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[official-gcc.git] / gcc / stmt.c
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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
10 version.
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
15 for more details.
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
20 02111-1307, USA. */
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. */
36 #include "config.h"
37 #include "system.h"
38 #include "coretypes.h"
39 #include "tm.h"
41 #include "rtl.h"
42 #include "tree.h"
43 #include "tm_p.h"
44 #include "flags.h"
45 #include "except.h"
46 #include "function.h"
47 #include "insn-config.h"
48 #include "expr.h"
49 #include "libfuncs.h"
50 #include "hard-reg-set.h"
51 #include "loop.h"
52 #include "recog.h"
53 #include "machmode.h"
54 #include "toplev.h"
55 #include "output.h"
56 #include "ggc.h"
57 #include "langhooks.h"
58 #include "predict.h"
59 #include "optabs.h"
61 /* Assume that case vectors are not pc-relative. */
62 #ifndef CASE_VECTOR_PC_RELATIVE
63 #define CASE_VECTOR_PC_RELATIVE 0
64 #endif
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
80 node chain.
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
88 in order. */
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 */
98 int balance;
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
112 is unsigned. */
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(())
142 struct nesting *all;
143 struct nesting *next;
144 int depth;
145 rtx exit_label;
146 enum nesting_desc {
147 COND_NESTING,
148 LOOP_NESTING,
149 BLOCK_NESTING,
150 CASE_NESTING
151 } desc;
152 union nesting_u
154 /* For conds (if-then and if-then-else statements). */
155 struct nesting_cond
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. */
160 rtx endif_label;
161 /* Label for the end of this alternative.
162 This may be the end of the if or the next else/elseif. */
163 rtx next_label;
164 } GTY ((tag ("COND_NESTING"))) cond;
165 /* For loops. */
166 struct nesting_loop
168 /* Label at the top of the loop; place to loop back to. */
169 rtx start_label;
170 /* Label at the end of the whole construct. */
171 rtx end_label;
172 /* Label for `continue' statement to jump to;
173 this is in front of the stepper of the loop. */
174 rtx continue_label;
175 } GTY ((tag ("LOOP_NESTING"))) loop;
176 /* For variable binding contours. */
177 struct nesting_block
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. */
183 rtx stack_level;
184 /* The NOTE that starts this contour.
185 Used by expand_goto to check whether the destination
186 is within each contour or not. */
187 rtx first_insn;
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. */
194 tree cleanups;
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. */
203 tree outer_cleanups;
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
215 end of the block. */
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'). */
230 struct nesting_case
232 /* The insn after which the case dispatch should finally
233 be emitted. Zero for a dummy. */
234 rtx start;
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. */
240 tree default_label;
241 /* The expression to be dispatched on. */
242 tree index_expr;
243 /* Type that INDEX_EXPR should be converted to. */
244 tree nominal_type;
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
249 case statement. */
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,
288 we check each fixup.
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. */
297 rtx before_jump;
298 /* The LABEL_DECL that this jump is jumping to, or 0
299 for break, continue or return. */
300 tree target;
301 /* The BLOCK for the place where this goto was found. */
302 tree context;
303 /* The CODE_LABEL rtx that this is jumping to. */
304 rtx target_rtl;
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. */
311 rtx stack_level;
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;
329 tree label;
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
340 or have cleanups. */
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. */
357 int x_nesting_depth;
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;
374 int x_emit_lineno;
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 *,
400 bool *, bool *));
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,
408 rtx, int));
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,
412 const char **));
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 *,
430 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 *));
438 void
439 using_eh_for_cleanups ()
441 using_eh_for_cleanups_p = 1;
444 void
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. */
450 block_stack = 0;
451 stack_block_stack = 0;
452 loop_stack = 0;
453 case_stack = 0;
454 cond_stack = 0;
455 nesting_stack = 0;
456 nesting_depth = 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;
465 clear_last_expr ();
468 /* Record the current file and line. Called from emit_line_note. */
469 void
470 set_file_and_line_for_stmt (file, line)
471 const char *file;
472 int 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
476 update it. */
477 if (cfun->stmt)
479 emit_filename = file;
480 emit_lineno = line;
484 /* Emit a no-op instruction. */
486 void
487 emit_nop ()
489 rtx last_insn;
491 last_insn = get_last_insn ();
492 if (!optimize
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. */
503 label_rtx (label)
504 tree label;
506 if (TREE_CODE (label) != LABEL_DECL)
507 abort ();
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. */
518 void
519 emit_jump (label)
520 rtx label;
522 do_pending_stack_adjust ();
523 emit_jump_insn (gen_jump (label));
524 emit_barrier ();
527 /* Emit code to jump to the address
528 specified by the pointer expression EXP. */
530 void
531 expand_computed_goto (exp)
532 tree 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);
539 #endif
541 emit_queue ();
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;
554 else
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. */
574 void
575 expand_label (label)
576 tree label;
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;
590 p->label = label;
594 /* Declare that LABEL (a LABEL_DECL) may be used for nonlocal gotos
595 from nested functions. */
597 void
598 declare_nonlocal_label (label)
599 tree 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'. */
619 void
620 expand_goto (label)
621 tree label;
623 tree context;
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;
632 tree link;
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,
655 static_chain));
657 /* Get addr of containing function's nonlocal save area. */
658 save_area = p->x_nonlocal_goto_stack_level;
659 if (save_area)
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));
667 else
668 #endif
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
686 non-local goto. */
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));
693 break;
695 else if (GET_CODE (insn) == CALL_INSN)
696 break;
699 else
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). */
708 static void
709 expand_goto_internal (body, label, last_insn)
710 tree body;
711 rtx label;
712 rtx last_insn;
714 struct nesting *block;
715 rtx stack_level = 0;
717 if (GET_CODE (label) != CODE_LABEL)
718 abort ();
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))
732 break;
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 ();
743 if (stack_level)
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))
755 == FUNCTION_TYPE)
756 && (TYPE_RETURNS_STACK_DEPRESSED
757 (TREE_TYPE (current_function_decl))))))
759 else
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. */
773 if (body != 0)
774 TREE_ADDRESSABLE (body) = 1;
777 emit_jump (label);
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. */
795 static int
796 expand_fixup (tree_label, rtl_label, last_insn)
797 tree tree_label;
798 rtx rtl_label;
799 rtx 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. */
808 if (cond_stack
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. */
815 else if (loop_stack
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;
820 else
821 end_block = 0;
823 /* Now set END_BLOCK to the binding level to which we will return. */
825 if (end_block)
827 struct nesting *next_block = end_block->all;
828 block = block_stack;
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;
835 if (next_block)
836 return 0;
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)
853 break;
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
865 someone does it! */
866 if (last_insn == 0)
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
881 as a placeholder. */
884 rtx original_before_jump
885 = last_insn ? last_insn : get_last_insn ();
886 rtx start;
887 rtx end;
888 tree block;
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);
895 else
897 BLOCK_CHAIN (block)
898 = BLOCK_CHAIN (DECL_INITIAL (current_function_decl));
899 BLOCK_CHAIN (DECL_INITIAL (current_function_decl))
900 = block;
903 start_sequence ();
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;
912 end_sequence ();
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)
923 : 0);
924 fixup->next = goto_fixup_chain;
925 goto_fixup_chain = fixup;
928 return block != 0;
931 /* Expand any needed fixups in the outputmost binding level of the
932 function. FIRST_INSN is the first insn in the function. */
934 void
935 expand_fixups (first_insn)
936 rtx 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. */
954 static void
955 fixup_gotos (thisblock, stack_level, cleanup_list, first_insn, dont_jump_in)
956 struct nesting *thisblock;
957 rtx stack_level;
958 tree cleanup_list;
959 rtx first_insn;
960 int dont_jump_in;
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
967 afterwards. */
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. */
975 if (prev != 0)
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)
982 rtx cleanup_insns;
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
992 around the label. */
993 if (f->target != 0
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. */
1009 start_sequence ();
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)
1021 tree lists;
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. */
1037 if (f->stack_level
1038 && ! (f->target_rtl == return_label
1039 && ((TREE_CODE (TREE_TYPE (current_function_decl))
1040 == FUNCTION_TYPE)
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);
1057 end_sequence ();
1058 emit_insn_after (cleanup_insns, f->before_jump);
1060 f->before_jump = 0;
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. */
1074 && thisblock != 0
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;
1081 rtx cleanup_insns;
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)
1088 start_sequence ();
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);
1095 end_sequence ();
1096 if (cleanup_insns != 0)
1097 f->before_jump
1098 = emit_insn_after (cleanup_insns, f->before_jump);
1100 f->cleanup_list_list = TREE_CHAIN (lists);
1103 if (stack_level)
1104 f->stack_level = stack_level;
1108 /* Return the number of times character C occurs in string S. */
1109 static int
1110 n_occurrences (c, s)
1111 int c;
1112 const char *s;
1114 int n = 0;
1115 while (*s)
1116 n += (*s++ == c);
1117 return n;
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. */
1125 void
1126 expand_asm (string, vol)
1127 tree string;
1128 int vol;
1130 rtx body;
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;
1139 emit_insn (body);
1141 clear_last_expr ();
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. */
1157 bool
1158 parse_output_constraint (constraint_p, operand_num, ninputs, noutputs,
1159 allows_mem, allows_reg, is_inout)
1160 const char **constraint_p;
1161 int operand_num;
1162 int ninputs;
1163 int noutputs;
1164 bool *allows_mem;
1165 bool *allows_reg;
1166 bool *is_inout;
1168 const char *constraint = *constraint_p;
1169 const char *p;
1171 /* Assume the constraint doesn't allow the use of either a register
1172 or memory. */
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, '=');
1181 if (!p)
1182 p = strchr (constraint, '+');
1184 /* If the string doesn't contain an `=', issue an error
1185 message. */
1186 if (!p)
1188 error ("output operand constraint lacks `='");
1189 return false;
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)
1199 char *buf;
1200 size_t c_len = strlen (constraint);
1202 if (p != constraint)
1203 warning ("output constraint `%c' for operand %d is not at the beginning",
1204 *p, operand_num);
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 `+'.) */
1213 buf[0] = '=';
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))
1221 switch (*p)
1223 case '+':
1224 case '=':
1225 error ("operand constraint contains incorrectly positioned '+' or '='");
1226 return false;
1228 case '%':
1229 if (operand_num + 1 == ninputs + noutputs)
1231 error ("`%%' constraint used with last operand");
1232 return false;
1234 break;
1236 case 'V': case 'm': case 'o':
1237 *allows_mem = true;
1238 break;
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 ',':
1245 break;
1247 case '0': case '1': case '2': case '3': case '4':
1248 case '5': case '6': case '7': case '8': case '9':
1249 case '[':
1250 error ("matching constraint not valid in output operand");
1251 return false;
1253 case '<': case '>':
1254 /* ??? Before flow, auto inc/dec insns are not supposed to exist,
1255 excepting those that expand_call created. So match memory
1256 and hope. */
1257 *allows_mem = true;
1258 break;
1260 case 'g': case 'X':
1261 *allows_reg = true;
1262 *allows_mem = true;
1263 break;
1265 case 'p': case 'r':
1266 *allows_reg = true;
1267 break;
1269 default:
1270 if (!ISALPHA (*p))
1271 break;
1272 if (REG_CLASS_FROM_CONSTRAINT (*p, p) != NO_REGS)
1273 *allows_reg = true;
1274 #ifdef EXTRA_CONSTRAINT_STR
1275 else if (EXTRA_ADDRESS_CONSTRAINT (*p, p))
1276 *allows_reg = true;
1277 else if (EXTRA_MEMORY_CONSTRAINT (*p, p))
1278 *allows_mem = true;
1279 else
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. */
1284 *allows_reg = true;
1285 *allows_mem = true;
1287 #endif
1288 break;
1291 return true;
1294 /* Similar, but for input constraints. */
1296 static bool
1297 parse_input_constraint (constraint_p, input_num, ninputs, noutputs, ninout,
1298 constraints, allows_mem, allows_reg)
1299 const char **constraint_p;
1300 int input_num;
1301 int ninputs;
1302 int noutputs;
1303 int ninout;
1304 const char * const * constraints;
1305 bool *allows_mem;
1306 bool *allows_reg;
1308 const char *constraint = *constraint_p;
1309 const char *orig_constraint = constraint;
1310 size_t c_len = strlen (constraint);
1311 size_t j;
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]);
1327 return false;
1329 break;
1331 case '%':
1332 if (constraint == orig_constraint
1333 && input_num + 1 == ninputs - ninout)
1335 error ("`%%' constraint used with last operand");
1336 return false;
1338 break;
1340 case 'V': case 'm': case 'o':
1341 *allows_mem = true;
1342 break;
1344 case '<': case '>':
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 ',':
1350 break;
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':
1360 char *end;
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");
1367 return false;
1370 /* Try and find the real constraint for this dup. Only do this
1371 if the matching constraint is the only alternative. */
1372 if (*end == '\0'
1373 && (j == 0 || (j == 1 && constraint[0] == '%')))
1375 constraint = constraints[match];
1376 *constraint_p = constraint;
1377 c_len = strlen (constraint);
1378 j = 0;
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. */
1383 break;
1385 else
1386 j = end - constraint;
1387 /* Anticipate increment at end of loop. */
1388 j--;
1390 /* Fall through. */
1392 case 'p': case 'r':
1393 *allows_reg = true;
1394 break;
1396 case 'g': case 'X':
1397 *allows_reg = true;
1398 *allows_mem = true;
1399 break;
1401 default:
1402 if (! ISALPHA (constraint[j]))
1404 error ("invalid punctuation `%c' in constraint", constraint[j]);
1405 return false;
1407 if (REG_CLASS_FROM_CONSTRAINT (constraint[j], constraint + j)
1408 != NO_REGS)
1409 *allows_reg = true;
1410 #ifdef EXTRA_CONSTRAINT_STR
1411 else if (EXTRA_ADDRESS_CONSTRAINT (constraint[j], constraint + j))
1412 *allows_reg = true;
1413 else if (EXTRA_MEMORY_CONSTRAINT (constraint[j], constraint + j))
1414 *allows_mem = true;
1415 else
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. */
1420 *allows_reg = true;
1421 *allows_mem = true;
1423 #endif
1424 break;
1427 return true;
1430 /* Check for overlap between registers marked in CLOBBERED_REGS and
1431 anything inappropriate in DECL. Emit error and return TRUE for error,
1432 FALSE for ok. */
1434 static bool
1435 decl_conflicts_with_clobbers_p (decl, clobbered_regs)
1436 tree decl;
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);
1447 unsigned int regno;
1449 for (regno = REGNO (reg);
1450 regno < (REGNO (reg)
1451 + HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg)));
1452 regno++)
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
1459 single variable. */
1460 DECL_REGISTER (decl) = 0;
1461 return true;
1464 return false;
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
1473 in TREE_PURPOSE.
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
1480 specified lvalues.
