1 /* Expands front end tree to back end RTL for GCC
2 Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997,
3 1998, 1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
22 /* This file handles the generation of rtl code from tree structure
23 above the level of expressions, using subroutines in exp*.c and emit-rtl.c.
24 It also creates the rtl expressions for parameters and auto variables
25 and has full responsibility for allocating stack slots.
27 The functions whose names start with `expand_' are called by the
28 parser to generate RTL instructions for various kinds of constructs.
30 Some control and binding constructs require calling several such
31 functions at different times. For example, a simple if-then
32 is expanded by calling `expand_start_cond' (with the condition-expression
33 as argument) before parsing the then-clause and calling `expand_end_cond'
34 after parsing the then-clause. */
38 #include "coretypes.h"
47 #include "insn-config.h"
50 #include "hard-reg-set.h"
57 #include "langhooks.h"
61 /* Assume that case vectors are not pc-relative. */
62 #ifndef CASE_VECTOR_PC_RELATIVE
63 #define CASE_VECTOR_PC_RELATIVE 0
66 /* Functions and data structures for expanding case statements. */
68 /* Case label structure, used to hold info on labels within case
69 statements. We handle "range" labels; for a single-value label
70 as in C, the high and low limits are the same.
72 An AVL tree of case nodes is initially created, and later transformed
73 to a list linked via the RIGHT fields in the nodes. Nodes with
74 higher case values are later in the list.
76 Switch statements can be output in one of two forms. A branch table
77 is used if there are more than a few labels and the labels are dense
78 within the range between the smallest and largest case value. If a
79 branch table is used, no further manipulations are done with the case
82 The alternative to the use of a branch table is to generate a series
83 of compare and jump insns. When that is done, we use the LEFT, RIGHT,
84 and PARENT fields to hold a binary tree. Initially the tree is
85 totally unbalanced, with everything on the right. We balance the tree
86 with nodes on the left having lower case values than the parent
87 and nodes on the right having higher values. We then output the tree
90 struct case_node GTY(())
92 struct case_node *left; /* Left son in binary tree */
93 struct case_node *right; /* Right son in binary tree; also node chain */
94 struct case_node *parent; /* Parent of node in binary tree */
95 tree low; /* Lowest index value for this label */
96 tree high; /* Highest index value for this label */
97 tree code_label; /* Label to jump to when node matches */
101 typedef struct case_node case_node;
102 typedef struct case_node *case_node_ptr;
104 /* These are used by estimate_case_costs and balance_case_nodes. */
106 /* This must be a signed type, and non-ANSI compilers lack signed char. */
107 static short cost_table_[129];
108 static int use_cost_table;
109 static int cost_table_initialized;
111 /* Special care is needed because we allow -1, but TREE_INT_CST_LOW
113 #define COST_TABLE(I) cost_table_[(unsigned HOST_WIDE_INT) ((I) + 1)]
115 /* Stack of control and binding constructs we are currently inside.
117 These constructs begin when you call `expand_start_WHATEVER'
118 and end when you call `expand_end_WHATEVER'. This stack records
119 info about how the construct began that tells the end-function
120 what to do. It also may provide information about the construct
121 to alter the behavior of other constructs within the body.
122 For example, they may affect the behavior of C `break' and `continue'.
124 Each construct gets one `struct nesting' object.
125 All of these objects are chained through the `all' field.
126 `nesting_stack' points to the first object (innermost construct).
127 The position of an entry on `nesting_stack' is in its `depth' field.
129 Each type of construct has its own individual stack.
130 For example, loops have `loop_stack'. Each object points to the
131 next object of the same type through the `next' field.
133 Some constructs are visible to `break' exit-statements and others
134 are not. Which constructs are visible depends on the language.
135 Therefore, the data structure allows each construct to be visible
136 or not, according to the args given when the construct is started.
137 The construct is visible if the `exit_label' field is non-null.
138 In that case, the value should be a CODE_LABEL rtx. */
140 struct nesting GTY(())
143 struct nesting *next;
154 /* For conds (if-then and if-then-else statements). */
157 /* Label for the end of the if construct.
158 There is none if EXITFLAG was not set
159 and no `else' has been seen yet. */
161 /* Label for the end of this alternative.
162 This may be the end of the if or the next else/elseif. */
164 } GTY ((tag ("COND_NESTING"))) cond;
168 /* Label at the top of the loop; place to loop back to. */
170 /* Label at the end of the whole construct. */
172 /* Label for `continue' statement to jump to;
173 this is in front of the stepper of the loop. */
175 } GTY ((tag ("LOOP_NESTING"))) loop;
176 /* For variable binding contours. */
179 /* Sequence number of this binding contour within the function,
180 in order of entry. */
181 int block_start_count;
182 /* Nonzero => value to restore stack to on exit. */
184 /* The NOTE that starts this contour.
185 Used by expand_goto to check whether the destination
186 is within each contour or not. */
188 /* Innermost containing binding contour that has a stack level. */
189 struct nesting *innermost_stack_block;
190 /* List of cleanups to be run on exit from this contour.
191 This is a list of expressions to be evaluated.
192 The TREE_PURPOSE of each link is the ..._DECL node
193 which the cleanup pertains to. */
195 /* List of cleanup-lists of blocks containing this block,
196 as they were at the locus where this block appears.
197 There is an element for each containing block,
198 ordered innermost containing block first.
199 The tail of this list can be 0,
200 if all remaining elements would be empty lists.
201 The element's TREE_VALUE is the cleanup-list of that block,
202 which may be null. */
204 /* Chain of labels defined inside this binding contour.
205 For contours that have stack levels or cleanups. */
206 struct label_chain *label_chain;
207 /* Nonzero if this is associated with an EH region. */
208 int exception_region;
209 /* The saved target_temp_slot_level from our outer block.
210 We may reset target_temp_slot_level to be the level of
211 this block, if that is done, target_temp_slot_level
212 reverts to the saved target_temp_slot_level at the very
214 int block_target_temp_slot_level;
215 /* True if we are currently emitting insns in an area of
216 output code that is controlled by a conditional
217 expression. This is used by the cleanup handling code to
218 generate conditional cleanup actions. */
219 int conditional_code;
220 /* A place to move the start of the exception region for any
221 of the conditional cleanups, must be at the end or after
222 the start of the last unconditional cleanup, and before any
223 conditional branch points. */
224 rtx last_unconditional_cleanup;
225 } GTY ((tag ("BLOCK_NESTING"))) block;
226 /* For switch (C) or case (Pascal) statements,
227 and also for dummies (see `expand_start_case_dummy'). */
230 /* The insn after which the case dispatch should finally
231 be emitted. Zero for a dummy. */
233 /* A list of case labels; it is first built as an AVL tree.
234 During expand_end_case, this is converted to a list, and may be
235 rearranged into a nearly balanced binary tree. */
236 struct case_node *case_list;
237 /* Label to jump to if no case matches. */
239 /* The expression to be dispatched on. */
241 /* Type that INDEX_EXPR should be converted to. */
243 /* Name of this kind of statement, for warnings. */
244 const char *printname;
245 /* Used to save no_line_numbers till we see the first case label.
246 We set this to -1 when we see the first case label in this
248 int line_number_status;
249 } GTY ((tag ("CASE_NESTING"))) case_stmt;
250 } GTY ((desc ("%1.desc"))) data;
253 /* Allocate and return a new `struct nesting'. */
255 #define ALLOC_NESTING() \
256 (struct nesting *) ggc_alloc (sizeof (struct nesting))
258 /* Pop the nesting stack element by element until we pop off
259 the element which is at the top of STACK.
260 Update all the other stacks, popping off elements from them
261 as we pop them from nesting_stack. */
263 #define POPSTACK(STACK) \
264 do { struct nesting *target = STACK; \
265 struct nesting *this; \
266 do { this = nesting_stack; \
267 if (loop_stack == this) \
268 loop_stack = loop_stack->next; \
269 if (cond_stack == this) \
270 cond_stack = cond_stack->next; \
271 if (block_stack == this) \
272 block_stack = block_stack->next; \
273 if (stack_block_stack == this) \
274 stack_block_stack = stack_block_stack->next; \
275 if (case_stack == this) \
276 case_stack = case_stack->next; \
277 nesting_depth = nesting_stack->depth - 1; \
278 nesting_stack = this->all; } \
279 while (this != target); } while (0)
281 /* In some cases it is impossible to generate code for a forward goto
282 until the label definition is seen. This happens when it may be necessary
283 for the goto to reset the stack pointer: we don't yet know how to do that.
284 So expand_goto puts an entry on this fixup list.
285 Each time a binding contour that resets the stack is exited,
287 If the target label has now been defined, we can insert the proper code. */
289 struct goto_fixup GTY(())
291 /* Points to following fixup. */
292 struct goto_fixup *next;
293 /* Points to the insn before the jump insn.
294 If more code must be inserted, it goes after this insn. */
296 /* The LABEL_DECL that this jump is jumping to, or 0
297 for break, continue or return. */
299 /* The BLOCK for the place where this goto was found. */
301 /* The CODE_LABEL rtx that this is jumping to. */
303 /* Number of binding contours started in current function
304 before the label reference. */
305 int block_start_count;
306 /* The outermost stack level that should be restored for this jump.
307 Each time a binding contour that resets the stack is exited,
308 if the target label is *not* yet defined, this slot is updated. */
310 /* List of lists of cleanup expressions to be run by this goto.
311 There is one element for each block that this goto is within.
312 The tail of this list can be 0,
313 if all remaining elements would be empty.
314 The TREE_VALUE contains the cleanup list of that block as of the
315 time this goto was seen.
316 The TREE_ADDRESSABLE flag is 1 for a block that has been exited. */
317 tree cleanup_list_list;
320 /* Within any binding contour that must restore a stack level,
321 all labels are recorded with a chain of these structures. */
323 struct label_chain GTY(())
325 /* Points to following fixup. */
326 struct label_chain *next;
330 struct stmt_status GTY(())
332 /* Chain of all pending binding contours. */
333 struct nesting * x_block_stack;
335 /* If any new stacks are added here, add them to POPSTACKS too. */
337 /* Chain of all pending binding contours that restore stack levels
339 struct nesting * x_stack_block_stack;
341 /* Chain of all pending conditional statements. */
342 struct nesting * x_cond_stack;
344 /* Chain of all pending loops. */
345 struct nesting * x_loop_stack;
347 /* Chain of all pending case or switch statements. */
348 struct nesting * x_case_stack;
350 /* Separate chain including all of the above,
351 chained through the `all' field. */
352 struct nesting * x_nesting_stack;
354 /* Number of entries on nesting_stack now. */
357 /* Number of binding contours started so far in this function. */
358 int x_block_start_count;
360 /* Each time we expand an expression-statement,
361 record the expr's type and its RTL value here. */
362 tree x_last_expr_type;
363 rtx x_last_expr_value;
365 /* Nonzero if within a ({...}) grouping, in which case we must
366 always compute a value for each expr-stmt in case it is the last one. */
367 int x_expr_stmts_for_value;
369 /* Location of last line-number note, whether we actually
370 emitted it or not. */
371 location_t x_emit_locus;
373 struct goto_fixup *x_goto_fixup_chain;
376 #define block_stack (cfun->stmt->x_block_stack)
377 #define stack_block_stack (cfun->stmt->x_stack_block_stack)
378 #define cond_stack (cfun->stmt->x_cond_stack)
379 #define loop_stack (cfun->stmt->x_loop_stack)
380 #define case_stack (cfun->stmt->x_case_stack)
381 #define nesting_stack (cfun->stmt->x_nesting_stack)
382 #define nesting_depth (cfun->stmt->x_nesting_depth)
383 #define current_block_start_count (cfun->stmt->x_block_start_count)
384 #define last_expr_type (cfun->stmt->x_last_expr_type)
385 #define last_expr_value (cfun->stmt->x_last_expr_value)
386 #define expr_stmts_for_value (cfun->stmt->x_expr_stmts_for_value)
387 #define emit_locus (cfun->stmt->x_emit_locus)
388 #define goto_fixup_chain (cfun->stmt->x_goto_fixup_chain)
390 /* Nonzero if we are using EH to handle cleanups. */
391 static int using_eh_for_cleanups_p = 0;
393 static int n_occurrences PARAMS ((int, const char *));
394 static bool parse_input_constraint PARAMS ((const char **, int, int, int,
395 int, const char * const *,
397 static bool decl_conflicts_with_clobbers_p PARAMS ((tree, const HARD_REG_SET));
398 static void expand_goto_internal PARAMS ((tree, rtx, rtx));
399 static int expand_fixup PARAMS ((tree, rtx, rtx));
400 static rtx expand_nl_handler_label PARAMS ((rtx, rtx));
401 static void expand_nl_goto_receiver PARAMS ((void));
402 static void expand_nl_goto_receivers PARAMS ((struct nesting *));
403 static void fixup_gotos PARAMS ((struct nesting *, rtx, tree,
405 static bool check_operand_nalternatives PARAMS ((tree, tree));
406 static bool check_unique_operand_names PARAMS ((tree, tree));
407 static char *resolve_operand_name_1 PARAMS ((char *, tree, tree));
408 static void expand_null_return_1 PARAMS ((rtx));
409 static enum br_predictor return_prediction PARAMS ((rtx));
410 static void expand_value_return PARAMS ((rtx));
411 static int tail_recursion_args PARAMS ((tree, tree));
412 static void expand_cleanups PARAMS ((tree, int, int));
413 static void check_seenlabel PARAMS ((void));
414 static void do_jump_if_equal PARAMS ((rtx, rtx, rtx, int));
415 static int estimate_case_costs PARAMS ((case_node_ptr));
416 static bool same_case_target_p PARAMS ((rtx, rtx));
417 static void strip_default_case_nodes PARAMS ((case_node_ptr *, rtx));
418 static bool lshift_cheap_p PARAMS ((void));
419 static int case_bit_test_cmp PARAMS ((const void *, const void *));
420 static void emit_case_bit_tests PARAMS ((tree, tree, tree, tree,
421 case_node_ptr, rtx));
422 static void group_case_nodes PARAMS ((case_node_ptr));
423 static void balance_case_nodes PARAMS ((case_node_ptr *,
425 static int node_has_low_bound PARAMS ((case_node_ptr, tree));
426 static int node_has_high_bound PARAMS ((case_node_ptr, tree));
427 static int node_is_bounded PARAMS ((case_node_ptr, tree));
428 static void emit_jump_if_reachable PARAMS ((rtx));
429 static void emit_case_nodes PARAMS ((rtx, case_node_ptr, rtx, tree));
430 static struct case_node *case_tree2list PARAMS ((case_node *, case_node *));
433 using_eh_for_cleanups ()
435 using_eh_for_cleanups_p = 1;
439 init_stmt_for_function ()
441 cfun->stmt = ((struct stmt_status *)ggc_alloc (sizeof (struct stmt_status)));
443 /* We are not currently within any block, conditional, loop or case. */
445 stack_block_stack = 0;
452 current_block_start_count = 0;
454 /* No gotos have been expanded yet. */
455 goto_fixup_chain = 0;
457 /* We are not processing a ({...}) grouping. */
458 expr_stmts_for_value = 0;
462 /* Record the current file and line. Called from emit_line_note. */
464 set_file_and_line_for_stmt (file, line)
468 /* If we're outputting an inline function, and we add a line note,
469 there may be no CFUN->STMT information. So, there's no need to
473 emit_locus.file = file;
474 emit_locus.line = line;
478 /* Emit a no-op instruction. */
485 last_insn = get_last_insn ();
487 && (GET_CODE (last_insn) == CODE_LABEL
488 || (GET_CODE (last_insn) == NOTE
489 && prev_real_insn (last_insn) == 0)))
490 emit_insn (gen_nop ());
493 /* Return the rtx-label that corresponds to a LABEL_DECL,
494 creating it if necessary. */
500 if (TREE_CODE (label) != LABEL_DECL)
503 if (!DECL_RTL_SET_P (label))
504 SET_DECL_RTL (label, gen_label_rtx ());
506 return DECL_RTL (label);
509 /* As above, but also put it on the forced-reference list of the
510 function that contains it. */
512 force_label_rtx (label)
515 rtx ref = label_rtx (label);
516 tree function = decl_function_context (label);
522 if (function != current_function_decl
523 && function != inline_function_decl)
524 p = find_function_data (function);
528 p->expr->x_forced_labels = gen_rtx_EXPR_LIST (VOIDmode, ref,
529 p->expr->x_forced_labels);
533 /* Add an unconditional jump to LABEL as the next sequential instruction. */
539 do_pending_stack_adjust ();
540 emit_jump_insn (gen_jump (label));
544 /* Emit code to jump to the address
545 specified by the pointer expression EXP. */
548 expand_computed_goto (exp)
551 rtx x = expand_expr (exp, NULL_RTX, VOIDmode, 0);
553 #ifdef POINTERS_EXTEND_UNSIGNED
554 if (GET_MODE (x) != Pmode)
555 x = convert_memory_address (Pmode, x);
560 if (! cfun->computed_goto_common_label)
562 cfun->computed_goto_common_reg = copy_to_mode_reg (Pmode, x);
563 cfun->computed_goto_common_label = gen_label_rtx ();
564 emit_label (cfun->computed_goto_common_label);
566 do_pending_stack_adjust ();
567 emit_indirect_jump (cfun->computed_goto_common_reg);
569 current_function_has_computed_jump = 1;
573 emit_move_insn (cfun->computed_goto_common_reg, x);
574 emit_jump (cfun->computed_goto_common_label);
578 /* Handle goto statements and the labels that they can go to. */
580 /* Specify the location in the RTL code of a label LABEL,
581 which is a LABEL_DECL tree node.
583 This is used for the kind of label that the user can jump to with a
584 goto statement, and for alternatives of a switch or case statement.
585 RTL labels generated for loops and conditionals don't go through here;
586 they are generated directly at the RTL level, by other functions below.
588 Note that this has nothing to do with defining label *names*.
589 Languages vary in how they do that and what that even means. */
595 struct label_chain *p;
597 do_pending_stack_adjust ();
598 emit_label (label_rtx (label));
599 if (DECL_NAME (label))
600 LABEL_NAME (DECL_RTL (label)) = IDENTIFIER_POINTER (DECL_NAME (label));
602 if (stack_block_stack != 0)
604 p = (struct label_chain *) ggc_alloc (sizeof (struct label_chain));
605 p->next = stack_block_stack->data.block.label_chain;
606 stack_block_stack->data.block.label_chain = p;
611 /* Declare that LABEL (a LABEL_DECL) may be used for nonlocal gotos
612 from nested functions. */
615 declare_nonlocal_label (label)
618 rtx slot = assign_stack_local (Pmode, GET_MODE_SIZE (Pmode), 0);
620 nonlocal_labels = tree_cons (NULL_TREE, label, nonlocal_labels);
621 LABEL_PRESERVE_P (label_rtx (label)) = 1;
622 if (nonlocal_goto_handler_slots == 0)
624 emit_stack_save (SAVE_NONLOCAL,
625 &nonlocal_goto_stack_level,
626 PREV_INSN (tail_recursion_reentry));
628 nonlocal_goto_handler_slots
629 = gen_rtx_EXPR_LIST (VOIDmode, slot, nonlocal_goto_handler_slots);
632 /* Generate RTL code for a `goto' statement with target label LABEL.
633 LABEL should be a LABEL_DECL tree node that was or will later be
634 defined with `expand_label'. */
642 /* Check for a nonlocal goto to a containing function. */
643 context = decl_function_context (label);
644 if (context != 0 && context != current_function_decl)
646 struct function *p = find_function_data (context);
647 rtx label_ref = gen_rtx_LABEL_REF (Pmode, label_rtx (label));
648 rtx handler_slot, static_chain, save_area, insn;
651 /* Find the corresponding handler slot for this label. */
652 handler_slot = p->x_nonlocal_goto_handler_slots;
653 for (link = p->x_nonlocal_labels; TREE_VALUE (link) != label;
654 link = TREE_CHAIN (link))
655 handler_slot = XEXP (handler_slot, 1);
656 handler_slot = XEXP (handler_slot, 0);
658 p->has_nonlocal_label = 1;
659 current_function_has_nonlocal_goto = 1;
660 LABEL_REF_NONLOCAL_P (label_ref) = 1;
662 /* Copy the rtl for the slots so that they won't be shared in
663 case the virtual stack vars register gets instantiated differently
664 in the parent than in the child. */
666 static_chain = copy_to_reg (lookup_static_chain (label));
668 /* Get addr of containing function's current nonlocal goto handler,
669 which will do any cleanups and then jump to the label. */
670 handler_slot = copy_to_reg (replace_rtx (copy_rtx (handler_slot),
671 virtual_stack_vars_rtx,
674 /* Get addr of containing function's nonlocal save area. */
675 save_area = p->x_nonlocal_goto_stack_level;
677 save_area = replace_rtx (copy_rtx (save_area),
678 virtual_stack_vars_rtx, static_chain);
680 #if HAVE_nonlocal_goto
681 if (HAVE_nonlocal_goto)
682 emit_insn (gen_nonlocal_goto (static_chain, handler_slot,
683 save_area, label_ref));
687 /* Restore frame pointer for containing function.
688 This sets the actual hard register used for the frame pointer
689 to the location of the function's incoming static chain info.
690 The non-local goto handler will then adjust it to contain the
691 proper value and reload the argument pointer, if needed. */
692 emit_move_insn (hard_frame_pointer_rtx, static_chain);
693 emit_stack_restore (SAVE_NONLOCAL, save_area, NULL_RTX);
695 /* USE of hard_frame_pointer_rtx added for consistency;
696 not clear if really needed. */
697 emit_insn (gen_rtx_USE (VOIDmode, hard_frame_pointer_rtx));
698 emit_insn (gen_rtx_USE (VOIDmode, stack_pointer_rtx));
699 emit_indirect_jump (handler_slot);
702 /* Search backwards to the jump insn and mark it as a
704 for (insn = get_last_insn (); insn; insn = PREV_INSN (insn))
706 if (GET_CODE (insn) == JUMP_INSN)
708 REG_NOTES (insn) = alloc_EXPR_LIST (REG_NON_LOCAL_GOTO,
709 const0_rtx, REG_NOTES (insn));
712 else if (GET_CODE (insn) == CALL_INSN)
717 expand_goto_internal (label, label_rtx (label), NULL_RTX);
720 /* Generate RTL code for a `goto' statement with target label BODY.
721 LABEL should be a LABEL_REF.
722 LAST_INSN, if non-0, is the rtx we should consider as the last
723 insn emitted (for the purposes of cleaning up a return). */
726 expand_goto_internal (body, label, last_insn)
731 struct nesting *block;
734 if (GET_CODE (label) != CODE_LABEL)
737 /* If label has already been defined, we can tell now
738 whether and how we must alter the stack level. */
740 if (PREV_INSN (label) != 0)
742 /* Find the innermost pending block that contains the label.
743 (Check containment by comparing insn-uids.)
