1 /* Expands front end tree to back end RTL for GCC
2 Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997,
3 1998, 1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
22 /* This file handles the generation of rtl code from tree structure
23 above the level of expressions, using subroutines in exp*.c and emit-rtl.c.
24 It also creates the rtl expressions for parameters and auto variables
25 and has full responsibility for allocating stack slots.
27 The functions whose names start with `expand_' are called by the
28 parser to generate RTL instructions for various kinds of constructs.
30 Some control and binding constructs require calling several such
31 functions at different times. For example, a simple if-then
32 is expanded by calling `expand_start_cond' (with the condition-expression
33 as argument) before parsing the then-clause and calling `expand_end_cond'
34 after parsing the then-clause. */
38 #include "coretypes.h"
47 #include "insn-config.h"
50 #include "hard-reg-set.h"
57 #include "langhooks.h"
62 /* Assume that case vectors are not pc-relative. */
63 #ifndef CASE_VECTOR_PC_RELATIVE
64 #define CASE_VECTOR_PC_RELATIVE 0
67 /* Functions and data structures for expanding case statements. */
69 /* Case label structure, used to hold info on labels within case
70 statements. We handle "range" labels; for a single-value label
71 as in C, the high and low limits are the same.
73 An AVL tree of case nodes is initially created, and later transformed
74 to a list linked via the RIGHT fields in the nodes. Nodes with
75 higher case values are later in the list.
77 Switch statements can be output in one of two forms. A branch table
78 is used if there are more than a few labels and the labels are dense
79 within the range between the smallest and largest case value. If a
80 branch table is used, no further manipulations are done with the case
83 The alternative to the use of a branch table is to generate a series
84 of compare and jump insns. When that is done, we use the LEFT, RIGHT,
85 and PARENT fields to hold a binary tree. Initially the tree is
86 totally unbalanced, with everything on the right. We balance the tree
87 with nodes on the left having lower case values than the parent
88 and nodes on the right having higher values. We then output the tree
91 struct case_node GTY(())
93 struct case_node *left; /* Left son in binary tree */
94 struct case_node *right; /* Right son in binary tree; also node chain */
95 struct case_node *parent; /* Parent of node in binary tree */
96 tree low; /* Lowest index value for this label */
97 tree high; /* Highest index value for this label */
98 tree code_label; /* Label to jump to when node matches */
102 typedef struct case_node case_node;
103 typedef struct case_node *case_node_ptr;
105 /* These are used by estimate_case_costs and balance_case_nodes. */
107 /* This must be a signed type, and non-ANSI compilers lack signed char. */
108 static short cost_table_[129];
109 static int use_cost_table;
110 static int cost_table_initialized;
112 /* Special care is needed because we allow -1, but TREE_INT_CST_LOW
114 #define COST_TABLE(I) cost_table_[(unsigned HOST_WIDE_INT) ((I) + 1)]
116 /* Stack of control and binding constructs we are currently inside.
118 These constructs begin when you call `expand_start_WHATEVER'
119 and end when you call `expand_end_WHATEVER'. This stack records
120 info about how the construct began that tells the end-function
121 what to do. It also may provide information about the construct
122 to alter the behavior of other constructs within the body.
123 For example, they may affect the behavior of C `break' and `continue'.
125 Each construct gets one `struct nesting' object.
126 All of these objects are chained through the `all' field.
127 `nesting_stack' points to the first object (innermost construct).
128 The position of an entry on `nesting_stack' is in its `depth' field.
130 Each type of construct has its own individual stack.
131 For example, loops have `loop_stack'. Each object points to the
132 next object of the same type through the `next' field.
134 Some constructs are visible to `break' exit-statements and others
135 are not. Which constructs are visible depends on the language.
136 Therefore, the data structure allows each construct to be visible
137 or not, according to the args given when the construct is started.
138 The construct is visible if the `exit_label' field is non-null.
139 In that case, the value should be a CODE_LABEL rtx. */
141 struct nesting GTY(())
144 struct nesting *next;
155 /* For conds (if-then and if-then-else statements). */
158 /* Label for the end of the if construct.
159 There is none if EXITFLAG was not set
160 and no `else' has been seen yet. */
162 /* Label for the end of this alternative.
163 This may be the end of the if or the next else/elseif. */
165 } GTY ((tag ("COND_NESTING"))) cond;
169 /* Label at the top of the loop; place to loop back to. */
171 /* Label at the end of the whole construct. */
173 /* Label for `continue' statement to jump to;
174 this is in front of the stepper of the loop. */
176 } GTY ((tag ("LOOP_NESTING"))) loop;
177 /* For variable binding contours. */
180 /* Sequence number of this binding contour within the function,
181 in order of entry. */
182 int block_start_count;
183 /* Nonzero => value to restore stack to on exit. */
185 /* The NOTE that starts this contour.
186 Used by expand_goto to check whether the destination
187 is within each contour or not. */
189 /* Innermost containing binding contour that has a stack level. */
190 struct nesting *innermost_stack_block;
191 /* List of cleanups to be run on exit from this contour.
192 This is a list of expressions to be evaluated.
193 The TREE_PURPOSE of each link is the ..._DECL node
194 which the cleanup pertains to. */
196 /* List of cleanup-lists of blocks containing this block,
197 as they were at the locus where this block appears.
198 There is an element for each containing block,
199 ordered innermost containing block first.
200 The tail of this list can be 0,
201 if all remaining elements would be empty lists.
202 The element's TREE_VALUE is the cleanup-list of that block,
203 which may be null. */
205 /* Chain of labels defined inside this binding contour.
206 For contours that have stack levels or cleanups. */
207 struct label_chain *label_chain;
208 /* Nonzero if this is associated with an EH region. */
209 int exception_region;
210 /* The saved target_temp_slot_level from our outer block.
211 We may reset target_temp_slot_level to be the level of
212 this block, if that is done, target_temp_slot_level
213 reverts to the saved target_temp_slot_level at the very
215 int block_target_temp_slot_level;
216 /* True if we are currently emitting insns in an area of
217 output code that is controlled by a conditional
218 expression. This is used by the cleanup handling code to
219 generate conditional cleanup actions. */
220 int conditional_code;
221 /* A place to move the start of the exception region for any
222 of the conditional cleanups, must be at the end or after
223 the start of the last unconditional cleanup, and before any
224 conditional branch points. */
225 rtx last_unconditional_cleanup;
226 } GTY ((tag ("BLOCK_NESTING"))) block;
227 /* For switch (C) or case (Pascal) statements,
228 and also for dummies (see `expand_start_case_dummy'). */
231 /* The insn after which the case dispatch should finally
232 be emitted. Zero for a dummy. */
234 /* A list of case labels; it is first built as an AVL tree.
235 During expand_end_case, this is converted to a list, and may be
236 rearranged into a nearly balanced binary tree. */
237 struct case_node *case_list;
238 /* Label to jump to if no case matches. */
240 /* The expression to be dispatched on. */
242 /* Type that INDEX_EXPR should be converted to. */
244 /* Name of this kind of statement, for warnings. */
245 const char *printname;
246 /* Used to save no_line_numbers till we see the first case label.
247 We set this to -1 when we see the first case label in this
249 int line_number_status;
250 } GTY ((tag ("CASE_NESTING"))) case_stmt;
251 } GTY ((desc ("%1.desc"))) data;
254 /* Allocate and return a new `struct nesting'. */
256 #define ALLOC_NESTING() ggc_alloc (sizeof (struct nesting))
258 /* Pop the nesting stack element by element until we pop off
259 the element which is at the top of STACK.
260 Update all the other stacks, popping off elements from them
261 as we pop them from nesting_stack. */
263 #define POPSTACK(STACK) \
264 do { struct nesting *target = STACK; \
265 struct nesting *this; \
266 do { this = nesting_stack; \
267 if (loop_stack == this) \
268 loop_stack = loop_stack->next; \
269 if (cond_stack == this) \
270 cond_stack = cond_stack->next; \
271 if (block_stack == this) \
272 block_stack = block_stack->next; \
273 if (stack_block_stack == this) \
274 stack_block_stack = stack_block_stack->next; \
275 if (case_stack == this) \
276 case_stack = case_stack->next; \
277 nesting_depth = nesting_stack->depth - 1; \
278 nesting_stack = this->all; } \
279 while (this != target); } while (0)
281 /* In some cases it is impossible to generate code for a forward goto
282 until the label definition is seen. This happens when it may be necessary
283 for the goto to reset the stack pointer: we don't yet know how to do that.
284 So expand_goto puts an entry on this fixup list.
285 Each time a binding contour that resets the stack is exited,
287 If the target label has now been defined, we can insert the proper code. */
289 struct goto_fixup GTY(())
291 /* Points to following fixup. */
292 struct goto_fixup *next;
293 /* Points to the insn before the jump insn.
294 If more code must be inserted, it goes after this insn. */
296 /* The LABEL_DECL that this jump is jumping to, or 0
297 for break, continue or return. */
299 /* The BLOCK for the place where this goto was found. */
301 /* The CODE_LABEL rtx that this is jumping to. */
303 /* Number of binding contours started in current function
304 before the label reference. */
305 int block_start_count;
306 /* The outermost stack level that should be restored for this jump.
307 Each time a binding contour that resets the stack is exited,
308 if the target label is *not* yet defined, this slot is updated. */
310 /* List of lists of cleanup expressions to be run by this goto.
311 There is one element for each block that this goto is within.
312 The tail of this list can be 0,
313 if all remaining elements would be empty.
314 The TREE_VALUE contains the cleanup list of that block as of the
315 time this goto was seen.
316 The TREE_ADDRESSABLE flag is 1 for a block that has been exited. */
317 tree cleanup_list_list;
320 /* Within any binding contour that must restore a stack level,
321 all labels are recorded with a chain of these structures. */
323 struct label_chain GTY(())
325 /* Points to following fixup. */
326 struct label_chain *next;
330 struct stmt_status GTY(())
332 /* Chain of all pending binding contours. */
333 struct nesting * x_block_stack;
335 /* If any new stacks are added here, add them to POPSTACKS too. */
337 /* Chain of all pending binding contours that restore stack levels
339 struct nesting * x_stack_block_stack;
341 /* Chain of all pending conditional statements. */
342 struct nesting * x_cond_stack;
344 /* Chain of all pending loops. */
345 struct nesting * x_loop_stack;
347 /* Chain of all pending case or switch statements. */
348 struct nesting * x_case_stack;
350 /* Separate chain including all of the above,
351 chained through the `all' field. */
352 struct nesting * x_nesting_stack;
354 /* Number of entries on nesting_stack now. */
357 /* Number of binding contours started so far in this function. */
358 int x_block_start_count;
360 /* Each time we expand an expression-statement,
361 record the expr's type and its RTL value here. */
362 tree x_last_expr_type;
363 rtx x_last_expr_value;
365 /* Nonzero if within a ({...}) grouping, in which case we must
366 always compute a value for each expr-stmt in case it is the last one. */
367 int x_expr_stmts_for_value;
369 /* Location of last line-number note, whether we actually
370 emitted it or not. */
371 location_t x_emit_locus;
373 struct goto_fixup *x_goto_fixup_chain;
376 #define block_stack (cfun->stmt->x_block_stack)
377 #define stack_block_stack (cfun->stmt->x_stack_block_stack)
378 #define cond_stack (cfun->stmt->x_cond_stack)
379 #define loop_stack (cfun->stmt->x_loop_stack)
380 #define case_stack (cfun->stmt->x_case_stack)
381 #define nesting_stack (cfun->stmt->x_nesting_stack)
382 #define nesting_depth (cfun->stmt->x_nesting_depth)
383 #define current_block_start_count (cfun->stmt->x_block_start_count)
384 #define last_expr_type (cfun->stmt->x_last_expr_type)
385 #define last_expr_value (cfun->stmt->x_last_expr_value)
386 #define expr_stmts_for_value (cfun->stmt->x_expr_stmts_for_value)
387 #define emit_locus (cfun->stmt->x_emit_locus)
388 #define goto_fixup_chain (cfun->stmt->x_goto_fixup_chain)
390 /* Nonzero if we are using EH to handle cleanups. */
391 static int using_eh_for_cleanups_p = 0;
393 static int n_occurrences (int, const char *);
394 static bool decl_conflicts_with_clobbers_p (tree, const HARD_REG_SET);
395 static void expand_goto_internal (tree, rtx, rtx);
396 static int expand_fixup (tree, rtx, rtx);
397 static rtx expand_nl_handler_label (rtx, rtx);
398 static void expand_nl_goto_receiver (void);
399 static void expand_nl_goto_receivers (struct nesting *);
400 static void fixup_gotos (struct nesting *, rtx, tree, rtx, int);
401 static bool check_operand_nalternatives (tree, tree);
402 static bool check_unique_operand_names (tree, tree);
403 static char *resolve_operand_name_1 (char *, tree, tree);
404 static void expand_null_return_1 (rtx);
405 static enum br_predictor return_prediction (rtx);
406 static rtx shift_return_value (rtx);
407 static void expand_value_return (rtx);
408 static int tail_recursion_args (tree, tree);
409 static void expand_cleanups (tree, int, int);
410 static void check_seenlabel (void);
411 static void do_jump_if_equal (rtx, rtx, rtx, int);
412 static int estimate_case_costs (case_node_ptr);
413 static bool same_case_target_p (rtx, rtx);
414 static void strip_default_case_nodes (case_node_ptr *, rtx);
415 static bool lshift_cheap_p (void);
416 static int case_bit_test_cmp (const void *, const void *);
417 static void emit_case_bit_tests (tree, tree, tree, tree, case_node_ptr, rtx);
418 static void group_case_nodes (case_node_ptr);
419 static void balance_case_nodes (case_node_ptr *, case_node_ptr);
420 static int node_has_low_bound (case_node_ptr, tree);
421 static int node_has_high_bound (case_node_ptr, tree);
422 static int node_is_bounded (case_node_ptr, tree);
423 static void emit_jump_if_reachable (rtx);
424 static void emit_case_nodes (rtx, case_node_ptr, rtx, tree);
425 static struct case_node *case_tree2list (case_node *, case_node *);
428 using_eh_for_cleanups (void)
430 using_eh_for_cleanups_p = 1;
434 init_stmt_for_function (void)
436 cfun->stmt = ggc_alloc_cleared (sizeof (struct stmt_status));
439 /* Record the current file and line. Called from emit_line_note. */
442 set_file_and_line_for_stmt (location_t location)
444 /* If we're outputting an inline function, and we add a line note,
445 there may be no CFUN->STMT information. So, there's no need to
448 emit_locus = location;
451 /* Emit a no-op instruction. */
458 last_insn = get_last_insn ();
460 && (GET_CODE (last_insn) == CODE_LABEL
461 || (GET_CODE (last_insn) == NOTE
462 && prev_real_insn (last_insn) == 0)))
463 emit_insn (gen_nop ());
466 /* Return the rtx-label that corresponds to a LABEL_DECL,
467 creating it if necessary. */
470 label_rtx (tree label)
472 if (TREE_CODE (label) != LABEL_DECL)
475 if (!DECL_RTL_SET_P (label))
476 SET_DECL_RTL (label, gen_label_rtx ());
478 return DECL_RTL (label);
481 /* As above, but also put it on the forced-reference list of the
482 function that contains it. */
484 force_label_rtx (tree label)
486 rtx ref = label_rtx (label);
487 tree function = decl_function_context (label);
493 if (function != current_function_decl
494 && function != inline_function_decl)
495 p = find_function_data (function);
499 p->expr->x_forced_labels = gen_rtx_EXPR_LIST (VOIDmode, ref,
500 p->expr->x_forced_labels);
504 /* Add an unconditional jump to LABEL as the next sequential instruction. */
507 emit_jump (rtx label)
509 do_pending_stack_adjust ();
510 emit_jump_insn (gen_jump (label));
514 /* Emit code to jump to the address
515 specified by the pointer expression EXP. */
518 expand_computed_goto (tree exp)
520 rtx x = expand_expr (exp, NULL_RTX, VOIDmode, 0);
522 x = convert_memory_address (Pmode, x);
526 if (! cfun->computed_goto_common_label)
528 cfun->computed_goto_common_reg = copy_to_mode_reg (Pmode, x);
529 cfun->computed_goto_common_label = gen_label_rtx ();
530 emit_label (cfun->computed_goto_common_label);
532 do_pending_stack_adjust ();
533 emit_indirect_jump (cfun->computed_goto_common_reg);
535 current_function_has_computed_jump = 1;
539 emit_move_insn (cfun->computed_goto_common_reg, x);
540 emit_jump (cfun->computed_goto_common_label);
544 /* Handle goto statements and the labels that they can go to. */
546 /* Specify the location in the RTL code of a label LABEL,
547 which is a LABEL_DECL tree node.
549 This is used for the kind of label that the user can jump to with a
550 goto statement, and for alternatives of a switch or case statement.
551 RTL labels generated for loops and conditionals don't go through here;
552 they are generated directly at the RTL level, by other functions below.
554 Note that this has nothing to do with defining label *names*.
555 Languages vary in how they do that and what that even means. */
558 expand_label (tree label)
560 struct label_chain *p;
562 do_pending_stack_adjust ();
563 emit_label (label_rtx (label));
564 if (DECL_NAME (label))
565 LABEL_NAME (DECL_RTL (label)) = IDENTIFIER_POINTER (DECL_NAME (label));
567 if (stack_block_stack != 0)
569 p = ggc_alloc (sizeof (struct label_chain));
570 p->next = stack_block_stack->data.block.label_chain;
571 stack_block_stack->data.block.label_chain = p;
576 /* Declare that LABEL (a LABEL_DECL) may be used for nonlocal gotos
577 from nested functions. */
580 declare_nonlocal_label (tree label)
582 rtx slot = assign_stack_local (Pmode, GET_MODE_SIZE (Pmode), 0);
584 nonlocal_labels = tree_cons (NULL_TREE, label, nonlocal_labels);
585 LABEL_PRESERVE_P (label_rtx (label)) = 1;
586 if (nonlocal_goto_handler_slots == 0)
588 emit_stack_save (SAVE_NONLOCAL,
589 &nonlocal_goto_stack_level,
590 PREV_INSN (tail_recursion_reentry));
592 nonlocal_goto_handler_slots
593 = gen_rtx_EXPR_LIST (VOIDmode, slot, nonlocal_goto_handler_slots);
596 /* Generate RTL code for a `goto' statement with target label LABEL.
597 LABEL should be a LABEL_DECL tree node that was or will later be
598 defined with `expand_label'. */
601 expand_goto (tree label)
605 /* Check for a nonlocal goto to a containing function. */
606 context = decl_function_context (label);
607 if (context != 0 && context != current_function_decl)
609 struct function *p = find_function_data (context);
610 rtx label_ref = gen_rtx_LABEL_REF (Pmode, label_rtx (label));
611 rtx handler_slot, static_chain, save_area, insn;
614 /* Find the corresponding handler slot for this label. */
615 handler_slot = p->x_nonlocal_goto_handler_slots;
616 for (link = p->x_nonlocal_labels; TREE_VALUE (link) != label;
617 link = TREE_CHAIN (link))
618 handler_slot = XEXP (handler_slot, 1);
619 handler_slot = XEXP (handler_slot, 0);
621 p->has_nonlocal_label = 1;
622 current_function_has_nonlocal_goto = 1;
623 LABEL_REF_NONLOCAL_P (label_ref) = 1;
625 /* Copy the rtl for the slots so that they won't be shared in
626 case the virtual stack vars register gets instantiated differently
627 in the parent than in the child. */
629 static_chain = copy_to_reg (lookup_static_chain (label));
631 /* Get addr of containing function's current nonlocal goto handler,
632 which will do any cleanups and then jump to the label. */
633 handler_slot = copy_to_reg (replace_rtx (copy_rtx (handler_slot),
634 virtual_stack_vars_rtx,
637 /* Get addr of containing function's nonlocal save area. */
638 save_area = p->x_nonlocal_goto_stack_level;
640 save_area = replace_rtx (copy_rtx (save_area),
641 virtual_stack_vars_rtx, static_chain);
643 #if HAVE_nonlocal_goto
644 if (HAVE_nonlocal_goto)
645 emit_insn (gen_nonlocal_goto (static_chain, handler_slot,
646 save_area, label_ref));
650 emit_insn (gen_rtx_CLOBBER (VOIDmode,
651 gen_rtx_MEM (BLKmode,
652 gen_rtx_SCRATCH (VOIDmode))));
653 emit_insn (gen_rtx_CLOBBER (VOIDmode,
654 gen_rtx_MEM (BLKmode,
655 hard_frame_pointer_rtx)));
657 /* Restore frame pointer for containing function.
658 This sets the actual hard register used for the frame pointer
659 to the location of the function's incoming static chain info.
660 The non-local goto handler will then adjust it to contain the
661 proper value and reload the argument pointer, if needed. */
662 emit_move_insn (hard_frame_pointer_rtx, static_chain);
663 emit_stack_restore (SAVE_NONLOCAL, save_area, NULL_RTX);
665 /* USE of hard_frame_pointer_rtx added for consistency;
666 not clear if really needed. */
667 emit_insn (gen_rtx_USE (VOIDmode, hard_frame_pointer_rtx));
668 emit_insn (gen_rtx_USE (VOIDmode, stack_pointer_rtx));
669 emit_indirect_jump (handler_slot);
672 /* Search backwards to the jump insn and mark it as a
674 for (insn = get_last_insn (); insn; insn = PREV_INSN (insn))
676 if (GET_CODE (insn) == JUMP_INSN)
678 REG_NOTES (insn) = alloc_EXPR_LIST (REG_NON_LOCAL_GOTO,
679 const0_rtx, REG_NOTES (insn));
682 else if (GET_CODE (insn) == CALL_INSN)
687 expand_goto_internal (label, label_rtx (label), NULL_RTX);
690 /* Generate RTL code for a `goto' statement with target label BODY.
691 LABEL should be a LABEL_REF.
692 LAST_INSN, if non-0, is the rtx we should consider as the last
693 insn emitted (for the purposes of cleaning up a return). */
696 expand_goto_internal (tree body, rtx label, rtx last_insn)
698 struct nesting *block;
701 if (GET_CODE (label) != CODE_LABEL)
704 /* If label has already been defined, we can tell now
705 whether and how we must alter the stack level. */
707 if (PREV_INSN (label) != 0)
709 /* Find the innermost pending block that contains the label.
710 (Check containment by comparing insn-uids.)
711 Then restore the outermost stack level within that block,
712 and do cleanups of all blocks contained in it. */
713 for (block = block_stack; block; block = block->next)
715 if (INSN_UID (block->data.block.first_insn) < INSN_UID (label))
717 if (block->data.block.stack_level != 0)
718 stack_level = block->data.block.stack_level;
719 /* Execute the cleanups for blocks we are exiting. */
720 if (block->data.block.cleanups != 0)
722 expand_cleanups (block->data.block.cleanups, 1, 1);
723 do_pending_stack_adjust ();
729 /* Ensure stack adjust isn't done by emit_jump, as this
730 would clobber the stack pointer. This one should be
731 deleted as dead by flow. */
732 clear_pending_stack_adjust ();
733 do_pending_stack_adjust ();
735 /* Don't do this adjust if it's to the end label and this function
736 is to return with a depressed stack pointer. */
737 if (label == return_label
738 && (((TREE_CODE (TREE_TYPE (current_function_decl))
740 && (TYPE_RETURNS_STACK_DEPRESSED
741 (TREE_TYPE (current_function_decl))))))
744 emit_stack_restore (SAVE_BLOCK, stack_level, NULL_RTX);
747 if (body != 0 && DECL_TOO_LATE (body))
748 error ("jump to `%s' invalidly jumps into binding contour",
749 IDENTIFIER_POINTER (DECL_NAME (body)));
751 /* Label not yet defined: may need to put this goto
752 on the fixup list. */
753 else if (! expand_fixup (body, label, last_insn))
755 /* No fixup needed. Record that the label is the target
756 of at least one goto that has no fixup. */
758 TREE_ADDRESSABLE (body) = 1;
764 /* Generate if necessary a fixup for a goto
765 whose target label in tree structure (if any) is TREE_LABEL
766 and whose target in rtl is RTL_LABEL.
