rtx x, struct value_data *vd)
198 if (GET_CODE (x) == SUBREG)
200 x = simplify_subreg (GET_MODE (x), SUBREG_REG (x),
201 GET_MODE (SUBREG_REG (x)), SUBREG_BYTE (x));
203 x = SUBREG_REG (orig_rtx);
207 unsigned int regno = REGNO (x);
208 unsigned int n = hard_regno_nregs[regno][GET_MODE (x)];
210 kill_value_regno (regno, n, vd);
214 /* Remember that REGNO is valid in MODE. */
217 set_value_regno (unsigned int regno, enum machine_mode mode,
218 struct value_data *vd)
222 vd->e[regno].mode = mode;
224 nregs = hard_regno_nregs[regno][mode];
225 if (nregs > vd->max_value_regs)
226 vd->max_value_regs = nregs;
229 /* Initialize VD such that there are no known relationships between regs. */
232 init_value_data (struct value_data *vd)
235 for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
237 vd->e[i].mode = VOIDmode;
238 vd->e[i].oldest_regno = i;
239 vd->e[i].next_regno = INVALID_REGNUM;
240 vd->e[i].debug_insn_changes = NULL;
242 vd->max_value_regs = 0;
243 vd->n_debug_insn_changes = 0;
246 /* Called through note_stores. If X is clobbered, kill its value. */
249 kill_clobbered_value (rtx x, const_rtx set, void *data)
251 struct value_data *const vd = (struct value_data *) data;
252 if (GET_CODE (set) == CLOBBER)
256 /* A structure passed as data to kill_set_value through note_stores. */
257 struct kill_set_value_data
259 struct value_data *vd;
263 /* Called through note_stores. If X is set, not clobbered, kill its
264 current value and install it as the root of its own value list. */
267 kill_set_value (rtx x, const_rtx set, void *data)
269 struct kill_set_value_data *ksvd = (struct kill_set_value_data *) data;
270 if (rtx_equal_p (x, ksvd->ignore_set_reg))
272 if (GET_CODE (set) != CLOBBER)
274 kill_value (x, ksvd->vd);
276 set_value_regno (REGNO (x), GET_MODE (x), ksvd->vd);
280 /* Called through for_each_rtx. Kill any register used as the base of an
281 auto-increment expression, and install that register as the root of its
285 kill_autoinc_value (rtx *px, void *data)
288 struct value_data *const vd = (struct value_data *) data;
290 if (GET_RTX_CLASS (GET_CODE (x)) == RTX_AUTOINC)
294 set_value_regno (REGNO (x), GET_MODE (x), vd);
301 /* Assert that SRC has been copied to DEST. Adjust the data structures
302 to reflect that SRC contains an older copy of the shared value. */
305 copy_value (rtx dest, rtx src, struct value_data *vd)
307 unsigned int dr = REGNO (dest);
308 unsigned int sr = REGNO (src);
312 /* ??? At present, it's possible to see noop sets. It'd be nice if
313 this were cleaned up beforehand... */
317 /* Do not propagate copies to the stack pointer, as that can leave
318 memory accesses with no scheduling dependency on the stack update. */
319 if (dr == STACK_POINTER_REGNUM)
322 /* Likewise with the frame pointer, if we're using one. */
323 if (frame_pointer_needed && dr == HARD_FRAME_POINTER_REGNUM)
326 /* Do not propagate copies to fixed or global registers, patterns
327 can be relying to see particular fixed register or users can
328 expect the chosen global register in asm. */
329 if (fixed_regs[dr] || global_regs[dr])
332 /* If SRC and DEST overlap, don't record anything. */
333 dn = hard_regno_nregs[dr][GET_MODE (dest)];
334 sn = hard_regno_nregs[sr][GET_MODE (dest)];
335 if ((dr > sr && dr < sr + sn)
336 || (sr > dr && sr < dr + dn))
339 /* If SRC had no assigned mode (i.e. we didn't know it was live)
340 assign it now and assume the value came from an input argument
342 if (vd->e[sr].mode == VOIDmode)
343 set_value_regno (sr, vd->e[dr].mode, vd);
345 /* If we are narrowing the input to a smaller number of hard regs,
346 and it is in big endian, we are really extracting a high part.
