1 /* Expands front end tree to back end RTL for GCC
2 Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997,
3 1998, 1999, 2000, 2001, 2002, 2003, 2004 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 The functions whose names start with `expand_' are called by the
25 expander to generate RTL instructions for various kinds of constructs. */
29 #include "coretypes.h"
38 #include "insn-config.h"
41 #include "hard-reg-set.h"
48 #include "langhooks.h"
54 /* Functions and data structures for expanding case statements. */
56 /* Case label structure, used to hold info on labels within case
57 statements. We handle "range" labels; for a single-value label
58 as in C, the high and low limits are the same.
60 We start with a vector of case nodes sorted in ascending order, and
61 the default label as the last element in the vector. Before expanding
62 to RTL, we transform this vector into a list linked via the RIGHT
63 fields in the case_node struct. Nodes with higher case values are
66 Switch statements can be output in three forms. A branch table is
67 used if there are more than a few labels and the labels are dense
68 within the range between the smallest and largest case value. If a
69 branch table is used, no further manipulations are done with the case
72 The alternative to the use of a branch table is to generate a series
73 of compare and jump insns. When that is done, we use the LEFT, RIGHT,
74 and PARENT fields to hold a binary tree. Initially the tree is
75 totally unbalanced, with everything on the right. We balance the tree
76 with nodes on the left having lower case values than the parent
77 and nodes on the right having higher values. We then output the tree
80 For very small, suitable switch statements, we can generate a series
81 of simple bit test and branches instead. */
83 struct case_node GTY(())
85 struct case_node *left; /* Left son in binary tree */
86 struct case_node *right; /* Right son in binary tree; also node chain */
87 struct case_node *parent; /* Parent of node in binary tree */
88 tree low; /* Lowest index value for this label */
89 tree high; /* Highest index value for this label */
90 tree code_label; /* Label to jump to when node matches */
93 typedef struct case_node case_node;
94 typedef struct case_node *case_node_ptr;
96 /* These are used by estimate_case_costs and balance_case_nodes. */
98 /* This must be a signed type, and non-ANSI compilers lack signed char. */
99 static short cost_table_[129];
100 static int use_cost_table;
101 static int cost_table_initialized;
103 /* Special care is needed because we allow -1, but TREE_INT_CST_LOW
105 #define COST_TABLE(I) cost_table_[(unsigned HOST_WIDE_INT) ((I) + 1)]
107 static int n_occurrences (int, const char *);
108 static bool decl_conflicts_with_clobbers_p (tree, const HARD_REG_SET);
109 static void expand_nl_goto_receiver (void);
110 static bool check_operand_nalternatives (tree, tree);
111 static bool check_unique_operand_names (tree, tree);
112 static char *resolve_operand_name_1 (char *, tree, tree);
113 static void expand_null_return_1 (void);
114 static rtx shift_return_value (rtx);
115 static void expand_value_return (rtx);
116 static void do_jump_if_equal (rtx, rtx, rtx, int);
117 static int estimate_case_costs (case_node_ptr);
118 static bool lshift_cheap_p (void);
119 static int case_bit_test_cmp (const void *, const void *);
120 static void emit_case_bit_tests (tree, tree, tree, tree, case_node_ptr, rtx);
121 static void balance_case_nodes (case_node_ptr *, case_node_ptr);
122 static int node_has_low_bound (case_node_ptr, tree);
123 static int node_has_high_bound (case_node_ptr, tree);
124 static int node_is_bounded (case_node_ptr, tree);
125 static void emit_case_nodes (rtx, case_node_ptr, rtx, tree);
126 static struct case_node *add_case_node (struct case_node *, tree, tree, tree);
129 /* Return the rtx-label that corresponds to a LABEL_DECL,
130 creating it if necessary. */
133 label_rtx (tree label)
135 if (TREE_CODE (label) != LABEL_DECL)
138 if (!DECL_RTL_SET_P (label))
140 rtx r = gen_label_rtx ();
141 SET_DECL_RTL (label, r);
142 if (FORCED_LABEL (label) || DECL_NONLOCAL (label))
143 LABEL_PRESERVE_P (r) = 1;
146 return DECL_RTL (label);
149 /* As above, but also put it on the forced-reference list of the
150 function that contains it. */
152 force_label_rtx (tree label)
154 rtx ref = label_rtx (label);
155 tree function = decl_function_context (label);
161 if (function != current_function_decl)
162 p = find_function_data (function);
166 p->expr->x_forced_labels = gen_rtx_EXPR_LIST (VOIDmode, ref,
167 p->expr->x_forced_labels);
171 /* Add an unconditional jump to LABEL as the next sequential instruction. */
174 emit_jump (rtx label)
176 do_pending_stack_adjust ();
177 emit_jump_insn (gen_jump (label));
181 /* Emit code to jump to the address
182 specified by the pointer expression EXP. */
185 expand_computed_goto (tree exp)
187 rtx x = expand_expr (exp, NULL_RTX, VOIDmode, 0);
189 x = convert_memory_address (Pmode, x);
191 do_pending_stack_adjust ();
192 emit_indirect_jump (x);
195 /* Handle goto statements and the labels that they can go to. */
197 /* Specify the location in the RTL code of a label LABEL,
198 which is a LABEL_DECL tree node.
200 This is used for the kind of label that the user can jump to with a
201 goto statement, and for alternatives of a switch or case statement.
202 RTL labels generated for loops and conditionals don't go through here;
203 they are generated directly at the RTL level, by other functions below.
205 Note that this has nothing to do with defining label *names*.
206 Languages vary in how they do that and what that even means. */
209 expand_label (tree label)
211 rtx label_r = label_rtx (label);
213 do_pending_stack_adjust ();
214 emit_label (label_r);
215 if (DECL_NAME (label))
216 LABEL_NAME (DECL_RTL (label)) = IDENTIFIER_POINTER (DECL_NAME (label));
218 if (DECL_NONLOCAL (label))
220 expand_nl_goto_receiver ();
221 nonlocal_goto_handler_labels
222 = gen_rtx_EXPR_LIST (VOIDmode, label_r,
223 nonlocal_goto_handler_labels);
226 if (FORCED_LABEL (label))
227 forced_labels = gen_rtx_EXPR_LIST (VOIDmode, label_r, forced_labels);
229 if (DECL_NONLOCAL (label) || FORCED_LABEL (label))
230 maybe_set_first_label_num (label_r);
233 /* Generate RTL code for a `goto' statement with target label LABEL.
234 LABEL should be a LABEL_DECL tree node that was or will later be
235 defined with `expand_label'. */
238 expand_goto (tree label)
240 #ifdef ENABLE_CHECKING
241 /* Check for a nonlocal goto to a containing function. Should have
242 gotten translated to __builtin_nonlocal_goto. */
243 tree context = decl_function_context (label);
244 if (context != 0 && context != current_function_decl)
248 emit_jump (label_rtx (label));
251 /* Return the number of times character C occurs in string S. */
253 n_occurrences (int c, const char *s)
261 /* Generate RTL for an asm statement (explicit assembler code).
262 STRING is a STRING_CST node containing the assembler code text,
263 or an ADDR_EXPR containing a STRING_CST. VOL nonzero means the
264 insn is volatile; don't optimize it. */
267 expand_asm (tree string, int vol)
271 if (TREE_CODE (string) == ADDR_EXPR)
272 string = TREE_OPERAND (string, 0);
274 body = gen_rtx_ASM_INPUT (VOIDmode, TREE_STRING_POINTER (string));
276 MEM_VOLATILE_P (body) = vol;
281 /* Parse the output constraint pointed to by *CONSTRAINT_P. It is the
282 OPERAND_NUMth output operand, indexed from zero. There are NINPUTS
283 inputs and NOUTPUTS outputs to this extended-asm. Upon return,
284 *ALLOWS_MEM will be TRUE iff the constraint allows the use of a
285 memory operand. Similarly, *ALLOWS_REG will be TRUE iff the
286 constraint allows the use of a register operand. And, *IS_INOUT
287 will be true if the operand is read-write, i.e., if it is used as
288 an input as well as an output. If *CONSTRAINT_P is not in
289 canonical form, it will be made canonical. (Note that `+' will be
290 replaced with `=' as part of this process.)
292 Returns TRUE if all went well; FALSE if an error occurred. */
295 parse_output_constraint (const char **constraint_p, int operand_num,
296 int ninputs, int noutputs, bool *allows_mem,
297 bool *allows_reg, bool *is_inout)
299 const char *constraint = *constraint_p;
302 /* Assume the constraint doesn't allow the use of either a register
307 /* Allow the `=' or `+' to not be at the beginning of the string,
308 since it wasn't explicitly documented that way, and there is a
309 large body of code that puts it last. Swap the character to
310 the front, so as not to uglify any place else. */
311 p = strchr (constraint, '=');
313 p = strchr (constraint, '+');
315 /* If the string doesn't contain an `=', issue an error
319 error ("output operand constraint lacks `='");
323 /* If the constraint begins with `+', then the operand is both read
324 from and written to. */
325 *is_inout = (*p == '+');
327 /* Canonicalize the output constraint so that it begins with `='. */
328 if (p != constraint || is_inout)
331 size_t c_len = strlen (constraint);
334 warning ("output constraint `%c' for operand %d is not at the beginning",
337 /* Make a copy of the constraint. */
338 buf = alloca (c_len + 1);
339 strcpy (buf, constraint);
340 /* Swap the first character and the `=' or `+'. */
341 buf[p - constraint] = buf[0];
342 /* Make sure the first character is an `='. (Until we do this,
343 it might be a `+'.) */
345 /* Replace the constraint with the canonicalized string. */
346 *constraint_p = ggc_alloc_string (buf, c_len);
347 constraint = *constraint_p;
350 /* Loop through the constraint string. */
351 for (p = constraint + 1; *p; p += CONSTRAINT_LEN (*p, p))
356 error ("operand constraint contains incorrectly positioned '+' or '='");
360 if (operand_num + 1 == ninputs + noutputs)
362 error ("`%%' constraint used with last operand");
367 case 'V': case 'm': case 'o':
371 case '?': case '!': case '*': case '&': case '#':
372 case 'E': case 'F': case 'G': case 'H':
373 case 's': case 'i': case 'n':
374 case 'I': case 'J': case 'K': case 'L': case 'M':
375 case 'N': case 'O': case 'P': case ',':
378 case '0': case '1': case '2': case '3': case '4':
379 case '5': case '6': case '7': case '8': case '9':
381 error ("matching constraint not valid in output operand");
385 /* ??? Before flow, auto inc/dec insns are not supposed to exist,
386 excepting those that expand_call created. So match memory
403 if (REG_CLASS_FROM_CONSTRAINT (*p, p) != NO_REGS)
405 #ifdef EXTRA_CONSTRAINT_STR
406 else if (EXTRA_ADDRESS_CONSTRAINT (*p, p))
408 else if (EXTRA_MEMORY_CONSTRAINT (*p, p))
412 /* Otherwise we can't assume anything about the nature of
413 the constraint except that it isn't purely registers.