1482 VOL nonzero means the insn is volatile; don't optimize it. */
1484 void
1485 expand_asm_operands (string, outputs, inputs, clobbers, vol, filename, line)
1486 tree string, outputs, inputs, clobbers;
1487 int vol;
1488 const char *filename;
1489 int line;
1491 rtvec argvec, constraintvec;
1492 rtx body;
1493 int ninputs = list_length (inputs);
1494 int noutputs = list_length (outputs);
1495 int ninout;
1496 int nclobbers;
1497 HARD_REG_SET clobbered_regs;
1498 int clobber_conflict_found = 0;
1499 tree tail;
1500 int i;
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. */
1512 if (noutputs == 0)
1513 vol = 1;
1515 if (! check_operand_nalternatives (outputs, inputs))
1516 return;
1518 if (! check_unique_operand_names (outputs, inputs))
1519 return;
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);
1529 #endif
1531 /* Count the number of meaningful clobbered registers, ignoring what
1532 we would ignore later. */
1533 nclobbers = 0;
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)
1541 ++nclobbers;
1542 else if (i == -2)
1543 error ("unknown register name `%s' in `asm'", regname);
1545 /* Mark clobbered registers. */
1546 if (i >= 0)
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);
1552 return;
1555 SET_HARD_REG_BIT (clobbered_regs, i);
1559 clear_last_expr ();
1561 /* First pass over inputs and outputs checks validity and sets
1562 mark_addressable if needed. */
1564 ninout = 0;
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;
1570 bool is_inout;
1571 bool allows_reg;
1572 bool allows_mem;
1574 /* If there's an erroneous arg, emit no insn. */
1575 if (type == error_mark_node)
1576 return;
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))
1583 return;
1585 if (! allows_reg
1586 && (allows_mem
1587 || is_inout
1588 || (DECL_P (val)
1589 && GET_CODE (DECL_RTL (val)) == REG
1590 && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type))))
1591 (*lang_hooks.mark_addressable) (val);
1593 if (is_inout)
1594 ninout++;
1597 ninputs += ninout;
1598 if (ninputs + noutputs > MAX_RECOG_OPERANDS)
1600 error ("more than %d operands in `asm'", MAX_RECOG_OPERANDS);
1601 return;
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)
1612 return;
1614 constraint = constraints[i + noutputs];
1615 if (! parse_input_constraint (&constraint, i, ninputs, noutputs, ninout,
1616 constraints, &allows_mem, &allows_reg))
1617 return;
1619 if (! allows_reg && allows_mem)
1620 (*lang_hooks.mark_addressable) (TREE_VALUE (tail));
1623 /* Second pass evaluates arguments. */
1625 ninout = 0;
1626 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1628 tree val = TREE_VALUE (tail);
1629 tree type = TREE_TYPE (val);
1630 bool is_inout;
1631 bool allows_reg;
1632 bool allows_mem;
1633 rtx op;
1635 if (!parse_output_constraint (&constraints[i], i, ninputs,
1636 noutputs, &allows_mem, &allows_reg,
1637 &is_inout))
1638 abort ();
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
1649 && allows_mem)
1650 || (DECL_P (val)
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)))
1654 || ! allows_reg
1655 || is_inout)
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));
1668 if (is_inout)
1669 emit_move_insn (op, real_output_rtx[i]);
1672 else
1674 op = assign_temp (type, 0, 0, 1);
1675 op = validize_mem (op);
1676 TREE_VALUE (tail) = make_tree (type, op);
1678 output_rtx[i] = op;
1680 generating_concat_p = old_generating_concat_p;
1682 if (is_inout)
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,
1702 filename, line);
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;
1713 tree val, type;
1714 rtx op;
1716 constraint = constraints[i + noutputs];
1717 if (! parse_input_constraint (&constraint, i, ninputs, noutputs, ninout,
1718 constraints, &allows_mem, &allows_reg))
1719 abort ();
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)
1735 if (allows_reg)
1736 op = force_reg (TYPE_MODE (type), op);
1737 else if (!allows_mem)
1738 warning ("asm operand %d probably doesn't match constraints",
1739 i + noutputs);
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,
1751 (TYPE_QUALS (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);
1756 op = memloc;
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))
1766 else
1767 /* ??? Leave this only until we have experience with what
1768 happens in combine and elsewhere when constraints are
1769 not satisfied. */
1770 warning ("asm operand %d probably doesn't match constraints",
1771 i + noutputs);
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
1785 evaluated. */
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];
1800 char buffer[16];
1802 ASM_OPERANDS_INPUT (body, ninputs - ninout + i)
1803 = output_rtx[j];
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. */
1826 emit_insn (body);
1829 else
1831 rtx obody = body;
1832 int num = noutputs;
1834 if (num == 0)
1835 num = 1;
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,
1844 output_rtx[i],
1845 gen_rtx_ASM_OPERANDS
1846 (GET_MODE (output_rtx[i]),
1847 TREE_STRING_POINTER (string),
1848 constraints[i], i, argvec, constraintvec,
1849 filename, line));
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. */
1857 if (i == 0)
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);
1866 rtx clobbered_reg;
1868 if (j < 0)
1870 if (j == -3) /* `cc', which is not a register */
1871 continue;
1873 if (j == -4) /* `memory', don't cache memory across asm */
1875 XVECEXP (body, 0, i++)
1876 = gen_rtx_CLOBBER (VOIDmode,
1877 gen_rtx_MEM
1878 (BLKmode,
1879 gen_rtx_SCRATCH (VOIDmode)));
1880 continue;
1883 /* Ignore unknown register, error already signaled. */
1884 continue;
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)
1895 int opno;
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);
1913 emit_insn (body);
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]);
1922 free_temp_slots ();
1925 /* A subroutine of expand_asm_operands. Check that all operands have
1926 the same number of alternatives. Return true if so. */
1928 static bool
1929 check_operand_nalternatives (outputs, inputs)
1930 tree outputs, inputs;
1932 if (outputs || inputs)
1934 tree tmp = TREE_PURPOSE (outputs ? outputs : inputs);
1935 int nalternatives
1936 = n_occurrences (',', TREE_STRING_POINTER (TREE_VALUE (tmp)));
1937 tree next = inputs;
1939 if (nalternatives + 1 > MAX_RECOG_ALTERNATIVES)
1941 error ("too many alternatives in `asm'");
1942 return false;
1945 tmp = outputs;
1946 while (tmp)
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");
1954 return false;
1957 if (TREE_CHAIN (tmp))
1958 tmp = TREE_CHAIN (tmp);
1959 else
1960 tmp = next, next = 0;
1964 return true;
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. */
1972 static bool
1973 check_unique_operand_names (outputs, inputs)
1974 tree outputs, inputs;
1976 tree i, j;
1978 for (i = outputs; i ; i = TREE_CHAIN (i))
1980 tree i_name = TREE_PURPOSE (TREE_PURPOSE (i));
1981 if (! i_name)
1982 continue;
1984 for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
1985 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1986 goto failure;
1989 for (i = inputs; i ; i = TREE_CHAIN (i))
1991 tree i_name = TREE_PURPOSE (TREE_PURPOSE (i));
1992 if (! i_name)
1993 continue;
1995 for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
1996 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1997 goto failure;
1998 for (j = outputs; j ; j = TREE_CHAIN (j))
1999 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
2000 goto failure;
2003 return true;
2005 failure:
2006 error ("duplicate asm operand name '%s'",
2007 TREE_STRING_POINTER (TREE_PURPOSE (TREE_PURPOSE (i))));
2008 return false;
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. */
2015 static tree
2016 resolve_operand_names (string, outputs, inputs, pconstraints)
2017 tree string;
2018 tree outputs, inputs;
2019 const char **pconstraints;
2021 char *buffer = xstrdup (TREE_STRING_POINTER (string));
2022 char *p;
2023 tree t;
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. */
2029 p = buffer;
2030 while ((p = strchr (p, '%')) != NULL)
2032 if (p[1] == '[')
2033 p += 1;
2034 else if (ISALPHA (p[1]) && p[2] == '[')
2035 p += 2;
2036 else
2038 p += 1;
2039 continue;
2042 p = resolve_operand_name_1 (p, outputs, inputs);
2045 string = build_string (strlen (buffer), buffer);
2046 free (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)
2059 *pconstraints = c;
2060 else
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);
2067 free (buffer);
2071 return string;
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. */
2079 static char *
2080 resolve_operand_name_1 (p, outputs, inputs)
2081 char *p;
2082 tree outputs, inputs;
2084 char *q;
2085 int op;
2086 tree t;
2087 size_t len;
2089 /* Collect the operand name. */
2090 q = strchr (p, ']');
2091 if (!q)
2093 error ("missing close brace for named operand");
2094 return strchr (p, '\0');
2096 len = q - p - 1;
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));
2102 if (name)
2104 const char *c = TREE_STRING_POINTER (name);
2105 if (strncmp (c, p + 1, len) == 0 && c[len] == '\0')
2106 goto found;
2109 for (t = inputs; t ; t = TREE_CHAIN (t), op++)
2111 tree name = TREE_PURPOSE (TREE_PURPOSE (t));
2112 if (name)
2114 const char *c = TREE_STRING_POINTER (name);
2115 if (strncmp (c, p + 1, len) == 0 && c[len] == '\0')
2116 goto found;
2120 *q = '\0';
2121 error ("undefined named operand '%s'", p + 1);
2122 op = 0;
2123 found:
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. */
2132 if (p > q)
2133 abort ();
2135 /* Shift the rest of the buffer down to fill the gap. */
2136 memmove (p, q + 1, strlen (q + 1) + 1);
2138 return p;
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. */
2146 void
2147 expand_expr_stmt (exp)
2148 tree 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. */
2158 void
2159 expand_expr_stmt_value (exp, want_value, maybe_last)
2160 tree exp;
2161 int want_value, maybe_last;
2163 rtx value;
2164 tree type;
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. */
2172 if (! want_value
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,
2197 VOIDmode, 0);
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);
2208 else
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),
2216 BLKmode, 0, lab);
2217 emit_label (lab);
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
2227 above. */
2228 free_temp_slots ();
2230 if (want_value)
2232 last_expr_value = value;
2233 last_expr_type = type;
2236 emit_queue ();
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)
2244 tree exp;
2246 if (TREE_USED (exp))
2247 return 0;
2249 /* Don't warn about void constructs. This includes casting to void,
2250 void function calls, and statement expressions with a final cast
2251 to void. */
2252 if (VOID_TYPE_P (TREE_TYPE (exp)))
2253 return 0;
2255 switch (TREE_CODE (exp))
2257 case PREINCREMENT_EXPR:
2258 case POSTINCREMENT_EXPR:
2259 case PREDECREMENT_EXPR:
2260 case POSTDECREMENT_EXPR:
2261 case MODIFY_EXPR:
2262 case INIT_EXPR:
2263 case TARGET_EXPR:
2264 case CALL_EXPR:
2265 case METHOD_CALL_EXPR:
2266 case RTL_EXPR:
2267 case TRY_CATCH_EXPR:
2268 case WITH_CLEANUP_EXPR:
2269 case EXIT_EXPR:
2270 return 0;
2272 case BIND_EXPR:
2273 /* For a binding, warn if no side effect within it. */
2274 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2276 case SAVE_EXPR:
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));
2284 case COMPOUND_EXPR:
2285 if (TREE_NO_UNUSED_WARNING (exp))
2286 return 0;
2287 if (warn_if_unused_value (TREE_OPERAND (exp, 0)))
2288 return 1;
2289 /* Let people do `(foo (), 0)' without a warning. */
2290 if (TREE_CONSTANT (TREE_OPERAND (exp, 1)))
2291 return 0;
2292 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2294 case NOP_EXPR:
2295 case CONVERT_EXPR:
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))
2299 return 0;
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)
2312 return 0;
2314 goto maybe_warn;
2316 case INDIRECT_REF:
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));
2321 /* Fall through. */
2323 default:
2324 /* Referencing a volatile value is a side effect, so don't warn. */
2325 if ((DECL_P (exp)
2326 || TREE_CODE_CLASS (TREE_CODE (exp)) == 'r')
2327 && TREE_THIS_VOLATILE (exp))
2328 return 0;
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)
2335 return 0;
2337 maybe_warn:
2338 /* If this is an expression with side effects, don't warn. */
2339 if (TREE_SIDE_EFFECTS (exp))
2340 return 0;
2342 warning_with_file_and_line (emit_filename, emit_lineno,
2343 "value computed is not used");
2344 return 1;
2348 /* Clear out the memory of the last expression evaluated. */
2350 void
2351 clear_last_expr ()
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
2362 expression. */
2364 tree
2365 expand_start_stmt_expr (has_scope)
2366 int has_scope;
2368 tree t;
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 ();
2374 if (has_scope)
2375 start_sequence_for_rtl_expr (t);
2376 else
2377 start_sequence ();
2378 NO_DEFER_POP;
2379 expr_stmts_for_value++;
2380 return t;
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'. */
2395 tree
2396 expand_end_stmt_expr (t)
2397 tree t;
2399 OK_DEFER_POP;
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);
2410 emit_queue ();
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);
2418 end_sequence ();
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);
2425 clear_last_expr ();
2426 expr_stmts_for_value--;
2428 return t;
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'. */
2437 void
2438 expand_start_cond (cond, exitflag)
2439 tree cond;
2440 int 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-.... */
2465 void
2466 expand_start_elseif (cond)
2467 tree 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. */
2480 void
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. */
2494 void
2495 expand_elseif (cond)
2496 tree 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. */
2505 void
2506 expand_end_cond ()
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);
2517 clear_last_expr ();
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
2525 this loop. */
2527 struct nesting *
2528 expand_start_loop (exit_flag)
2529 int 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 ();
2547 emit_queue ();
2548 emit_note (NULL, NOTE_INSN_LOOP_BEG);
2549 emit_label (thisloop->data.loop.start_label);
2551 return thisloop;
2554 /* Like expand_start_loop but for a loop where the continuation point
2555 (for expand_continue_loop) will be specified explicitly. */
2557 struct nesting *
2558 expand_start_loop_continue_elsewhere (exit_flag)
2559 int exit_flag;
2561 struct nesting *thisloop = expand_start_loop (exit_flag);
2562 loop_stack->data.loop.continue_label = gen_label_rtx ();
2563 return thisloop;
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. */
2569 struct nesting *
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;
2587 return 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
2593 should jump. */
2595 void
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. */
2606 void
2607 expand_end_loop ()
2609 rtx start_label = loop_stack->data.loop.start_label;
2610 rtx etc_note;
2611 int eh_regions, debug_blocks;
2612 bool empty_test;
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):
2625 LOOP_BEG
2626 start_label:
2627 if (test) goto end_label;
2628 LOOP_END_TOP_COND
2629 body;
2630 goto start_label;
2631 end_label:
2633 transform it to look like:
2635 LOOP_BEG
2636 goto start_label;
2637 top_label:
2638 body;
2639 start_label:
2640 if (test) goto end_label;
2641 goto top_label;
2642 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. */
2656 empty_test = true;
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)
2662 break;
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;
2668 break;
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)
2674 eh_regions++;
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. */
2685 abort ();
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)
2693 debug_blocks++;
2694 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_BLOCK_END)
2695 debug_blocks--;
2697 else if (INSN_P (etc_note))
2698 empty_test = false;
2700 if (etc_note
2701 && optimize
2702 && ! empty_test
2703 && eh_regions == 0
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 ());
2726 else
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))
2738 continue;
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);
2756 clear_last_expr ();
2759 /* Finish a null loop, aka do { } while (0). */
2761 void
2762 expand_end_null_loop ()
2764 do_pending_stack_adjust ();
2765 emit_label (loop_stack->data.loop.end_label);
2767 POPSTACK (loop_stack);
2769 clear_last_expr ();
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. */
2782 rtx note;
2784 if (flag_guess_branch_prob)
2786 note = emit_note (NULL, NOTE_INSN_PREDICTION);
2787 NOTE_PREDICTION (note) = NOTE_PREDICT (PRED_CONTINUE, IS_TAKEN);
2789 clear_last_expr ();
2790 if (whichloop == 0)
2791 whichloop = loop_stack;
2792 if (whichloop == 0)
2793 return 0;
2794 expand_goto_internal (NULL_TREE, whichloop->data.loop.continue_label,
2795 NULL_RTX);
2796 return 1;
2799 /* Generate a jump to exit the current loop. If not currently inside a loop,
2800 return 0 and do nothing; caller will print an error message. */
2803 expand_exit_loop (whichloop)
2804 struct nesting *whichloop;
2806 clear_last_expr ();
2807 if (whichloop == 0)
2808 whichloop = loop_stack;
2809 if (whichloop == 0)
2810 return 0;
2811 expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label, NULL_RTX);
2812 return 1;
2815 /* Generate a conditional jump to exit the current loop if COND
2816 evaluates to zero. If not currently inside a loop,
2817 return 0 and do nothing; caller will print an error message. */
2820 expand_exit_loop_if_false (whichloop, cond)
2821 struct nesting *whichloop;
2822 tree cond;
2824 rtx label;
2825 clear_last_expr ();
2827 if (whichloop == 0)
2828 whichloop = loop_stack;
2829 if (whichloop == 0)
2830 return 0;
2832 if (integer_nonzerop (cond))
2833 return 1;
2834 if (integer_zerop (cond))
2835 return expand_exit_loop (whichloop);
2837 /* Check if we definitely won't need a fixup. */
2838 if (whichloop == nesting_stack)
2840 jumpifnot (cond, whichloop->data.loop.end_label);
2841 return 1;
2844 /* In order to handle fixups, we actually create a conditional jump
2845 around an unconditional branch to exit the loop. If fixups are
2846 necessary, they go before the unconditional branch. */
2848 label = gen_label_rtx ();
2849 jumpif (cond, label);
2850 expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label,
2851 NULL_RTX);
2852 emit_label (label);
2854 return 1;
2857 /* Like expand_exit_loop_if_false except also emit a note marking
2858 the end of the conditional. Should only be used immediately
2859 after expand_loop_start. */
2862 expand_exit_loop_top_cond (whichloop, cond)
2863 struct nesting *whichloop;
2864 tree cond;
2866 if (! expand_exit_loop_if_false (whichloop, cond))
2867 return 0;
2869 emit_note (NULL, NOTE_INSN_LOOP_END_TOP_COND);
2870 return 1;
2873 /* Return nonzero if we should preserve sub-expressions as separate
2874 pseudos. We never do so if we aren't optimizing. We always do so
2875 if -fexpensive-optimizations.
2877 Otherwise, we only do so if we are in the "early" part of a loop. I.e.,
2878 the loop may still be a small one. */
2881 preserve_subexpressions_p ()
2883 rtx insn;
2885 if (flag_expensive_optimizations)
2886 return 1;
2888 if (optimize == 0 || cfun == 0 || cfun->stmt == 0 || loop_stack == 0)
2889 return 0;
2891 insn = get_last_insn_anywhere ();
2893 return (insn
2894 && (INSN_UID (insn) - INSN_UID (loop_stack->data.loop.start_label)
2895 < n_non_fixed_regs * 3));
2899 /* Generate a jump to exit the current loop, conditional, binding contour
2900 or case statement. Not all such constructs are visible to this function,
2901 only those started with EXIT_FLAG nonzero. Individual languages use
2902 the EXIT_FLAG parameter to control which kinds of constructs you can
2903 exit this way.
2905 If not currently inside anything that can be exited,
2906 return 0 and do nothing; caller will print an error message. */
2909 expand_exit_something ()
2911 struct nesting *n;
2912 clear_last_expr ();
2913 for (n = nesting_stack; n; n = n->all)
2914 if (n->exit_label != 0)
2916 expand_goto_internal (NULL_TREE, n->exit_label, NULL_RTX);
2917 return 1;
2920 return 0;
2923 /* Generate RTL to return from the current function, with no value.
