1 /* Expands front end tree to back end RTL for GNU C-Compiler
2 Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997,
3 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
22 /* This file handles the generation of rtl code from tree structure
23 above the level of expressions, using subroutines in exp*.c and emit-rtl.c.
24 It also creates the rtl expressions for parameters and auto variables
25 and has full responsibility for allocating stack slots.
27 The functions whose names start with `expand_' are called by the
28 parser to generate RTL instructions for various kinds of constructs.
30 Some control and binding constructs require calling several such
31 functions at different times. For example, a simple if-then
32 is expanded by calling `expand_start_cond' (with the condition-expression
33 as argument) before parsing the then-clause and calling `expand_end_cond'
34 after parsing the then-clause. */
45 #include "insn-config.h"
48 #include "hard-reg-set.h"
57 #define obstack_chunk_alloc xmalloc
58 #define obstack_chunk_free free
59 struct obstack stmt_obstack;
61 /* Assume that case vectors are not pc-relative. */
62 #ifndef CASE_VECTOR_PC_RELATIVE
63 #define CASE_VECTOR_PC_RELATIVE 0
66 /* Functions and data structures for expanding case statements. */
68 /* Case label structure, used to hold info on labels within case
69 statements. We handle "range" labels; for a single-value label
70 as in C, the high and low limits are the same.
72 An AVL tree of case nodes is initially created, and later transformed
73 to a list linked via the RIGHT fields in the nodes. Nodes with
74 higher case values are later in the list.
76 Switch statements can be output in one of two forms. A branch table
77 is used if there are more than a few labels and the labels are dense
78 within the range between the smallest and largest case value. If a
79 branch table is used, no further manipulations are done with the case
82 The alternative to the use of a branch table is to generate a series
83 of compare and jump insns. When that is done, we use the LEFT, RIGHT,
84 and PARENT fields to hold a binary tree. Initially the tree is
85 totally unbalanced, with everything on the right. We balance the tree
86 with nodes on the left having lower case values than the parent
87 and nodes on the right having higher values. We then output the tree
92 struct case_node *left; /* Left son in binary tree */
93 struct case_node *right; /* Right son in binary tree; also node chain */
94 struct case_node *parent; /* Parent of node in binary tree */
95 tree low; /* Lowest index value for this label */
96 tree high; /* Highest index value for this label */
97 tree code_label; /* Label to jump to when node matches */
101 typedef struct case_node case_node;
102 typedef struct case_node *case_node_ptr;
104 /* These are used by estimate_case_costs and balance_case_nodes. */
106 /* This must be a signed type, and non-ANSI compilers lack signed char. */
107 static short cost_table_[129];
108 static int use_cost_table;
109 static int cost_table_initialized;
111 /* Special care is needed because we allow -1, but TREE_INT_CST_LOW
113 #define COST_TABLE(I) cost_table_[(unsigned HOST_WIDE_INT)((I) + 1)]
115 /* Stack of control and binding constructs we are currently inside.
117 These constructs begin when you call `expand_start_WHATEVER'
118 and end when you call `expand_end_WHATEVER'. This stack records
119 info about how the construct began that tells the end-function
120 what to do. It also may provide information about the construct
121 to alter the behavior of other constructs within the body.
122 For example, they may affect the behavior of C `break' and `continue'.
124 Each construct gets one `struct nesting' object.
125 All of these objects are chained through the `all' field.
126 `nesting_stack' points to the first object (innermost construct).
127 The position of an entry on `nesting_stack' is in its `depth' field.
129 Each type of construct has its own individual stack.
130 For example, loops have `loop_stack'. Each object points to the
131 next object of the same type through the `next' field.
133 Some constructs are visible to `break' exit-statements and others
134 are not. Which constructs are visible depends on the language.
135 Therefore, the data structure allows each construct to be visible
136 or not, according to the args given when the construct is started.
137 The construct is visible if the `exit_label' field is non-null.
138 In that case, the value should be a CODE_LABEL rtx. */
143 struct nesting *next;
148 /* For conds (if-then and if-then-else statements). */
151 /* Label for the end of the if construct.
152 There is none if EXITFLAG was not set
153 and no `else' has been seen yet. */
155 /* Label for the end of this alternative.
156 This may be the end of the if or the next else/elseif. */
162 /* Label at the top of the loop; place to loop back to. */
164 /* Label at the end of the whole construct. */
166 /* Label before a jump that branches to the end of the whole
167 construct. This is where destructors go if any. */
169 /* Label for `continue' statement to jump to;
170 this is in front of the stepper of the loop. */
173 /* For variable binding contours. */
176 /* Sequence number of this binding contour within the function,
177 in order of entry. */
178 int block_start_count;
179 /* Nonzero => value to restore stack to on exit. */
181 /* The NOTE that starts this contour.
182 Used by expand_goto to check whether the destination
183 is within each contour or not. */
185 /* Innermost containing binding contour that has a stack level. */
186 struct nesting *innermost_stack_block;
187 /* List of cleanups to be run on exit from this contour.
188 This is a list of expressions to be evaluated.
189 The TREE_PURPOSE of each link is the ..._DECL node
190 which the cleanup pertains to. */
192 /* List of cleanup-lists of blocks containing this block,
193 as they were at the locus where this block appears.
194 There is an element for each containing block,
195 ordered innermost containing block first.
196 The tail of this list can be 0,
197 if all remaining elements would be empty lists.
198 The element's TREE_VALUE is the cleanup-list of that block,
199 which may be null. */
201 /* Chain of labels defined inside this binding contour.
202 For contours that have stack levels or cleanups. */
203 struct label_chain *label_chain;
204 /* Number of function calls seen, as of start of this block. */
205 int n_function_calls;
206 /* Nonzero if this is associated with a EH region. */
207 int exception_region;
208 /* The saved target_temp_slot_level from our outer block.
209 We may reset target_temp_slot_level to be the level of
210 this block, if that is done, target_temp_slot_level
211 reverts to the saved target_temp_slot_level at the very
213 int block_target_temp_slot_level;
214 /* True if we are currently emitting insns in an area of
215 output code that is controlled by a conditional
216 expression. This is used by the cleanup handling code to
217 generate conditional cleanup actions. */
218 int conditional_code;
219 /* A place to move the start of the exception region for any
220 of the conditional cleanups, must be at the end or after
221 the start of the last unconditional cleanup, and before any
222 conditional branch points. */
223 rtx last_unconditional_cleanup;
224 /* When in a conditional context, this is the specific
225 cleanup list associated with last_unconditional_cleanup,
226 where we place the conditionalized cleanups. */
229 /* For switch (C) or case (Pascal) statements,
230 and also for dummies (see `expand_start_case_dummy'). */
233 /* The insn after which the case dispatch should finally
234 be emitted. Zero for a dummy. */
236 /* A list of case labels; it is first built as an AVL tree.
237 During expand_end_case, this is converted to a list, and may be
238 rearranged into a nearly balanced binary tree. */
239 struct case_node *case_list;
240 /* Label to jump to if no case matches. */
242 /* The expression to be dispatched on. */
244 /* Type that INDEX_EXPR should be converted to. */
246 /* Name of this kind of statement, for warnings. */
247 const char *printname;
248 /* Used to save no_line_numbers till we see the first case label.
249 We set this to -1 when we see the first case label in this
251 int line_number_status;
256 /* Allocate and return a new `struct nesting'. */
258 #define ALLOC_NESTING() \
259 (struct nesting *) obstack_alloc (&stmt_obstack, sizeof (struct nesting))
261 /* Pop the nesting stack element by element until we pop off
262 the element which is at the top of STACK.
263 Update all the other stacks, popping off elements from them
264 as we pop them from nesting_stack. */
266 #define POPSTACK(STACK) \
267 do { struct nesting *target = STACK; \
268 struct nesting *this; \
269 do { this = nesting_stack; \
270 if (loop_stack == this) \
271 loop_stack = loop_stack->next; \
272 if (cond_stack == this) \
273 cond_stack = cond_stack->next; \
274 if (block_stack == this) \
275 block_stack = block_stack->next; \
276 if (stack_block_stack == this) \
277 stack_block_stack = stack_block_stack->next; \
278 if (case_stack == this) \
279 case_stack = case_stack->next; \
280 nesting_depth = nesting_stack->depth - 1; \
281 nesting_stack = this->all; \
282 obstack_free (&stmt_obstack, this); } \
283 while (this != target); } while (0)
285 /* In some cases it is impossible to generate code for a forward goto
286 until the label definition is seen. This happens when it may be necessary
287 for the goto to reset the stack pointer: we don't yet know how to do that.
288 So expand_goto puts an entry on this fixup list.
289 Each time a binding contour that resets the stack is exited,
291 If the target label has now been defined, we can insert the proper code. */
295 /* Points to following fixup. */
296 struct goto_fixup *next;
297 /* Points to the insn before the jump insn.
298 If more code must be inserted, it goes after this insn. */
300 /* The LABEL_DECL that this jump is jumping to, or 0
301 for break, continue or return. */
303 /* The BLOCK for the place where this goto was found. */
305 /* The CODE_LABEL rtx that this is jumping to. */
307 /* Number of binding contours started in current function
308 before the label reference. */
309 int block_start_count;
310 /* The outermost stack level that should be restored for this jump.
311 Each time a binding contour that resets the stack is exited,
312 if the target label is *not* yet defined, this slot is updated. */
314 /* List of lists of cleanup expressions to be run by this goto.
315 There is one element for each block that this goto is within.
316 The tail of this list can be 0,
317 if all remaining elements would be empty.
318 The TREE_VALUE contains the cleanup list of that block as of the
319 time this goto was seen.
320 The TREE_ADDRESSABLE flag is 1 for a block that has been exited. */
321 tree cleanup_list_list;
324 /* Within any binding contour that must restore a stack level,
325 all labels are recorded with a chain of these structures. */
329 /* Points to following fixup. */
330 struct label_chain *next;
336 /* Chain of all pending binding contours. */
337 struct nesting *x_block_stack;
339 /* If any new stacks are added here, add them to POPSTACKS too. */
341 /* Chain of all pending binding contours that restore stack levels
343 struct nesting *x_stack_block_stack;
345 /* Chain of all pending conditional statements. */
346 struct nesting *x_cond_stack;
348 /* Chain of all pending loops. */
349 struct nesting *x_loop_stack;
351 /* Chain of all pending case or switch statements. */
352 struct nesting *x_case_stack;
354 /* Separate chain including all of the above,
355 chained through the `all' field. */
356 struct nesting *x_nesting_stack;
358 /* Number of entries on nesting_stack now. */
361 /* Number of binding contours started so far in this function. */
362 int x_block_start_count;
364 /* Each time we expand an expression-statement,
365 record the expr's type and its RTL value here. */
366 tree x_last_expr_type;
367 rtx x_last_expr_value;
369 /* Nonzero if within a ({...}) grouping, in which case we must
370 always compute a value for each expr-stmt in case it is the last one. */
371 int x_expr_stmts_for_value;
373 /* Filename and line number of last line-number note,
374 whether we actually emitted it or not. */
375 const char *x_emit_filename;
378 struct goto_fixup *x_goto_fixup_chain;
381 #define block_stack (cfun->stmt->x_block_stack)
382 #define stack_block_stack (cfun->stmt->x_stack_block_stack)
383 #define cond_stack (cfun->stmt->x_cond_stack)
384 #define loop_stack (cfun->stmt->x_loop_stack)
385 #define case_stack (cfun->stmt->x_case_stack)
386 #define nesting_stack (cfun->stmt->x_nesting_stack)
387 #define nesting_depth (cfun->stmt->x_nesting_depth)
388 #define current_block_start_count (cfun->stmt->x_block_start_count)
389 #define last_expr_type (cfun->stmt->x_last_expr_type)
390 #define last_expr_value (cfun->stmt->x_last_expr_value)
391 #define expr_stmts_for_value (cfun->stmt->x_expr_stmts_for_value)
392 #define emit_filename (cfun->stmt->x_emit_filename)
393 #define emit_lineno (cfun->stmt->x_emit_lineno)
394 #define goto_fixup_chain (cfun->stmt->x_goto_fixup_chain)
396 /* Non-zero if we are using EH to handle cleanus. */
397 static int using_eh_for_cleanups_p = 0;
399 static int n_occurrences PARAMS ((int, const char *));
400 static void expand_goto_internal PARAMS ((tree, rtx, rtx));
401 static int expand_fixup PARAMS ((tree, rtx, rtx));
402 static rtx expand_nl_handler_label PARAMS ((rtx, rtx));
403 static void expand_nl_goto_receiver PARAMS ((void));
404 static void expand_nl_goto_receivers PARAMS ((struct nesting *));
405 static void fixup_gotos PARAMS ((struct nesting *, rtx, tree,
407 static bool check_operand_nalternatives PARAMS ((tree, tree));
408 static bool check_unique_operand_names PARAMS ((tree, tree));
409 static tree resolve_operand_names PARAMS ((tree, tree, tree,
411 static char *resolve_operand_name_1 PARAMS ((char *, tree, tree));
412 static void expand_null_return_1 PARAMS ((rtx));
413 static void expand_value_return PARAMS ((rtx));
414 static int tail_recursion_args PARAMS ((tree, tree));
415 static void expand_cleanups PARAMS ((tree, tree, int, int));
416 static void check_seenlabel PARAMS ((void));
417 static void do_jump_if_equal PARAMS ((rtx, rtx, rtx, int));
418 static int estimate_case_costs PARAMS ((case_node_ptr));
419 static void group_case_nodes PARAMS ((case_node_ptr));
420 static void balance_case_nodes PARAMS ((case_node_ptr *,
422 static int node_has_low_bound PARAMS ((case_node_ptr, tree));
423 static int node_has_high_bound PARAMS ((case_node_ptr, tree));
424 static int node_is_bounded PARAMS ((case_node_ptr, tree));
425 static void emit_jump_if_reachable PARAMS ((rtx));
426 static void emit_case_nodes PARAMS ((rtx, case_node_ptr, rtx, tree));
427 static struct case_node *case_tree2list PARAMS ((case_node *, case_node *));
428 static void mark_cond_nesting PARAMS ((struct nesting *));
429 static void mark_loop_nesting PARAMS ((struct nesting *));
430 static void mark_block_nesting PARAMS ((struct nesting *));
431 static void mark_case_nesting PARAMS ((struct nesting *));
432 static void mark_case_node PARAMS ((struct case_node *));
433 static void mark_goto_fixup PARAMS ((struct goto_fixup *));
434 static void free_case_nodes PARAMS ((case_node_ptr));
437 using_eh_for_cleanups ()
439 using_eh_for_cleanups_p = 1;
442 /* Mark N (known to be a cond-nesting) for GC. */
445 mark_cond_nesting (n)
450 ggc_mark_rtx (n->exit_label);
451 ggc_mark_rtx (n->data.cond.endif_label);
452 ggc_mark_rtx (n->data.cond.next_label);
458 /* Mark N (known to be a loop-nesting) for GC. */
461 mark_loop_nesting (n)
467 ggc_mark_rtx (n->exit_label);
468 ggc_mark_rtx (n->data.loop.start_label);
469 ggc_mark_rtx (n->data.loop.end_label);
470 ggc_mark_rtx (n->data.loop.alt_end_label);
471 ggc_mark_rtx (n->data.loop.continue_label);
477 /* Mark N (known to be a block-nesting) for GC. */
480 mark_block_nesting (n)
485 struct label_chain *l;
487 ggc_mark_rtx (n->exit_label);
488 ggc_mark_rtx (n->data.block.stack_level);
489 ggc_mark_rtx (n->data.block.first_insn);
490 ggc_mark_tree (n->data.block.cleanups);
491 ggc_mark_tree (n->data.block.outer_cleanups);
493 for (l = n->data.block.label_chain; l != NULL; l = l->next)
496 ggc_mark_tree (l->label);
499 ggc_mark_rtx (n->data.block.last_unconditional_cleanup);
501 /* ??? cleanup_ptr never points outside the stack, does it? */
507 /* Mark N (known to be a case-nesting) for GC. */
510 mark_case_nesting (n)
515 ggc_mark_rtx (n->exit_label);
516 ggc_mark_rtx (n->data.case_stmt.start);
518 ggc_mark_tree (n->data.case_stmt.default_label);
519 ggc_mark_tree (n->data.case_stmt.index_expr);
520 ggc_mark_tree (n->data.case_stmt.nominal_type);
522 mark_case_node (n->data.case_stmt.case_list);
535 ggc_mark_tree (c->low);
536 ggc_mark_tree (c->high);
537 ggc_mark_tree (c->code_label);
539 mark_case_node (c->right);
540 mark_case_node (c->left);
548 struct goto_fixup *g;
553 ggc_mark_rtx (g->before_jump);
554 ggc_mark_tree (g->target);
555 ggc_mark_tree (g->context);
556 ggc_mark_rtx (g->target_rtl);
557 ggc_mark_rtx (g->stack_level);
558 ggc_mark_tree (g->cleanup_list_list);
564 /* Clear out all parts of the state in F that can safely be discarded
565 after the function has been compiled, to let garbage collection
566 reclaim the memory. */
572 /* We're about to free the function obstack. If we hold pointers to
573 things allocated there, then we'll try to mark them when we do
574 GC. So, we clear them out here explicitly. */
584 struct stmt_status *p;
589 mark_block_nesting (p->x_block_stack);
590 mark_cond_nesting (p->x_cond_stack);
591 mark_loop_nesting (p->x_loop_stack);
592 mark_case_nesting (p->x_case_stack);
594 ggc_mark_tree (p->x_last_expr_type);
595 /* last_epxr_value is only valid if last_expr_type is nonzero. */
596 if (p->x_last_expr_type)
597 ggc_mark_rtx (p->x_last_expr_value);
599 mark_goto_fixup (p->x_goto_fixup_chain);
605 gcc_obstack_init (&stmt_obstack);
609 init_stmt_for_function ()
611 cfun->stmt = (struct stmt_status *) xmalloc (sizeof (struct stmt_status));
613 /* We are not currently within any block, conditional, loop or case. */
615 stack_block_stack = 0;
622 current_block_start_count = 0;
624 /* No gotos have been expanded yet. */
625 goto_fixup_chain = 0;
627 /* We are not processing a ({...}) grouping. */
628 expr_stmts_for_value = 0;
630 last_expr_value = NULL_RTX;
633 /* Return nonzero if anything is pushed on the loop, condition, or case
638 return cond_stack || loop_stack || case_stack;
641 /* Record the current file and line. Called from emit_line_note. */
643 set_file_and_line_for_stmt (file, line)
647 /* If we're outputting an inline function, and we add a line note,
648 there may be no CFUN->STMT information. So, there's no need to
652 emit_filename = file;
657 /* Emit a no-op instruction. */
664 last_insn = get_last_insn ();
666 && (GET_CODE (last_insn) == CODE_LABEL
667 || (GET_CODE (last_insn) == NOTE
668 && prev_real_insn (last_insn) == 0)))
669 emit_insn (gen_nop ());
672 /* Return the rtx-label that corresponds to a LABEL_DECL,
673 creating it if necessary. */
679 if (TREE_CODE (label) != LABEL_DECL)
682 if (!DECL_RTL_SET_P (label))
683 SET_DECL_RTL (label, gen_label_rtx ());
685 return DECL_RTL (label);
689 /* Add an unconditional jump to LABEL as the next sequential instruction. */
695 do_pending_stack_adjust ();
696 emit_jump_insn (gen_jump (label));
700 /* Emit code to jump to the address
701 specified by the pointer expression EXP. */
704 expand_computed_goto (exp)
707 rtx x = expand_expr (exp, NULL_RTX, VOIDmode, 0);
709 #ifdef POINTERS_EXTEND_UNSIGNED
710 x = convert_memory_address (Pmode, x);
714 /* Be sure the function is executable. */
715 if (current_function_check_memory_usage)
716 emit_library_call (chkr_check_exec_libfunc, LCT_CONST_MAKE_BLOCK,
717 VOIDmode, 1, x, ptr_mode);
719 do_pending_stack_adjust ();
720 emit_indirect_jump (x);
722 current_function_has_computed_jump = 1;
725 /* Handle goto statements and the labels that they can go to. */
727 /* Specify the location in the RTL code of a label LABEL,
728 which is a LABEL_DECL tree node.
730 This is used for the kind of label that the user can jump to with a
731 goto statement, and for alternatives of a switch or case statement.
732 RTL labels generated for loops and conditionals don't go through here;
733 they are generated directly at the RTL level, by other functions below.
735 Note that this has nothing to do with defining label *names*.
736 Languages vary in how they do that and what that even means. */
742 struct label_chain *p;
744 do_pending_stack_adjust ();
745 emit_label (label_rtx (label));
746 if (DECL_NAME (label))
747 LABEL_NAME (DECL_RTL (label)) = IDENTIFIER_POINTER (DECL_NAME (label));
749 if (stack_block_stack != 0)
751 p = (struct label_chain *) ggc_alloc (sizeof (struct label_chain));
752 p->next = stack_block_stack->data.block.label_chain;
753 stack_block_stack->data.block.label_chain = p;
758 /* Declare that LABEL (a LABEL_DECL) may be used for nonlocal gotos
759 from nested functions. */
762 declare_nonlocal_label (label)
765 rtx slot = assign_stack_local (Pmode, GET_MODE_SIZE (Pmode), 0);
767 nonlocal_labels = tree_cons (NULL_TREE, label, nonlocal_labels);
768 LABEL_PRESERVE_P (label_rtx (label)) = 1;
769 if (nonlocal_goto_handler_slots == 0)
771 emit_stack_save (SAVE_NONLOCAL,
772 &nonlocal_goto_stack_level,
773 PREV_INSN (tail_recursion_reentry));
775 nonlocal_goto_handler_slots
776 = gen_rtx_EXPR_LIST (VOIDmode, slot, nonlocal_goto_handler_slots);
779 /* Generate RTL code for a `goto' statement with target label LABEL.
