1 /* Expands front end tree to back end RTL for GNU C-Compiler
2 Copyright (C) 1987, 88, 89, 92-98, 1999 Free Software Foundation, Inc.
4 This file is part of GNU CC.
6 GNU CC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GNU CC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU CC; see the file COPYING. If not, write to
18 the Free Software Foundation, 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
22 /* This file handles the generation of rtl code from tree structure
23 above the level of expressions, using subroutines in exp*.c and emit-rtl.c.
24 It also creates the rtl expressions for parameters and auto variables
25 and has full responsibility for allocating stack slots.
27 The functions whose names start with `expand_' are called by the
28 parser to generate RTL instructions for various kinds of constructs.
30 Some control and binding constructs require calling several such
31 functions at different times. For example, a simple if-then
32 is expanded by calling `expand_start_cond' (with the condition-expression
33 as argument) before parsing the then-clause and calling `expand_end_cond'
34 after parsing the then-clause. */
44 #include "insn-flags.h"
45 #include "insn-config.h"
46 #include "insn-codes.h"
48 #include "hard-reg-set.h"
56 #define obstack_chunk_alloc xmalloc
57 #define obstack_chunk_free free
58 struct obstack stmt_obstack;
60 /* Assume that case vectors are not pc-relative. */
61 #ifndef CASE_VECTOR_PC_RELATIVE
62 #define CASE_VECTOR_PC_RELATIVE 0
65 /* Filename and line number of last line-number note,
66 whether we actually emitted it or not. */
70 /* Nonzero if within a ({...}) grouping, in which case we must
71 always compute a value for each expr-stmt in case it is the last one. */
73 int expr_stmts_for_value;
75 /* Each time we expand an expression-statement,
76 record the expr's type and its RTL value here. */
78 static tree last_expr_type;
79 static rtx last_expr_value;
81 /* Each time we expand the end of a binding contour (in `expand_end_bindings')
82 and we emit a new NOTE_INSN_BLOCK_END note, we save a pointer to it here.
83 This is used by the `remember_end_note' function to record the endpoint
84 of each generated block in its associated BLOCK node. */
86 static rtx last_block_end_note;
88 /* Number of binding contours started so far in this function. */
90 int block_start_count;
92 /* Nonzero if function being compiled needs to
93 return the address of where it has put a structure value. */
95 extern int current_function_returns_pcc_struct;
97 /* Label that will go on parm cleanup code, if any.
98 Jumping to this label runs cleanup code for parameters, if
99 such code must be run. Following this code is the logical return label. */
101 extern rtx cleanup_label;
103 /* Label that will go on function epilogue.
104 Jumping to this label serves as a "return" instruction
105 on machines which require execution of the epilogue on all returns. */
107 extern rtx return_label;
109 /* Offset to end of allocated area of stack frame.
110 If stack grows down, this is the address of the last stack slot allocated.
111 If stack grows up, this is the address for the next slot. */
112 extern int frame_offset;
114 /* Label to jump back to for tail recursion, or 0 if we have
115 not yet needed one for this function. */
116 extern rtx tail_recursion_label;
118 /* Place after which to insert the tail_recursion_label if we need one. */
119 extern rtx tail_recursion_reentry;
121 /* Location at which to save the argument pointer if it will need to be
122 referenced. There are two cases where this is done: if nonlocal gotos
123 exist, or if vars whose is an offset from the argument pointer will be
124 needed by inner routines. */
126 extern rtx arg_pointer_save_area;
128 /* Chain of all RTL_EXPRs that have insns in them. */
129 extern tree rtl_expr_chain;
131 /* Functions and data structures for expanding case statements. */
133 /* Case label structure, used to hold info on labels within case
134 statements. We handle "range" labels; for a single-value label
135 as in C, the high and low limits are the same.
137 An AVL tree of case nodes is initially created, and later transformed
138 to a list linked via the RIGHT fields in the nodes. Nodes with
139 higher case values are later in the list.
141 Switch statements can be output in one of two forms. A branch table
142 is used if there are more than a few labels and the labels are dense
143 within the range between the smallest and largest case value. If a
144 branch table is used, no further manipulations are done with the case
147 The alternative to the use of a branch table is to generate a series
148 of compare and jump insns. When that is done, we use the LEFT, RIGHT,
149 and PARENT fields to hold a binary tree. Initially the tree is
150 totally unbalanced, with everything on the right. We balance the tree
151 with nodes on the left having lower case values than the parent
152 and nodes on the right having higher values. We then output the tree
157 struct case_node *left; /* Left son in binary tree */
158 struct case_node *right; /* Right son in binary tree; also node chain */
159 struct case_node *parent; /* Parent of node in binary tree */
160 tree low; /* Lowest index value for this label */
161 tree high; /* Highest index value for this label */
162 tree code_label; /* Label to jump to when node matches */
166 typedef struct case_node case_node;
167 typedef struct case_node *case_node_ptr;
169 /* These are used by estimate_case_costs and balance_case_nodes. */
171 /* This must be a signed type, and non-ANSI compilers lack signed char. */
172 static short *cost_table;
173 static int use_cost_table;
175 /* Stack of control and binding constructs we are currently inside.
177 These constructs begin when you call `expand_start_WHATEVER'
178 and end when you call `expand_end_WHATEVER'. This stack records
179 info about how the construct began that tells the end-function
180 what to do. It also may provide information about the construct
181 to alter the behavior of other constructs within the body.
182 For example, they may affect the behavior of C `break' and `continue'.
184 Each construct gets one `struct nesting' object.
185 All of these objects are chained through the `all' field.
186 `nesting_stack' points to the first object (innermost construct).
187 The position of an entry on `nesting_stack' is in its `depth' field.
189 Each type of construct has its own individual stack.
190 For example, loops have `loop_stack'. Each object points to the
191 next object of the same type through the `next' field.
193 Some constructs are visible to `break' exit-statements and others
194 are not. Which constructs are visible depends on the language.
195 Therefore, the data structure allows each construct to be visible
196 or not, according to the args given when the construct is started.
197 The construct is visible if the `exit_label' field is non-null.
198 In that case, the value should be a CODE_LABEL rtx. */
203 struct nesting *next;
208 /* For conds (if-then and if-then-else statements). */
211 /* Label for the end of the if construct.
212 There is none if EXITFLAG was not set
213 and no `else' has been seen yet. */
215 /* Label for the end of this alternative.
216 This may be the end of the if or the next else/elseif. */
222 /* Label at the top of the loop; place to loop back to. */
224 /* Label at the end of the whole construct. */
226 /* Label before a jump that branches to the end of the whole
227 construct. This is where destructors go if any. */
229 /* Label for `continue' statement to jump to;
230 this is in front of the stepper of the loop. */
233 /* For variable binding contours. */
236 /* Sequence number of this binding contour within the function,
237 in order of entry. */
238 int block_start_count;
239 /* Nonzero => value to restore stack to on exit. */
241 /* The NOTE that starts this contour.
242 Used by expand_goto to check whether the destination
243 is within each contour or not. */
245 /* Innermost containing binding contour that has a stack level. */
246 struct nesting *innermost_stack_block;
247 /* List of cleanups to be run on exit from this contour.
248 This is a list of expressions to be evaluated.
249 The TREE_PURPOSE of each link is the ..._DECL node
250 which the cleanup pertains to. */
252 /* List of cleanup-lists of blocks containing this block,
253 as they were at the locus where this block appears.
254 There is an element for each containing block,
255 ordered innermost containing block first.
256 The tail of this list can be 0,
257 if all remaining elements would be empty lists.
258 The element's TREE_VALUE is the cleanup-list of that block,
259 which may be null. */
261 /* Chain of labels defined inside this binding contour.
262 For contours that have stack levels or cleanups. */
263 struct label_chain *label_chain;
264 /* Number of function calls seen, as of start of this block. */
265 int function_call_count;
266 /* Nonzero if this is associated with a EH region. */
267 int exception_region;
268 /* The saved target_temp_slot_level from our outer block.
269 We may reset target_temp_slot_level to be the level of
270 this block, if that is done, target_temp_slot_level
271 reverts to the saved target_temp_slot_level at the very
273 int target_temp_slot_level;
274 /* True if we are currently emitting insns in an area of
275 output code that is controlled by a conditional
276 expression. This is used by the cleanup handling code to
277 generate conditional cleanup actions. */
278 int conditional_code;
279 /* A place to move the start of the exception region for any
280 of the conditional cleanups, must be at the end or after
281 the start of the last unconditional cleanup, and before any
282 conditional branch points. */
283 rtx last_unconditional_cleanup;
284 /* When in a conditional context, this is the specific
285 cleanup list associated with last_unconditional_cleanup,
286 where we place the conditionalized cleanups. */
289 /* For switch (C) or case (Pascal) statements,
290 and also for dummies (see `expand_start_case_dummy'). */
293 /* The insn after which the case dispatch should finally
294 be emitted. Zero for a dummy. */
296 /* A list of case labels; it is first built as an AVL tree.
297 During expand_end_case, this is converted to a list, and may be
298 rearranged into a nearly balanced binary tree. */
299 struct case_node *case_list;
300 /* Label to jump to if no case matches. */
302 /* The expression to be dispatched on. */
304 /* Type that INDEX_EXPR should be converted to. */
306 /* Number of range exprs in case statement. */
308 /* Name of this kind of statement, for warnings. */
309 const char *printname;
310 /* Used to save no_line_numbers till we see the first case label.
311 We set this to -1 when we see the first case label in this
313 int line_number_status;
318 /* Chain of all pending binding contours. */
319 struct nesting *block_stack;
321 /* If any new stacks are added here, add them to POPSTACKS too. */
323 /* Chain of all pending binding contours that restore stack levels
325 struct nesting *stack_block_stack;
327 /* Chain of all pending conditional statements. */
328 struct nesting *cond_stack;
330 /* Chain of all pending loops. */
331 struct nesting *loop_stack;
333 /* Chain of all pending case or switch statements. */
334 struct nesting *case_stack;
336 /* Separate chain including all of the above,
337 chained through the `all' field. */
338 struct nesting *nesting_stack;
340 /* Number of entries on nesting_stack now. */
343 /* Allocate and return a new `struct nesting'. */
345 #define ALLOC_NESTING() \
346 (struct nesting *) obstack_alloc (&stmt_obstack, sizeof (struct nesting))
348 /* Pop the nesting stack element by element until we pop off
349 the element which is at the top of STACK.
350 Update all the other stacks, popping off elements from them
351 as we pop them from nesting_stack. */
353 #define POPSTACK(STACK) \
354 do { struct nesting *target = STACK; \
355 struct nesting *this; \
356 do { this = nesting_stack; \
357 if (loop_stack == this) \
358 loop_stack = loop_stack->next; \
359 if (cond_stack == this) \
360 cond_stack = cond_stack->next; \
361 if (block_stack == this) \
362 block_stack = block_stack->next; \
363 if (stack_block_stack == this) \
364 stack_block_stack = stack_block_stack->next; \
365 if (case_stack == this) \
366 case_stack = case_stack->next; \
367 nesting_depth = nesting_stack->depth - 1; \
368 nesting_stack = this->all; \
369 obstack_free (&stmt_obstack, this); } \
370 while (this != target); } while (0)
372 /* In some cases it is impossible to generate code for a forward goto
373 until the label definition is seen. This happens when it may be necessary
374 for the goto to reset the stack pointer: we don't yet know how to do that.
375 So expand_goto puts an entry on this fixup list.
376 Each time a binding contour that resets the stack is exited,
378 If the target label has now been defined, we can insert the proper code. */
382 /* Points to following fixup. */
383 struct goto_fixup *next;
384 /* Points to the insn before the jump insn.
385 If more code must be inserted, it goes after this insn. */
387 /* The LABEL_DECL that this jump is jumping to, or 0
388 for break, continue or return. */
390 /* The BLOCK for the place where this goto was found. */
392 /* The CODE_LABEL rtx that this is jumping to. */
394 /* Number of binding contours started in current function
395 before the label reference. */
396 int block_start_count;
397 /* The outermost stack level that should be restored for this jump.
398 Each time a binding contour that resets the stack is exited,
399 if the target label is *not* yet defined, this slot is updated. */
401 /* List of lists of cleanup expressions to be run by this goto.
402 There is one element for each block that this goto is within.
403 The tail of this list can be 0,
404 if all remaining elements would be empty.
405 The TREE_VALUE contains the cleanup list of that block as of the
406 time this goto was seen.
407 The TREE_ADDRESSABLE flag is 1 for a block that has been exited. */
408 tree cleanup_list_list;
411 static struct goto_fixup *goto_fixup_chain;
413 /* Within any binding contour that must restore a stack level,
414 all labels are recorded with a chain of these structures. */
418 /* Points to following fixup. */
419 struct label_chain *next;
424 /* Non-zero if we are using EH to handle cleanus. */
425 static int using_eh_for_cleanups_p = 0;
428 static int n_occurrences PROTO((int, const char *));
429 static void expand_goto_internal PROTO((tree, rtx, rtx));
430 static int expand_fixup PROTO((tree, rtx, rtx));
431 static rtx expand_nl_handler_label PROTO((rtx, rtx));
432 static void expand_nl_goto_receiver PROTO((void));
433 static void expand_nl_goto_receivers PROTO((struct nesting *));
434 static void fixup_gotos PROTO((struct nesting *, rtx, tree,
436 static void expand_null_return_1 PROTO((rtx, int));
437 static void expand_value_return PROTO((rtx));
438 static int tail_recursion_args PROTO((tree, tree));
439 static void expand_cleanups PROTO((tree, tree, int, int));
440 static void check_seenlabel PROTO((void));
441 static void do_jump_if_equal PROTO((rtx, rtx, rtx, int));
442 static int estimate_case_costs PROTO((case_node_ptr));
443 static void group_case_nodes PROTO((case_node_ptr));
444 static void balance_case_nodes PROTO((case_node_ptr *,
446 static int node_has_low_bound PROTO((case_node_ptr, tree));
447 static int node_has_high_bound PROTO((case_node_ptr, tree));
448 static int node_is_bounded PROTO((case_node_ptr, tree));
449 static void emit_jump_if_reachable PROTO((rtx));
450 static void emit_case_nodes PROTO((rtx, case_node_ptr, rtx, tree));
451 static int add_case_node PROTO((tree, tree, tree, tree *));
452 static struct case_node *case_tree2list PROTO((case_node *, case_node *));
455 using_eh_for_cleanups ()
457 using_eh_for_cleanups_p = 1;
463 gcc_obstack_init (&stmt_obstack);
468 init_stmt_for_function ()
470 /* We are not currently within any block, conditional, loop or case. */
472 stack_block_stack = 0;
479 block_start_count = 0;
481 /* No gotos have been expanded yet. */
482 goto_fixup_chain = 0;
484 /* We are not processing a ({...}) grouping. */
485 expr_stmts_for_value = 0;
488 init_eh_for_function ();
495 p->block_stack = block_stack;
496 p->stack_block_stack = stack_block_stack;
497 p->cond_stack = cond_stack;
498 p->loop_stack = loop_stack;
499 p->case_stack = case_stack;
500 p->nesting_stack = nesting_stack;
501 p->nesting_depth = nesting_depth;
502 p->block_start_count = block_start_count;
503 p->last_expr_type = last_expr_type;
504 p->last_expr_value = last_expr_value;
505 p->expr_stmts_for_value = expr_stmts_for_value;
506 p->emit_filename = emit_filename;
507 p->emit_lineno = emit_lineno;
508 p->goto_fixup_chain = goto_fixup_chain;
513 restore_stmt_status (p)
516 block_stack = p->block_stack;
517 stack_block_stack = p->stack_block_stack;
518 cond_stack = p->cond_stack;
519 loop_stack = p->loop_stack;
520 case_stack = p->case_stack;
521 nesting_stack = p->nesting_stack;
522 nesting_depth = p->nesting_depth;
523 block_start_count = p->block_start_count;
524 last_expr_type = p->last_expr_type;
525 last_expr_value = p->last_expr_value;
526 expr_stmts_for_value = p->expr_stmts_for_value;
527 emit_filename = p->emit_filename;
528 emit_lineno = p->emit_lineno;
529 goto_fixup_chain = p->goto_fixup_chain;
530 restore_eh_status (p);
533 /* Emit a no-op instruction. */
540 last_insn = get_last_insn ();
542 && (GET_CODE (last_insn) == CODE_LABEL
543 || (GET_CODE (last_insn) == NOTE
544 && prev_real_insn (last_insn) == 0)))
545 emit_insn (gen_nop ());
548 /* Return the rtx-label that corresponds to a LABEL_DECL,
549 creating it if necessary. */
555 if (TREE_CODE (label) != LABEL_DECL)
558 if (DECL_RTL (label))
559 return DECL_RTL (label);
561 return DECL_RTL (label) = gen_label_rtx ();
564 /* Add an unconditional jump to LABEL as the next sequential instruction. */
570 do_pending_stack_adjust ();
571 emit_jump_insn (gen_jump (label));
575 /* Emit code to jump to the address
576 specified by the pointer expression EXP. */
579 expand_computed_goto (exp)
582 rtx x = expand_expr (exp, NULL_RTX, VOIDmode, 0);
584 #ifdef POINTERS_EXTEND_UNSIGNED
585 x = convert_memory_address (Pmode, x);
589 /* Be sure the function is executable. */
590 if (current_function_check_memory_usage)
591 emit_library_call (chkr_check_exec_libfunc, 1,
592 VOIDmode, 1, x, ptr_mode);
594 do_pending_stack_adjust ();
595 emit_indirect_jump (x);
597 current_function_has_computed_jump = 1;
600 /* Handle goto statements and the labels that they can go to. */
602 /* Specify the location in the RTL code of a label LABEL,
603 which is a LABEL_DECL tree node.
605 This is used for the kind of label that the user can jump to with a
606 goto statement, and for alternatives of a switch or case statement.
607 RTL labels generated for loops and conditionals don't go through here;
608 they are generated directly at the RTL level, by other functions below.
610 Note that this has nothing to do with defining label *names*.
611 Languages vary in how they do that and what that even means. */
617 struct label_chain *p;
619 do_pending_stack_adjust ();
620 emit_label (label_rtx (label));
621 if (DECL_NAME (label))
622 LABEL_NAME (DECL_RTL (label)) = IDENTIFIER_POINTER (DECL_NAME (label));
624 if (stack_block_stack != 0)
626 p = (struct label_chain *) oballoc (sizeof (struct label_chain));
627 p->next = stack_block_stack->data.block.label_chain;
628 stack_block_stack->data.block.label_chain = p;
633 /* Declare that LABEL (a LABEL_DECL) may be used for nonlocal gotos
634 from nested functions. */
637 declare_nonlocal_label (label)
640 rtx slot = assign_stack_local (Pmode, GET_MODE_SIZE (Pmode), 0);
642 nonlocal_labels = tree_cons (NULL_TREE, label, nonlocal_labels);
643 LABEL_PRESERVE_P (label_rtx (label)) = 1;
644 if (nonlocal_goto_handler_slots == 0)
646 emit_stack_save (SAVE_NONLOCAL,
647 &nonlocal_goto_stack_level,
648 PREV_INSN (tail_recursion_reentry));
650 nonlocal_goto_handler_slots
651 = gen_rtx_EXPR_LIST (VOIDmode, slot, nonlocal_goto_handler_slots);
654 /* Generate RTL code for a `goto' statement with target label LABEL.
655 LABEL should be a LABEL_DECL tree node that was or will later be
656 defined with `expand_label'. */
664 /* Check for a nonlocal goto to a containing function. */
665 context = decl_function_context (label);
666 if (context != 0 && context != current_function_decl)
668 struct function *p = find_function_data (context);
669 rtx label_ref = gen_rtx_LABEL_REF (Pmode, label_rtx (label));
670 rtx temp, handler_slot;
673 /* Find the corresponding handler slot for this label. */
674 handler_slot = p->nonlocal_goto_handler_slots;
675 for (link = p->nonlocal_labels; TREE_VALUE (link) != label;
676 link = TREE_CHAIN (link))
677 handler_slot = XEXP (handler_slot, 1);
678 handler_slot = XEXP (handler_slot, 0);
680 p->has_nonlocal_label = 1;
681 current_function_has_nonlocal_goto = 1;
682 LABEL_REF_NONLOCAL_P (label_ref) = 1;
684 /* Copy the rtl for the slots so that they won't be shared in
685 case the virtual stack vars register gets instantiated differently
686 in the parent than in the child. */
688 #if HAVE_nonlocal_goto
689 if (HAVE_nonlocal_goto)
690 emit_insn (gen_nonlocal_goto (lookup_static_chain (label),
691 copy_rtx (handler_slot),
692 copy_rtx (p->nonlocal_goto_stack_level),
699 /* Restore frame pointer for containing function.
700 This sets the actual hard register used for the frame pointer
701 to the location of the function's incoming static chain info.
702 The non-local goto handler will then adjust it to contain the
703 proper value and reload the argument pointer, if needed. */
704 emit_move_insn (hard_frame_pointer_rtx, lookup_static_chain (label));
706 /* We have now loaded the frame pointer hardware register with
707 the address of that corresponds to the start of the virtual
708 stack vars. So replace virtual_stack_vars_rtx in all
709 addresses we use with stack_pointer_rtx. */
711 /* Get addr of containing function's current nonlocal goto handler,
712 which will do any cleanups and then jump to the label. */
713 addr = copy_rtx (handler_slot);
714 temp = copy_to_reg (replace_rtx (addr, virtual_stack_vars_rtx,
715 hard_frame_pointer_rtx));
717 /* Restore the stack pointer. Note this uses fp just restored. */
718 addr = p->nonlocal_goto_stack_level;
720 addr = replace_rtx (copy_rtx (addr),
721 virtual_stack_vars_rtx,
722 hard_frame_pointer_rtx);
724 emit_stack_restore (SAVE_NONLOCAL, addr, NULL_RTX);
726 /* USE of hard_frame_pointer_rtx added for consistency; not clear if
728 emit_insn (gen_rtx_USE (VOIDmode, hard_frame_pointer_rtx));
729 emit_insn (gen_rtx_USE (VOIDmode, stack_pointer_rtx));
730 emit_indirect_jump (temp);
734 expand_goto_internal (label, label_rtx (label), NULL_RTX);
737 /* Generate RTL code for a `goto' statement with target label BODY.
738 LABEL should be a LABEL_REF.
739 LAST_INSN, if non-0, is the rtx we should consider as the last
740 insn emitted (for the purposes of cleaning up a return). */
743 expand_goto_internal (body, label, last_insn)
748 struct nesting *block;
751 if (GET_CODE (label) != CODE_LABEL)
754 /* If label has already been defined, we can tell now
755 whether and how we must alter the stack level. */
757 if (PREV_INSN (label) != 0)
759 /* Find the innermost pending block that contains the label.
