1 /* Expands front end tree to back end RTL for GCC
2 Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997,
3 1998, 1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
22 /* This file handles the generation of rtl code from tree structure
23 above the level of expressions, using subroutines in exp*.c and emit-rtl.c.
24 It also creates the rtl expressions for parameters and auto variables
25 and has full responsibility for allocating stack slots.
27 The functions whose names start with `expand_' are called by the
28 parser to generate RTL instructions for various kinds of constructs.
30 Some control and binding constructs require calling several such
31 functions at different times. For example, a simple if-then
32 is expanded by calling `expand_start_cond' (with the condition-expression
33 as argument) before parsing the then-clause and calling `expand_end_cond'
34 after parsing the then-clause. */
38 #include "coretypes.h"
47 #include "insn-config.h"
50 #include "hard-reg-set.h"
57 #include "langhooks.h"
62 /* Assume that case vectors are not pc-relative. */
63 #ifndef CASE_VECTOR_PC_RELATIVE
64 #define CASE_VECTOR_PC_RELATIVE 0
67 /* Functions and data structures for expanding case statements. */
69 /* Case label structure, used to hold info on labels within case
70 statements. We handle "range" labels; for a single-value label
71 as in C, the high and low limits are the same.
73 An AVL tree of case nodes is initially created, and later transformed
74 to a list linked via the RIGHT fields in the nodes. Nodes with
75 higher case values are later in the list.
77 Switch statements can be output in one of two forms. A branch table
78 is used if there are more than a few labels and the labels are dense
79 within the range between the smallest and largest case value. If a
80 branch table is used, no further manipulations are done with the case
83 The alternative to the use of a branch table is to generate a series
84 of compare and jump insns. When that is done, we use the LEFT, RIGHT,
85 and PARENT fields to hold a binary tree. Initially the tree is
86 totally unbalanced, with everything on the right. We balance the tree
87 with nodes on the left having lower case values than the parent
88 and nodes on the right having higher values. We then output the tree
91 struct case_node GTY(())
93 struct case_node *left; /* Left son in binary tree */
94 struct case_node *right; /* Right son in binary tree; also node chain */
95 struct case_node *parent; /* Parent of node in binary tree */
96 tree low; /* Lowest index value for this label */
97 tree high; /* Highest index value for this label */
98 tree code_label; /* Label to jump to when node matches */
102 typedef struct case_node case_node;
103 typedef struct case_node *case_node_ptr;
105 /* These are used by estimate_case_costs and balance_case_nodes. */
107 /* This must be a signed type, and non-ANSI compilers lack signed char. */
108 static short cost_table_[129];
109 static int use_cost_table;
110 static int cost_table_initialized;
112 /* Special care is needed because we allow -1, but TREE_INT_CST_LOW
114 #define COST_TABLE(I) cost_table_[(unsigned HOST_WIDE_INT) ((I) + 1)]
116 /* Stack of control and binding constructs we are currently inside.
118 These constructs begin when you call `expand_start_WHATEVER'
119 and end when you call `expand_end_WHATEVER'. This stack records
120 info about how the construct began that tells the end-function
121 what to do. It also may provide information about the construct
122 to alter the behavior of other constructs within the body.
123 For example, they may affect the behavior of C `break' and `continue'.
125 Each construct gets one `struct nesting' object.
126 All of these objects are chained through the `all' field.
127 `nesting_stack' points to the first object (innermost construct).
128 The position of an entry on `nesting_stack' is in its `depth' field.
130 Each type of construct has its own individual stack.
131 For example, loops have `loop_stack'. Each object points to the
132 next object of the same type through the `next' field.
134 Some constructs are visible to `break' exit-statements and others
135 are not. Which constructs are visible depends on the language.
136 Therefore, the data structure allows each construct to be visible
137 or not, according to the args given when the construct is started.
138 The construct is visible if the `exit_label' field is non-null.
139 In that case, the value should be a CODE_LABEL rtx. */
141 struct nesting GTY(())
144 struct nesting *next;
155 /* For conds (if-then and if-then-else statements). */
158 /* Label for the end of the if construct.
159 There is none if EXITFLAG was not set
160 and no `else' has been seen yet. */
162 /* Label for the end of this alternative.
163 This may be the end of the if or the next else/elseif. */
165 } GTY ((tag ("COND_NESTING"))) cond;
169 /* Label at the top of the loop; place to loop back to. */
171 /* Label at the end of the whole construct. */
173 /* Label for `continue' statement to jump to;
174 this is in front of the stepper of the loop. */
176 } GTY ((tag ("LOOP_NESTING"))) loop;
177 /* For variable binding contours. */
180 /* Sequence number of this binding contour within the function,
181 in order of entry. */
182 int block_start_count;
183 /* Nonzero => value to restore stack to on exit. */
185 /* The NOTE that starts this contour.
186 Used by expand_goto to check whether the destination
187 is within each contour or not. */
189 /* Innermost containing binding contour that has a stack level. */
190 struct nesting *innermost_stack_block;
191 /* List of cleanups to be run on exit from this contour.
192 This is a list of expressions to be evaluated.
193 The TREE_PURPOSE of each link is the ..._DECL node
194 which the cleanup pertains to. */
196 /* List of cleanup-lists of blocks containing this block,
197 as they were at the locus where this block appears.
198 There is an element for each containing block,
199 ordered innermost containing block first.
200 The tail of this list can be 0,
201 if all remaining elements would be empty lists.
202 The element's TREE_VALUE is the cleanup-list of that block,
203 which may be null. */
205 /* Chain of labels defined inside this binding contour.
206 For contours that have stack levels or cleanups. */
207 struct label_chain *label_chain;
208 /* Nonzero if this is associated with an EH region. */
209 int exception_region;
210 /* The saved target_temp_slot_level from our outer block.
211 We may reset target_temp_slot_level to be the level of
212 this block, if that is done, target_temp_slot_level
213 reverts to the saved target_temp_slot_level at the very
215 int block_target_temp_slot_level;
216 /* True if we are currently emitting insns in an area of
217 output code that is controlled by a conditional
218 expression. This is used by the cleanup handling code to
219 generate conditional cleanup actions. */
220 int conditional_code;
221 /* A place to move the start of the exception region for any
222 of the conditional cleanups, must be at the end or after
223 the start of the last unconditional cleanup, and before any
224 conditional branch points. */
225 rtx last_unconditional_cleanup;
226 } GTY ((tag ("BLOCK_NESTING"))) block;
227 /* For switch (C) or case (Pascal) statements,
228 and also for dummies (see `expand_start_case_dummy'). */
231 /* The insn after which the case dispatch should finally
232 be emitted. Zero for a dummy. */
234 /* A list of case labels; it is first built as an AVL tree.
235 During expand_end_case, this is converted to a list, and may be
236 rearranged into a nearly balanced binary tree. */
237 struct case_node *case_list;
238 /* Label to jump to if no case matches. */
240 /* The expression to be dispatched on. */
242 /* Type that INDEX_EXPR should be converted to. */
244 /* Name of this kind of statement, for warnings. */
245 const char *printname;
246 /* Used to save no_line_numbers till we see the first case label.
247 We set this to -1 when we see the first case label in this
249 int line_number_status;
250 } GTY ((tag ("CASE_NESTING"))) case_stmt;
251 } GTY ((desc ("%1.desc"))) data;
254 /* Allocate and return a new `struct nesting'. */
256 #define ALLOC_NESTING() ggc_alloc (sizeof (struct nesting))
258 /* Pop the nesting stack element by element until we pop off
259 the element which is at the top of STACK.
260 Update all the other stacks, popping off elements from them
261 as we pop them from nesting_stack. */
263 #define POPSTACK(STACK) \
264 do { struct nesting *target = STACK; \
265 struct nesting *this; \
266 do { this = nesting_stack; \
267 if (loop_stack == this) \
268 loop_stack = loop_stack->next; \
269 if (cond_stack == this) \
270 cond_stack = cond_stack->next; \
271 if (block_stack == this) \
272 block_stack = block_stack->next; \
273 if (stack_block_stack == this) \
274 stack_block_stack = stack_block_stack->next; \
275 if (case_stack == this) \
276 case_stack = case_stack->next; \
277 nesting_depth = nesting_stack->depth - 1; \
278 nesting_stack = this->all; } \
279 while (this != target); } while (0)
281 /* In some cases it is impossible to generate code for a forward goto
282 until the label definition is seen. This happens when it may be necessary
283 for the goto to reset the stack pointer: we don't yet know how to do that.
284 So expand_goto puts an entry on this fixup list.
285 Each time a binding contour that resets the stack is exited,
287 If the target label has now been defined, we can insert the proper code. */
289 struct goto_fixup GTY(())
291 /* Points to following fixup. */
292 struct goto_fixup *next;
293 /* Points to the insn before the jump insn.
294 If more code must be inserted, it goes after this insn. */
296 /* The LABEL_DECL that this jump is jumping to, or 0
297 for break, continue or return. */
299 /* The BLOCK for the place where this goto was found. */
301 /* The CODE_LABEL rtx that this is jumping to. */
303 /* Number of binding contours started in current function
304 before the label reference. */
305 int block_start_count;
306 /* The outermost stack level that should be restored for this jump.
307 Each time a binding contour that resets the stack is exited,
308 if the target label is *not* yet defined, this slot is updated. */
310 /* List of lists of cleanup expressions to be run by this goto.
311 There is one element for each block that this goto is within.
312 The tail of this list can be 0,
313 if all remaining elements would be empty.
314 The TREE_VALUE contains the cleanup list of that block as of the
315 time this goto was seen.
316 The TREE_ADDRESSABLE flag is 1 for a block that has been exited. */
317 tree cleanup_list_list;
320 /* Within any binding contour that must restore a stack level,
321 all labels are recorded with a chain of these structures. */
323 struct label_chain GTY(())
325 /* Points to following fixup. */
326 struct label_chain *next;
330 struct stmt_status GTY(())
332 /* Chain of all pending binding contours. */
333 struct nesting * x_block_stack;
335 /* If any new stacks are added here, add them to POPSTACKS too. */
337 /* Chain of all pending binding contours that restore stack levels
339 struct nesting * x_stack_block_stack;
341 /* Chain of all pending conditional statements. */
342 struct nesting * x_cond_stack;
344 /* Chain of all pending loops. */
345 struct nesting * x_loop_stack;
347 /* Chain of all pending case or switch statements. */
348 struct nesting * x_case_stack;
350 /* Separate chain including all of the above,
351 chained through the `all' field. */
352 struct nesting * x_nesting_stack;
354 /* Number of entries on nesting_stack now. */
357 /* Number of binding contours started so far in this function. */
358 int x_block_start_count;
360 /* Each time we expand an expression-statement,
361 record the expr's type and its RTL value here. */
362 tree x_last_expr_type;
363 rtx x_last_expr_value;
365 /* Nonzero if within a ({...}) grouping, in which case we must
366 always compute a value for each expr-stmt in case it is the last one. */
367 int x_expr_stmts_for_value;
369 /* Location of last line-number note, whether we actually
370 emitted it or not. */
371 location_t x_emit_locus;
373 struct goto_fixup *x_goto_fixup_chain;
376 #define block_stack (cfun->stmt->x_block_stack)
377 #define stack_block_stack (cfun->stmt->x_stack_block_stack)
378 #define cond_stack (cfun->stmt->x_cond_stack)
379 #define loop_stack (cfun->stmt->x_loop_stack)
380 #define case_stack (cfun->stmt->x_case_stack)
381 #define nesting_stack (cfun->stmt->x_nesting_stack)
382 #define nesting_depth (cfun->stmt->x_nesting_depth)
383 #define current_block_start_count (cfun->stmt->x_block_start_count)
384 #define last_expr_type (cfun->stmt->x_last_expr_type)
385 #define last_expr_value (cfun->stmt->x_last_expr_value)
386 #define expr_stmts_for_value (cfun->stmt->x_expr_stmts_for_value)
387 #define emit_locus (cfun->stmt->x_emit_locus)
388 #define goto_fixup_chain (cfun->stmt->x_goto_fixup_chain)
390 /* Nonzero if we are using EH to handle cleanups. */
391 static int using_eh_for_cleanups_p = 0;
393 static int n_occurrences (int, const char *);
394 static bool decl_conflicts_with_clobbers_p (tree, const HARD_REG_SET);
395 static void expand_goto_internal (tree, rtx, rtx);
396 static int expand_fixup (tree, rtx, rtx);
397 static rtx expand_nl_handler_label (rtx, rtx);
398 static void expand_nl_goto_receiver (void);
399 static void expand_nl_goto_receivers (struct nesting *);
400 static void fixup_gotos (struct nesting *, rtx, tree, rtx, int);
401 static bool check_operand_nalternatives (tree, tree);
402 static bool check_unique_operand_names (tree, tree);
403 static char *resolve_operand_name_1 (char *, tree, tree);
404 static void expand_null_return_1 (rtx);
405 static enum br_predictor return_prediction (rtx);
406 static rtx shift_return_value (rtx);
407 static void expand_value_return (rtx);
408 static int tail_recursion_args (tree, tree);
409 static void expand_cleanups (tree, int, int);
410 static void check_seenlabel (void);
411 static void do_jump_if_equal (rtx, rtx, rtx, int);
412 static int estimate_case_costs (case_node_ptr);
413 static bool same_case_target_p (rtx, rtx);
414 static void strip_default_case_nodes (case_node_ptr *, rtx);
415 static bool lshift_cheap_p (void);
416 static int case_bit_test_cmp (const void *, const void *);
417 static void emit_case_bit_tests (tree, tree, tree, tree, case_node_ptr, rtx);
418 static void group_case_nodes (case_node_ptr);
419 static void balance_case_nodes (case_node_ptr *, case_node_ptr);
420 static int node_has_low_bound (case_node_ptr, tree);
421 static int node_has_high_bound (case_node_ptr, tree);
422 static int node_is_bounded (case_node_ptr, tree);
423 static void emit_jump_if_reachable (rtx);
424 static void emit_case_nodes (rtx, case_node_ptr, rtx, tree);
425 static struct case_node *case_tree2list (case_node *, case_node *);
428 using_eh_for_cleanups (void)
430 using_eh_for_cleanups_p = 1;
434 init_stmt_for_function (void)
436 cfun->stmt = ggc_alloc_cleared (sizeof (struct stmt_status));
439 /* Record the current file and line. Called from emit_line_note. */
442 set_file_and_line_for_stmt (location_t location)
444 /* If we're outputting an inline function, and we add a line note,
445 there may be no CFUN->STMT information. So, there's no need to
448 emit_locus = location;
451 /* Emit a no-op instruction. */
458 last_insn = get_last_insn ();
460 && (GET_CODE (last_insn) == CODE_LABEL
461 || (GET_CODE (last_insn) == NOTE
462 && prev_real_insn (last_insn) == 0)))
463 emit_insn (gen_nop ());
466 /* Return the rtx-label that corresponds to a LABEL_DECL,
467 creating it if necessary. */
470 label_rtx (tree label)
472 if (TREE_CODE (label) != LABEL_DECL)
475 if (!DECL_RTL_SET_P (label))
476 SET_DECL_RTL (label, gen_label_rtx ());
478 return DECL_RTL (label);
481 /* As above, but also put it on the forced-reference list of the
482 function that contains it. */
484 force_label_rtx (tree label)
486 rtx ref = label_rtx (label);
487 tree function = decl_function_context (label);
493 if (function != current_function_decl
494 && function != inline_function_decl)
495 p = find_function_data (function);
499 p->expr->x_forced_labels = gen_rtx_EXPR_LIST (VOIDmode, ref,
500 p->expr->x_forced_labels);
504 /* Add an unconditional jump to LABEL as the next sequential instruction. */
507 emit_jump (rtx label)
509 do_pending_stack_adjust ();
510 emit_jump_insn (gen_jump (label));
514 /* Emit code to jump to the address
515 specified by the pointer expression EXP. */
518 expand_computed_goto (tree exp)
520 rtx x = expand_expr (exp, NULL_RTX, VOIDmode, 0);
522 x = convert_memory_address (Pmode, x);
526 if (! cfun->computed_goto_common_label)
528 cfun->computed_goto_common_reg = copy_to_mode_reg (Pmode, x);
529 cfun->computed_goto_common_label = gen_label_rtx ();
530 emit_label (cfun->computed_goto_common_label);
532 do_pending_stack_adjust ();
533 emit_indirect_jump (cfun->computed_goto_common_reg);
535 current_function_has_computed_jump = 1;
539 emit_move_insn (cfun->computed_goto_common_reg, x);
540 emit_jump (cfun->computed_goto_common_label);
544 /* Handle goto statements and the labels that they can go to. */
546 /* Specify the location in the RTL code of a label LABEL,
547 which is a LABEL_DECL tree node.
549 This is used for the kind of label that the user can jump to with a
550 goto statement, and for alternatives of a switch or case statement.
551 RTL labels generated for loops and conditionals don't go through here;
552 they are generated directly at the RTL level, by other functions below.
554 Note that this has nothing to do with defining label *names*.
555 Languages vary in how they do that and what that even means. */
558 expand_label (tree label)
560 struct label_chain *p;
562 do_pending_stack_adjust ();
563 emit_label (label_rtx (label));
564 if (DECL_NAME (label))
565 LABEL_NAME (DECL_RTL (label)) = IDENTIFIER_POINTER (DECL_NAME (label));
567 if (stack_block_stack != 0)
569 p = ggc_alloc (sizeof (struct label_chain));
570 p->next = stack_block_stack->data.block.label_chain;
571 stack_block_stack->data.block.label_chain = p;
576 /* Declare that LABEL (a LABEL_DECL) may be used for nonlocal gotos
577 from nested functions. */
580 declare_nonlocal_label (tree label)
582 rtx slot = assign_stack_local (Pmode, GET_MODE_SIZE (Pmode), 0);
584 nonlocal_labels = tree_cons (NULL_TREE, label, nonlocal_labels);
585 LABEL_PRESERVE_P (label_rtx (label)) = 1;
586 if (nonlocal_goto_handler_slots == 0)
588 emit_stack_save (SAVE_NONLOCAL,
589 &nonlocal_goto_stack_level,
590 PREV_INSN (tail_recursion_reentry));
592 nonlocal_goto_handler_slots
593 = gen_rtx_EXPR_LIST (VOIDmode, slot, nonlocal_goto_handler_slots);
596 /* Generate RTL code for a `goto' statement with target label LABEL.
597 LABEL should be a LABEL_DECL tree node that was or will later be
598 defined with `expand_label'. */
601 expand_goto (tree label)
605 /* Check for a nonlocal goto to a containing function. */
606 context = decl_function_context (label);
607 if (context != 0 && context != current_function_decl)
609 struct function *p = find_function_data (context);
610 rtx label_ref = gen_rtx_LABEL_REF (Pmode, label_rtx (label));
611 rtx handler_slot, static_chain, save_area, insn;
614 /* Find the corresponding handler slot for this label. */
615 handler_slot = p->x_nonlocal_goto_handler_slots;
616 for (link = p->x_nonlocal_labels; TREE_VALUE (link) != label;
617 link = TREE_CHAIN (link))
618 handler_slot = XEXP (handler_slot, 1);
619 handler_slot = XEXP (handler_slot, 0);
621 p->has_nonlocal_label = 1;
622 current_function_has_nonlocal_goto = 1;
623 LABEL_REF_NONLOCAL_P (label_ref) = 1;
625 /* Copy the rtl for the slots so that they won't be shared in
626 case the virtual stack vars register gets instantiated differently
627 in the parent than in the child. */
629 static_chain = copy_to_reg (lookup_static_chain (label));
631 /* Get addr of containing function's current nonlocal goto handler,
632 which will do any cleanups and then jump to the label. */
633 handler_slot = copy_to_reg (replace_rtx (copy_rtx (handler_slot),
634 virtual_stack_vars_rtx,
637 /* Get addr of containing function's nonlocal save area. */
638 save_area = p->x_nonlocal_goto_stack_level;
640 save_area = replace_rtx (copy_rtx (save_area),
641 virtual_stack_vars_rtx, static_chain);
643 #if HAVE_nonlocal_goto
644 if (HAVE_nonlocal_goto)
645 emit_insn (gen_nonlocal_goto (static_chain, handler_slot,
646 save_area, label_ref));
650 emit_insn (gen_rtx_CLOBBER (VOIDmode,
651 gen_rtx_MEM (BLKmode,
652 gen_rtx_SCRATCH (VOIDmode))));
653 emit_insn (gen_rtx_CLOBBER (VOIDmode,
654 gen_rtx_MEM (BLKmode,
655 hard_frame_pointer_rtx)));
657 /* Restore frame pointer for containing function.
658 This sets the actual hard register used for the frame pointer
659 to the location of the function's incoming static chain info.
660 The non-local goto handler will then adjust it to contain the
661 proper value and reload the argument pointer, if needed. */
662 emit_move_insn (hard_frame_pointer_rtx, static_chain);
663 emit_stack_restore (SAVE_NONLOCAL, save_area, NULL_RTX);
665 /* USE of hard_frame_pointer_rtx added for consistency;
666 not clear if really needed. */
667 emit_insn (gen_rtx_USE (VOIDmode, hard_frame_pointer_rtx));
668 emit_insn (gen_rtx_USE (VOIDmode, stack_pointer_rtx));
669 emit_indirect_jump (handler_slot);
672 /* Search backwards to the jump insn and mark it as a
674 for (insn = get_last_insn (); insn; insn = PREV_INSN (insn))
676 if (GET_CODE (insn) == JUMP_INSN)
678 REG_NOTES (insn) = alloc_EXPR_LIST (REG_NON_LOCAL_GOTO,
679 const0_rtx, REG_NOTES (insn));
682 else if (GET_CODE (insn) == CALL_INSN)
687 expand_goto_internal (label, label_rtx (label), NULL_RTX);
690 /* Generate RTL code for a `goto' statement with target label BODY.
691 LABEL should be a LABEL_REF.
692 LAST_INSN, if non-0, is the rtx we should consider as the last
693 insn emitted (for the purposes of cleaning up a return). */
696 expand_goto_internal (tree body, rtx label, rtx last_insn)
698 struct nesting *block;
701 if (GET_CODE (label) != CODE_LABEL)
704 /* If label has already been defined, we can tell now
705 whether and how we must alter the stack level. */
707 if (PREV_INSN (label) != 0)
709 /* Find the innermost pending block that contains the label.
710 (Check containment by comparing insn-uids.)
711 Then restore the outermost stack level within that block,
712 and do cleanups of all blocks contained in it. */
713 for (block = block_stack; block; block = block->next)
715 if (INSN_UID (block->data.block.first_insn) < INSN_UID (label))
717 if (block->data.block.stack_level != 0)
718 stack_level = block->data.block.stack_level;
719 /* Execute the cleanups for blocks we are exiting. */
720 if (block->data.block.cleanups != 0)
722 expand_cleanups (block->data.block.cleanups, 1, 1);
723 do_pending_stack_adjust ();
729 /* Ensure stack adjust isn't done by emit_jump, as this
730 would clobber the stack pointer. This one should be
731 deleted as dead by flow. */
732 clear_pending_stack_adjust ();
733 do_pending_stack_adjust ();
735 /* Don't do this adjust if it's to the end label and this function
736 is to return with a depressed stack pointer. */
737 if (label == return_label
738 && (((TREE_CODE (TREE_TYPE (current_function_decl))
740 && (TYPE_RETURNS_STACK_DEPRESSED
741 (TREE_TYPE (current_function_decl))))))
744 emit_stack_restore (SAVE_BLOCK, stack_level, NULL_RTX);
747 if (body != 0 && DECL_TOO_LATE (body))
748 error ("jump to `%s' invalidly jumps into binding contour",
749 IDENTIFIER_POINTER (DECL_NAME (body)));
751 /* Label not yet defined: may need to put this goto
752 on the fixup list. */
753 else if (! expand_fixup (body, label, last_insn))
755 /* No fixup needed. Record that the label is the target
756 of at least one goto that has no fixup. */
758 TREE_ADDRESSABLE (body) = 1;
764 /* Generate if necessary a fixup for a goto
765 whose target label in tree structure (if any) is TREE_LABEL
766 and whose target in rtl is RTL_LABEL.
