1 /* Expands front end tree to back end RTL for GNU C-Compiler
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"
61 /* Assume that case vectors are not pc-relative. */
62 #ifndef CASE_VECTOR_PC_RELATIVE
63 #define CASE_VECTOR_PC_RELATIVE 0
66 /* Functions and data structures for expanding case statements. */
68 /* Case label structure, used to hold info on labels within case
69 statements. We handle "range" labels; for a single-value label
70 as in C, the high and low limits are the same.
72 An AVL tree of case nodes is initially created, and later transformed
73 to a list linked via the RIGHT fields in the nodes. Nodes with
74 higher case values are later in the list.
76 Switch statements can be output in one of two forms. A branch table
77 is used if there are more than a few labels and the labels are dense
78 within the range between the smallest and largest case value. If a
79 branch table is used, no further manipulations are done with the case
82 The alternative to the use of a branch table is to generate a series
83 of compare and jump insns. When that is done, we use the LEFT, RIGHT,
84 and PARENT fields to hold a binary tree. Initially the tree is
85 totally unbalanced, with everything on the right. We balance the tree
86 with nodes on the left having lower case values than the parent
87 and nodes on the right having higher values. We then output the tree
90 struct case_node GTY(())
92 struct case_node *left; /* Left son in binary tree */
93 struct case_node *right; /* Right son in binary tree; also node chain */
94 struct case_node *parent; /* Parent of node in binary tree */
95 tree low; /* Lowest index value for this label */
96 tree high; /* Highest index value for this label */
97 tree code_label; /* Label to jump to when node matches */
101 typedef struct case_node case_node;
102 typedef struct case_node *case_node_ptr;
104 /* These are used by estimate_case_costs and balance_case_nodes. */
106 /* This must be a signed type, and non-ANSI compilers lack signed char. */
107 static short cost_table_[129];
108 static int use_cost_table;
109 static int cost_table_initialized;
111 /* Special care is needed because we allow -1, but TREE_INT_CST_LOW
113 #define COST_TABLE(I) cost_table_[(unsigned HOST_WIDE_INT) ((I) + 1)]
115 /* Stack of control and binding constructs we are currently inside.
117 These constructs begin when you call `expand_start_WHATEVER'
118 and end when you call `expand_end_WHATEVER'. This stack records
119 info about how the construct began that tells the end-function
120 what to do. It also may provide information about the construct
121 to alter the behavior of other constructs within the body.
122 For example, they may affect the behavior of C `break' and `continue'.
124 Each construct gets one `struct nesting' object.
125 All of these objects are chained through the `all' field.
126 `nesting_stack' points to the first object (innermost construct).
127 The position of an entry on `nesting_stack' is in its `depth' field.
129 Each type of construct has its own individual stack.
130 For example, loops have `loop_stack'. Each object points to the
131 next object of the same type through the `next' field.
133 Some constructs are visible to `break' exit-statements and others
134 are not. Which constructs are visible depends on the language.
135 Therefore, the data structure allows each construct to be visible
136 or not, according to the args given when the construct is started.
137 The construct is visible if the `exit_label' field is non-null.
138 In that case, the value should be a CODE_LABEL rtx. */
140 struct nesting GTY(())
143 struct nesting *next;
154 /* For conds (if-then and if-then-else statements). */
157 /* Label for the end of the if construct.
158 There is none if EXITFLAG was not set
159 and no `else' has been seen yet. */
161 /* Label for the end of this alternative.
162 This may be the end of the if or the next else/elseif. */
164 } GTY ((tag ("COND_NESTING"))) cond;
168 /* Label at the top of the loop; place to loop back to. */
170 /* Label at the end of the whole construct. */
172 /* Label for `continue' statement to jump to;
173 this is in front of the stepper of the loop. */
175 } GTY ((tag ("LOOP_NESTING"))) loop;
176 /* For variable binding contours. */
179 /* Sequence number of this binding contour within the function,
180 in order of entry. */
181 int block_start_count;
182 /* Nonzero => value to restore stack to on exit. */
184 /* The NOTE that starts this contour.
185 Used by expand_goto to check whether the destination
186 is within each contour or not. */
188 /* Innermost containing binding contour that has a stack level. */
189 struct nesting *innermost_stack_block;
190 /* List of cleanups to be run on exit from this contour.
191 This is a list of expressions to be evaluated.
192 The TREE_PURPOSE of each link is the ..._DECL node
193 which the cleanup pertains to. */
195 /* List of cleanup-lists of blocks containing this block,
196 as they were at the locus where this block appears.
197 There is an element for each containing block,
198 ordered innermost containing block first.
199 The tail of this list can be 0,
200 if all remaining elements would be empty lists.
201 The element's TREE_VALUE is the cleanup-list of that block,
202 which may be null. */
204 /* Chain of labels defined inside this binding contour.
205 For contours that have stack levels or cleanups. */
206 struct label_chain *label_chain;
207 /* Number of function calls seen, as of start of this block. */
208 int n_function_calls;
209 /* Nonzero if this is associated with an EH region. */
210 int exception_region;
211 /* The saved target_temp_slot_level from our outer block.
212 We may reset target_temp_slot_level to be the level of
213 this block, if that is done, target_temp_slot_level
214 reverts to the saved target_temp_slot_level at the very
216 int block_target_temp_slot_level;
217 /* True if we are currently emitting insns in an area of
218 output code that is controlled by a conditional
219 expression. This is used by the cleanup handling code to
220 generate conditional cleanup actions. */
221 int conditional_code;
222 /* A place to move the start of the exception region for any
223 of the conditional cleanups, must be at the end or after
224 the start of the last unconditional cleanup, and before any
225 conditional branch points. */
226 rtx last_unconditional_cleanup;
227 } GTY ((tag ("BLOCK_NESTING"))) block;
228 /* For switch (C) or case (Pascal) statements,
229 and also for dummies (see `expand_start_case_dummy'). */
232 /* The insn after which the case dispatch should finally
233 be emitted. Zero for a dummy. */
235 /* A list of case labels; it is first built as an AVL tree.
236 During expand_end_case, this is converted to a list, and may be
237 rearranged into a nearly balanced binary tree. */
238 struct case_node *case_list;
239 /* Label to jump to if no case matches. */
241 /* The expression to be dispatched on. */
243 /* Type that INDEX_EXPR should be converted to. */
245 /* Name of this kind of statement, for warnings. */
246 const char *printname;
247 /* Used to save no_line_numbers till we see the first case label.
248 We set this to -1 when we see the first case label in this
250 int line_number_status;
251 } GTY ((tag ("CASE_NESTING"))) case_stmt;
252 } GTY ((desc ("%1.desc"))) data;
255 /* Allocate and return a new `struct nesting'. */
257 #define ALLOC_NESTING() \
258 (struct nesting *) ggc_alloc (sizeof (struct nesting))
260 /* Pop the nesting stack element by element until we pop off
261 the element which is at the top of STACK.
262 Update all the other stacks, popping off elements from them
263 as we pop them from nesting_stack. */
265 #define POPSTACK(STACK) \
266 do { struct nesting *target = STACK; \
267 struct nesting *this; \
268 do { this = nesting_stack; \
269 if (loop_stack == this) \
270 loop_stack = loop_stack->next; \
271 if (cond_stack == this) \
272 cond_stack = cond_stack->next; \
273 if (block_stack == this) \
274 block_stack = block_stack->next; \
275 if (stack_block_stack == this) \
276 stack_block_stack = stack_block_stack->next; \
277 if (case_stack == this) \
278 case_stack = case_stack->next; \
279 nesting_depth = nesting_stack->depth - 1; \
280 nesting_stack = this->all; } \
281 while (this != target); } while (0)
283 /* In some cases it is impossible to generate code for a forward goto
284 until the label definition is seen. This happens when it may be necessary
285 for the goto to reset the stack pointer: we don't yet know how to do that.
286 So expand_goto puts an entry on this fixup list.
287 Each time a binding contour that resets the stack is exited,
289 If the target label has now been defined, we can insert the proper code. */
291 struct goto_fixup GTY(())
293 /* Points to following fixup. */
294 struct goto_fixup *next;
295 /* Points to the insn before the jump insn.
296 If more code must be inserted, it goes after this insn. */
298 /* The LABEL_DECL that this jump is jumping to, or 0
299 for break, continue or return. */
301 /* The BLOCK for the place where this goto was found. */
303 /* The CODE_LABEL rtx that this is jumping to. */
305 /* Number of binding contours started in current function
306 before the label reference. */
307 int block_start_count;
308 /* The outermost stack level that should be restored for this jump.
309 Each time a binding contour that resets the stack is exited,
310 if the target label is *not* yet defined, this slot is updated. */
312 /* List of lists of cleanup expressions to be run by this goto.
313 There is one element for each block that this goto is within.
314 The tail of this list can be 0,
315 if all remaining elements would be empty.
316 The TREE_VALUE contains the cleanup list of that block as of the
317 time this goto was seen.
318 The TREE_ADDRESSABLE flag is 1 for a block that has been exited. */
319 tree cleanup_list_list;
322 /* Within any binding contour that must restore a stack level,
323 all labels are recorded with a chain of these structures. */
325 struct label_chain GTY(())
327 /* Points to following fixup. */
328 struct label_chain *next;
332 struct stmt_status GTY(())
334 /* Chain of all pending binding contours. */
335 struct nesting * x_block_stack;
337 /* If any new stacks are added here, add them to POPSTACKS too. */
339 /* Chain of all pending binding contours that restore stack levels
341 struct nesting * x_stack_block_stack;
343 /* Chain of all pending conditional statements. */
344 struct nesting * x_cond_stack;
346 /* Chain of all pending loops. */
347 struct nesting * x_loop_stack;
349 /* Chain of all pending case or switch statements. */
350 struct nesting * x_case_stack;
352 /* Separate chain including all of the above,
353 chained through the `all' field. */
354 struct nesting * x_nesting_stack;
356 /* Number of entries on nesting_stack now. */
359 /* Number of binding contours started so far in this function. */
360 int x_block_start_count;
362 /* Each time we expand an expression-statement,
363 record the expr's type and its RTL value here. */
364 tree x_last_expr_type;
365 rtx x_last_expr_value;
367 /* Nonzero if within a ({...}) grouping, in which case we must
368 always compute a value for each expr-stmt in case it is the last one. */
369 int x_expr_stmts_for_value;
371 /* Filename and line number of last line-number note,
372 whether we actually emitted it or not. */
373 const char *x_emit_filename;
376 struct goto_fixup *x_goto_fixup_chain;
379 #define block_stack (cfun->stmt->x_block_stack)
380 #define stack_block_stack (cfun->stmt->x_stack_block_stack)
381 #define cond_stack (cfun->stmt->x_cond_stack)
382 #define loop_stack (cfun->stmt->x_loop_stack)
383 #define case_stack (cfun->stmt->x_case_stack)
384 #define nesting_stack (cfun->stmt->x_nesting_stack)
385 #define nesting_depth (cfun->stmt->x_nesting_depth)
386 #define current_block_start_count (cfun->stmt->x_block_start_count)
387 #define last_expr_type (cfun->stmt->x_last_expr_type)
388 #define last_expr_value (cfun->stmt->x_last_expr_value)
389 #define expr_stmts_for_value (cfun->stmt->x_expr_stmts_for_value)
390 #define emit_filename (cfun->stmt->x_emit_filename)
391 #define emit_lineno (cfun->stmt->x_emit_lineno)
392 #define goto_fixup_chain (cfun->stmt->x_goto_fixup_chain)
394 /* Nonzero if we are using EH to handle cleanups. */
395 static int using_eh_for_cleanups_p = 0;
397 static int n_occurrences PARAMS ((int, const char *));
398 static bool parse_input_constraint PARAMS ((const char **, int, int, int,
399 int, const char * const *,
401 static bool decl_conflicts_with_clobbers_p PARAMS ((tree, const HARD_REG_SET));
402 static void expand_goto_internal PARAMS ((tree, rtx, rtx));
403 static int expand_fixup PARAMS ((tree, rtx, rtx));
404 static rtx expand_nl_handler_label PARAMS ((rtx, rtx));
405 static void expand_nl_goto_receiver PARAMS ((void));
406 static void expand_nl_goto_receivers PARAMS ((struct nesting *));
407 static void fixup_gotos PARAMS ((struct nesting *, rtx, tree,
409 static bool check_operand_nalternatives PARAMS ((tree, tree));
410 static bool check_unique_operand_names PARAMS ((tree, tree));
411 static tree resolve_operand_names PARAMS ((tree, tree, tree,
413 static char *resolve_operand_name_1 PARAMS ((char *, tree, tree));
414 static void expand_null_return_1 PARAMS ((rtx));
415 static enum br_predictor return_prediction PARAMS ((rtx));
416 static void expand_value_return PARAMS ((rtx));
417 static int tail_recursion_args PARAMS ((tree, tree));
418 static void expand_cleanups PARAMS ((tree, tree, int, int));
419 static void check_seenlabel PARAMS ((void));
420 static void do_jump_if_equal PARAMS ((rtx, rtx, rtx, int));
421 static int estimate_case_costs PARAMS ((case_node_ptr));
422 static bool same_case_target_p PARAMS ((rtx, rtx));
423 static void strip_default_case_nodes PARAMS ((case_node_ptr *, rtx));
424 static bool lshift_cheap_p PARAMS ((void));
425 static int case_bit_test_cmp PARAMS ((const void *, const void *));
426 static void emit_case_bit_tests PARAMS ((tree, tree, tree, tree,
427 case_node_ptr, rtx));
428 static void group_case_nodes PARAMS ((case_node_ptr));
429 static void balance_case_nodes PARAMS ((case_node_ptr *,
431 static int node_has_low_bound PARAMS ((case_node_ptr, tree));
432 static int node_has_high_bound PARAMS ((case_node_ptr, tree));
433 static int node_is_bounded PARAMS ((case_node_ptr, tree));
434 static void emit_jump_if_reachable PARAMS ((rtx));
435 static void emit_case_nodes PARAMS ((rtx, case_node_ptr, rtx, tree));
436 static struct case_node *case_tree2list PARAMS ((case_node *, case_node *));
439 using_eh_for_cleanups ()
441 using_eh_for_cleanups_p = 1;
445 init_stmt_for_function ()
447 cfun->stmt = ((struct stmt_status *)ggc_alloc (sizeof (struct stmt_status)));
449 /* We are not currently within any block, conditional, loop or case. */
451 stack_block_stack = 0;
458 current_block_start_count = 0;
460 /* No gotos have been expanded yet. */
461 goto_fixup_chain = 0;
463 /* We are not processing a ({...}) grouping. */
464 expr_stmts_for_value = 0;
468 /* Record the current file and line. Called from emit_line_note. */
470 set_file_and_line_for_stmt (file, line)
474 /* If we're outputting an inline function, and we add a line note,
475 there may be no CFUN->STMT information. So, there's no need to
479 emit_filename = file;
484 /* Emit a no-op instruction. */
491 last_insn = get_last_insn ();
493 && (GET_CODE (last_insn) == CODE_LABEL
494 || (GET_CODE (last_insn) == NOTE
495 && prev_real_insn (last_insn) == 0)))
496 emit_insn (gen_nop ());
499 /* Return the rtx-label that corresponds to a LABEL_DECL,
500 creating it if necessary. */
506 if (TREE_CODE (label) != LABEL_DECL)
509 if (!DECL_RTL_SET_P (label))
510 SET_DECL_RTL (label, gen_label_rtx ());
512 return DECL_RTL (label);
516 /* Add an unconditional jump to LABEL as the next sequential instruction. */
522 do_pending_stack_adjust ();
523 emit_jump_insn (gen_jump (label));
527 /* Emit code to jump to the address
528 specified by the pointer expression EXP. */
531 expand_computed_goto (exp)
534 rtx x = expand_expr (exp, NULL_RTX, VOIDmode, 0);
536 #ifdef POINTERS_EXTEND_UNSIGNED
537 if (GET_MODE (x) != Pmode)
538 x = convert_memory_address (Pmode, x);
543 if (! cfun->computed_goto_common_label)
545 cfun->computed_goto_common_reg = copy_to_mode_reg (Pmode, x);
546 cfun->computed_goto_common_label = gen_label_rtx ();
547 emit_label (cfun->computed_goto_common_label);
549 do_pending_stack_adjust ();
550 emit_indirect_jump (cfun->computed_goto_common_reg);
552 current_function_has_computed_jump = 1;
556 emit_move_insn (cfun->computed_goto_common_reg, x);
557 emit_jump (cfun->computed_goto_common_label);
561 /* Handle goto statements and the labels that they can go to. */
563 /* Specify the location in the RTL code of a label LABEL,
564 which is a LABEL_DECL tree node.
566 This is used for the kind of label that the user can jump to with a
567 goto statement, and for alternatives of a switch or case statement.
568 RTL labels generated for loops and conditionals don't go through here;
569 they are generated directly at the RTL level, by other functions below.
571 Note that this has nothing to do with defining label *names*.
572 Languages vary in how they do that and what that even means. */
578 struct label_chain *p;
580 do_pending_stack_adjust ();
581 emit_label (label_rtx (label));
582 if (DECL_NAME (label))
583 LABEL_NAME (DECL_RTL (label)) = IDENTIFIER_POINTER (DECL_NAME (label));
585 if (stack_block_stack != 0)
587 p = (struct label_chain *) ggc_alloc (sizeof (struct label_chain));
588 p->next = stack_block_stack->data.block.label_chain;
589 stack_block_stack->data.block.label_chain = p;
594 /* Declare that LABEL (a LABEL_DECL) may be used for nonlocal gotos
595 from nested functions. */
598 declare_nonlocal_label (label)
601 rtx slot = assign_stack_local (Pmode, GET_MODE_SIZE (Pmode), 0);
603 nonlocal_labels = tree_cons (NULL_TREE, label, nonlocal_labels);
604 LABEL_PRESERVE_P (label_rtx (label)) = 1;
605 if (nonlocal_goto_handler_slots == 0)
607 emit_stack_save (SAVE_NONLOCAL,
608 &nonlocal_goto_stack_level,
609 PREV_INSN (tail_recursion_reentry));
611 nonlocal_goto_handler_slots
612 = gen_rtx_EXPR_LIST (VOIDmode, slot, nonlocal_goto_handler_slots);
615 /* Generate RTL code for a `goto' statement with target label LABEL.
616 LABEL should be a LABEL_DECL tree node that was or will later be
617 defined with `expand_label'. */
625 /* Check for a nonlocal goto to a containing function. */
626 context = decl_function_context (label);
627 if (context != 0 && context != current_function_decl)
629 struct function *p = find_function_data (context);
630 rtx label_ref = gen_rtx_LABEL_REF (Pmode, label_rtx (label));
631 rtx handler_slot, static_chain, save_area, insn;
634 /* Find the corresponding handler slot for this label. */
635 handler_slot = p->x_nonlocal_goto_handler_slots;
636 for (link = p->x_nonlocal_labels; TREE_VALUE (link) != label;
637 link = TREE_CHAIN (link))
638 handler_slot = XEXP (handler_slot, 1);
639 handler_slot = XEXP (handler_slot, 0);
641 p->has_nonlocal_label = 1;
642 current_function_has_nonlocal_goto = 1;
643 LABEL_REF_NONLOCAL_P (label_ref) = 1;
645 /* Copy the rtl for the slots so that they won't be shared in
646 case the virtual stack vars register gets instantiated differently
647 in the parent than in the child. */
649 static_chain = copy_to_reg (lookup_static_chain (label));
651 /* Get addr of containing function's current nonlocal goto handler,
652 which will do any cleanups and then jump to the label. */
653 handler_slot = copy_to_reg (replace_rtx (copy_rtx (handler_slot),
654 virtual_stack_vars_rtx,
657 /* Get addr of containing function's nonlocal save area. */
658 save_area = p->x_nonlocal_goto_stack_level;
660 save_area = replace_rtx (copy_rtx (save_area),
661 virtual_stack_vars_rtx, static_chain);
663 #if HAVE_nonlocal_goto
664 if (HAVE_nonlocal_goto)
665 emit_insn (gen_nonlocal_goto (static_chain, handler_slot,
666 save_area, label_ref));
670 /* Restore frame pointer for containing function.
671 This sets the actual hard register used for the frame pointer
672 to the location of the function's incoming static chain info.
673 The non-local goto handler will then adjust it to contain the
674 proper value and reload the argument pointer, if needed. */
675 emit_move_insn (hard_frame_pointer_rtx, static_chain);
676 emit_stack_restore (SAVE_NONLOCAL, save_area, NULL_RTX);
678 /* USE of hard_frame_pointer_rtx added for consistency;
679 not clear if really needed. */
680 emit_insn (gen_rtx_USE (VOIDmode, hard_frame_pointer_rtx));
681 emit_insn (gen_rtx_USE (VOIDmode, stack_pointer_rtx));
682 emit_indirect_jump (handler_slot);
685 /* Search backwards to the jump insn and mark it as a
687 for (insn = get_last_insn (); insn; insn = PREV_INSN (insn))
689 if (GET_CODE (insn) == JUMP_INSN)
691 REG_NOTES (insn) = alloc_EXPR_LIST (REG_NON_LOCAL_GOTO,
692 const0_rtx, REG_NOTES (insn));
695 else if (GET_CODE (insn) == CALL_INSN)
700 expand_goto_internal (label, label_rtx (label), NULL_RTX);
703 /* Generate RTL code for a `goto' statement with target label BODY.
704 LABEL should be a LABEL_REF.
705 LAST_INSN, if non-0, is the rtx we should consider as the last
706 insn emitted (for the purposes of cleaning up a return). */
709 expand_goto_internal (body, label, last_insn)
714 struct nesting *block;
717 if (GET_CODE (label) != CODE_LABEL)
720 /* If label has already been defined, we can tell now
721 whether and how we must alter the stack level. */
723 if (PREV_INSN (label) != 0)
725 /* Find the innermost pending block that contains the label.
726 (Check containment by comparing insn-uids.)
727 Then restore the outermost stack level within that block,
728 and do cleanups of all blocks contained in it. */
729 for (block = block_stack; block; block = block->next)
731 if (INSN_UID (block->data.block.first_insn) < INSN_UID (label))
733 if (block->data.block.stack_level != 0)
734 stack_level = block->data.block.stack_level;
735 /* Execute the cleanups for blocks we are exiting. */
736 if (block->data.block.cleanups != 0)
738 expand_cleanups (block->data.block.cleanups, NULL_TREE, 1, 1);
739 do_pending_stack_adjust ();
745 /* Ensure stack adjust isn't done by emit_jump, as this
746 would clobber the stack pointer. This one should be
747 deleted as dead by flow. */
748 clear_pending_stack_adjust ();
749 do_pending_stack_adjust ();
751 /* Don't do this adjust if it's to the end label and this function
752 is to return with a depressed stack pointer. */
753 if (label == return_label
754 && (((TREE_CODE (TREE_TYPE (current_function_decl))
756 && (TYPE_RETURNS_STACK_DEPRESSED
757 (TREE_TYPE (current_function_decl))))))
760 emit_stack_restore (SAVE_BLOCK, stack_level, NULL_RTX);
763 if (body != 0 && DECL_TOO_LATE (body))
764 error ("jump to `%s' invalidly jumps into binding contour",
765 IDENTIFIER_POINTER (DECL_NAME (body)));
767 /* Label not yet defined: may need to put this goto
768 on the fixup list. */
769 else if (! expand_fixup (body, label, last_insn))
771 /* No fixup needed. Record that the label is the target
772 of at least one goto that has no fixup. */
774 TREE_ADDRESSABLE (body) = 1;
780 /* Generate if necessary a fixup for a goto
781 whose target label in tree structure (if any) is TREE_LABEL
782 and whose target in rtl is RTL_LABEL.