780 LABEL should be a LABEL_DECL tree node that was or will later be
781 defined with `expand_label'. */
789 /* Check for a nonlocal goto to a containing function. */
790 context = decl_function_context (label);
791 if (context != 0 && context != current_function_decl)
793 struct function *p = find_function_data (context);
794 rtx label_ref = gen_rtx_LABEL_REF (Pmode, label_rtx (label));
795 rtx handler_slot, static_chain, save_area, insn;
798 /* Find the corresponding handler slot for this label. */
799 handler_slot = p->x_nonlocal_goto_handler_slots;
800 for (link = p->x_nonlocal_labels; TREE_VALUE (link) != label;
801 link = TREE_CHAIN (link))
802 handler_slot = XEXP (handler_slot, 1);
803 handler_slot = XEXP (handler_slot, 0);
805 p->has_nonlocal_label = 1;
806 current_function_has_nonlocal_goto = 1;
807 LABEL_REF_NONLOCAL_P (label_ref) = 1;
809 /* Copy the rtl for the slots so that they won't be shared in
810 case the virtual stack vars register gets instantiated differently
811 in the parent than in the child. */
813 static_chain = copy_to_reg (lookup_static_chain (label));
815 /* Get addr of containing function's current nonlocal goto handler,
816 which will do any cleanups and then jump to the label. */
817 handler_slot = copy_to_reg (replace_rtx (copy_rtx (handler_slot),
818 virtual_stack_vars_rtx,
821 /* Get addr of containing function's nonlocal save area. */
822 save_area = p->x_nonlocal_goto_stack_level;
824 save_area = replace_rtx (copy_rtx (save_area),
825 virtual_stack_vars_rtx, static_chain);
827 #if HAVE_nonlocal_goto
828 if (HAVE_nonlocal_goto)
829 emit_insn (gen_nonlocal_goto (static_chain, handler_slot,
830 save_area, label_ref));
834 /* Restore frame pointer for containing function.
835 This sets the actual hard register used for the frame pointer
836 to the location of the function's incoming static chain info.
837 The non-local goto handler will then adjust it to contain the
838 proper value and reload the argument pointer, if needed. */
839 emit_move_insn (hard_frame_pointer_rtx, static_chain);
840 emit_stack_restore (SAVE_NONLOCAL, save_area, NULL_RTX);
842 /* USE of hard_frame_pointer_rtx added for consistency;
843 not clear if really needed. */
844 emit_insn (gen_rtx_USE (VOIDmode, hard_frame_pointer_rtx));
845 emit_insn (gen_rtx_USE (VOIDmode, stack_pointer_rtx));
846 emit_indirect_jump (handler_slot);
849 /* Search backwards to the jump insn and mark it as a
851 for (insn = get_last_insn (); insn; insn = PREV_INSN (insn))
853 if (GET_CODE (insn) == JUMP_INSN)
855 REG_NOTES (insn) = alloc_EXPR_LIST (REG_NON_LOCAL_GOTO,
856 const0_rtx, REG_NOTES (insn));
859 else if (GET_CODE (insn) == CALL_INSN)
864 expand_goto_internal (label, label_rtx (label), NULL_RTX);
867 /* Generate RTL code for a `goto' statement with target label BODY.
868 LABEL should be a LABEL_REF.
869 LAST_INSN, if non-0, is the rtx we should consider as the last
870 insn emitted (for the purposes of cleaning up a return). */
873 expand_goto_internal (body, label, last_insn)
878 struct nesting *block;
881 if (GET_CODE (label) != CODE_LABEL)
884 /* If label has already been defined, we can tell now
885 whether and how we must alter the stack level. */
887 if (PREV_INSN (label) != 0)
889 /* Find the innermost pending block that contains the label.
890 (Check containment by comparing insn-uids.)
891 Then restore the outermost stack level within that block,
892 and do cleanups of all blocks contained in it. */
893 for (block = block_stack; block; block = block->next)
895 if (INSN_UID (block->data.block.first_insn) < INSN_UID (label))
897 if (block->data.block.stack_level != 0)
898 stack_level = block->data.block.stack_level;
899 /* Execute the cleanups for blocks we are exiting. */
900 if (block->data.block.cleanups != 0)
902 expand_cleanups (block->data.block.cleanups, NULL_TREE, 1, 1);
903 do_pending_stack_adjust ();
909 /* Ensure stack adjust isn't done by emit_jump, as this
910 would clobber the stack pointer. This one should be
911 deleted as dead by flow. */
912 clear_pending_stack_adjust ();
913 do_pending_stack_adjust ();
915 /* Don't do this adjust if it's to the end label and this function
916 is to return with a depressed stack pointer. */
917 if (label == return_label
918 && (((TREE_CODE (TREE_TYPE (current_function_decl))
920 && (TYPE_RETURNS_STACK_DEPRESSED
921 (TREE_TYPE (current_function_decl))))))
924 emit_stack_restore (SAVE_BLOCK, stack_level, NULL_RTX);
927 if (body != 0 && DECL_TOO_LATE (body))
928 error ("jump to `%s' invalidly jumps into binding contour",
929 IDENTIFIER_POINTER (DECL_NAME (body)));
931 /* Label not yet defined: may need to put this goto
932 on the fixup list. */
933 else if (! expand_fixup (body, label, last_insn))
935 /* No fixup needed. Record that the label is the target
936 of at least one goto that has no fixup. */
938 TREE_ADDRESSABLE (body) = 1;
944 /* Generate if necessary a fixup for a goto
945 whose target label in tree structure (if any) is TREE_LABEL
946 and whose target in rtl is RTL_LABEL.
948 If LAST_INSN is nonzero, we pretend that the jump appears
949 after insn LAST_INSN instead of at the current point in the insn stream.
951 The fixup will be used later to insert insns just before the goto.
952 Those insns will restore the stack level as appropriate for the
953 target label, and will (in the case of C++) also invoke any object
954 destructors which have to be invoked when we exit the scopes which
955 are exited by the goto.
957 Value is nonzero if a fixup is made. */
960 expand_fixup (tree_label, rtl_label, last_insn)
965 struct nesting *block, *end_block;
967 /* See if we can recognize which block the label will be output in.
968 This is possible in some very common cases.
969 If we succeed, set END_BLOCK to that block.
970 Otherwise, set it to 0. */
973 && (rtl_label == cond_stack->data.cond.endif_label
974 || rtl_label == cond_stack->data.cond.next_label))
975 end_block = cond_stack;
976 /* If we are in a loop, recognize certain labels which
977 are likely targets. This reduces the number of fixups
978 we need to create. */
980 && (rtl_label == loop_stack->data.loop.start_label
981 || rtl_label == loop_stack->data.loop.end_label
982 || rtl_label == loop_stack->data.loop.continue_label))
983 end_block = loop_stack;
987 /* Now set END_BLOCK to the binding level to which we will return. */
991 struct nesting *next_block = end_block->all;
994 /* First see if the END_BLOCK is inside the innermost binding level.
995 If so, then no cleanups or stack levels are relevant. */
996 while (next_block && next_block != block)
997 next_block = next_block->all;
1002 /* Otherwise, set END_BLOCK to the innermost binding level
1003 which is outside the relevant control-structure nesting. */
1004 next_block = block_stack->next;
1005 for (block = block_stack; block != end_block; block = block->all)
1006 if (block == next_block)
1007 next_block = next_block->next;
1008 end_block = next_block;
1011 /* Does any containing block have a stack level or cleanups?
1012 If not, no fixup is needed, and that is the normal case
1013 (the only case, for standard C). */
1014 for (block = block_stack; block != end_block; block = block->next)
1015 if (block->data.block.stack_level != 0
1016 || block->data.block.cleanups != 0)
1019 if (block != end_block)
1021 /* Ok, a fixup is needed. Add a fixup to the list of such. */
1022 struct goto_fixup *fixup
1023 = (struct goto_fixup *) ggc_alloc (sizeof (struct goto_fixup));
1024 /* In case an old stack level is restored, make sure that comes
1025 after any pending stack adjust. */
1026 /* ?? If the fixup isn't to come at the present position,
1027 doing the stack adjust here isn't useful. Doing it with our
1028 settings at that location isn't useful either. Let's hope
1031 do_pending_stack_adjust ();
1032 fixup->target = tree_label;
1033 fixup->target_rtl = rtl_label;
1035 /* Create a BLOCK node and a corresponding matched set of
1036 NOTE_INSN_BLOCK_BEG and NOTE_INSN_BLOCK_END notes at
1037 this point. The notes will encapsulate any and all fixup
1038 code which we might later insert at this point in the insn
1039 stream. Also, the BLOCK node will be the parent (i.e. the
1040 `SUPERBLOCK') of any other BLOCK nodes which we might create
1041 later on when we are expanding the fixup code.
1043 Note that optimization passes (including expand_end_loop)
1044 might move the *_BLOCK notes away, so we use a NOTE_INSN_DELETED
1045 as a placeholder. */
1048 rtx original_before_jump
1049 = last_insn ? last_insn : get_last_insn ();
1054 block = make_node (BLOCK);
1055 TREE_USED (block) = 1;
1057 if (!cfun->x_whole_function_mode_p)
1058 insert_block (block);
1062 = BLOCK_CHAIN (DECL_INITIAL (current_function_decl));
1063 BLOCK_CHAIN (DECL_INITIAL (current_function_decl))
1068 start = emit_note (NULL, NOTE_INSN_BLOCK_BEG);
1069 if (cfun->x_whole_function_mode_p)
1070 NOTE_BLOCK (start) = block;
1071 fixup->before_jump = emit_note (NULL, NOTE_INSN_DELETED);
1072 end = emit_note (NULL, NOTE_INSN_BLOCK_END);
1073 if (cfun->x_whole_function_mode_p)
1074 NOTE_BLOCK (end) = block;
1075 fixup->context = block;
1077 emit_insns_after (start, original_before_jump);
1080 fixup->block_start_count = current_block_start_count;
1081 fixup->stack_level = 0;
1082 fixup->cleanup_list_list
1083 = ((block->data.block.outer_cleanups
1084 || block->data.block.cleanups)
1085 ? tree_cons (NULL_TREE, block->data.block.cleanups,
1086 block->data.block.outer_cleanups)
1088 fixup->next = goto_fixup_chain;
1089 goto_fixup_chain = fixup;
1095 /* Expand any needed fixups in the outputmost binding level of the
1096 function. FIRST_INSN is the first insn in the function. */
1099 expand_fixups (first_insn)
1102 fixup_gotos (NULL, NULL_RTX, NULL_TREE, first_insn, 0);
1105 /* When exiting a binding contour, process all pending gotos requiring fixups.
1106 THISBLOCK is the structure that describes the block being exited.
1107 STACK_LEVEL is the rtx for the stack level to restore exiting this contour.
1108 CLEANUP_LIST is a list of expressions to evaluate on exiting this contour.
1109 FIRST_INSN is the insn that began this contour.
1111 Gotos that jump out of this contour must restore the
1112 stack level and do the cleanups before actually jumping.
1114 DONT_JUMP_IN nonzero means report error there is a jump into this
1115 contour from before the beginning of the contour.
1116 This is also done if STACK_LEVEL is nonzero. */
1119 fixup_gotos (thisblock, stack_level, cleanup_list, first_insn, dont_jump_in)
1120 struct nesting *thisblock;
1126 struct goto_fixup *f, *prev;
1128 /* F is the fixup we are considering; PREV is the previous one. */
1129 /* We run this loop in two passes so that cleanups of exited blocks
1130 are run first, and blocks that are exited are marked so
1133 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
1135 /* Test for a fixup that is inactive because it is already handled. */
1136 if (f->before_jump == 0)
1138 /* Delete inactive fixup from the chain, if that is easy to do. */
1140 prev->next = f->next;
1142 /* Has this fixup's target label been defined?
1143 If so, we can finalize it. */
1144 else if (PREV_INSN (f->target_rtl) != 0)
1148 /* If this fixup jumped into this contour from before the beginning
1149 of this contour, report an error. This code used to use
1150 the first non-label insn after f->target_rtl, but that's
1151 wrong since such can be added, by things like put_var_into_stack
1152 and have INSN_UIDs that are out of the range of the block. */
1153 /* ??? Bug: this does not detect jumping in through intermediate
1154 blocks that have stack levels or cleanups.
1155 It detects only a problem with the innermost block
1156 around the label. */
1158 && (dont_jump_in || stack_level || cleanup_list)
1159 && INSN_UID (first_insn) < INSN_UID (f->target_rtl)
1160 && INSN_UID (first_insn) > INSN_UID (f->before_jump)
1161 && ! DECL_ERROR_ISSUED (f->target))
1163 error_with_decl (f->target,
1164 "label `%s' used before containing binding contour");
1165 /* Prevent multiple errors for one label. */
1166 DECL_ERROR_ISSUED (f->target) = 1;
1169 /* We will expand the cleanups into a sequence of their own and
1170 then later on we will attach this new sequence to the insn
1171 stream just ahead of the actual jump insn. */
1175 /* Temporarily restore the lexical context where we will
1176 logically be inserting the fixup code. We do this for the
1177 sake of getting the debugging information right. */
1180 set_block (f->context);
1182 /* Expand the cleanups for blocks this jump exits. */
1183 if (f->cleanup_list_list)
1186 for (lists = f->cleanup_list_list; lists; lists = TREE_CHAIN (lists))
1187 /* Marked elements correspond to blocks that have been closed.
1188 Do their cleanups. */
1189 if (TREE_ADDRESSABLE (lists)
1190 && TREE_VALUE (lists) != 0)
1192 expand_cleanups (TREE_VALUE (lists), NULL_TREE, 1, 1);
1193 /* Pop any pushes done in the cleanups,
1194 in case function is about to return. */
1195 do_pending_stack_adjust ();
1199 /* Restore stack level for the biggest contour that this
1200 jump jumps out of. */
1202 && ! (f->target_rtl == return_label
1203 && ((TREE_CODE (TREE_TYPE (current_function_decl))
1205 && (TYPE_RETURNS_STACK_DEPRESSED
1206 (TREE_TYPE (current_function_decl))))))
1207 emit_stack_restore (SAVE_BLOCK, f->stack_level, f->before_jump);
1209 /* Finish up the sequence containing the insns which implement the
1210 necessary cleanups, and then attach that whole sequence to the
1211 insn stream just ahead of the actual jump insn. Attaching it
1212 at that point insures that any cleanups which are in fact
1213 implicit C++ object destructions (which must be executed upon
1214 leaving the block) appear (to the debugger) to be taking place
1215 in an area of the generated code where the object(s) being
1216 destructed are still "in scope". */
1218 cleanup_insns = get_insns ();
1222 emit_insns_after (cleanup_insns, f->before_jump);
1228 /* For any still-undefined labels, do the cleanups for this block now.
1229 We must do this now since items in the cleanup list may go out
1230 of scope when the block ends. */
1231 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
1232 if (f->before_jump != 0
1233 && PREV_INSN (f->target_rtl) == 0
1234 /* Label has still not appeared. If we are exiting a block with
1235 a stack level to restore, that started before the fixup,
1236 mark this stack level as needing restoration
1237 when the fixup is later finalized. */
1239 /* Note: if THISBLOCK == 0 and we have a label that hasn't appeared, it
1240 means the label is undefined. That's erroneous, but possible. */
1241 && (thisblock->data.block.block_start_count
1242 <= f->block_start_count))
1244 tree lists = f->cleanup_list_list;
1247 for (; lists; lists = TREE_CHAIN (lists))
1248 /* If the following elt. corresponds to our containing block
1249 then the elt. must be for this block. */
1250 if (TREE_CHAIN (lists) == thisblock->data.block.outer_cleanups)
1254 set_block (f->context);
1255 expand_cleanups (TREE_VALUE (lists), NULL_TREE, 1, 1);
1256 do_pending_stack_adjust ();
1257 cleanup_insns = get_insns ();
1260 if (cleanup_insns != 0)
1262 = emit_insns_after (cleanup_insns, f->before_jump);
1264 f->cleanup_list_list = TREE_CHAIN (lists);
1268 f->stack_level = stack_level;
1272 /* Return the number of times character C occurs in string S. */
1274 n_occurrences (c, s)
1284 /* Generate RTL for an asm statement (explicit assembler code).
1285 BODY is a STRING_CST node containing the assembler code text,
1286 or an ADDR_EXPR containing a STRING_CST. */
1292 if (current_function_check_memory_usage)
1294 error ("`asm' cannot be used in function where memory usage is checked");
1298 if (TREE_CODE (body) == ADDR_EXPR)
1299 body = TREE_OPERAND (body, 0);
1301 emit_insn (gen_rtx_ASM_INPUT (VOIDmode,
1302 TREE_STRING_POINTER (body)));
1306 /* Parse the output constraint pointed to by *CONSTRAINT_P. It is the
1307 OPERAND_NUMth output operand, indexed from zero. There are NINPUTS
1308 inputs and NOUTPUTS outputs to this extended-asm. Upon return,
1309 *ALLOWS_MEM will be TRUE iff the constraint allows the use of a
1310 memory operand. Similarly, *ALLOWS_REG will be TRUE iff the
1311 constraint allows the use of a register operand. And, *IS_INOUT
1312 will be true if the operand is read-write, i.e., if it is used as
1313 an input as well as an output. If *CONSTRAINT_P is not in
1314 canonical form, it will be made canonical. (Note that `+' will be
1315 rpelaced with `=' as part of this process.)
1317 Returns TRUE if all went well; FALSE if an error occurred. */
1320 parse_output_constraint (constraint_p,
1327 const char **constraint_p;
1335 const char *constraint = *constraint_p;
1338 /* Assume the constraint doesn't allow the use of either a register
1340 *allows_mem = false;
1341 *allows_reg = false;
1343 /* Allow the `=' or `+' to not be at the beginning of the string,
1344 since it wasn't explicitly documented that way, and there is a
1345 large body of code that puts it last. Swap the character to
1346 the front, so as not to uglify any place else. */
1347 p = strchr (constraint, '=');
1349 p = strchr (constraint, '+');
1351 /* If the string doesn't contain an `=', issue an error
1355 error ("output operand constraint lacks `='");
1359 /* If the constraint begins with `+', then the operand is both read
1360 from and written to. */
1361 *is_inout = (*p == '+');
1363 /* Canonicalize the output constraint so that it begins with `='. */
1364 if (p != constraint || is_inout)
1367 size_t c_len = strlen (constraint);
1369 if (p != constraint)
1370 warning ("output constraint `%c' for operand %d is not at the beginning",
1373 /* Make a copy of the constraint. */
1374 buf = alloca (c_len + 1);
1375 strcpy (buf, constraint);
1376 /* Swap the first character and the `=' or `+'. */
1377 buf[p - constraint] = buf[0];
1378 /* Make sure the first character is an `='. (Until we do this,
1379 it might be a `+'.) */
1381 /* Replace the constraint with the canonicalized string. */
1382 *constraint_p = ggc_alloc_string (buf, c_len);
1383 constraint = *constraint_p;
1386 /* Loop through the constraint string. */
1387 for (p = constraint + 1; *p; ++p)
1392 error ("operand constraint contains '+' or '=' at illegal position.");
1396 if (operand_num + 1 == ninputs + noutputs)
1398 error ("`%%' constraint used with last operand");
1403 case 'V': case 'm': case 'o':
1407 case '?': case '!': case '*': case '&': case '#':
1408 case 'E': case 'F': case 'G': case 'H':
1409 case 's': case 'i': case 'n':
1410 case 'I': case 'J': case 'K': case 'L': case 'M':
1411 case 'N': case 'O': case 'P': case ',':
1414 case '0': case '1': case '2': case '3': case '4':
1415 case '5': case '6': case '7': case '8': case '9':
1417 error ("matching constraint not valid in output operand");
1421 /* ??? Before flow, auto inc/dec insns are not supposed to exist,
1422 excepting those that expand_call created. So match memory
1439 if (REG_CLASS_FROM_LETTER (*p) != NO_REGS)
1441 #ifdef EXTRA_CONSTRAINT
1444 /* Otherwise we can't assume anything about the nature of
1445 the constraint except that it isn't purely registers.
1446 Treat it like "g" and hope for the best. */
1457 /* Generate RTL for an asm statement with arguments.
1458 STRING is the instruction template.
1459 OUTPUTS is a list of output arguments (lvalues); INPUTS a list of inputs.
1460 Each output or input has an expression in the TREE_VALUE and
1461 a constraint-string in the TREE_PURPOSE.
1462 CLOBBERS is a list of STRING_CST nodes each naming a hard register
1463 that is clobbered by this insn.
1465 Not all kinds of lvalue that may appear in OUTPUTS can be stored directly.
1466 Some elements of OUTPUTS may be replaced with trees representing temporary
1467 values. The caller should copy those temporary values to the originally
1470 VOL nonzero means the insn is volatile; don't optimize it. */
1473 expand_asm_operands (string, outputs, inputs, clobbers, vol, filename, line)
1474 tree string, outputs, inputs, clobbers;
1476 const char *filename;
1479 rtvec argvec, constraintvec;
1481 int ninputs = list_length (inputs);
1482 int noutputs = list_length (outputs);
1487 /* Vector of RTX's of evaluated output operands. */
1488 rtx *output_rtx = (rtx *) alloca (noutputs * sizeof (rtx));
1489 int *inout_opnum = (int *) alloca (noutputs * sizeof (int));
1490 rtx *real_output_rtx = (rtx *) alloca (noutputs * sizeof (rtx));
1491 enum machine_mode *inout_mode
1492 = (enum machine_mode *) alloca (noutputs * sizeof (enum machine_mode));
1493 const char **constraints
1494 = (const char **) alloca ((noutputs + ninputs) * sizeof (const char *));
1495 /* The insn we have emitted. */
1497 int old_generating_concat_p = generating_concat_p;
1499 /* An ASM with no outputs needs to be treated as volatile, for now. */
1503 if (current_function_check_memory_usage)
1505 error ("`asm' cannot be used in function where memory usage is checked");
1509 if (! check_operand_nalternatives (outputs, inputs))
1512 if (! check_unique_operand_names (outputs, inputs))
1515 string = resolve_operand_names (string, outputs, inputs, constraints);
1517 #ifdef MD_ASM_CLOBBERS
1518 /* Sometimes we wish to automatically clobber registers across an asm.
1519 Case in point is when the i386 backend moved from cc0 to a hard reg --
1520 maintaining source-level compatability means automatically clobbering
1521 the flags register. */
1522 MD_ASM_CLOBBERS (clobbers);
1525 /* Count the number of meaningful clobbered registers, ignoring what
1526 we would ignore later. */
1528 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1530 const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1532 i = decode_reg_name (regname);
1533 if (i >= 0 || i == -4)
1536 error ("unknown register name `%s' in `asm'", regname);
1541 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1543 tree val = TREE_VALUE (tail);
1544 tree type = TREE_TYPE (val);
1549 /* If there's an erroneous arg, emit no insn. */
1550 if (type == error_mark_node)
1553 /* Make sure constraint has `=' and does not have `+'. Also, see
1554 if it allows any register. Be liberal on the latter test, since
1555 the worst that happens if we get it wrong is we issue an error
1558 /* Try to parse the output constraint. If that fails, there's
1559 no point in going further. */
1560 if (!parse_output_constraint (&constraints[i],
1569 /* If an output operand is not a decl or indirect ref and our constraint
1570 allows a register, make a temporary to act as an intermediate.