768 If LAST_INSN is nonzero, we pretend that the jump appears
769 after insn LAST_INSN instead of at the current point in the insn stream.
771 The fixup will be used later to insert insns just before the goto.
772 Those insns will restore the stack level as appropriate for the
773 target label, and will (in the case of C++) also invoke any object
774 destructors which have to be invoked when we exit the scopes which
775 are exited by the goto.
777 Value is nonzero if a fixup is made. */
780 expand_fixup (tree tree_label, rtx rtl_label, rtx last_insn)
782 struct nesting *block, *end_block;
784 /* See if we can recognize which block the label will be output in.
785 This is possible in some very common cases.
786 If we succeed, set END_BLOCK to that block.
787 Otherwise, set it to 0. */
790 && (rtl_label == cond_stack->data.cond.endif_label
791 || rtl_label == cond_stack->data.cond.next_label))
792 end_block = cond_stack;
793 /* If we are in a loop, recognize certain labels which
794 are likely targets. This reduces the number of fixups
795 we need to create. */
797 && (rtl_label == loop_stack->data.loop.start_label
798 || rtl_label == loop_stack->data.loop.end_label
799 || rtl_label == loop_stack->data.loop.continue_label))
800 end_block = loop_stack;
804 /* Now set END_BLOCK to the binding level to which we will return. */
808 struct nesting *next_block = end_block->all;
811 /* First see if the END_BLOCK is inside the innermost binding level.
812 If so, then no cleanups or stack levels are relevant. */
813 while (next_block && next_block != block)
814 next_block = next_block->all;
819 /* Otherwise, set END_BLOCK to the innermost binding level
820 which is outside the relevant control-structure nesting. */
821 next_block = block_stack->next;
822 for (block = block_stack; block != end_block; block = block->all)
823 if (block == next_block)
824 next_block = next_block->next;
825 end_block = next_block;
828 /* Does any containing block have a stack level or cleanups?
829 If not, no fixup is needed, and that is the normal case
830 (the only case, for standard C). */
831 for (block = block_stack; block != end_block; block = block->next)
832 if (block->data.block.stack_level != 0
833 || block->data.block.cleanups != 0)
836 if (block != end_block)
838 /* Ok, a fixup is needed. Add a fixup to the list of such. */
839 struct goto_fixup *fixup = ggc_alloc (sizeof (struct goto_fixup));
840 /* In case an old stack level is restored, make sure that comes
841 after any pending stack adjust. */
842 /* ?? If the fixup isn't to come at the present position,
843 doing the stack adjust here isn't useful. Doing it with our
844 settings at that location isn't useful either. Let's hope
847 do_pending_stack_adjust ();
848 fixup->target = tree_label;
849 fixup->target_rtl = rtl_label;
851 /* Create a BLOCK node and a corresponding matched set of
852 NOTE_INSN_BLOCK_BEG and NOTE_INSN_BLOCK_END notes at
853 this point. The notes will encapsulate any and all fixup
854 code which we might later insert at this point in the insn
855 stream. Also, the BLOCK node will be the parent (i.e. the
856 `SUPERBLOCK') of any other BLOCK nodes which we might create
857 later on when we are expanding the fixup code.
859 Note that optimization passes (including expand_end_loop)
860 might move the *_BLOCK notes away, so we use a NOTE_INSN_DELETED
864 rtx original_before_jump
865 = last_insn ? last_insn : get_last_insn ();
870 block = make_node (BLOCK);
871 TREE_USED (block) = 1;
873 if (!cfun->x_whole_function_mode_p)
874 (*lang_hooks.decls.insert_block) (block);
878 = BLOCK_CHAIN (DECL_INITIAL (current_function_decl));
879 BLOCK_CHAIN (DECL_INITIAL (current_function_decl))
884 start = emit_note (NOTE_INSN_BLOCK_BEG);
885 if (cfun->x_whole_function_mode_p)
886 NOTE_BLOCK (start) = block;
887 fixup->before_jump = emit_note (NOTE_INSN_DELETED);
888 end = emit_note (NOTE_INSN_BLOCK_END);
889 if (cfun->x_whole_function_mode_p)
890 NOTE_BLOCK (end) = block;
891 fixup->context = block;
893 emit_insn_after (start, original_before_jump);
896 fixup->block_start_count = current_block_start_count;
897 fixup->stack_level = 0;
898 fixup->cleanup_list_list
899 = ((block->data.block.outer_cleanups
900 || block->data.block.cleanups)
901 ? tree_cons (NULL_TREE, block->data.block.cleanups,
902 block->data.block.outer_cleanups)
904 fixup->next = goto_fixup_chain;
905 goto_fixup_chain = fixup;
911 /* Expand any needed fixups in the outputmost binding level of the
912 function. FIRST_INSN is the first insn in the function. */
915 expand_fixups (rtx first_insn)
917 fixup_gotos (NULL, NULL_RTX, NULL_TREE, first_insn, 0);
920 /* When exiting a binding contour, process all pending gotos requiring fixups.
921 THISBLOCK is the structure that describes the block being exited.
922 STACK_LEVEL is the rtx for the stack level to restore exiting this contour.
923 CLEANUP_LIST is a list of expressions to evaluate on exiting this contour.
924 FIRST_INSN is the insn that began this contour.
926 Gotos that jump out of this contour must restore the
927 stack level and do the cleanups before actually jumping.
929 DONT_JUMP_IN positive means report error if there is a jump into this
930 contour from before the beginning of the contour. This is also done if
931 STACK_LEVEL is nonzero unless DONT_JUMP_IN is negative. */
934 fixup_gotos (struct nesting *thisblock, rtx stack_level,
935 tree cleanup_list, rtx first_insn, int dont_jump_in)
937 struct goto_fixup *f, *prev;
939 /* F is the fixup we are considering; PREV is the previous one. */
940 /* We run this loop in two passes so that cleanups of exited blocks
941 are run first, and blocks that are exited are marked so
944 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
946 /* Test for a fixup that is inactive because it is already handled. */
947 if (f->before_jump == 0)
949 /* Delete inactive fixup from the chain, if that is easy to do. */
951 prev->next = f->next;
953 /* Has this fixup's target label been defined?
954 If so, we can finalize it. */
955 else if (PREV_INSN (f->target_rtl) != 0)
959 /* If this fixup jumped into this contour from before the beginning
960 of this contour, report an error. This code used to use
961 the first non-label insn after f->target_rtl, but that's
962 wrong since such can be added, by things like put_var_into_stack
963 and have INSN_UIDs that are out of the range of the block. */
964 /* ??? Bug: this does not detect jumping in through intermediate
965 blocks that have stack levels or cleanups.
966 It detects only a problem with the innermost block
969 && (dont_jump_in > 0 || (dont_jump_in == 0 && stack_level)
971 && INSN_UID (first_insn) < INSN_UID (f->target_rtl)
972 && INSN_UID (first_insn) > INSN_UID (f->before_jump)
973 && ! DECL_ERROR_ISSUED (f->target))
975 error ("%Jlabel '%D' used before containing binding contour",
976 f->target, f->target);
977 /* Prevent multiple errors for one label. */
978 DECL_ERROR_ISSUED (f->target) = 1;
981 /* We will expand the cleanups into a sequence of their own and
982 then later on we will attach this new sequence to the insn
983 stream just ahead of the actual jump insn. */
987 /* Temporarily restore the lexical context where we will
988 logically be inserting the fixup code. We do this for the
989 sake of getting the debugging information right. */
991 (*lang_hooks.decls.pushlevel) (0);
992 (*lang_hooks.decls.set_block) (f->context);
994 /* Expand the cleanups for blocks this jump exits. */
995 if (f->cleanup_list_list)
998 for (lists = f->cleanup_list_list; lists; lists = TREE_CHAIN (lists))
999 /* Marked elements correspond to blocks that have been closed.
1000 Do their cleanups. */
1001 if (TREE_ADDRESSABLE (lists)
1002 && TREE_VALUE (lists) != 0)
1004 expand_cleanups (TREE_VALUE (lists), 1, 1);
1005 /* Pop any pushes done in the cleanups,
1006 in case function is about to return. */
1007 do_pending_stack_adjust ();
1011 /* Restore stack level for the biggest contour that this
1012 jump jumps out of. */
1014 && ! (f->target_rtl == return_label
1015 && ((TREE_CODE (TREE_TYPE (current_function_decl))
1017 && (TYPE_RETURNS_STACK_DEPRESSED
1018 (TREE_TYPE (current_function_decl))))))
1019 emit_stack_restore (SAVE_BLOCK, f->stack_level, f->before_jump);
1021 /* Finish up the sequence containing the insns which implement the
1022 necessary cleanups, and then attach that whole sequence to the
1023 insn stream just ahead of the actual jump insn. Attaching it
1024 at that point insures that any cleanups which are in fact
1025 implicit C++ object destructions (which must be executed upon
1026 leaving the block) appear (to the debugger) to be taking place
1027 in an area of the generated code where the object(s) being
1028 destructed are still "in scope". */
1030 cleanup_insns = get_insns ();
1031 (*lang_hooks.decls.poplevel) (1, 0, 0);
1034 emit_insn_after (cleanup_insns, f->before_jump);
1040 /* For any still-undefined labels, do the cleanups for this block now.
1041 We must do this now since items in the cleanup list may go out
1042 of scope when the block ends. */
1043 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
1044 if (f->before_jump != 0
1045 && PREV_INSN (f->target_rtl) == 0
1046 /* Label has still not appeared. If we are exiting a block with
1047 a stack level to restore, that started before the fixup,
1048 mark this stack level as needing restoration
1049 when the fixup is later finalized. */
1051 /* Note: if THISBLOCK == 0 and we have a label that hasn't appeared, it
1052 means the label is undefined. That's erroneous, but possible. */
1053 && (thisblock->data.block.block_start_count
1054 <= f->block_start_count))
1056 tree lists = f->cleanup_list_list;
1059 for (; lists; lists = TREE_CHAIN (lists))
1060 /* If the following elt. corresponds to our containing block
1061 then the elt. must be for this block. */
1062 if (TREE_CHAIN (lists) == thisblock->data.block.outer_cleanups)
1065 (*lang_hooks.decls.pushlevel) (0);
1066 (*lang_hooks.decls.set_block) (f->context);
1067 expand_cleanups (TREE_VALUE (lists), 1, 1);
1068 do_pending_stack_adjust ();
1069 cleanup_insns = get_insns ();
1070 (*lang_hooks.decls.poplevel) (1, 0, 0);
1072 if (cleanup_insns != 0)
1074 = emit_insn_after (cleanup_insns, f->before_jump);
1076 f->cleanup_list_list = TREE_CHAIN (lists);
1080 f->stack_level = stack_level;
1084 /* Return the number of times character C occurs in string S. */
1086 n_occurrences (int c, const char *s)
1094 /* Generate RTL for an asm statement (explicit assembler code).
1095 STRING is a STRING_CST node containing the assembler code text,
1096 or an ADDR_EXPR containing a STRING_CST. VOL nonzero means the
1097 insn is volatile; don't optimize it. */
1100 expand_asm (tree string, int vol)
1104 if (TREE_CODE (string) == ADDR_EXPR)
1105 string = TREE_OPERAND (string, 0);
1107 body = gen_rtx_ASM_INPUT (VOIDmode, TREE_STRING_POINTER (string));
1109 MEM_VOLATILE_P (body) = vol;
1116 /* Parse the output constraint pointed to by *CONSTRAINT_P. It is the
1117 OPERAND_NUMth output operand, indexed from zero. There are NINPUTS
1118 inputs and NOUTPUTS outputs to this extended-asm. Upon return,
1119 *ALLOWS_MEM will be TRUE iff the constraint allows the use of a
1120 memory operand. Similarly, *ALLOWS_REG will be TRUE iff the
1121 constraint allows the use of a register operand. And, *IS_INOUT
1122 will be true if the operand is read-write, i.e., if it is used as
1123 an input as well as an output. If *CONSTRAINT_P is not in
1124 canonical form, it will be made canonical. (Note that `+' will be
1125 replaced with `=' as part of this process.)
1127 Returns TRUE if all went well; FALSE if an error occurred. */
1130 parse_output_constraint (const char **constraint_p, int operand_num,
1131 int ninputs, int noutputs, bool *allows_mem,
1132 bool *allows_reg, bool *is_inout)
1134 const char *constraint = *constraint_p;
1137 /* Assume the constraint doesn't allow the use of either a register
1139 *allows_mem = false;
1140 *allows_reg = false;
1142 /* Allow the `=' or `+' to not be at the beginning of the string,
1143 since it wasn't explicitly documented that way, and there is a
1144 large body of code that puts it last. Swap the character to
1145 the front, so as not to uglify any place else. */
1146 p = strchr (constraint, '=');
1148 p = strchr (constraint, '+');
1150 /* If the string doesn't contain an `=', issue an error
1154 error ("output operand constraint lacks `='");
1158 /* If the constraint begins with `+', then the operand is both read
1159 from and written to. */
1160 *is_inout = (*p == '+');
1162 /* Canonicalize the output constraint so that it begins with `='. */
1163 if (p != constraint || is_inout)
1166 size_t c_len = strlen (constraint);
1168 if (p != constraint)
1169 warning ("output constraint `%c' for operand %d is not at the beginning",
1172 /* Make a copy of the constraint. */
1173 buf = alloca (c_len + 1);
1174 strcpy (buf, constraint);
1175 /* Swap the first character and the `=' or `+'. */
1176 buf[p - constraint] = buf[0];
1177 /* Make sure the first character is an `='. (Until we do this,
1178 it might be a `+'.) */
1180 /* Replace the constraint with the canonicalized string. */
1181 *constraint_p = ggc_alloc_string (buf, c_len);
1182 constraint = *constraint_p;
1185 /* Loop through the constraint string. */
1186 for (p = constraint + 1; *p; p += CONSTRAINT_LEN (*p, p))
1191 error ("operand constraint contains incorrectly positioned '+' or '='");
1195 if (operand_num + 1 == ninputs + noutputs)
1197 error ("`%%' constraint used with last operand");
1202 case 'V': case 'm': case 'o':
1206 case '?': case '!': case '*': case '&': case '#':
1207 case 'E': case 'F': case 'G': case 'H':
1208 case 's': case 'i': case 'n':
1209 case 'I': case 'J': case 'K': case 'L': case 'M':
1210 case 'N': case 'O': case 'P': case ',':
1213 case '0': case '1': case '2': case '3': case '4':
1214 case '5': case '6': case '7': case '8': case '9':
1216 error ("matching constraint not valid in output operand");
1220 /* ??? Before flow, auto inc/dec insns are not supposed to exist,
1221 excepting those that expand_call created. So match memory
1238 if (REG_CLASS_FROM_CONSTRAINT (*p, p) != NO_REGS)
1240 #ifdef EXTRA_CONSTRAINT_STR
1241 else if (EXTRA_ADDRESS_CONSTRAINT (*p, p))
1243 else if (EXTRA_MEMORY_CONSTRAINT (*p, p))
1247 /* Otherwise we can't assume anything about the nature of
1248 the constraint except that it isn't purely registers.
1249 Treat it like "g" and hope for the best. */
1260 /* Similar, but for input constraints. */
1263 parse_input_constraint (const char **constraint_p, int input_num,
1264 int ninputs, int noutputs, int ninout,
1265 const char * const * constraints,
1266 bool *allows_mem, bool *allows_reg)
1268 const char *constraint = *constraint_p;
1269 const char *orig_constraint = constraint;
1270 size_t c_len = strlen (constraint);
1273 /* Assume the constraint doesn't allow the use of either
1274 a register or memory. */
1275 *allows_mem = false;
1276 *allows_reg = false;
1278 /* Make sure constraint has neither `=', `+', nor '&'. */
1280 for (j = 0; j < c_len; j += CONSTRAINT_LEN (constraint[j], constraint+j))
1281 switch (constraint[j])
1283 case '+': case '=': case '&':
1284 if (constraint == orig_constraint)
1286 error ("input operand constraint contains `%c'", constraint[j]);
1292 if (constraint == orig_constraint
1293 && input_num + 1 == ninputs - ninout)
1295 error ("`%%' constraint used with last operand");
1300 case 'V': case 'm': case 'o':
1305 case '?': case '!': case '*': case '#':
1306 case 'E': case 'F': case 'G': case 'H':
1307 case 's': case 'i': case 'n':
1308 case 'I': case 'J': case 'K': case 'L': case 'M':
1309 case 'N': case 'O': case 'P': case ',':
1312 /* Whether or not a numeric constraint allows a register is
1313 decided by the matching constraint, and so there is no need
1314 to do anything special with them. We must handle them in
1315 the default case, so that we don't unnecessarily force
1316 operands to memory. */
1317 case '0': case '1': case '2': case '3': case '4':
1318 case '5': case '6': case '7': case '8': case '9':
1321 unsigned long match;
1323 match = strtoul (constraint + j, &end, 10);
1324 if (match >= (unsigned long) noutputs)
1326 error ("matching constraint references invalid operand number");
1330 /* Try and find the real constraint for this dup. Only do this
1331 if the matching constraint is the only alternative. */
1333 && (j == 0 || (j == 1 && constraint[0] == '%')))
1335 constraint = constraints[match];
1336 *constraint_p = constraint;
1337 c_len = strlen (constraint);
1339 /* ??? At the end of the loop, we will skip the first part of
1340 the matched constraint. This assumes not only that the
1341 other constraint is an output constraint, but also that
1342 the '=' or '+' come first. */
1346 j = end - constraint;
1347 /* Anticipate increment at end of loop. */
1362 if (! ISALPHA (constraint[j]))
1364 error ("invalid punctuation `%c' in constraint", constraint[j]);
1367 if (REG_CLASS_FROM_CONSTRAINT (constraint[j], constraint + j)
1370 #ifdef EXTRA_CONSTRAINT_STR
1371 else if (EXTRA_ADDRESS_CONSTRAINT (constraint[j], constraint + j))
1373 else if (EXTRA_MEMORY_CONSTRAINT (constraint[j], constraint + j))
1377 /* Otherwise we can't assume anything about the nature of
1378 the constraint except that it isn't purely registers.
1379 Treat it like "g" and hope for the best. */
1390 /* Check for overlap between registers marked in CLOBBERED_REGS and
1391 anything inappropriate in DECL. Emit error and return TRUE for error,
1395 decl_conflicts_with_clobbers_p (tree decl, const HARD_REG_SET clobbered_regs)
1397 /* Conflicts between asm-declared register variables and the clobber
1398 list are not allowed. */
1399 if ((TREE_CODE (decl) == VAR_DECL || TREE_CODE (decl) == PARM_DECL)
1400 && DECL_REGISTER (decl)
1401 && REG_P (DECL_RTL (decl))
1402 && REGNO (DECL_RTL (decl)) < FIRST_PSEUDO_REGISTER)
1404 rtx reg = DECL_RTL (decl);
1407 for (regno = REGNO (reg);
1408 regno < (REGNO (reg)
1409 + HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg)));
1411 if (TEST_HARD_REG_BIT (clobbered_regs, regno))
1413 error ("asm-specifier for variable `%s' conflicts with asm clobber list",
1414 IDENTIFIER_POINTER (DECL_NAME (decl)));
1416 /* Reset registerness to stop multiple errors emitted for a
1418 DECL_REGISTER (decl) = 0;
1425 /* Generate RTL for an asm statement with arguments.
1426 STRING is the instruction template.
1427 OUTPUTS is a list of output arguments (lvalues); INPUTS a list of inputs.
1428 Each output or input has an expression in the TREE_VALUE and
1429 and a tree list in TREE_PURPOSE which in turn contains a constraint
1430 name in TREE_VALUE (or NULL_TREE) and a constraint string
1432 CLOBBERS is a list of STRING_CST nodes each naming a hard register
1433 that is clobbered by this insn.
1435 Not all kinds of lvalue that may appear in OUTPUTS can be stored directly.
1436 Some elements of OUTPUTS may be replaced with trees representing temporary
1437 values. The caller should copy those temporary values to the originally
1440 VOL nonzero means the insn is volatile; don't optimize it. */
1443 expand_asm_operands (tree string, tree outputs, tree inputs,
1444 tree clobbers, int vol, location_t locus)
1446 rtvec argvec, constraintvec;
1448 int ninputs = list_length (inputs);
1449 int noutputs = list_length (outputs);
1452 HARD_REG_SET clobbered_regs;
1453 int clobber_conflict_found = 0;
1457 /* Vector of RTX's of evaluated output operands. */
1458 rtx *output_rtx = alloca (noutputs * sizeof (rtx));
1459 int *inout_opnum = alloca (noutputs * sizeof (int));
1460 rtx *real_output_rtx = alloca (noutputs * sizeof (rtx));
1461 enum machine_mode *inout_mode
1462 = alloca (noutputs * sizeof (enum machine_mode));
1463 const char **constraints
1464 = alloca ((noutputs + ninputs) * sizeof (const char *));
1465 int old_generating_concat_p = generating_concat_p;
1467 /* An ASM with no outputs needs to be treated as volatile, for now. */
1471 if (! check_operand_nalternatives (outputs, inputs))
1474 string = resolve_asm_operand_names (string, outputs, inputs);
1476 /* Collect constraints. */
1478 for (t = outputs; t ; t = TREE_CHAIN (t), i++)
1479 constraints[i] = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
1480 for (t = inputs; t ; t = TREE_CHAIN (t), i++)
1481 constraints[i] = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
1483 #ifdef MD_ASM_CLOBBERS
1484 /* Sometimes we wish to automatically clobber registers across an asm.
1485 Case in point is when the i386 backend moved from cc0 to a hard reg --
1486 maintaining source-level compatibility means automatically clobbering
1487 the flags register. */
1488 MD_ASM_CLOBBERS (clobbers);
1491 /* Count the number of meaningful clobbered registers, ignoring what
1492 we would ignore later. */
1494 CLEAR_HARD_REG_SET (clobbered_regs);
1495 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1497 const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1499 i = decode_reg_name (regname);
1500 if (i >= 0 || i == -4)
1503 error ("unknown register name `%s' in `asm'", regname);
1505 /* Mark clobbered registers. */
1508 /* Clobbering the PIC register is an error */
1509 if (i == (int) PIC_OFFSET_TABLE_REGNUM)
1511 error ("PIC register `%s' clobbered in `asm'", regname);
1515 SET_HARD_REG_BIT (clobbered_regs, i);
1521 /* First pass over inputs and outputs checks validity and sets
1522 mark_addressable if needed. */
1525 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1527 tree val = TREE_VALUE (tail);
1528 tree type = TREE_TYPE (val);
1529 const char *constraint;
1534 /* If there's an erroneous arg, emit no insn. */
1535 if (type == error_mark_node)
1538 /* Try to parse the output constraint. If that fails, there's
1539 no point in going further. */
1540 constraint = constraints[i];
1541 if (!parse_output_constraint (&constraint, i, ninputs, noutputs,
1542 &allows_mem, &allows_reg, &is_inout))
1549 && GET_CODE (DECL_RTL (val)) == REG
1550 && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type))))
1551 (*lang_hooks.mark_addressable) (val);
1558 if (ninputs + noutputs > MAX_RECOG_OPERANDS)
1560 error ("more than %d operands in `asm'", MAX_RECOG_OPERANDS);
1564 for (i = 0, tail = inputs; tail; i++, tail = TREE_CHAIN (tail))
1566 bool allows_reg, allows_mem;
1567 const char *constraint;
1569 /* If there's an erroneous arg, emit no insn, because the ASM_INPUT
1570 would get VOIDmode and that could cause a crash in reload. */
1571 if (TREE_TYPE (TREE_VALUE (tail)) == error_mark_node)
1574 constraint = constraints[i + noutputs];
1575 if (! parse_input_constraint (&constraint, i, ninputs, noutputs, ninout,
1576 constraints, &allows_mem, &allows_reg))
1579 if (! allows_reg && allows_mem)
1580 (*lang_hooks.mark_addressable) (TREE_VALUE (tail));
1583 /* Second pass evaluates arguments. */
1586 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1588 tree val = TREE_VALUE (tail);
1589 tree type = TREE_TYPE (val);
1595 if (!parse_output_constraint (&constraints[i], i, ninputs,
1596 noutputs, &allows_mem, &allows_reg,
1600 /* If an output operand is not a decl or indirect ref and our constraint
1601 allows a register, make a temporary to act as an intermediate.