414 Treat it like "g" and hope for the best. */
425 /* Similar, but for input constraints. */
428 parse_input_constraint (const char **constraint_p, int input_num,
429 int ninputs, int noutputs, int ninout,
430 const char * const * constraints,
431 bool *allows_mem, bool *allows_reg)
433 const char *constraint = *constraint_p;
434 const char *orig_constraint = constraint;
435 size_t c_len = strlen (constraint);
437 bool saw_match = false;
439 /* Assume the constraint doesn't allow the use of either
440 a register or memory. */
444 /* Make sure constraint has neither `=', `+', nor '&'. */
446 for (j = 0; j < c_len; j += CONSTRAINT_LEN (constraint[j], constraint+j))
447 switch (constraint[j])
449 case '+': case '=': case '&':
450 if (constraint == orig_constraint)
452 error ("input operand constraint contains `%c'", constraint[j]);
458 if (constraint == orig_constraint
459 && input_num + 1 == ninputs - ninout)
461 error ("`%%' constraint used with last operand");
466 case 'V': case 'm': case 'o':
471 case '?': case '!': case '*': case '#':
472 case 'E': case 'F': case 'G': case 'H':
473 case 's': case 'i': case 'n':
474 case 'I': case 'J': case 'K': case 'L': case 'M':
475 case 'N': case 'O': case 'P': case ',':
478 /* Whether or not a numeric constraint allows a register is
479 decided by the matching constraint, and so there is no need
480 to do anything special with them. We must handle them in
481 the default case, so that we don't unnecessarily force
482 operands to memory. */
483 case '0': case '1': case '2': case '3': case '4':
484 case '5': case '6': case '7': case '8': case '9':
491 match = strtoul (constraint + j, &end, 10);
492 if (match >= (unsigned long) noutputs)
494 error ("matching constraint references invalid operand number");
498 /* Try and find the real constraint for this dup. Only do this
499 if the matching constraint is the only alternative. */
501 && (j == 0 || (j == 1 && constraint[0] == '%')))
503 constraint = constraints[match];
504 *constraint_p = constraint;
505 c_len = strlen (constraint);
507 /* ??? At the end of the loop, we will skip the first part of
508 the matched constraint. This assumes not only that the
509 other constraint is an output constraint, but also that
510 the '=' or '+' come first. */
514 j = end - constraint;
515 /* Anticipate increment at end of loop. */
530 if (! ISALPHA (constraint[j]))
532 error ("invalid punctuation `%c' in constraint", constraint[j]);
535 if (REG_CLASS_FROM_CONSTRAINT (constraint[j], constraint + j)
538 #ifdef EXTRA_CONSTRAINT_STR
539 else if (EXTRA_ADDRESS_CONSTRAINT (constraint[j], constraint + j))
541 else if (EXTRA_MEMORY_CONSTRAINT (constraint[j], constraint + j))
545 /* Otherwise we can't assume anything about the nature of
546 the constraint except that it isn't purely registers.
547 Treat it like "g" and hope for the best. */
555 if (saw_match && !*allows_reg)
556 warning ("matching constraint does not allow a register");
561 /* INPUT is one of the input operands from EXPR, an ASM_EXPR. Returns true
562 if it is an operand which must be passed in memory (i.e. an "m"
563 constraint), false otherwise. */
566 asm_op_is_mem_input (tree input, tree expr)
568 const char *constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (input)));
569 tree outputs = ASM_OUTPUTS (expr);
570 int noutputs = list_length (outputs);
571 const char **constraints
572 = (const char **) alloca ((noutputs) * sizeof (const char *));
574 bool allows_mem, allows_reg;
577 /* Collect output constraints. */
578 for (t = outputs; t ; t = TREE_CHAIN (t), i++)
579 constraints[i] = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
581 /* We pass 0 for input_num, ninputs and ninout; they are only used for
582 error checking which will be done at expand time. */
583 parse_input_constraint (&constraint, 0, 0, noutputs, 0, constraints,
584 &allows_mem, &allows_reg);
585 return (!allows_reg && allows_mem);
588 /* Check for overlap between registers marked in CLOBBERED_REGS and
589 anything inappropriate in DECL. Emit error and return TRUE for error,
593 decl_conflicts_with_clobbers_p (tree decl, const HARD_REG_SET clobbered_regs)
595 /* Conflicts between asm-declared register variables and the clobber
596 list are not allowed. */
597 if ((TREE_CODE (decl) == VAR_DECL || TREE_CODE (decl) == PARM_DECL)
598 && DECL_REGISTER (decl)
599 && REG_P (DECL_RTL (decl))
600 && REGNO (DECL_RTL (decl)) < FIRST_PSEUDO_REGISTER)
602 rtx reg = DECL_RTL (decl);
605 for (regno = REGNO (reg);
607 + hard_regno_nregs[REGNO (reg)][GET_MODE (reg)]);
609 if (TEST_HARD_REG_BIT (clobbered_regs, regno))
611 error ("asm-specifier for variable `%s' conflicts with asm clobber list",
612 IDENTIFIER_POINTER (DECL_NAME (decl)));
614 /* Reset registerness to stop multiple errors emitted for a
616 DECL_REGISTER (decl) = 0;
623 /* Generate RTL for an asm statement with arguments.
624 STRING is the instruction template.
625 OUTPUTS is a list of output arguments (lvalues); INPUTS a list of inputs.
626 Each output or input has an expression in the TREE_VALUE and
627 and a tree list in TREE_PURPOSE which in turn contains a constraint
628 name in TREE_VALUE (or NULL_TREE) and a constraint string
630 CLOBBERS is a list of STRING_CST nodes each naming a hard register
631 that is clobbered by this insn.
633 Not all kinds of lvalue that may appear in OUTPUTS can be stored directly.
634 Some elements of OUTPUTS may be replaced with trees representing temporary
635 values. The caller should copy those temporary values to the originally
638 VOL nonzero means the insn is volatile; don't optimize it. */
641 expand_asm_operands (tree string, tree outputs, tree inputs,
642 tree clobbers, int vol, location_t locus)
644 rtvec argvec, constraintvec;
646 int ninputs = list_length (inputs);
647 int noutputs = list_length (outputs);
650 HARD_REG_SET clobbered_regs;
651 int clobber_conflict_found = 0;
655 /* Vector of RTX's of evaluated output operands. */
656 rtx *output_rtx = alloca (noutputs * sizeof (rtx));
657 int *inout_opnum = alloca (noutputs * sizeof (int));
658 rtx *real_output_rtx = alloca (noutputs * sizeof (rtx));
659 enum machine_mode *inout_mode
660 = alloca (noutputs * sizeof (enum machine_mode));
661 const char **constraints
662 = alloca ((noutputs + ninputs) * sizeof (const char *));
663 int old_generating_concat_p = generating_concat_p;
665 /* An ASM with no outputs needs to be treated as volatile, for now. */
669 if (! check_operand_nalternatives (outputs, inputs))
672 string = resolve_asm_operand_names (string, outputs, inputs);
674 /* Collect constraints. */
676 for (t = outputs; t ; t = TREE_CHAIN (t), i++)
677 constraints[i] = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
678 for (t = inputs; t ; t = TREE_CHAIN (t), i++)
679 constraints[i] = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
681 /* Sometimes we wish to automatically clobber registers across an asm.
682 Case in point is when the i386 backend moved from cc0 to a hard reg --
683 maintaining source-level compatibility means automatically clobbering
684 the flags register. */
685 clobbers = targetm.md_asm_clobbers (clobbers);
687 /* Count the number of meaningful clobbered registers, ignoring what
688 we would ignore later. */
690 CLEAR_HARD_REG_SET (clobbered_regs);
691 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
693 const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
695 i = decode_reg_name (regname);
696 if (i >= 0 || i == -4)
699 error ("unknown register name `%s' in `asm'", regname);
701 /* Mark clobbered registers. */
704 /* Clobbering the PIC register is an error */
705 if (i == (int) PIC_OFFSET_TABLE_REGNUM)
707 error ("PIC register `%s' clobbered in `asm'", regname);
711 SET_HARD_REG_BIT (clobbered_regs, i);
715 /* First pass over inputs and outputs checks validity and sets
716 mark_addressable if needed. */
719 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
721 tree val = TREE_VALUE (tail);
722 tree type = TREE_TYPE (val);
723 const char *constraint;
728 /* If there's an erroneous arg, emit no insn. */
729 if (type == error_mark_node)
732 /* Try to parse the output constraint. If that fails, there's
733 no point in going further. */
734 constraint = constraints[i];
735 if (!parse_output_constraint (&constraint, i, ninputs, noutputs,
736 &allows_mem, &allows_reg, &is_inout))
743 && REG_P (DECL_RTL (val))
744 && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type))))
745 lang_hooks.mark_addressable (val);
752 if (ninputs + noutputs > MAX_RECOG_OPERANDS)
754 error ("more than %d operands in `asm'", MAX_RECOG_OPERANDS);
758 for (i = 0, tail = inputs; tail; i++, tail = TREE_CHAIN (tail))
760 bool allows_reg, allows_mem;
761 const char *constraint;
763 /* If there's an erroneous arg, emit no insn, because the ASM_INPUT
764 would get VOIDmode and that could cause a crash in reload. */
765 if (TREE_TYPE (TREE_VALUE (tail)) == error_mark_node)
768 constraint = constraints[i + noutputs];
769 if (! parse_input_constraint (&constraint, i, ninputs, noutputs, ninout,
770 constraints, &allows_mem, &allows_reg))
773 if (! allows_reg && allows_mem)
774 lang_hooks.mark_addressable (TREE_VALUE (tail));
777 /* Second pass evaluates arguments. */
780 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
782 tree val = TREE_VALUE (tail);
783 tree type = TREE_TYPE (val);
789 if (!parse_output_constraint (&constraints[i], i, ninputs,
790 noutputs, &allows_mem, &allows_reg,
794 /* If an output operand is not a decl or indirect ref and our constraint
795 allows a register, make a temporary to act as an intermediate.
796 Make the asm insn write into that, then our caller will copy it to
797 the real output operand. Likewise for promoted variables. */
799 generating_concat_p = 0;
801 real_output_rtx[i] = NULL_RTX;
802 if ((TREE_CODE (val) == INDIRECT_REF
805 && (allows_mem || REG_P (DECL_RTL (val)))
806 && ! (REG_P (DECL_RTL (val))
807 && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type)))
811 op = expand_expr (val, NULL_RTX, VOIDmode, EXPAND_WRITE);
813 op = validize_mem (op);
815 if (! allows_reg && !MEM_P (op))
816 error ("output number %d not directly addressable", i);
817 if ((! allows_mem && MEM_P (op))
818 || GET_CODE (op) == CONCAT)
820 real_output_rtx[i] = op;
821 op = gen_reg_rtx (GET_MODE (op));
823 emit_move_insn (op, real_output_rtx[i]);
828 op = assign_temp (type, 0, 0, 1);
829 op = validize_mem (op);
830 TREE_VALUE (tail) = make_tree (type, op);
834 generating_concat_p = old_generating_concat_p;
838 inout_mode[ninout] = TYPE_MODE (type);
839 inout_opnum[ninout++] = i;
842 if (decl_conflicts_with_clobbers_p (val, clobbered_regs))
843 clobber_conflict_found = 1;
846 /* Make vectors for the expression-rtx, constraint strings,
847 and named operands. */
849 argvec = rtvec_alloc (ninputs);
850 constraintvec = rtvec_alloc (ninputs);
852 body = gen_rtx_ASM_OPERANDS ((noutputs == 0 ? VOIDmode
853 : GET_MODE (output_rtx[0])),
854 TREE_STRING_POINTER (string),
855 empty_string, 0, argvec, constraintvec,
858 MEM_VOLATILE_P (body) = vol;
860 /* Eval the inputs and put them into ARGVEC.