768 If LAST_INSN is nonzero, we pretend that the jump appears
769 after insn LAST_INSN instead of at the current point in the insn stream.
771 The fixup will be used later to insert insns just before the goto.
772 Those insns will restore the stack level as appropriate for the
773 target label, and will (in the case of C++) also invoke any object
774 destructors which have to be invoked when we exit the scopes which
775 are exited by the goto.
777 Value is nonzero if a fixup is made. */
780 expand_fixup (tree tree_label, rtx rtl_label, rtx last_insn)
782 struct nesting *block, *end_block;
784 /* See if we can recognize which block the label will be output in.
785 This is possible in some very common cases.
786 If we succeed, set END_BLOCK to that block.
787 Otherwise, set it to 0. */
790 && (rtl_label == cond_stack->data.cond.endif_label
791 || rtl_label == cond_stack->data.cond.next_label))
792 end_block = cond_stack;
793 /* If we are in a loop, recognize certain labels which
794 are likely targets. This reduces the number of fixups
795 we need to create. */
797 && (rtl_label == loop_stack->data.loop.start_label
798 || rtl_label == loop_stack->data.loop.end_label
799 || rtl_label == loop_stack->data.loop.continue_label))
800 end_block = loop_stack;
804 /* Now set END_BLOCK to the binding level to which we will return. */
808 struct nesting *next_block = end_block->all;
811 /* First see if the END_BLOCK is inside the innermost binding level.
812 If so, then no cleanups or stack levels are relevant. */
813 while (next_block && next_block != block)
814 next_block = next_block->all;
819 /* Otherwise, set END_BLOCK to the innermost binding level
820 which is outside the relevant control-structure nesting. */
821 next_block = block_stack->next;
822 for (block = block_stack; block != end_block; block = block->all)
823 if (block == next_block)
824 next_block = next_block->next;
825 end_block = next_block;
828 /* Does any containing block have a stack level or cleanups?
829 If not, no fixup is needed, and that is the normal case
830 (the only case, for standard C). */
831 for (block = block_stack; block != end_block; block = block->next)
832 if (block->data.block.stack_level != 0
833 || block->data.block.cleanups != 0)
836 if (block != end_block)
838 /* Ok, a fixup is needed. Add a fixup to the list of such. */
839 struct goto_fixup *fixup = ggc_alloc (sizeof (struct goto_fixup));
840 /* In case an old stack level is restored, make sure that comes
841 after any pending stack adjust. */
842 /* ?? If the fixup isn't to come at the present position,
843 doing the stack adjust here isn't useful. Doing it with our
844 settings at that location isn't useful either. Let's hope
847 do_pending_stack_adjust ();
848 fixup->target = tree_label;
849 fixup->target_rtl = rtl_label;
851 /* Create a BLOCK node and a corresponding matched set of
852 NOTE_INSN_BLOCK_BEG and NOTE_INSN_BLOCK_END notes at
853 this point. The notes will encapsulate any and all fixup
854 code which we might later insert at this point in the insn
855 stream. Also, the BLOCK node will be the parent (i.e. the
856 `SUPERBLOCK') of any other BLOCK nodes which we might create
857 later on when we are expanding the fixup code.
859 Note that optimization passes (including expand_end_loop)
860 might move the *_BLOCK notes away, so we use a NOTE_INSN_DELETED
864 rtx original_before_jump
865 = last_insn ? last_insn : get_last_insn ();
870 block = make_node (BLOCK);
871 TREE_USED (block) = 1;
873 if (!cfun->x_whole_function_mode_p)
874 (*lang_hooks.decls.insert_block) (block);
878 = BLOCK_CHAIN (DECL_INITIAL (current_function_decl));
879 BLOCK_CHAIN (DECL_INITIAL (current_function_decl))
884 start = emit_note (NOTE_INSN_BLOCK_BEG);
885 if (cfun->x_whole_function_mode_p)
886 NOTE_BLOCK (start) = block;
887 fixup->before_jump = emit_note (NOTE_INSN_DELETED);
888 end = emit_note (NOTE_INSN_BLOCK_END);
889 if (cfun->x_whole_function_mode_p)
890 NOTE_BLOCK (end) = block;
891 fixup->context = block;
893 emit_insn_after (start, original_before_jump);
896 fixup->block_start_count = current_block_start_count;
897 fixup->stack_level = 0;
898 fixup->cleanup_list_list
899 = ((block->data.block.outer_cleanups
900 || block->data.block.cleanups)
901 ? tree_cons (NULL_TREE, block->data.block.cleanups,
902 block->data.block.outer_cleanups)
904 fixup->next = goto_fixup_chain;
905 goto_fixup_chain = fixup;
911 /* Expand any needed fixups in the outputmost binding level of the
912 function. FIRST_INSN is the first insn in the function. */
915 expand_fixups (rtx first_insn)
917 fixup_gotos (NULL, NULL_RTX, NULL_TREE, first_insn, 0);
920 /* When exiting a binding contour, process all pending gotos requiring fixups.
921 THISBLOCK is the structure that describes the block being exited.
922 STACK_LEVEL is the rtx for the stack level to restore exiting this contour.
923 CLEANUP_LIST is a list of expressions to evaluate on exiting this contour.
924 FIRST_INSN is the insn that began this contour.
926 Gotos that jump out of this contour must restore the
927 stack level and do the cleanups before actually jumping.
929 DONT_JUMP_IN positive means report error if there is a jump into this
930 contour from before the beginning of the contour. This is also done if
931 STACK_LEVEL is nonzero unless DONT_JUMP_IN is negative. */
934 fixup_gotos (struct nesting *thisblock, rtx stack_level,
935 tree cleanup_list, rtx first_insn, int dont_jump_in)
937 struct goto_fixup *f, *prev;
939 /* F is the fixup we are considering; PREV is the previous one. */
940 /* We run this loop in two passes so that cleanups of exited blocks
941 are run first, and blocks that are exited are marked so
944 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
946 /* Test for a fixup that is inactive because it is already handled. */
947 if (f->before_jump == 0)
949 /* Delete inactive fixup from the chain, if that is easy to do. */
951 prev->next = f->next;
953 /* Has this fixup's target label been defined?
954 If so, we can finalize it. */
955 else if (PREV_INSN (f->target_rtl) != 0)
959 /* If this fixup jumped into this contour from before the beginning
960 of this contour, report an error. This code used to use
961 the first non-label insn after f->target_rtl, but that's
962 wrong since such can be added, by things like put_var_into_stack
963 and have INSN_UIDs that are out of the range of the block. */
964 /* ??? Bug: this does not detect jumping in through intermediate
965 blocks that have stack levels or cleanups.
966 It detects only a problem with the innermost block
969 && (dont_jump_in > 0 || (dont_jump_in == 0 && stack_level)
971 && INSN_UID (first_insn) < INSN_UID (f->target_rtl)
972 && INSN_UID (first_insn) > INSN_UID (f->before_jump)
973 && ! DECL_ERROR_ISSUED (f->target))
975 error ("%Jlabel '%D' used before containing binding contour",
976 f->target, f->target);
977 /* Prevent multiple errors for one label. */
978 DECL_ERROR_ISSUED (f->target) = 1;
981 /* We will expand the cleanups into a sequence of their own and
982 then later on we will attach this new sequence to the insn
983 stream just ahead of the actual jump insn. */
987 /* Temporarily restore the lexical context where we will
988 logically be inserting the fixup code. We do this for the
989 sake of getting the debugging information right. */
991 (*lang_hooks.decls.pushlevel) (0);
992 (*lang_hooks.decls.set_block) (f->context);
994 /* Expand the cleanups for blocks this jump exits. */
995 if (f->cleanup_list_list)
998 for (lists = f->cleanup_list_list; lists; lists = TREE_CHAIN (lists))
999 /* Marked elements correspond to blocks that have been closed.
1000 Do their cleanups. */
1001 if (TREE_ADDRESSABLE (lists)
1002 && TREE_VALUE (lists) != 0)
1004 expand_cleanups (TREE_VALUE (lists), 1, 1);
1005 /* Pop any pushes done in the cleanups,
1006 in case function is about to return. */
1007 do_pending_stack_adjust ();
1011 /* Restore stack level for the biggest contour that this
1012 jump jumps out of. */
1014 && ! (f->target_rtl == return_label
1015 && ((TREE_CODE (TREE_TYPE (current_function_decl))
1017 && (TYPE_RETURNS_STACK_DEPRESSED
1018 (TREE_TYPE (current_function_decl))))))
1019 emit_stack_restore (SAVE_BLOCK, f->stack_level, f->before_jump);
1021 /* Finish up the sequence containing the insns which implement the
1022 necessary cleanups, and then attach that whole sequence to the
1023 insn stream just ahead of the actual jump insn. Attaching it
1024 at that point insures that any cleanups which are in fact
1025 implicit C++ object destructions (which must be executed upon
1026 leaving the block) appear (to the debugger) to be taking place
1027 in an area of the generated code where the object(s) being
1028 destructed are still "in scope". */
1030 cleanup_insns = get_insns ();
1031 (*lang_hooks.decls.poplevel) (1, 0, 0);
1034 emit_insn_after (cleanup_insns, f->before_jump);
1040 /* For any still-undefined labels, do the cleanups for this block now.
1041 We must do this now since items in the cleanup list may go out
1042 of scope when the block ends. */
1043 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
1044 if (f->before_jump != 0
1045 && PREV_INSN (f->target_rtl) == 0
1046 /* Label has still not appeared. If we are exiting a block with
1047 a stack level to restore, that started before the fixup,
1048 mark this stack level as needing restoration
1049 when the fixup is later finalized. */
1051 /* Note: if THISBLOCK == 0 and we have a label that hasn't appeared, it
1052 means the label is undefined. That's erroneous, but possible. */
1053 && (thisblock->data.block.block_start_count
1054 <= f->block_start_count))
1056 tree lists = f->cleanup_list_list;
1059 for (; lists; lists = TREE_CHAIN (lists))
1060 /* If the following elt. corresponds to our containing block
1061 then the elt. must be for this block. */
1062 if (TREE_CHAIN (lists) == thisblock->data.block.outer_cleanups)
1065 (*lang_hooks.decls.pushlevel) (0);
1066 (*lang_hooks.decls.set_block) (f->context);
1067 expand_cleanups (TREE_VALUE (lists), 1, 1);
1068 do_pending_stack_adjust ();
1069 cleanup_insns = get_insns ();
1070 (*lang_hooks.decls.poplevel) (1, 0, 0);
1072 if (cleanup_insns != 0)
1074 = emit_insn_after (cleanup_insns, f->before_jump);
1076 f->cleanup_list_list = TREE_CHAIN (lists);
1080 f->stack_level = stack_level;
1084 /* Return the number of times character C occurs in string S. */
1086 n_occurrences (int c, const char *s)
1094 /* Generate RTL for an asm statement (explicit assembler code).
1095 STRING is a STRING_CST node containing the assembler code text,
1096 or an ADDR_EXPR containing a STRING_CST. VOL nonzero means the
1097 insn is volatile; don't optimize it. */
1100 expand_asm (tree string, int vol)
1104 if (TREE_CODE (string) == ADDR_EXPR)
1105 string = TREE_OPERAND (string, 0);
1107 body = gen_rtx_ASM_INPUT (VOIDmode, TREE_STRING_POINTER (string));
1109 MEM_VOLATILE_P (body) = vol;
1116 /* Parse the output constraint pointed to by *CONSTRAINT_P. It is the
1117 OPERAND_NUMth output operand, indexed from zero. There are NINPUTS
1118 inputs and NOUTPUTS outputs to this extended-asm. Upon return,
1119 *ALLOWS_MEM will be TRUE iff the constraint allows the use of a
1120 memory operand. Similarly, *ALLOWS_REG will be TRUE iff the
1121 constraint allows the use of a register operand. And, *IS_INOUT
1122 will be true if the operand is read-write, i.e., if it is used as
1123 an input as well as an output. If *CONSTRAINT_P is not in
1124 canonical form, it will be made canonical. (Note that `+' will be
1125 replaced with `=' as part of this process.)
1127 Returns TRUE if all went well; FALSE if an error occurred. */
1130 parse_output_constraint (const char **constraint_p, int operand_num,
1131 int ninputs, int noutputs, bool *allows_mem,
1132 bool *allows_reg, bool *is_inout)
1134 const char *constraint = *constraint_p;
1137 /* Assume the constraint doesn't allow the use of either a register
1139 *allows_mem = false;
1140 *allows_reg = false;
1142 /* Allow the `=' or `+' to not be at the beginning of the string,
1143 since it wasn't explicitly documented that way, and there is a
1144 large body of code that puts it last. Swap the character to
1145 the front, so as not to uglify any place else. */
1146 p = strchr (constraint, '=');
1148 p = strchr (constraint, '+');
1150 /* If the string doesn't contain an `=', issue an error
1154 error ("output operand constraint lacks `='");
1158 /* If the constraint begins with `+', then the operand is both read
1159 from and written to. */
1160 *is_inout = (*p == '+');
1162 /* Canonicalize the output constraint so that it begins with `='. */
1163 if (p != constraint || is_inout)
1166 size_t c_len = strlen (constraint);
1168 if (p != constraint)
1169 warning ("output constraint `%c' for operand %d is not at the beginning",
1172 /* Make a copy of the constraint. */
1173 buf = alloca (c_len + 1);
1174 strcpy (buf, constraint);
1175 /* Swap the first character and the `=' or `+'. */
1176 buf[p - constraint] = buf[0];
1177 /* Make sure the first character is an `='. (Until we do this,
1178 it might be a `+'.) */
1180 /* Replace the constraint with the canonicalized string. */
1181 *constraint_p = ggc_alloc_string (buf, c_len);
1182 constraint = *constraint_p;
1185 /* Loop through the constraint string. */
1186 for (p = constraint + 1; *p; p += CONSTRAINT_LEN (*p, p))
1191 error ("operand constraint contains incorrectly positioned '+' or '='");
1195 if (operand_num + 1 == ninputs + noutputs)
1197 error ("`%%' constraint used with last operand");
1202 case 'V': case 'm': case 'o':
1206 case '?': case '!': case '*': case '&': case '#':
1207 case 'E': case 'F': case 'G': case 'H':
1208 case 's': case 'i': case 'n':
1209 case 'I': case 'J': case 'K': case 'L': case 'M':
1210 case 'N': case 'O': case 'P': case ',':
1213 case '0': case '1': case '2': case '3': case '4':
1214 case '5': case '6': case '7': case '8': case '9':
1216 error ("matching constraint not valid in output operand");
1220 /* ??? Before flow, auto inc/dec insns are not supposed to exist,
1221 excepting those that expand_call created. So match memory
1238 if (REG_CLASS_FROM_CONSTRAINT (*p, p) != NO_REGS)
1240 #ifdef EXTRA_CONSTRAINT_STR
1241 else if (EXTRA_ADDRESS_CONSTRAINT (*p, p))
1243 else if (EXTRA_MEMORY_CONSTRAINT (*p, p))
1247 /* Otherwise we can't assume anything about the nature of
1248 the constraint except that it isn't purely registers.
1249 Treat it like "g" and hope for the best. */
1260 /* Similar, but for input constraints. */
1263 parse_input_constraint (const char **constraint_p, int input_num,
1264 int ninputs, int noutputs, int ninout,
1265 const char * const * constraints,
1266 bool *allows_mem, bool *allows_reg)
1268 const char *constraint = *constraint_p;
1269 const char *orig_constraint = constraint;
1270 size_t c_len = strlen (constraint);
1273 /* Assume the constraint doesn't allow the use of either
1274 a register or memory. */
1275 *allows_mem = false;
1276 *allows_reg = false;
1278 /* Make sure constraint has neither `=', `+', nor '&'. */
1280 for (j = 0; j < c_len; j += CONSTRAINT_LEN (constraint[j], constraint+j))
1281 switch (constraint[j])
1283 case '+': case '=': case '&':
1284 if (constraint == orig_constraint)
1286 error ("input operand constraint contains `%c'", constraint[j]);
1292 if (constraint == orig_constraint
1293 && input_num + 1 == ninputs - ninout)
1295 error ("`%%' constraint used with last operand");
1300 case 'V': case 'm': case 'o':
1305 case '?': case '!': case '*': case '#':
1306 case 'E': case 'F': case 'G': case 'H':
1307 case 's': case 'i': case 'n':
1308 case 'I': case 'J': case 'K': case 'L': case 'M':
1309 case 'N': case 'O': case 'P': case ',':
1312 /* Whether or not a numeric constraint allows a register is
1313 decided by the matching constraint, and so there is no need
1314 to do anything special with them. We must handle them in
1315 the default case, so that we don't unnecessarily force
1316 operands to memory. */
1317 case '0': case '1': case '2': case '3': case '4':
1318 case '5': case '6': case '7': case '8': case '9':
1321 unsigned long match;
1323 match = strtoul (constraint + j, &end, 10);
1324 if (match >= (unsigned long) noutputs)
1326 error ("matching constraint references invalid operand number");
1330 /* Try and find the real constraint for this dup. Only do this
1331 if the matching constraint is the only alternative. */
1333 && (j == 0 || (j == 1 && constraint[0] == '%')))
1335 constraint = constraints[match];
1336 *constraint_p = constraint;
1337 c_len = strlen (constraint);
1339 /* ??? At the end of the loop, we will skip the first part of
1340 the matched constraint. This assumes not only that the
1341 other constraint is an output constraint, but also that
1342 the '=' or '+' come first. */
1346 j = end - constraint;
1347 /* Anticipate increment at end of loop. */
1362 if (! ISALPHA (constraint[j]))
1364 error ("invalid punctuation `%c' in constraint", constraint[j]);
1367 if (REG_CLASS_FROM_CONSTRAINT (constraint[j], constraint + j)
1370 #ifdef EXTRA_CONSTRAINT_STR
1371 else if (EXTRA_ADDRESS_CONSTRAINT (constraint[j], constraint + j))
1373 else if (EXTRA_MEMORY_CONSTRAINT (constraint[j], constraint + j))
1377 /* Otherwise we can't assume anything about the nature of
1378 the constraint except that it isn't purely registers.
1379 Treat it like "g" and hope for the best. */
1390 /* Check for overlap between registers marked in CLOBBERED_REGS and
1391 anything inappropriate in DECL. Emit error and return TRUE for error,
1395 decl_conflicts_with_clobbers_p (tree decl, const HARD_REG_SET clobbered_regs)
1397 /* Conflicts between asm-declared register variables and the clobber
1398 list are not allowed. */
1399 if ((TREE_CODE (decl) == VAR_DECL || TREE_CODE (decl) == PARM_DECL)
1400 && DECL_REGISTER (decl)
1401 && REG_P (DECL_RTL (decl))
1402 && REGNO (DECL_RTL (decl)) < FIRST_PSEUDO_REGISTER)
1404 rtx reg = DECL_RTL (decl);
1407 for (regno = REGNO (reg);
1408 regno < (REGNO (reg)
1409 + HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg)));
1411 if (TEST_HARD_REG_BIT (clobbered_regs, regno))
1413 error ("asm-specifier for variable `%s' conflicts with asm clobber list",
1414 IDENTIFIER_POINTER (DECL_NAME (decl)));
1416 /* Reset registerness to stop multiple errors emitted for a
1418 DECL_REGISTER (decl) = 0;
1425 /* Generate RTL for an asm statement with arguments.
1426 STRING is the instruction template.
1427 OUTPUTS is a list of output arguments (lvalues); INPUTS a list of inputs.
1428 Each output or input has an expression in the TREE_VALUE and
1429 and a tree list in TREE_PURPOSE which in turn contains a constraint
1430 name in TREE_VALUE (or NULL_TREE) and a constraint string
1432 CLOBBERS is a list of STRING_CST nodes each naming a hard register
1433 that is clobbered by this insn.
1435 Not all kinds of lvalue that may appear in OUTPUTS can be stored directly.
1436 Some elements of OUTPUTS may be replaced with trees representing temporary
1437 values. The caller should copy those temporary values to the originally
1440 VOL nonzero means the insn is volatile; don't optimize it. */
1443 expand_asm_operands (tree string, tree outputs, tree inputs,
1444 tree clobbers, int vol, location_t locus)
1446 rtvec argvec, constraintvec;
1448 int ninputs = list_length (inputs);
1449 int noutputs = list_length (outputs);
1452 HARD_REG_SET clobbered_regs;
1453 int clobber_conflict_found = 0;
1457 /* Vector of RTX's of evaluated output operands. */
1458 rtx *output_rtx = alloca (noutputs * sizeof (rtx));
1459 int *inout_opnum = alloca (noutputs * sizeof (int));
1460 rtx *real_output_rtx = alloca (noutputs * sizeof (rtx));
1461 enum machine_mode *inout_mode
1462 = alloca (noutputs * sizeof (enum machine_mode));
1463 const char **constraints
1464 = alloca ((noutputs + ninputs) * sizeof (const char *));
1465 int old_generating_concat_p = generating_concat_p;
1467 /* An ASM with no outputs needs to be treated as volatile, for now. */
1471 if (! check_operand_nalternatives (outputs, inputs))
1474 string = resolve_asm_operand_names (string, outputs, inputs);
1476 /* Collect constraints. */
1478 for (t = outputs; t ; t = TREE_CHAIN (t), i++)
1479 constraints[i] = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
1480 for (t = inputs; t ; t = TREE_CHAIN (t), i++)
1481 constraints[i] = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
1483 #ifdef MD_ASM_CLOBBERS
1484 /* Sometimes we wish to automatically clobber registers across an asm.
1485 Case in point is when the i386 backend moved from cc0 to a hard reg --
1486 maintaining source-level compatibility means automatically clobbering
1487 the flags register. */
1488 MD_ASM_CLOBBERS (clobbers);
1491 /* Count the number of meaningful clobbered registers, ignoring what
1492 we would ignore later. */
1494 CLEAR_HARD_REG_SET (clobbered_regs);
1495 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1497 const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1499 i = decode_reg_name (regname);
1500 if (i >= 0 || i == -4)
1503 error ("unknown register name `%s' in `asm'", regname);
1505 /* Mark clobbered registers. */
1508 /* Clobbering the PIC register is an error */
1509 if (i == (int) PIC_OFFSET_TABLE_REGNUM)
1511 error ("PIC register `%s' clobbered in `asm'", regname);
1515 SET_HARD_REG_BIT (clobbered_regs, i);
1521 /* First pass over inputs and outputs checks validity and sets
1522 mark_addressable if needed. */
1525 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1527 tree val = TREE_VALUE (tail);
1528 tree type = TREE_TYPE (val);
1529 const char *constraint;
1534 /* If there's an erroneous arg, emit no insn. */
1535 if (type == error_mark_node)
1538 /* Try to parse the output constraint. If that fails, there's
1539 no point in going further. */
1540 constraint = constraints[i];
1541 if (!parse_output_constraint (&constraint, i, ninputs, noutputs,
1542 &allows_mem, &allows_reg, &is_inout))
1549 && GET_CODE (DECL_RTL (val)) == REG
1550 && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type))))
1551 (*lang_hooks.mark_addressable) (val);
1558 if (ninputs + noutputs > MAX_RECOG_OPERANDS)
1560 error ("more than %d operands in `asm'", MAX_RECOG_OPERANDS);
1564 for (i = 0, tail = inputs; tail; i++, tail = TREE_CHAIN (tail))
1566 bool allows_reg, allows_mem;
1567 const char *constraint;
1569 /* If there's an erroneous arg, emit no insn, because the ASM_INPUT
1570 would get VOIDmode and that could cause a crash in reload. */
1571 if (TREE_TYPE (TREE_VALUE (tail)) == error_mark_node)
1574 constraint = constraints[i + noutputs];
1575 if (! parse_input_constraint (&constraint, i, ninputs, noutputs, ninout,
1576 constraints, &allows_mem, &allows_reg))
1579 if (! allows_reg && allows_mem)
1580 (*lang_hooks.mark_addressable) (TREE_VALUE (tail));
1583 /* Second pass evaluates arguments. */
1586 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1588 tree val = TREE_VALUE (tail);
1589 tree type = TREE_TYPE (val);
1595 if (!parse_output_constraint (&constraints[i], i, ninputs,
1596 noutputs, &allows_mem, &allows_reg,
1600 /* If an output operand is not a decl or indirect ref and our constraint
1601 allows a register, make a temporary to act as an intermediate.