2924 (That is, we do not do anything about returning any value.) */
2926 void
2927 expand_null_return ()
2929 rtx last_insn;
2931 last_insn = get_last_insn ();
2933 /* If this function was declared to return a value, but we
2934 didn't, clobber the return registers so that they are not
2935 propagated live to the rest of the function. */
2936 clobber_return_register ();
2938 expand_null_return_1 (last_insn);
2941 /* Try to guess whether the value of return means error code. */
2942 static enum br_predictor
2943 return_prediction (val)
2944 rtx val;
2946 /* Different heuristics for pointers and scalars. */
2947 if (POINTER_TYPE_P (TREE_TYPE (DECL_RESULT (current_function_decl))))
2949 /* NULL is usually not returned. */
2950 if (val == const0_rtx)
2951 return PRED_NULL_RETURN;
2953 else
2955 /* Negative return values are often used to indicate
2956 errors. */
2957 if (GET_CODE (val) == CONST_INT
2958 && INTVAL (val) < 0)
2959 return PRED_NEGATIVE_RETURN;
2960 /* Constant return values are also usually erors,
2961 zero/one often mean booleans so exclude them from the
2962 heuristics. */
2963 if (CONSTANT_P (val)
2964 && (val != const0_rtx && val != const1_rtx))
2965 return PRED_CONST_RETURN;
2967 return PRED_NO_PREDICTION;
2970 /* Generate RTL to return from the current function, with value VAL. */
2972 static void
2973 expand_value_return (val)
2974 rtx val;
2976 rtx last_insn;
2977 rtx return_reg;
2978 enum br_predictor pred;
2980 if (flag_guess_branch_prob
2981 && (pred = return_prediction (val)) != PRED_NO_PREDICTION)
2983 /* Emit information for branch prediction. */
2984 rtx note;
2986 note = emit_note (NULL, NOTE_INSN_PREDICTION);
2988 NOTE_PREDICTION (note) = NOTE_PREDICT (pred, NOT_TAKEN);
2992 last_insn = get_last_insn ();
2993 return_reg = DECL_RTL (DECL_RESULT (current_function_decl));
2995 /* Copy the value to the return location
2996 unless it's already there. */
2998 if (return_reg != val)
3000 tree type = TREE_TYPE (DECL_RESULT (current_function_decl));
3001 #ifdef PROMOTE_FUNCTION_RETURN
3002 int unsignedp = TREE_UNSIGNED (type);
3003 enum machine_mode old_mode
3004 = DECL_MODE (DECL_RESULT (current_function_decl));
3005 enum machine_mode mode
3006 = promote_mode (type, old_mode, &unsignedp, 1);
3008 if (mode != old_mode)
3009 val = convert_modes (mode, old_mode, val, unsignedp);
3010 #endif
3011 if (GET_CODE (return_reg) == PARALLEL)
3012 emit_group_load (return_reg, val, int_size_in_bytes (type));
3013 else
3014 emit_move_insn (return_reg, val);
3017 expand_null_return_1 (last_insn);
3020 /* Output a return with no value. If LAST_INSN is nonzero,
3021 pretend that the return takes place after LAST_INSN. */
3023 static void
3024 expand_null_return_1 (last_insn)
3025 rtx last_insn;
3027 rtx end_label = cleanup_label ? cleanup_label : return_label;
3029 clear_pending_stack_adjust ();
3030 do_pending_stack_adjust ();
3031 clear_last_expr ();
3033 if (end_label == 0)
3034 end_label = return_label = gen_label_rtx ();
3035 expand_goto_internal (NULL_TREE, end_label, last_insn);
3038 /* Generate RTL to evaluate the expression RETVAL and return it
3039 from the current function. */
3041 void
3042 expand_return (retval)
3043 tree retval;
3045 /* If there are any cleanups to be performed, then they will
3046 be inserted following LAST_INSN. It is desirable
3047 that the last_insn, for such purposes, should be the
3048 last insn before computing the return value. Otherwise, cleanups
3049 which call functions can clobber the return value. */
3050 /* ??? rms: I think that is erroneous, because in C++ it would
3051 run destructors on variables that might be used in the subsequent
3052 computation of the return value. */
3053 rtx last_insn = 0;
3054 rtx result_rtl;
3055 rtx val = 0;
3056 tree retval_rhs;
3058 /* If function wants no value, give it none. */
3059 if (TREE_CODE (TREE_TYPE (TREE_TYPE (current_function_decl))) == VOID_TYPE)
3061 expand_expr (retval, NULL_RTX, VOIDmode, 0);
3062 emit_queue ();
3063 expand_null_return ();
3064 return;
3067 if (retval == error_mark_node)
3069 /* Treat this like a return of no value from a function that
3070 returns a value. */
3071 expand_null_return ();
3072 return;
3074 else if (TREE_CODE (retval) == RESULT_DECL)
3075 retval_rhs = retval;
3076 else if ((TREE_CODE (retval) == MODIFY_EXPR || TREE_CODE (retval) == INIT_EXPR)
3077 && TREE_CODE (TREE_OPERAND (retval, 0)) == RESULT_DECL)
3078 retval_rhs = TREE_OPERAND (retval, 1);
3079 else if (VOID_TYPE_P (TREE_TYPE (retval)))
3080 /* Recognize tail-recursive call to void function. */
3081 retval_rhs = retval;
3082 else
3083 retval_rhs = NULL_TREE;
3085 last_insn = get_last_insn ();
3087 /* Distribute return down conditional expr if either of the sides
3088 may involve tail recursion (see test below). This enhances the number
3089 of tail recursions we see. Don't do this always since it can produce
3090 sub-optimal code in some cases and we distribute assignments into
3091 conditional expressions when it would help. */
3093 if (optimize && retval_rhs != 0
3094 && frame_offset == 0
3095 && TREE_CODE (retval_rhs) == COND_EXPR
3096 && (TREE_CODE (TREE_OPERAND (retval_rhs, 1)) == CALL_EXPR
3097 || TREE_CODE (TREE_OPERAND (retval_rhs, 2)) == CALL_EXPR))
3099 rtx label = gen_label_rtx ();
3100 tree expr;
3102 do_jump (TREE_OPERAND (retval_rhs, 0), label, NULL_RTX);
3103 start_cleanup_deferral ();
3104 expr = build (MODIFY_EXPR, TREE_TYPE (TREE_TYPE (current_function_decl)),
3105 DECL_RESULT (current_function_decl),
3106 TREE_OPERAND (retval_rhs, 1));
3107 TREE_SIDE_EFFECTS (expr) = 1;
3108 expand_return (expr);
3109 emit_label (label);
3111 expr = build (MODIFY_EXPR, TREE_TYPE (TREE_TYPE (current_function_decl)),
3112 DECL_RESULT (current_function_decl),
3113 TREE_OPERAND (retval_rhs, 2));
3114 TREE_SIDE_EFFECTS (expr) = 1;
3115 expand_return (expr);
3116 end_cleanup_deferral ();
3117 return;
3120 result_rtl = DECL_RTL (DECL_RESULT (current_function_decl));
3122 /* If the result is an aggregate that is being returned in one (or more)
3123 registers, load the registers here. The compiler currently can't handle
3124 copying a BLKmode value into registers. We could put this code in a
3125 more general area (for use by everyone instead of just function
3126 call/return), but until this feature is generally usable it is kept here
3127 (and in expand_call). The value must go into a pseudo in case there
3128 are cleanups that will clobber the real return register. */
3130 if (retval_rhs != 0
3131 && TYPE_MODE (TREE_TYPE (retval_rhs)) == BLKmode
3132 && GET_CODE (result_rtl) == REG)
3134 int i;
3135 unsigned HOST_WIDE_INT bitpos, xbitpos;
3136 unsigned HOST_WIDE_INT big_endian_correction = 0;
3137 unsigned HOST_WIDE_INT bytes
3138 = int_size_in_bytes (TREE_TYPE (retval_rhs));
3139 int n_regs = (bytes + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
3140 unsigned int bitsize
3141 = MIN (TYPE_ALIGN (TREE_TYPE (retval_rhs)), BITS_PER_WORD);
3142 rtx *result_pseudos = (rtx *) alloca (sizeof (rtx) * n_regs);
3143 rtx result_reg, src = NULL_RTX, dst = NULL_RTX;
3144 rtx result_val = expand_expr (retval_rhs, NULL_RTX, VOIDmode, 0);
3145 enum machine_mode tmpmode, result_reg_mode;
3147 if (bytes == 0)
3149 expand_null_return ();
3150 return;
3153 /* Structures whose size is not a multiple of a word are aligned
3154 to the least significant byte (to the right). On a BYTES_BIG_ENDIAN
3155 machine, this means we must skip the empty high order bytes when
3156 calculating the bit offset. */
3157 if (BYTES_BIG_ENDIAN
3158 && bytes % UNITS_PER_WORD)
3159 big_endian_correction = (BITS_PER_WORD - ((bytes % UNITS_PER_WORD)
3160 * BITS_PER_UNIT));
3162 /* Copy the structure BITSIZE bits at a time. */
3163 for (bitpos = 0, xbitpos = big_endian_correction;
3164 bitpos < bytes * BITS_PER_UNIT;
3165 bitpos += bitsize, xbitpos += bitsize)
3167 /* We need a new destination pseudo each time xbitpos is
3168 on a word boundary and when xbitpos == big_endian_correction
3169 (the first time through). */
3170 if (xbitpos % BITS_PER_WORD == 0
3171 || xbitpos == big_endian_correction)
3173 /* Generate an appropriate register. */
3174 dst = gen_reg_rtx (word_mode);
3175 result_pseudos[xbitpos / BITS_PER_WORD] = dst;
3177 /* Clear the destination before we move anything into it. */
3178 emit_move_insn (dst, CONST0_RTX (GET_MODE (dst)));
3181 /* We need a new source operand each time bitpos is on a word
3182 boundary. */
3183 if (bitpos % BITS_PER_WORD == 0)
3184 src = operand_subword_force (result_val,
3185 bitpos / BITS_PER_WORD,
3186 BLKmode);
3188 /* Use bitpos for the source extraction (left justified) and
3189 xbitpos for the destination store (right justified). */
3190 store_bit_field (dst, bitsize, xbitpos % BITS_PER_WORD, word_mode,
3191 extract_bit_field (src, bitsize,
3192 bitpos % BITS_PER_WORD, 1,
3193 NULL_RTX, word_mode, word_mode,
3194 BITS_PER_WORD),
3195 BITS_PER_WORD);
3198 /* Find the smallest integer mode large enough to hold the
3199 entire structure and use that mode instead of BLKmode
3200 on the USE insn for the return register. */
3201 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
3202 tmpmode != VOIDmode;
3203 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
3204 /* Have we found a large enough mode? */
3205 if (GET_MODE_SIZE (tmpmode) >= bytes)
3206 break;
3208 /* No suitable mode found. */
3209 if (tmpmode == VOIDmode)
3210 abort ();
3212 PUT_MODE (result_rtl, tmpmode);
3214 if (GET_MODE_SIZE (tmpmode) < GET_MODE_SIZE (word_mode))
3215 result_reg_mode = word_mode;
3216 else
3217 result_reg_mode = tmpmode;
3218 result_reg = gen_reg_rtx (result_reg_mode);
3220 emit_queue ();
3221 for (i = 0; i < n_regs; i++)
3222 emit_move_insn (operand_subword (result_reg, i, 0, result_reg_mode),
3223 result_pseudos[i]);
3225 if (tmpmode != result_reg_mode)
3226 result_reg = gen_lowpart (tmpmode, result_reg);
3228 expand_value_return (result_reg);
3230 else if (retval_rhs != 0
3231 && !VOID_TYPE_P (TREE_TYPE (retval_rhs))
3232 && (GET_CODE (result_rtl) == REG
3233 || (GET_CODE (result_rtl) == PARALLEL)))
3235 /* Calculate the return value into a temporary (usually a pseudo
3236 reg). */
3237 tree ot = TREE_TYPE (DECL_RESULT (current_function_decl));
3238 tree nt = build_qualified_type (ot, TYPE_QUALS (ot) | TYPE_QUAL_CONST);
3240 val = assign_temp (nt, 0, 0, 1);
3241 val = expand_expr (retval_rhs, val, GET_MODE (val), 0);
3242 val = force_not_mem (val);
3243 emit_queue ();
3244 /* Return the calculated value, doing cleanups first. */
3245 expand_value_return (val);
3247 else
3249 /* No cleanups or no hard reg used;
3250 calculate value into hard return reg. */
3251 expand_expr (retval, const0_rtx, VOIDmode, 0);
3252 emit_queue ();
3253 expand_value_return (result_rtl);
3257 /* Attempt to optimize a potential tail recursion call into a goto.
3258 ARGUMENTS are the arguments to a CALL_EXPR; LAST_INSN indicates
3259 where to place the jump to the tail recursion label.
3261 Return TRUE if the call was optimized into a goto. */
3264 optimize_tail_recursion (arguments, last_insn)
3265 tree arguments;
3266 rtx last_insn;
3268 /* Finish checking validity, and if valid emit code to set the
3269 argument variables for the new call. */
3270 if (tail_recursion_args (arguments, DECL_ARGUMENTS (current_function_decl)))
3272 if (tail_recursion_label == 0)
3274 tail_recursion_label = gen_label_rtx ();
3275 emit_label_after (tail_recursion_label,
3276 tail_recursion_reentry);
3278 emit_queue ();
3279 expand_goto_internal (NULL_TREE, tail_recursion_label, last_insn);
3280 emit_barrier ();
3281 return 1;
3283 return 0;
3286 /* Emit code to alter this function's formal parms for a tail-recursive call.
3287 ACTUALS is a list of actual parameter expressions (chain of TREE_LISTs).
3288 FORMALS is the chain of decls of formals.
3289 Return 1 if this can be done;
3290 otherwise return 0 and do not emit any code. */
3292 static int
3293 tail_recursion_args (actuals, formals)
3294 tree actuals, formals;
3296 tree a = actuals, f = formals;
3297 int i;
3298 rtx *argvec;
3300 /* Check that number and types of actuals are compatible
3301 with the formals. This is not always true in valid C code.
3302 Also check that no formal needs to be addressable
3303 and that all formals are scalars. */
3305 /* Also count the args. */
3307 for (a = actuals, f = formals, i = 0; a && f; a = TREE_CHAIN (a), f = TREE_CHAIN (f), i++)
3309 if (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_VALUE (a)))
3310 != TYPE_MAIN_VARIANT (TREE_TYPE (f)))
3311 return 0;
3312 if (GET_CODE (DECL_RTL (f)) != REG || DECL_MODE (f) == BLKmode)
3313 return 0;
3315 if (a != 0 || f != 0)
3316 return 0;
3318 /* Compute all the actuals. */
3320 argvec = (rtx *) alloca (i * sizeof (rtx));
3322 for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
3323 argvec[i] = expand_expr (TREE_VALUE (a), NULL_RTX, VOIDmode, 0);
3325 /* Find which actual values refer to current values of previous formals.
3326 Copy each of them now, before any formal is changed. */
3328 for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
3330 int copy = 0;
3331 int j;
3332 for (f = formals, j = 0; j < i; f = TREE_CHAIN (f), j++)
3333 if (reg_mentioned_p (DECL_RTL (f), argvec[i]))
3335 copy = 1;
3336 break;
3338 if (copy)
3339 argvec[i] = copy_to_reg (argvec[i]);
3342 /* Store the values of the actuals into the formals. */
3344 for (f = formals, a = actuals, i = 0; f;
3345 f = TREE_CHAIN (f), a = TREE_CHAIN (a), i++)
3347 if (GET_MODE (DECL_RTL (f)) == GET_MODE (argvec[i]))
3348 emit_move_insn (DECL_RTL (f), argvec[i]);
3349 else
3351 rtx tmp = argvec[i];
3353 if (DECL_MODE (f) != GET_MODE (DECL_RTL (f)))
3355 tmp = gen_reg_rtx (DECL_MODE (f));
3356 convert_move (tmp, argvec[i],
3357 TREE_UNSIGNED (TREE_TYPE (TREE_VALUE (a))));
3359 convert_move (DECL_RTL (f), tmp,
3360 TREE_UNSIGNED (TREE_TYPE (TREE_VALUE (a))));
3364 free_temp_slots ();
3365 return 1;
3368 /* Generate the RTL code for entering a binding contour.
3369 The variables are declared one by one, by calls to `expand_decl'.
3371 FLAGS is a bitwise or of the following flags:
3373 1 - Nonzero if this construct should be visible to
3374 `exit_something'.
3376 2 - Nonzero if this contour does not require a
3377 NOTE_INSN_BLOCK_BEG note. Virtually all calls from
3378 language-independent code should set this flag because they
3379 will not create corresponding BLOCK nodes. (There should be
3380 a one-to-one correspondence between NOTE_INSN_BLOCK_BEG notes
3381 and BLOCKs.) If this flag is set, MARK_ENDS should be zero
3382 when expand_end_bindings is called.
3384 If we are creating a NOTE_INSN_BLOCK_BEG note, a BLOCK may
3385 optionally be supplied. If so, it becomes the NOTE_BLOCK for the
3386 note. */
3388 void
3389 expand_start_bindings_and_block (flags, block)
3390 int flags;
3391 tree block;
3393 struct nesting *thisblock = ALLOC_NESTING ();
3394 rtx note;
3395 int exit_flag = ((flags & 1) != 0);
3396 int block_flag = ((flags & 2) == 0);
3398 /* If a BLOCK is supplied, then the caller should be requesting a
3399 NOTE_INSN_BLOCK_BEG note. */
3400 if (!block_flag && block)
3401 abort ();
3403 /* Create a note to mark the beginning of the block. */
3404 if (block_flag)
3406 note = emit_note (NULL, NOTE_INSN_BLOCK_BEG);
3407 NOTE_BLOCK (note) = block;
3409 else
3410 note = emit_note (NULL, NOTE_INSN_DELETED);
3412 /* Make an entry on block_stack for the block we are entering. */
3414 thisblock->desc = BLOCK_NESTING;
3415 thisblock->next = block_stack;
3416 thisblock->all = nesting_stack;
3417 thisblock->depth = ++nesting_depth;
3418 thisblock->data.block.stack_level = 0;
3419 thisblock->data.block.cleanups = 0;
3420 thisblock->data.block.n_function_calls = 0;
3421 thisblock->data.block.exception_region = 0;
3422 thisblock->data.block.block_target_temp_slot_level = target_temp_slot_level;
3424 thisblock->data.block.conditional_code = 0;
3425 thisblock->data.block.last_unconditional_cleanup = note;
3426 /* When we insert instructions after the last unconditional cleanup,
3427 we don't adjust last_insn. That means that a later add_insn will
3428 clobber the instructions we've just added. The easiest way to
3429 fix this is to just insert another instruction here, so that the
3430 instructions inserted after the last unconditional cleanup are
3431 never the last instruction. */
3432 emit_note (NULL, NOTE_INSN_DELETED);
3434 if (block_stack
3435 && !(block_stack->data.block.cleanups == NULL_TREE
3436 && block_stack->data.block.outer_cleanups == NULL_TREE))
3437 thisblock->data.block.outer_cleanups
3438 = tree_cons (NULL_TREE, block_stack->data.block.cleanups,
3439 block_stack->data.block.outer_cleanups);
3440 else
3441 thisblock->data.block.outer_cleanups = 0;
3442 thisblock->data.block.label_chain = 0;
3443 thisblock->data.block.innermost_stack_block = stack_block_stack;
3444 thisblock->data.block.first_insn = note;
3445 thisblock->data.block.block_start_count = ++current_block_start_count;
3446 thisblock->exit_label = exit_flag ? gen_label_rtx () : 0;
3447 block_stack = thisblock;
3448 nesting_stack = thisblock;
3450 /* Make a new level for allocating stack slots. */
3451 push_temp_slots ();
3454 /* Specify the scope of temporaries created by TARGET_EXPRs. Similar
3455 to CLEANUP_POINT_EXPR, but handles cases when a series of calls to
3456 expand_expr are made. After we end the region, we know that all
3457 space for all temporaries that were created by TARGET_EXPRs will be
3458 destroyed and their space freed for reuse. */
3460 void
3461 expand_start_target_temps ()
3463 /* This is so that even if the result is preserved, the space
3464 allocated will be freed, as we know that it is no longer in use. */
3465 push_temp_slots ();
3467 /* Start a new binding layer that will keep track of all cleanup
3468 actions to be performed. */
3469 expand_start_bindings (2);
3471 target_temp_slot_level = temp_slot_level;
3474 void
3475 expand_end_target_temps ()
3477 expand_end_bindings (NULL_TREE, 0, 0);
3479 /* This is so that even if the result is preserved, the space
3480 allocated will be freed, as we know that it is no longer in use. */
3481 pop_temp_slots ();
3484 /* Given a pointer to a BLOCK node return nonzero if (and only if) the node
3485 in question represents the outermost pair of curly braces (i.e. the "body
3486 block") of a function or method.
3488 For any BLOCK node representing a "body block" of a function or method, the
3489 BLOCK_SUPERCONTEXT of the node will point to another BLOCK node which
3490 represents the outermost (function) scope for the function or method (i.e.
3491 the one which includes the formal parameters). The BLOCK_SUPERCONTEXT of
3492 *that* node in turn will point to the relevant FUNCTION_DECL node. */
3495 is_body_block (stmt)
3496 tree stmt;
3498 if (TREE_CODE (stmt) == BLOCK)
3500 tree parent = BLOCK_SUPERCONTEXT (stmt);
3502 if (parent && TREE_CODE (parent) == BLOCK)
3504 tree grandparent = BLOCK_SUPERCONTEXT (parent);
3506 if (grandparent && TREE_CODE (grandparent) == FUNCTION_DECL)
3507 return 1;
3511 return 0;
3514 /* True if we are currently emitting insns in an area of output code
3515 that is controlled by a conditional expression. This is used by
3516 the cleanup handling code to generate conditional cleanup actions. */
3519 conditional_context ()
3521 return block_stack && block_stack->data.block.conditional_code;
3524 /* Return an opaque pointer to the current nesting level, so frontend code
3525 can check its own sanity. */
3527 struct nesting *
3528 current_nesting_level ()
3530 return cfun ? block_stack : 0;
3533 /* Emit a handler label for a nonlocal goto handler.
3534 Also emit code to store the handler label in SLOT before BEFORE_INSN. */
3536 static rtx
3537 expand_nl_handler_label (slot, before_insn)
3538 rtx slot, before_insn;
3540 rtx insns;
3541 rtx handler_label = gen_label_rtx ();
3543 /* Don't let cleanup_cfg delete the handler. */
3544 LABEL_PRESERVE_P (handler_label) = 1;
3546 start_sequence ();
3547 emit_move_insn (slot, gen_rtx_LABEL_REF (Pmode, handler_label));
3548 insns = get_insns ();
3549 end_sequence ();
3550 emit_insn_before (insns, before_insn);
3552 emit_label (handler_label);
3554 return handler_label;
3557 /* Emit code to restore vital registers at the beginning of a nonlocal goto
3558 handler. */
3559 static void
3560 expand_nl_goto_receiver ()
3562 #ifdef HAVE_nonlocal_goto
3563 if (! HAVE_nonlocal_goto)
3564 #endif
3565 /* First adjust our frame pointer to its actual value. It was
3566 previously set to the start of the virtual area corresponding to
3567 the stacked variables when we branched here and now needs to be
3568 adjusted to the actual hardware fp value.
3570 Assignments are to virtual registers are converted by
3571 instantiate_virtual_regs into the corresponding assignment
3572 to the underlying register (fp in this case) that makes
3573 the original assignment true.