744 Then restore the outermost stack level within that block,
745 and do cleanups of all blocks contained in it. */
746 for (block = block_stack; block; block = block->next)
748 if (INSN_UID (block->data.block.first_insn) < INSN_UID (label))
750 if (block->data.block.stack_level != 0)
751 stack_level = block->data.block.stack_level;
752 /* Execute the cleanups for blocks we are exiting. */
753 if (block->data.block.cleanups != 0)
755 expand_cleanups (block->data.block.cleanups, 1, 1);
756 do_pending_stack_adjust ();
762 /* Ensure stack adjust isn't done by emit_jump, as this
763 would clobber the stack pointer. This one should be
764 deleted as dead by flow. */
765 clear_pending_stack_adjust ();
766 do_pending_stack_adjust ();
768 /* Don't do this adjust if it's to the end label and this function
769 is to return with a depressed stack pointer. */
770 if (label == return_label
771 && (((TREE_CODE (TREE_TYPE (current_function_decl))
773 && (TYPE_RETURNS_STACK_DEPRESSED
774 (TREE_TYPE (current_function_decl))))))
777 emit_stack_restore (SAVE_BLOCK, stack_level, NULL_RTX);
780 if (body != 0 && DECL_TOO_LATE (body))
781 error ("jump to `%s' invalidly jumps into binding contour",
782 IDENTIFIER_POINTER (DECL_NAME (body)));
784 /* Label not yet defined: may need to put this goto
785 on the fixup list. */
786 else if (! expand_fixup (body, label, last_insn))
788 /* No fixup needed. Record that the label is the target
789 of at least one goto that has no fixup. */
791 TREE_ADDRESSABLE (body) = 1;
797 /* Generate if necessary a fixup for a goto
798 whose target label in tree structure (if any) is TREE_LABEL
799 and whose target in rtl is RTL_LABEL.
801 If LAST_INSN is nonzero, we pretend that the jump appears
802 after insn LAST_INSN instead of at the current point in the insn stream.
804 The fixup will be used later to insert insns just before the goto.
805 Those insns will restore the stack level as appropriate for the
806 target label, and will (in the case of C++) also invoke any object
807 destructors which have to be invoked when we exit the scopes which
808 are exited by the goto.
810 Value is nonzero if a fixup is made. */
813 expand_fixup (tree_label, rtl_label, last_insn)
818 struct nesting *block, *end_block;
820 /* See if we can recognize which block the label will be output in.
821 This is possible in some very common cases.
822 If we succeed, set END_BLOCK to that block.
823 Otherwise, set it to 0. */
826 && (rtl_label == cond_stack->data.cond.endif_label
827 || rtl_label == cond_stack->data.cond.next_label))
828 end_block = cond_stack;
829 /* If we are in a loop, recognize certain labels which
830 are likely targets. This reduces the number of fixups
831 we need to create. */
833 && (rtl_label == loop_stack->data.loop.start_label
834 || rtl_label == loop_stack->data.loop.end_label
835 || rtl_label == loop_stack->data.loop.continue_label))
836 end_block = loop_stack;
840 /* Now set END_BLOCK to the binding level to which we will return. */
844 struct nesting *next_block = end_block->all;
847 /* First see if the END_BLOCK is inside the innermost binding level.
848 If so, then no cleanups or stack levels are relevant. */
849 while (next_block && next_block != block)
850 next_block = next_block->all;
855 /* Otherwise, set END_BLOCK to the innermost binding level
856 which is outside the relevant control-structure nesting. */
857 next_block = block_stack->next;
858 for (block = block_stack; block != end_block; block = block->all)
859 if (block == next_block)
860 next_block = next_block->next;
861 end_block = next_block;
864 /* Does any containing block have a stack level or cleanups?
865 If not, no fixup is needed, and that is the normal case
866 (the only case, for standard C). */
867 for (block = block_stack; block != end_block; block = block->next)
868 if (block->data.block.stack_level != 0
869 || block->data.block.cleanups != 0)
872 if (block != end_block)
874 /* Ok, a fixup is needed. Add a fixup to the list of such. */
875 struct goto_fixup *fixup
876 = (struct goto_fixup *) ggc_alloc (sizeof (struct goto_fixup));
877 /* In case an old stack level is restored, make sure that comes
878 after any pending stack adjust. */
879 /* ?? If the fixup isn't to come at the present position,
880 doing the stack adjust here isn't useful. Doing it with our
881 settings at that location isn't useful either. Let's hope
884 do_pending_stack_adjust ();
885 fixup->target = tree_label;
886 fixup->target_rtl = rtl_label;
888 /* Create a BLOCK node and a corresponding matched set of
889 NOTE_INSN_BLOCK_BEG and NOTE_INSN_BLOCK_END notes at
890 this point. The notes will encapsulate any and all fixup
891 code which we might later insert at this point in the insn
892 stream. Also, the BLOCK node will be the parent (i.e. the
893 `SUPERBLOCK') of any other BLOCK nodes which we might create
894 later on when we are expanding the fixup code.
896 Note that optimization passes (including expand_end_loop)
897 might move the *_BLOCK notes away, so we use a NOTE_INSN_DELETED
901 rtx original_before_jump
902 = last_insn ? last_insn : get_last_insn ();
907 block = make_node (BLOCK);
908 TREE_USED (block) = 1;
910 if (!cfun->x_whole_function_mode_p)
911 (*lang_hooks.decls.insert_block) (block);
915 = BLOCK_CHAIN (DECL_INITIAL (current_function_decl));
916 BLOCK_CHAIN (DECL_INITIAL (current_function_decl))
921 start = emit_note (NOTE_INSN_BLOCK_BEG);
922 if (cfun->x_whole_function_mode_p)
923 NOTE_BLOCK (start) = block;
924 fixup->before_jump = emit_note (NOTE_INSN_DELETED);
925 end = emit_note (NOTE_INSN_BLOCK_END);
926 if (cfun->x_whole_function_mode_p)
927 NOTE_BLOCK (end) = block;
928 fixup->context = block;
930 emit_insn_after (start, original_before_jump);
933 fixup->block_start_count = current_block_start_count;
934 fixup->stack_level = 0;
935 fixup->cleanup_list_list
936 = ((block->data.block.outer_cleanups
937 || block->data.block.cleanups)
938 ? tree_cons (NULL_TREE, block->data.block.cleanups,
939 block->data.block.outer_cleanups)
941 fixup->next = goto_fixup_chain;
942 goto_fixup_chain = fixup;
948 /* Expand any needed fixups in the outputmost binding level of the
949 function. FIRST_INSN is the first insn in the function. */
952 expand_fixups (first_insn)
955 fixup_gotos (NULL, NULL_RTX, NULL_TREE, first_insn, 0);
958 /* When exiting a binding contour, process all pending gotos requiring fixups.
959 THISBLOCK is the structure that describes the block being exited.
960 STACK_LEVEL is the rtx for the stack level to restore exiting this contour.
961 CLEANUP_LIST is a list of expressions to evaluate on exiting this contour.
962 FIRST_INSN is the insn that began this contour.
964 Gotos that jump out of this contour must restore the
965 stack level and do the cleanups before actually jumping.
967 DONT_JUMP_IN positive means report error if there is a jump into this
968 contour from before the beginning of the contour. This is also done if
969 STACK_LEVEL is nonzero unless DONT_JUMP_IN is negative. */
972 fixup_gotos (thisblock, stack_level, cleanup_list, first_insn, dont_jump_in)
973 struct nesting *thisblock;
979 struct goto_fixup *f, *prev;
981 /* F is the fixup we are considering; PREV is the previous one. */
982 /* We run this loop in two passes so that cleanups of exited blocks
983 are run first, and blocks that are exited are marked so
986 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
988 /* Test for a fixup that is inactive because it is already handled. */
989 if (f->before_jump == 0)
991 /* Delete inactive fixup from the chain, if that is easy to do. */
993 prev->next = f->next;
995 /* Has this fixup's target label been defined?
996 If so, we can finalize it. */
997 else if (PREV_INSN (f->target_rtl) != 0)
1001 /* If this fixup jumped into this contour from before the beginning
1002 of this contour, report an error. This code used to use
1003 the first non-label insn after f->target_rtl, but that's
1004 wrong since such can be added, by things like put_var_into_stack
1005 and have INSN_UIDs that are out of the range of the block. */
1006 /* ??? Bug: this does not detect jumping in through intermediate
1007 blocks that have stack levels or cleanups.
1008 It detects only a problem with the innermost block
1009 around the label. */
1011 && (dont_jump_in > 0 || (dont_jump_in == 0 && stack_level)
1013 && INSN_UID (first_insn) < INSN_UID (f->target_rtl)
1014 && INSN_UID (first_insn) > INSN_UID (f->before_jump)
1015 && ! DECL_ERROR_ISSUED (f->target))
1017 error_with_decl (f->target,
1018 "label `%s' used before containing binding contour");
1019 /* Prevent multiple errors for one label. */
1020 DECL_ERROR_ISSUED (f->target) = 1;
1023 /* We will expand the cleanups into a sequence of their own and
1024 then later on we will attach this new sequence to the insn
1025 stream just ahead of the actual jump insn. */
1029 /* Temporarily restore the lexical context where we will
1030 logically be inserting the fixup code. We do this for the
1031 sake of getting the debugging information right. */
1033 (*lang_hooks.decls.pushlevel) (0);
1034 (*lang_hooks.decls.set_block) (f->context);
1036 /* Expand the cleanups for blocks this jump exits. */
1037 if (f->cleanup_list_list)
1040 for (lists = f->cleanup_list_list; lists; lists = TREE_CHAIN (lists))
1041 /* Marked elements correspond to blocks that have been closed.
1042 Do their cleanups. */
1043 if (TREE_ADDRESSABLE (lists)
1044 && TREE_VALUE (lists) != 0)
1046 expand_cleanups (TREE_VALUE (lists), 1, 1);
1047 /* Pop any pushes done in the cleanups,
1048 in case function is about to return. */
1049 do_pending_stack_adjust ();
1053 /* Restore stack level for the biggest contour that this
1054 jump jumps out of. */
1056 && ! (f->target_rtl == return_label
1057 && ((TREE_CODE (TREE_TYPE (current_function_decl))
1059 && (TYPE_RETURNS_STACK_DEPRESSED
1060 (TREE_TYPE (current_function_decl))))))
1061 emit_stack_restore (SAVE_BLOCK, f->stack_level, f->before_jump);
1063 /* Finish up the sequence containing the insns which implement the
1064 necessary cleanups, and then attach that whole sequence to the
1065 insn stream just ahead of the actual jump insn. Attaching it
1066 at that point insures that any cleanups which are in fact
1067 implicit C++ object destructions (which must be executed upon
1068 leaving the block) appear (to the debugger) to be taking place
1069 in an area of the generated code where the object(s) being
1070 destructed are still "in scope". */
1072 cleanup_insns = get_insns ();
1073 (*lang_hooks.decls.poplevel) (1, 0, 0);
1076 emit_insn_after (cleanup_insns, f->before_jump);
1082 /* For any still-undefined labels, do the cleanups for this block now.
1083 We must do this now since items in the cleanup list may go out
1084 of scope when the block ends. */
1085 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
1086 if (f->before_jump != 0
1087 && PREV_INSN (f->target_rtl) == 0
1088 /* Label has still not appeared. If we are exiting a block with
1089 a stack level to restore, that started before the fixup,
1090 mark this stack level as needing restoration
1091 when the fixup is later finalized. */
1093 /* Note: if THISBLOCK == 0 and we have a label that hasn't appeared, it
1094 means the label is undefined. That's erroneous, but possible. */
1095 && (thisblock->data.block.block_start_count
1096 <= f->block_start_count))
1098 tree lists = f->cleanup_list_list;
1101 for (; lists; lists = TREE_CHAIN (lists))
1102 /* If the following elt. corresponds to our containing block
1103 then the elt. must be for this block. */
1104 if (TREE_CHAIN (lists) == thisblock->data.block.outer_cleanups)
1107 (*lang_hooks.decls.pushlevel) (0);
1108 (*lang_hooks.decls.set_block) (f->context);
1109 expand_cleanups (TREE_VALUE (lists), 1, 1);
1110 do_pending_stack_adjust ();
1111 cleanup_insns = get_insns ();
1112 (*lang_hooks.decls.poplevel) (1, 0, 0);
1114 if (cleanup_insns != 0)
1116 = emit_insn_after (cleanup_insns, f->before_jump);
1118 f->cleanup_list_list = TREE_CHAIN (lists);
1122 f->stack_level = stack_level;
1126 /* Return the number of times character C occurs in string S. */
1128 n_occurrences (c, s)
1138 /* Generate RTL for an asm statement (explicit assembler code).
1139 STRING is a STRING_CST node containing the assembler code text,
1140 or an ADDR_EXPR containing a STRING_CST. VOL nonzero means the
1141 insn is volatile; don't optimize it. */
1144 expand_asm (string, vol)
1150 if (TREE_CODE (string) == ADDR_EXPR)
1151 string = TREE_OPERAND (string, 0);
1153 body = gen_rtx_ASM_INPUT (VOIDmode, TREE_STRING_POINTER (string));
1155 MEM_VOLATILE_P (body) = vol;
1162 /* Parse the output constraint pointed to by *CONSTRAINT_P. It is the
1163 OPERAND_NUMth output operand, indexed from zero. There are NINPUTS
1164 inputs and NOUTPUTS outputs to this extended-asm. Upon return,
1165 *ALLOWS_MEM will be TRUE iff the constraint allows the use of a
1166 memory operand. Similarly, *ALLOWS_REG will be TRUE iff the
1167 constraint allows the use of a register operand. And, *IS_INOUT
1168 will be true if the operand is read-write, i.e., if it is used as
1169 an input as well as an output. If *CONSTRAINT_P is not in
1170 canonical form, it will be made canonical. (Note that `+' will be
1171 replaced with `=' as part of this process.)
1173 Returns TRUE if all went well; FALSE if an error occurred. */
1176 parse_output_constraint (constraint_p, operand_num, ninputs, noutputs,
1177 allows_mem, allows_reg, is_inout)
1178 const char **constraint_p;
1186 const char *constraint = *constraint_p;
1189 /* Assume the constraint doesn't allow the use of either a register
1191 *allows_mem = false;
1192 *allows_reg = false;
1194 /* Allow the `=' or `+' to not be at the beginning of the string,
1195 since it wasn't explicitly documented that way, and there is a
1196 large body of code that puts it last. Swap the character to
1197 the front, so as not to uglify any place else. */
1198 p = strchr (constraint, '=');
1200 p = strchr (constraint, '+');
1202 /* If the string doesn't contain an `=', issue an error
1206 error ("output operand constraint lacks `='");
1210 /* If the constraint begins with `+', then the operand is both read
1211 from and written to. */
1212 *is_inout = (*p == '+');
1214 /* Canonicalize the output constraint so that it begins with `='. */
1215 if (p != constraint || is_inout)
1218 size_t c_len = strlen (constraint);
1220 if (p != constraint)
1221 warning ("output constraint `%c' for operand %d is not at the beginning",
1224 /* Make a copy of the constraint. */
1225 buf = alloca (c_len + 1);
1226 strcpy (buf, constraint);
1227 /* Swap the first character and the `=' or `+'. */
1228 buf[p - constraint] = buf[0];
1229 /* Make sure the first character is an `='. (Until we do this,
1230 it might be a `+'.) */
1232 /* Replace the constraint with the canonicalized string. */
1233 *constraint_p = ggc_alloc_string (buf, c_len);
1234 constraint = *constraint_p;
1237 /* Loop through the constraint string. */
1238 for (p = constraint + 1; *p; p += CONSTRAINT_LEN (*p, p))
1243 error ("operand constraint contains incorrectly positioned '+' or '='");
1247 if (operand_num + 1 == ninputs + noutputs)
1249 error ("`%%' constraint used with last operand");
1254 case 'V': case 'm': case 'o':
1258 case '?': case '!': case '*': case '&': case '#':
1259 case 'E': case 'F': case 'G': case 'H':
1260 case 's': case 'i': case 'n':
1261 case 'I': case 'J': case 'K': case 'L': case 'M':
1262 case 'N': case 'O': case 'P': case ',':
1265 case '0': case '1': case '2': case '3': case '4':
1266 case '5': case '6': case '7': case '8': case '9':
1268 error ("matching constraint not valid in output operand");
1272 /* ??? Before flow, auto inc/dec insns are not supposed to exist,
1273 excepting those that expand_call created. So match memory
1290 if (REG_CLASS_FROM_CONSTRAINT (*p, p) != NO_REGS)
1292 #ifdef EXTRA_CONSTRAINT_STR
1293 else if (EXTRA_ADDRESS_CONSTRAINT (*p, p))
1295 else if (EXTRA_MEMORY_CONSTRAINT (*p, p))
1299 /* Otherwise we can't assume anything about the nature of
1300 the constraint except that it isn't purely registers.
1301 Treat it like "g" and hope for the best. */
1312 /* Similar, but for input constraints. */
1315 parse_input_constraint (constraint_p, input_num, ninputs, noutputs, ninout,
1316 constraints, allows_mem, allows_reg)
1317 const char **constraint_p;
1322 const char * const * constraints;
1326 const char *constraint = *constraint_p;
1327 const char *orig_constraint = constraint;
1328 size_t c_len = strlen (constraint);
1331 /* Assume the constraint doesn't allow the use of either
1332 a register or memory. */
1333 *allows_mem = false;
1334 *allows_reg = false;
1336 /* Make sure constraint has neither `=', `+', nor '&'. */
1338 for (j = 0; j < c_len; j += CONSTRAINT_LEN (constraint[j], constraint+j))
1339 switch (constraint[j])
1341 case '+': case '=': case '&':
1342 if (constraint == orig_constraint)
1344 error ("input operand constraint contains `%c'", constraint[j]);
1350 if (constraint == orig_constraint
1351 && input_num + 1 == ninputs - ninout)
1353 error ("`%%' constraint used with last operand");
1358 case 'V': case 'm': case 'o':
1363 case '?': case '!': case '*': case '#':
1364 case 'E': case 'F': case 'G': case 'H':
1365 case 's': case 'i': case 'n':
1366 case 'I': case 'J': case 'K': case 'L': case 'M':
1367 case 'N': case 'O': case 'P': case ',':
1370 /* Whether or not a numeric constraint allows a register is
1371 decided by the matching constraint, and so there is no need
1372 to do anything special with them. We must handle them in
1373 the default case, so that we don't unnecessarily force
1374 operands to memory. */
1375 case '0': case '1': case '2': case '3': case '4':
1376 case '5': case '6': case '7': case '8': case '9':
1379 unsigned long match;
1381 match = strtoul (constraint + j, &end, 10);
1382 if (match >= (unsigned long) noutputs)
1384 error ("matching constraint references invalid operand number");
1388 /* Try and find the real constraint for this dup. Only do this
1389 if the matching constraint is the only alternative. */
1391 && (j == 0 || (j == 1 && constraint[0] == '%')))
1393 constraint = constraints[match];
1394 *constraint_p = constraint;
1395 c_len = strlen (constraint);
1397 /* ??? At the end of the loop, we will skip the first part of
1398 the matched constraint. This assumes not only that the
1399 other constraint is an output constraint, but also that
1400 the '=' or '+' come first. */
1404 j = end - constraint;
1405 /* Anticipate increment at end of loop. */
1420 if (! ISALPHA (constraint[j]))
1422 error ("invalid punctuation `%c' in constraint", constraint[j]);
1425 if (REG_CLASS_FROM_CONSTRAINT (constraint[j], constraint + j)
1428 #ifdef EXTRA_CONSTRAINT_STR
1429 else if (EXTRA_ADDRESS_CONSTRAINT (constraint[j], constraint + j))
1431 else if (EXTRA_MEMORY_CONSTRAINT (constraint[j], constraint + j))
1435 /* Otherwise we can't assume anything about the nature of
1436 the constraint except that it isn't purely registers.
1437 Treat it like "g" and hope for the best. */
1448 /* Check for overlap between registers marked in CLOBBERED_REGS and
1449 anything inappropriate in DECL. Emit error and return TRUE for error,
1453 decl_conflicts_with_clobbers_p (decl, clobbered_regs)
1455 const HARD_REG_SET clobbered_regs;
1457 /* Conflicts between asm-declared register variables and the clobber
1458 list are not allowed. */
1459 if ((TREE_CODE (decl) == VAR_DECL || TREE_CODE (decl) == PARM_DECL)
1460 && DECL_REGISTER (decl)
1461 && REG_P (DECL_RTL (decl))
1462 && REGNO (DECL_RTL (decl)) < FIRST_PSEUDO_REGISTER)
1464 rtx reg = DECL_RTL (decl);
1467 for (regno = REGNO (reg);
1468 regno < (REGNO (reg)
1469 + HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg)));
1471 if (TEST_HARD_REG_BIT (clobbered_regs, regno))
1473 error ("asm-specifier for variable `%s' conflicts with asm clobber list",
1474 IDENTIFIER_POINTER (DECL_NAME (decl)));
1476 /* Reset registerness to stop multiple errors emitted for a
1478 DECL_REGISTER (decl) = 0;
1485 /* Generate RTL for an asm statement with arguments.
1486 STRING is the instruction template.
1487 OUTPUTS is a list of output arguments (lvalues); INPUTS a list of inputs.
1488 Each output or input has an expression in the TREE_VALUE and
1489 and a tree list in TREE_PURPOSE which in turn contains a constraint
1490 name in TREE_VALUE (or NULL_TREE) and a constraint string
1492 CLOBBERS is a list of STRING_CST nodes each naming a hard register
1493 that is clobbered by this insn.
1495 Not all kinds of lvalue that may appear in OUTPUTS can be stored directly.
1496 Some elements of OUTPUTS may be replaced with trees representing temporary
1497 values. The caller should copy those temporary values to the originally
1500 VOL nonzero means the insn is volatile; don't optimize it. */
1503 expand_asm_operands (string, outputs, inputs, clobbers, vol, filename, line)
1504 tree string, outputs, inputs, clobbers;
1506 const char *filename;
1509 rtvec argvec, constraintvec;
1511 int ninputs = list_length (inputs);
1512 int noutputs = list_length (outputs);
1515 HARD_REG_SET clobbered_regs;
1516 int clobber_conflict_found = 0;
1520 /* Vector of RTX's of evaluated output operands. */
1521 rtx *output_rtx = (rtx *) alloca (noutputs * sizeof (rtx));
1522 int *inout_opnum = (int *) alloca (noutputs * sizeof (int));
1523 rtx *real_output_rtx = (rtx *) alloca (noutputs * sizeof (rtx));
1524 enum machine_mode *inout_mode
1525 = (enum machine_mode *) alloca (noutputs * sizeof (enum machine_mode));
1526 const char **constraints
1527 = (const char **) alloca ((noutputs + ninputs) * sizeof (const char *));
1528 int old_generating_concat_p = generating_concat_p;
1530 /* An ASM with no outputs needs to be treated as volatile, for now. */
1534 if (! check_operand_nalternatives (outputs, inputs))
1537 if (! check_unique_operand_names (outputs, inputs))
1540 string = resolve_asm_operand_names (string, outputs, inputs);
1542 /* Collect constraints. */
1544 for (t = outputs; t ; t = TREE_CHAIN (t), i++)
1545 constraints[i] = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
1546 for (t = inputs; t ; t = TREE_CHAIN (t), i++)
1547 constraints[i] = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
1549 #ifdef MD_ASM_CLOBBERS
1550 /* Sometimes we wish to automatically clobber registers across an asm.
