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"
47 #include "langhooks.h"
53 /* Functions and data structures for expanding case statements. */
55 /* Case label structure, used to hold info on labels within case
56 statements. We handle "range" labels; for a single-value label
57 as in C, the high and low limits are the same.
59 We start with a vector of case nodes sorted in ascending order, and
60 the default label as the last element in the vector. Before expanding
61 to RTL, we transform this vector into a list linked via the RIGHT
62 fields in the case_node struct. Nodes with higher case values are
65 Switch statements can be output in three forms. A branch table is
66 used if there are more than a few labels and the labels are dense
67 within the range between the smallest and largest case value. If a
68 branch table is used, no further manipulations are done with the case
71 The alternative to the use of a branch table is to generate a series
72 of compare and jump insns. When that is done, we use the LEFT, RIGHT,
73 and PARENT fields to hold a binary tree. Initially the tree is
74 totally unbalanced, with everything on the right. We balance the tree
75 with nodes on the left having lower case values than the parent
76 and nodes on the right having higher values. We then output the tree
79 For very small, suitable switch statements, we can generate a series
80 of simple bit test and branches instead. */
82 struct case_node GTY(())
84 struct case_node *left; /* Left son in binary tree */
85 struct case_node *right; /* Right son in binary tree; also node chain */
86 struct case_node *parent; /* Parent of node in binary tree */
87 tree low; /* Lowest index value for this label */
88 tree high; /* Highest index value for this label */
89 tree code_label; /* Label to jump to when node matches */
92 typedef struct case_node case_node;
93 typedef struct case_node *case_node_ptr;
95 /* These are used by estimate_case_costs and balance_case_nodes. */
97 /* This must be a signed type, and non-ANSI compilers lack signed char. */
98 static short cost_table_[129];
99 static int use_cost_table;
100 static int cost_table_initialized;
102 /* Special care is needed because we allow -1, but TREE_INT_CST_LOW
104 #define COST_TABLE(I) cost_table_[(unsigned HOST_WIDE_INT) ((I) + 1)]
106 static int n_occurrences (int, const char *);
107 static bool decl_conflicts_with_clobbers_p (tree, const HARD_REG_SET);
108 static void expand_nl_goto_receiver (void);
109 static bool check_operand_nalternatives (tree, tree);
110 static bool check_unique_operand_names (tree, tree);
111 static char *resolve_operand_name_1 (char *, tree, tree);
112 static void expand_null_return_1 (void);
113 static rtx shift_return_value (rtx);
114 static void expand_value_return (rtx);
115 static void do_jump_if_equal (rtx, rtx, rtx, int);
116 static int estimate_case_costs (case_node_ptr);
117 static bool lshift_cheap_p (void);
118 static int case_bit_test_cmp (const void *, const void *);
119 static void emit_case_bit_tests (tree, tree, tree, tree, case_node_ptr, rtx);
120 static void balance_case_nodes (case_node_ptr *, case_node_ptr);
121 static int node_has_low_bound (case_node_ptr, tree);
122 static int node_has_high_bound (case_node_ptr, tree);
123 static int node_is_bounded (case_node_ptr, tree);
124 static void emit_case_nodes (rtx, case_node_ptr, rtx, tree);
125 static struct case_node *add_case_node (struct case_node *, tree,
129 /* Return the rtx-label that corresponds to a LABEL_DECL,
130 creating it if necessary. */
133 label_rtx (tree label)
135 gcc_assert (TREE_CODE (label) == LABEL_DECL);
137 if (!DECL_RTL_SET_P (label))
139 rtx r = gen_label_rtx ();
140 SET_DECL_RTL (label, r);
141 if (FORCED_LABEL (label) || DECL_NONLOCAL (label))
142 LABEL_PRESERVE_P (r) = 1;
145 return DECL_RTL (label);
148 /* As above, but also put it on the forced-reference list of the
149 function that contains it. */
151 force_label_rtx (tree label)
153 rtx ref = label_rtx (label);
154 tree function = decl_function_context (label);
157 gcc_assert (function);
159 if (function != current_function_decl)
160 p = find_function_data (function);
164 p->expr->x_forced_labels = gen_rtx_EXPR_LIST (VOIDmode, ref,
165 p->expr->x_forced_labels);
169 /* Add an unconditional jump to LABEL as the next sequential instruction. */
172 emit_jump (rtx label)
174 do_pending_stack_adjust ();
175 emit_jump_insn (gen_jump (label));
179 /* Emit code to jump to the address
180 specified by the pointer expression EXP. */
183 expand_computed_goto (tree exp)
185 rtx x = expand_expr (exp, NULL_RTX, VOIDmode, 0);
187 x = convert_memory_address (Pmode, x);
189 do_pending_stack_adjust ();
190 emit_indirect_jump (x);
193 /* Handle goto statements and the labels that they can go to. */
195 /* Specify the location in the RTL code of a label LABEL,
196 which is a LABEL_DECL tree node.
198 This is used for the kind of label that the user can jump to with a
199 goto statement, and for alternatives of a switch or case statement.
200 RTL labels generated for loops and conditionals don't go through here;
201 they are generated directly at the RTL level, by other functions below.
203 Note that this has nothing to do with defining label *names*.
204 Languages vary in how they do that and what that even means. */
207 expand_label (tree label)
209 rtx label_r = label_rtx (label);
211 do_pending_stack_adjust ();
212 emit_label (label_r);
213 if (DECL_NAME (label))
214 LABEL_NAME (DECL_RTL (label)) = IDENTIFIER_POINTER (DECL_NAME (label));
216 if (DECL_NONLOCAL (label))
218 expand_nl_goto_receiver ();
219 nonlocal_goto_handler_labels
220 = gen_rtx_EXPR_LIST (VOIDmode, label_r,
221 nonlocal_goto_handler_labels);
224 if (FORCED_LABEL (label))
225 forced_labels = gen_rtx_EXPR_LIST (VOIDmode, label_r, forced_labels);
227 if (DECL_NONLOCAL (label) || FORCED_LABEL (label))
228 maybe_set_first_label_num (label_r);
231 /* Generate RTL code for a `goto' statement with target label LABEL.
232 LABEL should be a LABEL_DECL tree node that was or will later be
233 defined with `expand_label'. */
236 expand_goto (tree label)
238 #ifdef ENABLE_CHECKING
239 /* Check for a nonlocal goto to a containing function. Should have
240 gotten translated to __builtin_nonlocal_goto. */
241 tree context = decl_function_context (label);
242 gcc_assert (!context || context == current_function_decl);
245 emit_jump (label_rtx (label));
248 /* Return the number of times character C occurs in string S. */
250 n_occurrences (int c, const char *s)
258 /* Generate RTL for an asm statement (explicit assembler code).
259 STRING is a STRING_CST node containing the assembler code text,
260 or an ADDR_EXPR containing a STRING_CST. VOL nonzero means the
261 insn is volatile; don't optimize it. */
264 expand_asm (tree string, int vol)
268 if (TREE_CODE (string) == ADDR_EXPR)
269 string = TREE_OPERAND (string, 0);
271 body = gen_rtx_ASM_INPUT (VOIDmode,
272 ggc_strdup (TREE_STRING_POINTER (string)));
274 MEM_VOLATILE_P (body) = vol;
279 /* Parse the output constraint pointed to by *CONSTRAINT_P. It is the
280 OPERAND_NUMth output operand, indexed from zero. There are NINPUTS
281 inputs and NOUTPUTS outputs to this extended-asm. Upon return,
282 *ALLOWS_MEM will be TRUE iff the constraint allows the use of a
283 memory operand. Similarly, *ALLOWS_REG will be TRUE iff the
284 constraint allows the use of a register operand. And, *IS_INOUT
285 will be true if the operand is read-write, i.e., if it is used as
286 an input as well as an output. If *CONSTRAINT_P is not in
287 canonical form, it will be made canonical. (Note that `+' will be
288 replaced with `=' as part of this process.)