1602 Make the asm insn write into that, then our caller will copy it to
1603 the real output operand. Likewise for promoted variables. */
1605 generating_concat_p = 0;
1607 real_output_rtx[i] = NULL_RTX;
1608 if ((TREE_CODE (val) == INDIRECT_REF
1611 && (allows_mem || GET_CODE (DECL_RTL (val)) == REG)
1612 && ! (GET_CODE (DECL_RTL (val)) == REG
1613 && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type)))
1617 op = expand_expr (val, NULL_RTX, VOIDmode, EXPAND_WRITE);
1618 if (GET_CODE (op) == MEM)
1619 op = validize_mem (op);
1621 if (! allows_reg && GET_CODE (op) != MEM)
1622 error ("output number %d not directly addressable", i);
1623 if ((! allows_mem && GET_CODE (op) == MEM)
1624 || GET_CODE (op) == CONCAT)
1626 real_output_rtx[i] = protect_from_queue (op, 1);
1627 op = gen_reg_rtx (GET_MODE (op));
1629 emit_move_insn (op, real_output_rtx[i]);
1634 op = assign_temp (type, 0, 0, 1);
1635 op = validize_mem (op);
1636 TREE_VALUE (tail) = make_tree (type, op);
1640 generating_concat_p = old_generating_concat_p;
1644 inout_mode[ninout] = TYPE_MODE (type);
1645 inout_opnum[ninout++] = i;
1648 if (decl_conflicts_with_clobbers_p (val, clobbered_regs))
1649 clobber_conflict_found = 1;
1652 /* Make vectors for the expression-rtx, constraint strings,
1653 and named operands. */
1655 argvec = rtvec_alloc (ninputs);
1656 constraintvec = rtvec_alloc (ninputs);
1658 body = gen_rtx_ASM_OPERANDS ((noutputs == 0 ? VOIDmode
1659 : GET_MODE (output_rtx[0])),
1660 TREE_STRING_POINTER (string),
1661 empty_string, 0, argvec, constraintvec,
1662 locus.file, locus.line);
1664 MEM_VOLATILE_P (body) = vol;
1666 /* Eval the inputs and put them into ARGVEC.
1667 Put their constraints into ASM_INPUTs and store in CONSTRAINTS. */
1669 for (i = 0, tail = inputs; tail; tail = TREE_CHAIN (tail), ++i)
1671 bool allows_reg, allows_mem;
1672 const char *constraint;
1676 constraint = constraints[i + noutputs];
1677 if (! parse_input_constraint (&constraint, i, ninputs, noutputs, ninout,
1678 constraints, &allows_mem, &allows_reg))
1681 generating_concat_p = 0;
1683 val = TREE_VALUE (tail);
1684 type = TREE_TYPE (val);
1685 op = expand_expr (val, NULL_RTX, VOIDmode,
1686 (allows_mem && !allows_reg
1687 ? EXPAND_MEMORY : EXPAND_NORMAL));
1689 /* Never pass a CONCAT to an ASM. */
1690 if (GET_CODE (op) == CONCAT)
1691 op = force_reg (GET_MODE (op), op);
1692 else if (GET_CODE (op) == MEM)
1693 op = validize_mem (op);
1695 if (asm_operand_ok (op, constraint) <= 0)
1698 op = force_reg (TYPE_MODE (type), op);
1699 else if (!allows_mem)
1700 warning ("asm operand %d probably doesn't match constraints",
1702 else if (GET_CODE (op) == MEM)
1704 /* We won't recognize either volatile memory or memory
1705 with a queued address as available a memory_operand
1706 at this point. Ignore it: clearly this *is* a memory. */
1710 warning ("use of memory input without lvalue in "
1711 "asm operand %d is deprecated", i + noutputs);
1713 if (CONSTANT_P (op))
1715 rtx mem = force_const_mem (TYPE_MODE (type), op);
1717 op = validize_mem (mem);
1719 op = force_reg (TYPE_MODE (type), op);
1721 if (GET_CODE (op) == REG
1722 || GET_CODE (op) == SUBREG
1723 || GET_CODE (op) == ADDRESSOF
1724 || GET_CODE (op) == CONCAT)
1726 tree qual_type = build_qualified_type (type,
1728 | TYPE_QUAL_CONST));
1729 rtx memloc = assign_temp (qual_type, 1, 1, 1);
1730 memloc = validize_mem (memloc);
1731 emit_move_insn (memloc, op);
1737 generating_concat_p = old_generating_concat_p;
1738 ASM_OPERANDS_INPUT (body, i) = op;
1740 ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, i)
1741 = gen_rtx_ASM_INPUT (TYPE_MODE (type), constraints[i + noutputs]);
1743 if (decl_conflicts_with_clobbers_p (val, clobbered_regs))
1744 clobber_conflict_found = 1;
1747 /* Protect all the operands from the queue now that they have all been
1750 generating_concat_p = 0;
1752 for (i = 0; i < ninputs - ninout; i++)
1753 ASM_OPERANDS_INPUT (body, i)
1754 = protect_from_queue (ASM_OPERANDS_INPUT (body, i), 0);
1756 for (i = 0; i < noutputs; i++)
1757 output_rtx[i] = protect_from_queue (output_rtx[i], 1);
1759 /* For in-out operands, copy output rtx to input rtx. */
1760 for (i = 0; i < ninout; i++)
1762 int j = inout_opnum[i];
1765 ASM_OPERANDS_INPUT (body, ninputs - ninout + i)
1768 sprintf (buffer, "%d", j);
1769 ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, ninputs - ninout + i)
1770 = gen_rtx_ASM_INPUT (inout_mode[i], ggc_strdup (buffer));
1773 generating_concat_p = old_generating_concat_p;
1775 /* Now, for each output, construct an rtx
1776 (set OUTPUT (asm_operands INSN OUTPUTCONSTRAINT OUTPUTNUMBER
1777 ARGVEC CONSTRAINTS OPNAMES))
1778 If there is more than one, put them inside a PARALLEL. */
1780 if (noutputs == 1 && nclobbers == 0)
1782 ASM_OPERANDS_OUTPUT_CONSTRAINT (body) = constraints[0];
1783 emit_insn (gen_rtx_SET (VOIDmode, output_rtx[0], body));
1786 else if (noutputs == 0 && nclobbers == 0)
1788 /* No output operands: put in a raw ASM_OPERANDS rtx. */
1800 body = gen_rtx_PARALLEL (VOIDmode, rtvec_alloc (num + nclobbers));
1802 /* For each output operand, store a SET. */
1803 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1805 XVECEXP (body, 0, i)
1806 = gen_rtx_SET (VOIDmode,
1808 gen_rtx_ASM_OPERANDS
1809 (GET_MODE (output_rtx[i]),
1810 TREE_STRING_POINTER (string),
1811 constraints[i], i, argvec, constraintvec,
1812 locus.file, locus.line));
1814 MEM_VOLATILE_P (SET_SRC (XVECEXP (body, 0, i))) = vol;
1817 /* If there are no outputs (but there are some clobbers)
1818 store the bare ASM_OPERANDS into the PARALLEL. */
1821 XVECEXP (body, 0, i++) = obody;
1823 /* Store (clobber REG) for each clobbered register specified. */
1825 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1827 const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1828 int j = decode_reg_name (regname);
1833 if (j == -3) /* `cc', which is not a register */
1836 if (j == -4) /* `memory', don't cache memory across asm */
1838 XVECEXP (body, 0, i++)
1839 = gen_rtx_CLOBBER (VOIDmode,
1842 gen_rtx_SCRATCH (VOIDmode)));
1846 /* Ignore unknown register, error already signaled. */
1850 /* Use QImode since that's guaranteed to clobber just one reg. */
1851 clobbered_reg = gen_rtx_REG (QImode, j);
1853 /* Do sanity check for overlap between clobbers and respectively
1854 input and outputs that hasn't been handled. Such overlap
1855 should have been detected and reported above. */
1856 if (!clobber_conflict_found)
1860 /* We test the old body (obody) contents to avoid tripping
1861 over the under-construction body. */
1862 for (opno = 0; opno < noutputs; opno++)
1863 if (reg_overlap_mentioned_p (clobbered_reg, output_rtx[opno]))
1864 internal_error ("asm clobber conflict with output operand");
1866 for (opno = 0; opno < ninputs - ninout; opno++)
1867 if (reg_overlap_mentioned_p (clobbered_reg,
1868 ASM_OPERANDS_INPUT (obody, opno)))
1869 internal_error ("asm clobber conflict with input operand");
1872 XVECEXP (body, 0, i++)
1873 = gen_rtx_CLOBBER (VOIDmode, clobbered_reg);
1879 /* For any outputs that needed reloading into registers, spill them
1880 back to where they belong. */
1881 for (i = 0; i < noutputs; ++i)
1882 if (real_output_rtx[i])
1883 emit_move_insn (real_output_rtx[i], output_rtx[i]);
1888 /* A subroutine of expand_asm_operands. Check that all operands have
1889 the same number of alternatives. Return true if so. */
1892 check_operand_nalternatives (tree outputs, tree inputs)
1894 if (outputs || inputs)
1896 tree tmp = TREE_PURPOSE (outputs ? outputs : inputs);
1898 = n_occurrences (',', TREE_STRING_POINTER (TREE_VALUE (tmp)));
1901 if (nalternatives + 1 > MAX_RECOG_ALTERNATIVES)
1903 error ("too many alternatives in `asm'");
1910 const char *constraint
1911 = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tmp)));
1913 if (n_occurrences (',', constraint) != nalternatives)
1915 error ("operand constraints for `asm' differ in number of alternatives");
1919 if (TREE_CHAIN (tmp))
1920 tmp = TREE_CHAIN (tmp);
1922 tmp = next, next = 0;
1929 /* A subroutine of expand_asm_operands. Check that all operand names
1930 are unique. Return true if so. We rely on the fact that these names
1931 are identifiers, and so have been canonicalized by get_identifier,
1932 so all we need are pointer comparisons. */
1935 check_unique_operand_names (tree outputs, tree inputs)
1939 for (i = outputs; i ; i = TREE_CHAIN (i))
1941 tree i_name = TREE_PURPOSE (TREE_PURPOSE (i));
1945 for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
1946 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1950 for (i = inputs; i ; i = TREE_CHAIN (i))
1952 tree i_name = TREE_PURPOSE (TREE_PURPOSE (i));
1956 for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
1957 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1959 for (j = outputs; j ; j = TREE_CHAIN (j))
1960 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1967 error ("duplicate asm operand name '%s'",
1968 TREE_STRING_POINTER (TREE_PURPOSE (TREE_PURPOSE (i))));
1972 /* A subroutine of expand_asm_operands. Resolve the names of the operands
1973 in *POUTPUTS and *PINPUTS to numbers, and replace the name expansions in
1974 STRING and in the constraints to those numbers. */
1977 resolve_asm_operand_names (tree string, tree outputs, tree inputs)
1984 check_unique_operand_names (outputs, inputs);
1986 /* Substitute [<name>] in input constraint strings. There should be no
1987 named operands in output constraints. */
1988 for (t = inputs; t ; t = TREE_CHAIN (t))
1990 c = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
1991 if (strchr (c, '[') != NULL)
1993 p = buffer = xstrdup (c);
1994 while ((p = strchr (p, '[')) != NULL)
1995 p = resolve_operand_name_1 (p, outputs, inputs);
1996 TREE_VALUE (TREE_PURPOSE (t))
1997 = build_string (strlen (buffer), buffer);
2002 /* Now check for any needed substitutions in the template. */
2003 c = TREE_STRING_POINTER (string);
2004 while ((c = strchr (c, '%')) != NULL)
2008 else if (ISALPHA (c[1]) && c[2] == '[')
2019 /* OK, we need to make a copy so we can perform the substitutions.
2020 Assume that we will not need extra space--we get to remove '['
2021 and ']', which means we cannot have a problem until we have more
2022 than 999 operands. */
2023 buffer = xstrdup (TREE_STRING_POINTER (string));
2024 p = buffer + (c - TREE_STRING_POINTER (string));
2026 while ((p = strchr (p, '%')) != NULL)
2030 else if (ISALPHA (p[1]) && p[2] == '[')
2038 p = resolve_operand_name_1 (p, outputs, inputs);
2041 string = build_string (strlen (buffer), buffer);
2048 /* A subroutine of resolve_operand_names. P points to the '[' for a
2049 potential named operand of the form [<name>]. In place, replace
2050 the name and brackets with a number. Return a pointer to the
2051 balance of the string after substitution. */
2054 resolve_operand_name_1 (char *p, tree outputs, tree inputs)
2061 /* Collect the operand name. */
2062 q = strchr (p, ']');
2065 error ("missing close brace for named operand");
2066 return strchr (p, '\0');
2070 /* Resolve the name to a number. */
2071 for (op = 0, t = outputs; t ; t = TREE_CHAIN (t), op++)
2073 tree name = TREE_PURPOSE (TREE_PURPOSE (t));
2076 const char *c = TREE_STRING_POINTER (name);
2077 if (strncmp (c, p + 1, len) == 0 && c[len] == '\0')
2081 for (t = inputs; t ; t = TREE_CHAIN (t), op++)
2083 tree name = TREE_PURPOSE (TREE_PURPOSE (t));
2086 const char *c = TREE_STRING_POINTER (name);
2087 if (strncmp (c, p + 1, len) == 0 && c[len] == '\0')
2093 error ("undefined named operand '%s'", p + 1);
2097 /* Replace the name with the number. Unfortunately, not all libraries
2098 get the return value of sprintf correct, so search for the end of the
2099 generated string by hand. */
2100 sprintf (p, "%d", op);
2101 p = strchr (p, '\0');
2103 /* Verify the no extra buffer space assumption. */
2107 /* Shift the rest of the buffer down to fill the gap. */
2108 memmove (p, q + 1, strlen (q + 1) + 1);
2113 /* Generate RTL to evaluate the expression EXP
2114 and remember it in case this is the VALUE in a ({... VALUE; }) constr.
2115 Provided just for backward-compatibility. expand_expr_stmt_value()
2116 should be used for new code. */
2119 expand_expr_stmt (tree exp)
2121 expand_expr_stmt_value (exp, -1, 1);
2124 /* Generate RTL to evaluate the expression EXP. WANT_VALUE tells
2125 whether to (1) save the value of the expression, (0) discard it or
2126 (-1) use expr_stmts_for_value to tell. The use of -1 is
2127 deprecated, and retained only for backward compatibility. */
2130 expand_expr_stmt_value (tree exp, int want_value, int maybe_last)
2135 if (want_value == -1)
2136 want_value = expr_stmts_for_value != 0;
2138 /* If -Wextra, warn about statements with no side effects,
2139 except for an explicit cast to void (e.g. for assert()), and
2140 except for last statement in ({...}) where they may be useful. */
2142 && (expr_stmts_for_value == 0 || ! maybe_last)
2143 && exp != error_mark_node
2144 && warn_unused_value)
2146 if (TREE_SIDE_EFFECTS (exp))
2147 warn_if_unused_value (exp);
2148 else if (!VOID_TYPE_P (TREE_TYPE (exp)))
2149 warning ("%Hstatement with no effect", &emit_locus);
2152 /* If EXP is of function type and we are expanding statements for
2153 value, convert it to pointer-to-function. */
2154 if (want_value && TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE)
2155 exp = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (exp)), exp);
2157 /* The call to `expand_expr' could cause last_expr_type and
2158 last_expr_value to get reset. Therefore, we set last_expr_value
2159 and last_expr_type *after* calling expand_expr. */
2160 value = expand_expr (exp, want_value ? NULL_RTX : const0_rtx,
2162 type = TREE_TYPE (exp);
2164 /* If all we do is reference a volatile value in memory,
2165 copy it to a register to be sure it is actually touched. */
2166 if (value && GET_CODE (value) == MEM && TREE_THIS_VOLATILE (exp))
2168 if (TYPE_MODE (type) == VOIDmode)
2170 else if (TYPE_MODE (type) != BLKmode)
2171 value = copy_to_reg (value);
2174 rtx lab = gen_label_rtx ();
2176 /* Compare the value with itself to reference it. */
2177 emit_cmp_and_jump_insns (value, value, EQ,
2178 expand_expr (TYPE_SIZE (type),
2179 NULL_RTX, VOIDmode, 0),
2185 /* If this expression is part of a ({...}) and is in memory, we may have
2186 to preserve temporaries. */
2187 preserve_temp_slots (value);
2189 /* Free any temporaries used to evaluate this expression. Any temporary
2190 used as a result of this expression will already have been preserved
2196 last_expr_value = value;
2197 last_expr_type = type;
2203 /* Warn if EXP contains any computations whose results are not used.
2204 Return 1 if a warning is printed; 0 otherwise. */
2207 warn_if_unused_value (tree exp)
2209 if (TREE_USED (exp))
2212 /* Don't warn about void constructs. This includes casting to void,
2213 void function calls, and statement expressions with a final cast
2215 if (VOID_TYPE_P (TREE_TYPE (exp)))
2218 switch (TREE_CODE (exp))
2220 case PREINCREMENT_EXPR:
2221 case POSTINCREMENT_EXPR:
2222 case PREDECREMENT_EXPR:
2223 case POSTDECREMENT_EXPR:
2229 case TRY_CATCH_EXPR:
2230 case WITH_CLEANUP_EXPR:
2235 /* For a binding, warn if no side effect within it. */
2236 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2239 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2241 case TRUTH_ORIF_EXPR:
2242 case TRUTH_ANDIF_EXPR:
2243 /* In && or ||, warn if 2nd operand has no side effect. */
2244 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2247 if (TREE_NO_UNUSED_WARNING (exp))
2249 if (warn_if_unused_value (TREE_OPERAND (exp, 0)))
2251 /* Let people do `(foo (), 0)' without a warning. */
2252 if (TREE_CONSTANT (TREE_OPERAND (exp, 1)))
2254 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2258 case NON_LVALUE_EXPR:
2259 /* Don't warn about conversions not explicit in the user's program. */
2260 if (TREE_NO_UNUSED_WARNING (exp))
2262 /* Assignment to a cast usually results in a cast of a modify.
2263 Don't complain about that. There can be an arbitrary number of
2264 casts before the modify, so we must loop until we find the first
2265 non-cast expression and then test to see if that is a modify. */
2267 tree tem = TREE_OPERAND (exp, 0);
2269 while (TREE_CODE (tem) == CONVERT_EXPR || TREE_CODE (tem) == NOP_EXPR)
2270 tem = TREE_OPERAND (tem, 0);
2272 if (TREE_CODE (tem) == MODIFY_EXPR || TREE_CODE (tem) == INIT_EXPR
2273 || TREE_CODE (tem) == CALL_EXPR)
2279 /* Don't warn about automatic dereferencing of references, since
2280 the user cannot control it. */
2281 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (exp, 0))) == REFERENCE_TYPE)
2282 return warn_if_unused_value (TREE_OPERAND (exp, 0));
2286 /* Referencing a volatile value is a side effect, so don't warn. */
2288 || TREE_CODE_CLASS (TREE_CODE (exp)) == 'r')
2289 && TREE_THIS_VOLATILE (exp))
2292 /* If this is an expression which has no operands, there is no value
2293 to be unused. There are no such language-independent codes,
2294 but front ends may define such. */
2295 if (TREE_CODE_CLASS (TREE_CODE (exp)) == 'e'
2296 && TREE_CODE_LENGTH (TREE_CODE (exp)) == 0)
2300 /* If this is an expression with side effects, don't warn. */
2301 if (TREE_SIDE_EFFECTS (exp))
2304 warning ("%Hvalue computed is not used", &emit_locus);
2309 /* Clear out the memory of the last expression evaluated. */
2312 clear_last_expr (void)
2314 last_expr_type = NULL_TREE;
2315 last_expr_value = NULL_RTX;
2318 /* Begin a statement-expression, i.e., a series of statements which
2319 may return a value. Return the RTL_EXPR for this statement expr.
2320 The caller must save that value and pass it to
2321 expand_end_stmt_expr. If HAS_SCOPE is nonzero, temporaries created
2322 in the statement-expression are deallocated at the end of the
2326 expand_start_stmt_expr (int has_scope)
2330 /* Make the RTL_EXPR node temporary, not momentary,
2331 so that rtl_expr_chain doesn't become garbage. */
2332 t = make_node (RTL_EXPR);
2333 do_pending_stack_adjust ();
2335 start_sequence_for_rtl_expr (t);
2339 expr_stmts_for_value++;
2343 /* Restore the previous state at the end of a statement that returns a value.
2344 Returns a tree node representing the statement's value and the
2345 insns to compute the value.
2347 The nodes of that expression have been freed by now, so we cannot use them.
2348 But we don't want to do that anyway; the expression has already been
2349 evaluated and now we just want to use the value. So generate a RTL_EXPR
2350 with the proper type and RTL value.
2352 If the last substatement was not an expression,
2353 return something with type `void'. */
2356 expand_end_stmt_expr (tree t)
2360 if (! last_expr_value || ! last_expr_type)
2362 last_expr_value = const0_rtx;
2363 last_expr_type = void_type_node;
2365 else if (GET_CODE (last_expr_value) != REG && ! CONSTANT_P (last_expr_value))
2366 /* Remove any possible QUEUED. */
2367 last_expr_value = protect_from_queue (last_expr_value, 0);
2371 TREE_TYPE (t) = last_expr_type;
2372 RTL_EXPR_RTL (t) = last_expr_value;
2373 RTL_EXPR_SEQUENCE (t) = get_insns ();
2375 rtl_expr_chain = tree_cons (NULL_TREE, t, rtl_expr_chain);
2379 /* Don't consider deleting this expr or containing exprs at tree level. */
2380 TREE_SIDE_EFFECTS (t) = 1;
2381 /* Propagate volatility of the actual RTL expr. */
2382 TREE_THIS_VOLATILE (t) = volatile_refs_p (last_expr_value);
2385 expr_stmts_for_value--;
2390 /* Generate RTL for the start of an if-then. COND is the expression
2391 whose truth should be tested.