1551 Case in point is when the i386 backend moved from cc0 to a hard reg --
1552 maintaining source-level compatibility means automatically clobbering
1553 the flags register. */
1554 MD_ASM_CLOBBERS (clobbers);
1557 /* Count the number of meaningful clobbered registers, ignoring what
1558 we would ignore later. */
1560 CLEAR_HARD_REG_SET (clobbered_regs);
1561 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1563 const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1565 i = decode_reg_name (regname);
1566 if (i >= 0 || i == -4)
1569 error ("unknown register name `%s' in `asm'", regname);
1571 /* Mark clobbered registers. */
1574 /* Clobbering the PIC register is an error */
1575 if (i == (int) PIC_OFFSET_TABLE_REGNUM)
1577 error ("PIC register `%s' clobbered in `asm'", regname);
1581 SET_HARD_REG_BIT (clobbered_regs, i);
1587 /* First pass over inputs and outputs checks validity and sets
1588 mark_addressable if needed. */
1591 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1593 tree val = TREE_VALUE (tail);
1594 tree type = TREE_TYPE (val);
1595 const char *constraint;
1600 /* If there's an erroneous arg, emit no insn. */
1601 if (type == error_mark_node)
1604 /* Try to parse the output constraint. If that fails, there's
1605 no point in going further. */
1606 constraint = constraints[i];
1607 if (!parse_output_constraint (&constraint, i, ninputs, noutputs,
1608 &allows_mem, &allows_reg, &is_inout))
1615 && GET_CODE (DECL_RTL (val)) == REG
1616 && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type))))
1617 (*lang_hooks.mark_addressable) (val);
1624 if (ninputs + noutputs > MAX_RECOG_OPERANDS)
1626 error ("more than %d operands in `asm'", MAX_RECOG_OPERANDS);
1630 for (i = 0, tail = inputs; tail; i++, tail = TREE_CHAIN (tail))
1632 bool allows_reg, allows_mem;
1633 const char *constraint;
1635 /* If there's an erroneous arg, emit no insn, because the ASM_INPUT
1636 would get VOIDmode and that could cause a crash in reload. */
1637 if (TREE_TYPE (TREE_VALUE (tail)) == error_mark_node)
1640 constraint = constraints[i + noutputs];
1641 if (! parse_input_constraint (&constraint, i, ninputs, noutputs, ninout,
1642 constraints, &allows_mem, &allows_reg))
1645 if (! allows_reg && allows_mem)
1646 (*lang_hooks.mark_addressable) (TREE_VALUE (tail));
1649 /* Second pass evaluates arguments. */
1652 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1654 tree val = TREE_VALUE (tail);
1655 tree type = TREE_TYPE (val);
1661 if (!parse_output_constraint (&constraints[i], i, ninputs,
1662 noutputs, &allows_mem, &allows_reg,
1666 /* If an output operand is not a decl or indirect ref and our constraint
1667 allows a register, make a temporary to act as an intermediate.
1668 Make the asm insn write into that, then our caller will copy it to
1669 the real output operand. Likewise for promoted variables. */
1671 generating_concat_p = 0;
1673 real_output_rtx[i] = NULL_RTX;
1674 if ((TREE_CODE (val) == INDIRECT_REF
1677 && (allows_mem || GET_CODE (DECL_RTL (val)) == REG)
1678 && ! (GET_CODE (DECL_RTL (val)) == REG
1679 && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type)))
1683 op = expand_expr (val, NULL_RTX, VOIDmode, EXPAND_WRITE);
1684 if (GET_CODE (op) == MEM)
1685 op = validize_mem (op);
1687 if (! allows_reg && GET_CODE (op) != MEM)
1688 error ("output number %d not directly addressable", i);
1689 if ((! allows_mem && GET_CODE (op) == MEM)
1690 || GET_CODE (op) == CONCAT)
1692 real_output_rtx[i] = protect_from_queue (op, 1);
1693 op = gen_reg_rtx (GET_MODE (op));
1695 emit_move_insn (op, real_output_rtx[i]);
1700 op = assign_temp (type, 0, 0, 1);
1701 op = validize_mem (op);
1702 TREE_VALUE (tail) = make_tree (type, op);
1706 generating_concat_p = old_generating_concat_p;
1710 inout_mode[ninout] = TYPE_MODE (type);
1711 inout_opnum[ninout++] = i;
1714 if (decl_conflicts_with_clobbers_p (val, clobbered_regs))
1715 clobber_conflict_found = 1;
1718 /* Make vectors for the expression-rtx, constraint strings,
1719 and named operands. */
1721 argvec = rtvec_alloc (ninputs);
1722 constraintvec = rtvec_alloc (ninputs);
1724 body = gen_rtx_ASM_OPERANDS ((noutputs == 0 ? VOIDmode
1725 : GET_MODE (output_rtx[0])),
1726 TREE_STRING_POINTER (string),
1727 empty_string, 0, argvec, constraintvec,
1730 MEM_VOLATILE_P (body) = vol;
1732 /* Eval the inputs and put them into ARGVEC.
1733 Put their constraints into ASM_INPUTs and store in CONSTRAINTS. */
1735 for (i = 0, tail = inputs; tail; tail = TREE_CHAIN (tail), ++i)
1737 bool allows_reg, allows_mem;
1738 const char *constraint;
1742 constraint = constraints[i + noutputs];
1743 if (! parse_input_constraint (&constraint, i, ninputs, noutputs, ninout,
1744 constraints, &allows_mem, &allows_reg))
1747 generating_concat_p = 0;
1749 val = TREE_VALUE (tail);
1750 type = TREE_TYPE (val);
1751 op = expand_expr (val, NULL_RTX, VOIDmode,
1752 (allows_mem && !allows_reg
1753 ? EXPAND_MEMORY : EXPAND_NORMAL));
1755 /* Never pass a CONCAT to an ASM. */
1756 if (GET_CODE (op) == CONCAT)
1757 op = force_reg (GET_MODE (op), op);
1758 else if (GET_CODE (op) == MEM)
1759 op = validize_mem (op);
1761 if (asm_operand_ok (op, constraint) <= 0)
1764 op = force_reg (TYPE_MODE (type), op);
1765 else if (!allows_mem)
1766 warning ("asm operand %d probably doesn't match constraints",
1768 else if (GET_CODE (op) == MEM)
1770 /* We won't recognize either volatile memory or memory
1771 with a queued address as available a memory_operand
1772 at this point. Ignore it: clearly this *is* a memory. */
1776 warning ("use of memory input without lvalue in "
1777 "asm operand %d is deprecated", i + noutputs);
1779 if (CONSTANT_P (op))
1781 op = force_const_mem (TYPE_MODE (type), op);
1782 op = validize_mem (op);
1784 else if (GET_CODE (op) == REG
1785 || GET_CODE (op) == SUBREG
1786 || GET_CODE (op) == ADDRESSOF
1787 || GET_CODE (op) == CONCAT)
1789 tree qual_type = build_qualified_type (type,
1791 | TYPE_QUAL_CONST));
1792 rtx memloc = assign_temp (qual_type, 1, 1, 1);
1793 memloc = validize_mem (memloc);
1794 emit_move_insn (memloc, op);
1800 generating_concat_p = old_generating_concat_p;
1801 ASM_OPERANDS_INPUT (body, i) = op;
1803 ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, i)
1804 = gen_rtx_ASM_INPUT (TYPE_MODE (type), constraints[i + noutputs]);
1806 if (decl_conflicts_with_clobbers_p (val, clobbered_regs))
1807 clobber_conflict_found = 1;
1810 /* Protect all the operands from the queue now that they have all been
1813 generating_concat_p = 0;
1815 for (i = 0; i < ninputs - ninout; i++)
1816 ASM_OPERANDS_INPUT (body, i)
1817 = protect_from_queue (ASM_OPERANDS_INPUT (body, i), 0);
1819 for (i = 0; i < noutputs; i++)
1820 output_rtx[i] = protect_from_queue (output_rtx[i], 1);
1822 /* For in-out operands, copy output rtx to input rtx. */
1823 for (i = 0; i < ninout; i++)
1825 int j = inout_opnum[i];
1828 ASM_OPERANDS_INPUT (body, ninputs - ninout + i)
1831 sprintf (buffer, "%d", j);
1832 ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, ninputs - ninout + i)
1833 = gen_rtx_ASM_INPUT (inout_mode[i], ggc_strdup (buffer));
1836 generating_concat_p = old_generating_concat_p;
1838 /* Now, for each output, construct an rtx
1839 (set OUTPUT (asm_operands INSN OUTPUTCONSTRAINT OUTPUTNUMBER
1840 ARGVEC CONSTRAINTS OPNAMES))
1841 If there is more than one, put them inside a PARALLEL. */
1843 if (noutputs == 1 && nclobbers == 0)
1845 ASM_OPERANDS_OUTPUT_CONSTRAINT (body) = constraints[0];
1846 emit_insn (gen_rtx_SET (VOIDmode, output_rtx[0], body));
1849 else if (noutputs == 0 && nclobbers == 0)
1851 /* No output operands: put in a raw ASM_OPERANDS rtx. */
1863 body = gen_rtx_PARALLEL (VOIDmode, rtvec_alloc (num + nclobbers));
1865 /* For each output operand, store a SET. */
1866 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1868 XVECEXP (body, 0, i)
1869 = gen_rtx_SET (VOIDmode,
1871 gen_rtx_ASM_OPERANDS
1872 (GET_MODE (output_rtx[i]),
1873 TREE_STRING_POINTER (string),
1874 constraints[i], i, argvec, constraintvec,
1877 MEM_VOLATILE_P (SET_SRC (XVECEXP (body, 0, i))) = vol;
1880 /* If there are no outputs (but there are some clobbers)
1881 store the bare ASM_OPERANDS into the PARALLEL. */
1884 XVECEXP (body, 0, i++) = obody;
1886 /* Store (clobber REG) for each clobbered register specified. */
1888 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1890 const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1891 int j = decode_reg_name (regname);
1896 if (j == -3) /* `cc', which is not a register */
1899 if (j == -4) /* `memory', don't cache memory across asm */
1901 XVECEXP (body, 0, i++)
1902 = gen_rtx_CLOBBER (VOIDmode,
1905 gen_rtx_SCRATCH (VOIDmode)));
1909 /* Ignore unknown register, error already signaled. */
1913 /* Use QImode since that's guaranteed to clobber just one reg. */
1914 clobbered_reg = gen_rtx_REG (QImode, j);
1916 /* Do sanity check for overlap between clobbers and respectively
1917 input and outputs that hasn't been handled. Such overlap
1918 should have been detected and reported above. */
1919 if (!clobber_conflict_found)
1923 /* We test the old body (obody) contents to avoid tripping
1924 over the under-construction body. */
1925 for (opno = 0; opno < noutputs; opno++)
1926 if (reg_overlap_mentioned_p (clobbered_reg, output_rtx[opno]))
1927 internal_error ("asm clobber conflict with output operand");
1929 for (opno = 0; opno < ninputs - ninout; opno++)
1930 if (reg_overlap_mentioned_p (clobbered_reg,
1931 ASM_OPERANDS_INPUT (obody, opno)))
1932 internal_error ("asm clobber conflict with input operand");
1935 XVECEXP (body, 0, i++)
1936 = gen_rtx_CLOBBER (VOIDmode, clobbered_reg);
1942 /* For any outputs that needed reloading into registers, spill them
1943 back to where they belong. */
1944 for (i = 0; i < noutputs; ++i)
1945 if (real_output_rtx[i])
1946 emit_move_insn (real_output_rtx[i], output_rtx[i]);
1951 /* A subroutine of expand_asm_operands. Check that all operands have
1952 the same number of alternatives. Return true if so. */
1955 check_operand_nalternatives (outputs, inputs)
1956 tree outputs, inputs;
1958 if (outputs || inputs)
1960 tree tmp = TREE_PURPOSE (outputs ? outputs : inputs);
1962 = n_occurrences (',', TREE_STRING_POINTER (TREE_VALUE (tmp)));
1965 if (nalternatives + 1 > MAX_RECOG_ALTERNATIVES)
1967 error ("too many alternatives in `asm'");
1974 const char *constraint
1975 = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tmp)));
1977 if (n_occurrences (',', constraint) != nalternatives)
1979 error ("operand constraints for `asm' differ in number of alternatives");
1983 if (TREE_CHAIN (tmp))
1984 tmp = TREE_CHAIN (tmp);
1986 tmp = next, next = 0;
1993 /* A subroutine of expand_asm_operands. Check that all operand names
1994 are unique. Return true if so. We rely on the fact that these names
1995 are identifiers, and so have been canonicalized by get_identifier,
1996 so all we need are pointer comparisons. */
1999 check_unique_operand_names (outputs, inputs)
2000 tree outputs, inputs;
2004 for (i = outputs; i ; i = TREE_CHAIN (i))
2006 tree i_name = TREE_PURPOSE (TREE_PURPOSE (i));
2010 for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
2011 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
2015 for (i = inputs; i ; i = TREE_CHAIN (i))
2017 tree i_name = TREE_PURPOSE (TREE_PURPOSE (i));
2021 for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
2022 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
2024 for (j = outputs; j ; j = TREE_CHAIN (j))
2025 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
2032 error ("duplicate asm operand name '%s'",
2033 TREE_STRING_POINTER (TREE_PURPOSE (TREE_PURPOSE (i))));
2037 /* A subroutine of expand_asm_operands. Resolve the names of the operands
2038 in *POUTPUTS and *PINPUTS to numbers, and replace the name expansions in
2039 STRING and in the constraints to those numbers. */
2042 resolve_asm_operand_names (tree string, tree outputs, tree inputs)
2048 /* Substitute [<name>] in input constraint strings. There should be no
2049 named operands in output constraints. */
2050 for (t = inputs; t ; t = TREE_CHAIN (t))
2052 const char *c = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
2053 if (strchr (c, '[') != NULL)
2055 p = buffer = xstrdup (c);
2056 while ((p = strchr (p, '[')) != NULL)
2057 p = resolve_operand_name_1 (p, outputs, inputs);
2058 TREE_VALUE (TREE_PURPOSE (t))
2059 = build_string (strlen (buffer), buffer);
2064 if (strchr (TREE_STRING_POINTER (string), '[') == NULL)
2067 /* Assume that we will not need extra space to perform the substitution.
2068 This because we get to remove '[' and ']', which means we cannot have
2069 a problem until we have more than 999 operands. */
2071 p = buffer = xstrdup (TREE_STRING_POINTER (string));
2072 while ((p = strchr (p, '%')) != NULL)
2076 else if (ISALPHA (p[1]) && p[2] == '[')
2084 p = resolve_operand_name_1 (p, outputs, inputs);
2087 string = build_string (strlen (buffer), buffer);
2093 /* A subroutine of resolve_operand_names. P points to the '[' for a
2094 potential named operand of the form [<name>]. In place, replace
2095 the name and brackets with a number. Return a pointer to the
2096 balance of the string after substitution. */
2099 resolve_operand_name_1 (p, outputs, inputs)
2101 tree outputs, inputs;
2108 /* Collect the operand name. */
2109 q = strchr (p, ']');
2112 error ("missing close brace for named operand");
2113 return strchr (p, '\0');
2117 /* Resolve the name to a number. */
2118 for (op = 0, t = outputs; t ; t = TREE_CHAIN (t), op++)
2120 tree name = TREE_PURPOSE (TREE_PURPOSE (t));
2123 const char *c = TREE_STRING_POINTER (name);
2124 if (strncmp (c, p + 1, len) == 0 && c[len] == '\0')
2128 for (t = inputs; t ; t = TREE_CHAIN (t), op++)
2130 tree name = TREE_PURPOSE (TREE_PURPOSE (t));
2133 const char *c = TREE_STRING_POINTER (name);
2134 if (strncmp (c, p + 1, len) == 0 && c[len] == '\0')
2140 error ("undefined named operand '%s'", p + 1);
2144 /* Replace the name with the number. Unfortunately, not all libraries
2145 get the return value of sprintf correct, so search for the end of the
2146 generated string by hand. */
2147 sprintf (p, "%d", op);
2148 p = strchr (p, '\0');
2150 /* Verify the no extra buffer space assumption. */
2154 /* Shift the rest of the buffer down to fill the gap. */
2155 memmove (p, q + 1, strlen (q + 1) + 1);
2160 /* Generate RTL to evaluate the expression EXP
2161 and remember it in case this is the VALUE in a ({... VALUE; }) constr.
2162 Provided just for backward-compatibility. expand_expr_stmt_value()
2163 should be used for new code. */
2166 expand_expr_stmt (exp)
2169 expand_expr_stmt_value (exp, -1, 1);
2172 /* Generate RTL to evaluate the expression EXP. WANT_VALUE tells
2173 whether to (1) save the value of the expression, (0) discard it or
2174 (-1) use expr_stmts_for_value to tell. The use of -1 is
2175 deprecated, and retained only for backward compatibility. */
2178 expand_expr_stmt_value (exp, want_value, maybe_last)
2180 int want_value, maybe_last;
2185 if (want_value == -1)
2186 want_value = expr_stmts_for_value != 0;
2188 /* If -Wextra, warn about statements with no side effects,
2189 except for an explicit cast to void (e.g. for assert()), and
2190 except for last statement in ({...}) where they may be useful. */
2192 && (expr_stmts_for_value == 0 || ! maybe_last)
2193 && exp != error_mark_node)
2195 if (! TREE_SIDE_EFFECTS (exp))
2197 if (warn_unused_value
2198 && !(TREE_CODE (exp) == CONVERT_EXPR
2199 && VOID_TYPE_P (TREE_TYPE (exp))))
2200 warning ("%Hstatement with no effect", &emit_locus);
2202 else if (warn_unused_value)
2203 warn_if_unused_value (exp);
2206 /* If EXP is of function type and we are expanding statements for
2207 value, convert it to pointer-to-function. */
2208 if (want_value && TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE)
2209 exp = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (exp)), exp);
2211 /* The call to `expand_expr' could cause last_expr_type and
2212 last_expr_value to get reset. Therefore, we set last_expr_value
2213 and last_expr_type *after* calling expand_expr. */
2214 value = expand_expr (exp, want_value ? NULL_RTX : const0_rtx,
2216 type = TREE_TYPE (exp);
2218 /* If all we do is reference a volatile value in memory,
2219 copy it to a register to be sure it is actually touched. */
2220 if (value && GET_CODE (value) == MEM && TREE_THIS_VOLATILE (exp))
2222 if (TYPE_MODE (type) == VOIDmode)
2224 else if (TYPE_MODE (type) != BLKmode)
2225 value = copy_to_reg (value);
2228 rtx lab = gen_label_rtx ();
2230 /* Compare the value with itself to reference it. */
2231 emit_cmp_and_jump_insns (value, value, EQ,
2232 expand_expr (TYPE_SIZE (type),
2233 NULL_RTX, VOIDmode, 0),
2239 /* If this expression is part of a ({...}) and is in memory, we may have
2240 to preserve temporaries. */
2241 preserve_temp_slots (value);
2243 /* Free any temporaries used to evaluate this expression. Any temporary
2244 used as a result of this expression will already have been preserved
2250 last_expr_value = value;
2251 last_expr_type = type;
2257 /* Warn if EXP contains any computations whose results are not used.
2258 Return 1 if a warning is printed; 0 otherwise. */
2261 warn_if_unused_value (exp)
2264 if (TREE_USED (exp))
2267 /* Don't warn about void constructs. This includes casting to void,
2268 void function calls, and statement expressions with a final cast
2270 if (VOID_TYPE_P (TREE_TYPE (exp)))
2273 switch (TREE_CODE (exp))
2275 case PREINCREMENT_EXPR:
2276 case POSTINCREMENT_EXPR:
2277 case PREDECREMENT_EXPR:
2278 case POSTDECREMENT_EXPR:
2283 case METHOD_CALL_EXPR:
2285 case TRY_CATCH_EXPR:
2286 case WITH_CLEANUP_EXPR:
2291 /* For a binding, warn if no side effect within it. */
2292 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2295 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2297 case TRUTH_ORIF_EXPR:
2298 case TRUTH_ANDIF_EXPR:
2299 /* In && or ||, warn if 2nd operand has no side effect. */
2300 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2303 if (TREE_NO_UNUSED_WARNING (exp))
2305 if (warn_if_unused_value (TREE_OPERAND (exp, 0)))
2307 /* Let people do `(foo (), 0)' without a warning. */
2308 if (TREE_CONSTANT (TREE_OPERAND (exp, 1)))
2310 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2314 case NON_LVALUE_EXPR:
2315 /* Don't warn about conversions not explicit in the user's program. */
2316 if (TREE_NO_UNUSED_WARNING (exp))
2318 /* Assignment to a cast usually results in a cast of a modify.
2319 Don't complain about that. There can be an arbitrary number of
2320 casts before the modify, so we must loop until we find the first
2321 non-cast expression and then test to see if that is a modify. */
2323 tree tem = TREE_OPERAND (exp, 0);
2325 while (TREE_CODE (tem) == CONVERT_EXPR || TREE_CODE (tem) == NOP_EXPR)
2326 tem = TREE_OPERAND (tem, 0);
2328 if (TREE_CODE (tem) == MODIFY_EXPR || TREE_CODE (tem) == INIT_EXPR
2329 || TREE_CODE (tem) == CALL_EXPR)
2335 /* Don't warn about automatic dereferencing of references, since
2336 the user cannot control it. */
2337 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (exp, 0))) == REFERENCE_TYPE)
2338 return warn_if_unused_value (TREE_OPERAND (exp, 0));
2342 /* Referencing a volatile value is a side effect, so don't warn. */
2344 || TREE_CODE_CLASS (TREE_CODE (exp)) == 'r')
2345 && TREE_THIS_VOLATILE (exp))
2348 /* If this is an expression which has no operands, there is no value
2349 to be unused. There are no such language-independent codes,
2350 but front ends may define such. */
2351 if (TREE_CODE_CLASS (TREE_CODE (exp)) == 'e'
2352 && TREE_CODE_LENGTH (TREE_CODE (exp)) == 0)
2356 /* If this is an expression with side effects, don't warn. */
2357 if (TREE_SIDE_EFFECTS (exp))
2360 warning ("%Hvalue computed is not used", &emit_locus);
2365 /* Clear out the memory of the last expression evaluated. */
2370 last_expr_type = NULL_TREE;
2371 last_expr_value = NULL_RTX;
2374 /* Begin a statement-expression, i.e., a series of statements which
2375 may return a value. Return the RTL_EXPR for this statement expr.
2376 The caller must save that value and pass it to
2377 expand_end_stmt_expr. If HAS_SCOPE is nonzero, temporaries created
2378 in the statement-expression are deallocated at the end of the
2382 expand_start_stmt_expr (has_scope)
2387 /* Make the RTL_EXPR node temporary, not momentary,
2388 so that rtl_expr_chain doesn't become garbage. */
2389 t = make_node (RTL_EXPR);
2390 do_pending_stack_adjust ();
2392 start_sequence_for_rtl_expr (t);
2396 expr_stmts_for_value++;
2400 /* Restore the previous state at the end of a statement that returns a value.
2401 Returns a tree node representing the statement's value and the
2402 insns to compute the value.
2404 The nodes of that expression have been freed by now, so we cannot use them.
2405 But we don't want to do that anyway; the expression has already been
2406 evaluated and now we just want to use the value. So generate a RTL_EXPR
2407 with the proper type and RTL value.