861 Put their constraints into ASM_INPUTs and store in CONSTRAINTS. */
863 for (i = 0, tail = inputs; tail; tail = TREE_CHAIN (tail), ++i)
865 bool allows_reg, allows_mem;
866 const char *constraint;
870 constraint = constraints[i + noutputs];
871 if (! parse_input_constraint (&constraint, i, ninputs, noutputs, ninout,
872 constraints, &allows_mem, &allows_reg))
875 generating_concat_p = 0;
877 val = TREE_VALUE (tail);
878 type = TREE_TYPE (val);
879 op = expand_expr (val, NULL_RTX, VOIDmode,
880 (allows_mem && !allows_reg
881 ? EXPAND_MEMORY : EXPAND_NORMAL));
883 /* Never pass a CONCAT to an ASM. */
884 if (GET_CODE (op) == CONCAT)
885 op = force_reg (GET_MODE (op), op);
887 op = validize_mem (op);
889 if (asm_operand_ok (op, constraint) <= 0)
892 op = force_reg (TYPE_MODE (type), op);
893 else if (!allows_mem)
894 warning ("asm operand %d probably doesn't match constraints",
898 /* We won't recognize either volatile memory or memory
899 with a queued address as available a memory_operand
900 at this point. Ignore it: clearly this *is* a memory. */
904 warning ("use of memory input without lvalue in "
905 "asm operand %d is deprecated", i + noutputs);
909 rtx mem = force_const_mem (TYPE_MODE (type), op);
911 op = validize_mem (mem);
913 op = force_reg (TYPE_MODE (type), op);
916 || GET_CODE (op) == SUBREG
917 || GET_CODE (op) == CONCAT)
919 tree qual_type = build_qualified_type (type,
922 rtx memloc = assign_temp (qual_type, 1, 1, 1);
923 memloc = validize_mem (memloc);
924 emit_move_insn (memloc, op);
930 generating_concat_p = old_generating_concat_p;
931 ASM_OPERANDS_INPUT (body, i) = op;
933 ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, i)
934 = gen_rtx_ASM_INPUT (TYPE_MODE (type), constraints[i + noutputs]);
936 if (decl_conflicts_with_clobbers_p (val, clobbered_regs))
937 clobber_conflict_found = 1;
940 /* Protect all the operands from the queue now that they have all been
943 generating_concat_p = 0;
945 /* For in-out operands, copy output rtx to input rtx. */
946 for (i = 0; i < ninout; i++)
948 int j = inout_opnum[i];
951 ASM_OPERANDS_INPUT (body, ninputs - ninout + i)
954 sprintf (buffer, "%d", j);
955 ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, ninputs - ninout + i)
956 = gen_rtx_ASM_INPUT (inout_mode[i], ggc_strdup (buffer));
959 generating_concat_p = old_generating_concat_p;
961 /* Now, for each output, construct an rtx
962 (set OUTPUT (asm_operands INSN OUTPUTCONSTRAINT OUTPUTNUMBER
963 ARGVEC CONSTRAINTS OPNAMES))
964 If there is more than one, put them inside a PARALLEL. */
966 if (noutputs == 1 && nclobbers == 0)
968 ASM_OPERANDS_OUTPUT_CONSTRAINT (body) = constraints[0];
969 emit_insn (gen_rtx_SET (VOIDmode, output_rtx[0], body));
972 else if (noutputs == 0 && nclobbers == 0)
974 /* No output operands: put in a raw ASM_OPERANDS rtx. */
986 body = gen_rtx_PARALLEL (VOIDmode, rtvec_alloc (num + nclobbers));
988 /* For each output operand, store a SET. */
989 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
992 = gen_rtx_SET (VOIDmode,
995 (GET_MODE (output_rtx[i]),
996 TREE_STRING_POINTER (string),
997 constraints[i], i, argvec, constraintvec,
1000 MEM_VOLATILE_P (SET_SRC (XVECEXP (body, 0, i))) = vol;
1003 /* If there are no outputs (but there are some clobbers)
1004 store the bare ASM_OPERANDS into the PARALLEL. */
1007 XVECEXP (body, 0, i++) = obody;
1009 /* Store (clobber REG) for each clobbered register specified. */
1011 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1013 const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1014 int j = decode_reg_name (regname);
1019 if (j == -3) /* `cc', which is not a register */
1022 if (j == -4) /* `memory', don't cache memory across asm */
1024 XVECEXP (body, 0, i++)
1025 = gen_rtx_CLOBBER (VOIDmode,
1028 gen_rtx_SCRATCH (VOIDmode)));
1032 /* Ignore unknown register, error already signaled. */
1036 /* Use QImode since that's guaranteed to clobber just one reg. */
1037 clobbered_reg = gen_rtx_REG (QImode, j);
1039 /* Do sanity check for overlap between clobbers and respectively
1040 input and outputs that hasn't been handled. Such overlap
1041 should have been detected and reported above. */
1042 if (!clobber_conflict_found)
1046 /* We test the old body (obody) contents to avoid tripping
1047 over the under-construction body. */
1048 for (opno = 0; opno < noutputs; opno++)
1049 if (reg_overlap_mentioned_p (clobbered_reg, output_rtx[opno]))
1050 internal_error ("asm clobber conflict with output operand");
1052 for (opno = 0; opno < ninputs - ninout; opno++)
1053 if (reg_overlap_mentioned_p (clobbered_reg,
1054 ASM_OPERANDS_INPUT (obody, opno)))
1055 internal_error ("asm clobber conflict with input operand");
1058 XVECEXP (body, 0, i++)
1059 = gen_rtx_CLOBBER (VOIDmode, clobbered_reg);
1065 /* For any outputs that needed reloading into registers, spill them
1066 back to where they belong. */
1067 for (i = 0; i < noutputs; ++i)
1068 if (real_output_rtx[i])
1069 emit_move_insn (real_output_rtx[i], output_rtx[i]);
1075 expand_asm_expr (tree exp)
1081 if (ASM_INPUT_P (exp))
1083 expand_asm (ASM_STRING (exp), ASM_VOLATILE_P (exp));
1087 outputs = ASM_OUTPUTS (exp);
1088 noutputs = list_length (outputs);
1089 /* o[I] is the place that output number I should be written. */
1090 o = (tree *) alloca (noutputs * sizeof (tree));
1092 /* Record the contents of OUTPUTS before it is modified. */
1093 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1094 o[i] = TREE_VALUE (tail);
1096 /* Generate the ASM_OPERANDS insn; store into the TREE_VALUEs of
1097 OUTPUTS some trees for where the values were actually stored. */
1098 expand_asm_operands (ASM_STRING (exp), outputs, ASM_INPUTS (exp),
1099 ASM_CLOBBERS (exp), ASM_VOLATILE_P (exp),
1102 /* Copy all the intermediate outputs into the specified outputs. */
1103 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1105 if (o[i] != TREE_VALUE (tail))
1107 expand_assignment (o[i], TREE_VALUE (tail), 0);
1110 /* Restore the original value so that it's correct the next
1111 time we expand this function. */
1112 TREE_VALUE (tail) = o[i];
1117 /* A subroutine of expand_asm_operands. Check that all operands have
1118 the same number of alternatives. Return true if so. */
1121 check_operand_nalternatives (tree outputs, tree inputs)
1123 if (outputs || inputs)
1125 tree tmp = TREE_PURPOSE (outputs ? outputs : inputs);
1127 = n_occurrences (',', TREE_STRING_POINTER (TREE_VALUE (tmp)));
1130 if (nalternatives + 1 > MAX_RECOG_ALTERNATIVES)
1132 error ("too many alternatives in `asm'");
1139 const char *constraint
1140 = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tmp)));
1142 if (n_occurrences (',', constraint) != nalternatives)
1144 error ("operand constraints for `asm' differ in number of alternatives");
1148 if (TREE_CHAIN (tmp))
1149 tmp = TREE_CHAIN (tmp);
1151 tmp = next, next = 0;
1158 /* A subroutine of expand_asm_operands. Check that all operand names
1159 are unique. Return true if so. We rely on the fact that these names
1160 are identifiers, and so have been canonicalized by get_identifier,
1161 so all we need are pointer comparisons. */
1164 check_unique_operand_names (tree outputs, tree inputs)
1168 for (i = outputs; i ; i = TREE_CHAIN (i))
1170 tree i_name = TREE_PURPOSE (TREE_PURPOSE (i));
1174 for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
1175 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1179 for (i = inputs; i ; i = TREE_CHAIN (i))
1181 tree i_name = TREE_PURPOSE (TREE_PURPOSE (i));
1185 for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
1186 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1188 for (j = outputs; j ; j = TREE_CHAIN (j))
1189 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1196 error ("duplicate asm operand name '%s'",
1197 TREE_STRING_POINTER (TREE_PURPOSE (TREE_PURPOSE (i))));
1201 /* A subroutine of expand_asm_operands. Resolve the names of the operands
1202 in *POUTPUTS and *PINPUTS to numbers, and replace the name expansions in
1203 STRING and in the constraints to those numbers. */
1206 resolve_asm_operand_names (tree string, tree outputs, tree inputs)
1213 check_unique_operand_names (outputs, inputs);
1215 /* Substitute [<name>] in input constraint strings. There should be no
1216 named operands in output constraints. */
1217 for (t = inputs; t ; t = TREE_CHAIN (t))
1219 c = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
1220 if (strchr (c, '[') != NULL)
1222 p = buffer = xstrdup (c);
1223 while ((p = strchr (p, '[')) != NULL)
1224 p = resolve_operand_name_1 (p, outputs, inputs);
1225 TREE_VALUE (TREE_PURPOSE (t))
1226 = build_string (strlen (buffer), buffer);
1231 /* Now check for any needed substitutions in the template. */
1232 c = TREE_STRING_POINTER (string);
1233 while ((c = strchr (c, '%')) != NULL)
1237 else if (ISALPHA (c[1]) && c[2] == '[')
1248 /* OK, we need to make a copy so we can perform the substitutions.
1249 Assume that we will not need extra space--we get to remove '['
1250 and ']', which means we cannot have a problem until we have more
1251 than 999 operands. */
1252 buffer = xstrdup (TREE_STRING_POINTER (string));
1253 p = buffer + (c - TREE_STRING_POINTER (string));
1255 while ((p = strchr (p, '%')) != NULL)
1259 else if (ISALPHA (p[1]) && p[2] == '[')
1267 p = resolve_operand_name_1 (p, outputs, inputs);
1270 string = build_string (strlen (buffer), buffer);
1277 /* A subroutine of resolve_operand_names. P points to the '[' for a
1278 potential named operand of the form [<name>]. In place, replace
1279 the name and brackets with a number. Return a pointer to the
1280 balance of the string after substitution. */
1283 resolve_operand_name_1 (char *p, tree outputs, tree inputs)
1290 /* Collect the operand name. */
1291 q = strchr (p, ']');
1294 error ("missing close brace for named operand");
1295 return strchr (p, '\0');
1299 /* Resolve the name to a number. */
1300 for (op = 0, t = outputs; t ; t = TREE_CHAIN (t), op++)
1302 tree name = TREE_PURPOSE (TREE_PURPOSE (t));
1305 const char *c = TREE_STRING_POINTER (name);
1306 if (strncmp (c, p + 1, len) == 0 && c[len] == '\0')
1310 for (t = inputs; t ; t = TREE_CHAIN (t), op++)
1312 tree name = TREE_PURPOSE (TREE_PURPOSE (t));
1315 const char *c = TREE_STRING_POINTER (name);
1316 if (strncmp (c, p + 1, len) == 0 && c[len] == '\0')
1322 error ("undefined named operand '%s'", p + 1);
1326 /* Replace the name with the number. Unfortunately, not all libraries
1327 get the return value of sprintf correct, so search for the end of the
1328 generated string by hand. */
1329 sprintf (p, "%d", op);
1330 p = strchr (p, '\0');
1332 /* Verify the no extra buffer space assumption. */
1336 /* Shift the rest of the buffer down to fill the gap. */
1337 memmove (p, q + 1, strlen (q + 1) + 1);
1342 /* Generate RTL to evaluate the expression EXP. */
1345 expand_expr_stmt (tree exp)
1350 value = expand_expr (exp, const0_rtx, VOIDmode, 0);
1351 type = TREE_TYPE (exp);
1353 /* If all we do is reference a volatile value in memory,
1354 copy it to a register to be sure it is actually touched. */
1355 if (value && MEM_P (value) && TREE_THIS_VOLATILE (exp))
1357 if (TYPE_MODE (type) == VOIDmode)
1359 else if (TYPE_MODE (type) != BLKmode)
1360 value = copy_to_reg (value);
1363 rtx lab = gen_label_rtx ();
1365 /* Compare the value with itself to reference it. */
1366 emit_cmp_and_jump_insns (value, value, EQ,
1367 expand_expr (TYPE_SIZE (type),
1368 NULL_RTX, VOIDmode, 0),
1374 /* Free any temporaries used to evaluate this expression. */
1378 /* Warn if EXP contains any computations whose results are not used.