3574 So the following insn will actually be
3575 decrementing fp by STARTING_FRAME_OFFSET. */
3576 emit_move_insn (virtual_stack_vars_rtx, hard_frame_pointer_rtx);
3578 #if ARG_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3579 if (fixed_regs[ARG_POINTER_REGNUM])
3581 #ifdef ELIMINABLE_REGS
3582 /* If the argument pointer can be eliminated in favor of the
3583 frame pointer, we don't need to restore it. We assume here
3584 that if such an elimination is present, it can always be used.
3585 This is the case on all known machines; if we don't make this
3586 assumption, we do unnecessary saving on many machines. */
3587 static const struct elims {const int from, to;} elim_regs[] = ELIMINABLE_REGS;
3588 size_t i;
3590 for (i = 0; i < ARRAY_SIZE (elim_regs); i++)
3591 if (elim_regs[i].from == ARG_POINTER_REGNUM
3592 && elim_regs[i].to == HARD_FRAME_POINTER_REGNUM)
3593 break;
3595 if (i == ARRAY_SIZE (elim_regs))
3596 #endif
3598 /* Now restore our arg pointer from the address at which it
3599 was saved in our stack frame. */
3600 emit_move_insn (virtual_incoming_args_rtx,
3601 copy_to_reg (get_arg_pointer_save_area (cfun)));
3604 #endif
3606 #ifdef HAVE_nonlocal_goto_receiver
3607 if (HAVE_nonlocal_goto_receiver)
3608 emit_insn (gen_nonlocal_goto_receiver ());
3609 #endif
3612 /* Make handlers for nonlocal gotos taking place in the function calls in
3613 block THISBLOCK. */
3615 static void
3616 expand_nl_goto_receivers (thisblock)
3617 struct nesting *thisblock;
3619 tree link;
3620 rtx afterward = gen_label_rtx ();
3621 rtx insns, slot;
3622 rtx label_list;
3623 int any_invalid;
3625 /* Record the handler address in the stack slot for that purpose,
3626 during this block, saving and restoring the outer value. */
3627 if (thisblock->next != 0)
3628 for (slot = nonlocal_goto_handler_slots; slot; slot = XEXP (slot, 1))
3630 rtx save_receiver = gen_reg_rtx (Pmode);
3631 emit_move_insn (XEXP (slot, 0), save_receiver);
3633 start_sequence ();
3634 emit_move_insn (save_receiver, XEXP (slot, 0));
3635 insns = get_insns ();
3636 end_sequence ();
3637 emit_insn_before (insns, thisblock->data.block.first_insn);
3640 /* Jump around the handlers; they run only when specially invoked. */
3641 emit_jump (afterward);
3643 /* Make a separate handler for each label. */
3644 link = nonlocal_labels;
3645 slot = nonlocal_goto_handler_slots;
3646 label_list = NULL_RTX;
3647 for (; link; link = TREE_CHAIN (link), slot = XEXP (slot, 1))
3648 /* Skip any labels we shouldn't be able to jump to from here,
3649 we generate one special handler for all of them below which just calls
3650 abort. */
3651 if (! DECL_TOO_LATE (TREE_VALUE (link)))
3653 rtx lab;
3654 lab = expand_nl_handler_label (XEXP (slot, 0),
3655 thisblock->data.block.first_insn);
3656 label_list = gen_rtx_EXPR_LIST (VOIDmode, lab, label_list);
3658 expand_nl_goto_receiver ();
3660 /* Jump to the "real" nonlocal label. */
3661 expand_goto (TREE_VALUE (link));
3664 /* A second pass over all nonlocal labels; this time we handle those
3665 we should not be able to jump to at this point. */
3666 link = nonlocal_labels;
3667 slot = nonlocal_goto_handler_slots;
3668 any_invalid = 0;
3669 for (; link; link = TREE_CHAIN (link), slot = XEXP (slot, 1))
3670 if (DECL_TOO_LATE (TREE_VALUE (link)))
3672 rtx lab;
3673 lab = expand_nl_handler_label (XEXP (slot, 0),
3674 thisblock->data.block.first_insn);
3675 label_list = gen_rtx_EXPR_LIST (VOIDmode, lab, label_list);
3676 any_invalid = 1;
3679 if (any_invalid)
3681 expand_nl_goto_receiver ();
3682 expand_builtin_trap ();
3685 nonlocal_goto_handler_labels = label_list;
3686 emit_label (afterward);
3689 /* Warn about any unused VARS (which may contain nodes other than
3690 VAR_DECLs, but such nodes are ignored). The nodes are connected
3691 via the TREE_CHAIN field. */
3693 void
3694 warn_about_unused_variables (vars)
3695 tree vars;
3697 tree decl;
3699 if (warn_unused_variable)
3700 for (decl = vars; decl; decl = TREE_CHAIN (decl))
3701 if (TREE_CODE (decl) == VAR_DECL
3702 && ! TREE_USED (decl)
3703 && ! DECL_IN_SYSTEM_HEADER (decl)
3704 && DECL_NAME (decl) && ! DECL_ARTIFICIAL (decl))
3705 warning_with_decl (decl, "unused variable `%s'");
3708 /* Generate RTL code to terminate a binding contour.
3710 VARS is the chain of VAR_DECL nodes for the variables bound in this
3711 contour. There may actually be other nodes in this chain, but any
3712 nodes other than VAR_DECLS are ignored.
3714 MARK_ENDS is nonzero if we should put a note at the beginning
3715 and end of this binding contour.
3717 DONT_JUMP_IN is nonzero if it is not valid to jump into this contour.
3718 (That is true automatically if the contour has a saved stack level.) */
3720 void
3721 expand_end_bindings (vars, mark_ends, dont_jump_in)
3722 tree vars;
3723 int mark_ends;
3724 int dont_jump_in;
3726 struct nesting *thisblock = block_stack;
3728 /* If any of the variables in this scope were not used, warn the
3729 user. */
3730 warn_about_unused_variables (vars);
3732 if (thisblock->exit_label)
3734 do_pending_stack_adjust ();
3735 emit_label (thisblock->exit_label);
3738 /* If necessary, make handlers for nonlocal gotos taking
3739 place in the function calls in this block. */
3740 if (function_call_count != thisblock->data.block.n_function_calls
3741 && nonlocal_labels
3742 /* Make handler for outermost block
3743 if there were any nonlocal gotos to this function. */
3744 && (thisblock->next == 0 ? current_function_has_nonlocal_label
3745 /* Make handler for inner block if it has something
3746 special to do when you jump out of it. */
3747 : (thisblock->data.block.cleanups != 0
3748 || thisblock->data.block.stack_level != 0)))
3749 expand_nl_goto_receivers (thisblock);
3751 /* Don't allow jumping into a block that has a stack level.
3752 Cleanups are allowed, though. */
3753 if (dont_jump_in
3754 || thisblock->data.block.stack_level != 0)
3756 struct label_chain *chain;
3758 /* Any labels in this block are no longer valid to go to.
3759 Mark them to cause an error message. */
3760 for (chain = thisblock->data.block.label_chain; chain; chain = chain->next)
3762 DECL_TOO_LATE (chain->label) = 1;
3763 /* If any goto without a fixup came to this label,
3764 that must be an error, because gotos without fixups
3765 come from outside all saved stack-levels. */
3766 if (TREE_ADDRESSABLE (chain->label))
3767 error_with_decl (chain->label,
3768 "label `%s' used before containing binding contour");
3772 /* Restore stack level in effect before the block
3773 (only if variable-size objects allocated). */
3774 /* Perform any cleanups associated with the block. */
3776 if (thisblock->data.block.stack_level != 0
3777 || thisblock->data.block.cleanups != 0)
3779 int reachable;
3780 rtx insn;
3782 /* Don't let cleanups affect ({...}) constructs. */
3783 int old_expr_stmts_for_value = expr_stmts_for_value;
3784 rtx old_last_expr_value = last_expr_value;
3785 tree old_last_expr_type = last_expr_type;
3786 expr_stmts_for_value = 0;
3788 /* Only clean up here if this point can actually be reached. */
3789 insn = get_last_insn ();
3790 if (GET_CODE (insn) == NOTE)
3791 insn = prev_nonnote_insn (insn);
3792 reachable = (! insn || GET_CODE (insn) != BARRIER);
3794 /* Do the cleanups. */
3795 expand_cleanups (thisblock->data.block.cleanups, NULL_TREE, 0, reachable);
3796 if (reachable)
3797 do_pending_stack_adjust ();
3799 expr_stmts_for_value = old_expr_stmts_for_value;
3800 last_expr_value = old_last_expr_value;
3801 last_expr_type = old_last_expr_type;
3803 /* Restore the stack level. */
3805 if (reachable && thisblock->data.block.stack_level != 0)
3807 emit_stack_restore (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3808 thisblock->data.block.stack_level, NULL_RTX);
3809 if (nonlocal_goto_handler_slots != 0)
3810 emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level,
3811 NULL_RTX);
3814 /* Any gotos out of this block must also do these things.
3815 Also report any gotos with fixups that came to labels in this
3816 level. */
3817 fixup_gotos (thisblock,
3818 thisblock->data.block.stack_level,
3819 thisblock->data.block.cleanups,
3820 thisblock->data.block.first_insn,
3821 dont_jump_in);
3824 /* Mark the beginning and end of the scope if requested.
3825 We do this now, after running cleanups on the variables
3826 just going out of scope, so they are in scope for their cleanups. */
3828 if (mark_ends)
3830 rtx note = emit_note (NULL, NOTE_INSN_BLOCK_END);
3831 NOTE_BLOCK (note) = NOTE_BLOCK (thisblock->data.block.first_insn);
3833 else
3834 /* Get rid of the beginning-mark if we don't make an end-mark. */
3835 NOTE_LINE_NUMBER (thisblock->data.block.first_insn) = NOTE_INSN_DELETED;
3837 /* Restore the temporary level of TARGET_EXPRs. */
3838 target_temp_slot_level = thisblock->data.block.block_target_temp_slot_level;
3840 /* Restore block_stack level for containing block. */
3842 stack_block_stack = thisblock->data.block.innermost_stack_block;
3843 POPSTACK (block_stack);
3845 /* Pop the stack slot nesting and free any slots at this level. */
3846 pop_temp_slots ();
3849 /* Generate code to save the stack pointer at the start of the current block
3850 and set up to restore it on exit. */
3852 void
3853 save_stack_pointer ()
3855 struct nesting *thisblock = block_stack;
3857 if (thisblock->data.block.stack_level == 0)
3859 emit_stack_save (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3860 &thisblock->data.block.stack_level,
3861 thisblock->data.block.first_insn);
3862 stack_block_stack = thisblock;
3866 /* Generate RTL for the automatic variable declaration DECL.
3867 (Other kinds of declarations are simply ignored if seen here.) */
3869 void
3870 expand_decl (decl)
3871 tree decl;
3873 tree type;
3875 type = TREE_TYPE (decl);
3877 /* For a CONST_DECL, set mode, alignment, and sizes from those of the
3878 type in case this node is used in a reference. */
3879 if (TREE_CODE (decl) == CONST_DECL)
3881 DECL_MODE (decl) = TYPE_MODE (type);
3882 DECL_ALIGN (decl) = TYPE_ALIGN (type);
3883 DECL_SIZE (decl) = TYPE_SIZE (type);
3884 DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (type);
3885 return;
3888 /* Otherwise, only automatic variables need any expansion done. Static and
3889 external variables, and external functions, will be handled by
3890 `assemble_variable' (called from finish_decl). TYPE_DECL requires
3891 nothing. PARM_DECLs are handled in `assign_parms'. */
3892 if (TREE_CODE (decl) != VAR_DECL)
3893 return;
3895 if (TREE_STATIC (decl) || DECL_EXTERNAL (decl))
3896 return;
3898 /* Create the RTL representation for the variable. */
3900 if (type == error_mark_node)
3901 SET_DECL_RTL (decl, gen_rtx_MEM (BLKmode, const0_rtx));
3903 else if (DECL_SIZE (decl) == 0)
3904 /* Variable with incomplete type. */
3906 rtx x;
3907 if (DECL_INITIAL (decl) == 0)
3908 /* Error message was already done; now avoid a crash. */
3909 x = gen_rtx_MEM (BLKmode, const0_rtx);
3910 else
3911 /* An initializer is going to decide the size of this array.
3912 Until we know the size, represent its address with a reg. */
3913 x = gen_rtx_MEM (BLKmode, gen_reg_rtx (Pmode));
3915 set_mem_attributes (x, decl, 1);
3916 SET_DECL_RTL (decl, x);
3918 else if (DECL_MODE (decl) != BLKmode
3919 /* If -ffloat-store, don't put explicit float vars
3920 into regs. */
3921 && !(flag_float_store
3922 && TREE_CODE (type) == REAL_TYPE)
3923 && ! TREE_THIS_VOLATILE (decl)
3924 && (DECL_REGISTER (decl) || optimize))
3926 /* Automatic variable that can go in a register. */
3927 int unsignedp = TREE_UNSIGNED (type);
3928 enum machine_mode reg_mode
3929 = promote_mode (type, DECL_MODE (decl), &unsignedp, 0);
3931 SET_DECL_RTL (decl, gen_reg_rtx (reg_mode));
3933 mark_user_reg (DECL_RTL (decl));
3935 if (POINTER_TYPE_P (type))
3936 mark_reg_pointer (DECL_RTL (decl),
3937 TYPE_ALIGN (TREE_TYPE (TREE_TYPE (decl))));
3939 maybe_set_unchanging (DECL_RTL (decl), decl);
3941 /* If something wants our address, try to use ADDRESSOF. */
3942 if (TREE_ADDRESSABLE (decl))
3943 put_var_into_stack (decl);
3946 else if (TREE_CODE (DECL_SIZE_UNIT (decl)) == INTEGER_CST
3947 && ! (flag_stack_check && ! STACK_CHECK_BUILTIN
3948 && 0 < compare_tree_int (DECL_SIZE_UNIT (decl),
3949 STACK_CHECK_MAX_VAR_SIZE)))
3951 /* Variable of fixed size that goes on the stack. */
3952 rtx oldaddr = 0;
3953 rtx addr;
3954 rtx x;
3956 /* If we previously made RTL for this decl, it must be an array
3957 whose size was determined by the initializer.
3958 The old address was a register; set that register now
3959 to the proper address. */
3960 if (DECL_RTL_SET_P (decl))
3962 if (GET_CODE (DECL_RTL (decl)) != MEM
3963 || GET_CODE (XEXP (DECL_RTL (decl), 0)) != REG)
3964 abort ();
3965 oldaddr = XEXP (DECL_RTL (decl), 0);
3968 /* Set alignment we actually gave this decl. */
3969 DECL_ALIGN (decl) = (DECL_MODE (decl) == BLKmode ? BIGGEST_ALIGNMENT
3970 : GET_MODE_BITSIZE (DECL_MODE (decl)));
3971 DECL_USER_ALIGN (decl) = 0;
3973 x = assign_temp (decl, 1, 1, 1);
3974 set_mem_attributes (x, decl, 1);
3975 SET_DECL_RTL (decl, x);
3977 if (oldaddr)
3979 addr = force_operand (XEXP (DECL_RTL (decl), 0), oldaddr);
3980 if (addr != oldaddr)
3981 emit_move_insn (oldaddr, addr);
3984 else
3985 /* Dynamic-size object: must push space on the stack. */
3987 rtx address, size, x;
3989 /* Record the stack pointer on entry to block, if have
3990 not already done so. */
3991 do_pending_stack_adjust ();
3992 save_stack_pointer ();
3994 /* In function-at-a-time mode, variable_size doesn't expand this,
3995 so do it now. */
3996 if (TREE_CODE (type) == ARRAY_TYPE && TYPE_DOMAIN (type))
3997 expand_expr (TYPE_MAX_VALUE (TYPE_DOMAIN (type)),
3998 const0_rtx, VOIDmode, 0);
4000 /* Compute the variable's size, in bytes. */
4001 size = expand_expr (DECL_SIZE_UNIT (decl), NULL_RTX, VOIDmode, 0);
4002 free_temp_slots ();
4004 /* Allocate space on the stack for the variable. Note that
4005 DECL_ALIGN says how the variable is to be aligned and we
4006 cannot use it to conclude anything about the alignment of
4007 the size. */
4008 address = allocate_dynamic_stack_space (size, NULL_RTX,
4009 TYPE_ALIGN (TREE_TYPE (decl)));
4011 /* Reference the variable indirect through that rtx. */
4012 x = gen_rtx_MEM (DECL_MODE (decl), address);
4013 set_mem_attributes (x, decl, 1);
4014 SET_DECL_RTL (decl, x);
4017 /* Indicate the alignment we actually gave this variable. */
4018 #ifdef STACK_BOUNDARY
4019 DECL_ALIGN (decl) = STACK_BOUNDARY;
4020 #else
4021 DECL_ALIGN (decl) = BIGGEST_ALIGNMENT;
4022 #endif
4023 DECL_USER_ALIGN (decl) = 0;
4027 /* Emit code to perform the initialization of a declaration DECL. */
4029 void
4030 expand_decl_init (decl)
4031 tree decl;
4033 int was_used = TREE_USED (decl);
4035 /* If this is a CONST_DECL, we don't have to generate any code. Likewise
4036 for static decls. */
4037 if (TREE_CODE (decl) == CONST_DECL
4038 || TREE_STATIC (decl))
4039 return;
4041 /* Compute and store the initial value now. */
4043 if (DECL_INITIAL (decl) == error_mark_node)
4045 enum tree_code code = TREE_CODE (TREE_TYPE (decl));
4047 if (code == INTEGER_TYPE || code == REAL_TYPE || code == ENUMERAL_TYPE
4048 || code == POINTER_TYPE || code == REFERENCE_TYPE)
4049 expand_assignment (decl, convert (TREE_TYPE (decl), integer_zero_node),
4050 0, 0);
4051 emit_queue ();
4053 else if (DECL_INITIAL (decl) && TREE_CODE (DECL_INITIAL (decl)) != TREE_LIST)
4055 emit_line_note (DECL_SOURCE_FILE (decl), DECL_SOURCE_LINE (decl));
4056 expand_assignment (decl, DECL_INITIAL (decl), 0, 0);
4057 emit_queue ();
4060 /* Don't let the initialization count as "using" the variable. */
4061 TREE_USED (decl) = was_used;
4063 /* Free any temporaries we made while initializing the decl. */
4064 preserve_temp_slots (NULL_RTX);
4065 free_temp_slots ();
4068 /* CLEANUP is an expression to be executed at exit from this binding contour;
4069 for example, in C++, it might call the destructor for this variable.
4071 We wrap CLEANUP in an UNSAVE_EXPR node, so that we can expand the
4072 CLEANUP multiple times, and have the correct semantics. This
4073 happens in exception handling, for gotos, returns, breaks that
4074 leave the current scope.