784 If LAST_INSN is nonzero, we pretend that the jump appears
785 after insn LAST_INSN instead of at the current point in the insn stream.
787 The fixup will be used later to insert insns just before the goto.
788 Those insns will restore the stack level as appropriate for the
789 target label, and will (in the case of C++) also invoke any object
790 destructors which have to be invoked when we exit the scopes which
791 are exited by the goto.
793 Value is nonzero if a fixup is made. */
796 expand_fixup (tree_label, rtl_label, last_insn)
801 struct nesting *block, *end_block;
803 /* See if we can recognize which block the label will be output in.
804 This is possible in some very common cases.
805 If we succeed, set END_BLOCK to that block.
806 Otherwise, set it to 0. */
809 && (rtl_label == cond_stack->data.cond.endif_label
810 || rtl_label == cond_stack->data.cond.next_label))
811 end_block = cond_stack;
812 /* If we are in a loop, recognize certain labels which
813 are likely targets. This reduces the number of fixups
814 we need to create. */
816 && (rtl_label == loop_stack->data.loop.start_label
817 || rtl_label == loop_stack->data.loop.end_label
818 || rtl_label == loop_stack->data.loop.continue_label))
819 end_block = loop_stack;
823 /* Now set END_BLOCK to the binding level to which we will return. */
827 struct nesting *next_block = end_block->all;
830 /* First see if the END_BLOCK is inside the innermost binding level.
831 If so, then no cleanups or stack levels are relevant. */
832 while (next_block && next_block != block)
833 next_block = next_block->all;
838 /* Otherwise, set END_BLOCK to the innermost binding level
839 which is outside the relevant control-structure nesting. */
840 next_block = block_stack->next;
841 for (block = block_stack; block != end_block; block = block->all)
842 if (block == next_block)
843 next_block = next_block->next;
844 end_block = next_block;
847 /* Does any containing block have a stack level or cleanups?
848 If not, no fixup is needed, and that is the normal case
849 (the only case, for standard C). */
850 for (block = block_stack; block != end_block; block = block->next)
851 if (block->data.block.stack_level != 0
852 || block->data.block.cleanups != 0)
855 if (block != end_block)
857 /* Ok, a fixup is needed. Add a fixup to the list of such. */
858 struct goto_fixup *fixup
859 = (struct goto_fixup *) ggc_alloc (sizeof (struct goto_fixup));
860 /* In case an old stack level is restored, make sure that comes
861 after any pending stack adjust. */
862 /* ?? If the fixup isn't to come at the present position,
863 doing the stack adjust here isn't useful. Doing it with our
864 settings at that location isn't useful either. Let's hope
867 do_pending_stack_adjust ();
868 fixup->target = tree_label;
869 fixup->target_rtl = rtl_label;
871 /* Create a BLOCK node and a corresponding matched set of
872 NOTE_INSN_BLOCK_BEG and NOTE_INSN_BLOCK_END notes at
873 this point. The notes will encapsulate any and all fixup
874 code which we might later insert at this point in the insn
875 stream. Also, the BLOCK node will be the parent (i.e. the
876 `SUPERBLOCK') of any other BLOCK nodes which we might create
877 later on when we are expanding the fixup code.
879 Note that optimization passes (including expand_end_loop)
880 might move the *_BLOCK notes away, so we use a NOTE_INSN_DELETED
884 rtx original_before_jump
885 = last_insn ? last_insn : get_last_insn ();
890 block = make_node (BLOCK);
891 TREE_USED (block) = 1;
893 if (!cfun->x_whole_function_mode_p)
894 (*lang_hooks.decls.insert_block) (block);
898 = BLOCK_CHAIN (DECL_INITIAL (current_function_decl));
899 BLOCK_CHAIN (DECL_INITIAL (current_function_decl))
904 start = emit_note (NULL, NOTE_INSN_BLOCK_BEG);
905 if (cfun->x_whole_function_mode_p)
906 NOTE_BLOCK (start) = block;
907 fixup->before_jump = emit_note (NULL, NOTE_INSN_DELETED);
908 end = emit_note (NULL, NOTE_INSN_BLOCK_END);
909 if (cfun->x_whole_function_mode_p)
910 NOTE_BLOCK (end) = block;
911 fixup->context = block;
913 emit_insn_after (start, original_before_jump);
916 fixup->block_start_count = current_block_start_count;
917 fixup->stack_level = 0;
918 fixup->cleanup_list_list
919 = ((block->data.block.outer_cleanups
920 || block->data.block.cleanups)
921 ? tree_cons (NULL_TREE, block->data.block.cleanups,
922 block->data.block.outer_cleanups)
924 fixup->next = goto_fixup_chain;
925 goto_fixup_chain = fixup;
931 /* Expand any needed fixups in the outputmost binding level of the
932 function. FIRST_INSN is the first insn in the function. */
935 expand_fixups (first_insn)
938 fixup_gotos (NULL, NULL_RTX, NULL_TREE, first_insn, 0);
941 /* When exiting a binding contour, process all pending gotos requiring fixups.
942 THISBLOCK is the structure that describes the block being exited.
943 STACK_LEVEL is the rtx for the stack level to restore exiting this contour.
944 CLEANUP_LIST is a list of expressions to evaluate on exiting this contour.
945 FIRST_INSN is the insn that began this contour.
947 Gotos that jump out of this contour must restore the
948 stack level and do the cleanups before actually jumping.
950 DONT_JUMP_IN nonzero means report error there is a jump into this
951 contour from before the beginning of the contour.
952 This is also done if STACK_LEVEL is nonzero. */
955 fixup_gotos (thisblock, stack_level, cleanup_list, first_insn, dont_jump_in)
956 struct nesting *thisblock;
962 struct goto_fixup *f, *prev;
964 /* F is the fixup we are considering; PREV is the previous one. */
965 /* We run this loop in two passes so that cleanups of exited blocks
966 are run first, and blocks that are exited are marked so
969 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
971 /* Test for a fixup that is inactive because it is already handled. */
972 if (f->before_jump == 0)
974 /* Delete inactive fixup from the chain, if that is easy to do. */
976 prev->next = f->next;
978 /* Has this fixup's target label been defined?
979 If so, we can finalize it. */
980 else if (PREV_INSN (f->target_rtl) != 0)
984 /* If this fixup jumped into this contour from before the beginning
985 of this contour, report an error. This code used to use
986 the first non-label insn after f->target_rtl, but that's
987 wrong since such can be added, by things like put_var_into_stack
988 and have INSN_UIDs that are out of the range of the block. */
989 /* ??? Bug: this does not detect jumping in through intermediate
990 blocks that have stack levels or cleanups.
991 It detects only a problem with the innermost block
994 && (dont_jump_in || stack_level || cleanup_list)
995 && INSN_UID (first_insn) < INSN_UID (f->target_rtl)
996 && INSN_UID (first_insn) > INSN_UID (f->before_jump)
997 && ! DECL_ERROR_ISSUED (f->target))
999 error_with_decl (f->target,
1000 "label `%s' used before containing binding contour");
1001 /* Prevent multiple errors for one label. */
1002 DECL_ERROR_ISSUED (f->target) = 1;
1005 /* We will expand the cleanups into a sequence of their own and
1006 then later on we will attach this new sequence to the insn
1007 stream just ahead of the actual jump insn. */
1011 /* Temporarily restore the lexical context where we will
1012 logically be inserting the fixup code. We do this for the
1013 sake of getting the debugging information right. */
1015 (*lang_hooks.decls.pushlevel) (0);
1016 (*lang_hooks.decls.set_block) (f->context);
1018 /* Expand the cleanups for blocks this jump exits. */
1019 if (f->cleanup_list_list)
1022 for (lists = f->cleanup_list_list; lists; lists = TREE_CHAIN (lists))
1023 /* Marked elements correspond to blocks that have been closed.
1024 Do their cleanups. */
1025 if (TREE_ADDRESSABLE (lists)
1026 && TREE_VALUE (lists) != 0)
1028 expand_cleanups (TREE_VALUE (lists), NULL_TREE, 1, 1);
1029 /* Pop any pushes done in the cleanups,
1030 in case function is about to return. */
1031 do_pending_stack_adjust ();
1035 /* Restore stack level for the biggest contour that this
1036 jump jumps out of. */
1038 && ! (f->target_rtl == return_label
1039 && ((TREE_CODE (TREE_TYPE (current_function_decl))
1041 && (TYPE_RETURNS_STACK_DEPRESSED
1042 (TREE_TYPE (current_function_decl))))))
1043 emit_stack_restore (SAVE_BLOCK, f->stack_level, f->before_jump);
1045 /* Finish up the sequence containing the insns which implement the
1046 necessary cleanups, and then attach that whole sequence to the
1047 insn stream just ahead of the actual jump insn. Attaching it
1048 at that point insures that any cleanups which are in fact
1049 implicit C++ object destructions (which must be executed upon
1050 leaving the block) appear (to the debugger) to be taking place
1051 in an area of the generated code where the object(s) being
1052 destructed are still "in scope". */
1054 cleanup_insns = get_insns ();
1055 (*lang_hooks.decls.poplevel) (1, 0, 0);
1058 emit_insn_after (cleanup_insns, f->before_jump);
1064 /* For any still-undefined labels, do the cleanups for this block now.
1065 We must do this now since items in the cleanup list may go out
1066 of scope when the block ends. */
1067 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
1068 if (f->before_jump != 0
1069 && PREV_INSN (f->target_rtl) == 0
1070 /* Label has still not appeared. If we are exiting a block with
1071 a stack level to restore, that started before the fixup,
1072 mark this stack level as needing restoration
1073 when the fixup is later finalized. */
1075 /* Note: if THISBLOCK == 0 and we have a label that hasn't appeared, it
1076 means the label is undefined. That's erroneous, but possible. */
1077 && (thisblock->data.block.block_start_count
1078 <= f->block_start_count))
1080 tree lists = f->cleanup_list_list;
1083 for (; lists; lists = TREE_CHAIN (lists))
1084 /* If the following elt. corresponds to our containing block
1085 then the elt. must be for this block. */
1086 if (TREE_CHAIN (lists) == thisblock->data.block.outer_cleanups)
1089 (*lang_hooks.decls.pushlevel) (0);
1090 (*lang_hooks.decls.set_block) (f->context);
1091 expand_cleanups (TREE_VALUE (lists), NULL_TREE, 1, 1);
1092 do_pending_stack_adjust ();
1093 cleanup_insns = get_insns ();
1094 (*lang_hooks.decls.poplevel) (1, 0, 0);
1096 if (cleanup_insns != 0)
1098 = emit_insn_after (cleanup_insns, f->before_jump);
1100 f->cleanup_list_list = TREE_CHAIN (lists);
1104 f->stack_level = stack_level;
1108 /* Return the number of times character C occurs in string S. */
1110 n_occurrences (c, s)
1120 /* Generate RTL for an asm statement (explicit assembler code).
1121 STRING is a STRING_CST node containing the assembler code text,
1122 or an ADDR_EXPR containing a STRING_CST. VOL nonzero means the
1123 insn is volatile; don't optimize it. */
1126 expand_asm (string, vol)
1132 if (TREE_CODE (string) == ADDR_EXPR)
1133 string = TREE_OPERAND (string, 0);
1135 body = gen_rtx_ASM_INPUT (VOIDmode, TREE_STRING_POINTER (string));
1137 MEM_VOLATILE_P (body) = vol;
1144 /* Parse the output constraint pointed to by *CONSTRAINT_P. It is the
1145 OPERAND_NUMth output operand, indexed from zero. There are NINPUTS
1146 inputs and NOUTPUTS outputs to this extended-asm. Upon return,
1147 *ALLOWS_MEM will be TRUE iff the constraint allows the use of a
1148 memory operand. Similarly, *ALLOWS_REG will be TRUE iff the
1149 constraint allows the use of a register operand. And, *IS_INOUT
1150 will be true if the operand is read-write, i.e., if it is used as
1151 an input as well as an output. If *CONSTRAINT_P is not in
1152 canonical form, it will be made canonical. (Note that `+' will be
1153 replaced with `=' as part of this process.)
1155 Returns TRUE if all went well; FALSE if an error occurred. */
1158 parse_output_constraint (constraint_p, operand_num, ninputs, noutputs,
1159 allows_mem, allows_reg, is_inout)
1160 const char **constraint_p;
1168 const char *constraint = *constraint_p;
1171 /* Assume the constraint doesn't allow the use of either a register
1173 *allows_mem = false;
1174 *allows_reg = false;
1176 /* Allow the `=' or `+' to not be at the beginning of the string,
1177 since it wasn't explicitly documented that way, and there is a
1178 large body of code that puts it last. Swap the character to
1179 the front, so as not to uglify any place else. */
1180 p = strchr (constraint, '=');
1182 p = strchr (constraint, '+');
1184 /* If the string doesn't contain an `=', issue an error
1188 error ("output operand constraint lacks `='");
1192 /* If the constraint begins with `+', then the operand is both read
1193 from and written to. */
1194 *is_inout = (*p == '+');
1196 /* Canonicalize the output constraint so that it begins with `='. */
1197 if (p != constraint || is_inout)
1200 size_t c_len = strlen (constraint);
1202 if (p != constraint)
1203 warning ("output constraint `%c' for operand %d is not at the beginning",
1206 /* Make a copy of the constraint. */
1207 buf = alloca (c_len + 1);
1208 strcpy (buf, constraint);
1209 /* Swap the first character and the `=' or `+'. */
1210 buf[p - constraint] = buf[0];
1211 /* Make sure the first character is an `='. (Until we do this,
1212 it might be a `+'.) */
1214 /* Replace the constraint with the canonicalized string. */
1215 *constraint_p = ggc_alloc_string (buf, c_len);
1216 constraint = *constraint_p;
1219 /* Loop through the constraint string. */
1220 for (p = constraint + 1; *p; p += CONSTRAINT_LEN (*p, p))
1225 error ("operand constraint contains incorrectly positioned '+' or '='");
1229 if (operand_num + 1 == ninputs + noutputs)
1231 error ("`%%' constraint used with last operand");
1236 case 'V': case 'm': case 'o':
1240 case '?': case '!': case '*': case '&': case '#':
1241 case 'E': case 'F': case 'G': case 'H':
1242 case 's': case 'i': case 'n':
1243 case 'I': case 'J': case 'K': case 'L': case 'M':
1244 case 'N': case 'O': case 'P': case ',':
1247 case '0': case '1': case '2': case '3': case '4':
1248 case '5': case '6': case '7': case '8': case '9':
1250 error ("matching constraint not valid in output operand");
1254 /* ??? Before flow, auto inc/dec insns are not supposed to exist,
1255 excepting those that expand_call created. So match memory
1272 if (REG_CLASS_FROM_CONSTRAINT (*p, p) != NO_REGS)
1274 #ifdef EXTRA_CONSTRAINT_STR
1275 else if (EXTRA_ADDRESS_CONSTRAINT (*p, p))
1277 else if (EXTRA_MEMORY_CONSTRAINT (*p, p))
1281 /* Otherwise we can't assume anything about the nature of
1282 the constraint except that it isn't purely registers.
1283 Treat it like "g" and hope for the best. */
1294 /* Similar, but for input constraints. */
1297 parse_input_constraint (constraint_p, input_num, ninputs, noutputs, ninout,
1298 constraints, allows_mem, allows_reg)
1299 const char **constraint_p;
1304 const char * const * constraints;
1308 const char *constraint = *constraint_p;
1309 const char *orig_constraint = constraint;
1310 size_t c_len = strlen (constraint);
1313 /* Assume the constraint doesn't allow the use of either
1314 a register or memory. */
1315 *allows_mem = false;
1316 *allows_reg = false;
1318 /* Make sure constraint has neither `=', `+', nor '&'. */
1320 for (j = 0; j < c_len; j += CONSTRAINT_LEN (constraint[j], constraint+j))
1321 switch (constraint[j])
1323 case '+': case '=': case '&':
1324 if (constraint == orig_constraint)
1326 error ("input operand constraint contains `%c'", constraint[j]);
1332 if (constraint == orig_constraint
1333 && input_num + 1 == ninputs - ninout)
1335 error ("`%%' constraint used with last operand");
1340 case 'V': case 'm': case 'o':
1345 case '?': case '!': case '*': case '#':
1346 case 'E': case 'F': case 'G': case 'H':
1347 case 's': case 'i': case 'n':
1348 case 'I': case 'J': case 'K': case 'L': case 'M':
1349 case 'N': case 'O': case 'P': case ',':
1352 /* Whether or not a numeric constraint allows a register is
1353 decided by the matching constraint, and so there is no need
1354 to do anything special with them. We must handle them in
1355 the default case, so that we don't unnecessarily force
1356 operands to memory. */
1357 case '0': case '1': case '2': case '3': case '4':
1358 case '5': case '6': case '7': case '8': case '9':
1361 unsigned long match;
1363 match = strtoul (constraint + j, &end, 10);
1364 if (match >= (unsigned long) noutputs)
1366 error ("matching constraint references invalid operand number");
1370 /* Try and find the real constraint for this dup. Only do this
1371 if the matching constraint is the only alternative. */
1373 && (j == 0 || (j == 1 && constraint[0] == '%')))
1375 constraint = constraints[match];
1376 *constraint_p = constraint;
1377 c_len = strlen (constraint);
1379 /* ??? At the end of the loop, we will skip the first part of
1380 the matched constraint. This assumes not only that the
1381 other constraint is an output constraint, but also that
1382 the '=' or '+' come first. */
1386 j = end - constraint;
1387 /* Anticipate increment at end of loop. */
1402 if (! ISALPHA (constraint[j]))
1404 error ("invalid punctuation `%c' in constraint", constraint[j]);
1407 if (REG_CLASS_FROM_CONSTRAINT (constraint[j], constraint + j)
1410 #ifdef EXTRA_CONSTRAINT_STR
1411 else if (EXTRA_ADDRESS_CONSTRAINT (constraint[j], constraint + j))
1413 else if (EXTRA_MEMORY_CONSTRAINT (constraint[j], constraint + j))
1417 /* Otherwise we can't assume anything about the nature of
1418 the constraint except that it isn't purely registers.
1419 Treat it like "g" and hope for the best. */
1430 /* Check for overlap between registers marked in CLOBBERED_REGS and
1431 anything inappropriate in DECL. Emit error and return TRUE for error,
1435 decl_conflicts_with_clobbers_p (decl, clobbered_regs)
1437 const HARD_REG_SET clobbered_regs;
1439 /* Conflicts between asm-declared register variables and the clobber
1440 list are not allowed. */
1441 if ((TREE_CODE (decl) == VAR_DECL || TREE_CODE (decl) == PARM_DECL)
1442 && DECL_REGISTER (decl)
1443 && REG_P (DECL_RTL (decl))
1444 && REGNO (DECL_RTL (decl)) < FIRST_PSEUDO_REGISTER)
1446 rtx reg = DECL_RTL (decl);
1449 for (regno = REGNO (reg);
1450 regno < (REGNO (reg)
1451 + HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg)));
1453 if (TEST_HARD_REG_BIT (clobbered_regs, regno))
1455 error ("asm-specifier for variable `%s' conflicts with asm clobber list",
1456 IDENTIFIER_POINTER (DECL_NAME (decl)));
1458 /* Reset registerness to stop multiple errors emitted for a
1460 DECL_REGISTER (decl) = 0;
1467 /* Generate RTL for an asm statement with arguments.
1468 STRING is the instruction template.
1469 OUTPUTS is a list of output arguments (lvalues); INPUTS a list of inputs.
1470 Each output or input has an expression in the TREE_VALUE and
1471 and a tree list in TREE_PURPOSE which in turn contains a constraint
1472 name in TREE_VALUE (or NULL_TREE) and a constraint string
1474 CLOBBERS is a list of STRING_CST nodes each naming a hard register
1475 that is clobbered by this insn.
1477 Not all kinds of lvalue that may appear in OUTPUTS can be stored directly.
1478 Some elements of OUTPUTS may be replaced with trees representing temporary
1479 values. The caller should copy those temporary values to the originally
1482 VOL nonzero means the insn is volatile; don't optimize it. */
1485 expand_asm_operands (string, outputs, inputs, clobbers, vol, filename, line)
1486 tree string, outputs, inputs, clobbers;
1488 const char *filename;
1491 rtvec argvec, constraintvec;
1493 int ninputs = list_length (inputs);
1494 int noutputs = list_length (outputs);
1497 HARD_REG_SET clobbered_regs;
1498 int clobber_conflict_found = 0;
1501 /* Vector of RTX's of evaluated output operands. */
1502 rtx *output_rtx = (rtx *) alloca (noutputs * sizeof (rtx));
1503 int *inout_opnum = (int *) alloca (noutputs * sizeof (int));
1504 rtx *real_output_rtx = (rtx *) alloca (noutputs * sizeof (rtx));
1505 enum machine_mode *inout_mode
1506 = (enum machine_mode *) alloca (noutputs * sizeof (enum machine_mode));
1507 const char **constraints
1508 = (const char **) alloca ((noutputs + ninputs) * sizeof (const char *));
1509 int old_generating_concat_p = generating_concat_p;
1511 /* An ASM with no outputs needs to be treated as volatile, for now. */
1515 if (! check_operand_nalternatives (outputs, inputs))
1518 if (! check_unique_operand_names (outputs, inputs))
1521 string = resolve_operand_names (string, outputs, inputs, constraints);
1523 #ifdef MD_ASM_CLOBBERS
1524 /* Sometimes we wish to automatically clobber registers across an asm.
1525 Case in point is when the i386 backend moved from cc0 to a hard reg --
1526 maintaining source-level compatibility means automatically clobbering
1527 the flags register. */
1528 MD_ASM_CLOBBERS (clobbers);
1531 /* Count the number of meaningful clobbered registers, ignoring what
1532 we would ignore later. */
1534 CLEAR_HARD_REG_SET (clobbered_regs);
1535 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1537 const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1539 i = decode_reg_name (regname);
1540 if (i >= 0 || i == -4)
1543 error ("unknown register name `%s' in `asm'", regname);
1545 /* Mark clobbered registers. */
1548 /* Clobbering the PIC register is an error */
1549 if (i == (int) PIC_OFFSET_TABLE_REGNUM)
1551 error ("PIC register `%s' clobbered in `asm'", regname);
1555 SET_HARD_REG_BIT (clobbered_regs, i);
1561 /* First pass over inputs and outputs checks validity and sets
1562 mark_addressable if needed. */
1565 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1567 tree val = TREE_VALUE (tail);
1568 tree type = TREE_TYPE (val);
1569 const char *constraint;
1574 /* If there's an erroneous arg, emit no insn. */
1575 if (type == error_mark_node)
1578 /* Try to parse the output constraint. If that fails, there's
1579 no point in going further. */
1580 constraint = constraints[i];
1581 if (!parse_output_constraint (&constraint, i, ninputs, noutputs,
1582 &allows_mem, &allows_reg, &is_inout))
1589 && GET_CODE (DECL_RTL (val)) == REG
1590 && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type))))
1591 (*lang_hooks.mark_addressable) (val);
1598 if (ninputs + noutputs > MAX_RECOG_OPERANDS)
1600 error ("more than %d operands in `asm'", MAX_RECOG_OPERANDS);
1604 for (i = 0, tail = inputs; tail; i++, tail = TREE_CHAIN (tail))
1606 bool allows_reg, allows_mem;
1607 const char *constraint;
1609 /* If there's an erroneous arg, emit no insn, because the ASM_INPUT
1610 would get VOIDmode and that could cause a crash in reload. */
1611 if (TREE_TYPE (TREE_VALUE (tail)) == error_mark_node)
1614 constraint = constraints[i + noutputs];
1615 if (! parse_input_constraint (&constraint, i, ninputs, noutputs, ninout,
1616 constraints, &allows_mem, &allows_reg))
1619 if (! allows_reg && allows_mem)
1620 (*lang_hooks.mark_addressable) (TREE_VALUE (tail));
1623 /* Second pass evaluates arguments. */
1626 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1628 tree val = TREE_VALUE (tail);
1629 tree type = TREE_TYPE (val);
1635 if (!parse_output_constraint (&constraints[i], i, ninputs,
1636 noutputs, &allows_mem, &allows_reg,
1640 /* If an output operand is not a decl or indirect ref and our constraint
1641 allows a register, make a temporary to act as an intermediate.