2393 If EXITFLAG is nonzero, this conditional is visible to
2394 `exit_something'. */
2397 expand_start_cond (tree cond, int exitflag)
2399 struct nesting *thiscond = ALLOC_NESTING ();
2401 /* Make an entry on cond_stack for the cond we are entering. */
2403 thiscond->desc = COND_NESTING;
2404 thiscond->next = cond_stack;
2405 thiscond->all = nesting_stack;
2406 thiscond->depth = ++nesting_depth;
2407 thiscond->data.cond.next_label = gen_label_rtx ();
2408 /* Before we encounter an `else', we don't need a separate exit label
2409 unless there are supposed to be exit statements
2410 to exit this conditional. */
2411 thiscond->exit_label = exitflag ? gen_label_rtx () : 0;
2412 thiscond->data.cond.endif_label = thiscond->exit_label;
2413 cond_stack = thiscond;
2414 nesting_stack = thiscond;
2416 do_jump (cond, thiscond->data.cond.next_label, NULL_RTX);
2419 /* Generate RTL between then-clause and the elseif-clause
2420 of an if-then-elseif-.... */
2423 expand_start_elseif (tree cond)
2425 if (cond_stack->data.cond.endif_label == 0)
2426 cond_stack->data.cond.endif_label = gen_label_rtx ();
2427 emit_jump (cond_stack->data.cond.endif_label);
2428 emit_label (cond_stack->data.cond.next_label);
2429 cond_stack->data.cond.next_label = gen_label_rtx ();
2430 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
2433 /* Generate RTL between the then-clause and the else-clause
2434 of an if-then-else. */
2437 expand_start_else (void)
2439 if (cond_stack->data.cond.endif_label == 0)
2440 cond_stack->data.cond.endif_label = gen_label_rtx ();
2442 emit_jump (cond_stack->data.cond.endif_label);
2443 emit_label (cond_stack->data.cond.next_label);
2444 cond_stack->data.cond.next_label = 0; /* No more _else or _elseif calls. */
2447 /* After calling expand_start_else, turn this "else" into an "else if"
2448 by providing another condition. */
2451 expand_elseif (tree cond)
2453 cond_stack->data.cond.next_label = gen_label_rtx ();
2454 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
2457 /* Generate RTL for the end of an if-then.
2458 Pop the record for it off of cond_stack. */
2461 expand_end_cond (void)
2463 struct nesting *thiscond = cond_stack;
2465 do_pending_stack_adjust ();
2466 if (thiscond->data.cond.next_label)
2467 emit_label (thiscond->data.cond.next_label);
2468 if (thiscond->data.cond.endif_label)
2469 emit_label (thiscond->data.cond.endif_label);
2471 POPSTACK (cond_stack);
2475 /* Generate RTL for the start of a loop. EXIT_FLAG is nonzero if this
2476 loop should be exited by `exit_something'. This is a loop for which
2477 `expand_continue' will jump to the top of the loop.
2479 Make an entry on loop_stack to record the labels associated with
2483 expand_start_loop (int exit_flag)
2485 struct nesting *thisloop = ALLOC_NESTING ();
2487 /* Make an entry on loop_stack for the loop we are entering. */
2489 thisloop->desc = LOOP_NESTING;
2490 thisloop->next = loop_stack;
2491 thisloop->all = nesting_stack;
2492 thisloop->depth = ++nesting_depth;
2493 thisloop->data.loop.start_label = gen_label_rtx ();
2494 thisloop->data.loop.end_label = gen_label_rtx ();
2495 thisloop->data.loop.continue_label = thisloop->data.loop.start_label;
2496 thisloop->exit_label = exit_flag ? thisloop->data.loop.end_label : 0;
2497 loop_stack = thisloop;
2498 nesting_stack = thisloop;
2500 do_pending_stack_adjust ();
2502 emit_note (NOTE_INSN_LOOP_BEG);
2503 emit_label (thisloop->data.loop.start_label);
2508 /* Like expand_start_loop but for a loop where the continuation point
2509 (for expand_continue_loop) will be specified explicitly. */
2512 expand_start_loop_continue_elsewhere (int exit_flag)
2514 struct nesting *thisloop = expand_start_loop (exit_flag);
2515 loop_stack->data.loop.continue_label = gen_label_rtx ();
2519 /* Begin a null, aka do { } while (0) "loop". But since the contents
2520 of said loop can still contain a break, we must frob the loop nest. */
2523 expand_start_null_loop (void)
2525 struct nesting *thisloop = ALLOC_NESTING ();
2527 /* Make an entry on loop_stack for the loop we are entering. */
2529 thisloop->desc = LOOP_NESTING;
2530 thisloop->next = loop_stack;
2531 thisloop->all = nesting_stack;
2532 thisloop->depth = ++nesting_depth;
2533 thisloop->data.loop.start_label = emit_note (NOTE_INSN_DELETED);
2534 thisloop->data.loop.end_label = gen_label_rtx ();
2535 thisloop->data.loop.continue_label = thisloop->data.loop.end_label;
2536 thisloop->exit_label = thisloop->data.loop.end_label;
2537 loop_stack = thisloop;
2538 nesting_stack = thisloop;
2543 /* Specify the continuation point for a loop started with
2544 expand_start_loop_continue_elsewhere.
2545 Use this at the point in the code to which a continue statement
2549 expand_loop_continue_here (void)
2551 do_pending_stack_adjust ();
2552 emit_note (NOTE_INSN_LOOP_CONT);
2553 emit_label (loop_stack->data.loop.continue_label);
2556 /* Finish a loop. Generate a jump back to the top and the loop-exit label.
2557 Pop the block off of loop_stack. */
2560 expand_end_loop (void)
2562 rtx start_label = loop_stack->data.loop.start_label;
2564 int eh_regions, debug_blocks;
2567 /* Mark the continue-point at the top of the loop if none elsewhere. */
2568 if (start_label == loop_stack->data.loop.continue_label)
2569 emit_note_before (NOTE_INSN_LOOP_CONT, start_label);
2571 do_pending_stack_adjust ();
2573 /* If the loop starts with a loop exit, roll that to the end where
2574 it will optimize together with the jump back.
2576 If the loop presently looks like this (in pseudo-C):
2580 if (test) goto end_label;
2586 transform it to look like:
2593 if (test) goto end_label;
2597 We rely on the presence of NOTE_INSN_LOOP_END_TOP_COND to mark
2598 the end of the entry conditional. Without this, our lexical scan
2599 can't tell the difference between an entry conditional and a
2600 body conditional that exits the loop. Mistaking the two means
2601 that we can misplace the NOTE_INSN_LOOP_CONT note, which can
2602 screw up loop unrolling.
2604 Things will be oh so much better when loop optimization is done
2605 off of a proper control flow graph... */
2607 /* Scan insns from the top of the loop looking for the END_TOP_COND note. */
2610 eh_regions = debug_blocks = 0;
2611 for (etc_note = start_label; etc_note ; etc_note = NEXT_INSN (etc_note))
2612 if (GET_CODE (etc_note) == NOTE)
2614 if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_LOOP_END_TOP_COND)
2617 /* We must not walk into a nested loop. */
2618 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_LOOP_BEG)
2620 etc_note = NULL_RTX;
2624 /* At the same time, scan for EH region notes, as we don't want
2625 to scrog region nesting. This shouldn't happen, but... */
2626 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_EH_REGION_BEG)
2628 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_EH_REGION_END)
2630 if (--eh_regions < 0)
2631 /* We've come to the end of an EH region, but never saw the
2632 beginning of that region. That means that an EH region
2633 begins before the top of the loop, and ends in the middle
2634 of it. The existence of such a situation violates a basic
2635 assumption in this code, since that would imply that even
2636 when EH_REGIONS is zero, we might move code out of an
2637 exception region. */
2641 /* Likewise for debug scopes. In this case we'll either (1) move
2642 all of the notes if they are properly nested or (2) leave the
2643 notes alone and only rotate the loop at high optimization
2644 levels when we expect to scrog debug info. */
2645 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_BLOCK_BEG)
2647 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_BLOCK_END)
2650 else if (INSN_P (etc_note))
2657 && (debug_blocks == 0 || optimize >= 2)
2658 && NEXT_INSN (etc_note) != NULL_RTX
2659 && ! any_condjump_p (get_last_insn ()))
2661 /* We found one. Move everything from START to ETC to the end
2662 of the loop, and add a jump from the top of the loop. */
2663 rtx top_label = gen_label_rtx ();
2664 rtx start_move = start_label;
2666 /* If the start label is preceded by a NOTE_INSN_LOOP_CONT note,
2667 then we want to move this note also. */
2668 if (GET_CODE (PREV_INSN (start_move)) == NOTE
2669 && NOTE_LINE_NUMBER (PREV_INSN (start_move)) == NOTE_INSN_LOOP_CONT)
2670 start_move = PREV_INSN (start_move);
2672 emit_label_before (top_label, start_move);
2674 /* Actually move the insns. If the debug scopes are nested, we
2675 can move everything at once. Otherwise we have to move them
2676 one by one and squeeze out the block notes. */
2677 if (debug_blocks == 0)
2678 reorder_insns (start_move, etc_note, get_last_insn ());
2681 rtx insn, next_insn;
2682 for (insn = start_move; insn; insn = next_insn)
2684 /* Figure out which insn comes after this one. We have
2685 to do this before we move INSN. */
2686 next_insn = (insn == etc_note ? NULL : NEXT_INSN (insn));
2688 if (GET_CODE (insn) == NOTE
2689 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
2690 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
2693 reorder_insns (insn, insn, get_last_insn ());
2697 /* Add the jump from the top of the loop. */
2698 emit_jump_insn_before (gen_jump (start_label), top_label);
2699 emit_barrier_before (top_label);
2700 start_label = top_label;
2703 emit_jump (start_label);
2704 emit_note (NOTE_INSN_LOOP_END);
2705 emit_label (loop_stack->data.loop.end_label);
2707 POPSTACK (loop_stack);
2712 /* Finish a null loop, aka do { } while (0). */
2715 expand_end_null_loop (void)
2717 do_pending_stack_adjust ();
2718 emit_label (loop_stack->data.loop.end_label);
2720 POPSTACK (loop_stack);
2725 /* Generate a jump to the current loop's continue-point.
2726 This is usually the top of the loop, but may be specified
2727 explicitly elsewhere. If not currently inside a loop,
2728 return 0 and do nothing; caller will print an error message. */
2731 expand_continue_loop (struct nesting *whichloop)
2733 /* Emit information for branch prediction. */
2736 if (flag_guess_branch_prob)
2738 note = emit_note (NOTE_INSN_PREDICTION);
2739 NOTE_PREDICTION (note) = NOTE_PREDICT (PRED_CONTINUE, IS_TAKEN);
2743 whichloop = loop_stack;
2746 expand_goto_internal (NULL_TREE, whichloop->data.loop.continue_label,
2751 /* Generate a jump to exit the current loop. If not currently inside a loop,
2752 return 0 and do nothing; caller will print an error message. */
2755 expand_exit_loop (struct nesting *whichloop)
2759 whichloop = loop_stack;
2762 expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label, NULL_RTX);
2766 /* Generate a conditional jump to exit the current loop if COND
2767 evaluates to zero. If not currently inside a loop,
2768 return 0 and do nothing; caller will print an error message. */
2771 expand_exit_loop_if_false (struct nesting *whichloop, tree cond)
2777 whichloop = loop_stack;
2781 if (integer_nonzerop (cond))
2783 if (integer_zerop (cond))
2784 return expand_exit_loop (whichloop);
2786 /* Check if we definitely won't need a fixup. */
2787 if (whichloop == nesting_stack)
2789 jumpifnot (cond, whichloop->data.loop.end_label);
2793 /* In order to handle fixups, we actually create a conditional jump
2794 around an unconditional branch to exit the loop. If fixups are
2795 necessary, they go before the unconditional branch. */
2797 label = gen_label_rtx ();
2798 jumpif (cond, label);
2799 expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label,
2806 /* Like expand_exit_loop_if_false except also emit a note marking
2807 the end of the conditional. Should only be used immediately
2808 after expand_loop_start. */
2811 expand_exit_loop_top_cond (struct nesting *whichloop, tree cond)
2813 if (! expand_exit_loop_if_false (whichloop, cond))
2816 emit_note (NOTE_INSN_LOOP_END_TOP_COND);
2820 /* Return nonzero if we should preserve sub-expressions as separate
2821 pseudos. We never do so if we aren't optimizing. We always do so
2822 if -fexpensive-optimizations.
2824 Otherwise, we only do so if we are in the "early" part of a loop. I.e.,
2825 the loop may still be a small one. */
2828 preserve_subexpressions_p (void)
2832 if (flag_expensive_optimizations)
2835 if (optimize == 0 || cfun == 0 || cfun->stmt == 0 || loop_stack == 0)
2838 insn = get_last_insn_anywhere ();
2841 && (INSN_UID (insn) - INSN_UID (loop_stack->data.loop.start_label)
2842 < n_non_fixed_regs * 3));
2846 /* Generate a jump to exit the current loop, conditional, binding contour
2847 or case statement. Not all such constructs are visible to this function,
2848 only those started with EXIT_FLAG nonzero. Individual languages use
2849 the EXIT_FLAG parameter to control which kinds of constructs you can
2852 If not currently inside anything that can be exited,
2853 return 0 and do nothing; caller will print an error message. */
2856 expand_exit_something (void)
2860 for (n = nesting_stack; n; n = n->all)
2861 if (n->exit_label != 0)
2863 expand_goto_internal (NULL_TREE, n->exit_label, NULL_RTX);
2870 /* Generate RTL to return from the current function, with no value.
2871 (That is, we do not do anything about returning any value.) */
2874 expand_null_return (void)
2878 last_insn = get_last_insn ();
2880 /* If this function was declared to return a value, but we
2881 didn't, clobber the return registers so that they are not
2882 propagated live to the rest of the function. */
2883 clobber_return_register ();
2885 expand_null_return_1 (last_insn);
2888 /* Generate RTL to return directly from the current function.
2889 (That is, we bypass any return value.) */
2892 expand_naked_return (void)
2894 rtx last_insn, end_label;
2896 last_insn = get_last_insn ();
2897 end_label = naked_return_label;
2899 clear_pending_stack_adjust ();
2900 do_pending_stack_adjust ();
2904 end_label = naked_return_label = gen_label_rtx ();
2905 expand_goto_internal (NULL_TREE, end_label, last_insn);
2908 /* Try to guess whether the value of return means error code. */
2909 static enum br_predictor
2910 return_prediction (rtx val)
2912 /* Different heuristics for pointers and scalars. */
2913 if (POINTER_TYPE_P (TREE_TYPE (DECL_RESULT (current_function_decl))))
2915 /* NULL is usually not returned. */
2916 if (val == const0_rtx)
2917 return PRED_NULL_RETURN;
2921 /* Negative return values are often used to indicate
2923 if (GET_CODE (val) == CONST_INT
2924 && INTVAL (val) < 0)
2925 return PRED_NEGATIVE_RETURN;
2926 /* Constant return values are also usually erors,
2927 zero/one often mean booleans so exclude them from the
2929 if (CONSTANT_P (val)
2930 && (val != const0_rtx && val != const1_rtx))
2931 return PRED_CONST_RETURN;
2933 return PRED_NO_PREDICTION;
2937 /* If the current function returns values in the most significant part
2938 of a register, shift return value VAL appropriately. The mode of
2939 the function's return type is known not to be BLKmode. */
2942 shift_return_value (rtx val)
2946 type = TREE_TYPE (DECL_RESULT (current_function_decl));
2947 if (targetm.calls.return_in_msb (type))
2950 HOST_WIDE_INT shift;
2952 target = DECL_RTL (DECL_RESULT (current_function_decl));
2953 shift = (GET_MODE_BITSIZE (GET_MODE (target))
2954 - BITS_PER_UNIT * int_size_in_bytes (type));
2956 val = expand_binop (GET_MODE (target), ashl_optab,
2957 gen_lowpart (GET_MODE (target), val),
2958 GEN_INT (shift), target, 1, OPTAB_WIDEN);
2964 /* Generate RTL to return from the current function, with value VAL. */
2967 expand_value_return (rtx val)
2971 enum br_predictor pred;
2973 if (flag_guess_branch_prob
2974 && (pred = return_prediction (val)) != PRED_NO_PREDICTION)
2976 /* Emit information for branch prediction. */
2979 note = emit_note (NOTE_INSN_PREDICTION);
2981 NOTE_PREDICTION (note) = NOTE_PREDICT (pred, NOT_TAKEN);
2985 last_insn = get_last_insn ();
2986 return_reg = DECL_RTL (DECL_RESULT (current_function_decl));
2988 /* Copy the value to the return location
2989 unless it's already there. */
2991 if (return_reg != val)
2993 tree type = TREE_TYPE (DECL_RESULT (current_function_decl));
2994 if (targetm.calls.promote_function_return (TREE_TYPE (current_function_decl)))
2996 int unsignedp = TREE_UNSIGNED (type);
2997 enum machine_mode old_mode
2998 = DECL_MODE (DECL_RESULT (current_function_decl));
2999 enum machine_mode mode
3000 = promote_mode (type, old_mode, &unsignedp, 1);
3002 if (mode != old_mode)
3003 val = convert_modes (mode, old_mode, val, unsignedp);
3005 if (GET_CODE (return_reg) == PARALLEL)
3006 emit_group_load (return_reg, val, type, int_size_in_bytes (type));
3008 emit_move_insn (return_reg, val);
3011 expand_null_return_1 (last_insn);
3014 /* Output a return with no value. If LAST_INSN is nonzero,
3015 pretend that the return takes place after LAST_INSN. */
3018 expand_null_return_1 (rtx last_insn)
3020 rtx end_label = cleanup_label ? cleanup_label : return_label;
3022 clear_pending_stack_adjust ();
3023 do_pending_stack_adjust ();
3027 end_label = return_label = gen_label_rtx ();
3028 expand_goto_internal (NULL_TREE, end_label, last_insn);
3031 /* Generate RTL to evaluate the expression RETVAL and return it
3032 from the current function. */
3035 expand_return (tree retval)
3037 /* If there are any cleanups to be performed, then they will
3038 be inserted following LAST_INSN. It is desirable
3039 that the last_insn, for such purposes, should be the
3040 last insn before computing the return value. Otherwise, cleanups
3041 which call functions can clobber the return value. */
3042 /* ??? rms: I think that is erroneous, because in C++ it would
3043 run destructors on variables that might be used in the subsequent
3044 computation of the return value. */
3050 /* If function wants no value, give it none. */
3051 if (TREE_CODE (TREE_TYPE (TREE_TYPE (current_function_decl))) == VOID_TYPE)
3053 expand_expr (retval, NULL_RTX, VOIDmode, 0);
3055 expand_null_return ();
3059 if (retval == error_mark_node)
3061 /* Treat this like a return of no value from a function that
3063 expand_null_return ();
3066 else if (TREE_CODE (retval) == RESULT_DECL)
3067 retval_rhs = retval;
3068 else if ((TREE_CODE (retval) == MODIFY_EXPR || TREE_CODE (retval) == INIT_EXPR)
3069 && TREE_CODE (TREE_OPERAND (retval, 0)) == RESULT_DECL)
3070 retval_rhs = TREE_OPERAND (retval, 1);
3071 else if (VOID_TYPE_P (TREE_TYPE (retval)))
3072 /* Recognize tail-recursive call to void function. */
3073 retval_rhs = retval;
3075 retval_rhs = NULL_TREE;
3077 last_insn = get_last_insn ();
3079 /* Distribute return down conditional expr if either of the sides
3080 may involve tail recursion (see test below). This enhances the number
3081 of tail recursions we see. Don't do this always since it can produce
3082 sub-optimal code in some cases and we distribute assignments into
3083 conditional expressions when it would help. */
3085 if (optimize && retval_rhs != 0
3086 && frame_offset == 0
3087 && TREE_CODE (retval_rhs) == COND_EXPR
3088 && (TREE_CODE (TREE_OPERAND (retval_rhs, 1)) == CALL_EXPR
3089 || TREE_CODE (TREE_OPERAND (retval_rhs, 2)) == CALL_EXPR))
3091 rtx label = gen_label_rtx ();
3094 do_jump (TREE_OPERAND (retval_rhs, 0), label, NULL_RTX);
3095 start_cleanup_deferral ();
3096 expr = build (MODIFY_EXPR, TREE_TYPE (TREE_TYPE (current_function_decl)),
3097 DECL_RESULT (current_function_decl),
3098 TREE_OPERAND (retval_rhs, 1));
3099 TREE_SIDE_EFFECTS (expr) = 1;
3100 expand_return (expr);
3103 expr = build (MODIFY_EXPR, TREE_TYPE (TREE_TYPE (current_function_decl)),
3104 DECL_RESULT (current_function_decl),
3105 TREE_OPERAND (retval_rhs, 2));
3106 TREE_SIDE_EFFECTS (expr) = 1;
3107 expand_return (expr);
3108 end_cleanup_deferral ();
3112 result_rtl = DECL_RTL (DECL_RESULT (current_function_decl));
3114 /* If the result is an aggregate that is being returned in one (or more)
3115 registers, load the registers here. The compiler currently can't handle
3116 copying a BLKmode value into registers. We could put this code in a
3117 more general area (for use by everyone instead of just function
3118 call/return), but until this feature is generally usable it is kept here
3119 (and in expand_call). The value must go into a pseudo in case there
3120 are cleanups that will clobber the real return register. */
3123 && TYPE_MODE (TREE_TYPE (retval_rhs)) == BLKmode
3124 && GET_CODE (result_rtl) == REG)
3127 unsigned HOST_WIDE_INT bitpos, xbitpos;
3128 unsigned HOST_WIDE_INT padding_correction = 0;
3129 unsigned HOST_WIDE_INT bytes
3130 = int_size_in_bytes (TREE_TYPE (retval_rhs));
3131 int n_regs = (bytes + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
3132 unsigned int bitsize
3133 = MIN (TYPE_ALIGN (TREE_TYPE (retval_rhs)), BITS_PER_WORD);
3134 rtx *result_pseudos = alloca (sizeof (rtx) * n_regs);
3135 rtx result_reg, src = NULL_RTX, dst = NULL_RTX;
3136 rtx result_val = expand_expr (retval_rhs, NULL_RTX, VOIDmode, 0);
3137 enum machine_mode tmpmode, result_reg_mode;
3141 expand_null_return ();
3145 /* If the structure doesn't take up a whole number of words, see
3146 whether the register value should be padded on the left or on
3147 the right. Set PADDING_CORRECTION to the number of padding
3148 bits needed on the left side.