1602 Make the asm insn write into that, then our caller will copy it to
1603 the real output operand. Likewise for promoted variables. */
1605 generating_concat_p = 0;
1607 real_output_rtx[i] = NULL_RTX;
1608 if ((TREE_CODE (val) == INDIRECT_REF
1611 && (allows_mem || GET_CODE (DECL_RTL (val)) == REG)
1612 && ! (GET_CODE (DECL_RTL (val)) == REG
1613 && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type)))
1617 op = expand_expr (val, NULL_RTX, VOIDmode, EXPAND_WRITE);
1618 if (GET_CODE (op) == MEM)
1619 op = validize_mem (op);
1621 if (! allows_reg && GET_CODE (op) != MEM)
1622 error ("output number %d not directly addressable", i);
1623 if ((! allows_mem && GET_CODE (op) == MEM)
1624 || GET_CODE (op) == CONCAT)
1626 real_output_rtx[i] = protect_from_queue (op, 1);
1627 op = gen_reg_rtx (GET_MODE (op));
1629 emit_move_insn (op, real_output_rtx[i]);
1634 op = assign_temp (type, 0, 0, 1);
1635 op = validize_mem (op);
1636 TREE_VALUE (tail) = make_tree (type, op);
1640 generating_concat_p = old_generating_concat_p;
1644 inout_mode[ninout] = TYPE_MODE (type);
1645 inout_opnum[ninout++] = i;
1648 if (decl_conflicts_with_clobbers_p (val, clobbered_regs))
1649 clobber_conflict_found = 1;
1652 /* Make vectors for the expression-rtx, constraint strings,
1653 and named operands. */
1655 argvec = rtvec_alloc (ninputs);
1656 constraintvec = rtvec_alloc (ninputs);
1658 body = gen_rtx_ASM_OPERANDS ((noutputs == 0 ? VOIDmode
1659 : GET_MODE (output_rtx[0])),
1660 TREE_STRING_POINTER (string),
1661 empty_string, 0, argvec, constraintvec,
1662 locus.file, locus.line);
1664 MEM_VOLATILE_P (body) = vol;
1666 /* Eval the inputs and put them into ARGVEC.
1667 Put their constraints into ASM_INPUTs and store in CONSTRAINTS. */
1669 for (i = 0, tail = inputs; tail; tail = TREE_CHAIN (tail), ++i)
1671 bool allows_reg, allows_mem;
1672 const char *constraint;
1676 constraint = constraints[i + noutputs];
1677 if (! parse_input_constraint (&constraint, i, ninputs, noutputs, ninout,
1678 constraints, &allows_mem, &allows_reg))
1681 generating_concat_p = 0;
1683 val = TREE_VALUE (tail);
1684 type = TREE_TYPE (val);
1685 op = expand_expr (val, NULL_RTX, VOIDmode,
1686 (allows_mem && !allows_reg
1687 ? EXPAND_MEMORY : EXPAND_NORMAL));
1689 /* Never pass a CONCAT to an ASM. */
1690 if (GET_CODE (op) == CONCAT)
1691 op = force_reg (GET_MODE (op), op);
1692 else if (GET_CODE (op) == MEM)
1693 op = validize_mem (op);
1695 if (asm_operand_ok (op, constraint) <= 0)
1698 op = force_reg (TYPE_MODE (type), op);
1699 else if (!allows_mem)
1700 warning ("asm operand %d probably doesn't match constraints",
1702 else if (GET_CODE (op) == MEM)
1704 /* We won't recognize either volatile memory or memory
1705 with a queued address as available a memory_operand
1706 at this point. Ignore it: clearly this *is* a memory. */
1710 warning ("use of memory input without lvalue in "
1711 "asm operand %d is deprecated", i + noutputs);
1713 if (CONSTANT_P (op))
1715 rtx mem = force_const_mem (TYPE_MODE (type), op);
1717 op = validize_mem (mem);
1719 op = force_reg (TYPE_MODE (type), op);
1721 if (GET_CODE (op) == REG
1722 || GET_CODE (op) == SUBREG
1723 || GET_CODE (op) == ADDRESSOF
1724 || GET_CODE (op) == CONCAT)
1726 tree qual_type = build_qualified_type (type,
1728 | TYPE_QUAL_CONST));
1729 rtx memloc = assign_temp (qual_type, 1, 1, 1);
1730 memloc = validize_mem (memloc);
1731 emit_move_insn (memloc, op);
1737 generating_concat_p = old_generating_concat_p;
1738 ASM_OPERANDS_INPUT (body, i) = op;
1740 ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, i)
1741 = gen_rtx_ASM_INPUT (TYPE_MODE (type), constraints[i + noutputs]);
1743 if (decl_conflicts_with_clobbers_p (val, clobbered_regs))
1744 clobber_conflict_found = 1;
1747 /* Protect all the operands from the queue now that they have all been
1750 generating_concat_p = 0;
1752 for (i = 0; i < ninputs - ninout; i++)
1753 ASM_OPERANDS_INPUT (body, i)
1754 = protect_from_queue (ASM_OPERANDS_INPUT (body, i), 0);
1756 for (i = 0; i < noutputs; i++)
1757 output_rtx[i] = protect_from_queue (output_rtx[i], 1);
1759 /* For in-out operands, copy output rtx to input rtx. */
1760 for (i = 0; i < ninout; i++)
1762 int j = inout_opnum[i];
1765 ASM_OPERANDS_INPUT (body, ninputs - ninout + i)
1768 sprintf (buffer, "%d", j);
1769 ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, ninputs - ninout + i)
1770 = gen_rtx_ASM_INPUT (inout_mode[i], ggc_strdup (buffer));
1773 generating_concat_p = old_generating_concat_p;
1775 /* Now, for each output, construct an rtx
1776 (set OUTPUT (asm_operands INSN OUTPUTCONSTRAINT OUTPUTNUMBER
1777 ARGVEC CONSTRAINTS OPNAMES))
1778 If there is more than one, put them inside a PARALLEL. */
1780 if (noutputs == 1 && nclobbers == 0)
1782 ASM_OPERANDS_OUTPUT_CONSTRAINT (body) = constraints[0];
1783 emit_insn (gen_rtx_SET (VOIDmode, output_rtx[0], body));
1786 else if (noutputs == 0 && nclobbers == 0)
1788 /* No output operands: put in a raw ASM_OPERANDS rtx. */
1800 body = gen_rtx_PARALLEL (VOIDmode, rtvec_alloc (num + nclobbers));
1802 /* For each output operand, store a SET. */
1803 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1805 XVECEXP (body, 0, i)
1806 = gen_rtx_SET (VOIDmode,
1808 gen_rtx_ASM_OPERANDS
1809 (GET_MODE (output_rtx[i]),
1810 TREE_STRING_POINTER (string),
1811 constraints[i], i, argvec, constraintvec,
1812 locus.file, locus.line));
1814 MEM_VOLATILE_P (SET_SRC (XVECEXP (body, 0, i))) = vol;
1817 /* If there are no outputs (but there are some clobbers)
1818 store the bare ASM_OPERANDS into the PARALLEL. */
1821 XVECEXP (body, 0, i++) = obody;
1823 /* Store (clobber REG) for each clobbered register specified. */
1825 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1827 const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1828 int j = decode_reg_name (regname);
1833 if (j == -3) /* `cc', which is not a register */
1836 if (j == -4) /* `memory', don't cache memory across asm */
1838 XVECEXP (body, 0, i++)
1839 = gen_rtx_CLOBBER (VOIDmode,
1842 gen_rtx_SCRATCH (VOIDmode)));
1846 /* Ignore unknown register, error already signaled. */
1850 /* Use QImode since that's guaranteed to clobber just one reg. */
1851 clobbered_reg = gen_rtx_REG (QImode, j);
1853 /* Do sanity check for overlap between clobbers and respectively
1854 input and outputs that hasn't been handled. Such overlap
1855 should have been detected and reported above. */
1856 if (!clobber_conflict_found)
1860 /* We test the old body (obody) contents to avoid tripping
1861 over the under-construction body. */
1862 for (opno = 0; opno < noutputs; opno++)
1863 if (reg_overlap_mentioned_p (clobbered_reg, output_rtx[opno]))
1864 internal_error ("asm clobber conflict with output operand");
1866 for (opno = 0; opno < ninputs - ninout; opno++)
1867 if (reg_overlap_mentioned_p (clobbered_reg,
1868 ASM_OPERANDS_INPUT (obody, opno)))
1869 internal_error ("asm clobber conflict with input operand");
1872 XVECEXP (body, 0, i++)
1873 = gen_rtx_CLOBBER (VOIDmode, clobbered_reg);
1879 /* For any outputs that needed reloading into registers, spill them
1880 back to where they belong. */
1881 for (i = 0; i < noutputs; ++i)
1882 if (real_output_rtx[i])
1883 emit_move_insn (real_output_rtx[i], output_rtx[i]);
1888 /* A subroutine of expand_asm_operands. Check that all operands have
1889 the same number of alternatives. Return true if so. */
1892 check_operand_nalternatives (tree outputs, tree inputs)
1894 if (outputs || inputs)
1896 tree tmp = TREE_PURPOSE (outputs ? outputs : inputs);
1898 = n_occurrences (',', TREE_STRING_POINTER (TREE_VALUE (tmp)));
1901 if (nalternatives + 1 > MAX_RECOG_ALTERNATIVES)
1903 error ("too many alternatives in `asm'");
1910 const char *constraint
1911 = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tmp)));
1913 if (n_occurrences (',', constraint) != nalternatives)
1915 error ("operand constraints for `asm' differ in number of alternatives");
1919 if (TREE_CHAIN (tmp))
1920 tmp = TREE_CHAIN (tmp);
1922 tmp = next, next = 0;
1929 /* A subroutine of expand_asm_operands. Check that all operand names
1930 are unique. Return true if so. We rely on the fact that these names
1931 are identifiers, and so have been canonicalized by get_identifier,
1932 so all we need are pointer comparisons. */
1935 check_unique_operand_names (tree outputs, tree inputs)
1939 for (i = outputs; i ; i = TREE_CHAIN (i))
1941 tree i_name = TREE_PURPOSE (TREE_PURPOSE (i));
1945 for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
1946 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1950 for (i = inputs; i ; i = TREE_CHAIN (i))
1952 tree i_name = TREE_PURPOSE (TREE_PURPOSE (i));
1956 for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
1957 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1959 for (j = outputs; j ; j = TREE_CHAIN (j))
1960 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1967 error ("duplicate asm operand name '%s'",
1968 TREE_STRING_POINTER (TREE_PURPOSE (TREE_PURPOSE (i))));
1972 /* A subroutine of expand_asm_operands. Resolve the names of the operands
1973 in *POUTPUTS and *PINPUTS to numbers, and replace the name expansions in
1974 STRING and in the constraints to those numbers. */
1977 resolve_asm_operand_names (tree string, tree outputs, tree inputs)
1984 check_unique_operand_names (outputs, inputs);
1986 /* Substitute [<name>] in input constraint strings. There should be no
1987 named operands in output constraints. */
1988 for (t = inputs; t ; t = TREE_CHAIN (t))
1990 c = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
1991 if (strchr (c, '[') != NULL)
1993 p = buffer = xstrdup (c);
1994 while ((p = strchr (p, '[')) != NULL)
1995 p = resolve_operand_name_1 (p, outputs, inputs);
1996 TREE_VALUE (TREE_PURPOSE (t))
1997 = build_string (strlen (buffer), buffer);
2002 /* Now check for any needed substitutions in the template. */
2003 c = TREE_STRING_POINTER (string);
2004 while ((c = strchr (c, '%')) != NULL)
2008 else if (ISALPHA (c[1]) && c[2] == '[')
2019 /* OK, we need to make a copy so we can perform the substitutions.
2020 Assume that we will not need extra space--we get to remove '['
2021 and ']', which means we cannot have a problem until we have more
2022 than 999 operands. */
2023 buffer = xstrdup (TREE_STRING_POINTER (string));
2024 p = buffer + (c - TREE_STRING_POINTER (string));
2026 while ((p = strchr (p, '%')) != NULL)
2030 else if (ISALPHA (p[1]) && p[2] == '[')
2038 p = resolve_operand_name_1 (p, outputs, inputs);
2041 string = build_string (strlen (buffer), buffer);
2048 /* A subroutine of resolve_operand_names. P points to the '[' for a
2049 potential named operand of the form [<name>]. In place, replace
2050 the name and brackets with a number. Return a pointer to the
2051 balance of the string after substitution. */
2054 resolve_operand_name_1 (char *p, tree outputs, tree inputs)
2061 /* Collect the operand name. */
2062 q = strchr (p, ']');
2065 error ("missing close brace for named operand");
2066 return strchr (p, '\0');
2070 /* Resolve the name to a number. */
2071 for (op = 0, t = outputs; t ; t = TREE_CHAIN (t), op++)
2073 tree name = TREE_PURPOSE (TREE_PURPOSE (t));
2076 const char *c = TREE_STRING_POINTER (name);
2077 if (strncmp (c, p + 1, len) == 0 && c[len] == '\0')
2081 for (t = inputs; t ; t = TREE_CHAIN (t), op++)
2083 tree name = TREE_PURPOSE (TREE_PURPOSE (t));
2086 const char *c = TREE_STRING_POINTER (name);
2087 if (strncmp (c, p + 1, len) == 0 && c[len] == '\0')
2093 error ("undefined named operand '%s'", p + 1);
2097 /* Replace the name with the number. Unfortunately, not all libraries
2098 get the return value of sprintf correct, so search for the end of the
2099 generated string by hand. */
2100 sprintf (p, "%d", op);
2101 p = strchr (p, '\0');
2103 /* Verify the no extra buffer space assumption. */
2107 /* Shift the rest of the buffer down to fill the gap. */
2108 memmove (p, q + 1, strlen (q + 1) + 1);
2113 /* Generate RTL to evaluate the expression EXP
2114 and remember it in case this is the VALUE in a ({... VALUE; }) constr.
2115 Provided just for backward-compatibility. expand_expr_stmt_value()
2116 should be used for new code. */
2119 expand_expr_stmt (tree exp)
2121 expand_expr_stmt_value (exp, -1, 1);
2124 /* Generate RTL to evaluate the expression EXP. WANT_VALUE tells
2125 whether to (1) save the value of the expression, (0) discard it or
2126 (-1) use expr_stmts_for_value to tell. The use of -1 is
2127 deprecated, and retained only for backward compatibility. */
2130 expand_expr_stmt_value (tree exp, int want_value, int maybe_last)
2135 if (want_value == -1)
2136 want_value = expr_stmts_for_value != 0;
2138 /* If -Wextra, warn about statements with no side effects,
2139 except for an explicit cast to void (e.g. for assert()), and
2140 except for last statement in ({...}) where they may be useful. */
2142 && (expr_stmts_for_value == 0 || ! maybe_last)
2143 && exp != error_mark_node
2144 && warn_unused_value)
2146 if (TREE_SIDE_EFFECTS (exp))
2147 warn_if_unused_value (exp);
2148 else if (!VOID_TYPE_P (TREE_TYPE (exp)))
2149 warning ("%Hstatement with no effect", &emit_locus);
2152 /* If EXP is of function type and we are expanding statements for
2153 value, convert it to pointer-to-function. */
2154 if (want_value && TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE)
2155 exp = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (exp)), exp);
2157 /* The call to `expand_expr' could cause last_expr_type and
2158 last_expr_value to get reset. Therefore, we set last_expr_value
2159 and last_expr_type *after* calling expand_expr. */
2160 value = expand_expr (exp, want_value ? NULL_RTX : const0_rtx,
2162 type = TREE_TYPE (exp);
2164 /* If all we do is reference a volatile value in memory,
2165 copy it to a register to be sure it is actually touched. */
2166 if (value && GET_CODE (value) == MEM && TREE_THIS_VOLATILE (exp))
2168 if (TYPE_MODE (type) == VOIDmode)
2170 else if (TYPE_MODE (type) != BLKmode)
2171 value = copy_to_reg (value);
2174 rtx lab = gen_label_rtx ();
2176 /* Compare the value with itself to reference it. */
2177 emit_cmp_and_jump_insns (value, value, EQ,
2178 expand_expr (TYPE_SIZE (type),
2179 NULL_RTX, VOIDmode, 0),
2185 /* If this expression is part of a ({...}) and is in memory, we may have
2186 to preserve temporaries. */
2187 preserve_temp_slots (value);
2189 /* Free any temporaries used to evaluate this expression. Any temporary
2190 used as a result of this expression will already have been preserved
2196 last_expr_value = value;
2197 last_expr_type = type;
2203 /* Warn if EXP contains any computations whose results are not used.
2204 Return 1 if a warning is printed; 0 otherwise. */
2207 warn_if_unused_value (tree exp)
2209 if (TREE_USED (exp))
2212 /* Don't warn about void constructs. This includes casting to void,
2213 void function calls, and statement expressions with a final cast
2215 if (VOID_TYPE_P (TREE_TYPE (exp)))
2218 switch (TREE_CODE (exp))
2220 case PREINCREMENT_EXPR:
2221 case POSTINCREMENT_EXPR:
2222 case PREDECREMENT_EXPR:
2223 case POSTDECREMENT_EXPR:
2229 case TRY_CATCH_EXPR:
2230 case WITH_CLEANUP_EXPR:
2235 /* For a binding, warn if no side effect within it. */
2236 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2239 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2241 case TRUTH_ORIF_EXPR:
2242 case TRUTH_ANDIF_EXPR:
2243 /* In && or ||, warn if 2nd operand has no side effect. */
2244 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2247 if (TREE_NO_UNUSED_WARNING (exp))
2249 if (warn_if_unused_value (TREE_OPERAND (exp, 0)))
2251 /* Let people do `(foo (), 0)' without a warning. */
2252 if (TREE_CONSTANT (TREE_OPERAND (exp, 1)))
2254 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2258 case NON_LVALUE_EXPR:
2259 /* Don't warn about conversions not explicit in the user's program. */
2260 if (TREE_NO_UNUSED_WARNING (exp))
2262 /* Assignment to a cast usually results in a cast of a modify.
2263 Don't complain about that. There can be an arbitrary number of
2264 casts before the modify, so we must loop until we find the first
2265 non-cast expression and then test to see if that is a modify. */
2267 tree tem = TREE_OPERAND (exp, 0);
2269 while (TREE_CODE (tem) == CONVERT_EXPR || TREE_CODE (tem) == NOP_EXPR)
2270 tem = TREE_OPERAND (tem, 0);
2272 if (TREE_CODE (tem) == MODIFY_EXPR || TREE_CODE (tem) == INIT_EXPR
2273 || TREE_CODE (tem) == CALL_EXPR)
2279 /* Don't warn about automatic dereferencing of references, since
2280 the user cannot control it. */
2281 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (exp, 0))) == REFERENCE_TYPE)
2282 return warn_if_unused_value (TREE_OPERAND (exp, 0));
2286 /* Referencing a volatile value is a side effect, so don't warn. */
2288 || TREE_CODE_CLASS (TREE_CODE (exp)) == 'r')
2289 && TREE_THIS_VOLATILE (exp))
2292 /* If this is an expression which has no operands, there is no value
2293 to be unused. There are no such language-independent codes,
2294 but front ends may define such. */
2295 if (TREE_CODE_CLASS (TREE_CODE (exp)) == 'e'
2296 && TREE_CODE_LENGTH (TREE_CODE (exp)) == 0)
2300 /* If this is an expression with side effects, don't warn. */
2301 if (TREE_SIDE_EFFECTS (exp))
2304 warning ("%Hvalue computed is not used", &emit_locus);
2309 /* Clear out the memory of the last expression evaluated. */
2312 clear_last_expr (void)
2314 last_expr_type = NULL_TREE;
2315 last_expr_value = NULL_RTX;
2318 /* Begin a statement-expression, i.e., a series of statements which
2319 may return a value. Return the RTL_EXPR for this statement expr.
2320 The caller must save that value and pass it to
2321 expand_end_stmt_expr. If HAS_SCOPE is nonzero, temporaries created
2322 in the statement-expression are deallocated at the end of the
2326 expand_start_stmt_expr (int has_scope)
2330 /* Make the RTL_EXPR node temporary, not momentary,
2331 so that rtl_expr_chain doesn't become garbage. */
2332 t = make_node (RTL_EXPR);
2333 do_pending_stack_adjust ();
2335 start_sequence_for_rtl_expr (t);
2339 expr_stmts_for_value++;
2343 /* Restore the previous state at the end of a statement that returns a value.
2344 Returns a tree node representing the statement's value and the
2345 insns to compute the value.
2347 The nodes of that expression have been freed by now, so we cannot use them.
2348 But we don't want to do that anyway; the expression has already been
2349 evaluated and now we just want to use the value. So generate a RTL_EXPR
2350 with the proper type and RTL value.
2352 If the last substatement was not an expression,
2353 return something with type `void'. */
2356 expand_end_stmt_expr (tree t)
2360 if (! last_expr_value || ! last_expr_type)
2362 last_expr_value = const0_rtx;
2363 last_expr_type = void_type_node;
2365 else if (GET_CODE (last_expr_value) != REG && ! CONSTANT_P (last_expr_value))
2366 /* Remove any possible QUEUED. */
2367 last_expr_value = protect_from_queue (last_expr_value, 0);
2371 TREE_TYPE (t) = last_expr_type;
2372 RTL_EXPR_RTL (t) = last_expr_value;
2373 RTL_EXPR_SEQUENCE (t) = get_insns ();
2375 rtl_expr_chain = tree_cons (NULL_TREE, t, rtl_expr_chain);
2379 /* Don't consider deleting this expr or containing exprs at tree level. */
2380 TREE_SIDE_EFFECTS (t) = 1;
2381 /* Propagate volatility of the actual RTL expr. */
2382 TREE_THIS_VOLATILE (t) = volatile_refs_p (last_expr_value);
2385 expr_stmts_for_value--;
2390 /* Generate RTL for the start of an if-then. COND is the expression
2391 whose truth should be tested.