1379 Return 1 if a warning is printed; 0 otherwise. LOCUS is the
1380 (potential) location of the expression. */
1383 warn_if_unused_value (tree exp, location_t locus)
1386 if (TREE_USED (exp))
1389 /* Don't warn about void constructs. This includes casting to void,
1390 void function calls, and statement expressions with a final cast
1392 if (VOID_TYPE_P (TREE_TYPE (exp)))
1395 if (EXPR_HAS_LOCATION (exp))
1396 locus = EXPR_LOCATION (exp);
1398 switch (TREE_CODE (exp))
1400 case PREINCREMENT_EXPR:
1401 case POSTINCREMENT_EXPR:
1402 case PREDECREMENT_EXPR:
1403 case POSTDECREMENT_EXPR:
1408 case TRY_CATCH_EXPR:
1409 case WITH_CLEANUP_EXPR:
1414 /* For a binding, warn if no side effect within it. */
1415 exp = BIND_EXPR_BODY (exp);
1419 exp = TREE_OPERAND (exp, 0);
1422 case TRUTH_ORIF_EXPR:
1423 case TRUTH_ANDIF_EXPR:
1424 /* In && or ||, warn if 2nd operand has no side effect. */
1425 exp = TREE_OPERAND (exp, 1);
1429 if (TREE_NO_WARNING (exp))
1431 if (warn_if_unused_value (TREE_OPERAND (exp, 0), locus))
1433 /* Let people do `(foo (), 0)' without a warning. */
1434 if (TREE_CONSTANT (TREE_OPERAND (exp, 1)))
1436 exp = TREE_OPERAND (exp, 1);
1441 case NON_LVALUE_EXPR:
1442 /* Don't warn about conversions not explicit in the user's program. */
1443 if (TREE_NO_WARNING (exp))
1445 /* Assignment to a cast usually results in a cast of a modify.
1446 Don't complain about that. There can be an arbitrary number of
1447 casts before the modify, so we must loop until we find the first
1448 non-cast expression and then test to see if that is a modify. */
1450 tree tem = TREE_OPERAND (exp, 0);
1452 while (TREE_CODE (tem) == CONVERT_EXPR || TREE_CODE (tem) == NOP_EXPR)
1453 tem = TREE_OPERAND (tem, 0);
1455 if (TREE_CODE (tem) == MODIFY_EXPR || TREE_CODE (tem) == INIT_EXPR
1456 || TREE_CODE (tem) == CALL_EXPR)
1462 /* Don't warn about automatic dereferencing of references, since
1463 the user cannot control it. */
1464 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (exp, 0))) == REFERENCE_TYPE)
1466 exp = TREE_OPERAND (exp, 0);
1472 /* Referencing a volatile value is a side effect, so don't warn. */
1474 || TREE_CODE_CLASS (TREE_CODE (exp)) == 'r')
1475 && TREE_THIS_VOLATILE (exp))
1478 /* If this is an expression which has no operands, there is no value
1479 to be unused. There are no such language-independent codes,
1480 but front ends may define such. */
1481 if (TREE_CODE_CLASS (TREE_CODE (exp)) == 'e'
1482 && TREE_CODE_LENGTH (TREE_CODE (exp)) == 0)
1486 /* If this is an expression with side effects, don't warn. */
1487 if (TREE_SIDE_EFFECTS (exp))
1490 warning ("%Hvalue computed is not used", &locus);
1495 /* Return nonzero if we should preserve sub-expressions as separate
1496 pseudos. We never do so if we aren't optimizing. We always do so
1497 if -fexpensive-optimizations. */
1500 preserve_subexpressions_p (void)
1502 return optimize && (cfun || flag_expensive_optimizations);
1506 /* Generate RTL to return from the current function, with no value.
1507 (That is, we do not do anything about returning any value.) */
1510 expand_null_return (void)
1512 /* If this function was declared to return a value, but we
1513 didn't, clobber the return registers so that they are not
1514 propagated live to the rest of the function. */
1515 clobber_return_register ();
1517 expand_null_return_1 ();
1520 /* Generate RTL to return directly from the current function.
1521 (That is, we bypass any return value.) */
1524 expand_naked_return (void)
1528 clear_pending_stack_adjust ();
1529 do_pending_stack_adjust ();
1531 end_label = naked_return_label;
1533 end_label = naked_return_label = gen_label_rtx ();
1535 emit_jump (end_label);
1538 /* If the current function returns values in the most significant part
1539 of a register, shift return value VAL appropriately. The mode of
1540 the function's return type is known not to be BLKmode. */
1543 shift_return_value (rtx val)
1547 type = TREE_TYPE (DECL_RESULT (current_function_decl));
1548 if (targetm.calls.return_in_msb (type))
1551 HOST_WIDE_INT shift;
1553 target = DECL_RTL (DECL_RESULT (current_function_decl));
1554 shift = (GET_MODE_BITSIZE (GET_MODE (target))
1555 - BITS_PER_UNIT * int_size_in_bytes (type));
1557 val = expand_shift (LSHIFT_EXPR, GET_MODE (target),
1558 gen_lowpart (GET_MODE (target), val),
1559 build_int_2 (shift, 0), target, 1);
1565 /* Generate RTL to return from the current function, with value VAL. */
1568 expand_value_return (rtx val)
1570 /* Copy the value to the return location
1571 unless it's already there. */
1573 rtx return_reg = DECL_RTL (DECL_RESULT (current_function_decl));
1574 if (return_reg != val)
1576 tree type = TREE_TYPE (DECL_RESULT (current_function_decl));
1577 if (targetm.calls.promote_function_return (TREE_TYPE (current_function_decl)))
1579 int unsignedp = TYPE_UNSIGNED (type);
1580 enum machine_mode old_mode
1581 = DECL_MODE (DECL_RESULT (current_function_decl));
1582 enum machine_mode mode
1583 = promote_mode (type, old_mode, &unsignedp, 1);
1585 if (mode != old_mode)
1586 val = convert_modes (mode, old_mode, val, unsignedp);
1588 if (GET_CODE (return_reg) == PARALLEL)
1589 emit_group_load (return_reg, val, type, int_size_in_bytes (type));
1591 emit_move_insn (return_reg, val);
1594 expand_null_return_1 ();
1597 /* Output a return with no value. */
1600 expand_null_return_1 (void)
1604 clear_pending_stack_adjust ();
1605 do_pending_stack_adjust ();
1607 end_label = return_label;
1609 end_label = return_label = gen_label_rtx ();
1610 emit_jump (end_label);
1613 /* Generate RTL to evaluate the expression RETVAL and return it
1614 from the current function. */
1617 expand_return (tree retval)
1623 /* If function wants no value, give it none. */
1624 if (TREE_CODE (TREE_TYPE (TREE_TYPE (current_function_decl))) == VOID_TYPE)
1626 expand_expr (retval, NULL_RTX, VOIDmode, 0);
1627 expand_null_return ();
1631 if (retval == error_mark_node)
1633 /* Treat this like a return of no value from a function that
1635 expand_null_return ();
1638 else if ((TREE_CODE (retval) == MODIFY_EXPR
1639 || TREE_CODE (retval) == INIT_EXPR)
1640 && TREE_CODE (TREE_OPERAND (retval, 0)) == RESULT_DECL)
1641 retval_rhs = TREE_OPERAND (retval, 1);
1643 retval_rhs = retval;
1645 result_rtl = DECL_RTL (DECL_RESULT (current_function_decl));
1647 /* If we are returning the RESULT_DECL, then the value has already
1648 been stored into it, so we don't have to do anything special. */
1649 if (TREE_CODE (retval_rhs) == RESULT_DECL)
1650 expand_value_return (result_rtl);
1652 /* If the result is an aggregate that is being returned in one (or more)
1653 registers, load the registers here. The compiler currently can't handle
1654 copying a BLKmode value into registers. We could put this code in a
1655 more general area (for use by everyone instead of just function
1656 call/return), but until this feature is generally usable it is kept here
1657 (and in expand_call). */
1659 else if (retval_rhs != 0
1660 && TYPE_MODE (TREE_TYPE (retval_rhs)) == BLKmode
1661 && REG_P (result_rtl))
1664 unsigned HOST_WIDE_INT bitpos, xbitpos;
1665 unsigned HOST_WIDE_INT padding_correction = 0;
1666 unsigned HOST_WIDE_INT bytes
1667 = int_size_in_bytes (TREE_TYPE (retval_rhs));
1668 int n_regs = (bytes + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
1669 unsigned int bitsize
1670 = MIN (TYPE_ALIGN (TREE_TYPE (retval_rhs)), BITS_PER_WORD);
1671 rtx *result_pseudos = alloca (sizeof (rtx) * n_regs);
1672 rtx result_reg, src = NULL_RTX, dst = NULL_RTX;
1673 rtx result_val = expand_expr (retval_rhs, NULL_RTX, VOIDmode, 0);
1674 enum machine_mode tmpmode, result_reg_mode;
1678 expand_null_return ();
1682 /* If the structure doesn't take up a whole number of words, see
1683 whether the register value should be padded on the left or on
1684 the right. Set PADDING_CORRECTION to the number of padding
1685 bits needed on the left side.
1687 In most ABIs, the structure will be returned at the least end of
1688 the register, which translates to right padding on little-endian
1689 targets and left padding on big-endian targets. The opposite
1690 holds if the structure is returned at the most significant
1691 end of the register. */
1692 if (bytes % UNITS_PER_WORD != 0
1693 && (targetm.calls.return_in_msb (TREE_TYPE (retval_rhs))
1695 : BYTES_BIG_ENDIAN))
1696 padding_correction = (BITS_PER_WORD - ((bytes % UNITS_PER_WORD)
1699 /* Copy the structure BITSIZE bits at a time. */
1700 for (bitpos = 0, xbitpos = padding_correction;
1701 bitpos < bytes * BITS_PER_UNIT;
1702 bitpos += bitsize, xbitpos += bitsize)
1704 /* We need a new destination pseudo each time xbitpos is
1705 on a word boundary and when xbitpos == padding_correction
1706 (the first time through). */
1707 if (xbitpos % BITS_PER_WORD == 0
1708 || xbitpos == padding_correction)
1710 /* Generate an appropriate register. */
1711 dst = gen_reg_rtx (word_mode);
1712 result_pseudos[xbitpos / BITS_PER_WORD] = dst;
1714 /* Clear the destination before we move anything into it. */
1715 emit_move_insn (dst, CONST0_RTX (GET_MODE (dst)));
1718 /* We need a new source operand each time bitpos is on a word
1720 if (bitpos % BITS_PER_WORD == 0)
1721 src = operand_subword_force (result_val,
1722 bitpos / BITS_PER_WORD,
1725 /* Use bitpos for the source extraction (left justified) and
1726 xbitpos for the destination store (right justified). */
1727 store_bit_field (dst, bitsize, xbitpos % BITS_PER_WORD, word_mode,
1728 extract_bit_field (src, bitsize,
1729 bitpos % BITS_PER_WORD, 1,
1730 NULL_RTX, word_mode, word_mode));
1733 tmpmode = GET_MODE (result_rtl);
1734 if (tmpmode == BLKmode)
1736 /* Find the smallest integer mode large enough to hold the
1737 entire structure and use that mode instead of BLKmode
1738 on the USE insn for the return register. */
1739 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
1740 tmpmode != VOIDmode;
1741 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
1742 /* Have we found a large enough mode? */
1743 if (GET_MODE_SIZE (tmpmode) >= bytes)
1746 /* No suitable mode found. */
1747 if (tmpmode == VOIDmode)
1750 PUT_MODE (result_rtl, tmpmode);
1753 if (GET_MODE_SIZE (tmpmode) < GET_MODE_SIZE (word_mode))
1754 result_reg_mode = word_mode;
1756 result_reg_mode = tmpmode;
1757 result_reg = gen_reg_rtx (result_reg_mode);
1759 for (i = 0; i < n_regs; i++)
1760 emit_move_insn (operand_subword (result_reg, i, 0, result_reg_mode),
1763 if (tmpmode != result_reg_mode)
1764 result_reg = gen_lowpart (tmpmode, result_reg);
1766 expand_value_return (result_reg);
1768 else if (retval_rhs != 0
1769 && !VOID_TYPE_P (TREE_TYPE (retval_rhs))
1770 && (REG_P (result_rtl)
1771 || (GET_CODE (result_rtl) == PARALLEL)))
1773 /* Calculate the return value into a temporary (usually a pseudo
1775 tree ot = TREE_TYPE (DECL_RESULT (current_function_decl));
1776 tree nt = build_qualified_type (ot, TYPE_QUALS (ot) | TYPE_QUAL_CONST);
1778 val = assign_temp (nt, 0, 0, 1);
1779 val = expand_expr (retval_rhs, val, GET_MODE (val), 0);
1780 val = force_not_mem (val);
1781 /* Return the calculated value. */
1782 expand_value_return (shift_return_value (val));
1786 /* No hard reg used; calculate value into hard return reg. */
1787 expand_expr (retval, const0_rtx, VOIDmode, 0);
1788 expand_value_return (result_rtl);
1792 /* Given a pointer to a BLOCK node return nonzero if (and only if) the node
1793 in question represents the outermost pair of curly braces (i.e. the "body
1794 block") of a function or method.