3150 In most ABIs, the structure will be returned at the least end of
3151 the register, which translates to right padding on little-endian
3152 targets and left padding on big-endian targets. The opposite
3153 holds if the structure is returned at the most significant
3154 end of the register. */
3155 if (bytes % UNITS_PER_WORD != 0
3156 && (targetm.calls.return_in_msb (TREE_TYPE (retval_rhs))
3158 : BYTES_BIG_ENDIAN))
3159 padding_correction = (BITS_PER_WORD - ((bytes % UNITS_PER_WORD)
3162 /* Copy the structure BITSIZE bits at a time. */
3163 for (bitpos = 0, xbitpos = padding_correction;
3164 bitpos < bytes * BITS_PER_UNIT;
3165 bitpos += bitsize, xbitpos += bitsize)
3167 /* We need a new destination pseudo each time xbitpos is
3168 on a word boundary and when xbitpos == padding_correction
3169 (the first time through). */
3170 if (xbitpos % BITS_PER_WORD == 0
3171 || xbitpos == padding_correction)
3173 /* Generate an appropriate register. */
3174 dst = gen_reg_rtx (word_mode);
3175 result_pseudos[xbitpos / BITS_PER_WORD] = dst;
3177 /* Clear the destination before we move anything into it. */
3178 emit_move_insn (dst, CONST0_RTX (GET_MODE (dst)));
3181 /* We need a new source operand each time bitpos is on a word
3183 if (bitpos % BITS_PER_WORD == 0)
3184 src = operand_subword_force (result_val,
3185 bitpos / BITS_PER_WORD,
3188 /* Use bitpos for the source extraction (left justified) and
3189 xbitpos for the destination store (right justified). */
3190 store_bit_field (dst, bitsize, xbitpos % BITS_PER_WORD, word_mode,
3191 extract_bit_field (src, bitsize,
3192 bitpos % BITS_PER_WORD, 1,
3193 NULL_RTX, word_mode, word_mode,
3198 tmpmode = GET_MODE (result_rtl);
3199 if (tmpmode == BLKmode)
3201 /* Find the smallest integer mode large enough to hold the
3202 entire structure and use that mode instead of BLKmode
3203 on the USE insn for the return register. */
3204 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
3205 tmpmode != VOIDmode;
3206 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
3207 /* Have we found a large enough mode? */
3208 if (GET_MODE_SIZE (tmpmode) >= bytes)
3211 /* No suitable mode found. */
3212 if (tmpmode == VOIDmode)
3215 PUT_MODE (result_rtl, tmpmode);
3218 if (GET_MODE_SIZE (tmpmode) < GET_MODE_SIZE (word_mode))
3219 result_reg_mode = word_mode;
3221 result_reg_mode = tmpmode;
3222 result_reg = gen_reg_rtx (result_reg_mode);
3225 for (i = 0; i < n_regs; i++)
3226 emit_move_insn (operand_subword (result_reg, i, 0, result_reg_mode),
3229 if (tmpmode != result_reg_mode)
3230 result_reg = gen_lowpart (tmpmode, result_reg);
3232 expand_value_return (result_reg);
3234 else if (retval_rhs != 0
3235 && !VOID_TYPE_P (TREE_TYPE (retval_rhs))
3236 && (GET_CODE (result_rtl) == REG
3237 || (GET_CODE (result_rtl) == PARALLEL)))
3239 /* Calculate the return value into a temporary (usually a pseudo
3241 tree ot = TREE_TYPE (DECL_RESULT (current_function_decl));
3242 tree nt = build_qualified_type (ot, TYPE_QUALS (ot) | TYPE_QUAL_CONST);
3244 val = assign_temp (nt, 0, 0, 1);
3245 val = expand_expr (retval_rhs, val, GET_MODE (val), 0);
3246 val = force_not_mem (val);
3248 /* Return the calculated value, doing cleanups first. */
3249 expand_value_return (shift_return_value (val));
3253 /* No cleanups or no hard reg used;
3254 calculate value into hard return reg. */
3255 expand_expr (retval, const0_rtx, VOIDmode, 0);
3257 expand_value_return (result_rtl);
3261 /* Attempt to optimize a potential tail recursion call into a goto.
3262 ARGUMENTS are the arguments to a CALL_EXPR; LAST_INSN indicates
3263 where to place the jump to the tail recursion label.
3265 Return TRUE if the call was optimized into a goto. */
3268 optimize_tail_recursion (tree arguments, rtx last_insn)
3270 /* Finish checking validity, and if valid emit code to set the
3271 argument variables for the new call. */
3272 if (tail_recursion_args (arguments, DECL_ARGUMENTS (current_function_decl)))
3274 if (tail_recursion_label == 0)
3276 tail_recursion_label = gen_label_rtx ();
3277 emit_label_after (tail_recursion_label,
3278 tail_recursion_reentry);
3281 expand_goto_internal (NULL_TREE, tail_recursion_label, last_insn);
3288 /* Emit code to alter this function's formal parms for a tail-recursive call.
3289 ACTUALS is a list of actual parameter expressions (chain of TREE_LISTs).
3290 FORMALS is the chain of decls of formals.
3291 Return 1 if this can be done;
3292 otherwise return 0 and do not emit any code. */
3295 tail_recursion_args (tree actuals, tree formals)
3297 tree a = actuals, f = formals;
3301 /* Check that number and types of actuals are compatible
3302 with the formals. This is not always true in valid C code.
3303 Also check that no formal needs to be addressable
3304 and that all formals are scalars. */
3306 /* Also count the args. */
3308 for (a = actuals, f = formals, i = 0; a && f; a = TREE_CHAIN (a), f = TREE_CHAIN (f), i++)
3310 if (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_VALUE (a)))
3311 != TYPE_MAIN_VARIANT (TREE_TYPE (f)))
3313 if (GET_CODE (DECL_RTL (f)) != REG || DECL_MODE (f) == BLKmode)
3316 if (a != 0 || f != 0)
3319 /* Compute all the actuals. */
3321 argvec = alloca (i * sizeof (rtx));
3323 for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
3324 argvec[i] = expand_expr (TREE_VALUE (a), NULL_RTX, VOIDmode, 0);
3326 /* Find which actual values refer to current values of previous formals.
3327 Copy each of them now, before any formal is changed. */
3329 for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
3333 for (f = formals, j = 0; j < i; f = TREE_CHAIN (f), j++)
3334 if (reg_mentioned_p (DECL_RTL (f), argvec[i]))
3340 argvec[i] = copy_to_reg (argvec[i]);
3343 /* Store the values of the actuals into the formals. */
3345 for (f = formals, a = actuals, i = 0; f;
3346 f = TREE_CHAIN (f), a = TREE_CHAIN (a), i++)
3348 if (GET_MODE (DECL_RTL (f)) == GET_MODE (argvec[i]))
3349 emit_move_insn (DECL_RTL (f), argvec[i]);
3352 rtx tmp = argvec[i];
3353 int unsignedp = TREE_UNSIGNED (TREE_TYPE (TREE_VALUE (a)));
3354 promote_mode(TREE_TYPE (TREE_VALUE (a)), GET_MODE (tmp),
3356 if (DECL_MODE (f) != GET_MODE (DECL_RTL (f)))
3358 tmp = gen_reg_rtx (DECL_MODE (f));
3359 convert_move (tmp, argvec[i], unsignedp);
3361 convert_move (DECL_RTL (f), tmp, unsignedp);
3369 /* Generate the RTL code for entering a binding contour.
3370 The variables are declared one by one, by calls to `expand_decl'.
3372 FLAGS is a bitwise or of the following flags:
3374 1 - Nonzero if this construct should be visible to
3377 2 - Nonzero if this contour does not require a
3378 NOTE_INSN_BLOCK_BEG note. Virtually all calls from
3379 language-independent code should set this flag because they
3380 will not create corresponding BLOCK nodes. (There should be
3381 a one-to-one correspondence between NOTE_INSN_BLOCK_BEG notes
3382 and BLOCKs.) If this flag is set, MARK_ENDS should be zero
3383 when expand_end_bindings is called.
3385 If we are creating a NOTE_INSN_BLOCK_BEG note, a BLOCK may
3386 optionally be supplied. If so, it becomes the NOTE_BLOCK for the
3390 expand_start_bindings_and_block (int flags, tree block)
3392 struct nesting *thisblock = ALLOC_NESTING ();
3394 int exit_flag = ((flags & 1) != 0);
3395 int block_flag = ((flags & 2) == 0);
3397 /* If a BLOCK is supplied, then the caller should be requesting a
3398 NOTE_INSN_BLOCK_BEG note. */
3399 if (!block_flag && block)
3402 /* Create a note to mark the beginning of the block. */
3405 note = emit_note (NOTE_INSN_BLOCK_BEG);
3406 NOTE_BLOCK (note) = block;
3409 note = emit_note (NOTE_INSN_DELETED);
3411 /* Make an entry on block_stack for the block we are entering. */
3413 thisblock->desc = BLOCK_NESTING;
3414 thisblock->next = block_stack;
3415 thisblock->all = nesting_stack;
3416 thisblock->depth = ++nesting_depth;
3417 thisblock->data.block.stack_level = 0;
3418 thisblock->data.block.cleanups = 0;
3419 thisblock->data.block.exception_region = 0;
3420 thisblock->data.block.block_target_temp_slot_level = target_temp_slot_level;
3422 thisblock->data.block.conditional_code = 0;
3423 thisblock->data.block.last_unconditional_cleanup = note;
3424 /* When we insert instructions after the last unconditional cleanup,
3425 we don't adjust last_insn. That means that a later add_insn will
3426 clobber the instructions we've just added. The easiest way to
3427 fix this is to just insert another instruction here, so that the
3428 instructions inserted after the last unconditional cleanup are
3429 never the last instruction. */
3430 emit_note (NOTE_INSN_DELETED);
3433 && !(block_stack->data.block.cleanups == NULL_TREE
3434 && block_stack->data.block.outer_cleanups == NULL_TREE))
3435 thisblock->data.block.outer_cleanups
3436 = tree_cons (NULL_TREE, block_stack->data.block.cleanups,
3437 block_stack->data.block.outer_cleanups);
3439 thisblock->data.block.outer_cleanups = 0;
3440 thisblock->data.block.label_chain = 0;
3441 thisblock->data.block.innermost_stack_block = stack_block_stack;
3442 thisblock->data.block.first_insn = note;
3443 thisblock->data.block.block_start_count = ++current_block_start_count;
3444 thisblock->exit_label = exit_flag ? gen_label_rtx () : 0;
3445 block_stack = thisblock;
3446 nesting_stack = thisblock;
3448 /* Make a new level for allocating stack slots. */
3452 /* Specify the scope of temporaries created by TARGET_EXPRs. Similar
3453 to CLEANUP_POINT_EXPR, but handles cases when a series of calls to
3454 expand_expr are made. After we end the region, we know that all
3455 space for all temporaries that were created by TARGET_EXPRs will be
3456 destroyed and their space freed for reuse. */
3459 expand_start_target_temps (void)
3461 /* This is so that even if the result is preserved, the space
3462 allocated will be freed, as we know that it is no longer in use. */
3465 /* Start a new binding layer that will keep track of all cleanup
3466 actions to be performed. */
3467 expand_start_bindings (2);
3469 target_temp_slot_level = temp_slot_level;
3473 expand_end_target_temps (void)
3475 expand_end_bindings (NULL_TREE, 0, 0);
3477 /* This is so that even if the result is preserved, the space
3478 allocated will be freed, as we know that it is no longer in use. */
3482 /* Given a pointer to a BLOCK node return nonzero if (and only if) the node
3483 in question represents the outermost pair of curly braces (i.e. the "body
3484 block") of a function or method.
3486 For any BLOCK node representing a "body block" of a function or method, the
3487 BLOCK_SUPERCONTEXT of the node will point to another BLOCK node which
3488 represents the outermost (function) scope for the function or method (i.e.
3489 the one which includes the formal parameters). The BLOCK_SUPERCONTEXT of
3490 *that* node in turn will point to the relevant FUNCTION_DECL node. */
3493 is_body_block (tree stmt)
3495 if (lang_hooks.no_body_blocks)
3498 if (TREE_CODE (stmt) == BLOCK)
3500 tree parent = BLOCK_SUPERCONTEXT (stmt);
3502 if (parent && TREE_CODE (parent) == BLOCK)
3504 tree grandparent = BLOCK_SUPERCONTEXT (parent);
3506 if (grandparent && TREE_CODE (grandparent) == FUNCTION_DECL)
3514 /* True if we are currently emitting insns in an area of output code
3515 that is controlled by a conditional expression. This is used by
3516 the cleanup handling code to generate conditional cleanup actions. */
3519 conditional_context (void)
3521 return block_stack && block_stack->data.block.conditional_code;
3524 /* Return an opaque pointer to the current nesting level, so frontend code
3525 can check its own sanity. */
3528 current_nesting_level (void)
3530 return cfun ? block_stack : 0;
3533 /* Emit a handler label for a nonlocal goto handler.
3534 Also emit code to store the handler label in SLOT before BEFORE_INSN. */
3537 expand_nl_handler_label (rtx slot, rtx before_insn)
3540 rtx handler_label = gen_label_rtx ();
3542 /* Don't let cleanup_cfg delete the handler. */
3543 LABEL_PRESERVE_P (handler_label) = 1;
3546 emit_move_insn (slot, gen_rtx_LABEL_REF (Pmode, handler_label));
3547 insns = get_insns ();
3549 emit_insn_before (insns, before_insn);
3551 emit_label (handler_label);
3553 return handler_label;
3556 /* Emit code to restore vital registers at the beginning of a nonlocal goto
3559 expand_nl_goto_receiver (void)
3561 #ifdef HAVE_nonlocal_goto
3562 if (! HAVE_nonlocal_goto)
3564 /* First adjust our frame pointer to its actual value. It was
3565 previously set to the start of the virtual area corresponding to
3566 the stacked variables when we branched here and now needs to be
3567 adjusted to the actual hardware fp value.
3569 Assignments are to virtual registers are converted by
3570 instantiate_virtual_regs into the corresponding assignment
3571 to the underlying register (fp in this case) that makes
3572 the original assignment true.
3573 So the following insn will actually be
3574 decrementing fp by STARTING_FRAME_OFFSET. */
3575 emit_move_insn (virtual_stack_vars_rtx, hard_frame_pointer_rtx);
3577 #if ARG_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3578 if (fixed_regs[ARG_POINTER_REGNUM])
3580 #ifdef ELIMINABLE_REGS
3581 /* If the argument pointer can be eliminated in favor of the
3582 frame pointer, we don't need to restore it. We assume here
3583 that if such an elimination is present, it can always be used.
3584 This is the case on all known machines; if we don't make this
3585 assumption, we do unnecessary saving on many machines. */
3586 static const struct elims {const int from, to;} elim_regs[] = ELIMINABLE_REGS;
3589 for (i = 0; i < ARRAY_SIZE (elim_regs); i++)
3590 if (elim_regs[i].from == ARG_POINTER_REGNUM
3591 && elim_regs[i].to == HARD_FRAME_POINTER_REGNUM)
3594 if (i == ARRAY_SIZE (elim_regs))
3597 /* Now restore our arg pointer from the address at which it
3598 was saved in our stack frame. */
3599 emit_move_insn (virtual_incoming_args_rtx,
3600 copy_to_reg (get_arg_pointer_save_area (cfun)));
3605 #ifdef HAVE_nonlocal_goto_receiver
3606 if (HAVE_nonlocal_goto_receiver)
3607 emit_insn (gen_nonlocal_goto_receiver ());
3611 /* Make handlers for nonlocal gotos taking place in the function calls in
3615 expand_nl_goto_receivers (struct nesting *thisblock)
3618 rtx afterward = gen_label_rtx ();
3623 /* Record the handler address in the stack slot for that purpose,
3624 during this block, saving and restoring the outer value. */
3625 if (thisblock->next != 0)
3626 for (slot = nonlocal_goto_handler_slots; slot; slot = XEXP (slot, 1))
3628 rtx save_receiver = gen_reg_rtx (Pmode);
3629 emit_move_insn (XEXP (slot, 0), save_receiver);
3632 emit_move_insn (save_receiver, XEXP (slot, 0));
3633 insns = get_insns ();
3635 emit_insn_before (insns, thisblock->data.block.first_insn);
3638 /* Jump around the handlers; they run only when specially invoked. */
3639 emit_jump (afterward);
3641 /* Make a separate handler for each label. */
3642 link = nonlocal_labels;
3643 slot = nonlocal_goto_handler_slots;
3644 label_list = NULL_RTX;
3645 for (; link; link = TREE_CHAIN (link), slot = XEXP (slot, 1))
3646 /* Skip any labels we shouldn't be able to jump to from here,
3647 we generate one special handler for all of them below which just calls
3649 if (! DECL_TOO_LATE (TREE_VALUE (link)))
3652 lab = expand_nl_handler_label (XEXP (slot, 0),
3653 thisblock->data.block.first_insn);
3654 label_list = gen_rtx_EXPR_LIST (VOIDmode, lab, label_list);
3656 expand_nl_goto_receiver ();
3658 /* Jump to the "real" nonlocal label. */
3659 expand_goto (TREE_VALUE (link));
3662 /* A second pass over all nonlocal labels; this time we handle those
3663 we should not be able to jump to at this point. */
3664 link = nonlocal_labels;
3665 slot = nonlocal_goto_handler_slots;
3667 for (; link; link = TREE_CHAIN (link), slot = XEXP (slot, 1))
3668 if (DECL_TOO_LATE (TREE_VALUE (link)))
3671 lab = expand_nl_handler_label (XEXP (slot, 0),
3672 thisblock->data.block.first_insn);
3673 label_list = gen_rtx_EXPR_LIST (VOIDmode, lab, label_list);
3679 expand_nl_goto_receiver ();
3680 expand_builtin_trap ();
3683 nonlocal_goto_handler_labels = label_list;
3684 emit_label (afterward);
3687 /* Warn about any unused VARS (which may contain nodes other than
3688 VAR_DECLs, but such nodes are ignored). The nodes are connected
3689 via the TREE_CHAIN field. */
3692 warn_about_unused_variables (tree vars)
3696 if (warn_unused_variable)
3697 for (decl = vars; decl; decl = TREE_CHAIN (decl))
3698 if (TREE_CODE (decl) == VAR_DECL
3699 && ! TREE_USED (decl)
3700 && ! DECL_IN_SYSTEM_HEADER (decl)
3701 && DECL_NAME (decl) && ! DECL_ARTIFICIAL (decl))
3702 warning ("%Junused variable '%D'", decl, decl);
3705 /* Generate RTL code to terminate a binding contour.
3707 VARS is the chain of VAR_DECL nodes for the variables bound in this
3708 contour. There may actually be other nodes in this chain, but any
3709 nodes other than VAR_DECLS are ignored.
3711 MARK_ENDS is nonzero if we should put a note at the beginning
3712 and end of this binding contour.
3714 DONT_JUMP_IN is positive if it is not valid to jump into this contour,
3715 zero if we can jump into this contour only if it does not have a saved
3716 stack level, and negative if we are not to check for invalid use of
3717 labels (because the front end does that). */
3720 expand_end_bindings (tree vars, int mark_ends, int dont_jump_in)
3722 struct nesting *thisblock = block_stack;
3724 /* If any of the variables in this scope were not used, warn the
3726 warn_about_unused_variables (vars);
3728 if (thisblock->exit_label)
3730 do_pending_stack_adjust ();
3731 emit_label (thisblock->exit_label);
3734 /* If necessary, make handlers for nonlocal gotos taking
3735 place in the function calls in this block. */
3736 if (function_call_count != 0 && nonlocal_labels
3737 /* Make handler for outermost block
3738 if there were any nonlocal gotos to this function. */
3739 && (thisblock->next == 0 ? current_function_has_nonlocal_label
3740 /* Make handler for inner block if it has something
3741 special to do when you jump out of it. */
3742 : (thisblock->data.block.cleanups != 0
3743 || thisblock->data.block.stack_level != 0)))
3744 expand_nl_goto_receivers (thisblock);
3746 /* Don't allow jumping into a block that has a stack level.
3747 Cleanups are allowed, though. */
3748 if (dont_jump_in > 0
3749 || (dont_jump_in == 0 && thisblock->data.block.stack_level != 0))
3751 struct label_chain *chain;
3753 /* Any labels in this block are no longer valid to go to.
3754 Mark them to cause an error message. */
3755 for (chain = thisblock->data.block.label_chain; chain; chain = chain->next)
3757 DECL_TOO_LATE (chain->label) = 1;
3758 /* If any goto without a fixup came to this label,
3759 that must be an error, because gotos without fixups
3760 come from outside all saved stack-levels. */
3761 if (TREE_ADDRESSABLE (chain->label))
3762 error ("%Jlabel '%D' used before containing binding contour",
3763 chain->label, chain->label);
3767 /* Restore stack level in effect before the block
3768 (only if variable-size objects allocated). */
3769 /* Perform any cleanups associated with the block. */
3771 if (thisblock->data.block.stack_level != 0
3772 || thisblock->data.block.cleanups != 0)
3777 /* Don't let cleanups affect ({...}) constructs. */
3778 int old_expr_stmts_for_value = expr_stmts_for_value;
3779 rtx old_last_expr_value = last_expr_value;
3780 tree old_last_expr_type = last_expr_type;
3781 expr_stmts_for_value = 0;
3783 /* Only clean up here if this point can actually be reached. */
3784 insn = get_last_insn ();
3785 if (GET_CODE (insn) == NOTE)
3786 insn = prev_nonnote_insn (insn);
3787 reachable = (! insn || GET_CODE (insn) != BARRIER);
3789 /* Do the cleanups. */
3790 expand_cleanups (thisblock->data.block.cleanups, 0, reachable);
3792 do_pending_stack_adjust ();
3794 expr_stmts_for_value = old_expr_stmts_for_value;
3795 last_expr_value = old_last_expr_value;
3796 last_expr_type = old_last_expr_type;
3798 /* Restore the stack level. */
3800 if (reachable && thisblock->data.block.stack_level != 0)
3802 emit_stack_restore (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3803 thisblock->data.block.stack_level, NULL_RTX);
3804 if (nonlocal_goto_handler_slots != 0)
3805 emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level,
3809 /* Any gotos out of this block must also do these things.
3810 Also report any gotos with fixups that came to labels in this
3812 fixup_gotos (thisblock,
3813 thisblock->data.block.stack_level,
3814 thisblock->data.block.cleanups,
3815 thisblock->data.block.first_insn,
3819 /* Mark the beginning and end of the scope if requested.
3820 We do this now, after running cleanups on the variables
3821 just going out of scope, so they are in scope for their cleanups. */
3825 rtx note = emit_note (NOTE_INSN_BLOCK_END);
3826 NOTE_BLOCK (note) = NOTE_BLOCK (thisblock->data.block.first_insn);
3829 /* Get rid of the beginning-mark if we don't make an end-mark. */
3830 NOTE_LINE_NUMBER (thisblock->data.block.first_insn) = NOTE_INSN_DELETED;
3832 /* Restore the temporary level of TARGET_EXPRs. */
3833 target_temp_slot_level = thisblock->data.block.block_target_temp_slot_level;
3835 /* Restore block_stack level for containing block. */
3837 stack_block_stack = thisblock->data.block.innermost_stack_block;
3838 POPSTACK (block_stack);
3840 /* Pop the stack slot nesting and free any slots at this level. */
3844 /* Generate code to save the stack pointer at the start of the current block
3845 and set up to restore it on exit. */
3848 save_stack_pointer (void)
3850 struct nesting *thisblock = block_stack;
3852 if (thisblock->data.block.stack_level == 0)
3854 emit_stack_save (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3855 &thisblock->data.block.stack_level,
3856 thisblock->data.block.first_insn);
3857 stack_block_stack = thisblock;
3861 /* Generate RTL for the automatic variable declaration DECL.
3862 (Other kinds of declarations are simply ignored if seen here.) */
3865 expand_decl (tree decl)
3869 type = TREE_TYPE (decl);
3871 /* For a CONST_DECL, set mode, alignment, and sizes from those of the
3872 type in case this node is used in a reference. */
3873 if (TREE_CODE (decl) == CONST_DECL)
3875 DECL_MODE (decl) = TYPE_MODE (type);
3876 DECL_ALIGN (decl) = TYPE_ALIGN (type);
3877 DECL_SIZE (decl) = TYPE_SIZE (type);
3878 DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (type);
3882 /* Otherwise, only automatic variables need any expansion done. Static and
3883 external variables, and external functions, will be handled by
3884 `assemble_variable' (called from finish_decl). TYPE_DECL requires
3885 nothing. PARM_DECLs are handled in `assign_parms'. */
3886 if (TREE_CODE (decl) != VAR_DECL)
3889 if (TREE_STATIC (decl) || DECL_EXTERNAL (decl))
3892 /* Create the RTL representation for the variable. */
3894 if (type == error_mark_node)
3895 SET_DECL_RTL (decl, gen_rtx_MEM (BLKmode, const0_rtx));
3897 else if (DECL_SIZE (decl) == 0)
3898 /* Variable with incomplete type. */
3901 if (DECL_INITIAL (decl) == 0)
3902 /* Error message was already done; now avoid a crash. */
3903 x = gen_rtx_MEM (BLKmode, const0_rtx);
3905 /* An initializer is going to decide the size of this array.