1642 Make the asm insn write into that, then our caller will copy it to
1643 the real output operand. Likewise for promoted variables. */
1645 generating_concat_p = 0;
1647 real_output_rtx[i] = NULL_RTX;
1648 if ((TREE_CODE (val) == INDIRECT_REF
1651 && (allows_mem || GET_CODE (DECL_RTL (val)) == REG)
1652 && ! (GET_CODE (DECL_RTL (val)) == REG
1653 && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type)))
1657 op = expand_expr (val, NULL_RTX, VOIDmode, EXPAND_WRITE);
1658 if (GET_CODE (op) == MEM)
1659 op = validize_mem (op);
1661 if (! allows_reg && GET_CODE (op) != MEM)
1662 error ("output number %d not directly addressable", i);
1663 if ((! allows_mem && GET_CODE (op) == MEM)
1664 || GET_CODE (op) == CONCAT)
1666 real_output_rtx[i] = protect_from_queue (op, 1);
1667 op = gen_reg_rtx (GET_MODE (op));
1669 emit_move_insn (op, real_output_rtx[i]);
1674 op = assign_temp (type, 0, 0, 1);
1675 op = validize_mem (op);
1676 TREE_VALUE (tail) = make_tree (type, op);
1680 generating_concat_p = old_generating_concat_p;
1684 inout_mode[ninout] = TYPE_MODE (type);
1685 inout_opnum[ninout++] = i;
1688 if (decl_conflicts_with_clobbers_p (val, clobbered_regs))
1689 clobber_conflict_found = 1;
1692 /* Make vectors for the expression-rtx, constraint strings,
1693 and named operands. */
1695 argvec = rtvec_alloc (ninputs);
1696 constraintvec = rtvec_alloc (ninputs);
1698 body = gen_rtx_ASM_OPERANDS ((noutputs == 0 ? VOIDmode
1699 : GET_MODE (output_rtx[0])),
1700 TREE_STRING_POINTER (string),
1701 empty_string, 0, argvec, constraintvec,
1704 MEM_VOLATILE_P (body) = vol;
1706 /* Eval the inputs and put them into ARGVEC.
1707 Put their constraints into ASM_INPUTs and store in CONSTRAINTS. */
1709 for (i = 0, tail = inputs; tail; tail = TREE_CHAIN (tail), ++i)
1711 bool allows_reg, allows_mem;
1712 const char *constraint;
1716 constraint = constraints[i + noutputs];
1717 if (! parse_input_constraint (&constraint, i, ninputs, noutputs, ninout,
1718 constraints, &allows_mem, &allows_reg))
1721 generating_concat_p = 0;
1723 val = TREE_VALUE (tail);
1724 type = TREE_TYPE (val);
1725 op = expand_expr (val, NULL_RTX, VOIDmode, 0);
1727 /* Never pass a CONCAT to an ASM. */
1728 if (GET_CODE (op) == CONCAT)
1729 op = force_reg (GET_MODE (op), op);
1730 else if (GET_CODE (op) == MEM)
1731 op = validize_mem (op);
1733 if (asm_operand_ok (op, constraint) <= 0)
1736 op = force_reg (TYPE_MODE (type), op);
1737 else if (!allows_mem)
1738 warning ("asm operand %d probably doesn't match constraints",
1740 else if (CONSTANT_P (op))
1742 op = force_const_mem (TYPE_MODE (type), op);
1743 op = validize_mem (op);
1745 else if (GET_CODE (op) == REG
1746 || GET_CODE (op) == SUBREG
1747 || GET_CODE (op) == ADDRESSOF
1748 || GET_CODE (op) == CONCAT)
1750 tree qual_type = build_qualified_type (type,
1752 | TYPE_QUAL_CONST));
1753 rtx memloc = assign_temp (qual_type, 1, 1, 1);
1754 memloc = validize_mem (memloc);
1755 emit_move_insn (memloc, op);
1759 else if (GET_CODE (op) == MEM && MEM_VOLATILE_P (op))
1761 /* We won't recognize volatile memory as available a
1762 memory_operand at this point. Ignore it. */
1764 else if (queued_subexp_p (op))
1767 /* ??? Leave this only until we have experience with what
1768 happens in combine and elsewhere when constraints are
1770 warning ("asm operand %d probably doesn't match constraints",
1774 generating_concat_p = old_generating_concat_p;
1775 ASM_OPERANDS_INPUT (body, i) = op;
1777 ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, i)
1778 = gen_rtx_ASM_INPUT (TYPE_MODE (type), constraints[i + noutputs]);
1780 if (decl_conflicts_with_clobbers_p (val, clobbered_regs))
1781 clobber_conflict_found = 1;
1784 /* Protect all the operands from the queue now that they have all been
1787 generating_concat_p = 0;
1789 for (i = 0; i < ninputs - ninout; i++)
1790 ASM_OPERANDS_INPUT (body, i)
1791 = protect_from_queue (ASM_OPERANDS_INPUT (body, i), 0);
1793 for (i = 0; i < noutputs; i++)
1794 output_rtx[i] = protect_from_queue (output_rtx[i], 1);
1796 /* For in-out operands, copy output rtx to input rtx. */
1797 for (i = 0; i < ninout; i++)
1799 int j = inout_opnum[i];
1802 ASM_OPERANDS_INPUT (body, ninputs - ninout + i)
1805 sprintf (buffer, "%d", j);
1806 ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, ninputs - ninout + i)
1807 = gen_rtx_ASM_INPUT (inout_mode[i], ggc_alloc_string (buffer, -1));
1810 generating_concat_p = old_generating_concat_p;
1812 /* Now, for each output, construct an rtx
1813 (set OUTPUT (asm_operands INSN OUTPUTCONSTRAINT OUTPUTNUMBER
1814 ARGVEC CONSTRAINTS OPNAMES))
1815 If there is more than one, put them inside a PARALLEL. */
1817 if (noutputs == 1 && nclobbers == 0)
1819 ASM_OPERANDS_OUTPUT_CONSTRAINT (body) = constraints[0];
1820 emit_insn (gen_rtx_SET (VOIDmode, output_rtx[0], body));
1823 else if (noutputs == 0 && nclobbers == 0)
1825 /* No output operands: put in a raw ASM_OPERANDS rtx. */
1837 body = gen_rtx_PARALLEL (VOIDmode, rtvec_alloc (num + nclobbers));
1839 /* For each output operand, store a SET. */
1840 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1842 XVECEXP (body, 0, i)
1843 = gen_rtx_SET (VOIDmode,
1845 gen_rtx_ASM_OPERANDS
1846 (GET_MODE (output_rtx[i]),
1847 TREE_STRING_POINTER (string),
1848 constraints[i], i, argvec, constraintvec,
1851 MEM_VOLATILE_P (SET_SRC (XVECEXP (body, 0, i))) = vol;
1854 /* If there are no outputs (but there are some clobbers)
1855 store the bare ASM_OPERANDS into the PARALLEL. */
1858 XVECEXP (body, 0, i++) = obody;
1860 /* Store (clobber REG) for each clobbered register specified. */
1862 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1864 const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1865 int j = decode_reg_name (regname);
1870 if (j == -3) /* `cc', which is not a register */
1873 if (j == -4) /* `memory', don't cache memory across asm */
1875 XVECEXP (body, 0, i++)
1876 = gen_rtx_CLOBBER (VOIDmode,
1879 gen_rtx_SCRATCH (VOIDmode)));
1883 /* Ignore unknown register, error already signaled. */
1887 /* Use QImode since that's guaranteed to clobber just one reg. */
1888 clobbered_reg = gen_rtx_REG (QImode, j);
1890 /* Do sanity check for overlap between clobbers and respectively
1891 input and outputs that hasn't been handled. Such overlap
1892 should have been detected and reported above. */
1893 if (!clobber_conflict_found)
1897 /* We test the old body (obody) contents to avoid tripping
1898 over the under-construction body. */
1899 for (opno = 0; opno < noutputs; opno++)
1900 if (reg_overlap_mentioned_p (clobbered_reg, output_rtx[opno]))
1901 internal_error ("asm clobber conflict with output operand");
1903 for (opno = 0; opno < ninputs - ninout; opno++)
1904 if (reg_overlap_mentioned_p (clobbered_reg,
1905 ASM_OPERANDS_INPUT (obody, opno)))
1906 internal_error ("asm clobber conflict with input operand");
1909 XVECEXP (body, 0, i++)
1910 = gen_rtx_CLOBBER (VOIDmode, clobbered_reg);
1916 /* For any outputs that needed reloading into registers, spill them
1917 back to where they belong. */
1918 for (i = 0; i < noutputs; ++i)
1919 if (real_output_rtx[i])
1920 emit_move_insn (real_output_rtx[i], output_rtx[i]);
1925 /* A subroutine of expand_asm_operands. Check that all operands have
1926 the same number of alternatives. Return true if so. */
1929 check_operand_nalternatives (outputs, inputs)
1930 tree outputs, inputs;
1932 if (outputs || inputs)
1934 tree tmp = TREE_PURPOSE (outputs ? outputs : inputs);
1936 = n_occurrences (',', TREE_STRING_POINTER (TREE_VALUE (tmp)));
1939 if (nalternatives + 1 > MAX_RECOG_ALTERNATIVES)
1941 error ("too many alternatives in `asm'");
1948 const char *constraint
1949 = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tmp)));
1951 if (n_occurrences (',', constraint) != nalternatives)
1953 error ("operand constraints for `asm' differ in number of alternatives");
1957 if (TREE_CHAIN (tmp))
1958 tmp = TREE_CHAIN (tmp);
1960 tmp = next, next = 0;
1967 /* A subroutine of expand_asm_operands. Check that all operand names
1968 are unique. Return true if so. We rely on the fact that these names
1969 are identifiers, and so have been canonicalized by get_identifier,
1970 so all we need are pointer comparisons. */
1973 check_unique_operand_names (outputs, inputs)
1974 tree outputs, inputs;
1978 for (i = outputs; i ; i = TREE_CHAIN (i))
1980 tree i_name = TREE_PURPOSE (TREE_PURPOSE (i));
1984 for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
1985 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1989 for (i = inputs; i ; i = TREE_CHAIN (i))
1991 tree i_name = TREE_PURPOSE (TREE_PURPOSE (i));
1995 for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
1996 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1998 for (j = outputs; j ; j = TREE_CHAIN (j))
1999 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
2006 error ("duplicate asm operand name '%s'",
2007 TREE_STRING_POINTER (TREE_PURPOSE (TREE_PURPOSE (i))));
2011 /* A subroutine of expand_asm_operands. Resolve the names of the operands
2012 in *POUTPUTS and *PINPUTS to numbers, and replace the name expansions in
2013 STRING and in the constraints to those numbers. */
2016 resolve_operand_names (string, outputs, inputs, pconstraints)
2018 tree outputs, inputs;
2019 const char **pconstraints;
2021 char *buffer = xstrdup (TREE_STRING_POINTER (string));
2025 /* Assume that we will not need extra space to perform the substitution.
2026 This because we get to remove '[' and ']', which means we cannot have
2027 a problem until we have more than 999 operands. */
2030 while ((p = strchr (p, '%')) != NULL)
2034 else if (ISALPHA (p[1]) && p[2] == '[')
2042 p = resolve_operand_name_1 (p, outputs, inputs);
2045 string = build_string (strlen (buffer), buffer);
2048 /* Collect output constraints here because it's convenient.
2049 There should be no named operands here; this is verified
2050 in expand_asm_operand. */
2051 for (t = outputs; t ; t = TREE_CHAIN (t), pconstraints++)
2052 *pconstraints = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
2054 /* Substitute [<name>] in input constraint strings. */
2055 for (t = inputs; t ; t = TREE_CHAIN (t), pconstraints++)
2057 const char *c = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
2058 if (strchr (c, '[') == NULL)
2062 p = buffer = xstrdup (c);
2063 while ((p = strchr (p, '[')) != NULL)
2064 p = resolve_operand_name_1 (p, outputs, inputs);
2066 *pconstraints = ggc_alloc_string (buffer, -1);
2074 /* A subroutine of resolve_operand_names. P points to the '[' for a
2075 potential named operand of the form [<name>]. In place, replace
2076 the name and brackets with a number. Return a pointer to the
2077 balance of the string after substitution. */
2080 resolve_operand_name_1 (p, outputs, inputs)
2082 tree outputs, inputs;
2089 /* Collect the operand name. */
2090 q = strchr (p, ']');
2093 error ("missing close brace for named operand");
2094 return strchr (p, '\0');
2098 /* Resolve the name to a number. */
2099 for (op = 0, t = outputs; t ; t = TREE_CHAIN (t), op++)
2101 tree name = TREE_PURPOSE (TREE_PURPOSE (t));
2104 const char *c = TREE_STRING_POINTER (name);
2105 if (strncmp (c, p + 1, len) == 0 && c[len] == '\0')
2109 for (t = inputs; t ; t = TREE_CHAIN (t), op++)
2111 tree name = TREE_PURPOSE (TREE_PURPOSE (t));
2114 const char *c = TREE_STRING_POINTER (name);
2115 if (strncmp (c, p + 1, len) == 0 && c[len] == '\0')
2121 error ("undefined named operand '%s'", p + 1);
2125 /* Replace the name with the number. Unfortunately, not all libraries
2126 get the return value of sprintf correct, so search for the end of the
2127 generated string by hand. */
2128 sprintf (p, "%d", op);
2129 p = strchr (p, '\0');
2131 /* Verify the no extra buffer space assumption. */
2135 /* Shift the rest of the buffer down to fill the gap. */
2136 memmove (p, q + 1, strlen (q + 1) + 1);
2141 /* Generate RTL to evaluate the expression EXP
2142 and remember it in case this is the VALUE in a ({... VALUE; }) constr.
2143 Provided just for backward-compatibility. expand_expr_stmt_value()
2144 should be used for new code. */
2147 expand_expr_stmt (exp)
2150 expand_expr_stmt_value (exp, -1, 1);
2153 /* Generate RTL to evaluate the expression EXP. WANT_VALUE tells
2154 whether to (1) save the value of the expression, (0) discard it or
2155 (-1) use expr_stmts_for_value to tell. The use of -1 is
2156 deprecated, and retained only for backward compatibility. */
2159 expand_expr_stmt_value (exp, want_value, maybe_last)
2161 int want_value, maybe_last;
2166 if (want_value == -1)
2167 want_value = expr_stmts_for_value != 0;
2169 /* If -Wextra, warn about statements with no side effects,
2170 except for an explicit cast to void (e.g. for assert()), and
2171 except for last statement in ({...}) where they may be useful. */
2173 && (expr_stmts_for_value == 0 || ! maybe_last)
2174 && exp != error_mark_node)
2176 if (! TREE_SIDE_EFFECTS (exp))
2178 if ((extra_warnings || warn_unused_value)
2179 && !(TREE_CODE (exp) == CONVERT_EXPR
2180 && VOID_TYPE_P (TREE_TYPE (exp))))
2181 warning_with_file_and_line (emit_filename, emit_lineno,
2182 "statement with no effect");
2184 else if (warn_unused_value)
2185 warn_if_unused_value (exp);
2188 /* If EXP is of function type and we are expanding statements for
2189 value, convert it to pointer-to-function. */
2190 if (want_value && TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE)
2191 exp = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (exp)), exp);
2193 /* The call to `expand_expr' could cause last_expr_type and
2194 last_expr_value to get reset. Therefore, we set last_expr_value
2195 and last_expr_type *after* calling expand_expr. */
2196 value = expand_expr (exp, want_value ? NULL_RTX : const0_rtx,
2198 type = TREE_TYPE (exp);
2200 /* If all we do is reference a volatile value in memory,
2201 copy it to a register to be sure it is actually touched. */
2202 if (value && GET_CODE (value) == MEM && TREE_THIS_VOLATILE (exp))
2204 if (TYPE_MODE (type) == VOIDmode)
2206 else if (TYPE_MODE (type) != BLKmode)
2207 value = copy_to_reg (value);
2210 rtx lab = gen_label_rtx ();
2212 /* Compare the value with itself to reference it. */
2213 emit_cmp_and_jump_insns (value, value, EQ,
2214 expand_expr (TYPE_SIZE (type),
2215 NULL_RTX, VOIDmode, 0),
2221 /* If this expression is part of a ({...}) and is in memory, we may have
2222 to preserve temporaries. */
2223 preserve_temp_slots (value);
2225 /* Free any temporaries used to evaluate this expression. Any temporary
2226 used as a result of this expression will already have been preserved
2232 last_expr_value = value;
2233 last_expr_type = type;
2239 /* Warn if EXP contains any computations whose results are not used.
2240 Return 1 if a warning is printed; 0 otherwise. */
2243 warn_if_unused_value (exp)
2246 if (TREE_USED (exp))
2249 /* Don't warn about void constructs. This includes casting to void,
2250 void function calls, and statement expressions with a final cast
2252 if (VOID_TYPE_P (TREE_TYPE (exp)))
2255 switch (TREE_CODE (exp))
2257 case PREINCREMENT_EXPR:
2258 case POSTINCREMENT_EXPR:
2259 case PREDECREMENT_EXPR:
2260 case POSTDECREMENT_EXPR:
2265 case METHOD_CALL_EXPR:
2267 case TRY_CATCH_EXPR:
2268 case WITH_CLEANUP_EXPR:
2273 /* For a binding, warn if no side effect within it. */
2274 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2277 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2279 case TRUTH_ORIF_EXPR:
2280 case TRUTH_ANDIF_EXPR:
2281 /* In && or ||, warn if 2nd operand has no side effect. */
2282 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2285 if (TREE_NO_UNUSED_WARNING (exp))
2287 if (warn_if_unused_value (TREE_OPERAND (exp, 0)))
2289 /* Let people do `(foo (), 0)' without a warning. */
2290 if (TREE_CONSTANT (TREE_OPERAND (exp, 1)))
2292 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2296 case NON_LVALUE_EXPR:
2297 /* Don't warn about conversions not explicit in the user's program. */
2298 if (TREE_NO_UNUSED_WARNING (exp))
2300 /* Assignment to a cast usually results in a cast of a modify.
2301 Don't complain about that. There can be an arbitrary number of
2302 casts before the modify, so we must loop until we find the first
2303 non-cast expression and then test to see if that is a modify. */
2305 tree tem = TREE_OPERAND (exp, 0);
2307 while (TREE_CODE (tem) == CONVERT_EXPR || TREE_CODE (tem) == NOP_EXPR)
2308 tem = TREE_OPERAND (tem, 0);
2310 if (TREE_CODE (tem) == MODIFY_EXPR || TREE_CODE (tem) == INIT_EXPR
2311 || TREE_CODE (tem) == CALL_EXPR)
2317 /* Don't warn about automatic dereferencing of references, since
2318 the user cannot control it. */
2319 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (exp, 0))) == REFERENCE_TYPE)
2320 return warn_if_unused_value (TREE_OPERAND (exp, 0));
2324 /* Referencing a volatile value is a side effect, so don't warn. */
2326 || TREE_CODE_CLASS (TREE_CODE (exp)) == 'r')
2327 && TREE_THIS_VOLATILE (exp))
2330 /* If this is an expression which has no operands, there is no value
2331 to be unused. There are no such language-independent codes,
2332 but front ends may define such. */
2333 if (TREE_CODE_CLASS (TREE_CODE (exp)) == 'e'
2334 && TREE_CODE_LENGTH (TREE_CODE (exp)) == 0)
2338 /* If this is an expression with side effects, don't warn. */
2339 if (TREE_SIDE_EFFECTS (exp))
2342 warning_with_file_and_line (emit_filename, emit_lineno,
2343 "value computed is not used");
2348 /* Clear out the memory of the last expression evaluated. */
2353 last_expr_type = NULL_TREE;
2354 last_expr_value = NULL_RTX;
2357 /* Begin a statement-expression, i.e., a series of statements which
2358 may return a value. Return the RTL_EXPR for this statement expr.
2359 The caller must save that value and pass it to
2360 expand_end_stmt_expr. If HAS_SCOPE is nonzero, temporaries created
2361 in the statement-expression are deallocated at the end of the
2365 expand_start_stmt_expr (has_scope)
2370 /* Make the RTL_EXPR node temporary, not momentary,
2371 so that rtl_expr_chain doesn't become garbage. */
2372 t = make_node (RTL_EXPR);
2373 do_pending_stack_adjust ();
2375 start_sequence_for_rtl_expr (t);
2379 expr_stmts_for_value++;
2383 /* Restore the previous state at the end of a statement that returns a value.
2384 Returns a tree node representing the statement's value and the
2385 insns to compute the value.
2387 The nodes of that expression have been freed by now, so we cannot use them.
2388 But we don't want to do that anyway; the expression has already been
2389 evaluated and now we just want to use the value. So generate a RTL_EXPR
2390 with the proper type and RTL value.
2392 If the last substatement was not an expression,
2393 return something with type `void'. */
2396 expand_end_stmt_expr (t)
2401 if (! last_expr_value || ! last_expr_type)
2403 last_expr_value = const0_rtx;
2404 last_expr_type = void_type_node;
2406 else if (GET_CODE (last_expr_value) != REG && ! CONSTANT_P (last_expr_value))
2407 /* Remove any possible QUEUED. */
2408 last_expr_value = protect_from_queue (last_expr_value, 0);
2412 TREE_TYPE (t) = last_expr_type;
2413 RTL_EXPR_RTL (t) = last_expr_value;
2414 RTL_EXPR_SEQUENCE (t) = get_insns ();
2416 rtl_expr_chain = tree_cons (NULL_TREE, t, rtl_expr_chain);
2420 /* Don't consider deleting this expr or containing exprs at tree level. */
2421 TREE_SIDE_EFFECTS (t) = 1;
2422 /* Propagate volatility of the actual RTL expr. */
2423 TREE_THIS_VOLATILE (t) = volatile_refs_p (last_expr_value);
2426 expr_stmts_for_value--;
2431 /* Generate RTL for the start of an if-then. COND is the expression
2432 whose truth should be tested.