2409 If the last substatement was not an expression,
2410 return something with type `void'. */
2413 expand_end_stmt_expr (t)
2418 if (! last_expr_value || ! last_expr_type)
2420 last_expr_value = const0_rtx;
2421 last_expr_type = void_type_node;
2423 else if (GET_CODE (last_expr_value) != REG && ! CONSTANT_P (last_expr_value))
2424 /* Remove any possible QUEUED. */
2425 last_expr_value = protect_from_queue (last_expr_value, 0);
2429 TREE_TYPE (t) = last_expr_type;
2430 RTL_EXPR_RTL (t) = last_expr_value;
2431 RTL_EXPR_SEQUENCE (t) = get_insns ();
2433 rtl_expr_chain = tree_cons (NULL_TREE, t, rtl_expr_chain);
2437 /* Don't consider deleting this expr or containing exprs at tree level. */
2438 TREE_SIDE_EFFECTS (t) = 1;
2439 /* Propagate volatility of the actual RTL expr. */
2440 TREE_THIS_VOLATILE (t) = volatile_refs_p (last_expr_value);
2443 expr_stmts_for_value--;
2448 /* Generate RTL for the start of an if-then. COND is the expression
2449 whose truth should be tested.
2451 If EXITFLAG is nonzero, this conditional is visible to
2452 `exit_something'. */
2455 expand_start_cond (cond, exitflag)
2459 struct nesting *thiscond = ALLOC_NESTING ();
2461 /* Make an entry on cond_stack for the cond we are entering. */
2463 thiscond->desc = COND_NESTING;
2464 thiscond->next = cond_stack;
2465 thiscond->all = nesting_stack;
2466 thiscond->depth = ++nesting_depth;
2467 thiscond->data.cond.next_label = gen_label_rtx ();
2468 /* Before we encounter an `else', we don't need a separate exit label
2469 unless there are supposed to be exit statements
2470 to exit this conditional. */
2471 thiscond->exit_label = exitflag ? gen_label_rtx () : 0;
2472 thiscond->data.cond.endif_label = thiscond->exit_label;
2473 cond_stack = thiscond;
2474 nesting_stack = thiscond;
2476 do_jump (cond, thiscond->data.cond.next_label, NULL_RTX);
2479 /* Generate RTL between then-clause and the elseif-clause
2480 of an if-then-elseif-.... */
2483 expand_start_elseif (cond)
2486 if (cond_stack->data.cond.endif_label == 0)
2487 cond_stack->data.cond.endif_label = gen_label_rtx ();
2488 emit_jump (cond_stack->data.cond.endif_label);
2489 emit_label (cond_stack->data.cond.next_label);
2490 cond_stack->data.cond.next_label = gen_label_rtx ();
2491 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
2494 /* Generate RTL between the then-clause and the else-clause
2495 of an if-then-else. */
2498 expand_start_else ()
2500 if (cond_stack->data.cond.endif_label == 0)
2501 cond_stack->data.cond.endif_label = gen_label_rtx ();
2503 emit_jump (cond_stack->data.cond.endif_label);
2504 emit_label (cond_stack->data.cond.next_label);
2505 cond_stack->data.cond.next_label = 0; /* No more _else or _elseif calls. */
2508 /* After calling expand_start_else, turn this "else" into an "else if"
2509 by providing another condition. */
2512 expand_elseif (cond)
2515 cond_stack->data.cond.next_label = gen_label_rtx ();
2516 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
2519 /* Generate RTL for the end of an if-then.
2520 Pop the record for it off of cond_stack. */
2525 struct nesting *thiscond = cond_stack;
2527 do_pending_stack_adjust ();
2528 if (thiscond->data.cond.next_label)
2529 emit_label (thiscond->data.cond.next_label);
2530 if (thiscond->data.cond.endif_label)
2531 emit_label (thiscond->data.cond.endif_label);
2533 POPSTACK (cond_stack);
2537 /* Generate RTL for the start of a loop. EXIT_FLAG is nonzero if this
2538 loop should be exited by `exit_something'. This is a loop for which
2539 `expand_continue' will jump to the top of the loop.
2541 Make an entry on loop_stack to record the labels associated with
2545 expand_start_loop (exit_flag)
2548 struct nesting *thisloop = ALLOC_NESTING ();
2550 /* Make an entry on loop_stack for the loop we are entering. */
2552 thisloop->desc = LOOP_NESTING;
2553 thisloop->next = loop_stack;
2554 thisloop->all = nesting_stack;
2555 thisloop->depth = ++nesting_depth;
2556 thisloop->data.loop.start_label = gen_label_rtx ();
2557 thisloop->data.loop.end_label = gen_label_rtx ();
2558 thisloop->data.loop.continue_label = thisloop->data.loop.start_label;
2559 thisloop->exit_label = exit_flag ? thisloop->data.loop.end_label : 0;
2560 loop_stack = thisloop;
2561 nesting_stack = thisloop;
2563 do_pending_stack_adjust ();
2565 emit_note (NOTE_INSN_LOOP_BEG);
2566 emit_label (thisloop->data.loop.start_label);
2571 /* Like expand_start_loop but for a loop where the continuation point
2572 (for expand_continue_loop) will be specified explicitly. */
2575 expand_start_loop_continue_elsewhere (exit_flag)
2578 struct nesting *thisloop = expand_start_loop (exit_flag);
2579 loop_stack->data.loop.continue_label = gen_label_rtx ();
2583 /* Begin a null, aka do { } while (0) "loop". But since the contents
2584 of said loop can still contain a break, we must frob the loop nest. */
2587 expand_start_null_loop ()
2589 struct nesting *thisloop = ALLOC_NESTING ();
2591 /* Make an entry on loop_stack for the loop we are entering. */
2593 thisloop->desc = LOOP_NESTING;
2594 thisloop->next = loop_stack;
2595 thisloop->all = nesting_stack;
2596 thisloop->depth = ++nesting_depth;
2597 thisloop->data.loop.start_label = emit_note (NOTE_INSN_DELETED);
2598 thisloop->data.loop.end_label = gen_label_rtx ();
2599 thisloop->data.loop.continue_label = thisloop->data.loop.end_label;
2600 thisloop->exit_label = thisloop->data.loop.end_label;
2601 loop_stack = thisloop;
2602 nesting_stack = thisloop;
2607 /* Specify the continuation point for a loop started with
2608 expand_start_loop_continue_elsewhere.
2609 Use this at the point in the code to which a continue statement
2613 expand_loop_continue_here ()
2615 do_pending_stack_adjust ();
2616 emit_note (NOTE_INSN_LOOP_CONT);
2617 emit_label (loop_stack->data.loop.continue_label);
2620 /* Finish a loop. Generate a jump back to the top and the loop-exit label.
2621 Pop the block off of loop_stack. */
2626 rtx start_label = loop_stack->data.loop.start_label;
2628 int eh_regions, debug_blocks;
2631 /* Mark the continue-point at the top of the loop if none elsewhere. */
2632 if (start_label == loop_stack->data.loop.continue_label)
2633 emit_note_before (NOTE_INSN_LOOP_CONT, start_label);
2635 do_pending_stack_adjust ();
2637 /* If the loop starts with a loop exit, roll that to the end where
2638 it will optimize together with the jump back.
2640 If the loop presently looks like this (in pseudo-C):
2644 if (test) goto end_label;
2650 transform it to look like:
2657 if (test) goto end_label;
2661 We rely on the presence of NOTE_INSN_LOOP_END_TOP_COND to mark
2662 the end of the entry conditional. Without this, our lexical scan
2663 can't tell the difference between an entry conditional and a
2664 body conditional that exits the loop. Mistaking the two means
2665 that we can misplace the NOTE_INSN_LOOP_CONT note, which can
2666 screw up loop unrolling.
2668 Things will be oh so much better when loop optimization is done
2669 off of a proper control flow graph... */
2671 /* Scan insns from the top of the loop looking for the END_TOP_COND note. */
2674 eh_regions = debug_blocks = 0;
2675 for (etc_note = start_label; etc_note ; etc_note = NEXT_INSN (etc_note))
2676 if (GET_CODE (etc_note) == NOTE)
2678 if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_LOOP_END_TOP_COND)
2681 /* We must not walk into a nested loop. */
2682 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_LOOP_BEG)
2684 etc_note = NULL_RTX;
2688 /* At the same time, scan for EH region notes, as we don't want
2689 to scrog region nesting. This shouldn't happen, but... */
2690 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_EH_REGION_BEG)
2692 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_EH_REGION_END)
2694 if (--eh_regions < 0)
2695 /* We've come to the end of an EH region, but never saw the
2696 beginning of that region. That means that an EH region
2697 begins before the top of the loop, and ends in the middle
2698 of it. The existence of such a situation violates a basic
2699 assumption in this code, since that would imply that even
2700 when EH_REGIONS is zero, we might move code out of an
2701 exception region. */
2705 /* Likewise for debug scopes. In this case we'll either (1) move
2706 all of the notes if they are properly nested or (2) leave the
2707 notes alone and only rotate the loop at high optimization
2708 levels when we expect to scrog debug info. */
2709 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_BLOCK_BEG)
2711 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_BLOCK_END)
2714 else if (INSN_P (etc_note))
2721 && (debug_blocks == 0 || optimize >= 2)
2722 && NEXT_INSN (etc_note) != NULL_RTX
2723 && ! any_condjump_p (get_last_insn ()))
2725 /* We found one. Move everything from START to ETC to the end
2726 of the loop, and add a jump from the top of the loop. */
2727 rtx top_label = gen_label_rtx ();
2728 rtx start_move = start_label;
2730 /* If the start label is preceded by a NOTE_INSN_LOOP_CONT note,
2731 then we want to move this note also. */
2732 if (GET_CODE (PREV_INSN (start_move)) == NOTE
2733 && NOTE_LINE_NUMBER (PREV_INSN (start_move)) == NOTE_INSN_LOOP_CONT)
2734 start_move = PREV_INSN (start_move);
2736 emit_label_before (top_label, start_move);
2738 /* Actually move the insns. If the debug scopes are nested, we
2739 can move everything at once. Otherwise we have to move them
2740 one by one and squeeze out the block notes. */
2741 if (debug_blocks == 0)
2742 reorder_insns (start_move, etc_note, get_last_insn ());
2745 rtx insn, next_insn;
2746 for (insn = start_move; insn; insn = next_insn)
2748 /* Figure out which insn comes after this one. We have
2749 to do this before we move INSN. */
2750 next_insn = (insn == etc_note ? NULL : NEXT_INSN (insn));
2752 if (GET_CODE (insn) == NOTE
2753 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
2754 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
2757 reorder_insns (insn, insn, get_last_insn ());
2761 /* Add the jump from the top of the loop. */
2762 emit_jump_insn_before (gen_jump (start_label), top_label);
2763 emit_barrier_before (top_label);
2764 start_label = top_label;
2767 emit_jump (start_label);
2768 emit_note (NOTE_INSN_LOOP_END);
2769 emit_label (loop_stack->data.loop.end_label);
2771 POPSTACK (loop_stack);
2776 /* Finish a null loop, aka do { } while (0). */
2779 expand_end_null_loop ()
2781 do_pending_stack_adjust ();
2782 emit_label (loop_stack->data.loop.end_label);
2784 POPSTACK (loop_stack);
2789 /* Generate a jump to the current loop's continue-point.
2790 This is usually the top of the loop, but may be specified
2791 explicitly elsewhere. If not currently inside a loop,
2792 return 0 and do nothing; caller will print an error message. */
2795 expand_continue_loop (whichloop)
2796 struct nesting *whichloop;
2798 /* Emit information for branch prediction. */
2801 if (flag_guess_branch_prob)
2803 note = emit_note (NOTE_INSN_PREDICTION);
2804 NOTE_PREDICTION (note) = NOTE_PREDICT (PRED_CONTINUE, IS_TAKEN);
2808 whichloop = loop_stack;
2811 expand_goto_internal (NULL_TREE, whichloop->data.loop.continue_label,
2816 /* Generate a jump to exit the current loop. If not currently inside a loop,
2817 return 0 and do nothing; caller will print an error message. */
2820 expand_exit_loop (whichloop)
2821 struct nesting *whichloop;
2825 whichloop = loop_stack;
2828 expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label, NULL_RTX);
2832 /* Generate a conditional jump to exit the current loop if COND
2833 evaluates to zero. If not currently inside a loop,
2834 return 0 and do nothing; caller will print an error message. */
2837 expand_exit_loop_if_false (whichloop, cond)
2838 struct nesting *whichloop;
2845 whichloop = loop_stack;
2849 if (integer_nonzerop (cond))
2851 if (integer_zerop (cond))
2852 return expand_exit_loop (whichloop);
2854 /* Check if we definitely won't need a fixup. */
2855 if (whichloop == nesting_stack)
2857 jumpifnot (cond, whichloop->data.loop.end_label);
2861 /* In order to handle fixups, we actually create a conditional jump
2862 around an unconditional branch to exit the loop. If fixups are
2863 necessary, they go before the unconditional branch. */
2865 label = gen_label_rtx ();
2866 jumpif (cond, label);
2867 expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label,
2874 /* Like expand_exit_loop_if_false except also emit a note marking
2875 the end of the conditional. Should only be used immediately
2876 after expand_loop_start. */
2879 expand_exit_loop_top_cond (whichloop, cond)
2880 struct nesting *whichloop;
2883 if (! expand_exit_loop_if_false (whichloop, cond))
2886 emit_note (NOTE_INSN_LOOP_END_TOP_COND);
2890 /* Return nonzero if we should preserve sub-expressions as separate
2891 pseudos. We never do so if we aren't optimizing. We always do so
2892 if -fexpensive-optimizations.
2894 Otherwise, we only do so if we are in the "early" part of a loop. I.e.,
2895 the loop may still be a small one. */
2898 preserve_subexpressions_p ()
2902 if (flag_expensive_optimizations)
2905 if (optimize == 0 || cfun == 0 || cfun->stmt == 0 || loop_stack == 0)
2908 insn = get_last_insn_anywhere ();
2911 && (INSN_UID (insn) - INSN_UID (loop_stack->data.loop.start_label)
2912 < n_non_fixed_regs * 3));
2916 /* Generate a jump to exit the current loop, conditional, binding contour
2917 or case statement. Not all such constructs are visible to this function,
2918 only those started with EXIT_FLAG nonzero. Individual languages use
2919 the EXIT_FLAG parameter to control which kinds of constructs you can
2922 If not currently inside anything that can be exited,
2923 return 0 and do nothing; caller will print an error message. */
2926 expand_exit_something ()
2930 for (n = nesting_stack; n; n = n->all)
2931 if (n->exit_label != 0)
2933 expand_goto_internal (NULL_TREE, n->exit_label, NULL_RTX);
2940 /* Generate RTL to return from the current function, with no value.
2941 (That is, we do not do anything about returning any value.) */
2944 expand_null_return ()
2948 last_insn = get_last_insn ();
2950 /* If this function was declared to return a value, but we
2951 didn't, clobber the return registers so that they are not
2952 propagated live to the rest of the function. */
2953 clobber_return_register ();
2955 expand_null_return_1 (last_insn);
2958 /* Try to guess whether the value of return means error code. */
2959 static enum br_predictor
2960 return_prediction (val)
2963 /* Different heuristics for pointers and scalars. */
2964 if (POINTER_TYPE_P (TREE_TYPE (DECL_RESULT (current_function_decl))))
2966 /* NULL is usually not returned. */
2967 if (val == const0_rtx)
2968 return PRED_NULL_RETURN;
2972 /* Negative return values are often used to indicate
2974 if (GET_CODE (val) == CONST_INT
2975 && INTVAL (val) < 0)
2976 return PRED_NEGATIVE_RETURN;
2977 /* Constant return values are also usually erors,
2978 zero/one often mean booleans so exclude them from the
2980 if (CONSTANT_P (val)
2981 && (val != const0_rtx && val != const1_rtx))
2982 return PRED_CONST_RETURN;
2984 return PRED_NO_PREDICTION;
2987 /* Generate RTL to return from the current function, with value VAL. */
2990 expand_value_return (val)
2995 enum br_predictor pred;
2997 if (flag_guess_branch_prob
2998 && (pred = return_prediction (val)) != PRED_NO_PREDICTION)
3000 /* Emit information for branch prediction. */
3003 note = emit_note (NOTE_INSN_PREDICTION);
3005 NOTE_PREDICTION (note) = NOTE_PREDICT (pred, NOT_TAKEN);
3009 last_insn = get_last_insn ();
3010 return_reg = DECL_RTL (DECL_RESULT (current_function_decl));
3012 /* Copy the value to the return location
3013 unless it's already there. */
3015 if (return_reg != val)
3017 tree type = TREE_TYPE (DECL_RESULT (current_function_decl));
3018 #ifdef PROMOTE_FUNCTION_RETURN
3019 int unsignedp = TREE_UNSIGNED (type);
3020 enum machine_mode old_mode
3021 = DECL_MODE (DECL_RESULT (current_function_decl));
3022 enum machine_mode mode
3023 = promote_mode (type, old_mode, &unsignedp, 1);
3025 if (mode != old_mode)
3026 val = convert_modes (mode, old_mode, val, unsignedp);
3028 if (GET_CODE (return_reg) == PARALLEL)
3029 emit_group_load (return_reg, val, int_size_in_bytes (type));
3031 emit_move_insn (return_reg, val);
3034 expand_null_return_1 (last_insn);
3037 /* Output a return with no value. If LAST_INSN is nonzero,
3038 pretend that the return takes place after LAST_INSN. */
3041 expand_null_return_1 (last_insn)
3044 rtx end_label = cleanup_label ? cleanup_label : return_label;
3046 clear_pending_stack_adjust ();
3047 do_pending_stack_adjust ();
3051 end_label = return_label = gen_label_rtx ();
3052 expand_goto_internal (NULL_TREE, end_label, last_insn);
3055 /* Generate RTL to evaluate the expression RETVAL and return it
3056 from the current function. */
3059 expand_return (retval)
3062 /* If there are any cleanups to be performed, then they will
3063 be inserted following LAST_INSN. It is desirable
3064 that the last_insn, for such purposes, should be the
3065 last insn before computing the return value. Otherwise, cleanups
3066 which call functions can clobber the return value. */
3067 /* ??? rms: I think that is erroneous, because in C++ it would
3068 run destructors on variables that might be used in the subsequent
3069 computation of the return value. */
3075 /* If function wants no value, give it none. */
3076 if (TREE_CODE (TREE_TYPE (TREE_TYPE (current_function_decl))) == VOID_TYPE)
3078 expand_expr (retval, NULL_RTX, VOIDmode, 0);
3080 expand_null_return ();
3084 if (retval == error_mark_node)
3086 /* Treat this like a return of no value from a function that
3088 expand_null_return ();
3091 else if (TREE_CODE (retval) == RESULT_DECL)
3092 retval_rhs = retval;
3093 else if ((TREE_CODE (retval) == MODIFY_EXPR || TREE_CODE (retval) == INIT_EXPR)
3094 && TREE_CODE (TREE_OPERAND (retval, 0)) == RESULT_DECL)
3095 retval_rhs = TREE_OPERAND (retval, 1);
3096 else if (VOID_TYPE_P (TREE_TYPE (retval)))
3097 /* Recognize tail-recursive call to void function. */
3098 retval_rhs = retval;
3100 retval_rhs = NULL_TREE;
3102 last_insn = get_last_insn ();
3104 /* Distribute return down conditional expr if either of the sides
3105 may involve tail recursion (see test below). This enhances the number
3106 of tail recursions we see. Don't do this always since it can produce
3107 sub-optimal code in some cases and we distribute assignments into
3108 conditional expressions when it would help. */
3110 if (optimize && retval_rhs != 0
3111 && frame_offset == 0
3112 && TREE_CODE (retval_rhs) == COND_EXPR
3113 && (TREE_CODE (TREE_OPERAND (retval_rhs, 1)) == CALL_EXPR
3114 || TREE_CODE (TREE_OPERAND (retval_rhs, 2)) == CALL_EXPR))
3116 rtx label = gen_label_rtx ();
3119 do_jump (TREE_OPERAND (retval_rhs, 0), label, NULL_RTX);
3120 start_cleanup_deferral ();
3121 expr = build (MODIFY_EXPR, TREE_TYPE (TREE_TYPE (current_function_decl)),
3122 DECL_RESULT (current_function_decl),
3123 TREE_OPERAND (retval_rhs, 1));
3124 TREE_SIDE_EFFECTS (expr) = 1;
3125 expand_return (expr);
3128 expr = build (MODIFY_EXPR, TREE_TYPE (TREE_TYPE (current_function_decl)),
3129 DECL_RESULT (current_function_decl),
3130 TREE_OPERAND (retval_rhs, 2));
3131 TREE_SIDE_EFFECTS (expr) = 1;
3132 expand_return (expr);
3133 end_cleanup_deferral ();
3137 result_rtl = DECL_RTL (DECL_RESULT (current_function_decl));
3139 /* If the result is an aggregate that is being returned in one (or more)
3140 registers, load the registers here. The compiler currently can't handle
3141 copying a BLKmode value into registers. We could put this code in a
3142 more general area (for use by everyone instead of just function
3143 call/return), but until this feature is generally usable it is kept here
3144 (and in expand_call). The value must go into a pseudo in case there
3145 are cleanups that will clobber the real return register. */
3148 && TYPE_MODE (TREE_TYPE (retval_rhs)) == BLKmode
3149 && GET_CODE (result_rtl) == REG)
3152 unsigned HOST_WIDE_INT bitpos, xbitpos;
3153 unsigned HOST_WIDE_INT big_endian_correction = 0;
3154 unsigned HOST_WIDE_INT bytes
3155 = int_size_in_bytes (TREE_TYPE (retval_rhs));
3156 int n_regs = (bytes + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
3157 unsigned int bitsize
3158 = MIN (TYPE_ALIGN (TREE_TYPE (retval_rhs)), BITS_PER_WORD);
3159 rtx *result_pseudos = (rtx *) alloca (sizeof (rtx) * n_regs);
3160 rtx result_reg, src = NULL_RTX, dst = NULL_RTX;
3161 rtx result_val = expand_expr (retval_rhs, NULL_RTX, VOIDmode, 0);
3162 enum machine_mode tmpmode, result_reg_mode;
3166 expand_null_return ();
3170 /* Structures whose size is not a multiple of a word are aligned
3171 to the least significant byte (to the right). On a BYTES_BIG_ENDIAN
3172 machine, this means we must skip the empty high order bytes when
3173 calculating the bit offset. */
3174 if (BYTES_BIG_ENDIAN
3175 && bytes % UNITS_PER_WORD)
3176 big_endian_correction = (BITS_PER_WORD - ((bytes % UNITS_PER_WORD)
3179 /* Copy the structure BITSIZE bits at a time. */
3180 for (bitpos = 0, xbitpos = big_endian_correction;
3181 bitpos < bytes * BITS_PER_UNIT;
3182 bitpos += bitsize, xbitpos += bitsize)
3184 /* We need a new destination pseudo each time xbitpos is
3185 on a word boundary and when xbitpos == big_endian_correction
3186 (the first time through). */
3187 if (xbitpos % BITS_PER_WORD == 0
3188 || xbitpos == big_endian_correction)
3190 /* Generate an appropriate register. */
3191 dst = gen_reg_rtx (word_mode);
3192 result_pseudos[xbitpos / BITS_PER_WORD] = dst;
3194 /* Clear the destination before we move anything into it. */
3195 emit_move_insn (dst, CONST0_RTX (GET_MODE (dst)));
3198 /* We need a new source operand each time bitpos is on a word
3200 if (bitpos % BITS_PER_WORD == 0)
3201 src = operand_subword_force (result_val,
3202 bitpos / BITS_PER_WORD,
3205 /* Use bitpos for the source extraction (left justified) and
3206 xbitpos for the destination store (right justified). */
3207 store_bit_field (dst, bitsize, xbitpos % BITS_PER_WORD, word_mode,
3208 extract_bit_field (src, bitsize,
3209 bitpos % BITS_PER_WORD, 1,
3210 NULL_RTX, word_mode, word_mode,
3215 /* Find the smallest integer mode large enough to hold the
3216 entire structure and use that mode instead of BLKmode
3217 on the USE insn for the return register. */
3218 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
3219 tmpmode != VOIDmode;
3220 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
3221 /* Have we found a large enough mode? */
3222 if (GET_MODE_SIZE (tmpmode) >= bytes)
3225 /* No suitable mode found. */
3226 if (tmpmode == VOIDmode)
3229 PUT_MODE (result_rtl, tmpmode);
3231 if (GET_MODE_SIZE (tmpmode) < GET_MODE_SIZE (word_mode))
3232 result_reg_mode = word_mode;
3234 result_reg_mode = tmpmode;
3235 result_reg = gen_reg_rtx (result_reg_mode);
3238 for (i = 0; i < n_regs; i++)
3239 emit_move_insn (operand_subword (result_reg, i, 0, result_reg_mode),
3242 if (tmpmode != result_reg_mode)
3243 result_reg = gen_lowpart (tmpmode, result_reg);
3245 expand_value_return (result_reg);
3247 else if (retval_rhs != 0
3248 && !VOID_TYPE_P (TREE_TYPE (retval_rhs))
3249 && (GET_CODE (result_rtl) == REG
3250 || (GET_CODE (result_rtl) == PARALLEL)))
3252 /* Calculate the return value into a temporary (usually a pseudo
3254 tree ot = TREE_TYPE (DECL_RESULT (current_function_decl));
3255 tree nt = build_qualified_type (ot, TYPE_QUALS (ot) | TYPE_QUAL_CONST);
3257 val = assign_temp (nt, 0, 0, 1);
3258 val = expand_expr (retval_rhs, val, GET_MODE (val), 0);
3259 val = force_not_mem (val);
3261 /* Return the calculated value, doing cleanups first. */
3262 expand_value_return (val);
3266 /* No cleanups or no hard reg used;
3267 calculate value into hard return reg. */
3268 expand_expr (retval, const0_rtx, VOIDmode, 0);
3270 expand_value_return (result_rtl);
3274 /* Attempt to optimize a potential tail recursion call into a goto.