3906 Until we know the size, represent its address with a reg. */
3907 x = gen_rtx_MEM (BLKmode, gen_reg_rtx (Pmode));
3909 set_mem_attributes (x, decl, 1);
3910 SET_DECL_RTL (decl, x);
3912 else if (DECL_MODE (decl) != BLKmode
3913 /* If -ffloat-store, don't put explicit float vars
3915 && !(flag_float_store
3916 && TREE_CODE (type) == REAL_TYPE)
3917 && ! TREE_THIS_VOLATILE (decl)
3918 && ! DECL_NONLOCAL (decl)
3919 && (DECL_REGISTER (decl) || DECL_ARTIFICIAL (decl) || optimize))
3921 /* Automatic variable that can go in a register. */
3922 int unsignedp = TREE_UNSIGNED (type);
3923 enum machine_mode reg_mode
3924 = promote_mode (type, DECL_MODE (decl), &unsignedp, 0);
3926 SET_DECL_RTL (decl, gen_reg_rtx (reg_mode));
3928 if (!DECL_ARTIFICIAL (decl))
3929 mark_user_reg (DECL_RTL (decl));
3931 if (POINTER_TYPE_P (type))
3932 mark_reg_pointer (DECL_RTL (decl),
3933 TYPE_ALIGN (TREE_TYPE (TREE_TYPE (decl))));
3935 maybe_set_unchanging (DECL_RTL (decl), decl);
3937 /* If something wants our address, try to use ADDRESSOF. */
3938 if (TREE_ADDRESSABLE (decl))
3939 put_var_into_stack (decl, /*rescan=*/false);
3942 else if (TREE_CODE (DECL_SIZE_UNIT (decl)) == INTEGER_CST
3943 && ! (flag_stack_check && ! STACK_CHECK_BUILTIN
3944 && 0 < compare_tree_int (DECL_SIZE_UNIT (decl),
3945 STACK_CHECK_MAX_VAR_SIZE)))
3947 /* Variable of fixed size that goes on the stack. */
3952 /* If we previously made RTL for this decl, it must be an array
3953 whose size was determined by the initializer.
3954 The old address was a register; set that register now
3955 to the proper address. */
3956 if (DECL_RTL_SET_P (decl))
3958 if (GET_CODE (DECL_RTL (decl)) != MEM
3959 || GET_CODE (XEXP (DECL_RTL (decl), 0)) != REG)
3961 oldaddr = XEXP (DECL_RTL (decl), 0);
3964 /* Set alignment we actually gave this decl. */
3965 DECL_ALIGN (decl) = (DECL_MODE (decl) == BLKmode ? BIGGEST_ALIGNMENT
3966 : GET_MODE_BITSIZE (DECL_MODE (decl)));
3967 DECL_USER_ALIGN (decl) = 0;
3969 x = assign_temp (decl, 1, 1, 1);
3970 set_mem_attributes (x, decl, 1);
3971 SET_DECL_RTL (decl, x);
3975 addr = force_operand (XEXP (DECL_RTL (decl), 0), oldaddr);
3976 if (addr != oldaddr)
3977 emit_move_insn (oldaddr, addr);
3981 /* Dynamic-size object: must push space on the stack. */
3983 rtx address, size, x;
3985 /* Record the stack pointer on entry to block, if have
3986 not already done so. */
3987 do_pending_stack_adjust ();
3988 save_stack_pointer ();
3990 /* In function-at-a-time mode, variable_size doesn't expand this,
3992 if (TREE_CODE (type) == ARRAY_TYPE && TYPE_DOMAIN (type))
3993 expand_expr (TYPE_MAX_VALUE (TYPE_DOMAIN (type)),
3994 const0_rtx, VOIDmode, 0);
3996 /* Compute the variable's size, in bytes. */
3997 size = expand_expr (DECL_SIZE_UNIT (decl), NULL_RTX, VOIDmode, 0);
4000 /* Allocate space on the stack for the variable. Note that
4001 DECL_ALIGN says how the variable is to be aligned and we
4002 cannot use it to conclude anything about the alignment of
4004 address = allocate_dynamic_stack_space (size, NULL_RTX,
4005 TYPE_ALIGN (TREE_TYPE (decl)));
4007 /* Reference the variable indirect through that rtx. */
4008 x = gen_rtx_MEM (DECL_MODE (decl), address);
4009 set_mem_attributes (x, decl, 1);
4010 SET_DECL_RTL (decl, x);
4013 /* Indicate the alignment we actually gave this variable. */
4014 #ifdef STACK_BOUNDARY
4015 DECL_ALIGN (decl) = STACK_BOUNDARY;
4017 DECL_ALIGN (decl) = BIGGEST_ALIGNMENT;
4019 DECL_USER_ALIGN (decl) = 0;
4023 /* Emit code to perform the initialization of a declaration DECL. */
4026 expand_decl_init (tree decl)
4028 int was_used = TREE_USED (decl);
4030 /* If this is a CONST_DECL, we don't have to generate any code. Likewise
4031 for static decls. */
4032 if (TREE_CODE (decl) == CONST_DECL
4033 || TREE_STATIC (decl))
4036 /* Compute and store the initial value now. */
4040 if (DECL_INITIAL (decl) == error_mark_node)
4042 enum tree_code code = TREE_CODE (TREE_TYPE (decl));
4044 if (code == INTEGER_TYPE || code == REAL_TYPE || code == ENUMERAL_TYPE
4045 || code == POINTER_TYPE || code == REFERENCE_TYPE)
4046 expand_assignment (decl, convert (TREE_TYPE (decl), integer_zero_node),
4050 else if (DECL_INITIAL (decl) && TREE_CODE (DECL_INITIAL (decl)) != TREE_LIST)
4052 emit_line_note (DECL_SOURCE_LOCATION (decl));
4053 expand_assignment (decl, DECL_INITIAL (decl), 0);
4057 /* Don't let the initialization count as "using" the variable. */
4058 TREE_USED (decl) = was_used;
4060 /* Free any temporaries we made while initializing the decl. */
4061 preserve_temp_slots (NULL_RTX);
4066 /* CLEANUP is an expression to be executed at exit from this binding contour;
4067 for example, in C++, it might call the destructor for this variable.
4069 We wrap CLEANUP in an UNSAVE_EXPR node, so that we can expand the
4070 CLEANUP multiple times, and have the correct semantics. This
4071 happens in exception handling, for gotos, returns, breaks that
4072 leave the current scope.
4074 If CLEANUP is nonzero and DECL is zero, we record a cleanup
4075 that is not associated with any particular variable. */
4078 expand_decl_cleanup (tree decl, tree cleanup)
4080 struct nesting *thisblock;
4082 /* Error if we are not in any block. */
4083 if (cfun == 0 || block_stack == 0)
4086 thisblock = block_stack;
4088 /* Record the cleanup if there is one. */
4094 tree *cleanups = &thisblock->data.block.cleanups;
4095 int cond_context = conditional_context ();
4099 rtx flag = gen_reg_rtx (word_mode);
4104 emit_move_insn (flag, const0_rtx);
4105 set_flag_0 = get_insns ();
4108 thisblock->data.block.last_unconditional_cleanup
4109 = emit_insn_after (set_flag_0,
4110 thisblock->data.block.last_unconditional_cleanup);
4112 emit_move_insn (flag, const1_rtx);
4114 cond = build_decl (VAR_DECL, NULL_TREE,
4115 (*lang_hooks.types.type_for_mode) (word_mode, 1));
4116 SET_DECL_RTL (cond, flag);
4118 /* Conditionalize the cleanup. */
4119 cleanup = build (COND_EXPR, void_type_node,
4120 (*lang_hooks.truthvalue_conversion) (cond),
4121 cleanup, integer_zero_node);
4122 cleanup = fold (cleanup);
4124 cleanups = &thisblock->data.block.cleanups;
4127 cleanup = unsave_expr (cleanup);
4129 t = *cleanups = tree_cons (decl, cleanup, *cleanups);
4132 /* If this block has a cleanup, it belongs in stack_block_stack. */
4133 stack_block_stack = thisblock;
4140 if (! using_eh_for_cleanups_p)
4141 TREE_ADDRESSABLE (t) = 1;
4143 expand_eh_region_start ();
4150 thisblock->data.block.last_unconditional_cleanup
4151 = emit_insn_after (seq,
4152 thisblock->data.block.last_unconditional_cleanup);
4156 thisblock->data.block.last_unconditional_cleanup
4158 /* When we insert instructions after the last unconditional cleanup,
4159 we don't adjust last_insn. That means that a later add_insn will
4160 clobber the instructions we've just added. The easiest way to
4161 fix this is to just insert another instruction here, so that the
4162 instructions inserted after the last unconditional cleanup are
4163 never the last instruction. */
4164 emit_note (NOTE_INSN_DELETED);
4170 /* Like expand_decl_cleanup, but maybe only run the cleanup if an exception
4174 expand_decl_cleanup_eh (tree decl, tree cleanup, int eh_only)
4176 int ret = expand_decl_cleanup (decl, cleanup);
4179 tree node = block_stack->data.block.cleanups;
4180 CLEANUP_EH_ONLY (node) = eh_only;
4185 /* DECL is an anonymous union. CLEANUP is a cleanup for DECL.
4186 DECL_ELTS is the list of elements that belong to DECL's type.
4187 In each, the TREE_VALUE is a VAR_DECL, and the TREE_PURPOSE a cleanup. */
4190 expand_anon_union_decl (tree decl, tree cleanup, tree decl_elts)
4192 struct nesting *thisblock = cfun == 0 ? 0 : block_stack;
4196 /* If any of the elements are addressable, so is the entire union. */
4197 for (t = decl_elts; t; t = TREE_CHAIN (t))
4198 if (TREE_ADDRESSABLE (TREE_VALUE (t)))
4200 TREE_ADDRESSABLE (decl) = 1;
4205 expand_decl_cleanup (decl, cleanup);
4206 x = DECL_RTL (decl);
4208 /* Go through the elements, assigning RTL to each. */
4209 for (t = decl_elts; t; t = TREE_CHAIN (t))
4211 tree decl_elt = TREE_VALUE (t);
4212 tree cleanup_elt = TREE_PURPOSE (t);
4213 enum machine_mode mode = TYPE_MODE (TREE_TYPE (decl_elt));
4215 /* If any of the elements are addressable, so is the entire
4217 if (TREE_USED (decl_elt))
4218 TREE_USED (decl) = 1;
4220 /* Propagate the union's alignment to the elements. */
4221 DECL_ALIGN (decl_elt) = DECL_ALIGN (decl);
4222 DECL_USER_ALIGN (decl_elt) = DECL_USER_ALIGN (decl);
4224 /* If the element has BLKmode and the union doesn't, the union is
4225 aligned such that the element doesn't need to have BLKmode, so
4226 change the element's mode to the appropriate one for its size. */
4227 if (mode == BLKmode && DECL_MODE (decl) != BLKmode)
4228 DECL_MODE (decl_elt) = mode
4229 = mode_for_size_tree (DECL_SIZE (decl_elt), MODE_INT, 1);
4231 /* (SUBREG (MEM ...)) at RTL generation time is invalid, so we
4232 instead create a new MEM rtx with the proper mode. */
4233 if (GET_CODE (x) == MEM)
4235 if (mode == GET_MODE (x))
4236 SET_DECL_RTL (decl_elt, x);
4238 SET_DECL_RTL (decl_elt, adjust_address_nv (x, mode, 0));
4240 else if (GET_CODE (x) == REG)
4242 if (mode == GET_MODE (x))
4243 SET_DECL_RTL (decl_elt, x);
4245 SET_DECL_RTL (decl_elt, gen_lowpart_SUBREG (mode, x));
4250 /* Record the cleanup if there is one. */
4253 thisblock->data.block.cleanups
4254 = tree_cons (decl_elt, cleanup_elt,
4255 thisblock->data.block.cleanups);
4259 /* Expand a list of cleanups LIST.
4260 Elements may be expressions or may be nested lists.
4262 If IN_FIXUP is nonzero, we are generating this cleanup for a fixup
4263 goto and handle protection regions specially in that case.
4265 If REACHABLE, we emit code, otherwise just inform the exception handling
4266 code about this finalization. */
4269 expand_cleanups (tree list, int in_fixup, int reachable)
4272 for (tail = list; tail; tail = TREE_CHAIN (tail))
4273 if (TREE_CODE (TREE_VALUE (tail)) == TREE_LIST)
4274 expand_cleanups (TREE_VALUE (tail), in_fixup, reachable);
4277 if (! in_fixup && using_eh_for_cleanups_p)
4278 expand_eh_region_end_cleanup (TREE_VALUE (tail));
4280 if (reachable && !CLEANUP_EH_ONLY (tail))
4282 /* Cleanups may be run multiple times. For example,
4283 when exiting a binding contour, we expand the
4284 cleanups associated with that contour. When a goto
4285 within that binding contour has a target outside that
4286 contour, it will expand all cleanups from its scope to
4287 the target. Though the cleanups are expanded multiple
4288 times, the control paths are non-overlapping so the
4289 cleanups will not be executed twice. */
4291 /* We may need to protect from outer cleanups. */
4292 if (in_fixup && using_eh_for_cleanups_p)
4294 expand_eh_region_start ();
4296 expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0);
4298 expand_eh_region_end_fixup (TREE_VALUE (tail));
4301 expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0);
4308 /* Mark when the context we are emitting RTL for as a conditional
4309 context, so that any cleanup actions we register with
4310 expand_decl_init will be properly conditionalized when those
4311 cleanup actions are later performed. Must be called before any
4312 expression (tree) is expanded that is within a conditional context. */
4315 start_cleanup_deferral (void)
4317 /* block_stack can be NULL if we are inside the parameter list. It is
4318 OK to do nothing, because cleanups aren't possible here. */
4320 ++block_stack->data.block.conditional_code;
4323 /* Mark the end of a conditional region of code. Because cleanup
4324 deferrals may be nested, we may still be in a conditional region
4325 after we end the currently deferred cleanups, only after we end all
4326 deferred cleanups, are we back in unconditional code. */
4329 end_cleanup_deferral (void)
4331 /* block_stack can be NULL if we are inside the parameter list. It is
4332 OK to do nothing, because cleanups aren't possible here. */
4334 --block_stack->data.block.conditional_code;
4338 last_cleanup_this_contour (void)
4340 if (block_stack == 0)
4343 return block_stack->data.block.cleanups;
4346 /* Return 1 if there are any pending cleanups at this point.
4347 Check the current contour as well as contours that enclose
4348 the current contour. */
4351 any_pending_cleanups (void)
4353 struct nesting *block;
4355 if (cfun == NULL || cfun->stmt == NULL || block_stack == 0)
4358 if (block_stack->data.block.cleanups != NULL)
4361 if (block_stack->data.block.outer_cleanups == 0)
4364 for (block = block_stack->next; block; block = block->next)
4365 if (block->data.block.cleanups != 0)
4371 /* Enter a case (Pascal) or switch (C) statement.
4372 Push a block onto case_stack and nesting_stack
4373 to accumulate the case-labels that are seen
4374 and to record the labels generated for the statement.
4376 EXIT_FLAG is nonzero if `exit_something' should exit this case stmt.
4377 Otherwise, this construct is transparent for `exit_something'.
4379 EXPR is the index-expression to be dispatched on.
4380 TYPE is its nominal type. We could simply convert EXPR to this type,
4381 but instead we take short cuts. */
4384 expand_start_case (int exit_flag, tree expr, tree type,
4385 const char *printname)
4387 struct nesting *thiscase = ALLOC_NESTING ();
4389 /* Make an entry on case_stack for the case we are entering. */
4391 thiscase->desc = CASE_NESTING;
4392 thiscase->next = case_stack;
4393 thiscase->all = nesting_stack;
4394 thiscase->depth = ++nesting_depth;
4395 thiscase->exit_label = exit_flag ? gen_label_rtx () : 0;
4396 thiscase->data.case_stmt.case_list = 0;
4397 thiscase->data.case_stmt.index_expr = expr;
4398 thiscase->data.case_stmt.nominal_type = type;
4399 thiscase->data.case_stmt.default_label = 0;
4400 thiscase->data.case_stmt.printname = printname;
4401 thiscase->data.case_stmt.line_number_status = force_line_numbers ();
4402 case_stack = thiscase;
4403 nesting_stack = thiscase;
4405 do_pending_stack_adjust ();
4408 /* Make sure case_stmt.start points to something that won't
4409 need any transformation before expand_end_case. */
4410 if (GET_CODE (get_last_insn ()) != NOTE)
4411 emit_note (NOTE_INSN_DELETED);
4413 thiscase->data.case_stmt.start = get_last_insn ();
4415 start_cleanup_deferral ();
4418 /* Start a "dummy case statement" within which case labels are invalid
4419 and are not connected to any larger real case statement.
4420 This can be used if you don't want to let a case statement jump
4421 into the middle of certain kinds of constructs. */
4424 expand_start_case_dummy (void)
4426 struct nesting *thiscase = ALLOC_NESTING ();
4428 /* Make an entry on case_stack for the dummy. */
4430 thiscase->desc = CASE_NESTING;
4431 thiscase->next = case_stack;
4432 thiscase->all = nesting_stack;
4433 thiscase->depth = ++nesting_depth;
4434 thiscase->exit_label = 0;
4435 thiscase->data.case_stmt.case_list = 0;
4436 thiscase->data.case_stmt.start = 0;
4437 thiscase->data.case_stmt.nominal_type = 0;
4438 thiscase->data.case_stmt.default_label = 0;
4439 case_stack = thiscase;
4440 nesting_stack = thiscase;
4441 start_cleanup_deferral ();
4445 check_seenlabel (void)
4447 /* If this is the first label, warn if any insns have been emitted. */
4448 if (case_stack->data.case_stmt.line_number_status >= 0)
4452 restore_line_number_status
4453 (case_stack->data.case_stmt.line_number_status);
4454 case_stack->data.case_stmt.line_number_status = -1;
4456 for (insn = case_stack->data.case_stmt.start;
4458 insn = NEXT_INSN (insn))
4460 if (GET_CODE (insn) == CODE_LABEL)
4462 if (GET_CODE (insn) != NOTE
4463 && (GET_CODE (insn) != INSN || GET_CODE (PATTERN (insn)) != USE))
4466 insn = PREV_INSN (insn);
4467 while (insn && (GET_CODE (insn) != NOTE || NOTE_LINE_NUMBER (insn) < 0));
4469 /* If insn is zero, then there must have been a syntax error. */
4473 locus.file = NOTE_SOURCE_FILE (insn);
4474 locus.line = NOTE_LINE_NUMBER (insn);
4475 warning ("%Hunreachable code at beginning of %s", &locus,
4476 case_stack->data.case_stmt.printname);
4484 /* Accumulate one case or default label inside a case or switch statement.
4485 VALUE is the value of the case (a null pointer, for a default label).
4486 The function CONVERTER, when applied to arguments T and V,
4487 converts the value V to the type T.
4489 If not currently inside a case or switch statement, return 1 and do
4490 nothing. The caller will print a language-specific error message.
4491 If VALUE is a duplicate or overlaps, return 2 and do nothing
4492 except store the (first) duplicate node in *DUPLICATE.
4493 If VALUE is out of range, return 3 and do nothing.
4494 If we are jumping into the scope of a cleanup or var-sized array, return 5.
4495 Return 0 on success.
4497 Extended to handle range statements. */
4500 pushcase (tree value, tree (*converter) (tree, tree), tree label,
4506 /* Fail if not inside a real case statement. */
4507 if (! (case_stack && case_stack->data.case_stmt.start))
4510 if (stack_block_stack
4511 && stack_block_stack->depth > case_stack->depth)
4514 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
4515 nominal_type = case_stack->data.case_stmt.nominal_type;
4517 /* If the index is erroneous, avoid more problems: pretend to succeed. */
4518 if (index_type == error_mark_node)
4521 /* Convert VALUE to the type in which the comparisons are nominally done. */
4523 value = (*converter) (nominal_type, value);
4527 /* Fail if this value is out of range for the actual type of the index
4528 (which may be narrower than NOMINAL_TYPE). */
4530 && (TREE_CONSTANT_OVERFLOW (value)
4531 || ! int_fits_type_p (value, index_type)))
4534 return add_case_node (value, value, label, duplicate);
4537 /* Like pushcase but this case applies to all values between VALUE1 and
4538 VALUE2 (inclusive). If VALUE1 is NULL, the range starts at the lowest
4539 value of the index type and ends at VALUE2. If VALUE2 is NULL, the range
4540 starts at VALUE1 and ends at the highest value of the index type.
4541 If both are NULL, this case applies to all values.
4543 The return value is the same as that of pushcase but there is one
4544 additional error code: 4 means the specified range was empty. */
4547 pushcase_range (tree value1, tree value2, tree (*converter) (tree, tree),
4548 tree label, tree *duplicate)
4553 /* Fail if not inside a real case statement. */
4554 if (! (case_stack && case_stack->data.case_stmt.start))
4557 if (stack_block_stack
4558 && stack_block_stack->depth > case_stack->depth)
4561 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
4562 nominal_type = case_stack->data.case_stmt.nominal_type;
4564 /* If the index is erroneous, avoid more problems: pretend to succeed. */
4565 if (index_type == error_mark_node)
4570 /* Convert VALUEs to type in which the comparisons are nominally done
4571 and replace any unspecified value with the corresponding bound. */
4573 value1 = TYPE_MIN_VALUE (index_type);
4575 value2 = TYPE_MAX_VALUE (index_type);
4577 /* Fail if the range is empty. Do this before any conversion since
4578 we want to allow out-of-range empty ranges. */
4579 if (value2 != 0 && tree_int_cst_lt (value2, value1))
4582 /* If the max was unbounded, use the max of the nominal_type we are
4583 converting to. Do this after the < check above to suppress false
4586 value2 = TYPE_MAX_VALUE (nominal_type);
4588 value1 = (*converter) (nominal_type, value1);
4589 value2 = (*converter) (nominal_type, value2);
4591 /* Fail if these values are out of range. */
4592 if (TREE_CONSTANT_OVERFLOW (value1)
4593 || ! int_fits_type_p (value1, index_type))
4596 if (TREE_CONSTANT_OVERFLOW (value2)
4597 || ! int_fits_type_p (value2, index_type))
4600 return add_case_node (value1, value2, label, duplicate);
4603 /* Do the actual insertion of a case label for pushcase and pushcase_range
4604 into case_stack->data.case_stmt.case_list. Use an AVL tree to avoid
4605 slowdown for large switch statements. */
4608 add_case_node (tree low, tree high, tree label, tree *duplicate)
4610 struct case_node *p, **q, *r;
4612 /* If there's no HIGH value, then this is not a case range; it's
4613 just a simple case label. But that's just a degenerate case
4618 /* Handle default labels specially. */
4621 if (case_stack->data.case_stmt.default_label != 0)
4623 *duplicate = case_stack->data.case_stmt.default_label;
4626 case_stack->data.case_stmt.default_label = label;
4627 expand_label (label);
4631 q = &case_stack->data.case_stmt.case_list;
4638 /* Keep going past elements distinctly greater than HIGH. */
4639 if (tree_int_cst_lt (high, p->low))
4642 /* or distinctly less than LOW. */
4643 else if (tree_int_cst_lt (p->high, low))
4648 /* We have an overlap; this is an error. */
4649 *duplicate = p->code_label;
4654 /* Add this label to the chain, and succeed. */
4656 r = ggc_alloc (sizeof (struct case_node));
4659 /* If the bounds are equal, turn this into the one-value case. */
4660 if (tree_int_cst_equal (low, high))
4665 r->code_label = label;
4666 expand_label (label);
4676 struct case_node *s;
4682 if (! (b = p->balance))
4683 /* Growth propagation from left side. */
4690 if ((p->left = s = r->right))
4699 if ((r->parent = s))
4707 case_stack->data.case_stmt.case_list = r;
4710 /* r->balance == +1 */
4715 struct case_node *t = r->right;
4717 if ((p->left = s = t->right))
4721 if ((r->right = s = t->left))
4735 if ((t->parent = s))
4743 case_stack->data.case_stmt.case_list = t;
4750 /* p->balance == +1; growth of left side balances the node. */
4760 if (! (b = p->balance))
4761 /* Growth propagation from right side. */
4769 if ((p->right = s = r->left))
4777 if ((r->parent = s))
4786 case_stack->data.case_stmt.case_list = r;
4790 /* r->balance == -1 */
4794 struct case_node *t = r->left;
4796 if ((p->right = s = t->left))
4801 if ((r->left = s = t->right))
4815 if ((t->parent = s))
4824 case_stack->data.case_stmt.case_list = t;
4830 /* p->balance == -1; growth of right side balances the node. */
4843 /* Returns the number of possible values of TYPE.