347 Since we generally associate a low part of a value with the value itself,
348 we must not do the same for the high part.
349 Note we can still get low parts for the same mode combination through
350 a two-step copy involving differently sized hard regs.
351 Assume hard regs fr* are 32 bits bits each, while r* are 64 bits each:
352 (set (reg:DI r0) (reg:DI fr0))
353 (set (reg:SI fr2) (reg:SI r0))
354 loads the low part of (reg:DI fr0) - i.e. fr1 - into fr2, while:
355 (set (reg:SI fr2) (reg:SI fr0))
356 loads the high part of (reg:DI fr0) into fr2.
358 We can't properly represent the latter case in our tables, so don't
359 record anything then. */
360 else if (sn < (unsigned int) hard_regno_nregs[sr][vd->e[sr].mode]
361 && (GET_MODE_SIZE (vd->e[sr].mode) > UNITS_PER_WORD
362 ? WORDS_BIG_ENDIAN : BYTES_BIG_ENDIAN))
365 /* If SRC had been assigned a mode narrower than the copy, we can't
366 link DEST into the chain, because not all of the pieces of the
367 copy came from oldest_regno. */
368 else if (sn > (unsigned int) hard_regno_nregs[sr][vd->e[sr].mode])
371 /* Link DR at the end of the value chain used by SR. */
373 vd->e[dr].oldest_regno = vd->e[sr].oldest_regno;
375 for (i = sr; vd->e[i].next_regno != INVALID_REGNUM; i = vd->e[i].next_regno)
377 vd->e[i].next_regno = dr;
379 #ifdef ENABLE_CHECKING
380 validate_value_data (vd);
384 /* Return true if a mode change from ORIG to NEW is allowed for REGNO. */
387 mode_change_ok (enum machine_mode orig_mode, enum machine_mode new_mode,
388 unsigned int regno ATTRIBUTE_UNUSED)
390 if (GET_MODE_SIZE (orig_mode) < GET_MODE_SIZE (new_mode))
393 #ifdef CANNOT_CHANGE_MODE_CLASS
394 return !REG_CANNOT_CHANGE_MODE_P (regno, orig_mode, new_mode);
400 /* Register REGNO was originally set in ORIG_MODE. It - or a copy of it -
401 was copied in COPY_MODE to COPY_REGNO, and then COPY_REGNO was accessed
403 Return a NEW_MODE rtx for REGNO if that's OK, otherwise return NULL_RTX. */
406 maybe_mode_change (enum machine_mode orig_mode, enum machine_mode copy_mode,
407 enum machine_mode new_mode, unsigned int regno,
408 unsigned int copy_regno ATTRIBUTE_UNUSED)
410 if (GET_MODE_SIZE (copy_mode) < GET_MODE_SIZE (orig_mode)
411 && GET_MODE_SIZE (copy_mode) < GET_MODE_SIZE (new_mode))
414 if (orig_mode == new_mode)
415 return gen_rtx_raw_REG (new_mode, regno);
416 else if (mode_change_ok (orig_mode, new_mode, regno))
418 int copy_nregs = hard_regno_nregs[copy_regno][copy_mode];
419 int use_nregs = hard_regno_nregs[copy_regno][new_mode];
421 = GET_MODE_SIZE (copy_mode) / copy_nregs * (copy_nregs - use_nregs);
423 = GET_MODE_SIZE (orig_mode) - GET_MODE_SIZE (new_mode) - copy_offset;
424 int byteoffset = offset % UNITS_PER_WORD;
425 int wordoffset = offset - byteoffset;
427 offset = ((WORDS_BIG_ENDIAN ? wordoffset : 0)
428 + (BYTES_BIG_ENDIAN ? byteoffset : 0));
429 regno += subreg_regno_offset (regno, orig_mode, offset, new_mode);
430 if (HARD_REGNO_MODE_OK (regno, new_mode))
431 return gen_rtx_raw_REG (new_mode, regno);
436 /* Find the oldest copy of the value contained in REGNO that is in
437 register class CL and has mode MODE. If found, return an rtx
438 of that oldest register, otherwise return NULL. */
441 find_oldest_value_reg (enum reg_class cl, rtx reg, struct value_data *vd)
443 unsigned int regno = REGNO (reg);
444 enum machine_mode mode = GET_MODE (reg);
447 /* If we are accessing REG in some mode other that what we set it in,
448 make sure that the replacement is valid. In particular, consider
449 (set (reg:DI r11) (...))