3275 ARGUMENTS are the arguments to a CALL_EXPR; LAST_INSN indicates
3276 where to place the jump to the tail recursion label.
3278 Return TRUE if the call was optimized into a goto. */
3281 optimize_tail_recursion (arguments, last_insn)
3285 /* Finish checking validity, and if valid emit code to set the
3286 argument variables for the new call. */
3287 if (tail_recursion_args (arguments, DECL_ARGUMENTS (current_function_decl)))
3289 if (tail_recursion_label == 0)
3291 tail_recursion_label = gen_label_rtx ();
3292 emit_label_after (tail_recursion_label,
3293 tail_recursion_reentry);
3296 expand_goto_internal (NULL_TREE, tail_recursion_label, last_insn);
3303 /* Emit code to alter this function's formal parms for a tail-recursive call.
3304 ACTUALS is a list of actual parameter expressions (chain of TREE_LISTs).
3305 FORMALS is the chain of decls of formals.
3306 Return 1 if this can be done;
3307 otherwise return 0 and do not emit any code. */
3310 tail_recursion_args (actuals, formals)
3311 tree actuals, formals;
3313 tree a = actuals, f = formals;
3317 /* Check that number and types of actuals are compatible
3318 with the formals. This is not always true in valid C code.
3319 Also check that no formal needs to be addressable
3320 and that all formals are scalars. */
3322 /* Also count the args. */
3324 for (a = actuals, f = formals, i = 0; a && f; a = TREE_CHAIN (a), f = TREE_CHAIN (f), i++)
3326 if (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_VALUE (a)))
3327 != TYPE_MAIN_VARIANT (TREE_TYPE (f)))
3329 if (GET_CODE (DECL_RTL (f)) != REG || DECL_MODE (f) == BLKmode)
3332 if (a != 0 || f != 0)
3335 /* Compute all the actuals. */
3337 argvec = (rtx *) alloca (i * sizeof (rtx));
3339 for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
3340 argvec[i] = expand_expr (TREE_VALUE (a), NULL_RTX, VOIDmode, 0);
3342 /* Find which actual values refer to current values of previous formals.
3343 Copy each of them now, before any formal is changed. */
3345 for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
3349 for (f = formals, j = 0; j < i; f = TREE_CHAIN (f), j++)
3350 if (reg_mentioned_p (DECL_RTL (f), argvec[i]))
3356 argvec[i] = copy_to_reg (argvec[i]);
3359 /* Store the values of the actuals into the formals. */
3361 for (f = formals, a = actuals, i = 0; f;
3362 f = TREE_CHAIN (f), a = TREE_CHAIN (a), i++)
3364 if (GET_MODE (DECL_RTL (f)) == GET_MODE (argvec[i]))
3365 emit_move_insn (DECL_RTL (f), argvec[i]);
3368 rtx tmp = argvec[i];
3369 int unsignedp = TREE_UNSIGNED (TREE_TYPE (TREE_VALUE (a)));
3370 promote_mode(TREE_TYPE (TREE_VALUE (a)), GET_MODE (tmp),
3372 if (DECL_MODE (f) != GET_MODE (DECL_RTL (f)))
3374 tmp = gen_reg_rtx (DECL_MODE (f));
3375 convert_move (tmp, argvec[i], unsignedp);
3377 convert_move (DECL_RTL (f), tmp, unsignedp);
3385 /* Generate the RTL code for entering a binding contour.
3386 The variables are declared one by one, by calls to `expand_decl'.
3388 FLAGS is a bitwise or of the following flags:
3390 1 - Nonzero if this construct should be visible to
3393 2 - Nonzero if this contour does not require a
3394 NOTE_INSN_BLOCK_BEG note. Virtually all calls from
3395 language-independent code should set this flag because they
3396 will not create corresponding BLOCK nodes. (There should be
3397 a one-to-one correspondence between NOTE_INSN_BLOCK_BEG notes
3398 and BLOCKs.) If this flag is set, MARK_ENDS should be zero
3399 when expand_end_bindings is called.
3401 If we are creating a NOTE_INSN_BLOCK_BEG note, a BLOCK may
3402 optionally be supplied. If so, it becomes the NOTE_BLOCK for the
3406 expand_start_bindings_and_block (flags, block)
3410 struct nesting *thisblock = ALLOC_NESTING ();
3412 int exit_flag = ((flags & 1) != 0);
3413 int block_flag = ((flags & 2) == 0);
3415 /* If a BLOCK is supplied, then the caller should be requesting a
3416 NOTE_INSN_BLOCK_BEG note. */
3417 if (!block_flag && block)
3420 /* Create a note to mark the beginning of the block. */
3423 note = emit_note (NOTE_INSN_BLOCK_BEG);
3424 NOTE_BLOCK (note) = block;
3427 note = emit_note (NOTE_INSN_DELETED);
3429 /* Make an entry on block_stack for the block we are entering. */
3431 thisblock->desc = BLOCK_NESTING;
3432 thisblock->next = block_stack;
3433 thisblock->all = nesting_stack;
3434 thisblock->depth = ++nesting_depth;
3435 thisblock->data.block.stack_level = 0;
3436 thisblock->data.block.cleanups = 0;
3437 thisblock->data.block.exception_region = 0;
3438 thisblock->data.block.block_target_temp_slot_level = target_temp_slot_level;
3440 thisblock->data.block.conditional_code = 0;
3441 thisblock->data.block.last_unconditional_cleanup = note;
3442 /* When we insert instructions after the last unconditional cleanup,
3443 we don't adjust last_insn. That means that a later add_insn will
3444 clobber the instructions we've just added. The easiest way to
3445 fix this is to just insert another instruction here, so that the
3446 instructions inserted after the last unconditional cleanup are
3447 never the last instruction. */
3448 emit_note (NOTE_INSN_DELETED);
3451 && !(block_stack->data.block.cleanups == NULL_TREE
3452 && block_stack->data.block.outer_cleanups == NULL_TREE))
3453 thisblock->data.block.outer_cleanups
3454 = tree_cons (NULL_TREE, block_stack->data.block.cleanups,
3455 block_stack->data.block.outer_cleanups);
3457 thisblock->data.block.outer_cleanups = 0;
3458 thisblock->data.block.label_chain = 0;
3459 thisblock->data.block.innermost_stack_block = stack_block_stack;
3460 thisblock->data.block.first_insn = note;
3461 thisblock->data.block.block_start_count = ++current_block_start_count;
3462 thisblock->exit_label = exit_flag ? gen_label_rtx () : 0;
3463 block_stack = thisblock;
3464 nesting_stack = thisblock;
3466 /* Make a new level for allocating stack slots. */
3470 /* Specify the scope of temporaries created by TARGET_EXPRs. Similar
3471 to CLEANUP_POINT_EXPR, but handles cases when a series of calls to
3472 expand_expr are made. After we end the region, we know that all
3473 space for all temporaries that were created by TARGET_EXPRs will be
3474 destroyed and their space freed for reuse. */
3477 expand_start_target_temps ()
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. */
3483 /* Start a new binding layer that will keep track of all cleanup
3484 actions to be performed. */
3485 expand_start_bindings (2);
3487 target_temp_slot_level = temp_slot_level;
3491 expand_end_target_temps ()
3493 expand_end_bindings (NULL_TREE, 0, 0);
3495 /* This is so that even if the result is preserved, the space
3496 allocated will be freed, as we know that it is no longer in use. */
3500 /* Given a pointer to a BLOCK node return nonzero if (and only if) the node
3501 in question represents the outermost pair of curly braces (i.e. the "body
3502 block") of a function or method.
3504 For any BLOCK node representing a "body block" of a function or method, the
3505 BLOCK_SUPERCONTEXT of the node will point to another BLOCK node which
3506 represents the outermost (function) scope for the function or method (i.e.
3507 the one which includes the formal parameters). The BLOCK_SUPERCONTEXT of
3508 *that* node in turn will point to the relevant FUNCTION_DECL node. */
3511 is_body_block (stmt)
3514 if (lang_hooks.no_body_blocks)
3517 if (TREE_CODE (stmt) == BLOCK)
3519 tree parent = BLOCK_SUPERCONTEXT (stmt);
3521 if (parent && TREE_CODE (parent) == BLOCK)
3523 tree grandparent = BLOCK_SUPERCONTEXT (parent);
3525 if (grandparent && TREE_CODE (grandparent) == FUNCTION_DECL)
3533 /* True if we are currently emitting insns in an area of output code
3534 that is controlled by a conditional expression. This is used by
3535 the cleanup handling code to generate conditional cleanup actions. */
3538 conditional_context ()
3540 return block_stack && block_stack->data.block.conditional_code;
3543 /* Return an opaque pointer to the current nesting level, so frontend code
3544 can check its own sanity. */
3547 current_nesting_level ()
3549 return cfun ? block_stack : 0;
3552 /* Emit a handler label for a nonlocal goto handler.
3553 Also emit code to store the handler label in SLOT before BEFORE_INSN. */
3556 expand_nl_handler_label (slot, before_insn)
3557 rtx slot, before_insn;
3560 rtx handler_label = gen_label_rtx ();
3562 /* Don't let cleanup_cfg delete the handler. */
3563 LABEL_PRESERVE_P (handler_label) = 1;
3566 emit_move_insn (slot, gen_rtx_LABEL_REF (Pmode, handler_label));
3567 insns = get_insns ();
3569 emit_insn_before (insns, before_insn);
3571 emit_label (handler_label);
3573 return handler_label;
3576 /* Emit code to restore vital registers at the beginning of a nonlocal goto
3579 expand_nl_goto_receiver ()
3581 #ifdef HAVE_nonlocal_goto
3582 if (! HAVE_nonlocal_goto)
3584 /* First adjust our frame pointer to its actual value. It was
3585 previously set to the start of the virtual area corresponding to
3586 the stacked variables when we branched here and now needs to be
3587 adjusted to the actual hardware fp value.
3589 Assignments are to virtual registers are converted by
3590 instantiate_virtual_regs into the corresponding assignment
3591 to the underlying register (fp in this case) that makes
3592 the original assignment true.
3593 So the following insn will actually be
3594 decrementing fp by STARTING_FRAME_OFFSET. */
3595 emit_move_insn (virtual_stack_vars_rtx, hard_frame_pointer_rtx);
3597 #if ARG_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3598 if (fixed_regs[ARG_POINTER_REGNUM])
3600 #ifdef ELIMINABLE_REGS
3601 /* If the argument pointer can be eliminated in favor of the
3602 frame pointer, we don't need to restore it. We assume here
3603 that if such an elimination is present, it can always be used.
3604 This is the case on all known machines; if we don't make this
3605 assumption, we do unnecessary saving on many machines. */
3606 static const struct elims {const int from, to;} elim_regs[] = ELIMINABLE_REGS;
3609 for (i = 0; i < ARRAY_SIZE (elim_regs); i++)
3610 if (elim_regs[i].from == ARG_POINTER_REGNUM
3611 && elim_regs[i].to == HARD_FRAME_POINTER_REGNUM)
3614 if (i == ARRAY_SIZE (elim_regs))
3617 /* Now restore our arg pointer from the address at which it
3618 was saved in our stack frame. */
3619 emit_move_insn (virtual_incoming_args_rtx,
3620 copy_to_reg (get_arg_pointer_save_area (cfun)));
3625 #ifdef HAVE_nonlocal_goto_receiver
3626 if (HAVE_nonlocal_goto_receiver)
3627 emit_insn (gen_nonlocal_goto_receiver ());
3631 /* Make handlers for nonlocal gotos taking place in the function calls in
3635 expand_nl_goto_receivers (thisblock)
3636 struct nesting *thisblock;
3639 rtx afterward = gen_label_rtx ();
3644 /* Record the handler address in the stack slot for that purpose,
3645 during this block, saving and restoring the outer value. */
3646 if (thisblock->next != 0)
3647 for (slot = nonlocal_goto_handler_slots; slot; slot = XEXP (slot, 1))
3649 rtx save_receiver = gen_reg_rtx (Pmode);
3650 emit_move_insn (XEXP (slot, 0), save_receiver);
3653 emit_move_insn (save_receiver, XEXP (slot, 0));
3654 insns = get_insns ();
3656 emit_insn_before (insns, thisblock->data.block.first_insn);
3659 /* Jump around the handlers; they run only when specially invoked. */
3660 emit_jump (afterward);
3662 /* Make a separate handler for each label. */
3663 link = nonlocal_labels;
3664 slot = nonlocal_goto_handler_slots;
3665 label_list = NULL_RTX;
3666 for (; link; link = TREE_CHAIN (link), slot = XEXP (slot, 1))
3667 /* Skip any labels we shouldn't be able to jump to from here,
3668 we generate one special handler for all of them below which just calls
3670 if (! DECL_TOO_LATE (TREE_VALUE (link)))
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);
3677 expand_nl_goto_receiver ();
3679 /* Jump to the "real" nonlocal label. */
3680 expand_goto (TREE_VALUE (link));
3683 /* A second pass over all nonlocal labels; this time we handle those
3684 we should not be able to jump to at this point. */
3685 link = nonlocal_labels;
3686 slot = nonlocal_goto_handler_slots;
3688 for (; link; link = TREE_CHAIN (link), slot = XEXP (slot, 1))
3689 if (DECL_TOO_LATE (TREE_VALUE (link)))
3692 lab = expand_nl_handler_label (XEXP (slot, 0),
3693 thisblock->data.block.first_insn);
3694 label_list = gen_rtx_EXPR_LIST (VOIDmode, lab, label_list);
3700 expand_nl_goto_receiver ();
3701 expand_builtin_trap ();
3704 nonlocal_goto_handler_labels = label_list;
3705 emit_label (afterward);
3708 /* Warn about any unused VARS (which may contain nodes other than
3709 VAR_DECLs, but such nodes are ignored). The nodes are connected
3710 via the TREE_CHAIN field. */
3713 warn_about_unused_variables (vars)
3718 if (warn_unused_variable)
3719 for (decl = vars; decl; decl = TREE_CHAIN (decl))
3720 if (TREE_CODE (decl) == VAR_DECL
3721 && ! TREE_USED (decl)
3722 && ! DECL_IN_SYSTEM_HEADER (decl)
3723 && DECL_NAME (decl) && ! DECL_ARTIFICIAL (decl))
3724 warning_with_decl (decl, "unused variable `%s'");
3727 /* Generate RTL code to terminate a binding contour.
3729 VARS is the chain of VAR_DECL nodes for the variables bound in this
3730 contour. There may actually be other nodes in this chain, but any
3731 nodes other than VAR_DECLS are ignored.
3733 MARK_ENDS is nonzero if we should put a note at the beginning
3734 and end of this binding contour.
3736 DONT_JUMP_IN is positive if it is not valid to jump into this contour,
3737 zero if we can jump into this contour only if it does not have a saved
3738 stack level, and negative if we are not to check for invalid use of
3739 labels (because the front end does that). */
3742 expand_end_bindings (vars, mark_ends, dont_jump_in)
3747 struct nesting *thisblock = block_stack;
3749 /* If any of the variables in this scope were not used, warn the
3751 warn_about_unused_variables (vars);
3753 if (thisblock->exit_label)
3755 do_pending_stack_adjust ();
3756 emit_label (thisblock->exit_label);
3759 /* If necessary, make handlers for nonlocal gotos taking
3760 place in the function calls in this block. */
3761 if (function_call_count != 0 && nonlocal_labels
3762 /* Make handler for outermost block
3763 if there were any nonlocal gotos to this function. */
3764 && (thisblock->next == 0 ? current_function_has_nonlocal_label
3765 /* Make handler for inner block if it has something
3766 special to do when you jump out of it. */
3767 : (thisblock->data.block.cleanups != 0
3768 || thisblock->data.block.stack_level != 0)))
3769 expand_nl_goto_receivers (thisblock);
3771 /* Don't allow jumping into a block that has a stack level.
3772 Cleanups are allowed, though. */
3773 if (dont_jump_in > 0
3774 || (dont_jump_in == 0 && thisblock->data.block.stack_level != 0))
3776 struct label_chain *chain;
3778 /* Any labels in this block are no longer valid to go to.
3779 Mark them to cause an error message. */
3780 for (chain = thisblock->data.block.label_chain; chain; chain = chain->next)
3782 DECL_TOO_LATE (chain->label) = 1;
3783 /* If any goto without a fixup came to this label,
3784 that must be an error, because gotos without fixups
3785 come from outside all saved stack-levels. */
3786 if (TREE_ADDRESSABLE (chain->label))
3787 error_with_decl (chain->label,
3788 "label `%s' used before containing binding contour");
3792 /* Restore stack level in effect before the block
3793 (only if variable-size objects allocated). */
3794 /* Perform any cleanups associated with the block. */
3796 if (thisblock->data.block.stack_level != 0
3797 || thisblock->data.block.cleanups != 0)
3802 /* Don't let cleanups affect ({...}) constructs. */
3803 int old_expr_stmts_for_value = expr_stmts_for_value;
3804 rtx old_last_expr_value = last_expr_value;
3805 tree old_last_expr_type = last_expr_type;
3806 expr_stmts_for_value = 0;
3808 /* Only clean up here if this point can actually be reached. */
3809 insn = get_last_insn ();
3810 if (GET_CODE (insn) == NOTE)
3811 insn = prev_nonnote_insn (insn);
3812 reachable = (! insn || GET_CODE (insn) != BARRIER);
3814 /* Do the cleanups. */
3815 expand_cleanups (thisblock->data.block.cleanups, 0, reachable);
3817 do_pending_stack_adjust ();
3819 expr_stmts_for_value = old_expr_stmts_for_value;
3820 last_expr_value = old_last_expr_value;
3821 last_expr_type = old_last_expr_type;
3823 /* Restore the stack level. */
3825 if (reachable && thisblock->data.block.stack_level != 0)
3827 emit_stack_restore (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3828 thisblock->data.block.stack_level, NULL_RTX);
3829 if (nonlocal_goto_handler_slots != 0)
3830 emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level,
3834 /* Any gotos out of this block must also do these things.
3835 Also report any gotos with fixups that came to labels in this
3837 fixup_gotos (thisblock,
3838 thisblock->data.block.stack_level,
3839 thisblock->data.block.cleanups,
3840 thisblock->data.block.first_insn,
3844 /* Mark the beginning and end of the scope if requested.
3845 We do this now, after running cleanups on the variables
3846 just going out of scope, so they are in scope for their cleanups. */
3850 rtx note = emit_note (NOTE_INSN_BLOCK_END);
3851 NOTE_BLOCK (note) = NOTE_BLOCK (thisblock->data.block.first_insn);
3854 /* Get rid of the beginning-mark if we don't make an end-mark. */
3855 NOTE_LINE_NUMBER (thisblock->data.block.first_insn) = NOTE_INSN_DELETED;
3857 /* Restore the temporary level of TARGET_EXPRs. */
3858 target_temp_slot_level = thisblock->data.block.block_target_temp_slot_level;
3860 /* Restore block_stack level for containing block. */
3862 stack_block_stack = thisblock->data.block.innermost_stack_block;
3863 POPSTACK (block_stack);
3865 /* Pop the stack slot nesting and free any slots at this level. */
3869 /* Generate code to save the stack pointer at the start of the current block
3870 and set up to restore it on exit. */
3873 save_stack_pointer ()
3875 struct nesting *thisblock = block_stack;
3877 if (thisblock->data.block.stack_level == 0)
3879 emit_stack_save (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3880 &thisblock->data.block.stack_level,
3881 thisblock->data.block.first_insn);
3882 stack_block_stack = thisblock;
3886 /* Generate RTL for the automatic variable declaration DECL.
3887 (Other kinds of declarations are simply ignored if seen here.) */
3895 type = TREE_TYPE (decl);
3897 /* For a CONST_DECL, set mode, alignment, and sizes from those of the
3898 type in case this node is used in a reference. */
3899 if (TREE_CODE (decl) == CONST_DECL)
3901 DECL_MODE (decl) = TYPE_MODE (type);
3902 DECL_ALIGN (decl) = TYPE_ALIGN (type);
3903 DECL_SIZE (decl) = TYPE_SIZE (type);
3904 DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (type);
3908 /* Otherwise, only automatic variables need any expansion done. Static and
3909 external variables, and external functions, will be handled by
3910 `assemble_variable' (called from finish_decl). TYPE_DECL requires
3911 nothing. PARM_DECLs are handled in `assign_parms'. */
3912 if (TREE_CODE (decl) != VAR_DECL)
3915 if (TREE_STATIC (decl) || DECL_EXTERNAL (decl))
3918 /* Create the RTL representation for the variable. */
3920 if (type == error_mark_node)
3921 SET_DECL_RTL (decl, gen_rtx_MEM (BLKmode, const0_rtx));
3923 else if (DECL_SIZE (decl) == 0)
3924 /* Variable with incomplete type. */
3927 if (DECL_INITIAL (decl) == 0)
3928 /* Error message was already done; now avoid a crash. */
3929 x = gen_rtx_MEM (BLKmode, const0_rtx);
3931 /* An initializer is going to decide the size of this array.