760 (Check containment by comparing insn-uids.)
761 Then restore the outermost stack level within that block,
762 and do cleanups of all blocks contained in it. */
763 for (block = block_stack; block; block = block->next)
765 if (INSN_UID (block->data.block.first_insn) < INSN_UID (label))
767 if (block->data.block.stack_level != 0)
768 stack_level = block->data.block.stack_level;
769 /* Execute the cleanups for blocks we are exiting. */
770 if (block->data.block.cleanups != 0)
772 expand_cleanups (block->data.block.cleanups, NULL_TREE, 1, 1);
773 do_pending_stack_adjust ();
779 /* Ensure stack adjust isn't done by emit_jump, as this
780 would clobber the stack pointer. This one should be
781 deleted as dead by flow. */
782 clear_pending_stack_adjust ();
783 do_pending_stack_adjust ();
784 emit_stack_restore (SAVE_BLOCK, stack_level, NULL_RTX);
787 if (body != 0 && DECL_TOO_LATE (body))
788 error ("jump to `%s' invalidly jumps into binding contour",
789 IDENTIFIER_POINTER (DECL_NAME (body)));
791 /* Label not yet defined: may need to put this goto
792 on the fixup list. */
793 else if (! expand_fixup (body, label, last_insn))
795 /* No fixup needed. Record that the label is the target
796 of at least one goto that has no fixup. */
798 TREE_ADDRESSABLE (body) = 1;
804 /* Generate if necessary a fixup for a goto
805 whose target label in tree structure (if any) is TREE_LABEL
806 and whose target in rtl is RTL_LABEL.
808 If LAST_INSN is nonzero, we pretend that the jump appears
809 after insn LAST_INSN instead of at the current point in the insn stream.
811 The fixup will be used later to insert insns just before the goto.
812 Those insns will restore the stack level as appropriate for the
813 target label, and will (in the case of C++) also invoke any object
814 destructors which have to be invoked when we exit the scopes which
815 are exited by the goto.
817 Value is nonzero if a fixup is made. */
820 expand_fixup (tree_label, rtl_label, last_insn)
825 struct nesting *block, *end_block;
827 /* See if we can recognize which block the label will be output in.
828 This is possible in some very common cases.
829 If we succeed, set END_BLOCK to that block.
830 Otherwise, set it to 0. */
833 && (rtl_label == cond_stack->data.cond.endif_label
834 || rtl_label == cond_stack->data.cond.next_label))
835 end_block = cond_stack;
836 /* If we are in a loop, recognize certain labels which
837 are likely targets. This reduces the number of fixups
838 we need to create. */
840 && (rtl_label == loop_stack->data.loop.start_label
841 || rtl_label == loop_stack->data.loop.end_label
842 || rtl_label == loop_stack->data.loop.continue_label))
843 end_block = loop_stack;
847 /* Now set END_BLOCK to the binding level to which we will return. */
851 struct nesting *next_block = end_block->all;
854 /* First see if the END_BLOCK is inside the innermost binding level.
855 If so, then no cleanups or stack levels are relevant. */
856 while (next_block && next_block != block)
857 next_block = next_block->all;
862 /* Otherwise, set END_BLOCK to the innermost binding level
863 which is outside the relevant control-structure nesting. */
864 next_block = block_stack->next;
865 for (block = block_stack; block != end_block; block = block->all)
866 if (block == next_block)
867 next_block = next_block->next;
868 end_block = next_block;
871 /* Does any containing block have a stack level or cleanups?
872 If not, no fixup is needed, and that is the normal case
873 (the only case, for standard C). */
874 for (block = block_stack; block != end_block; block = block->next)
875 if (block->data.block.stack_level != 0
876 || block->data.block.cleanups != 0)
879 if (block != end_block)
881 /* Ok, a fixup is needed. Add a fixup to the list of such. */
882 struct goto_fixup *fixup
883 = (struct goto_fixup *) oballoc (sizeof (struct goto_fixup));
884 /* In case an old stack level is restored, make sure that comes
885 after any pending stack adjust. */
886 /* ?? If the fixup isn't to come at the present position,
887 doing the stack adjust here isn't useful. Doing it with our
888 settings at that location isn't useful either. Let's hope
891 do_pending_stack_adjust ();
892 fixup->target = tree_label;
893 fixup->target_rtl = rtl_label;
895 /* Create a BLOCK node and a corresponding matched set of
896 NOTE_INSN_BEGIN_BLOCK and NOTE_INSN_END_BLOCK notes at
897 this point. The notes will encapsulate any and all fixup
898 code which we might later insert at this point in the insn
899 stream. Also, the BLOCK node will be the parent (i.e. the
900 `SUPERBLOCK') of any other BLOCK nodes which we might create
901 later on when we are expanding the fixup code.
903 Note that optimization passes (including expand_end_loop)
904 might move the *_BLOCK notes away, so we use a NOTE_INSN_DELETED
908 register rtx original_before_jump
909 = last_insn ? last_insn : get_last_insn ();
914 start = emit_note (NULL_PTR, NOTE_INSN_BLOCK_BEG);
915 fixup->before_jump = emit_note (NULL_PTR, NOTE_INSN_DELETED);
916 last_block_end_note = emit_note (NULL_PTR, NOTE_INSN_BLOCK_END);
917 fixup->context = poplevel (1, 0, 0); /* Create the BLOCK node now! */
919 emit_insns_after (start, original_before_jump);
922 fixup->block_start_count = block_start_count;
923 fixup->stack_level = 0;
924 fixup->cleanup_list_list
925 = ((block->data.block.outer_cleanups
926 || block->data.block.cleanups)
927 ? tree_cons (NULL_TREE, block->data.block.cleanups,
928 block->data.block.outer_cleanups)
930 fixup->next = goto_fixup_chain;
931 goto_fixup_chain = fixup;
939 /* Expand any needed fixups in the outputmost binding level of the
940 function. FIRST_INSN is the first insn in the function. */
943 expand_fixups (first_insn)
946 fixup_gotos (NULL_PTR, NULL_RTX, NULL_TREE, first_insn, 0);
949 /* When exiting a binding contour, process all pending gotos requiring fixups.
950 THISBLOCK is the structure that describes the block being exited.
951 STACK_LEVEL is the rtx for the stack level to restore exiting this contour.
952 CLEANUP_LIST is a list of expressions to evaluate on exiting this contour.
953 FIRST_INSN is the insn that began this contour.
955 Gotos that jump out of this contour must restore the
956 stack level and do the cleanups before actually jumping.
958 DONT_JUMP_IN nonzero means report error there is a jump into this
959 contour from before the beginning of the contour.
960 This is also done if STACK_LEVEL is nonzero. */
963 fixup_gotos (thisblock, stack_level, cleanup_list, first_insn, dont_jump_in)
964 struct nesting *thisblock;
970 register struct goto_fixup *f, *prev;
972 /* F is the fixup we are considering; PREV is the previous one. */
973 /* We run this loop in two passes so that cleanups of exited blocks
974 are run first, and blocks that are exited are marked so
977 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
979 /* Test for a fixup that is inactive because it is already handled. */
980 if (f->before_jump == 0)
982 /* Delete inactive fixup from the chain, if that is easy to do. */
984 prev->next = f->next;
986 /* Has this fixup's target label been defined?
987 If so, we can finalize it. */
988 else if (PREV_INSN (f->target_rtl) != 0)
990 register rtx cleanup_insns;
992 /* Get the first non-label after the label
993 this goto jumps to. If that's before this scope begins,
994 we don't have a jump into the scope. */
995 rtx after_label = f->target_rtl;
996 while (after_label != 0 && GET_CODE (after_label) == CODE_LABEL)
997 after_label = NEXT_INSN (after_label);
999 /* If this fixup jumped into this contour from before the beginning
1000 of this contour, report an error. */
1001 /* ??? Bug: this does not detect jumping in through intermediate
1002 blocks that have stack levels or cleanups.
1003 It detects only a problem with the innermost block
1004 around the label. */
1006 && (dont_jump_in || stack_level || cleanup_list)
1007 /* If AFTER_LABEL is 0, it means the jump goes to the end
1008 of the rtl, which means it jumps into this scope. */
1009 && (after_label == 0
1010 || INSN_UID (first_insn) < INSN_UID (after_label))
1011 && INSN_UID (first_insn) > INSN_UID (f->before_jump)
1012 && ! DECL_ERROR_ISSUED (f->target))
1014 error_with_decl (f->target,
1015 "label `%s' used before containing binding contour");
1016 /* Prevent multiple errors for one label. */
1017 DECL_ERROR_ISSUED (f->target) = 1;
1020 /* We will expand the cleanups into a sequence of their own and
1021 then later on we will attach this new sequence to the insn
1022 stream just ahead of the actual jump insn. */
1026 /* Temporarily restore the lexical context where we will
1027 logically be inserting the fixup code. We do this for the
1028 sake of getting the debugging information right. */
1031 set_block (f->context);
1033 /* Expand the cleanups for blocks this jump exits. */
1034 if (f->cleanup_list_list)
1037 for (lists = f->cleanup_list_list; lists; lists = TREE_CHAIN (lists))
1038 /* Marked elements correspond to blocks that have been closed.
1039 Do their cleanups. */
1040 if (TREE_ADDRESSABLE (lists)
1041 && TREE_VALUE (lists) != 0)
1043 expand_cleanups (TREE_VALUE (lists), NULL_TREE, 1, 1);
1044 /* Pop any pushes done in the cleanups,
1045 in case function is about to return. */
1046 do_pending_stack_adjust ();
1050 /* Restore stack level for the biggest contour that this
1051 jump jumps out of. */
1053 emit_stack_restore (SAVE_BLOCK, f->stack_level, f->before_jump);
1055 /* Finish up the sequence containing the insns which implement the
1056 necessary cleanups, and then attach that whole sequence to the
1057 insn stream just ahead of the actual jump insn. Attaching it
1058 at that point insures that any cleanups which are in fact
1059 implicit C++ object destructions (which must be executed upon
1060 leaving the block) appear (to the debugger) to be taking place
1061 in an area of the generated code where the object(s) being
1062 destructed are still "in scope". */
1064 cleanup_insns = get_insns ();
1068 emit_insns_after (cleanup_insns, f->before_jump);
1075 /* For any still-undefined labels, do the cleanups for this block now.
1076 We must do this now since items in the cleanup list may go out
1077 of scope when the block ends. */
1078 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
1079 if (f->before_jump != 0
1080 && PREV_INSN (f->target_rtl) == 0
1081 /* Label has still not appeared. If we are exiting a block with
1082 a stack level to restore, that started before the fixup,
1083 mark this stack level as needing restoration
1084 when the fixup is later finalized. */
1086 /* Note: if THISBLOCK == 0 and we have a label that hasn't appeared, it
1087 means the label is undefined. That's erroneous, but possible. */
1088 && (thisblock->data.block.block_start_count
1089 <= f->block_start_count))
1091 tree lists = f->cleanup_list_list;
1094 for (; lists; lists = TREE_CHAIN (lists))
1095 /* If the following elt. corresponds to our containing block
1096 then the elt. must be for this block. */
1097 if (TREE_CHAIN (lists) == thisblock->data.block.outer_cleanups)
1101 set_block (f->context);
1102 expand_cleanups (TREE_VALUE (lists), NULL_TREE, 1, 1);
1103 do_pending_stack_adjust ();
1104 cleanup_insns = get_insns ();
1107 if (cleanup_insns != 0)
1109 = emit_insns_after (cleanup_insns, f->before_jump);
1111 f->cleanup_list_list = TREE_CHAIN (lists);
1115 f->stack_level = stack_level;
1119 /* Return the number of times character C occurs in string S. */
1121 n_occurrences (c, s)
1131 /* Generate RTL for an asm statement (explicit assembler code).
1132 BODY is a STRING_CST node containing the assembler code text,
1133 or an ADDR_EXPR containing a STRING_CST. */
1139 if (current_function_check_memory_usage)
1141 error ("`asm' cannot be used with `-fcheck-memory-usage'");
1145 if (TREE_CODE (body) == ADDR_EXPR)
1146 body = TREE_OPERAND (body, 0);
1148 emit_insn (gen_rtx_ASM_INPUT (VOIDmode,
1149 TREE_STRING_POINTER (body)));
1153 /* Generate RTL for an asm statement with arguments.
1154 STRING is the instruction template.
1155 OUTPUTS is a list of output arguments (lvalues); INPUTS a list of inputs.
1156 Each output or input has an expression in the TREE_VALUE and
1157 a constraint-string in the TREE_PURPOSE.
1158 CLOBBERS is a list of STRING_CST nodes each naming a hard register
1159 that is clobbered by this insn.
1161 Not all kinds of lvalue that may appear in OUTPUTS can be stored directly.
1162 Some elements of OUTPUTS may be replaced with trees representing temporary
1163 values. The caller should copy those temporary values to the originally
1166 VOL nonzero means the insn is volatile; don't optimize it. */
1169 expand_asm_operands (string, outputs, inputs, clobbers, vol, filename, line)
1170 tree string, outputs, inputs, clobbers;
1175 rtvec argvec, constraints;
1177 int ninputs = list_length (inputs);
1178 int noutputs = list_length (outputs);
1183 /* Vector of RTX's of evaluated output operands. */
1184 rtx *output_rtx = (rtx *) alloca (noutputs * sizeof (rtx));
1185 int *inout_opnum = (int *) alloca (noutputs * sizeof (int));
1186 enum machine_mode *inout_mode
1187 = (enum machine_mode *) alloca (noutputs * sizeof (enum machine_mode));
1188 /* The insn we have emitted. */
1191 /* An ASM with no outputs needs to be treated as volatile, for now. */
1195 if (current_function_check_memory_usage)
1197 error ("`asm' cannot be used with `-fcheck-memory-usage'");
1201 /* Count the number of meaningful clobbered registers, ignoring what
1202 we would ignore later. */
1204 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1206 char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1207 i = decode_reg_name (regname);
1208 if (i >= 0 || i == -4)
1211 error ("unknown register name `%s' in `asm'", regname);
1216 /* Check that the number of alternatives is constant across all
1218 if (outputs || inputs)
1220 tree tmp = TREE_PURPOSE (outputs ? outputs : inputs);
1221 int nalternatives = n_occurrences (',', TREE_STRING_POINTER (tmp));
1224 if (nalternatives + 1 > MAX_RECOG_ALTERNATIVES)
1226 error ("too many alternatives in `asm'");
1233 char *constraint = TREE_STRING_POINTER (TREE_PURPOSE (tmp));
1234 if (n_occurrences (',', constraint) != nalternatives)
1236 error ("operand constraints for `asm' differ in number of alternatives");
1239 if (TREE_CHAIN (tmp))
1240 tmp = TREE_CHAIN (tmp);
1242 tmp = next, next = 0;
1246 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1248 tree val = TREE_VALUE (tail);
1249 tree type = TREE_TYPE (val);
1258 /* If there's an erroneous arg, emit no insn. */
1259 if (TREE_TYPE (val) == error_mark_node)
1262 /* Make sure constraint has `=' and does not have `+'. Also, see
1263 if it allows any register. Be liberal on the latter test, since
1264 the worst that happens if we get it wrong is we issue an error
1267 c_len = TREE_STRING_LENGTH (TREE_PURPOSE (tail)) - 1;
1268 constraint = TREE_STRING_POINTER (TREE_PURPOSE (tail));
1270 /* Allow the `=' or `+' to not be at the beginning of the string,
1271 since it wasn't explicitly documented that way, and there is a
1272 large body of code that puts it last. Swap the character to
1273 the front, so as not to uglify any place else. */
1277 if ((p = strchr (constraint, '=')) != NULL)
1279 if ((p = strchr (constraint, '+')) != NULL)
1282 error ("output operand constraint lacks `='");
1286 if (p != constraint)
1289 bcopy (constraint, constraint+1, p-constraint);
1292 warning ("output constraint `%c' for operand %d is not at the beginning", j, i);
1295 is_inout = constraint[0] == '+';
1296 /* Replace '+' with '='. */
1297 constraint[0] = '=';
1298 /* Make sure we can specify the matching operand. */
1299 if (is_inout && i > 9)
1301 error ("output operand constraint %d contains `+'", i);
1305 for (j = 1; j < c_len; j++)
1306 switch (constraint[j])
1310 error ("operand constraint contains '+' or '=' at illegal position.");
1314 if (i + 1 == ninputs + noutputs)
1316 error ("`%%' constraint used with last operand");
1321 case '?': case '!': case '*': case '&':
1322 case 'E': case 'F': case 'G': case 'H':
1323 case 's': case 'i': case 'n':
1324 case 'I': case 'J': case 'K': case 'L': case 'M':
1325 case 'N': case 'O': case 'P': case ',':
1326 #ifdef EXTRA_CONSTRAINT
1327 case 'Q': case 'R': case 'S': case 'T': case 'U':
1331 case '0': case '1': case '2': case '3': case '4':
1332 case '5': case '6': case '7': case '8': case '9':
1333 error ("matching constraint not valid in output operand");
1336 case 'V': case 'm': case 'o':
1341 /* ??? Before flow, auto inc/dec insns are not supposed to exist,
1342 excepting those that expand_call created. So match memory
1358 /* If an output operand is not a decl or indirect ref and our constraint
1359 allows a register, make a temporary to act as an intermediate.
1360 Make the asm insn write into that, then our caller will copy it to
1361 the real output operand. Likewise for promoted variables. */
1363 if ((TREE_CODE (val) == INDIRECT_REF
1365 || (TREE_CODE_CLASS (TREE_CODE (val)) == 'd'
1366 && (allows_mem || GET_CODE (DECL_RTL (val)) == REG)
1367 && ! (GET_CODE (DECL_RTL (val)) == REG
1368 && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type)))
1373 mark_addressable (TREE_VALUE (tail));
1376 = expand_expr (TREE_VALUE (tail), NULL_RTX, VOIDmode,
1377 EXPAND_MEMORY_USE_WO);
1379 if (! allows_reg && GET_CODE (output_rtx[i]) != MEM)
1380 error ("output number %d not directly addressable", i);
1381 if (! allows_mem && GET_CODE (output_rtx[i]) == MEM)
1382 error ("output number %d not restored to memory", i);
1386 output_rtx[i] = assign_temp (type, 0, 0, 0);
1387 TREE_VALUE (tail) = make_tree (type, output_rtx[i]);
1392 inout_mode[ninout] = TYPE_MODE (TREE_TYPE (TREE_VALUE (tail)));
1393 inout_opnum[ninout++] = i;
1398 if (ninputs + noutputs > MAX_RECOG_OPERANDS)
1400 error ("more than %d operands in `asm'", MAX_RECOG_OPERANDS);
1404 /* Make vectors for the expression-rtx and constraint strings. */
1406 argvec = rtvec_alloc (ninputs);
1407 constraints = rtvec_alloc (ninputs);
1409 body = gen_rtx_ASM_OPERANDS (VOIDmode,
1410 TREE_STRING_POINTER (string), "", 0, argvec,
1411 constraints, filename, line);
1413 MEM_VOLATILE_P (body) = vol;
1415 /* Eval the inputs and put them into ARGVEC.