290 Returns TRUE if all went well; FALSE if an error occurred. */
293 parse_output_constraint (const char **constraint_p, int operand_num,
294 int ninputs, int noutputs, bool *allows_mem,
295 bool *allows_reg, bool *is_inout)
297 const char *constraint = *constraint_p;
300 /* Assume the constraint doesn't allow the use of either a register
305 /* Allow the `=' or `+' to not be at the beginning of the string,
306 since it wasn't explicitly documented that way, and there is a
307 large body of code that puts it last. Swap the character to
308 the front, so as not to uglify any place else. */
309 p = strchr (constraint, '=');
311 p = strchr (constraint, '+');
313 /* If the string doesn't contain an `=', issue an error
317 error ("output operand constraint lacks %<=%>");
321 /* If the constraint begins with `+', then the operand is both read
322 from and written to. */
323 *is_inout = (*p == '+');
325 /* Canonicalize the output constraint so that it begins with `='. */
326 if (p != constraint || is_inout)
329 size_t c_len = strlen (constraint);
332 warning ("output constraint %qc for operand %d "
333 "is not at the beginning",
336 /* Make a copy of the constraint. */
337 buf = alloca (c_len + 1);
338 strcpy (buf, constraint);
339 /* Swap the first character and the `=' or `+'. */
340 buf[p - constraint] = buf[0];
341 /* Make sure the first character is an `='. (Until we do this,
342 it might be a `+'.) */
344 /* Replace the constraint with the canonicalized string. */
345 *constraint_p = ggc_alloc_string (buf, c_len);
346 constraint = *constraint_p;
349 /* Loop through the constraint string. */
350 for (p = constraint + 1; *p; p += CONSTRAINT_LEN (*p, p))
355 error ("operand constraint contains incorrectly positioned "
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 %qc", 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 %qc 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 /* Check for overlap between registers marked in CLOBBERED_REGS and
562 anything inappropriate in DECL. Emit error and return TRUE for error,
566 decl_conflicts_with_clobbers_p (tree decl, const HARD_REG_SET clobbered_regs)
568 /* Conflicts between asm-declared register variables and the clobber
569 list are not allowed. */
570 if ((TREE_CODE (decl) == VAR_DECL || TREE_CODE (decl) == PARM_DECL)
571 && DECL_REGISTER (decl)
572 && REG_P (DECL_RTL (decl))
573 && REGNO (DECL_RTL (decl)) < FIRST_PSEUDO_REGISTER)
575 rtx reg = DECL_RTL (decl);
578 for (regno = REGNO (reg);
580 + hard_regno_nregs[REGNO (reg)][GET_MODE (reg)]);
582 if (TEST_HARD_REG_BIT (clobbered_regs, regno))
584 error ("asm-specifier for variable %qs conflicts with "
586 IDENTIFIER_POINTER (DECL_NAME (decl)));
588 /* Reset registerness to stop multiple errors emitted for a
590 DECL_REGISTER (decl) = 0;
597 /* Generate RTL for an asm statement with arguments.
598 STRING is the instruction template.
599 OUTPUTS is a list of output arguments (lvalues); INPUTS a list of inputs.
600 Each output or input has an expression in the TREE_VALUE and
601 and a tree list in TREE_PURPOSE which in turn contains a constraint
602 name in TREE_VALUE (or NULL_TREE) and a constraint string
604 CLOBBERS is a list of STRING_CST nodes each naming a hard register
605 that is clobbered by this insn.
607 Not all kinds of lvalue that may appear in OUTPUTS can be stored directly.
608 Some elements of OUTPUTS may be replaced with trees representing temporary
609 values. The caller should copy those temporary values to the originally
612 VOL nonzero means the insn is volatile; don't optimize it. */
615 expand_asm_operands (tree string, tree outputs, tree inputs,
616 tree clobbers, int vol, location_t locus)
618 rtvec argvec, constraintvec;
620 int ninputs = list_length (inputs);
621 int noutputs = list_length (outputs);
624 HARD_REG_SET clobbered_regs;
625 int clobber_conflict_found = 0;
629 /* Vector of RTX's of evaluated output operands. */
630 rtx *output_rtx = alloca (noutputs * sizeof (rtx));
631 int *inout_opnum = alloca (noutputs * sizeof (int));
632 rtx *real_output_rtx = alloca (noutputs * sizeof (rtx));
633 enum machine_mode *inout_mode
634 = alloca (noutputs * sizeof (enum machine_mode));
635 const char **constraints
636 = alloca ((noutputs + ninputs) * sizeof (const char *));
637 int old_generating_concat_p = generating_concat_p;
639 /* An ASM with no outputs needs to be treated as volatile, for now. */
643 if (! check_operand_nalternatives (outputs, inputs))
646 string = resolve_asm_operand_names (string, outputs, inputs);
648 /* Collect constraints. */
650 for (t = outputs; t ; t = TREE_CHAIN (t), i++)
651 constraints[i] = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
652 for (t = inputs; t ; t = TREE_CHAIN (t), i++)
653 constraints[i] = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
655 /* Sometimes we wish to automatically clobber registers across an asm.
656 Case in point is when the i386 backend moved from cc0 to a hard reg --
657 maintaining source-level compatibility means automatically clobbering
658 the flags register. */
659 clobbers = targetm.md_asm_clobbers (clobbers);
661 /* Count the number of meaningful clobbered registers, ignoring what
662 we would ignore later. */
664 CLEAR_HARD_REG_SET (clobbered_regs);
665 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
667 const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
669 i = decode_reg_name (regname);
670 if (i >= 0 || i == -4)
673 error ("unknown register name %qs in %<asm%>", regname);
675 /* Mark clobbered registers. */
678 /* Clobbering the PIC register is an error. */
679 if (i == (int) PIC_OFFSET_TABLE_REGNUM)
681 error ("PIC register %qs clobbered in %<asm%>", regname);
685 SET_HARD_REG_BIT (clobbered_regs, i);
689 /* First pass over inputs and outputs checks validity and sets
690 mark_addressable if needed. */
693 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
695 tree val = TREE_VALUE (tail);
696 tree type = TREE_TYPE (val);
697 const char *constraint;
702 /* If there's an erroneous arg, emit no insn. */
703 if (type == error_mark_node)
706 /* Try to parse the output constraint. If that fails, there's
707 no point in going further. */
708 constraint = constraints[i];
709 if (!parse_output_constraint (&constraint, i, ninputs, noutputs,
710 &allows_mem, &allows_reg, &is_inout))
717 && REG_P (DECL_RTL (val))
718 && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type))))
719 lang_hooks.mark_addressable (val);
726 if (ninputs + noutputs > MAX_RECOG_OPERANDS)
728 error ("more than %d operands in %<asm%>", MAX_RECOG_OPERANDS);
732 for (i = 0, tail = inputs; tail; i++, tail = TREE_CHAIN (tail))
734 bool allows_reg, allows_mem;
735 const char *constraint;
737 /* If there's an erroneous arg, emit no insn, because the ASM_INPUT
738 would get VOIDmode and that could cause a crash in reload. */
739 if (TREE_TYPE (TREE_VALUE (tail)) == error_mark_node)
742 constraint = constraints[i + noutputs];
743 if (! parse_input_constraint (&constraint, i, ninputs, noutputs, ninout,
744 constraints, &allows_mem, &allows_reg))
747 if (! allows_reg && allows_mem)
748 lang_hooks.mark_addressable (TREE_VALUE (tail));
751 /* Second pass evaluates arguments. */
754 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
756 tree val = TREE_VALUE (tail);
757 tree type = TREE_TYPE (val);
764 ok = parse_output_constraint (&constraints[i], i, ninputs,
765 noutputs, &allows_mem, &allows_reg,
769 /* If an output operand is not a decl or indirect ref and our constraint
770 allows a register, make a temporary to act as an intermediate.
771 Make the asm insn write into that, then our caller will copy it to
772 the real output operand. Likewise for promoted variables. */
774 generating_concat_p = 0;
776 real_output_rtx[i] = NULL_RTX;
777 if ((TREE_CODE (val) == INDIRECT_REF
780 && (allows_mem || REG_P (DECL_RTL (val)))
781 && ! (REG_P (DECL_RTL (val))
782 && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type)))
786 op = expand_expr (val, NULL_RTX, VOIDmode, EXPAND_WRITE);
788 op = validize_mem (op);
790 if (! allows_reg && !MEM_P (op))
791 error ("output number %d not directly addressable", i);
792 if ((! allows_mem && MEM_P (op))
793 || GET_CODE (op) == CONCAT)
795 real_output_rtx[i] = op;
796 op = gen_reg_rtx (GET_MODE (op));
798 emit_move_insn (op, real_output_rtx[i]);
803 op = assign_temp (type, 0, 0, 1);
804 op = validize_mem (op);
805 TREE_VALUE (tail) = make_tree (type, op);
809 generating_concat_p = old_generating_concat_p;
813 inout_mode[ninout] = TYPE_MODE (type);
814 inout_opnum[ninout++] = i;
817 if (decl_conflicts_with_clobbers_p (val, clobbered_regs))
818 clobber_conflict_found = 1;
821 /* Make vectors for the expression-rtx, constraint strings,
822 and named operands. */
824 argvec = rtvec_alloc (ninputs);
825 constraintvec = rtvec_alloc (ninputs);
827 body = gen_rtx_ASM_OPERANDS ((noutputs == 0 ? VOIDmode
828 : GET_MODE (output_rtx[0])),
829 ggc_strdup (TREE_STRING_POINTER (string)),
830 empty_string, 0, argvec, constraintvec,
833 MEM_VOLATILE_P (body) = vol;
835 /* Eval the inputs and put them into ARGVEC.