450 (set (reg:SI r9) (reg:SI r11))
451 (set (reg:SI r10) (...))
452 (set (...) (reg:DI r9))
453 Replacing r9 with r11 is invalid. */
454 if (mode != vd->e[regno].mode)
456 if (hard_regno_nregs[regno][mode]
457 > hard_regno_nregs[regno][vd->e[regno].mode])
461 for (i = vd->e[regno].oldest_regno; i != regno; i = vd->e[i].next_regno)
463 enum machine_mode oldmode = vd->e[i].mode;
466 if (!in_hard_reg_set_p (reg_class_contents[cl], mode, i))
469 new_rtx = maybe_mode_change (oldmode, vd->e[regno].mode, mode, i, regno);
472 ORIGINAL_REGNO (new_rtx) = ORIGINAL_REGNO (reg);
473 REG_ATTRS (new_rtx) = REG_ATTRS (reg);
474 REG_POINTER (new_rtx) = REG_POINTER (reg);
482 /* If possible, replace the register at *LOC with the oldest register
483 in register class CL. Return true if successfully replaced. */
486 replace_oldest_value_reg (rtx *loc, enum reg_class cl, rtx insn,
487 struct value_data *vd)
489 rtx new_rtx = find_oldest_value_reg (cl, *loc, vd);
492 if (DEBUG_INSN_P (insn))
494 struct queued_debug_insn_change *change;
497 fprintf (dump_file, "debug_insn %u: queued replacing reg %u with %u\n",
498 INSN_UID (insn), REGNO (*loc), REGNO (new_rtx));
500 change = (struct queued_debug_insn_change *)
501 pool_alloc (debug_insn_changes_pool);
502 change->next = vd->e[REGNO (new_rtx)].debug_insn_changes;
505 change->new_rtx = new_rtx;
506 vd->e[REGNO (new_rtx)].debug_insn_changes = change;
507 ++vd->n_debug_insn_changes;
511 fprintf (dump_file, "insn %u: replaced reg %u with %u\n",
512 INSN_UID (insn), REGNO (*loc), REGNO (new_rtx));
514 validate_change (insn, loc, new_rtx, 1);
520 /* Similar to replace_oldest_value_reg, but *LOC contains an address.