4844 Returns -1 if the number is unknown, variable, or if the number does not
4845 fit in a HOST_WIDE_INT.
4846 Sets *SPARSENESS to 2 if TYPE is an ENUMERAL_TYPE whose values
4847 do not increase monotonically (there may be duplicates);
4848 to 1 if the values increase monotonically, but not always by 1;
4849 otherwise sets it to 0. */
4852 all_cases_count (tree type, int *sparseness)
4855 HOST_WIDE_INT count, minval, lastval;
4859 switch (TREE_CODE (type))
4866 count = 1 << BITS_PER_UNIT;
4871 if (TYPE_MAX_VALUE (type) != 0
4872 && 0 != (t = fold (build (MINUS_EXPR, type, TYPE_MAX_VALUE (type),
4873 TYPE_MIN_VALUE (type))))
4874 && 0 != (t = fold (build (PLUS_EXPR, type, t,
4875 convert (type, integer_zero_node))))
4876 && host_integerp (t, 1))
4877 count = tree_low_cst (t, 1);
4883 /* Don't waste time with enumeral types with huge values. */
4884 if (! host_integerp (TYPE_MIN_VALUE (type), 0)
4885 || TYPE_MAX_VALUE (type) == 0
4886 || ! host_integerp (TYPE_MAX_VALUE (type), 0))
4889 lastval = minval = tree_low_cst (TYPE_MIN_VALUE (type), 0);
4892 for (t = TYPE_VALUES (type); t != NULL_TREE; t = TREE_CHAIN (t))
4894 HOST_WIDE_INT thisval = tree_low_cst (TREE_VALUE (t), 0);
4896 if (*sparseness == 2 || thisval <= lastval)
4898 else if (thisval != minval + count)
4909 #define BITARRAY_TEST(ARRAY, INDEX) \
4910 ((ARRAY)[(unsigned) (INDEX) / HOST_BITS_PER_CHAR]\
4911 & (1 << ((unsigned) (INDEX) % HOST_BITS_PER_CHAR)))
4912 #define BITARRAY_SET(ARRAY, INDEX) \
4913 ((ARRAY)[(unsigned) (INDEX) / HOST_BITS_PER_CHAR]\
4914 |= 1 << ((unsigned) (INDEX) % HOST_BITS_PER_CHAR))
4916 /* Set the elements of the bitstring CASES_SEEN (which has length COUNT),
4917 with the case values we have seen, assuming the case expression
4919 SPARSENESS is as determined by all_cases_count.
4921 The time needed is proportional to COUNT, unless
4922 SPARSENESS is 2, in which case quadratic time is needed. */
4925 mark_seen_cases (tree type, unsigned char *cases_seen, HOST_WIDE_INT count,
4928 tree next_node_to_try = NULL_TREE;
4929 HOST_WIDE_INT next_node_offset = 0;
4931 struct case_node *n, *root = case_stack->data.case_stmt.case_list;
4932 tree val = make_node (INTEGER_CST);
4934 TREE_TYPE (val) = type;
4938 else if (sparseness == 2)
4941 unsigned HOST_WIDE_INT xlo;
4943 /* This less efficient loop is only needed to handle
4944 duplicate case values (multiple enum constants
4945 with the same value). */
4946 TREE_TYPE (val) = TREE_TYPE (root->low);
4947 for (t = TYPE_VALUES (type), xlo = 0; t != NULL_TREE;
4948 t = TREE_CHAIN (t), xlo++)
4950 TREE_INT_CST_LOW (val) = TREE_INT_CST_LOW (TREE_VALUE (t));
4951 TREE_INT_CST_HIGH (val) = TREE_INT_CST_HIGH (TREE_VALUE (t));
4955 /* Keep going past elements distinctly greater than VAL. */
4956 if (tree_int_cst_lt (val, n->low))
4959 /* or distinctly less than VAL. */
4960 else if (tree_int_cst_lt (n->high, val))
4965 /* We have found a matching range. */
4966 BITARRAY_SET (cases_seen, xlo);
4976 case_stack->data.case_stmt.case_list = root = case_tree2list (root, 0);
4978 for (n = root; n; n = n->right)
4980 TREE_INT_CST_LOW (val) = TREE_INT_CST_LOW (n->low);
4981 TREE_INT_CST_HIGH (val) = TREE_INT_CST_HIGH (n->low);
4982 while (! tree_int_cst_lt (n->high, val))
4984 /* Calculate (into xlo) the "offset" of the integer (val).
4985 The element with lowest value has offset 0, the next smallest
4986 element has offset 1, etc. */
4988 unsigned HOST_WIDE_INT xlo;
4992 if (sparseness && TYPE_VALUES (type) != NULL_TREE)
4994 /* The TYPE_VALUES will be in increasing order, so
4995 starting searching where we last ended. */
4996 t = next_node_to_try;
4997 xlo = next_node_offset;
5003 t = TYPE_VALUES (type);
5006 if (tree_int_cst_equal (val, TREE_VALUE (t)))
5008 next_node_to_try = TREE_CHAIN (t);
5009 next_node_offset = xlo + 1;
5014 if (t == next_node_to_try)
5023 t = TYPE_MIN_VALUE (type);
5025 neg_double (TREE_INT_CST_LOW (t), TREE_INT_CST_HIGH (t),
5029 add_double (xlo, xhi,
5030 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val),
5034 if (xhi == 0 && xlo < (unsigned HOST_WIDE_INT) count)
5035 BITARRAY_SET (cases_seen, xlo);
5037 add_double (TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val),
5039 &TREE_INT_CST_LOW (val), &TREE_INT_CST_HIGH (val));
5045 /* Given a switch statement with an expression that is an enumeration
5046 type, warn if any of the enumeration type's literals are not
5047 covered by the case expressions of the switch. Also, warn if there
5048 are any extra switch cases that are *not* elements of the
5053 At one stage this function would: ``If all enumeration literals
5054 were covered by the case expressions, turn one of the expressions
5055 into the default expression since it should not be possible to fall
5056 through such a switch.''
5058 That code has since been removed as: ``This optimization is
5059 disabled because it causes valid programs to fail. ANSI C does not
5060 guarantee that an expression with enum type will have a value that
5061 is the same as one of the enumeration literals.'' */
5064 check_for_full_enumeration_handling (tree type)
5066 struct case_node *n;
5069 /* True iff the selector type is a numbered set mode. */
5072 /* The number of possible selector values. */
5075 /* For each possible selector value. a one iff it has been matched
5076 by a case value alternative. */
5077 unsigned char *cases_seen;
5079 /* The allocated size of cases_seen, in chars. */
5080 HOST_WIDE_INT bytes_needed;
5082 size = all_cases_count (type, &sparseness);
5083 bytes_needed = (size + HOST_BITS_PER_CHAR) / HOST_BITS_PER_CHAR;
5085 if (size > 0 && size < 600000
5086 /* We deliberately use calloc here, not cmalloc, so that we can suppress
5087 this optimization if we don't have enough memory rather than
5088 aborting, as xmalloc would do. */
5089 && (cases_seen = really_call_calloc (bytes_needed, 1)) != NULL)
5092 tree v = TYPE_VALUES (type);
5094 /* The time complexity of this code is normally O(N), where
5095 N being the number of members in the enumerated type.
5096 However, if type is an ENUMERAL_TYPE whose values do not
5097 increase monotonically, O(N*log(N)) time may be needed. */
5099 mark_seen_cases (type, cases_seen, size, sparseness);
5101 for (i = 0; v != NULL_TREE && i < size; i++, v = TREE_CHAIN (v))
5102 if (BITARRAY_TEST (cases_seen, i) == 0)
5103 warning ("enumeration value `%s' not handled in switch",
5104 IDENTIFIER_POINTER (TREE_PURPOSE (v)));
5109 /* Now we go the other way around; we warn if there are case
5110 expressions that don't correspond to enumerators. This can
5111 occur since C and C++ don't enforce type-checking of
5112 assignments to enumeration variables. */
5114 if (case_stack->data.case_stmt.case_list
5115 && case_stack->data.case_stmt.case_list->left)
5116 case_stack->data.case_stmt.case_list
5117 = case_tree2list (case_stack->data.case_stmt.case_list, 0);
5118 for (n = case_stack->data.case_stmt.case_list; n; n = n->right)
5120 for (chain = TYPE_VALUES (type);
5121 chain && !tree_int_cst_equal (n->low, TREE_VALUE (chain));
5122 chain = TREE_CHAIN (chain))
5127 if (TYPE_NAME (type) == 0)
5128 warning ("case value `%ld' not in enumerated type",
5129 (long) TREE_INT_CST_LOW (n->low));
5131 warning ("case value `%ld' not in enumerated type `%s'",
5132 (long) TREE_INT_CST_LOW (n->low),
5133 IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
5136 : DECL_NAME (TYPE_NAME (type))));
5138 if (!tree_int_cst_equal (n->low, n->high))
5140 for (chain = TYPE_VALUES (type);
5141 chain && !tree_int_cst_equal (n->high, TREE_VALUE (chain));
5142 chain = TREE_CHAIN (chain))
5147 if (TYPE_NAME (type) == 0)
5148 warning ("case value `%ld' not in enumerated type",
5149 (long) TREE_INT_CST_LOW (n->high));
5151 warning ("case value `%ld' not in enumerated type `%s'",
5152 (long) TREE_INT_CST_LOW (n->high),
5153 IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
5156 : DECL_NAME (TYPE_NAME (type))));
5163 /* Maximum number of case bit tests. */
5164 #define MAX_CASE_BIT_TESTS 3
5166 /* By default, enable case bit tests on targets with ashlsi3. */
5167 #ifndef CASE_USE_BIT_TESTS
5168 #define CASE_USE_BIT_TESTS (ashl_optab->handlers[word_mode].insn_code \
5169 != CODE_FOR_nothing)
5173 /* A case_bit_test represents a set of case nodes that may be
5174 selected from using a bit-wise comparison. HI and LO hold
5175 the integer to be tested against, LABEL contains the label
5176 to jump to upon success and BITS counts the number of case
5177 nodes handled by this test, typically the number of bits
5180 struct case_bit_test
5188 /* Determine whether "1 << x" is relatively cheap in word_mode. */
5191 bool lshift_cheap_p (void)
5193 static bool init = false;
5194 static bool cheap = true;
5198 rtx reg = gen_rtx_REG (word_mode, 10000);
5199 int cost = rtx_cost (gen_rtx_ASHIFT (word_mode, const1_rtx, reg), SET);
5200 cheap = cost < COSTS_N_INSNS (3);
5207 /* Comparison function for qsort to order bit tests by decreasing
5208 number of case nodes, i.e. the node with the most cases gets
5212 int case_bit_test_cmp (const void *p1, const void *p2)
5214 const struct case_bit_test *d1 = p1;
5215 const struct case_bit_test *d2 = p2;
5217 return d2->bits - d1->bits;
5220 /* Expand a switch statement by a short sequence of bit-wise
5221 comparisons. "switch(x)" is effectively converted into
5222 "if ((1 << (x-MINVAL)) & CST)" where CST and MINVAL are
5225 INDEX_EXPR is the value being switched on, which is of
5226 type INDEX_TYPE. MINVAL is the lowest case value of in
5227 the case nodes, of INDEX_TYPE type, and RANGE is highest
5228 value minus MINVAL, also of type INDEX_TYPE. NODES is
5229 the set of case nodes, and DEFAULT_LABEL is the label to
5230 branch to should none of the cases match.
5232 There *MUST* be MAX_CASE_BIT_TESTS or less unique case
5236 emit_case_bit_tests (tree index_type, tree index_expr, tree minval,
5237 tree range, case_node_ptr nodes, rtx default_label)
5239 struct case_bit_test test[MAX_CASE_BIT_TESTS];
5240 enum machine_mode mode;
5241 rtx expr, index, label;
5242 unsigned int i,j,lo,hi;
5243 struct case_node *n;
5247 for (n = nodes; n; n = n->right)
5249 label = label_rtx (n->code_label);
5250 for (i = 0; i < count; i++)
5251 if (same_case_target_p (label, test[i].label))
5256 if (count >= MAX_CASE_BIT_TESTS)
5260 test[i].label = label;
5267 lo = tree_low_cst (fold (build (MINUS_EXPR, index_type,
5268 n->low, minval)), 1);
5269 hi = tree_low_cst (fold (build (MINUS_EXPR, index_type,
5270 n->high, minval)), 1);
5271 for (j = lo; j <= hi; j++)
5272 if (j >= HOST_BITS_PER_WIDE_INT)
5273 test[i].hi |= (HOST_WIDE_INT) 1 << (j - HOST_BITS_PER_INT);
5275 test[i].lo |= (HOST_WIDE_INT) 1 << j;
5278 qsort (test, count, sizeof(*test), case_bit_test_cmp);
5280 index_expr = fold (build (MINUS_EXPR, index_type,
5281 convert (index_type, index_expr),
5282 convert (index_type, minval)));
5283 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
5285 index = protect_from_queue (index, 0);
5286 do_pending_stack_adjust ();
5288 mode = TYPE_MODE (index_type);
5289 expr = expand_expr (range, NULL_RTX, VOIDmode, 0);
5290 emit_cmp_and_jump_insns (index, expr, GTU, NULL_RTX, mode, 1,
5293 index = convert_to_mode (word_mode, index, 0);
5294 index = expand_binop (word_mode, ashl_optab, const1_rtx,
5295 index, NULL_RTX, 1, OPTAB_WIDEN);
5297 for (i = 0; i < count; i++)
5299 expr = immed_double_const (test[i].lo, test[i].hi, word_mode);
5300 expr = expand_binop (word_mode, and_optab, index, expr,
5301 NULL_RTX, 1, OPTAB_WIDEN);
5302 emit_cmp_and_jump_insns (expr, const0_rtx, NE, NULL_RTX,
5303 word_mode, 1, test[i].label);
5306 emit_jump (default_label);
5309 /* Terminate a case (Pascal) or switch (C) statement
5310 in which ORIG_INDEX is the expression to be tested.
5311 If ORIG_TYPE is not NULL, it is the original ORIG_INDEX
5312 type as given in the source before any compiler conversions.
5313 Generate the code to test it and jump to the right place. */
5316 expand_end_case_type (tree orig_index, tree orig_type)
5318 tree minval = NULL_TREE, maxval = NULL_TREE, range = NULL_TREE;
5319 rtx default_label = 0;
5320 struct case_node *n, *m;
5321 unsigned int count, uniq;
5327 rtx before_case, end, lab;
5328 struct nesting *thiscase = case_stack;
5329 tree index_expr, index_type;
5330 bool exit_done = false;
5333 /* Don't crash due to previous errors. */
5334 if (thiscase == NULL)
5337 index_expr = thiscase->data.case_stmt.index_expr;
5338 index_type = TREE_TYPE (index_expr);
5339 unsignedp = TREE_UNSIGNED (index_type);
5340 if (orig_type == NULL)
5341 orig_type = TREE_TYPE (orig_index);
5343 do_pending_stack_adjust ();
5345 /* This might get a spurious warning in the presence of a syntax error;
5346 it could be fixed by moving the call to check_seenlabel after the
5347 check for error_mark_node, and copying the code of check_seenlabel that
5348 deals with case_stack->data.case_stmt.line_number_status /
5349 restore_line_number_status in front of the call to end_cleanup_deferral;
5350 However, this might miss some useful warnings in the presence of
5351 non-syntax errors. */
5354 /* An ERROR_MARK occurs for various reasons including invalid data type. */
5355 if (index_type != error_mark_node)
5357 /* If the switch expression was an enumerated type, check that
5358 exactly all enumeration literals are covered by the cases.
5359 The check is made when -Wswitch was specified and there is no
5360 default case, or when -Wswitch-enum was specified. */
5361 if (((warn_switch && !thiscase->data.case_stmt.default_label)
5362 || warn_switch_enum)
5363 && TREE_CODE (orig_type) == ENUMERAL_TYPE
5364 && TREE_CODE (index_expr) != INTEGER_CST)
5365 check_for_full_enumeration_handling (orig_type);
5367 if (warn_switch_default && !thiscase->data.case_stmt.default_label)
5368 warning ("switch missing default case");
5370 /* If we don't have a default-label, create one here,
5371 after the body of the switch. */
5372 if (thiscase->data.case_stmt.default_label == 0)
5374 thiscase->data.case_stmt.default_label
5375 = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
5376 /* Share the exit label if possible. */
5377 if (thiscase->exit_label)
5379 SET_DECL_RTL (thiscase->data.case_stmt.default_label,
5380 thiscase->exit_label);
5383 expand_label (thiscase->data.case_stmt.default_label);
5385 default_label = label_rtx (thiscase->data.case_stmt.default_label);
5387 before_case = get_last_insn ();
5389 if (thiscase->data.case_stmt.case_list
5390 && thiscase->data.case_stmt.case_list->left)
5391 thiscase->data.case_stmt.case_list
5392 = case_tree2list (thiscase->data.case_stmt.case_list, 0);
5394 /* Simplify the case-list before we count it. */
5395 group_case_nodes (thiscase->data.case_stmt.case_list);
5396 strip_default_case_nodes (&thiscase->data.case_stmt.case_list,
5399 /* Get upper and lower bounds of case values.
5400 Also convert all the case values to the index expr's data type. */
5404 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5406 /* Check low and high label values are integers. */
5407 if (TREE_CODE (n->low) != INTEGER_CST)
5409 if (TREE_CODE (n->high) != INTEGER_CST)
5412 n->low = convert (index_type, n->low);
5413 n->high = convert (index_type, n->high);
5415 /* Count the elements and track the largest and smallest
5416 of them (treating them as signed even if they are not). */
5424 if (INT_CST_LT (n->low, minval))
5426 if (INT_CST_LT (maxval, n->high))
5429 /* A range counts double, since it requires two compares. */
5430 if (! tree_int_cst_equal (n->low, n->high))
5433 /* Count the number of unique case node targets. */
5435 lab = label_rtx (n->code_label);
5436 for (m = thiscase->data.case_stmt.case_list; m != n; m = m->right)
5437 if (same_case_target_p (label_rtx (m->code_label), lab))
5444 /* Compute span of values. */
5446 range = fold (build (MINUS_EXPR, index_type, maxval, minval));
5448 end_cleanup_deferral ();
5452 expand_expr (index_expr, const0_rtx, VOIDmode, 0);
5454 emit_jump (default_label);
5457 /* Try implementing this switch statement by a short sequence of
5458 bit-wise comparisons. However, we let the binary-tree case
5459 below handle constant index expressions. */
5460 else if (CASE_USE_BIT_TESTS
5461 && ! TREE_CONSTANT (index_expr)
5462 && compare_tree_int (range, GET_MODE_BITSIZE (word_mode)) < 0
5463 && compare_tree_int (range, 0) > 0
5464 && lshift_cheap_p ()
5465 && ((uniq == 1 && count >= 3)
5466 || (uniq == 2 && count >= 5)
5467 || (uniq == 3 && count >= 6)))
5469 /* Optimize the case where all the case values fit in a
5470 word without having to subtract MINVAL. In this case,
5471 we can optimize away the subtraction. */
5472 if (compare_tree_int (minval, 0) > 0
5473 && compare_tree_int (maxval, GET_MODE_BITSIZE (word_mode)) < 0)
5475 minval = integer_zero_node;
5478 emit_case_bit_tests (index_type, index_expr, minval, range,
5479 thiscase->data.case_stmt.case_list,
5483 /* If range of values is much bigger than number of values,
5484 make a sequence of conditional branches instead of a dispatch.
5485 If the switch-index is a constant, do it this way
5486 because we can optimize it. */
5488 else if (count < case_values_threshold ()
5489 || compare_tree_int (range,
5490 (optimize_size ? 3 : 10) * count) > 0
5491 /* RANGE may be signed, and really large ranges will show up
5492 as negative numbers. */
5493 || compare_tree_int (range, 0) < 0
5494 #ifndef ASM_OUTPUT_ADDR_DIFF_ELT
5497 || TREE_CONSTANT (index_expr))
5499 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
5501 /* If the index is a short or char that we do not have
5502 an insn to handle comparisons directly, convert it to
5503 a full integer now, rather than letting each comparison
5504 generate the conversion. */
5506 if (GET_MODE_CLASS (GET_MODE (index)) == MODE_INT
5507 && ! have_insn_for (COMPARE, GET_MODE (index)))
5509 enum machine_mode wider_mode;
5510 for (wider_mode = GET_MODE (index); wider_mode != VOIDmode;
5511 wider_mode = GET_MODE_WIDER_MODE (wider_mode))
5512 if (have_insn_for (COMPARE, wider_mode))
5514 index = convert_to_mode (wider_mode, index, unsignedp);
5520 do_pending_stack_adjust ();
5522 index = protect_from_queue (index, 0);
5523 if (GET_CODE (index) == MEM)
5524 index = copy_to_reg (index);
5525 if (GET_CODE (index) == CONST_INT
5526 || TREE_CODE (index_expr) == INTEGER_CST)
5528 /* Make a tree node with the proper constant value
5529 if we don't already have one. */
5530 if (TREE_CODE (index_expr) != INTEGER_CST)
5533 = build_int_2 (INTVAL (index),
5534 unsignedp || INTVAL (index) >= 0 ? 0 : -1);
5535 index_expr = convert (index_type, index_expr);
5538 /* For constant index expressions we need only
5539 issue an unconditional branch to the appropriate
5540 target code. The job of removing any unreachable
5541 code is left to the optimization phase if the
5542 "-O" option is specified. */
5543 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5544 if (! tree_int_cst_lt (index_expr, n->low)
5545 && ! tree_int_cst_lt (n->high, index_expr))
5549 emit_jump (label_rtx (n->code_label));
5551 emit_jump (default_label);
5555 /* If the index expression is not constant we generate
5556 a binary decision tree to select the appropriate
5557 target code. This is done as follows:
5559 The list of cases is rearranged into a binary tree,
5560 nearly optimal assuming equal probability for each case.
5562 The tree is transformed into RTL, eliminating
5563 redundant test conditions at the same time.