836 Put their constraints into ASM_INPUTs and store in CONSTRAINTS. */
838 for (i = 0, tail = inputs; tail; tail = TREE_CHAIN (tail), ++i)
840 bool allows_reg, allows_mem;
841 const char *constraint;
846 constraint = constraints[i + noutputs];
847 ok = parse_input_constraint (&constraint, i, ninputs, noutputs, ninout,
848 constraints, &allows_mem, &allows_reg);
851 generating_concat_p = 0;
853 val = TREE_VALUE (tail);
854 type = TREE_TYPE (val);
855 op = expand_expr (val, NULL_RTX, VOIDmode,
856 (allows_mem && !allows_reg
857 ? EXPAND_MEMORY : EXPAND_NORMAL));
859 /* Never pass a CONCAT to an ASM. */
860 if (GET_CODE (op) == CONCAT)
861 op = force_reg (GET_MODE (op), op);
863 op = validize_mem (op);
865 if (asm_operand_ok (op, constraint) <= 0)
868 op = force_reg (TYPE_MODE (type), op);
869 else if (!allows_mem)
870 warning ("asm operand %d probably doesn%'t match constraints",
874 /* We won't recognize either volatile memory or memory
875 with a queued address as available a memory_operand
876 at this point. Ignore it: clearly this *is* a memory. */
880 warning ("use of memory input without lvalue in "
881 "asm operand %d is deprecated", i + noutputs);
885 rtx mem = force_const_mem (TYPE_MODE (type), op);
887 op = validize_mem (mem);
889 op = force_reg (TYPE_MODE (type), op);
892 || GET_CODE (op) == SUBREG
893 || GET_CODE (op) == CONCAT)
895 tree qual_type = build_qualified_type (type,
898 rtx memloc = assign_temp (qual_type, 1, 1, 1);
899 memloc = validize_mem (memloc);
900 emit_move_insn (memloc, op);
906 generating_concat_p = old_generating_concat_p;
907 ASM_OPERANDS_INPUT (body, i) = op;
909 ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, i)
910 = gen_rtx_ASM_INPUT (TYPE_MODE (type),
911 ggc_strdup (constraints[i + noutputs]));
913 if (decl_conflicts_with_clobbers_p (val, clobbered_regs))
914 clobber_conflict_found = 1;
917 /* Protect all the operands from the queue now that they have all been
920 generating_concat_p = 0;
922 /* For in-out operands, copy output rtx to input rtx. */
923 for (i = 0; i < ninout; i++)
925 int j = inout_opnum[i];
928 ASM_OPERANDS_INPUT (body, ninputs - ninout + i)
931 sprintf (buffer, "%d", j);
932 ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, ninputs - ninout + i)
933 = gen_rtx_ASM_INPUT (inout_mode[i], ggc_strdup (buffer));
936 generating_concat_p = old_generating_concat_p;
938 /* Now, for each output, construct an rtx
939 (set OUTPUT (asm_operands INSN OUTPUTCONSTRAINT OUTPUTNUMBER
940 ARGVEC CONSTRAINTS OPNAMES))
941 If there is more than one, put them inside a PARALLEL. */
943 if (noutputs == 1 && nclobbers == 0)
945 ASM_OPERANDS_OUTPUT_CONSTRAINT (body) = ggc_strdup (constraints[0]);
946 emit_insn (gen_rtx_SET (VOIDmode, output_rtx[0], body));
949 else if (noutputs == 0 && nclobbers == 0)
951 /* No output operands: put in a raw ASM_OPERANDS rtx. */
963 body = gen_rtx_PARALLEL (VOIDmode, rtvec_alloc (num + nclobbers));
965 /* For each output operand, store a SET. */
966 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
969 = gen_rtx_SET (VOIDmode,
972 (GET_MODE (output_rtx[i]),
973 ggc_strdup (TREE_STRING_POINTER (string)),
974 ggc_strdup (constraints[i]),
975 i, argvec, constraintvec, locus));
977 MEM_VOLATILE_P (SET_SRC (XVECEXP (body, 0, i))) = vol;
980 /* If there are no outputs (but there are some clobbers)
981 store the bare ASM_OPERANDS into the PARALLEL. */
984 XVECEXP (body, 0, i++) = obody;
986 /* Store (clobber REG) for each clobbered register specified. */
988 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
990 const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
991 int j = decode_reg_name (regname);
996 if (j == -3) /* `cc', which is not a register */
999 if (j == -4) /* `memory', don't cache memory across asm */
1001 XVECEXP (body, 0, i++)
1002 = gen_rtx_CLOBBER (VOIDmode,
1005 gen_rtx_SCRATCH (VOIDmode)));
1009 /* Ignore unknown register, error already signaled. */
1013 /* Use QImode since that's guaranteed to clobber just one reg. */
1014 clobbered_reg = gen_rtx_REG (QImode, j);
1016 /* Do sanity check for overlap between clobbers and respectively
1017 input and outputs that hasn't been handled. Such overlap
1018 should have been detected and reported above. */
1019 if (!clobber_conflict_found)
1023 /* We test the old body (obody) contents to avoid tripping
1024 over the under-construction body. */
1025 for (opno = 0; opno < noutputs; opno++)
1026 if (reg_overlap_mentioned_p (clobbered_reg, output_rtx[opno]))
1027 internal_error ("asm clobber conflict with output operand");
1029 for (opno = 0; opno < ninputs - ninout; opno++)
1030 if (reg_overlap_mentioned_p (clobbered_reg,
1031 ASM_OPERANDS_INPUT (obody, opno)))
1032 internal_error ("asm clobber conflict with input operand");
1035 XVECEXP (body, 0, i++)
1036 = gen_rtx_CLOBBER (VOIDmode, clobbered_reg);
1042 /* For any outputs that needed reloading into registers, spill them
1043 back to where they belong. */
1044 for (i = 0; i < noutputs; ++i)
1045 if (real_output_rtx[i])
1046 emit_move_insn (real_output_rtx[i], output_rtx[i]);
1052 expand_asm_expr (tree exp)
1058 if (ASM_INPUT_P (exp))
1060 expand_asm (ASM_STRING (exp), ASM_VOLATILE_P (exp));
1064 outputs = ASM_OUTPUTS (exp);
1065 noutputs = list_length (outputs);
1066 /* o[I] is the place that output number I should be written. */
1067 o = (tree *) alloca (noutputs * sizeof (tree));
1069 /* Record the contents of OUTPUTS before it is modified. */
1070 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1071 o[i] = TREE_VALUE (tail);
1073 /* Generate the ASM_OPERANDS insn; store into the TREE_VALUEs of
1074 OUTPUTS some trees for where the values were actually stored. */
1075 expand_asm_operands (ASM_STRING (exp), outputs, ASM_INPUTS (exp),
1076 ASM_CLOBBERS (exp), ASM_VOLATILE_P (exp),
1079 /* Copy all the intermediate outputs into the specified outputs. */
1080 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1082 if (o[i] != TREE_VALUE (tail))
1084 expand_assignment (o[i], TREE_VALUE (tail));
1087 /* Restore the original value so that it's correct the next
1088 time we expand this function. */
1089 TREE_VALUE (tail) = o[i];
1094 /* A subroutine of expand_asm_operands. Check that all operands have
1095 the same number of alternatives. Return true if so. */
1098 check_operand_nalternatives (tree outputs, tree inputs)
1100 if (outputs || inputs)
1102 tree tmp = TREE_PURPOSE (outputs ? outputs : inputs);
1104 = n_occurrences (',', TREE_STRING_POINTER (TREE_VALUE (tmp)));
1107 if (nalternatives + 1 > MAX_RECOG_ALTERNATIVES)
1109 error ("too many alternatives in %<asm%>");
1116 const char *constraint
1117 = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tmp)));
1119 if (n_occurrences (',', constraint) != nalternatives)
1121 error ("operand constraints for %<asm%> differ "
1122 "in number of alternatives");
1126 if (TREE_CHAIN (tmp))
1127 tmp = TREE_CHAIN (tmp);
1129 tmp = next, next = 0;
1136 /* A subroutine of expand_asm_operands. Check that all operand names
1137 are unique. Return true if so. We rely on the fact that these names
1138 are identifiers, and so have been canonicalized by get_identifier,
1139 so all we need are pointer comparisons. */
1142 check_unique_operand_names (tree outputs, tree inputs)
1146 for (i = outputs; i ; i = TREE_CHAIN (i))
1148 tree i_name = TREE_PURPOSE (TREE_PURPOSE (i));
1152 for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
1153 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1157 for (i = inputs; i ; i = TREE_CHAIN (i))
1159 tree i_name = TREE_PURPOSE (TREE_PURPOSE (i));
1163 for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
1164 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1166 for (j = outputs; j ; j = TREE_CHAIN (j))
1167 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1174 error ("duplicate asm operand name %qs",
1175 TREE_STRING_POINTER (TREE_PURPOSE (TREE_PURPOSE (i))));
1179 /* A subroutine of expand_asm_operands. Resolve the names of the operands
1180 in *POUTPUTS and *PINPUTS to numbers, and replace the name expansions in
1181 STRING and in the constraints to those numbers. */
1184 resolve_asm_operand_names (tree string, tree outputs, tree inputs)
1191 check_unique_operand_names (outputs, inputs);
1193 /* Substitute [<name>] in input constraint strings. There should be no
1194 named operands in output constraints. */
1195 for (t = inputs; t ; t = TREE_CHAIN (t))
1197 c = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
1198 if (strchr (c, '[') != NULL)
1200 p = buffer = xstrdup (c);
1201 while ((p = strchr (p, '[')) != NULL)
1202 p = resolve_operand_name_1 (p, outputs, inputs);
1203 TREE_VALUE (TREE_PURPOSE (t))
1204 = build_string (strlen (buffer), buffer);
1209 /* Now check for any needed substitutions in the template. */
1210 c = TREE_STRING_POINTER (string);
1211 while ((c = strchr (c, '%')) != NULL)
1215 else if (ISALPHA (c[1]) && c[2] == '[')
1226 /* OK, we need to make a copy so we can perform the substitutions.