2393 If EXITFLAG is nonzero, this conditional is visible to
2394 `exit_something'. */
2397 expand_start_cond (tree cond, int exitflag)
2399 struct nesting *thiscond = ALLOC_NESTING ();
2401 /* Make an entry on cond_stack for the cond we are entering. */
2403 thiscond->desc = COND_NESTING;
2404 thiscond->next = cond_stack;
2405 thiscond->all = nesting_stack;
2406 thiscond->depth = ++nesting_depth;
2407 thiscond->data.cond.next_label = gen_label_rtx ();
2408 /* Before we encounter an `else', we don't need a separate exit label
2409 unless there are supposed to be exit statements
2410 to exit this conditional. */
2411 thiscond->exit_label = exitflag ? gen_label_rtx () : 0;
2412 thiscond->data.cond.endif_label = thiscond->exit_label;
2413 cond_stack = thiscond;
2414 nesting_stack = thiscond;
2416 do_jump (cond, thiscond->data.cond.next_label, NULL_RTX);
2419 /* Generate RTL between then-clause and the elseif-clause
2420 of an if-then-elseif-.... */
2423 expand_start_elseif (tree cond)
2425 if (cond_stack->data.cond.endif_label == 0)
2426 cond_stack->data.cond.endif_label = gen_label_rtx ();
2427 emit_jump (cond_stack->data.cond.endif_label);
2428 emit_label (cond_stack->data.cond.next_label);
2429 cond_stack->data.cond.next_label = gen_label_rtx ();
2430 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
2433 /* Generate RTL between the then-clause and the else-clause
2434 of an if-then-else. */
2437 expand_start_else (void)
2439 if (cond_stack->data.cond.endif_label == 0)
2440 cond_stack->data.cond.endif_label = gen_label_rtx ();
2442 emit_jump (cond_stack->data.cond.endif_label);
2443 emit_label (cond_stack->data.cond.next_label);
2444 cond_stack->data.cond.next_label = 0; /* No more _else or _elseif calls. */
2447 /* After calling expand_start_else, turn this "else" into an "else if"
2448 by providing another condition. */
2451 expand_elseif (tree cond)
2453 cond_stack->data.cond.next_label = gen_label_rtx ();
2454 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
2457 /* Generate RTL for the end of an if-then.
2458 Pop the record for it off of cond_stack. */
2461 expand_end_cond (void)
2463 struct nesting *thiscond = cond_stack;
2465 do_pending_stack_adjust ();
2466 if (thiscond->data.cond.next_label)
2467 emit_label (thiscond->data.cond.next_label);
2468 if (thiscond->data.cond.endif_label)
2469 emit_label (thiscond->data.cond.endif_label);
2471 POPSTACK (cond_stack);
2475 /* Generate RTL for the start of a loop. EXIT_FLAG is nonzero if this
2476 loop should be exited by `exit_something'. This is a loop for which
2477 `expand_continue' will jump to the top of the loop.
2479 Make an entry on loop_stack to record the labels associated with
2483 expand_start_loop (int exit_flag)
2485 struct nesting *thisloop = ALLOC_NESTING ();
2487 /* Make an entry on loop_stack for the loop we are entering. */
2489 thisloop->desc = LOOP_NESTING;
2490 thisloop->next = loop_stack;
2491 thisloop->all = nesting_stack;
2492 thisloop->depth = ++nesting_depth;
2493 thisloop->data.loop.start_label = gen_label_rtx ();
2494 thisloop->data.loop.end_label = gen_label_rtx ();
2495 thisloop->data.loop.continue_label = thisloop->data.loop.start_label;
2496 thisloop->exit_label = exit_flag ? thisloop->data.loop.end_label : 0;
2497 loop_stack = thisloop;
2498 nesting_stack = thisloop;
2500 do_pending_stack_adjust ();
2502 emit_note (NOTE_INSN_LOOP_BEG);
2503 emit_label (thisloop->data.loop.start_label);
2508 /* Like expand_start_loop but for a loop where the continuation point
2509 (for expand_continue_loop) will be specified explicitly. */
2512 expand_start_loop_continue_elsewhere (int exit_flag)
2514 struct nesting *thisloop = expand_start_loop (exit_flag);
2515 loop_stack->data.loop.continue_label = gen_label_rtx ();
2519 /* Begin a null, aka do { } while (0) "loop". But since the contents
2520 of said loop can still contain a break, we must frob the loop nest. */
2523 expand_start_null_loop (void)
2525 struct nesting *thisloop = ALLOC_NESTING ();
2527 /* Make an entry on loop_stack for the loop we are entering. */
2529 thisloop->desc = LOOP_NESTING;
2530 thisloop->next = loop_stack;
2531 thisloop->all = nesting_stack;
2532 thisloop->depth = ++nesting_depth;
2533 thisloop->data.loop.start_label = emit_note (NOTE_INSN_DELETED);
2534 thisloop->data.loop.end_label = gen_label_rtx ();
2535 thisloop->data.loop.continue_label = thisloop->data.loop.end_label;
2536 thisloop->exit_label = thisloop->data.loop.end_label;
2537 loop_stack = thisloop;
2538 nesting_stack = thisloop;
2543 /* Specify the continuation point for a loop started with
2544 expand_start_loop_continue_elsewhere.
2545 Use this at the point in the code to which a continue statement
2549 expand_loop_continue_here (void)
2551 do_pending_stack_adjust ();
2552 emit_note (NOTE_INSN_LOOP_CONT);
2553 emit_label (loop_stack->data.loop.continue_label);
2556 /* Finish a loop. Generate a jump back to the top and the loop-exit label.
2557 Pop the block off of loop_stack. */
2560 expand_end_loop (void)
2562 rtx start_label = loop_stack->data.loop.start_label;
2564 int eh_regions, debug_blocks;
2567 /* Mark the continue-point at the top of the loop if none elsewhere. */
2568 if (start_label == loop_stack->data.loop.continue_label)
2569 emit_note_before (NOTE_INSN_LOOP_CONT, start_label);
2571 do_pending_stack_adjust ();
2573 /* If the loop starts with a loop exit, roll that to the end where
2574 it will optimize together with the jump back.
2576 If the loop presently looks like this (in pseudo-C):
2580 if (test) goto end_label;
2586 transform it to look like:
2593 if (test) goto end_label;
2597 We rely on the presence of NOTE_INSN_LOOP_END_TOP_COND to mark
2598 the end of the entry conditional. Without this, our lexical scan
2599 can't tell the difference between an entry conditional and a
2600 body conditional that exits the loop. Mistaking the two means
2601 that we can misplace the NOTE_INSN_LOOP_CONT note, which can
2602 screw up loop unrolling.
2604 Things will be oh so much better when loop optimization is done
2605 off of a proper control flow graph... */
2607 /* Scan insns from the top of the loop looking for the END_TOP_COND note. */
2610 eh_regions = debug_blocks = 0;
2611 for (etc_note = start_label; etc_note ; etc_note = NEXT_INSN (etc_note))
2612 if (GET_CODE (etc_note) == NOTE)
2614 if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_LOOP_END_TOP_COND)
2617 /* We must not walk into a nested loop. */
2618 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_LOOP_BEG)
2620 etc_note = NULL_RTX;
2624 /* At the same time, scan for EH region notes, as we don't want
2625 to scrog region nesting. This shouldn't happen, but... */
2626 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_EH_REGION_BEG)
2628 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_EH_REGION_END)
2630 if (--eh_regions < 0)
2631 /* We've come to the end of an EH region, but never saw the
2632 beginning of that region. That means that an EH region
2633 begins before the top of the loop, and ends in the middle
2634 of it. The existence of such a situation violates a basic
2635 assumption in this code, since that would imply that even
2636 when EH_REGIONS is zero, we might move code out of an
2637 exception region. */
2641 /* Likewise for debug scopes. In this case we'll either (1) move
2642 all of the notes if they are properly nested or (2) leave the
2643 notes alone and only rotate the loop at high optimization
2644 levels when we expect to scrog debug info. */
2645 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_BLOCK_BEG)
2647 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_BLOCK_END)
2650 else if (INSN_P (etc_note))
2657 && (debug_blocks == 0 || optimize >= 2)
2658 && NEXT_INSN (etc_note) != NULL_RTX
2659 && ! any_condjump_p (get_last_insn ()))
2661 /* We found one. Move everything from START to ETC to the end
2662 of the loop, and add a jump from the top of the loop. */
2663 rtx top_label = gen_label_rtx ();
2664 rtx start_move = start_label;
2666 /* If the start label is preceded by a NOTE_INSN_LOOP_CONT note,
2667 then we want to move this note also. */
2668 if (GET_CODE (PREV_INSN (start_move)) == NOTE
2669 && NOTE_LINE_NUMBER (PREV_INSN (start_move)) == NOTE_INSN_LOOP_CONT)
2670 start_move = PREV_INSN (start_move);
2672 emit_label_before (top_label, start_move);
2674 /* Actually move the insns. If the debug scopes are nested, we
2675 can move everything at once. Otherwise we have to move them
2676 one by one and squeeze out the block notes. */
2677 if (debug_blocks == 0)
2678 reorder_insns (start_move, etc_note, get_last_insn ());
2681 rtx insn, next_insn;
2682 for (insn = start_move; insn; insn = next_insn)
2684 /* Figure out which insn comes after this one. We have
2685 to do this before we move INSN. */
2686 next_insn = (insn == etc_note ? NULL : NEXT_INSN (insn));
2688 if (GET_CODE (insn) == NOTE
2689 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
2690 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
2693 reorder_insns (insn, insn, get_last_insn ());
2697 /* Add the jump from the top of the loop. */
2698 emit_jump_insn_before (gen_jump (start_label), top_label);
2699 emit_barrier_before (top_label);
2700 start_label = top_label;
2703 emit_jump (start_label);
2704 emit_note (NOTE_INSN_LOOP_END);
2705 emit_label (loop_stack->data.loop.end_label);
2707 POPSTACK (loop_stack);
2712 /* Finish a null loop, aka do { } while (0). */
2715 expand_end_null_loop (void)
2717 do_pending_stack_adjust ();
2718 emit_label (loop_stack->data.loop.end_label);
2720 POPSTACK (loop_stack);
2725 /* Generate a jump to the current loop's continue-point.
2726 This is usually the top of the loop, but may be specified
2727 explicitly elsewhere. If not currently inside a loop,
2728 return 0 and do nothing; caller will print an error message. */
2731 expand_continue_loop (struct nesting *whichloop)
2733 /* Emit information for branch prediction. */
2736 if (flag_guess_branch_prob)
2738 note = emit_note (NOTE_INSN_PREDICTION);
2739 NOTE_PREDICTION (note) = NOTE_PREDICT (PRED_CONTINUE, IS_TAKEN);
2743 whichloop = loop_stack;
2746 expand_goto_internal (NULL_TREE, whichloop->data.loop.continue_label,
2751 /* Generate a jump to exit the current loop. If not currently inside a loop,
2752 return 0 and do nothing; caller will print an error message. */
2755 expand_exit_loop (struct nesting *whichloop)
2759 whichloop = loop_stack;
2762 expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label, NULL_RTX);
2766 /* Generate a conditional jump to exit the current loop if COND
2767 evaluates to zero. If not currently inside a loop,
2768 return 0 and do nothing; caller will print an error message. */
2771 expand_exit_loop_if_false (struct nesting *whichloop, tree cond)
2777 whichloop = loop_stack;
2781 if (integer_nonzerop (cond))
2783 if (integer_zerop (cond))
2784 return expand_exit_loop (whichloop);
2786 /* Check if we definitely won't need a fixup. */
2787 if (whichloop == nesting_stack)
2789 jumpifnot (cond, whichloop->data.loop.end_label);
2793 /* In order to handle fixups, we actually create a conditional jump
2794 around an unconditional branch to exit the loop. If fixups are
2795 necessary, they go before the unconditional branch. */
2797 label = gen_label_rtx ();
2798 jumpif (cond, label);
2799 expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label,
2806 /* Like expand_exit_loop_if_false except also emit a note marking
2807 the end of the conditional. Should only be used immediately
2808 after expand_loop_start. */
2811 expand_exit_loop_top_cond (struct nesting *whichloop, tree cond)
2813 if (! expand_exit_loop_if_false (whichloop, cond))
2816 emit_note (NOTE_INSN_LOOP_END_TOP_COND);
2820 /* Return nonzero if we should preserve sub-expressions as separate
2821 pseudos. We never do so if we aren't optimizing. We always do so
2822 if -fexpensive-optimizations.
2824 Otherwise, we only do so if we are in the "early" part of a loop. I.e.,
2825 the loop may still be a small one. */
2828 preserve_subexpressions_p (void)
2832 if (flag_expensive_optimizations)
2835 if (optimize == 0 || cfun == 0 || cfun->stmt == 0 || loop_stack == 0)
2838 insn = get_last_insn_anywhere ();
2841 && (INSN_UID (insn) - INSN_UID (loop_stack->data.loop.start_label)
2842 < n_non_fixed_regs * 3));
2846 /* Generate a jump to exit the current loop, conditional, binding contour
2847 or case statement. Not all such constructs are visible to this function,
2848 only those started with EXIT_FLAG nonzero. Individual languages use
2849 the EXIT_FLAG parameter to control which kinds of constructs you can
2852 If not currently inside anything that can be exited,
2853 return 0 and do nothing; caller will print an error message. */
2856 expand_exit_something (void)
2860 for (n = nesting_stack; n; n = n->all)
2861 if (n->exit_label != 0)
2863 expand_goto_internal (NULL_TREE, n->exit_label, NULL_RTX);
2870 /* Generate RTL to return from the current function, with no value.
2871 (That is, we do not do anything about returning any value.) */
2874 expand_null_return (void)
2878 last_insn = get_last_insn ();
2880 /* If this function was declared to return a value, but we
2881 didn't, clobber the return registers so that they are not
2882 propagated live to the rest of the function. */
2883 clobber_return_register ();
2885 expand_null_return_1 (last_insn);
2888 /* Try to guess whether the value of return means error code. */
2889 static enum br_predictor
2890 return_prediction (rtx val)
2892 /* Different heuristics for pointers and scalars. */
2893 if (POINTER_TYPE_P (TREE_TYPE (DECL_RESULT (current_function_decl))))
2895 /* NULL is usually not returned. */
2896 if (val == const0_rtx)
2897 return PRED_NULL_RETURN;
2901 /* Negative return values are often used to indicate
2903 if (GET_CODE (val) == CONST_INT
2904 && INTVAL (val) < 0)
2905 return PRED_NEGATIVE_RETURN;
2906 /* Constant return values are also usually erors,
2907 zero/one often mean booleans so exclude them from the
2909 if (CONSTANT_P (val)
2910 && (val != const0_rtx && val != const1_rtx))
2911 return PRED_CONST_RETURN;
2913 return PRED_NO_PREDICTION;
2917 /* If the current function returns values in the most significant part
2918 of a register, shift return value VAL appropriately. The mode of
2919 the function's return type is known not to be BLKmode. */
2922 shift_return_value (rtx val)
2926 type = TREE_TYPE (DECL_RESULT (current_function_decl));
2927 if (targetm.calls.return_in_msb (type))
2930 HOST_WIDE_INT shift;
2932 target = DECL_RTL (DECL_RESULT (current_function_decl));
2933 shift = (GET_MODE_BITSIZE (GET_MODE (target))
2934 - BITS_PER_UNIT * int_size_in_bytes (type));
2936 val = expand_binop (GET_MODE (target), ashl_optab,
2937 gen_lowpart (GET_MODE (target), val),
2938 GEN_INT (shift), target, 1, OPTAB_WIDEN);
2944 /* Generate RTL to return from the current function, with value VAL. */
2947 expand_value_return (rtx val)
2951 enum br_predictor pred;
2953 if (flag_guess_branch_prob
2954 && (pred = return_prediction (val)) != PRED_NO_PREDICTION)
2956 /* Emit information for branch prediction. */
2959 note = emit_note (NOTE_INSN_PREDICTION);
2961 NOTE_PREDICTION (note) = NOTE_PREDICT (pred, NOT_TAKEN);
2965 last_insn = get_last_insn ();
2966 return_reg = DECL_RTL (DECL_RESULT (current_function_decl));
2968 /* Copy the value to the return location
2969 unless it's already there. */
2971 if (return_reg != val)
2973 tree type = TREE_TYPE (DECL_RESULT (current_function_decl));
2974 if (targetm.calls.promote_function_return (TREE_TYPE (current_function_decl)))
2976 int unsignedp = TREE_UNSIGNED (type);
2977 enum machine_mode old_mode
2978 = DECL_MODE (DECL_RESULT (current_function_decl));
2979 enum machine_mode mode
2980 = promote_mode (type, old_mode, &unsignedp, 1);
2982 if (mode != old_mode)
2983 val = convert_modes (mode, old_mode, val, unsignedp);
2985 if (GET_CODE (return_reg) == PARALLEL)
2986 emit_group_load (return_reg, val, type, int_size_in_bytes (type));
2988 emit_move_insn (return_reg, val);
2991 expand_null_return_1 (last_insn);
2994 /* Output a return with no value. If LAST_INSN is nonzero,
2995 pretend that the return takes place after LAST_INSN. */
2998 expand_null_return_1 (rtx last_insn)
3000 rtx end_label = cleanup_label ? cleanup_label : return_label;
3002 clear_pending_stack_adjust ();
3003 do_pending_stack_adjust ();
3007 end_label = return_label = gen_label_rtx ();
3008 expand_goto_internal (NULL_TREE, end_label, last_insn);
3011 /* Generate RTL to evaluate the expression RETVAL and return it
3012 from the current function. */
3015 expand_return (tree retval)
3017 /* If there are any cleanups to be performed, then they will
3018 be inserted following LAST_INSN. It is desirable
3019 that the last_insn, for such purposes, should be the
3020 last insn before computing the return value. Otherwise, cleanups
3021 which call functions can clobber the return value. */
3022 /* ??? rms: I think that is erroneous, because in C++ it would
3023 run destructors on variables that might be used in the subsequent
3024 computation of the return value. */
3030 /* If function wants no value, give it none. */
3031 if (TREE_CODE (TREE_TYPE (TREE_TYPE (current_function_decl))) == VOID_TYPE)
3033 expand_expr (retval, NULL_RTX, VOIDmode, 0);
3035 expand_null_return ();
3039 if (retval == error_mark_node)
3041 /* Treat this like a return of no value from a function that
3043 expand_null_return ();
3046 else if (TREE_CODE (retval) == RESULT_DECL)
3047 retval_rhs = retval;
3048 else if ((TREE_CODE (retval) == MODIFY_EXPR || TREE_CODE (retval) == INIT_EXPR)
3049 && TREE_CODE (TREE_OPERAND (retval, 0)) == RESULT_DECL)
3050 retval_rhs = TREE_OPERAND (retval, 1);
3051 else if (VOID_TYPE_P (TREE_TYPE (retval)))
3052 /* Recognize tail-recursive call to void function. */
3053 retval_rhs = retval;
3055 retval_rhs = NULL_TREE;
3057 last_insn = get_last_insn ();
3059 /* Distribute return down conditional expr if either of the sides
3060 may involve tail recursion (see test below). This enhances the number
3061 of tail recursions we see. Don't do this always since it can produce
3062 sub-optimal code in some cases and we distribute assignments into
3063 conditional expressions when it would help. */
3065 if (optimize && retval_rhs != 0
3066 && frame_offset == 0
3067 && TREE_CODE (retval_rhs) == COND_EXPR
3068 && (TREE_CODE (TREE_OPERAND (retval_rhs, 1)) == CALL_EXPR
3069 || TREE_CODE (TREE_OPERAND (retval_rhs, 2)) == CALL_EXPR))
3071 rtx label = gen_label_rtx ();
3074 do_jump (TREE_OPERAND (retval_rhs, 0), label, NULL_RTX);
3075 start_cleanup_deferral ();
3076 expr = build (MODIFY_EXPR, TREE_TYPE (TREE_TYPE (current_function_decl)),
3077 DECL_RESULT (current_function_decl),
3078 TREE_OPERAND (retval_rhs, 1));
3079 TREE_SIDE_EFFECTS (expr) = 1;
3080 expand_return (expr);
3083 expr = build (MODIFY_EXPR, TREE_TYPE (TREE_TYPE (current_function_decl)),
3084 DECL_RESULT (current_function_decl),
3085 TREE_OPERAND (retval_rhs, 2));
3086 TREE_SIDE_EFFECTS (expr) = 1;
3087 expand_return (expr);
3088 end_cleanup_deferral ();
3092 result_rtl = DECL_RTL (DECL_RESULT (current_function_decl));
3094 /* If the result is an aggregate that is being returned in one (or more)
3095 registers, load the registers here. The compiler currently can't handle
3096 copying a BLKmode value into registers. We could put this code in a
3097 more general area (for use by everyone instead of just function
3098 call/return), but until this feature is generally usable it is kept here
3099 (and in expand_call). The value must go into a pseudo in case there
3100 are cleanups that will clobber the real return register. */
3103 && TYPE_MODE (TREE_TYPE (retval_rhs)) == BLKmode
3104 && GET_CODE (result_rtl) == REG)
3107 unsigned HOST_WIDE_INT bitpos, xbitpos;
3108 unsigned HOST_WIDE_INT padding_correction = 0;
3109 unsigned HOST_WIDE_INT bytes
3110 = int_size_in_bytes (TREE_TYPE (retval_rhs));
3111 int n_regs = (bytes + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
3112 unsigned int bitsize
3113 = MIN (TYPE_ALIGN (TREE_TYPE (retval_rhs)), BITS_PER_WORD);
3114 rtx *result_pseudos = alloca (sizeof (rtx) * n_regs);
3115 rtx result_reg, src = NULL_RTX, dst = NULL_RTX;
3116 rtx result_val = expand_expr (retval_rhs, NULL_RTX, VOIDmode, 0);
3117 enum machine_mode tmpmode, result_reg_mode;
3121 expand_null_return ();
3125 /* If the structure doesn't take up a whole number of words, see
3126 whether the register value should be padded on the left or on
3127 the right. Set PADDING_CORRECTION to the number of padding
3128 bits needed on the left side.