1571 Make the asm insn write into that, then our caller will copy it to
1572 the real output operand. Likewise for promoted variables. */
1574 generating_concat_p = 0;
1576 real_output_rtx[i] = NULL_RTX;
1577 if ((TREE_CODE (val) == INDIRECT_REF
1580 && (allows_mem || GET_CODE (DECL_RTL (val)) == REG)
1581 && ! (GET_CODE (DECL_RTL (val)) == REG
1582 && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type)))
1587 mark_addressable (TREE_VALUE (tail));
1590 = expand_expr (TREE_VALUE (tail), NULL_RTX, VOIDmode,
1591 EXPAND_MEMORY_USE_WO);
1593 if (! allows_reg && GET_CODE (output_rtx[i]) != MEM)
1594 error ("output number %d not directly addressable", i);
1595 if ((! allows_mem && GET_CODE (output_rtx[i]) == MEM)
1596 || GET_CODE (output_rtx[i]) == CONCAT)
1598 real_output_rtx[i] = protect_from_queue (output_rtx[i], 1);
1599 output_rtx[i] = gen_reg_rtx (GET_MODE (output_rtx[i]));
1601 emit_move_insn (output_rtx[i], real_output_rtx[i]);
1606 output_rtx[i] = assign_temp (type, 0, 0, 1);
1607 TREE_VALUE (tail) = make_tree (type, output_rtx[i]);
1610 generating_concat_p = old_generating_concat_p;
1614 inout_mode[ninout] = TYPE_MODE (TREE_TYPE (TREE_VALUE (tail)));
1615 inout_opnum[ninout++] = i;
1620 if (ninputs + noutputs > MAX_RECOG_OPERANDS)
1622 error ("more than %d operands in `asm'", MAX_RECOG_OPERANDS);
1626 /* Make vectors for the expression-rtx, constraint strings,
1627 and named operands. */
1629 argvec = rtvec_alloc (ninputs);
1630 constraintvec = rtvec_alloc (ninputs);
1632 body = gen_rtx_ASM_OPERANDS ((noutputs == 0 ? VOIDmode
1633 : GET_MODE (output_rtx[0])),
1634 TREE_STRING_POINTER (string),
1635 empty_string, 0, argvec, constraintvec,
1638 MEM_VOLATILE_P (body) = vol;
1640 /* Eval the inputs and put them into ARGVEC.
1641 Put their constraints into ASM_INPUTs and store in CONSTRAINTS. */
1643 for (i = 0, tail = inputs; tail; tail = TREE_CHAIN (tail), ++i)
1646 int allows_reg = 0, allows_mem = 0;
1647 const char *constraint, *orig_constraint;
1651 /* If there's an erroneous arg, emit no insn,
1652 because the ASM_INPUT would get VOIDmode
1653 and that could cause a crash in reload. */
1654 if (TREE_TYPE (TREE_VALUE (tail)) == error_mark_node)
1657 /* ??? Can this happen, and does the error message make any sense? */
1658 if (TREE_PURPOSE (tail) == NULL_TREE)
1660 error ("hard register `%s' listed as input operand to `asm'",
1661 TREE_STRING_POINTER (TREE_VALUE (tail)) );
1665 orig_constraint = constraint = constraints[i + noutputs];
1666 c_len = strlen (constraint);
1668 /* Make sure constraint has neither `=', `+', nor '&'. */
1670 for (j = 0; j < c_len; j++)
1671 switch (constraint[j])
1673 case '+': case '=': case '&':
1674 if (constraint == orig_constraint)
1676 error ("input operand constraint contains `%c'",
1683 if (constraint == orig_constraint
1684 && i + 1 == ninputs - ninout)
1686 error ("`%%' constraint used with last operand");
1691 case 'V': case 'm': case 'o':
1696 case '?': case '!': case '*': case '#':
1697 case 'E': case 'F': case 'G': case 'H':
1698 case 's': case 'i': case 'n':
1699 case 'I': case 'J': case 'K': case 'L': case 'M':
1700 case 'N': case 'O': case 'P': case ',':
1703 /* Whether or not a numeric constraint allows a register is
1704 decided by the matching constraint, and so there is no need
1705 to do anything special with them. We must handle them in
1706 the default case, so that we don't unnecessarily force
1707 operands to memory. */
1708 case '0': case '1': case '2': case '3': case '4':
1709 case '5': case '6': case '7': case '8': case '9':
1712 unsigned long match;
1714 match = strtoul (constraint + j, &end, 10);
1715 if (match >= (unsigned long) noutputs)
1717 error ("matching constraint references invalid operand number");
1721 /* Try and find the real constraint for this dup. Only do
1722 this if the matching constraint is the only alternative. */
1724 && (j == 0 || (j == 1 && constraint[0] == '%')))
1726 constraint = constraints[match];
1727 c_len = strlen (constraint);
1732 j = end - constraint;
1746 if (! ISALPHA (constraint[j]))
1748 error ("invalid punctuation `%c' in constraint",
1752 if (REG_CLASS_FROM_LETTER (constraint[j]) != NO_REGS)
1754 #ifdef EXTRA_CONSTRAINT
1757 /* Otherwise we can't assume anything about the nature of
1758 the constraint except that it isn't purely registers.
1759 Treat it like "g" and hope for the best. */
1767 if (! allows_reg && allows_mem)
1768 mark_addressable (TREE_VALUE (tail));
1770 op = expand_expr (TREE_VALUE (tail), NULL_RTX, VOIDmode, 0);
1772 /* Never pass a CONCAT to an ASM. */
1773 generating_concat_p = 0;
1774 if (GET_CODE (op) == CONCAT)
1775 op = force_reg (GET_MODE (op), op);
1777 if (asm_operand_ok (op, constraint) <= 0)
1780 op = force_reg (TYPE_MODE (TREE_TYPE (TREE_VALUE (tail))), op);
1781 else if (!allows_mem)
1782 warning ("asm operand %d probably doesn't match constraints",
1784 else if (CONSTANT_P (op))
1785 op = force_const_mem (TYPE_MODE (TREE_TYPE (TREE_VALUE (tail))),
1787 else if (GET_CODE (op) == REG
1788 || GET_CODE (op) == SUBREG
1789 || GET_CODE (op) == ADDRESSOF
1790 || GET_CODE (op) == CONCAT)
1792 tree type = TREE_TYPE (TREE_VALUE (tail));
1793 tree qual_type = build_qualified_type (type,
1795 | TYPE_QUAL_CONST));
1796 rtx memloc = assign_temp (qual_type, 1, 1, 1);
1798 emit_move_insn (memloc, op);
1802 else if (GET_CODE (op) == MEM && MEM_VOLATILE_P (op))
1803 /* We won't recognize volatile memory as available a
1804 memory_operand at this point. Ignore it. */
1806 else if (queued_subexp_p (op))
1809 /* ??? Leave this only until we have experience with what
1810 happens in combine and elsewhere when constraints are
1812 warning ("asm operand %d probably doesn't match constraints",
1815 generating_concat_p = old_generating_concat_p;
1816 ASM_OPERANDS_INPUT (body, i) = op;
1818 ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, i)
1819 = gen_rtx_ASM_INPUT (TYPE_MODE (TREE_TYPE (TREE_VALUE (tail))),
1823 /* Protect all the operands from the queue now that they have all been
1826 generating_concat_p = 0;
1828 for (i = 0; i < ninputs - ninout; i++)
1829 ASM_OPERANDS_INPUT (body, i)
1830 = protect_from_queue (ASM_OPERANDS_INPUT (body, i), 0);
1832 for (i = 0; i < noutputs; i++)
1833 output_rtx[i] = protect_from_queue (output_rtx[i], 1);
1835 /* For in-out operands, copy output rtx to input rtx. */
1836 for (i = 0; i < ninout; i++)
1838 int j = inout_opnum[i];
1841 ASM_OPERANDS_INPUT (body, ninputs - ninout + i)
1844 sprintf (buffer, "%d", j);
1845 ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, ninputs - ninout + i)
1846 = gen_rtx_ASM_INPUT (inout_mode[i], ggc_alloc_string (buffer, -1));
1849 generating_concat_p = old_generating_concat_p;
1851 /* Now, for each output, construct an rtx
1852 (set OUTPUT (asm_operands INSN OUTPUTCONSTRAINT OUTPUTNUMBER
1853 ARGVEC CONSTRAINTS OPNAMES))
1854 If there is more than one, put them inside a PARALLEL. */
1856 if (noutputs == 1 && nclobbers == 0)
1858 ASM_OPERANDS_OUTPUT_CONSTRAINT (body) = constraints[0];
1859 insn = emit_insn (gen_rtx_SET (VOIDmode, output_rtx[0], body));
1862 else if (noutputs == 0 && nclobbers == 0)
1864 /* No output operands: put in a raw ASM_OPERANDS rtx. */
1865 insn = emit_insn (body);
1876 body = gen_rtx_PARALLEL (VOIDmode, rtvec_alloc (num + nclobbers));
1878 /* For each output operand, store a SET. */
1879 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1881 XVECEXP (body, 0, i)
1882 = gen_rtx_SET (VOIDmode,
1884 gen_rtx_ASM_OPERANDS
1885 (GET_MODE (output_rtx[i]),
1886 TREE_STRING_POINTER (string),
1887 constraints[i], i, argvec, constraintvec,
1890 MEM_VOLATILE_P (SET_SRC (XVECEXP (body, 0, i))) = vol;
1893 /* If there are no outputs (but there are some clobbers)
1894 store the bare ASM_OPERANDS into the PARALLEL. */
1897 XVECEXP (body, 0, i++) = obody;
1899 /* Store (clobber REG) for each clobbered register specified. */
1901 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1903 const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1904 int j = decode_reg_name (regname);
1908 if (j == -3) /* `cc', which is not a register */
1911 if (j == -4) /* `memory', don't cache memory across asm */
1913 XVECEXP (body, 0, i++)
1914 = gen_rtx_CLOBBER (VOIDmode,
1917 gen_rtx_SCRATCH (VOIDmode)));
1921 /* Ignore unknown register, error already signaled. */
1925 /* Use QImode since that's guaranteed to clobber just one reg. */
1926 XVECEXP (body, 0, i++)
1927 = gen_rtx_CLOBBER (VOIDmode, gen_rtx_REG (QImode, j));
1930 insn = emit_insn (body);
1933 /* For any outputs that needed reloading into registers, spill them
1934 back to where they belong. */
1935 for (i = 0; i < noutputs; ++i)
1936 if (real_output_rtx[i])
1937 emit_move_insn (real_output_rtx[i], output_rtx[i]);
1942 /* A subroutine of expand_asm_operands. Check that all operands have
1943 the same number of alternatives. Return true if so. */
1946 check_operand_nalternatives (outputs, inputs)
1947 tree outputs, inputs;
1949 if (outputs || inputs)
1951 tree tmp = TREE_PURPOSE (outputs ? outputs : inputs);
1953 = n_occurrences (',', TREE_STRING_POINTER (TREE_VALUE (tmp)));
1956 if (nalternatives + 1 > MAX_RECOG_ALTERNATIVES)
1958 error ("too many alternatives in `asm'");
1965 const char *constraint
1966 = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tmp)));
1968 if (n_occurrences (',', constraint) != nalternatives)
1970 error ("operand constraints for `asm' differ in number of alternatives");
1974 if (TREE_CHAIN (tmp))
1975 tmp = TREE_CHAIN (tmp);
1977 tmp = next, next = 0;
1984 /* A subroutine of expand_asm_operands. Check that all operand names
1985 are unique. Return true if so. We rely on the fact that these names
1986 are identifiers, and so have been canonicalized by get_identifier,
1987 so all we need are pointer comparisons. */
1990 check_unique_operand_names (outputs, inputs)
1991 tree outputs, inputs;
1995 for (i = outputs; i ; i = TREE_CHAIN (i))
1997 tree i_name = TREE_PURPOSE (TREE_PURPOSE (i));
2001 for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
2002 if (i_name == TREE_PURPOSE (TREE_PURPOSE (j)))
2006 for (i = inputs; i ; i = TREE_CHAIN (i))
2008 tree i_name = TREE_PURPOSE (TREE_PURPOSE (i));
2012 for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
2013 if (i_name == TREE_PURPOSE (TREE_PURPOSE (j)))
2015 for (j = outputs; j ; j = TREE_CHAIN (j))
2016 if (i_name == TREE_PURPOSE (TREE_PURPOSE (j)))
2023 error ("duplicate asm operand name '%s'",
2024 IDENTIFIER_POINTER (TREE_PURPOSE (TREE_PURPOSE (i))));
2028 /* A subroutine of expand_asm_operands. Resolve the names of the operands
2029 in *POUTPUTS and *PINPUTS to numbers, and replace the name expansions in
2030 STRING and in the constraints to those numbers. */
2033 resolve_operand_names (string, outputs, inputs, pconstraints)
2035 tree outputs, inputs;
2036 const char **pconstraints;
2038 char *buffer = xstrdup (TREE_STRING_POINTER (string));
2042 /* Assume that we will not need extra space to perform the substitution.
2043 This because we get to remove '[' and ']', which means we cannot have
2044 a problem until we have more than 999 operands. */
2047 while ((p = strchr (p, '%')) != NULL)
2051 p = resolve_operand_name_1 (p, outputs, inputs);
2054 string = build_string (strlen (buffer), buffer);
2057 /* Collect output constraints here because it's convenient.
2058 There should be no named operands here; this is verified
2059 in expand_asm_operand. */
2060 for (t = outputs; t ; t = TREE_CHAIN (t), pconstraints++)
2061 *pconstraints = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
2063 /* Substitute [<name>] in input constraint strings. */
2064 for (t = inputs; t ; t = TREE_CHAIN (t), pconstraints++)
2066 const char *c = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
2067 if (strchr (c, '[') == NULL)
2071 p = buffer = xstrdup (c);
2072 while ((p = strchr (p, '[')) != NULL)
2073 p = resolve_operand_name_1 (p, outputs, inputs);
2075 *pconstraints = ggc_alloc_string (buffer, -1);
2083 /* A subroutine of resolve_operand_names. P points to the '[' for a
2084 potential named operand of the form [<name>]. In place, replace
2085 the name and brackets with a number. Return a pointer to the
2086 balance of the string after substitution. */
2089 resolve_operand_name_1 (p, outputs, inputs)
2091 tree outputs, inputs;
2098 /* Collect the operand name. */
2099 q = strchr (p, ']');
2102 error ("missing close brace for named operand");
2103 return strchr (p, '\0');
2107 /* Resolve the name to a number. */
2108 for (op = 0, t = outputs; t ; t = TREE_CHAIN (t), op++)
2110 const char *c = IDENTIFIER_POINTER (TREE_PURPOSE (TREE_PURPOSE (t)));
2111 if (strncmp (c, p + 1, len) == 0 && c[len] == '\0')
2114 for (t = inputs; t ; t = TREE_CHAIN (t), op++)
2116 const char *c = IDENTIFIER_POINTER (TREE_PURPOSE (TREE_PURPOSE (t)));
2117 if (strncmp (c, p + 1, len) == 0 && c[len] == '\0')
2122 error ("undefined named operand '%s'", p + 1);
2126 /* Replace the name with the number. Unfortunately, not all libraries
2127 get the return value of sprintf correct, so search for the end of the
2128 generated string by hand. */
2129 sprintf (p, "%d", op);
2130 p = strchr (p, '\0');
2132 /* Verify the no extra buffer space assumption. */
2136 /* Shift the rest of the buffer down to fill the gap. */
2137 memmove (p, q + 1, strlen (q + 1) + 1);
2142 /* Generate RTL to evaluate the expression EXP
2143 and remember it in case this is the VALUE in a ({... VALUE; }) constr. */
2146 expand_expr_stmt (exp)
2149 /* If -W, warn about statements with no side effects,
2150 except for an explicit cast to void (e.g. for assert()), and
2151 except inside a ({...}) where they may be useful. */
2152 if (expr_stmts_for_value == 0 && exp != error_mark_node)
2154 if (! TREE_SIDE_EFFECTS (exp))
2156 if ((extra_warnings || warn_unused_value)
2157 && !(TREE_CODE (exp) == CONVERT_EXPR
2158 && VOID_TYPE_P (TREE_TYPE (exp))))
2159 warning_with_file_and_line (emit_filename, emit_lineno,
2160 "statement with no effect");
2162 else if (warn_unused_value)
2163 warn_if_unused_value (exp);
2166 /* If EXP is of function type and we are expanding statements for
2167 value, convert it to pointer-to-function. */
2168 if (expr_stmts_for_value && TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE)
2169 exp = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (exp)), exp);
2171 /* The call to `expand_expr' could cause last_expr_type and
2172 last_expr_value to get reset. Therefore, we set last_expr_value
2173 and last_expr_type *after* calling expand_expr. */
2174 last_expr_value = expand_expr (exp,
2175 (expr_stmts_for_value
2176 ? NULL_RTX : const0_rtx),
2178 last_expr_type = TREE_TYPE (exp);
2180 /* If all we do is reference a volatile value in memory,
2181 copy it to a register to be sure it is actually touched. */
2182 if (last_expr_value != 0 && GET_CODE (last_expr_value) == MEM
2183 && TREE_THIS_VOLATILE (exp))
2185 if (TYPE_MODE (TREE_TYPE (exp)) == VOIDmode)
2187 else if (TYPE_MODE (TREE_TYPE (exp)) != BLKmode)
2188 copy_to_reg (last_expr_value);
2191 rtx lab = gen_label_rtx ();
2193 /* Compare the value with itself to reference it. */
2194 emit_cmp_and_jump_insns (last_expr_value, last_expr_value, EQ,
2195 expand_expr (TYPE_SIZE (last_expr_type),
2196 NULL_RTX, VOIDmode, 0),
2198 TYPE_ALIGN (last_expr_type) / BITS_PER_UNIT,
2204 /* If this expression is part of a ({...}) and is in memory, we may have
2205 to preserve temporaries. */
2206 preserve_temp_slots (last_expr_value);
2208 /* Free any temporaries used to evaluate this expression. Any temporary
2209 used as a result of this expression will already have been preserved
2216 /* Warn if EXP contains any computations whose results are not used.
2217 Return 1 if a warning is printed; 0 otherwise. */
2220 warn_if_unused_value (exp)
2223 if (TREE_USED (exp))
2226 /* Don't warn about void constructs. This includes casting to void,
2227 void function calls, and statement expressions with a final cast
2229 if (VOID_TYPE_P (TREE_TYPE (exp)))
2232 /* If this is an expression with side effects, don't warn. */
2233 if (TREE_SIDE_EFFECTS (exp))
2236 switch (TREE_CODE (exp))
2238 case PREINCREMENT_EXPR:
2239 case POSTINCREMENT_EXPR:
2240 case PREDECREMENT_EXPR:
2241 case POSTDECREMENT_EXPR:
2246 case METHOD_CALL_EXPR:
2248 case TRY_CATCH_EXPR:
2249 case WITH_CLEANUP_EXPR:
2254 /* For a binding, warn if no side effect within it. */
2255 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2258 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2260 case TRUTH_ORIF_EXPR:
2261 case TRUTH_ANDIF_EXPR:
2262 /* In && or ||, warn if 2nd operand has no side effect. */
2263 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2266 if (TREE_NO_UNUSED_WARNING (exp))
2268 if (warn_if_unused_value (TREE_OPERAND (exp, 0)))
2270 /* Let people do `(foo (), 0)' without a warning. */
2271 if (TREE_CONSTANT (TREE_OPERAND (exp, 1)))
2273 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2277 case NON_LVALUE_EXPR:
2278 /* Don't warn about conversions not explicit in the user's program. */
2279 if (TREE_NO_UNUSED_WARNING (exp))
2281 /* Assignment to a cast usually results in a cast of a modify.
2282 Don't complain about that. There can be an arbitrary number of
2283 casts before the modify, so we must loop until we find the first
2284 non-cast expression and then test to see if that is a modify. */
2286 tree tem = TREE_OPERAND (exp, 0);
2288 while (TREE_CODE (tem) == CONVERT_EXPR || TREE_CODE (tem) == NOP_EXPR)
2289 tem = TREE_OPERAND (tem, 0);
2291 if (TREE_CODE (tem) == MODIFY_EXPR || TREE_CODE (tem) == INIT_EXPR
2292 || TREE_CODE (tem) == CALL_EXPR)
2298 /* Don't warn about automatic dereferencing of references, since
2299 the user cannot control it. */
2300 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (exp, 0))) == REFERENCE_TYPE)
2301 return warn_if_unused_value (TREE_OPERAND (exp, 0));
2305 /* Referencing a volatile value is a side effect, so don't warn. */
2307 || TREE_CODE_CLASS (TREE_CODE (exp)) == 'r')
2308 && TREE_THIS_VOLATILE (exp))
2311 /* If this is an expression which has no operands, there is no value
2312 to be unused. There are no such language-independent codes,
2313 but front ends may define such. */
2314 if (TREE_CODE_CLASS (TREE_CODE (exp)) == 'e'
2315 && TREE_CODE_LENGTH (TREE_CODE (exp)) == 0)
2319 warning_with_file_and_line (emit_filename, emit_lineno,
2320 "value computed is not used");
2325 /* Clear out the memory of the last expression evaluated. */
2333 /* Begin a statement which will return a value.
2334 Return the RTL_EXPR for this statement expr.
2335 The caller must save that value and pass it to expand_end_stmt_expr. */
2338 expand_start_stmt_expr ()
2342 /* Make the RTL_EXPR node temporary, not momentary,
2343 so that rtl_expr_chain doesn't become garbage. */
2344 t = make_node (RTL_EXPR);
2345 do_pending_stack_adjust ();
2346 start_sequence_for_rtl_expr (t);
2348 expr_stmts_for_value++;
2352 /* Restore the previous state at the end of a statement that returns a value.
2353 Returns a tree node representing the statement's value and the
2354 insns to compute the value.
2356 The nodes of that expression have been freed by now, so we cannot use them.
2357 But we don't want to do that anyway; the expression has already been
2358 evaluated and now we just want to use the value. So generate a RTL_EXPR
2359 with the proper type and RTL value.
2361 If the last substatement was not an expression,
2362 return something with type `void'. */
2365 expand_end_stmt_expr (t)
2370 if (last_expr_type == 0)
2372 last_expr_type = void_type_node;
2373 last_expr_value = const0_rtx;
2375 else if (last_expr_value == 0)
2376 /* There are some cases where this can happen, such as when the
2377 statement is void type. */
2378 last_expr_value = const0_rtx;
2379 else if (GET_CODE (last_expr_value) != REG && ! CONSTANT_P (last_expr_value))
2380 /* Remove any possible QUEUED. */
2381 last_expr_value = protect_from_queue (last_expr_value, 0);
2385 TREE_TYPE (t) = last_expr_type;
2386 RTL_EXPR_RTL (t) = last_expr_value;
2387 RTL_EXPR_SEQUENCE (t) = get_insns ();
2389 rtl_expr_chain = tree_cons (NULL_TREE, t, rtl_expr_chain);
2393 /* Don't consider deleting this expr or containing exprs at tree level. */
2394 TREE_SIDE_EFFECTS (t) = 1;
2395 /* Propagate volatility of the actual RTL expr. */
2396 TREE_THIS_VOLATILE (t) = volatile_refs_p (last_expr_value);
2399 expr_stmts_for_value--;
2404 /* Generate RTL for the start of an if-then. COND is the expression
2405 whose truth should be tested.