5565 If program flow could reach the end of the
5566 decision tree an unconditional jump to the
5567 default code is emitted. */
5570 = (TREE_CODE (orig_type) != ENUMERAL_TYPE
5571 && estimate_case_costs (thiscase->data.case_stmt.case_list));
5572 balance_case_nodes (&thiscase->data.case_stmt.case_list, NULL);
5573 emit_case_nodes (index, thiscase->data.case_stmt.case_list,
5574 default_label, index_type);
5575 emit_jump_if_reachable (default_label);
5580 table_label = gen_label_rtx ();
5581 if (! try_casesi (index_type, index_expr, minval, range,
5582 table_label, default_label))
5584 index_type = thiscase->data.case_stmt.nominal_type;
5586 /* Index jumptables from zero for suitable values of
5587 minval to avoid a subtraction. */
5589 && compare_tree_int (minval, 0) > 0
5590 && compare_tree_int (minval, 3) < 0)
5592 minval = integer_zero_node;
5596 if (! try_tablejump (index_type, index_expr, minval, range,
5597 table_label, default_label))
5601 /* Get table of labels to jump to, in order of case index. */
5603 ncases = tree_low_cst (range, 0) + 1;
5604 labelvec = alloca (ncases * sizeof (rtx));
5605 memset (labelvec, 0, ncases * sizeof (rtx));
5607 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5609 /* Compute the low and high bounds relative to the minimum
5610 value since that should fit in a HOST_WIDE_INT while the
5611 actual values may not. */
5613 = tree_low_cst (fold (build (MINUS_EXPR, index_type,
5614 n->low, minval)), 1);
5615 HOST_WIDE_INT i_high
5616 = tree_low_cst (fold (build (MINUS_EXPR, index_type,
5617 n->high, minval)), 1);
5620 for (i = i_low; i <= i_high; i ++)
5622 = gen_rtx_LABEL_REF (Pmode, label_rtx (n->code_label));
5625 /* Fill in the gaps with the default. */
5626 for (i = 0; i < ncases; i++)
5627 if (labelvec[i] == 0)
5628 labelvec[i] = gen_rtx_LABEL_REF (Pmode, default_label);
5630 /* Output the table. */
5631 emit_label (table_label);
5633 if (CASE_VECTOR_PC_RELATIVE || flag_pic)
5634 emit_jump_insn (gen_rtx_ADDR_DIFF_VEC (CASE_VECTOR_MODE,
5635 gen_rtx_LABEL_REF (Pmode, table_label),
5636 gen_rtvec_v (ncases, labelvec),
5637 const0_rtx, const0_rtx));
5639 emit_jump_insn (gen_rtx_ADDR_VEC (CASE_VECTOR_MODE,
5640 gen_rtvec_v (ncases, labelvec)));
5642 /* If the case insn drops through the table,
5643 after the table we must jump to the default-label.
5644 Otherwise record no drop-through after the table. */
5645 #ifdef CASE_DROPS_THROUGH
5646 emit_jump (default_label);
5652 before_case = NEXT_INSN (before_case);
5653 end = get_last_insn ();
5654 if (squeeze_notes (&before_case, &end))
5656 reorder_insns (before_case, end,
5657 thiscase->data.case_stmt.start);
5660 end_cleanup_deferral ();
5662 if (thiscase->exit_label && !exit_done)
5663 emit_label (thiscase->exit_label);
5665 POPSTACK (case_stack);
5670 /* Convert the tree NODE into a list linked by the right field, with the left
5671 field zeroed. RIGHT is used for recursion; it is a list to be placed
5672 rightmost in the resulting list. */
5674 static struct case_node *
5675 case_tree2list (struct case_node *node, struct case_node *right)
5677 struct case_node *left;
5680 right = case_tree2list (node->right, right);
5682 node->right = right;
5683 if ((left = node->left))
5686 return case_tree2list (left, node);
5692 /* Generate code to jump to LABEL if OP1 and OP2 are equal. */
5695 do_jump_if_equal (rtx op1, rtx op2, rtx label, int unsignedp)
5697 if (GET_CODE (op1) == CONST_INT && GET_CODE (op2) == CONST_INT)
5703 emit_cmp_and_jump_insns (op1, op2, EQ, NULL_RTX,
5704 (GET_MODE (op1) == VOIDmode
5705 ? GET_MODE (op2) : GET_MODE (op1)),
5709 /* Not all case values are encountered equally. This function
5710 uses a heuristic to weight case labels, in cases where that
5711 looks like a reasonable thing to do.
5713 Right now, all we try to guess is text, and we establish the
5716 chars above space: 16
5725 If we find any cases in the switch that are not either -1 or in the range
5726 of valid ASCII characters, or are control characters other than those
5727 commonly used with "\", don't treat this switch scanning text.
5729 Return 1 if these nodes are suitable for cost estimation, otherwise
5733 estimate_case_costs (case_node_ptr node)
5735 tree min_ascii = integer_minus_one_node;
5736 tree max_ascii = convert (TREE_TYPE (node->high), build_int_2 (127, 0));
5740 /* If we haven't already made the cost table, make it now. Note that the
5741 lower bound of the table is -1, not zero. */
5743 if (! cost_table_initialized)
5745 cost_table_initialized = 1;
5747 for (i = 0; i < 128; i++)
5750 COST_TABLE (i) = 16;
5751 else if (ISPUNCT (i))
5753 else if (ISCNTRL (i))
5754 COST_TABLE (i) = -1;
5757 COST_TABLE (' ') = 8;
5758 COST_TABLE ('\t') = 4;
5759 COST_TABLE ('\0') = 4;
5760 COST_TABLE ('\n') = 2;
5761 COST_TABLE ('\f') = 1;
5762 COST_TABLE ('\v') = 1;
5763 COST_TABLE ('\b') = 1;
5766 /* See if all the case expressions look like text. It is text if the
5767 constant is >= -1 and the highest constant is <= 127. Do all comparisons
5768 as signed arithmetic since we don't want to ever access cost_table with a
5769 value less than -1. Also check that none of the constants in a range
5770 are strange control characters. */
5772 for (n = node; n; n = n->right)
5774 if ((INT_CST_LT (n->low, min_ascii)) || INT_CST_LT (max_ascii, n->high))
5777 for (i = (HOST_WIDE_INT) TREE_INT_CST_LOW (n->low);
5778 i <= (HOST_WIDE_INT) TREE_INT_CST_LOW (n->high); i++)
5779 if (COST_TABLE (i) < 0)
5783 /* All interesting values are within the range of interesting
5784 ASCII characters. */
5788 /* Determine whether two case labels branch to the same target. */
5791 same_case_target_p (rtx l1, rtx l2)
5798 i1 = next_real_insn (l1);
5799 i2 = next_real_insn (l2);
5803 if (i1 && simplejump_p (i1))
5805 l1 = XEXP (SET_SRC (PATTERN (i1)), 0);
5808 if (i2 && simplejump_p (i2))
5810 l2 = XEXP (SET_SRC (PATTERN (i2)), 0);
5815 /* Delete nodes that branch to the default label from a list of
5816 case nodes. Eg. case 5: default: becomes just default: */
5819 strip_default_case_nodes (case_node_ptr *prev, rtx deflab)
5826 if (same_case_target_p (label_rtx (ptr->code_label), deflab))
5833 /* Scan an ordered list of case nodes
5834 combining those with consecutive values or ranges.
5836 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
5839 group_case_nodes (case_node_ptr head)
5841 case_node_ptr node = head;
5845 rtx lab = label_rtx (node->code_label);
5846 case_node_ptr np = node;
5848 /* Try to group the successors of NODE with NODE. */
5849 while (((np = np->right) != 0)
5850 /* Do they jump to the same place? */
5851 && same_case_target_p (label_rtx (np->code_label), lab)
5852 /* Are their ranges consecutive? */
5853 && tree_int_cst_equal (np->low,
5854 fold (build (PLUS_EXPR,
5855 TREE_TYPE (node->high),
5858 /* An overflow is not consecutive. */
5859 && tree_int_cst_lt (node->high,
5860 fold (build (PLUS_EXPR,
5861 TREE_TYPE (node->high),
5863 integer_one_node))))
5865 node->high = np->high;
5867 /* NP is the first node after NODE which can't be grouped with it.
5868 Delete the nodes in between, and move on to that node. */
5874 /* Take an ordered list of case nodes
5875 and transform them into a near optimal binary tree,
5876 on the assumption that any target code selection value is as
5877 likely as any other.
5879 The transformation is performed by splitting the ordered
5880 list into two equal sections plus a pivot. The parts are
5881 then attached to the pivot as left and right branches. Each
5882 branch is then transformed recursively. */
5885 balance_case_nodes (case_node_ptr *head, case_node_ptr parent)
5898 /* Count the number of entries on branch. Also count the ranges. */
5902 if (!tree_int_cst_equal (np->low, np->high))
5906 cost += COST_TABLE (TREE_INT_CST_LOW (np->high));
5910 cost += COST_TABLE (TREE_INT_CST_LOW (np->low));
5918 /* Split this list if it is long enough for that to help. */
5923 /* Find the place in the list that bisects the list's total cost,
5924 Here I gets half the total cost. */
5929 /* Skip nodes while their cost does not reach that amount. */
5930 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
5931 i -= COST_TABLE (TREE_INT_CST_LOW ((*npp)->high));
5932 i -= COST_TABLE (TREE_INT_CST_LOW ((*npp)->low));
5935 npp = &(*npp)->right;
5940 /* Leave this branch lopsided, but optimize left-hand
5941 side and fill in `parent' fields for right-hand side. */
5943 np->parent = parent;
5944 balance_case_nodes (&np->left, np);
5945 for (; np->right; np = np->right)
5946 np->right->parent = np;
5950 /* If there are just three nodes, split at the middle one. */
5952 npp = &(*npp)->right;
5955 /* Find the place in the list that bisects the list's total cost,
5956 where ranges count as 2.
5957 Here I gets half the total cost. */
5958 i = (i + ranges + 1) / 2;
5961 /* Skip nodes while their cost does not reach that amount. */
5962 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
5967 npp = &(*npp)->right;
5972 np->parent = parent;
5975 /* Optimize each of the two split parts. */
5976 balance_case_nodes (&np->left, np);
5977 balance_case_nodes (&np->right, np);
5981 /* Else leave this branch as one level,
5982 but fill in `parent' fields. */
5984 np->parent = parent;
5985 for (; np->right; np = np->right)
5986 np->right->parent = np;
5991 /* Search the parent sections of the case node tree
5992 to see if a test for the lower bound of NODE would be redundant.
5993 INDEX_TYPE is the type of the index expression.
5995 The instructions to generate the case decision tree are
5996 output in the same order as nodes are processed so it is
5997 known that if a parent node checks the range of the current
5998 node minus one that the current node is bounded at its lower
5999 span. Thus the test would be redundant. */
6002 node_has_low_bound (case_node_ptr node, tree index_type)
6005 case_node_ptr pnode;
6007 /* If the lower bound of this node is the lowest value in the index type,
6008 we need not test it. */
6010 if (tree_int_cst_equal (node->low, TYPE_MIN_VALUE (index_type)))
6013 /* If this node has a left branch, the value at the left must be less
6014 than that at this node, so it cannot be bounded at the bottom and
6015 we need not bother testing any further. */
6020 low_minus_one = fold (build (MINUS_EXPR, TREE_TYPE (node->low),
6021 node->low, integer_one_node));
6023 /* If the subtraction above overflowed, we can't verify anything.
6024 Otherwise, look for a parent that tests our value - 1. */
6026 if (! tree_int_cst_lt (low_minus_one, node->low))
6029 for (pnode = node->parent; pnode; pnode = pnode->parent)
6030 if (tree_int_cst_equal (low_minus_one, pnode->high))
6036 /* Search the parent sections of the case node tree
6037 to see if a test for the upper bound of NODE would be redundant.
6038 INDEX_TYPE is the type of the index expression.
6040 The instructions to generate the case decision tree are
6041 output in the same order as nodes are processed so it is
6042 known that if a parent node checks the range of the current
6043 node plus one that the current node is bounded at its upper
6044 span. Thus the test would be redundant. */
6047 node_has_high_bound (case_node_ptr node, tree index_type)
6050 case_node_ptr pnode;
6052 /* If there is no upper bound, obviously no test is needed. */
6054 if (TYPE_MAX_VALUE (index_type) == NULL)
6057 /* If the upper bound of this node is the highest value in the type
6058 of the index expression, we need not test against it. */
6060 if (tree_int_cst_equal (node->high, TYPE_MAX_VALUE (index_type)))
6063 /* If this node has a right branch, the value at the right must be greater
6064 than that at this node, so it cannot be bounded at the top and
6065 we need not bother testing any further. */
6070 high_plus_one = fold (build (PLUS_EXPR, TREE_TYPE (node->high),
6071 node->high, integer_one_node));
6073 /* If the addition above overflowed, we can't verify anything.
6074 Otherwise, look for a parent that tests our value + 1. */
6076 if (! tree_int_cst_lt (node->high, high_plus_one))
6079 for (pnode = node->parent; pnode; pnode = pnode->parent)
6080 if (tree_int_cst_equal (high_plus_one, pnode->low))
6086 /* Search the parent sections of the
6087 case node tree to see if both tests for the upper and lower
6088 bounds of NODE would be redundant. */
6091 node_is_bounded (case_node_ptr node, tree index_type)
6093 return (node_has_low_bound (node, index_type)
6094 && node_has_high_bound (node, index_type));
6097 /* Emit an unconditional jump to LABEL unless it would be dead code. */
6100 emit_jump_if_reachable (rtx label)
6102 if (GET_CODE (get_last_insn ()) != BARRIER)
6106 /* Emit step-by-step code to select a case for the value of INDEX.
6107 The thus generated decision tree follows the form of the
6108 case-node binary tree NODE, whose nodes represent test conditions.
6109 INDEX_TYPE is the type of the index of the switch.
6111 Care is taken to prune redundant tests from the decision tree
6112 by detecting any boundary conditions already checked by
6113 emitted rtx. (See node_has_high_bound, node_has_low_bound
6114 and node_is_bounded, above.)
6116 Where the test conditions can be shown to be redundant we emit
6117 an unconditional jump to the target code. As a further
6118 optimization, the subordinates of a tree node are examined to
6119 check for bounded nodes. In this case conditional and/or
6120 unconditional jumps as a result of the boundary check for the
6121 current node are arranged to target the subordinates associated
6122 code for out of bound conditions on the current node.
6124 We can assume that when control reaches the code generated here,
6125 the index value has already been compared with the parents
6126 of this node, and determined to be on the same side of each parent
6127 as this node is. Thus, if this node tests for the value 51,
6128 and a parent tested for 52, we don't need to consider
6129 the possibility of a value greater than 51. If another parent
6130 tests for the value 50, then this node need not test anything. */
6133 emit_case_nodes (rtx index, case_node_ptr node, rtx default_label,
6136 /* If INDEX has an unsigned type, we must make unsigned branches. */
6137 int unsignedp = TREE_UNSIGNED (index_type);
6138 enum machine_mode mode = GET_MODE (index);
6139 enum machine_mode imode = TYPE_MODE (index_type);
6141 /* See if our parents have already tested everything for us.
6142 If they have, emit an unconditional jump for this node. */
6143 if (node_is_bounded (node, index_type))
6144 emit_jump (label_rtx (node->code_label));
6146 else if (tree_int_cst_equal (node->low, node->high))
6148 /* Node is single valued. First see if the index expression matches
6149 this node and then check our children, if any. */
6151 do_jump_if_equal (index,
6152 convert_modes (mode, imode,
6153 expand_expr (node->low, NULL_RTX,
6156 label_rtx (node->code_label), unsignedp);
6158 if (node->right != 0 && node->left != 0)
6160 /* This node has children on both sides.
6161 Dispatch to one side or the other
6162 by comparing the index value with this node's value.
6163 If one subtree is bounded, check that one first,
6164 so we can avoid real branches in the tree. */
6166 if (node_is_bounded (node->right, index_type))
6168 emit_cmp_and_jump_insns (index,
6171 expand_expr (node->high, NULL_RTX,
6174 GT, NULL_RTX, mode, unsignedp,
6175 label_rtx (node->right->code_label));
6176 emit_case_nodes (index, node->left, default_label, index_type);
6179 else if (node_is_bounded (node->left, index_type))
6181 emit_cmp_and_jump_insns (index,
6184 expand_expr (node->high, NULL_RTX,
6187 LT, NULL_RTX, mode, unsignedp,
6188 label_rtx (node->left->code_label));
6189 emit_case_nodes (index, node->right, default_label, index_type);
6194 /* Neither node is bounded. First distinguish the two sides;
6195 then emit the code for one side at a time. */
6197 tree test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
6199 /* See if the value is on the right. */
6200 emit_cmp_and_jump_insns (index,
6203 expand_expr (node->high, NULL_RTX,
6206 GT, NULL_RTX, mode, unsignedp,
6207 label_rtx (test_label));
6209 /* Value must be on the left.
6210 Handle the left-hand subtree. */
6211 emit_case_nodes (index, node->left, default_label, index_type);
6212 /* If left-hand subtree does nothing,
6214 emit_jump_if_reachable (default_label);
6216 /* Code branches here for the right-hand subtree. */
6217 expand_label (test_label);
6218 emit_case_nodes (index, node->right, default_label, index_type);
6222 else if (node->right != 0 && node->left == 0)
6224 /* Here we have a right child but no left so we issue conditional
6225 branch to default and process the right child.
6227 Omit the conditional branch to default if we it avoid only one
6228 right child; it costs too much space to save so little time. */
6230 if (node->right->right || node->right->left
6231 || !tree_int_cst_equal (node->right->low, node->right->high))
6233 if (!node_has_low_bound (node, index_type))
6235 emit_cmp_and_jump_insns (index,
6238 expand_expr (node->high, NULL_RTX,
6241 LT, NULL_RTX, mode, unsignedp,
6245 emit_case_nodes (index, node->right, default_label, index_type);
6248 /* We cannot process node->right normally
6249 since we haven't ruled out the numbers less than
6250 this node's value. So handle node->right explicitly. */
6251 do_jump_if_equal (index,
6254 expand_expr (node->right->low, NULL_RTX,
6257 label_rtx (node->right->code_label), unsignedp);
6260 else if (node->right == 0 && node->left != 0)
6262 /* Just one subtree, on the left. */
6263 if (node->left->left || node->left->right
6264 || !tree_int_cst_equal (node->left->low, node->left->high))
6266 if (!node_has_high_bound (node, index_type))
6268 emit_cmp_and_jump_insns (index,
6271 expand_expr (node->high, NULL_RTX,
6274 GT, NULL_RTX, mode, unsignedp,
6278 emit_case_nodes (index, node->left, default_label, index_type);
6281 /* We cannot process node->left normally
6282 since we haven't ruled out the numbers less than
6283 this node's value. So handle node->left explicitly. */
6284 do_jump_if_equal (index,
6287 expand_expr (node->left->low, NULL_RTX,
6290 label_rtx (node->left->code_label), unsignedp);
6295 /* Node is a range. These cases are very similar to those for a single
6296 value, except that we do not start by testing whether this node
6297 is the one to branch to. */
6299 if (node->right != 0 && node->left != 0)
6301 /* Node has subtrees on both sides.
6302 If the right-hand subtree is bounded,
6303 test for it first, since we can go straight there.
6304 Otherwise, we need to make a branch in the control structure,
6305 then handle the two subtrees. */
6306 tree test_label = 0;
6308 if (node_is_bounded (node->right, index_type))
6309 /* Right hand node is fully bounded so we can eliminate any
6310 testing and branch directly to the target code. */
6311 emit_cmp_and_jump_insns (index,
6314 expand_expr (node->high, NULL_RTX,
6317 GT, NULL_RTX, mode, unsignedp,
6318 label_rtx (node->right->code_label));
6321 /* Right hand node requires testing.
6322 Branch to a label where we will handle it later. */
6324 test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
6325 emit_cmp_and_jump_insns (index,
6328 expand_expr (node->high, NULL_RTX,
6331 GT, NULL_RTX, mode, unsignedp,
6332 label_rtx (test_label));
6335 /* Value belongs to this node or to the left-hand subtree. */
6337 emit_cmp_and_jump_insns (index,
6340 expand_expr (node->low, NULL_RTX,
6343 GE, NULL_RTX, mode, unsignedp,
6344 label_rtx (node->code_label));
6346 /* Handle the left-hand subtree. */
6347 emit_case_nodes (index, node->left, default_label, index_type);
6349 /* If right node had to be handled later, do that now. */
6353 /* If the left-hand subtree fell through,
6354 don't let it fall into the right-hand subtree. */
6355 emit_jump_if_reachable (default_label);
6357 expand_label (test_label);
6358 emit_case_nodes (index, node->right, default_label, index_type);
6362 else if (node->right != 0 && node->left == 0)
6364 /* Deal with values to the left of this node,
6365 if they are possible. */
6366 if (!node_has_low_bound (node, index_type))
6368 emit_cmp_and_jump_insns (index,
6371 expand_expr (node->low, NULL_RTX,
6374 LT, NULL_RTX, mode, unsignedp,
6378 /* Value belongs to this node or to the right-hand subtree. */
6380 emit_cmp_and_jump_insns (index,
6383 expand_expr (node->high, NULL_RTX,
6386 LE, NULL_RTX, mode, unsignedp,
6387 label_rtx (node->code_label));
6389 emit_case_nodes (index, node->right, default_label, index_type);
6392 else if (node->right == 0 && node->left != 0)
6394 /* Deal with values to the right of this node,
6395 if they are possible. */
6396 if (!node_has_high_bound (node, index_type))
6398 emit_cmp_and_jump_insns (index,
6401 expand_expr (node->high, NULL_RTX,
6404 GT, NULL_RTX, mode, unsignedp,
6408 /* Value belongs to this node or to the left-hand subtree. */
6410 emit_cmp_and_jump_insns (index,
6413 expand_expr (node->low, NULL_RTX,
6416 GE, NULL_RTX, mode, unsignedp,
6417 label_rtx (node->code_label));
6419 emit_case_nodes (index, node->left, default_label, index_type);
6424 /* Node has no children so we check low and high bounds to remove
6425 redundant tests. Only one of the bounds can exist,
6426 since otherwise this node is bounded--a case tested already. */
6427 int high_bound = node_has_high_bound (node, index_type);
6428 int low_bound = node_has_low_bound (node, index_type);
6430 if (!high_bound && low_bound)
6432 emit_cmp_and_jump_insns (index,
6435 expand_expr (node->high, NULL_RTX,
6438 GT, NULL_RTX, mode, unsignedp,
6442 else if (!low_bound && high_bound)
6444 emit_cmp_and_jump_insns (index,
6447 expand_expr (node->low, NULL_RTX,
6450 LT, NULL_RTX, mode, unsignedp,
6453 else if (!low_bound && !high_bound)
6455 /* Widen LOW and HIGH to the same width as INDEX. */
6456 tree type = (*lang_hooks.types.type_for_mode) (mode, unsignedp);
6457 tree low = build1 (CONVERT_EXPR, type, node->low);
6458 tree high = build1 (CONVERT_EXPR, type, node->high);
6459 rtx low_rtx, new_index, new_bound;
6461 /* Instead of doing two branches, emit one unsigned branch for
6462 (index-low) > (high-low). */
6463 low_rtx = expand_expr (low, NULL_RTX, mode, 0);
6464 new_index = expand_simple_binop (mode, MINUS, index, low_rtx,
6465 NULL_RTX, unsignedp,
6467 new_bound = expand_expr (fold (build (MINUS_EXPR, type,
6471 emit_cmp_and_jump_insns (new_index, new_bound, GT, NULL_RTX,
6472 mode, 1, default_label);
6475 emit_jump (label_rtx (node->code_label));
6480 #include "gt-stmt.h"