1416 Put their constraints into ASM_INPUTs and store in CONSTRAINTS. */
1419 for (tail = inputs; tail; tail = TREE_CHAIN (tail))
1422 int allows_reg = 0, allows_mem = 0;
1423 char *constraint, *orig_constraint;
1427 /* If there's an erroneous arg, emit no insn,
1428 because the ASM_INPUT would get VOIDmode
1429 and that could cause a crash in reload. */
1430 if (TREE_TYPE (TREE_VALUE (tail)) == error_mark_node)
1433 /* ??? Can this happen, and does the error message make any sense? */
1434 if (TREE_PURPOSE (tail) == NULL_TREE)
1436 error ("hard register `%s' listed as input operand to `asm'",
1437 TREE_STRING_POINTER (TREE_VALUE (tail)) );
1441 c_len = TREE_STRING_LENGTH (TREE_PURPOSE (tail)) - 1;
1442 constraint = TREE_STRING_POINTER (TREE_PURPOSE (tail));
1443 orig_constraint = constraint;
1445 /* Make sure constraint has neither `=', `+', nor '&'. */
1447 for (j = 0; j < c_len; j++)
1448 switch (constraint[j])
1450 case '+': case '=': case '&':
1451 if (constraint == orig_constraint)
1453 error ("input operand constraint contains `%c'", constraint[j]);
1459 if (constraint == orig_constraint
1460 && i + 1 == ninputs - ninout)
1462 error ("`%%' constraint used with last operand");
1467 case 'V': case 'm': case 'o':
1472 case '?': case '!': case '*':
1473 case 'E': case 'F': case 'G': case 'H': case 'X':
1474 case 's': case 'i': case 'n':
1475 case 'I': case 'J': case 'K': case 'L': case 'M':
1476 case 'N': case 'O': case 'P': case ',':
1477 #ifdef EXTRA_CONSTRAINT
1478 case 'Q': case 'R': case 'S': case 'T': case 'U':
1482 /* Whether or not a numeric constraint allows a register is
1483 decided by the matching constraint, and so there is no need
1484 to do anything special with them. We must handle them in
1485 the default case, so that we don't unnecessarily force
1486 operands to memory. */
1487 case '0': case '1': case '2': case '3': case '4':
1488 case '5': case '6': case '7': case '8': case '9':
1489 if (constraint[j] >= '0' + noutputs)
1492 ("matching constraint references invalid operand number");
1496 /* Try and find the real constraint for this dup. */
1497 if ((j == 0 && c_len == 1)
1498 || (j == 1 && c_len == 2 && constraint[0] == '%'))
1501 for (j = constraint[j] - '0'; j > 0; --j)
1504 c_len = TREE_STRING_LENGTH (TREE_PURPOSE (o)) - 1;
1505 constraint = TREE_STRING_POINTER (TREE_PURPOSE (o));
1510 /* ... fall through ... */
1523 if (! allows_reg && allows_mem)
1524 mark_addressable (TREE_VALUE (tail));
1526 op = expand_expr (TREE_VALUE (tail), NULL_RTX, VOIDmode, 0);
1528 if (asm_operand_ok (op, constraint) <= 0)
1531 op = force_reg (TYPE_MODE (TREE_TYPE (TREE_VALUE (tail))), op);
1532 else if (!allows_mem)
1533 warning ("asm operand %d probably doesn't match constraints", i);
1534 else if (CONSTANT_P (op))
1535 op = force_const_mem (TYPE_MODE (TREE_TYPE (TREE_VALUE (tail))),
1537 else if (GET_CODE (op) == REG
1538 || GET_CODE (op) == SUBREG
1539 || GET_CODE (op) == CONCAT)
1541 tree type = TREE_TYPE (TREE_VALUE (tail));
1542 rtx memloc = assign_temp (type, 1, 1, 1);
1544 emit_move_insn (memloc, op);
1547 else if (GET_CODE (op) == MEM && MEM_VOLATILE_P (op))
1548 /* We won't recognize volatile memory as available a
1549 memory_operand at this point. Ignore it. */
1551 else if (queued_subexp_p (op))
1554 /* ??? Leave this only until we have experience with what
1555 happens in combine and elsewhere when constraints are
1557 warning ("asm operand %d probably doesn't match constraints", i);
1559 XVECEXP (body, 3, i) = op;
1561 XVECEXP (body, 4, i) /* constraints */
1562 = gen_rtx_ASM_INPUT (TYPE_MODE (TREE_TYPE (TREE_VALUE (tail))),
1567 /* Protect all the operands from the queue,
1568 now that they have all been evaluated. */
1570 for (i = 0; i < ninputs - ninout; i++)
1571 XVECEXP (body, 3, i) = protect_from_queue (XVECEXP (body, 3, i), 0);
1573 for (i = 0; i < noutputs; i++)
1574 output_rtx[i] = protect_from_queue (output_rtx[i], 1);
1576 /* For in-out operands, copy output rtx to input rtx. */
1577 for (i = 0; i < ninout; i++)
1579 static char match[9+1][2]
1580 = {"0", "1", "2", "3", "4", "5", "6", "7", "8", "9"};
1581 int j = inout_opnum[i];
1583 XVECEXP (body, 3, ninputs - ninout + i) /* argvec */
1585 XVECEXP (body, 4, ninputs - ninout + i) /* constraints */
1586 = gen_rtx_ASM_INPUT (inout_mode[j], match[j]);
1589 /* Now, for each output, construct an rtx
1590 (set OUTPUT (asm_operands INSN OUTPUTNUMBER OUTPUTCONSTRAINT
1591 ARGVEC CONSTRAINTS))
1592 If there is more than one, put them inside a PARALLEL. */
1594 if (noutputs == 1 && nclobbers == 0)
1596 XSTR (body, 1) = TREE_STRING_POINTER (TREE_PURPOSE (outputs));
1597 insn = emit_insn (gen_rtx_SET (VOIDmode, output_rtx[0], body));
1599 else if (noutputs == 0 && nclobbers == 0)
1601 /* No output operands: put in a raw ASM_OPERANDS rtx. */
1602 insn = emit_insn (body);
1608 if (num == 0) num = 1;
1609 body = gen_rtx_PARALLEL (VOIDmode, rtvec_alloc (num + nclobbers));
1611 /* For each output operand, store a SET. */
1613 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1615 XVECEXP (body, 0, i)
1616 = gen_rtx_SET (VOIDmode,
1618 gen_rtx_ASM_OPERANDS (VOIDmode,
1619 TREE_STRING_POINTER (string),
1620 TREE_STRING_POINTER (TREE_PURPOSE (tail)),
1621 i, argvec, constraints,
1623 MEM_VOLATILE_P (SET_SRC (XVECEXP (body, 0, i))) = vol;
1626 /* If there are no outputs (but there are some clobbers)
1627 store the bare ASM_OPERANDS into the PARALLEL. */
1630 XVECEXP (body, 0, i++) = obody;
1632 /* Store (clobber REG) for each clobbered register specified. */
1634 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1636 char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1637 int j = decode_reg_name (regname);
1641 if (j == -3) /* `cc', which is not a register */
1644 if (j == -4) /* `memory', don't cache memory across asm */
1646 XVECEXP (body, 0, i++)
1647 = gen_rtx_CLOBBER (VOIDmode,
1648 gen_rtx_MEM (BLKmode,
1649 gen_rtx_SCRATCH (VOIDmode)));
1653 /* Ignore unknown register, error already signaled. */
1657 /* Use QImode since that's guaranteed to clobber just one reg. */
1658 XVECEXP (body, 0, i++)
1659 = gen_rtx_CLOBBER (VOIDmode, gen_rtx_REG (QImode, j));
1662 insn = emit_insn (body);
1668 /* Generate RTL to evaluate the expression EXP
1669 and remember it in case this is the VALUE in a ({... VALUE; }) constr. */
1672 expand_expr_stmt (exp)
1675 /* If -W, warn about statements with no side effects,
1676 except for an explicit cast to void (e.g. for assert()), and
1677 except inside a ({...}) where they may be useful. */
1678 if (expr_stmts_for_value == 0 && exp != error_mark_node)
1680 if (! TREE_SIDE_EFFECTS (exp) && (extra_warnings || warn_unused)
1681 && !(TREE_CODE (exp) == CONVERT_EXPR
1682 && TREE_TYPE (exp) == void_type_node))
1683 warning_with_file_and_line (emit_filename, emit_lineno,
1684 "statement with no effect");
1685 else if (warn_unused)
1686 warn_if_unused_value (exp);
1689 /* If EXP is of function type and we are expanding statements for
1690 value, convert it to pointer-to-function. */
1691 if (expr_stmts_for_value && TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE)
1692 exp = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (exp)), exp);
1694 last_expr_type = TREE_TYPE (exp);
1695 last_expr_value = expand_expr (exp,
1696 (expr_stmts_for_value
1697 ? NULL_RTX : const0_rtx),
1700 /* If all we do is reference a volatile value in memory,
1701 copy it to a register to be sure it is actually touched. */
1702 if (last_expr_value != 0 && GET_CODE (last_expr_value) == MEM
1703 && TREE_THIS_VOLATILE (exp))
1705 if (TYPE_MODE (TREE_TYPE (exp)) == VOIDmode)
1707 else if (TYPE_MODE (TREE_TYPE (exp)) != BLKmode)
1708 copy_to_reg (last_expr_value);
1711 rtx lab = gen_label_rtx ();
1713 /* Compare the value with itself to reference it. */
1714 emit_cmp_and_jump_insns (last_expr_value, last_expr_value, EQ,
1715 expand_expr (TYPE_SIZE (last_expr_type),
1716 NULL_RTX, VOIDmode, 0),
1718 TYPE_ALIGN (last_expr_type) / BITS_PER_UNIT,
1724 /* If this expression is part of a ({...}) and is in memory, we may have
1725 to preserve temporaries. */
1726 preserve_temp_slots (last_expr_value);
1728 /* Free any temporaries used to evaluate this expression. Any temporary
1729 used as a result of this expression will already have been preserved
1736 /* Warn if EXP contains any computations whose results are not used.
1737 Return 1 if a warning is printed; 0 otherwise. */
1740 warn_if_unused_value (exp)
1743 if (TREE_USED (exp))
1746 switch (TREE_CODE (exp))
1748 case PREINCREMENT_EXPR:
1749 case POSTINCREMENT_EXPR:
1750 case PREDECREMENT_EXPR:
1751 case POSTDECREMENT_EXPR:
1756 case METHOD_CALL_EXPR:
1758 case TRY_CATCH_EXPR:
1759 case WITH_CLEANUP_EXPR:
1761 /* We don't warn about COND_EXPR because it may be a useful
1762 construct if either arm contains a side effect. */
1767 /* For a binding, warn if no side effect within it. */
1768 return warn_if_unused_value (TREE_OPERAND (exp, 1));
1771 return warn_if_unused_value (TREE_OPERAND (exp, 1));
1773 case TRUTH_ORIF_EXPR:
1774 case TRUTH_ANDIF_EXPR:
1775 /* In && or ||, warn if 2nd operand has no side effect. */
1776 return warn_if_unused_value (TREE_OPERAND (exp, 1));
1779 if (TREE_NO_UNUSED_WARNING (exp))
1781 if (warn_if_unused_value (TREE_OPERAND (exp, 0)))
1783 /* Let people do `(foo (), 0)' without a warning. */
1784 if (TREE_CONSTANT (TREE_OPERAND (exp, 1)))
1786 return warn_if_unused_value (TREE_OPERAND (exp, 1));
1790 case NON_LVALUE_EXPR:
1791 /* Don't warn about values cast to void. */
1792 if (TREE_TYPE (exp) == void_type_node)
1794 /* Don't warn about conversions not explicit in the user's program. */
1795 if (TREE_NO_UNUSED_WARNING (exp))
1797 /* Assignment to a cast usually results in a cast of a modify.
1798 Don't complain about that. There can be an arbitrary number of
1799 casts before the modify, so we must loop until we find the first
1800 non-cast expression and then test to see if that is a modify. */
1802 tree tem = TREE_OPERAND (exp, 0);
1804 while (TREE_CODE (tem) == CONVERT_EXPR || TREE_CODE (tem) == NOP_EXPR)
1805 tem = TREE_OPERAND (tem, 0);
1807 if (TREE_CODE (tem) == MODIFY_EXPR || TREE_CODE (tem) == INIT_EXPR
1808 || TREE_CODE (tem) == CALL_EXPR)
1814 /* Don't warn about automatic dereferencing of references, since
1815 the user cannot control it. */
1816 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (exp, 0))) == REFERENCE_TYPE)
1817 return warn_if_unused_value (TREE_OPERAND (exp, 0));
1818 /* ... fall through ... */
1821 /* Referencing a volatile value is a side effect, so don't warn. */
1822 if ((TREE_CODE_CLASS (TREE_CODE (exp)) == 'd'
1823 || TREE_CODE_CLASS (TREE_CODE (exp)) == 'r')
1824 && TREE_THIS_VOLATILE (exp))
1827 warning_with_file_and_line (emit_filename, emit_lineno,
1828 "value computed is not used");
1833 /* Clear out the memory of the last expression evaluated. */
1841 /* Begin a statement which will return a value.
1842 Return the RTL_EXPR for this statement expr.
1843 The caller must save that value and pass it to expand_end_stmt_expr. */
1846 expand_start_stmt_expr ()
1851 /* Make the RTL_EXPR node temporary, not momentary,
1852 so that rtl_expr_chain doesn't become garbage. */
1853 momentary = suspend_momentary ();
1854 t = make_node (RTL_EXPR);
1855 resume_momentary (momentary);
1856 do_pending_stack_adjust ();
1857 start_sequence_for_rtl_expr (t);
1859 expr_stmts_for_value++;
1863 /* Restore the previous state at the end of a statement that returns a value.
1864 Returns a tree node representing the statement's value and the
1865 insns to compute the value.
1867 The nodes of that expression have been freed by now, so we cannot use them.
1868 But we don't want to do that anyway; the expression has already been
1869 evaluated and now we just want to use the value. So generate a RTL_EXPR
1870 with the proper type and RTL value.
1872 If the last substatement was not an expression,
1873 return something with type `void'. */
1876 expand_end_stmt_expr (t)
1881 if (last_expr_type == 0)
1883 last_expr_type = void_type_node;
1884 last_expr_value = const0_rtx;
1886 else if (last_expr_value == 0)
1887 /* There are some cases where this can happen, such as when the
1888 statement is void type. */
1889 last_expr_value = const0_rtx;
1890 else if (GET_CODE (last_expr_value) != REG && ! CONSTANT_P (last_expr_value))
1891 /* Remove any possible QUEUED. */
1892 last_expr_value = protect_from_queue (last_expr_value, 0);
1896 TREE_TYPE (t) = last_expr_type;
1897 RTL_EXPR_RTL (t) = last_expr_value;
1898 RTL_EXPR_SEQUENCE (t) = get_insns ();
1900 rtl_expr_chain = tree_cons (NULL_TREE, t, rtl_expr_chain);
1904 /* Don't consider deleting this expr or containing exprs at tree level. */
1905 TREE_SIDE_EFFECTS (t) = 1;
1906 /* Propagate volatility of the actual RTL expr. */
1907 TREE_THIS_VOLATILE (t) = volatile_refs_p (last_expr_value);
1910 expr_stmts_for_value--;
1915 /* Generate RTL for the start of an if-then. COND is the expression
1916 whose truth should be tested.
1918 If EXITFLAG is nonzero, this conditional is visible to
1919 `exit_something'. */
1922 expand_start_cond (cond, exitflag)
1926 struct nesting *thiscond = ALLOC_NESTING ();
1928 /* Make an entry on cond_stack for the cond we are entering. */
1930 thiscond->next = cond_stack;
1931 thiscond->all = nesting_stack;
1932 thiscond->depth = ++nesting_depth;
1933 thiscond->data.cond.next_label = gen_label_rtx ();
1934 /* Before we encounter an `else', we don't need a separate exit label
1935 unless there are supposed to be exit statements
1936 to exit this conditional. */
1937 thiscond->exit_label = exitflag ? gen_label_rtx () : 0;
1938 thiscond->data.cond.endif_label = thiscond->exit_label;
1939 cond_stack = thiscond;
1940 nesting_stack = thiscond;
1942 do_jump (cond, thiscond->data.cond.next_label, NULL_RTX);
1945 /* Generate RTL between then-clause and the elseif-clause
1946 of an if-then-elseif-.... */
1949 expand_start_elseif (cond)
1952 if (cond_stack->data.cond.endif_label == 0)
1953 cond_stack->data.cond.endif_label = gen_label_rtx ();
1954 emit_jump (cond_stack->data.cond.endif_label);
1955 emit_label (cond_stack->data.cond.next_label);
1956 cond_stack->data.cond.next_label = gen_label_rtx ();
1957 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
1960 /* Generate RTL between the then-clause and the else-clause
1961 of an if-then-else. */
1964 expand_start_else ()
1966 if (cond_stack->data.cond.endif_label == 0)
1967 cond_stack->data.cond.endif_label = gen_label_rtx ();
1969 emit_jump (cond_stack->data.cond.endif_label);
1970 emit_label (cond_stack->data.cond.next_label);
1971 cond_stack->data.cond.next_label = 0; /* No more _else or _elseif calls. */
1974 /* After calling expand_start_else, turn this "else" into an "else if"
1975 by providing another condition. */
1978 expand_elseif (cond)
1981 cond_stack->data.cond.next_label = gen_label_rtx ();
1982 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
1985 /* Generate RTL for the end of an if-then.
1986 Pop the record for it off of cond_stack. */
1991 struct nesting *thiscond = cond_stack;
1993 do_pending_stack_adjust ();
1994 if (thiscond->data.cond.next_label)
1995 emit_label (thiscond->data.cond.next_label);
1996 if (thiscond->data.cond.endif_label)
1997 emit_label (thiscond->data.cond.endif_label);
1999 POPSTACK (cond_stack);
2005 /* Generate RTL for the start of a loop. EXIT_FLAG is nonzero if this
2006 loop should be exited by `exit_something'. This is a loop for which
2007 `expand_continue' will jump to the top of the loop.
2009 Make an entry on loop_stack to record the labels associated with
2013 expand_start_loop (exit_flag)
2016 register struct nesting *thisloop = ALLOC_NESTING ();
2018 /* Make an entry on loop_stack for the loop we are entering. */
2020 thisloop->next = loop_stack;
2021 thisloop->all = nesting_stack;
2022 thisloop->depth = ++nesting_depth;
2023 thisloop->data.loop.start_label = gen_label_rtx ();
2024 thisloop->data.loop.end_label = gen_label_rtx ();
2025 thisloop->data.loop.alt_end_label = 0;
2026 thisloop->data.loop.continue_label = thisloop->data.loop.start_label;
2027 thisloop->exit_label = exit_flag ? thisloop->data.loop.end_label : 0;
2028 loop_stack = thisloop;
2029 nesting_stack = thisloop;
2031 do_pending_stack_adjust ();
2033 emit_note (NULL_PTR, NOTE_INSN_LOOP_BEG);
2034 emit_label (thisloop->data.loop.start_label);
2039 /* Like expand_start_loop but for a loop where the continuation point
2040 (for expand_continue_loop) will be specified explicitly. */
2043 expand_start_loop_continue_elsewhere (exit_flag)
2046 struct nesting *thisloop = expand_start_loop (exit_flag);
2047 loop_stack->data.loop.continue_label = gen_label_rtx ();
2051 /* Specify the continuation point for a loop started with
2052 expand_start_loop_continue_elsewhere.
2053 Use this at the point in the code to which a continue statement
2057 expand_loop_continue_here ()
2059 do_pending_stack_adjust ();
2060 emit_note (NULL_PTR, NOTE_INSN_LOOP_CONT);
2061 emit_label (loop_stack->data.loop.continue_label);
2064 /* Finish a loop. Generate a jump back to the top and the loop-exit label.
2065 Pop the block off of loop_stack. */
2070 rtx start_label = loop_stack->data.loop.start_label;
2071 rtx insn = get_last_insn ();
2072 int needs_end_jump = 1;
2074 /* Mark the continue-point at the top of the loop if none elsewhere. */
2075 if (start_label == loop_stack->data.loop.continue_label)
2076 emit_note_before (NOTE_INSN_LOOP_CONT, start_label);
2078 do_pending_stack_adjust ();
2080 /* If optimizing, perhaps reorder the loop.
2081 First, try to use a condjump near the end.
2082 expand_exit_loop_if_false ends loops with unconditional jumps,
2085 if (test) goto label;
2087 goto loop_stack->data.loop.end_label
2091 If we find such a pattern, we can end the loop earlier. */
2094 && GET_CODE (insn) == CODE_LABEL
2095 && LABEL_NAME (insn) == NULL
2096 && GET_CODE (PREV_INSN (insn)) == BARRIER)
2099 rtx jump = PREV_INSN (PREV_INSN (label));
2101 if (GET_CODE (jump) == JUMP_INSN
2102 && GET_CODE (PATTERN (jump)) == SET
2103 && SET_DEST (PATTERN (jump)) == pc_rtx
2104 && GET_CODE (SET_SRC (PATTERN (jump))) == LABEL_REF
2105 && (XEXP (SET_SRC (PATTERN (jump)), 0)
2106 == loop_stack->data.loop.end_label))
2110 /* The test might be complex and reference LABEL multiple times,
2111 like the loop in loop_iterations to set vtop. To handle this,
2113 insn = PREV_INSN (label);
2114 reorder_insns (label, label, start_label);
2116 for (prev = PREV_INSN (jump); ; prev = PREV_INSN (prev))
2118 /* We ignore line number notes, but if we see any other note,
2119 in particular NOTE_INSN_BLOCK_*, NOTE_INSN_EH_REGION_*,
2120 NOTE_INSN_LOOP_*, we disable this optimization. */
2121 if (GET_CODE (prev) == NOTE)
2123 if (NOTE_LINE_NUMBER (prev) < 0)
2127 if (GET_CODE (prev) == CODE_LABEL)
2129 if (GET_CODE (prev) == JUMP_INSN)
2131 if (GET_CODE (PATTERN (prev)) == SET
2132 && SET_DEST (PATTERN (prev)) == pc_rtx
2133 && GET_CODE (SET_SRC (PATTERN (prev))) == IF_THEN_ELSE
2134 && (GET_CODE (XEXP (SET_SRC (PATTERN (prev)), 1))
2136 && XEXP (XEXP (SET_SRC (PATTERN (prev)), 1), 0) == label)
2138 XEXP (XEXP (SET_SRC (PATTERN (prev)), 1), 0)
2140 emit_note_after (NOTE_INSN_LOOP_END, prev);
2149 /* If the loop starts with a loop exit, roll that to the end where
2150 it will optimize together with the jump back.
2152 We look for the conditional branch to the exit, except that once
2153 we find such a branch, we don't look past 30 instructions.
2155 In more detail, if the loop presently looks like this (in pseudo-C):
2158 if (test) goto end_label;
2163 transform it to look like:
2169 if (test) goto end_label;
2170 goto newstart_label;
2173 Here, the `test' may actually consist of some reasonably complex
2174 code, terminating in a test. */
2179 ! (GET_CODE (insn) == JUMP_INSN
2180 && GET_CODE (PATTERN (insn)) == SET
2181 && SET_DEST (PATTERN (insn)) == pc_rtx
2182 && GET_CODE (SET_SRC (PATTERN (insn))) == IF_THEN_ELSE))
2186 rtx last_test_insn = NULL_RTX;
2188 /* Scan insns from the top of the loop looking for a qualified
2189 conditional exit. */
2190 for (insn = NEXT_INSN (loop_stack->data.loop.start_label); insn;
2191 insn = NEXT_INSN (insn))
2193 if (GET_CODE (insn) == NOTE)
2196 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
2197 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
2198 /* The code that actually moves the exit test will
2199 carefully leave BLOCK notes in their original
2200 location. That means, however, that we can't debug
2201 the exit test itself. So, we refuse to move code
2202 containing BLOCK notes at low optimization levels. */
2205 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG)
2207 else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END)
2211 /* We've come to the end of an EH region, but
2212 never saw the beginning of that region. That
2213 means that an EH region begins before the top
2214 of the loop, and ends in the middle of it. The
2215 existence of such a situation violates a basic
2216 assumption in this code, since that would imply
2217 that even when EH_REGIONS is zero, we might
2218 move code out of an exception region. */
2222 /* We must not walk into a nested loop. */
2223 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)
2226 /* We already know this INSN is a NOTE, so there's no
2227 point in looking at it to see if it's a JUMP. */
2231 if (GET_CODE (insn) == JUMP_INSN || GET_CODE (insn) == INSN)
2234 if (last_test_insn && num_insns > 30)
2238 /* We don't want to move a partial EH region. Consider:
2252 This isn't legal C++, but here's what it's supposed to
2253 mean: if cond() is true, stop looping. Otherwise,
2254 call bar, and keep looping. In addition, if cond
2255 throws an exception, catch it and keep looping. Such
2256 constructs are certainy legal in LISP.
2258 We should not move the `if (cond()) 0' test since then
2259 the EH-region for the try-block would be broken up.