521 Adapted from find_reloads_address_1. CL is INDEX_REG_CLASS or
522 BASE_REG_CLASS depending on how the register is being considered. */
525 replace_oldest_value_addr (rtx *loc, enum reg_class cl,
526 enum machine_mode mode, addr_space_t as,
527 rtx insn, struct value_data *vd)
530 RTX_CODE code = GET_CODE (x);
533 bool changed = false;
538 if (DEBUG_INSN_P (insn))
542 rtx orig_op0 = XEXP (x, 0);
543 rtx orig_op1 = XEXP (x, 1);
544 RTX_CODE code0 = GET_CODE (orig_op0);
545 RTX_CODE code1 = GET_CODE (orig_op1);
550 enum rtx_code index_code = SCRATCH;
552 if (GET_CODE (op0) == SUBREG)
554 op0 = SUBREG_REG (op0);
555 code0 = GET_CODE (op0);
558 if (GET_CODE (op1) == SUBREG)
560 op1 = SUBREG_REG (op1);
561 code1 = GET_CODE (op1);
564 if (code0 == MULT || code0 == SIGN_EXTEND || code0 == TRUNCATE
565 || code0 == ZERO_EXTEND || code1 == MEM)
569 index_code = GET_CODE (*locI);
571 else if (code1 == MULT || code1 == SIGN_EXTEND || code1 == TRUNCATE
572 || code1 == ZERO_EXTEND || code0 == MEM)
576 index_code = GET_CODE (*locI);
578 else if (code0 == CONST_INT || code0 == CONST
579 || code0 == SYMBOL_REF || code0 == LABEL_REF)
582 index_code = GET_CODE (XEXP (x, 0));
584 else if (code1 == CONST_INT || code1 == CONST
585 || code1 == SYMBOL_REF || code1 == LABEL_REF)
588 index_code = GET_CODE (XEXP (x, 1));
590 else if (code0 == REG && code1 == REG)
593 unsigned regno0 = REGNO (op0), regno1 = REGNO (op1);
595 if (REGNO_OK_FOR_INDEX_P (regno1)
596 && regno_ok_for_base_p (regno0, mode, as, PLUS, REG))
598 else if (REGNO_OK_FOR_INDEX_P (regno0)
599 && regno_ok_for_base_p (regno1, mode, as, PLUS, REG))
601 else if (regno_ok_for_base_p (regno0, mode, as, PLUS, REG)
602 || REGNO_OK_FOR_INDEX_P (regno1))
604 else if (regno_ok_for_base_p (regno1, mode, as, PLUS, REG))
609 locI = &XEXP (x, index_op);
610 locB = &XEXP (x, !index_op);
611 index_code = GET_CODE (*locI);
613 else if (code0 == REG)
617 index_code = GET_CODE (*locI);
619 else if (code1 == REG)
623 index_code = GET_CODE (*locI);
627 changed |= replace_oldest_value_addr (locI, INDEX_REG_CLASS,
630 changed |= replace_oldest_value_addr (locB,
631 base_reg_class (mode, as, PLUS,
646 return replace_oldest_value_mem (x, insn, vd);
649 return replace_oldest_value_reg (loc, cl, insn, vd);
655 fmt = GET_RTX_FORMAT (code);
656 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
659 changed |= replace_oldest_value_addr (&XEXP (x, i), cl, mode, as,
661 else if (fmt[i] == 'E')
662 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
663 changed |= replace_oldest_value_addr (&XVECEXP (x, i, j), cl,
670 /* Similar to replace_oldest_value_reg, but X contains a memory. */
673 replace_oldest_value_mem (rtx x, rtx insn, struct value_data *vd)
677 if (DEBUG_INSN_P (insn))
680 cl = base_reg_class (GET_MODE (x), MEM_ADDR_SPACE (x), MEM, SCRATCH);
682 return replace_oldest_value_addr (&XEXP (x, 0), cl,
683 GET_MODE (x), MEM_ADDR_SPACE (x),
687 /* Apply all queued updates for DEBUG_INSNs that change some reg to
691 apply_debug_insn_changes (struct value_data *vd, unsigned int regno)
693 struct queued_debug_insn_change *change;
694 rtx last_insn = vd->e[regno].debug_insn_changes->insn;
696 for (change = vd->e[regno].debug_insn_changes;
698 change = change->next)
700 if (last_insn != change->insn)