3130 In most ABIs, the structure will be returned at the least end of
3131 the register, which translates to right padding on little-endian
3132 targets and left padding on big-endian targets. The opposite
3133 holds if the structure is returned at the most significant
3134 end of the register. */
3135 if (bytes % UNITS_PER_WORD != 0
3136 && (targetm.calls.return_in_msb (TREE_TYPE (retval_rhs))
3138 : BYTES_BIG_ENDIAN))
3139 padding_correction = (BITS_PER_WORD - ((bytes % UNITS_PER_WORD)
3142 /* Copy the structure BITSIZE bits at a time. */
3143 for (bitpos = 0, xbitpos = padding_correction;
3144 bitpos < bytes * BITS_PER_UNIT;
3145 bitpos += bitsize, xbitpos += bitsize)
3147 /* We need a new destination pseudo each time xbitpos is
3148 on a word boundary and when xbitpos == padding_correction
3149 (the first time through). */
3150 if (xbitpos % BITS_PER_WORD == 0
3151 || xbitpos == padding_correction)
3153 /* Generate an appropriate register. */
3154 dst = gen_reg_rtx (word_mode);
3155 result_pseudos[xbitpos / BITS_PER_WORD] = dst;
3157 /* Clear the destination before we move anything into it. */
3158 emit_move_insn (dst, CONST0_RTX (GET_MODE (dst)));
3161 /* We need a new source operand each time bitpos is on a word
3163 if (bitpos % BITS_PER_WORD == 0)
3164 src = operand_subword_force (result_val,
3165 bitpos / BITS_PER_WORD,
3168 /* Use bitpos for the source extraction (left justified) and
3169 xbitpos for the destination store (right justified). */
3170 store_bit_field (dst, bitsize, xbitpos % BITS_PER_WORD, word_mode,
3171 extract_bit_field (src, bitsize,
3172 bitpos % BITS_PER_WORD, 1,
3173 NULL_RTX, word_mode, word_mode,
3178 tmpmode = GET_MODE (result_rtl);
3179 if (tmpmode == BLKmode)
3181 /* Find the smallest integer mode large enough to hold the
3182 entire structure and use that mode instead of BLKmode
3183 on the USE insn for the return register. */
3184 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
3185 tmpmode != VOIDmode;
3186 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
3187 /* Have we found a large enough mode? */
3188 if (GET_MODE_SIZE (tmpmode) >= bytes)
3191 /* No suitable mode found. */
3192 if (tmpmode == VOIDmode)
3195 PUT_MODE (result_rtl, tmpmode);
3198 if (GET_MODE_SIZE (tmpmode) < GET_MODE_SIZE (word_mode))
3199 result_reg_mode = word_mode;
3201 result_reg_mode = tmpmode;
3202 result_reg = gen_reg_rtx (result_reg_mode);
3205 for (i = 0; i < n_regs; i++)
3206 emit_move_insn (operand_subword (result_reg, i, 0, result_reg_mode),
3209 if (tmpmode != result_reg_mode)
3210 result_reg = gen_lowpart (tmpmode, result_reg);
3212 expand_value_return (result_reg);
3214 else if (retval_rhs != 0
3215 && !VOID_TYPE_P (TREE_TYPE (retval_rhs))
3216 && (GET_CODE (result_rtl) == REG
3217 || (GET_CODE (result_rtl) == PARALLEL)))
3219 /* Calculate the return value into a temporary (usually a pseudo
3221 tree ot = TREE_TYPE (DECL_RESULT (current_function_decl));
3222 tree nt = build_qualified_type (ot, TYPE_QUALS (ot) | TYPE_QUAL_CONST);
3224 val = assign_temp (nt, 0, 0, 1);
3225 val = expand_expr (retval_rhs, val, GET_MODE (val), 0);
3226 val = force_not_mem (val);
3228 /* Return the calculated value, doing cleanups first. */
3229 expand_value_return (shift_return_value (val));
3233 /* No cleanups or no hard reg used;
3234 calculate value into hard return reg. */
3235 expand_expr (retval, const0_rtx, VOIDmode, 0);
3237 expand_value_return (result_rtl);
3241 /* Attempt to optimize a potential tail recursion call into a goto.
3242 ARGUMENTS are the arguments to a CALL_EXPR; LAST_INSN indicates
3243 where to place the jump to the tail recursion label.
3245 Return TRUE if the call was optimized into a goto. */
3248 optimize_tail_recursion (tree arguments, rtx last_insn)
3250 /* Finish checking validity, and if valid emit code to set the
3251 argument variables for the new call. */
3252 if (tail_recursion_args (arguments, DECL_ARGUMENTS (current_function_decl)))
3254 if (tail_recursion_label == 0)
3256 tail_recursion_label = gen_label_rtx ();
3257 emit_label_after (tail_recursion_label,
3258 tail_recursion_reentry);
3261 expand_goto_internal (NULL_TREE, tail_recursion_label, last_insn);
3268 /* Emit code to alter this function's formal parms for a tail-recursive call.
3269 ACTUALS is a list of actual parameter expressions (chain of TREE_LISTs).
3270 FORMALS is the chain of decls of formals.
3271 Return 1 if this can be done;
3272 otherwise return 0 and do not emit any code. */
3275 tail_recursion_args (tree actuals, tree formals)
3277 tree a = actuals, f = formals;
3281 /* Check that number and types of actuals are compatible
3282 with the formals. This is not always true in valid C code.
3283 Also check that no formal needs to be addressable
3284 and that all formals are scalars. */
3286 /* Also count the args. */
3288 for (a = actuals, f = formals, i = 0; a && f; a = TREE_CHAIN (a), f = TREE_CHAIN (f), i++)
3290 if (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_VALUE (a)))
3291 != TYPE_MAIN_VARIANT (TREE_TYPE (f)))
3293 if (GET_CODE (DECL_RTL (f)) != REG || DECL_MODE (f) == BLKmode)
3296 if (a != 0 || f != 0)
3299 /* Compute all the actuals. */
3301 argvec = alloca (i * sizeof (rtx));
3303 for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
3304 argvec[i] = expand_expr (TREE_VALUE (a), NULL_RTX, VOIDmode, 0);
3306 /* Find which actual values refer to current values of previous formals.
3307 Copy each of them now, before any formal is changed. */
3309 for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
3313 for (f = formals, j = 0; j < i; f = TREE_CHAIN (f), j++)
3314 if (reg_mentioned_p (DECL_RTL (f), argvec[i]))
3320 argvec[i] = copy_to_reg (argvec[i]);
3323 /* Store the values of the actuals into the formals. */
3325 for (f = formals, a = actuals, i = 0; f;
3326 f = TREE_CHAIN (f), a = TREE_CHAIN (a), i++)
3328 if (GET_MODE (DECL_RTL (f)) == GET_MODE (argvec[i]))
3329 emit_move_insn (DECL_RTL (f), argvec[i]);
3332 rtx tmp = argvec[i];
3333 int unsignedp = TREE_UNSIGNED (TREE_TYPE (TREE_VALUE (a)));
3334 promote_mode(TREE_TYPE (TREE_VALUE (a)), GET_MODE (tmp),
3336 if (DECL_MODE (f) != GET_MODE (DECL_RTL (f)))
3338 tmp = gen_reg_rtx (DECL_MODE (f));
3339 convert_move (tmp, argvec[i], unsignedp);
3341 convert_move (DECL_RTL (f), tmp, unsignedp);
3349 /* Generate the RTL code for entering a binding contour.
3350 The variables are declared one by one, by calls to `expand_decl'.
3352 FLAGS is a bitwise or of the following flags:
3354 1 - Nonzero if this construct should be visible to
3357 2 - Nonzero if this contour does not require a
3358 NOTE_INSN_BLOCK_BEG note. Virtually all calls from
3359 language-independent code should set this flag because they
3360 will not create corresponding BLOCK nodes. (There should be
3361 a one-to-one correspondence between NOTE_INSN_BLOCK_BEG notes
3362 and BLOCKs.) If this flag is set, MARK_ENDS should be zero
3363 when expand_end_bindings is called.
3365 If we are creating a NOTE_INSN_BLOCK_BEG note, a BLOCK may
3366 optionally be supplied. If so, it becomes the NOTE_BLOCK for the
3370 expand_start_bindings_and_block (int flags, tree block)
3372 struct nesting *thisblock = ALLOC_NESTING ();
3374 int exit_flag = ((flags & 1) != 0);
3375 int block_flag = ((flags & 2) == 0);
3377 /* If a BLOCK is supplied, then the caller should be requesting a
3378 NOTE_INSN_BLOCK_BEG note. */
3379 if (!block_flag && block)
3382 /* Create a note to mark the beginning of the block. */
3385 note = emit_note (NOTE_INSN_BLOCK_BEG);
3386 NOTE_BLOCK (note) = block;
3389 note = emit_note (NOTE_INSN_DELETED);
3391 /* Make an entry on block_stack for the block we are entering. */
3393 thisblock->desc = BLOCK_NESTING;
3394 thisblock->next = block_stack;
3395 thisblock->all = nesting_stack;
3396 thisblock->depth = ++nesting_depth;
3397 thisblock->data.block.stack_level = 0;
3398 thisblock->data.block.cleanups = 0;
3399 thisblock->data.block.exception_region = 0;
3400 thisblock->data.block.block_target_temp_slot_level = target_temp_slot_level;
3402 thisblock->data.block.conditional_code = 0;
3403 thisblock->data.block.last_unconditional_cleanup = note;
3404 /* When we insert instructions after the last unconditional cleanup,
3405 we don't adjust last_insn. That means that a later add_insn will
3406 clobber the instructions we've just added. The easiest way to
3407 fix this is to just insert another instruction here, so that the
3408 instructions inserted after the last unconditional cleanup are
3409 never the last instruction. */
3410 emit_note (NOTE_INSN_DELETED);
3413 && !(block_stack->data.block.cleanups == NULL_TREE
3414 && block_stack->data.block.outer_cleanups == NULL_TREE))
3415 thisblock->data.block.outer_cleanups
3416 = tree_cons (NULL_TREE, block_stack->data.block.cleanups,
3417 block_stack->data.block.outer_cleanups);
3419 thisblock->data.block.outer_cleanups = 0;
3420 thisblock->data.block.label_chain = 0;
3421 thisblock->data.block.innermost_stack_block = stack_block_stack;
3422 thisblock->data.block.first_insn = note;
3423 thisblock->data.block.block_start_count = ++current_block_start_count;
3424 thisblock->exit_label = exit_flag ? gen_label_rtx () : 0;
3425 block_stack = thisblock;
3426 nesting_stack = thisblock;
3428 /* Make a new level for allocating stack slots. */
3432 /* Specify the scope of temporaries created by TARGET_EXPRs. Similar
3433 to CLEANUP_POINT_EXPR, but handles cases when a series of calls to
3434 expand_expr are made. After we end the region, we know that all
3435 space for all temporaries that were created by TARGET_EXPRs will be
3436 destroyed and their space freed for reuse. */
3439 expand_start_target_temps (void)
3441 /* This is so that even if the result is preserved, the space
3442 allocated will be freed, as we know that it is no longer in use. */
3445 /* Start a new binding layer that will keep track of all cleanup
3446 actions to be performed. */
3447 expand_start_bindings (2);
3449 target_temp_slot_level = temp_slot_level;
3453 expand_end_target_temps (void)
3455 expand_end_bindings (NULL_TREE, 0, 0);
3457 /* This is so that even if the result is preserved, the space
3458 allocated will be freed, as we know that it is no longer in use. */
3462 /* Given a pointer to a BLOCK node return nonzero if (and only if) the node
3463 in question represents the outermost pair of curly braces (i.e. the "body
3464 block") of a function or method.
3466 For any BLOCK node representing a "body block" of a function or method, the
3467 BLOCK_SUPERCONTEXT of the node will point to another BLOCK node which
3468 represents the outermost (function) scope for the function or method (i.e.
3469 the one which includes the formal parameters). The BLOCK_SUPERCONTEXT of
3470 *that* node in turn will point to the relevant FUNCTION_DECL node. */
3473 is_body_block (tree stmt)
3475 if (lang_hooks.no_body_blocks)
3478 if (TREE_CODE (stmt) == BLOCK)
3480 tree parent = BLOCK_SUPERCONTEXT (stmt);
3482 if (parent && TREE_CODE (parent) == BLOCK)
3484 tree grandparent = BLOCK_SUPERCONTEXT (parent);
3486 if (grandparent && TREE_CODE (grandparent) == FUNCTION_DECL)
3494 /* True if we are currently emitting insns in an area of output code
3495 that is controlled by a conditional expression. This is used by
3496 the cleanup handling code to generate conditional cleanup actions. */
3499 conditional_context (void)
3501 return block_stack && block_stack->data.block.conditional_code;
3504 /* Return an opaque pointer to the current nesting level, so frontend code
3505 can check its own sanity. */
3508 current_nesting_level (void)
3510 return cfun ? block_stack : 0;
3513 /* Emit a handler label for a nonlocal goto handler.
3514 Also emit code to store the handler label in SLOT before BEFORE_INSN. */
3517 expand_nl_handler_label (rtx slot, rtx before_insn)
3520 rtx handler_label = gen_label_rtx ();
3522 /* Don't let cleanup_cfg delete the handler. */
3523 LABEL_PRESERVE_P (handler_label) = 1;
3526 emit_move_insn (slot, gen_rtx_LABEL_REF (Pmode, handler_label));
3527 insns = get_insns ();
3529 emit_insn_before (insns, before_insn);
3531 emit_label (handler_label);
3533 return handler_label;
3536 /* Emit code to restore vital registers at the beginning of a nonlocal goto
3539 expand_nl_goto_receiver (void)
3541 #ifdef HAVE_nonlocal_goto
3542 if (! HAVE_nonlocal_goto)
3544 /* First adjust our frame pointer to its actual value. It was
3545 previously set to the start of the virtual area corresponding to
3546 the stacked variables when we branched here and now needs to be
3547 adjusted to the actual hardware fp value.
3549 Assignments are to virtual registers are converted by
3550 instantiate_virtual_regs into the corresponding assignment
3551 to the underlying register (fp in this case) that makes
3552 the original assignment true.
3553 So the following insn will actually be
3554 decrementing fp by STARTING_FRAME_OFFSET. */
3555 emit_move_insn (virtual_stack_vars_rtx, hard_frame_pointer_rtx);
3557 #if ARG_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3558 if (fixed_regs[ARG_POINTER_REGNUM])
3560 #ifdef ELIMINABLE_REGS
3561 /* If the argument pointer can be eliminated in favor of the
3562 frame pointer, we don't need to restore it. We assume here
3563 that if such an elimination is present, it can always be used.
3564 This is the case on all known machines; if we don't make this
3565 assumption, we do unnecessary saving on many machines. */
3566 static const struct elims {const int from, to;} elim_regs[] = ELIMINABLE_REGS;
3569 for (i = 0; i < ARRAY_SIZE (elim_regs); i++)
3570 if (elim_regs[i].from == ARG_POINTER_REGNUM
3571 && elim_regs[i].to == HARD_FRAME_POINTER_REGNUM)
3574 if (i == ARRAY_SIZE (elim_regs))
3577 /* Now restore our arg pointer from the address at which it
3578 was saved in our stack frame. */
3579 emit_move_insn (virtual_incoming_args_rtx,
3580 copy_to_reg (get_arg_pointer_save_area (cfun)));
3585 #ifdef HAVE_nonlocal_goto_receiver
3586 if (HAVE_nonlocal_goto_receiver)
3587 emit_insn (gen_nonlocal_goto_receiver ());
3591 /* Make handlers for nonlocal gotos taking place in the function calls in
3595 expand_nl_goto_receivers (struct nesting *thisblock)
3598 rtx afterward = gen_label_rtx ();
3603 /* Record the handler address in the stack slot for that purpose,
3604 during this block, saving and restoring the outer value. */
3605 if (thisblock->next != 0)
3606 for (slot = nonlocal_goto_handler_slots; slot; slot = XEXP (slot, 1))
3608 rtx save_receiver = gen_reg_rtx (Pmode);
3609 emit_move_insn (XEXP (slot, 0), save_receiver);
3612 emit_move_insn (save_receiver, XEXP (slot, 0));
3613 insns = get_insns ();
3615 emit_insn_before (insns, thisblock->data.block.first_insn);
3618 /* Jump around the handlers; they run only when specially invoked. */
3619 emit_jump (afterward);
3621 /* Make a separate handler for each label. */
3622 link = nonlocal_labels;
3623 slot = nonlocal_goto_handler_slots;
3624 label_list = NULL_RTX;
3625 for (; link; link = TREE_CHAIN (link), slot = XEXP (slot, 1))
3626 /* Skip any labels we shouldn't be able to jump to from here,
3627 we generate one special handler for all of them below which just calls
3629 if (! DECL_TOO_LATE (TREE_VALUE (link)))
3632 lab = expand_nl_handler_label (XEXP (slot, 0),
3633 thisblock->data.block.first_insn);
3634 label_list = gen_rtx_EXPR_LIST (VOIDmode, lab, label_list);
3636 expand_nl_goto_receiver ();
3638 /* Jump to the "real" nonlocal label. */
3639 expand_goto (TREE_VALUE (link));
3642 /* A second pass over all nonlocal labels; this time we handle those
3643 we should not be able to jump to at this point. */
3644 link = nonlocal_labels;
3645 slot = nonlocal_goto_handler_slots;
3647 for (; link; link = TREE_CHAIN (link), slot = XEXP (slot, 1))
3648 if (DECL_TOO_LATE (TREE_VALUE (link)))
3651 lab = expand_nl_handler_label (XEXP (slot, 0),
3652 thisblock->data.block.first_insn);
3653 label_list = gen_rtx_EXPR_LIST (VOIDmode, lab, label_list);
3659 expand_nl_goto_receiver ();
3660 expand_builtin_trap ();
3663 nonlocal_goto_handler_labels = label_list;
3664 emit_label (afterward);
3667 /* Warn about any unused VARS (which may contain nodes other than
3668 VAR_DECLs, but such nodes are ignored). The nodes are connected
3669 via the TREE_CHAIN field. */
3672 warn_about_unused_variables (tree vars)
3676 if (warn_unused_variable)
3677 for (decl = vars; decl; decl = TREE_CHAIN (decl))
3678 if (TREE_CODE (decl) == VAR_DECL
3679 && ! TREE_USED (decl)
3680 && ! DECL_IN_SYSTEM_HEADER (decl)
3681 && DECL_NAME (decl) && ! DECL_ARTIFICIAL (decl))
3682 warning ("%Junused variable '%D'", decl, decl);
3685 /* Generate RTL code to terminate a binding contour.
3687 VARS is the chain of VAR_DECL nodes for the variables bound in this
3688 contour. There may actually be other nodes in this chain, but any
3689 nodes other than VAR_DECLS are ignored.
3691 MARK_ENDS is nonzero if we should put a note at the beginning
3692 and end of this binding contour.
3694 DONT_JUMP_IN is positive if it is not valid to jump into this contour,
3695 zero if we can jump into this contour only if it does not have a saved
3696 stack level, and negative if we are not to check for invalid use of
3697 labels (because the front end does that). */
3700 expand_end_bindings (tree vars, int mark_ends, int dont_jump_in)
3702 struct nesting *thisblock = block_stack;
3704 /* If any of the variables in this scope were not used, warn the
3706 warn_about_unused_variables (vars);
3708 if (thisblock->exit_label)
3710 do_pending_stack_adjust ();
3711 emit_label (thisblock->exit_label);
3714 /* If necessary, make handlers for nonlocal gotos taking
3715 place in the function calls in this block. */
3716 if (function_call_count != 0 && nonlocal_labels
3717 /* Make handler for outermost block
3718 if there were any nonlocal gotos to this function. */
3719 && (thisblock->next == 0 ? current_function_has_nonlocal_label
3720 /* Make handler for inner block if it has something
3721 special to do when you jump out of it. */
3722 : (thisblock->data.block.cleanups != 0
3723 || thisblock->data.block.stack_level != 0)))
3724 expand_nl_goto_receivers (thisblock);
3726 /* Don't allow jumping into a block that has a stack level.
3727 Cleanups are allowed, though. */
3728 if (dont_jump_in > 0
3729 || (dont_jump_in == 0 && thisblock->data.block.stack_level != 0))
3731 struct label_chain *chain;
3733 /* Any labels in this block are no longer valid to go to.
3734 Mark them to cause an error message. */
3735 for (chain = thisblock->data.block.label_chain; chain; chain = chain->next)
3737 DECL_TOO_LATE (chain->label) = 1;
3738 /* If any goto without a fixup came to this label,
3739 that must be an error, because gotos without fixups
3740 come from outside all saved stack-levels. */
3741 if (TREE_ADDRESSABLE (chain->label))
3742 error ("%Jlabel '%D' used before containing binding contour",
3743 chain->label, chain->label);
3747 /* Restore stack level in effect before the block
3748 (only if variable-size objects allocated). */
3749 /* Perform any cleanups associated with the block. */
3751 if (thisblock->data.block.stack_level != 0
3752 || thisblock->data.block.cleanups != 0)
3757 /* Don't let cleanups affect ({...}) constructs. */
3758 int old_expr_stmts_for_value = expr_stmts_for_value;
3759 rtx old_last_expr_value = last_expr_value;
3760 tree old_last_expr_type = last_expr_type;
3761 expr_stmts_for_value = 0;
3763 /* Only clean up here if this point can actually be reached. */
3764 insn = get_last_insn ();
3765 if (GET_CODE (insn) == NOTE)
3766 insn = prev_nonnote_insn (insn);
3767 reachable = (! insn || GET_CODE (insn) != BARRIER);
3769 /* Do the cleanups. */
3770 expand_cleanups (thisblock->data.block.cleanups, 0, reachable);
3772 do_pending_stack_adjust ();
3774 expr_stmts_for_value = old_expr_stmts_for_value;
3775 last_expr_value = old_last_expr_value;
3776 last_expr_type = old_last_expr_type;
3778 /* Restore the stack level. */
3780 if (reachable && thisblock->data.block.stack_level != 0)
3782 emit_stack_restore (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3783 thisblock->data.block.stack_level, NULL_RTX);
3784 if (nonlocal_goto_handler_slots != 0)
3785 emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level,
3789 /* Any gotos out of this block must also do these things.
3790 Also report any gotos with fixups that came to labels in this
3792 fixup_gotos (thisblock,
3793 thisblock->data.block.stack_level,
3794 thisblock->data.block.cleanups,
3795 thisblock->data.block.first_insn,
3799 /* Mark the beginning and end of the scope if requested.
3800 We do this now, after running cleanups on the variables
3801 just going out of scope, so they are in scope for their cleanups. */
3805 rtx note = emit_note (NOTE_INSN_BLOCK_END);
3806 NOTE_BLOCK (note) = NOTE_BLOCK (thisblock->data.block.first_insn);
3809 /* Get rid of the beginning-mark if we don't make an end-mark. */
3810 NOTE_LINE_NUMBER (thisblock->data.block.first_insn) = NOTE_INSN_DELETED;
3812 /* Restore the temporary level of TARGET_EXPRs. */
3813 target_temp_slot_level = thisblock->data.block.block_target_temp_slot_level;
3815 /* Restore block_stack level for containing block. */
3817 stack_block_stack = thisblock->data.block.innermost_stack_block;
3818 POPSTACK (block_stack);
3820 /* Pop the stack slot nesting and free any slots at this level. */
3824 /* Generate code to save the stack pointer at the start of the current block
3825 and set up to restore it on exit. */
3828 save_stack_pointer (void)
3830 struct nesting *thisblock = block_stack;
3832 if (thisblock->data.block.stack_level == 0)
3834 emit_stack_save (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3835 &thisblock->data.block.stack_level,
3836 thisblock->data.block.first_insn);
3837 stack_block_stack = thisblock;
3841 /* Generate RTL for the automatic variable declaration DECL.
3842 (Other kinds of declarations are simply ignored if seen here.) */
3845 expand_decl (tree decl)
3849 type = TREE_TYPE (decl);
3851 /* For a CONST_DECL, set mode, alignment, and sizes from those of the
3852 type in case this node is used in a reference. */
3853 if (TREE_CODE (decl) == CONST_DECL)
3855 DECL_MODE (decl) = TYPE_MODE (type);
3856 DECL_ALIGN (decl) = TYPE_ALIGN (type);
3857 DECL_SIZE (decl) = TYPE_SIZE (type);
3858 DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (type);
3862 /* Otherwise, only automatic variables need any expansion done. Static and
3863 external variables, and external functions, will be handled by
3864 `assemble_variable' (called from finish_decl). TYPE_DECL requires
3865 nothing. PARM_DECLs are handled in `assign_parms'. */
3866 if (TREE_CODE (decl) != VAR_DECL)
3869 if (TREE_STATIC (decl) || DECL_EXTERNAL (decl))
3872 /* Create the RTL representation for the variable. */
3874 if (type == error_mark_node)
3875 SET_DECL_RTL (decl, gen_rtx_MEM (BLKmode, const0_rtx));
3877 else if (DECL_SIZE (decl) == 0)
3878 /* Variable with incomplete type. */
3881 if (DECL_INITIAL (decl) == 0)
3882 /* Error message was already done; now avoid a crash. */
3883 x = gen_rtx_MEM (BLKmode, const0_rtx);
3885 /* An initializer is going to decide the size of this array.