2407 If EXITFLAG is nonzero, this conditional is visible to
2408 `exit_something'. */
2411 expand_start_cond (cond, exitflag)
2415 struct nesting *thiscond = ALLOC_NESTING ();
2417 /* Make an entry on cond_stack for the cond we are entering. */
2419 thiscond->next = cond_stack;
2420 thiscond->all = nesting_stack;
2421 thiscond->depth = ++nesting_depth;
2422 thiscond->data.cond.next_label = gen_label_rtx ();
2423 /* Before we encounter an `else', we don't need a separate exit label
2424 unless there are supposed to be exit statements
2425 to exit this conditional. */
2426 thiscond->exit_label = exitflag ? gen_label_rtx () : 0;
2427 thiscond->data.cond.endif_label = thiscond->exit_label;
2428 cond_stack = thiscond;
2429 nesting_stack = thiscond;
2431 do_jump (cond, thiscond->data.cond.next_label, NULL_RTX);
2434 /* Generate RTL between then-clause and the elseif-clause
2435 of an if-then-elseif-.... */
2438 expand_start_elseif (cond)
2441 if (cond_stack->data.cond.endif_label == 0)
2442 cond_stack->data.cond.endif_label = gen_label_rtx ();
2443 emit_jump (cond_stack->data.cond.endif_label);
2444 emit_label (cond_stack->data.cond.next_label);
2445 cond_stack->data.cond.next_label = gen_label_rtx ();
2446 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
2449 /* Generate RTL between the then-clause and the else-clause
2450 of an if-then-else. */
2453 expand_start_else ()
2455 if (cond_stack->data.cond.endif_label == 0)
2456 cond_stack->data.cond.endif_label = gen_label_rtx ();
2458 emit_jump (cond_stack->data.cond.endif_label);
2459 emit_label (cond_stack->data.cond.next_label);
2460 cond_stack->data.cond.next_label = 0; /* No more _else or _elseif calls. */
2463 /* After calling expand_start_else, turn this "else" into an "else if"
2464 by providing another condition. */
2467 expand_elseif (cond)
2470 cond_stack->data.cond.next_label = gen_label_rtx ();
2471 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
2474 /* Generate RTL for the end of an if-then.
2475 Pop the record for it off of cond_stack. */
2480 struct nesting *thiscond = cond_stack;
2482 do_pending_stack_adjust ();
2483 if (thiscond->data.cond.next_label)
2484 emit_label (thiscond->data.cond.next_label);
2485 if (thiscond->data.cond.endif_label)
2486 emit_label (thiscond->data.cond.endif_label);
2488 POPSTACK (cond_stack);
2492 /* Generate RTL for the start of a loop. EXIT_FLAG is nonzero if this
2493 loop should be exited by `exit_something'. This is a loop for which
2494 `expand_continue' will jump to the top of the loop.
2496 Make an entry on loop_stack to record the labels associated with
2500 expand_start_loop (exit_flag)
2503 struct nesting *thisloop = ALLOC_NESTING ();
2505 /* Make an entry on loop_stack for the loop we are entering. */
2507 thisloop->next = loop_stack;
2508 thisloop->all = nesting_stack;
2509 thisloop->depth = ++nesting_depth;
2510 thisloop->data.loop.start_label = gen_label_rtx ();
2511 thisloop->data.loop.end_label = gen_label_rtx ();
2512 thisloop->data.loop.alt_end_label = 0;
2513 thisloop->data.loop.continue_label = thisloop->data.loop.start_label;
2514 thisloop->exit_label = exit_flag ? thisloop->data.loop.end_label : 0;
2515 loop_stack = thisloop;
2516 nesting_stack = thisloop;
2518 do_pending_stack_adjust ();
2520 emit_note (NULL, NOTE_INSN_LOOP_BEG);
2521 emit_label (thisloop->data.loop.start_label);
2526 /* Like expand_start_loop but for a loop where the continuation point
2527 (for expand_continue_loop) will be specified explicitly. */
2530 expand_start_loop_continue_elsewhere (exit_flag)
2533 struct nesting *thisloop = expand_start_loop (exit_flag);
2534 loop_stack->data.loop.continue_label = gen_label_rtx ();
2538 /* Begin a null, aka do { } while (0) "loop". But since the contents
2539 of said loop can still contain a break, we must frob the loop nest. */
2542 expand_start_null_loop ()
2544 struct nesting *thisloop = ALLOC_NESTING ();
2546 /* Make an entry on loop_stack for the loop we are entering. */
2548 thisloop->next = loop_stack;
2549 thisloop->all = nesting_stack;
2550 thisloop->depth = ++nesting_depth;
2551 thisloop->data.loop.start_label = emit_note (NULL, NOTE_INSN_DELETED);
2552 thisloop->data.loop.end_label = gen_label_rtx ();
2553 thisloop->data.loop.alt_end_label = NULL_RTX;
2554 thisloop->data.loop.continue_label = thisloop->data.loop.end_label;
2555 thisloop->exit_label = thisloop->data.loop.end_label;
2556 loop_stack = thisloop;
2557 nesting_stack = thisloop;
2562 /* Specify the continuation point for a loop started with
2563 expand_start_loop_continue_elsewhere.
2564 Use this at the point in the code to which a continue statement
2568 expand_loop_continue_here ()
2570 do_pending_stack_adjust ();
2571 emit_note (NULL, NOTE_INSN_LOOP_CONT);
2572 emit_label (loop_stack->data.loop.continue_label);
2575 /* Finish a loop. Generate a jump back to the top and the loop-exit label.
2576 Pop the block off of loop_stack. */
2581 rtx start_label = loop_stack->data.loop.start_label;
2582 rtx insn = get_last_insn ();
2583 int needs_end_jump = 1;
2585 /* Mark the continue-point at the top of the loop if none elsewhere. */
2586 if (start_label == loop_stack->data.loop.continue_label)
2587 emit_note_before (NOTE_INSN_LOOP_CONT, start_label);
2589 do_pending_stack_adjust ();
2591 /* If optimizing, perhaps reorder the loop.
2592 First, try to use a condjump near the end.
2593 expand_exit_loop_if_false ends loops with unconditional jumps,
2596 if (test) goto label;
2598 goto loop_stack->data.loop.end_label
2602 If we find such a pattern, we can end the loop earlier. */
2605 && GET_CODE (insn) == CODE_LABEL
2606 && LABEL_NAME (insn) == NULL
2607 && GET_CODE (PREV_INSN (insn)) == BARRIER)
2610 rtx jump = PREV_INSN (PREV_INSN (label));
2612 if (GET_CODE (jump) == JUMP_INSN
2613 && GET_CODE (PATTERN (jump)) == SET
2614 && SET_DEST (PATTERN (jump)) == pc_rtx
2615 && GET_CODE (SET_SRC (PATTERN (jump))) == LABEL_REF
2616 && (XEXP (SET_SRC (PATTERN (jump)), 0)
2617 == loop_stack->data.loop.end_label))
2621 /* The test might be complex and reference LABEL multiple times,
2622 like the loop in loop_iterations to set vtop. To handle this,
2624 insn = PREV_INSN (label);
2625 reorder_insns (label, label, start_label);
2627 for (prev = PREV_INSN (jump);; prev = PREV_INSN (prev))
2629 /* We ignore line number notes, but if we see any other note,
2630 in particular NOTE_INSN_BLOCK_*, NOTE_INSN_EH_REGION_*,
2631 NOTE_INSN_LOOP_*, we disable this optimization. */
2632 if (GET_CODE (prev) == NOTE)
2634 if (NOTE_LINE_NUMBER (prev) < 0)
2638 if (GET_CODE (prev) == CODE_LABEL)
2640 if (GET_CODE (prev) == JUMP_INSN)
2642 if (GET_CODE (PATTERN (prev)) == SET
2643 && SET_DEST (PATTERN (prev)) == pc_rtx
2644 && GET_CODE (SET_SRC (PATTERN (prev))) == IF_THEN_ELSE
2645 && (GET_CODE (XEXP (SET_SRC (PATTERN (prev)), 1))
2647 && XEXP (XEXP (SET_SRC (PATTERN (prev)), 1), 0) == label)
2649 XEXP (XEXP (SET_SRC (PATTERN (prev)), 1), 0)
2651 emit_note_after (NOTE_INSN_LOOP_END, prev);
2660 /* If the loop starts with a loop exit, roll that to the end where
2661 it will optimize together with the jump back.
2663 We look for the conditional branch to the exit, except that once
2664 we find such a branch, we don't look past 30 instructions.
2666 In more detail, if the loop presently looks like this (in pseudo-C):
2669 if (test) goto end_label;
2674 transform it to look like:
2680 if (test) goto end_label;
2681 goto newstart_label;
2684 Here, the `test' may actually consist of some reasonably complex
2685 code, terminating in a test. */
2690 ! (GET_CODE (insn) == JUMP_INSN
2691 && GET_CODE (PATTERN (insn)) == SET
2692 && SET_DEST (PATTERN (insn)) == pc_rtx
2693 && GET_CODE (SET_SRC (PATTERN (insn))) == IF_THEN_ELSE))
2697 rtx last_test_insn = NULL_RTX;
2699 /* Scan insns from the top of the loop looking for a qualified
2700 conditional exit. */
2701 for (insn = NEXT_INSN (loop_stack->data.loop.start_label); insn;
2702 insn = NEXT_INSN (insn))
2704 if (GET_CODE (insn) == NOTE)
2707 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
2708 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
2709 /* The code that actually moves the exit test will
2710 carefully leave BLOCK notes in their original
2711 location. That means, however, that we can't debug
2712 the exit test itself. So, we refuse to move code
2713 containing BLOCK notes at low optimization levels. */
2716 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG)
2718 else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END)
2722 /* We've come to the end of an EH region, but
2723 never saw the beginning of that region. That
2724 means that an EH region begins before the top
2725 of the loop, and ends in the middle of it. The
2726 existence of such a situation violates a basic
2727 assumption in this code, since that would imply
2728 that even when EH_REGIONS is zero, we might
2729 move code out of an exception region. */
2733 /* We must not walk into a nested loop. */
2734 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)
2737 /* We already know this INSN is a NOTE, so there's no
2738 point in looking at it to see if it's a JUMP. */
2742 if (GET_CODE (insn) == JUMP_INSN || GET_CODE (insn) == INSN)
2745 if (last_test_insn && num_insns > 30)
2749 /* We don't want to move a partial EH region. Consider:
2763 This isn't legal C++, but here's what it's supposed to
2764 mean: if cond() is true, stop looping. Otherwise,
2765 call bar, and keep looping. In addition, if cond
2766 throws an exception, catch it and keep looping. Such
2767 constructs are certainy legal in LISP.
2769 We should not move the `if (cond()) 0' test since then
2770 the EH-region for the try-block would be broken up.
2771 (In this case we would the EH_BEG note for the `try'
2772 and `if cond()' but not the call to bar() or the
2775 So we don't look for tests within an EH region. */
2778 if (GET_CODE (insn) == JUMP_INSN
2779 && GET_CODE (PATTERN (insn)) == SET
2780 && SET_DEST (PATTERN (insn)) == pc_rtx)
2782 /* This is indeed a jump. */
2783 rtx dest1 = NULL_RTX;
2784 rtx dest2 = NULL_RTX;
2785 rtx potential_last_test;
2786 if (GET_CODE (SET_SRC (PATTERN (insn))) == IF_THEN_ELSE)
2788 /* A conditional jump. */
2789 dest1 = XEXP (SET_SRC (PATTERN (insn)), 1);
2790 dest2 = XEXP (SET_SRC (PATTERN (insn)), 2);
2791 potential_last_test = insn;
2795 /* An unconditional jump. */
2796 dest1 = SET_SRC (PATTERN (insn));
2797 /* Include the BARRIER after the JUMP. */
2798 potential_last_test = NEXT_INSN (insn);
2802 if (dest1 && GET_CODE (dest1) == LABEL_REF
2803 && ((XEXP (dest1, 0)
2804 == loop_stack->data.loop.alt_end_label)
2806 == loop_stack->data.loop.end_label)))
2808 last_test_insn = potential_last_test;
2812 /* If this was a conditional jump, there may be
2813 another label at which we should look. */
2820 if (last_test_insn != 0 && last_test_insn != get_last_insn ())
2822 /* We found one. Move everything from there up
2823 to the end of the loop, and add a jump into the loop
2824 to jump to there. */
2825 rtx newstart_label = gen_label_rtx ();
2826 rtx start_move = start_label;
2829 /* If the start label is preceded by a NOTE_INSN_LOOP_CONT note,
2830 then we want to move this note also. */
2831 if (GET_CODE (PREV_INSN (start_move)) == NOTE
2832 && (NOTE_LINE_NUMBER (PREV_INSN (start_move))
2833 == NOTE_INSN_LOOP_CONT))
2834 start_move = PREV_INSN (start_move);
2836 emit_label_after (newstart_label, PREV_INSN (start_move));
2838 /* Actually move the insns. Start at the beginning, and
2839 keep copying insns until we've copied the
2841 for (insn = start_move; insn; insn = next_insn)
2843 /* Figure out which insn comes after this one. We have
2844 to do this before we move INSN. */
2845 if (insn == last_test_insn)
2846 /* We've moved all the insns. */
2847 next_insn = NULL_RTX;
2849 next_insn = NEXT_INSN (insn);
2851 if (GET_CODE (insn) == NOTE
2852 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
2853 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
2854 /* We don't want to move NOTE_INSN_BLOCK_BEGs or
2855 NOTE_INSN_BLOCK_ENDs because the correct generation
2856 of debugging information depends on these appearing
2857 in the same order in the RTL and in the tree
2858 structure, where they are represented as BLOCKs.
2859 So, we don't move block notes. Of course, moving
2860 the code inside the block is likely to make it
2861 impossible to debug the instructions in the exit
2862 test, but such is the price of optimization. */
2865 /* Move the INSN. */
2866 reorder_insns (insn, insn, get_last_insn ());
2869 emit_jump_insn_after (gen_jump (start_label),
2870 PREV_INSN (newstart_label));
2871 emit_barrier_after (PREV_INSN (newstart_label));
2872 start_label = newstart_label;
2878 emit_jump (start_label);
2879 emit_note (NULL, NOTE_INSN_LOOP_END);
2881 emit_label (loop_stack->data.loop.end_label);
2883 POPSTACK (loop_stack);
2888 /* Finish a null loop, aka do { } while (0). */
2891 expand_end_null_loop ()
2893 do_pending_stack_adjust ();
2894 emit_label (loop_stack->data.loop.end_label);
2896 POPSTACK (loop_stack);
2901 /* Generate a jump to the current loop's continue-point.
2902 This is usually the top of the loop, but may be specified
2903 explicitly elsewhere. If not currently inside a loop,
2904 return 0 and do nothing; caller will print an error message. */
2907 expand_continue_loop (whichloop)
2908 struct nesting *whichloop;
2912 whichloop = loop_stack;
2915 expand_goto_internal (NULL_TREE, whichloop->data.loop.continue_label,
2920 /* Generate a jump to exit the current loop. If not currently inside a loop,
2921 return 0 and do nothing; caller will print an error message. */
2924 expand_exit_loop (whichloop)
2925 struct nesting *whichloop;
2929 whichloop = loop_stack;
2932 expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label, NULL_RTX);
2936 /* Generate a conditional jump to exit the current loop if COND
2937 evaluates to zero. If not currently inside a loop,
2938 return 0 and do nothing; caller will print an error message. */
2941 expand_exit_loop_if_false (whichloop, cond)
2942 struct nesting *whichloop;
2945 rtx label = gen_label_rtx ();
2950 whichloop = loop_stack;
2953 /* In order to handle fixups, we actually create a conditional jump
2954 around an unconditional branch to exit the loop. If fixups are
2955 necessary, they go before the unconditional branch. */
2957 do_jump (cond, NULL_RTX, label);
2958 last_insn = get_last_insn ();
2959 if (GET_CODE (last_insn) == CODE_LABEL)
2960 whichloop->data.loop.alt_end_label = last_insn;
2961 expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label,
2968 /* Return nonzero if the loop nest is empty. Else return zero. */
2971 stmt_loop_nest_empty ()
2973 /* cfun->stmt can be NULL if we are building a call to get the
2974 EH context for a setjmp/longjmp EH target and the current
2975 function was a deferred inline function. */
2976 return (cfun->stmt == NULL || loop_stack == NULL);
2979 /* Return non-zero if we should preserve sub-expressions as separate
2980 pseudos. We never do so if we aren't optimizing. We always do so
2981 if -fexpensive-optimizations.
2983 Otherwise, we only do so if we are in the "early" part of a loop. I.e.,
2984 the loop may still be a small one. */
2987 preserve_subexpressions_p ()
2991 if (flag_expensive_optimizations)
2994 if (optimize == 0 || cfun == 0 || cfun->stmt == 0 || loop_stack == 0)
2997 insn = get_last_insn_anywhere ();
3000 && (INSN_UID (insn) - INSN_UID (loop_stack->data.loop.start_label)
3001 < n_non_fixed_regs * 3));
3005 /* Generate a jump to exit the current loop, conditional, binding contour
3006 or case statement. Not all such constructs are visible to this function,
3007 only those started with EXIT_FLAG nonzero. Individual languages use
3008 the EXIT_FLAG parameter to control which kinds of constructs you can
3011 If not currently inside anything that can be exited,
3012 return 0 and do nothing; caller will print an error message. */
3015 expand_exit_something ()
3019 for (n = nesting_stack; n; n = n->all)
3020 if (n->exit_label != 0)
3022 expand_goto_internal (NULL_TREE, n->exit_label, NULL_RTX);
3029 /* Generate RTL to return from the current function, with no value.