702 apply_change_group ();
703 last_insn = change->insn;
705 validate_change (change->insn, change->loc, change->new_rtx, 1);
707 apply_change_group ();
710 /* Called via for_each_rtx, for all used registers in a real
711 insn apply DEBUG_INSN changes that change registers to the
715 cprop_find_used_regs_1 (rtx *loc, void *data)
719 struct value_data *vd = (struct value_data *) data;
720 if (vd->e[REGNO (*loc)].debug_insn_changes)
722 apply_debug_insn_changes (vd, REGNO (*loc));
723 free_debug_insn_changes (vd, REGNO (*loc));
729 /* Called via note_uses, for all used registers in a real insn
730 apply DEBUG_INSN changes that change registers to the used
734 cprop_find_used_regs (rtx *loc, void *vd)
736 for_each_rtx (loc, cprop_find_used_regs_1, vd);
739 /* Perform the forward copy propagation on basic block BB. */
742 copyprop_hardreg_forward_1 (basic_block bb, struct value_data *vd)
744 bool anything_changed = false;
747 for (insn = BB_HEAD (bb); ; insn = NEXT_INSN (insn))
749 int n_ops, i, alt, predicated;
750 bool is_asm, any_replacements;
752 bool replaced[MAX_RECOG_OPERANDS];
753 bool changed = false;
754 struct kill_set_value_data ksvd;
756 if (!NONDEBUG_INSN_P (insn))
758 if (DEBUG_INSN_P (insn))
760 rtx loc = INSN_VAR_LOCATION_LOC (insn);
761 if (!VAR_LOC_UNKNOWN_P (loc))
762 replace_oldest_value_addr (&INSN_VAR_LOCATION_LOC (insn),
763 ALL_REGS, GET_MODE (loc),
764 ADDR_SPACE_GENERIC, insn, vd);
767 if (insn == BB_END (bb))
773 set = single_set (insn);
775 if (! constrain_operands (1))
776 fatal_insn_not_found (insn);
777 preprocess_constraints ();
778 alt = which_alternative;
779 n_ops = recog_data.n_operands;
780 is_asm = asm_noperands (PATTERN (insn)) >= 0;
782 /* Simplify the code below by rewriting things to reflect
783 matching constraints. Also promote OP_OUT to OP_INOUT
784 in predicated instructions. */
786 predicated = GET_CODE (PATTERN (insn)) == COND_EXEC;
787 for (i = 0; i < n_ops; ++i)
789 int matches = recog_op_alt[i][alt].matches;
791 recog_op_alt[i][alt].cl = recog_op_alt[matches][alt].cl;
792 if (matches >= 0 || recog_op_alt[i][alt].matched >= 0
793 || (predicated && recog_data.operand_type[i] == OP_OUT))
794 recog_data.operand_type[i] = OP_INOUT;
797 /* Apply changes to earlier DEBUG_INSNs if possible. */
798 if (vd->n_debug_insn_changes)
799 note_uses (&PATTERN (insn), cprop_find_used_regs, vd);
801 /* For each earlyclobber operand, zap the value data. */
802 for (i = 0; i < n_ops; i++)
803 if (recog_op_alt[i][alt].earlyclobber)
804 kill_value (recog_data.operand[i], vd);
806 /* Within asms, a clobber cannot overlap inputs or outputs.
807 I wouldn't think this were true for regular insns, but
808 scan_rtx treats them like that... */
809 note_stores (PATTERN (insn), kill_clobbered_value, vd);
811 /* Kill all auto-incremented values. */
812 /* ??? REG_INC is useless, since stack pushes aren't done that way. */
813 for_each_rtx (&PATTERN (insn), kill_autoinc_value, vd);
815 /* Kill all early-clobbered operands. */
816 for (i = 0; i < n_ops; i++)
817 if (recog_op_alt[i][alt].earlyclobber)
818 kill_value (recog_data.operand[i], vd);
820 /* Special-case plain move instructions, since we may well
821 be able to do the move from a different register class. */
822 if (set && REG_P (SET_SRC (set)))