2434 If EXITFLAG is nonzero, this conditional is visible to
2435 `exit_something'. */
2438 expand_start_cond (cond, exitflag)
2442 struct nesting *thiscond = ALLOC_NESTING ();
2444 /* Make an entry on cond_stack for the cond we are entering. */
2446 thiscond->desc = COND_NESTING;
2447 thiscond->next = cond_stack;
2448 thiscond->all = nesting_stack;
2449 thiscond->depth = ++nesting_depth;
2450 thiscond->data.cond.next_label = gen_label_rtx ();
2451 /* Before we encounter an `else', we don't need a separate exit label
2452 unless there are supposed to be exit statements
2453 to exit this conditional. */
2454 thiscond->exit_label = exitflag ? gen_label_rtx () : 0;
2455 thiscond->data.cond.endif_label = thiscond->exit_label;
2456 cond_stack = thiscond;
2457 nesting_stack = thiscond;
2459 do_jump (cond, thiscond->data.cond.next_label, NULL_RTX);
2462 /* Generate RTL between then-clause and the elseif-clause
2463 of an if-then-elseif-.... */
2466 expand_start_elseif (cond)
2469 if (cond_stack->data.cond.endif_label == 0)
2470 cond_stack->data.cond.endif_label = gen_label_rtx ();
2471 emit_jump (cond_stack->data.cond.endif_label);
2472 emit_label (cond_stack->data.cond.next_label);
2473 cond_stack->data.cond.next_label = gen_label_rtx ();
2474 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
2477 /* Generate RTL between the then-clause and the else-clause
2478 of an if-then-else. */
2481 expand_start_else ()
2483 if (cond_stack->data.cond.endif_label == 0)
2484 cond_stack->data.cond.endif_label = gen_label_rtx ();
2486 emit_jump (cond_stack->data.cond.endif_label);
2487 emit_label (cond_stack->data.cond.next_label);
2488 cond_stack->data.cond.next_label = 0; /* No more _else or _elseif calls. */
2491 /* After calling expand_start_else, turn this "else" into an "else if"
2492 by providing another condition. */
2495 expand_elseif (cond)
2498 cond_stack->data.cond.next_label = gen_label_rtx ();
2499 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
2502 /* Generate RTL for the end of an if-then.
2503 Pop the record for it off of cond_stack. */
2508 struct nesting *thiscond = cond_stack;
2510 do_pending_stack_adjust ();
2511 if (thiscond->data.cond.next_label)
2512 emit_label (thiscond->data.cond.next_label);
2513 if (thiscond->data.cond.endif_label)
2514 emit_label (thiscond->data.cond.endif_label);
2516 POPSTACK (cond_stack);
2520 /* Generate RTL for the start of a loop. EXIT_FLAG is nonzero if this
2521 loop should be exited by `exit_something'. This is a loop for which
2522 `expand_continue' will jump to the top of the loop.
2524 Make an entry on loop_stack to record the labels associated with
2528 expand_start_loop (exit_flag)
2531 struct nesting *thisloop = ALLOC_NESTING ();
2533 /* Make an entry on loop_stack for the loop we are entering. */
2535 thisloop->desc = LOOP_NESTING;
2536 thisloop->next = loop_stack;
2537 thisloop->all = nesting_stack;
2538 thisloop->depth = ++nesting_depth;
2539 thisloop->data.loop.start_label = gen_label_rtx ();
2540 thisloop->data.loop.end_label = gen_label_rtx ();
2541 thisloop->data.loop.continue_label = thisloop->data.loop.start_label;
2542 thisloop->exit_label = exit_flag ? thisloop->data.loop.end_label : 0;
2543 loop_stack = thisloop;
2544 nesting_stack = thisloop;
2546 do_pending_stack_adjust ();
2548 emit_note (NULL, NOTE_INSN_LOOP_BEG);
2549 emit_label (thisloop->data.loop.start_label);
2554 /* Like expand_start_loop but for a loop where the continuation point
2555 (for expand_continue_loop) will be specified explicitly. */
2558 expand_start_loop_continue_elsewhere (exit_flag)
2561 struct nesting *thisloop = expand_start_loop (exit_flag);
2562 loop_stack->data.loop.continue_label = gen_label_rtx ();
2566 /* Begin a null, aka do { } while (0) "loop". But since the contents
2567 of said loop can still contain a break, we must frob the loop nest. */
2570 expand_start_null_loop ()
2572 struct nesting *thisloop = ALLOC_NESTING ();
2574 /* Make an entry on loop_stack for the loop we are entering. */
2576 thisloop->desc = LOOP_NESTING;
2577 thisloop->next = loop_stack;
2578 thisloop->all = nesting_stack;
2579 thisloop->depth = ++nesting_depth;
2580 thisloop->data.loop.start_label = emit_note (NULL, NOTE_INSN_DELETED);
2581 thisloop->data.loop.end_label = gen_label_rtx ();
2582 thisloop->data.loop.continue_label = thisloop->data.loop.end_label;
2583 thisloop->exit_label = thisloop->data.loop.end_label;
2584 loop_stack = thisloop;
2585 nesting_stack = thisloop;
2590 /* Specify the continuation point for a loop started with
2591 expand_start_loop_continue_elsewhere.
2592 Use this at the point in the code to which a continue statement
2596 expand_loop_continue_here ()
2598 do_pending_stack_adjust ();
2599 emit_note (NULL, NOTE_INSN_LOOP_CONT);
2600 emit_label (loop_stack->data.loop.continue_label);
2603 /* Finish a loop. Generate a jump back to the top and the loop-exit label.
2604 Pop the block off of loop_stack. */
2609 rtx start_label = loop_stack->data.loop.start_label;
2611 int eh_regions, debug_blocks;
2614 /* Mark the continue-point at the top of the loop if none elsewhere. */
2615 if (start_label == loop_stack->data.loop.continue_label)
2616 emit_note_before (NOTE_INSN_LOOP_CONT, start_label);
2618 do_pending_stack_adjust ();
2620 /* If the loop starts with a loop exit, roll that to the end where
2621 it will optimize together with the jump back.
2623 If the loop presently looks like this (in pseudo-C):
2627 if (test) goto end_label;
2633 transform it to look like:
2640 if (test) goto end_label;
2644 We rely on the presence of NOTE_INSN_LOOP_END_TOP_COND to mark
2645 the end of the entry conditional. Without this, our lexical scan
2646 can't tell the difference between an entry conditional and a
2647 body conditional that exits the loop. Mistaking the two means
2648 that we can misplace the NOTE_INSN_LOOP_CONT note, which can
2649 screw up loop unrolling.
2651 Things will be oh so much better when loop optimization is done
2652 off of a proper control flow graph... */
2654 /* Scan insns from the top of the loop looking for the END_TOP_COND note. */
2657 eh_regions = debug_blocks = 0;
2658 for (etc_note = start_label; etc_note ; etc_note = NEXT_INSN (etc_note))
2659 if (GET_CODE (etc_note) == NOTE)
2661 if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_LOOP_END_TOP_COND)
2664 /* We must not walk into a nested loop. */
2665 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_LOOP_BEG)
2667 etc_note = NULL_RTX;
2671 /* At the same time, scan for EH region notes, as we don't want
2672 to scrog region nesting. This shouldn't happen, but... */
2673 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_EH_REGION_BEG)
2675 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_EH_REGION_END)
2677 if (--eh_regions < 0)
2678 /* We've come to the end of an EH region, but never saw the
2679 beginning of that region. That means that an EH region
2680 begins before the top of the loop, and ends in the middle
2681 of it. The existence of such a situation violates a basic
2682 assumption in this code, since that would imply that even
2683 when EH_REGIONS is zero, we might move code out of an
2684 exception region. */
2688 /* Likewise for debug scopes. In this case we'll either (1) move
2689 all of the notes if they are properly nested or (2) leave the
2690 notes alone and only rotate the loop at high optimization
2691 levels when we expect to scrog debug info. */
2692 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_BLOCK_BEG)
2694 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_BLOCK_END)
2697 else if (INSN_P (etc_note))
2704 && (debug_blocks == 0 || optimize >= 2)
2705 && NEXT_INSN (etc_note) != NULL_RTX
2706 && ! any_condjump_p (get_last_insn ()))
2708 /* We found one. Move everything from START to ETC to the end
2709 of the loop, and add a jump from the top of the loop. */
2710 rtx top_label = gen_label_rtx ();
2711 rtx start_move = start_label;
2713 /* If the start label is preceded by a NOTE_INSN_LOOP_CONT note,
2714 then we want to move this note also. */
2715 if (GET_CODE (PREV_INSN (start_move)) == NOTE
2716 && NOTE_LINE_NUMBER (PREV_INSN (start_move)) == NOTE_INSN_LOOP_CONT)
2717 start_move = PREV_INSN (start_move);
2719 emit_label_before (top_label, start_move);
2721 /* Actually move the insns. If the debug scopes are nested, we
2722 can move everything at once. Otherwise we have to move them
2723 one by one and squeeze out the block notes. */
2724 if (debug_blocks == 0)
2725 reorder_insns (start_move, etc_note, get_last_insn ());
2728 rtx insn, next_insn;
2729 for (insn = start_move; insn; insn = next_insn)
2731 /* Figure out which insn comes after this one. We have
2732 to do this before we move INSN. */
2733 next_insn = (insn == etc_note ? NULL : NEXT_INSN (insn));
2735 if (GET_CODE (insn) == NOTE
2736 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
2737 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
2740 reorder_insns (insn, insn, get_last_insn ());
2744 /* Add the jump from the top of the loop. */
2745 emit_jump_insn_before (gen_jump (start_label), top_label);
2746 emit_barrier_before (top_label);
2747 start_label = top_label;
2750 emit_jump (start_label);
2751 emit_note (NULL, NOTE_INSN_LOOP_END);
2752 emit_label (loop_stack->data.loop.end_label);
2754 POPSTACK (loop_stack);
2759 /* Finish a null loop, aka do { } while (0). */
2762 expand_end_null_loop ()
2764 do_pending_stack_adjust ();
2765 emit_label (loop_stack->data.loop.end_label);
2767 POPSTACK (loop_stack);
2772 /* Generate a jump to the current loop's continue-point.
2773 This is usually the top of the loop, but may be specified
2774 explicitly elsewhere. If not currently inside a loop,
2775 return 0 and do nothing; caller will print an error message. */
2778 expand_continue_loop (whichloop)
2779 struct nesting *whichloop;
2781 /* Emit information for branch prediction. */
2784 note = emit_note (NULL, NOTE_INSN_PREDICTION);
2785 NOTE_PREDICTION (note) = NOTE_PREDICT (PRED_CONTINUE, IS_TAKEN);
2788 whichloop = loop_stack;
2791 expand_goto_internal (NULL_TREE, whichloop->data.loop.continue_label,
2796 /* Generate a jump to exit the current loop. If not currently inside a loop,
2797 return 0 and do nothing; caller will print an error message. */
2800 expand_exit_loop (whichloop)
2801 struct nesting *whichloop;
2805 whichloop = loop_stack;
2808 expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label, NULL_RTX);
2812 /* Generate a conditional jump to exit the current loop if COND
2813 evaluates to zero. If not currently inside a loop,
2814 return 0 and do nothing; caller will print an error message. */
2817 expand_exit_loop_if_false (whichloop, cond)
2818 struct nesting *whichloop;
2825 whichloop = loop_stack;
2829 if (integer_nonzerop (cond))
2831 if (integer_zerop (cond))
2832 return expand_exit_loop (whichloop);
2834 /* Check if we definitely won't need a fixup. */
2835 if (whichloop == nesting_stack)
2837 jumpifnot (cond, whichloop->data.loop.end_label);
2841 /* In order to handle fixups, we actually create a conditional jump
2842 around an unconditional branch to exit the loop. If fixups are
2843 necessary, they go before the unconditional branch. */
2845 label = gen_label_rtx ();
2846 jumpif (cond, label);
2847 expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label,
2854 /* Like expand_exit_loop_if_false except also emit a note marking
2855 the end of the conditional. Should only be used immediately
2856 after expand_loop_start. */
2859 expand_exit_loop_top_cond (whichloop, cond)
2860 struct nesting *whichloop;
2863 if (! expand_exit_loop_if_false (whichloop, cond))
2866 emit_note (NULL, NOTE_INSN_LOOP_END_TOP_COND);
2870 /* Return nonzero if we should preserve sub-expressions as separate
2871 pseudos. We never do so if we aren't optimizing. We always do so
2872 if -fexpensive-optimizations.
2874 Otherwise, we only do so if we are in the "early" part of a loop. I.e.,
2875 the loop may still be a small one. */
2878 preserve_subexpressions_p ()
2882 if (flag_expensive_optimizations)
2885 if (optimize == 0 || cfun == 0 || cfun->stmt == 0 || loop_stack == 0)
2888 insn = get_last_insn_anywhere ();
2891 && (INSN_UID (insn) - INSN_UID (loop_stack->data.loop.start_label)
2892 < n_non_fixed_regs * 3));
2896 /* Generate a jump to exit the current loop, conditional, binding contour
2897 or case statement. Not all such constructs are visible to this function,
2898 only those started with EXIT_FLAG nonzero. Individual languages use
2899 the EXIT_FLAG parameter to control which kinds of constructs you can
2902 If not currently inside anything that can be exited,
2903 return 0 and do nothing; caller will print an error message. */
2906 expand_exit_something ()
2910 for (n = nesting_stack; n; n = n->all)
2911 if (n->exit_label != 0)
2913 expand_goto_internal (NULL_TREE, n->exit_label, NULL_RTX);
2920 /* Generate RTL to return from the current function, with no value.
2921 (That is, we do not do anything about returning any value.) */
2924 expand_null_return ()
2928 last_insn = get_last_insn ();
2930 /* If this function was declared to return a value, but we
2931 didn't, clobber the return registers so that they are not
2932 propagated live to the rest of the function. */
2933 clobber_return_register ();
2935 expand_null_return_1 (last_insn);
2938 /* Try to guess whether the value of return means error code. */
2939 static enum br_predictor
2940 return_prediction (val)
2943 /* Different heuristics for pointers and scalars. */
2944 if (POINTER_TYPE_P (TREE_TYPE (DECL_RESULT (current_function_decl))))
2946 /* NULL is usually not returned. */
2947 if (val == const0_rtx)
2948 return PRED_NULL_RETURN;
2952 /* Negative return values are often used to indicate
2954 if (GET_CODE (val) == CONST_INT
2955 && INTVAL (val) < 0)
2956 return PRED_NEGATIVE_RETURN;
2957 /* Constant return values are also usually erors,
2958 zero/one often mean booleans so exclude them from the
2960 if (CONSTANT_P (val)
2961 && (val != const0_rtx && val != const1_rtx))
2962 return PRED_CONST_RETURN;
2964 return PRED_NO_PREDICTION;
2967 /* Generate RTL to return from the current function, with value VAL. */
2970 expand_value_return (val)
2975 enum br_predictor pred;
2977 if ((pred = return_prediction (val)) != PRED_NO_PREDICTION)
2979 /* Emit information for branch prediction. */
2982 note = emit_note (NULL, NOTE_INSN_PREDICTION);
2984 NOTE_PREDICTION (note) = NOTE_PREDICT (pred, NOT_TAKEN);
2988 last_insn = get_last_insn ();
2989 return_reg = DECL_RTL (DECL_RESULT (current_function_decl));
2991 /* Copy the value to the return location
2992 unless it's already there. */
2994 if (return_reg != val)
2996 tree type = TREE_TYPE (DECL_RESULT (current_function_decl));
2997 #ifdef PROMOTE_FUNCTION_RETURN
2998 int unsignedp = TREE_UNSIGNED (type);
2999 enum machine_mode old_mode
3000 = DECL_MODE (DECL_RESULT (current_function_decl));
3001 enum machine_mode mode
3002 = promote_mode (type, old_mode, &unsignedp, 1);
3004 if (mode != old_mode)
3005 val = convert_modes (mode, old_mode, val, unsignedp);
3007 if (GET_CODE (return_reg) == PARALLEL)
3008 emit_group_load (return_reg, val, int_size_in_bytes (type));
3010 emit_move_insn (return_reg, val);
3013 expand_null_return_1 (last_insn);
3016 /* Output a return with no value. If LAST_INSN is nonzero,
3017 pretend that the return takes place after LAST_INSN. */
3020 expand_null_return_1 (last_insn)
3023 rtx end_label = cleanup_label ? cleanup_label : return_label;
3025 clear_pending_stack_adjust ();
3026 do_pending_stack_adjust ();
3030 end_label = return_label = gen_label_rtx ();
3031 expand_goto_internal (NULL_TREE, end_label, last_insn);
3034 /* Generate RTL to evaluate the expression RETVAL and return it
3035 from the current function. */
3038 expand_return (retval)
3041 /* If there are any cleanups to be performed, then they will
3042 be inserted following LAST_INSN. It is desirable
3043 that the last_insn, for such purposes, should be the
3044 last insn before computing the return value. Otherwise, cleanups
3045 which call functions can clobber the return value. */
3046 /* ??? rms: I think that is erroneous, because in C++ it would
3047 run destructors on variables that might be used in the subsequent
3048 computation of the return value. */
3054 /* If function wants no value, give it none. */
3055 if (TREE_CODE (TREE_TYPE (TREE_TYPE (current_function_decl))) == VOID_TYPE)
3057 expand_expr (retval, NULL_RTX, VOIDmode, 0);
3059 expand_null_return ();
3063 if (retval == error_mark_node)
3065 /* Treat this like a return of no value from a function that
3067 expand_null_return ();
3070 else if (TREE_CODE (retval) == RESULT_DECL)
3071 retval_rhs = retval;
3072 else if ((TREE_CODE (retval) == MODIFY_EXPR || TREE_CODE (retval) == INIT_EXPR)
3073 && TREE_CODE (TREE_OPERAND (retval, 0)) == RESULT_DECL)
3074 retval_rhs = TREE_OPERAND (retval, 1);
3075 else if (VOID_TYPE_P (TREE_TYPE (retval)))
3076 /* Recognize tail-recursive call to void function. */
3077 retval_rhs = retval;
3079 retval_rhs = NULL_TREE;
3081 last_insn = get_last_insn ();
3083 /* Distribute return down conditional expr if either of the sides
3084 may involve tail recursion (see test below). This enhances the number
3085 of tail recursions we see. Don't do this always since it can produce
3086 sub-optimal code in some cases and we distribute assignments into
3087 conditional expressions when it would help. */
3089 if (optimize && retval_rhs != 0
3090 && frame_offset == 0
3091 && TREE_CODE (retval_rhs) == COND_EXPR
3092 && (TREE_CODE (TREE_OPERAND (retval_rhs, 1)) == CALL_EXPR
3093 || TREE_CODE (TREE_OPERAND (retval_rhs, 2)) == CALL_EXPR))
3095 rtx label = gen_label_rtx ();
3098 do_jump (TREE_OPERAND (retval_rhs, 0), label, NULL_RTX);
3099 start_cleanup_deferral ();
3100 expr = build (MODIFY_EXPR, TREE_TYPE (TREE_TYPE (current_function_decl)),
3101 DECL_RESULT (current_function_decl),
3102 TREE_OPERAND (retval_rhs, 1));
3103 TREE_SIDE_EFFECTS (expr) = 1;
3104 expand_return (expr);
3107 expr = build (MODIFY_EXPR, TREE_TYPE (TREE_TYPE (current_function_decl)),
3108 DECL_RESULT (current_function_decl),
3109 TREE_OPERAND (retval_rhs, 2));
3110 TREE_SIDE_EFFECTS (expr) = 1;
3111 expand_return (expr);
3112 end_cleanup_deferral ();
3116 result_rtl = DECL_RTL (DECL_RESULT (current_function_decl));
3118 /* If the result is an aggregate that is being returned in one (or more)
3119 registers, load the registers here. The compiler currently can't handle
3120 copying a BLKmode value into registers. We could put this code in a
3121 more general area (for use by everyone instead of just function
3122 call/return), but until this feature is generally usable it is kept here
3123 (and in expand_call). The value must go into a pseudo in case there
3124 are cleanups that will clobber the real return register. */
3127 && TYPE_MODE (TREE_TYPE (retval_rhs)) == BLKmode
3128 && GET_CODE (result_rtl) == REG)
3131 unsigned HOST_WIDE_INT bitpos, xbitpos;
3132 unsigned HOST_WIDE_INT big_endian_correction = 0;
3133 unsigned HOST_WIDE_INT bytes
3134 = int_size_in_bytes (TREE_TYPE (retval_rhs));
3135 int n_regs = (bytes + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
3136 unsigned int bitsize
3137 = MIN (TYPE_ALIGN (TREE_TYPE (retval_rhs)), BITS_PER_WORD);
3138 rtx *result_pseudos = (rtx *) alloca (sizeof (rtx) * n_regs);
3139 rtx result_reg, src = NULL_RTX, dst = NULL_RTX;
3140 rtx result_val = expand_expr (retval_rhs, NULL_RTX, VOIDmode, 0);
3141 enum machine_mode tmpmode, result_reg_mode;
3145 expand_null_return ();
3149 /* Structures whose size is not a multiple of a word are aligned
3150 to the least significant byte (to the right). On a BYTES_BIG_ENDIAN
3151 machine, this means we must skip the empty high order bytes when
3152 calculating the bit offset. */
3153 if (BYTES_BIG_ENDIAN
3154 && bytes % UNITS_PER_WORD)
3155 big_endian_correction = (BITS_PER_WORD - ((bytes % UNITS_PER_WORD)
3158 /* Copy the structure BITSIZE bits at a time. */
3159 for (bitpos = 0, xbitpos = big_endian_correction;
3160 bitpos < bytes * BITS_PER_UNIT;
3161 bitpos += bitsize, xbitpos += bitsize)
3163 /* We need a new destination pseudo each time xbitpos is
3164 on a word boundary and when xbitpos == big_endian_correction
3165 (the first time through). */
3166 if (xbitpos % BITS_PER_WORD == 0
3167 || xbitpos == big_endian_correction)
3169 /* Generate an appropriate register. */
3170 dst = gen_reg_rtx (word_mode);
3171 result_pseudos[xbitpos / BITS_PER_WORD] = dst;
3173 /* Clear the destination before we move anything into it. */
3174 emit_move_insn (dst, CONST0_RTX (GET_MODE (dst)));
3177 /* We need a new source operand each time bitpos is on a word
3179 if (bitpos % BITS_PER_WORD == 0)
3180 src = operand_subword_force (result_val,
3181 bitpos / BITS_PER_WORD,
3184 /* Use bitpos for the source extraction (left justified) and
3185 xbitpos for the destination store (right justified). */
3186 store_bit_field (dst, bitsize, xbitpos % BITS_PER_WORD, word_mode,
3187 extract_bit_field (src, bitsize,
3188 bitpos % BITS_PER_WORD, 1,
3189 NULL_RTX, word_mode, word_mode,
3194 /* Find the smallest integer mode large enough to hold the
3195 entire structure and use that mode instead of BLKmode
3196 on the USE insn for the return register. */
3197 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
3198 tmpmode != VOIDmode;
3199 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
3200 /* Have we found a large enough mode? */
3201 if (GET_MODE_SIZE (tmpmode) >= bytes)
3204 /* No suitable mode found. */
3205 if (tmpmode == VOIDmode)
3208 PUT_MODE (result_rtl, tmpmode);
3210 if (GET_MODE_SIZE (tmpmode) < GET_MODE_SIZE (word_mode))
3211 result_reg_mode = word_mode;
3213 result_reg_mode = tmpmode;
3214 result_reg = gen_reg_rtx (result_reg_mode);
3217 for (i = 0; i < n_regs; i++)
3218 emit_move_insn (operand_subword (result_reg, i, 0, result_reg_mode),
3221 if (tmpmode != result_reg_mode)
3222 result_reg = gen_lowpart (tmpmode, result_reg);
3224 expand_value_return (result_reg);
3226 else if (retval_rhs != 0
3227 && !VOID_TYPE_P (TREE_TYPE (retval_rhs))
3228 && (GET_CODE (result_rtl) == REG
3229 || (GET_CODE (result_rtl) == PARALLEL)))
3231 /* Calculate the return value into a temporary (usually a pseudo
3233 tree ot = TREE_TYPE (DECL_RESULT (current_function_decl));
3234 tree nt = build_qualified_type (ot, TYPE_QUALS (ot) | TYPE_QUAL_CONST);
3236 val = assign_temp (nt, 0, 0, 1);
3237 val = expand_expr (retval_rhs, val, GET_MODE (val), 0);
3238 val = force_not_mem (val);
3240 /* Return the calculated value, doing cleanups first. */
3241 expand_value_return (val);
3245 /* No cleanups or no hard reg used;
3246 calculate value into hard return reg. */
3247 expand_expr (retval, const0_rtx, VOIDmode, 0);
3249 expand_value_return (result_rtl);
3253 /* Attempt to optimize a potential tail recursion call into a goto.