3030 (That is, we do not do anything about returning any value.) */
3033 expand_null_return ()
3035 rtx last_insn = get_last_insn ();
3037 /* If this function was declared to return a value, but we
3038 didn't, clobber the return registers so that they are not
3039 propogated live to the rest of the function. */
3040 clobber_return_register ();
3042 expand_null_return_1 (last_insn);
3045 /* Generate RTL to return from the current function, with value VAL. */
3048 expand_value_return (val)
3051 rtx last_insn = get_last_insn ();
3052 rtx return_reg = DECL_RTL (DECL_RESULT (current_function_decl));
3054 /* Copy the value to the return location
3055 unless it's already there. */
3057 if (return_reg != val)
3059 tree type = TREE_TYPE (DECL_RESULT (current_function_decl));
3060 #ifdef PROMOTE_FUNCTION_RETURN
3061 int unsignedp = TREE_UNSIGNED (type);
3062 enum machine_mode old_mode
3063 = DECL_MODE (DECL_RESULT (current_function_decl));
3064 enum machine_mode mode
3065 = promote_mode (type, old_mode, &unsignedp, 1);
3067 if (mode != old_mode)
3068 val = convert_modes (mode, old_mode, val, unsignedp);
3070 if (GET_CODE (return_reg) == PARALLEL)
3071 emit_group_load (return_reg, val, int_size_in_bytes (type),
3074 emit_move_insn (return_reg, val);
3077 expand_null_return_1 (last_insn);
3080 /* Output a return with no value. If LAST_INSN is nonzero,
3081 pretend that the return takes place after LAST_INSN. */
3084 expand_null_return_1 (last_insn)
3087 rtx end_label = cleanup_label ? cleanup_label : return_label;
3089 clear_pending_stack_adjust ();
3090 do_pending_stack_adjust ();
3094 end_label = return_label = gen_label_rtx ();
3095 expand_goto_internal (NULL_TREE, end_label, last_insn);
3098 /* Generate RTL to evaluate the expression RETVAL and return it
3099 from the current function. */
3102 expand_return (retval)
3105 /* If there are any cleanups to be performed, then they will
3106 be inserted following LAST_INSN. It is desirable
3107 that the last_insn, for such purposes, should be the
3108 last insn before computing the return value. Otherwise, cleanups
3109 which call functions can clobber the return value. */
3110 /* ??? rms: I think that is erroneous, because in C++ it would
3111 run destructors on variables that might be used in the subsequent
3112 computation of the return value. */
3118 /* If function wants no value, give it none. */
3119 if (TREE_CODE (TREE_TYPE (TREE_TYPE (current_function_decl))) == VOID_TYPE)
3121 expand_expr (retval, NULL_RTX, VOIDmode, 0);
3123 expand_null_return ();
3127 if (retval == error_mark_node)
3129 /* Treat this like a return of no value from a function that
3131 expand_null_return ();
3134 else if (TREE_CODE (retval) == RESULT_DECL)
3135 retval_rhs = retval;
3136 else if ((TREE_CODE (retval) == MODIFY_EXPR || TREE_CODE (retval) == INIT_EXPR)
3137 && TREE_CODE (TREE_OPERAND (retval, 0)) == RESULT_DECL)
3138 retval_rhs = TREE_OPERAND (retval, 1);
3139 else if (VOID_TYPE_P (TREE_TYPE (retval)))
3140 /* Recognize tail-recursive call to void function. */
3141 retval_rhs = retval;
3143 retval_rhs = NULL_TREE;
3145 last_insn = get_last_insn ();
3147 /* Distribute return down conditional expr if either of the sides
3148 may involve tail recursion (see test below). This enhances the number
3149 of tail recursions we see. Don't do this always since it can produce
3150 sub-optimal code in some cases and we distribute assignments into
3151 conditional expressions when it would help. */
3153 if (optimize && retval_rhs != 0
3154 && frame_offset == 0
3155 && TREE_CODE (retval_rhs) == COND_EXPR
3156 && (TREE_CODE (TREE_OPERAND (retval_rhs, 1)) == CALL_EXPR
3157 || TREE_CODE (TREE_OPERAND (retval_rhs, 2)) == CALL_EXPR))
3159 rtx label = gen_label_rtx ();
3162 do_jump (TREE_OPERAND (retval_rhs, 0), label, NULL_RTX);
3163 start_cleanup_deferral ();
3164 expr = build (MODIFY_EXPR, TREE_TYPE (TREE_TYPE (current_function_decl)),
3165 DECL_RESULT (current_function_decl),
3166 TREE_OPERAND (retval_rhs, 1));
3167 TREE_SIDE_EFFECTS (expr) = 1;
3168 expand_return (expr);
3171 expr = build (MODIFY_EXPR, TREE_TYPE (TREE_TYPE (current_function_decl)),
3172 DECL_RESULT (current_function_decl),
3173 TREE_OPERAND (retval_rhs, 2));
3174 TREE_SIDE_EFFECTS (expr) = 1;
3175 expand_return (expr);
3176 end_cleanup_deferral ();
3180 result_rtl = DECL_RTL (DECL_RESULT (current_function_decl));
3182 /* If the result is an aggregate that is being returned in one (or more)
3183 registers, load the registers here. The compiler currently can't handle
3184 copying a BLKmode value into registers. We could put this code in a
3185 more general area (for use by everyone instead of just function
3186 call/return), but until this feature is generally usable it is kept here
3187 (and in expand_call). The value must go into a pseudo in case there
3188 are cleanups that will clobber the real return register. */
3191 && TYPE_MODE (TREE_TYPE (retval_rhs)) == BLKmode
3192 && GET_CODE (result_rtl) == REG)
3195 unsigned HOST_WIDE_INT bitpos, xbitpos;
3196 unsigned HOST_WIDE_INT big_endian_correction = 0;
3197 unsigned HOST_WIDE_INT bytes
3198 = int_size_in_bytes (TREE_TYPE (retval_rhs));
3199 int n_regs = (bytes + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
3200 unsigned int bitsize
3201 = MIN (TYPE_ALIGN (TREE_TYPE (retval_rhs)), BITS_PER_WORD);
3202 rtx *result_pseudos = (rtx *) alloca (sizeof (rtx) * n_regs);
3203 rtx result_reg, src = NULL_RTX, dst = NULL_RTX;
3204 rtx result_val = expand_expr (retval_rhs, NULL_RTX, VOIDmode, 0);
3205 enum machine_mode tmpmode, result_reg_mode;
3209 expand_null_return ();
3213 /* Structures whose size is not a multiple of a word are aligned
3214 to the least significant byte (to the right). On a BYTES_BIG_ENDIAN
3215 machine, this means we must skip the empty high order bytes when
3216 calculating the bit offset. */
3217 if (BYTES_BIG_ENDIAN && bytes % UNITS_PER_WORD)
3218 big_endian_correction = (BITS_PER_WORD - ((bytes % UNITS_PER_WORD)
3221 /* Copy the structure BITSIZE bits at a time. */
3222 for (bitpos = 0, xbitpos = big_endian_correction;
3223 bitpos < bytes * BITS_PER_UNIT;
3224 bitpos += bitsize, xbitpos += bitsize)
3226 /* We need a new destination pseudo each time xbitpos is
3227 on a word boundary and when xbitpos == big_endian_correction
3228 (the first time through). */
3229 if (xbitpos % BITS_PER_WORD == 0
3230 || xbitpos == big_endian_correction)
3232 /* Generate an appropriate register. */
3233 dst = gen_reg_rtx (word_mode);
3234 result_pseudos[xbitpos / BITS_PER_WORD] = dst;
3236 /* Clobber the destination before we move anything into it. */
3237 emit_insn (gen_rtx_CLOBBER (VOIDmode, dst));
3240 /* We need a new source operand each time bitpos is on a word
3242 if (bitpos % BITS_PER_WORD == 0)
3243 src = operand_subword_force (result_val,
3244 bitpos / BITS_PER_WORD,
3247 /* Use bitpos for the source extraction (left justified) and
3248 xbitpos for the destination store (right justified). */
3249 store_bit_field (dst, bitsize, xbitpos % BITS_PER_WORD, word_mode,
3250 extract_bit_field (src, bitsize,
3251 bitpos % BITS_PER_WORD, 1,
3252 NULL_RTX, word_mode, word_mode,
3253 bitsize, BITS_PER_WORD),
3254 bitsize, BITS_PER_WORD);
3257 /* Find the smallest integer mode large enough to hold the
3258 entire structure and use that mode instead of BLKmode
3259 on the USE insn for the return register. */
3260 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
3261 tmpmode != VOIDmode;
3262 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
3263 /* Have we found a large enough mode? */
3264 if (GET_MODE_SIZE (tmpmode) >= bytes)
3267 /* No suitable mode found. */
3268 if (tmpmode == VOIDmode)
3271 PUT_MODE (result_rtl, tmpmode);
3273 if (GET_MODE_SIZE (tmpmode) < GET_MODE_SIZE (word_mode))
3274 result_reg_mode = word_mode;
3276 result_reg_mode = tmpmode;
3277 result_reg = gen_reg_rtx (result_reg_mode);
3280 for (i = 0; i < n_regs; i++)
3281 emit_move_insn (operand_subword (result_reg, i, 0, result_reg_mode),
3284 if (tmpmode != result_reg_mode)
3285 result_reg = gen_lowpart (tmpmode, result_reg);
3287 expand_value_return (result_reg);
3289 else if (retval_rhs != 0
3290 && !VOID_TYPE_P (TREE_TYPE (retval_rhs))
3291 && (GET_CODE (result_rtl) == REG
3292 || (GET_CODE (result_rtl) == PARALLEL)))
3294 /* Calculate the return value into a temporary (usually a pseudo
3296 tree ot = TREE_TYPE (DECL_RESULT (current_function_decl));
3297 tree nt = build_qualified_type (ot, TYPE_QUALS (ot) | TYPE_QUAL_CONST);
3299 val = assign_temp (nt, 0, 0, 1);
3300 val = expand_expr (retval_rhs, val, GET_MODE (val), 0);
3301 val = force_not_mem (val);
3303 /* Return the calculated value, doing cleanups first. */
3304 expand_value_return (val);
3308 /* No cleanups or no hard reg used;
3309 calculate value into hard return reg. */
3310 expand_expr (retval, const0_rtx, VOIDmode, 0);
3312 expand_value_return (result_rtl);
3316 /* Return 1 if the end of the generated RTX is not a barrier.
3317 This means code already compiled can drop through. */
3320 drop_through_at_end_p ()
3322 rtx insn = get_last_insn ();
3323 while (insn && GET_CODE (insn) == NOTE)
3324 insn = PREV_INSN (insn);
3325 return insn && GET_CODE (insn) != BARRIER;
3328 /* Attempt to optimize a potential tail recursion call into a goto.
3329 ARGUMENTS are the arguments to a CALL_EXPR; LAST_INSN indicates
3330 where to place the jump to the tail recursion label.
3332 Return TRUE if the call was optimized into a goto. */
3335 optimize_tail_recursion (arguments, last_insn)
3339 /* Finish checking validity, and if valid emit code to set the
3340 argument variables for the new call. */
3341 if (tail_recursion_args (arguments, DECL_ARGUMENTS (current_function_decl)))
3343 if (tail_recursion_label == 0)
3345 tail_recursion_label = gen_label_rtx ();
3346 emit_label_after (tail_recursion_label,
3347 tail_recursion_reentry);
3350 expand_goto_internal (NULL_TREE, tail_recursion_label, last_insn);
3357 /* Emit code to alter this function's formal parms for a tail-recursive call.
3358 ACTUALS is a list of actual parameter expressions (chain of TREE_LISTs).
3359 FORMALS is the chain of decls of formals.
3360 Return 1 if this can be done;
3361 otherwise return 0 and do not emit any code. */
3364 tail_recursion_args (actuals, formals)
3365 tree actuals, formals;
3367 tree a = actuals, f = formals;
3371 /* Check that number and types of actuals are compatible
3372 with the formals. This is not always true in valid C code.
3373 Also check that no formal needs to be addressable
3374 and that all formals are scalars. */
3376 /* Also count the args. */
3378 for (a = actuals, f = formals, i = 0; a && f; a = TREE_CHAIN (a), f = TREE_CHAIN (f), i++)
3380 if (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_VALUE (a)))
3381 != TYPE_MAIN_VARIANT (TREE_TYPE (f)))
3383 if (GET_CODE (DECL_RTL (f)) != REG || DECL_MODE (f) == BLKmode)
3386 if (a != 0 || f != 0)
3389 /* Compute all the actuals. */
3391 argvec = (rtx *) alloca (i * sizeof (rtx));
3393 for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
3394 argvec[i] = expand_expr (TREE_VALUE (a), NULL_RTX, VOIDmode, 0);
3396 /* Find which actual values refer to current values of previous formals.
3397 Copy each of them now, before any formal is changed. */
3399 for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
3403 for (f = formals, j = 0; j < i; f = TREE_CHAIN (f), j++)
3404 if (reg_mentioned_p (DECL_RTL (f), argvec[i]))
3410 argvec[i] = copy_to_reg (argvec[i]);
3413 /* Store the values of the actuals into the formals. */
3415 for (f = formals, a = actuals, i = 0; f;
3416 f = TREE_CHAIN (f), a = TREE_CHAIN (a), i++)
3418 if (GET_MODE (DECL_RTL (f)) == GET_MODE (argvec[i]))
3419 emit_move_insn (DECL_RTL (f), argvec[i]);
3421 convert_move (DECL_RTL (f), argvec[i],
3422 TREE_UNSIGNED (TREE_TYPE (TREE_VALUE (a))));
3429 /* Generate the RTL code for entering a binding contour.
3430 The variables are declared one by one, by calls to `expand_decl'.
3432 FLAGS is a bitwise or of the following flags:
3434 1 - Nonzero if this construct should be visible to
3437 2 - Nonzero if this contour does not require a
3438 NOTE_INSN_BLOCK_BEG note. Virtually all calls from
3439 language-independent code should set this flag because they
3440 will not create corresponding BLOCK nodes. (There should be
3441 a one-to-one correspondence between NOTE_INSN_BLOCK_BEG notes
3442 and BLOCKs.) If this flag is set, MARK_ENDS should be zero
3443 when expand_end_bindings is called.
3445 If we are creating a NOTE_INSN_BLOCK_BEG note, a BLOCK may
3446 optionally be supplied. If so, it becomes the NOTE_BLOCK for the
3450 expand_start_bindings_and_block (flags, block)
3454 struct nesting *thisblock = ALLOC_NESTING ();
3456 int exit_flag = ((flags & 1) != 0);
3457 int block_flag = ((flags & 2) == 0);
3459 /* If a BLOCK is supplied, then the caller should be requesting a
3460 NOTE_INSN_BLOCK_BEG note. */
3461 if (!block_flag && block)
3464 /* Create a note to mark the beginning of the block. */
3467 note = emit_note (NULL, NOTE_INSN_BLOCK_BEG);
3468 NOTE_BLOCK (note) = block;
3471 note = emit_note (NULL, NOTE_INSN_DELETED);
3473 /* Make an entry on block_stack for the block we are entering. */
3475 thisblock->next = block_stack;
3476 thisblock->all = nesting_stack;
3477 thisblock->depth = ++nesting_depth;
3478 thisblock->data.block.stack_level = 0;
3479 thisblock->data.block.cleanups = 0;
3480 thisblock->data.block.n_function_calls = 0;
3481 thisblock->data.block.exception_region = 0;
3482 thisblock->data.block.block_target_temp_slot_level = target_temp_slot_level;
3484 thisblock->data.block.conditional_code = 0;
3485 thisblock->data.block.last_unconditional_cleanup = note;
3486 /* When we insert instructions after the last unconditional cleanup,
3487 we don't adjust last_insn. That means that a later add_insn will
3488 clobber the instructions we've just added. The easiest way to
3489 fix this is to just insert another instruction here, so that the
3490 instructions inserted after the last unconditional cleanup are
3491 never the last instruction. */
3492 emit_note (NULL, NOTE_INSN_DELETED);
3493 thisblock->data.block.cleanup_ptr = &thisblock->data.block.cleanups;
3496 && !(block_stack->data.block.cleanups == NULL_TREE
3497 && block_stack->data.block.outer_cleanups == NULL_TREE))
3498 thisblock->data.block.outer_cleanups
3499 = tree_cons (NULL_TREE, block_stack->data.block.cleanups,
3500 block_stack->data.block.outer_cleanups);
3502 thisblock->data.block.outer_cleanups = 0;
3503 thisblock->data.block.label_chain = 0;
3504 thisblock->data.block.innermost_stack_block = stack_block_stack;
3505 thisblock->data.block.first_insn = note;
3506 thisblock->data.block.block_start_count = ++current_block_start_count;
3507 thisblock->exit_label = exit_flag ? gen_label_rtx () : 0;
3508 block_stack = thisblock;
3509 nesting_stack = thisblock;
3511 /* Make a new level for allocating stack slots. */
3515 /* Specify the scope of temporaries created by TARGET_EXPRs. Similar
3516 to CLEANUP_POINT_EXPR, but handles cases when a series of calls to
3517 expand_expr are made. After we end the region, we know that all
3518 space for all temporaries that were created by TARGET_EXPRs will be
3519 destroyed and their space freed for reuse. */
3522 expand_start_target_temps ()
3524 /* This is so that even if the result is preserved, the space
3525 allocated will be freed, as we know that it is no longer in use. */
3528 /* Start a new binding layer that will keep track of all cleanup
3529 actions to be performed. */
3530 expand_start_bindings (2);
3532 target_temp_slot_level = temp_slot_level;
3536 expand_end_target_temps ()
3538 expand_end_bindings (NULL_TREE, 0, 0);
3540 /* This is so that even if the result is preserved, the space
3541 allocated will be freed, as we know that it is no longer in use. */
3545 /* Given a pointer to a BLOCK node return non-zero if (and only if) the node
3546 in question represents the outermost pair of curly braces (i.e. the "body
3547 block") of a function or method.
3549 For any BLOCK node representing a "body block" of a function or method, the
3550 BLOCK_SUPERCONTEXT of the node will point to another BLOCK node which
3551 represents the outermost (function) scope for the function or method (i.e.
3552 the one which includes the formal parameters). The BLOCK_SUPERCONTEXT of
3553 *that* node in turn will point to the relevant FUNCTION_DECL node. */
3556 is_body_block (stmt)
3559 if (TREE_CODE (stmt) == BLOCK)
3561 tree parent = BLOCK_SUPERCONTEXT (stmt);
3563 if (parent && TREE_CODE (parent) == BLOCK)
3565 tree grandparent = BLOCK_SUPERCONTEXT (parent);
3567 if (grandparent && TREE_CODE (grandparent) == FUNCTION_DECL)
3575 /* True if we are currently emitting insns in an area of output code
3576 that is controlled by a conditional expression. This is used by
3577 the cleanup handling code to generate conditional cleanup actions. */
3580 conditional_context ()
3582 return block_stack && block_stack->data.block.conditional_code;
3585 /* Return an opaque pointer to the current nesting level, so frontend code
3586 can check its own sanity. */
3589 current_nesting_level ()
3591 return cfun ? block_stack : 0;
3594 /* Emit a handler label for a nonlocal goto handler.
3595 Also emit code to store the handler label in SLOT before BEFORE_INSN. */
3598 expand_nl_handler_label (slot, before_insn)
3599 rtx slot, before_insn;
3602 rtx handler_label = gen_label_rtx ();
3604 /* Don't let cleanup_cfg delete the handler. */
3605 LABEL_PRESERVE_P (handler_label) = 1;
3608 emit_move_insn (slot, gen_rtx_LABEL_REF (Pmode, handler_label));
3609 insns = get_insns ();
3611 emit_insns_before (insns, before_insn);
3613 emit_label (handler_label);
3615 return handler_label;
3618 /* Emit code to restore vital registers at the beginning of a nonlocal goto
3621 expand_nl_goto_receiver ()
3623 #ifdef HAVE_nonlocal_goto
3624 if (! HAVE_nonlocal_goto)
3626 /* First adjust our frame pointer to its actual value. It was
3627 previously set to the start of the virtual area corresponding to
3628 the stacked variables when we branched here and now needs to be
3629 adjusted to the actual hardware fp value.
3631 Assignments are to virtual registers are converted by
3632 instantiate_virtual_regs into the corresponding assignment
3633 to the underlying register (fp in this case) that makes
3634 the original assignment true.
3635 So the following insn will actually be
3636 decrementing fp by STARTING_FRAME_OFFSET. */
3637 emit_move_insn (virtual_stack_vars_rtx, hard_frame_pointer_rtx);
3639 #if ARG_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3640 if (fixed_regs[ARG_POINTER_REGNUM])
3642 #ifdef ELIMINABLE_REGS
3643 /* If the argument pointer can be eliminated in favor of the
3644 frame pointer, we don't need to restore it. We assume here
3645 that if such an elimination is present, it can always be used.
3646 This is the case on all known machines; if we don't make this
3647 assumption, we do unnecessary saving on many machines. */
3648 static const struct elims {const int from, to;} elim_regs[] = ELIMINABLE_REGS;
3651 for (i = 0; i < ARRAY_SIZE (elim_regs); i++)
3652 if (elim_regs[i].from == ARG_POINTER_REGNUM
3653 && elim_regs[i].to == HARD_FRAME_POINTER_REGNUM)
3656 if (i == ARRAY_SIZE (elim_regs))
3659 /* Now restore our arg pointer from the address at which it
3660 was saved in our stack frame. */
3661 emit_move_insn (virtual_incoming_args_rtx,
3662 copy_to_reg (get_arg_pointer_save_area (cfun)));
3667 #ifdef HAVE_nonlocal_goto_receiver
3668 if (HAVE_nonlocal_goto_receiver)
3669 emit_insn (gen_nonlocal_goto_receiver ());
3673 /* Make handlers for nonlocal gotos taking place in the function calls in
3677 expand_nl_goto_receivers (thisblock)
3678 struct nesting *thisblock;
3681 rtx afterward = gen_label_rtx ();
3686 /* Record the handler address in the stack slot for that purpose,
3687 during this block, saving and restoring the outer value. */
3688 if (thisblock->next != 0)
3689 for (slot = nonlocal_goto_handler_slots; slot; slot = XEXP (slot, 1))
3691 rtx save_receiver = gen_reg_rtx (Pmode);
3692 emit_move_insn (XEXP (slot, 0), save_receiver);
3695 emit_move_insn (save_receiver, XEXP (slot, 0));
3696 insns = get_insns ();
3698 emit_insns_before (insns, thisblock->data.block.first_insn);
3701 /* Jump around the handlers; they run only when specially invoked. */
3702 emit_jump (afterward);
3704 /* Make a separate handler for each label. */
3705 link = nonlocal_labels;
3706 slot = nonlocal_goto_handler_slots;
3707 label_list = NULL_RTX;
3708 for (; link; link = TREE_CHAIN (link), slot = XEXP (slot, 1))
3709 /* Skip any labels we shouldn't be able to jump to from here,
3710 we generate one special handler for all of them below which just calls
3712 if (! DECL_TOO_LATE (TREE_VALUE (link)))
3715 lab = expand_nl_handler_label (XEXP (slot, 0),
3716 thisblock->data.block.first_insn);
3717 label_list = gen_rtx_EXPR_LIST (VOIDmode, lab, label_list);
3719 expand_nl_goto_receiver ();
3721 /* Jump to the "real" nonlocal label. */
3722 expand_goto (TREE_VALUE (link));
3725 /* A second pass over all nonlocal labels; this time we handle those
3726 we should not be able to jump to at this point. */
3727 link = nonlocal_labels;
3728 slot = nonlocal_goto_handler_slots;
3730 for (; link; link = TREE_CHAIN (link), slot = XEXP (slot, 1))
3731 if (DECL_TOO_LATE (TREE_VALUE (link)))
3734 lab = expand_nl_handler_label (XEXP (slot, 0),
3735 thisblock->data.block.first_insn);
3736 label_list = gen_rtx_EXPR_LIST (VOIDmode, lab, label_list);
3742 expand_nl_goto_receiver ();
3743 emit_library_call (gen_rtx_SYMBOL_REF (Pmode, "abort"), 0,
3748 nonlocal_goto_handler_labels = label_list;
3749 emit_label (afterward);
3752 /* Warn about any unused VARS (which may contain nodes other than
3753 VAR_DECLs, but such nodes are ignored). The nodes are connected
3754 via the TREE_CHAIN field. */
3757 warn_about_unused_variables (vars)
3762 if (warn_unused_variable)
3763 for (decl = vars; decl; decl = TREE_CHAIN (decl))
3764 if (TREE_CODE (decl) == VAR_DECL
3765 && ! TREE_USED (decl)
3766 && ! DECL_IN_SYSTEM_HEADER (decl)
3767 && DECL_NAME (decl) && ! DECL_ARTIFICIAL (decl))
3768 warning_with_decl (decl, "unused variable `%s'");
3771 /* Generate RTL code to terminate a binding contour.
3773 VARS is the chain of VAR_DECL nodes for the variables bound in this
3774 contour. There may actually be other nodes in this chain, but any
3775 nodes other than VAR_DECLS are ignored.
3777 MARK_ENDS is nonzero if we should put a note at the beginning
3778 and end of this binding contour.
3780 DONT_JUMP_IN is nonzero if it is not valid to jump into this contour.
3781 (That is true automatically if the contour has a saved stack level.) */
3784 expand_end_bindings (vars, mark_ends, dont_jump_in)
3789 struct nesting *thisblock = block_stack;
3791 /* If any of the variables in this scope were not used, warn the
3793 warn_about_unused_variables (vars);
3795 if (thisblock->exit_label)
3797 do_pending_stack_adjust ();
3798 emit_label (thisblock->exit_label);
3801 /* If necessary, make handlers for nonlocal gotos taking
3802 place in the function calls in this block. */
3803 if (function_call_count != thisblock->data.block.n_function_calls
3805 /* Make handler for outermost block
3806 if there were any nonlocal gotos to this function. */
3807 && (thisblock->next == 0 ? current_function_has_nonlocal_label
3808 /* Make handler for inner block if it has something
3809 special to do when you jump out of it. */
3810 : (thisblock->data.block.cleanups != 0
3811 || thisblock->data.block.stack_level != 0)))
3812 expand_nl_goto_receivers (thisblock);
3814 /* Don't allow jumping into a block that has a stack level.
3815 Cleanups are allowed, though. */
3817 || thisblock->data.block.stack_level != 0)
3819 struct label_chain *chain;
3821 /* Any labels in this block are no longer valid to go to.
3822 Mark them to cause an error message. */
3823 for (chain = thisblock->data.block.label_chain; chain; chain = chain->next)
3825 DECL_TOO_LATE (chain->label) = 1;
3826 /* If any goto without a fixup came to this label,
3827 that must be an error, because gotos without fixups
3828 come from outside all saved stack-levels. */
3829 if (TREE_ADDRESSABLE (chain->label))
3830 error_with_decl (chain->label,
3831 "label `%s' used before containing binding contour");
3835 /* Restore stack level in effect before the block
3836 (only if variable-size objects allocated). */
3837 /* Perform any cleanups associated with the block. */
3839 if (thisblock->data.block.stack_level != 0
3840 || thisblock->data.block.cleanups != 0)
3845 /* Don't let cleanups affect ({...}) constructs. */
3846 int old_expr_stmts_for_value = expr_stmts_for_value;
3847 rtx old_last_expr_value = last_expr_value;
3848 tree old_last_expr_type = last_expr_type;
3849 expr_stmts_for_value = 0;
3851 /* Only clean up here if this point can actually be reached. */
3852 insn = get_last_insn ();
3853 if (GET_CODE (insn) == NOTE)
3854 insn = prev_nonnote_insn (insn);
3855 reachable = (! insn || GET_CODE (insn) != BARRIER);
3857 /* Do the cleanups. */
3858 expand_cleanups (thisblock->data.block.cleanups, NULL_TREE, 0, reachable);
3860 do_pending_stack_adjust ();
3862 expr_stmts_for_value = old_expr_stmts_for_value;
3863 last_expr_value = old_last_expr_value;
3864 last_expr_type = old_last_expr_type;
3866 /* Restore the stack level. */
3868 if (reachable && thisblock->data.block.stack_level != 0)
3870 emit_stack_restore (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3871 thisblock->data.block.stack_level, NULL_RTX);
3872 if (nonlocal_goto_handler_slots != 0)
3873 emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level,
3877 /* Any gotos out of this block must also do these things.