3932 Until we know the size, represent its address with a reg. */
3933 x = gen_rtx_MEM (BLKmode, gen_reg_rtx (Pmode));
3935 set_mem_attributes (x, decl, 1);
3936 SET_DECL_RTL (decl, x);
3938 else if (DECL_MODE (decl) != BLKmode
3939 /* If -ffloat-store, don't put explicit float vars
3941 && !(flag_float_store
3942 && TREE_CODE (type) == REAL_TYPE)
3943 && ! TREE_THIS_VOLATILE (decl)
3944 && ! DECL_NONLOCAL (decl)
3945 && (DECL_REGISTER (decl) || DECL_ARTIFICIAL (decl) || optimize))
3947 /* Automatic variable that can go in a register. */
3948 int unsignedp = TREE_UNSIGNED (type);
3949 enum machine_mode reg_mode
3950 = promote_mode (type, DECL_MODE (decl), &unsignedp, 0);
3952 SET_DECL_RTL (decl, gen_reg_rtx (reg_mode));
3954 if (!DECL_ARTIFICIAL (decl))
3955 mark_user_reg (DECL_RTL (decl));
3957 if (POINTER_TYPE_P (type))
3958 mark_reg_pointer (DECL_RTL (decl),
3959 TYPE_ALIGN (TREE_TYPE (TREE_TYPE (decl))));
3961 maybe_set_unchanging (DECL_RTL (decl), decl);
3963 /* If something wants our address, try to use ADDRESSOF. */
3964 if (TREE_ADDRESSABLE (decl))
3965 put_var_into_stack (decl, /*rescan=*/false);
3968 else if (TREE_CODE (DECL_SIZE_UNIT (decl)) == INTEGER_CST
3969 && ! (flag_stack_check && ! STACK_CHECK_BUILTIN
3970 && 0 < compare_tree_int (DECL_SIZE_UNIT (decl),
3971 STACK_CHECK_MAX_VAR_SIZE)))
3973 /* Variable of fixed size that goes on the stack. */
3978 /* If we previously made RTL for this decl, it must be an array
3979 whose size was determined by the initializer.
3980 The old address was a register; set that register now
3981 to the proper address. */
3982 if (DECL_RTL_SET_P (decl))
3984 if (GET_CODE (DECL_RTL (decl)) != MEM
3985 || GET_CODE (XEXP (DECL_RTL (decl), 0)) != REG)
3987 oldaddr = XEXP (DECL_RTL (decl), 0);
3990 /* Set alignment we actually gave this decl. */
3991 DECL_ALIGN (decl) = (DECL_MODE (decl) == BLKmode ? BIGGEST_ALIGNMENT
3992 : GET_MODE_BITSIZE (DECL_MODE (decl)));
3993 DECL_USER_ALIGN (decl) = 0;
3995 x = assign_temp (decl, 1, 1, 1);
3996 set_mem_attributes (x, decl, 1);
3997 SET_DECL_RTL (decl, x);
4001 addr = force_operand (XEXP (DECL_RTL (decl), 0), oldaddr);
4002 if (addr != oldaddr)
4003 emit_move_insn (oldaddr, addr);
4007 /* Dynamic-size object: must push space on the stack. */
4009 rtx address, size, x;
4011 /* Record the stack pointer on entry to block, if have
4012 not already done so. */
4013 do_pending_stack_adjust ();
4014 save_stack_pointer ();
4016 /* In function-at-a-time mode, variable_size doesn't expand this,
4018 if (TREE_CODE (type) == ARRAY_TYPE && TYPE_DOMAIN (type))
4019 expand_expr (TYPE_MAX_VALUE (TYPE_DOMAIN (type)),
4020 const0_rtx, VOIDmode, 0);
4022 /* Compute the variable's size, in bytes. */
4023 size = expand_expr (DECL_SIZE_UNIT (decl), NULL_RTX, VOIDmode, 0);
4026 /* Allocate space on the stack for the variable. Note that
4027 DECL_ALIGN says how the variable is to be aligned and we
4028 cannot use it to conclude anything about the alignment of
4030 address = allocate_dynamic_stack_space (size, NULL_RTX,
4031 TYPE_ALIGN (TREE_TYPE (decl)));
4033 /* Reference the variable indirect through that rtx. */
4034 x = gen_rtx_MEM (DECL_MODE (decl), address);
4035 set_mem_attributes (x, decl, 1);
4036 SET_DECL_RTL (decl, x);
4039 /* Indicate the alignment we actually gave this variable. */
4040 #ifdef STACK_BOUNDARY
4041 DECL_ALIGN (decl) = STACK_BOUNDARY;
4043 DECL_ALIGN (decl) = BIGGEST_ALIGNMENT;
4045 DECL_USER_ALIGN (decl) = 0;
4049 /* Emit code to perform the initialization of a declaration DECL. */
4052 expand_decl_init (decl)
4055 int was_used = TREE_USED (decl);
4057 /* If this is a CONST_DECL, we don't have to generate any code. Likewise
4058 for static decls. */
4059 if (TREE_CODE (decl) == CONST_DECL
4060 || TREE_STATIC (decl))
4063 /* Compute and store the initial value now. */
4067 if (DECL_INITIAL (decl) == error_mark_node)
4069 enum tree_code code = TREE_CODE (TREE_TYPE (decl));
4071 if (code == INTEGER_TYPE || code == REAL_TYPE || code == ENUMERAL_TYPE
4072 || code == POINTER_TYPE || code == REFERENCE_TYPE)
4073 expand_assignment (decl, convert (TREE_TYPE (decl), integer_zero_node),
4077 else if (DECL_INITIAL (decl) && TREE_CODE (DECL_INITIAL (decl)) != TREE_LIST)
4079 emit_line_note (DECL_SOURCE_FILE (decl), DECL_SOURCE_LINE (decl));
4080 expand_assignment (decl, DECL_INITIAL (decl), 0, 0);
4084 /* Don't let the initialization count as "using" the variable. */
4085 TREE_USED (decl) = was_used;
4087 /* Free any temporaries we made while initializing the decl. */
4088 preserve_temp_slots (NULL_RTX);
4093 /* CLEANUP is an expression to be executed at exit from this binding contour;
4094 for example, in C++, it might call the destructor for this variable.
4096 We wrap CLEANUP in an UNSAVE_EXPR node, so that we can expand the
4097 CLEANUP multiple times, and have the correct semantics. This
4098 happens in exception handling, for gotos, returns, breaks that
4099 leave the current scope.
4101 If CLEANUP is nonzero and DECL is zero, we record a cleanup
4102 that is not associated with any particular variable. */
4105 expand_decl_cleanup (decl, cleanup)
4108 struct nesting *thisblock;
4110 /* Error if we are not in any block. */
4111 if (cfun == 0 || block_stack == 0)
4114 thisblock = block_stack;
4116 /* Record the cleanup if there is one. */
4122 tree *cleanups = &thisblock->data.block.cleanups;
4123 int cond_context = conditional_context ();
4127 rtx flag = gen_reg_rtx (word_mode);
4132 emit_move_insn (flag, const0_rtx);
4133 set_flag_0 = get_insns ();
4136 thisblock->data.block.last_unconditional_cleanup
4137 = emit_insn_after (set_flag_0,
4138 thisblock->data.block.last_unconditional_cleanup);
4140 emit_move_insn (flag, const1_rtx);
4142 cond = build_decl (VAR_DECL, NULL_TREE,
4143 (*lang_hooks.types.type_for_mode) (word_mode, 1));
4144 SET_DECL_RTL (cond, flag);
4146 /* Conditionalize the cleanup. */
4147 cleanup = build (COND_EXPR, void_type_node,
4148 (*lang_hooks.truthvalue_conversion) (cond),
4149 cleanup, integer_zero_node);
4150 cleanup = fold (cleanup);
4152 cleanups = &thisblock->data.block.cleanups;
4155 cleanup = unsave_expr (cleanup);
4157 t = *cleanups = tree_cons (decl, cleanup, *cleanups);
4160 /* If this block has a cleanup, it belongs in stack_block_stack. */
4161 stack_block_stack = thisblock;
4168 if (! using_eh_for_cleanups_p)
4169 TREE_ADDRESSABLE (t) = 1;
4171 expand_eh_region_start ();
4178 thisblock->data.block.last_unconditional_cleanup
4179 = emit_insn_after (seq,
4180 thisblock->data.block.last_unconditional_cleanup);
4184 thisblock->data.block.last_unconditional_cleanup
4186 /* When we insert instructions after the last unconditional cleanup,
4187 we don't adjust last_insn. That means that a later add_insn will
4188 clobber the instructions we've just added. The easiest way to
4189 fix this is to just insert another instruction here, so that the
4190 instructions inserted after the last unconditional cleanup are
4191 never the last instruction. */
4192 emit_note (NOTE_INSN_DELETED);
4198 /* Like expand_decl_cleanup, but maybe only run the cleanup if an exception
4202 expand_decl_cleanup_eh (decl, cleanup, eh_only)
4206 int ret = expand_decl_cleanup (decl, cleanup);
4209 tree node = block_stack->data.block.cleanups;
4210 CLEANUP_EH_ONLY (node) = eh_only;
4215 /* DECL is an anonymous union. CLEANUP is a cleanup for DECL.
4216 DECL_ELTS is the list of elements that belong to DECL's type.
4217 In each, the TREE_VALUE is a VAR_DECL, and the TREE_PURPOSE a cleanup. */
4220 expand_anon_union_decl (decl, cleanup, decl_elts)
4221 tree decl, cleanup, decl_elts;
4223 struct nesting *thisblock = cfun == 0 ? 0 : block_stack;
4227 /* If any of the elements are addressable, so is the entire union. */
4228 for (t = decl_elts; t; t = TREE_CHAIN (t))
4229 if (TREE_ADDRESSABLE (TREE_VALUE (t)))
4231 TREE_ADDRESSABLE (decl) = 1;
4236 expand_decl_cleanup (decl, cleanup);
4237 x = DECL_RTL (decl);
4239 /* Go through the elements, assigning RTL to each. */
4240 for (t = decl_elts; t; t = TREE_CHAIN (t))
4242 tree decl_elt = TREE_VALUE (t);
4243 tree cleanup_elt = TREE_PURPOSE (t);
4244 enum machine_mode mode = TYPE_MODE (TREE_TYPE (decl_elt));
4246 /* If any of the elements are addressable, so is the entire
4248 if (TREE_USED (decl_elt))
4249 TREE_USED (decl) = 1;
4251 /* Propagate the union's alignment to the elements. */
4252 DECL_ALIGN (decl_elt) = DECL_ALIGN (decl);
4253 DECL_USER_ALIGN (decl_elt) = DECL_USER_ALIGN (decl);
4255 /* If the element has BLKmode and the union doesn't, the union is
4256 aligned such that the element doesn't need to have BLKmode, so
4257 change the element's mode to the appropriate one for its size. */
4258 if (mode == BLKmode && DECL_MODE (decl) != BLKmode)
4259 DECL_MODE (decl_elt) = mode
4260 = mode_for_size_tree (DECL_SIZE (decl_elt), MODE_INT, 1);
4262 /* (SUBREG (MEM ...)) at RTL generation time is invalid, so we
4263 instead create a new MEM rtx with the proper mode. */
4264 if (GET_CODE (x) == MEM)
4266 if (mode == GET_MODE (x))
4267 SET_DECL_RTL (decl_elt, x);
4269 SET_DECL_RTL (decl_elt, adjust_address_nv (x, mode, 0));
4271 else if (GET_CODE (x) == REG)
4273 if (mode == GET_MODE (x))
4274 SET_DECL_RTL (decl_elt, x);
4276 SET_DECL_RTL (decl_elt, gen_lowpart_SUBREG (mode, x));
4281 /* Record the cleanup if there is one. */
4284 thisblock->data.block.cleanups
4285 = tree_cons (decl_elt, cleanup_elt,
4286 thisblock->data.block.cleanups);
4290 /* Expand a list of cleanups LIST.
4291 Elements may be expressions or may be nested lists.
4293 If IN_FIXUP is nonzero, we are generating this cleanup for a fixup
4294 goto and handle protection regions specially in that case.
4296 If REACHABLE, we emit code, otherwise just inform the exception handling
4297 code about this finalization. */
4300 expand_cleanups (list, in_fixup, reachable)
4306 for (tail = list; tail; tail = TREE_CHAIN (tail))
4307 if (TREE_CODE (TREE_VALUE (tail)) == TREE_LIST)
4308 expand_cleanups (TREE_VALUE (tail), in_fixup, reachable);
4311 if (! in_fixup && using_eh_for_cleanups_p)
4312 expand_eh_region_end_cleanup (TREE_VALUE (tail));
4314 if (reachable && !CLEANUP_EH_ONLY (tail))
4316 /* Cleanups may be run multiple times. For example,
4317 when exiting a binding contour, we expand the
4318 cleanups associated with that contour. When a goto
4319 within that binding contour has a target outside that
4320 contour, it will expand all cleanups from its scope to
4321 the target. Though the cleanups are expanded multiple
4322 times, the control paths are non-overlapping so the
4323 cleanups will not be executed twice. */
4325 /* We may need to protect from outer cleanups. */
4326 if (in_fixup && using_eh_for_cleanups_p)
4328 expand_eh_region_start ();
4330 expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0);
4332 expand_eh_region_end_fixup (TREE_VALUE (tail));
4335 expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0);
4342 /* Mark when the context we are emitting RTL for as a conditional
4343 context, so that any cleanup actions we register with
4344 expand_decl_init will be properly conditionalized when those
4345 cleanup actions are later performed. Must be called before any
4346 expression (tree) is expanded that is within a conditional context. */
4349 start_cleanup_deferral ()
4351 /* block_stack can be NULL if we are inside the parameter list. It is
4352 OK to do nothing, because cleanups aren't possible here. */
4354 ++block_stack->data.block.conditional_code;
4357 /* Mark the end of a conditional region of code. Because cleanup
4358 deferrals may be nested, we may still be in a conditional region
4359 after we end the currently deferred cleanups, only after we end all
4360 deferred cleanups, are we back in unconditional code. */
4363 end_cleanup_deferral ()
4365 /* block_stack can be NULL if we are inside the parameter list. It is
4366 OK to do nothing, because cleanups aren't possible here. */
4368 --block_stack->data.block.conditional_code;
4372 last_cleanup_this_contour ()
4374 if (block_stack == 0)
4377 return block_stack->data.block.cleanups;
4380 /* Return 1 if there are any pending cleanups at this point.
4381 If THIS_CONTOUR is nonzero, check the current contour as well.
4382 Otherwise, look only at the contours that enclose this one. */
4385 any_pending_cleanups (this_contour)
4388 struct nesting *block;
4390 if (cfun == NULL || cfun->stmt == NULL || block_stack == 0)
4393 if (this_contour && block_stack->data.block.cleanups != NULL)
4395 if (block_stack->data.block.cleanups == 0
4396 && block_stack->data.block.outer_cleanups == 0)
4399 for (block = block_stack->next; block; block = block->next)
4400 if (block->data.block.cleanups != 0)
4406 /* Enter a case (Pascal) or switch (C) statement.
4407 Push a block onto case_stack and nesting_stack
4408 to accumulate the case-labels that are seen
4409 and to record the labels generated for the statement.
4411 EXIT_FLAG is nonzero if `exit_something' should exit this case stmt.
4412 Otherwise, this construct is transparent for `exit_something'.
4414 EXPR is the index-expression to be dispatched on.
4415 TYPE is its nominal type. We could simply convert EXPR to this type,
4416 but instead we take short cuts. */
4419 expand_start_case (exit_flag, expr, type, printname)
4423 const char *printname;
4425 struct nesting *thiscase = ALLOC_NESTING ();
4427 /* Make an entry on case_stack for the case we are entering. */
4429 thiscase->desc = CASE_NESTING;
4430 thiscase->next = case_stack;
4431 thiscase->all = nesting_stack;
4432 thiscase->depth = ++nesting_depth;
4433 thiscase->exit_label = exit_flag ? gen_label_rtx () : 0;
4434 thiscase->data.case_stmt.case_list = 0;
4435 thiscase->data.case_stmt.index_expr = expr;
4436 thiscase->data.case_stmt.nominal_type = type;
4437 thiscase->data.case_stmt.default_label = 0;
4438 thiscase->data.case_stmt.printname = printname;
4439 thiscase->data.case_stmt.line_number_status = force_line_numbers ();
4440 case_stack = thiscase;
4441 nesting_stack = thiscase;
4443 do_pending_stack_adjust ();
4446 /* Make sure case_stmt.start points to something that won't
4447 need any transformation before expand_end_case. */
4448 if (GET_CODE (get_last_insn ()) != NOTE)
4449 emit_note (NOTE_INSN_DELETED);
4451 thiscase->data.case_stmt.start = get_last_insn ();
4453 start_cleanup_deferral ();
4456 /* Start a "dummy case statement" within which case labels are invalid
4457 and are not connected to any larger real case statement.
4458 This can be used if you don't want to let a case statement jump
4459 into the middle of certain kinds of constructs. */
4462 expand_start_case_dummy ()
4464 struct nesting *thiscase = ALLOC_NESTING ();
4466 /* Make an entry on case_stack for the dummy. */
4468 thiscase->desc = CASE_NESTING;
4469 thiscase->next = case_stack;
4470 thiscase->all = nesting_stack;
4471 thiscase->depth = ++nesting_depth;
4472 thiscase->exit_label = 0;
4473 thiscase->data.case_stmt.case_list = 0;
4474 thiscase->data.case_stmt.start = 0;
4475 thiscase->data.case_stmt.nominal_type = 0;
4476 thiscase->data.case_stmt.default_label = 0;
4477 case_stack = thiscase;
4478 nesting_stack = thiscase;
4479 start_cleanup_deferral ();
4485 /* If this is the first label, warn if any insns have been emitted. */
4486 if (case_stack->data.case_stmt.line_number_status >= 0)
4490 restore_line_number_status
4491 (case_stack->data.case_stmt.line_number_status);
4492 case_stack->data.case_stmt.line_number_status = -1;
4494 for (insn = case_stack->data.case_stmt.start;
4496 insn = NEXT_INSN (insn))
4498 if (GET_CODE (insn) == CODE_LABEL)
4500 if (GET_CODE (insn) != NOTE
4501 && (GET_CODE (insn) != INSN || GET_CODE (PATTERN (insn)) != USE))
4504 insn = PREV_INSN (insn);
4505 while (insn && (GET_CODE (insn) != NOTE || NOTE_LINE_NUMBER (insn) < 0));
4507 /* If insn is zero, then there must have been a syntax error. */
4511 locus.file = NOTE_SOURCE_FILE (insn);
4512 locus.line = NOTE_LINE_NUMBER (insn);
4513 warning ("%Hunreachable code at beginning of %s", &locus,
4514 case_stack->data.case_stmt.printname);
4522 /* Accumulate one case or default label inside a case or switch statement.
4523 VALUE is the value of the case (a null pointer, for a default label).
4524 The function CONVERTER, when applied to arguments T and V,
4525 converts the value V to the type T.
4527 If not currently inside a case or switch statement, return 1 and do
4528 nothing. The caller will print a language-specific error message.
4529 If VALUE is a duplicate or overlaps, return 2 and do nothing
4530 except store the (first) duplicate node in *DUPLICATE.
4531 If VALUE is out of range, return 3 and do nothing.
4532 If we are jumping into the scope of a cleanup or var-sized array, return 5.
4533 Return 0 on success.
4535 Extended to handle range statements. */
4538 pushcase (value, converter, label, duplicate)
4540 tree (*converter) PARAMS ((tree, tree));
4547 /* Fail if not inside a real case statement. */
4548 if (! (case_stack && case_stack->data.case_stmt.start))
4551 if (stack_block_stack
4552 && stack_block_stack->depth > case_stack->depth)
4555 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
4556 nominal_type = case_stack->data.case_stmt.nominal_type;
4558 /* If the index is erroneous, avoid more problems: pretend to succeed. */
4559 if (index_type == error_mark_node)
4562 /* Convert VALUE to the type in which the comparisons are nominally done. */
4564 value = (*converter) (nominal_type, value);
4568 /* Fail if this value is out of range for the actual type of the index
4569 (which may be narrower than NOMINAL_TYPE). */
4571 && (TREE_CONSTANT_OVERFLOW (value)
4572 || ! int_fits_type_p (value, index_type)))
4575 return add_case_node (value, value, label, duplicate);
4578 /* Like pushcase but this case applies to all values between VALUE1 and
4579 VALUE2 (inclusive). If VALUE1 is NULL, the range starts at the lowest
4580 value of the index type and ends at VALUE2. If VALUE2 is NULL, the range
4581 starts at VALUE1 and ends at the highest value of the index type.
4582 If both are NULL, this case applies to all values.
4584 The return value is the same as that of pushcase but there is one
4585 additional error code: 4 means the specified range was empty. */
4588 pushcase_range (value1, value2, converter, label, duplicate)
4589 tree value1, value2;
4590 tree (*converter) PARAMS ((tree, tree));
4597 /* Fail if not inside a real case statement. */
4598 if (! (case_stack && case_stack->data.case_stmt.start))
4601 if (stack_block_stack
4602 && stack_block_stack->depth > case_stack->depth)
4605 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
4606 nominal_type = case_stack->data.case_stmt.nominal_type;
4608 /* If the index is erroneous, avoid more problems: pretend to succeed. */
4609 if (index_type == error_mark_node)
4614 /* Convert VALUEs to type in which the comparisons are nominally done
4615 and replace any unspecified value with the corresponding bound. */
4617 value1 = TYPE_MIN_VALUE (index_type);
4619 value2 = TYPE_MAX_VALUE (index_type);
4621 /* Fail if the range is empty. Do this before any conversion since
4622 we want to allow out-of-range empty ranges. */
4623 if (value2 != 0 && tree_int_cst_lt (value2, value1))
4626 /* If the max was unbounded, use the max of the nominal_type we are
4627 converting to. Do this after the < check above to suppress false
4630 value2 = TYPE_MAX_VALUE (nominal_type);
4632 value1 = (*converter) (nominal_type, value1);
4633 value2 = (*converter) (nominal_type, value2);
4635 /* Fail if these values are out of range. */
4636 if (TREE_CONSTANT_OVERFLOW (value1)
4637 || ! int_fits_type_p (value1, index_type))
4640 if (TREE_CONSTANT_OVERFLOW (value2)
4641 || ! int_fits_type_p (value2, index_type))
4644 return add_case_node (value1, value2, label, duplicate);
4647 /* Do the actual insertion of a case label for pushcase and pushcase_range
4648 into case_stack->data.case_stmt.case_list. Use an AVL tree to avoid
4649 slowdown for large switch statements. */
4652 add_case_node (low, high, label, duplicate)
4657 struct case_node *p, **q, *r;
4659 /* If there's no HIGH value, then this is not a case range; it's
4660 just a simple case label. But that's just a degenerate case
4665 /* Handle default labels specially. */
4668 if (case_stack->data.case_stmt.default_label != 0)
4670 *duplicate = case_stack->data.case_stmt.default_label;
4673 case_stack->data.case_stmt.default_label = label;
4674 expand_label (label);
4678 q = &case_stack->data.case_stmt.case_list;
4685 /* Keep going past elements distinctly greater than HIGH. */
4686 if (tree_int_cst_lt (high, p->low))
4689 /* or distinctly less than LOW. */
4690 else if (tree_int_cst_lt (p->high, low))
4695 /* We have an overlap; this is an error. */
4696 *duplicate = p->code_label;
4701 /* Add this label to the chain, and succeed. */
4703 r = (struct case_node *) ggc_alloc (sizeof (struct case_node));
4706 /* If the bounds are equal, turn this into the one-value case. */
4707 if (tree_int_cst_equal (low, high))
4712 r->code_label = label;
4713 expand_label (label);
4723 struct case_node *s;
4729 if (! (b = p->balance))
4730 /* Growth propagation from left side. */
4737 if ((p->left = s = r->right))
4746 if ((r->parent = s))
4754 case_stack->data.case_stmt.case_list = r;
4757 /* r->balance == +1 */
4762 struct case_node *t = r->right;
4764 if ((p->left = s = t->right))
4768 if ((r->right = s = t->left))
4782 if ((t->parent = s))
4790 case_stack->data.case_stmt.case_list = t;
4797 /* p->balance == +1; growth of left side balances the node. */
4807 if (! (b = p->balance))
4808 /* Growth propagation from right side. */
4816 if ((p->right = s = r->left))
4824 if ((r->parent = s))
4833 case_stack->data.case_stmt.case_list = r;
4837 /* r->balance == -1 */
4841 struct case_node *t = r->left;
4843 if ((p->right = s = t->left))
4848 if ((r->left = s = t->right))
4862 if ((t->parent = s))
4871 case_stack->data.case_stmt.case_list = t;
4877 /* p->balance == -1; growth of right side balances the node. */
4890 /* Returns the number of possible values of TYPE.