1796 For any BLOCK node representing a "body block" of a function or method, the
1797 BLOCK_SUPERCONTEXT of the node will point to another BLOCK node which
1798 represents the outermost (function) scope for the function or method (i.e.
1799 the one which includes the formal parameters). The BLOCK_SUPERCONTEXT of
1800 *that* node in turn will point to the relevant FUNCTION_DECL node. */
1803 is_body_block (tree stmt)
1805 if (lang_hooks.no_body_blocks)
1808 if (TREE_CODE (stmt) == BLOCK)
1810 tree parent = BLOCK_SUPERCONTEXT (stmt);
1812 if (parent && TREE_CODE (parent) == BLOCK)
1814 tree grandparent = BLOCK_SUPERCONTEXT (parent);
1816 if (grandparent && TREE_CODE (grandparent) == FUNCTION_DECL)
1824 /* Emit code to restore vital registers at the beginning of a nonlocal goto
1827 expand_nl_goto_receiver (void)
1829 /* Clobber the FP when we get here, so we have to make sure it's
1830 marked as used by this function. */
1831 emit_insn (gen_rtx_USE (VOIDmode, hard_frame_pointer_rtx));
1833 /* Mark the static chain as clobbered here so life information
1834 doesn't get messed up for it. */
1835 emit_insn (gen_rtx_CLOBBER (VOIDmode, static_chain_rtx));
1837 #ifdef HAVE_nonlocal_goto
1838 if (! HAVE_nonlocal_goto)
1840 /* First adjust our frame pointer to its actual value. It was
1841 previously set to the start of the virtual area corresponding to
1842 the stacked variables when we branched here and now needs to be
1843 adjusted to the actual hardware fp value.
1845 Assignments are to virtual registers are converted by
1846 instantiate_virtual_regs into the corresponding assignment
1847 to the underlying register (fp in this case) that makes
1848 the original assignment true.
1849 So the following insn will actually be
1850 decrementing fp by STARTING_FRAME_OFFSET. */
1851 emit_move_insn (virtual_stack_vars_rtx, hard_frame_pointer_rtx);
1853 #if ARG_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
1854 if (fixed_regs[ARG_POINTER_REGNUM])
1856 #ifdef ELIMINABLE_REGS
1857 /* If the argument pointer can be eliminated in favor of the
1858 frame pointer, we don't need to restore it. We assume here
1859 that if such an elimination is present, it can always be used.
1860 This is the case on all known machines; if we don't make this
1861 assumption, we do unnecessary saving on many machines. */
1862 static const struct elims {const int from, to;} elim_regs[] = ELIMINABLE_REGS;
1865 for (i = 0; i < ARRAY_SIZE (elim_regs); i++)
1866 if (elim_regs[i].from == ARG_POINTER_REGNUM
1867 && elim_regs[i].to == HARD_FRAME_POINTER_REGNUM)
1870 if (i == ARRAY_SIZE (elim_regs))
1873 /* Now restore our arg pointer from the address at which it
1874 was saved in our stack frame. */
1875 emit_move_insn (virtual_incoming_args_rtx,
1876 copy_to_reg (get_arg_pointer_save_area (cfun)));
1881 #ifdef HAVE_nonlocal_goto_receiver
1882 if (HAVE_nonlocal_goto_receiver)
1883 emit_insn (gen_nonlocal_goto_receiver ());
1886 /* @@@ This is a kludge. Not all machine descriptions define a blockage
1887 insn, but we must not allow the code we just generated to be reordered
1888 by scheduling. Specifically, the update of the frame pointer must
1889 happen immediately, not later. So emit an ASM_INPUT to act as blockage
1891 emit_insn (gen_rtx_ASM_INPUT (VOIDmode, ""));
1894 /* Generate RTL for the automatic variable declaration DECL.
1895 (Other kinds of declarations are simply ignored if seen here.) */
1898 expand_decl (tree decl)
1902 type = TREE_TYPE (decl);
1904 /* For a CONST_DECL, set mode, alignment, and sizes from those of the
1905 type in case this node is used in a reference. */
1906 if (TREE_CODE (decl) == CONST_DECL)
1908 DECL_MODE (decl) = TYPE_MODE (type);
1909 DECL_ALIGN (decl) = TYPE_ALIGN (type);
1910 DECL_SIZE (decl) = TYPE_SIZE (type);
1911 DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (type);
1915 /* Otherwise, only automatic variables need any expansion done. Static and
1916 external variables, and external functions, will be handled by
1917 `assemble_variable' (called from finish_decl). TYPE_DECL requires
1918 nothing. PARM_DECLs are handled in `assign_parms'. */
1919 if (TREE_CODE (decl) != VAR_DECL)
1922 if (TREE_STATIC (decl) || DECL_EXTERNAL (decl))
1925 /* Create the RTL representation for the variable. */
1927 if (type == error_mark_node)
1928 SET_DECL_RTL (decl, gen_rtx_MEM (BLKmode, const0_rtx));
1930 else if (DECL_SIZE (decl) == 0)
1931 /* Variable with incomplete type. */
1934 if (DECL_INITIAL (decl) == 0)
1935 /* Error message was already done; now avoid a crash. */
1936 x = gen_rtx_MEM (BLKmode, const0_rtx);
1938 /* An initializer is going to decide the size of this array.
1939 Until we know the size, represent its address with a reg. */
1940 x = gen_rtx_MEM (BLKmode, gen_reg_rtx (Pmode));
1942 set_mem_attributes (x, decl, 1);
1943 SET_DECL_RTL (decl, x);
1945 else if (use_register_for_decl (decl))
1947 /* Automatic variable that can go in a register. */
1948 int unsignedp = TYPE_UNSIGNED (type);
1949 enum machine_mode reg_mode
1950 = promote_mode (type, DECL_MODE (decl), &unsignedp, 0);
1952 SET_DECL_RTL (decl, gen_reg_rtx (reg_mode));
1954 /* Note if the object is a user variable. */
1955 if (!DECL_ARTIFICIAL (decl))
1957 mark_user_reg (DECL_RTL (decl));
1959 /* Trust user variables which have a pointer type to really
1960 be pointers. Do not trust compiler generated temporaries
1961 as our type system is totally busted as it relates to
1962 pointer arithmetic which translates into lots of compiler
1963 generated objects with pointer types, but which are not really
1965 if (POINTER_TYPE_P (type))
1966 mark_reg_pointer (DECL_RTL (decl),
1967 TYPE_ALIGN (TREE_TYPE (TREE_TYPE (decl))));
1970 maybe_set_unchanging (DECL_RTL (decl), decl);
1973 else if (TREE_CODE (DECL_SIZE_UNIT (decl)) == INTEGER_CST
1974 && ! (flag_stack_check && ! STACK_CHECK_BUILTIN
1975 && 0 < compare_tree_int (DECL_SIZE_UNIT (decl),
1976 STACK_CHECK_MAX_VAR_SIZE)))
1978 /* Variable of fixed size that goes on the stack. */
1983 /* If we previously made RTL for this decl, it must be an array
1984 whose size was determined by the initializer.
1985 The old address was a register; set that register now
1986 to the proper address. */
1987 if (DECL_RTL_SET_P (decl))
1989 if (!MEM_P (DECL_RTL (decl))
1990 || !REG_P (XEXP (DECL_RTL (decl), 0)))
1992 oldaddr = XEXP (DECL_RTL (decl), 0);
1995 /* Set alignment we actually gave this decl. */
1996 DECL_ALIGN (decl) = (DECL_MODE (decl) == BLKmode ? BIGGEST_ALIGNMENT
1997 : GET_MODE_BITSIZE (DECL_MODE (decl)));
1998 DECL_USER_ALIGN (decl) = 0;
2000 x = assign_temp (decl, 1, 1, 1);
2001 set_mem_attributes (x, decl, 1);
2002 SET_DECL_RTL (decl, x);
2006 addr = force_operand (XEXP (DECL_RTL (decl), 0), oldaddr);
2007 if (addr != oldaddr)
2008 emit_move_insn (oldaddr, addr);
2012 /* Dynamic-size object: must push space on the stack. */
2014 rtx address, size, x;
2016 /* Record the stack pointer on entry to block, if have
2017 not already done so. */
2018 do_pending_stack_adjust ();
2020 /* Compute the variable's size, in bytes. This will expand any
2021 needed SAVE_EXPRs for the first time. */
2022 size = expand_expr (DECL_SIZE_UNIT (decl), NULL_RTX, VOIDmode, 0);
2025 /* Allocate space on the stack for the variable. Note that
2026 DECL_ALIGN says how the variable is to be aligned and we
2027 cannot use it to conclude anything about the alignment of
2029 address = allocate_dynamic_stack_space (size, NULL_RTX,
2030 TYPE_ALIGN (TREE_TYPE (decl)));
2032 /* Reference the variable indirect through that rtx. */
2033 x = gen_rtx_MEM (DECL_MODE (decl), address);
2034 set_mem_attributes (x, decl, 1);
2035 SET_DECL_RTL (decl, x);
2038 /* Indicate the alignment we actually gave this variable. */
2039 #ifdef STACK_BOUNDARY
2040 DECL_ALIGN (decl) = STACK_BOUNDARY;
2042 DECL_ALIGN (decl) = BIGGEST_ALIGNMENT;
2044 DECL_USER_ALIGN (decl) = 0;
2048 /* Emit code to save the current value of stack. */
2050 expand_stack_save (void)
2054 do_pending_stack_adjust ();
2055 emit_stack_save (SAVE_BLOCK, &ret, NULL_RTX);
2059 /* Emit code to restore the current value of stack. */
2061 expand_stack_restore (tree var)
2063 rtx sa = DECL_RTL (var);
2065 emit_stack_restore (SAVE_BLOCK, sa, NULL_RTX);
2068 /* Emit code to perform the initialization of a declaration DECL. */
2071 expand_decl_init (tree decl)
2073 int was_used = TREE_USED (decl);
2075 /* If this is a CONST_DECL, we don't have to generate any code. Likewise
2076 for static decls. */
2077 if (TREE_CODE (decl) == CONST_DECL
2078 || TREE_STATIC (decl))
2081 /* Compute and store the initial value now. */
2085 if (DECL_INITIAL (decl) == error_mark_node)
2087 enum tree_code code = TREE_CODE (TREE_TYPE (decl));
2089 if (code == INTEGER_TYPE || code == REAL_TYPE || code == ENUMERAL_TYPE
2090 || code == POINTER_TYPE || code == REFERENCE_TYPE)
2091 expand_assignment (decl, convert (TREE_TYPE (decl), integer_zero_node),
2094 else if (DECL_INITIAL (decl) && TREE_CODE (DECL_INITIAL (decl)) != TREE_LIST)
2096 emit_line_note (DECL_SOURCE_LOCATION (decl));
2097 expand_assignment (decl, DECL_INITIAL (decl), 0);
2100 /* Don't let the initialization count as "using" the variable. */
2101 TREE_USED (decl) = was_used;
2103 /* Free any temporaries we made while initializing the decl. */
2104 preserve_temp_slots (NULL_RTX);
2110 /* DECL is an anonymous union. CLEANUP is a cleanup for DECL.