3878 Also report any gotos with fixups that came to labels in this
3880 fixup_gotos (thisblock,
3881 thisblock->data.block.stack_level,
3882 thisblock->data.block.cleanups,
3883 thisblock->data.block.first_insn,
3887 /* Mark the beginning and end of the scope if requested.
3888 We do this now, after running cleanups on the variables
3889 just going out of scope, so they are in scope for their cleanups. */
3893 rtx note = emit_note (NULL, NOTE_INSN_BLOCK_END);
3894 NOTE_BLOCK (note) = NOTE_BLOCK (thisblock->data.block.first_insn);
3897 /* Get rid of the beginning-mark if we don't make an end-mark. */
3898 NOTE_LINE_NUMBER (thisblock->data.block.first_insn) = NOTE_INSN_DELETED;
3900 /* Restore the temporary level of TARGET_EXPRs. */
3901 target_temp_slot_level = thisblock->data.block.block_target_temp_slot_level;
3903 /* Restore block_stack level for containing block. */
3905 stack_block_stack = thisblock->data.block.innermost_stack_block;
3906 POPSTACK (block_stack);
3908 /* Pop the stack slot nesting and free any slots at this level. */
3912 /* Generate code to save the stack pointer at the start of the current block
3913 and set up to restore it on exit. */
3916 save_stack_pointer ()
3918 struct nesting *thisblock = block_stack;
3920 if (thisblock->data.block.stack_level == 0)
3922 emit_stack_save (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3923 &thisblock->data.block.stack_level,
3924 thisblock->data.block.first_insn);
3925 stack_block_stack = thisblock;
3929 /* Generate RTL for the automatic variable declaration DECL.
3930 (Other kinds of declarations are simply ignored if seen here.) */
3936 struct nesting *thisblock;
3939 type = TREE_TYPE (decl);
3941 /* For a CONST_DECL, set mode, alignment, and sizes from those of the
3942 type in case this node is used in a reference. */
3943 if (TREE_CODE (decl) == CONST_DECL)
3945 DECL_MODE (decl) = TYPE_MODE (type);
3946 DECL_ALIGN (decl) = TYPE_ALIGN (type);
3947 DECL_SIZE (decl) = TYPE_SIZE (type);
3948 DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (type);
3952 /* Otherwise, only automatic variables need any expansion done. Static and
3953 external variables, and external functions, will be handled by
3954 `assemble_variable' (called from finish_decl). TYPE_DECL requires
3955 nothing. PARM_DECLs are handled in `assign_parms'. */
3956 if (TREE_CODE (decl) != VAR_DECL)
3959 if (TREE_STATIC (decl) || DECL_EXTERNAL (decl))
3962 thisblock = block_stack;
3964 /* Create the RTL representation for the variable. */
3966 if (type == error_mark_node)
3967 SET_DECL_RTL (decl, gen_rtx_MEM (BLKmode, const0_rtx));
3969 else if (DECL_SIZE (decl) == 0)
3970 /* Variable with incomplete type. */
3973 if (DECL_INITIAL (decl) == 0)
3974 /* Error message was already done; now avoid a crash. */
3975 x = gen_rtx_MEM (BLKmode, const0_rtx);
3977 /* An initializer is going to decide the size of this array.
3978 Until we know the size, represent its address with a reg. */
3979 x = gen_rtx_MEM (BLKmode, gen_reg_rtx (Pmode));
3981 set_mem_attributes (x, decl, 1);
3982 SET_DECL_RTL (decl, x);
3984 else if (DECL_MODE (decl) != BLKmode
3985 /* If -ffloat-store, don't put explicit float vars
3987 && !(flag_float_store
3988 && TREE_CODE (type) == REAL_TYPE)
3989 && ! TREE_THIS_VOLATILE (decl)
3990 && (DECL_REGISTER (decl) || optimize)
3991 /* if -fcheck-memory-usage, check all variables. */
3992 && ! current_function_check_memory_usage)
3994 /* Automatic variable that can go in a register. */
3995 int unsignedp = TREE_UNSIGNED (type);
3996 enum machine_mode reg_mode
3997 = promote_mode (type, DECL_MODE (decl), &unsignedp, 0);
3999 SET_DECL_RTL (decl, gen_reg_rtx (reg_mode));
4000 mark_user_reg (DECL_RTL (decl));
4002 if (POINTER_TYPE_P (type))
4003 mark_reg_pointer (DECL_RTL (decl),
4004 TYPE_ALIGN (TREE_TYPE (TREE_TYPE (decl))));
4006 maybe_set_unchanging (DECL_RTL (decl), decl);
4008 /* If something wants our address, try to use ADDRESSOF. */
4009 if (TREE_ADDRESSABLE (decl))
4010 put_var_into_stack (decl);
4013 else if (TREE_CODE (DECL_SIZE_UNIT (decl)) == INTEGER_CST
4014 && ! (flag_stack_check && ! STACK_CHECK_BUILTIN
4015 && 0 < compare_tree_int (DECL_SIZE_UNIT (decl),
4016 STACK_CHECK_MAX_VAR_SIZE)))
4018 /* Variable of fixed size that goes on the stack. */
4022 /* If we previously made RTL for this decl, it must be an array
4023 whose size was determined by the initializer.
4024 The old address was a register; set that register now
4025 to the proper address. */
4026 if (DECL_RTL_SET_P (decl))
4028 if (GET_CODE (DECL_RTL (decl)) != MEM
4029 || GET_CODE (XEXP (DECL_RTL (decl), 0)) != REG)
4031 oldaddr = XEXP (DECL_RTL (decl), 0);
4035 assign_temp (TREE_TYPE (decl), 1, 1, 1));
4037 /* Set alignment we actually gave this decl. */
4038 DECL_ALIGN (decl) = (DECL_MODE (decl) == BLKmode ? BIGGEST_ALIGNMENT
4039 : GET_MODE_BITSIZE (DECL_MODE (decl)));
4040 DECL_USER_ALIGN (decl) = 0;
4044 addr = force_operand (XEXP (DECL_RTL (decl), 0), oldaddr);
4045 if (addr != oldaddr)
4046 emit_move_insn (oldaddr, addr);
4050 /* Dynamic-size object: must push space on the stack. */
4052 rtx address, size, x;
4054 /* Record the stack pointer on entry to block, if have
4055 not already done so. */
4056 do_pending_stack_adjust ();
4057 save_stack_pointer ();
4059 /* In function-at-a-time mode, variable_size doesn't expand this,
4061 if (TREE_CODE (type) == ARRAY_TYPE && TYPE_DOMAIN (type))
4062 expand_expr (TYPE_MAX_VALUE (TYPE_DOMAIN (type)),
4063 const0_rtx, VOIDmode, 0);
4065 /* Compute the variable's size, in bytes. */
4066 size = expand_expr (DECL_SIZE_UNIT (decl), NULL_RTX, VOIDmode, 0);
4069 /* Allocate space on the stack for the variable. Note that
4070 DECL_ALIGN says how the variable is to be aligned and we
4071 cannot use it to conclude anything about the alignment of
4073 address = allocate_dynamic_stack_space (size, NULL_RTX,
4074 TYPE_ALIGN (TREE_TYPE (decl)));
4076 /* Reference the variable indirect through that rtx. */
4077 x = gen_rtx_MEM (DECL_MODE (decl), address);
4078 set_mem_attributes (x, decl, 1);
4079 SET_DECL_RTL (decl, x);
4082 /* Indicate the alignment we actually gave this variable. */
4083 #ifdef STACK_BOUNDARY
4084 DECL_ALIGN (decl) = STACK_BOUNDARY;
4086 DECL_ALIGN (decl) = BIGGEST_ALIGNMENT;
4088 DECL_USER_ALIGN (decl) = 0;
4092 /* Emit code to perform the initialization of a declaration DECL. */
4095 expand_decl_init (decl)
4098 int was_used = TREE_USED (decl);
4100 /* If this is a CONST_DECL, we don't have to generate any code, but
4101 if DECL_INITIAL is a constant, call expand_expr to force TREE_CST_RTL
4102 to be set while in the obstack containing the constant. If we don't
4103 do this, we can lose if we have functions nested three deep and the middle
4104 function makes a CONST_DECL whose DECL_INITIAL is a STRING_CST while
4105 the innermost function is the first to expand that STRING_CST. */
4106 if (TREE_CODE (decl) == CONST_DECL)
4108 if (DECL_INITIAL (decl) && TREE_CONSTANT (DECL_INITIAL (decl)))
4109 expand_expr (DECL_INITIAL (decl), NULL_RTX, VOIDmode,
4110 EXPAND_INITIALIZER);
4114 if (TREE_STATIC (decl))
4117 /* Compute and store the initial value now. */
4119 if (DECL_INITIAL (decl) == error_mark_node)
4121 enum tree_code code = TREE_CODE (TREE_TYPE (decl));
4123 if (code == INTEGER_TYPE || code == REAL_TYPE || code == ENUMERAL_TYPE
4124 || code == POINTER_TYPE || code == REFERENCE_TYPE)
4125 expand_assignment (decl, convert (TREE_TYPE (decl), integer_zero_node),
4129 else if (DECL_INITIAL (decl) && TREE_CODE (DECL_INITIAL (decl)) != TREE_LIST)
4131 emit_line_note (DECL_SOURCE_FILE (decl), DECL_SOURCE_LINE (decl));
4132 expand_assignment (decl, DECL_INITIAL (decl), 0, 0);
4136 /* Don't let the initialization count as "using" the variable. */
4137 TREE_USED (decl) = was_used;
4139 /* Free any temporaries we made while initializing the decl. */
4140 preserve_temp_slots (NULL_RTX);
4144 /* CLEANUP is an expression to be executed at exit from this binding contour;
4145 for example, in C++, it might call the destructor for this variable.
4147 We wrap CLEANUP in an UNSAVE_EXPR node, so that we can expand the
4148 CLEANUP multiple times, and have the correct semantics. This
4149 happens in exception handling, for gotos, returns, breaks that
4150 leave the current scope.
4152 If CLEANUP is nonzero and DECL is zero, we record a cleanup
4153 that is not associated with any particular variable. */
4156 expand_decl_cleanup (decl, cleanup)
4159 struct nesting *thisblock;
4161 /* Error if we are not in any block. */
4162 if (cfun == 0 || block_stack == 0)
4165 thisblock = block_stack;
4167 /* Record the cleanup if there is one. */
4173 tree *cleanups = &thisblock->data.block.cleanups;
4174 int cond_context = conditional_context ();
4178 rtx flag = gen_reg_rtx (word_mode);
4183 emit_move_insn (flag, const0_rtx);
4184 set_flag_0 = get_insns ();
4187 thisblock->data.block.last_unconditional_cleanup
4188 = emit_insns_after (set_flag_0,
4189 thisblock->data.block.last_unconditional_cleanup);
4191 emit_move_insn (flag, const1_rtx);
4193 cond = build_decl (VAR_DECL, NULL_TREE, type_for_mode (word_mode, 1));
4194 SET_DECL_RTL (cond, flag);
4196 /* Conditionalize the cleanup. */
4197 cleanup = build (COND_EXPR, void_type_node,
4198 truthvalue_conversion (cond),
4199 cleanup, integer_zero_node);
4200 cleanup = fold (cleanup);
4202 cleanups = thisblock->data.block.cleanup_ptr;
4205 cleanup = unsave_expr (cleanup);
4207 t = *cleanups = tree_cons (decl, cleanup, *cleanups);
4210 /* If this block has a cleanup, it belongs in stack_block_stack. */
4211 stack_block_stack = thisblock;
4218 if (! using_eh_for_cleanups_p)
4219 TREE_ADDRESSABLE (t) = 1;
4221 expand_eh_region_start ();
4228 thisblock->data.block.last_unconditional_cleanup
4229 = emit_insns_after (seq,
4230 thisblock->data.block.last_unconditional_cleanup);
4234 thisblock->data.block.last_unconditional_cleanup
4236 /* When we insert instructions after the last unconditional cleanup,
4237 we don't adjust last_insn. That means that a later add_insn will
4238 clobber the instructions we've just added. The easiest way to
4239 fix this is to just insert another instruction here, so that the
4240 instructions inserted after the last unconditional cleanup are
4241 never the last instruction. */
4242 emit_note (NULL, NOTE_INSN_DELETED);
4243 thisblock->data.block.cleanup_ptr = &thisblock->data.block.cleanups;
4249 /* DECL is an anonymous union. CLEANUP is a cleanup for DECL.
4250 DECL_ELTS is the list of elements that belong to DECL's type.
4251 In each, the TREE_VALUE is a VAR_DECL, and the TREE_PURPOSE a cleanup. */
4254 expand_anon_union_decl (decl, cleanup, decl_elts)
4255 tree decl, cleanup, decl_elts;
4257 struct nesting *thisblock = cfun == 0 ? 0 : block_stack;
4261 /* If any of the elements are addressable, so is the entire union. */
4262 for (t = decl_elts; t; t = TREE_CHAIN (t))
4263 if (TREE_ADDRESSABLE (TREE_VALUE (t)))
4265 TREE_ADDRESSABLE (decl) = 1;
4270 expand_decl_cleanup (decl, cleanup);
4271 x = DECL_RTL (decl);
4273 /* Go through the elements, assigning RTL to each. */
4274 for (t = decl_elts; t; t = TREE_CHAIN (t))
4276 tree decl_elt = TREE_VALUE (t);
4277 tree cleanup_elt = TREE_PURPOSE (t);
4278 enum machine_mode mode = TYPE_MODE (TREE_TYPE (decl_elt));
4280 /* Propagate the union's alignment to the elements. */
4281 DECL_ALIGN (decl_elt) = DECL_ALIGN (decl);
4282 DECL_USER_ALIGN (decl_elt) = DECL_USER_ALIGN (decl);
4284 /* If the element has BLKmode and the union doesn't, the union is
4285 aligned such that the element doesn't need to have BLKmode, so
4286 change the element's mode to the appropriate one for its size. */
4287 if (mode == BLKmode && DECL_MODE (decl) != BLKmode)
4288 DECL_MODE (decl_elt) = mode
4289 = mode_for_size_tree (DECL_SIZE (decl_elt), MODE_INT, 1);
4291 /* (SUBREG (MEM ...)) at RTL generation time is invalid, so we
4292 instead create a new MEM rtx with the proper mode. */
4293 if (GET_CODE (x) == MEM)
4295 if (mode == GET_MODE (x))
4296 SET_DECL_RTL (decl_elt, x);
4298 SET_DECL_RTL (decl_elt, adjust_address_nv (x, mode, 0));
4300 else if (GET_CODE (x) == REG)
4302 if (mode == GET_MODE (x))
4303 SET_DECL_RTL (decl_elt, x);
4305 SET_DECL_RTL (decl_elt, gen_lowpart_SUBREG (mode, x));
4310 /* Record the cleanup if there is one. */
4313 thisblock->data.block.cleanups
4314 = tree_cons (decl_elt, cleanup_elt,
4315 thisblock->data.block.cleanups);
4319 /* Expand a list of cleanups LIST.
4320 Elements may be expressions or may be nested lists.
4322 If DONT_DO is nonnull, then any list-element
4323 whose TREE_PURPOSE matches DONT_DO is omitted.
4324 This is sometimes used to avoid a cleanup associated with
4325 a value that is being returned out of the scope.
4327 If IN_FIXUP is non-zero, we are generating this cleanup for a fixup
4328 goto and handle protection regions specially in that case.
4330 If REACHABLE, we emit code, otherwise just inform the exception handling
4331 code about this finalization. */
4334 expand_cleanups (list, dont_do, in_fixup, reachable)
4341 for (tail = list; tail; tail = TREE_CHAIN (tail))
4342 if (dont_do == 0 || TREE_PURPOSE (tail) != dont_do)
4344 if (TREE_CODE (TREE_VALUE (tail)) == TREE_LIST)
4345 expand_cleanups (TREE_VALUE (tail), dont_do, in_fixup, reachable);
4348 if (! in_fixup && using_eh_for_cleanups_p)
4349 expand_eh_region_end_cleanup (TREE_VALUE (tail));
4353 /* Cleanups may be run multiple times. For example,
4354 when exiting a binding contour, we expand the
4355 cleanups associated with that contour. When a goto
4356 within that binding contour has a target outside that
4357 contour, it will expand all cleanups from its scope to
4358 the target. Though the cleanups are expanded multiple
4359 times, the control paths are non-overlapping so the
4360 cleanups will not be executed twice. */
4362 /* We may need to protect from outer cleanups. */
4363 if (in_fixup && using_eh_for_cleanups_p)
4365 expand_eh_region_start ();
4367 expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0);
4369 expand_eh_region_end_fixup (TREE_VALUE (tail));
4372 expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0);
4380 /* Mark when the context we are emitting RTL for as a conditional
4381 context, so that any cleanup actions we register with
4382 expand_decl_init will be properly conditionalized when those
4383 cleanup actions are later performed. Must be called before any
4384 expression (tree) is expanded that is within a conditional context. */
4387 start_cleanup_deferral ()
4389 /* block_stack can be NULL if we are inside the parameter list. It is
4390 OK to do nothing, because cleanups aren't possible here. */
4392 ++block_stack->data.block.conditional_code;
4395 /* Mark the end of a conditional region of code. Because cleanup
4396 deferrals may be nested, we may still be in a conditional region
4397 after we end the currently deferred cleanups, only after we end all
4398 deferred cleanups, are we back in unconditional code. */
4401 end_cleanup_deferral ()
4403 /* block_stack can be NULL if we are inside the parameter list. It is
4404 OK to do nothing, because cleanups aren't possible here. */
4406 --block_stack->data.block.conditional_code;
4409 /* Move all cleanups from the current block_stack
4410 to the containing block_stack, where they are assumed to
4411 have been created. If anything can cause a temporary to
4412 be created, but not expanded for more than one level of
4413 block_stacks, then this code will have to change. */
4418 struct nesting *block = block_stack;
4419 struct nesting *outer = block->next;
4421 outer->data.block.cleanups
4422 = chainon (block->data.block.cleanups,
4423 outer->data.block.cleanups);
4424 block->data.block.cleanups = 0;
4428 last_cleanup_this_contour ()
4430 if (block_stack == 0)
4433 return block_stack->data.block.cleanups;
4436 /* Return 1 if there are any pending cleanups at this point.
4437 If THIS_CONTOUR is nonzero, check the current contour as well.
4438 Otherwise, look only at the contours that enclose this one. */
4441 any_pending_cleanups (this_contour)
4444 struct nesting *block;
4446 if (cfun == NULL || cfun->stmt == NULL || block_stack == 0)
4449 if (this_contour && block_stack->data.block.cleanups != NULL)
4451 if (block_stack->data.block.cleanups == 0
4452 && block_stack->data.block.outer_cleanups == 0)
4455 for (block = block_stack->next; block; block = block->next)
4456 if (block->data.block.cleanups != 0)
4462 /* Enter a case (Pascal) or switch (C) statement.
4463 Push a block onto case_stack and nesting_stack
4464 to accumulate the case-labels that are seen
4465 and to record the labels generated for the statement.
4467 EXIT_FLAG is nonzero if `exit_something' should exit this case stmt.
4468 Otherwise, this construct is transparent for `exit_something'.
4470 EXPR is the index-expression to be dispatched on.
4471 TYPE is its nominal type. We could simply convert EXPR to this type,
4472 but instead we take short cuts. */
4475 expand_start_case (exit_flag, expr, type, printname)
4479 const char *printname;
4481 struct nesting *thiscase = ALLOC_NESTING ();
4483 /* Make an entry on case_stack for the case we are entering. */
4485 thiscase->next = case_stack;
4486 thiscase->all = nesting_stack;
4487 thiscase->depth = ++nesting_depth;
4488 thiscase->exit_label = exit_flag ? gen_label_rtx () : 0;
4489 thiscase->data.case_stmt.case_list = 0;
4490 thiscase->data.case_stmt.index_expr = expr;
4491 thiscase->data.case_stmt.nominal_type = type;
4492 thiscase->data.case_stmt.default_label = 0;
4493 thiscase->data.case_stmt.printname = printname;
4494 thiscase->data.case_stmt.line_number_status = force_line_numbers ();
4495 case_stack = thiscase;
4496 nesting_stack = thiscase;
4498 do_pending_stack_adjust ();
4500 /* Make sure case_stmt.start points to something that won't
4501 need any transformation before expand_end_case. */
4502 if (GET_CODE (get_last_insn ()) != NOTE)
4503 emit_note (NULL, NOTE_INSN_DELETED);
4505 thiscase->data.case_stmt.start = get_last_insn ();
4507 start_cleanup_deferral ();
4510 /* Start a "dummy case statement" within which case labels are invalid
4511 and are not connected to any larger real case statement.
4512 This can be used if you don't want to let a case statement jump
4513 into the middle of certain kinds of constructs. */
4516 expand_start_case_dummy ()
4518 struct nesting *thiscase = ALLOC_NESTING ();
4520 /* Make an entry on case_stack for the dummy. */
4522 thiscase->next = case_stack;
4523 thiscase->all = nesting_stack;
4524 thiscase->depth = ++nesting_depth;
4525 thiscase->exit_label = 0;
4526 thiscase->data.case_stmt.case_list = 0;
4527 thiscase->data.case_stmt.start = 0;
4528 thiscase->data.case_stmt.nominal_type = 0;
4529 thiscase->data.case_stmt.default_label = 0;
4530 case_stack = thiscase;
4531 nesting_stack = thiscase;
4532 start_cleanup_deferral ();
4535 /* End a dummy case statement. */
4538 expand_end_case_dummy ()
4540 end_cleanup_deferral ();
4541 POPSTACK (case_stack);
4544 /* Return the data type of the index-expression
4545 of the innermost case statement, or null if none. */
4548 case_index_expr_type ()
4551 return TREE_TYPE (case_stack->data.case_stmt.index_expr);
4558 /* If this is the first label, warn if any insns have been emitted. */
4559 if (case_stack->data.case_stmt.line_number_status >= 0)
4563 restore_line_number_status
4564 (case_stack->data.case_stmt.line_number_status);
4565 case_stack->data.case_stmt.line_number_status = -1;
4567 for (insn = case_stack->data.case_stmt.start;
4569 insn = NEXT_INSN (insn))
4571 if (GET_CODE (insn) == CODE_LABEL)
4573 if (GET_CODE (insn) != NOTE
4574 && (GET_CODE (insn) != INSN || GET_CODE (PATTERN (insn)) != USE))
4577 insn = PREV_INSN (insn);
4578 while (insn && (GET_CODE (insn) != NOTE || NOTE_LINE_NUMBER (insn) < 0));
4580 /* If insn is zero, then there must have been a syntax error. */
4582 warning_with_file_and_line (NOTE_SOURCE_FILE (insn),
4583 NOTE_LINE_NUMBER (insn),
4584 "unreachable code at beginning of %s",
4585 case_stack->data.case_stmt.printname);
4592 /* Accumulate one case or default label inside a case or switch statement.