3254 ARGUMENTS are the arguments to a CALL_EXPR; LAST_INSN indicates
3255 where to place the jump to the tail recursion label.
3257 Return TRUE if the call was optimized into a goto. */
3260 optimize_tail_recursion (arguments, last_insn)
3264 /* Finish checking validity, and if valid emit code to set the
3265 argument variables for the new call. */
3266 if (tail_recursion_args (arguments, DECL_ARGUMENTS (current_function_decl)))
3268 if (tail_recursion_label == 0)
3270 tail_recursion_label = gen_label_rtx ();
3271 emit_label_after (tail_recursion_label,
3272 tail_recursion_reentry);
3275 expand_goto_internal (NULL_TREE, tail_recursion_label, last_insn);
3282 /* Emit code to alter this function's formal parms for a tail-recursive call.
3283 ACTUALS is a list of actual parameter expressions (chain of TREE_LISTs).
3284 FORMALS is the chain of decls of formals.
3285 Return 1 if this can be done;
3286 otherwise return 0 and do not emit any code. */
3289 tail_recursion_args (actuals, formals)
3290 tree actuals, formals;
3292 tree a = actuals, f = formals;
3296 /* Check that number and types of actuals are compatible
3297 with the formals. This is not always true in valid C code.
3298 Also check that no formal needs to be addressable
3299 and that all formals are scalars. */
3301 /* Also count the args. */
3303 for (a = actuals, f = formals, i = 0; a && f; a = TREE_CHAIN (a), f = TREE_CHAIN (f), i++)
3305 if (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_VALUE (a)))
3306 != TYPE_MAIN_VARIANT (TREE_TYPE (f)))
3308 if (GET_CODE (DECL_RTL (f)) != REG || DECL_MODE (f) == BLKmode)
3311 if (a != 0 || f != 0)
3314 /* Compute all the actuals. */
3316 argvec = (rtx *) alloca (i * sizeof (rtx));
3318 for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
3319 argvec[i] = expand_expr (TREE_VALUE (a), NULL_RTX, VOIDmode, 0);
3321 /* Find which actual values refer to current values of previous formals.
3322 Copy each of them now, before any formal is changed. */
3324 for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
3328 for (f = formals, j = 0; j < i; f = TREE_CHAIN (f), j++)
3329 if (reg_mentioned_p (DECL_RTL (f), argvec[i]))
3335 argvec[i] = copy_to_reg (argvec[i]);
3338 /* Store the values of the actuals into the formals. */
3340 for (f = formals, a = actuals, i = 0; f;
3341 f = TREE_CHAIN (f), a = TREE_CHAIN (a), i++)
3343 if (GET_MODE (DECL_RTL (f)) == GET_MODE (argvec[i]))
3344 emit_move_insn (DECL_RTL (f), argvec[i]);
3347 rtx tmp = argvec[i];
3349 if (DECL_MODE (f) != GET_MODE (DECL_RTL (f)))
3351 tmp = gen_reg_rtx (DECL_MODE (f));
3352 convert_move (tmp, argvec[i],
3353 TREE_UNSIGNED (TREE_TYPE (TREE_VALUE (a))));
3355 convert_move (DECL_RTL (f), tmp,
3356 TREE_UNSIGNED (TREE_TYPE (TREE_VALUE (a))));
3364 /* Generate the RTL code for entering a binding contour.
3365 The variables are declared one by one, by calls to `expand_decl'.
3367 FLAGS is a bitwise or of the following flags:
3369 1 - Nonzero if this construct should be visible to
3372 2 - Nonzero if this contour does not require a
3373 NOTE_INSN_BLOCK_BEG note. Virtually all calls from
3374 language-independent code should set this flag because they
3375 will not create corresponding BLOCK nodes. (There should be
3376 a one-to-one correspondence between NOTE_INSN_BLOCK_BEG notes
3377 and BLOCKs.) If this flag is set, MARK_ENDS should be zero
3378 when expand_end_bindings is called.
3380 If we are creating a NOTE_INSN_BLOCK_BEG note, a BLOCK may
3381 optionally be supplied. If so, it becomes the NOTE_BLOCK for the
3385 expand_start_bindings_and_block (flags, block)
3389 struct nesting *thisblock = ALLOC_NESTING ();
3391 int exit_flag = ((flags & 1) != 0);
3392 int block_flag = ((flags & 2) == 0);
3394 /* If a BLOCK is supplied, then the caller should be requesting a
3395 NOTE_INSN_BLOCK_BEG note. */
3396 if (!block_flag && block)
3399 /* Create a note to mark the beginning of the block. */
3402 note = emit_note (NULL, NOTE_INSN_BLOCK_BEG);
3403 NOTE_BLOCK (note) = block;
3406 note = emit_note (NULL, NOTE_INSN_DELETED);
3408 /* Make an entry on block_stack for the block we are entering. */
3410 thisblock->desc = BLOCK_NESTING;
3411 thisblock->next = block_stack;
3412 thisblock->all = nesting_stack;
3413 thisblock->depth = ++nesting_depth;
3414 thisblock->data.block.stack_level = 0;
3415 thisblock->data.block.cleanups = 0;
3416 thisblock->data.block.n_function_calls = 0;
3417 thisblock->data.block.exception_region = 0;
3418 thisblock->data.block.block_target_temp_slot_level = target_temp_slot_level;
3420 thisblock->data.block.conditional_code = 0;
3421 thisblock->data.block.last_unconditional_cleanup = note;
3422 /* When we insert instructions after the last unconditional cleanup,
3423 we don't adjust last_insn. That means that a later add_insn will
3424 clobber the instructions we've just added. The easiest way to
3425 fix this is to just insert another instruction here, so that the
3426 instructions inserted after the last unconditional cleanup are
3427 never the last instruction. */
3428 emit_note (NULL, NOTE_INSN_DELETED);
3431 && !(block_stack->data.block.cleanups == NULL_TREE
3432 && block_stack->data.block.outer_cleanups == NULL_TREE))
3433 thisblock->data.block.outer_cleanups
3434 = tree_cons (NULL_TREE, block_stack->data.block.cleanups,
3435 block_stack->data.block.outer_cleanups);
3437 thisblock->data.block.outer_cleanups = 0;
3438 thisblock->data.block.label_chain = 0;
3439 thisblock->data.block.innermost_stack_block = stack_block_stack;
3440 thisblock->data.block.first_insn = note;
3441 thisblock->data.block.block_start_count = ++current_block_start_count;
3442 thisblock->exit_label = exit_flag ? gen_label_rtx () : 0;
3443 block_stack = thisblock;
3444 nesting_stack = thisblock;
3446 /* Make a new level for allocating stack slots. */
3450 /* Specify the scope of temporaries created by TARGET_EXPRs. Similar
3451 to CLEANUP_POINT_EXPR, but handles cases when a series of calls to
3452 expand_expr are made. After we end the region, we know that all
3453 space for all temporaries that were created by TARGET_EXPRs will be
3454 destroyed and their space freed for reuse. */
3457 expand_start_target_temps ()
3459 /* This is so that even if the result is preserved, the space
3460 allocated will be freed, as we know that it is no longer in use. */
3463 /* Start a new binding layer that will keep track of all cleanup
3464 actions to be performed. */
3465 expand_start_bindings (2);
3467 target_temp_slot_level = temp_slot_level;
3471 expand_end_target_temps ()
3473 expand_end_bindings (NULL_TREE, 0, 0);
3475 /* This is so that even if the result is preserved, the space
3476 allocated will be freed, as we know that it is no longer in use. */
3480 /* Given a pointer to a BLOCK node return nonzero if (and only if) the node
3481 in question represents the outermost pair of curly braces (i.e. the "body
3482 block") of a function or method.
3484 For any BLOCK node representing a "body block" of a function or method, the
3485 BLOCK_SUPERCONTEXT of the node will point to another BLOCK node which
3486 represents the outermost (function) scope for the function or method (i.e.
3487 the one which includes the formal parameters). The BLOCK_SUPERCONTEXT of
3488 *that* node in turn will point to the relevant FUNCTION_DECL node. */
3491 is_body_block (stmt)
3494 if (TREE_CODE (stmt) == BLOCK)
3496 tree parent = BLOCK_SUPERCONTEXT (stmt);
3498 if (parent && TREE_CODE (parent) == BLOCK)
3500 tree grandparent = BLOCK_SUPERCONTEXT (parent);
3502 if (grandparent && TREE_CODE (grandparent) == FUNCTION_DECL)
3510 /* True if we are currently emitting insns in an area of output code
3511 that is controlled by a conditional expression. This is used by
3512 the cleanup handling code to generate conditional cleanup actions. */
3515 conditional_context ()
3517 return block_stack && block_stack->data.block.conditional_code;
3520 /* Return an opaque pointer to the current nesting level, so frontend code
3521 can check its own sanity. */
3524 current_nesting_level ()
3526 return cfun ? block_stack : 0;
3529 /* Emit a handler label for a nonlocal goto handler.
3530 Also emit code to store the handler label in SLOT before BEFORE_INSN. */
3533 expand_nl_handler_label (slot, before_insn)
3534 rtx slot, before_insn;
3537 rtx handler_label = gen_label_rtx ();
3539 /* Don't let cleanup_cfg delete the handler. */
3540 LABEL_PRESERVE_P (handler_label) = 1;
3543 emit_move_insn (slot, gen_rtx_LABEL_REF (Pmode, handler_label));
3544 insns = get_insns ();
3546 emit_insn_before (insns, before_insn);
3548 emit_label (handler_label);
3550 return handler_label;
3553 /* Emit code to restore vital registers at the beginning of a nonlocal goto
3556 expand_nl_goto_receiver ()
3558 #ifdef HAVE_nonlocal_goto
3559 if (! HAVE_nonlocal_goto)
3561 /* First adjust our frame pointer to its actual value. It was
3562 previously set to the start of the virtual area corresponding to
3563 the stacked variables when we branched here and now needs to be
3564 adjusted to the actual hardware fp value.
3566 Assignments are to virtual registers are converted by
3567 instantiate_virtual_regs into the corresponding assignment
3568 to the underlying register (fp in this case) that makes
3569 the original assignment true.
3570 So the following insn will actually be
3571 decrementing fp by STARTING_FRAME_OFFSET. */
3572 emit_move_insn (virtual_stack_vars_rtx, hard_frame_pointer_rtx);
3574 #if ARG_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3575 if (fixed_regs[ARG_POINTER_REGNUM])
3577 #ifdef ELIMINABLE_REGS
3578 /* If the argument pointer can be eliminated in favor of the
3579 frame pointer, we don't need to restore it. We assume here
3580 that if such an elimination is present, it can always be used.
3581 This is the case on all known machines; if we don't make this
3582 assumption, we do unnecessary saving on many machines. */
3583 static const struct elims {const int from, to;} elim_regs[] = ELIMINABLE_REGS;
3586 for (i = 0; i < ARRAY_SIZE (elim_regs); i++)
3587 if (elim_regs[i].from == ARG_POINTER_REGNUM
3588 && elim_regs[i].to == HARD_FRAME_POINTER_REGNUM)
3591 if (i == ARRAY_SIZE (elim_regs))
3594 /* Now restore our arg pointer from the address at which it
3595 was saved in our stack frame. */
3596 emit_move_insn (virtual_incoming_args_rtx,
3597 copy_to_reg (get_arg_pointer_save_area (cfun)));
3602 #ifdef HAVE_nonlocal_goto_receiver
3603 if (HAVE_nonlocal_goto_receiver)
3604 emit_insn (gen_nonlocal_goto_receiver ());
3608 /* Make handlers for nonlocal gotos taking place in the function calls in
3612 expand_nl_goto_receivers (thisblock)
3613 struct nesting *thisblock;
3616 rtx afterward = gen_label_rtx ();
3621 /* Record the handler address in the stack slot for that purpose,
3622 during this block, saving and restoring the outer value. */
3623 if (thisblock->next != 0)
3624 for (slot = nonlocal_goto_handler_slots; slot; slot = XEXP (slot, 1))
3626 rtx save_receiver = gen_reg_rtx (Pmode);
3627 emit_move_insn (XEXP (slot, 0), save_receiver);
3630 emit_move_insn (save_receiver, XEXP (slot, 0));
3631 insns = get_insns ();
3633 emit_insn_before (insns, thisblock->data.block.first_insn);
3636 /* Jump around the handlers; they run only when specially invoked. */
3637 emit_jump (afterward);
3639 /* Make a separate handler for each label. */
3640 link = nonlocal_labels;
3641 slot = nonlocal_goto_handler_slots;
3642 label_list = NULL_RTX;
3643 for (; link; link = TREE_CHAIN (link), slot = XEXP (slot, 1))
3644 /* Skip any labels we shouldn't be able to jump to from here,
3645 we generate one special handler for all of them below which just calls
3647 if (! DECL_TOO_LATE (TREE_VALUE (link)))
3650 lab = expand_nl_handler_label (XEXP (slot, 0),
3651 thisblock->data.block.first_insn);
3652 label_list = gen_rtx_EXPR_LIST (VOIDmode, lab, label_list);
3654 expand_nl_goto_receiver ();
3656 /* Jump to the "real" nonlocal label. */
3657 expand_goto (TREE_VALUE (link));
3660 /* A second pass over all nonlocal labels; this time we handle those
3661 we should not be able to jump to at this point. */
3662 link = nonlocal_labels;
3663 slot = nonlocal_goto_handler_slots;
3665 for (; link; link = TREE_CHAIN (link), slot = XEXP (slot, 1))
3666 if (DECL_TOO_LATE (TREE_VALUE (link)))
3669 lab = expand_nl_handler_label (XEXP (slot, 0),
3670 thisblock->data.block.first_insn);
3671 label_list = gen_rtx_EXPR_LIST (VOIDmode, lab, label_list);
3677 expand_nl_goto_receiver ();
3678 expand_builtin_trap ();
3681 nonlocal_goto_handler_labels = label_list;
3682 emit_label (afterward);
3685 /* Warn about any unused VARS (which may contain nodes other than
3686 VAR_DECLs, but such nodes are ignored). The nodes are connected
3687 via the TREE_CHAIN field. */
3690 warn_about_unused_variables (vars)
3695 if (warn_unused_variable)
3696 for (decl = vars; decl; decl = TREE_CHAIN (decl))
3697 if (TREE_CODE (decl) == VAR_DECL
3698 && ! TREE_USED (decl)
3699 && ! DECL_IN_SYSTEM_HEADER (decl)
3700 && DECL_NAME (decl) && ! DECL_ARTIFICIAL (decl))
3701 warning_with_decl (decl, "unused variable `%s'");
3704 /* Generate RTL code to terminate a binding contour.
3706 VARS is the chain of VAR_DECL nodes for the variables bound in this
3707 contour. There may actually be other nodes in this chain, but any
3708 nodes other than VAR_DECLS are ignored.
3710 MARK_ENDS is nonzero if we should put a note at the beginning
3711 and end of this binding contour.
3713 DONT_JUMP_IN is nonzero if it is not valid to jump into this contour.
3714 (That is true automatically if the contour has a saved stack level.) */
3717 expand_end_bindings (vars, mark_ends, dont_jump_in)
3722 struct nesting *thisblock = block_stack;
3724 /* If any of the variables in this scope were not used, warn the
3726 warn_about_unused_variables (vars);
3728 if (thisblock->exit_label)
3730 do_pending_stack_adjust ();
3731 emit_label (thisblock->exit_label);
3734 /* If necessary, make handlers for nonlocal gotos taking
3735 place in the function calls in this block. */
3736 if (function_call_count != thisblock->data.block.n_function_calls
3738 /* Make handler for outermost block
3739 if there were any nonlocal gotos to this function. */
3740 && (thisblock->next == 0 ? current_function_has_nonlocal_label
3741 /* Make handler for inner block if it has something
3742 special to do when you jump out of it. */
3743 : (thisblock->data.block.cleanups != 0
3744 || thisblock->data.block.stack_level != 0)))
3745 expand_nl_goto_receivers (thisblock);
3747 /* Don't allow jumping into a block that has a stack level.
3748 Cleanups are allowed, though. */
3750 || thisblock->data.block.stack_level != 0)
3752 struct label_chain *chain;
3754 /* Any labels in this block are no longer valid to go to.
3755 Mark them to cause an error message. */
3756 for (chain = thisblock->data.block.label_chain; chain; chain = chain->next)
3758 DECL_TOO_LATE (chain->label) = 1;
3759 /* If any goto without a fixup came to this label,
3760 that must be an error, because gotos without fixups
3761 come from outside all saved stack-levels. */
3762 if (TREE_ADDRESSABLE (chain->label))
3763 error_with_decl (chain->label,
3764 "label `%s' used before containing binding contour");
3768 /* Restore stack level in effect before the block
3769 (only if variable-size objects allocated). */
3770 /* Perform any cleanups associated with the block. */
3772 if (thisblock->data.block.stack_level != 0
3773 || thisblock->data.block.cleanups != 0)
3778 /* Don't let cleanups affect ({...}) constructs. */
3779 int old_expr_stmts_for_value = expr_stmts_for_value;
3780 rtx old_last_expr_value = last_expr_value;
3781 tree old_last_expr_type = last_expr_type;
3782 expr_stmts_for_value = 0;
3784 /* Only clean up here if this point can actually be reached. */
3785 insn = get_last_insn ();
3786 if (GET_CODE (insn) == NOTE)
3787 insn = prev_nonnote_insn (insn);
3788 reachable = (! insn || GET_CODE (insn) != BARRIER);
3790 /* Do the cleanups. */
3791 expand_cleanups (thisblock->data.block.cleanups, NULL_TREE, 0, reachable);
3793 do_pending_stack_adjust ();
3795 expr_stmts_for_value = old_expr_stmts_for_value;
3796 last_expr_value = old_last_expr_value;
3797 last_expr_type = old_last_expr_type;
3799 /* Restore the stack level. */
3801 if (reachable && thisblock->data.block.stack_level != 0)
3803 emit_stack_restore (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3804 thisblock->data.block.stack_level, NULL_RTX);
3805 if (nonlocal_goto_handler_slots != 0)
3806 emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level,
3810 /* Any gotos out of this block must also do these things.
3811 Also report any gotos with fixups that came to labels in this
3813 fixup_gotos (thisblock,
3814 thisblock->data.block.stack_level,
3815 thisblock->data.block.cleanups,
3816 thisblock->data.block.first_insn,
3820 /* Mark the beginning and end of the scope if requested.
3821 We do this now, after running cleanups on the variables
3822 just going out of scope, so they are in scope for their cleanups. */
3826 rtx note = emit_note (NULL, NOTE_INSN_BLOCK_END);
3827 NOTE_BLOCK (note) = NOTE_BLOCK (thisblock->data.block.first_insn);
3830 /* Get rid of the beginning-mark if we don't make an end-mark. */
3831 NOTE_LINE_NUMBER (thisblock->data.block.first_insn) = NOTE_INSN_DELETED;
3833 /* Restore the temporary level of TARGET_EXPRs. */
3834 target_temp_slot_level = thisblock->data.block.block_target_temp_slot_level;
3836 /* Restore block_stack level for containing block. */
3838 stack_block_stack = thisblock->data.block.innermost_stack_block;
3839 POPSTACK (block_stack);
3841 /* Pop the stack slot nesting and free any slots at this level. */
3845 /* Generate code to save the stack pointer at the start of the current block
3846 and set up to restore it on exit. */
3849 save_stack_pointer ()
3851 struct nesting *thisblock = block_stack;
3853 if (thisblock->data.block.stack_level == 0)
3855 emit_stack_save (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3856 &thisblock->data.block.stack_level,
3857 thisblock->data.block.first_insn);
3858 stack_block_stack = thisblock;
3862 /* Generate RTL for the automatic variable declaration DECL.
3863 (Other kinds of declarations are simply ignored if seen here.) */
3871 type = TREE_TYPE (decl);
3873 /* For a CONST_DECL, set mode, alignment, and sizes from those of the
3874 type in case this node is used in a reference. */
3875 if (TREE_CODE (decl) == CONST_DECL)
3877 DECL_MODE (decl) = TYPE_MODE (type);
3878 DECL_ALIGN (decl) = TYPE_ALIGN (type);
3879 DECL_SIZE (decl) = TYPE_SIZE (type);
3880 DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (type);
3884 /* Otherwise, only automatic variables need any expansion done. Static and
3885 external variables, and external functions, will be handled by
3886 `assemble_variable' (called from finish_decl). TYPE_DECL requires
3887 nothing. PARM_DECLs are handled in `assign_parms'. */
3888 if (TREE_CODE (decl) != VAR_DECL)
3891 if (TREE_STATIC (decl) || DECL_EXTERNAL (decl))
3894 /* Create the RTL representation for the variable. */
3896 if (type == error_mark_node)
3897 SET_DECL_RTL (decl, gen_rtx_MEM (BLKmode, const0_rtx));
3899 else if (DECL_SIZE (decl) == 0)
3900 /* Variable with incomplete type. */
3903 if (DECL_INITIAL (decl) == 0)
3904 /* Error message was already done; now avoid a crash. */
3905 x = gen_rtx_MEM (BLKmode, const0_rtx);
3907 /* An initializer is going to decide the size of this array.