824 rtx src = SET_SRC (set);
825 unsigned int regno = REGNO (src);
826 enum machine_mode mode = GET_MODE (src);
830 /* If we are accessing SRC in some mode other that what we
831 set it in, make sure that the replacement is valid. */
832 if (mode != vd->e[regno].mode)
834 if (hard_regno_nregs[regno][mode]
835 > hard_regno_nregs[regno][vd->e[regno].mode])
836 goto no_move_special_case;
838 /* And likewise, if we are narrowing on big endian the transformation
840 if (hard_regno_nregs[regno][mode]
841 < hard_regno_nregs[regno][vd->e[regno].mode]
842 && (GET_MODE_SIZE (vd->e[regno].mode) > UNITS_PER_WORD
843 ? WORDS_BIG_ENDIAN : BYTES_BIG_ENDIAN))
844 goto no_move_special_case;
847 /* If the destination is also a register, try to find a source
848 register in the same class. */
849 if (REG_P (SET_DEST (set)))
851 new_rtx = find_oldest_value_reg (REGNO_REG_CLASS (regno), src, vd);
852 if (new_rtx && validate_change (insn, &SET_SRC (set), new_rtx, 0))
856 "insn %u: replaced reg %u with %u\n",
857 INSN_UID (insn), regno, REGNO (new_rtx));
859 goto did_replacement;
861 /* We need to re-extract as validate_change clobbers
864 if (! constrain_operands (1))
865 fatal_insn_not_found (insn);
866 preprocess_constraints ();
869 /* Otherwise, try all valid registers and see if its valid. */
870 for (i = vd->e[regno].oldest_regno; i != regno;
871 i = vd->e[i].next_regno)
873 new_rtx = maybe_mode_change (vd->e[i].mode, vd->e[regno].mode,
875 if (new_rtx != NULL_RTX)
877 if (validate_change (insn, &SET_SRC (set), new_rtx, 0))
879 ORIGINAL_REGNO (new_rtx) = ORIGINAL_REGNO (src);
880 REG_ATTRS (new_rtx) = REG_ATTRS (src);
881 REG_POINTER (new_rtx) = REG_POINTER (src);
884 "insn %u: replaced reg %u with %u\n",
885 INSN_UID (insn), regno, REGNO (new_rtx));
887 goto did_replacement;
889 /* We need to re-extract as validate_change clobbers
892 if (! constrain_operands (1))
893 fatal_insn_not_found (insn);
894 preprocess_constraints ();
898 no_move_special_case:
900 any_replacements = false;
902 /* For each input operand, replace a hard register with the
903 eldest live copy that's in an appropriate register class. */
904 for (i = 0; i < n_ops; i++)
908 /* Don't scan match_operand here, since we've no reg class
909 information to pass down. Any operands that we could
910 substitute in will be represented elsewhere. */
911 if (recog_data.constraints[i][0] == '\0')
914 /* Don't replace in asms intentionally referencing hard regs. */
915 if (is_asm && REG_P (recog_data.operand[i])
916 && (REGNO (recog_data.operand[i])
917 == ORIGINAL_REGNO (recog_data.operand[i])))
920 if (recog_data.operand_type[i] == OP_IN)
922 if (recog_op_alt[i][alt].is_address)
924 = replace_oldest_value_addr (recog_data.operand_loc[i],
925 recog_op_alt[i][alt].cl,
926 VOIDmode, ADDR_SPACE_GENERIC,
928 else if (REG_P (recog_data.operand[i]))
930 = replace_oldest_value_reg (recog_data.operand_loc[i],
931 recog_op_alt[i][alt].cl,
933 else if (MEM_P (recog_data.operand[i]))
934 replaced[i] = replace_oldest_value_mem (recog_data.operand[i],
937 else if (MEM_P (recog_data.operand[i]))
938 replaced[i] = replace_oldest_value_mem (recog_data.operand[i],
941 /* If we performed any replacement, update match_dups. */
947 new_rtx = *recog_data.operand_loc[i];
948 recog_data.operand[i] = new_rtx;