4593 VALUE is the value of the case (a null pointer, for a default label).
4594 The function CONVERTER, when applied to arguments T and V,
4595 converts the value V to the type T.
4597 If not currently inside a case or switch statement, return 1 and do
4598 nothing. The caller will print a language-specific error message.
4599 If VALUE is a duplicate or overlaps, return 2 and do nothing
4600 except store the (first) duplicate node in *DUPLICATE.
4601 If VALUE is out of range, return 3 and do nothing.
4602 If we are jumping into the scope of a cleanup or var-sized array, return 5.
4603 Return 0 on success.
4605 Extended to handle range statements. */
4608 pushcase (value, converter, label, duplicate)
4610 tree (*converter) PARAMS ((tree, tree));
4617 /* Fail if not inside a real case statement. */
4618 if (! (case_stack && case_stack->data.case_stmt.start))
4621 if (stack_block_stack
4622 && stack_block_stack->depth > case_stack->depth)
4625 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
4626 nominal_type = case_stack->data.case_stmt.nominal_type;
4628 /* If the index is erroneous, avoid more problems: pretend to succeed. */
4629 if (index_type == error_mark_node)
4632 /* Convert VALUE to the type in which the comparisons are nominally done. */
4634 value = (*converter) (nominal_type, value);
4638 /* Fail if this value is out of range for the actual type of the index
4639 (which may be narrower than NOMINAL_TYPE). */
4641 && (TREE_CONSTANT_OVERFLOW (value)
4642 || ! int_fits_type_p (value, index_type)))
4645 return add_case_node (value, value, label, duplicate);
4648 /* Like pushcase but this case applies to all values between VALUE1 and
4649 VALUE2 (inclusive). If VALUE1 is NULL, the range starts at the lowest
4650 value of the index type and ends at VALUE2. If VALUE2 is NULL, the range
4651 starts at VALUE1 and ends at the highest value of the index type.
4652 If both are NULL, this case applies to all values.
4654 The return value is the same as that of pushcase but there is one
4655 additional error code: 4 means the specified range was empty. */
4658 pushcase_range (value1, value2, converter, label, duplicate)
4659 tree value1, value2;
4660 tree (*converter) PARAMS ((tree, tree));
4667 /* Fail if not inside a real case statement. */
4668 if (! (case_stack && case_stack->data.case_stmt.start))
4671 if (stack_block_stack
4672 && stack_block_stack->depth > case_stack->depth)
4675 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
4676 nominal_type = case_stack->data.case_stmt.nominal_type;
4678 /* If the index is erroneous, avoid more problems: pretend to succeed. */
4679 if (index_type == error_mark_node)
4684 /* Convert VALUEs to type in which the comparisons are nominally done
4685 and replace any unspecified value with the corresponding bound. */
4687 value1 = TYPE_MIN_VALUE (index_type);
4689 value2 = TYPE_MAX_VALUE (index_type);
4691 /* Fail if the range is empty. Do this before any conversion since
4692 we want to allow out-of-range empty ranges. */
4693 if (value2 != 0 && tree_int_cst_lt (value2, value1))
4696 /* If the max was unbounded, use the max of the nominal_type we are
4697 converting to. Do this after the < check above to suppress false
4700 value2 = TYPE_MAX_VALUE (nominal_type);
4702 value1 = (*converter) (nominal_type, value1);
4703 value2 = (*converter) (nominal_type, value2);
4705 /* Fail if these values are out of range. */
4706 if (TREE_CONSTANT_OVERFLOW (value1)
4707 || ! int_fits_type_p (value1, index_type))
4710 if (TREE_CONSTANT_OVERFLOW (value2)
4711 || ! int_fits_type_p (value2, index_type))
4714 return add_case_node (value1, value2, label, duplicate);
4717 /* Do the actual insertion of a case label for pushcase and pushcase_range
4718 into case_stack->data.case_stmt.case_list. Use an AVL tree to avoid
4719 slowdown for large switch statements. */
4722 add_case_node (low, high, label, duplicate)
4727 struct case_node *p, **q, *r;
4729 /* If there's no HIGH value, then this is not a case range; it's
4730 just a simple case label. But that's just a degenerate case
4735 /* Handle default labels specially. */
4738 if (case_stack->data.case_stmt.default_label != 0)
4740 *duplicate = case_stack->data.case_stmt.default_label;
4743 case_stack->data.case_stmt.default_label = label;
4744 expand_label (label);
4748 q = &case_stack->data.case_stmt.case_list;
4755 /* Keep going past elements distinctly greater than HIGH. */
4756 if (tree_int_cst_lt (high, p->low))
4759 /* or distinctly less than LOW. */
4760 else if (tree_int_cst_lt (p->high, low))
4765 /* We have an overlap; this is an error. */
4766 *duplicate = p->code_label;
4771 /* Add this label to the chain, and succeed. */
4773 r = (struct case_node *) xmalloc (sizeof (struct case_node));
4776 /* If the bounds are equal, turn this into the one-value case. */
4777 if (tree_int_cst_equal (low, high))
4782 r->code_label = label;
4783 expand_label (label);
4793 struct case_node *s;
4799 if (! (b = p->balance))
4800 /* Growth propagation from left side. */
4807 if ((p->left = s = r->right))
4816 if ((r->parent = s))
4824 case_stack->data.case_stmt.case_list = r;
4827 /* r->balance == +1 */
4832 struct case_node *t = r->right;
4834 if ((p->left = s = t->right))
4838 if ((r->right = s = t->left))
4852 if ((t->parent = s))
4860 case_stack->data.case_stmt.case_list = t;
4867 /* p->balance == +1; growth of left side balances the node. */
4877 if (! (b = p->balance))
4878 /* Growth propagation from right side. */
4886 if ((p->right = s = r->left))
4894 if ((r->parent = s))
4903 case_stack->data.case_stmt.case_list = r;
4907 /* r->balance == -1 */
4911 struct case_node *t = r->left;
4913 if ((p->right = s = t->left))
4918 if ((r->left = s = t->right))
4932 if ((t->parent = s))
4941 case_stack->data.case_stmt.case_list = t;
4947 /* p->balance == -1; growth of right side balances the node. */
4960 /* Returns the number of possible values of TYPE.
4961 Returns -1 if the number is unknown, variable, or if the number does not
4962 fit in a HOST_WIDE_INT.
4963 Sets *SPARENESS to 2 if TYPE is an ENUMERAL_TYPE whose values
4964 do not increase monotonically (there may be duplicates);
4965 to 1 if the values increase monotonically, but not always by 1;
4966 otherwise sets it to 0. */
4969 all_cases_count (type, spareness)
4974 HOST_WIDE_INT count, minval, lastval;
4978 switch (TREE_CODE (type))
4985 count = 1 << BITS_PER_UNIT;
4990 if (TYPE_MAX_VALUE (type) != 0
4991 && 0 != (t = fold (build (MINUS_EXPR, type, TYPE_MAX_VALUE (type),
4992 TYPE_MIN_VALUE (type))))
4993 && 0 != (t = fold (build (PLUS_EXPR, type, t,
4994 convert (type, integer_zero_node))))
4995 && host_integerp (t, 1))
4996 count = tree_low_cst (t, 1);
5002 /* Don't waste time with enumeral types with huge values. */
5003 if (! host_integerp (TYPE_MIN_VALUE (type), 0)
5004 || TYPE_MAX_VALUE (type) == 0
5005 || ! host_integerp (TYPE_MAX_VALUE (type), 0))
5008 lastval = minval = tree_low_cst (TYPE_MIN_VALUE (type), 0);
5011 for (t = TYPE_VALUES (type); t != NULL_TREE; t = TREE_CHAIN (t))
5013 HOST_WIDE_INT thisval = tree_low_cst (TREE_VALUE (t), 0);
5015 if (*spareness == 2 || thisval < lastval)
5017 else if (thisval != minval + count)
5027 #define BITARRAY_TEST(ARRAY, INDEX) \
5028 ((ARRAY)[(unsigned) (INDEX) / HOST_BITS_PER_CHAR]\
5029 & (1 << ((unsigned) (INDEX) % HOST_BITS_PER_CHAR)))
5030 #define BITARRAY_SET(ARRAY, INDEX) \
5031 ((ARRAY)[(unsigned) (INDEX) / HOST_BITS_PER_CHAR]\
5032 |= 1 << ((unsigned) (INDEX) % HOST_BITS_PER_CHAR))
5034 /* Set the elements of the bitstring CASES_SEEN (which has length COUNT),
5035 with the case values we have seen, assuming the case expression
5037 SPARSENESS is as determined by all_cases_count.
5039 The time needed is proportional to COUNT, unless
5040 SPARSENESS is 2, in which case quadratic time is needed. */
5043 mark_seen_cases (type, cases_seen, count, sparseness)
5045 unsigned char *cases_seen;
5046 HOST_WIDE_INT count;
5049 tree next_node_to_try = NULL_TREE;
5050 HOST_WIDE_INT next_node_offset = 0;
5052 struct case_node *n, *root = case_stack->data.case_stmt.case_list;
5053 tree val = make_node (INTEGER_CST);
5055 TREE_TYPE (val) = type;
5059 else if (sparseness == 2)
5062 unsigned HOST_WIDE_INT xlo;
5064 /* This less efficient loop is only needed to handle
5065 duplicate case values (multiple enum constants
5066 with the same value). */
5067 TREE_TYPE (val) = TREE_TYPE (root->low);
5068 for (t = TYPE_VALUES (type), xlo = 0; t != NULL_TREE;
5069 t = TREE_CHAIN (t), xlo++)
5071 TREE_INT_CST_LOW (val) = TREE_INT_CST_LOW (TREE_VALUE (t));
5072 TREE_INT_CST_HIGH (val) = TREE_INT_CST_HIGH (TREE_VALUE (t));
5076 /* Keep going past elements distinctly greater than VAL. */
5077 if (tree_int_cst_lt (val, n->low))
5080 /* or distinctly less than VAL. */
5081 else if (tree_int_cst_lt (n->high, val))
5086 /* We have found a matching range. */
5087 BITARRAY_SET (cases_seen, xlo);
5097 case_stack->data.case_stmt.case_list = root = case_tree2list (root, 0);
5099 for (n = root; n; n = n->right)
5101 TREE_INT_CST_LOW (val) = TREE_INT_CST_LOW (n->low);
5102 TREE_INT_CST_HIGH (val) = TREE_INT_CST_HIGH (n->low);
5103 while (! tree_int_cst_lt (n->high, val))
5105 /* Calculate (into xlo) the "offset" of the integer (val).
5106 The element with lowest value has offset 0, the next smallest
5107 element has offset 1, etc. */
5109 unsigned HOST_WIDE_INT xlo;
5113 if (sparseness && TYPE_VALUES (type) != NULL_TREE)
5115 /* The TYPE_VALUES will be in increasing order, so
5116 starting searching where we last ended. */
5117 t = next_node_to_try;
5118 xlo = next_node_offset;
5124 t = TYPE_VALUES (type);
5127 if (tree_int_cst_equal (val, TREE_VALUE (t)))
5129 next_node_to_try = TREE_CHAIN (t);
5130 next_node_offset = xlo + 1;
5135 if (t == next_node_to_try)
5144 t = TYPE_MIN_VALUE (type);
5146 neg_double (TREE_INT_CST_LOW (t), TREE_INT_CST_HIGH (t),
5150 add_double (xlo, xhi,
5151 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val),
5155 if (xhi == 0 && xlo < (unsigned HOST_WIDE_INT) count)
5156 BITARRAY_SET (cases_seen, xlo);
5158 add_double (TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val),
5160 &TREE_INT_CST_LOW (val), &TREE_INT_CST_HIGH (val));
5166 /* Called when the index of a switch statement is an enumerated type
5167 and there is no default label.
5169 Checks that all enumeration literals are covered by the case
5170 expressions of a switch. Also, warn if there are any extra
5171 switch cases that are *not* elements of the enumerated type.
5173 If all enumeration literals were covered by the case expressions,
5174 turn one of the expressions into the default expression since it should
5175 not be possible to fall through such a switch. */
5178 check_for_full_enumeration_handling (type)
5181 struct case_node *n;
5184 /* True iff the selector type is a numbered set mode. */
5187 /* The number of possible selector values. */
5190 /* For each possible selector value. a one iff it has been matched
5191 by a case value alternative. */
5192 unsigned char *cases_seen;
5194 /* The allocated size of cases_seen, in chars. */
5195 HOST_WIDE_INT bytes_needed;
5200 size = all_cases_count (type, &sparseness);
5201 bytes_needed = (size + HOST_BITS_PER_CHAR) / HOST_BITS_PER_CHAR;
5203 if (size > 0 && size < 600000
5204 /* We deliberately use calloc here, not cmalloc, so that we can suppress
5205 this optimization if we don't have enough memory rather than
5206 aborting, as xmalloc would do. */
5208 (unsigned char *) really_call_calloc (bytes_needed, 1)) != NULL)
5211 tree v = TYPE_VALUES (type);
5213 /* The time complexity of this code is normally O(N), where
5214 N being the number of members in the enumerated type.
5215 However, if type is a ENUMERAL_TYPE whose values do not
5216 increase monotonically, O(N*log(N)) time may be needed. */
5218 mark_seen_cases (type, cases_seen, size, sparseness);
5220 for (i = 0; v != NULL_TREE && i < size; i++, v = TREE_CHAIN (v))
5221 if (BITARRAY_TEST (cases_seen, i) == 0)
5222 warning ("enumeration value `%s' not handled in switch",
5223 IDENTIFIER_POINTER (TREE_PURPOSE (v)));
5228 /* Now we go the other way around; we warn if there are case
5229 expressions that don't correspond to enumerators. This can
5230 occur since C and C++ don't enforce type-checking of
5231 assignments to enumeration variables. */
5233 if (case_stack->data.case_stmt.case_list
5234 && case_stack->data.case_stmt.case_list->left)
5235 case_stack->data.case_stmt.case_list
5236 = case_tree2list (case_stack->data.case_stmt.case_list, 0);
5238 for (n = case_stack->data.case_stmt.case_list; n; n = n->right)
5240 for (chain = TYPE_VALUES (type);
5241 chain && !tree_int_cst_equal (n->low, TREE_VALUE (chain));
5242 chain = TREE_CHAIN (chain))
5247 if (TYPE_NAME (type) == 0)
5248 warning ("case value `%ld' not in enumerated type",
5249 (long) TREE_INT_CST_LOW (n->low));
5251 warning ("case value `%ld' not in enumerated type `%s'",
5252 (long) TREE_INT_CST_LOW (n->low),
5253 IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
5256 : DECL_NAME (TYPE_NAME (type))));
5258 if (!tree_int_cst_equal (n->low, n->high))
5260 for (chain = TYPE_VALUES (type);
5261 chain && !tree_int_cst_equal (n->high, TREE_VALUE (chain));
5262 chain = TREE_CHAIN (chain))
5267 if (TYPE_NAME (type) == 0)
5268 warning ("case value `%ld' not in enumerated type",
5269 (long) TREE_INT_CST_LOW (n->high));
5271 warning ("case value `%ld' not in enumerated type `%s'",
5272 (long) TREE_INT_CST_LOW (n->high),
5273 IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
5276 : DECL_NAME (TYPE_NAME (type))));
5282 /* Free CN, and its children. */
5285 free_case_nodes (cn)
5290 free_case_nodes (cn->left);
5291 free_case_nodes (cn->right);
5298 /* Terminate a case (Pascal) or switch (C) statement
5299 in which ORIG_INDEX is the expression to be tested.
5300 Generate the code to test it and jump to the right place. */
5303 expand_end_case (orig_index)
5306 tree minval = NULL_TREE, maxval = NULL_TREE, range = NULL_TREE, orig_minval;
5307 rtx default_label = 0;
5308 struct case_node *n;
5315 rtx before_case, end;
5316 struct nesting *thiscase = case_stack;
5317 tree index_expr, index_type;
5320 /* Don't crash due to previous errors. */
5321 if (thiscase == NULL)
5324 table_label = gen_label_rtx ();
5325 index_expr = thiscase->data.case_stmt.index_expr;
5326 index_type = TREE_TYPE (index_expr);
5327 unsignedp = TREE_UNSIGNED (index_type);
5329 do_pending_stack_adjust ();
5331 /* This might get an spurious warning in the presence of a syntax error;
5332 it could be fixed by moving the call to check_seenlabel after the
5333 check for error_mark_node, and copying the code of check_seenlabel that
5334 deals with case_stack->data.case_stmt.line_number_status /
5335 restore_line_number_status in front of the call to end_cleanup_deferral;
5336 However, this might miss some useful warnings in the presence of
5337 non-syntax errors. */
5340 /* An ERROR_MARK occurs for various reasons including invalid data type. */
5341 if (index_type != error_mark_node)
5343 /* If switch expression was an enumerated type, check that all
5344 enumeration literals are covered by the cases.
5345 No sense trying this if there's a default case, however. */
5347 if (!thiscase->data.case_stmt.default_label
5348 && TREE_CODE (TREE_TYPE (orig_index)) == ENUMERAL_TYPE
5349 && TREE_CODE (index_expr) != INTEGER_CST)
5350 check_for_full_enumeration_handling (TREE_TYPE (orig_index));
5352 /* If we don't have a default-label, create one here,
5353 after the body of the switch. */
5354 if (thiscase->data.case_stmt.default_label == 0)
5356 thiscase->data.case_stmt.default_label
5357 = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
5358 expand_label (thiscase->data.case_stmt.default_label);
5360 default_label = label_rtx (thiscase->data.case_stmt.default_label);
5362 before_case = get_last_insn ();
5364 if (thiscase->data.case_stmt.case_list
5365 && thiscase->data.case_stmt.case_list->left)
5366 thiscase->data.case_stmt.case_list
5367 = case_tree2list (thiscase->data.case_stmt.case_list, 0);
5369 /* Simplify the case-list before we count it. */
5370 group_case_nodes (thiscase->data.case_stmt.case_list);
5372 /* Get upper and lower bounds of case values.
5373 Also convert all the case values to the index expr's data type. */
5376 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5378 /* Check low and high label values are integers. */
5379 if (TREE_CODE (n->low) != INTEGER_CST)
5381 if (TREE_CODE (n->high) != INTEGER_CST)
5384 n->low = convert (index_type, n->low);
5385 n->high = convert (index_type, n->high);
5387 /* Count the elements and track the largest and smallest
5388 of them (treating them as signed even if they are not). */
5396 if (INT_CST_LT (n->low, minval))
5398 if (INT_CST_LT (maxval, n->high))
5401 /* A range counts double, since it requires two compares. */
5402 if (! tree_int_cst_equal (n->low, n->high))
5406 orig_minval = minval;
5408 /* Compute span of values. */
5410 range = fold (build (MINUS_EXPR, index_type, maxval, minval));
5412 end_cleanup_deferral ();
5416 expand_expr (index_expr, const0_rtx, VOIDmode, 0);
5418 emit_jump (default_label);
5421 /* If range of values is much bigger than number of values,
5422 make a sequence of conditional branches instead of a dispatch.
5423 If the switch-index is a constant, do it this way
5424 because we can optimize it. */
5426 else if (count < case_values_threshold ()
5427 || compare_tree_int (range, 10 * count) > 0
5428 /* RANGE may be signed, and really large ranges will show up
5429 as negative numbers. */
5430 || compare_tree_int (range, 0) < 0
5431 #ifndef ASM_OUTPUT_ADDR_DIFF_ELT
5434 || TREE_CODE (index_expr) == INTEGER_CST
5435 || (TREE_CODE (index_expr) == COMPOUND_EXPR
5436 && TREE_CODE (TREE_OPERAND (index_expr, 1)) == INTEGER_CST))
5438 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
5440 /* If the index is a short or char that we do not have
5441 an insn to handle comparisons directly, convert it to
5442 a full integer now, rather than letting each comparison
5443 generate the conversion. */
5445 if (GET_MODE_CLASS (GET_MODE (index)) == MODE_INT
5446 && ! have_insn_for (COMPARE, GET_MODE (index)))
5448 enum machine_mode wider_mode;
5449 for (wider_mode = GET_MODE (index); wider_mode != VOIDmode;
5450 wider_mode = GET_MODE_WIDER_MODE (wider_mode))
5451 if (have_insn_for (COMPARE, wider_mode))
5453 index = convert_to_mode (wider_mode, index, unsignedp);
5459 do_pending_stack_adjust ();
5461 index = protect_from_queue (index, 0);
5462 if (GET_CODE (index) == MEM)
5463 index = copy_to_reg (index);
5464 if (GET_CODE (index) == CONST_INT
5465 || TREE_CODE (index_expr) == INTEGER_CST)
5467 /* Make a tree node with the proper constant value
5468 if we don't already have one. */
5469 if (TREE_CODE (index_expr) != INTEGER_CST)
5472 = build_int_2 (INTVAL (index),
5473 unsignedp || INTVAL (index) >= 0 ? 0 : -1);
5474 index_expr = convert (index_type, index_expr);
5477 /* For constant index expressions we need only
5478 issue an unconditional branch to the appropriate
5479 target code. The job of removing any unreachable
5480 code is left to the optimisation phase if the
5481 "-O" option is specified. */
5482 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5483 if (! tree_int_cst_lt (index_expr, n->low)
5484 && ! tree_int_cst_lt (n->high, index_expr))
5488 emit_jump (label_rtx (n->code_label));
5490 emit_jump (default_label);
5494 /* If the index expression is not constant we generate
5495 a binary decision tree to select the appropriate
5496 target code. This is done as follows:
5498 The list of cases is rearranged into a binary tree,
5499 nearly optimal assuming equal probability for each case.
5501 The tree is transformed into RTL, eliminating
5502 redundant test conditions at the same time.