3886 Until we know the size, represent its address with a reg. */
3887 x = gen_rtx_MEM (BLKmode, gen_reg_rtx (Pmode));
3889 set_mem_attributes (x, decl, 1);
3890 SET_DECL_RTL (decl, x);
3892 else if (DECL_MODE (decl) != BLKmode
3893 /* If -ffloat-store, don't put explicit float vars
3895 && !(flag_float_store
3896 && TREE_CODE (type) == REAL_TYPE)
3897 && ! TREE_THIS_VOLATILE (decl)
3898 && ! DECL_NONLOCAL (decl)
3899 && (DECL_REGISTER (decl) || DECL_ARTIFICIAL (decl) || optimize))
3901 /* Automatic variable that can go in a register. */
3902 int unsignedp = TREE_UNSIGNED (type);
3903 enum machine_mode reg_mode
3904 = promote_mode (type, DECL_MODE (decl), &unsignedp, 0);
3906 SET_DECL_RTL (decl, gen_reg_rtx (reg_mode));
3908 if (!DECL_ARTIFICIAL (decl))
3909 mark_user_reg (DECL_RTL (decl));
3911 if (POINTER_TYPE_P (type))
3912 mark_reg_pointer (DECL_RTL (decl),
3913 TYPE_ALIGN (TREE_TYPE (TREE_TYPE (decl))));
3915 maybe_set_unchanging (DECL_RTL (decl), decl);
3917 /* If something wants our address, try to use ADDRESSOF. */
3918 if (TREE_ADDRESSABLE (decl))
3919 put_var_into_stack (decl, /*rescan=*/false);
3922 else if (TREE_CODE (DECL_SIZE_UNIT (decl)) == INTEGER_CST
3923 && ! (flag_stack_check && ! STACK_CHECK_BUILTIN
3924 && 0 < compare_tree_int (DECL_SIZE_UNIT (decl),
3925 STACK_CHECK_MAX_VAR_SIZE)))
3927 /* Variable of fixed size that goes on the stack. */
3932 /* If we previously made RTL for this decl, it must be an array
3933 whose size was determined by the initializer.
3934 The old address was a register; set that register now
3935 to the proper address. */
3936 if (DECL_RTL_SET_P (decl))
3938 if (GET_CODE (DECL_RTL (decl)) != MEM
3939 || GET_CODE (XEXP (DECL_RTL (decl), 0)) != REG)
3941 oldaddr = XEXP (DECL_RTL (decl), 0);
3944 /* Set alignment we actually gave this decl. */
3945 DECL_ALIGN (decl) = (DECL_MODE (decl) == BLKmode ? BIGGEST_ALIGNMENT
3946 : GET_MODE_BITSIZE (DECL_MODE (decl)));
3947 DECL_USER_ALIGN (decl) = 0;
3949 x = assign_temp (decl, 1, 1, 1);
3950 set_mem_attributes (x, decl, 1);
3951 SET_DECL_RTL (decl, x);
3955 addr = force_operand (XEXP (DECL_RTL (decl), 0), oldaddr);
3956 if (addr != oldaddr)
3957 emit_move_insn (oldaddr, addr);
3961 /* Dynamic-size object: must push space on the stack. */
3963 rtx address, size, x;
3965 /* Record the stack pointer on entry to block, if have
3966 not already done so. */
3967 do_pending_stack_adjust ();
3968 save_stack_pointer ();
3970 /* In function-at-a-time mode, variable_size doesn't expand this,
3972 if (TREE_CODE (type) == ARRAY_TYPE && TYPE_DOMAIN (type))
3973 expand_expr (TYPE_MAX_VALUE (TYPE_DOMAIN (type)),
3974 const0_rtx, VOIDmode, 0);
3976 /* Compute the variable's size, in bytes. */
3977 size = expand_expr (DECL_SIZE_UNIT (decl), NULL_RTX, VOIDmode, 0);
3980 /* Allocate space on the stack for the variable. Note that
3981 DECL_ALIGN says how the variable is to be aligned and we
3982 cannot use it to conclude anything about the alignment of
3984 address = allocate_dynamic_stack_space (size, NULL_RTX,
3985 TYPE_ALIGN (TREE_TYPE (decl)));
3987 /* Reference the variable indirect through that rtx. */
3988 x = gen_rtx_MEM (DECL_MODE (decl), address);
3989 set_mem_attributes (x, decl, 1);
3990 SET_DECL_RTL (decl, x);
3993 /* Indicate the alignment we actually gave this variable. */
3994 #ifdef STACK_BOUNDARY
3995 DECL_ALIGN (decl) = STACK_BOUNDARY;
3997 DECL_ALIGN (decl) = BIGGEST_ALIGNMENT;
3999 DECL_USER_ALIGN (decl) = 0;
4003 /* Emit code to perform the initialization of a declaration DECL. */
4006 expand_decl_init (tree decl)
4008 int was_used = TREE_USED (decl);
4010 /* If this is a CONST_DECL, we don't have to generate any code. Likewise
4011 for static decls. */
4012 if (TREE_CODE (decl) == CONST_DECL
4013 || TREE_STATIC (decl))
4016 /* Compute and store the initial value now. */
4020 if (DECL_INITIAL (decl) == error_mark_node)
4022 enum tree_code code = TREE_CODE (TREE_TYPE (decl));
4024 if (code == INTEGER_TYPE || code == REAL_TYPE || code == ENUMERAL_TYPE
4025 || code == POINTER_TYPE || code == REFERENCE_TYPE)
4026 expand_assignment (decl, convert (TREE_TYPE (decl), integer_zero_node),
4030 else if (DECL_INITIAL (decl) && TREE_CODE (DECL_INITIAL (decl)) != TREE_LIST)
4032 emit_line_note (DECL_SOURCE_LOCATION (decl));
4033 expand_assignment (decl, DECL_INITIAL (decl), 0);
4037 /* Don't let the initialization count as "using" the variable. */
4038 TREE_USED (decl) = was_used;
4040 /* Free any temporaries we made while initializing the decl. */
4041 preserve_temp_slots (NULL_RTX);
4046 /* CLEANUP is an expression to be executed at exit from this binding contour;
4047 for example, in C++, it might call the destructor for this variable.
4049 We wrap CLEANUP in an UNSAVE_EXPR node, so that we can expand the
4050 CLEANUP multiple times, and have the correct semantics. This
4051 happens in exception handling, for gotos, returns, breaks that
4052 leave the current scope.
4054 If CLEANUP is nonzero and DECL is zero, we record a cleanup
4055 that is not associated with any particular variable. */
4058 expand_decl_cleanup (tree decl, tree cleanup)
4060 struct nesting *thisblock;
4062 /* Error if we are not in any block. */
4063 if (cfun == 0 || block_stack == 0)
4066 thisblock = block_stack;
4068 /* Record the cleanup if there is one. */
4074 tree *cleanups = &thisblock->data.block.cleanups;
4075 int cond_context = conditional_context ();
4079 rtx flag = gen_reg_rtx (word_mode);
4084 emit_move_insn (flag, const0_rtx);
4085 set_flag_0 = get_insns ();
4088 thisblock->data.block.last_unconditional_cleanup
4089 = emit_insn_after (set_flag_0,
4090 thisblock->data.block.last_unconditional_cleanup);
4092 emit_move_insn (flag, const1_rtx);
4094 cond = build_decl (VAR_DECL, NULL_TREE,
4095 (*lang_hooks.types.type_for_mode) (word_mode, 1));
4096 SET_DECL_RTL (cond, flag);
4098 /* Conditionalize the cleanup. */
4099 cleanup = build (COND_EXPR, void_type_node,
4100 (*lang_hooks.truthvalue_conversion) (cond),
4101 cleanup, integer_zero_node);
4102 cleanup = fold (cleanup);
4104 cleanups = &thisblock->data.block.cleanups;
4107 cleanup = unsave_expr (cleanup);
4109 t = *cleanups = tree_cons (decl, cleanup, *cleanups);
4112 /* If this block has a cleanup, it belongs in stack_block_stack. */
4113 stack_block_stack = thisblock;
4120 if (! using_eh_for_cleanups_p)
4121 TREE_ADDRESSABLE (t) = 1;
4123 expand_eh_region_start ();
4130 thisblock->data.block.last_unconditional_cleanup
4131 = emit_insn_after (seq,
4132 thisblock->data.block.last_unconditional_cleanup);
4136 thisblock->data.block.last_unconditional_cleanup
4138 /* When we insert instructions after the last unconditional cleanup,
4139 we don't adjust last_insn. That means that a later add_insn will
4140 clobber the instructions we've just added. The easiest way to
4141 fix this is to just insert another instruction here, so that the
4142 instructions inserted after the last unconditional cleanup are
4143 never the last instruction. */
4144 emit_note (NOTE_INSN_DELETED);
4150 /* Like expand_decl_cleanup, but maybe only run the cleanup if an exception
4154 expand_decl_cleanup_eh (tree decl, tree cleanup, int eh_only)
4156 int ret = expand_decl_cleanup (decl, cleanup);
4159 tree node = block_stack->data.block.cleanups;
4160 CLEANUP_EH_ONLY (node) = eh_only;
4165 /* DECL is an anonymous union. CLEANUP is a cleanup for DECL.
4166 DECL_ELTS is the list of elements that belong to DECL's type.
4167 In each, the TREE_VALUE is a VAR_DECL, and the TREE_PURPOSE a cleanup. */
4170 expand_anon_union_decl (tree decl, tree cleanup, tree decl_elts)
4172 struct nesting *thisblock = cfun == 0 ? 0 : block_stack;
4176 /* If any of the elements are addressable, so is the entire union. */
4177 for (t = decl_elts; t; t = TREE_CHAIN (t))
4178 if (TREE_ADDRESSABLE (TREE_VALUE (t)))
4180 TREE_ADDRESSABLE (decl) = 1;
4185 expand_decl_cleanup (decl, cleanup);
4186 x = DECL_RTL (decl);
4188 /* Go through the elements, assigning RTL to each. */
4189 for (t = decl_elts; t; t = TREE_CHAIN (t))
4191 tree decl_elt = TREE_VALUE (t);
4192 tree cleanup_elt = TREE_PURPOSE (t);
4193 enum machine_mode mode = TYPE_MODE (TREE_TYPE (decl_elt));
4195 /* If any of the elements are addressable, so is the entire
4197 if (TREE_USED (decl_elt))
4198 TREE_USED (decl) = 1;
4200 /* Propagate the union's alignment to the elements. */
4201 DECL_ALIGN (decl_elt) = DECL_ALIGN (decl);
4202 DECL_USER_ALIGN (decl_elt) = DECL_USER_ALIGN (decl);
4204 /* If the element has BLKmode and the union doesn't, the union is
4205 aligned such that the element doesn't need to have BLKmode, so
4206 change the element's mode to the appropriate one for its size. */
4207 if (mode == BLKmode && DECL_MODE (decl) != BLKmode)
4208 DECL_MODE (decl_elt) = mode
4209 = mode_for_size_tree (DECL_SIZE (decl_elt), MODE_INT, 1);
4211 /* (SUBREG (MEM ...)) at RTL generation time is invalid, so we
4212 instead create a new MEM rtx with the proper mode. */
4213 if (GET_CODE (x) == MEM)
4215 if (mode == GET_MODE (x))
4216 SET_DECL_RTL (decl_elt, x);
4218 SET_DECL_RTL (decl_elt, adjust_address_nv (x, mode, 0));
4220 else if (GET_CODE (x) == REG)
4222 if (mode == GET_MODE (x))
4223 SET_DECL_RTL (decl_elt, x);
4225 SET_DECL_RTL (decl_elt, gen_lowpart_SUBREG (mode, x));
4230 /* Record the cleanup if there is one. */
4233 thisblock->data.block.cleanups
4234 = tree_cons (decl_elt, cleanup_elt,
4235 thisblock->data.block.cleanups);
4239 /* Expand a list of cleanups LIST.
4240 Elements may be expressions or may be nested lists.
4242 If IN_FIXUP is nonzero, we are generating this cleanup for a fixup
4243 goto and handle protection regions specially in that case.
4245 If REACHABLE, we emit code, otherwise just inform the exception handling
4246 code about this finalization. */
4249 expand_cleanups (tree list, int in_fixup, int reachable)
4252 for (tail = list; tail; tail = TREE_CHAIN (tail))
4253 if (TREE_CODE (TREE_VALUE (tail)) == TREE_LIST)
4254 expand_cleanups (TREE_VALUE (tail), in_fixup, reachable);
4257 if (! in_fixup && using_eh_for_cleanups_p)
4258 expand_eh_region_end_cleanup (TREE_VALUE (tail));
4260 if (reachable && !CLEANUP_EH_ONLY (tail))
4262 /* Cleanups may be run multiple times. For example,
4263 when exiting a binding contour, we expand the
4264 cleanups associated with that contour. When a goto
4265 within that binding contour has a target outside that
4266 contour, it will expand all cleanups from its scope to
4267 the target. Though the cleanups are expanded multiple
4268 times, the control paths are non-overlapping so the
4269 cleanups will not be executed twice. */
4271 /* We may need to protect from outer cleanups. */
4272 if (in_fixup && using_eh_for_cleanups_p)
4274 expand_eh_region_start ();
4276 expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0);
4278 expand_eh_region_end_fixup (TREE_VALUE (tail));
4281 expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0);
4288 /* Mark when the context we are emitting RTL for as a conditional
4289 context, so that any cleanup actions we register with
4290 expand_decl_init will be properly conditionalized when those
4291 cleanup actions are later performed. Must be called before any
4292 expression (tree) is expanded that is within a conditional context. */
4295 start_cleanup_deferral (void)
4297 /* block_stack can be NULL if we are inside the parameter list. It is
4298 OK to do nothing, because cleanups aren't possible here. */
4300 ++block_stack->data.block.conditional_code;
4303 /* Mark the end of a conditional region of code. Because cleanup
4304 deferrals may be nested, we may still be in a conditional region
4305 after we end the currently deferred cleanups, only after we end all
4306 deferred cleanups, are we back in unconditional code. */
4309 end_cleanup_deferral (void)
4311 /* block_stack can be NULL if we are inside the parameter list. It is
4312 OK to do nothing, because cleanups aren't possible here. */
4314 --block_stack->data.block.conditional_code;
4318 last_cleanup_this_contour (void)
4320 if (block_stack == 0)
4323 return block_stack->data.block.cleanups;
4326 /* Return 1 if there are any pending cleanups at this point.
4327 Check the current contour as well as contours that enclose
4328 the current contour. */
4331 any_pending_cleanups (void)
4333 struct nesting *block;
4335 if (cfun == NULL || cfun->stmt == NULL || block_stack == 0)
4338 if (block_stack->data.block.cleanups != NULL)
4341 if (block_stack->data.block.outer_cleanups == 0)
4344 for (block = block_stack->next; block; block = block->next)
4345 if (block->data.block.cleanups != 0)
4351 /* Enter a case (Pascal) or switch (C) statement.
4352 Push a block onto case_stack and nesting_stack
4353 to accumulate the case-labels that are seen
4354 and to record the labels generated for the statement.
4356 EXIT_FLAG is nonzero if `exit_something' should exit this case stmt.
4357 Otherwise, this construct is transparent for `exit_something'.
4359 EXPR is the index-expression to be dispatched on.
4360 TYPE is its nominal type. We could simply convert EXPR to this type,
4361 but instead we take short cuts. */
4364 expand_start_case (int exit_flag, tree expr, tree type,
4365 const char *printname)
4367 struct nesting *thiscase = ALLOC_NESTING ();
4369 /* Make an entry on case_stack for the case we are entering. */
4371 thiscase->desc = CASE_NESTING;
4372 thiscase->next = case_stack;
4373 thiscase->all = nesting_stack;
4374 thiscase->depth = ++nesting_depth;
4375 thiscase->exit_label = exit_flag ? gen_label_rtx () : 0;
4376 thiscase->data.case_stmt.case_list = 0;
4377 thiscase->data.case_stmt.index_expr = expr;
4378 thiscase->data.case_stmt.nominal_type = type;
4379 thiscase->data.case_stmt.default_label = 0;
4380 thiscase->data.case_stmt.printname = printname;
4381 thiscase->data.case_stmt.line_number_status = force_line_numbers ();
4382 case_stack = thiscase;
4383 nesting_stack = thiscase;
4385 do_pending_stack_adjust ();
4388 /* Make sure case_stmt.start points to something that won't
4389 need any transformation before expand_end_case. */
4390 if (GET_CODE (get_last_insn ()) != NOTE)
4391 emit_note (NOTE_INSN_DELETED);
4393 thiscase->data.case_stmt.start = get_last_insn ();
4395 start_cleanup_deferral ();
4398 /* Start a "dummy case statement" within which case labels are invalid
4399 and are not connected to any larger real case statement.
4400 This can be used if you don't want to let a case statement jump
4401 into the middle of certain kinds of constructs. */
4404 expand_start_case_dummy (void)
4406 struct nesting *thiscase = ALLOC_NESTING ();
4408 /* Make an entry on case_stack for the dummy. */
4410 thiscase->desc = CASE_NESTING;
4411 thiscase->next = case_stack;
4412 thiscase->all = nesting_stack;
4413 thiscase->depth = ++nesting_depth;
4414 thiscase->exit_label = 0;
4415 thiscase->data.case_stmt.case_list = 0;
4416 thiscase->data.case_stmt.start = 0;
4417 thiscase->data.case_stmt.nominal_type = 0;
4418 thiscase->data.case_stmt.default_label = 0;
4419 case_stack = thiscase;
4420 nesting_stack = thiscase;
4421 start_cleanup_deferral ();
4425 check_seenlabel (void)
4427 /* If this is the first label, warn if any insns have been emitted. */
4428 if (case_stack->data.case_stmt.line_number_status >= 0)
4432 restore_line_number_status
4433 (case_stack->data.case_stmt.line_number_status);
4434 case_stack->data.case_stmt.line_number_status = -1;
4436 for (insn = case_stack->data.case_stmt.start;
4438 insn = NEXT_INSN (insn))
4440 if (GET_CODE (insn) == CODE_LABEL)
4442 if (GET_CODE (insn) != NOTE
4443 && (GET_CODE (insn) != INSN || GET_CODE (PATTERN (insn)) != USE))
4446 insn = PREV_INSN (insn);
4447 while (insn && (GET_CODE (insn) != NOTE || NOTE_LINE_NUMBER (insn) < 0));
4449 /* If insn is zero, then there must have been a syntax error. */
4453 locus.file = NOTE_SOURCE_FILE (insn);
4454 locus.line = NOTE_LINE_NUMBER (insn);
4455 warning ("%Hunreachable code at beginning of %s", &locus,
4456 case_stack->data.case_stmt.printname);
4464 /* Accumulate one case or default label inside a case or switch statement.
4465 VALUE is the value of the case (a null pointer, for a default label).
4466 The function CONVERTER, when applied to arguments T and V,
4467 converts the value V to the type T.
4469 If not currently inside a case or switch statement, return 1 and do
4470 nothing. The caller will print a language-specific error message.
4471 If VALUE is a duplicate or overlaps, return 2 and do nothing
4472 except store the (first) duplicate node in *DUPLICATE.
4473 If VALUE is out of range, return 3 and do nothing.
4474 If we are jumping into the scope of a cleanup or var-sized array, return 5.
4475 Return 0 on success.
4477 Extended to handle range statements. */
4480 pushcase (tree value, tree (*converter) (tree, tree), tree label,
4486 /* Fail if not inside a real case statement. */
4487 if (! (case_stack && case_stack->data.case_stmt.start))
4490 if (stack_block_stack
4491 && stack_block_stack->depth > case_stack->depth)
4494 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
4495 nominal_type = case_stack->data.case_stmt.nominal_type;
4497 /* If the index is erroneous, avoid more problems: pretend to succeed. */
4498 if (index_type == error_mark_node)
4501 /* Convert VALUE to the type in which the comparisons are nominally done. */
4503 value = (*converter) (nominal_type, value);
4507 /* Fail if this value is out of range for the actual type of the index
4508 (which may be narrower than NOMINAL_TYPE). */
4510 && (TREE_CONSTANT_OVERFLOW (value)
4511 || ! int_fits_type_p (value, index_type)))
4514 return add_case_node (value, value, label, duplicate);
4517 /* Like pushcase but this case applies to all values between VALUE1 and
4518 VALUE2 (inclusive). If VALUE1 is NULL, the range starts at the lowest
4519 value of the index type and ends at VALUE2. If VALUE2 is NULL, the range
4520 starts at VALUE1 and ends at the highest value of the index type.
4521 If both are NULL, this case applies to all values.
4523 The return value is the same as that of pushcase but there is one
4524 additional error code: 4 means the specified range was empty. */
4527 pushcase_range (tree value1, tree value2, tree (*converter) (tree, tree),
4528 tree label, tree *duplicate)
4533 /* Fail if not inside a real case statement. */
4534 if (! (case_stack && case_stack->data.case_stmt.start))
4537 if (stack_block_stack
4538 && stack_block_stack->depth > case_stack->depth)
4541 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
4542 nominal_type = case_stack->data.case_stmt.nominal_type;
4544 /* If the index is erroneous, avoid more problems: pretend to succeed. */
4545 if (index_type == error_mark_node)
4550 /* Convert VALUEs to type in which the comparisons are nominally done
4551 and replace any unspecified value with the corresponding bound. */
4553 value1 = TYPE_MIN_VALUE (index_type);
4555 value2 = TYPE_MAX_VALUE (index_type);
4557 /* Fail if the range is empty. Do this before any conversion since
4558 we want to allow out-of-range empty ranges. */
4559 if (value2 != 0 && tree_int_cst_lt (value2, value1))
4562 /* If the max was unbounded, use the max of the nominal_type we are
4563 converting to. Do this after the < check above to suppress false
4566 value2 = TYPE_MAX_VALUE (nominal_type);
4568 value1 = (*converter) (nominal_type, value1);
4569 value2 = (*converter) (nominal_type, value2);
4571 /* Fail if these values are out of range. */
4572 if (TREE_CONSTANT_OVERFLOW (value1)
4573 || ! int_fits_type_p (value1, index_type))
4576 if (TREE_CONSTANT_OVERFLOW (value2)
4577 || ! int_fits_type_p (value2, index_type))
4580 return add_case_node (value1, value2, label, duplicate);
4583 /* Do the actual insertion of a case label for pushcase and pushcase_range
4584 into case_stack->data.case_stmt.case_list. Use an AVL tree to avoid
4585 slowdown for large switch statements. */
4588 add_case_node (tree low, tree high, tree label, tree *duplicate)
4590 struct case_node *p, **q, *r;
4592 /* If there's no HIGH value, then this is not a case range; it's
4593 just a simple case label. But that's just a degenerate case
4598 /* Handle default labels specially. */
4601 if (case_stack->data.case_stmt.default_label != 0)
4603 *duplicate = case_stack->data.case_stmt.default_label;
4606 case_stack->data.case_stmt.default_label = label;
4607 expand_label (label);
4611 q = &case_stack->data.case_stmt.case_list;
4618 /* Keep going past elements distinctly greater than HIGH. */
4619 if (tree_int_cst_lt (high, p->low))
4622 /* or distinctly less than LOW. */
4623 else if (tree_int_cst_lt (p->high, low))
4628 /* We have an overlap; this is an error. */
4629 *duplicate = p->code_label;
4634 /* Add this label to the chain, and succeed. */
4636 r = ggc_alloc (sizeof (struct case_node));
4639 /* If the bounds are equal, turn this into the one-value case. */
4640 if (tree_int_cst_equal (low, high))
4645 r->code_label = label;
4646 expand_label (label);
4656 struct case_node *s;
4662 if (! (b = p->balance))
4663 /* Growth propagation from left side. */
4670 if ((p->left = s = r->right))
4679 if ((r->parent = s))
4687 case_stack->data.case_stmt.case_list = r;
4690 /* r->balance == +1 */
4695 struct case_node *t = r->right;
4697 if ((p->left = s = t->right))
4701 if ((r->right = s = t->left))
4715 if ((t->parent = s))
4723 case_stack->data.case_stmt.case_list = t;
4730 /* p->balance == +1; growth of left side balances the node. */
4740 if (! (b = p->balance))
4741 /* Growth propagation from right side. */
4749 if ((p->right = s = r->left))
4757 if ((r->parent = s))
4766 case_stack->data.case_stmt.case_list = r;
4770 /* r->balance == -1 */
4774 struct case_node *t = r->left;
4776 if ((p->right = s = t->left))
4781 if ((r->left = s = t->right))
4795 if ((t->parent = s))
4804 case_stack->data.case_stmt.case_list = t;
4810 /* p->balance == -1; growth of right side balances the node. */
4823 /* Returns the number of possible values of TYPE.