4076 If CLEANUP is nonzero and DECL is zero, we record a cleanup
4077 that is not associated with any particular variable. */
4080 expand_decl_cleanup (decl, cleanup)
4081 tree decl, cleanup;
4083 struct nesting *thisblock;
4085 /* Error if we are not in any block. */
4086 if (cfun == 0 || block_stack == 0)
4087 return 0;
4089 thisblock = block_stack;
4091 /* Record the cleanup if there is one. */
4093 if (cleanup != 0)
4095 tree t;
4096 rtx seq;
4097 tree *cleanups = &thisblock->data.block.cleanups;
4098 int cond_context = conditional_context ();
4100 if (cond_context)
4102 rtx flag = gen_reg_rtx (word_mode);
4103 rtx set_flag_0;
4104 tree cond;
4106 start_sequence ();
4107 emit_move_insn (flag, const0_rtx);
4108 set_flag_0 = get_insns ();
4109 end_sequence ();
4111 thisblock->data.block.last_unconditional_cleanup
4112 = emit_insn_after (set_flag_0,
4113 thisblock->data.block.last_unconditional_cleanup);
4115 emit_move_insn (flag, const1_rtx);
4117 cond = build_decl (VAR_DECL, NULL_TREE,
4118 (*lang_hooks.types.type_for_mode) (word_mode, 1));
4119 SET_DECL_RTL (cond, flag);
4121 /* Conditionalize the cleanup. */
4122 cleanup = build (COND_EXPR, void_type_node,
4123 (*lang_hooks.truthvalue_conversion) (cond),
4124 cleanup, integer_zero_node);
4125 cleanup = fold (cleanup);
4127 cleanups = &thisblock->data.block.cleanups;
4130 cleanup = unsave_expr (cleanup);
4132 t = *cleanups = tree_cons (decl, cleanup, *cleanups);
4134 if (! cond_context)
4135 /* If this block has a cleanup, it belongs in stack_block_stack. */
4136 stack_block_stack = thisblock;
4138 if (cond_context)
4140 start_sequence ();
4143 if (! using_eh_for_cleanups_p)
4144 TREE_ADDRESSABLE (t) = 1;
4145 else
4146 expand_eh_region_start ();
4148 if (cond_context)
4150 seq = get_insns ();
4151 end_sequence ();
4152 if (seq)
4153 thisblock->data.block.last_unconditional_cleanup
4154 = emit_insn_after (seq,
4155 thisblock->data.block.last_unconditional_cleanup);
4157 else
4159 thisblock->data.block.last_unconditional_cleanup
4160 = get_last_insn ();
4161 /* When we insert instructions after the last unconditional cleanup,
4162 we don't adjust last_insn. That means that a later add_insn will
4163 clobber the instructions we've just added. The easiest way to
4164 fix this is to just insert another instruction here, so that the
4165 instructions inserted after the last unconditional cleanup are
4166 never the last instruction. */
4167 emit_note (NULL, NOTE_INSN_DELETED);
4170 return 1;
4173 /* Like expand_decl_cleanup, but maybe only run the cleanup if an exception
4174 is thrown. */
4177 expand_decl_cleanup_eh (decl, cleanup, eh_only)
4178 tree decl, cleanup;
4179 int eh_only;
4181 int ret = expand_decl_cleanup (decl, cleanup);
4182 if (cleanup && ret)
4184 tree node = block_stack->data.block.cleanups;
4185 CLEANUP_EH_ONLY (node) = eh_only;
4187 return ret;
4190 /* DECL is an anonymous union. CLEANUP is a cleanup for DECL.
4191 DECL_ELTS is the list of elements that belong to DECL's type.
4192 In each, the TREE_VALUE is a VAR_DECL, and the TREE_PURPOSE a cleanup. */
4194 void
4195 expand_anon_union_decl (decl, cleanup, decl_elts)
4196 tree decl, cleanup, decl_elts;
4198 struct nesting *thisblock = cfun == 0 ? 0 : block_stack;
4199 rtx x;
4200 tree t;
4202 /* If any of the elements are addressable, so is the entire union. */
4203 for (t = decl_elts; t; t = TREE_CHAIN (t))
4204 if (TREE_ADDRESSABLE (TREE_VALUE (t)))
4206 TREE_ADDRESSABLE (decl) = 1;
4207 break;
4210 expand_decl (decl);
4211 expand_decl_cleanup (decl, cleanup);
4212 x = DECL_RTL (decl);
4214 /* Go through the elements, assigning RTL to each. */
4215 for (t = decl_elts; t; t = TREE_CHAIN (t))
4217 tree decl_elt = TREE_VALUE (t);
4218 tree cleanup_elt = TREE_PURPOSE (t);
4219 enum machine_mode mode = TYPE_MODE (TREE_TYPE (decl_elt));
4221 /* If any of the elements are addressable, so is the entire
4222 union. */
4223 if (TREE_USED (decl_elt))
4224 TREE_USED (decl) = 1;
4226 /* Propagate the union's alignment to the elements. */
4227 DECL_ALIGN (decl_elt) = DECL_ALIGN (decl);
4228 DECL_USER_ALIGN (decl_elt) = DECL_USER_ALIGN (decl);
4230 /* If the element has BLKmode and the union doesn't, the union is
4231 aligned such that the element doesn't need to have BLKmode, so
4232 change the element's mode to the appropriate one for its size. */
4233 if (mode == BLKmode && DECL_MODE (decl) != BLKmode)
4234 DECL_MODE (decl_elt) = mode
4235 = mode_for_size_tree (DECL_SIZE (decl_elt), MODE_INT, 1);
4237 /* (SUBREG (MEM ...)) at RTL generation time is invalid, so we
4238 instead create a new MEM rtx with the proper mode. */
4239 if (GET_CODE (x) == MEM)
4241 if (mode == GET_MODE (x))
4242 SET_DECL_RTL (decl_elt, x);
4243 else
4244 SET_DECL_RTL (decl_elt, adjust_address_nv (x, mode, 0));
4246 else if (GET_CODE (x) == REG)
4248 if (mode == GET_MODE (x))
4249 SET_DECL_RTL (decl_elt, x);
4250 else
4251 SET_DECL_RTL (decl_elt, gen_lowpart_SUBREG (mode, x));
4253 else
4254 abort ();
4256 /* Record the cleanup if there is one. */
4258 if (cleanup != 0)
4259 thisblock->data.block.cleanups
4260 = tree_cons (decl_elt, cleanup_elt,
4261 thisblock->data.block.cleanups);
4265 /* Expand a list of cleanups LIST.
4266 Elements may be expressions or may be nested lists.
4268 If DONT_DO is nonnull, then any list-element
4269 whose TREE_PURPOSE matches DONT_DO is omitted.
4270 This is sometimes used to avoid a cleanup associated with
4271 a value that is being returned out of the scope.
4273 If IN_FIXUP is nonzero, we are generating this cleanup for a fixup
4274 goto and handle protection regions specially in that case.
4276 If REACHABLE, we emit code, otherwise just inform the exception handling
4277 code about this finalization. */
4279 static void
4280 expand_cleanups (list, dont_do, in_fixup, reachable)
4281 tree list;
4282 tree dont_do;
4283 int in_fixup;
4284 int reachable;
4286 tree tail;
4287 for (tail = list; tail; tail = TREE_CHAIN (tail))
4288 if (dont_do == 0 || TREE_PURPOSE (tail) != dont_do)
4290 if (TREE_CODE (TREE_VALUE (tail)) == TREE_LIST)
4291 expand_cleanups (TREE_VALUE (tail), dont_do, in_fixup, reachable);
4292 else
4294 if (! in_fixup && using_eh_for_cleanups_p)
4295 expand_eh_region_end_cleanup (TREE_VALUE (tail));
4297 if (reachable && !CLEANUP_EH_ONLY (tail))
4299 /* Cleanups may be run multiple times. For example,
4300 when exiting a binding contour, we expand the
4301 cleanups associated with that contour. When a goto
4302 within that binding contour has a target outside that
4303 contour, it will expand all cleanups from its scope to
4304 the target. Though the cleanups are expanded multiple
4305 times, the control paths are non-overlapping so the
4306 cleanups will not be executed twice. */
4308 /* We may need to protect from outer cleanups. */
4309 if (in_fixup && using_eh_for_cleanups_p)
4311 expand_eh_region_start ();
4313 expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0);
4315 expand_eh_region_end_fixup (TREE_VALUE (tail));
4317 else
4318 expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0);
4320 free_temp_slots ();
4326 /* Mark when the context we are emitting RTL for as a conditional
4327 context, so that any cleanup actions we register with
4328 expand_decl_init will be properly conditionalized when those
4329 cleanup actions are later performed. Must be called before any
4330 expression (tree) is expanded that is within a conditional context. */
4332 void
4333 start_cleanup_deferral ()
4335 /* block_stack can be NULL if we are inside the parameter list. It is
4336 OK to do nothing, because cleanups aren't possible here. */
4337 if (block_stack)
4338 ++block_stack->data.block.conditional_code;
4341 /* Mark the end of a conditional region of code. Because cleanup
4342 deferrals may be nested, we may still be in a conditional region
4343 after we end the currently deferred cleanups, only after we end all
4344 deferred cleanups, are we back in unconditional code. */
4346 void
4347 end_cleanup_deferral ()
4349 /* block_stack can be NULL if we are inside the parameter list. It is
4350 OK to do nothing, because cleanups aren't possible here. */
4351 if (block_stack)
4352 --block_stack->data.block.conditional_code;
4355 tree
4356 last_cleanup_this_contour ()
4358 if (block_stack == 0)
4359 return 0;
4361 return block_stack->data.block.cleanups;
4364 /* Return 1 if there are any pending cleanups at this point.
4365 If THIS_CONTOUR is nonzero, check the current contour as well.
4366 Otherwise, look only at the contours that enclose this one. */
4369 any_pending_cleanups (this_contour)
4370 int this_contour;
4372 struct nesting *block;
4374 if (cfun == NULL || cfun->stmt == NULL || block_stack == 0)
4375 return 0;
4377 if (this_contour && block_stack->data.block.cleanups != NULL)
4378 return 1;
4379 if (block_stack->data.block.cleanups == 0
4380 && block_stack->data.block.outer_cleanups == 0)
4381 return 0;
4383 for (block = block_stack->next; block; block = block->next)
4384 if (block->data.block.cleanups != 0)
4385 return 1;
4387 return 0;
4390 /* Enter a case (Pascal) or switch (C) statement.
4391 Push a block onto case_stack and nesting_stack
4392 to accumulate the case-labels that are seen
4393 and to record the labels generated for the statement.
4395 EXIT_FLAG is nonzero if `exit_something' should exit this case stmt.
4396 Otherwise, this construct is transparent for `exit_something'.
4398 EXPR is the index-expression to be dispatched on.
4399 TYPE is its nominal type. We could simply convert EXPR to this type,
4400 but instead we take short cuts. */
4402 void
4403 expand_start_case (exit_flag, expr, type, printname)
4404 int exit_flag;
4405 tree expr;
4406 tree type;
4407 const char *printname;
4409 struct nesting *thiscase = ALLOC_NESTING ();
4411 /* Make an entry on case_stack for the case we are entering. */
4413 thiscase->desc = CASE_NESTING;
4414 thiscase->next = case_stack;
4415 thiscase->all = nesting_stack;
4416 thiscase->depth = ++nesting_depth;
4417 thiscase->exit_label = exit_flag ? gen_label_rtx () : 0;
4418 thiscase->data.case_stmt.case_list = 0;
4419 thiscase->data.case_stmt.index_expr = expr;
4420 thiscase->data.case_stmt.nominal_type = type;
4421 thiscase->data.case_stmt.default_label = 0;
4422 thiscase->data.case_stmt.printname = printname;
4423 thiscase->data.case_stmt.line_number_status = force_line_numbers ();
4424 case_stack = thiscase;
4425 nesting_stack = thiscase;
4427 do_pending_stack_adjust ();
4429 /* Make sure case_stmt.start points to something that won't
4430 need any transformation before expand_end_case. */
4431 if (GET_CODE (get_last_insn ()) != NOTE)
4432 emit_note (NULL, NOTE_INSN_DELETED);
4434 thiscase->data.case_stmt.start = get_last_insn ();
4436 start_cleanup_deferral ();
4439 /* Start a "dummy case statement" within which case labels are invalid
4440 and are not connected to any larger real case statement.
4441 This can be used if you don't want to let a case statement jump
4442 into the middle of certain kinds of constructs. */
4444 void
4445 expand_start_case_dummy ()
4447 struct nesting *thiscase = ALLOC_NESTING ();
4449 /* Make an entry on case_stack for the dummy. */
4451 thiscase->desc = CASE_NESTING;
4452 thiscase->next = case_stack;
4453 thiscase->all = nesting_stack;
4454 thiscase->depth = ++nesting_depth;
4455 thiscase->exit_label = 0;
4456 thiscase->data.case_stmt.case_list = 0;
4457 thiscase->data.case_stmt.start = 0;
4458 thiscase->data.case_stmt.nominal_type = 0;
4459 thiscase->data.case_stmt.default_label = 0;
4460 case_stack = thiscase;
4461 nesting_stack = thiscase;
4462 start_cleanup_deferral ();
4465 static void
4466 check_seenlabel ()
4468 /* If this is the first label, warn if any insns have been emitted. */
4469 if (case_stack->data.case_stmt.line_number_status >= 0)
4471 rtx insn;
4473 restore_line_number_status
4474 (case_stack->data.case_stmt.line_number_status);
4475 case_stack->data.case_stmt.line_number_status = -1;
4477 for (insn = case_stack->data.case_stmt.start;
4478 insn;
4479 insn = NEXT_INSN (insn))
4481 if (GET_CODE (insn) == CODE_LABEL)
4482 break;
4483 if (GET_CODE (insn) != NOTE
4484 && (GET_CODE (insn) != INSN || GET_CODE (PATTERN (insn)) != USE))
4487 insn = PREV_INSN (insn);
4488 while (insn && (GET_CODE (insn) != NOTE || NOTE_LINE_NUMBER (insn) < 0));
4490 /* If insn is zero, then there must have been a syntax error. */
4491 if (insn)
4492 warning_with_file_and_line (NOTE_SOURCE_FILE (insn),
4493 NOTE_LINE_NUMBER (insn),
4494 "unreachable code at beginning of %s",
4495 case_stack->data.case_stmt.printname);
4496 break;
4502 /* Accumulate one case or default label inside a case or switch statement.
4503 VALUE is the value of the case (a null pointer, for a default label).
4504 The function CONVERTER, when applied to arguments T and V,
4505 converts the value V to the type T.
4507 If not currently inside a case or switch statement, return 1 and do
4508 nothing. The caller will print a language-specific error message.
4509 If VALUE is a duplicate or overlaps, return 2 and do nothing
4510 except store the (first) duplicate node in *DUPLICATE.
4511 If VALUE is out of range, return 3 and do nothing.
4512 If we are jumping into the scope of a cleanup or var-sized array, return 5.
4513 Return 0 on success.
4515 Extended to handle range statements. */
4518 pushcase (value, converter, label, duplicate)
4519 tree value;
4520 tree (*converter) PARAMS ((tree, tree));
4521 tree label;
4522 tree *duplicate;
4524 tree index_type;
4525 tree nominal_type;
4527 /* Fail if not inside a real case statement. */
4528 if (! (case_stack && case_stack->data.case_stmt.start))
4529 return 1;
4531 if (stack_block_stack
4532 && stack_block_stack->depth > case_stack->depth)
4533 return 5;
4535 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
4536 nominal_type = case_stack->data.case_stmt.nominal_type;
4538 /* If the index is erroneous, avoid more problems: pretend to succeed. */
4539 if (index_type == error_mark_node)
4540 return 0;
4542 /* Convert VALUE to the type in which the comparisons are nominally done. */
4543 if (value != 0)
4544 value = (*converter) (nominal_type, value);
4546 check_seenlabel ();
4548 /* Fail if this value is out of range for the actual type of the index
4549 (which may be narrower than NOMINAL_TYPE). */
4550 if (value != 0
4551 && (TREE_CONSTANT_OVERFLOW (value)
4552 || ! int_fits_type_p (value, index_type)))
4553 return 3;
4555 return add_case_node (value, value, label, duplicate);
4558 /* Like pushcase but this case applies to all values between VALUE1 and
4559 VALUE2 (inclusive). If VALUE1 is NULL, the range starts at the lowest
4560 value of the index type and ends at VALUE2. If VALUE2 is NULL, the range
4561 starts at VALUE1 and ends at the highest value of the index type.