2111 DECL_ELTS is the list of elements that belong to DECL's type.
2112 In each, the TREE_VALUE is a VAR_DECL, and the TREE_PURPOSE a cleanup. */
2115 expand_anon_union_decl (tree decl, tree cleanup ATTRIBUTE_UNUSED,
2121 /* If any of the elements are addressable, so is the entire union. */
2122 for (t = decl_elts; t; t = TREE_CHAIN (t))
2123 if (TREE_ADDRESSABLE (TREE_VALUE (t)))
2125 TREE_ADDRESSABLE (decl) = 1;
2130 x = DECL_RTL (decl);
2132 /* Go through the elements, assigning RTL to each. */
2133 for (t = decl_elts; t; t = TREE_CHAIN (t))
2135 tree decl_elt = TREE_VALUE (t);
2136 enum machine_mode mode = TYPE_MODE (TREE_TYPE (decl_elt));
2138 /* If any of the elements are addressable, so is the entire
2140 if (TREE_USED (decl_elt))
2141 TREE_USED (decl) = 1;
2143 /* Propagate the union's alignment to the elements. */
2144 DECL_ALIGN (decl_elt) = DECL_ALIGN (decl);
2145 DECL_USER_ALIGN (decl_elt) = DECL_USER_ALIGN (decl);
2147 /* If the element has BLKmode and the union doesn't, the union is
2148 aligned such that the element doesn't need to have BLKmode, so
2149 change the element's mode to the appropriate one for its size. */
2150 if (mode == BLKmode && DECL_MODE (decl) != BLKmode)
2151 DECL_MODE (decl_elt) = mode
2152 = mode_for_size_tree (DECL_SIZE (decl_elt), MODE_INT, 1);
2154 /* (SUBREG (MEM ...)) at RTL generation time is invalid, so we
2155 instead create a new MEM rtx with the proper mode. */
2158 if (mode == GET_MODE (x))
2159 SET_DECL_RTL (decl_elt, x);
2161 SET_DECL_RTL (decl_elt, adjust_address_nv (x, mode, 0));
2165 if (mode == GET_MODE (x))
2166 SET_DECL_RTL (decl_elt, x);
2168 SET_DECL_RTL (decl_elt, gen_lowpart_SUBREG (mode, x));
2175 /* Do the insertion of a case label into case_list. The labels are
2176 fed to us in descending order from the sorted vector of case labels used
2177 in the tree part of the middle end. So the list we construct is
2178 sorted in ascending order. */
2181 add_case_node (struct case_node *head, tree low, tree high, tree label)
2183 struct case_node *r;
2185 /* If there's no HIGH value, then this is not a case range; it's
2186 just a simple case label. But that's just a degenerate case
2188 If the bounds are equal, turn this into the one-value case. */
2189 if (!high || tree_int_cst_equal (low, high))
2192 /* Add this label to the chain. */
2193 r = ggc_alloc (sizeof (struct case_node));
2196 r->code_label = label;
2197 r->parent = r->left = NULL;
2202 /* Maximum number of case bit tests. */
2203 #define MAX_CASE_BIT_TESTS 3
2205 /* By default, enable case bit tests on targets with ashlsi3. */
2206 #ifndef CASE_USE_BIT_TESTS
2207 #define CASE_USE_BIT_TESTS (ashl_optab->handlers[word_mode].insn_code \
2208 != CODE_FOR_nothing)
2212 /* A case_bit_test represents a set of case nodes that may be
2213 selected from using a bit-wise comparison. HI and LO hold
2214 the integer to be tested against, LABEL contains the label
2215 to jump to upon success and BITS counts the number of case
2216 nodes handled by this test, typically the number of bits
2219 struct case_bit_test
2227 /* Determine whether "1 << x" is relatively cheap in word_mode. */
2230 bool lshift_cheap_p (void)
2232 static bool init = false;
2233 static bool cheap = true;
2237 rtx reg = gen_rtx_REG (word_mode, 10000);
2238 int cost = rtx_cost (gen_rtx_ASHIFT (word_mode, const1_rtx, reg), SET);
2239 cheap = cost < COSTS_N_INSNS (3);
2246 /* Comparison function for qsort to order bit tests by decreasing
2247 number of case nodes, i.e. the node with the most cases gets
2251 case_bit_test_cmp (const void *p1, const void *p2)
2253 const struct case_bit_test *d1 = p1;
2254 const struct case_bit_test *d2 = p2;
2256 return d2->bits - d1->bits;
2259 /* Expand a switch statement by a short sequence of bit-wise
2260 comparisons. "switch(x)" is effectively converted into
2261 "if ((1 << (x-MINVAL)) & CST)" where CST and MINVAL are
2264 INDEX_EXPR is the value being switched on, which is of
2265 type INDEX_TYPE. MINVAL is the lowest case value of in
2266 the case nodes, of INDEX_TYPE type, and RANGE is highest
2267 value minus MINVAL, also of type INDEX_TYPE. NODES is
2268 the set of case nodes, and DEFAULT_LABEL is the label to
2269 branch to should none of the cases match.
2271 There *MUST* be MAX_CASE_BIT_TESTS or less unique case
2275 emit_case_bit_tests (tree index_type, tree index_expr, tree minval,
2276 tree range, case_node_ptr nodes, rtx default_label)
2278 struct case_bit_test test[MAX_CASE_BIT_TESTS];
2279 enum machine_mode mode;
2280 rtx expr, index, label;
2281 unsigned int i,j,lo,hi;
2282 struct case_node *n;
2286 for (n = nodes; n; n = n->right)
2288 label = label_rtx (n->code_label);
2289 for (i = 0; i < count; i++)
2290 if (label == test[i].label)
2295 if (count >= MAX_CASE_BIT_TESTS)
2299 test[i].label = label;
2306 lo = tree_low_cst (fold (build2 (MINUS_EXPR, index_type,
2307 n->low, minval)), 1);
2308 hi = tree_low_cst (fold (build2 (MINUS_EXPR, index_type,
2309 n->high, minval)), 1);
2310 for (j = lo; j <= hi; j++)
2311 if (j >= HOST_BITS_PER_WIDE_INT)
2312 test[i].hi |= (HOST_WIDE_INT) 1 << (j - HOST_BITS_PER_INT);
2314 test[i].lo |= (HOST_WIDE_INT) 1 << j;
2317 qsort (test, count, sizeof(*test), case_bit_test_cmp);
2319 index_expr = fold (build2 (MINUS_EXPR, index_type,
2320 convert (index_type, index_expr),
2321 convert (index_type, minval)));
2322 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
2323 do_pending_stack_adjust ();
2325 mode = TYPE_MODE (index_type);
2326 expr = expand_expr (range, NULL_RTX, VOIDmode, 0);
2327 emit_cmp_and_jump_insns (index, expr, GTU, NULL_RTX, mode, 1,
2330 index = convert_to_mode (word_mode, index, 0);
2331 index = expand_binop (word_mode, ashl_optab, const1_rtx,
2332 index, NULL_RTX, 1, OPTAB_WIDEN);
2334 for (i = 0; i < count; i++)
2336 expr = immed_double_const (test[i].lo, test[i].hi, word_mode);
2337 expr = expand_binop (word_mode, and_optab, index, expr,
2338 NULL_RTX, 1, OPTAB_WIDEN);
2339 emit_cmp_and_jump_insns (expr, const0_rtx, NE, NULL_RTX,
2340 word_mode, 1, test[i].label);
2343 emit_jump (default_label);
2347 #define HAVE_casesi 0
2350 #ifndef HAVE_tablejump
2351 #define HAVE_tablejump 0
2354 /* Terminate a case (Pascal) or switch (C) statement
2355 in which ORIG_INDEX is the expression to be tested.
2356 If ORIG_TYPE is not NULL, it is the original ORIG_INDEX
2357 type as given in the source before any compiler conversions.
2358 Generate the code to test it and jump to the right place. */
2361 expand_case (tree exp)
2363 tree minval = NULL_TREE, maxval = NULL_TREE, range = NULL_TREE;
2364 rtx default_label = 0;
2365 struct case_node *n, *m;
2366 unsigned int count, uniq;
2372 rtx before_case, end, lab;
2374 tree vec = SWITCH_LABELS (exp);
2375 tree orig_type = TREE_TYPE (exp);
2376 tree index_expr = SWITCH_COND (exp);
2377 tree index_type = TREE_TYPE (index_expr);
2378 int unsignedp = TYPE_UNSIGNED (index_type);
2380 /* The insn after which the case dispatch should finally
2381 be emitted. Zero for a dummy. */
2384 /* A list of case labels; it is first built as a list and it may then
2385 be rearranged into a nearly balanced binary tree. */
2386 struct case_node *case_list = 0;
2388 /* Label to jump to if no case matches. */
2389 tree default_label_decl = 0;
2391 /* The switch body is lowered in gimplify.c, we should never have
2392 switches with a non-NULL SWITCH_BODY here. */
2393 if (SWITCH_BODY (exp) || !SWITCH_LABELS (exp))
2396 for (i = TREE_VEC_LENGTH (vec); --i >= 0; )
2398 tree elt = TREE_VEC_ELT (vec, i);
2400 /* Handle default labels specially. */
2401 if (!CASE_HIGH (elt) && !CASE_LOW (elt))
2403 #ifdef ENABLE_CHECKING
2404 if (default_label_decl != 0)
2407 default_label_decl = CASE_LABEL (elt);
2410 case_list = add_case_node (case_list, CASE_LOW (elt), CASE_HIGH (elt),
2414 do_pending_stack_adjust ();
2416 /* Make sure start points to something that won't need any transformation
2417 before the end of this function. */
2418 if (!NOTE_P (get_last_insn ()))
2419 emit_note (NOTE_INSN_DELETED);
2421 start = get_last_insn ();
2423 /* An ERROR_MARK occurs for various reasons including invalid data type. */
2424 if (index_type != error_mark_node)
2426 /* If we don't have a default-label, create one here,
2427 after the body of the switch. */
2428 if (default_label_decl == 0)
2431 = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
2432 expand_label (default_label_decl);
2434 default_label = label_rtx (default_label_decl);
2436 before_case = get_last_insn ();
2438 /* Get upper and lower bounds of case values.
2439 Also convert all the case values to the index expr's data type. */
2443 for (n = case_list; n; n = n->right)
2445 /* Check low and high label values are integers. */
2446 if (TREE_CODE (n->low) != INTEGER_CST)
2448 if (TREE_CODE (n->high) != INTEGER_CST)
2451 n->low = convert (index_type, n->low);
2452 n->high = convert (index_type, n->high);
2454 /* Count the elements and track the largest and smallest
2455 of them (treating them as signed even if they are not). */
2463 if (INT_CST_LT (n->low, minval))
2465 if (INT_CST_LT (maxval, n->high))
2468 /* A range counts double, since it requires two compares. */
2469 if (! tree_int_cst_equal (n->low, n->high))
2472 /* Count the number of unique case node targets. */
2474 lab = label_rtx (n->code_label);
2475 for (m = case_list; m != n; m = m->right)
2476 if (label_rtx (m->code_label) == lab)
2483 /* Compute span of values. */
2485 range = fold (build2 (MINUS_EXPR, index_type, maxval, minval));
2489 expand_expr (index_expr, const0_rtx, VOIDmode, 0);
2490 emit_jump (default_label);
2493 /* Try implementing this switch statement by a short sequence of
2494 bit-wise comparisons. However, we let the binary-tree case
2495 below handle constant index expressions. */
2496 else if (CASE_USE_BIT_TESTS
2497 && ! TREE_CONSTANT (index_expr)
2498 && compare_tree_int (range, GET_MODE_BITSIZE (word_mode)) < 0
2499 && compare_tree_int (range, 0) > 0
2500 && lshift_cheap_p ()
2501 && ((uniq == 1 && count >= 3)
2502 || (uniq == 2 && count >= 5)
2503 || (uniq == 3 && count >= 6)))
2505 /* Optimize the case where all the case values fit in a
2506 word without having to subtract MINVAL. In this case,
2507 we can optimize away the subtraction. */
2508 if (compare_tree_int (minval, 0) > 0
2509 && compare_tree_int (maxval, GET_MODE_BITSIZE (word_mode)) < 0)
2511 minval = integer_zero_node;
2514 emit_case_bit_tests (index_type, index_expr, minval, range,
2515 case_list, default_label);
2518 /* If range of values is much bigger than number of values,
2519 make a sequence of conditional branches instead of a dispatch.