4891 Returns -1 if the number is unknown, variable, or if the number does not
4892 fit in a HOST_WIDE_INT.
4893 Sets *SPARSENESS to 2 if TYPE is an ENUMERAL_TYPE whose values
4894 do not increase monotonically (there may be duplicates);
4895 to 1 if the values increase monotonically, but not always by 1;
4896 otherwise sets it to 0. */
4899 all_cases_count (type, sparseness)
4904 HOST_WIDE_INT count, minval, lastval;
4908 switch (TREE_CODE (type))
4915 count = 1 << BITS_PER_UNIT;
4920 if (TYPE_MAX_VALUE (type) != 0
4921 && 0 != (t = fold (build (MINUS_EXPR, type, TYPE_MAX_VALUE (type),
4922 TYPE_MIN_VALUE (type))))
4923 && 0 != (t = fold (build (PLUS_EXPR, type, t,
4924 convert (type, integer_zero_node))))
4925 && host_integerp (t, 1))
4926 count = tree_low_cst (t, 1);
4932 /* Don't waste time with enumeral types with huge values. */
4933 if (! host_integerp (TYPE_MIN_VALUE (type), 0)
4934 || TYPE_MAX_VALUE (type) == 0
4935 || ! host_integerp (TYPE_MAX_VALUE (type), 0))
4938 lastval = minval = tree_low_cst (TYPE_MIN_VALUE (type), 0);
4941 for (t = TYPE_VALUES (type); t != NULL_TREE; t = TREE_CHAIN (t))
4943 HOST_WIDE_INT thisval = tree_low_cst (TREE_VALUE (t), 0);
4945 if (*sparseness == 2 || thisval <= lastval)
4947 else if (thisval != minval + count)
4958 #define BITARRAY_TEST(ARRAY, INDEX) \
4959 ((ARRAY)[(unsigned) (INDEX) / HOST_BITS_PER_CHAR]\
4960 & (1 << ((unsigned) (INDEX) % HOST_BITS_PER_CHAR)))
4961 #define BITARRAY_SET(ARRAY, INDEX) \
4962 ((ARRAY)[(unsigned) (INDEX) / HOST_BITS_PER_CHAR]\
4963 |= 1 << ((unsigned) (INDEX) % HOST_BITS_PER_CHAR))
4965 /* Set the elements of the bitstring CASES_SEEN (which has length COUNT),
4966 with the case values we have seen, assuming the case expression
4968 SPARSENESS is as determined by all_cases_count.
4970 The time needed is proportional to COUNT, unless
4971 SPARSENESS is 2, in which case quadratic time is needed. */
4974 mark_seen_cases (type, cases_seen, count, sparseness)
4976 unsigned char *cases_seen;
4977 HOST_WIDE_INT count;
4980 tree next_node_to_try = NULL_TREE;
4981 HOST_WIDE_INT next_node_offset = 0;
4983 struct case_node *n, *root = case_stack->data.case_stmt.case_list;
4984 tree val = make_node (INTEGER_CST);
4986 TREE_TYPE (val) = type;
4990 else if (sparseness == 2)
4993 unsigned HOST_WIDE_INT xlo;
4995 /* This less efficient loop is only needed to handle
4996 duplicate case values (multiple enum constants
4997 with the same value). */
4998 TREE_TYPE (val) = TREE_TYPE (root->low);
4999 for (t = TYPE_VALUES (type), xlo = 0; t != NULL_TREE;
5000 t = TREE_CHAIN (t), xlo++)
5002 TREE_INT_CST_LOW (val) = TREE_INT_CST_LOW (TREE_VALUE (t));
5003 TREE_INT_CST_HIGH (val) = TREE_INT_CST_HIGH (TREE_VALUE (t));
5007 /* Keep going past elements distinctly greater than VAL. */
5008 if (tree_int_cst_lt (val, n->low))
5011 /* or distinctly less than VAL. */
5012 else if (tree_int_cst_lt (n->high, val))
5017 /* We have found a matching range. */
5018 BITARRAY_SET (cases_seen, xlo);
5028 case_stack->data.case_stmt.case_list = root = case_tree2list (root, 0);
5030 for (n = root; n; n = n->right)
5032 TREE_INT_CST_LOW (val) = TREE_INT_CST_LOW (n->low);
5033 TREE_INT_CST_HIGH (val) = TREE_INT_CST_HIGH (n->low);
5034 while (! tree_int_cst_lt (n->high, val))
5036 /* Calculate (into xlo) the "offset" of the integer (val).
5037 The element with lowest value has offset 0, the next smallest
5038 element has offset 1, etc. */
5040 unsigned HOST_WIDE_INT xlo;
5044 if (sparseness && TYPE_VALUES (type) != NULL_TREE)
5046 /* The TYPE_VALUES will be in increasing order, so
5047 starting searching where we last ended. */
5048 t = next_node_to_try;
5049 xlo = next_node_offset;
5055 t = TYPE_VALUES (type);
5058 if (tree_int_cst_equal (val, TREE_VALUE (t)))
5060 next_node_to_try = TREE_CHAIN (t);
5061 next_node_offset = xlo + 1;
5066 if (t == next_node_to_try)
5075 t = TYPE_MIN_VALUE (type);
5077 neg_double (TREE_INT_CST_LOW (t), TREE_INT_CST_HIGH (t),
5081 add_double (xlo, xhi,
5082 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val),
5086 if (xhi == 0 && xlo < (unsigned HOST_WIDE_INT) count)
5087 BITARRAY_SET (cases_seen, xlo);
5089 add_double (TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val),
5091 &TREE_INT_CST_LOW (val), &TREE_INT_CST_HIGH (val));
5097 /* Given a switch statement with an expression that is an enumeration
5098 type, warn if any of the enumeration type's literals are not
5099 covered by the case expressions of the switch. Also, warn if there
5100 are any extra switch cases that are *not* elements of the
5105 At one stage this function would: ``If all enumeration literals
5106 were covered by the case expressions, turn one of the expressions
5107 into the default expression since it should not be possible to fall
5108 through such a switch.''
5110 That code has since been removed as: ``This optimization is
5111 disabled because it causes valid programs to fail. ANSI C does not
5112 guarantee that an expression with enum type will have a value that
5113 is the same as one of the enumeration literals.'' */
5116 check_for_full_enumeration_handling (type)
5119 struct case_node *n;
5122 /* True iff the selector type is a numbered set mode. */
5125 /* The number of possible selector values. */
5128 /* For each possible selector value. a one iff it has been matched
5129 by a case value alternative. */
5130 unsigned char *cases_seen;
5132 /* The allocated size of cases_seen, in chars. */
5133 HOST_WIDE_INT bytes_needed;
5135 size = all_cases_count (type, &sparseness);
5136 bytes_needed = (size + HOST_BITS_PER_CHAR) / HOST_BITS_PER_CHAR;
5138 if (size > 0 && size < 600000
5139 /* We deliberately use calloc here, not cmalloc, so that we can suppress
5140 this optimization if we don't have enough memory rather than
5141 aborting, as xmalloc would do. */
5143 (unsigned char *) really_call_calloc (bytes_needed, 1)) != NULL)
5146 tree v = TYPE_VALUES (type);
5148 /* The time complexity of this code is normally O(N), where
5149 N being the number of members in the enumerated type.
5150 However, if type is an ENUMERAL_TYPE whose values do not
5151 increase monotonically, O(N*log(N)) time may be needed. */
5153 mark_seen_cases (type, cases_seen, size, sparseness);
5155 for (i = 0; v != NULL_TREE && i < size; i++, v = TREE_CHAIN (v))
5156 if (BITARRAY_TEST (cases_seen, i) == 0)
5157 warning ("enumeration value `%s' not handled in switch",
5158 IDENTIFIER_POINTER (TREE_PURPOSE (v)));
5163 /* Now we go the other way around; we warn if there are case
5164 expressions that don't correspond to enumerators. This can
5165 occur since C and C++ don't enforce type-checking of
5166 assignments to enumeration variables. */
5168 if (case_stack->data.case_stmt.case_list
5169 && case_stack->data.case_stmt.case_list->left)
5170 case_stack->data.case_stmt.case_list
5171 = case_tree2list (case_stack->data.case_stmt.case_list, 0);
5172 for (n = case_stack->data.case_stmt.case_list; n; n = n->right)
5174 for (chain = TYPE_VALUES (type);
5175 chain && !tree_int_cst_equal (n->low, TREE_VALUE (chain));
5176 chain = TREE_CHAIN (chain))
5181 if (TYPE_NAME (type) == 0)
5182 warning ("case value `%ld' not in enumerated type",
5183 (long) TREE_INT_CST_LOW (n->low));
5185 warning ("case value `%ld' not in enumerated type `%s'",
5186 (long) TREE_INT_CST_LOW (n->low),
5187 IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
5190 : DECL_NAME (TYPE_NAME (type))));
5192 if (!tree_int_cst_equal (n->low, n->high))
5194 for (chain = TYPE_VALUES (type);
5195 chain && !tree_int_cst_equal (n->high, TREE_VALUE (chain));
5196 chain = TREE_CHAIN (chain))
5201 if (TYPE_NAME (type) == 0)
5202 warning ("case value `%ld' not in enumerated type",
5203 (long) TREE_INT_CST_LOW (n->high));
5205 warning ("case value `%ld' not in enumerated type `%s'",
5206 (long) TREE_INT_CST_LOW (n->high),
5207 IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
5210 : DECL_NAME (TYPE_NAME (type))));
5217 /* Maximum number of case bit tests. */
5218 #define MAX_CASE_BIT_TESTS 3
5220 /* By default, enable case bit tests on targets with ashlsi3. */
5221 #ifndef CASE_USE_BIT_TESTS
5222 #define CASE_USE_BIT_TESTS (ashl_optab->handlers[word_mode].insn_code \
5223 != CODE_FOR_nothing)
5227 /* A case_bit_test represents a set of case nodes that may be
5228 selected from using a bit-wise comparison. HI and LO hold
5229 the integer to be tested against, LABEL contains the label
5230 to jump to upon success and BITS counts the number of case
5231 nodes handled by this test, typically the number of bits
5234 struct case_bit_test
5242 /* Determine whether "1 << x" is relatively cheap in word_mode. */
5244 static bool lshift_cheap_p ()
5246 static bool init = false;
5247 static bool cheap = true;
5251 rtx reg = gen_rtx_REG (word_mode, 10000);
5252 int cost = rtx_cost (gen_rtx_ASHIFT (word_mode, const1_rtx, reg), SET);
5253 cheap = cost < COSTS_N_INSNS (3);
5260 /* Comparison function for qsort to order bit tests by decreasing
5261 number of case nodes, i.e. the node with the most cases gets
5264 static int case_bit_test_cmp (p1, p2)
5268 const struct case_bit_test *d1 = p1;
5269 const struct case_bit_test *d2 = p2;
5271 return d2->bits - d1->bits;
5274 /* Expand a switch statement by a short sequence of bit-wise
5275 comparisons. "switch(x)" is effectively converted into
5276 "if ((1 << (x-MINVAL)) & CST)" where CST and MINVAL are
5279 INDEX_EXPR is the value being switched on, which is of
5280 type INDEX_TYPE. MINVAL is the lowest case value of in
5281 the case nodes, of INDEX_TYPE type, and RANGE is highest
5282 value minus MINVAL, also of type INDEX_TYPE. NODES is
5283 the set of case nodes, and DEFAULT_LABEL is the label to
5284 branch to should none of the cases match.
5286 There *MUST* be MAX_CASE_BIT_TESTS or less unique case
5290 emit_case_bit_tests (index_type, index_expr, minval, range,
5291 nodes, default_label)
5292 tree index_type, index_expr, minval, range;
5293 case_node_ptr nodes;
5296 struct case_bit_test test[MAX_CASE_BIT_TESTS];
5297 enum machine_mode mode;
5298 rtx expr, index, label;
5299 unsigned int i,j,lo,hi;
5300 struct case_node *n;
5304 for (n = nodes; n; n = n->right)
5306 label = label_rtx (n->code_label);
5307 for (i = 0; i < count; i++)
5308 if (same_case_target_p (label, test[i].label))
5313 if (count >= MAX_CASE_BIT_TESTS)
5317 test[i].label = label;
5324 lo = tree_low_cst (fold (build (MINUS_EXPR, index_type,
5325 n->low, minval)), 1);
5326 hi = tree_low_cst (fold (build (MINUS_EXPR, index_type,
5327 n->high, minval)), 1);
5328 for (j = lo; j <= hi; j++)
5329 if (j >= HOST_BITS_PER_WIDE_INT)
5330 test[i].hi |= (HOST_WIDE_INT) 1 << (j - HOST_BITS_PER_INT);
5332 test[i].lo |= (HOST_WIDE_INT) 1 << j;
5335 qsort (test, count, sizeof(*test), case_bit_test_cmp);
5337 index_expr = fold (build (MINUS_EXPR, index_type,
5338 convert (index_type, index_expr),
5339 convert (index_type, minval)));
5340 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
5342 index = protect_from_queue (index, 0);
5343 do_pending_stack_adjust ();
5345 mode = TYPE_MODE (index_type);
5346 expr = expand_expr (range, NULL_RTX, VOIDmode, 0);
5347 emit_cmp_and_jump_insns (index, expr, GTU, NULL_RTX, mode, 1,
5350 index = convert_to_mode (word_mode, index, 0);
5351 index = expand_binop (word_mode, ashl_optab, const1_rtx,
5352 index, NULL_RTX, 1, OPTAB_WIDEN);
5354 for (i = 0; i < count; i++)
5356 expr = immed_double_const (test[i].lo, test[i].hi, word_mode);
5357 expr = expand_binop (word_mode, and_optab, index, expr,
5358 NULL_RTX, 1, OPTAB_WIDEN);
5359 emit_cmp_and_jump_insns (expr, const0_rtx, NE, NULL_RTX,
5360 word_mode, 1, test[i].label);
5363 emit_jump (default_label);
5366 /* Terminate a case (Pascal) or switch (C) statement
5367 in which ORIG_INDEX is the expression to be tested.
5368 If ORIG_TYPE is not NULL, it is the original ORIG_INDEX
5369 type as given in the source before any compiler conversions.
5370 Generate the code to test it and jump to the right place. */
5373 expand_end_case_type (orig_index, orig_type)
5374 tree orig_index, orig_type;
5376 tree minval = NULL_TREE, maxval = NULL_TREE, range = NULL_TREE;
5377 rtx default_label = 0;
5378 struct case_node *n, *m;
5379 unsigned int count, uniq;
5385 rtx before_case, end, lab;
5386 struct nesting *thiscase = case_stack;
5387 tree index_expr, index_type;
5388 bool exit_done = false;
5391 /* Don't crash due to previous errors. */
5392 if (thiscase == NULL)
5395 index_expr = thiscase->data.case_stmt.index_expr;
5396 index_type = TREE_TYPE (index_expr);
5397 unsignedp = TREE_UNSIGNED (index_type);
5398 if (orig_type == NULL)
5399 orig_type = TREE_TYPE (orig_index);
5401 do_pending_stack_adjust ();
5403 /* This might get a spurious warning in the presence of a syntax error;
5404 it could be fixed by moving the call to check_seenlabel after the
5405 check for error_mark_node, and copying the code of check_seenlabel that
5406 deals with case_stack->data.case_stmt.line_number_status /
5407 restore_line_number_status in front of the call to end_cleanup_deferral;
5408 However, this might miss some useful warnings in the presence of
5409 non-syntax errors. */
5412 /* An ERROR_MARK occurs for various reasons including invalid data type. */
5413 if (index_type != error_mark_node)
5415 /* If the switch expression was an enumerated type, check that
5416 exactly all enumeration literals are covered by the cases.
5417 The check is made when -Wswitch was specified and there is no
5418 default case, or when -Wswitch-enum was specified. */
5419 if (((warn_switch && !thiscase->data.case_stmt.default_label)
5420 || warn_switch_enum)
5421 && TREE_CODE (orig_type) == ENUMERAL_TYPE
5422 && TREE_CODE (index_expr) != INTEGER_CST)
5423 check_for_full_enumeration_handling (orig_type);
5425 if (warn_switch_default && !thiscase->data.case_stmt.default_label)
5426 warning ("switch missing default case");
5428 /* If we don't have a default-label, create one here,
5429 after the body of the switch. */
5430 if (thiscase->data.case_stmt.default_label == 0)
5432 thiscase->data.case_stmt.default_label
5433 = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
5434 /* Share the exit label if possible. */
5435 if (thiscase->exit_label)
5437 SET_DECL_RTL (thiscase->data.case_stmt.default_label,
5438 thiscase->exit_label);
5441 expand_label (thiscase->data.case_stmt.default_label);
5443 default_label = label_rtx (thiscase->data.case_stmt.default_label);
5445 before_case = get_last_insn ();
5447 if (thiscase->data.case_stmt.case_list
5448 && thiscase->data.case_stmt.case_list->left)
5449 thiscase->data.case_stmt.case_list
5450 = case_tree2list (thiscase->data.case_stmt.case_list, 0);
5452 /* Simplify the case-list before we count it. */
5453 group_case_nodes (thiscase->data.case_stmt.case_list);
5454 strip_default_case_nodes (&thiscase->data.case_stmt.case_list,
5457 /* Get upper and lower bounds of case values.
5458 Also convert all the case values to the index expr's data type. */
5462 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5464 /* Check low and high label values are integers. */
5465 if (TREE_CODE (n->low) != INTEGER_CST)
5467 if (TREE_CODE (n->high) != INTEGER_CST)
5470 n->low = convert (index_type, n->low);
5471 n->high = convert (index_type, n->high);
5473 /* Count the elements and track the largest and smallest
5474 of them (treating them as signed even if they are not). */
5482 if (INT_CST_LT (n->low, minval))
5484 if (INT_CST_LT (maxval, n->high))
5487 /* A range counts double, since it requires two compares. */
5488 if (! tree_int_cst_equal (n->low, n->high))
5491 /* Count the number of unique case node targets. */
5493 lab = label_rtx (n->code_label);
5494 for (m = thiscase->data.case_stmt.case_list; m != n; m = m->right)
5495 if (same_case_target_p (label_rtx (m->code_label), lab))
5502 /* Compute span of values. */
5504 range = fold (build (MINUS_EXPR, index_type, maxval, minval));
5506 end_cleanup_deferral ();
5510 expand_expr (index_expr, const0_rtx, VOIDmode, 0);
5512 emit_jump (default_label);
5515 /* Try implementing this switch statement by a short sequence of
5516 bit-wise comparisons. However, we let the binary-tree case
5517 below handle constant index expressions. */
5518 else if (CASE_USE_BIT_TESTS
5519 && ! TREE_CONSTANT (index_expr)
5520 && compare_tree_int (range, GET_MODE_BITSIZE (word_mode)) < 0
5521 && compare_tree_int (range, 0) > 0
5522 && lshift_cheap_p ()
5523 && ((uniq == 1 && count >= 3)
5524 || (uniq == 2 && count >= 5)
5525 || (uniq == 3 && count >= 6)))
5527 /* Optimize the case where all the case values fit in a
5528 word without having to subtract MINVAL. In this case,
5529 we can optimize away the subtraction. */
5530 if (compare_tree_int (minval, 0) > 0
5531 && compare_tree_int (maxval, GET_MODE_BITSIZE (word_mode)) < 0)
5533 minval = integer_zero_node;
5536 emit_case_bit_tests (index_type, index_expr, minval, range,
5537 thiscase->data.case_stmt.case_list,
5541 /* If range of values is much bigger than number of values,
5542 make a sequence of conditional branches instead of a dispatch.
5543 If the switch-index is a constant, do it this way
5544 because we can optimize it. */
5546 else if (count < case_values_threshold ()
5547 || compare_tree_int (range, 10 * count) > 0
5548 /* RANGE may be signed, and really large ranges will show up
5549 as negative numbers. */
5550 || compare_tree_int (range, 0) < 0
5551 #ifndef ASM_OUTPUT_ADDR_DIFF_ELT
5554 || TREE_CONSTANT (index_expr))
5556 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
5558 /* If the index is a short or char that we do not have
5559 an insn to handle comparisons directly, convert it to
5560 a full integer now, rather than letting each comparison
5561 generate the conversion. */
5563 if (GET_MODE_CLASS (GET_MODE (index)) == MODE_INT
5564 && ! have_insn_for (COMPARE, GET_MODE (index)))
5566 enum machine_mode wider_mode;
5567 for (wider_mode = GET_MODE (index); wider_mode != VOIDmode;
5568 wider_mode = GET_MODE_WIDER_MODE (wider_mode))
5569 if (have_insn_for (COMPARE, wider_mode))
5571 index = convert_to_mode (wider_mode, index, unsignedp);
5577 do_pending_stack_adjust ();
5579 index = protect_from_queue (index, 0);
5580 if (GET_CODE (index) == MEM)
5581 index = copy_to_reg (index);
5582 if (GET_CODE (index) == CONST_INT
5583 || TREE_CODE (index_expr) == INTEGER_CST)
5585 /* Make a tree node with the proper constant value
5586 if we don't already have one. */
5587 if (TREE_CODE (index_expr) != INTEGER_CST)
5590 = build_int_2 (INTVAL (index),
5591 unsignedp || INTVAL (index) >= 0 ? 0 : -1);
5592 index_expr = convert (index_type, index_expr);
5595 /* For constant index expressions we need only
5596 issue an unconditional branch to the appropriate
5597 target code. The job of removing any unreachable
5598 code is left to the optimization phase if the
5599 "-O" option is specified. */
5600 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5601 if (! tree_int_cst_lt (index_expr, n->low)
5602 && ! tree_int_cst_lt (n->high, index_expr))
5606 emit_jump (label_rtx (n->code_label));
5608 emit_jump (default_label);
5612 /* If the index expression is not constant we generate
5613 a binary decision tree to select the appropriate
5614 target code. This is done as follows:
5616 The list of cases is rearranged into a binary tree,
5617 nearly optimal assuming equal probability for each case.
5619 The tree is transformed into RTL, eliminating
5620 redundant test conditions at the same time.