1227 Assume that we will not need extra space--we get to remove '['
1228 and ']', which means we cannot have a problem until we have more
1229 than 999 operands. */
1230 buffer = xstrdup (TREE_STRING_POINTER (string));
1231 p = buffer + (c - TREE_STRING_POINTER (string));
1233 while ((p = strchr (p, '%')) != NULL)
1237 else if (ISALPHA (p[1]) && p[2] == '[')
1245 p = resolve_operand_name_1 (p, outputs, inputs);
1248 string = build_string (strlen (buffer), buffer);
1255 /* A subroutine of resolve_operand_names. P points to the '[' for a
1256 potential named operand of the form [<name>]. In place, replace
1257 the name and brackets with a number. Return a pointer to the
1258 balance of the string after substitution. */
1261 resolve_operand_name_1 (char *p, tree outputs, tree inputs)
1268 /* Collect the operand name. */
1269 q = strchr (p, ']');
1272 error ("missing close brace for named operand");
1273 return strchr (p, '\0');
1277 /* Resolve the name to a number. */
1278 for (op = 0, t = outputs; t ; t = TREE_CHAIN (t), op++)
1280 tree name = TREE_PURPOSE (TREE_PURPOSE (t));
1283 const char *c = TREE_STRING_POINTER (name);
1284 if (strncmp (c, p + 1, len) == 0 && c[len] == '\0')
1288 for (t = inputs; t ; t = TREE_CHAIN (t), op++)
1290 tree name = TREE_PURPOSE (TREE_PURPOSE (t));
1293 const char *c = TREE_STRING_POINTER (name);
1294 if (strncmp (c, p + 1, len) == 0 && c[len] == '\0')
1300 error ("undefined named operand %qs", p + 1);
1304 /* Replace the name with the number. Unfortunately, not all libraries
1305 get the return value of sprintf correct, so search for the end of the
1306 generated string by hand. */
1307 sprintf (p, "%d", op);
1308 p = strchr (p, '\0');
1310 /* Verify the no extra buffer space assumption. */
1311 gcc_assert (p <= q);
1313 /* Shift the rest of the buffer down to fill the gap. */
1314 memmove (p, q + 1, strlen (q + 1) + 1);
1319 /* Generate RTL to evaluate the expression EXP. */
1322 expand_expr_stmt (tree exp)
1327 value = expand_expr (exp, const0_rtx, VOIDmode, 0);
1328 type = TREE_TYPE (exp);
1330 /* If all we do is reference a volatile value in memory,
1331 copy it to a register to be sure it is actually touched. */
1332 if (value && MEM_P (value) && TREE_THIS_VOLATILE (exp))
1334 if (TYPE_MODE (type) == VOIDmode)
1336 else if (TYPE_MODE (type) != BLKmode)
1337 value = copy_to_reg (value);
1340 rtx lab = gen_label_rtx ();
1342 /* Compare the value with itself to reference it. */
1343 emit_cmp_and_jump_insns (value, value, EQ,
1344 expand_expr (TYPE_SIZE (type),
1345 NULL_RTX, VOIDmode, 0),
1351 /* Free any temporaries used to evaluate this expression. */
1355 /* Warn if EXP contains any computations whose results are not used.
1356 Return 1 if a warning is printed; 0 otherwise. LOCUS is the
1357 (potential) location of the expression. */
1360 warn_if_unused_value (tree exp, location_t locus)
1363 if (TREE_USED (exp))
1366 /* Don't warn about void constructs. This includes casting to void,
1367 void function calls, and statement expressions with a final cast
1369 if (VOID_TYPE_P (TREE_TYPE (exp)))
1372 if (EXPR_HAS_LOCATION (exp))
1373 locus = EXPR_LOCATION (exp);
1375 switch (TREE_CODE (exp))
1377 case PREINCREMENT_EXPR:
1378 case POSTINCREMENT_EXPR:
1379 case PREDECREMENT_EXPR:
1380 case POSTDECREMENT_EXPR:
1385 case TRY_CATCH_EXPR:
1386 case WITH_CLEANUP_EXPR:
1391 /* For a binding, warn if no side effect within it. */
1392 exp = BIND_EXPR_BODY (exp);
1396 exp = TREE_OPERAND (exp, 0);
1399 case TRUTH_ORIF_EXPR:
1400 case TRUTH_ANDIF_EXPR:
1401 /* In && or ||, warn if 2nd operand has no side effect. */
1402 exp = TREE_OPERAND (exp, 1);
1406 if (TREE_NO_WARNING (exp))
1408 if (warn_if_unused_value (TREE_OPERAND (exp, 0), locus))
1410 /* Let people do `(foo (), 0)' without a warning. */
1411 if (TREE_CONSTANT (TREE_OPERAND (exp, 1)))
1413 exp = TREE_OPERAND (exp, 1);
1418 case NON_LVALUE_EXPR:
1419 /* Don't warn about conversions not explicit in the user's program. */
1420 if (TREE_NO_WARNING (exp))
1422 /* Assignment to a cast usually results in a cast of a modify.
1423 Don't complain about that. There can be an arbitrary number of
1424 casts before the modify, so we must loop until we find the first
1425 non-cast expression and then test to see if that is a modify. */
1427 tree tem = TREE_OPERAND (exp, 0);
1429 while (TREE_CODE (tem) == CONVERT_EXPR || TREE_CODE (tem) == NOP_EXPR)
1430 tem = TREE_OPERAND (tem, 0);
1432 if (TREE_CODE (tem) == MODIFY_EXPR || TREE_CODE (tem) == INIT_EXPR
1433 || TREE_CODE (tem) == CALL_EXPR)
1439 /* Don't warn about automatic dereferencing of references, since
1440 the user cannot control it. */
1441 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (exp, 0))) == REFERENCE_TYPE)
1443 exp = TREE_OPERAND (exp, 0);
1449 /* Referencing a volatile value is a side effect, so don't warn. */
1450 if ((DECL_P (exp) || REFERENCE_CLASS_P (exp))
1451 && TREE_THIS_VOLATILE (exp))
1454 /* If this is an expression which has no operands, there is no value
1455 to be unused. There are no such language-independent codes,
1456 but front ends may define such. */
1457 if (EXPRESSION_CLASS_P (exp) && TREE_CODE_LENGTH (TREE_CODE (exp)) == 0)
1461 /* If this is an expression with side effects, don't warn. */
1462 if (TREE_SIDE_EFFECTS (exp))
1465 warning ("%Hvalue computed is not used", &locus);
1471 /* Generate RTL to return from the current function, with no value.