2260 (In this case we would the EH_BEG note for the `try'
2261 and `if cond()' but not the call to bar() or the
2264 So we don't look for tests within an EH region. */
2267 if (GET_CODE (insn) == JUMP_INSN
2268 && GET_CODE (PATTERN (insn)) == SET
2269 && SET_DEST (PATTERN (insn)) == pc_rtx)
2271 /* This is indeed a jump. */
2272 rtx dest1 = NULL_RTX;
2273 rtx dest2 = NULL_RTX;
2274 rtx potential_last_test;
2275 if (GET_CODE (SET_SRC (PATTERN (insn))) == IF_THEN_ELSE)
2277 /* A conditional jump. */
2278 dest1 = XEXP (SET_SRC (PATTERN (insn)), 1);
2279 dest2 = XEXP (SET_SRC (PATTERN (insn)), 2);
2280 potential_last_test = insn;
2284 /* An unconditional jump. */
2285 dest1 = SET_SRC (PATTERN (insn));
2286 /* Include the BARRIER after the JUMP. */
2287 potential_last_test = NEXT_INSN (insn);
2291 if (dest1 && GET_CODE (dest1) == LABEL_REF
2292 && ((XEXP (dest1, 0)
2293 == loop_stack->data.loop.alt_end_label)
2295 == loop_stack->data.loop.end_label)))
2297 last_test_insn = potential_last_test;
2301 /* If this was a conditional jump, there may be
2302 another label at which we should look. */
2309 if (last_test_insn != 0 && last_test_insn != get_last_insn ())
2311 /* We found one. Move everything from there up
2312 to the end of the loop, and add a jump into the loop
2313 to jump to there. */
2314 register rtx newstart_label = gen_label_rtx ();
2315 register rtx start_move = start_label;
2318 /* If the start label is preceded by a NOTE_INSN_LOOP_CONT note,
2319 then we want to move this note also. */
2320 if (GET_CODE (PREV_INSN (start_move)) == NOTE
2321 && (NOTE_LINE_NUMBER (PREV_INSN (start_move))
2322 == NOTE_INSN_LOOP_CONT))
2323 start_move = PREV_INSN (start_move);
2325 emit_label_after (newstart_label, PREV_INSN (start_move));
2327 /* Actually move the insns. Start at the beginning, and
2328 keep copying insns until we've copied the
2330 for (insn = start_move; insn; insn = next_insn)
2332 /* Figure out which insn comes after this one. We have
2333 to do this before we move INSN. */
2334 if (insn == last_test_insn)
2335 /* We've moved all the insns. */
2336 next_insn = NULL_RTX;
2338 next_insn = NEXT_INSN (insn);
2340 if (GET_CODE (insn) == NOTE
2341 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
2342 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
2343 /* We don't want to move NOTE_INSN_BLOCK_BEGs or
2344 NOTE_INSN_BLOCK_ENDs because the correct generation
2345 of debugging information depends on these appearing
2346 in the same order in the RTL and in the tree
2347 structure, where they are represented as BLOCKs.
2348 So, we don't move block notes. Of course, moving
2349 the code inside the block is likely to make it
2350 impossible to debug the instructions in the exit
2351 test, but such is the price of optimization. */
2354 /* Move the INSN. */
2355 reorder_insns (insn, insn, get_last_insn ());
2358 emit_jump_insn_after (gen_jump (start_label),
2359 PREV_INSN (newstart_label));
2360 emit_barrier_after (PREV_INSN (newstart_label));
2361 start_label = newstart_label;
2367 emit_jump (start_label);
2368 emit_note (NULL_PTR, NOTE_INSN_LOOP_END);
2370 emit_label (loop_stack->data.loop.end_label);
2372 POPSTACK (loop_stack);
2377 /* Generate a jump to the current loop's continue-point.
2378 This is usually the top of the loop, but may be specified
2379 explicitly elsewhere. If not currently inside a loop,
2380 return 0 and do nothing; caller will print an error message. */
2383 expand_continue_loop (whichloop)
2384 struct nesting *whichloop;
2388 whichloop = loop_stack;
2391 expand_goto_internal (NULL_TREE, whichloop->data.loop.continue_label,
2396 /* Generate a jump to exit the current loop. If not currently inside a loop,
2397 return 0 and do nothing; caller will print an error message. */
2400 expand_exit_loop (whichloop)
2401 struct nesting *whichloop;
2405 whichloop = loop_stack;
2408 expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label, NULL_RTX);
2412 /* Generate a conditional jump to exit the current loop if COND
2413 evaluates to zero. If not currently inside a loop,
2414 return 0 and do nothing; caller will print an error message. */
2417 expand_exit_loop_if_false (whichloop, cond)
2418 struct nesting *whichloop;
2421 rtx label = gen_label_rtx ();
2426 whichloop = loop_stack;
2429 /* In order to handle fixups, we actually create a conditional jump
2430 around a unconditional branch to exit the loop. If fixups are
2431 necessary, they go before the unconditional branch. */
2434 do_jump (cond, NULL_RTX, label);
2435 last_insn = get_last_insn ();
2436 if (GET_CODE (last_insn) == CODE_LABEL)
2437 whichloop->data.loop.alt_end_label = last_insn;
2438 expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label,
2445 /* Return nonzero if the loop nest is empty. Else return zero. */
2448 stmt_loop_nest_empty ()
2450 return (loop_stack == NULL);
2453 /* Return non-zero if we should preserve sub-expressions as separate
2454 pseudos. We never do so if we aren't optimizing. We always do so
2455 if -fexpensive-optimizations.
2457 Otherwise, we only do so if we are in the "early" part of a loop. I.e.,
2458 the loop may still be a small one. */
2461 preserve_subexpressions_p ()
2465 if (flag_expensive_optimizations)
2468 if (optimize == 0 || loop_stack == 0)
2471 insn = get_last_insn_anywhere ();
2474 && (INSN_UID (insn) - INSN_UID (loop_stack->data.loop.start_label)
2475 < n_non_fixed_regs * 3));
2479 /* Generate a jump to exit the current loop, conditional, binding contour
2480 or case statement. Not all such constructs are visible to this function,
2481 only those started with EXIT_FLAG nonzero. Individual languages use
2482 the EXIT_FLAG parameter to control which kinds of constructs you can
2485 If not currently inside anything that can be exited,
2486 return 0 and do nothing; caller will print an error message. */
2489 expand_exit_something ()
2493 for (n = nesting_stack; n; n = n->all)
2494 if (n->exit_label != 0)
2496 expand_goto_internal (NULL_TREE, n->exit_label, NULL_RTX);
2503 /* Generate RTL to return from the current function, with no value.
2504 (That is, we do not do anything about returning any value.) */
2507 expand_null_return ()
2509 struct nesting *block = block_stack;
2512 /* Does any pending block have cleanups? */
2514 while (block && block->data.block.cleanups == 0)
2515 block = block->next;
2517 /* If yes, use a goto to return, since that runs cleanups. */
2519 expand_null_return_1 (last_insn, block != 0);
2522 /* Generate RTL to return from the current function, with value VAL. */
2525 expand_value_return (val)
2528 struct nesting *block = block_stack;
2529 rtx last_insn = get_last_insn ();
2530 rtx return_reg = DECL_RTL (DECL_RESULT (current_function_decl));
2532 /* Copy the value to the return location
2533 unless it's already there. */
2535 if (return_reg != val)
2537 #ifdef PROMOTE_FUNCTION_RETURN
2538 tree type = TREE_TYPE (DECL_RESULT (current_function_decl));
2539 int unsignedp = TREE_UNSIGNED (type);
2540 enum machine_mode mode
2541 = promote_mode (type, DECL_MODE (DECL_RESULT (current_function_decl)),
2544 if (GET_MODE (val) != VOIDmode && GET_MODE (val) != mode)
2545 convert_move (return_reg, val, unsignedp);
2548 emit_move_insn (return_reg, val);
2550 if (GET_CODE (return_reg) == REG
2551 && REGNO (return_reg) < FIRST_PSEUDO_REGISTER)
2552 emit_insn (gen_rtx_USE (VOIDmode, return_reg));
2553 /* Handle calls that return values in multiple non-contiguous locations.
2554 The Irix 6 ABI has examples of this. */
2555 else if (GET_CODE (return_reg) == PARALLEL)
2559 for (i = 0; i < XVECLEN (return_reg, 0); i++)
2561 rtx x = XEXP (XVECEXP (return_reg, 0, i), 0);
2563 if (GET_CODE (x) == REG
2564 && REGNO (x) < FIRST_PSEUDO_REGISTER)
2565 emit_insn (gen_rtx_USE (VOIDmode, x));
2569 /* Does any pending block have cleanups? */
2571 while (block && block->data.block.cleanups == 0)
2572 block = block->next;
2574 /* If yes, use a goto to return, since that runs cleanups.
2575 Use LAST_INSN to put cleanups *before* the move insn emitted above. */
2577 expand_null_return_1 (last_insn, block != 0);
2580 /* Output a return with no value. If LAST_INSN is nonzero,
2581 pretend that the return takes place after LAST_INSN.
2582 If USE_GOTO is nonzero then don't use a return instruction;
2583 go to the return label instead. This causes any cleanups
2584 of pending blocks to be executed normally. */
2587 expand_null_return_1 (last_insn, use_goto)
2591 rtx end_label = cleanup_label ? cleanup_label : return_label;
2593 clear_pending_stack_adjust ();
2594 do_pending_stack_adjust ();
2597 /* PCC-struct return always uses an epilogue. */
2598 if (current_function_returns_pcc_struct || use_goto)
2601 end_label = return_label = gen_label_rtx ();
2602 expand_goto_internal (NULL_TREE, end_label, last_insn);
2606 /* Otherwise output a simple return-insn if one is available,
2607 unless it won't do the job. */
2609 if (HAVE_return && use_goto == 0 && cleanup_label == 0)
2611 emit_jump_insn (gen_return ());
2617 /* Otherwise jump to the epilogue. */
2618 expand_goto_internal (NULL_TREE, end_label, last_insn);
2621 /* Generate RTL to evaluate the expression RETVAL and return it
2622 from the current function. */
2625 expand_return (retval)
2628 /* If there are any cleanups to be performed, then they will
2629 be inserted following LAST_INSN. It is desirable
2630 that the last_insn, for such purposes, should be the
2631 last insn before computing the return value. Otherwise, cleanups
2632 which call functions can clobber the return value. */
2633 /* ??? rms: I think that is erroneous, because in C++ it would
2634 run destructors on variables that might be used in the subsequent
2635 computation of the return value. */
2637 register rtx val = 0;
2642 /* If function wants no value, give it none. */
2643 if (TREE_CODE (TREE_TYPE (TREE_TYPE (current_function_decl))) == VOID_TYPE)
2645 expand_expr (retval, NULL_RTX, VOIDmode, 0);
2647 expand_null_return ();
2651 /* Are any cleanups needed? E.g. C++ destructors to be run? */
2652 /* This is not sufficient. We also need to watch for cleanups of the
2653 expression we are about to expand. Unfortunately, we cannot know
2654 if it has cleanups until we expand it, and we want to change how we
2655 expand it depending upon if we need cleanups. We can't win. */
2657 cleanups = any_pending_cleanups (1);
2662 if (TREE_CODE (retval) == RESULT_DECL)
2663 retval_rhs = retval;
2664 else if ((TREE_CODE (retval) == MODIFY_EXPR || TREE_CODE (retval) == INIT_EXPR)
2665 && TREE_CODE (TREE_OPERAND (retval, 0)) == RESULT_DECL)
2666 retval_rhs = TREE_OPERAND (retval, 1);
2667 else if (TREE_TYPE (retval) == void_type_node)
2668 /* Recognize tail-recursive call to void function. */
2669 retval_rhs = retval;
2671 retval_rhs = NULL_TREE;
2673 /* Only use `last_insn' if there are cleanups which must be run. */
2674 if (cleanups || cleanup_label != 0)
2675 last_insn = get_last_insn ();
2677 /* Distribute return down conditional expr if either of the sides
2678 may involve tail recursion (see test below). This enhances the number
2679 of tail recursions we see. Don't do this always since it can produce
2680 sub-optimal code in some cases and we distribute assignments into
2681 conditional expressions when it would help. */
2683 if (optimize && retval_rhs != 0
2684 && frame_offset == 0
2685 && TREE_CODE (retval_rhs) == COND_EXPR
2686 && (TREE_CODE (TREE_OPERAND (retval_rhs, 1)) == CALL_EXPR
2687 || TREE_CODE (TREE_OPERAND (retval_rhs, 2)) == CALL_EXPR))
2689 rtx label = gen_label_rtx ();
2692 do_jump (TREE_OPERAND (retval_rhs, 0), label, NULL_RTX);
2693 expr = build (MODIFY_EXPR, TREE_TYPE (TREE_TYPE (current_function_decl)),
2694 DECL_RESULT (current_function_decl),
2695 TREE_OPERAND (retval_rhs, 1));
2696 TREE_SIDE_EFFECTS (expr) = 1;
2697 expand_return (expr);
2700 expr = build (MODIFY_EXPR, TREE_TYPE (TREE_TYPE (current_function_decl)),
2701 DECL_RESULT (current_function_decl),
2702 TREE_OPERAND (retval_rhs, 2));
2703 TREE_SIDE_EFFECTS (expr) = 1;
2704 expand_return (expr);
2708 /* Attempt to optimize the call if it is tail recursive. */
2709 if (optimize_tail_recursion (retval_rhs, last_insn))
2713 /* This optimization is safe if there are local cleanups
2714 because expand_null_return takes care of them.
2715 ??? I think it should also be safe when there is a cleanup label,
2716 because expand_null_return takes care of them, too.
2717 Any reason why not? */
2718 if (HAVE_return && cleanup_label == 0
2719 && ! current_function_returns_pcc_struct
2720 && BRANCH_COST <= 1)
2722 /* If this is return x == y; then generate
2723 if (x == y) return 1; else return 0;
2724 if we can do it with explicit return insns and branches are cheap,
2725 but not if we have the corresponding scc insn. */
2728 switch (TREE_CODE (retval_rhs))
2754 case TRUTH_ANDIF_EXPR:
2755 case TRUTH_ORIF_EXPR:
2756 case TRUTH_AND_EXPR:
2758 case TRUTH_NOT_EXPR:
2759 case TRUTH_XOR_EXPR:
2762 op0 = gen_label_rtx ();
2763 jumpifnot (retval_rhs, op0);
2764 expand_value_return (const1_rtx);
2766 expand_value_return (const0_rtx);
2775 #endif /* HAVE_return */
2777 /* If the result is an aggregate that is being returned in one (or more)
2778 registers, load the registers here. The compiler currently can't handle
2779 copying a BLKmode value into registers. We could put this code in a
2780 more general area (for use by everyone instead of just function
2781 call/return), but until this feature is generally usable it is kept here
2782 (and in expand_call). The value must go into a pseudo in case there
2783 are cleanups that will clobber the real return register. */
2786 && TYPE_MODE (TREE_TYPE (retval_rhs)) == BLKmode
2787 && GET_CODE (DECL_RTL (DECL_RESULT (current_function_decl))) == REG)
2789 int i, bitpos, xbitpos;
2790 int big_endian_correction = 0;
2791 int bytes = int_size_in_bytes (TREE_TYPE (retval_rhs));
2792 int n_regs = (bytes + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
2793 int bitsize = MIN (TYPE_ALIGN (TREE_TYPE (retval_rhs)),
2794 (unsigned int)BITS_PER_WORD);
2795 rtx *result_pseudos = (rtx *) alloca (sizeof (rtx) * n_regs);
2796 rtx result_reg, src = NULL_RTX, dst = NULL_RTX;
2797 rtx result_val = expand_expr (retval_rhs, NULL_RTX, VOIDmode, 0);
2798 enum machine_mode tmpmode, result_reg_mode;
2800 /* Structures whose size is not a multiple of a word are aligned
2801 to the least significant byte (to the right). On a BYTES_BIG_ENDIAN
2802 machine, this means we must skip the empty high order bytes when
2803 calculating the bit offset. */
2804 if (BYTES_BIG_ENDIAN && bytes % UNITS_PER_WORD)
2805 big_endian_correction = (BITS_PER_WORD - ((bytes % UNITS_PER_WORD)
2808 /* Copy the structure BITSIZE bits at a time. */
2809 for (bitpos = 0, xbitpos = big_endian_correction;
2810 bitpos < bytes * BITS_PER_UNIT;
2811 bitpos += bitsize, xbitpos += bitsize)
2813 /* We need a new destination pseudo each time xbitpos is
2814 on a word boundary and when xbitpos == big_endian_correction
2815 (the first time through). */
2816 if (xbitpos % BITS_PER_WORD == 0
2817 || xbitpos == big_endian_correction)
2819 /* Generate an appropriate register. */
2820 dst = gen_reg_rtx (word_mode);
2821 result_pseudos[xbitpos / BITS_PER_WORD] = dst;
2823 /* Clobber the destination before we move anything into it. */
2824 emit_insn (gen_rtx_CLOBBER (VOIDmode, dst));
2827 /* We need a new source operand each time bitpos is on a word
2829 if (bitpos % BITS_PER_WORD == 0)
2830 src = operand_subword_force (result_val,
2831 bitpos / BITS_PER_WORD,
2834 /* Use bitpos for the source extraction (left justified) and
2835 xbitpos for the destination store (right justified). */
2836 store_bit_field (dst, bitsize, xbitpos % BITS_PER_WORD, word_mode,
2837 extract_bit_field (src, bitsize,
2838 bitpos % BITS_PER_WORD, 1,
2839 NULL_RTX, word_mode,
2841 bitsize / BITS_PER_UNIT,
2843 bitsize / BITS_PER_UNIT, BITS_PER_WORD);
2846 /* Find the smallest integer mode large enough to hold the
2847 entire structure and use that mode instead of BLKmode
2848 on the USE insn for the return register. */
2849 bytes = int_size_in_bytes (TREE_TYPE (retval_rhs));
2850 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
2851 tmpmode != MAX_MACHINE_MODE;
2852 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
2854 /* Have we found a large enough mode? */
2855 if (GET_MODE_SIZE (tmpmode) >= bytes)
2859 /* No suitable mode found. */
2860 if (tmpmode == MAX_MACHINE_MODE)
2863 PUT_MODE (DECL_RTL (DECL_RESULT (current_function_decl)), tmpmode);
2865 if (GET_MODE_SIZE (tmpmode) < GET_MODE_SIZE (word_mode))
2866 result_reg_mode = word_mode;
2868 result_reg_mode = tmpmode;
2869 result_reg = gen_reg_rtx (result_reg_mode);
2872 for (i = 0; i < n_regs; i++)
2873 emit_move_insn (operand_subword (result_reg, i, 0, result_reg_mode),
2876 if (tmpmode != result_reg_mode)
2877 result_reg = gen_lowpart (tmpmode, result_reg);
2879 expand_value_return (result_reg);
2883 && TREE_TYPE (retval_rhs) != void_type_node
2884 && GET_CODE (DECL_RTL (DECL_RESULT (current_function_decl))) == REG)
2886 /* Calculate the return value into a pseudo reg. */
2887 val = gen_reg_rtx (DECL_MODE (DECL_RESULT (current_function_decl)));
2888 val = expand_expr (retval_rhs, val, GET_MODE (val), 0);
2889 val = force_not_mem (val);
2891 /* Return the calculated value, doing cleanups first. */
2892 expand_value_return (val);
2896 /* No cleanups or no hard reg used;
2897 calculate value into hard return reg. */
2898 expand_expr (retval, const0_rtx, VOIDmode, 0);
2900 expand_value_return (DECL_RTL (DECL_RESULT (current_function_decl)));
2904 /* Return 1 if the end of the generated RTX is not a barrier.
2905 This means code already compiled can drop through. */
2908 drop_through_at_end_p ()
2910 rtx insn = get_last_insn ();
2911 while (insn && GET_CODE (insn) == NOTE)
2912 insn = PREV_INSN (insn);
2913 return insn && GET_CODE (insn) != BARRIER;
2916 /* Test CALL_EXPR to determine if it is a potential tail recursion call
2917 and emit code to optimize the tail recursion. LAST_INSN indicates where
2918 to place the jump to the tail recursion label. Return TRUE if the
2919 call was optimized into a goto.
2921 This is only used by expand_return, but expand_call is expected to
2925 optimize_tail_recursion (call_expr, last_insn)
2929 /* For tail-recursive call to current function,
2930 just jump back to the beginning.
2931 It's unsafe if any auto variable in this function
2932 has its address taken; for simplicity,
2933 require stack frame to be empty. */
2934 if (optimize && call_expr != 0
2935 && frame_offset == 0
2936 && TREE_CODE (call_expr) == CALL_EXPR
2937 && TREE_CODE (TREE_OPERAND (call_expr, 0)) == ADDR_EXPR
2938 && TREE_OPERAND (TREE_OPERAND (call_expr, 0), 0) == current_function_decl
2939 /* Finish checking validity, and if valid emit code
2940 to set the argument variables for the new call. */
2941 && tail_recursion_args (TREE_OPERAND (call_expr, 1),
2942 DECL_ARGUMENTS (current_function_decl)))
2944 if (tail_recursion_label == 0)
2946 tail_recursion_label = gen_label_rtx ();
2947 emit_label_after (tail_recursion_label,
2948 tail_recursion_reentry);
2951 expand_goto_internal (NULL_TREE, tail_recursion_label, last_insn);
2959 /* Emit code to alter this function's formal parms for a tail-recursive call.
2960 ACTUALS is a list of actual parameter expressions (chain of TREE_LISTs).
2961 FORMALS is the chain of decls of formals.
2962 Return 1 if this can be done;
2963 otherwise return 0 and do not emit any code. */
2966 tail_recursion_args (actuals, formals)
2967 tree actuals, formals;
2969 register tree a = actuals, f = formals;
2971 register rtx *argvec;
2973 /* Check that number and types of actuals are compatible
2974 with the formals. This is not always true in valid C code.
2975 Also check that no formal needs to be addressable
2976 and that all formals are scalars. */
2978 /* Also count the args. */
2980 for (a = actuals, f = formals, i = 0; a && f; a = TREE_CHAIN (a), f = TREE_CHAIN (f), i++)
2982 if (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_VALUE (a)))
2983 != TYPE_MAIN_VARIANT (TREE_TYPE (f)))
2985 if (GET_CODE (DECL_RTL (f)) != REG || DECL_MODE (f) == BLKmode)
2988 if (a != 0 || f != 0)
2991 /* Compute all the actuals. */
2993 argvec = (rtx *) alloca (i * sizeof (rtx));
2995 for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
2996 argvec[i] = expand_expr (TREE_VALUE (a), NULL_RTX, VOIDmode, 0);
2998 /* Find which actual values refer to current values of previous formals.
2999 Copy each of them now, before any formal is changed. */
3001 for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
3005 for (f = formals, j = 0; j < i; f = TREE_CHAIN (f), j++)
3006 if (reg_mentioned_p (DECL_RTL (f), argvec[i]))
3007 { copy = 1; break; }
3009 argvec[i] = copy_to_reg (argvec[i]);
3012 /* Store the values of the actuals into the formals. */
3014 for (f = formals, a = actuals, i = 0; f;
3015 f = TREE_CHAIN (f), a = TREE_CHAIN (a), i++)
3017 if (GET_MODE (DECL_RTL (f)) == GET_MODE (argvec[i]))
3018 emit_move_insn (DECL_RTL (f), argvec[i]);
3020 convert_move (DECL_RTL (f), argvec[i],
3021 TREE_UNSIGNED (TREE_TYPE (TREE_VALUE (a))));
3028 /* Generate the RTL code for entering a binding contour.