3908 Until we know the size, represent its address with a reg. */
3909 x = gen_rtx_MEM (BLKmode, gen_reg_rtx (Pmode));
3911 set_mem_attributes (x, decl, 1);
3912 SET_DECL_RTL (decl, x);
3914 else if (DECL_MODE (decl) != BLKmode
3915 /* If -ffloat-store, don't put explicit float vars
3917 && !(flag_float_store
3918 && TREE_CODE (type) == REAL_TYPE)
3919 && ! TREE_THIS_VOLATILE (decl)
3920 && (DECL_REGISTER (decl) || optimize))
3922 /* Automatic variable that can go in a register. */
3923 int unsignedp = TREE_UNSIGNED (type);
3924 enum machine_mode reg_mode
3925 = promote_mode (type, DECL_MODE (decl), &unsignedp, 0);
3927 SET_DECL_RTL (decl, gen_reg_rtx (reg_mode));
3929 mark_user_reg (DECL_RTL (decl));
3931 if (POINTER_TYPE_P (type))
3932 mark_reg_pointer (DECL_RTL (decl),
3933 TYPE_ALIGN (TREE_TYPE (TREE_TYPE (decl))));
3935 maybe_set_unchanging (DECL_RTL (decl), decl);
3937 /* If something wants our address, try to use ADDRESSOF. */
3938 if (TREE_ADDRESSABLE (decl))
3939 put_var_into_stack (decl);
3942 else if (TREE_CODE (DECL_SIZE_UNIT (decl)) == INTEGER_CST
3943 && ! (flag_stack_check && ! STACK_CHECK_BUILTIN
3944 && 0 < compare_tree_int (DECL_SIZE_UNIT (decl),
3945 STACK_CHECK_MAX_VAR_SIZE)))
3947 /* Variable of fixed size that goes on the stack. */
3952 /* If we previously made RTL for this decl, it must be an array
3953 whose size was determined by the initializer.
3954 The old address was a register; set that register now
3955 to the proper address. */
3956 if (DECL_RTL_SET_P (decl))
3958 if (GET_CODE (DECL_RTL (decl)) != MEM
3959 || GET_CODE (XEXP (DECL_RTL (decl), 0)) != REG)
3961 oldaddr = XEXP (DECL_RTL (decl), 0);
3964 /* Set alignment we actually gave this decl. */
3965 DECL_ALIGN (decl) = (DECL_MODE (decl) == BLKmode ? BIGGEST_ALIGNMENT
3966 : GET_MODE_BITSIZE (DECL_MODE (decl)));
3967 DECL_USER_ALIGN (decl) = 0;
3969 x = assign_temp (decl, 1, 1, 1);
3970 set_mem_attributes (x, decl, 1);
3971 SET_DECL_RTL (decl, x);
3975 addr = force_operand (XEXP (DECL_RTL (decl), 0), oldaddr);
3976 if (addr != oldaddr)
3977 emit_move_insn (oldaddr, addr);
3981 /* Dynamic-size object: must push space on the stack. */
3983 rtx address, size, x;
3985 /* Record the stack pointer on entry to block, if have
3986 not already done so. */
3987 do_pending_stack_adjust ();
3988 save_stack_pointer ();
3990 /* In function-at-a-time mode, variable_size doesn't expand this,
3992 if (TREE_CODE (type) == ARRAY_TYPE && TYPE_DOMAIN (type))
3993 expand_expr (TYPE_MAX_VALUE (TYPE_DOMAIN (type)),
3994 const0_rtx, VOIDmode, 0);
3996 /* Compute the variable's size, in bytes. */
3997 size = expand_expr (DECL_SIZE_UNIT (decl), NULL_RTX, VOIDmode, 0);
4000 /* Allocate space on the stack for the variable. Note that
4001 DECL_ALIGN says how the variable is to be aligned and we
4002 cannot use it to conclude anything about the alignment of
4004 address = allocate_dynamic_stack_space (size, NULL_RTX,
4005 TYPE_ALIGN (TREE_TYPE (decl)));
4007 /* Reference the variable indirect through that rtx. */
4008 x = gen_rtx_MEM (DECL_MODE (decl), address);
4009 set_mem_attributes (x, decl, 1);
4010 SET_DECL_RTL (decl, x);
4013 /* Indicate the alignment we actually gave this variable. */
4014 #ifdef STACK_BOUNDARY
4015 DECL_ALIGN (decl) = STACK_BOUNDARY;
4017 DECL_ALIGN (decl) = BIGGEST_ALIGNMENT;
4019 DECL_USER_ALIGN (decl) = 0;
4023 /* Emit code to perform the initialization of a declaration DECL. */
4026 expand_decl_init (decl)
4029 int was_used = TREE_USED (decl);
4031 /* If this is a CONST_DECL, we don't have to generate any code. Likewise
4032 for static decls. */
4033 if (TREE_CODE (decl) == CONST_DECL
4034 || TREE_STATIC (decl))
4037 /* Compute and store the initial value now. */
4039 if (DECL_INITIAL (decl) == error_mark_node)
4041 enum tree_code code = TREE_CODE (TREE_TYPE (decl));
4043 if (code == INTEGER_TYPE || code == REAL_TYPE || code == ENUMERAL_TYPE
4044 || code == POINTER_TYPE || code == REFERENCE_TYPE)
4045 expand_assignment (decl, convert (TREE_TYPE (decl), integer_zero_node),
4049 else if (DECL_INITIAL (decl) && TREE_CODE (DECL_INITIAL (decl)) != TREE_LIST)
4051 emit_line_note (DECL_SOURCE_FILE (decl), DECL_SOURCE_LINE (decl));
4052 expand_assignment (decl, DECL_INITIAL (decl), 0, 0);
4056 /* Don't let the initialization count as "using" the variable. */
4057 TREE_USED (decl) = was_used;
4059 /* Free any temporaries we made while initializing the decl. */
4060 preserve_temp_slots (NULL_RTX);
4064 /* CLEANUP is an expression to be executed at exit from this binding contour;
4065 for example, in C++, it might call the destructor for this variable.
4067 We wrap CLEANUP in an UNSAVE_EXPR node, so that we can expand the
4068 CLEANUP multiple times, and have the correct semantics. This
4069 happens in exception handling, for gotos, returns, breaks that
4070 leave the current scope.
4072 If CLEANUP is nonzero and DECL is zero, we record a cleanup
4073 that is not associated with any particular variable. */
4076 expand_decl_cleanup (decl, cleanup)
4079 struct nesting *thisblock;
4081 /* Error if we are not in any block. */
4082 if (cfun == 0 || block_stack == 0)
4085 thisblock = block_stack;
4087 /* Record the cleanup if there is one. */
4093 tree *cleanups = &thisblock->data.block.cleanups;
4094 int cond_context = conditional_context ();
4098 rtx flag = gen_reg_rtx (word_mode);
4103 emit_move_insn (flag, const0_rtx);
4104 set_flag_0 = get_insns ();
4107 thisblock->data.block.last_unconditional_cleanup
4108 = emit_insn_after (set_flag_0,
4109 thisblock->data.block.last_unconditional_cleanup);
4111 emit_move_insn (flag, const1_rtx);
4113 cond = build_decl (VAR_DECL, NULL_TREE,
4114 (*lang_hooks.types.type_for_mode) (word_mode, 1));
4115 SET_DECL_RTL (cond, flag);
4117 /* Conditionalize the cleanup. */
4118 cleanup = build (COND_EXPR, void_type_node,
4119 (*lang_hooks.truthvalue_conversion) (cond),
4120 cleanup, integer_zero_node);
4121 cleanup = fold (cleanup);
4123 cleanups = &thisblock->data.block.cleanups;
4126 cleanup = unsave_expr (cleanup);
4128 t = *cleanups = tree_cons (decl, cleanup, *cleanups);
4131 /* If this block has a cleanup, it belongs in stack_block_stack. */
4132 stack_block_stack = thisblock;
4139 if (! using_eh_for_cleanups_p)
4140 TREE_ADDRESSABLE (t) = 1;
4142 expand_eh_region_start ();
4149 thisblock->data.block.last_unconditional_cleanup
4150 = emit_insn_after (seq,
4151 thisblock->data.block.last_unconditional_cleanup);
4155 thisblock->data.block.last_unconditional_cleanup
4157 /* When we insert instructions after the last unconditional cleanup,
4158 we don't adjust last_insn. That means that a later add_insn will
4159 clobber the instructions we've just added. The easiest way to
4160 fix this is to just insert another instruction here, so that the
4161 instructions inserted after the last unconditional cleanup are
4162 never the last instruction. */
4163 emit_note (NULL, NOTE_INSN_DELETED);
4169 /* Like expand_decl_cleanup, but maybe only run the cleanup if an exception
4173 expand_decl_cleanup_eh (decl, cleanup, eh_only)
4177 int ret = expand_decl_cleanup (decl, cleanup);
4180 tree node = block_stack->data.block.cleanups;
4181 CLEANUP_EH_ONLY (node) = eh_only;
4186 /* DECL is an anonymous union. CLEANUP is a cleanup for DECL.
4187 DECL_ELTS is the list of elements that belong to DECL's type.
4188 In each, the TREE_VALUE is a VAR_DECL, and the TREE_PURPOSE a cleanup. */
4191 expand_anon_union_decl (decl, cleanup, decl_elts)
4192 tree decl, cleanup, decl_elts;
4194 struct nesting *thisblock = cfun == 0 ? 0 : block_stack;
4198 /* If any of the elements are addressable, so is the entire union. */
4199 for (t = decl_elts; t; t = TREE_CHAIN (t))
4200 if (TREE_ADDRESSABLE (TREE_VALUE (t)))
4202 TREE_ADDRESSABLE (decl) = 1;
4207 expand_decl_cleanup (decl, cleanup);
4208 x = DECL_RTL (decl);
4210 /* Go through the elements, assigning RTL to each. */
4211 for (t = decl_elts; t; t = TREE_CHAIN (t))
4213 tree decl_elt = TREE_VALUE (t);
4214 tree cleanup_elt = TREE_PURPOSE (t);
4215 enum machine_mode mode = TYPE_MODE (TREE_TYPE (decl_elt));
4217 /* If any of the elements are addressable, so is the entire
4219 if (TREE_USED (decl_elt))
4220 TREE_USED (decl) = 1;
4222 /* Propagate the union's alignment to the elements. */
4223 DECL_ALIGN (decl_elt) = DECL_ALIGN (decl);
4224 DECL_USER_ALIGN (decl_elt) = DECL_USER_ALIGN (decl);
4226 /* If the element has BLKmode and the union doesn't, the union is
4227 aligned such that the element doesn't need to have BLKmode, so
4228 change the element's mode to the appropriate one for its size. */
4229 if (mode == BLKmode && DECL_MODE (decl) != BLKmode)
4230 DECL_MODE (decl_elt) = mode
4231 = mode_for_size_tree (DECL_SIZE (decl_elt), MODE_INT, 1);
4233 /* (SUBREG (MEM ...)) at RTL generation time is invalid, so we
4234 instead create a new MEM rtx with the proper mode. */
4235 if (GET_CODE (x) == MEM)
4237 if (mode == GET_MODE (x))
4238 SET_DECL_RTL (decl_elt, x);
4240 SET_DECL_RTL (decl_elt, adjust_address_nv (x, mode, 0));
4242 else if (GET_CODE (x) == REG)
4244 if (mode == GET_MODE (x))
4245 SET_DECL_RTL (decl_elt, x);
4247 SET_DECL_RTL (decl_elt, gen_lowpart_SUBREG (mode, x));
4252 /* Record the cleanup if there is one. */
4255 thisblock->data.block.cleanups
4256 = tree_cons (decl_elt, cleanup_elt,
4257 thisblock->data.block.cleanups);
4261 /* Expand a list of cleanups LIST.
4262 Elements may be expressions or may be nested lists.
4264 If DONT_DO is nonnull, then any list-element
4265 whose TREE_PURPOSE matches DONT_DO is omitted.
4266 This is sometimes used to avoid a cleanup associated with
4267 a value that is being returned out of the scope.
4269 If IN_FIXUP is nonzero, we are generating this cleanup for a fixup
4270 goto and handle protection regions specially in that case.
4272 If REACHABLE, we emit code, otherwise just inform the exception handling
4273 code about this finalization. */
4276 expand_cleanups (list, dont_do, in_fixup, reachable)
4283 for (tail = list; tail; tail = TREE_CHAIN (tail))
4284 if (dont_do == 0 || TREE_PURPOSE (tail) != dont_do)
4286 if (TREE_CODE (TREE_VALUE (tail)) == TREE_LIST)
4287 expand_cleanups (TREE_VALUE (tail), dont_do, in_fixup, reachable);
4290 if (! in_fixup && using_eh_for_cleanups_p)
4291 expand_eh_region_end_cleanup (TREE_VALUE (tail));
4293 if (reachable && !CLEANUP_EH_ONLY (tail))
4295 /* Cleanups may be run multiple times. For example,
4296 when exiting a binding contour, we expand the
4297 cleanups associated with that contour. When a goto
4298 within that binding contour has a target outside that
4299 contour, it will expand all cleanups from its scope to
4300 the target. Though the cleanups are expanded multiple
4301 times, the control paths are non-overlapping so the
4302 cleanups will not be executed twice. */
4304 /* We may need to protect from outer cleanups. */
4305 if (in_fixup && using_eh_for_cleanups_p)
4307 expand_eh_region_start ();
4309 expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0);
4311 expand_eh_region_end_fixup (TREE_VALUE (tail));
4314 expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0);
4322 /* Mark when the context we are emitting RTL for as a conditional
4323 context, so that any cleanup actions we register with
4324 expand_decl_init will be properly conditionalized when those
4325 cleanup actions are later performed. Must be called before any
4326 expression (tree) is expanded that is within a conditional context. */
4329 start_cleanup_deferral ()
4331 /* block_stack can be NULL if we are inside the parameter list. It is
4332 OK to do nothing, because cleanups aren't possible here. */
4334 ++block_stack->data.block.conditional_code;
4337 /* Mark the end of a conditional region of code. Because cleanup
4338 deferrals may be nested, we may still be in a conditional region
4339 after we end the currently deferred cleanups, only after we end all
4340 deferred cleanups, are we back in unconditional code. */
4343 end_cleanup_deferral ()
4345 /* block_stack can be NULL if we are inside the parameter list. It is
4346 OK to do nothing, because cleanups aren't possible here. */
4348 --block_stack->data.block.conditional_code;
4352 last_cleanup_this_contour ()
4354 if (block_stack == 0)
4357 return block_stack->data.block.cleanups;
4360 /* Return 1 if there are any pending cleanups at this point.
4361 If THIS_CONTOUR is nonzero, check the current contour as well.
4362 Otherwise, look only at the contours that enclose this one. */
4365 any_pending_cleanups (this_contour)
4368 struct nesting *block;
4370 if (cfun == NULL || cfun->stmt == NULL || block_stack == 0)
4373 if (this_contour && block_stack->data.block.cleanups != NULL)
4375 if (block_stack->data.block.cleanups == 0
4376 && block_stack->data.block.outer_cleanups == 0)
4379 for (block = block_stack->next; block; block = block->next)
4380 if (block->data.block.cleanups != 0)
4386 /* Enter a case (Pascal) or switch (C) statement.
4387 Push a block onto case_stack and nesting_stack
4388 to accumulate the case-labels that are seen
4389 and to record the labels generated for the statement.
4391 EXIT_FLAG is nonzero if `exit_something' should exit this case stmt.
4392 Otherwise, this construct is transparent for `exit_something'.
4394 EXPR is the index-expression to be dispatched on.
4395 TYPE is its nominal type. We could simply convert EXPR to this type,
4396 but instead we take short cuts. */
4399 expand_start_case (exit_flag, expr, type, printname)
4403 const char *printname;
4405 struct nesting *thiscase = ALLOC_NESTING ();
4407 /* Make an entry on case_stack for the case we are entering. */
4409 thiscase->desc = CASE_NESTING;
4410 thiscase->next = case_stack;
4411 thiscase->all = nesting_stack;
4412 thiscase->depth = ++nesting_depth;
4413 thiscase->exit_label = exit_flag ? gen_label_rtx () : 0;
4414 thiscase->data.case_stmt.case_list = 0;
4415 thiscase->data.case_stmt.index_expr = expr;
4416 thiscase->data.case_stmt.nominal_type = type;
4417 thiscase->data.case_stmt.default_label = 0;
4418 thiscase->data.case_stmt.printname = printname;
4419 thiscase->data.case_stmt.line_number_status = force_line_numbers ();
4420 case_stack = thiscase;
4421 nesting_stack = thiscase;
4423 do_pending_stack_adjust ();
4425 /* Make sure case_stmt.start points to something that won't
4426 need any transformation before expand_end_case. */
4427 if (GET_CODE (get_last_insn ()) != NOTE)
4428 emit_note (NULL, NOTE_INSN_DELETED);
4430 thiscase->data.case_stmt.start = get_last_insn ();
4432 start_cleanup_deferral ();
4435 /* Start a "dummy case statement" within which case labels are invalid
4436 and are not connected to any larger real case statement.
4437 This can be used if you don't want to let a case statement jump
4438 into the middle of certain kinds of constructs. */
4441 expand_start_case_dummy ()
4443 struct nesting *thiscase = ALLOC_NESTING ();
4445 /* Make an entry on case_stack for the dummy. */
4447 thiscase->desc = CASE_NESTING;
4448 thiscase->next = case_stack;
4449 thiscase->all = nesting_stack;
4450 thiscase->depth = ++nesting_depth;
4451 thiscase->exit_label = 0;
4452 thiscase->data.case_stmt.case_list = 0;
4453 thiscase->data.case_stmt.start = 0;
4454 thiscase->data.case_stmt.nominal_type = 0;
4455 thiscase->data.case_stmt.default_label = 0;
4456 case_stack = thiscase;
4457 nesting_stack = thiscase;
4458 start_cleanup_deferral ();
4464 /* If this is the first label, warn if any insns have been emitted. */
4465 if (case_stack->data.case_stmt.line_number_status >= 0)
4469 restore_line_number_status
4470 (case_stack->data.case_stmt.line_number_status);
4471 case_stack->data.case_stmt.line_number_status = -1;
4473 for (insn = case_stack->data.case_stmt.start;
4475 insn = NEXT_INSN (insn))
4477 if (GET_CODE (insn) == CODE_LABEL)
4479 if (GET_CODE (insn) != NOTE
4480 && (GET_CODE (insn) != INSN || GET_CODE (PATTERN (insn)) != USE))
4483 insn = PREV_INSN (insn);
4484 while (insn && (GET_CODE (insn) != NOTE || NOTE_LINE_NUMBER (insn) < 0));
4486 /* If insn is zero, then there must have been a syntax error. */
4488 warning_with_file_and_line (NOTE_SOURCE_FILE (insn),
4489 NOTE_LINE_NUMBER (insn),
4490 "unreachable code at beginning of %s",
4491 case_stack->data.case_stmt.printname);
4498 /* Accumulate one case or default label inside a case or switch statement.
4499 VALUE is the value of the case (a null pointer, for a default label).
4500 The function CONVERTER, when applied to arguments T and V,
4501 converts the value V to the type T.
4503 If not currently inside a case or switch statement, return 1 and do
4504 nothing. The caller will print a language-specific error message.
4505 If VALUE is a duplicate or overlaps, return 2 and do nothing
4506 except store the (first) duplicate node in *DUPLICATE.
4507 If VALUE is out of range, return 3 and do nothing.
4508 If we are jumping into the scope of a cleanup or var-sized array, return 5.
4509 Return 0 on success.
4511 Extended to handle range statements. */
4514 pushcase (value, converter, label, duplicate)
4516 tree (*converter) PARAMS ((tree, tree));
4523 /* Fail if not inside a real case statement. */
4524 if (! (case_stack && case_stack->data.case_stmt.start))
4527 if (stack_block_stack
4528 && stack_block_stack->depth > case_stack->depth)
4531 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
4532 nominal_type = case_stack->data.case_stmt.nominal_type;
4534 /* If the index is erroneous, avoid more problems: pretend to succeed. */
4535 if (index_type == error_mark_node)
4538 /* Convert VALUE to the type in which the comparisons are nominally done. */
4540 value = (*converter) (nominal_type, value);
4544 /* Fail if this value is out of range for the actual type of the index
4545 (which may be narrower than NOMINAL_TYPE). */
4547 && (TREE_CONSTANT_OVERFLOW (value)
4548 || ! int_fits_type_p (value, index_type)))
4551 return add_case_node (value, value, label, duplicate);
4554 /* Like pushcase but this case applies to all values between VALUE1 and
4555 VALUE2 (inclusive). If VALUE1 is NULL, the range starts at the lowest
4556 value of the index type and ends at VALUE2. If VALUE2 is NULL, the range
4557 starts at VALUE1 and ends at the highest value of the index type.
4558 If both are NULL, this case applies to all values.
4560 The return value is the same as that of pushcase but there is one
4561 additional error code: 4 means the specified range was empty. */
4564 pushcase_range (value1, value2, converter, label, duplicate)
4565 tree value1, value2;
4566 tree (*converter) PARAMS ((tree, tree));
4573 /* Fail if not inside a real case statement. */
4574 if (! (case_stack && case_stack->data.case_stmt.start))
4577 if (stack_block_stack
4578 && stack_block_stack->depth > case_stack->depth)
4581 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
4582 nominal_type = case_stack->data.case_stmt.nominal_type;
4584 /* If the index is erroneous, avoid more problems: pretend to succeed. */
4585 if (index_type == error_mark_node)
4590 /* Convert VALUEs to type in which the comparisons are nominally done
4591 and replace any unspecified value with the corresponding bound. */
4593 value1 = TYPE_MIN_VALUE (index_type);
4595 value2 = TYPE_MAX_VALUE (index_type);
4597 /* Fail if the range is empty. Do this before any conversion since
4598 we want to allow out-of-range empty ranges. */
4599 if (value2 != 0 && tree_int_cst_lt (value2, value1))
4602 /* If the max was unbounded, use the max of the nominal_type we are
4603 converting to. Do this after the < check above to suppress false
4606 value2 = TYPE_MAX_VALUE (nominal_type);
4608 value1 = (*converter) (nominal_type, value1);
4609 value2 = (*converter) (nominal_type, value2);
4611 /* Fail if these values are out of range. */
4612 if (TREE_CONSTANT_OVERFLOW (value1)
4613 || ! int_fits_type_p (value1, index_type))
4616 if (TREE_CONSTANT_OVERFLOW (value2)
4617 || ! int_fits_type_p (value2, index_type))
4620 return add_case_node (value1, value2, label, duplicate);
4623 /* Do the actual insertion of a case label for pushcase and pushcase_range
4624 into case_stack->data.case_stmt.case_list. Use an AVL tree to avoid
4625 slowdown for large switch statements. */
4628 add_case_node (low, high, label, duplicate)
4633 struct case_node *p, **q, *r;
4635 /* If there's no HIGH value, then this is not a case range; it's
4636 just a simple case label. But that's just a degenerate case
4641 /* Handle default labels specially. */
4644 if (case_stack->data.case_stmt.default_label != 0)
4646 *duplicate = case_stack->data.case_stmt.default_label;
4649 case_stack->data.case_stmt.default_label = label;
4650 expand_label (label);
4654 q = &case_stack->data.case_stmt.case_list;
4661 /* Keep going past elements distinctly greater than HIGH. */
4662 if (tree_int_cst_lt (high, p->low))
4665 /* or distinctly less than LOW. */
4666 else if (tree_int_cst_lt (p->high, low))
4671 /* We have an overlap; this is an error. */
4672 *duplicate = p->code_label;
4677 /* Add this label to the chain, and succeed. */
4679 r = (struct case_node *) ggc_alloc (sizeof (struct case_node));
4682 /* If the bounds are equal, turn this into the one-value case. */
4683 if (tree_int_cst_equal (low, high))
4688 r->code_label = label;
4689 expand_label (label);
4699 struct case_node *s;
4705 if (! (b = p->balance))
4706 /* Growth propagation from left side. */
4713 if ((p->left = s = r->right))
4722 if ((r->parent = s))
4730 case_stack->data.case_stmt.case_list = r;
4733 /* r->balance == +1 */
4738 struct case_node *t = r->right;
4740 if ((p->left = s = t->right))
4744 if ((r->right = s = t->left))
4758 if ((t->parent = s))
4766 case_stack->data.case_stmt.case_list = t;
4773 /* p->balance == +1; growth of left side balances the node. */
4783 if (! (b = p->balance))
4784 /* Growth propagation from right side. */
4792 if ((p->right = s = r->left))
4800 if ((r->parent = s))
4809 case_stack->data.case_stmt.case_list = r;
4813 /* r->balance == -1 */
4817 struct case_node *t = r->left;
4819 if ((p->right = s = t->left))
4824 if ((r->left = s = t->right))
4838 if ((t->parent = s))
4847 case_stack->data.case_stmt.case_list = t;
4853 /* p->balance == -1; growth of right side balances the node. */
4866 /* Returns the number of possible values of TYPE.