1472 (That is, we do not do anything about returning any value.) */
1475 expand_null_return (void)
1477 /* If this function was declared to return a value, but we
1478 didn't, clobber the return registers so that they are not
1479 propagated live to the rest of the function. */
1480 clobber_return_register ();
1482 expand_null_return_1 ();
1485 /* Generate RTL to return directly from the current function.
1486 (That is, we bypass any return value.) */
1489 expand_naked_return (void)
1493 clear_pending_stack_adjust ();
1494 do_pending_stack_adjust ();
1496 end_label = naked_return_label;
1498 end_label = naked_return_label = gen_label_rtx ();
1500 emit_jump (end_label);
1503 /* If the current function returns values in the most significant part
1504 of a register, shift return value VAL appropriately. The mode of
1505 the function's return type is known not to be BLKmode. */
1508 shift_return_value (rtx val)
1512 type = TREE_TYPE (DECL_RESULT (current_function_decl));
1513 if (targetm.calls.return_in_msb (type))
1516 HOST_WIDE_INT shift;
1518 target = DECL_RTL (DECL_RESULT (current_function_decl));
1519 shift = (GET_MODE_BITSIZE (GET_MODE (target))
1520 - BITS_PER_UNIT * int_size_in_bytes (type));
1522 val = expand_shift (LSHIFT_EXPR, GET_MODE (target),
1523 gen_lowpart (GET_MODE (target), val),
1524 build_int_cst (NULL_TREE, shift), target, 1);
1530 /* Generate RTL to return from the current function, with value VAL. */
1533 expand_value_return (rtx val)
1535 /* Copy the value to the return location
1536 unless it's already there. */
1538 rtx return_reg = DECL_RTL (DECL_RESULT (current_function_decl));
1539 if (return_reg != val)
1541 tree type = TREE_TYPE (DECL_RESULT (current_function_decl));
1542 if (targetm.calls.promote_function_return (TREE_TYPE (current_function_decl)))
1544 int unsignedp = TYPE_UNSIGNED (type);
1545 enum machine_mode old_mode
1546 = DECL_MODE (DECL_RESULT (current_function_decl));
1547 enum machine_mode mode
1548 = promote_mode (type, old_mode, &unsignedp, 1);
1550 if (mode != old_mode)
1551 val = convert_modes (mode, old_mode, val, unsignedp);
1553 if (GET_CODE (return_reg) == PARALLEL)
1554 emit_group_load (return_reg, val, type, int_size_in_bytes (type));
1556 emit_move_insn (return_reg, val);
1559 expand_null_return_1 ();
1562 /* Output a return with no value. */
1565 expand_null_return_1 (void)
1569 clear_pending_stack_adjust ();
1570 do_pending_stack_adjust ();
1572 end_label = return_label;
1574 end_label = return_label = gen_label_rtx ();
1575 emit_jump (end_label);
1578 /* Generate RTL to evaluate the expression RETVAL and return it
1579 from the current function. */
1582 expand_return (tree retval)
1588 /* If function wants no value, give it none. */
1589 if (TREE_CODE (TREE_TYPE (TREE_TYPE (current_function_decl))) == VOID_TYPE)
1591 expand_expr (retval, NULL_RTX, VOIDmode, 0);
1592 expand_null_return ();
1596 if (retval == error_mark_node)
1598 /* Treat this like a return of no value from a function that
1600 expand_null_return ();
1603 else if ((TREE_CODE (retval) == MODIFY_EXPR
1604 || TREE_CODE (retval) == INIT_EXPR)
1605 && TREE_CODE (TREE_OPERAND (retval, 0)) == RESULT_DECL)
1606 retval_rhs = TREE_OPERAND (retval, 1);
1608 retval_rhs = retval;
1610 result_rtl = DECL_RTL (DECL_RESULT (current_function_decl));
1612 /* If we are returning the RESULT_DECL, then the value has already
1613 been stored into it, so we don't have to do anything special. */
1614 if (TREE_CODE (retval_rhs) == RESULT_DECL)
1615 expand_value_return (result_rtl);
1617 /* If the result is an aggregate that is being returned in one (or more)
1618 registers, load the registers here. The compiler currently can't handle
1619 copying a BLKmode value into registers. We could put this code in a
1620 more general area (for use by everyone instead of just function
1621 call/return), but until this feature is generally usable it is kept here
1622 (and in expand_call). */
1624 else if (retval_rhs != 0
1625 && TYPE_MODE (TREE_TYPE (retval_rhs)) == BLKmode
1626 && REG_P (result_rtl))
1629 unsigned HOST_WIDE_INT bitpos, xbitpos;
1630 unsigned HOST_WIDE_INT padding_correction = 0;
1631 unsigned HOST_WIDE_INT bytes
1632 = int_size_in_bytes (TREE_TYPE (retval_rhs));
1633 int n_regs = (bytes + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
1634 unsigned int bitsize
1635 = MIN (TYPE_ALIGN (TREE_TYPE (retval_rhs)), BITS_PER_WORD);
1636 rtx *result_pseudos = alloca (sizeof (rtx) * n_regs);
1637 rtx result_reg, src = NULL_RTX, dst = NULL_RTX;
1638 rtx result_val = expand_expr (retval_rhs, NULL_RTX, VOIDmode, 0);
1639 enum machine_mode tmpmode, result_reg_mode;
1643 expand_null_return ();
1647 /* If the structure doesn't take up a whole number of words, see
1648 whether the register value should be padded on the left or on
1649 the right. Set PADDING_CORRECTION to the number of padding
1650 bits needed on the left side.
1652 In most ABIs, the structure will be returned at the least end of
1653 the register, which translates to right padding on little-endian
1654 targets and left padding on big-endian targets. The opposite
1655 holds if the structure is returned at the most significant
1656 end of the register. */
1657 if (bytes % UNITS_PER_WORD != 0
1658 && (targetm.calls.return_in_msb (TREE_TYPE (retval_rhs))
1660 : BYTES_BIG_ENDIAN))
1661 padding_correction = (BITS_PER_WORD - ((bytes % UNITS_PER_WORD)
1664 /* Copy the structure BITSIZE bits at a time. */
1665 for (bitpos = 0, xbitpos = padding_correction;
1666 bitpos < bytes * BITS_PER_UNIT;
1667 bitpos += bitsize, xbitpos += bitsize)
1669 /* We need a new destination pseudo each time xbitpos is
1670 on a word boundary and when xbitpos == padding_correction
1671 (the first time through). */
1672 if (xbitpos % BITS_PER_WORD == 0
1673 || xbitpos == padding_correction)
1675 /* Generate an appropriate register. */
1676 dst = gen_reg_rtx (word_mode);
1677 result_pseudos[xbitpos / BITS_PER_WORD] = dst;
1679 /* Clear the destination before we move anything into it. */
1680 emit_move_insn (dst, CONST0_RTX (GET_MODE (dst)));
1683 /* We need a new source operand each time bitpos is on a word
1685 if (bitpos % BITS_PER_WORD == 0)
1686 src = operand_subword_force (result_val,
1687 bitpos / BITS_PER_WORD,
1690 /* Use bitpos for the source extraction (left justified) and
1691 xbitpos for the destination store (right justified). */
1692 store_bit_field (dst, bitsize, xbitpos % BITS_PER_WORD, word_mode,
1693 extract_bit_field (src, bitsize,
1694 bitpos % BITS_PER_WORD, 1,
1695 NULL_RTX, word_mode, word_mode));
1698 tmpmode = GET_MODE (result_rtl);
1699 if (tmpmode == BLKmode)
1701 /* Find the smallest integer mode large enough to hold the
1702 entire structure and use that mode instead of BLKmode
1703 on the USE insn for the return register. */
1704 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
1705 tmpmode != VOIDmode;
1706 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
1707 /* Have we found a large enough mode? */
1708 if (GET_MODE_SIZE (tmpmode) >= bytes)
1711 /* A suitable mode should have been found. */
1712 gcc_assert (tmpmode != VOIDmode);
1714 PUT_MODE (result_rtl, tmpmode);
1717 if (GET_MODE_SIZE (tmpmode) < GET_MODE_SIZE (word_mode))
1718 result_reg_mode = word_mode;
1720 result_reg_mode = tmpmode;
1721 result_reg = gen_reg_rtx (result_reg_mode);
1723 for (i = 0; i < n_regs; i++)
1724 emit_move_insn (operand_subword (result_reg, i, 0, result_reg_mode),
1727 if (tmpmode != result_reg_mode)
1728 result_reg = gen_lowpart (tmpmode, result_reg);
1730 expand_value_return (result_reg);
1732 else if (retval_rhs != 0
1733 && !VOID_TYPE_P (TREE_TYPE (retval_rhs))
1734 && (REG_P (result_rtl)
1735 || (GET_CODE (result_rtl) == PARALLEL)))
1737 /* Calculate the return value into a temporary (usually a pseudo
1739 tree ot = TREE_TYPE (DECL_RESULT (current_function_decl));
1740 tree nt = build_qualified_type (ot, TYPE_QUALS (ot) | TYPE_QUAL_CONST);
1742 val = assign_temp (nt, 0, 0, 1);
1743 val = expand_expr (retval_rhs, val, GET_MODE (val), 0);
1744 val = force_not_mem (val);
1745 /* Return the calculated value. */
1746 expand_value_return (shift_return_value (val));
1750 /* No hard reg used; calculate value into hard return reg. */
1751 expand_expr (retval, const0_rtx, VOIDmode, 0);
1752 expand_value_return (result_rtl);
1756 /* Given a pointer to a BLOCK node return nonzero if (and only if) the node
1757 in question represents the outermost pair of curly braces (i.e. the "body
1758 block") of a function or method.