3029 The variables are declared one by one, by calls to `expand_decl'.
3031 EXIT_FLAG is nonzero if this construct should be visible to
3032 `exit_something'. */
3035 expand_start_bindings (exit_flag)
3038 struct nesting *thisblock = ALLOC_NESTING ();
3039 rtx note = emit_note (NULL_PTR, NOTE_INSN_BLOCK_BEG);
3041 /* Make an entry on block_stack for the block we are entering. */
3043 thisblock->next = block_stack;
3044 thisblock->all = nesting_stack;
3045 thisblock->depth = ++nesting_depth;
3046 thisblock->data.block.stack_level = 0;
3047 thisblock->data.block.cleanups = 0;
3048 thisblock->data.block.function_call_count = 0;
3049 thisblock->data.block.exception_region = 0;
3050 thisblock->data.block.target_temp_slot_level = target_temp_slot_level;
3052 thisblock->data.block.conditional_code = 0;
3053 thisblock->data.block.last_unconditional_cleanup = note;
3054 thisblock->data.block.cleanup_ptr = &thisblock->data.block.cleanups;
3057 && !(block_stack->data.block.cleanups == NULL_TREE
3058 && block_stack->data.block.outer_cleanups == NULL_TREE))
3059 thisblock->data.block.outer_cleanups
3060 = tree_cons (NULL_TREE, block_stack->data.block.cleanups,
3061 block_stack->data.block.outer_cleanups);
3063 thisblock->data.block.outer_cleanups = 0;
3064 thisblock->data.block.label_chain = 0;
3065 thisblock->data.block.innermost_stack_block = stack_block_stack;
3066 thisblock->data.block.first_insn = note;
3067 thisblock->data.block.block_start_count = ++block_start_count;
3068 thisblock->exit_label = exit_flag ? gen_label_rtx () : 0;
3069 block_stack = thisblock;
3070 nesting_stack = thisblock;
3072 /* Make a new level for allocating stack slots. */
3076 /* Specify the scope of temporaries created by TARGET_EXPRs. Similar
3077 to CLEANUP_POINT_EXPR, but handles cases when a series of calls to
3078 expand_expr are made. After we end the region, we know that all
3079 space for all temporaries that were created by TARGET_EXPRs will be
3080 destroyed and their space freed for reuse. */
3083 expand_start_target_temps ()
3085 /* This is so that even if the result is preserved, the space
3086 allocated will be freed, as we know that it is no longer in use. */
3089 /* Start a new binding layer that will keep track of all cleanup
3090 actions to be performed. */
3091 expand_start_bindings (0);
3093 target_temp_slot_level = temp_slot_level;
3097 expand_end_target_temps ()
3099 expand_end_bindings (NULL_TREE, 0, 0);
3101 /* This is so that even if the result is preserved, the space
3102 allocated will be freed, as we know that it is no longer in use. */
3106 /* Mark top block of block_stack as an implicit binding for an
3107 exception region. This is used to prevent infinite recursion when
3108 ending a binding with expand_end_bindings. It is only ever called
3109 by expand_eh_region_start, as that it the only way to create a
3110 block stack for a exception region. */
3113 mark_block_as_eh_region ()
3115 block_stack->data.block.exception_region = 1;
3116 if (block_stack->next
3117 && block_stack->next->data.block.conditional_code)
3119 block_stack->data.block.conditional_code
3120 = block_stack->next->data.block.conditional_code;
3121 block_stack->data.block.last_unconditional_cleanup
3122 = block_stack->next->data.block.last_unconditional_cleanup;
3123 block_stack->data.block.cleanup_ptr
3124 = block_stack->next->data.block.cleanup_ptr;
3128 /* True if we are currently emitting insns in an area of output code
3129 that is controlled by a conditional expression. This is used by
3130 the cleanup handling code to generate conditional cleanup actions. */
3133 conditional_context ()
3135 return block_stack && block_stack->data.block.conditional_code;
3138 /* Mark top block of block_stack as not for an implicit binding for an
3139 exception region. This is only ever done by expand_eh_region_end
3140 to let expand_end_bindings know that it is being called explicitly
3141 to end the binding layer for just the binding layer associated with
3142 the exception region, otherwise expand_end_bindings would try and
3143 end all implicit binding layers for exceptions regions, and then
3144 one normal binding layer. */
3147 mark_block_as_not_eh_region ()
3149 block_stack->data.block.exception_region = 0;
3152 /* True if the top block of block_stack was marked as for an exception
3153 region by mark_block_as_eh_region. */
3158 return block_stack && block_stack->data.block.exception_region;
3161 /* Given a pointer to a BLOCK node, save a pointer to the most recently
3162 generated NOTE_INSN_BLOCK_END in the BLOCK_END_NOTE field of the given
3166 remember_end_note (block)
3167 register tree block;
3169 BLOCK_END_NOTE (block) = last_block_end_note;
3170 last_block_end_note = NULL_RTX;
3173 /* Emit a handler label for a nonlocal goto handler.
3174 Also emit code to store the handler label in SLOT before BEFORE_INSN. */
3177 expand_nl_handler_label (slot, before_insn)
3178 rtx slot, before_insn;
3181 rtx handler_label = gen_label_rtx ();
3183 /* Don't let jump_optimize delete the handler. */
3184 LABEL_PRESERVE_P (handler_label) = 1;
3187 emit_move_insn (slot, gen_rtx_LABEL_REF (Pmode, handler_label));
3188 insns = get_insns ();
3190 emit_insns_before (insns, before_insn);
3192 emit_label (handler_label);
3194 return handler_label;
3197 /* Emit code to restore vital registers at the beginning of a nonlocal goto
3200 expand_nl_goto_receiver ()
3202 #ifdef HAVE_nonlocal_goto
3203 if (! HAVE_nonlocal_goto)
3205 /* First adjust our frame pointer to its actual value. It was
3206 previously set to the start of the virtual area corresponding to
3207 the stacked variables when we branched here and now needs to be
3208 adjusted to the actual hardware fp value.
3210 Assignments are to virtual registers are converted by
3211 instantiate_virtual_regs into the corresponding assignment
3212 to the underlying register (fp in this case) that makes
3213 the original assignment true.
3214 So the following insn will actually be
3215 decrementing fp by STARTING_FRAME_OFFSET. */
3216 emit_move_insn (virtual_stack_vars_rtx, hard_frame_pointer_rtx);
3218 #if ARG_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3219 if (fixed_regs[ARG_POINTER_REGNUM])
3221 #ifdef ELIMINABLE_REGS
3222 /* If the argument pointer can be eliminated in favor of the
3223 frame pointer, we don't need to restore it. We assume here
3224 that if such an elimination is present, it can always be used.
3225 This is the case on all known machines; if we don't make this
3226 assumption, we do unnecessary saving on many machines. */
3227 static struct elims {int from, to;} elim_regs[] = ELIMINABLE_REGS;
3230 for (i = 0; i < sizeof elim_regs / sizeof elim_regs[0]; i++)
3231 if (elim_regs[i].from == ARG_POINTER_REGNUM
3232 && elim_regs[i].to == HARD_FRAME_POINTER_REGNUM)
3235 if (i == sizeof elim_regs / sizeof elim_regs [0])
3238 /* Now restore our arg pointer from the address at which it
3239 was saved in our stack frame.
3240 If there hasn't be space allocated for it yet, make
3242 if (arg_pointer_save_area == 0)
3243 arg_pointer_save_area
3244 = assign_stack_local (Pmode, GET_MODE_SIZE (Pmode), 0);
3245 emit_move_insn (virtual_incoming_args_rtx,
3246 /* We need a pseudo here, or else
3247 instantiate_virtual_regs_1 complains. */
3248 copy_to_reg (arg_pointer_save_area));
3253 #ifdef HAVE_nonlocal_goto_receiver
3254 if (HAVE_nonlocal_goto_receiver)
3255 emit_insn (gen_nonlocal_goto_receiver ());
3259 /* Make handlers for nonlocal gotos taking place in the function calls in
3263 expand_nl_goto_receivers (thisblock)
3264 struct nesting *thisblock;
3267 rtx afterward = gen_label_rtx ();
3272 /* Record the handler address in the stack slot for that purpose,
3273 during this block, saving and restoring the outer value. */
3274 if (thisblock->next != 0)
3275 for (slot = nonlocal_goto_handler_slots; slot; slot = XEXP (slot, 1))
3277 rtx save_receiver = gen_reg_rtx (Pmode);
3278 emit_move_insn (XEXP (slot, 0), save_receiver);
3281 emit_move_insn (save_receiver, XEXP (slot, 0));
3282 insns = get_insns ();
3284 emit_insns_before (insns, thisblock->data.block.first_insn);
3287 /* Jump around the handlers; they run only when specially invoked. */
3288 emit_jump (afterward);
3290 /* Make a separate handler for each label. */
3291 link = nonlocal_labels;
3292 slot = nonlocal_goto_handler_slots;
3293 label_list = NULL_RTX;
3294 for (; link; link = TREE_CHAIN (link), slot = XEXP (slot, 1))
3295 /* Skip any labels we shouldn't be able to jump to from here,
3296 we generate one special handler for all of them below which just calls
3298 if (! DECL_TOO_LATE (TREE_VALUE (link)))
3301 lab = expand_nl_handler_label (XEXP (slot, 0),
3302 thisblock->data.block.first_insn);
3303 label_list = gen_rtx_EXPR_LIST (VOIDmode, lab, label_list);
3305 expand_nl_goto_receiver ();
3307 /* Jump to the "real" nonlocal label. */
3308 expand_goto (TREE_VALUE (link));
3311 /* A second pass over all nonlocal labels; this time we handle those
3312 we should not be able to jump to at this point. */
3313 link = nonlocal_labels;
3314 slot = nonlocal_goto_handler_slots;
3316 for (; link; link = TREE_CHAIN (link), slot = XEXP (slot, 1))
3317 if (DECL_TOO_LATE (TREE_VALUE (link)))
3320 lab = expand_nl_handler_label (XEXP (slot, 0),
3321 thisblock->data.block.first_insn);
3322 label_list = gen_rtx_EXPR_LIST (VOIDmode, lab, label_list);
3328 expand_nl_goto_receiver ();
3329 emit_library_call (gen_rtx_SYMBOL_REF (Pmode, "abort"), 0,
3334 nonlocal_goto_handler_labels = label_list;
3335 emit_label (afterward);
3338 /* Generate RTL code to terminate a binding contour.
3339 VARS is the chain of VAR_DECL nodes
3340 for the variables bound in this contour.
3341 MARK_ENDS is nonzero if we should put a note at the beginning
3342 and end of this binding contour.
3344 DONT_JUMP_IN is nonzero if it is not valid to jump into this contour.
3345 (That is true automatically if the contour has a saved stack level.) */
3348 expand_end_bindings (vars, mark_ends, dont_jump_in)
3353 register struct nesting *thisblock;
3356 while (block_stack->data.block.exception_region)
3358 /* Because we don't need or want a new temporary level and
3359 because we didn't create one in expand_eh_region_start,
3360 create a fake one now to avoid removing one in
3361 expand_end_bindings. */
3364 block_stack->data.block.exception_region = 0;
3366 expand_end_bindings (NULL_TREE, 0, 0);
3369 /* Since expand_eh_region_start does an expand_start_bindings, we
3370 have to first end all the bindings that were created by
3371 expand_eh_region_start. */
3373 thisblock = block_stack;
3376 for (decl = vars; decl; decl = TREE_CHAIN (decl))
3377 if (! TREE_USED (decl) && TREE_CODE (decl) == VAR_DECL
3378 && ! DECL_IN_SYSTEM_HEADER (decl)
3379 && DECL_NAME (decl) && ! DECL_ARTIFICIAL (decl))
3380 warning_with_decl (decl, "unused variable `%s'");
3382 if (thisblock->exit_label)
3384 do_pending_stack_adjust ();
3385 emit_label (thisblock->exit_label);
3388 /* If necessary, make handlers for nonlocal gotos taking
3389 place in the function calls in this block. */
3390 if (function_call_count != thisblock->data.block.function_call_count
3392 /* Make handler for outermost block
3393 if there were any nonlocal gotos to this function. */
3394 && (thisblock->next == 0 ? current_function_has_nonlocal_label
3395 /* Make handler for inner block if it has something
3396 special to do when you jump out of it. */
3397 : (thisblock->data.block.cleanups != 0
3398 || thisblock->data.block.stack_level != 0)))
3399 expand_nl_goto_receivers (thisblock);
3401 /* Don't allow jumping into a block that has a stack level.
3402 Cleanups are allowed, though. */
3404 || thisblock->data.block.stack_level != 0)
3406 struct label_chain *chain;
3408 /* Any labels in this block are no longer valid to go to.
3409 Mark them to cause an error message. */
3410 for (chain = thisblock->data.block.label_chain; chain; chain = chain->next)
3412 DECL_TOO_LATE (chain->label) = 1;
3413 /* If any goto without a fixup came to this label,
3414 that must be an error, because gotos without fixups
3415 come from outside all saved stack-levels. */
3416 if (TREE_ADDRESSABLE (chain->label))
3417 error_with_decl (chain->label,
3418 "label `%s' used before containing binding contour");
3422 /* Restore stack level in effect before the block
3423 (only if variable-size objects allocated). */
3424 /* Perform any cleanups associated with the block. */
3426 if (thisblock->data.block.stack_level != 0
3427 || thisblock->data.block.cleanups != 0)
3429 /* Only clean up here if this point can actually be reached. */
3430 int reachable = GET_CODE (get_last_insn ()) != BARRIER;
3432 /* Don't let cleanups affect ({...}) constructs. */
3433 int old_expr_stmts_for_value = expr_stmts_for_value;
3434 rtx old_last_expr_value = last_expr_value;
3435 tree old_last_expr_type = last_expr_type;
3436 expr_stmts_for_value = 0;
3438 /* Do the cleanups. */
3439 expand_cleanups (thisblock->data.block.cleanups, NULL_TREE, 0, reachable);
3441 do_pending_stack_adjust ();
3443 expr_stmts_for_value = old_expr_stmts_for_value;
3444 last_expr_value = old_last_expr_value;
3445 last_expr_type = old_last_expr_type;
3447 /* Restore the stack level. */
3449 if (reachable && thisblock->data.block.stack_level != 0)
3451 emit_stack_restore (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3452 thisblock->data.block.stack_level, NULL_RTX);
3453 if (nonlocal_goto_handler_slots != 0)
3454 emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level,
3458 /* Any gotos out of this block must also do these things.
3459 Also report any gotos with fixups that came to labels in this
3461 fixup_gotos (thisblock,
3462 thisblock->data.block.stack_level,
3463 thisblock->data.block.cleanups,
3464 thisblock->data.block.first_insn,
3468 /* Mark the beginning and end of the scope if requested.
3469 We do this now, after running cleanups on the variables
3470 just going out of scope, so they are in scope for their cleanups. */
3473 last_block_end_note = emit_note (NULL_PTR, NOTE_INSN_BLOCK_END);
3475 /* Get rid of the beginning-mark if we don't make an end-mark. */
3476 NOTE_LINE_NUMBER (thisblock->data.block.first_insn) = NOTE_INSN_DELETED;
3478 /* If doing stupid register allocation, make sure lives of all
3479 register variables declared here extend thru end of scope. */
3482 for (decl = vars; decl; decl = TREE_CHAIN (decl))
3484 rtx rtl = DECL_RTL (decl);
3485 if (TREE_CODE (decl) == VAR_DECL && rtl != 0)
3489 /* Restore the temporary level of TARGET_EXPRs. */
3490 target_temp_slot_level = thisblock->data.block.target_temp_slot_level;
3492 /* Restore block_stack level for containing block. */
3494 stack_block_stack = thisblock->data.block.innermost_stack_block;
3495 POPSTACK (block_stack);
3497 /* Pop the stack slot nesting and free any slots at this level. */
3501 /* Generate RTL for the automatic variable declaration DECL.
3502 (Other kinds of declarations are simply ignored if seen here.) */
3508 struct nesting *thisblock = block_stack;
3511 type = TREE_TYPE (decl);
3513 /* Only automatic variables need any expansion done.
3514 Static and external variables, and external functions,
3515 will be handled by `assemble_variable' (called from finish_decl).
3516 TYPE_DECL and CONST_DECL require nothing.
3517 PARM_DECLs are handled in `assign_parms'. */
3519 if (TREE_CODE (decl) != VAR_DECL)
3521 if (TREE_STATIC (decl) || DECL_EXTERNAL (decl))
3524 /* Create the RTL representation for the variable. */
3526 if (type == error_mark_node)
3527 DECL_RTL (decl) = gen_rtx_MEM (BLKmode, const0_rtx);
3528 else if (DECL_SIZE (decl) == 0)
3529 /* Variable with incomplete type. */
3531 if (DECL_INITIAL (decl) == 0)
3532 /* Error message was already done; now avoid a crash. */
3533 DECL_RTL (decl) = assign_stack_temp (DECL_MODE (decl), 0, 1);
3535 /* An initializer is going to decide the size of this array.
3536 Until we know the size, represent its address with a reg. */
3537 DECL_RTL (decl) = gen_rtx_MEM (BLKmode, gen_reg_rtx (Pmode));
3538 MEM_SET_IN_STRUCT_P (DECL_RTL (decl), AGGREGATE_TYPE_P (type));
3540 else if (DECL_MODE (decl) != BLKmode
3541 /* If -ffloat-store, don't put explicit float vars
3543 && !(flag_float_store
3544 && TREE_CODE (type) == REAL_TYPE)
3545 && ! TREE_THIS_VOLATILE (decl)
3546 && ! TREE_ADDRESSABLE (decl)
3547 && (DECL_REGISTER (decl) || ! obey_regdecls)
3548 /* if -fcheck-memory-usage, check all variables. */
3549 && ! current_function_check_memory_usage)
3551 /* Automatic variable that can go in a register. */
3552 int unsignedp = TREE_UNSIGNED (type);
3553 enum machine_mode reg_mode
3554 = promote_mode (type, DECL_MODE (decl), &unsignedp, 0);
3556 DECL_RTL (decl) = gen_reg_rtx (reg_mode);
3557 mark_user_reg (DECL_RTL (decl));
3559 if (POINTER_TYPE_P (type))
3560 mark_reg_pointer (DECL_RTL (decl),
3561 (TYPE_ALIGN (TREE_TYPE (TREE_TYPE (decl)))
3565 else if (TREE_CODE (DECL_SIZE (decl)) == INTEGER_CST
3566 && ! (flag_stack_check && ! STACK_CHECK_BUILTIN
3567 && (TREE_INT_CST_HIGH (DECL_SIZE (decl)) != 0
3568 || (TREE_INT_CST_LOW (DECL_SIZE (decl))
3569 > STACK_CHECK_MAX_VAR_SIZE * BITS_PER_UNIT))))
3571 /* Variable of fixed size that goes on the stack. */
3575 /* If we previously made RTL for this decl, it must be an array
3576 whose size was determined by the initializer.
3577 The old address was a register; set that register now
3578 to the proper address. */
3579 if (DECL_RTL (decl) != 0)
3581 if (GET_CODE (DECL_RTL (decl)) != MEM
3582 || GET_CODE (XEXP (DECL_RTL (decl), 0)) != REG)
3584 oldaddr = XEXP (DECL_RTL (decl), 0);
3587 DECL_RTL (decl) = assign_temp (TREE_TYPE (decl), 1, 1, 1);
3588 MEM_SET_IN_STRUCT_P (DECL_RTL (decl),
3589 AGGREGATE_TYPE_P (TREE_TYPE (decl)));
3591 /* Set alignment we actually gave this decl. */
3592 DECL_ALIGN (decl) = (DECL_MODE (decl) == BLKmode ? BIGGEST_ALIGNMENT
3593 : GET_MODE_BITSIZE (DECL_MODE (decl)));
3597 addr = force_operand (XEXP (DECL_RTL (decl), 0), oldaddr);
3598 if (addr != oldaddr)
3599 emit_move_insn (oldaddr, addr);
3602 /* If this is a memory ref that contains aggregate components,
3603 mark it as such for cse and loop optimize. */
3604 MEM_SET_IN_STRUCT_P (DECL_RTL (decl),
3605 AGGREGATE_TYPE_P (TREE_TYPE (decl)));
3607 /* If this is in memory because of -ffloat-store,
3608 set the volatile bit, to prevent optimizations from
3609 undoing the effects. */
3610 if (flag_float_store && TREE_CODE (type) == REAL_TYPE)
3611 MEM_VOLATILE_P (DECL_RTL (decl)) = 1;
3614 MEM_ALIAS_SET (DECL_RTL (decl)) = get_alias_set (decl);
3617 /* Dynamic-size object: must push space on the stack. */
3621 /* Record the stack pointer on entry to block, if have
3622 not already done so. */
3623 if (thisblock->data.block.stack_level == 0)
3625 do_pending_stack_adjust ();
3626 emit_stack_save (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3627 &thisblock->data.block.stack_level,
3628 thisblock->data.block.first_insn);
3629 stack_block_stack = thisblock;
3632 /* Compute the variable's size, in bytes. */
3633 size = expand_expr (size_binop (CEIL_DIV_EXPR,
3635 size_int (BITS_PER_UNIT)),
3636 NULL_RTX, VOIDmode, 0);
3639 /* Allocate space on the stack for the variable. Note that
3640 DECL_ALIGN says how the variable is to be aligned and we
3641 cannot use it to conclude anything about the alignment of
3643 address = allocate_dynamic_stack_space (size, NULL_RTX,
3644 TYPE_ALIGN (TREE_TYPE (decl)));
3646 /* Reference the variable indirect through that rtx. */
3647 DECL_RTL (decl) = gen_rtx_MEM (DECL_MODE (decl), address);
3649 /* If this is a memory ref that contains aggregate components,
3650 mark it as such for cse and loop optimize. */
3651 MEM_SET_IN_STRUCT_P (DECL_RTL (decl),
3652 AGGREGATE_TYPE_P (TREE_TYPE (decl)));
3654 /* Indicate the alignment we actually gave this variable. */
3655 #ifdef STACK_BOUNDARY
3656 DECL_ALIGN (decl) = STACK_BOUNDARY;
3658 DECL_ALIGN (decl) = BIGGEST_ALIGNMENT;
3662 if (TREE_THIS_VOLATILE (decl))
3663 MEM_VOLATILE_P (DECL_RTL (decl)) = 1;
3664 #if 0 /* A variable is not necessarily unchanging
3665 just because it is const. RTX_UNCHANGING_P
3666 means no change in the function,
3667 not merely no change in the variable's scope.