2520 If the switch-index is a constant, do it this way
2521 because we can optimize it. */
2523 else if (count < case_values_threshold ()
2524 || compare_tree_int (range,
2525 (optimize_size ? 3 : 10) * count) > 0
2526 /* RANGE may be signed, and really large ranges will show up
2527 as negative numbers. */
2528 || compare_tree_int (range, 0) < 0
2529 #ifndef ASM_OUTPUT_ADDR_DIFF_ELT
2532 || TREE_CONSTANT (index_expr)
2533 /* If neither casesi or tablejump is available, we can
2534 only go this way. */
2535 || (!HAVE_casesi && !HAVE_tablejump))
2537 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
2539 /* If the index is a short or char that we do not have
2540 an insn to handle comparisons directly, convert it to
2541 a full integer now, rather than letting each comparison
2542 generate the conversion. */
2544 if (GET_MODE_CLASS (GET_MODE (index)) == MODE_INT
2545 && ! have_insn_for (COMPARE, GET_MODE (index)))
2547 enum machine_mode wider_mode;
2548 for (wider_mode = GET_MODE (index); wider_mode != VOIDmode;
2549 wider_mode = GET_MODE_WIDER_MODE (wider_mode))
2550 if (have_insn_for (COMPARE, wider_mode))
2552 index = convert_to_mode (wider_mode, index, unsignedp);
2557 do_pending_stack_adjust ();
2560 index = copy_to_reg (index);
2561 if (GET_CODE (index) == CONST_INT
2562 || TREE_CODE (index_expr) == INTEGER_CST)
2564 /* Make a tree node with the proper constant value
2565 if we don't already have one. */
2566 if (TREE_CODE (index_expr) != INTEGER_CST)
2569 = build_int_2 (INTVAL (index),
2570 unsignedp || INTVAL (index) >= 0 ? 0 : -1);
2571 index_expr = convert (index_type, index_expr);
2574 /* For constant index expressions we need only
2575 issue an unconditional branch to the appropriate
2576 target code. The job of removing any unreachable
2577 code is left to the optimization phase if the
2578 "-O" option is specified. */
2579 for (n = case_list; n; n = n->right)
2580 if (! tree_int_cst_lt (index_expr, n->low)
2581 && ! tree_int_cst_lt (n->high, index_expr))
2585 emit_jump (label_rtx (n->code_label));
2587 emit_jump (default_label);
2591 /* If the index expression is not constant we generate
2592 a binary decision tree to select the appropriate
2593 target code. This is done as follows:
2595 The list of cases is rearranged into a binary tree,
2596 nearly optimal assuming equal probability for each case.
2598 The tree is transformed into RTL, eliminating
2599 redundant test conditions at the same time.
2601 If program flow could reach the end of the
2602 decision tree an unconditional jump to the
2603 default code is emitted. */
2606 = (TREE_CODE (orig_type) != ENUMERAL_TYPE
2607 && estimate_case_costs (case_list));
2608 balance_case_nodes (&case_list, NULL);
2609 emit_case_nodes (index, case_list, default_label, index_type);
2610 emit_jump (default_label);
2615 table_label = gen_label_rtx ();
2616 if (! try_casesi (index_type, index_expr, minval, range,
2617 table_label, default_label))
2619 index_type = integer_type_node;
2621 /* Index jumptables from zero for suitable values of
2622 minval to avoid a subtraction. */
2624 && compare_tree_int (minval, 0) > 0
2625 && compare_tree_int (minval, 3) < 0)
2627 minval = integer_zero_node;
2631 if (! try_tablejump (index_type, index_expr, minval, range,
2632 table_label, default_label))
2636 /* Get table of labels to jump to, in order of case index. */
2638 ncases = tree_low_cst (range, 0) + 1;
2639 labelvec = alloca (ncases * sizeof (rtx));
2640 memset (labelvec, 0, ncases * sizeof (rtx));
2642 for (n = case_list; n; n = n->right)
2644 /* Compute the low and high bounds relative to the minimum
2645 value since that should fit in a HOST_WIDE_INT while the
2646 actual values may not. */
2648 = tree_low_cst (fold (build2 (MINUS_EXPR, index_type,
2649 n->low, minval)), 1);
2650 HOST_WIDE_INT i_high
2651 = tree_low_cst (fold (build2 (MINUS_EXPR, index_type,
2652 n->high, minval)), 1);
2655 for (i = i_low; i <= i_high; i ++)
2657 = gen_rtx_LABEL_REF (Pmode, label_rtx (n->code_label));
2660 /* Fill in the gaps with the default. */
2661 for (i = 0; i < ncases; i++)
2662 if (labelvec[i] == 0)
2663 labelvec[i] = gen_rtx_LABEL_REF (Pmode, default_label);
2665 /* Output the table. */
2666 emit_label (table_label);
2668 if (CASE_VECTOR_PC_RELATIVE || flag_pic)
2669 emit_jump_insn (gen_rtx_ADDR_DIFF_VEC (CASE_VECTOR_MODE,
2670 gen_rtx_LABEL_REF (Pmode, table_label),
2671 gen_rtvec_v (ncases, labelvec),
2672 const0_rtx, const0_rtx));
2674 emit_jump_insn (gen_rtx_ADDR_VEC (CASE_VECTOR_MODE,
2675 gen_rtvec_v (ncases, labelvec)));
2677 /* If the case insn drops through the table,
2678 after the table we must jump to the default-label.
2679 Otherwise record no drop-through after the table. */
2680 #ifdef CASE_DROPS_THROUGH
2681 emit_jump (default_label);
2687 before_case = NEXT_INSN (before_case);
2688 end = get_last_insn ();
2689 if (squeeze_notes (&before_case, &end))
2691 reorder_insns (before_case, end, start);
2697 /* Generate code to jump to LABEL if OP1 and OP2 are equal. */
2700 do_jump_if_equal (rtx op1, rtx op2, rtx label, int unsignedp)
2702 if (GET_CODE (op1) == CONST_INT && GET_CODE (op2) == CONST_INT)
2708 emit_cmp_and_jump_insns (op1, op2, EQ, NULL_RTX,
2709 (GET_MODE (op1) == VOIDmode
2710 ? GET_MODE (op2) : GET_MODE (op1)),
2714 /* Not all case values are encountered equally. This function
2715 uses a heuristic to weight case labels, in cases where that
2716 looks like a reasonable thing to do.
2718 Right now, all we try to guess is text, and we establish the
2721 chars above space: 16
2730 If we find any cases in the switch that are not either -1 or in the range
2731 of valid ASCII characters, or are control characters other than those
2732 commonly used with "\", don't treat this switch scanning text.
2734 Return 1 if these nodes are suitable for cost estimation, otherwise
2738 estimate_case_costs (case_node_ptr node)
2740 tree min_ascii = integer_minus_one_node;
2741 tree max_ascii = convert (TREE_TYPE (node->high), build_int_2 (127, 0));
2745 /* If we haven't already made the cost table, make it now. Note that the
2746 lower bound of the table is -1, not zero. */
2748 if (! cost_table_initialized)
2750 cost_table_initialized = 1;
2752 for (i = 0; i < 128; i++)
2755 COST_TABLE (i) = 16;
2756 else if (ISPUNCT (i))
2758 else if (ISCNTRL (i))
2759 COST_TABLE (i) = -1;
2762 COST_TABLE (' ') = 8;
2763 COST_TABLE ('\t') = 4;
2764 COST_TABLE ('\0') = 4;
2765 COST_TABLE ('\n') = 2;
2766 COST_TABLE ('\f') = 1;
2767 COST_TABLE ('\v') = 1;
2768 COST_TABLE ('\b') = 1;
2771 /* See if all the case expressions look like text. It is text if the
2772 constant is >= -1 and the highest constant is <= 127. Do all comparisons
2773 as signed arithmetic since we don't want to ever access cost_table with a
2774 value less than -1. Also check that none of the constants in a range
2775 are strange control characters. */
2777 for (n = node; n; n = n->right)
2779 if ((INT_CST_LT (n->low, min_ascii)) || INT_CST_LT (max_ascii, n->high))
2782 for (i = (HOST_WIDE_INT) TREE_INT_CST_LOW (n->low);
2783 i <= (HOST_WIDE_INT) TREE_INT_CST_LOW (n->high); i++)
2784 if (COST_TABLE (i) < 0)
2788 /* All interesting values are within the range of interesting
2789 ASCII characters. */
2793 /* Take an ordered list of case nodes
2794 and transform them into a near optimal binary tree,
2795 on the assumption that any target code selection value is as
2796 likely as any other.
2798 The transformation is performed by splitting the ordered
2799 list into two equal sections plus a pivot. The parts are
2800 then attached to the pivot as left and right branches. Each
2801 branch is then transformed recursively. */
2804 balance_case_nodes (case_node_ptr *head, case_node_ptr parent)
2817 /* Count the number of entries on branch. Also count the ranges. */
2821 if (!tree_int_cst_equal (np->low, np->high))
2825 cost += COST_TABLE (TREE_INT_CST_LOW (np->high));
2829 cost += COST_TABLE (TREE_INT_CST_LOW (np->low));
2837 /* Split this list if it is long enough for that to help. */
2842 /* Find the place in the list that bisects the list's total cost,
2843 Here I gets half the total cost. */
2848 /* Skip nodes while their cost does not reach that amount. */
2849 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
2850 i -= COST_TABLE (TREE_INT_CST_LOW ((*npp)->high));
2851 i -= COST_TABLE (TREE_INT_CST_LOW ((*npp)->low));
2854 npp = &(*npp)->right;
2859 /* Leave this branch lopsided, but optimize left-hand
2860 side and fill in `parent' fields for right-hand side. */
2862 np->parent = parent;
2863 balance_case_nodes (&np->left, np);
2864 for (; np->right; np = np->right)
2865 np->right->parent = np;
2869 /* If there are just three nodes, split at the middle one. */
2871 npp = &(*npp)->right;
2874 /* Find the place in the list that bisects the list's total cost,
2875 where ranges count as 2.
2876 Here I gets half the total cost. */
2877 i = (i + ranges + 1) / 2;
2880 /* Skip nodes while their cost does not reach that amount. */
2881 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
2886 npp = &(*npp)->right;
2891 np->parent = parent;
2894 /* Optimize each of the two split parts. */
2895 balance_case_nodes (&np->left, np);
2896 balance_case_nodes (&np->right, np);
2900 /* Else leave this branch as one level,
2901 but fill in `parent' fields. */
2903 np->parent = parent;
2904 for (; np->right; np = np->right)
2905 np->right->parent = np;
2910 /* Search the parent sections of the case node tree
2911 to see if a test for the lower bound of NODE would be redundant.
2912 INDEX_TYPE is the type of the index expression.
2914 The instructions to generate the case decision tree are
2915 output in the same order as nodes are processed so it is
2916 known that if a parent node checks the range of the current
2917 node minus one that the current node is bounded at its lower
2918 span. Thus the test would be redundant. */
2921 node_has_low_bound (case_node_ptr node, tree index_type)
2924 case_node_ptr pnode;
2926 /* If the lower bound of this node is the lowest value in the index type,
2927 we need not test it. */
2929 if (tree_int_cst_equal (node->low, TYPE_MIN_VALUE (index_type)))
2932 /* If this node has a left branch, the value at the left must be less
2933 than that at this node, so it cannot be bounded at the bottom and
2934 we need not bother testing any further. */
2939 low_minus_one = fold (build2 (MINUS_EXPR, TREE_TYPE (node->low),
2940 node->low, integer_one_node));
2942 /* If the subtraction above overflowed, we can't verify anything.
2943 Otherwise, look for a parent that tests our value - 1. */
2945 if (! tree_int_cst_lt (low_minus_one, node->low))
2948 for (pnode = node->parent; pnode; pnode = pnode->parent)
2949 if (tree_int_cst_equal (low_minus_one, pnode->high))
2955 /* Search the parent sections of the case node tree
2956 to see if a test for the upper bound of NODE would be redundant.
2957 INDEX_TYPE is the type of the index expression.
2959 The instructions to generate the case decision tree are
2960 output in the same order as nodes are processed so it is
2961 known that if a parent node checks the range of the current
2962 node plus one that the current node is bounded at its upper
2963 span. Thus the test would be redundant. */
2966 node_has_high_bound (case_node_ptr node, tree index_type)
2969 case_node_ptr pnode;
2971 /* If there is no upper bound, obviously no test is needed. */
2973 if (TYPE_MAX_VALUE (index_type) == NULL)
2976 /* If the upper bound of this node is the highest value in the type
2977 of the index expression, we need not test against it. */
2979 if (tree_int_cst_equal (node->high, TYPE_MAX_VALUE (index_type)))
2982 /* If this node has a right branch, the value at the right must be greater
2983 than that at this node, so it cannot be bounded at the top and
2984 we need not bother testing any further. */
2989 high_plus_one = fold (build2 (PLUS_EXPR, TREE_TYPE (node->high),
2990 node->high, integer_one_node));
2992 /* If the addition above overflowed, we can't verify anything.