1760 For any BLOCK node representing a "body block" of a function or method, the
1761 BLOCK_SUPERCONTEXT of the node will point to another BLOCK node which
1762 represents the outermost (function) scope for the function or method (i.e.
1763 the one which includes the formal parameters). The BLOCK_SUPERCONTEXT of
1764 *that* node in turn will point to the relevant FUNCTION_DECL node. */
1767 is_body_block (tree stmt)
1769 if (lang_hooks.no_body_blocks)
1772 if (TREE_CODE (stmt) == BLOCK)
1774 tree parent = BLOCK_SUPERCONTEXT (stmt);
1776 if (parent && TREE_CODE (parent) == BLOCK)
1778 tree grandparent = BLOCK_SUPERCONTEXT (parent);
1780 if (grandparent && TREE_CODE (grandparent) == FUNCTION_DECL)
1788 /* Emit code to restore vital registers at the beginning of a nonlocal goto
1791 expand_nl_goto_receiver (void)
1793 /* Clobber the FP when we get here, so we have to make sure it's
1794 marked as used by this function. */
1795 emit_insn (gen_rtx_USE (VOIDmode, hard_frame_pointer_rtx));
1797 /* Mark the static chain as clobbered here so life information
1798 doesn't get messed up for it. */
1799 emit_insn (gen_rtx_CLOBBER (VOIDmode, static_chain_rtx));
1801 #ifdef HAVE_nonlocal_goto
1802 if (! HAVE_nonlocal_goto)
1804 /* First adjust our frame pointer to its actual value. It was
1805 previously set to the start of the virtual area corresponding to
1806 the stacked variables when we branched here and now needs to be
1807 adjusted to the actual hardware fp value.
1809 Assignments are to virtual registers are converted by
1810 instantiate_virtual_regs into the corresponding assignment
1811 to the underlying register (fp in this case) that makes
1812 the original assignment true.
1813 So the following insn will actually be
1814 decrementing fp by STARTING_FRAME_OFFSET. */
1815 emit_move_insn (virtual_stack_vars_rtx, hard_frame_pointer_rtx);
1817 #if ARG_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
1818 if (fixed_regs[ARG_POINTER_REGNUM])
1820 #ifdef ELIMINABLE_REGS
1821 /* If the argument pointer can be eliminated in favor of the
1822 frame pointer, we don't need to restore it. We assume here
1823 that if such an elimination is present, it can always be used.
1824 This is the case on all known machines; if we don't make this
1825 assumption, we do unnecessary saving on many machines. */
1826 static const struct elims {const int from, to;} elim_regs[] = ELIMINABLE_REGS;
1829 for (i = 0; i < ARRAY_SIZE (elim_regs); i++)
1830 if (elim_regs[i].from == ARG_POINTER_REGNUM
1831 && elim_regs[i].to == HARD_FRAME_POINTER_REGNUM)
1834 if (i == ARRAY_SIZE (elim_regs))
1837 /* Now restore our arg pointer from the address at which it
1838 was saved in our stack frame. */
1839 emit_move_insn (virtual_incoming_args_rtx,
1840 copy_to_reg (get_arg_pointer_save_area (cfun)));
1845 #ifdef HAVE_nonlocal_goto_receiver
1846 if (HAVE_nonlocal_goto_receiver)
1847 emit_insn (gen_nonlocal_goto_receiver ());
1850 /* @@@ This is a kludge. Not all machine descriptions define a blockage
1851 insn, but we must not allow the code we just generated to be reordered
1852 by scheduling. Specifically, the update of the frame pointer must
1853 happen immediately, not later. So emit an ASM_INPUT to act as blockage
1855 emit_insn (gen_rtx_ASM_INPUT (VOIDmode, ""));
1858 /* Generate RTL for the automatic variable declaration DECL.
1859 (Other kinds of declarations are simply ignored if seen here.) */
1862 expand_decl (tree decl)
1866 type = TREE_TYPE (decl);
1868 /* For a CONST_DECL, set mode, alignment, and sizes from those of the
1869 type in case this node is used in a reference. */
1870 if (TREE_CODE (decl) == CONST_DECL)
1872 DECL_MODE (decl) = TYPE_MODE (type);
1873 DECL_ALIGN (decl) = TYPE_ALIGN (type);
1874 DECL_SIZE (decl) = TYPE_SIZE (type);
1875 DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (type);
1879 /* Otherwise, only automatic variables need any expansion done. Static and
1880 external variables, and external functions, will be handled by
1881 `assemble_variable' (called from finish_decl). TYPE_DECL requires
1882 nothing. PARM_DECLs are handled in `assign_parms'. */
1883 if (TREE_CODE (decl) != VAR_DECL)
1886 if (TREE_STATIC (decl) || DECL_EXTERNAL (decl))
1889 /* Create the RTL representation for the variable. */
1891 if (type == error_mark_node)
1892 SET_DECL_RTL (decl, gen_rtx_MEM (BLKmode, const0_rtx));
1894 else if (DECL_SIZE (decl) == 0)
1895 /* Variable with incomplete type. */
1898 if (DECL_INITIAL (decl) == 0)
1899 /* Error message was already done; now avoid a crash. */
1900 x = gen_rtx_MEM (BLKmode, const0_rtx);
1902 /* An initializer is going to decide the size of this array.
1903 Until we know the size, represent its address with a reg. */
1904 x = gen_rtx_MEM (BLKmode, gen_reg_rtx (Pmode));
1906 set_mem_attributes (x, decl, 1);
1907 SET_DECL_RTL (decl, x);
1909 else if (use_register_for_decl (decl))
1911 /* Automatic variable that can go in a register. */
1912 int unsignedp = TYPE_UNSIGNED (type);
1913 enum machine_mode reg_mode
1914 = promote_mode (type, DECL_MODE (decl), &unsignedp, 0);
1916 SET_DECL_RTL (decl, gen_reg_rtx (reg_mode));
1918 /* Note if the object is a user variable. */
1919 if (!DECL_ARTIFICIAL (decl))
1921 mark_user_reg (DECL_RTL (decl));
1923 /* Trust user variables which have a pointer type to really
1924 be pointers. Do not trust compiler generated temporaries
1925 as our type system is totally busted as it relates to
1926 pointer arithmetic which translates into lots of compiler
1927 generated objects with pointer types, but which are not really
1929 if (POINTER_TYPE_P (type))
1930 mark_reg_pointer (DECL_RTL (decl),
1931 TYPE_ALIGN (TREE_TYPE (TREE_TYPE (decl))));
1935 else if (TREE_CODE (DECL_SIZE_UNIT (decl)) == INTEGER_CST
1936 && ! (flag_stack_check && ! STACK_CHECK_BUILTIN
1937 && 0 < compare_tree_int (DECL_SIZE_UNIT (decl),
1938 STACK_CHECK_MAX_VAR_SIZE)))
1940 /* Variable of fixed size that goes on the stack. */
1945 /* If we previously made RTL for this decl, it must be an array
1946 whose size was determined by the initializer.