4867 Returns -1 if the number is unknown, variable, or if the number does not
4868 fit in a HOST_WIDE_INT.
4869 Sets *SPARSENESS to 2 if TYPE is an ENUMERAL_TYPE whose values
4870 do not increase monotonically (there may be duplicates);
4871 to 1 if the values increase monotonically, but not always by 1;
4872 otherwise sets it to 0. */
4875 all_cases_count (type, sparseness)
4880 HOST_WIDE_INT count, minval, lastval;
4884 switch (TREE_CODE (type))
4891 count = 1 << BITS_PER_UNIT;
4896 if (TYPE_MAX_VALUE (type) != 0
4897 && 0 != (t = fold (build (MINUS_EXPR, type, TYPE_MAX_VALUE (type),
4898 TYPE_MIN_VALUE (type))))
4899 && 0 != (t = fold (build (PLUS_EXPR, type, t,
4900 convert (type, integer_zero_node))))
4901 && host_integerp (t, 1))
4902 count = tree_low_cst (t, 1);
4908 /* Don't waste time with enumeral types with huge values. */
4909 if (! host_integerp (TYPE_MIN_VALUE (type), 0)
4910 || TYPE_MAX_VALUE (type) == 0
4911 || ! host_integerp (TYPE_MAX_VALUE (type), 0))
4914 lastval = minval = tree_low_cst (TYPE_MIN_VALUE (type), 0);
4917 for (t = TYPE_VALUES (type); t != NULL_TREE; t = TREE_CHAIN (t))
4919 HOST_WIDE_INT thisval = tree_low_cst (TREE_VALUE (t), 0);
4921 if (*sparseness == 2 || thisval <= lastval)
4923 else if (thisval != minval + count)
4934 #define BITARRAY_TEST(ARRAY, INDEX) \
4935 ((ARRAY)[(unsigned) (INDEX) / HOST_BITS_PER_CHAR]\
4936 & (1 << ((unsigned) (INDEX) % HOST_BITS_PER_CHAR)))
4937 #define BITARRAY_SET(ARRAY, INDEX) \
4938 ((ARRAY)[(unsigned) (INDEX) / HOST_BITS_PER_CHAR]\
4939 |= 1 << ((unsigned) (INDEX) % HOST_BITS_PER_CHAR))
4941 /* Set the elements of the bitstring CASES_SEEN (which has length COUNT),
4942 with the case values we have seen, assuming the case expression
4944 SPARSENESS is as determined by all_cases_count.
4946 The time needed is proportional to COUNT, unless
4947 SPARSENESS is 2, in which case quadratic time is needed. */
4950 mark_seen_cases (type, cases_seen, count, sparseness)
4952 unsigned char *cases_seen;
4953 HOST_WIDE_INT count;
4956 tree next_node_to_try = NULL_TREE;
4957 HOST_WIDE_INT next_node_offset = 0;
4959 struct case_node *n, *root = case_stack->data.case_stmt.case_list;
4960 tree val = make_node (INTEGER_CST);
4962 TREE_TYPE (val) = type;
4966 else if (sparseness == 2)
4969 unsigned HOST_WIDE_INT xlo;
4971 /* This less efficient loop is only needed to handle
4972 duplicate case values (multiple enum constants
4973 with the same value). */
4974 TREE_TYPE (val) = TREE_TYPE (root->low);
4975 for (t = TYPE_VALUES (type), xlo = 0; t != NULL_TREE;
4976 t = TREE_CHAIN (t), xlo++)
4978 TREE_INT_CST_LOW (val) = TREE_INT_CST_LOW (TREE_VALUE (t));
4979 TREE_INT_CST_HIGH (val) = TREE_INT_CST_HIGH (TREE_VALUE (t));
4983 /* Keep going past elements distinctly greater than VAL. */
4984 if (tree_int_cst_lt (val, n->low))
4987 /* or distinctly less than VAL. */
4988 else if (tree_int_cst_lt (n->high, val))
4993 /* We have found a matching range. */
4994 BITARRAY_SET (cases_seen, xlo);
5004 case_stack->data.case_stmt.case_list = root = case_tree2list (root, 0);
5006 for (n = root; n; n = n->right)
5008 TREE_INT_CST_LOW (val) = TREE_INT_CST_LOW (n->low);
5009 TREE_INT_CST_HIGH (val) = TREE_INT_CST_HIGH (n->low);
5010 while (! tree_int_cst_lt (n->high, val))
5012 /* Calculate (into xlo) the "offset" of the integer (val).
5013 The element with lowest value has offset 0, the next smallest
5014 element has offset 1, etc. */
5016 unsigned HOST_WIDE_INT xlo;
5020 if (sparseness && TYPE_VALUES (type) != NULL_TREE)
5022 /* The TYPE_VALUES will be in increasing order, so
5023 starting searching where we last ended. */
5024 t = next_node_to_try;
5025 xlo = next_node_offset;
5031 t = TYPE_VALUES (type);
5034 if (tree_int_cst_equal (val, TREE_VALUE (t)))
5036 next_node_to_try = TREE_CHAIN (t);
5037 next_node_offset = xlo + 1;
5042 if (t == next_node_to_try)
5051 t = TYPE_MIN_VALUE (type);
5053 neg_double (TREE_INT_CST_LOW (t), TREE_INT_CST_HIGH (t),
5057 add_double (xlo, xhi,
5058 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val),
5062 if (xhi == 0 && xlo < (unsigned HOST_WIDE_INT) count)
5063 BITARRAY_SET (cases_seen, xlo);
5065 add_double (TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val),
5067 &TREE_INT_CST_LOW (val), &TREE_INT_CST_HIGH (val));
5073 /* Given a switch statement with an expression that is an enumeration
5074 type, warn if any of the enumeration type's literals are not
5075 covered by the case expressions of the switch. Also, warn if there
5076 are any extra switch cases that are *not* elements of the
5081 At one stage this function would: ``If all enumeration literals
5082 were covered by the case expressions, turn one of the expressions
5083 into the default expression since it should not be possible to fall
5084 through such a switch.''
5086 That code has since been removed as: ``This optimization is
5087 disabled because it causes valid programs to fail. ANSI C does not
5088 guarantee that an expression with enum type will have a value that
5089 is the same as one of the enumeration literals.'' */
5092 check_for_full_enumeration_handling (type)
5095 struct case_node *n;
5098 /* True iff the selector type is a numbered set mode. */
5101 /* The number of possible selector values. */
5104 /* For each possible selector value. a one iff it has been matched
5105 by a case value alternative. */
5106 unsigned char *cases_seen;
5108 /* The allocated size of cases_seen, in chars. */
5109 HOST_WIDE_INT bytes_needed;
5111 size = all_cases_count (type, &sparseness);
5112 bytes_needed = (size + HOST_BITS_PER_CHAR) / HOST_BITS_PER_CHAR;
5114 if (size > 0 && size < 600000
5115 /* We deliberately use calloc here, not cmalloc, so that we can suppress
5116 this optimization if we don't have enough memory rather than
5117 aborting, as xmalloc would do. */
5119 (unsigned char *) really_call_calloc (bytes_needed, 1)) != NULL)
5122 tree v = TYPE_VALUES (type);
5124 /* The time complexity of this code is normally O(N), where
5125 N being the number of members in the enumerated type.
5126 However, if type is an ENUMERAL_TYPE whose values do not
5127 increase monotonically, O(N*log(N)) time may be needed. */
5129 mark_seen_cases (type, cases_seen, size, sparseness);
5131 for (i = 0; v != NULL_TREE && i < size; i++, v = TREE_CHAIN (v))
5132 if (BITARRAY_TEST (cases_seen, i) == 0)
5133 warning ("enumeration value `%s' not handled in switch",
5134 IDENTIFIER_POINTER (TREE_PURPOSE (v)));
5139 /* Now we go the other way around; we warn if there are case
5140 expressions that don't correspond to enumerators. This can
5141 occur since C and C++ don't enforce type-checking of
5142 assignments to enumeration variables. */
5144 if (case_stack->data.case_stmt.case_list
5145 && case_stack->data.case_stmt.case_list->left)
5146 case_stack->data.case_stmt.case_list
5147 = case_tree2list (case_stack->data.case_stmt.case_list, 0);
5148 for (n = case_stack->data.case_stmt.case_list; n; n = n->right)
5150 for (chain = TYPE_VALUES (type);
5151 chain && !tree_int_cst_equal (n->low, TREE_VALUE (chain));
5152 chain = TREE_CHAIN (chain))
5157 if (TYPE_NAME (type) == 0)
5158 warning ("case value `%ld' not in enumerated type",
5159 (long) TREE_INT_CST_LOW (n->low));
5161 warning ("case value `%ld' not in enumerated type `%s'",
5162 (long) TREE_INT_CST_LOW (n->low),
5163 IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
5166 : DECL_NAME (TYPE_NAME (type))));
5168 if (!tree_int_cst_equal (n->low, n->high))
5170 for (chain = TYPE_VALUES (type);
5171 chain && !tree_int_cst_equal (n->high, TREE_VALUE (chain));
5172 chain = TREE_CHAIN (chain))
5177 if (TYPE_NAME (type) == 0)
5178 warning ("case value `%ld' not in enumerated type",
5179 (long) TREE_INT_CST_LOW (n->high));
5181 warning ("case value `%ld' not in enumerated type `%s'",
5182 (long) TREE_INT_CST_LOW (n->high),
5183 IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
5186 : DECL_NAME (TYPE_NAME (type))));
5193 /* Maximum number of case bit tests. */
5194 #define MAX_CASE_BIT_TESTS 3
5196 /* By default, enable case bit tests on targets with ashlsi3. */
5197 #ifndef CASE_USE_BIT_TESTS
5198 #define CASE_USE_BIT_TESTS (ashl_optab->handlers[word_mode].insn_code \
5199 != CODE_FOR_nothing)
5203 /* A case_bit_test represents a set of case nodes that may be
5204 selected from using a bit-wise comparison. HI and LO hold
5205 the integer to be tested against, LABEL contains the label
5206 to jump to upon success and BITS counts the number of case
5207 nodes handled by this test, typically the number of bits
5210 struct case_bit_test
5218 /* Determine whether "1 << x" is relatively cheap in word_mode. */
5220 static bool lshift_cheap_p ()
5222 static bool init = false;
5223 static bool cheap = true;
5227 rtx reg = gen_rtx_REG (word_mode, 10000);
5228 int cost = rtx_cost (gen_rtx_ASHIFT (word_mode, const1_rtx, reg), SET);
5229 cheap = cost < COSTS_N_INSNS (3);
5236 /* Comparison function for qsort to order bit tests by decreasing
5237 number of case nodes, i.e. the node with the most cases gets
5240 static int case_bit_test_cmp (p1, p2)
5244 const struct case_bit_test *d1 = p1;
5245 const struct case_bit_test *d2 = p2;
5247 return d2->bits - d1->bits;
5250 /* Expand a switch statement by a short sequence of bit-wise
5251 comparisons. "switch(x)" is effectively converted into
5252 "if ((1 << (x-MINVAL)) & CST)" where CST and MINVAL are
5255 INDEX_EXPR is the value being switched on, which is of
5256 type INDEX_TYPE. MINVAL is the lowest case value of in
5257 the case nodes, of INDEX_TYPE type, and RANGE is highest
5258 value minus MINVAL, also of type INDEX_TYPE. NODES is
5259 the set of case nodes, and DEFAULT_LABEL is the label to
5260 branch to should none of the cases match.
5262 There *MUST* be MAX_CASE_BIT_TESTS or less unique case
5266 emit_case_bit_tests (index_type, index_expr, minval, range,
5267 nodes, default_label)
5268 tree index_type, index_expr, minval, range;
5269 case_node_ptr nodes;
5272 struct case_bit_test test[MAX_CASE_BIT_TESTS];
5273 enum machine_mode mode;
5274 rtx expr, index, label;
5275 unsigned int i,j,lo,hi;
5276 struct case_node *n;
5280 for (n = nodes; n; n = n->right)
5282 label = label_rtx (n->code_label);
5283 for (i = 0; i < count; i++)
5284 if (same_case_target_p (label, test[i].label))
5289 if (count >= MAX_CASE_BIT_TESTS)
5293 test[i].label = label;
5300 lo = tree_low_cst (fold (build (MINUS_EXPR, index_type,
5301 n->low, minval)), 1);
5302 hi = tree_low_cst (fold (build (MINUS_EXPR, index_type,
5303 n->high, minval)), 1);
5304 for (j = lo; j <= hi; j++)
5305 if (j >= HOST_BITS_PER_WIDE_INT)
5306 test[i].hi |= (HOST_WIDE_INT) 1 << (j - HOST_BITS_PER_INT);
5308 test[i].lo |= (HOST_WIDE_INT) 1 << j;
5311 qsort (test, count, sizeof(*test), case_bit_test_cmp);
5313 index_expr = fold (build (MINUS_EXPR, index_type,
5314 convert (index_type, index_expr),
5315 convert (index_type, minval)));
5316 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
5318 index = protect_from_queue (index, 0);
5319 do_pending_stack_adjust ();
5321 mode = TYPE_MODE (index_type);
5322 expr = expand_expr (range, NULL_RTX, VOIDmode, 0);
5323 emit_cmp_and_jump_insns (index, expr, GTU, NULL_RTX, mode, 1,
5326 index = convert_to_mode (word_mode, index, 0);
5327 index = expand_binop (word_mode, ashl_optab, const1_rtx,
5328 index, NULL_RTX, 1, OPTAB_WIDEN);
5330 for (i = 0; i < count; i++)
5332 expr = immed_double_const (test[i].lo, test[i].hi, word_mode);
5333 expr = expand_binop (word_mode, and_optab, index, expr,
5334 NULL_RTX, 1, OPTAB_WIDEN);
5335 emit_cmp_and_jump_insns (expr, const0_rtx, NE, NULL_RTX,
5336 word_mode, 1, test[i].label);
5339 emit_jump (default_label);
5342 /* Terminate a case (Pascal) or switch (C) statement
5343 in which ORIG_INDEX is the expression to be tested.
5344 If ORIG_TYPE is not NULL, it is the original ORIG_INDEX
5345 type as given in the source before any compiler conversions.
5346 Generate the code to test it and jump to the right place. */
5349 expand_end_case_type (orig_index, orig_type)
5350 tree orig_index, orig_type;
5352 tree minval = NULL_TREE, maxval = NULL_TREE, range = NULL_TREE;
5353 rtx default_label = 0;
5354 struct case_node *n, *m;
5355 unsigned int count, uniq;
5361 rtx before_case, end, lab;
5362 struct nesting *thiscase = case_stack;
5363 tree index_expr, index_type;
5364 bool exit_done = false;
5367 /* Don't crash due to previous errors. */
5368 if (thiscase == NULL)
5371 index_expr = thiscase->data.case_stmt.index_expr;
5372 index_type = TREE_TYPE (index_expr);
5373 unsignedp = TREE_UNSIGNED (index_type);
5374 if (orig_type == NULL)
5375 orig_type = TREE_TYPE (orig_index);
5377 do_pending_stack_adjust ();
5379 /* This might get a spurious warning in the presence of a syntax error;
5380 it could be fixed by moving the call to check_seenlabel after the
5381 check for error_mark_node, and copying the code of check_seenlabel that
5382 deals with case_stack->data.case_stmt.line_number_status /
5383 restore_line_number_status in front of the call to end_cleanup_deferral;
5384 However, this might miss some useful warnings in the presence of
5385 non-syntax errors. */
5388 /* An ERROR_MARK occurs for various reasons including invalid data type. */
5389 if (index_type != error_mark_node)
5391 /* If the switch expression was an enumerated type, check that
5392 exactly all enumeration literals are covered by the cases.
5393 The check is made when -Wswitch was specified and there is no
5394 default case, or when -Wswitch-enum was specified. */
5395 if (((warn_switch && !thiscase->data.case_stmt.default_label)
5396 || warn_switch_enum)
5397 && TREE_CODE (orig_type) == ENUMERAL_TYPE
5398 && TREE_CODE (index_expr) != INTEGER_CST)
5399 check_for_full_enumeration_handling (orig_type);
5401 if (warn_switch_default && !thiscase->data.case_stmt.default_label)
5402 warning ("switch missing default case");
5404 /* If we don't have a default-label, create one here,
5405 after the body of the switch. */
5406 if (thiscase->data.case_stmt.default_label == 0)
5408 thiscase->data.case_stmt.default_label
5409 = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
5410 /* Share the exit label if possible. */
5411 if (thiscase->exit_label)
5413 SET_DECL_RTL (thiscase->data.case_stmt.default_label,
5414 thiscase->exit_label);
5417 expand_label (thiscase->data.case_stmt.default_label);
5419 default_label = label_rtx (thiscase->data.case_stmt.default_label);
5421 before_case = get_last_insn ();
5423 if (thiscase->data.case_stmt.case_list
5424 && thiscase->data.case_stmt.case_list->left)
5425 thiscase->data.case_stmt.case_list
5426 = case_tree2list (thiscase->data.case_stmt.case_list, 0);
5428 /* Simplify the case-list before we count it. */
5429 group_case_nodes (thiscase->data.case_stmt.case_list);
5430 strip_default_case_nodes (&thiscase->data.case_stmt.case_list,
5433 /* Get upper and lower bounds of case values.
5434 Also convert all the case values to the index expr's data type. */
5438 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5440 /* Check low and high label values are integers. */
5441 if (TREE_CODE (n->low) != INTEGER_CST)
5443 if (TREE_CODE (n->high) != INTEGER_CST)
5446 n->low = convert (index_type, n->low);
5447 n->high = convert (index_type, n->high);
5449 /* Count the elements and track the largest and smallest
5450 of them (treating them as signed even if they are not). */
5458 if (INT_CST_LT (n->low, minval))
5460 if (INT_CST_LT (maxval, n->high))
5463 /* A range counts double, since it requires two compares. */
5464 if (! tree_int_cst_equal (n->low, n->high))
5467 /* Count the number of unique case node targets. */
5469 lab = label_rtx (n->code_label);
5470 for (m = thiscase->data.case_stmt.case_list; m != n; m = m->right)
5471 if (same_case_target_p (label_rtx (m->code_label), lab))
5478 /* Compute span of values. */
5480 range = fold (build (MINUS_EXPR, index_type, maxval, minval));
5482 end_cleanup_deferral ();
5486 expand_expr (index_expr, const0_rtx, VOIDmode, 0);
5488 emit_jump (default_label);
5491 /* Try implementing this switch statement by a short sequence of
5492 bit-wise comparisons. However, we let the binary-tree case
5493 below handle constant index expressions. */
5494 else if (CASE_USE_BIT_TESTS
5495 && ! TREE_CONSTANT (index_expr)
5496 && compare_tree_int (range, GET_MODE_BITSIZE (word_mode)) < 0
5497 && lshift_cheap_p ()
5498 && ((uniq == 1 && count >= 3)
5499 || (uniq == 2 && count >= 5)
5500 || (uniq == 3 && count >= 6)))
5502 /* Optimize the case where all the case values fit in a
5503 word without having to subtract MINVAL. In this case,
5504 we can optimize away the subtraction. */
5505 if (compare_tree_int (minval, 0) > 0
5506 && compare_tree_int (maxval, GET_MODE_BITSIZE (word_mode)) < 0)
5508 minval = integer_zero_node;
5511 emit_case_bit_tests (index_type, index_expr, minval, range,
5512 thiscase->data.case_stmt.case_list,
5516 /* If range of values is much bigger than number of values,
5517 make a sequence of conditional branches instead of a dispatch.
5518 If the switch-index is a constant, do it this way
5519 because we can optimize it. */
5521 else if (count < case_values_threshold ()
5522 || compare_tree_int (range, 10 * count) > 0
5523 /* RANGE may be signed, and really large ranges will show up
5524 as negative numbers. */
5525 || compare_tree_int (range, 0) < 0
5526 #ifndef ASM_OUTPUT_ADDR_DIFF_ELT
5529 || TREE_CONSTANT (index_expr))
5531 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
5533 /* If the index is a short or char that we do not have
5534 an insn to handle comparisons directly, convert it to
5535 a full integer now, rather than letting each comparison
5536 generate the conversion. */
5538 if (GET_MODE_CLASS (GET_MODE (index)) == MODE_INT
5539 && ! have_insn_for (COMPARE, GET_MODE (index)))
5541 enum machine_mode wider_mode;
5542 for (wider_mode = GET_MODE (index); wider_mode != VOIDmode;
5543 wider_mode = GET_MODE_WIDER_MODE (wider_mode))
5544 if (have_insn_for (COMPARE, wider_mode))
5546 index = convert_to_mode (wider_mode, index, unsignedp);
5552 do_pending_stack_adjust ();
5554 index = protect_from_queue (index, 0);
5555 if (GET_CODE (index) == MEM)
5556 index = copy_to_reg (index);
5557 if (GET_CODE (index) == CONST_INT
5558 || TREE_CODE (index_expr) == INTEGER_CST)
5560 /* Make a tree node with the proper constant value
5561 if we don't already have one. */
5562 if (TREE_CODE (index_expr) != INTEGER_CST)
5565 = build_int_2 (INTVAL (index),
5566 unsignedp || INTVAL (index) >= 0 ? 0 : -1);
5567 index_expr = convert (index_type, index_expr);
5570 /* For constant index expressions we need only
5571 issue an unconditional branch to the appropriate
5572 target code. The job of removing any unreachable
5573 code is left to the optimisation phase if the
5574 "-O" option is specified. */
5575 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5576 if (! tree_int_cst_lt (index_expr, n->low)
5577 && ! tree_int_cst_lt (n->high, index_expr))
5581 emit_jump (label_rtx (n->code_label));
5583 emit_jump (default_label);
5587 /* If the index expression is not constant we generate
5588 a binary decision tree to select the appropriate
5589 target code. This is done as follows:
5591 The list of cases is rearranged into a binary tree,
5592 nearly optimal assuming equal probability for each case.
5594 The tree is transformed into RTL, eliminating
5595 redundant test conditions at the same time.