3668 It is correct to set RTX_UNCHANGING_P if the variable's scope
3669 is the whole function. There's no convenient way to test that. */
3670 if (TREE_READONLY (decl))
3671 RTX_UNCHANGING_P (DECL_RTL (decl)) = 1;
3674 /* If doing stupid register allocation, make sure life of any
3675 register variable starts here, at the start of its scope. */
3678 use_variable (DECL_RTL (decl));
3683 /* Emit code to perform the initialization of a declaration DECL. */
3686 expand_decl_init (decl)
3689 int was_used = TREE_USED (decl);
3691 /* If this is a CONST_DECL, we don't have to generate any code, but
3692 if DECL_INITIAL is a constant, call expand_expr to force TREE_CST_RTL
3693 to be set while in the obstack containing the constant. If we don't
3694 do this, we can lose if we have functions nested three deep and the middle
3695 function makes a CONST_DECL whose DECL_INITIAL is a STRING_CST while
3696 the innermost function is the first to expand that STRING_CST. */
3697 if (TREE_CODE (decl) == CONST_DECL)
3699 if (DECL_INITIAL (decl) && TREE_CONSTANT (DECL_INITIAL (decl)))
3700 expand_expr (DECL_INITIAL (decl), NULL_RTX, VOIDmode,
3701 EXPAND_INITIALIZER);
3705 if (TREE_STATIC (decl))
3708 /* Compute and store the initial value now. */
3710 if (DECL_INITIAL (decl) == error_mark_node)
3712 enum tree_code code = TREE_CODE (TREE_TYPE (decl));
3714 if (code == INTEGER_TYPE || code == REAL_TYPE || code == ENUMERAL_TYPE
3715 || code == POINTER_TYPE || code == REFERENCE_TYPE)
3716 expand_assignment (decl, convert (TREE_TYPE (decl), integer_zero_node),
3720 else if (DECL_INITIAL (decl) && TREE_CODE (DECL_INITIAL (decl)) != TREE_LIST)
3722 emit_line_note (DECL_SOURCE_FILE (decl), DECL_SOURCE_LINE (decl));
3723 expand_assignment (decl, DECL_INITIAL (decl), 0, 0);
3727 /* Don't let the initialization count as "using" the variable. */
3728 TREE_USED (decl) = was_used;
3730 /* Free any temporaries we made while initializing the decl. */
3731 preserve_temp_slots (NULL_RTX);
3735 /* CLEANUP is an expression to be executed at exit from this binding contour;
3736 for example, in C++, it might call the destructor for this variable.
3738 We wrap CLEANUP in an UNSAVE_EXPR node, so that we can expand the
3739 CLEANUP multiple times, and have the correct semantics. This
3740 happens in exception handling, for gotos, returns, breaks that
3741 leave the current scope.
3743 If CLEANUP is nonzero and DECL is zero, we record a cleanup
3744 that is not associated with any particular variable. */
3747 expand_decl_cleanup (decl, cleanup)
3750 struct nesting *thisblock = block_stack;
3752 /* Error if we are not in any block. */
3756 /* Record the cleanup if there is one. */
3762 tree *cleanups = &thisblock->data.block.cleanups;
3763 int cond_context = conditional_context ();
3767 rtx flag = gen_reg_rtx (word_mode);
3772 emit_move_insn (flag, const0_rtx);
3773 set_flag_0 = get_insns ();
3776 thisblock->data.block.last_unconditional_cleanup
3777 = emit_insns_after (set_flag_0,
3778 thisblock->data.block.last_unconditional_cleanup);
3780 emit_move_insn (flag, const1_rtx);
3782 /* All cleanups must be on the function_obstack. */
3783 push_obstacks_nochange ();
3784 resume_temporary_allocation ();
3786 cond = build_decl (VAR_DECL, NULL_TREE, type_for_mode (word_mode, 1));
3787 DECL_RTL (cond) = flag;
3789 /* Conditionalize the cleanup. */
3790 cleanup = build (COND_EXPR, void_type_node,
3791 truthvalue_conversion (cond),
3792 cleanup, integer_zero_node);
3793 cleanup = fold (cleanup);
3797 cleanups = thisblock->data.block.cleanup_ptr;
3800 /* All cleanups must be on the function_obstack. */
3801 push_obstacks_nochange ();
3802 resume_temporary_allocation ();
3803 cleanup = unsave_expr (cleanup);
3806 t = *cleanups = temp_tree_cons (decl, cleanup, *cleanups);
3809 /* If this block has a cleanup, it belongs in stack_block_stack. */
3810 stack_block_stack = thisblock;
3817 /* If this was optimized so that there is no exception region for the
3818 cleanup, then mark the TREE_LIST node, so that we can later tell
3819 if we need to call expand_eh_region_end. */
3820 if (! using_eh_for_cleanups_p
3821 || expand_eh_region_start_tree (decl, cleanup))
3822 TREE_ADDRESSABLE (t) = 1;
3823 /* If that started a new EH region, we're in a new block. */
3824 thisblock = block_stack;
3831 thisblock->data.block.last_unconditional_cleanup
3832 = emit_insns_after (seq,
3833 thisblock->data.block.last_unconditional_cleanup);
3837 thisblock->data.block.last_unconditional_cleanup
3839 thisblock->data.block.cleanup_ptr = &thisblock->data.block.cleanups;
3845 /* Like expand_decl_cleanup, but suppress generating an exception handler
3846 to perform the cleanup. */
3849 expand_decl_cleanup_no_eh (decl, cleanup)
3852 int save_eh = using_eh_for_cleanups_p;
3855 using_eh_for_cleanups_p = 0;
3856 result = expand_decl_cleanup (decl, cleanup);
3857 using_eh_for_cleanups_p = save_eh;
3862 /* Arrange for the top element of the dynamic cleanup chain to be
3863 popped if we exit the current binding contour. DECL is the
3864 associated declaration, if any, otherwise NULL_TREE. If the
3865 current contour is left via an exception, then __sjthrow will pop
3866 the top element off the dynamic cleanup chain. The code that
3867 avoids doing the action we push into the cleanup chain in the
3868 exceptional case is contained in expand_cleanups.
3870 This routine is only used by expand_eh_region_start, and that is
3871 the only way in which an exception region should be started. This
3872 routine is only used when using the setjmp/longjmp codegen method
3873 for exception handling. */
3876 expand_dcc_cleanup (decl)
3879 struct nesting *thisblock = block_stack;
3882 /* Error if we are not in any block. */
3886 /* Record the cleanup for the dynamic handler chain. */
3888 /* All cleanups must be on the function_obstack. */
3889 push_obstacks_nochange ();
3890 resume_temporary_allocation ();
3891 cleanup = make_node (POPDCC_EXPR);
3894 /* Add the cleanup in a manner similar to expand_decl_cleanup. */
3895 thisblock->data.block.cleanups
3896 = temp_tree_cons (decl, cleanup, thisblock->data.block.cleanups);
3898 /* If this block has a cleanup, it belongs in stack_block_stack. */
3899 stack_block_stack = thisblock;
3903 /* Arrange for the top element of the dynamic handler chain to be
3904 popped if we exit the current binding contour. DECL is the
3905 associated declaration, if any, otherwise NULL_TREE. If the current
3906 contour is left via an exception, then __sjthrow will pop the top
3907 element off the dynamic handler chain. The code that avoids doing
3908 the action we push into the handler chain in the exceptional case
3909 is contained in expand_cleanups.
3911 This routine is only used by expand_eh_region_start, and that is
3912 the only way in which an exception region should be started. This
3913 routine is only used when using the setjmp/longjmp codegen method
3914 for exception handling. */
3917 expand_dhc_cleanup (decl)
3920 struct nesting *thisblock = block_stack;
3923 /* Error if we are not in any block. */
3927 /* Record the cleanup for the dynamic handler chain. */
3929 /* All cleanups must be on the function_obstack. */
3930 push_obstacks_nochange ();
3931 resume_temporary_allocation ();
3932 cleanup = make_node (POPDHC_EXPR);
3935 /* Add the cleanup in a manner similar to expand_decl_cleanup. */
3936 thisblock->data.block.cleanups
3937 = temp_tree_cons (decl, cleanup, thisblock->data.block.cleanups);
3939 /* If this block has a cleanup, it belongs in stack_block_stack. */
3940 stack_block_stack = thisblock;
3944 /* DECL is an anonymous union. CLEANUP is a cleanup for DECL.
3945 DECL_ELTS is the list of elements that belong to DECL's type.
3946 In each, the TREE_VALUE is a VAR_DECL, and the TREE_PURPOSE a cleanup. */
3949 expand_anon_union_decl (decl, cleanup, decl_elts)
3950 tree decl, cleanup, decl_elts;
3952 struct nesting *thisblock = block_stack;
3956 expand_decl_cleanup (decl, cleanup);
3957 x = DECL_RTL (decl);
3961 tree decl_elt = TREE_VALUE (decl_elts);
3962 tree cleanup_elt = TREE_PURPOSE (decl_elts);
3963 enum machine_mode mode = TYPE_MODE (TREE_TYPE (decl_elt));
3965 /* Propagate the union's alignment to the elements. */
3966 DECL_ALIGN (decl_elt) = DECL_ALIGN (decl);
3968 /* If the element has BLKmode and the union doesn't, the union is
3969 aligned such that the element doesn't need to have BLKmode, so
3970 change the element's mode to the appropriate one for its size. */
3971 if (mode == BLKmode && DECL_MODE (decl) != BLKmode)
3972 DECL_MODE (decl_elt) = mode
3973 = mode_for_size (TREE_INT_CST_LOW (DECL_SIZE (decl_elt)),
3976 /* (SUBREG (MEM ...)) at RTL generation time is invalid, so we
3977 instead create a new MEM rtx with the proper mode. */
3978 if (GET_CODE (x) == MEM)
3980 if (mode == GET_MODE (x))
3981 DECL_RTL (decl_elt) = x;
3984 DECL_RTL (decl_elt) = gen_rtx_MEM (mode, copy_rtx (XEXP (x, 0)));
3985 MEM_COPY_ATTRIBUTES (DECL_RTL (decl_elt), x);
3986 RTX_UNCHANGING_P (DECL_RTL (decl_elt)) = RTX_UNCHANGING_P (x);
3989 else if (GET_CODE (x) == REG)
3991 if (mode == GET_MODE (x))
3992 DECL_RTL (decl_elt) = x;
3994 DECL_RTL (decl_elt) = gen_rtx_SUBREG (mode, x, 0);
3999 /* Record the cleanup if there is one. */
4002 thisblock->data.block.cleanups
4003 = temp_tree_cons (decl_elt, cleanup_elt,
4004 thisblock->data.block.cleanups);
4006 decl_elts = TREE_CHAIN (decl_elts);
4010 /* Expand a list of cleanups LIST.
4011 Elements may be expressions or may be nested lists.
4013 If DONT_DO is nonnull, then any list-element
4014 whose TREE_PURPOSE matches DONT_DO is omitted.
4015 This is sometimes used to avoid a cleanup associated with
4016 a value that is being returned out of the scope.
4018 If IN_FIXUP is non-zero, we are generating this cleanup for a fixup
4019 goto and handle protection regions specially in that case.
4021 If REACHABLE, we emit code, otherwise just inform the exception handling
4022 code about this finalization. */
4025 expand_cleanups (list, dont_do, in_fixup, reachable)
4032 for (tail = list; tail; tail = TREE_CHAIN (tail))
4033 if (dont_do == 0 || TREE_PURPOSE (tail) != dont_do)
4035 if (TREE_CODE (TREE_VALUE (tail)) == TREE_LIST)
4036 expand_cleanups (TREE_VALUE (tail), dont_do, in_fixup, reachable);
4041 tree cleanup = TREE_VALUE (tail);
4043 /* See expand_d{h,c}c_cleanup for why we avoid this. */
4044 if (TREE_CODE (cleanup) != POPDHC_EXPR
4045 && TREE_CODE (cleanup) != POPDCC_EXPR
4046 /* See expand_eh_region_start_tree for this case. */
4047 && ! TREE_ADDRESSABLE (tail))
4049 cleanup = protect_with_terminate (cleanup);
4050 expand_eh_region_end (cleanup);
4056 /* Cleanups may be run multiple times. For example,
4057 when exiting a binding contour, we expand the
4058 cleanups associated with that contour. When a goto
4059 within that binding contour has a target outside that
4060 contour, it will expand all cleanups from its scope to
4061 the target. Though the cleanups are expanded multiple
4062 times, the control paths are non-overlapping so the
4063 cleanups will not be executed twice. */
4065 /* We may need to protect fixups with rethrow regions. */
4066 int protect = (in_fixup && ! TREE_ADDRESSABLE (tail));
4069 expand_fixup_region_start ();
4071 expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0);
4073 expand_fixup_region_end (TREE_VALUE (tail));
4080 /* Mark when the context we are emitting RTL for as a conditional
4081 context, so that any cleanup actions we register with
4082 expand_decl_init will be properly conditionalized when those
4083 cleanup actions are later performed. Must be called before any
4084 expression (tree) is expanded that is within a conditional context. */
4087 start_cleanup_deferral ()
4089 /* block_stack can be NULL if we are inside the parameter list. It is
4090 OK to do nothing, because cleanups aren't possible here. */
4092 ++block_stack->data.block.conditional_code;
4095 /* Mark the end of a conditional region of code. Because cleanup
4096 deferrals may be nested, we may still be in a conditional region
4097 after we end the currently deferred cleanups, only after we end all
4098 deferred cleanups, are we back in unconditional code. */
4101 end_cleanup_deferral ()
4103 /* block_stack can be NULL if we are inside the parameter list. It is
4104 OK to do nothing, because cleanups aren't possible here. */
4106 --block_stack->data.block.conditional_code;
4109 /* Move all cleanups from the current block_stack
4110 to the containing block_stack, where they are assumed to
4111 have been created. If anything can cause a temporary to
4112 be created, but not expanded for more than one level of
4113 block_stacks, then this code will have to change. */
4118 struct nesting *block = block_stack;
4119 struct nesting *outer = block->next;
4121 outer->data.block.cleanups
4122 = chainon (block->data.block.cleanups,
4123 outer->data.block.cleanups);
4124 block->data.block.cleanups = 0;
4128 last_cleanup_this_contour ()
4130 if (block_stack == 0)
4133 return block_stack->data.block.cleanups;
4136 /* Return 1 if there are any pending cleanups at this point.
4137 If THIS_CONTOUR is nonzero, check the current contour as well.
4138 Otherwise, look only at the contours that enclose this one. */
4141 any_pending_cleanups (this_contour)
4144 struct nesting *block;
4146 if (block_stack == 0)
4149 if (this_contour && block_stack->data.block.cleanups != NULL)
4151 if (block_stack->data.block.cleanups == 0
4152 && block_stack->data.block.outer_cleanups == 0)
4155 for (block = block_stack->next; block; block = block->next)
4156 if (block->data.block.cleanups != 0)
4162 /* Enter a case (Pascal) or switch (C) statement.
4163 Push a block onto case_stack and nesting_stack
4164 to accumulate the case-labels that are seen
4165 and to record the labels generated for the statement.
4167 EXIT_FLAG is nonzero if `exit_something' should exit this case stmt.
4168 Otherwise, this construct is transparent for `exit_something'.
4170 EXPR is the index-expression to be dispatched on.
4171 TYPE is its nominal type. We could simply convert EXPR to this type,
4172 but instead we take short cuts. */
4175 expand_start_case (exit_flag, expr, type, printname)
4179 const char *printname;
4181 register struct nesting *thiscase = ALLOC_NESTING ();
4183 /* Make an entry on case_stack for the case we are entering. */
4185 thiscase->next = case_stack;
4186 thiscase->all = nesting_stack;
4187 thiscase->depth = ++nesting_depth;
4188 thiscase->exit_label = exit_flag ? gen_label_rtx () : 0;
4189 thiscase->data.case_stmt.case_list = 0;
4190 thiscase->data.case_stmt.index_expr = expr;
4191 thiscase->data.case_stmt.nominal_type = type;
4192 thiscase->data.case_stmt.default_label = 0;
4193 thiscase->data.case_stmt.num_ranges = 0;
4194 thiscase->data.case_stmt.printname = printname;
4195 thiscase->data.case_stmt.line_number_status = force_line_numbers ();
4196 case_stack = thiscase;
4197 nesting_stack = thiscase;
4199 do_pending_stack_adjust ();
4201 /* Make sure case_stmt.start points to something that won't
4202 need any transformation before expand_end_case. */
4203 if (GET_CODE (get_last_insn ()) != NOTE)
4204 emit_note (NULL_PTR, NOTE_INSN_DELETED);
4206 thiscase->data.case_stmt.start = get_last_insn ();
4208 start_cleanup_deferral ();
4212 /* Start a "dummy case statement" within which case labels are invalid
4213 and are not connected to any larger real case statement.
4214 This can be used if you don't want to let a case statement jump
4215 into the middle of certain kinds of constructs. */
4218 expand_start_case_dummy ()
4220 register struct nesting *thiscase = ALLOC_NESTING ();
4222 /* Make an entry on case_stack for the dummy. */
4224 thiscase->next = case_stack;
4225 thiscase->all = nesting_stack;
4226 thiscase->depth = ++nesting_depth;
4227 thiscase->exit_label = 0;
4228 thiscase->data.case_stmt.case_list = 0;
4229 thiscase->data.case_stmt.start = 0;
4230 thiscase->data.case_stmt.nominal_type = 0;
4231 thiscase->data.case_stmt.default_label = 0;
4232 thiscase->data.case_stmt.num_ranges = 0;
4233 case_stack = thiscase;
4234 nesting_stack = thiscase;
4235 start_cleanup_deferral ();
4238 /* End a dummy case statement. */
4241 expand_end_case_dummy ()
4243 end_cleanup_deferral ();
4244 POPSTACK (case_stack);
4247 /* Return the data type of the index-expression
4248 of the innermost case statement, or null if none. */
4251 case_index_expr_type ()
4254 return TREE_TYPE (case_stack->data.case_stmt.index_expr);
4261 /* If this is the first label, warn if any insns have been emitted. */
4262 if (case_stack->data.case_stmt.line_number_status >= 0)
4266 restore_line_number_status
4267 (case_stack->data.case_stmt.line_number_status);
4268 case_stack->data.case_stmt.line_number_status = -1;
4270 for (insn = case_stack->data.case_stmt.start;
4272 insn = NEXT_INSN (insn))
4274 if (GET_CODE (insn) == CODE_LABEL)
4276 if (GET_CODE (insn) != NOTE
4277 && (GET_CODE (insn) != INSN || GET_CODE (PATTERN (insn)) != USE))
4280 insn = PREV_INSN (insn);
4281 while (insn && (GET_CODE (insn) != NOTE || NOTE_LINE_NUMBER (insn) < 0));
4283 /* If insn is zero, then there must have been a syntax error. */
4285 warning_with_file_and_line (NOTE_SOURCE_FILE(insn),
4286 NOTE_LINE_NUMBER(insn),
4287 "unreachable code at beginning of %s",
4288 case_stack->data.case_stmt.printname);
4295 /* Accumulate one case or default label inside a case or switch statement.
4296 VALUE is the value of the case (a null pointer, for a default label).
4297 The function CONVERTER, when applied to arguments T and V,
4298 converts the value V to the type T.
4300 If not currently inside a case or switch statement, return 1 and do
4301 nothing. The caller will print a language-specific error message.
4302 If VALUE is a duplicate or overlaps, return 2 and do nothing
4303 except store the (first) duplicate node in *DUPLICATE.
4304 If VALUE is out of range, return 3 and do nothing.
4305 If we are jumping into the scope of a cleanup or var-sized array, return 5.
4306 Return 0 on success.
4308 Extended to handle range statements. */
4311 pushcase (value, converter, label, duplicate)
4312 register tree value;
4313 tree (*converter) PROTO((tree, tree));
4314 register tree label;
4320 /* Fail if not inside a real case statement. */
4321 if (! (case_stack && case_stack->data.case_stmt.start))
4324 if (stack_block_stack
4325 && stack_block_stack->depth > case_stack->depth)
4328 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
4329 nominal_type = case_stack->data.case_stmt.nominal_type;
4331 /* If the index is erroneous, avoid more problems: pretend to succeed. */
4332 if (index_type == error_mark_node)
4335 /* Convert VALUE to the type in which the comparisons are nominally done. */
4337 value = (*converter) (nominal_type, value);
4341 /* Fail if this value is out of range for the actual type of the index
4342 (which may be narrower than NOMINAL_TYPE). */
4343 if (value != 0 && ! int_fits_type_p (value, index_type))
4346 /* Fail if this is a duplicate or overlaps another entry. */
4349 if (case_stack->data.case_stmt.default_label != 0)
4351 *duplicate = case_stack->data.case_stmt.default_label;
4354 case_stack->data.case_stmt.default_label = label;
4357 return add_case_node (value, value, label, duplicate);
4359 expand_label (label);
4363 /* Like pushcase but this case applies to all values between VALUE1 and
4364 VALUE2 (inclusive). If VALUE1 is NULL, the range starts at the lowest
4365 value of the index type and ends at VALUE2. If VALUE2 is NULL, the range
4366 starts at VALUE1 and ends at the highest value of the index type.
4367 If both are NULL, this case applies to all values.
4369 The return value is the same as that of pushcase but there is one
4370 additional error code: 4 means the specified range was empty. */
4373 pushcase_range (value1, value2, converter, label, duplicate)
4374 register tree value1, value2;
4375 tree (*converter) PROTO((tree, tree));
4376 register tree label;
4382 /* Fail if not inside a real case statement. */
4383 if (! (case_stack && case_stack->data.case_stmt.start))
4386 if (stack_block_stack
4387 && stack_block_stack->depth > case_stack->depth)
4390 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
4391 nominal_type = case_stack->data.case_stmt.nominal_type;
4393 /* If the index is erroneous, avoid more problems: pretend to succeed. */
4394 if (index_type == error_mark_node)
4399 /* Convert VALUEs to type in which the comparisons are nominally done
4400 and replace any unspecified value with the corresponding bound. */
4402 value1 = TYPE_MIN_VALUE (index_type);
4404 value2 = TYPE_MAX_VALUE (index_type);
4406 /* Fail if the range is empty. Do this before any conversion since
4407 we want to allow out-of-range empty ranges. */
4408 if (value2 && tree_int_cst_lt (value2, value1))
4411 value1 = (*converter) (nominal_type, value1);
4413 /* If the max was unbounded, use the max of the nominal_type we are
4414 converting to. Do this after the < check above to suppress false
4417 value2 = TYPE_MAX_VALUE (nominal_type);
4418 value2 = (*converter) (nominal_type, value2);
4420 /* Fail if these values are out of range. */
4421 if (TREE_CONSTANT_OVERFLOW (value1)
4422 || ! int_fits_type_p (value1, index_type))
4425 if (TREE_CONSTANT_OVERFLOW (value2)
4426 || ! int_fits_type_p (value2, index_type))
4429 return add_case_node (value1, value2, label, duplicate);
4432 /* Do the actual insertion of a case label for pushcase and pushcase_range
4433 into case_stack->data.case_stmt.case_list. Use an AVL tree to avoid
4434 slowdown for large switch statements. */
4437 add_case_node (low, high, label, duplicate)
4442 struct case_node *p, **q, *r;
4444 q = &case_stack->data.case_stmt.case_list;
4451 /* Keep going past elements distinctly greater than HIGH. */
4452 if (tree_int_cst_lt (high, p->low))
4455 /* or distinctly less than LOW. */
4456 else if (tree_int_cst_lt (p->high, low))
4461 /* We have an overlap; this is an error. */
4462 *duplicate = p->code_label;
4467 /* Add this label to the chain, and succeed.