1947 The old address was a register; set that register now
1948 to the proper address. */
1949 if (DECL_RTL_SET_P (decl))
1951 gcc_assert (MEM_P (DECL_RTL (decl)));
1952 gcc_assert (REG_P (XEXP (DECL_RTL (decl), 0)));
1953 oldaddr = XEXP (DECL_RTL (decl), 0);
1956 /* Set alignment we actually gave this decl. */
1957 DECL_ALIGN (decl) = (DECL_MODE (decl) == BLKmode ? BIGGEST_ALIGNMENT
1958 : GET_MODE_BITSIZE (DECL_MODE (decl)));
1959 DECL_USER_ALIGN (decl) = 0;
1961 x = assign_temp (decl, 1, 1, 1);
1962 set_mem_attributes (x, decl, 1);
1963 SET_DECL_RTL (decl, x);
1967 addr = force_operand (XEXP (DECL_RTL (decl), 0), oldaddr);
1968 if (addr != oldaddr)
1969 emit_move_insn (oldaddr, addr);
1973 /* Dynamic-size object: must push space on the stack. */
1975 rtx address, size, x;
1977 /* Record the stack pointer on entry to block, if have
1978 not already done so. */
1979 do_pending_stack_adjust ();
1981 /* Compute the variable's size, in bytes. This will expand any
1982 needed SAVE_EXPRs for the first time. */
1983 size = expand_expr (DECL_SIZE_UNIT (decl), NULL_RTX, VOIDmode, 0);
1986 /* Allocate space on the stack for the variable. Note that
1987 DECL_ALIGN says how the variable is to be aligned and we
1988 cannot use it to conclude anything about the alignment of
1990 address = allocate_dynamic_stack_space (size, NULL_RTX,
1991 TYPE_ALIGN (TREE_TYPE (decl)));
1993 /* Reference the variable indirect through that rtx. */
1994 x = gen_rtx_MEM (DECL_MODE (decl), address);
1995 set_mem_attributes (x, decl, 1);
1996 SET_DECL_RTL (decl, x);
1999 /* Indicate the alignment we actually gave this variable. */
2000 #ifdef STACK_BOUNDARY
2001 DECL_ALIGN (decl) = STACK_BOUNDARY;
2003 DECL_ALIGN (decl) = BIGGEST_ALIGNMENT;
2005 DECL_USER_ALIGN (decl) = 0;
2009 /* Emit code to save the current value of stack. */
2011 expand_stack_save (void)
2015 do_pending_stack_adjust ();
2016 emit_stack_save (SAVE_BLOCK, &ret, NULL_RTX);
2020 /* Emit code to restore the current value of stack. */
2022 expand_stack_restore (tree var)
2024 rtx sa = DECL_RTL (var);
2026 emit_stack_restore (SAVE_BLOCK, sa, NULL_RTX);
2029 /* DECL is an anonymous union. CLEANUP is a cleanup for DECL.
2030 DECL_ELTS is the list of elements that belong to DECL's type.
2031 In each, the TREE_VALUE is a VAR_DECL, and the TREE_PURPOSE a cleanup. */
2034 expand_anon_union_decl (tree decl, tree cleanup ATTRIBUTE_UNUSED,
2040 /* If any of the elements are addressable, so is the entire union. */
2041 for (t = decl_elts; t; t = TREE_CHAIN (t))
2042 if (TREE_ADDRESSABLE (TREE_VALUE (t)))
2044 TREE_ADDRESSABLE (decl) = 1;
2049 x = DECL_RTL (decl);
2051 /* Go through the elements, assigning RTL to each. */
2052 for (t = decl_elts; t; t = TREE_CHAIN (t))
2054 tree decl_elt = TREE_VALUE (t);
2055 enum machine_mode mode = TYPE_MODE (TREE_TYPE (decl_elt));
2058 /* If any of the elements are addressable, so is the entire
2060 if (TREE_USED (decl_elt))
2061 TREE_USED (decl) = 1;
2063 /* Propagate the union's alignment to the elements. */
2064 DECL_ALIGN (decl_elt) = DECL_ALIGN (decl);
2065 DECL_USER_ALIGN (decl_elt) = DECL_USER_ALIGN (decl);
2067 /* If the element has BLKmode and the union doesn't, the union is
2068 aligned such that the element doesn't need to have BLKmode, so
2069 change the element's mode to the appropriate one for its size. */
2070 if (mode == BLKmode && DECL_MODE (decl) != BLKmode)
2071 DECL_MODE (decl_elt) = mode
2072 = mode_for_size_tree (DECL_SIZE (decl_elt), MODE_INT, 1);
2074 if (mode == GET_MODE (x))
2077 /* (SUBREG (MEM ...)) at RTL generation time is invalid, so we
2078 instead create a new MEM rtx with the proper mode. */
2079 decl_rtl = adjust_address_nv (x, mode, 0);
2082 gcc_assert (REG_P (x));
2083 decl_rtl = gen_lowpart_SUBREG (mode, x);
2085 SET_DECL_RTL (decl_elt, decl_rtl);
2089 /* Do the insertion of a case label into case_list. The labels are
2090 fed to us in descending order from the sorted vector of case labels used
2091 in the tree part of the middle end. So the list we construct is
2092 sorted in ascending order. The bounds on the case range, LOW and HIGH,
2093 are converted to case's index type TYPE. */
2095 static struct case_node *
2096 add_case_node (struct case_node *head, tree type, tree low, tree high,
2099 tree min_value, max_value;
2100 struct case_node *r;
2102 gcc_assert (TREE_CODE (low) == INTEGER_CST);
2103 gcc_assert (!high || TREE_CODE (high) == INTEGER_CST);
2105 min_value = TYPE_MIN_VALUE (type);
2106 max_value = TYPE_MAX_VALUE (type);
2108 /* If there's no HIGH value, then this is not a case range; it's
2109 just a simple case label. But that's just a degenerate case
2111 If the bounds are equal, turn this into the one-value case. */
2112 if (!high || tree_int_cst_equal (low, high))
2114 /* If the simple case value is unreachable, ignore it. */
2115 if ((TREE_CODE (min_value) == INTEGER_CST
2116 && tree_int_cst_compare (low, min_value) < 0)
2117 || (TREE_CODE (max_value) == INTEGER_CST
2118 && tree_int_cst_compare (low, max_value) > 0))
2120 low = fold_convert (type, low);
2125 /* If the entire case range is unreachable, ignore it. */
2126 if ((TREE_CODE (min_value) == INTEGER_CST
2127 && tree_int_cst_compare (high, min_value) < 0)
2128 || (TREE_CODE (max_value) == INTEGER_CST
2129 && tree_int_cst_compare (low, max_value) > 0))
2132 /* If the lower bound is less than the index type's minimum
2133 value, truncate the range bounds. */
2134 if (TREE_CODE (min_value) == INTEGER_CST
2135 && tree_int_cst_compare (low, min_value) < 0)
2137 low = fold_convert (type, low);
2139 /* If the upper bound is greater than the index type's maximum
2140 value, truncate the range bounds. */
2141 if (TREE_CODE (max_value) == INTEGER_CST
2142 && tree_int_cst_compare (high, max_value) > 0)
2144 high = fold_convert (type, high);
2148 /* Add this label to the chain. */
2149 r = ggc_alloc (sizeof (struct case_node));
2152 r->code_label = label;
2153 r->parent = r->left = NULL;
2158 /* Maximum number of case bit tests. */
2159 #define MAX_CASE_BIT_TESTS 3
2161 /* By default, enable case bit tests on targets with ashlsi3. */
2162 #ifndef CASE_USE_BIT_TESTS
2163 #define CASE_USE_BIT_TESTS (ashl_optab->handlers[word_mode].insn_code \
2164 != CODE_FOR_nothing)
2168 /* A case_bit_test represents a set of case nodes that may be
2169 selected from using a bit-wise comparison. HI and LO hold
2170 the integer to be tested against, LABEL contains the label
2171 to jump to upon success and BITS counts the number of case
2172 nodes handled by this test, typically the number of bits
2175 struct case_bit_test
2183 /* Determine whether "1 << x" is relatively cheap in word_mode. */
2186 bool lshift_cheap_p (void)
2188 static bool init = false;
2189 static bool cheap = true;
2193 rtx reg = gen_rtx_REG (word_mode, 10000);
2194 int cost = rtx_cost (gen_rtx_ASHIFT (word_mode, const1_rtx, reg), SET);
2195 cheap = cost < COSTS_N_INSNS (3);
2202 /* Comparison function for qsort to order bit tests by decreasing
2203 number of case nodes, i.e. the node with the most cases gets
2207 case_bit_test_cmp (const void *p1, const void *p2)
2209 const struct case_bit_test *d1 = p1;
2210 const struct case_bit_test *d2 = p2;
2212 return d2->bits - d1->bits;
2215 /* Expand a switch statement by a short sequence of bit-wise
2216 comparisons. "switch(x)" is effectively converted into
2217 "if ((1 << (x-MINVAL)) & CST)" where CST and MINVAL are
2220 INDEX_EXPR is the value being switched on, which is of
2221 type INDEX_TYPE. MINVAL is the lowest case value of in
2222 the case nodes, of INDEX_TYPE type, and RANGE is highest
2223 value minus MINVAL, also of type INDEX_TYPE. NODES is
2224 the set of case nodes, and DEFAULT_LABEL is the label to
2225 branch to should none of the cases match.