4824 Returns -1 if the number is unknown, variable, or if the number does not
4825 fit in a HOST_WIDE_INT.
4826 Sets *SPARSENESS to 2 if TYPE is an ENUMERAL_TYPE whose values
4827 do not increase monotonically (there may be duplicates);
4828 to 1 if the values increase monotonically, but not always by 1;
4829 otherwise sets it to 0. */
4832 all_cases_count (tree type, int *sparseness)
4835 HOST_WIDE_INT count, minval, lastval;
4839 switch (TREE_CODE (type))
4846 count = 1 << BITS_PER_UNIT;
4851 if (TYPE_MAX_VALUE (type) != 0
4852 && 0 != (t = fold (build (MINUS_EXPR, type, TYPE_MAX_VALUE (type),
4853 TYPE_MIN_VALUE (type))))
4854 && 0 != (t = fold (build (PLUS_EXPR, type, t,
4855 convert (type, integer_zero_node))))
4856 && host_integerp (t, 1))
4857 count = tree_low_cst (t, 1);
4863 /* Don't waste time with enumeral types with huge values. */
4864 if (! host_integerp (TYPE_MIN_VALUE (type), 0)
4865 || TYPE_MAX_VALUE (type) == 0
4866 || ! host_integerp (TYPE_MAX_VALUE (type), 0))
4869 lastval = minval = tree_low_cst (TYPE_MIN_VALUE (type), 0);
4872 for (t = TYPE_VALUES (type); t != NULL_TREE; t = TREE_CHAIN (t))
4874 HOST_WIDE_INT thisval = tree_low_cst (TREE_VALUE (t), 0);
4876 if (*sparseness == 2 || thisval <= lastval)
4878 else if (thisval != minval + count)
4889 #define BITARRAY_TEST(ARRAY, INDEX) \
4890 ((ARRAY)[(unsigned) (INDEX) / HOST_BITS_PER_CHAR]\
4891 & (1 << ((unsigned) (INDEX) % HOST_BITS_PER_CHAR)))
4892 #define BITARRAY_SET(ARRAY, INDEX) \
4893 ((ARRAY)[(unsigned) (INDEX) / HOST_BITS_PER_CHAR]\
4894 |= 1 << ((unsigned) (INDEX) % HOST_BITS_PER_CHAR))
4896 /* Set the elements of the bitstring CASES_SEEN (which has length COUNT),
4897 with the case values we have seen, assuming the case expression
4899 SPARSENESS is as determined by all_cases_count.
4901 The time needed is proportional to COUNT, unless
4902 SPARSENESS is 2, in which case quadratic time is needed. */
4905 mark_seen_cases (tree type, unsigned char *cases_seen, HOST_WIDE_INT count,
4908 tree next_node_to_try = NULL_TREE;
4909 HOST_WIDE_INT next_node_offset = 0;
4911 struct case_node *n, *root = case_stack->data.case_stmt.case_list;
4912 tree val = make_node (INTEGER_CST);
4914 TREE_TYPE (val) = type;
4918 else if (sparseness == 2)
4921 unsigned HOST_WIDE_INT xlo;
4923 /* This less efficient loop is only needed to handle
4924 duplicate case values (multiple enum constants
4925 with the same value). */
4926 TREE_TYPE (val) = TREE_TYPE (root->low);
4927 for (t = TYPE_VALUES (type), xlo = 0; t != NULL_TREE;
4928 t = TREE_CHAIN (t), xlo++)
4930 TREE_INT_CST_LOW (val) = TREE_INT_CST_LOW (TREE_VALUE (t));
4931 TREE_INT_CST_HIGH (val) = TREE_INT_CST_HIGH (TREE_VALUE (t));
4935 /* Keep going past elements distinctly greater than VAL. */
4936 if (tree_int_cst_lt (val, n->low))
4939 /* or distinctly less than VAL. */
4940 else if (tree_int_cst_lt (n->high, val))
4945 /* We have found a matching range. */
4946 BITARRAY_SET (cases_seen, xlo);
4956 case_stack->data.case_stmt.case_list = root = case_tree2list (root, 0);
4958 for (n = root; n; n = n->right)
4960 TREE_INT_CST_LOW (val) = TREE_INT_CST_LOW (n->low);
4961 TREE_INT_CST_HIGH (val) = TREE_INT_CST_HIGH (n->low);
4962 while (! tree_int_cst_lt (n->high, val))
4964 /* Calculate (into xlo) the "offset" of the integer (val).
4965 The element with lowest value has offset 0, the next smallest
4966 element has offset 1, etc. */
4968 unsigned HOST_WIDE_INT xlo;
4972 if (sparseness && TYPE_VALUES (type) != NULL_TREE)
4974 /* The TYPE_VALUES will be in increasing order, so
4975 starting searching where we last ended. */
4976 t = next_node_to_try;
4977 xlo = next_node_offset;
4983 t = TYPE_VALUES (type);
4986 if (tree_int_cst_equal (val, TREE_VALUE (t)))
4988 next_node_to_try = TREE_CHAIN (t);
4989 next_node_offset = xlo + 1;
4994 if (t == next_node_to_try)
5003 t = TYPE_MIN_VALUE (type);
5005 neg_double (TREE_INT_CST_LOW (t), TREE_INT_CST_HIGH (t),
5009 add_double (xlo, xhi,
5010 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val),
5014 if (xhi == 0 && xlo < (unsigned HOST_WIDE_INT) count)
5015 BITARRAY_SET (cases_seen, xlo);
5017 add_double (TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val),
5019 &TREE_INT_CST_LOW (val), &TREE_INT_CST_HIGH (val));
5025 /* Given a switch statement with an expression that is an enumeration
5026 type, warn if any of the enumeration type's literals are not
5027 covered by the case expressions of the switch. Also, warn if there
5028 are any extra switch cases that are *not* elements of the
5033 At one stage this function would: ``If all enumeration literals
5034 were covered by the case expressions, turn one of the expressions
5035 into the default expression since it should not be possible to fall
5036 through such a switch.''
5038 That code has since been removed as: ``This optimization is
5039 disabled because it causes valid programs to fail. ANSI C does not
5040 guarantee that an expression with enum type will have a value that
5041 is the same as one of the enumeration literals.'' */
5044 check_for_full_enumeration_handling (tree type)
5046 struct case_node *n;
5049 /* True iff the selector type is a numbered set mode. */
5052 /* The number of possible selector values. */
5055 /* For each possible selector value. a one iff it has been matched
5056 by a case value alternative. */
5057 unsigned char *cases_seen;
5059 /* The allocated size of cases_seen, in chars. */
5060 HOST_WIDE_INT bytes_needed;
5062 size = all_cases_count (type, &sparseness);
5063 bytes_needed = (size + HOST_BITS_PER_CHAR) / HOST_BITS_PER_CHAR;
5065 if (size > 0 && size < 600000
5066 /* We deliberately use calloc here, not cmalloc, so that we can suppress
5067 this optimization if we don't have enough memory rather than
5068 aborting, as xmalloc would do. */
5069 && (cases_seen = really_call_calloc (bytes_needed, 1)) != NULL)
5072 tree v = TYPE_VALUES (type);
5074 /* The time complexity of this code is normally O(N), where
5075 N being the number of members in the enumerated type.
5076 However, if type is an ENUMERAL_TYPE whose values do not
5077 increase monotonically, O(N*log(N)) time may be needed. */
5079 mark_seen_cases (type, cases_seen, size, sparseness);
5081 for (i = 0; v != NULL_TREE && i < size; i++, v = TREE_CHAIN (v))
5082 if (BITARRAY_TEST (cases_seen, i) == 0)
5083 warning ("enumeration value `%s' not handled in switch",
5084 IDENTIFIER_POINTER (TREE_PURPOSE (v)));
5089 /* Now we go the other way around; we warn if there are case
5090 expressions that don't correspond to enumerators. This can
5091 occur since C and C++ don't enforce type-checking of
5092 assignments to enumeration variables. */
5094 if (case_stack->data.case_stmt.case_list
5095 && case_stack->data.case_stmt.case_list->left)
5096 case_stack->data.case_stmt.case_list
5097 = case_tree2list (case_stack->data.case_stmt.case_list, 0);
5098 for (n = case_stack->data.case_stmt.case_list; n; n = n->right)
5100 for (chain = TYPE_VALUES (type);
5101 chain && !tree_int_cst_equal (n->low, TREE_VALUE (chain));
5102 chain = TREE_CHAIN (chain))
5107 if (TYPE_NAME (type) == 0)
5108 warning ("case value `%ld' not in enumerated type",
5109 (long) TREE_INT_CST_LOW (n->low));
5111 warning ("case value `%ld' not in enumerated type `%s'",
5112 (long) TREE_INT_CST_LOW (n->low),
5113 IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
5116 : DECL_NAME (TYPE_NAME (type))));
5118 if (!tree_int_cst_equal (n->low, n->high))
5120 for (chain = TYPE_VALUES (type);
5121 chain && !tree_int_cst_equal (n->high, TREE_VALUE (chain));
5122 chain = TREE_CHAIN (chain))
5127 if (TYPE_NAME (type) == 0)
5128 warning ("case value `%ld' not in enumerated type",
5129 (long) TREE_INT_CST_LOW (n->high));
5131 warning ("case value `%ld' not in enumerated type `%s'",
5132 (long) TREE_INT_CST_LOW (n->high),
5133 IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
5136 : DECL_NAME (TYPE_NAME (type))));
5143 /* Maximum number of case bit tests. */
5144 #define MAX_CASE_BIT_TESTS 3
5146 /* By default, enable case bit tests on targets with ashlsi3. */
5147 #ifndef CASE_USE_BIT_TESTS
5148 #define CASE_USE_BIT_TESTS (ashl_optab->handlers[word_mode].insn_code \
5149 != CODE_FOR_nothing)
5153 /* A case_bit_test represents a set of case nodes that may be
5154 selected from using a bit-wise comparison. HI and LO hold
5155 the integer to be tested against, LABEL contains the label
5156 to jump to upon success and BITS counts the number of case
5157 nodes handled by this test, typically the number of bits
5160 struct case_bit_test
5168 /* Determine whether "1 << x" is relatively cheap in word_mode. */
5171 bool lshift_cheap_p (void)
5173 static bool init = false;
5174 static bool cheap = true;
5178 rtx reg = gen_rtx_REG (word_mode, 10000);
5179 int cost = rtx_cost (gen_rtx_ASHIFT (word_mode, const1_rtx, reg), SET);
5180 cheap = cost < COSTS_N_INSNS (3);
5187 /* Comparison function for qsort to order bit tests by decreasing
5188 number of case nodes, i.e. the node with the most cases gets
5192 int case_bit_test_cmp (const void *p1, const void *p2)
5194 const struct case_bit_test *d1 = p1;
5195 const struct case_bit_test *d2 = p2;
5197 return d2->bits - d1->bits;
5200 /* Expand a switch statement by a short sequence of bit-wise
5201 comparisons. "switch(x)" is effectively converted into
5202 "if ((1 << (x-MINVAL)) & CST)" where CST and MINVAL are
5205 INDEX_EXPR is the value being switched on, which is of
5206 type INDEX_TYPE. MINVAL is the lowest case value of in
5207 the case nodes, of INDEX_TYPE type, and RANGE is highest
5208 value minus MINVAL, also of type INDEX_TYPE. NODES is
5209 the set of case nodes, and DEFAULT_LABEL is the label to
5210 branch to should none of the cases match.
5212 There *MUST* be MAX_CASE_BIT_TESTS or less unique case
5216 emit_case_bit_tests (tree index_type, tree index_expr, tree minval,
5217 tree range, case_node_ptr nodes, rtx default_label)
5219 struct case_bit_test test[MAX_CASE_BIT_TESTS];
5220 enum machine_mode mode;
5221 rtx expr, index, label;
5222 unsigned int i,j,lo,hi;
5223 struct case_node *n;
5227 for (n = nodes; n; n = n->right)
5229 label = label_rtx (n->code_label);
5230 for (i = 0; i < count; i++)
5231 if (same_case_target_p (label, test[i].label))
5236 if (count >= MAX_CASE_BIT_TESTS)
5240 test[i].label = label;
5247 lo = tree_low_cst (fold (build (MINUS_EXPR, index_type,
5248 n->low, minval)), 1);
5249 hi = tree_low_cst (fold (build (MINUS_EXPR, index_type,
5250 n->high, minval)), 1);
5251 for (j = lo; j <= hi; j++)
5252 if (j >= HOST_BITS_PER_WIDE_INT)
5253 test[i].hi |= (HOST_WIDE_INT) 1 << (j - HOST_BITS_PER_INT);
5255 test[i].lo |= (HOST_WIDE_INT) 1 << j;
5258 qsort (test, count, sizeof(*test), case_bit_test_cmp);
5260 index_expr = fold (build (MINUS_EXPR, index_type,
5261 convert (index_type, index_expr),
5262 convert (index_type, minval)));
5263 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
5265 index = protect_from_queue (index, 0);
5266 do_pending_stack_adjust ();
5268 mode = TYPE_MODE (index_type);
5269 expr = expand_expr (range, NULL_RTX, VOIDmode, 0);
5270 emit_cmp_and_jump_insns (index, expr, GTU, NULL_RTX, mode, 1,
5273 index = convert_to_mode (word_mode, index, 0);
5274 index = expand_binop (word_mode, ashl_optab, const1_rtx,
5275 index, NULL_RTX, 1, OPTAB_WIDEN);
5277 for (i = 0; i < count; i++)
5279 expr = immed_double_const (test[i].lo, test[i].hi, word_mode);
5280 expr = expand_binop (word_mode, and_optab, index, expr,
5281 NULL_RTX, 1, OPTAB_WIDEN);
5282 emit_cmp_and_jump_insns (expr, const0_rtx, NE, NULL_RTX,
5283 word_mode, 1, test[i].label);
5286 emit_jump (default_label);
5289 /* Terminate a case (Pascal) or switch (C) statement
5290 in which ORIG_INDEX is the expression to be tested.
5291 If ORIG_TYPE is not NULL, it is the original ORIG_INDEX
5292 type as given in the source before any compiler conversions.
5293 Generate the code to test it and jump to the right place. */
5296 expand_end_case_type (tree orig_index, tree orig_type)
5298 tree minval = NULL_TREE, maxval = NULL_TREE, range = NULL_TREE;
5299 rtx default_label = 0;
5300 struct case_node *n, *m;
5301 unsigned int count, uniq;
5307 rtx before_case, end, lab;
5308 struct nesting *thiscase = case_stack;
5309 tree index_expr, index_type;
5310 bool exit_done = false;
5313 /* Don't crash due to previous errors. */
5314 if (thiscase == NULL)
5317 index_expr = thiscase->data.case_stmt.index_expr;
5318 index_type = TREE_TYPE (index_expr);
5319 unsignedp = TREE_UNSIGNED (index_type);
5320 if (orig_type == NULL)
5321 orig_type = TREE_TYPE (orig_index);
5323 do_pending_stack_adjust ();
5325 /* This might get a spurious warning in the presence of a syntax error;
5326 it could be fixed by moving the call to check_seenlabel after the
5327 check for error_mark_node, and copying the code of check_seenlabel that
5328 deals with case_stack->data.case_stmt.line_number_status /
5329 restore_line_number_status in front of the call to end_cleanup_deferral;
5330 However, this might miss some useful warnings in the presence of
5331 non-syntax errors. */
5334 /* An ERROR_MARK occurs for various reasons including invalid data type. */
5335 if (index_type != error_mark_node)
5337 /* If the switch expression was an enumerated type, check that
5338 exactly all enumeration literals are covered by the cases.
5339 The check is made when -Wswitch was specified and there is no
5340 default case, or when -Wswitch-enum was specified. */
5341 if (((warn_switch && !thiscase->data.case_stmt.default_label)
5342 || warn_switch_enum)
5343 && TREE_CODE (orig_type) == ENUMERAL_TYPE
5344 && TREE_CODE (index_expr) != INTEGER_CST)
5345 check_for_full_enumeration_handling (orig_type);
5347 if (warn_switch_default && !thiscase->data.case_stmt.default_label)
5348 warning ("switch missing default case");
5350 /* If we don't have a default-label, create one here,
5351 after the body of the switch. */
5352 if (thiscase->data.case_stmt.default_label == 0)
5354 thiscase->data.case_stmt.default_label
5355 = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
5356 /* Share the exit label if possible. */
5357 if (thiscase->exit_label)
5359 SET_DECL_RTL (thiscase->data.case_stmt.default_label,
5360 thiscase->exit_label);
5363 expand_label (thiscase->data.case_stmt.default_label);
5365 default_label = label_rtx (thiscase->data.case_stmt.default_label);
5367 before_case = get_last_insn ();
5369 if (thiscase->data.case_stmt.case_list
5370 && thiscase->data.case_stmt.case_list->left)
5371 thiscase->data.case_stmt.case_list
5372 = case_tree2list (thiscase->data.case_stmt.case_list, 0);
5374 /* Simplify the case-list before we count it. */
5375 group_case_nodes (thiscase->data.case_stmt.case_list);
5376 strip_default_case_nodes (&thiscase->data.case_stmt.case_list,
5379 /* Get upper and lower bounds of case values.
5380 Also convert all the case values to the index expr's data type. */
5384 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5386 /* Check low and high label values are integers. */
5387 if (TREE_CODE (n->low) != INTEGER_CST)
5389 if (TREE_CODE (n->high) != INTEGER_CST)
5392 n->low = convert (index_type, n->low);
5393 n->high = convert (index_type, n->high);
5395 /* Count the elements and track the largest and smallest
5396 of them (treating them as signed even if they are not). */
5404 if (INT_CST_LT (n->low, minval))
5406 if (INT_CST_LT (maxval, n->high))
5409 /* A range counts double, since it requires two compares. */
5410 if (! tree_int_cst_equal (n->low, n->high))
5413 /* Count the number of unique case node targets. */
5415 lab = label_rtx (n->code_label);
5416 for (m = thiscase->data.case_stmt.case_list; m != n; m = m->right)
5417 if (same_case_target_p (label_rtx (m->code_label), lab))
5424 /* Compute span of values. */
5426 range = fold (build (MINUS_EXPR, index_type, maxval, minval));
5428 end_cleanup_deferral ();
5432 expand_expr (index_expr, const0_rtx, VOIDmode, 0);
5434 emit_jump (default_label);
5437 /* Try implementing this switch statement by a short sequence of
5438 bit-wise comparisons. However, we let the binary-tree case
5439 below handle constant index expressions. */
5440 else if (CASE_USE_BIT_TESTS
5441 && ! TREE_CONSTANT (index_expr)
5442 && compare_tree_int (range, GET_MODE_BITSIZE (word_mode)) < 0
5443 && compare_tree_int (range, 0) > 0
5444 && lshift_cheap_p ()
5445 && ((uniq == 1 && count >= 3)
5446 || (uniq == 2 && count >= 5)
5447 || (uniq == 3 && count >= 6)))
5449 /* Optimize the case where all the case values fit in a
5450 word without having to subtract MINVAL. In this case,
5451 we can optimize away the subtraction. */
5452 if (compare_tree_int (minval, 0) > 0
5453 && compare_tree_int (maxval, GET_MODE_BITSIZE (word_mode)) < 0)
5455 minval = integer_zero_node;
5458 emit_case_bit_tests (index_type, index_expr, minval, range,
5459 thiscase->data.case_stmt.case_list,
5463 /* If range of values is much bigger than number of values,
5464 make a sequence of conditional branches instead of a dispatch.
5465 If the switch-index is a constant, do it this way
5466 because we can optimize it. */
5468 else if (count < case_values_threshold ()
5469 || compare_tree_int (range,
5470 (optimize_size ? 3 : 10) * count) > 0
5471 /* RANGE may be signed, and really large ranges will show up
5472 as negative numbers. */
5473 || compare_tree_int (range, 0) < 0
5474 #ifndef ASM_OUTPUT_ADDR_DIFF_ELT
5477 || TREE_CONSTANT (index_expr))
5479 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
5481 /* If the index is a short or char that we do not have
5482 an insn to handle comparisons directly, convert it to
5483 a full integer now, rather than letting each comparison
5484 generate the conversion. */
5486 if (GET_MODE_CLASS (GET_MODE (index)) == MODE_INT
5487 && ! have_insn_for (COMPARE, GET_MODE (index)))
5489 enum machine_mode wider_mode;
5490 for (wider_mode = GET_MODE (index); wider_mode != VOIDmode;
5491 wider_mode = GET_MODE_WIDER_MODE (wider_mode))
5492 if (have_insn_for (COMPARE, wider_mode))
5494 index = convert_to_mode (wider_mode, index, unsignedp);
5500 do_pending_stack_adjust ();
5502 index = protect_from_queue (index, 0);
5503 if (GET_CODE (index) == MEM)
5504 index = copy_to_reg (index);
5505 if (GET_CODE (index) == CONST_INT
5506 || TREE_CODE (index_expr) == INTEGER_CST)
5508 /* Make a tree node with the proper constant value
5509 if we don't already have one. */
5510 if (TREE_CODE (index_expr) != INTEGER_CST)
5513 = build_int_2 (INTVAL (index),
5514 unsignedp || INTVAL (index) >= 0 ? 0 : -1);
5515 index_expr = convert (index_type, index_expr);
5518 /* For constant index expressions we need only
5519 issue an unconditional branch to the appropriate
5520 target code. The job of removing any unreachable
5521 code is left to the optimization phase if the
5522 "-O" option is specified. */
5523 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5524 if (! tree_int_cst_lt (index_expr, n->low)
5525 && ! tree_int_cst_lt (n->high, index_expr))
5529 emit_jump (label_rtx (n->code_label));
5531 emit_jump (default_label);
5535 /* If the index expression is not constant we generate
5536 a binary decision tree to select the appropriate
5537 target code. This is done as follows:
5539 The list of cases is rearranged into a binary tree,
5540 nearly optimal assuming equal probability for each case.
5542 The tree is transformed into RTL, eliminating
5543 redundant test conditions at the same time.