5504 If program flow could reach the end of the
5505 decision tree an unconditional jump to the
5506 default code is emitted. */
5509 = (TREE_CODE (TREE_TYPE (orig_index)) != ENUMERAL_TYPE
5510 && estimate_case_costs (thiscase->data.case_stmt.case_list));
5511 balance_case_nodes (&thiscase->data.case_stmt.case_list, NULL);
5512 emit_case_nodes (index, thiscase->data.case_stmt.case_list,
5513 default_label, index_type);
5514 emit_jump_if_reachable (default_label);
5519 if (! try_casesi (index_type, index_expr, minval, range,
5520 table_label, default_label))
5522 index_type = thiscase->data.case_stmt.nominal_type;
5523 if (! try_tablejump (index_type, index_expr, minval, range,
5524 table_label, default_label))
5528 /* Get table of labels to jump to, in order of case index. */
5530 ncases = TREE_INT_CST_LOW (range) + 1;
5531 labelvec = (rtx *) alloca (ncases * sizeof (rtx));
5532 memset ((char *) labelvec, 0, ncases * sizeof (rtx));
5534 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5537 = TREE_INT_CST_LOW (n->low) - TREE_INT_CST_LOW (orig_minval);
5542 = gen_rtx_LABEL_REF (Pmode, label_rtx (n->code_label));
5543 if (i + TREE_INT_CST_LOW (orig_minval)
5544 == TREE_INT_CST_LOW (n->high))
5550 /* Fill in the gaps with the default. */
5551 for (i = 0; i < ncases; i++)
5552 if (labelvec[i] == 0)
5553 labelvec[i] = gen_rtx_LABEL_REF (Pmode, default_label);
5555 /* Output the table */
5556 emit_label (table_label);
5558 if (CASE_VECTOR_PC_RELATIVE || flag_pic)
5559 emit_jump_insn (gen_rtx_ADDR_DIFF_VEC (CASE_VECTOR_MODE,
5560 gen_rtx_LABEL_REF (Pmode, table_label),
5561 gen_rtvec_v (ncases, labelvec),
5562 const0_rtx, const0_rtx));
5564 emit_jump_insn (gen_rtx_ADDR_VEC (CASE_VECTOR_MODE,
5565 gen_rtvec_v (ncases, labelvec)));
5567 /* If the case insn drops through the table,
5568 after the table we must jump to the default-label.
5569 Otherwise record no drop-through after the table. */
5570 #ifdef CASE_DROPS_THROUGH
5571 emit_jump (default_label);
5577 before_case = NEXT_INSN (before_case);
5578 end = get_last_insn ();
5579 squeeze_notes (&before_case, &end);
5580 reorder_insns (before_case, end,
5581 thiscase->data.case_stmt.start);
5584 end_cleanup_deferral ();
5586 if (thiscase->exit_label)
5587 emit_label (thiscase->exit_label);
5589 free_case_nodes (case_stack->data.case_stmt.case_list);
5590 POPSTACK (case_stack);
5595 /* Convert the tree NODE into a list linked by the right field, with the left
5596 field zeroed. RIGHT is used for recursion; it is a list to be placed
5597 rightmost in the resulting list. */
5599 static struct case_node *
5600 case_tree2list (node, right)
5601 struct case_node *node, *right;
5603 struct case_node *left;
5606 right = case_tree2list (node->right, right);
5608 node->right = right;
5609 if ((left = node->left))
5612 return case_tree2list (left, node);
5618 /* Generate code to jump to LABEL if OP1 and OP2 are equal. */
5621 do_jump_if_equal (op1, op2, label, unsignedp)
5622 rtx op1, op2, label;
5625 if (GET_CODE (op1) == CONST_INT
5626 && GET_CODE (op2) == CONST_INT)
5628 if (INTVAL (op1) == INTVAL (op2))
5633 enum machine_mode mode = GET_MODE (op1);
5634 if (mode == VOIDmode)
5635 mode = GET_MODE (op2);
5636 emit_cmp_and_jump_insns (op1, op2, EQ, NULL_RTX, mode, unsignedp,
5641 /* Not all case values are encountered equally. This function
5642 uses a heuristic to weight case labels, in cases where that
5643 looks like a reasonable thing to do.
5645 Right now, all we try to guess is text, and we establish the
5648 chars above space: 16
5657 If we find any cases in the switch that are not either -1 or in the range
5658 of valid ASCII characters, or are control characters other than those
5659 commonly used with "\", don't treat this switch scanning text.
5661 Return 1 if these nodes are suitable for cost estimation, otherwise
5665 estimate_case_costs (node)
5668 tree min_ascii = integer_minus_one_node;
5669 tree max_ascii = convert (TREE_TYPE (node->high), build_int_2 (127, 0));
5673 /* If we haven't already made the cost table, make it now. Note that the
5674 lower bound of the table is -1, not zero. */
5676 if (! cost_table_initialized)
5678 cost_table_initialized = 1;
5680 for (i = 0; i < 128; i++)
5683 COST_TABLE (i) = 16;
5684 else if (ISPUNCT (i))
5686 else if (ISCNTRL (i))
5687 COST_TABLE (i) = -1;
5690 COST_TABLE (' ') = 8;
5691 COST_TABLE ('\t') = 4;
5692 COST_TABLE ('\0') = 4;
5693 COST_TABLE ('\n') = 2;
5694 COST_TABLE ('\f') = 1;
5695 COST_TABLE ('\v') = 1;
5696 COST_TABLE ('\b') = 1;
5699 /* See if all the case expressions look like text. It is text if the
5700 constant is >= -1 and the highest constant is <= 127. Do all comparisons
5701 as signed arithmetic since we don't want to ever access cost_table with a
5702 value less than -1. Also check that none of the constants in a range
5703 are strange control characters. */
5705 for (n = node; n; n = n->right)
5707 if ((INT_CST_LT (n->low, min_ascii)) || INT_CST_LT (max_ascii, n->high))
5710 for (i = (HOST_WIDE_INT) TREE_INT_CST_LOW (n->low);
5711 i <= (HOST_WIDE_INT) TREE_INT_CST_LOW (n->high); i++)
5712 if (COST_TABLE (i) < 0)
5716 /* All interesting values are within the range of interesting
5717 ASCII characters. */
5721 /* Scan an ordered list of case nodes
5722 combining those with consecutive values or ranges.
5724 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
5727 group_case_nodes (head)
5730 case_node_ptr node = head;
5734 rtx lb = next_real_insn (label_rtx (node->code_label));
5736 case_node_ptr np = node;
5738 /* Try to group the successors of NODE with NODE. */
5739 while (((np = np->right) != 0)
5740 /* Do they jump to the same place? */
5741 && ((lb2 = next_real_insn (label_rtx (np->code_label))) == lb
5742 || (lb != 0 && lb2 != 0
5743 && simplejump_p (lb)
5744 && simplejump_p (lb2)
5745 && rtx_equal_p (SET_SRC (PATTERN (lb)),
5746 SET_SRC (PATTERN (lb2)))))
5747 /* Are their ranges consecutive? */
5748 && tree_int_cst_equal (np->low,
5749 fold (build (PLUS_EXPR,
5750 TREE_TYPE (node->high),
5753 /* An overflow is not consecutive. */
5754 && tree_int_cst_lt (node->high,
5755 fold (build (PLUS_EXPR,
5756 TREE_TYPE (node->high),
5758 integer_one_node))))
5760 node->high = np->high;
5762 /* NP is the first node after NODE which can't be grouped with it.
5763 Delete the nodes in between, and move on to that node. */
5769 /* Take an ordered list of case nodes
5770 and transform them into a near optimal binary tree,
5771 on the assumption that any target code selection value is as
5772 likely as any other.
5774 The transformation is performed by splitting the ordered
5775 list into two equal sections plus a pivot. The parts are
5776 then attached to the pivot as left and right branches. Each
5777 branch is then transformed recursively. */
5780 balance_case_nodes (head, parent)
5781 case_node_ptr *head;
5782 case_node_ptr parent;
5795 /* Count the number of entries on branch. Also count the ranges. */
5799 if (!tree_int_cst_equal (np->low, np->high))
5803 cost += COST_TABLE (TREE_INT_CST_LOW (np->high));
5807 cost += COST_TABLE (TREE_INT_CST_LOW (np->low));
5815 /* Split this list if it is long enough for that to help. */
5820 /* Find the place in the list that bisects the list's total cost,
5821 Here I gets half the total cost. */
5826 /* Skip nodes while their cost does not reach that amount. */
5827 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
5828 i -= COST_TABLE (TREE_INT_CST_LOW ((*npp)->high));
5829 i -= COST_TABLE (TREE_INT_CST_LOW ((*npp)->low));
5832 npp = &(*npp)->right;
5837 /* Leave this branch lopsided, but optimize left-hand
5838 side and fill in `parent' fields for right-hand side. */
5840 np->parent = parent;
5841 balance_case_nodes (&np->left, np);
5842 for (; np->right; np = np->right)
5843 np->right->parent = np;
5847 /* If there are just three nodes, split at the middle one. */
5849 npp = &(*npp)->right;
5852 /* Find the place in the list that bisects the list's total cost,
5853 where ranges count as 2.
5854 Here I gets half the total cost. */
5855 i = (i + ranges + 1) / 2;
5858 /* Skip nodes while their cost does not reach that amount. */
5859 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
5864 npp = &(*npp)->right;
5869 np->parent = parent;
5872 /* Optimize each of the two split parts. */
5873 balance_case_nodes (&np->left, np);
5874 balance_case_nodes (&np->right, np);
5878 /* Else leave this branch as one level,
5879 but fill in `parent' fields. */
5881 np->parent = parent;
5882 for (; np->right; np = np->right)
5883 np->right->parent = np;
5888 /* Search the parent sections of the case node tree
5889 to see if a test for the lower bound of NODE would be redundant.
5890 INDEX_TYPE is the type of the index expression.
5892 The instructions to generate the case decision tree are
5893 output in the same order as nodes are processed so it is
5894 known that if a parent node checks the range of the current
5895 node minus one that the current node is bounded at its lower
5896 span. Thus the test would be redundant. */
5899 node_has_low_bound (node, index_type)
5904 case_node_ptr pnode;
5906 /* If the lower bound of this node is the lowest value in the index type,
5907 we need not test it. */
5909 if (tree_int_cst_equal (node->low, TYPE_MIN_VALUE (index_type)))
5912 /* If this node has a left branch, the value at the left must be less
5913 than that at this node, so it cannot be bounded at the bottom and
5914 we need not bother testing any further. */
5919 low_minus_one = fold (build (MINUS_EXPR, TREE_TYPE (node->low),
5920 node->low, integer_one_node));
5922 /* If the subtraction above overflowed, we can't verify anything.
5923 Otherwise, look for a parent that tests our value - 1. */
5925 if (! tree_int_cst_lt (low_minus_one, node->low))
5928 for (pnode = node->parent; pnode; pnode = pnode->parent)
5929 if (tree_int_cst_equal (low_minus_one, pnode->high))
5935 /* Search the parent sections of the case node tree
5936 to see if a test for the upper bound of NODE would be redundant.
5937 INDEX_TYPE is the type of the index expression.
5939 The instructions to generate the case decision tree are
5940 output in the same order as nodes are processed so it is
5941 known that if a parent node checks the range of the current
5942 node plus one that the current node is bounded at its upper
5943 span. Thus the test would be redundant. */
5946 node_has_high_bound (node, index_type)
5951 case_node_ptr pnode;
5953 /* If there is no upper bound, obviously no test is needed. */
5955 if (TYPE_MAX_VALUE (index_type) == NULL)
5958 /* If the upper bound of this node is the highest value in the type
5959 of the index expression, we need not test against it. */
5961 if (tree_int_cst_equal (node->high, TYPE_MAX_VALUE (index_type)))
5964 /* If this node has a right branch, the value at the right must be greater
5965 than that at this node, so it cannot be bounded at the top and
5966 we need not bother testing any further. */
5971 high_plus_one = fold (build (PLUS_EXPR, TREE_TYPE (node->high),
5972 node->high, integer_one_node));
5974 /* If the addition above overflowed, we can't verify anything.
5975 Otherwise, look for a parent that tests our value + 1. */
5977 if (! tree_int_cst_lt (node->high, high_plus_one))
5980 for (pnode = node->parent; pnode; pnode = pnode->parent)
5981 if (tree_int_cst_equal (high_plus_one, pnode->low))
5987 /* Search the parent sections of the
5988 case node tree to see if both tests for the upper and lower
5989 bounds of NODE would be redundant. */
5992 node_is_bounded (node, index_type)
5996 return (node_has_low_bound (node, index_type)
5997 && node_has_high_bound (node, index_type));
6000 /* Emit an unconditional jump to LABEL unless it would be dead code. */
6003 emit_jump_if_reachable (label)
6006 if (GET_CODE (get_last_insn ()) != BARRIER)
6010 /* Emit step-by-step code to select a case for the value of INDEX.
6011 The thus generated decision tree follows the form of the
6012 case-node binary tree NODE, whose nodes represent test conditions.
6013 INDEX_TYPE is the type of the index of the switch.
6015 Care is taken to prune redundant tests from the decision tree
6016 by detecting any boundary conditions already checked by
6017 emitted rtx. (See node_has_high_bound, node_has_low_bound
6018 and node_is_bounded, above.)
6020 Where the test conditions can be shown to be redundant we emit
6021 an unconditional jump to the target code. As a further
6022 optimization, the subordinates of a tree node are examined to
6023 check for bounded nodes. In this case conditional and/or
6024 unconditional jumps as a result of the boundary check for the
6025 current node are arranged to target the subordinates associated
6026 code for out of bound conditions on the current node.
6028 We can assume that when control reaches the code generated here,
6029 the index value has already been compared with the parents
6030 of this node, and determined to be on the same side of each parent
6031 as this node is. Thus, if this node tests for the value 51,
6032 and a parent tested for 52, we don't need to consider
6033 the possibility of a value greater than 51. If another parent
6034 tests for the value 50, then this node need not test anything. */
6037 emit_case_nodes (index, node, default_label, index_type)
6043 /* If INDEX has an unsigned type, we must make unsigned branches. */
6044 int unsignedp = TREE_UNSIGNED (index_type);
6045 enum machine_mode mode = GET_MODE (index);
6046 enum machine_mode imode = TYPE_MODE (index_type);
6048 /* See if our parents have already tested everything for us.
6049 If they have, emit an unconditional jump for this node. */
6050 if (node_is_bounded (node, index_type))
6051 emit_jump (label_rtx (node->code_label));
6053 else if (tree_int_cst_equal (node->low, node->high))
6055 /* Node is single valued. First see if the index expression matches
6056 this node and then check our children, if any. */
6058 do_jump_if_equal (index,
6059 convert_modes (mode, imode,
6060 expand_expr (node->low, NULL_RTX,
6063 label_rtx (node->code_label), unsignedp);
6065 if (node->right != 0 && node->left != 0)
6067 /* This node has children on both sides.
6068 Dispatch to one side or the other
6069 by comparing the index value with this node's value.
6070 If one subtree is bounded, check that one first,
6071 so we can avoid real branches in the tree. */
6073 if (node_is_bounded (node->right, index_type))
6075 emit_cmp_and_jump_insns (index,
6078 expand_expr (node->high, NULL_RTX,
6081 GT, NULL_RTX, mode, unsignedp, 0,
6082 label_rtx (node->right->code_label));
6083 emit_case_nodes (index, node->left, default_label, index_type);
6086 else if (node_is_bounded (node->left, index_type))
6088 emit_cmp_and_jump_insns (index,
6091 expand_expr (node->high, NULL_RTX,
6094 LT, NULL_RTX, mode, unsignedp, 0,
6095 label_rtx (node->left->code_label));
6096 emit_case_nodes (index, node->right, default_label, index_type);
6101 /* Neither node is bounded. First distinguish the two sides;
6102 then emit the code for one side at a time. */
6104 tree test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
6106 /* See if the value is on the right. */
6107 emit_cmp_and_jump_insns (index,
6110 expand_expr (node->high, NULL_RTX,
6113 GT, NULL_RTX, mode, unsignedp, 0,
6114 label_rtx (test_label));
6116 /* Value must be on the left.
6117 Handle the left-hand subtree. */
6118 emit_case_nodes (index, node->left, default_label, index_type);
6119 /* If left-hand subtree does nothing,
6121 emit_jump_if_reachable (default_label);
6123 /* Code branches here for the right-hand subtree. */
6124 expand_label (test_label);
6125 emit_case_nodes (index, node->right, default_label, index_type);
6129 else if (node->right != 0 && node->left == 0)
6131 /* Here we have a right child but no left so we issue conditional
6132 branch to default and process the right child.
6134 Omit the conditional branch to default if we it avoid only one
6135 right child; it costs too much space to save so little time. */
6137 if (node->right->right || node->right->left
6138 || !tree_int_cst_equal (node->right->low, node->right->high))
6140 if (!node_has_low_bound (node, index_type))
6142 emit_cmp_and_jump_insns (index,
6145 expand_expr (node->high, NULL_RTX,
6148 LT, NULL_RTX, mode, unsignedp, 0,
6152 emit_case_nodes (index, node->right, default_label, index_type);
6155 /* We cannot process node->right normally
6156 since we haven't ruled out the numbers less than
6157 this node's value. So handle node->right explicitly. */
6158 do_jump_if_equal (index,
6161 expand_expr (node->right->low, NULL_RTX,
6164 label_rtx (node->right->code_label), unsignedp);
6167 else if (node->right == 0 && node->left != 0)
6169 /* Just one subtree, on the left. */
6170 if (node->left->left || node->left->right
6171 || !tree_int_cst_equal (node->left->low, node->left->high))
6173 if (!node_has_high_bound (node, index_type))
6175 emit_cmp_and_jump_insns (index,
6178 expand_expr (node->high, NULL_RTX,
6181 GT, NULL_RTX, mode, unsignedp, 0,
6185 emit_case_nodes (index, node->left, default_label, index_type);
6188 /* We cannot process node->left normally
6189 since we haven't ruled out the numbers less than
6190 this node's value. So handle node->left explicitly. */
6191 do_jump_if_equal (index,
6194 expand_expr (node->left->low, NULL_RTX,
6197 label_rtx (node->left->code_label), unsignedp);
6202 /* Node is a range. These cases are very similar to those for a single
6203 value, except that we do not start by testing whether this node
6204 is the one to branch to. */
6206 if (node->right != 0 && node->left != 0)
6208 /* Node has subtrees on both sides.
6209 If the right-hand subtree is bounded,
6210 test for it first, since we can go straight there.
6211 Otherwise, we need to make a branch in the control structure,
6212 then handle the two subtrees. */
6213 tree test_label = 0;
6215 if (node_is_bounded (node->right, index_type))
6216 /* Right hand node is fully bounded so we can eliminate any
6217 testing and branch directly to the target code. */
6218 emit_cmp_and_jump_insns (index,
6221 expand_expr (node->high, NULL_RTX,
6224 GT, NULL_RTX, mode, unsignedp, 0,
6225 label_rtx (node->right->code_label));
6228 /* Right hand node requires testing.
6229 Branch to a label where we will handle it later. */
6231 test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
6232 emit_cmp_and_jump_insns (index,
6235 expand_expr (node->high, NULL_RTX,
6238 GT, NULL_RTX, mode, unsignedp, 0,
6239 label_rtx (test_label));
6242 /* Value belongs to this node or to the left-hand subtree. */
6244 emit_cmp_and_jump_insns (index,
6247 expand_expr (node->low, NULL_RTX,
6250 GE, NULL_RTX, mode, unsignedp, 0,
6251 label_rtx (node->code_label));
6253 /* Handle the left-hand subtree. */
6254 emit_case_nodes (index, node->left, default_label, index_type);
6256 /* If right node had to be handled later, do that now. */
6260 /* If the left-hand subtree fell through,
6261 don't let it fall into the right-hand subtree. */
6262 emit_jump_if_reachable (default_label);
6264 expand_label (test_label);
6265 emit_case_nodes (index, node->right, default_label, index_type);
6269 else if (node->right != 0 && node->left == 0)
6271 /* Deal with values to the left of this node,
6272 if they are possible. */
6273 if (!node_has_low_bound (node, index_type))
6275 emit_cmp_and_jump_insns (index,
6278 expand_expr (node->low, NULL_RTX,
6281 LT, NULL_RTX, mode, unsignedp, 0,
6285 /* Value belongs to this node or to the right-hand subtree. */
6287 emit_cmp_and_jump_insns (index,
6290 expand_expr (node->high, NULL_RTX,
6293 LE, NULL_RTX, mode, unsignedp, 0,
6294 label_rtx (node->code_label));
6296 emit_case_nodes (index, node->right, default_label, index_type);
6299 else if (node->right == 0 && node->left != 0)
6301 /* Deal with values to the right of this node,
6302 if they are possible. */
6303 if (!node_has_high_bound (node, index_type))
6305 emit_cmp_and_jump_insns (index,
6308 expand_expr (node->high, NULL_RTX,
6311 GT, NULL_RTX, mode, unsignedp, 0,
6315 /* Value belongs to this node or to the left-hand subtree. */
6317 emit_cmp_and_jump_insns (index,
6320 expand_expr (node->low, NULL_RTX,
6323 GE, NULL_RTX, mode, unsignedp, 0,
6324 label_rtx (node->code_label));
6326 emit_case_nodes (index, node->left, default_label, index_type);
6331 /* Node has no children so we check low and high bounds to remove
6332 redundant tests. Only one of the bounds can exist,
6333 since otherwise this node is bounded--a case tested already. */
6334 int high_bound = node_has_high_bound (node, index_type);
6335 int low_bound = node_has_low_bound (node, index_type);
6337 if (!high_bound && low_bound)
6339 emit_cmp_and_jump_insns (index,
6342 expand_expr (node->high, NULL_RTX,
6345 GT, NULL_RTX, mode, unsignedp, 0,
6349 else if (!low_bound && high_bound)
6351 emit_cmp_and_jump_insns (index,
6354 expand_expr (node->low, NULL_RTX,
6357 LT, NULL_RTX, mode, unsignedp, 0,
6360 else if (!low_bound && !high_bound)
6362 /* Widen LOW and HIGH to the same width as INDEX. */
6363 tree type = type_for_mode (mode, unsignedp);
6364 tree low = build1 (CONVERT_EXPR, type, node->low);
6365 tree high = build1 (CONVERT_EXPR, type, node->high);
6366 rtx low_rtx, new_index, new_bound;
6368 /* Instead of doing two branches, emit one unsigned branch for
6369 (index-low) > (high-low). */
6370 low_rtx = expand_expr (low, NULL_RTX, mode, 0);
6371 new_index = expand_simple_binop (mode, MINUS, index, low_rtx,
6372 NULL_RTX, unsignedp,
6374 new_bound = expand_expr (fold (build (MINUS_EXPR, type,
6378 emit_cmp_and_jump_insns (new_index, new_bound, GT, NULL_RTX,
6379 mode, 1, 0, default_label);
6382 emit_jump (label_rtx (node->code_label));