2993 Otherwise, look for a parent that tests our value + 1. */
2995 if (! tree_int_cst_lt (node->high, high_plus_one))
2998 for (pnode = node->parent; pnode; pnode = pnode->parent)
2999 if (tree_int_cst_equal (high_plus_one, pnode->low))
3005 /* Search the parent sections of the
3006 case node tree to see if both tests for the upper and lower
3007 bounds of NODE would be redundant. */
3010 node_is_bounded (case_node_ptr node, tree index_type)
3012 return (node_has_low_bound (node, index_type)
3013 && node_has_high_bound (node, index_type));
3016 /* Emit step-by-step code to select a case for the value of INDEX.
3017 The thus generated decision tree follows the form of the
3018 case-node binary tree NODE, whose nodes represent test conditions.
3019 INDEX_TYPE is the type of the index of the switch.
3021 Care is taken to prune redundant tests from the decision tree
3022 by detecting any boundary conditions already checked by
3023 emitted rtx. (See node_has_high_bound, node_has_low_bound
3024 and node_is_bounded, above.)
3026 Where the test conditions can be shown to be redundant we emit
3027 an unconditional jump to the target code. As a further
3028 optimization, the subordinates of a tree node are examined to
3029 check for bounded nodes. In this case conditional and/or
3030 unconditional jumps as a result of the boundary check for the
3031 current node are arranged to target the subordinates associated
3032 code for out of bound conditions on the current node.
3034 We can assume that when control reaches the code generated here,
3035 the index value has already been compared with the parents
3036 of this node, and determined to be on the same side of each parent
3037 as this node is. Thus, if this node tests for the value 51,
3038 and a parent tested for 52, we don't need to consider
3039 the possibility of a value greater than 51. If another parent
3040 tests for the value 50, then this node need not test anything. */
3043 emit_case_nodes (rtx index, case_node_ptr node, rtx default_label,
3046 /* If INDEX has an unsigned type, we must make unsigned branches. */
3047 int unsignedp = TYPE_UNSIGNED (index_type);
3048 enum machine_mode mode = GET_MODE (index);
3049 enum machine_mode imode = TYPE_MODE (index_type);
3051 /* See if our parents have already tested everything for us.
3052 If they have, emit an unconditional jump for this node. */
3053 if (node_is_bounded (node, index_type))
3054 emit_jump (label_rtx (node->code_label));
3056 else if (tree_int_cst_equal (node->low, node->high))
3058 /* Node is single valued. First see if the index expression matches
3059 this node and then check our children, if any. */
3061 do_jump_if_equal (index,
3062 convert_modes (mode, imode,
3063 expand_expr (node->low, NULL_RTX,
3066 label_rtx (node->code_label), unsignedp);
3068 if (node->right != 0 && node->left != 0)
3070 /* This node has children on both sides.
3071 Dispatch to one side or the other
3072 by comparing the index value with this node's value.
3073 If one subtree is bounded, check that one first,
3074 so we can avoid real branches in the tree. */
3076 if (node_is_bounded (node->right, index_type))
3078 emit_cmp_and_jump_insns (index,
3081 expand_expr (node->high, NULL_RTX,
3084 GT, NULL_RTX, mode, unsignedp,
3085 label_rtx (node->right->code_label));
3086 emit_case_nodes (index, node->left, default_label, index_type);
3089 else if (node_is_bounded (node->left, index_type))
3091 emit_cmp_and_jump_insns (index,
3094 expand_expr (node->high, NULL_RTX,
3097 LT, NULL_RTX, mode, unsignedp,
3098 label_rtx (node->left->code_label));
3099 emit_case_nodes (index, node->right, default_label, index_type);
3102 /* If both children are single-valued cases with no
3103 children, finish up all the work. This way, we can save
3104 one ordered comparison. */
3105 else if (tree_int_cst_equal (node->right->low, node->right->high)
3106 && node->right->left == 0
3107 && node->right->right == 0
3108 && tree_int_cst_equal (node->left->low, node->left->high)
3109 && node->left->left == 0
3110 && node->left->right == 0)
3112 /* Neither node is bounded. First distinguish the two sides;
3113 then emit the code for one side at a time. */
3115 /* See if the value matches what the right hand side
3117 do_jump_if_equal (index,
3118 convert_modes (mode, imode,
3119 expand_expr (node->right->low,
3123 label_rtx (node->right->code_label),
3126 /* See if the value matches what the left hand side
3128 do_jump_if_equal (index,
3129 convert_modes (mode, imode,
3130 expand_expr (node->left->low,
3134 label_rtx (node->left->code_label),
3140 /* Neither node is bounded. First distinguish the two sides;
3141 then emit the code for one side at a time. */
3143 tree test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
3145 /* See if the value is on the right. */
3146 emit_cmp_and_jump_insns (index,
3149 expand_expr (node->high, NULL_RTX,
3152 GT, NULL_RTX, mode, unsignedp,
3153 label_rtx (test_label));
3155 /* Value must be on the left.
3156 Handle the left-hand subtree. */
3157 emit_case_nodes (index, node->left, default_label, index_type);
3158 /* If left-hand subtree does nothing,
3160 emit_jump (default_label);
3162 /* Code branches here for the right-hand subtree. */
3163 expand_label (test_label);
3164 emit_case_nodes (index, node->right, default_label, index_type);
3168 else if (node->right != 0 && node->left == 0)
3170 /* Here we have a right child but no left so we issue conditional
3171 branch to default and process the right child.
3173 Omit the conditional branch to default if we it avoid only one
3174 right child; it costs too much space to save so little time. */
3176 if (node->right->right || node->right->left
3177 || !tree_int_cst_equal (node->right->low, node->right->high))
3179 if (!node_has_low_bound (node, index_type))
3181 emit_cmp_and_jump_insns (index,
3184 expand_expr (node->high, NULL_RTX,
3187 LT, NULL_RTX, mode, unsignedp,
3191 emit_case_nodes (index, node->right, default_label, index_type);
3194 /* We cannot process node->right normally
3195 since we haven't ruled out the numbers less than
3196 this node's value. So handle node->right explicitly. */
3197 do_jump_if_equal (index,
3200 expand_expr (node->right->low, NULL_RTX,
3203 label_rtx (node->right->code_label), unsignedp);
3206 else if (node->right == 0 && node->left != 0)
3208 /* Just one subtree, on the left. */
3209 if (node->left->left || node->left->right
3210 || !tree_int_cst_equal (node->left->low, node->left->high))
3212 if (!node_has_high_bound (node, index_type))
3214 emit_cmp_and_jump_insns (index,
3217 expand_expr (node->high, NULL_RTX,
3220 GT, NULL_RTX, mode, unsignedp,
3224 emit_case_nodes (index, node->left, default_label, index_type);
3227 /* We cannot process node->left normally
3228 since we haven't ruled out the numbers less than
3229 this node's value. So handle node->left explicitly. */
3230 do_jump_if_equal (index,
3233 expand_expr (node->left->low, NULL_RTX,
3236 label_rtx (node->left->code_label), unsignedp);
3241 /* Node is a range. These cases are very similar to those for a single
3242 value, except that we do not start by testing whether this node
3243 is the one to branch to. */
3245 if (node->right != 0 && node->left != 0)
3247 /* Node has subtrees on both sides.
3248 If the right-hand subtree is bounded,
3249 test for it first, since we can go straight there.
3250 Otherwise, we need to make a branch in the control structure,
3251 then handle the two subtrees. */
3252 tree test_label = 0;
3254 if (node_is_bounded (node->right, index_type))
3255 /* Right hand node is fully bounded so we can eliminate any
3256 testing and branch directly to the target code. */
3257 emit_cmp_and_jump_insns (index,
3260 expand_expr (node->high, NULL_RTX,
3263 GT, NULL_RTX, mode, unsignedp,
3264 label_rtx (node->right->code_label));
3267 /* Right hand node requires testing.
3268 Branch to a label where we will handle it later. */
3270 test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
3271 emit_cmp_and_jump_insns (index,
3274 expand_expr (node->high, NULL_RTX,
3277 GT, NULL_RTX, mode, unsignedp,
3278 label_rtx (test_label));
3281 /* Value belongs to this node or to the left-hand subtree. */
3283 emit_cmp_and_jump_insns (index,
3286 expand_expr (node->low, NULL_RTX,
3289 GE, NULL_RTX, mode, unsignedp,
3290 label_rtx (node->code_label));
3292 /* Handle the left-hand subtree. */
3293 emit_case_nodes (index, node->left, default_label, index_type);
3295 /* If right node had to be handled later, do that now. */
3299 /* If the left-hand subtree fell through,
3300 don't let it fall into the right-hand subtree. */
3301 emit_jump (default_label);
3303 expand_label (test_label);
3304 emit_case_nodes (index, node->right, default_label, index_type);
3308 else if (node->right != 0 && node->left == 0)
3310 /* Deal with values to the left of this node,
3311 if they are possible. */
3312 if (!node_has_low_bound (node, index_type))
3314 emit_cmp_and_jump_insns (index,
3317 expand_expr (node->low, NULL_RTX,
3320 LT, NULL_RTX, mode, unsignedp,
3324 /* Value belongs to this node or to the right-hand subtree. */
3326 emit_cmp_and_jump_insns (index,
3329 expand_expr (node->high, NULL_RTX,
3332 LE, NULL_RTX, mode, unsignedp,
3333 label_rtx (node->code_label));
3335 emit_case_nodes (index, node->right, default_label, index_type);
3338 else if (node->right == 0 && node->left != 0)
3340 /* Deal with values to the right of this node,
3341 if they are possible. */
3342 if (!node_has_high_bound (node, index_type))
3344 emit_cmp_and_jump_insns (index,
3347 expand_expr (node->high, NULL_RTX,
3350 GT, NULL_RTX, mode, unsignedp,
3354 /* Value belongs to this node or to the left-hand subtree. */
3356 emit_cmp_and_jump_insns (index,
3359 expand_expr (node->low, NULL_RTX,
3362 GE, NULL_RTX, mode, unsignedp,
3363 label_rtx (node->code_label));
3365 emit_case_nodes (index, node->left, default_label, index_type);
3370 /* Node has no children so we check low and high bounds to remove
3371 redundant tests. Only one of the bounds can exist,
3372 since otherwise this node is bounded--a case tested already. */
3373 int high_bound = node_has_high_bound (node, index_type);
3374 int low_bound = node_has_low_bound (node, index_type);
3376 if (!high_bound && low_bound)
3378 emit_cmp_and_jump_insns (index,
3381 expand_expr (node->high, NULL_RTX,
3384 GT, NULL_RTX, mode, unsignedp,
3388 else if (!low_bound && high_bound)
3390 emit_cmp_and_jump_insns (index,
3393 expand_expr (node->low, NULL_RTX,
3396 LT, NULL_RTX, mode, unsignedp,
3399 else if (!low_bound && !high_bound)
3401 /* Widen LOW and HIGH to the same width as INDEX. */
3402 tree type = lang_hooks.types.type_for_mode (mode, unsignedp);
3403 tree low = build1 (CONVERT_EXPR, type, node->low);
3404 tree high = build1 (CONVERT_EXPR, type, node->high);
3405 rtx low_rtx, new_index, new_bound;
3407 /* Instead of doing two branches, emit one unsigned branch for
3408 (index-low) > (high-low). */
3409 low_rtx = expand_expr (low, NULL_RTX, mode, 0);
3410 new_index = expand_simple_binop (mode, MINUS, index, low_rtx,
3411 NULL_RTX, unsignedp,
3413 new_bound = expand_expr (fold (build2 (MINUS_EXPR, type,
3417 emit_cmp_and_jump_insns (new_index, new_bound, GT, NULL_RTX,
3418 mode, 1, default_label);
3421 emit_jump (label_rtx (node->code_label));