949 for (j = 0; j < recog_data.n_dups; j++)
950 if (recog_data.dup_num[j] == i)
951 validate_unshare_change (insn, recog_data.dup_loc[j], new_rtx, 1);
953 any_replacements = true;
957 if (any_replacements)
959 if (! apply_change_group ())
961 for (i = 0; i < n_ops; i++)
964 rtx old = *recog_data.operand_loc[i];
965 recog_data.operand[i] = old;
970 "insn %u: reg replacements not verified\n",
980 anything_changed = true;
982 /* If something changed, perhaps further changes to earlier
983 DEBUG_INSNs can be applied. */
984 if (vd->n_debug_insn_changes)
985 note_uses (&PATTERN (insn), cprop_find_used_regs, vd);
989 ksvd.ignore_set_reg = NULL_RTX;
991 /* Clobber call-clobbered registers. */
994 int set_regno = INVALID_REGNUM;
997 for (exp = CALL_INSN_FUNCTION_USAGE (insn); exp; exp = XEXP (exp, 1))
999 rtx x = XEXP (exp, 0);
1000 if (GET_CODE (x) == SET)
1002 rtx dest = SET_DEST (x);
1003 kill_value (dest, vd);
1004 set_value_regno (REGNO (dest), GET_MODE (dest), vd);
1005 copy_value (dest, SET_SRC (x), vd);
1006 ksvd.ignore_set_reg = dest;
1007 set_regno = REGNO (dest);
1009 = hard_regno_nregs[set_regno][GET_MODE (dest)];
1013 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1014 if (TEST_HARD_REG_BIT (regs_invalidated_by_call, i)
1015 && (i < set_regno || i >= set_regno + set_nregs))
1016 kill_value_regno (i, 1, vd);
1019 /* Notice stores. */
1020 note_stores (PATTERN (insn), kill_set_value, &ksvd);
1022 /* Notice copies. */
1023 if (set && REG_P (SET_DEST (set)) && REG_P (SET_SRC (set)))
1024 copy_value (SET_DEST (set), SET_SRC (set), vd);
1026 if (insn == BB_END (bb))
1030 return anything_changed;
1033 /* Main entry point for the forward copy propagation optimization. */
1036 copyprop_hardreg_forward (void)
1038 struct value_data *all_vd;
1041 bool analyze_called = false;
1043 all_vd = XNEWVEC (struct value_data, last_basic_block);
1045 visited = sbitmap_alloc (last_basic_block);
1046 sbitmap_zero (visited);
1048 if (MAY_HAVE_DEBUG_INSNS)
1049 debug_insn_changes_pool
1050 = create_alloc_pool ("debug insn changes pool",
1051 sizeof (struct queued_debug_insn_change), 256);
1055 SET_BIT (visited, bb->index);
1057 /* If a block has a single predecessor, that we've already
1058 processed, begin with the value data that was live at
1059 the end of the predecessor block. */
1060 /* ??? Ought to use more intelligent queuing of blocks. */
1061 if (single_pred_p (bb)
1062 && TEST_BIT (visited, single_pred (bb)->index)
1063 && ! (single_pred_edge (bb)->flags & (EDGE_ABNORMAL_CALL | EDGE_EH)))
1065 all_vd[bb->index] = all_vd[single_pred (bb)->index];
1066 if (all_vd[bb->index].n_debug_insn_changes)
1070 for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
1072 if (all_vd[bb->index].e[regno].debug_insn_changes)
1074 all_vd[bb->index].e[regno].debug_insn_changes = NULL;
1075 if (--all_vd[bb->index].n_debug_insn_changes == 0)
1082 init_value_data (all_vd + bb->index);
1084 copyprop_hardreg_forward_1 (bb, all_vd + bb->index);
1087 if (MAY_HAVE_DEBUG_INSNS)
1090 if (TEST_BIT (visited, bb->index)
1091 && all_vd[bb->index].n_debug_insn_changes)
1096 if (!analyze_called)
1099 analyze_called = true;
1101 live = df_get_live_out (bb);
1102 for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