5622 If program flow could reach the end of the
5623 decision tree an unconditional jump to the
5624 default code is emitted. */
5627 = (TREE_CODE (orig_type) != ENUMERAL_TYPE
5628 && estimate_case_costs (thiscase->data.case_stmt.case_list));
5629 balance_case_nodes (&thiscase->data.case_stmt.case_list, NULL);
5630 emit_case_nodes (index, thiscase->data.case_stmt.case_list,
5631 default_label, index_type);
5632 emit_jump_if_reachable (default_label);
5637 table_label = gen_label_rtx ();
5638 if (! try_casesi (index_type, index_expr, minval, range,
5639 table_label, default_label))
5641 index_type = thiscase->data.case_stmt.nominal_type;
5643 /* Index jumptables from zero for suitable values of
5644 minval to avoid a subtraction. */
5646 && compare_tree_int (minval, 0) > 0
5647 && compare_tree_int (minval, 3) < 0)
5649 minval = integer_zero_node;
5653 if (! try_tablejump (index_type, index_expr, minval, range,
5654 table_label, default_label))
5658 /* Get table of labels to jump to, in order of case index. */
5660 ncases = tree_low_cst (range, 0) + 1;
5661 labelvec = (rtx *) alloca (ncases * sizeof (rtx));
5662 memset ((char *) labelvec, 0, ncases * sizeof (rtx));
5664 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5666 /* Compute the low and high bounds relative to the minimum
5667 value since that should fit in a HOST_WIDE_INT while the
5668 actual values may not. */
5670 = tree_low_cst (fold (build (MINUS_EXPR, index_type,
5671 n->low, minval)), 1);
5672 HOST_WIDE_INT i_high
5673 = tree_low_cst (fold (build (MINUS_EXPR, index_type,
5674 n->high, minval)), 1);
5677 for (i = i_low; i <= i_high; i ++)
5679 = gen_rtx_LABEL_REF (Pmode, label_rtx (n->code_label));
5682 /* Fill in the gaps with the default. */
5683 for (i = 0; i < ncases; i++)
5684 if (labelvec[i] == 0)
5685 labelvec[i] = gen_rtx_LABEL_REF (Pmode, default_label);
5687 /* Output the table. */
5688 emit_label (table_label);
5690 if (CASE_VECTOR_PC_RELATIVE || flag_pic)
5691 emit_jump_insn (gen_rtx_ADDR_DIFF_VEC (CASE_VECTOR_MODE,
5692 gen_rtx_LABEL_REF (Pmode, table_label),
5693 gen_rtvec_v (ncases, labelvec),
5694 const0_rtx, const0_rtx));
5696 emit_jump_insn (gen_rtx_ADDR_VEC (CASE_VECTOR_MODE,
5697 gen_rtvec_v (ncases, labelvec)));
5699 /* If the case insn drops through the table,
5700 after the table we must jump to the default-label.
5701 Otherwise record no drop-through after the table. */
5702 #ifdef CASE_DROPS_THROUGH
5703 emit_jump (default_label);
5709 before_case = NEXT_INSN (before_case);
5710 end = get_last_insn ();
5711 if (squeeze_notes (&before_case, &end))
5713 reorder_insns (before_case, end,
5714 thiscase->data.case_stmt.start);
5717 end_cleanup_deferral ();
5719 if (thiscase->exit_label && !exit_done)
5720 emit_label (thiscase->exit_label);
5722 POPSTACK (case_stack);
5727 /* Convert the tree NODE into a list linked by the right field, with the left
5728 field zeroed. RIGHT is used for recursion; it is a list to be placed
5729 rightmost in the resulting list. */
5731 static struct case_node *
5732 case_tree2list (node, right)
5733 struct case_node *node, *right;
5735 struct case_node *left;
5738 right = case_tree2list (node->right, right);
5740 node->right = right;
5741 if ((left = node->left))
5744 return case_tree2list (left, node);
5750 /* Generate code to jump to LABEL if OP1 and OP2 are equal. */
5753 do_jump_if_equal (op1, op2, label, unsignedp)
5754 rtx op1, op2, label;
5757 if (GET_CODE (op1) == CONST_INT && GET_CODE (op2) == CONST_INT)
5763 emit_cmp_and_jump_insns (op1, op2, EQ, NULL_RTX,
5764 (GET_MODE (op1) == VOIDmode
5765 ? GET_MODE (op2) : GET_MODE (op1)),
5769 /* Not all case values are encountered equally. This function
5770 uses a heuristic to weight case labels, in cases where that
5771 looks like a reasonable thing to do.
5773 Right now, all we try to guess is text, and we establish the
5776 chars above space: 16
5785 If we find any cases in the switch that are not either -1 or in the range
5786 of valid ASCII characters, or are control characters other than those
5787 commonly used with "\", don't treat this switch scanning text.
5789 Return 1 if these nodes are suitable for cost estimation, otherwise
5793 estimate_case_costs (node)
5796 tree min_ascii = integer_minus_one_node;
5797 tree max_ascii = convert (TREE_TYPE (node->high), build_int_2 (127, 0));
5801 /* If we haven't already made the cost table, make it now. Note that the
5802 lower bound of the table is -1, not zero. */
5804 if (! cost_table_initialized)
5806 cost_table_initialized = 1;
5808 for (i = 0; i < 128; i++)
5811 COST_TABLE (i) = 16;
5812 else if (ISPUNCT (i))
5814 else if (ISCNTRL (i))
5815 COST_TABLE (i) = -1;
5818 COST_TABLE (' ') = 8;
5819 COST_TABLE ('\t') = 4;
5820 COST_TABLE ('\0') = 4;
5821 COST_TABLE ('\n') = 2;
5822 COST_TABLE ('\f') = 1;
5823 COST_TABLE ('\v') = 1;
5824 COST_TABLE ('\b') = 1;
5827 /* See if all the case expressions look like text. It is text if the
5828 constant is >= -1 and the highest constant is <= 127. Do all comparisons
5829 as signed arithmetic since we don't want to ever access cost_table with a
5830 value less than -1. Also check that none of the constants in a range
5831 are strange control characters. */
5833 for (n = node; n; n = n->right)
5835 if ((INT_CST_LT (n->low, min_ascii)) || INT_CST_LT (max_ascii, n->high))
5838 for (i = (HOST_WIDE_INT) TREE_INT_CST_LOW (n->low);
5839 i <= (HOST_WIDE_INT) TREE_INT_CST_LOW (n->high); i++)
5840 if (COST_TABLE (i) < 0)
5844 /* All interesting values are within the range of interesting
5845 ASCII characters. */
5849 /* Determine whether two case labels branch to the same target. */
5852 same_case_target_p (l1, l2)
5860 i1 = next_real_insn (l1);
5861 i2 = next_real_insn (l2);
5865 if (i1 && simplejump_p (i1))
5867 l1 = XEXP (SET_SRC (PATTERN (i1)), 0);
5870 if (i2 && simplejump_p (i2))
5872 l2 = XEXP (SET_SRC (PATTERN (i2)), 0);
5877 /* Delete nodes that branch to the default label from a list of
5878 case nodes. Eg. case 5: default: becomes just default: */
5881 strip_default_case_nodes (prev, deflab)
5882 case_node_ptr *prev;
5890 if (same_case_target_p (label_rtx (ptr->code_label), deflab))
5897 /* Scan an ordered list of case nodes
5898 combining those with consecutive values or ranges.
5900 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
5903 group_case_nodes (head)
5906 case_node_ptr node = head;
5910 rtx lab = label_rtx (node->code_label);
5911 case_node_ptr np = node;
5913 /* Try to group the successors of NODE with NODE. */
5914 while (((np = np->right) != 0)
5915 /* Do they jump to the same place? */
5916 && same_case_target_p (label_rtx (np->code_label), lab)
5917 /* Are their ranges consecutive? */
5918 && tree_int_cst_equal (np->low,
5919 fold (build (PLUS_EXPR,
5920 TREE_TYPE (node->high),
5923 /* An overflow is not consecutive. */
5924 && tree_int_cst_lt (node->high,
5925 fold (build (PLUS_EXPR,
5926 TREE_TYPE (node->high),
5928 integer_one_node))))
5930 node->high = np->high;
5932 /* NP is the first node after NODE which can't be grouped with it.
5933 Delete the nodes in between, and move on to that node. */
5939 /* Take an ordered list of case nodes
5940 and transform them into a near optimal binary tree,
5941 on the assumption that any target code selection value is as
5942 likely as any other.
5944 The transformation is performed by splitting the ordered
5945 list into two equal sections plus a pivot. The parts are
5946 then attached to the pivot as left and right branches. Each
5947 branch is then transformed recursively. */
5950 balance_case_nodes (head, parent)
5951 case_node_ptr *head;
5952 case_node_ptr parent;
5965 /* Count the number of entries on branch. Also count the ranges. */
5969 if (!tree_int_cst_equal (np->low, np->high))
5973 cost += COST_TABLE (TREE_INT_CST_LOW (np->high));
5977 cost += COST_TABLE (TREE_INT_CST_LOW (np->low));
5985 /* Split this list if it is long enough for that to help. */
5990 /* Find the place in the list that bisects the list's total cost,
5991 Here I gets half the total cost. */
5996 /* Skip nodes while their cost does not reach that amount. */
5997 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
5998 i -= COST_TABLE (TREE_INT_CST_LOW ((*npp)->high));
5999 i -= COST_TABLE (TREE_INT_CST_LOW ((*npp)->low));
6002 npp = &(*npp)->right;
6007 /* Leave this branch lopsided, but optimize left-hand
6008 side and fill in `parent' fields for right-hand side. */
6010 np->parent = parent;
6011 balance_case_nodes (&np->left, np);
6012 for (; np->right; np = np->right)
6013 np->right->parent = np;
6017 /* If there are just three nodes, split at the middle one. */
6019 npp = &(*npp)->right;
6022 /* Find the place in the list that bisects the list's total cost,
6023 where ranges count as 2.
6024 Here I gets half the total cost. */
6025 i = (i + ranges + 1) / 2;
6028 /* Skip nodes while their cost does not reach that amount. */
6029 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
6034 npp = &(*npp)->right;
6039 np->parent = parent;
6042 /* Optimize each of the two split parts. */
6043 balance_case_nodes (&np->left, np);
6044 balance_case_nodes (&np->right, np);
6048 /* Else leave this branch as one level,
6049 but fill in `parent' fields. */
6051 np->parent = parent;
6052 for (; np->right; np = np->right)
6053 np->right->parent = np;
6058 /* Search the parent sections of the case node tree
6059 to see if a test for the lower bound of NODE would be redundant.
6060 INDEX_TYPE is the type of the index expression.
6062 The instructions to generate the case decision tree are
6063 output in the same order as nodes are processed so it is
6064 known that if a parent node checks the range of the current
6065 node minus one that the current node is bounded at its lower
6066 span. Thus the test would be redundant. */
6069 node_has_low_bound (node, index_type)
6074 case_node_ptr pnode;
6076 /* If the lower bound of this node is the lowest value in the index type,
6077 we need not test it. */
6079 if (tree_int_cst_equal (node->low, TYPE_MIN_VALUE (index_type)))
6082 /* If this node has a left branch, the value at the left must be less
6083 than that at this node, so it cannot be bounded at the bottom and
6084 we need not bother testing any further. */
6089 low_minus_one = fold (build (MINUS_EXPR, TREE_TYPE (node->low),
6090 node->low, integer_one_node));
6092 /* If the subtraction above overflowed, we can't verify anything.
6093 Otherwise, look for a parent that tests our value - 1. */
6095 if (! tree_int_cst_lt (low_minus_one, node->low))
6098 for (pnode = node->parent; pnode; pnode = pnode->parent)
6099 if (tree_int_cst_equal (low_minus_one, pnode->high))
6105 /* Search the parent sections of the case node tree
6106 to see if a test for the upper bound of NODE would be redundant.
6107 INDEX_TYPE is the type of the index expression.
6109 The instructions to generate the case decision tree are
6110 output in the same order as nodes are processed so it is
6111 known that if a parent node checks the range of the current
6112 node plus one that the current node is bounded at its upper
6113 span. Thus the test would be redundant. */
6116 node_has_high_bound (node, index_type)
6121 case_node_ptr pnode;
6123 /* If there is no upper bound, obviously no test is needed. */
6125 if (TYPE_MAX_VALUE (index_type) == NULL)
6128 /* If the upper bound of this node is the highest value in the type
6129 of the index expression, we need not test against it. */
6131 if (tree_int_cst_equal (node->high, TYPE_MAX_VALUE (index_type)))
6134 /* If this node has a right branch, the value at the right must be greater
6135 than that at this node, so it cannot be bounded at the top and
6136 we need not bother testing any further. */
6141 high_plus_one = fold (build (PLUS_EXPR, TREE_TYPE (node->high),
6142 node->high, integer_one_node));
6144 /* If the addition above overflowed, we can't verify anything.
6145 Otherwise, look for a parent that tests our value + 1. */
6147 if (! tree_int_cst_lt (node->high, high_plus_one))
6150 for (pnode = node->parent; pnode; pnode = pnode->parent)
6151 if (tree_int_cst_equal (high_plus_one, pnode->low))
6157 /* Search the parent sections of the
6158 case node tree to see if both tests for the upper and lower
6159 bounds of NODE would be redundant. */
6162 node_is_bounded (node, index_type)
6166 return (node_has_low_bound (node, index_type)
6167 && node_has_high_bound (node, index_type));
6170 /* Emit an unconditional jump to LABEL unless it would be dead code. */
6173 emit_jump_if_reachable (label)
6176 if (GET_CODE (get_last_insn ()) != BARRIER)
6180 /* Emit step-by-step code to select a case for the value of INDEX.
6181 The thus generated decision tree follows the form of the
6182 case-node binary tree NODE, whose nodes represent test conditions.
6183 INDEX_TYPE is the type of the index of the switch.
6185 Care is taken to prune redundant tests from the decision tree
6186 by detecting any boundary conditions already checked by
6187 emitted rtx. (See node_has_high_bound, node_has_low_bound
6188 and node_is_bounded, above.)
6190 Where the test conditions can be shown to be redundant we emit
6191 an unconditional jump to the target code. As a further
6192 optimization, the subordinates of a tree node are examined to
6193 check for bounded nodes. In this case conditional and/or
6194 unconditional jumps as a result of the boundary check for the
6195 current node are arranged to target the subordinates associated
6196 code for out of bound conditions on the current node.
6198 We can assume that when control reaches the code generated here,
6199 the index value has already been compared with the parents
6200 of this node, and determined to be on the same side of each parent
6201 as this node is. Thus, if this node tests for the value 51,
6202 and a parent tested for 52, we don't need to consider
6203 the possibility of a value greater than 51. If another parent
6204 tests for the value 50, then this node need not test anything. */
6207 emit_case_nodes (index, node, default_label, index_type)
6213 /* If INDEX has an unsigned type, we must make unsigned branches. */
6214 int unsignedp = TREE_UNSIGNED (index_type);
6215 enum machine_mode mode = GET_MODE (index);
6216 enum machine_mode imode = TYPE_MODE (index_type);
6218 /* See if our parents have already tested everything for us.
6219 If they have, emit an unconditional jump for this node. */
6220 if (node_is_bounded (node, index_type))
6221 emit_jump (label_rtx (node->code_label));
6223 else if (tree_int_cst_equal (node->low, node->high))
6225 /* Node is single valued. First see if the index expression matches
6226 this node and then check our children, if any. */
6228 do_jump_if_equal (index,
6229 convert_modes (mode, imode,
6230 expand_expr (node->low, NULL_RTX,
6233 label_rtx (node->code_label), unsignedp);
6235 if (node->right != 0 && node->left != 0)
6237 /* This node has children on both sides.
6238 Dispatch to one side or the other
6239 by comparing the index value with this node's value.
6240 If one subtree is bounded, check that one first,
6241 so we can avoid real branches in the tree. */
6243 if (node_is_bounded (node->right, index_type))
6245 emit_cmp_and_jump_insns (index,
6248 expand_expr (node->high, NULL_RTX,
6251 GT, NULL_RTX, mode, unsignedp,
6252 label_rtx (node->right->code_label));
6253 emit_case_nodes (index, node->left, default_label, index_type);
6256 else if (node_is_bounded (node->left, index_type))
6258 emit_cmp_and_jump_insns (index,
6261 expand_expr (node->high, NULL_RTX,
6264 LT, NULL_RTX, mode, unsignedp,
6265 label_rtx (node->left->code_label));
6266 emit_case_nodes (index, node->right, default_label, index_type);
6271 /* Neither node is bounded. First distinguish the two sides;
6272 then emit the code for one side at a time. */
6274 tree test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
6276 /* See if the value is on the right. */
6277 emit_cmp_and_jump_insns (index,
6280 expand_expr (node->high, NULL_RTX,
6283 GT, NULL_RTX, mode, unsignedp,
6284 label_rtx (test_label));
6286 /* Value must be on the left.
6287 Handle the left-hand subtree. */
6288 emit_case_nodes (index, node->left, default_label, index_type);
6289 /* If left-hand subtree does nothing,
6291 emit_jump_if_reachable (default_label);
6293 /* Code branches here for the right-hand subtree. */
6294 expand_label (test_label);
6295 emit_case_nodes (index, node->right, default_label, index_type);
6299 else if (node->right != 0 && node->left == 0)
6301 /* Here we have a right child but no left so we issue conditional
6302 branch to default and process the right child.
6304 Omit the conditional branch to default if we it avoid only one
6305 right child; it costs too much space to save so little time. */
6307 if (node->right->right || node->right->left
6308 || !tree_int_cst_equal (node->right->low, node->right->high))
6310 if (!node_has_low_bound (node, index_type))
6312 emit_cmp_and_jump_insns (index,
6315 expand_expr (node->high, NULL_RTX,
6318 LT, NULL_RTX, mode, unsignedp,
6322 emit_case_nodes (index, node->right, default_label, index_type);
6325 /* We cannot process node->right normally
6326 since we haven't ruled out the numbers less than
6327 this node's value. So handle node->right explicitly. */
6328 do_jump_if_equal (index,
6331 expand_expr (node->right->low, NULL_RTX,
6334 label_rtx (node->right->code_label), unsignedp);
6337 else if (node->right == 0 && node->left != 0)
6339 /* Just one subtree, on the left. */
6340 if (node->left->left || node->left->right
6341 || !tree_int_cst_equal (node->left->low, node->left->high))
6343 if (!node_has_high_bound (node, index_type))
6345 emit_cmp_and_jump_insns (index,
6348 expand_expr (node->high, NULL_RTX,
6351 GT, NULL_RTX, mode, unsignedp,
6355 emit_case_nodes (index, node->left, default_label, index_type);
6358 /* We cannot process node->left normally
6359 since we haven't ruled out the numbers less than
6360 this node's value. So handle node->left explicitly. */
6361 do_jump_if_equal (index,
6364 expand_expr (node->left->low, NULL_RTX,
6367 label_rtx (node->left->code_label), unsignedp);
6372 /* Node is a range. These cases are very similar to those for a single
6373 value, except that we do not start by testing whether this node
6374 is the one to branch to. */
6376 if (node->right != 0 && node->left != 0)
6378 /* Node has subtrees on both sides.
6379 If the right-hand subtree is bounded,
6380 test for it first, since we can go straight there.
6381 Otherwise, we need to make a branch in the control structure,
6382 then handle the two subtrees. */
6383 tree test_label = 0;
6385 if (node_is_bounded (node->right, index_type))
6386 /* Right hand node is fully bounded so we can eliminate any
6387 testing and branch directly to the target code. */
6388 emit_cmp_and_jump_insns (index,
6391 expand_expr (node->high, NULL_RTX,
6394 GT, NULL_RTX, mode, unsignedp,
6395 label_rtx (node->right->code_label));
6398 /* Right hand node requires testing.
6399 Branch to a label where we will handle it later. */
6401 test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
6402 emit_cmp_and_jump_insns (index,
6405 expand_expr (node->high, NULL_RTX,
6408 GT, NULL_RTX, mode, unsignedp,
6409 label_rtx (test_label));
6412 /* Value belongs to this node or to the left-hand subtree. */
6414 emit_cmp_and_jump_insns (index,
6417 expand_expr (node->low, NULL_RTX,
6420 GE, NULL_RTX, mode, unsignedp,
6421 label_rtx (node->code_label));
6423 /* Handle the left-hand subtree. */
6424 emit_case_nodes (index, node->left, default_label, index_type);
6426 /* If right node had to be handled later, do that now. */
6430 /* If the left-hand subtree fell through,
6431 don't let it fall into the right-hand subtree. */
6432 emit_jump_if_reachable (default_label);
6434 expand_label (test_label);
6435 emit_case_nodes (index, node->right, default_label, index_type);
6439 else if (node->right != 0 && node->left == 0)
6441 /* Deal with values to the left of this node,
6442 if they are possible. */
6443 if (!node_has_low_bound (node, index_type))
6445 emit_cmp_and_jump_insns (index,
6448 expand_expr (node->low, NULL_RTX,
6451 LT, NULL_RTX, mode, unsignedp,
6455 /* Value belongs to this node or to the right-hand subtree. */
6457 emit_cmp_and_jump_insns (index,
6460 expand_expr (node->high, NULL_RTX,
6463 LE, NULL_RTX, mode, unsignedp,
6464 label_rtx (node->code_label));
6466 emit_case_nodes (index, node->right, default_label, index_type);
6469 else if (node->right == 0 && node->left != 0)
6471 /* Deal with values to the right of this node,
6472 if they are possible. */
6473 if (!node_has_high_bound (node, index_type))
6475 emit_cmp_and_jump_insns (index,
6478 expand_expr (node->high, NULL_RTX,
6481 GT, NULL_RTX, mode, unsignedp,
6485 /* Value belongs to this node or to the left-hand subtree. */
6487 emit_cmp_and_jump_insns (index,
6490 expand_expr (node->low, NULL_RTX,
6493 GE, NULL_RTX, mode, unsignedp,
6494 label_rtx (node->code_label));
6496 emit_case_nodes (index, node->left, default_label, index_type);
6501 /* Node has no children so we check low and high bounds to remove
6502 redundant tests. Only one of the bounds can exist,
6503 since otherwise this node is bounded--a case tested already. */
6504 int high_bound = node_has_high_bound (node, index_type);
6505 int low_bound = node_has_low_bound (node, index_type);
6507 if (!high_bound && low_bound)
6509 emit_cmp_and_jump_insns (index,
6512 expand_expr (node->high, NULL_RTX,
6515 GT, NULL_RTX, mode, unsignedp,
6519 else if (!low_bound && high_bound)
6521 emit_cmp_and_jump_insns (index,
6524 expand_expr (node->low, NULL_RTX,
6527 LT, NULL_RTX, mode, unsignedp,
6530 else if (!low_bound && !high_bound)
6532 /* Widen LOW and HIGH to the same width as INDEX. */
6533 tree type = (*lang_hooks.types.type_for_mode) (mode, unsignedp);
6534 tree low = build1 (CONVERT_EXPR, type, node->low);
6535 tree high = build1 (CONVERT_EXPR, type, node->high);
6536 rtx low_rtx, new_index, new_bound;
6538 /* Instead of doing two branches, emit one unsigned branch for
6539 (index-low) > (high-low). */
6540 low_rtx = expand_expr (low, NULL_RTX, mode, 0);
6541 new_index = expand_simple_binop (mode, MINUS, index, low_rtx,
6542 NULL_RTX, unsignedp,
6544 new_bound = expand_expr (fold (build (MINUS_EXPR, type,
6548 emit_cmp_and_jump_insns (new_index, new_bound, GT, NULL_RTX,
6549 mode, 1, default_label);
6552 emit_jump (label_rtx (node->code_label));
6557 #include "gt-stmt.h"