4562 If both are NULL, this case applies to all values.
4564 The return value is the same as that of pushcase but there is one
4565 additional error code: 4 means the specified range was empty. */
4568 pushcase_range (value1, value2, converter, label, duplicate)
4569 tree value1, value2;
4570 tree (*converter) PARAMS ((tree, tree));
4571 tree label;
4572 tree *duplicate;
4574 tree index_type;
4575 tree nominal_type;
4577 /* Fail if not inside a real case statement. */
4578 if (! (case_stack && case_stack->data.case_stmt.start))
4579 return 1;
4581 if (stack_block_stack
4582 && stack_block_stack->depth > case_stack->depth)
4583 return 5;
4585 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
4586 nominal_type = case_stack->data.case_stmt.nominal_type;
4588 /* If the index is erroneous, avoid more problems: pretend to succeed. */
4589 if (index_type == error_mark_node)
4590 return 0;
4592 check_seenlabel ();
4594 /* Convert VALUEs to type in which the comparisons are nominally done
4595 and replace any unspecified value with the corresponding bound. */
4596 if (value1 == 0)
4597 value1 = TYPE_MIN_VALUE (index_type);
4598 if (value2 == 0)
4599 value2 = TYPE_MAX_VALUE (index_type);
4601 /* Fail if the range is empty. Do this before any conversion since
4602 we want to allow out-of-range empty ranges. */
4603 if (value2 != 0 && tree_int_cst_lt (value2, value1))
4604 return 4;
4606 /* If the max was unbounded, use the max of the nominal_type we are
4607 converting to. Do this after the < check above to suppress false
4608 positives. */
4609 if (value2 == 0)
4610 value2 = TYPE_MAX_VALUE (nominal_type);
4612 value1 = (*converter) (nominal_type, value1);
4613 value2 = (*converter) (nominal_type, value2);
4615 /* Fail if these values are out of range. */
4616 if (TREE_CONSTANT_OVERFLOW (value1)
4617 || ! int_fits_type_p (value1, index_type))
4618 return 3;
4620 if (TREE_CONSTANT_OVERFLOW (value2)
4621 || ! int_fits_type_p (value2, index_type))
4622 return 3;
4624 return add_case_node (value1, value2, label, duplicate);
4627 /* Do the actual insertion of a case label for pushcase and pushcase_range
4628 into case_stack->data.case_stmt.case_list. Use an AVL tree to avoid
4629 slowdown for large switch statements. */
4632 add_case_node (low, high, label, duplicate)
4633 tree low, high;
4634 tree label;
4635 tree *duplicate;
4637 struct case_node *p, **q, *r;
4639 /* If there's no HIGH value, then this is not a case range; it's
4640 just a simple case label. But that's just a degenerate case
4641 range. */
4642 if (!high)
4643 high = low;
4645 /* Handle default labels specially. */
4646 if (!high && !low)
4648 if (case_stack->data.case_stmt.default_label != 0)
4650 *duplicate = case_stack->data.case_stmt.default_label;
4651 return 2;
4653 case_stack->data.case_stmt.default_label = label;
4654 expand_label (label);
4655 return 0;
4658 q = &case_stack->data.case_stmt.case_list;
4659 p = *q;
4661 while ((r = *q))
4663 p = r;
4665 /* Keep going past elements distinctly greater than HIGH. */
4666 if (tree_int_cst_lt (high, p->low))
4667 q = &p->left;
4669 /* or distinctly less than LOW. */
4670 else if (tree_int_cst_lt (p->high, low))
4671 q = &p->right;
4673 else
4675 /* We have an overlap; this is an error. */
4676 *duplicate = p->code_label;
4677 return 2;
4681 /* Add this label to the chain, and succeed. */
4683 r = (struct case_node *) ggc_alloc (sizeof (struct case_node));
4684 r->low = low;
4686 /* If the bounds are equal, turn this into the one-value case. */
4687 if (tree_int_cst_equal (low, high))
4688 r->high = r->low;
4689 else
4690 r->high = high;
4692 r->code_label = label;
4693 expand_label (label);
4695 *q = r;
4696 r->parent = p;
4697 r->left = 0;
4698 r->right = 0;
4699 r->balance = 0;
4701 while (p)
4703 struct case_node *s;
4705 if (r == p->left)
4707 int b;
4709 if (! (b = p->balance))
4710 /* Growth propagation from left side. */
4711 p->balance = -1;
4712 else if (b < 0)
4714 if (r->balance < 0)
4716 /* R-Rotation */
4717 if ((p->left = s = r->right))
4718 s->parent = p;
4720 r->right = p;
4721 p->balance = 0;
4722 r->balance = 0;
4723 s = p->parent;
4724 p->parent = r;
4726 if ((r->parent = s))
4728 if (s->left == p)
4729 s->left = r;
4730 else
4731 s->right = r;
4733 else
4734 case_stack->data.case_stmt.case_list = r;
4736 else
4737 /* r->balance == +1 */
4739 /* LR-Rotation */
4741 int b2;
4742 struct case_node *t = r->right;
4744 if ((p->left = s = t->right))
4745 s->parent = p;
4747 t->right = p;
4748 if ((r->right = s = t->left))
4749 s->parent = r;
4751 t->left = r;
4752 b = t->balance;
4753 b2 = b < 0;
4754 p->balance = b2;
4755 b2 = -b2 - b;
4756 r->balance = b2;
4757 t->balance = 0;
4758 s = p->parent;
4759 p->parent = t;
4760 r->parent = t;
4762 if ((t->parent = s))
4764 if (s->left == p)
4765 s->left = t;
4766 else
4767 s->right = t;
4769 else
4770 case_stack->data.case_stmt.case_list = t;
4772 break;
4775 else
4777 /* p->balance == +1; growth of left side balances the node. */
4778 p->balance = 0;
4779 break;
4782 else
4783 /* r == p->right */
4785 int b;
4787 if (! (b = p->balance))
4788 /* Growth propagation from right side. */
4789 p->balance++;
4790 else if (b > 0)
4792 if (r->balance > 0)
4794 /* L-Rotation */
4796 if ((p->right = s = r->left))
4797 s->parent = p;
4799 r->left = p;
4800 p->balance = 0;
4801 r->balance = 0;
4802 s = p->parent;
4803 p->parent = r;
4804 if ((r->parent = s))
4806 if (s->left == p)
4807 s->left = r;
4808 else
4809 s->right = r;
4812 else
4813 case_stack->data.case_stmt.case_list = r;
4816 else
4817 /* r->balance == -1 */
4819 /* RL-Rotation */
4820 int b2;
4821 struct case_node *t = r->left;
4823 if ((p->right = s = t->left))
4824 s->parent = p;
4826 t->left = p;
4828 if ((r->left = s = t->right))
4829 s->parent = r;
4831 t->right = r;
4832 b = t->balance;
4833 b2 = b < 0;
4834 r->balance = b2;
4835 b2 = -b2 - b;
4836 p->balance = b2;
4837 t->balance = 0;
4838 s = p->parent;
4839 p->parent = t;
4840 r->parent = t;
4842 if ((t->parent = s))
4844 if (s->left == p)
4845 s->left = t;
4846 else
4847 s->right = t;
4850 else
4851 case_stack->data.case_stmt.case_list = t;
4853 break;
4855 else
4857 /* p->balance == -1; growth of right side balances the node. */
4858 p->balance = 0;
4859 break;
4863 r = p;
4864 p = p->parent;
4867 return 0;
4870 /* Returns the number of possible values of TYPE.
4871 Returns -1 if the number is unknown, variable, or if the number does not
4872 fit in a HOST_WIDE_INT.
4873 Sets *SPARSENESS to 2 if TYPE is an ENUMERAL_TYPE whose values
4874 do not increase monotonically (there may be duplicates);
4875 to 1 if the values increase monotonically, but not always by 1;
4876 otherwise sets it to 0. */
4878 HOST_WIDE_INT
4879 all_cases_count (type, sparseness)
4880 tree type;
4881 int *sparseness;
4883 tree t;
4884 HOST_WIDE_INT count, minval, lastval;
4886 *sparseness = 0;
4888 switch (TREE_CODE (type))
4890 case BOOLEAN_TYPE:
4891 count = 2;
4892 break;
4894 case CHAR_TYPE:
4895 count = 1 << BITS_PER_UNIT;
4896 break;
4898 default:
4899 case INTEGER_TYPE:
4900 if (TYPE_MAX_VALUE (type) != 0
4901 && 0 != (t = fold (build (MINUS_EXPR, type, TYPE_MAX_VALUE (type),
4902 TYPE_MIN_VALUE (type))))
4903 && 0 != (t = fold (build (PLUS_EXPR, type, t,
4904 convert (type, integer_zero_node))))
4905 && host_integerp (t, 1))
4906 count = tree_low_cst (t, 1);
4907 else
4908 return -1;
4909 break;
4911 case ENUMERAL_TYPE:
4912 /* Don't waste time with enumeral types with huge values. */
4913 if (! host_integerp (TYPE_MIN_VALUE (type), 0)
4914 || TYPE_MAX_VALUE (type) == 0
4915 || ! host_integerp (TYPE_MAX_VALUE (type), 0))
4916 return -1;
4918 lastval = minval = tree_low_cst (TYPE_MIN_VALUE (type), 0);
4919 count = 0;
4921 for (t = TYPE_VALUES (type); t != NULL_TREE; t = TREE_CHAIN (t))
4923 HOST_WIDE_INT thisval = tree_low_cst (TREE_VALUE (t), 0);
4925 if (*sparseness == 2 || thisval <= lastval)
4926 *sparseness = 2;
4927 else if (thisval != minval + count)
4928 *sparseness = 1;
4930 lastval = thisval;
4931 count++;
4935 return count;
4938 #define BITARRAY_TEST(ARRAY, INDEX) \
4939 ((ARRAY)[(unsigned) (INDEX) / HOST_BITS_PER_CHAR]\
4940 & (1 << ((unsigned) (INDEX) % HOST_BITS_PER_CHAR)))
4941 #define BITARRAY_SET(ARRAY, INDEX) \
4942 ((ARRAY)[(unsigned) (INDEX) / HOST_BITS_PER_CHAR]\
4943 |= 1 << ((unsigned) (INDEX) % HOST_BITS_PER_CHAR))
4945 /* Set the elements of the bitstring CASES_SEEN (which has length COUNT),
4946 with the case values we have seen, assuming the case expression
4947 has the given TYPE.
4948 SPARSENESS is as determined by all_cases_count.
4950 The time needed is proportional to COUNT, unless
4951 SPARSENESS is 2, in which case quadratic time is needed. */
4953 void
4954 mark_seen_cases (type, cases_seen, count, sparseness)
4955 tree type;
4956 unsigned char *cases_seen;
4957 HOST_WIDE_INT count;
4958 int sparseness;
4960 tree next_node_to_try = NULL_TREE;
4961 HOST_WIDE_INT next_node_offset = 0;
4963 struct case_node *n, *root = case_stack->data.case_stmt.case_list;
4964 tree val = make_node (INTEGER_CST);
4966 TREE_TYPE (val) = type;
4967 if (! root)
4968 /* Do nothing. */
4970 else if (sparseness == 2)
4972 tree t;
4973 unsigned HOST_WIDE_INT xlo;
4975 /* This less efficient loop is only needed to handle
4976 duplicate case values (multiple enum constants
4977 with the same value). */
4978 TREE_TYPE (val) = TREE_TYPE (root->low);
4979 for (t = TYPE_VALUES (type), xlo = 0; t != NULL_TREE;
4980 t = TREE_CHAIN (t), xlo++)
4982 TREE_INT_CST_LOW (val) = TREE_INT_CST_LOW (TREE_VALUE (t));
4983 TREE_INT_CST_HIGH (val) = TREE_INT_CST_HIGH (TREE_VALUE (t));
4984 n = root;
4987 /* Keep going past elements distinctly greater than VAL. */
4988 if (tree_int_cst_lt (val, n->low))
4989 n = n->left;
4991 /* or distinctly less than VAL. */
4992 else if (tree_int_cst_lt (n->high, val))
4993 n = n->right;
4995 else
4997 /* We have found a matching range. */
4998 BITARRAY_SET (cases_seen, xlo);
4999 break;
5002 while (n);
5005 else
5007 if (root->left)
5008 case_stack->data.case_stmt.case_list = root = case_tree2list (root, 0);
5010 for (n = root; n; n = n->right)
5012 TREE_INT_CST_LOW (val) = TREE_INT_CST_LOW (n->low);
5013 TREE_INT_CST_HIGH (val) = TREE_INT_CST_HIGH (n->low);
5014 while (! tree_int_cst_lt (n->high, val))
5016 /* Calculate (into xlo) the "offset" of the integer (val).
5017 The element with lowest value has offset 0, the next smallest
5018 element has offset 1, etc. */
5020 unsigned HOST_WIDE_INT xlo;
5021 HOST_WIDE_INT xhi;
5022 tree t;
5024 if (sparseness && TYPE_VALUES (type) != NULL_TREE)
5026 /* The TYPE_VALUES will be in increasing order, so
5027 starting searching where we last ended. */
5028 t = next_node_to_try;
5029 xlo = next_node_offset;
5030 xhi = 0;
5031 for (;;)
5033 if (t == NULL_TREE)
5035 t = TYPE_VALUES (type);
5036 xlo = 0;
5038 if (tree_int_cst_equal (val, TREE_VALUE (t)))
5040 next_node_to_try = TREE_CHAIN (t);
5041 next_node_offset = xlo + 1;
5042 break;
5044 xlo++;
5045 t = TREE_CHAIN (t);
5046 if (t == next_node_to_try)
5048 xlo = -1;
5049 break;
5053 else
5055 t = TYPE_MIN_VALUE (type);
5056 if (t)
5057 neg_double (TREE_INT_CST_LOW (t), TREE_INT_CST_HIGH (t),
5058 &xlo, &xhi);
5059 else
5060 xlo = xhi = 0;
5061 add_double (xlo, xhi,
5062 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val),
5063 &xlo, &xhi);
5066 if (xhi == 0 && xlo < (unsigned HOST_WIDE_INT) count)
5067 BITARRAY_SET (cases_seen, xlo);
5069 add_double (TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val),
5070 1, 0,
5071 &TREE_INT_CST_LOW (val), &TREE_INT_CST_HIGH (val));
5077 /* Given a switch statement with an expression that is an enumeration
5078 type, warn if any of the enumeration type's literals are not
5079 covered by the case expressions of the switch. Also, warn if there
5080 are any extra switch cases that are *not* elements of the
5081 enumerated type.
5083 Historical note:
5085 At one stage this function would: ``If all enumeration literals
5086 were covered by the case expressions, turn one of the expressions
5087 into the default expression since it should not be possible to fall
5088 through such a switch.''
5090 That code has since been removed as: ``This optimization is
5091 disabled because it causes valid programs to fail. ANSI C does not
5092 guarantee that an expression with enum type will have a value that
5093 is the same as one of the enumeration literals.'' */
5095 void
5096 check_for_full_enumeration_handling (type)
5097 tree type;
5099 struct case_node *n;
5100 tree chain;
5102 /* True iff the selector type is a numbered set mode. */
5103 int sparseness = 0;
5105 /* The number of possible selector values. */
5106 HOST_WIDE_INT size;
5108 /* For each possible selector value. a one iff it has been matched
5109 by a case value alternative. */
5110 unsigned char *cases_seen;
5112 /* The allocated size of cases_seen, in chars. */
5113 HOST_WIDE_INT bytes_needed;
5115 size = all_cases_count (type, &sparseness);
5116 bytes_needed = (size + HOST_BITS_PER_CHAR) / HOST_BITS_PER_CHAR;
5118 if (size > 0 && size < 600000
5119 /* We deliberately use calloc here, not cmalloc, so that we can suppress
5120 this optimization if we don't have enough memory rather than
5121 aborting, as xmalloc would do. */
5122 && (cases_seen =
5123 (unsigned char *) really_call_calloc (bytes_needed, 1)) != NULL)
5125 HOST_WIDE_INT i;
5126 tree v = TYPE_VALUES (type);
5128 /* The time complexity of this code is normally O(N), where
5129 N being the number of members in the enumerated type.
5130 However, if type is an ENUMERAL_TYPE whose values do not
5131 increase monotonically, O(N*log(N)) time may be needed. */
5133 mark_seen_cases (type, cases_seen, size, sparseness);
5135 for (i = 0; v != NULL_TREE && i < size; i++, v = TREE_CHAIN (v))
5136 if (BITARRAY_TEST (cases_seen, i) == 0)
5137 warning ("enumeration value `%s' not handled in switch",
5138 IDENTIFIER_POINTER (TREE_PURPOSE (v)));
5140 free (cases_seen);
5143 /* Now we go the other way around; we warn if there are case
5144 expressions that don't correspond to enumerators. This can
5145 occur since C and C++ don't enforce type-checking of
5146 assignments to enumeration variables. */
5148 if (case_stack->data.case_stmt.case_list
5149 && case_stack->data.case_stmt.case_list->left)
5150 case_stack->data.case_stmt.case_list
5151 = case_tree2list (case_stack->data.case_stmt.case_list, 0);
5152 for (n = case_stack->data.case_stmt.case_list; n; n = n->right)
5154 for (chain = TYPE_VALUES (type);
5155 chain && !tree_int_cst_equal (n->low, TREE_VALUE (chain));
5156 chain = TREE_CHAIN (chain))
5159 if (!chain)
5161 if (TYPE_NAME (type) == 0)
5162 warning ("case value `%ld' not in enumerated type",
5163 (long) TREE_INT_CST_LOW (n->low));
5164 else
5165 warning ("case value `%ld' not in enumerated type `%s'",
5166 (long) TREE_INT_CST_LOW (n->low),
5167 IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
5168 == IDENTIFIER_NODE)
5169 ? TYPE_NAME (type)
5170 : DECL_NAME (TYPE_NAME (type))));
5172 if (!tree_int_cst_equal (n->low, n->high))
5174 for (chain = TYPE_VALUES (type);
5175 chain && !tree_int_cst_equal (n->high, TREE_VALUE (chain));
5176 chain = TREE_CHAIN (chain))
5179 if (!chain)
5181 if (TYPE_NAME (type) == 0)
5182 warning ("case value `%ld' not in enumerated type",
5183 (long) TREE_INT_CST_LOW (n->high));
5184 else
5185 warning ("case value `%ld' not in enumerated type `%s'",
5186 (long) TREE_INT_CST_LOW (n->high),
5187 IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
5188 == IDENTIFIER_NODE)
5189 ? TYPE_NAME (type)
5190 : DECL_NAME (TYPE_NAME (type))));
5197 /* Maximum number of case bit tests. */
5198 #define MAX_CASE_BIT_TESTS 3
5200 /* By default, enable case bit tests on targets with ashlsi3. */
5201 #ifndef CASE_USE_BIT_TESTS
5202 #define CASE_USE_BIT_TESTS (ashl_optab->handlers[word_mode].insn_code \
5203 != CODE_FOR_nothing)
5204 #endif
5207 /* A case_bit_test represents a set of case nodes that may be
5208 selected from using a bit-wise comparison. HI and LO hold
5209 the integer to be tested against, LABEL contains the label
5210 to jump to upon success and BITS counts the number of case
5211 nodes handled by this test, typically the number of bits
5212 set in HI:LO. */
5214 struct case_bit_test
5216 HOST_WIDE_INT hi;
5217 HOST_WIDE_INT lo;
5218 rtx label;
5219 int bits;
5222 /* Determine whether "1 << x" is relatively cheap in word_mode. */
5224 static bool lshift_cheap_p ()
5226 static bool init = false;
5227 static bool cheap = true;
5229 if (!init)
5231 rtx reg = gen_rtx_REG (word_mode, 10000);
5232 int cost = rtx_cost (gen_rtx_ASHIFT (word_mode, const1_rtx, reg), SET);
5233 cheap = cost < COSTS_N_INSNS (3);
5234 init = true;
5237 return cheap;
5240 /* Comparison function for qsort to order bit tests by decreasing
5241 number of case nodes, i.e. the node with the most cases gets
5242 tested first. */
5244 static int case_bit_test_cmp (p1, p2)
5245 const void *p1;
5246 const void *p2;
5248 const struct case_bit_test *d1 = p1;
5249 const struct case_bit_test *d2 = p2;
5251 return d2->bits - d1->bits;
5254 /* Expand a switch statement by a short sequence of bit-wise
5255 comparisons. "switch(x)" is effectively converted into
5256 "if ((1 << (x-MINVAL)) & CST)" where CST and MINVAL are
5257 integer constants.
5259 INDEX_EXPR is the value being switched on, which is of
5260 type INDEX_TYPE. MINVAL is the lowest case value of in
5261 the case nodes, of INDEX_TYPE type, and RANGE is highest
5262 value minus MINVAL, also of type INDEX_TYPE. NODES is
5263 the set of case nodes, and DEFAULT_LABEL is the label to
5264 branch to should none of the cases match.
5266 There *MUST* be MAX_CASE_BIT_TESTS or less unique case
5267 node targets. */
5269 static void
5270 emit_case_bit_tests (index_type, index_expr, minval, range,
5271 nodes, default_label)
5272 tree index_type, index_expr, minval, range;
5273 case_node_ptr nodes;
5274 rtx default_label;
5276 struct case_bit_test test[MAX_CASE_BIT_TESTS];
5277 enum machine_mode mode;
5278 rtx expr, index, label;
5279 unsigned int i,j,lo,hi;
5280 struct case_node *n;
5281 unsigned int count;
5283 count = 0;
5284 for (n = nodes; n; n = n->right)
5286 label = label_rtx (n->code_label);
5287 for (i = 0; i < count; i++)
5288 if (same_case_target_p (label, test[i].label))
5289 break;
5291 if (i == count)
5293 if (count >= MAX_CASE_BIT_TESTS)
5294 abort ();
5295 test[i].hi = 0;
5296 test[i].lo = 0;
5297 test[i].label = label;
5298 test[i].bits = 1;
5299 count++;
5301 else
5302 test[i].bits++;
5304 lo = tree_low_cst (fold (build (MINUS_EXPR, index_type,
5305 n->low, minval)), 1);
5306 hi = tree_low_cst (fold (build (MINUS_EXPR, index_type,
5307 n->high, minval)), 1);
5308 for (j = lo; j <= hi; j++)
5309 if (j >= HOST_BITS_PER_WIDE_INT)
5310 test[i].hi |= (HOST_WIDE_INT) 1 << (j - HOST_BITS_PER_INT);
5311 else
5312 test[i].lo |= (HOST_WIDE_INT) 1 << j;
5315 qsort (test, count, sizeof(*test), case_bit_test_cmp);
5317 index_expr = fold (build (MINUS_EXPR, index_type,
5318 convert (index_type, index_expr),
5319 convert (index_type, minval)));
5320 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
5321 emit_queue ();
5322 index = protect_from_queue (index, 0);
5323 do_pending_stack_adjust ();
5325 mode = TYPE_MODE (index_type);
5326 expr = expand_expr (range, NULL_RTX, VOIDmode, 0);
5327 emit_cmp_and_jump_insns (index, expr, GTU, NULL_RTX, mode, 1,
5328 default_label);
5330 index = convert_to_mode (word_mode, index, 0);
5331 index = expand_binop (word_mode, ashl_optab, const1_rtx,
5332 index, NULL_RTX, 1, OPTAB_WIDEN);
5334 for (i = 0; i < count; i++)
5336 expr = immed_double_const (test[i].lo, test[i].hi, word_mode);
5337 expr = expand_binop (word_mode, and_optab, index, expr,
5338 NULL_RTX, 1, OPTAB_WIDEN);
5339 emit_cmp_and_jump_insns (expr, const0_rtx, NE, NULL_RTX,
5340 word_mode, 1, test[i].label);
5343 emit_jump (default_label);
5346 /* Terminate a case (Pascal) or switch (C) statement
5347 in which ORIG_INDEX is the expression to be tested.