4468 Copy LOW, HIGH so they are on temporary rather than momentary
4469 obstack and will thus survive till the end of the case statement. */
4471 r = (struct case_node *) oballoc (sizeof (struct case_node));
4472 r->low = copy_node (low);
4474 /* If the bounds are equal, turn this into the one-value case. */
4476 if (tree_int_cst_equal (low, high))
4480 r->high = copy_node (high);
4481 case_stack->data.case_stmt.num_ranges++;
4484 r->code_label = label;
4485 expand_label (label);
4495 struct case_node *s;
4501 if (! (b = p->balance))
4502 /* Growth propagation from left side. */
4509 if ((p->left = s = r->right))
4518 if ((r->parent = s))
4526 case_stack->data.case_stmt.case_list = r;
4529 /* r->balance == +1 */
4534 struct case_node *t = r->right;
4536 if ((p->left = s = t->right))
4540 if ((r->right = s = t->left))
4554 if ((t->parent = s))
4562 case_stack->data.case_stmt.case_list = t;
4569 /* p->balance == +1; growth of left side balances the node. */
4579 if (! (b = p->balance))
4580 /* Growth propagation from right side. */
4588 if ((p->right = s = r->left))
4596 if ((r->parent = s))
4605 case_stack->data.case_stmt.case_list = r;
4609 /* r->balance == -1 */
4613 struct case_node *t = r->left;
4615 if ((p->right = s = t->left))
4620 if ((r->left = s = t->right))
4634 if ((t->parent = s))
4643 case_stack->data.case_stmt.case_list = t;
4649 /* p->balance == -1; growth of right side balances the node. */
4663 /* Returns the number of possible values of TYPE.
4664 Returns -1 if the number is unknown or variable.
4665 Returns -2 if the number does not fit in a HOST_WIDE_INT.
4666 Sets *SPARENESS to 2 if TYPE is an ENUMERAL_TYPE whose values
4667 do not increase monotonically (there may be duplicates);
4668 to 1 if the values increase monotonically, but not always by 1;
4669 otherwise sets it to 0. */
4672 all_cases_count (type, spareness)
4676 HOST_WIDE_INT count;
4679 switch (TREE_CODE (type))
4686 count = 1 << BITS_PER_UNIT;
4690 if (TREE_CODE (TYPE_MIN_VALUE (type)) != INTEGER_CST
4691 || TYPE_MAX_VALUE (type) == NULL
4692 || TREE_CODE (TYPE_MAX_VALUE (type)) != INTEGER_CST)
4697 = TREE_INT_CST_LOW (TYPE_MAX_VALUE (type))
4698 - TREE_INT_CST_LOW (TYPE_MIN_VALUE (type)) + 1
4699 but with overflow checking. */
4700 tree mint = TYPE_MIN_VALUE (type);
4701 tree maxt = TYPE_MAX_VALUE (type);
4702 HOST_WIDE_INT lo, hi;
4703 neg_double(TREE_INT_CST_LOW (mint), TREE_INT_CST_HIGH (mint),
4705 add_double(TREE_INT_CST_LOW (maxt), TREE_INT_CST_HIGH (maxt),
4707 add_double (lo, hi, 1, 0, &lo, &hi);
4708 if (hi != 0 || lo < 0)
4715 for (t = TYPE_VALUES (type); t != NULL_TREE; t = TREE_CHAIN (t))
4717 if (TREE_CODE (TYPE_MIN_VALUE (type)) != INTEGER_CST
4718 || TREE_CODE (TREE_VALUE (t)) != INTEGER_CST
4719 || TREE_INT_CST_LOW (TYPE_MIN_VALUE (type)) + count
4720 != TREE_INT_CST_LOW (TREE_VALUE (t)))
4724 if (*spareness == 1)
4726 tree prev = TREE_VALUE (TYPE_VALUES (type));
4727 for (t = TYPE_VALUES (type); t = TREE_CHAIN (t), t != NULL_TREE; )
4729 if (! tree_int_cst_lt (prev, TREE_VALUE (t)))
4734 prev = TREE_VALUE (t);
4743 #define BITARRAY_TEST(ARRAY, INDEX) \
4744 ((ARRAY)[(unsigned) (INDEX) / HOST_BITS_PER_CHAR]\
4745 & (1 << ((unsigned) (INDEX) % HOST_BITS_PER_CHAR)))
4746 #define BITARRAY_SET(ARRAY, INDEX) \
4747 ((ARRAY)[(unsigned) (INDEX) / HOST_BITS_PER_CHAR]\
4748 |= 1 << ((unsigned) (INDEX) % HOST_BITS_PER_CHAR))
4750 /* Set the elements of the bitstring CASES_SEEN (which has length COUNT),
4751 with the case values we have seen, assuming the case expression
4753 SPARSENESS is as determined by all_cases_count.
4755 The time needed is proportional to COUNT, unless
4756 SPARSENESS is 2, in which case quadratic time is needed. */
4759 mark_seen_cases (type, cases_seen, count, sparseness)
4761 unsigned char *cases_seen;
4765 tree next_node_to_try = NULL_TREE;
4766 long next_node_offset = 0;
4768 register struct case_node *n, *root = case_stack->data.case_stmt.case_list;
4769 tree val = make_node (INTEGER_CST);
4770 TREE_TYPE (val) = type;
4773 else if (sparseness == 2)
4778 /* This less efficient loop is only needed to handle
4779 duplicate case values (multiple enum constants
4780 with the same value). */
4781 TREE_TYPE (val) = TREE_TYPE (root->low);
4782 for (t = TYPE_VALUES (type), xlo = 0; t != NULL_TREE;
4783 t = TREE_CHAIN (t), xlo++)
4785 TREE_INT_CST_LOW (val) = TREE_INT_CST_LOW (TREE_VALUE (t));
4786 TREE_INT_CST_HIGH (val) = TREE_INT_CST_HIGH (TREE_VALUE (t));
4790 /* Keep going past elements distinctly greater than VAL. */
4791 if (tree_int_cst_lt (val, n->low))
4794 /* or distinctly less than VAL. */
4795 else if (tree_int_cst_lt (n->high, val))
4800 /* We have found a matching range. */
4801 BITARRAY_SET (cases_seen, xlo);
4811 case_stack->data.case_stmt.case_list = root = case_tree2list (root, 0);
4812 for (n = root; n; n = n->right)
4814 TREE_INT_CST_LOW (val) = TREE_INT_CST_LOW (n->low);
4815 TREE_INT_CST_HIGH (val) = TREE_INT_CST_HIGH (n->low);
4816 while ( ! tree_int_cst_lt (n->high, val))
4818 /* Calculate (into xlo) the "offset" of the integer (val).
4819 The element with lowest value has offset 0, the next smallest
4820 element has offset 1, etc. */
4822 HOST_WIDE_INT xlo, xhi;
4824 if (sparseness && TYPE_VALUES (type) != NULL_TREE)
4826 /* The TYPE_VALUES will be in increasing order, so
4827 starting searching where we last ended. */
4828 t = next_node_to_try;
4829 xlo = next_node_offset;
4835 t = TYPE_VALUES (type);
4838 if (tree_int_cst_equal (val, TREE_VALUE (t)))
4840 next_node_to_try = TREE_CHAIN (t);
4841 next_node_offset = xlo + 1;
4846 if (t == next_node_to_try)
4855 t = TYPE_MIN_VALUE (type);
4857 neg_double (TREE_INT_CST_LOW (t), TREE_INT_CST_HIGH (t),
4861 add_double (xlo, xhi,
4862 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val),
4866 if (xhi == 0 && xlo >= 0 && xlo < count)
4867 BITARRAY_SET (cases_seen, xlo);
4868 add_double (TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val),
4870 &TREE_INT_CST_LOW (val), &TREE_INT_CST_HIGH (val));
4876 /* Called when the index of a switch statement is an enumerated type
4877 and there is no default label.
4879 Checks that all enumeration literals are covered by the case
4880 expressions of a switch. Also, warn if there are any extra
4881 switch cases that are *not* elements of the enumerated type.
4883 If all enumeration literals were covered by the case expressions,
4884 turn one of the expressions into the default expression since it should
4885 not be possible to fall through such a switch. */
4888 check_for_full_enumeration_handling (type)
4891 register struct case_node *n;
4892 register tree chain;
4893 #if 0 /* variable used by 'if 0'ed code below. */
4894 register struct case_node **l;
4898 /* True iff the selector type is a numbered set mode. */
4901 /* The number of possible selector values. */
4904 /* For each possible selector value. a one iff it has been matched
4905 by a case value alternative. */
4906 unsigned char *cases_seen;
4908 /* The allocated size of cases_seen, in chars. */
4914 size = all_cases_count (type, &sparseness);
4915 bytes_needed = (size + HOST_BITS_PER_CHAR) / HOST_BITS_PER_CHAR;
4917 if (size > 0 && size < 600000
4918 /* We deliberately use malloc here - not xmalloc. */
4919 && (cases_seen = (unsigned char *) malloc (bytes_needed)) != NULL)
4922 tree v = TYPE_VALUES (type);
4923 bzero (cases_seen, bytes_needed);
4925 /* The time complexity of this code is normally O(N), where
4926 N being the number of members in the enumerated type.
4927 However, if type is a ENUMERAL_TYPE whose values do not
4928 increase monotonically, O(N*log(N)) time may be needed. */
4930 mark_seen_cases (type, cases_seen, size, sparseness);
4932 for (i = 0; v != NULL_TREE && i < size; i++, v = TREE_CHAIN (v))
4934 if (BITARRAY_TEST(cases_seen, i) == 0)
4935 warning ("enumeration value `%s' not handled in switch",
4936 IDENTIFIER_POINTER (TREE_PURPOSE (v)));
4942 /* Now we go the other way around; we warn if there are case
4943 expressions that don't correspond to enumerators. This can
4944 occur since C and C++ don't enforce type-checking of
4945 assignments to enumeration variables. */
4947 if (case_stack->data.case_stmt.case_list
4948 && case_stack->data.case_stmt.case_list->left)
4949 case_stack->data.case_stmt.case_list
4950 = case_tree2list (case_stack->data.case_stmt.case_list, 0);
4952 for (n = case_stack->data.case_stmt.case_list; n; n = n->right)
4954 for (chain = TYPE_VALUES (type);
4955 chain && !tree_int_cst_equal (n->low, TREE_VALUE (chain));
4956 chain = TREE_CHAIN (chain))
4961 if (TYPE_NAME (type) == 0)
4962 warning ("case value `%ld' not in enumerated type",
4963 (long) TREE_INT_CST_LOW (n->low));
4965 warning ("case value `%ld' not in enumerated type `%s'",
4966 (long) TREE_INT_CST_LOW (n->low),
4967 IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
4970 : DECL_NAME (TYPE_NAME (type))));
4972 if (!tree_int_cst_equal (n->low, n->high))
4974 for (chain = TYPE_VALUES (type);
4975 chain && !tree_int_cst_equal (n->high, TREE_VALUE (chain));
4976 chain = TREE_CHAIN (chain))
4981 if (TYPE_NAME (type) == 0)
4982 warning ("case value `%ld' not in enumerated type",
4983 (long) TREE_INT_CST_LOW (n->high));
4985 warning ("case value `%ld' not in enumerated type `%s'",
4986 (long) TREE_INT_CST_LOW (n->high),
4987 IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
4990 : DECL_NAME (TYPE_NAME (type))));
4996 /* ??? This optimization is disabled because it causes valid programs to
4997 fail. ANSI C does not guarantee that an expression with enum type
4998 will have a value that is the same as one of the enumeration literals. */
5000 /* If all values were found as case labels, make one of them the default
5001 label. Thus, this switch will never fall through. We arbitrarily pick
5002 the last one to make the default since this is likely the most
5003 efficient choice. */
5007 for (l = &case_stack->data.case_stmt.case_list;
5012 case_stack->data.case_stmt.default_label = (*l)->code_label;
5019 /* Terminate a case (Pascal) or switch (C) statement
5020 in which ORIG_INDEX is the expression to be tested.
5021 Generate the code to test it and jump to the right place. */
5024 expand_end_case (orig_index)
5027 tree minval, maxval, range, orig_minval;
5028 rtx default_label = 0;
5029 register struct case_node *n;
5037 register struct nesting *thiscase = case_stack;
5038 tree index_expr, index_type;
5041 table_label = gen_label_rtx ();
5042 index_expr = thiscase->data.case_stmt.index_expr;
5043 index_type = TREE_TYPE (index_expr);
5044 unsignedp = TREE_UNSIGNED (index_type);
5046 do_pending_stack_adjust ();
5048 /* This might get an spurious warning in the presence of a syntax error;
5049 it could be fixed by moving the call to check_seenlabel after the
5050 check for error_mark_node, and copying the code of check_seenlabel that
5051 deals with case_stack->data.case_stmt.line_number_status /
5052 restore_line_number_status in front of the call to end_cleanup_deferral;
5053 However, this might miss some useful warnings in the presence of
5054 non-syntax errors. */
5057 /* An ERROR_MARK occurs for various reasons including invalid data type. */
5058 if (index_type != error_mark_node)
5060 /* If switch expression was an enumerated type, check that all
5061 enumeration literals are covered by the cases.
5062 No sense trying this if there's a default case, however. */
5064 if (!thiscase->data.case_stmt.default_label
5065 && TREE_CODE (TREE_TYPE (orig_index)) == ENUMERAL_TYPE
5066 && TREE_CODE (index_expr) != INTEGER_CST)
5067 check_for_full_enumeration_handling (TREE_TYPE (orig_index));
5069 /* If we don't have a default-label, create one here,
5070 after the body of the switch. */
5071 if (thiscase->data.case_stmt.default_label == 0)
5073 thiscase->data.case_stmt.default_label
5074 = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
5075 expand_label (thiscase->data.case_stmt.default_label);
5077 default_label = label_rtx (thiscase->data.case_stmt.default_label);
5079 before_case = get_last_insn ();
5081 if (thiscase->data.case_stmt.case_list
5082 && thiscase->data.case_stmt.case_list->left)
5083 thiscase->data.case_stmt.case_list
5084 = case_tree2list(thiscase->data.case_stmt.case_list, 0);
5086 /* Simplify the case-list before we count it. */
5087 group_case_nodes (thiscase->data.case_stmt.case_list);
5089 /* Get upper and lower bounds of case values.
5090 Also convert all the case values to the index expr's data type. */
5093 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5095 /* Check low and high label values are integers. */
5096 if (TREE_CODE (n->low) != INTEGER_CST)
5098 if (TREE_CODE (n->high) != INTEGER_CST)
5101 n->low = convert (index_type, n->low);
5102 n->high = convert (index_type, n->high);
5104 /* Count the elements and track the largest and smallest
5105 of them (treating them as signed even if they are not). */
5113 if (INT_CST_LT (n->low, minval))
5115 if (INT_CST_LT (maxval, n->high))
5118 /* A range counts double, since it requires two compares. */
5119 if (! tree_int_cst_equal (n->low, n->high))
5123 orig_minval = minval;
5125 /* Compute span of values. */
5127 range = fold (build (MINUS_EXPR, index_type, maxval, minval));
5129 end_cleanup_deferral ();
5133 expand_expr (index_expr, const0_rtx, VOIDmode, 0);
5135 emit_jump (default_label);
5138 /* If range of values is much bigger than number of values,
5139 make a sequence of conditional branches instead of a dispatch.
5140 If the switch-index is a constant, do it this way
5141 because we can optimize it. */
5143 #ifndef CASE_VALUES_THRESHOLD
5145 #define CASE_VALUES_THRESHOLD (HAVE_casesi ? 4 : 5)
5147 /* If machine does not have a case insn that compares the
5148 bounds, this means extra overhead for dispatch tables
5149 which raises the threshold for using them. */
5150 #define CASE_VALUES_THRESHOLD 5
5151 #endif /* HAVE_casesi */
5152 #endif /* CASE_VALUES_THRESHOLD */
5154 else if (TREE_INT_CST_HIGH (range) != 0
5155 || count < (unsigned int) CASE_VALUES_THRESHOLD
5156 || ((unsigned HOST_WIDE_INT) (TREE_INT_CST_LOW (range))
5158 #ifndef ASM_OUTPUT_ADDR_DIFF_ELT
5161 || TREE_CODE (index_expr) == INTEGER_CST
5162 /* These will reduce to a constant. */
5163 || (TREE_CODE (index_expr) == CALL_EXPR
5164 && TREE_CODE (TREE_OPERAND (index_expr, 0)) == ADDR_EXPR
5165 && TREE_CODE (TREE_OPERAND (TREE_OPERAND (index_expr, 0), 0)) == FUNCTION_DECL
5166 && DECL_FUNCTION_CODE (TREE_OPERAND (TREE_OPERAND (index_expr, 0), 0)) == BUILT_IN_CLASSIFY_TYPE)
5167 || (TREE_CODE (index_expr) == COMPOUND_EXPR
5168 && TREE_CODE (TREE_OPERAND (index_expr, 1)) == INTEGER_CST))
5170 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
5172 /* If the index is a short or char that we do not have
5173 an insn to handle comparisons directly, convert it to
5174 a full integer now, rather than letting each comparison
5175 generate the conversion. */
5177 if (GET_MODE_CLASS (GET_MODE (index)) == MODE_INT
5178 && (cmp_optab->handlers[(int) GET_MODE(index)].insn_code
5179 == CODE_FOR_nothing))
5181 enum machine_mode wider_mode;
5182 for (wider_mode = GET_MODE (index); wider_mode != VOIDmode;
5183 wider_mode = GET_MODE_WIDER_MODE (wider_mode))
5184 if (cmp_optab->handlers[(int) wider_mode].insn_code
5185 != CODE_FOR_nothing)
5187 index = convert_to_mode (wider_mode, index, unsignedp);
5193 do_pending_stack_adjust ();
5195 index = protect_from_queue (index, 0);
5196 if (GET_CODE (index) == MEM)
5197 index = copy_to_reg (index);
5198 if (GET_CODE (index) == CONST_INT
5199 || TREE_CODE (index_expr) == INTEGER_CST)
5201 /* Make a tree node with the proper constant value
5202 if we don't already have one. */
5203 if (TREE_CODE (index_expr) != INTEGER_CST)
5206 = build_int_2 (INTVAL (index),
5207 unsignedp || INTVAL (index) >= 0 ? 0 : -1);
5208 index_expr = convert (index_type, index_expr);
5211 /* For constant index expressions we need only
5212 issue a unconditional branch to the appropriate
5213 target code. The job of removing any unreachable
5214 code is left to the optimisation phase if the
5215 "-O" option is specified. */
5216 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5217 if (! tree_int_cst_lt (index_expr, n->low)
5218 && ! tree_int_cst_lt (n->high, index_expr))
5222 emit_jump (label_rtx (n->code_label));
5224 emit_jump (default_label);
5228 /* If the index expression is not constant we generate
5229 a binary decision tree to select the appropriate
5230 target code. This is done as follows:
5232 The list of cases is rearranged into a binary tree,
5233 nearly optimal assuming equal probability for each case.
5235 The tree is transformed into RTL, eliminating
5236 redundant test conditions at the same time.
5238 If program flow could reach the end of the
5239 decision tree an unconditional jump to the
5240 default code is emitted. */
5243 = (TREE_CODE (TREE_TYPE (orig_index)) != ENUMERAL_TYPE
5244 && estimate_case_costs (thiscase->data.case_stmt.case_list));
5245 balance_case_nodes (&thiscase->data.case_stmt.case_list,
5247 emit_case_nodes (index, thiscase->data.case_stmt.case_list,
5248 default_label, index_type);
5249 emit_jump_if_reachable (default_label);
5258 enum machine_mode index_mode = SImode;
5259 int index_bits = GET_MODE_BITSIZE (index_mode);
5261 enum machine_mode op_mode;
5263 /* Convert the index to SImode. */
5264 if (GET_MODE_BITSIZE (TYPE_MODE (index_type))
5265 > GET_MODE_BITSIZE (index_mode))
5267 enum machine_mode omode = TYPE_MODE (index_type);
5268 rtx rangertx = expand_expr (range, NULL_RTX, VOIDmode, 0);
5270 /* We must handle the endpoints in the original mode. */
5271 index_expr = build (MINUS_EXPR, index_type,
5272 index_expr, minval);
5273 minval = integer_zero_node;
5274 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
5275 emit_cmp_and_jump_insns (rangertx, index, LTU, NULL_RTX,
5276 omode, 1, 0, default_label);
5277 /* Now we can safely truncate. */
5278 index = convert_to_mode (index_mode, index, 0);
5282 if (TYPE_MODE (index_type) != index_mode)
5284 index_expr = convert (type_for_size (index_bits, 0),
5286 index_type = TREE_TYPE (index_expr);
5289 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
5292 index = protect_from_queue (index, 0);
5293 do_pending_stack_adjust ();
5295 op_mode = insn_operand_mode[(int)CODE_FOR_casesi][0];
5296 if (! (*insn_operand_predicate[(int)CODE_FOR_casesi][0])
5298 index = copy_to_mode_reg (op_mode, index);
5300 op1 = expand_expr (minval, NULL_RTX, VOIDmode, 0);
5302 op_mode = insn_operand_mode[(int)CODE_FOR_casesi][1];
5303 if (! (*insn_operand_predicate[(int)CODE_FOR_casesi][1])
5305 op1 = copy_to_mode_reg (op_mode, op1);
5307 op2 = expand_expr (range, NULL_RTX, VOIDmode, 0);
5309 op_mode = insn_operand_mode[(int)CODE_FOR_casesi][2];
5310 if (! (*insn_operand_predicate[(int)CODE_FOR_casesi][2])
5312 op2 = copy_to_mode_reg (op_mode, op2);
5314 emit_jump_insn (gen_casesi (index, op1, op2,
5315 table_label, default_label));
5319 #ifdef HAVE_tablejump
5320 if (! win && HAVE_tablejump)
5322 index_expr = convert (thiscase->data.case_stmt.nominal_type,
5323 fold (build (MINUS_EXPR, index_type,
5324 index_expr, minval)));
5325 index_type = TREE_TYPE (index_expr);
5326 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
5328 index = protect_from_queue (index, 0);
5329 do_pending_stack_adjust ();
5331 do_tablejump (index, TYPE_MODE (index_type),
5332 expand_expr (range, NULL_RTX, VOIDmode, 0),
5333 table_label, default_label);
5340 /* Get table of labels to jump to, in order of case index. */
5342 ncases = TREE_INT_CST_LOW (range) + 1;
5343 labelvec = (rtx *) alloca (ncases * sizeof (rtx));
5344 bzero ((char *) labelvec, ncases * sizeof (rtx));
5346 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5348 register HOST_WIDE_INT i
5349 = TREE_INT_CST_LOW (n->low) - TREE_INT_CST_LOW (orig_minval);
5354 = gen_rtx_LABEL_REF (Pmode, label_rtx (n->code_label));
5355 if (i + TREE_INT_CST_LOW (orig_minval)
5356 == TREE_INT_CST_LOW (n->high))
5362 /* Fill in the gaps with the default. */
5363 for (i = 0; i < ncases; i++)
5364 if (labelvec[i] == 0)
5365 labelvec[i] = gen_rtx_LABEL_REF (Pmode, default_label);
5367 /* Output the table */
5368 emit_label (table_label);
5370 if (CASE_VECTOR_PC_RELATIVE || flag_pic)
5371 emit_jump_insn (gen_rtx_ADDR_DIFF_VEC (CASE_VECTOR_MODE,
5372 gen_rtx_LABEL_REF (Pmode, table_label),
5373 gen_rtvec_v (ncases, labelvec),
5374 const0_rtx, const0_rtx, 0));
5376 emit_jump_insn (gen_rtx_ADDR_VEC (CASE_VECTOR_MODE,
5377 gen_rtvec_v (ncases, labelvec)));
5379 /* If the case insn drops through the table,
5380 after the table we must jump to the default-label.