1103 if (all_vd[bb->index].e[regno].debug_insn_changes)
1105 if (REGNO_REG_SET_P (live, regno))
1106 apply_debug_insn_changes (all_vd + bb->index, regno);
1107 if (all_vd[bb->index].n_debug_insn_changes == 0)
1112 free_alloc_pool (debug_insn_changes_pool);
1115 sbitmap_free (visited);
1120 /* Dump the value chain data to stderr. */
1123 debug_value_data (struct value_data *vd)
1128 CLEAR_HARD_REG_SET (set);
1130 for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
1131 if (vd->e[i].oldest_regno == i)
1133 if (vd->e[i].mode == VOIDmode)
1135 if (vd->e[i].next_regno != INVALID_REGNUM)
1136 fprintf (stderr, "[%u] Bad next_regno for empty chain (%u)\n",
1137 i, vd->e[i].next_regno);
1141 SET_HARD_REG_BIT (set, i);
1142 fprintf (stderr, "[%u %s] ", i, GET_MODE_NAME (vd->e[i].mode));
1144 for (j = vd->e[i].next_regno;
1145 j != INVALID_REGNUM;
1146 j = vd->e[j].next_regno)
1148 if (TEST_HARD_REG_BIT (set, j))
1150 fprintf (stderr, "[%u] Loop in regno chain\n", j);
1154 if (vd->e[j].oldest_regno != i)
1156 fprintf (stderr, "[%u] Bad oldest_regno (%u)\n",
1157 j, vd->e[j].oldest_regno);
1160 SET_HARD_REG_BIT (set, j);
1161 fprintf (stderr, "[%u %s] ", j, GET_MODE_NAME (vd->e[j].mode));
1163 fputc ('\n', stderr);
1166 for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
1167 if (! TEST_HARD_REG_BIT (set, i)
1168 && (vd->e[i].mode != VOIDmode
1169 || vd->e[i].oldest_regno != i
1170 || vd->e[i].next_regno != INVALID_REGNUM))
1171 fprintf (stderr, "[%u] Non-empty reg in chain (%s %u %i)\n",
1172 i, GET_MODE_NAME (vd->e[i].mode), vd->e[i].oldest_regno,
1173 vd->e[i].next_regno);
1176 #ifdef ENABLE_CHECKING
1178 validate_value_data (struct value_data *vd)
1183 CLEAR_HARD_REG_SET (set);
1185 for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
1186 if (vd->e[i].oldest_regno == i)
1188 if (vd->e[i].mode == VOIDmode)
1190 if (vd->e[i].next_regno != INVALID_REGNUM)
1191 internal_error ("validate_value_data: [%u] Bad next_regno for empty chain (%u)",
1192 i, vd->e[i].next_regno);
1196 SET_HARD_REG_BIT (set, i);
1198 for (j = vd->e[i].next_regno;
1199 j != INVALID_REGNUM;
1200 j = vd->e[j].next_regno)
1202 if (TEST_HARD_REG_BIT (set, j))
1203 internal_error ("validate_value_data: Loop in regno chain (%u)",
1205 if (vd->e[j].oldest_regno != i)
1206 internal_error ("validate_value_data: [%u] Bad oldest_regno (%u)",
1207 j, vd->e[j].oldest_regno);
1209 SET_HARD_REG_BIT (set, j);
1213 for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
1214 if (! TEST_HARD_REG_BIT (set, i)
1215 && (vd->e[i].mode != VOIDmode
1216 || vd->e[i].oldest_regno != i
1217 || vd->e[i].next_regno != INVALID_REGNUM))
1218 internal_error ("validate_value_data: [%u] Non-empty reg in chain (%s %u %i)",
1219 i, GET_MODE_NAME (vd->e[i].mode), vd->e[i].oldest_regno,
1220 vd->e[i].next_regno);
1225 gate_handle_cprop (void)
1227 return (optimize > 0 && (flag_cprop_registers));
1231 struct rtl_opt_pass pass_cprop_hardreg =
1235 "cprop_hardreg", /* name */
1236 gate_handle_cprop, /* gate */
1237 copyprop_hardreg_forward, /* execute */
1240 0, /* static_pass_number */
1241 TV_CPROP_REGISTERS, /* tv_id */
1242 0, /* properties_required */
1243 0, /* properties_provided */
1244 0, /* properties_destroyed */
1245 0, /* todo_flags_start */
1247 | TODO_verify_rtl_sharing /* todo_flags_finish */