5348 If ORIG_TYPE is not NULL, it is the original ORIG_INDEX
5349 type as given in the source before any compiler conversions.
5350 Generate the code to test it and jump to the right place. */
5352 void
5353 expand_end_case_type (orig_index, orig_type)
5354 tree orig_index, orig_type;
5356 tree minval = NULL_TREE, maxval = NULL_TREE, range = NULL_TREE;
5357 rtx default_label = 0;
5358 struct case_node *n, *m;
5359 unsigned int count, uniq;
5360 rtx index;
5361 rtx table_label;
5362 int ncases;
5363 rtx *labelvec;
5364 int i;
5365 rtx before_case, end, lab;
5366 struct nesting *thiscase = case_stack;
5367 tree index_expr, index_type;
5368 bool exit_done = false;
5369 int unsignedp;
5371 /* Don't crash due to previous errors. */
5372 if (thiscase == NULL)
5373 return;
5375 index_expr = thiscase->data.case_stmt.index_expr;
5376 index_type = TREE_TYPE (index_expr);
5377 unsignedp = TREE_UNSIGNED (index_type);
5378 if (orig_type == NULL)
5379 orig_type = TREE_TYPE (orig_index);
5381 do_pending_stack_adjust ();
5383 /* This might get a spurious warning in the presence of a syntax error;
5384 it could be fixed by moving the call to check_seenlabel after the
5385 check for error_mark_node, and copying the code of check_seenlabel that
5386 deals with case_stack->data.case_stmt.line_number_status /
5387 restore_line_number_status in front of the call to end_cleanup_deferral;
5388 However, this might miss some useful warnings in the presence of
5389 non-syntax errors. */
5390 check_seenlabel ();
5392 /* An ERROR_MARK occurs for various reasons including invalid data type. */
5393 if (index_type != error_mark_node)
5395 /* If the switch expression was an enumerated type, check that
5396 exactly all enumeration literals are covered by the cases.
5397 The check is made when -Wswitch was specified and there is no
5398 default case, or when -Wswitch-enum was specified. */
5399 if (((warn_switch && !thiscase->data.case_stmt.default_label)
5400 || warn_switch_enum)
5401 && TREE_CODE (orig_type) == ENUMERAL_TYPE
5402 && TREE_CODE (index_expr) != INTEGER_CST)
5403 check_for_full_enumeration_handling (orig_type);
5405 if (warn_switch_default && !thiscase->data.case_stmt.default_label)
5406 warning ("switch missing default case");
5408 /* If we don't have a default-label, create one here,
5409 after the body of the switch. */
5410 if (thiscase->data.case_stmt.default_label == 0)
5412 thiscase->data.case_stmt.default_label
5413 = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
5414 /* Share the exit label if possible. */
5415 if (thiscase->exit_label)
5417 SET_DECL_RTL (thiscase->data.case_stmt.default_label,
5418 thiscase->exit_label);
5419 exit_done = true;
5421 expand_label (thiscase->data.case_stmt.default_label);
5423 default_label = label_rtx (thiscase->data.case_stmt.default_label);
5425 before_case = get_last_insn ();
5427 if (thiscase->data.case_stmt.case_list
5428 && thiscase->data.case_stmt.case_list->left)
5429 thiscase->data.case_stmt.case_list
5430 = case_tree2list (thiscase->data.case_stmt.case_list, 0);
5432 /* Simplify the case-list before we count it. */
5433 group_case_nodes (thiscase->data.case_stmt.case_list);
5434 strip_default_case_nodes (&thiscase->data.case_stmt.case_list,
5435 default_label);
5437 /* Get upper and lower bounds of case values.
5438 Also convert all the case values to the index expr's data type. */
5440 uniq = 0;
5441 count = 0;
5442 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5444 /* Check low and high label values are integers. */
5445 if (TREE_CODE (n->low) != INTEGER_CST)
5446 abort ();
5447 if (TREE_CODE (n->high) != INTEGER_CST)
5448 abort ();
5450 n->low = convert (index_type, n->low);
5451 n->high = convert (index_type, n->high);
5453 /* Count the elements and track the largest and smallest
5454 of them (treating them as signed even if they are not). */
5455 if (count++ == 0)
5457 minval = n->low;
5458 maxval = n->high;
5460 else
5462 if (INT_CST_LT (n->low, minval))
5463 minval = n->low;
5464 if (INT_CST_LT (maxval, n->high))
5465 maxval = n->high;
5467 /* A range counts double, since it requires two compares. */
5468 if (! tree_int_cst_equal (n->low, n->high))
5469 count++;
5471 /* Count the number of unique case node targets. */
5472 uniq++;
5473 lab = label_rtx (n->code_label);
5474 for (m = thiscase->data.case_stmt.case_list; m != n; m = m->right)
5475 if (same_case_target_p (label_rtx (m->code_label), lab))
5477 uniq--;
5478 break;
5482 /* Compute span of values. */
5483 if (count != 0)
5484 range = fold (build (MINUS_EXPR, index_type, maxval, minval));
5486 end_cleanup_deferral ();
5488 if (count == 0)
5490 expand_expr (index_expr, const0_rtx, VOIDmode, 0);
5491 emit_queue ();
5492 emit_jump (default_label);
5495 /* Try implementing this switch statement by a short sequence of
5496 bit-wise comparisons. However, we let the binary-tree case
5497 below handle constant index expressions. */
5498 else if (CASE_USE_BIT_TESTS
5499 && ! TREE_CONSTANT (index_expr)
5500 && compare_tree_int (range, GET_MODE_BITSIZE (word_mode)) < 0
5501 && lshift_cheap_p ()
5502 && ((uniq == 1 && count >= 3)
5503 || (uniq == 2 && count >= 5)
5504 || (uniq == 3 && count >= 6)))
5506 /* Optimize the case where all the case values fit in a
5507 word without having to subtract MINVAL. In this case,
5508 we can optimize away the subtraction. */
5509 if (compare_tree_int (minval, 0) > 0
5510 && compare_tree_int (maxval, GET_MODE_BITSIZE (word_mode)) < 0)
5512 minval = integer_zero_node;
5513 range = maxval;
5515 emit_case_bit_tests (index_type, index_expr, minval, range,
5516 thiscase->data.case_stmt.case_list,
5517 default_label);
5520 /* If range of values is much bigger than number of values,
5521 make a sequence of conditional branches instead of a dispatch.
5522 If the switch-index is a constant, do it this way
5523 because we can optimize it. */
5525 else if (count < case_values_threshold ()
5526 || compare_tree_int (range, 10 * count) > 0
5527 /* RANGE may be signed, and really large ranges will show up
5528 as negative numbers. */
5529 || compare_tree_int (range, 0) < 0
5530 #ifndef ASM_OUTPUT_ADDR_DIFF_ELT
5531 || flag_pic
5532 #endif
5533 || TREE_CONSTANT (index_expr))
5535 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
5537 /* If the index is a short or char that we do not have
5538 an insn to handle comparisons directly, convert it to
5539 a full integer now, rather than letting each comparison
5540 generate the conversion. */
5542 if (GET_MODE_CLASS (GET_MODE (index)) == MODE_INT
5543 && ! have_insn_for (COMPARE, GET_MODE (index)))
5545 enum machine_mode wider_mode;
5546 for (wider_mode = GET_MODE (index); wider_mode != VOIDmode;
5547 wider_mode = GET_MODE_WIDER_MODE (wider_mode))
5548 if (have_insn_for (COMPARE, wider_mode))
5550 index = convert_to_mode (wider_mode, index, unsignedp);
5551 break;
5555 emit_queue ();
5556 do_pending_stack_adjust ();
5558 index = protect_from_queue (index, 0);
5559 if (GET_CODE (index) == MEM)
5560 index = copy_to_reg (index);
5561 if (GET_CODE (index) == CONST_INT
5562 || TREE_CODE (index_expr) == INTEGER_CST)
5564 /* Make a tree node with the proper constant value
5565 if we don't already have one. */
5566 if (TREE_CODE (index_expr) != INTEGER_CST)
5568 index_expr
5569 = build_int_2 (INTVAL (index),
5570 unsignedp || INTVAL (index) >= 0 ? 0 : -1);
5571 index_expr = convert (index_type, index_expr);
5574 /* For constant index expressions we need only
5575 issue an unconditional branch to the appropriate
5576 target code. The job of removing any unreachable
5577 code is left to the optimisation phase if the
5578 "-O" option is specified. */
5579 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5580 if (! tree_int_cst_lt (index_expr, n->low)
5581 && ! tree_int_cst_lt (n->high, index_expr))
5582 break;
5584 if (n)
5585 emit_jump (label_rtx (n->code_label));
5586 else
5587 emit_jump (default_label);
5589 else
5591 /* If the index expression is not constant we generate
5592 a binary decision tree to select the appropriate
5593 target code. This is done as follows:
5595 The list of cases is rearranged into a binary tree,
5596 nearly optimal assuming equal probability for each case.
5598 The tree is transformed into RTL, eliminating
5599 redundant test conditions at the same time.
5601 If program flow could reach the end of the
5602 decision tree an unconditional jump to the
5603 default code is emitted. */
5605 use_cost_table
5606 = (TREE_CODE (orig_type) != ENUMERAL_TYPE
5607 && estimate_case_costs (thiscase->data.case_stmt.case_list));
5608 balance_case_nodes (&thiscase->data.case_stmt.case_list, NULL);
5609 emit_case_nodes (index, thiscase->data.case_stmt.case_list,
5610 default_label, index_type);
5611 emit_jump_if_reachable (default_label);
5614 else
5616 table_label = gen_label_rtx ();
5617 if (! try_casesi (index_type, index_expr, minval, range,
5618 table_label, default_label))
5620 index_type = thiscase->data.case_stmt.nominal_type;
5622 /* Index jumptables from zero for suitable values of
5623 minval to avoid a subtraction. */
5624 if (! optimize_size
5625 && compare_tree_int (minval, 0) > 0
5626 && compare_tree_int (minval, 3) < 0)
5628 minval = integer_zero_node;
5629 range = maxval;
5632 if (! try_tablejump (index_type, index_expr, minval, range,
5633 table_label, default_label))
5634 abort ();
5637 /* Get table of labels to jump to, in order of case index. */
5639 ncases = tree_low_cst (range, 0) + 1;
5640 labelvec = (rtx *) alloca (ncases * sizeof (rtx));
5641 memset ((char *) labelvec, 0, ncases * sizeof (rtx));
5643 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5645 /* Compute the low and high bounds relative to the minimum
5646 value since that should fit in a HOST_WIDE_INT while the
5647 actual values may not. */
5648 HOST_WIDE_INT i_low
5649 = tree_low_cst (fold (build (MINUS_EXPR, index_type,
5650 n->low, minval)), 1);
5651 HOST_WIDE_INT i_high
5652 = tree_low_cst (fold (build (MINUS_EXPR, index_type,
5653 n->high, minval)), 1);
5654 HOST_WIDE_INT i;
5656 for (i = i_low; i <= i_high; i ++)
5657 labelvec[i]
5658 = gen_rtx_LABEL_REF (Pmode, label_rtx (n->code_label));
5661 /* Fill in the gaps with the default. */
5662 for (i = 0; i < ncases; i++)
5663 if (labelvec[i] == 0)
5664 labelvec[i] = gen_rtx_LABEL_REF (Pmode, default_label);
5666 /* Output the table */
5667 emit_label (table_label);
5669 if (CASE_VECTOR_PC_RELATIVE || flag_pic)
5670 emit_jump_insn (gen_rtx_ADDR_DIFF_VEC (CASE_VECTOR_MODE,
5671 gen_rtx_LABEL_REF (Pmode, table_label),
5672 gen_rtvec_v (ncases, labelvec),
5673 const0_rtx, const0_rtx));
5674 else
5675 emit_jump_insn (gen_rtx_ADDR_VEC (CASE_VECTOR_MODE,
5676 gen_rtvec_v (ncases, labelvec)));
5678 /* If the case insn drops through the table,
5679 after the table we must jump to the default-label.
5680 Otherwise record no drop-through after the table. */
5681 #ifdef CASE_DROPS_THROUGH
5682 emit_jump (default_label);
5683 #else
5684 emit_barrier ();
5685 #endif
5688 before_case = NEXT_INSN (before_case);
5689 end = get_last_insn ();
5690 if (squeeze_notes (&before_case, &end))
5691 abort ();
5692 reorder_insns (before_case, end,
5693 thiscase->data.case_stmt.start);
5695 else
5696 end_cleanup_deferral ();
5698 if (thiscase->exit_label && !exit_done)
5699 emit_label (thiscase->exit_label);
5701 POPSTACK (case_stack);
5703 free_temp_slots ();
5706 /* Convert the tree NODE into a list linked by the right field, with the left
5707 field zeroed. RIGHT is used for recursion; it is a list to be placed
5708 rightmost in the resulting list. */
5710 static struct case_node *
5711 case_tree2list (node, right)
5712 struct case_node *node, *right;
5714 struct case_node *left;
5716 if (node->right)
5717 right = case_tree2list (node->right, right);
5719 node->right = right;
5720 if ((left = node->left))
5722 node->left = 0;
5723 return case_tree2list (left, node);
5726 return node;
5729 /* Generate code to jump to LABEL if OP1 and OP2 are equal. */
5731 static void
5732 do_jump_if_equal (op1, op2, label, unsignedp)
5733 rtx op1, op2, label;
5734 int unsignedp;
5736 if (GET_CODE (op1) == CONST_INT && GET_CODE (op2) == CONST_INT)
5738 if (INTVAL (op1) == INTVAL (op2))
5739 emit_jump (label);
5741 else
5742 emit_cmp_and_jump_insns (op1, op2, EQ, NULL_RTX,
5743 (GET_MODE (op1) == VOIDmode
5744 ? GET_MODE (op2) : GET_MODE (op1)),
5745 unsignedp, label);
5748 /* Not all case values are encountered equally. This function
5749 uses a heuristic to weight case labels, in cases where that
5750 looks like a reasonable thing to do.
5752 Right now, all we try to guess is text, and we establish the
5753 following weights:
5755 chars above space: 16
5756 digits: 16
5757 default: 12
5758 space, punct: 8
5759 tab: 4
5760 newline: 2
5761 other "\" chars: 1
5762 remaining chars: 0
5764 If we find any cases in the switch that are not either -1 or in the range
5765 of valid ASCII characters, or are control characters other than those
5766 commonly used with "\", don't treat this switch scanning text.
5768 Return 1 if these nodes are suitable for cost estimation, otherwise
5769 return 0. */
5771 static int
5772 estimate_case_costs (node)
5773 case_node_ptr node;
5775 tree min_ascii = integer_minus_one_node;
5776 tree max_ascii = convert (TREE_TYPE (node->high), build_int_2 (127, 0));
5777 case_node_ptr n;
5778 int i;
5780 /* If we haven't already made the cost table, make it now. Note that the
5781 lower bound of the table is -1, not zero. */
5783 if (! cost_table_initialized)
5785 cost_table_initialized = 1;
5787 for (i = 0; i < 128; i++)
5789 if (ISALNUM (i))
5790 COST_TABLE (i) = 16;
5791 else if (ISPUNCT (i))
5792 COST_TABLE (i) = 8;
5793 else if (ISCNTRL (i))
5794 COST_TABLE (i) = -1;
5797 COST_TABLE (' ') = 8;
5798 COST_TABLE ('\t') = 4;
5799 COST_TABLE ('\0') = 4;
5800 COST_TABLE ('\n') = 2;
5801 COST_TABLE ('\f') = 1;
5802 COST_TABLE ('\v') = 1;
5803 COST_TABLE ('\b') = 1;
5806 /* See if all the case expressions look like text. It is text if the
5807 constant is >= -1 and the highest constant is <= 127. Do all comparisons
5808 as signed arithmetic since we don't want to ever access cost_table with a
5809 value less than -1. Also check that none of the constants in a range
5810 are strange control characters. */
5812 for (n = node; n; n = n->right)
5814 if ((INT_CST_LT (n->low, min_ascii)) || INT_CST_LT (max_ascii, n->high))
5815 return 0;
5817 for (i = (HOST_WIDE_INT) TREE_INT_CST_LOW (n->low);
5818 i <= (HOST_WIDE_INT) TREE_INT_CST_LOW (n->high); i++)
5819 if (COST_TABLE (i) < 0)
5820 return 0;
5823 /* All interesting values are within the range of interesting
5824 ASCII characters. */
5825 return 1;
5828 /* Determine whether two case labels branch to the same target. */
5830 static bool
5831 same_case_target_p (l1, l2)
5832 rtx l1, l2;
5834 rtx i1, i2;
5836 if (l1 == l2)
5837 return true;
5839 i1 = next_real_insn (l1);
5840 i2 = next_real_insn (l2);
5841 if (i1 == i2)
5842 return true;
5844 if (i1 && simplejump_p (i1))
5846 l1 = XEXP (SET_SRC (PATTERN (i1)), 0);
5849 if (i2 && simplejump_p (i2))
5851 l2 = XEXP (SET_SRC (PATTERN (i2)), 0);
5853 return l1 == l2;
5856 /* Delete nodes that branch to the default label from a list of
5857 case nodes. Eg. case 5: default: becomes just default: */
5859 static void
5860 strip_default_case_nodes (prev, deflab)
5861 case_node_ptr *prev;
5862 rtx deflab;
5864 case_node_ptr ptr;
5866 while (*prev)
5868 ptr = *prev;
5869 if (same_case_target_p (label_rtx (ptr->code_label), deflab))
5870 *prev = ptr->right;
5871 else
5872 prev = &ptr->right;
5876 /* Scan an ordered list of case nodes
5877 combining those with consecutive values or ranges.
5879 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
5881 static void
5882 group_case_nodes (head)
5883 case_node_ptr head;
5885 case_node_ptr node = head;
5887 while (node)
5889 rtx lab = label_rtx (node->code_label);
5890 case_node_ptr np = node;
5892 /* Try to group the successors of NODE with NODE. */
5893 while (((np = np->right) != 0)
5894 /* Do they jump to the same place? */
5895 && same_case_target_p (label_rtx (np->code_label), lab)
5896 /* Are their ranges consecutive? */
5897 && tree_int_cst_equal (np->low,
5898 fold (build (PLUS_EXPR,
5899 TREE_TYPE (node->high),
5900 node->high,
5901 integer_one_node)))
5902 /* An overflow is not consecutive. */
5903 && tree_int_cst_lt (node->high,
5904 fold (build (PLUS_EXPR,
5905 TREE_TYPE (node->high),
5906 node->high,
5907 integer_one_node))))
5909 node->high = np->high;
5911 /* NP is the first node after NODE which can't be grouped with it.