5381 Otherwise record no drop-through after the table. */
5382 #ifdef CASE_DROPS_THROUGH
5383 emit_jump (default_label);
5389 before_case = squeeze_notes (NEXT_INSN (before_case), get_last_insn ());
5390 reorder_insns (before_case, get_last_insn (),
5391 thiscase->data.case_stmt.start);
5394 end_cleanup_deferral ();
5396 if (thiscase->exit_label)
5397 emit_label (thiscase->exit_label);
5399 POPSTACK (case_stack);
5404 /* Convert the tree NODE into a list linked by the right field, with the left
5405 field zeroed. RIGHT is used for recursion; it is a list to be placed
5406 rightmost in the resulting list. */
5408 static struct case_node *
5409 case_tree2list (node, right)
5410 struct case_node *node, *right;
5412 struct case_node *left;
5415 right = case_tree2list (node->right, right);
5417 node->right = right;
5418 if ((left = node->left))
5421 return case_tree2list (left, node);
5427 /* Generate code to jump to LABEL if OP1 and OP2 are equal. */
5430 do_jump_if_equal (op1, op2, label, unsignedp)
5431 rtx op1, op2, label;
5434 if (GET_CODE (op1) == CONST_INT
5435 && GET_CODE (op2) == CONST_INT)
5437 if (INTVAL (op1) == INTVAL (op2))
5442 enum machine_mode mode = GET_MODE (op1);
5443 if (mode == VOIDmode)
5444 mode = GET_MODE (op2);
5445 emit_cmp_and_jump_insns (op1, op2, EQ, NULL_RTX, mode, unsignedp,
5450 /* Not all case values are encountered equally. This function
5451 uses a heuristic to weight case labels, in cases where that
5452 looks like a reasonable thing to do.
5454 Right now, all we try to guess is text, and we establish the
5457 chars above space: 16
5466 If we find any cases in the switch that are not either -1 or in the range
5467 of valid ASCII characters, or are control characters other than those
5468 commonly used with "\", don't treat this switch scanning text.
5470 Return 1 if these nodes are suitable for cost estimation, otherwise
5474 estimate_case_costs (node)
5477 tree min_ascii = build_int_2 (-1, -1);
5478 tree max_ascii = convert (TREE_TYPE (node->high), build_int_2 (127, 0));
5482 /* If we haven't already made the cost table, make it now. Note that the
5483 lower bound of the table is -1, not zero. */
5485 if (cost_table == NULL)
5487 cost_table = ((short *) xmalloc (129 * sizeof (short))) + 1;
5488 bzero ((char *) (cost_table - 1), 129 * sizeof (short));
5490 for (i = 0; i < 128; i++)
5494 else if (ISPUNCT (i))
5496 else if (ISCNTRL (i))
5500 cost_table[' '] = 8;
5501 cost_table['\t'] = 4;
5502 cost_table['\0'] = 4;
5503 cost_table['\n'] = 2;
5504 cost_table['\f'] = 1;
5505 cost_table['\v'] = 1;
5506 cost_table['\b'] = 1;
5509 /* See if all the case expressions look like text. It is text if the
5510 constant is >= -1 and the highest constant is <= 127. Do all comparisons
5511 as signed arithmetic since we don't want to ever access cost_table with a
5512 value less than -1. Also check that none of the constants in a range
5513 are strange control characters. */
5515 for (n = node; n; n = n->right)
5517 if ((INT_CST_LT (n->low, min_ascii)) || INT_CST_LT (max_ascii, n->high))
5520 for (i = TREE_INT_CST_LOW (n->low); i <= TREE_INT_CST_LOW (n->high); i++)
5521 if (cost_table[i] < 0)
5525 /* All interesting values are within the range of interesting
5526 ASCII characters. */
5530 /* Scan an ordered list of case nodes
5531 combining those with consecutive values or ranges.
5533 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
5536 group_case_nodes (head)
5539 case_node_ptr node = head;
5543 rtx lb = next_real_insn (label_rtx (node->code_label));
5545 case_node_ptr np = node;
5547 /* Try to group the successors of NODE with NODE. */
5548 while (((np = np->right) != 0)
5549 /* Do they jump to the same place? */
5550 && ((lb2 = next_real_insn (label_rtx (np->code_label))) == lb
5551 || (lb != 0 && lb2 != 0
5552 && simplejump_p (lb)
5553 && simplejump_p (lb2)
5554 && rtx_equal_p (SET_SRC (PATTERN (lb)),
5555 SET_SRC (PATTERN (lb2)))))
5556 /* Are their ranges consecutive? */
5557 && tree_int_cst_equal (np->low,
5558 fold (build (PLUS_EXPR,
5559 TREE_TYPE (node->high),
5562 /* An overflow is not consecutive. */
5563 && tree_int_cst_lt (node->high,
5564 fold (build (PLUS_EXPR,
5565 TREE_TYPE (node->high),
5567 integer_one_node))))
5569 node->high = np->high;
5571 /* NP is the first node after NODE which can't be grouped with it.
5572 Delete the nodes in between, and move on to that node. */
5578 /* Take an ordered list of case nodes
5579 and transform them into a near optimal binary tree,
5580 on the assumption that any target code selection value is as
5581 likely as any other.
5583 The transformation is performed by splitting the ordered
5584 list into two equal sections plus a pivot. The parts are
5585 then attached to the pivot as left and right branches. Each
5586 branch is then transformed recursively. */
5589 balance_case_nodes (head, parent)
5590 case_node_ptr *head;
5591 case_node_ptr parent;
5593 register case_node_ptr np;
5601 register case_node_ptr *npp;
5604 /* Count the number of entries on branch. Also count the ranges. */
5608 if (!tree_int_cst_equal (np->low, np->high))
5612 cost += cost_table[TREE_INT_CST_LOW (np->high)];
5616 cost += cost_table[TREE_INT_CST_LOW (np->low)];
5624 /* Split this list if it is long enough for that to help. */
5629 /* Find the place in the list that bisects the list's total cost,
5630 Here I gets half the total cost. */
5635 /* Skip nodes while their cost does not reach that amount. */
5636 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
5637 i -= cost_table[TREE_INT_CST_LOW ((*npp)->high)];
5638 i -= cost_table[TREE_INT_CST_LOW ((*npp)->low)];
5641 npp = &(*npp)->right;
5646 /* Leave this branch lopsided, but optimize left-hand
5647 side and fill in `parent' fields for right-hand side. */
5649 np->parent = parent;
5650 balance_case_nodes (&np->left, np);
5651 for (; np->right; np = np->right)
5652 np->right->parent = np;
5656 /* If there are just three nodes, split at the middle one. */
5658 npp = &(*npp)->right;
5661 /* Find the place in the list that bisects the list's total cost,
5662 where ranges count as 2.
5663 Here I gets half the total cost. */
5664 i = (i + ranges + 1) / 2;
5667 /* Skip nodes while their cost does not reach that amount. */
5668 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
5673 npp = &(*npp)->right;
5678 np->parent = parent;
5681 /* Optimize each of the two split parts. */
5682 balance_case_nodes (&np->left, np);
5683 balance_case_nodes (&np->right, np);
5687 /* Else leave this branch as one level,
5688 but fill in `parent' fields. */
5690 np->parent = parent;
5691 for (; np->right; np = np->right)
5692 np->right->parent = np;
5697 /* Search the parent sections of the case node tree
5698 to see if a test for the lower bound of NODE would be redundant.
5699 INDEX_TYPE is the type of the index expression.
5701 The instructions to generate the case decision tree are
5702 output in the same order as nodes are processed so it is
5703 known that if a parent node checks the range of the current
5704 node minus one that the current node is bounded at its lower
5705 span. Thus the test would be redundant. */
5708 node_has_low_bound (node, index_type)
5713 case_node_ptr pnode;
5715 /* If the lower bound of this node is the lowest value in the index type,
5716 we need not test it. */
5718 if (tree_int_cst_equal (node->low, TYPE_MIN_VALUE (index_type)))
5721 /* If this node has a left branch, the value at the left must be less
5722 than that at this node, so it cannot be bounded at the bottom and
5723 we need not bother testing any further. */
5728 low_minus_one = fold (build (MINUS_EXPR, TREE_TYPE (node->low),
5729 node->low, integer_one_node));
5731 /* If the subtraction above overflowed, we can't verify anything.
5732 Otherwise, look for a parent that tests our value - 1. */
5734 if (! tree_int_cst_lt (low_minus_one, node->low))
5737 for (pnode = node->parent; pnode; pnode = pnode->parent)
5738 if (tree_int_cst_equal (low_minus_one, pnode->high))
5744 /* Search the parent sections of the case node tree
5745 to see if a test for the upper bound of NODE would be redundant.
5746 INDEX_TYPE is the type of the index expression.
5748 The instructions to generate the case decision tree are
5749 output in the same order as nodes are processed so it is
5750 known that if a parent node checks the range of the current
5751 node plus one that the current node is bounded at its upper
5752 span. Thus the test would be redundant. */
5755 node_has_high_bound (node, index_type)
5760 case_node_ptr pnode;
5762 /* If there is no upper bound, obviously no test is needed. */
5764 if (TYPE_MAX_VALUE (index_type) == NULL)
5767 /* If the upper bound of this node is the highest value in the type
5768 of the index expression, we need not test against it. */
5770 if (tree_int_cst_equal (node->high, TYPE_MAX_VALUE (index_type)))
5773 /* If this node has a right branch, the value at the right must be greater
5774 than that at this node, so it cannot be bounded at the top and
5775 we need not bother testing any further. */
5780 high_plus_one = fold (build (PLUS_EXPR, TREE_TYPE (node->high),
5781 node->high, integer_one_node));
5783 /* If the addition above overflowed, we can't verify anything.
5784 Otherwise, look for a parent that tests our value + 1. */
5786 if (! tree_int_cst_lt (node->high, high_plus_one))
5789 for (pnode = node->parent; pnode; pnode = pnode->parent)
5790 if (tree_int_cst_equal (high_plus_one, pnode->low))
5796 /* Search the parent sections of the
5797 case node tree to see if both tests for the upper and lower
5798 bounds of NODE would be redundant. */
5801 node_is_bounded (node, index_type)
5805 return (node_has_low_bound (node, index_type)
5806 && node_has_high_bound (node, index_type));
5809 /* Emit an unconditional jump to LABEL unless it would be dead code. */
5812 emit_jump_if_reachable (label)
5815 if (GET_CODE (get_last_insn ()) != BARRIER)
5819 /* Emit step-by-step code to select a case for the value of INDEX.
5820 The thus generated decision tree follows the form of the
5821 case-node binary tree NODE, whose nodes represent test conditions.
5822 INDEX_TYPE is the type of the index of the switch.
5824 Care is taken to prune redundant tests from the decision tree
5825 by detecting any boundary conditions already checked by
5826 emitted rtx. (See node_has_high_bound, node_has_low_bound
5827 and node_is_bounded, above.)
5829 Where the test conditions can be shown to be redundant we emit
5830 an unconditional jump to the target code. As a further
5831 optimization, the subordinates of a tree node are examined to
5832 check for bounded nodes. In this case conditional and/or
5833 unconditional jumps as a result of the boundary check for the
5834 current node are arranged to target the subordinates associated
5835 code for out of bound conditions on the current node.
5837 We can assume that when control reaches the code generated here,
5838 the index value has already been compared with the parents
5839 of this node, and determined to be on the same side of each parent
5840 as this node is. Thus, if this node tests for the value 51,
5841 and a parent tested for 52, we don't need to consider
5842 the possibility of a value greater than 51. If another parent
5843 tests for the value 50, then this node need not test anything. */
5846 emit_case_nodes (index, node, default_label, index_type)
5852 /* If INDEX has an unsigned type, we must make unsigned branches. */
5853 int unsignedp = TREE_UNSIGNED (index_type);
5854 typedef rtx rtx_fn ();
5855 enum machine_mode mode = GET_MODE (index);
5857 /* See if our parents have already tested everything for us.
5858 If they have, emit an unconditional jump for this node. */
5859 if (node_is_bounded (node, index_type))
5860 emit_jump (label_rtx (node->code_label));
5862 else if (tree_int_cst_equal (node->low, node->high))
5864 /* Node is single valued. First see if the index expression matches
5865 this node and then check our children, if any. */
5867 do_jump_if_equal (index, expand_expr (node->low, NULL_RTX, VOIDmode, 0),
5868 label_rtx (node->code_label), unsignedp);
5870 if (node->right != 0 && node->left != 0)
5872 /* This node has children on both sides.
5873 Dispatch to one side or the other
5874 by comparing the index value with this node's value.
5875 If one subtree is bounded, check that one first,
5876 so we can avoid real branches in the tree. */
5878 if (node_is_bounded (node->right, index_type))
5880 emit_cmp_and_jump_insns (index, expand_expr (node->high, NULL_RTX,
5882 GT, NULL_RTX, mode, unsignedp, 0,
5883 label_rtx (node->right->code_label));
5884 emit_case_nodes (index, node->left, default_label, index_type);
5887 else if (node_is_bounded (node->left, index_type))
5889 emit_cmp_and_jump_insns (index, expand_expr (node->high, NULL_RTX,
5891 LT, NULL_RTX, mode, unsignedp, 0,
5892 label_rtx (node->left->code_label));
5893 emit_case_nodes (index, node->right, default_label, index_type);
5898 /* Neither node is bounded. First distinguish the two sides;
5899 then emit the code for one side at a time. */
5902 = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
5904 /* See if the value is on the right. */
5905 emit_cmp_and_jump_insns (index, expand_expr (node->high, NULL_RTX,
5907 GT, NULL_RTX, mode, unsignedp, 0,
5908 label_rtx (test_label));
5910 /* Value must be on the left.
5911 Handle the left-hand subtree. */
5912 emit_case_nodes (index, node->left, default_label, index_type);
5913 /* If left-hand subtree does nothing,
5915 emit_jump_if_reachable (default_label);
5917 /* Code branches here for the right-hand subtree. */
5918 expand_label (test_label);
5919 emit_case_nodes (index, node->right, default_label, index_type);
5923 else if (node->right != 0 && node->left == 0)
5925 /* Here we have a right child but no left so we issue conditional
5926 branch to default and process the right child.
5928 Omit the conditional branch to default if we it avoid only one
5929 right child; it costs too much space to save so little time. */
5931 if (node->right->right || node->right->left
5932 || !tree_int_cst_equal (node->right->low, node->right->high))
5934 if (!node_has_low_bound (node, index_type))
5936 emit_cmp_and_jump_insns (index, expand_expr (node->high,
5939 LT, NULL_RTX, mode, unsignedp, 0,
5943 emit_case_nodes (index, node->right, default_label, index_type);
5946 /* We cannot process node->right normally
5947 since we haven't ruled out the numbers less than
5948 this node's value. So handle node->right explicitly. */
5949 do_jump_if_equal (index,
5950 expand_expr (node->right->low, NULL_RTX,
5952 label_rtx (node->right->code_label), unsignedp);
5955 else if (node->right == 0 && node->left != 0)
5957 /* Just one subtree, on the left. */
5959 #if 0 /* The following code and comment were formerly part
5960 of the condition here, but they didn't work
5961 and I don't understand what the idea was. -- rms. */
5962 /* If our "most probable entry" is less probable
5963 than the default label, emit a jump to
5964 the default label using condition codes
5965 already lying around. With no right branch,
5966 a branch-greater-than will get us to the default
5969 && cost_table[TREE_INT_CST_LOW (node->high)] < 12)
5972 if (node->left->left || node->left->right
5973 || !tree_int_cst_equal (node->left->low, node->left->high))
5975 if (!node_has_high_bound (node, index_type))
5977 emit_cmp_and_jump_insns (index, expand_expr (node->high,
5980 GT, NULL_RTX, mode, unsignedp, 0,
5984 emit_case_nodes (index, node->left, default_label, index_type);
5987 /* We cannot process node->left normally
5988 since we haven't ruled out the numbers less than
5989 this node's value. So handle node->left explicitly. */
5990 do_jump_if_equal (index,
5991 expand_expr (node->left->low, NULL_RTX,
5993 label_rtx (node->left->code_label), unsignedp);
5998 /* Node is a range. These cases are very similar to those for a single
5999 value, except that we do not start by testing whether this node
6000 is the one to branch to. */
6002 if (node->right != 0 && node->left != 0)
6004 /* Node has subtrees on both sides.
6005 If the right-hand subtree is bounded,
6006 test for it first, since we can go straight there.
6007 Otherwise, we need to make a branch in the control structure,
6008 then handle the two subtrees. */
6009 tree test_label = 0;
6012 if (node_is_bounded (node->right, index_type))
6013 /* Right hand node is fully bounded so we can eliminate any
6014 testing and branch directly to the target code. */
6015 emit_cmp_and_jump_insns (index, expand_expr (node->high, NULL_RTX,
6017 GT, NULL_RTX, mode, unsignedp, 0,
6018 label_rtx (node->right->code_label));
6021 /* Right hand node requires testing.
6022 Branch to a label where we will handle it later. */
6024 test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
6025 emit_cmp_and_jump_insns (index, expand_expr (node->high, NULL_RTX,
6027 GT, NULL_RTX, mode, unsignedp, 0,
6028 label_rtx (test_label));
6031 /* Value belongs to this node or to the left-hand subtree. */
6033 emit_cmp_and_jump_insns (index, expand_expr (node->low, NULL_RTX,
6035 GE, NULL_RTX, mode, unsignedp, 0,
6036 label_rtx (node->code_label));
6038 /* Handle the left-hand subtree. */
6039 emit_case_nodes (index, node->left, default_label, index_type);
6041 /* If right node had to be handled later, do that now. */
6045 /* If the left-hand subtree fell through,
6046 don't let it fall into the right-hand subtree. */
6047 emit_jump_if_reachable (default_label);
6049 expand_label (test_label);
6050 emit_case_nodes (index, node->right, default_label, index_type);
6054 else if (node->right != 0 && node->left == 0)
6056 /* Deal with values to the left of this node,
6057 if they are possible. */
6058 if (!node_has_low_bound (node, index_type))
6060 emit_cmp_and_jump_insns (index, expand_expr (node->low, NULL_RTX,
6062 LT, NULL_RTX, mode, unsignedp, 0,
6066 /* Value belongs to this node or to the right-hand subtree. */
6068 emit_cmp_and_jump_insns (index, expand_expr (node->high, NULL_RTX,
6070 LE, NULL_RTX, mode, unsignedp, 0,
6071 label_rtx (node->code_label));
6073 emit_case_nodes (index, node->right, default_label, index_type);
6076 else if (node->right == 0 && node->left != 0)
6078 /* Deal with values to the right of this node,
6079 if they are possible. */
6080 if (!node_has_high_bound (node, index_type))
6082 emit_cmp_and_jump_insns (index, expand_expr (node->high, NULL_RTX,
6084 GT, NULL_RTX, mode, unsignedp, 0,
6088 /* Value belongs to this node or to the left-hand subtree. */
6090 emit_cmp_and_jump_insns (index, expand_expr (node->low, NULL_RTX,
6092 GE, NULL_RTX, mode, unsignedp, 0,
6093 label_rtx (node->code_label));
6095 emit_case_nodes (index, node->left, default_label, index_type);
6100 /* Node has no children so we check low and high bounds to remove
6101 redundant tests. Only one of the bounds can exist,
6102 since otherwise this node is bounded--a case tested already. */
6104 if (!node_has_high_bound (node, index_type))
6106 emit_cmp_and_jump_insns (index, expand_expr (node->high, NULL_RTX,
6108 GT, NULL_RTX, mode, unsignedp, 0,
6112 if (!node_has_low_bound (node, index_type))
6114 emit_cmp_and_jump_insns (index, expand_expr (node->low, NULL_RTX,
6116 LT, NULL_RTX, mode, unsignedp, 0,
6120 emit_jump (label_rtx (node->code_label));
6125 /* These routines are used by the loop unrolling code. They copy BLOCK trees
6126 so that the debugging info will be correct for the unrolled loop. */
6128 /* Indexed by block number, contains a pointer to the N'th block node.
6130 Allocated by the call to identify_blocks, then released after the call
6131 to reorder_blocks in the function unroll_block_trees. */
6133 static tree *block_vector;
6136 find_loop_tree_blocks ()
6138 tree block = DECL_INITIAL (current_function_decl);
6140 block_vector = identify_blocks (block, get_insns ());
6144 unroll_block_trees ()
6146 tree block = DECL_INITIAL (current_function_decl);
6148 reorder_blocks (block_vector, block, get_insns ());
6150 /* Release any memory allocated by identify_blocks. */
6152 free (block_vector);