5545 If program flow could reach the end of the
5546 decision tree an unconditional jump to the
5547 default code is emitted. */
5550 = (TREE_CODE (orig_type) != ENUMERAL_TYPE
5551 && estimate_case_costs (thiscase->data.case_stmt.case_list));
5552 balance_case_nodes (&thiscase->data.case_stmt.case_list, NULL);
5553 emit_case_nodes (index, thiscase->data.case_stmt.case_list,
5554 default_label, index_type);
5555 emit_jump_if_reachable (default_label);
5560 table_label = gen_label_rtx ();
5561 if (! try_casesi (index_type, index_expr, minval, range,
5562 table_label, default_label))
5564 index_type = thiscase->data.case_stmt.nominal_type;
5566 /* Index jumptables from zero for suitable values of
5567 minval to avoid a subtraction. */
5569 && compare_tree_int (minval, 0) > 0
5570 && compare_tree_int (minval, 3) < 0)
5572 minval = integer_zero_node;
5576 if (! try_tablejump (index_type, index_expr, minval, range,
5577 table_label, default_label))
5581 /* Get table of labels to jump to, in order of case index. */
5583 ncases = tree_low_cst (range, 0) + 1;
5584 labelvec = alloca (ncases * sizeof (rtx));
5585 memset (labelvec, 0, ncases * sizeof (rtx));
5587 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5589 /* Compute the low and high bounds relative to the minimum
5590 value since that should fit in a HOST_WIDE_INT while the
5591 actual values may not. */
5593 = tree_low_cst (fold (build (MINUS_EXPR, index_type,
5594 n->low, minval)), 1);
5595 HOST_WIDE_INT i_high
5596 = tree_low_cst (fold (build (MINUS_EXPR, index_type,
5597 n->high, minval)), 1);
5600 for (i = i_low; i <= i_high; i ++)
5602 = gen_rtx_LABEL_REF (Pmode, label_rtx (n->code_label));
5605 /* Fill in the gaps with the default. */
5606 for (i = 0; i < ncases; i++)
5607 if (labelvec[i] == 0)
5608 labelvec[i] = gen_rtx_LABEL_REF (Pmode, default_label);
5610 /* Output the table. */
5611 emit_label (table_label);
5613 if (CASE_VECTOR_PC_RELATIVE || flag_pic)
5614 emit_jump_insn (gen_rtx_ADDR_DIFF_VEC (CASE_VECTOR_MODE,
5615 gen_rtx_LABEL_REF (Pmode, table_label),
5616 gen_rtvec_v (ncases, labelvec),
5617 const0_rtx, const0_rtx));
5619 emit_jump_insn (gen_rtx_ADDR_VEC (CASE_VECTOR_MODE,
5620 gen_rtvec_v (ncases, labelvec)));
5622 /* If the case insn drops through the table,
5623 after the table we must jump to the default-label.
5624 Otherwise record no drop-through after the table. */
5625 #ifdef CASE_DROPS_THROUGH
5626 emit_jump (default_label);
5632 before_case = NEXT_INSN (before_case);
5633 end = get_last_insn ();
5634 if (squeeze_notes (&before_case, &end))
5636 reorder_insns (before_case, end,
5637 thiscase->data.case_stmt.start);
5640 end_cleanup_deferral ();
5642 if (thiscase->exit_label && !exit_done)
5643 emit_label (thiscase->exit_label);
5645 POPSTACK (case_stack);
5650 /* Convert the tree NODE into a list linked by the right field, with the left
5651 field zeroed. RIGHT is used for recursion; it is a list to be placed
5652 rightmost in the resulting list. */
5654 static struct case_node *
5655 case_tree2list (struct case_node *node, struct case_node *right)
5657 struct case_node *left;
5660 right = case_tree2list (node->right, right);
5662 node->right = right;
5663 if ((left = node->left))
5666 return case_tree2list (left, node);
5672 /* Generate code to jump to LABEL if OP1 and OP2 are equal. */
5675 do_jump_if_equal (rtx op1, rtx op2, rtx label, int unsignedp)
5677 if (GET_CODE (op1) == CONST_INT && GET_CODE (op2) == CONST_INT)
5683 emit_cmp_and_jump_insns (op1, op2, EQ, NULL_RTX,
5684 (GET_MODE (op1) == VOIDmode
5685 ? GET_MODE (op2) : GET_MODE (op1)),
5689 /* Not all case values are encountered equally. This function
5690 uses a heuristic to weight case labels, in cases where that
5691 looks like a reasonable thing to do.
5693 Right now, all we try to guess is text, and we establish the
5696 chars above space: 16
5705 If we find any cases in the switch that are not either -1 or in the range
5706 of valid ASCII characters, or are control characters other than those
5707 commonly used with "\", don't treat this switch scanning text.
5709 Return 1 if these nodes are suitable for cost estimation, otherwise
5713 estimate_case_costs (case_node_ptr node)
5715 tree min_ascii = integer_minus_one_node;
5716 tree max_ascii = convert (TREE_TYPE (node->high), build_int_2 (127, 0));
5720 /* If we haven't already made the cost table, make it now. Note that the
5721 lower bound of the table is -1, not zero. */
5723 if (! cost_table_initialized)
5725 cost_table_initialized = 1;
5727 for (i = 0; i < 128; i++)
5730 COST_TABLE (i) = 16;
5731 else if (ISPUNCT (i))
5733 else if (ISCNTRL (i))
5734 COST_TABLE (i) = -1;
5737 COST_TABLE (' ') = 8;
5738 COST_TABLE ('\t') = 4;
5739 COST_TABLE ('\0') = 4;
5740 COST_TABLE ('\n') = 2;
5741 COST_TABLE ('\f') = 1;
5742 COST_TABLE ('\v') = 1;
5743 COST_TABLE ('\b') = 1;
5746 /* See if all the case expressions look like text. It is text if the
5747 constant is >= -1 and the highest constant is <= 127. Do all comparisons
5748 as signed arithmetic since we don't want to ever access cost_table with a
5749 value less than -1. Also check that none of the constants in a range
5750 are strange control characters. */
5752 for (n = node; n; n = n->right)
5754 if ((INT_CST_LT (n->low, min_ascii)) || INT_CST_LT (max_ascii, n->high))
5757 for (i = (HOST_WIDE_INT) TREE_INT_CST_LOW (n->low);
5758 i <= (HOST_WIDE_INT) TREE_INT_CST_LOW (n->high); i++)
5759 if (COST_TABLE (i) < 0)
5763 /* All interesting values are within the range of interesting
5764 ASCII characters. */
5768 /* Determine whether two case labels branch to the same target. */
5771 same_case_target_p (rtx l1, rtx l2)
5778 i1 = next_real_insn (l1);
5779 i2 = next_real_insn (l2);
5783 if (i1 && simplejump_p (i1))
5785 l1 = XEXP (SET_SRC (PATTERN (i1)), 0);
5788 if (i2 && simplejump_p (i2))
5790 l2 = XEXP (SET_SRC (PATTERN (i2)), 0);
5795 /* Delete nodes that branch to the default label from a list of
5796 case nodes. Eg. case 5: default: becomes just default: */
5799 strip_default_case_nodes (case_node_ptr *prev, rtx deflab)
5806 if (same_case_target_p (label_rtx (ptr->code_label), deflab))
5813 /* Scan an ordered list of case nodes
5814 combining those with consecutive values or ranges.
5816 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
5819 group_case_nodes (case_node_ptr head)
5821 case_node_ptr node = head;
5825 rtx lab = label_rtx (node->code_label);
5826 case_node_ptr np = node;
5828 /* Try to group the successors of NODE with NODE. */
5829 while (((np = np->right) != 0)
5830 /* Do they jump to the same place? */
5831 && same_case_target_p (label_rtx (np->code_label), lab)
5832 /* Are their ranges consecutive? */
5833 && tree_int_cst_equal (np->low,
5834 fold (build (PLUS_EXPR,
5835 TREE_TYPE (node->high),
5838 /* An overflow is not consecutive. */
5839 && tree_int_cst_lt (node->high,
5840 fold (build (PLUS_EXPR,
5841 TREE_TYPE (node->high),
5843 integer_one_node))))
5845 node->high = np->high;
5847 /* NP is the first node after NODE which can't be grouped with it.
5848 Delete the nodes in between, and move on to that node. */
5854 /* Take an ordered list of case nodes
5855 and transform them into a near optimal binary tree,
5856 on the assumption that any target code selection value is as
5857 likely as any other.
5859 The transformation is performed by splitting the ordered
5860 list into two equal sections plus a pivot. The parts are
5861 then attached to the pivot as left and right branches. Each
5862 branch is then transformed recursively. */
5865 balance_case_nodes (case_node_ptr *head, case_node_ptr parent)
5878 /* Count the number of entries on branch. Also count the ranges. */
5882 if (!tree_int_cst_equal (np->low, np->high))
5886 cost += COST_TABLE (TREE_INT_CST_LOW (np->high));
5890 cost += COST_TABLE (TREE_INT_CST_LOW (np->low));
5898 /* Split this list if it is long enough for that to help. */
5903 /* Find the place in the list that bisects the list's total cost,
5904 Here I gets half the total cost. */
5909 /* Skip nodes while their cost does not reach that amount. */
5910 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
5911 i -= COST_TABLE (TREE_INT_CST_LOW ((*npp)->high));
5912 i -= COST_TABLE (TREE_INT_CST_LOW ((*npp)->low));
5915 npp = &(*npp)->right;
5920 /* Leave this branch lopsided, but optimize left-hand
5921 side and fill in `parent' fields for right-hand side. */
5923 np->parent = parent;
5924 balance_case_nodes (&np->left, np);
5925 for (; np->right; np = np->right)
5926 np->right->parent = np;
5930 /* If there are just three nodes, split at the middle one. */
5932 npp = &(*npp)->right;
5935 /* Find the place in the list that bisects the list's total cost,
5936 where ranges count as 2.
5937 Here I gets half the total cost. */
5938 i = (i + ranges + 1) / 2;
5941 /* Skip nodes while their cost does not reach that amount. */
5942 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
5947 npp = &(*npp)->right;
5952 np->parent = parent;
5955 /* Optimize each of the two split parts. */
5956 balance_case_nodes (&np->left, np);
5957 balance_case_nodes (&np->right, np);
5961 /* Else leave this branch as one level,
5962 but fill in `parent' fields. */
5964 np->parent = parent;
5965 for (; np->right; np = np->right)
5966 np->right->parent = np;
5971 /* Search the parent sections of the case node tree
5972 to see if a test for the lower bound of NODE would be redundant.
5973 INDEX_TYPE is the type of the index expression.
5975 The instructions to generate the case decision tree are
5976 output in the same order as nodes are processed so it is
5977 known that if a parent node checks the range of the current
5978 node minus one that the current node is bounded at its lower
5979 span. Thus the test would be redundant. */
5982 node_has_low_bound (case_node_ptr node, tree index_type)
5985 case_node_ptr pnode;
5987 /* If the lower bound of this node is the lowest value in the index type,
5988 we need not test it. */
5990 if (tree_int_cst_equal (node->low, TYPE_MIN_VALUE (index_type)))
5993 /* If this node has a left branch, the value at the left must be less
5994 than that at this node, so it cannot be bounded at the bottom and
5995 we need not bother testing any further. */
6000 low_minus_one = fold (build (MINUS_EXPR, TREE_TYPE (node->low),
6001 node->low, integer_one_node));
6003 /* If the subtraction above overflowed, we can't verify anything.
6004 Otherwise, look for a parent that tests our value - 1. */
6006 if (! tree_int_cst_lt (low_minus_one, node->low))
6009 for (pnode = node->parent; pnode; pnode = pnode->parent)
6010 if (tree_int_cst_equal (low_minus_one, pnode->high))
6016 /* Search the parent sections of the case node tree
6017 to see if a test for the upper bound of NODE would be redundant.
6018 INDEX_TYPE is the type of the index expression.
6020 The instructions to generate the case decision tree are
6021 output in the same order as nodes are processed so it is
6022 known that if a parent node checks the range of the current
6023 node plus one that the current node is bounded at its upper
6024 span. Thus the test would be redundant. */
6027 node_has_high_bound (case_node_ptr node, tree index_type)
6030 case_node_ptr pnode;
6032 /* If there is no upper bound, obviously no test is needed. */
6034 if (TYPE_MAX_VALUE (index_type) == NULL)
6037 /* If the upper bound of this node is the highest value in the type
6038 of the index expression, we need not test against it. */
6040 if (tree_int_cst_equal (node->high, TYPE_MAX_VALUE (index_type)))
6043 /* If this node has a right branch, the value at the right must be greater
6044 than that at this node, so it cannot be bounded at the top and
6045 we need not bother testing any further. */
6050 high_plus_one = fold (build (PLUS_EXPR, TREE_TYPE (node->high),
6051 node->high, integer_one_node));
6053 /* If the addition above overflowed, we can't verify anything.
6054 Otherwise, look for a parent that tests our value + 1. */
6056 if (! tree_int_cst_lt (node->high, high_plus_one))
6059 for (pnode = node->parent; pnode; pnode = pnode->parent)
6060 if (tree_int_cst_equal (high_plus_one, pnode->low))
6066 /* Search the parent sections of the
6067 case node tree to see if both tests for the upper and lower
6068 bounds of NODE would be redundant. */
6071 node_is_bounded (case_node_ptr node, tree index_type)
6073 return (node_has_low_bound (node, index_type)
6074 && node_has_high_bound (node, index_type));
6077 /* Emit an unconditional jump to LABEL unless it would be dead code. */
6080 emit_jump_if_reachable (rtx label)
6082 if (GET_CODE (get_last_insn ()) != BARRIER)
6086 /* Emit step-by-step code to select a case for the value of INDEX.
6087 The thus generated decision tree follows the form of the
6088 case-node binary tree NODE, whose nodes represent test conditions.
6089 INDEX_TYPE is the type of the index of the switch.
6091 Care is taken to prune redundant tests from the decision tree
6092 by detecting any boundary conditions already checked by
6093 emitted rtx. (See node_has_high_bound, node_has_low_bound
6094 and node_is_bounded, above.)
6096 Where the test conditions can be shown to be redundant we emit
6097 an unconditional jump to the target code. As a further
6098 optimization, the subordinates of a tree node are examined to
6099 check for bounded nodes. In this case conditional and/or
6100 unconditional jumps as a result of the boundary check for the
6101 current node are arranged to target the subordinates associated
6102 code for out of bound conditions on the current node.
6104 We can assume that when control reaches the code generated here,
6105 the index value has already been compared with the parents
6106 of this node, and determined to be on the same side of each parent
6107 as this node is. Thus, if this node tests for the value 51,
6108 and a parent tested for 52, we don't need to consider
6109 the possibility of a value greater than 51. If another parent
6110 tests for the value 50, then this node need not test anything. */
6113 emit_case_nodes (rtx index, case_node_ptr node, rtx default_label,
6116 /* If INDEX has an unsigned type, we must make unsigned branches. */
6117 int unsignedp = TREE_UNSIGNED (index_type);
6118 enum machine_mode mode = GET_MODE (index);
6119 enum machine_mode imode = TYPE_MODE (index_type);
6121 /* See if our parents have already tested everything for us.
6122 If they have, emit an unconditional jump for this node. */
6123 if (node_is_bounded (node, index_type))
6124 emit_jump (label_rtx (node->code_label));
6126 else if (tree_int_cst_equal (node->low, node->high))
6128 /* Node is single valued. First see if the index expression matches
6129 this node and then check our children, if any. */
6131 do_jump_if_equal (index,
6132 convert_modes (mode, imode,
6133 expand_expr (node->low, NULL_RTX,
6136 label_rtx (node->code_label), unsignedp);
6138 if (node->right != 0 && node->left != 0)
6140 /* This node has children on both sides.
6141 Dispatch to one side or the other
6142 by comparing the index value with this node's value.
6143 If one subtree is bounded, check that one first,
6144 so we can avoid real branches in the tree. */
6146 if (node_is_bounded (node->right, index_type))
6148 emit_cmp_and_jump_insns (index,
6151 expand_expr (node->high, NULL_RTX,
6154 GT, NULL_RTX, mode, unsignedp,
6155 label_rtx (node->right->code_label));
6156 emit_case_nodes (index, node->left, default_label, index_type);
6159 else if (node_is_bounded (node->left, index_type))
6161 emit_cmp_and_jump_insns (index,
6164 expand_expr (node->high, NULL_RTX,
6167 LT, NULL_RTX, mode, unsignedp,
6168 label_rtx (node->left->code_label));
6169 emit_case_nodes (index, node->right, default_label, index_type);
6174 /* Neither node is bounded. First distinguish the two sides;
6175 then emit the code for one side at a time. */
6177 tree test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
6179 /* See if the value is on the right. */
6180 emit_cmp_and_jump_insns (index,
6183 expand_expr (node->high, NULL_RTX,
6186 GT, NULL_RTX, mode, unsignedp,
6187 label_rtx (test_label));
6189 /* Value must be on the left.
6190 Handle the left-hand subtree. */
6191 emit_case_nodes (index, node->left, default_label, index_type);
6192 /* If left-hand subtree does nothing,
6194 emit_jump_if_reachable (default_label);
6196 /* Code branches here for the right-hand subtree. */
6197 expand_label (test_label);
6198 emit_case_nodes (index, node->right, default_label, index_type);
6202 else if (node->right != 0 && node->left == 0)
6204 /* Here we have a right child but no left so we issue conditional
6205 branch to default and process the right child.
6207 Omit the conditional branch to default if we it avoid only one
6208 right child; it costs too much space to save so little time. */
6210 if (node->right->right || node->right->left
6211 || !tree_int_cst_equal (node->right->low, node->right->high))
6213 if (!node_has_low_bound (node, index_type))
6215 emit_cmp_and_jump_insns (index,
6218 expand_expr (node->high, NULL_RTX,
6221 LT, NULL_RTX, mode, unsignedp,
6225 emit_case_nodes (index, node->right, default_label, index_type);
6228 /* We cannot process node->right normally
6229 since we haven't ruled out the numbers less than
6230 this node's value. So handle node->right explicitly. */
6231 do_jump_if_equal (index,
6234 expand_expr (node->right->low, NULL_RTX,
6237 label_rtx (node->right->code_label), unsignedp);
6240 else if (node->right == 0 && node->left != 0)
6242 /* Just one subtree, on the left. */
6243 if (node->left->left || node->left->right
6244 || !tree_int_cst_equal (node->left->low, node->left->high))
6246 if (!node_has_high_bound (node, index_type))
6248 emit_cmp_and_jump_insns (index,
6251 expand_expr (node->high, NULL_RTX,
6254 GT, NULL_RTX, mode, unsignedp,
6258 emit_case_nodes (index, node->left, default_label, index_type);
6261 /* We cannot process node->left normally
6262 since we haven't ruled out the numbers less than
6263 this node's value. So handle node->left explicitly. */
6264 do_jump_if_equal (index,
6267 expand_expr (node->left->low, NULL_RTX,
6270 label_rtx (node->left->code_label), unsignedp);
6275 /* Node is a range. These cases are very similar to those for a single
6276 value, except that we do not start by testing whether this node
6277 is the one to branch to. */
6279 if (node->right != 0 && node->left != 0)
6281 /* Node has subtrees on both sides.
6282 If the right-hand subtree is bounded,
6283 test for it first, since we can go straight there.
6284 Otherwise, we need to make a branch in the control structure,
6285 then handle the two subtrees. */
6286 tree test_label = 0;
6288 if (node_is_bounded (node->right, index_type))
6289 /* Right hand node is fully bounded so we can eliminate any
6290 testing and branch directly to the target code. */
6291 emit_cmp_and_jump_insns (index,
6294 expand_expr (node->high, NULL_RTX,
6297 GT, NULL_RTX, mode, unsignedp,
6298 label_rtx (node->right->code_label));
6301 /* Right hand node requires testing.
6302 Branch to a label where we will handle it later. */
6304 test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
6305 emit_cmp_and_jump_insns (index,
6308 expand_expr (node->high, NULL_RTX,
6311 GT, NULL_RTX, mode, unsignedp,
6312 label_rtx (test_label));
6315 /* Value belongs to this node or to the left-hand subtree. */
6317 emit_cmp_and_jump_insns (index,
6320 expand_expr (node->low, NULL_RTX,
6323 GE, NULL_RTX, mode, unsignedp,
6324 label_rtx (node->code_label));
6326 /* Handle the left-hand subtree. */
6327 emit_case_nodes (index, node->left, default_label, index_type);
6329 /* If right node had to be handled later, do that now. */
6333 /* If the left-hand subtree fell through,
6334 don't let it fall into the right-hand subtree. */
6335 emit_jump_if_reachable (default_label);
6337 expand_label (test_label);
6338 emit_case_nodes (index, node->right, default_label, index_type);
6342 else if (node->right != 0 && node->left == 0)
6344 /* Deal with values to the left of this node,
6345 if they are possible. */
6346 if (!node_has_low_bound (node, index_type))
6348 emit_cmp_and_jump_insns (index,
6351 expand_expr (node->low, NULL_RTX,
6354 LT, NULL_RTX, mode, unsignedp,
6358 /* Value belongs to this node or to the right-hand subtree. */
6360 emit_cmp_and_jump_insns (index,
6363 expand_expr (node->high, NULL_RTX,
6366 LE, NULL_RTX, mode, unsignedp,
6367 label_rtx (node->code_label));
6369 emit_case_nodes (index, node->right, default_label, index_type);
6372 else if (node->right == 0 && node->left != 0)
6374 /* Deal with values to the right of this node,
6375 if they are possible. */
6376 if (!node_has_high_bound (node, index_type))
6378 emit_cmp_and_jump_insns (index,
6381 expand_expr (node->high, NULL_RTX,
6384 GT, NULL_RTX, mode, unsignedp,
6388 /* Value belongs to this node or to the left-hand subtree. */
6390 emit_cmp_and_jump_insns (index,
6393 expand_expr (node->low, NULL_RTX,
6396 GE, NULL_RTX, mode, unsignedp,
6397 label_rtx (node->code_label));
6399 emit_case_nodes (index, node->left, default_label, index_type);
6404 /* Node has no children so we check low and high bounds to remove
6405 redundant tests. Only one of the bounds can exist,
6406 since otherwise this node is bounded--a case tested already. */
6407 int high_bound = node_has_high_bound (node, index_type);
6408 int low_bound = node_has_low_bound (node, index_type);
6410 if (!high_bound && low_bound)
6412 emit_cmp_and_jump_insns (index,
6415 expand_expr (node->high, NULL_RTX,
6418 GT, NULL_RTX, mode, unsignedp,
6422 else if (!low_bound && high_bound)
6424 emit_cmp_and_jump_insns (index,
6427 expand_expr (node->low, NULL_RTX,
6430 LT, NULL_RTX, mode, unsignedp,
6433 else if (!low_bound && !high_bound)
6435 /* Widen LOW and HIGH to the same width as INDEX. */
6436 tree type = (*lang_hooks.types.type_for_mode) (mode, unsignedp);
6437 tree low = build1 (CONVERT_EXPR, type, node->low);
6438 tree high = build1 (CONVERT_EXPR, type, node->high);
6439 rtx low_rtx, new_index, new_bound;
6441 /* Instead of doing two branches, emit one unsigned branch for
6442 (index-low) > (high-low). */
6443 low_rtx = expand_expr (low, NULL_RTX, mode, 0);
6444 new_index = expand_simple_binop (mode, MINUS, index, low_rtx,
6445 NULL_RTX, unsignedp,
6447 new_bound = expand_expr (fold (build (MINUS_EXPR, type,
6451 emit_cmp_and_jump_insns (new_index, new_bound, GT, NULL_RTX,
6452 mode, 1, default_label);
6455 emit_jump (label_rtx (node->code_label));
6460 #include "gt-stmt.h"