5597 If program flow could reach the end of the
5598 decision tree an unconditional jump to the
5599 default code is emitted. */
5602 = (TREE_CODE (orig_type) != ENUMERAL_TYPE
5603 && estimate_case_costs (thiscase->data.case_stmt.case_list));
5604 balance_case_nodes (&thiscase->data.case_stmt.case_list, NULL);
5605 emit_case_nodes (index, thiscase->data.case_stmt.case_list,
5606 default_label, index_type);
5607 emit_jump_if_reachable (default_label);
5612 table_label = gen_label_rtx ();
5613 if (! try_casesi (index_type, index_expr, minval, range,
5614 table_label, default_label))
5616 index_type = thiscase->data.case_stmt.nominal_type;
5618 /* Index jumptables from zero for suitable values of
5619 minval to avoid a subtraction. */
5621 && compare_tree_int (minval, 0) > 0
5622 && compare_tree_int (minval, 3) < 0)
5624 minval = integer_zero_node;
5628 if (! try_tablejump (index_type, index_expr, minval, range,
5629 table_label, default_label))
5633 /* Get table of labels to jump to, in order of case index. */
5635 ncases = tree_low_cst (range, 0) + 1;
5636 labelvec = (rtx *) alloca (ncases * sizeof (rtx));
5637 memset ((char *) labelvec, 0, ncases * sizeof (rtx));
5639 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5641 /* Compute the low and high bounds relative to the minimum
5642 value since that should fit in a HOST_WIDE_INT while the
5643 actual values may not. */
5645 = tree_low_cst (fold (build (MINUS_EXPR, index_type,
5646 n->low, minval)), 1);
5647 HOST_WIDE_INT i_high
5648 = tree_low_cst (fold (build (MINUS_EXPR, index_type,
5649 n->high, minval)), 1);
5652 for (i = i_low; i <= i_high; i ++)
5654 = gen_rtx_LABEL_REF (Pmode, label_rtx (n->code_label));
5657 /* Fill in the gaps with the default. */
5658 for (i = 0; i < ncases; i++)
5659 if (labelvec[i] == 0)
5660 labelvec[i] = gen_rtx_LABEL_REF (Pmode, default_label);
5662 /* Output the table */
5663 emit_label (table_label);
5665 if (CASE_VECTOR_PC_RELATIVE || flag_pic)
5666 emit_jump_insn (gen_rtx_ADDR_DIFF_VEC (CASE_VECTOR_MODE,
5667 gen_rtx_LABEL_REF (Pmode, table_label),
5668 gen_rtvec_v (ncases, labelvec),
5669 const0_rtx, const0_rtx));
5671 emit_jump_insn (gen_rtx_ADDR_VEC (CASE_VECTOR_MODE,
5672 gen_rtvec_v (ncases, labelvec)));
5674 /* If the case insn drops through the table,
5675 after the table we must jump to the default-label.
5676 Otherwise record no drop-through after the table. */
5677 #ifdef CASE_DROPS_THROUGH
5678 emit_jump (default_label);
5684 before_case = NEXT_INSN (before_case);
5685 end = get_last_insn ();
5686 if (squeeze_notes (&before_case, &end))
5688 reorder_insns (before_case, end,
5689 thiscase->data.case_stmt.start);
5692 end_cleanup_deferral ();
5694 if (thiscase->exit_label && !exit_done)
5695 emit_label (thiscase->exit_label);
5697 POPSTACK (case_stack);
5702 /* Convert the tree NODE into a list linked by the right field, with the left
5703 field zeroed. RIGHT is used for recursion; it is a list to be placed
5704 rightmost in the resulting list. */
5706 static struct case_node *
5707 case_tree2list (node, right)
5708 struct case_node *node, *right;
5710 struct case_node *left;
5713 right = case_tree2list (node->right, right);
5715 node->right = right;
5716 if ((left = node->left))
5719 return case_tree2list (left, node);
5725 /* Generate code to jump to LABEL if OP1 and OP2 are equal. */
5728 do_jump_if_equal (op1, op2, label, unsignedp)
5729 rtx op1, op2, label;
5732 if (GET_CODE (op1) == CONST_INT && GET_CODE (op2) == CONST_INT)
5734 if (INTVAL (op1) == INTVAL (op2))
5738 emit_cmp_and_jump_insns (op1, op2, EQ, NULL_RTX,
5739 (GET_MODE (op1) == VOIDmode
5740 ? GET_MODE (op2) : GET_MODE (op1)),
5744 /* Not all case values are encountered equally. This function
5745 uses a heuristic to weight case labels, in cases where that
5746 looks like a reasonable thing to do.
5748 Right now, all we try to guess is text, and we establish the
5751 chars above space: 16
5760 If we find any cases in the switch that are not either -1 or in the range
5761 of valid ASCII characters, or are control characters other than those
5762 commonly used with "\", don't treat this switch scanning text.
5764 Return 1 if these nodes are suitable for cost estimation, otherwise
5768 estimate_case_costs (node)
5771 tree min_ascii = integer_minus_one_node;
5772 tree max_ascii = convert (TREE_TYPE (node->high), build_int_2 (127, 0));
5776 /* If we haven't already made the cost table, make it now. Note that the
5777 lower bound of the table is -1, not zero. */
5779 if (! cost_table_initialized)
5781 cost_table_initialized = 1;
5783 for (i = 0; i < 128; i++)
5786 COST_TABLE (i) = 16;
5787 else if (ISPUNCT (i))
5789 else if (ISCNTRL (i))
5790 COST_TABLE (i) = -1;
5793 COST_TABLE (' ') = 8;
5794 COST_TABLE ('\t') = 4;
5795 COST_TABLE ('\0') = 4;
5796 COST_TABLE ('\n') = 2;
5797 COST_TABLE ('\f') = 1;
5798 COST_TABLE ('\v') = 1;
5799 COST_TABLE ('\b') = 1;
5802 /* See if all the case expressions look like text. It is text if the
5803 constant is >= -1 and the highest constant is <= 127. Do all comparisons
5804 as signed arithmetic since we don't want to ever access cost_table with a
5805 value less than -1. Also check that none of the constants in a range
5806 are strange control characters. */
5808 for (n = node; n; n = n->right)
5810 if ((INT_CST_LT (n->low, min_ascii)) || INT_CST_LT (max_ascii, n->high))
5813 for (i = (HOST_WIDE_INT) TREE_INT_CST_LOW (n->low);
5814 i <= (HOST_WIDE_INT) TREE_INT_CST_LOW (n->high); i++)
5815 if (COST_TABLE (i) < 0)
5819 /* All interesting values are within the range of interesting
5820 ASCII characters. */
5824 /* Determine whether two case labels branch to the same target. */
5827 same_case_target_p (l1, l2)
5835 i1 = next_real_insn (l1);
5836 i2 = next_real_insn (l2);
5840 if (i1 && simplejump_p (i1))
5842 l1 = XEXP (SET_SRC (PATTERN (i1)), 0);
5845 if (i2 && simplejump_p (i2))
5847 l2 = XEXP (SET_SRC (PATTERN (i2)), 0);
5852 /* Delete nodes that branch to the default label from a list of
5853 case nodes. Eg. case 5: default: becomes just default: */
5856 strip_default_case_nodes (prev, deflab)
5857 case_node_ptr *prev;
5865 if (same_case_target_p (label_rtx (ptr->code_label), deflab))
5872 /* Scan an ordered list of case nodes
5873 combining those with consecutive values or ranges.
5875 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
5878 group_case_nodes (head)
5881 case_node_ptr node = head;
5885 rtx lab = label_rtx (node->code_label);
5886 case_node_ptr np = node;
5888 /* Try to group the successors of NODE with NODE. */
5889 while (((np = np->right) != 0)
5890 /* Do they jump to the same place? */
5891 && same_case_target_p (label_rtx (np->code_label), lab)
5892 /* Are their ranges consecutive? */
5893 && tree_int_cst_equal (np->low,
5894 fold (build (PLUS_EXPR,
5895 TREE_TYPE (node->high),
5898 /* An overflow is not consecutive. */
5899 && tree_int_cst_lt (node->high,
5900 fold (build (PLUS_EXPR,
5901 TREE_TYPE (node->high),
5903 integer_one_node))))
5905 node->high = np->high;
5907 /* NP is the first node after NODE which can't be grouped with it.
5908 Delete the nodes in between, and move on to that node. */
5914 /* Take an ordered list of case nodes
5915 and transform them into a near optimal binary tree,
5916 on the assumption that any target code selection value is as
5917 likely as any other.
5919 The transformation is performed by splitting the ordered
5920 list into two equal sections plus a pivot. The parts are
5921 then attached to the pivot as left and right branches. Each
5922 branch is then transformed recursively. */
5925 balance_case_nodes (head, parent)
5926 case_node_ptr *head;
5927 case_node_ptr parent;
5940 /* Count the number of entries on branch. Also count the ranges. */
5944 if (!tree_int_cst_equal (np->low, np->high))
5948 cost += COST_TABLE (TREE_INT_CST_LOW (np->high));
5952 cost += COST_TABLE (TREE_INT_CST_LOW (np->low));
5960 /* Split this list if it is long enough for that to help. */
5965 /* Find the place in the list that bisects the list's total cost,
5966 Here I gets half the total cost. */
5971 /* Skip nodes while their cost does not reach that amount. */
5972 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
5973 i -= COST_TABLE (TREE_INT_CST_LOW ((*npp)->high));
5974 i -= COST_TABLE (TREE_INT_CST_LOW ((*npp)->low));
5977 npp = &(*npp)->right;
5982 /* Leave this branch lopsided, but optimize left-hand
5983 side and fill in `parent' fields for right-hand side. */
5985 np->parent = parent;
5986 balance_case_nodes (&np->left, np);
5987 for (; np->right; np = np->right)
5988 np->right->parent = np;
5992 /* If there are just three nodes, split at the middle one. */
5994 npp = &(*npp)->right;
5997 /* Find the place in the list that bisects the list's total cost,
5998 where ranges count as 2.
5999 Here I gets half the total cost. */
6000 i = (i + ranges + 1) / 2;
6003 /* Skip nodes while their cost does not reach that amount. */
6004 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
6009 npp = &(*npp)->right;
6014 np->parent = parent;
6017 /* Optimize each of the two split parts. */
6018 balance_case_nodes (&np->left, np);
6019 balance_case_nodes (&np->right, np);
6023 /* Else leave this branch as one level,
6024 but fill in `parent' fields. */
6026 np->parent = parent;
6027 for (; np->right; np = np->right)
6028 np->right->parent = np;
6033 /* Search the parent sections of the case node tree
6034 to see if a test for the lower bound of NODE would be redundant.
6035 INDEX_TYPE is the type of the index expression.
6037 The instructions to generate the case decision tree are
6038 output in the same order as nodes are processed so it is
6039 known that if a parent node checks the range of the current
6040 node minus one that the current node is bounded at its lower
6041 span. Thus the test would be redundant. */
6044 node_has_low_bound (node, index_type)
6049 case_node_ptr pnode;
6051 /* If the lower bound of this node is the lowest value in the index type,
6052 we need not test it. */
6054 if (tree_int_cst_equal (node->low, TYPE_MIN_VALUE (index_type)))
6057 /* If this node has a left branch, the value at the left must be less
6058 than that at this node, so it cannot be bounded at the bottom and
6059 we need not bother testing any further. */
6064 low_minus_one = fold (build (MINUS_EXPR, TREE_TYPE (node->low),
6065 node->low, integer_one_node));
6067 /* If the subtraction above overflowed, we can't verify anything.
6068 Otherwise, look for a parent that tests our value - 1. */
6070 if (! tree_int_cst_lt (low_minus_one, node->low))
6073 for (pnode = node->parent; pnode; pnode = pnode->parent)
6074 if (tree_int_cst_equal (low_minus_one, pnode->high))
6080 /* Search the parent sections of the case node tree
6081 to see if a test for the upper bound of NODE would be redundant.
6082 INDEX_TYPE is the type of the index expression.
6084 The instructions to generate the case decision tree are
6085 output in the same order as nodes are processed so it is
6086 known that if a parent node checks the range of the current
6087 node plus one that the current node is bounded at its upper
6088 span. Thus the test would be redundant. */
6091 node_has_high_bound (node, index_type)
6096 case_node_ptr pnode;
6098 /* If there is no upper bound, obviously no test is needed. */
6100 if (TYPE_MAX_VALUE (index_type) == NULL)
6103 /* If the upper bound of this node is the highest value in the type
6104 of the index expression, we need not test against it. */
6106 if (tree_int_cst_equal (node->high, TYPE_MAX_VALUE (index_type)))
6109 /* If this node has a right branch, the value at the right must be greater
6110 than that at this node, so it cannot be bounded at the top and
6111 we need not bother testing any further. */
6116 high_plus_one = fold (build (PLUS_EXPR, TREE_TYPE (node->high),
6117 node->high, integer_one_node));
6119 /* If the addition above overflowed, we can't verify anything.
6120 Otherwise, look for a parent that tests our value + 1. */
6122 if (! tree_int_cst_lt (node->high, high_plus_one))
6125 for (pnode = node->parent; pnode; pnode = pnode->parent)
6126 if (tree_int_cst_equal (high_plus_one, pnode->low))
6132 /* Search the parent sections of the
6133 case node tree to see if both tests for the upper and lower
6134 bounds of NODE would be redundant. */
6137 node_is_bounded (node, index_type)
6141 return (node_has_low_bound (node, index_type)
6142 && node_has_high_bound (node, index_type));
6145 /* Emit an unconditional jump to LABEL unless it would be dead code. */
6148 emit_jump_if_reachable (label)
6151 if (GET_CODE (get_last_insn ()) != BARRIER)
6155 /* Emit step-by-step code to select a case for the value of INDEX.
6156 The thus generated decision tree follows the form of the
6157 case-node binary tree NODE, whose nodes represent test conditions.
6158 INDEX_TYPE is the type of the index of the switch.
6160 Care is taken to prune redundant tests from the decision tree
6161 by detecting any boundary conditions already checked by
6162 emitted rtx. (See node_has_high_bound, node_has_low_bound
6163 and node_is_bounded, above.)
6165 Where the test conditions can be shown to be redundant we emit
6166 an unconditional jump to the target code. As a further
6167 optimization, the subordinates of a tree node are examined to
6168 check for bounded nodes. In this case conditional and/or
6169 unconditional jumps as a result of the boundary check for the
6170 current node are arranged to target the subordinates associated
6171 code for out of bound conditions on the current node.
6173 We can assume that when control reaches the code generated here,
6174 the index value has already been compared with the parents
6175 of this node, and determined to be on the same side of each parent
6176 as this node is. Thus, if this node tests for the value 51,
6177 and a parent tested for 52, we don't need to consider
6178 the possibility of a value greater than 51. If another parent
6179 tests for the value 50, then this node need not test anything. */
6182 emit_case_nodes (index, node, default_label, index_type)
6188 /* If INDEX has an unsigned type, we must make unsigned branches. */
6189 int unsignedp = TREE_UNSIGNED (index_type);
6190 enum machine_mode mode = GET_MODE (index);
6191 enum machine_mode imode = TYPE_MODE (index_type);
6193 /* See if our parents have already tested everything for us.
6194 If they have, emit an unconditional jump for this node. */
6195 if (node_is_bounded (node, index_type))
6196 emit_jump (label_rtx (node->code_label));
6198 else if (tree_int_cst_equal (node->low, node->high))
6200 /* Node is single valued. First see if the index expression matches
6201 this node and then check our children, if any. */
6203 do_jump_if_equal (index,
6204 convert_modes (mode, imode,
6205 expand_expr (node->low, NULL_RTX,
6208 label_rtx (node->code_label), unsignedp);
6210 if (node->right != 0 && node->left != 0)
6212 /* This node has children on both sides.
6213 Dispatch to one side or the other
6214 by comparing the index value with this node's value.
6215 If one subtree is bounded, check that one first,
6216 so we can avoid real branches in the tree. */
6218 if (node_is_bounded (node->right, index_type))
6220 emit_cmp_and_jump_insns (index,
6223 expand_expr (node->high, NULL_RTX,
6226 GT, NULL_RTX, mode, unsignedp,
6227 label_rtx (node->right->code_label));
6228 emit_case_nodes (index, node->left, default_label, index_type);
6231 else if (node_is_bounded (node->left, index_type))
6233 emit_cmp_and_jump_insns (index,
6236 expand_expr (node->high, NULL_RTX,
6239 LT, NULL_RTX, mode, unsignedp,
6240 label_rtx (node->left->code_label));
6241 emit_case_nodes (index, node->right, default_label, index_type);
6246 /* Neither node is bounded. First distinguish the two sides;
6247 then emit the code for one side at a time. */
6249 tree test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
6251 /* See if the value is on the right. */
6252 emit_cmp_and_jump_insns (index,
6255 expand_expr (node->high, NULL_RTX,
6258 GT, NULL_RTX, mode, unsignedp,
6259 label_rtx (test_label));
6261 /* Value must be on the left.
6262 Handle the left-hand subtree. */
6263 emit_case_nodes (index, node->left, default_label, index_type);
6264 /* If left-hand subtree does nothing,
6266 emit_jump_if_reachable (default_label);
6268 /* Code branches here for the right-hand subtree. */
6269 expand_label (test_label);
6270 emit_case_nodes (index, node->right, default_label, index_type);
6274 else if (node->right != 0 && node->left == 0)
6276 /* Here we have a right child but no left so we issue conditional
6277 branch to default and process the right child.
6279 Omit the conditional branch to default if we it avoid only one
6280 right child; it costs too much space to save so little time. */
6282 if (node->right->right || node->right->left
6283 || !tree_int_cst_equal (node->right->low, node->right->high))
6285 if (!node_has_low_bound (node, index_type))
6287 emit_cmp_and_jump_insns (index,
6290 expand_expr (node->high, NULL_RTX,
6293 LT, NULL_RTX, mode, unsignedp,
6297 emit_case_nodes (index, node->right, default_label, index_type);
6300 /* We cannot process node->right normally
6301 since we haven't ruled out the numbers less than
6302 this node's value. So handle node->right explicitly. */
6303 do_jump_if_equal (index,
6306 expand_expr (node->right->low, NULL_RTX,
6309 label_rtx (node->right->code_label), unsignedp);
6312 else if (node->right == 0 && node->left != 0)
6314 /* Just one subtree, on the left. */
6315 if (node->left->left || node->left->right
6316 || !tree_int_cst_equal (node->left->low, node->left->high))
6318 if (!node_has_high_bound (node, index_type))
6320 emit_cmp_and_jump_insns (index,
6323 expand_expr (node->high, NULL_RTX,
6326 GT, NULL_RTX, mode, unsignedp,
6330 emit_case_nodes (index, node->left, default_label, index_type);
6333 /* We cannot process node->left normally
6334 since we haven't ruled out the numbers less than
6335 this node's value. So handle node->left explicitly. */
6336 do_jump_if_equal (index,
6339 expand_expr (node->left->low, NULL_RTX,
6342 label_rtx (node->left->code_label), unsignedp);
6347 /* Node is a range. These cases are very similar to those for a single
6348 value, except that we do not start by testing whether this node
6349 is the one to branch to. */
6351 if (node->right != 0 && node->left != 0)
6353 /* Node has subtrees on both sides.
6354 If the right-hand subtree is bounded,
6355 test for it first, since we can go straight there.
6356 Otherwise, we need to make a branch in the control structure,
6357 then handle the two subtrees. */
6358 tree test_label = 0;
6360 if (node_is_bounded (node->right, index_type))
6361 /* Right hand node is fully bounded so we can eliminate any
6362 testing and branch directly to the target code. */
6363 emit_cmp_and_jump_insns (index,
6366 expand_expr (node->high, NULL_RTX,
6369 GT, NULL_RTX, mode, unsignedp,
6370 label_rtx (node->right->code_label));
6373 /* Right hand node requires testing.
6374 Branch to a label where we will handle it later. */
6376 test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
6377 emit_cmp_and_jump_insns (index,
6380 expand_expr (node->high, NULL_RTX,
6383 GT, NULL_RTX, mode, unsignedp,
6384 label_rtx (test_label));
6387 /* Value belongs to this node or to the left-hand subtree. */
6389 emit_cmp_and_jump_insns (index,
6392 expand_expr (node->low, NULL_RTX,
6395 GE, NULL_RTX, mode, unsignedp,
6396 label_rtx (node->code_label));
6398 /* Handle the left-hand subtree. */
6399 emit_case_nodes (index, node->left, default_label, index_type);
6401 /* If right node had to be handled later, do that now. */
6405 /* If the left-hand subtree fell through,
6406 don't let it fall into the right-hand subtree. */
6407 emit_jump_if_reachable (default_label);
6409 expand_label (test_label);
6410 emit_case_nodes (index, node->right, default_label, index_type);
6414 else if (node->right != 0 && node->left == 0)
6416 /* Deal with values to the left of this node,
6417 if they are possible. */
6418 if (!node_has_low_bound (node, index_type))
6420 emit_cmp_and_jump_insns (index,
6423 expand_expr (node->low, NULL_RTX,
6426 LT, NULL_RTX, mode, unsignedp,
6430 /* Value belongs to this node or to the right-hand subtree. */
6432 emit_cmp_and_jump_insns (index,
6435 expand_expr (node->high, NULL_RTX,
6438 LE, NULL_RTX, mode, unsignedp,
6439 label_rtx (node->code_label));
6441 emit_case_nodes (index, node->right, default_label, index_type);
6444 else if (node->right == 0 && node->left != 0)
6446 /* Deal with values to the right of this node,
6447 if they are possible. */
6448 if (!node_has_high_bound (node, index_type))
6450 emit_cmp_and_jump_insns (index,
6453 expand_expr (node->high, NULL_RTX,
6456 GT, NULL_RTX, mode, unsignedp,
6460 /* Value belongs to this node or to the left-hand subtree. */
6462 emit_cmp_and_jump_insns (index,
6465 expand_expr (node->low, NULL_RTX,
6468 GE, NULL_RTX, mode, unsignedp,
6469 label_rtx (node->code_label));
6471 emit_case_nodes (index, node->left, default_label, index_type);
6476 /* Node has no children so we check low and high bounds to remove
6477 redundant tests. Only one of the bounds can exist,
6478 since otherwise this node is bounded--a case tested already. */
6479 int high_bound = node_has_high_bound (node, index_type);
6480 int low_bound = node_has_low_bound (node, index_type);
6482 if (!high_bound && low_bound)
6484 emit_cmp_and_jump_insns (index,
6487 expand_expr (node->high, NULL_RTX,
6490 GT, NULL_RTX, mode, unsignedp,
6494 else if (!low_bound && high_bound)
6496 emit_cmp_and_jump_insns (index,
6499 expand_expr (node->low, NULL_RTX,
6502 LT, NULL_RTX, mode, unsignedp,
6505 else if (!low_bound && !high_bound)
6507 /* Widen LOW and HIGH to the same width as INDEX. */
6508 tree type = (*lang_hooks.types.type_for_mode) (mode, unsignedp);
6509 tree low = build1 (CONVERT_EXPR, type, node->low);
6510 tree high = build1 (CONVERT_EXPR, type, node->high);
6511 rtx low_rtx, new_index, new_bound;
6513 /* Instead of doing two branches, emit one unsigned branch for
6514 (index-low) > (high-low). */
6515 low_rtx = expand_expr (low, NULL_RTX, mode, 0);
6516 new_index = expand_simple_binop (mode, MINUS, index, low_rtx,
6517 NULL_RTX, unsignedp,
6519 new_bound = expand_expr (fold (build (MINUS_EXPR, type,
6523 emit_cmp_and_jump_insns (new_index, new_bound, GT, NULL_RTX,
6524 mode, 1, default_label);
6527 emit_jump (label_rtx (node->code_label));
6532 #include "gt-stmt.h"