5912 Delete the nodes in between, and move on to that node. */
5913 node->right = np;
5914 node = np;
5918 /* Take an ordered list of case nodes
5919 and transform them into a near optimal binary tree,
5920 on the assumption that any target code selection value is as
5921 likely as any other.
5923 The transformation is performed by splitting the ordered
5924 list into two equal sections plus a pivot. The parts are
5925 then attached to the pivot as left and right branches. Each
5926 branch is then transformed recursively. */
5928 static void
5929 balance_case_nodes (head, parent)
5930 case_node_ptr *head;
5931 case_node_ptr parent;
5933 case_node_ptr np;
5935 np = *head;
5936 if (np)
5938 int cost = 0;
5939 int i = 0;
5940 int ranges = 0;
5941 case_node_ptr *npp;
5942 case_node_ptr left;
5944 /* Count the number of entries on branch. Also count the ranges. */
5946 while (np)
5948 if (!tree_int_cst_equal (np->low, np->high))
5950 ranges++;
5951 if (use_cost_table)
5952 cost += COST_TABLE (TREE_INT_CST_LOW (np->high));
5955 if (use_cost_table)
5956 cost += COST_TABLE (TREE_INT_CST_LOW (np->low));
5958 i++;
5959 np = np->right;
5962 if (i > 2)
5964 /* Split this list if it is long enough for that to help. */
5965 npp = head;
5966 left = *npp;
5967 if (use_cost_table)
5969 /* Find the place in the list that bisects the list's total cost,
5970 Here I gets half the total cost. */
5971 int n_moved = 0;
5972 i = (cost + 1) / 2;
5973 while (1)
5975 /* Skip nodes while their cost does not reach that amount. */
5976 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
5977 i -= COST_TABLE (TREE_INT_CST_LOW ((*npp)->high));
5978 i -= COST_TABLE (TREE_INT_CST_LOW ((*npp)->low));
5979 if (i <= 0)
5980 break;
5981 npp = &(*npp)->right;
5982 n_moved += 1;
5984 if (n_moved == 0)
5986 /* Leave this branch lopsided, but optimize left-hand
5987 side and fill in `parent' fields for right-hand side. */
5988 np = *head;
5989 np->parent = parent;
5990 balance_case_nodes (&np->left, np);
5991 for (; np->right; np = np->right)
5992 np->right->parent = np;
5993 return;
5996 /* If there are just three nodes, split at the middle one. */
5997 else if (i == 3)
5998 npp = &(*npp)->right;
5999 else
6001 /* Find the place in the list that bisects the list's total cost,
6002 where ranges count as 2.
6003 Here I gets half the total cost. */
6004 i = (i + ranges + 1) / 2;
6005 while (1)
6007 /* Skip nodes while their cost does not reach that amount. */
6008 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
6009 i--;
6010 i--;
6011 if (i <= 0)
6012 break;
6013 npp = &(*npp)->right;
6016 *head = np = *npp;
6017 *npp = 0;
6018 np->parent = parent;
6019 np->left = left;
6021 /* Optimize each of the two split parts. */
6022 balance_case_nodes (&np->left, np);
6023 balance_case_nodes (&np->right, np);
6025 else
6027 /* Else leave this branch as one level,
6028 but fill in `parent' fields. */
6029 np = *head;
6030 np->parent = parent;
6031 for (; np->right; np = np->right)
6032 np->right->parent = np;
6037 /* Search the parent sections of the case node tree
6038 to see if a test for the lower bound of NODE would be redundant.
6039 INDEX_TYPE is the type of the index expression.
6041 The instructions to generate the case decision tree are
6042 output in the same order as nodes are processed so it is
6043 known that if a parent node checks the range of the current
6044 node minus one that the current node is bounded at its lower
6045 span. Thus the test would be redundant. */
6047 static int
6048 node_has_low_bound (node, index_type)
6049 case_node_ptr node;
6050 tree index_type;
6052 tree low_minus_one;
6053 case_node_ptr pnode;
6055 /* If the lower bound of this node is the lowest value in the index type,
6056 we need not test it. */
6058 if (tree_int_cst_equal (node->low, TYPE_MIN_VALUE (index_type)))
6059 return 1;
6061 /* If this node has a left branch, the value at the left must be less
6062 than that at this node, so it cannot be bounded at the bottom and
6063 we need not bother testing any further. */
6065 if (node->left)
6066 return 0;
6068 low_minus_one = fold (build (MINUS_EXPR, TREE_TYPE (node->low),
6069 node->low, integer_one_node));
6071 /* If the subtraction above overflowed, we can't verify anything.
6072 Otherwise, look for a parent that tests our value - 1. */
6074 if (! tree_int_cst_lt (low_minus_one, node->low))
6075 return 0;
6077 for (pnode = node->parent; pnode; pnode = pnode->parent)
6078 if (tree_int_cst_equal (low_minus_one, pnode->high))
6079 return 1;
6081 return 0;
6084 /* Search the parent sections of the case node tree
6085 to see if a test for the upper bound of NODE would be redundant.
6086 INDEX_TYPE is the type of the index expression.
6088 The instructions to generate the case decision tree are
6089 output in the same order as nodes are processed so it is
6090 known that if a parent node checks the range of the current
6091 node plus one that the current node is bounded at its upper
6092 span. Thus the test would be redundant. */
6094 static int
6095 node_has_high_bound (node, index_type)
6096 case_node_ptr node;
6097 tree index_type;
6099 tree high_plus_one;
6100 case_node_ptr pnode;
6102 /* If there is no upper bound, obviously no test is needed. */
6104 if (TYPE_MAX_VALUE (index_type) == NULL)
6105 return 1;
6107 /* If the upper bound of this node is the highest value in the type
6108 of the index expression, we need not test against it. */
6110 if (tree_int_cst_equal (node->high, TYPE_MAX_VALUE (index_type)))
6111 return 1;
6113 /* If this node has a right branch, the value at the right must be greater
6114 than that at this node, so it cannot be bounded at the top and
6115 we need not bother testing any further. */
6117 if (node->right)
6118 return 0;
6120 high_plus_one = fold (build (PLUS_EXPR, TREE_TYPE (node->high),
6121 node->high, integer_one_node));
6123 /* If the addition above overflowed, we can't verify anything.
6124 Otherwise, look for a parent that tests our value + 1. */
6126 if (! tree_int_cst_lt (node->high, high_plus_one))
6127 return 0;
6129 for (pnode = node->parent; pnode; pnode = pnode->parent)
6130 if (tree_int_cst_equal (high_plus_one, pnode->low))
6131 return 1;
6133 return 0;
6136 /* Search the parent sections of the
6137 case node tree to see if both tests for the upper and lower
6138 bounds of NODE would be redundant. */
6140 static int
6141 node_is_bounded (node, index_type)
6142 case_node_ptr node;
6143 tree index_type;
6145 return (node_has_low_bound (node, index_type)
6146 && node_has_high_bound (node, index_type));
6149 /* Emit an unconditional jump to LABEL unless it would be dead code. */
6151 static void
6152 emit_jump_if_reachable (label)
6153 rtx label;
6155 if (GET_CODE (get_last_insn ()) != BARRIER)
6156 emit_jump (label);
6159 /* Emit step-by-step code to select a case for the value of INDEX.
6160 The thus generated decision tree follows the form of the
6161 case-node binary tree NODE, whose nodes represent test conditions.
6162 INDEX_TYPE is the type of the index of the switch.
6164 Care is taken to prune redundant tests from the decision tree
6165 by detecting any boundary conditions already checked by
6166 emitted rtx. (See node_has_high_bound, node_has_low_bound
6167 and node_is_bounded, above.)
6169 Where the test conditions can be shown to be redundant we emit
6170 an unconditional jump to the target code. As a further
6171 optimization, the subordinates of a tree node are examined to
6172 check for bounded nodes. In this case conditional and/or
6173 unconditional jumps as a result of the boundary check for the
6174 current node are arranged to target the subordinates associated
6175 code for out of bound conditions on the current node.
6177 We can assume that when control reaches the code generated here,
6178 the index value has already been compared with the parents
6179 of this node, and determined to be on the same side of each parent
6180 as this node is. Thus, if this node tests for the value 51,
6181 and a parent tested for 52, we don't need to consider
6182 the possibility of a value greater than 51. If another parent
6183 tests for the value 50, then this node need not test anything. */
6185 static void
6186 emit_case_nodes (index, node, default_label, index_type)
6187 rtx index;
6188 case_node_ptr node;
6189 rtx default_label;
6190 tree index_type;
6192 /* If INDEX has an unsigned type, we must make unsigned branches. */
6193 int unsignedp = TREE_UNSIGNED (index_type);
6194 enum machine_mode mode = GET_MODE (index);
6195 enum machine_mode imode = TYPE_MODE (index_type);
6197 /* See if our parents have already tested everything for us.
6198 If they have, emit an unconditional jump for this node. */
6199 if (node_is_bounded (node, index_type))
6200 emit_jump (label_rtx (node->code_label));
6202 else if (tree_int_cst_equal (node->low, node->high))
6204 /* Node is single valued. First see if the index expression matches
6205 this node and then check our children, if any. */
6207 do_jump_if_equal (index,
6208 convert_modes (mode, imode,
6209 expand_expr (node->low, NULL_RTX,
6210 VOIDmode, 0),
6211 unsignedp),
6212 label_rtx (node->code_label), unsignedp);
6214 if (node->right != 0 && node->left != 0)
6216 /* This node has children on both sides.
6217 Dispatch to one side or the other
6218 by comparing the index value with this node's value.
6219 If one subtree is bounded, check that one first,
6220 so we can avoid real branches in the tree. */
6222 if (node_is_bounded (node->right, index_type))
6224 emit_cmp_and_jump_insns (index,
6225 convert_modes
6226 (mode, imode,
6227 expand_expr (node->high, NULL_RTX,
6228 VOIDmode, 0),
6229 unsignedp),
6230 GT, NULL_RTX, mode, unsignedp,
6231 label_rtx (node->right->code_label));
6232 emit_case_nodes (index, node->left, default_label, index_type);
6235 else if (node_is_bounded (node->left, index_type))
6237 emit_cmp_and_jump_insns (index,
6238 convert_modes
6239 (mode, imode,
6240 expand_expr (node->high, NULL_RTX,
6241 VOIDmode, 0),
6242 unsignedp),
6243 LT, NULL_RTX, mode, unsignedp,
6244 label_rtx (node->left->code_label));
6245 emit_case_nodes (index, node->right, default_label, index_type);
6248 else
6250 /* Neither node is bounded. First distinguish the two sides;
6251 then emit the code for one side at a time. */
6253 tree test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
6255 /* See if the value is on the right. */
6256 emit_cmp_and_jump_insns (index,
6257 convert_modes
6258 (mode, imode,
6259 expand_expr (node->high, NULL_RTX,
6260 VOIDmode, 0),
6261 unsignedp),
6262 GT, NULL_RTX, mode, unsignedp,
6263 label_rtx (test_label));
6265 /* Value must be on the left.
6266 Handle the left-hand subtree. */
6267 emit_case_nodes (index, node->left, default_label, index_type);
6268 /* If left-hand subtree does nothing,
6269 go to default. */
6270 emit_jump_if_reachable (default_label);
6272 /* Code branches here for the right-hand subtree. */
6273 expand_label (test_label);
6274 emit_case_nodes (index, node->right, default_label, index_type);
6278 else if (node->right != 0 && node->left == 0)
6280 /* Here we have a right child but no left so we issue conditional
6281 branch to default and process the right child.
6283 Omit the conditional branch to default if we it avoid only one
6284 right child; it costs too much space to save so little time. */
6286 if (node->right->right || node->right->left
6287 || !tree_int_cst_equal (node->right->low, node->right->high))
6289 if (!node_has_low_bound (node, index_type))
6291 emit_cmp_and_jump_insns (index,
6292 convert_modes
6293 (mode, imode,
6294 expand_expr (node->high, NULL_RTX,
6295 VOIDmode, 0),
6296 unsignedp),
6297 LT, NULL_RTX, mode, unsignedp,
6298 default_label);
6301 emit_case_nodes (index, node->right, default_label, index_type);
6303 else
6304 /* We cannot process node->right normally
6305 since we haven't ruled out the numbers less than
6306 this node's value. So handle node->right explicitly. */
6307 do_jump_if_equal (index,
6308 convert_modes
6309 (mode, imode,
6310 expand_expr (node->right->low, NULL_RTX,
6311 VOIDmode, 0),
6312 unsignedp),
6313 label_rtx (node->right->code_label), unsignedp);
6316 else if (node->right == 0 && node->left != 0)
6318 /* Just one subtree, on the left. */
6319 if (node->left->left || node->left->right
6320 || !tree_int_cst_equal (node->left->low, node->left->high))
6322 if (!node_has_high_bound (node, index_type))
6324 emit_cmp_and_jump_insns (index,
6325 convert_modes
6326 (mode, imode,
6327 expand_expr (node->high, NULL_RTX,
6328 VOIDmode, 0),
6329 unsignedp),
6330 GT, NULL_RTX, mode, unsignedp,
6331 default_label);
6334 emit_case_nodes (index, node->left, default_label, index_type);
6336 else
6337 /* We cannot process node->left normally
6338 since we haven't ruled out the numbers less than
6339 this node's value. So handle node->left explicitly. */
6340 do_jump_if_equal (index,
6341 convert_modes
6342 (mode, imode,
6343 expand_expr (node->left->low, NULL_RTX,
6344 VOIDmode, 0),
6345 unsignedp),
6346 label_rtx (node->left->code_label), unsignedp);
6349 else
6351 /* Node is a range. These cases are very similar to those for a single
6352 value, except that we do not start by testing whether this node
6353 is the one to branch to. */
6355 if (node->right != 0 && node->left != 0)
6357 /* Node has subtrees on both sides.
6358 If the right-hand subtree is bounded,
6359 test for it first, since we can go straight there.
6360 Otherwise, we need to make a branch in the control structure,
6361 then handle the two subtrees. */
6362 tree test_label = 0;
6364 if (node_is_bounded (node->right, index_type))
6365 /* Right hand node is fully bounded so we can eliminate any
6366 testing and branch directly to the target code. */
6367 emit_cmp_and_jump_insns (index,
6368 convert_modes
6369 (mode, imode,
6370 expand_expr (node->high, NULL_RTX,
6371 VOIDmode, 0),
6372 unsignedp),
6373 GT, NULL_RTX, mode, unsignedp,
6374 label_rtx (node->right->code_label));
6375 else
6377 /* Right hand node requires testing.
6378 Branch to a label where we will handle it later. */
6380 test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
6381 emit_cmp_and_jump_insns (index,
6382 convert_modes
6383 (mode, imode,
6384 expand_expr (node->high, NULL_RTX,
6385 VOIDmode, 0),
6386 unsignedp),
6387 GT, NULL_RTX, mode, unsignedp,
6388 label_rtx (test_label));
6391 /* Value belongs to this node or to the left-hand subtree. */
6393 emit_cmp_and_jump_insns (index,
6394 convert_modes
6395 (mode, imode,
6396 expand_expr (node->low, NULL_RTX,
6397 VOIDmode, 0),
6398 unsignedp),
6399 GE, NULL_RTX, mode, unsignedp,
6400 label_rtx (node->code_label));
6402 /* Handle the left-hand subtree. */
6403 emit_case_nodes (index, node->left, default_label, index_type);
6405 /* If right node had to be handled later, do that now. */
6407 if (test_label)
6409 /* If the left-hand subtree fell through,
6410 don't let it fall into the right-hand subtree. */
6411 emit_jump_if_reachable (default_label);
6413 expand_label (test_label);
6414 emit_case_nodes (index, node->right, default_label, index_type);
6418 else if (node->right != 0 && node->left == 0)
6420 /* Deal with values to the left of this node,
6421 if they are possible. */
6422 if (!node_has_low_bound (node, index_type))
6424 emit_cmp_and_jump_insns (index,
6425 convert_modes
6426 (mode, imode,
6427 expand_expr (node->low, NULL_RTX,
6428 VOIDmode, 0),
6429 unsignedp),
6430 LT, NULL_RTX, mode, unsignedp,
6431 default_label);
6434 /* Value belongs to this node or to the right-hand subtree. */
6436 emit_cmp_and_jump_insns (index,
6437 convert_modes
6438 (mode, imode,
6439 expand_expr (node->high, NULL_RTX,
6440 VOIDmode, 0),
6441 unsignedp),
6442 LE, NULL_RTX, mode, unsignedp,
6443 label_rtx (node->code_label));
6445 emit_case_nodes (index, node->right, default_label, index_type);
6448 else if (node->right == 0 && node->left != 0)
6450 /* Deal with values to the right of this node,
6451 if they are possible. */
6452 if (!node_has_high_bound (node, index_type))
6454 emit_cmp_and_jump_insns (index,
6455 convert_modes
6456 (mode, imode,
6457 expand_expr (node->high, NULL_RTX,
6458 VOIDmode, 0),
6459 unsignedp),
6460 GT, NULL_RTX, mode, unsignedp,
6461 default_label);
6464 /* Value belongs to this node or to the left-hand subtree. */
6466 emit_cmp_and_jump_insns (index,
6467 convert_modes
6468 (mode, imode,
6469 expand_expr (node->low, NULL_RTX,
6470 VOIDmode, 0),
6471 unsignedp),
6472 GE, NULL_RTX, mode, unsignedp,
6473 label_rtx (node->code_label));
6475 emit_case_nodes (index, node->left, default_label, index_type);
6478 else
6480 /* Node has no children so we check low and high bounds to remove
6481 redundant tests. Only one of the bounds can exist,
6482 since otherwise this node is bounded--a case tested already. */
6483 int high_bound = node_has_high_bound (node, index_type);
6484 int low_bound = node_has_low_bound (node, index_type);
6486 if (!high_bound && low_bound)
6488 emit_cmp_and_jump_insns (index,
6489 convert_modes
6490 (mode, imode,
6491 expand_expr (node->high, NULL_RTX,
6492 VOIDmode, 0),
6493 unsignedp),
6494 GT, NULL_RTX, mode, unsignedp,
6495 default_label);
6498 else if (!low_bound && high_bound)
6500 emit_cmp_and_jump_insns (index,
6501 convert_modes
6502 (mode, imode,
6503 expand_expr (node->low, NULL_RTX,
6504 VOIDmode, 0),
6505 unsignedp),
6506 LT, NULL_RTX, mode, unsignedp,
6507 default_label);
6509 else if (!low_bound && !high_bound)
6511 /* Widen LOW and HIGH to the same width as INDEX. */
6512 tree type = (*lang_hooks.types.type_for_mode) (mode, unsignedp);
6513 tree low = build1 (CONVERT_EXPR, type, node->low);
6514 tree high = build1 (CONVERT_EXPR, type, node->high);
6515 rtx low_rtx, new_index, new_bound;
6517 /* Instead of doing two branches, emit one unsigned branch for
6518 (index-low) > (high-low). */
6519 low_rtx = expand_expr (low, NULL_RTX, mode, 0);
6520 new_index = expand_simple_binop (mode, MINUS, index, low_rtx,
6521 NULL_RTX, unsignedp,
6522 OPTAB_WIDEN);
6523 new_bound = expand_expr (fold (build (MINUS_EXPR, type,
6524 high, low)),
6525 NULL_RTX, mode, 0);
6527 emit_cmp_and_jump_insns (new_index, new_bound, GT, NULL_RTX,
6528 mode, 1, default_label);
6531 emit_jump (label_rtx (node->code_label));
6536 #include "gt-stmt.h"