2227 There *MUST* be MAX_CASE_BIT_TESTS or less unique case
2231 emit_case_bit_tests (tree index_type, tree index_expr, tree minval,
2232 tree range, case_node_ptr nodes, rtx default_label)
2234 struct case_bit_test test[MAX_CASE_BIT_TESTS];
2235 enum machine_mode mode;
2236 rtx expr, index, label;
2237 unsigned int i,j,lo,hi;
2238 struct case_node *n;
2242 for (n = nodes; n; n = n->right)
2244 label = label_rtx (n->code_label);
2245 for (i = 0; i < count; i++)
2246 if (label == test[i].label)
2251 gcc_assert (count < MAX_CASE_BIT_TESTS);
2254 test[i].label = label;
2261 lo = tree_low_cst (fold (build2 (MINUS_EXPR, index_type,
2262 n->low, minval)), 1);
2263 hi = tree_low_cst (fold (build2 (MINUS_EXPR, index_type,
2264 n->high, minval)), 1);
2265 for (j = lo; j <= hi; j++)
2266 if (j >= HOST_BITS_PER_WIDE_INT)
2267 test[i].hi |= (HOST_WIDE_INT) 1 << (j - HOST_BITS_PER_INT);
2269 test[i].lo |= (HOST_WIDE_INT) 1 << j;
2272 qsort (test, count, sizeof(*test), case_bit_test_cmp);
2274 index_expr = fold (build2 (MINUS_EXPR, index_type,
2275 convert (index_type, index_expr),
2276 convert (index_type, minval)));
2277 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
2278 do_pending_stack_adjust ();
2280 mode = TYPE_MODE (index_type);
2281 expr = expand_expr (range, NULL_RTX, VOIDmode, 0);
2282 emit_cmp_and_jump_insns (index, expr, GTU, NULL_RTX, mode, 1,
2285 index = convert_to_mode (word_mode, index, 0);
2286 index = expand_binop (word_mode, ashl_optab, const1_rtx,
2287 index, NULL_RTX, 1, OPTAB_WIDEN);
2289 for (i = 0; i < count; i++)
2291 expr = immed_double_const (test[i].lo, test[i].hi, word_mode);
2292 expr = expand_binop (word_mode, and_optab, index, expr,
2293 NULL_RTX, 1, OPTAB_WIDEN);
2294 emit_cmp_and_jump_insns (expr, const0_rtx, NE, NULL_RTX,
2295 word_mode, 1, test[i].label);
2298 emit_jump (default_label);
2302 #define HAVE_casesi 0
2305 #ifndef HAVE_tablejump
2306 #define HAVE_tablejump 0
2309 /* Terminate a case (Pascal) or switch (C) statement
2310 in which ORIG_INDEX is the expression to be tested.
2311 If ORIG_TYPE is not NULL, it is the original ORIG_INDEX
2312 type as given in the source before any compiler conversions.
2313 Generate the code to test it and jump to the right place. */
2316 expand_case (tree exp)
2318 tree minval = NULL_TREE, maxval = NULL_TREE, range = NULL_TREE;
2319 rtx default_label = 0;
2320 struct case_node *n, *m;
2321 unsigned int count, uniq;
2327 rtx before_case, end, lab;
2329 tree vec = SWITCH_LABELS (exp);
2330 tree orig_type = TREE_TYPE (exp);
2331 tree index_expr = SWITCH_COND (exp);
2332 tree index_type = TREE_TYPE (index_expr);
2333 int unsignedp = TYPE_UNSIGNED (index_type);
2335 /* The insn after which the case dispatch should finally
2336 be emitted. Zero for a dummy. */
2339 /* A list of case labels; it is first built as a list and it may then
2340 be rearranged into a nearly balanced binary tree. */
2341 struct case_node *case_list = 0;
2343 /* Label to jump to if no case matches. */
2344 tree default_label_decl = 0;
2346 /* The switch body is lowered in gimplify.c, we should never have
2347 switches with a non-NULL SWITCH_BODY here. */
2348 gcc_assert (!SWITCH_BODY (exp));
2349 gcc_assert (SWITCH_LABELS (exp));
2351 do_pending_stack_adjust ();
2353 /* An ERROR_MARK occurs for various reasons including invalid data type. */
2354 if (index_type != error_mark_node)
2356 for (i = TREE_VEC_LENGTH (vec); --i >= 0; )
2358 tree elt = TREE_VEC_ELT (vec, i);
2360 /* Handle default labels specially. */
2361 if (!CASE_HIGH (elt) && !CASE_LOW (elt))
2363 gcc_assert (!default_label_decl);
2364 default_label_decl = CASE_LABEL (elt);
2367 case_list = add_case_node (case_list, index_type,
2368 CASE_LOW (elt), CASE_HIGH (elt),
2373 /* Make sure start points to something that won't need any
2374 transformation before the end of this function. */
2375 start = get_last_insn ();
2376 if (! NOTE_P (start))
2378 emit_note (NOTE_INSN_DELETED);
2379 start = get_last_insn ();
2382 /* If we don't have a default-label, create one here,
2383 after the body of the switch. */
2384 if (default_label_decl == 0)
2387 = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
2388 expand_label (default_label_decl);
2390 default_label = label_rtx (default_label_decl);
2392 before_case = get_last_insn ();
2394 /* Get upper and lower bounds of case values.
2395 Also convert all the case values to the index expr's data type. */
2399 for (n = case_list; n; n = n->right)
2401 /* Count the elements and track the largest and smallest
2402 of them (treating them as signed even if they are not). */
2410 if (INT_CST_LT (n->low, minval))
2412 if (INT_CST_LT (maxval, n->high))
2415 /* A range counts double, since it requires two compares. */
2416 if (! tree_int_cst_equal (n->low, n->high))
2419 /* Count the number of unique case node targets. */
2421 lab = label_rtx (n->code_label);
2422 for (m = case_list; m != n; m = m->right)
2423 if (label_rtx (m->code_label) == lab)
2430 /* Compute span of values. */
2432 range = fold (build2 (MINUS_EXPR, index_type, maxval, minval));
2436 expand_expr (index_expr, const0_rtx, VOIDmode, 0);
2437 emit_jump (default_label);
2440 /* Try implementing this switch statement by a short sequence of
2441 bit-wise comparisons. However, we let the binary-tree case
2442 below handle constant index expressions. */
2443 else if (CASE_USE_BIT_TESTS
2444 && ! TREE_CONSTANT (index_expr)
2445 && compare_tree_int (range, GET_MODE_BITSIZE (word_mode)) < 0
2446 && compare_tree_int (range, 0) > 0
2447 && lshift_cheap_p ()
2448 && ((uniq == 1 && count >= 3)
2449 || (uniq == 2 && count >= 5)
2450 || (uniq == 3 && count >= 6)))
2452 /* Optimize the case where all the case values fit in a
2453 word without having to subtract MINVAL. In this case,
2454 we can optimize away the subtraction. */
2455 if (compare_tree_int (minval, 0) > 0
2456 && compare_tree_int (maxval, GET_MODE_BITSIZE (word_mode)) < 0)
2458 minval = integer_zero_node;
2461 emit_case_bit_tests (index_type, index_expr, minval, range,
2462 case_list, default_label);
2465 /* If range of values is much bigger than number of values,
2466 make a sequence of conditional branches instead of a dispatch.
2467 If the switch-index is a constant, do it this way
2468 because we can optimize it. */
2470 else if (count < case_values_threshold ()
2471 || compare_tree_int (range,
2472 (optimize_size ? 3 : 10) * count) > 0
2473 /* RANGE may be signed, and really large ranges will show up
2474 as negative numbers. */
2475 || compare_tree_int (range, 0) < 0
2476 #ifndef ASM_OUTPUT_ADDR_DIFF_ELT
2479 || TREE_CONSTANT (index_expr)
2480 /* If neither casesi or tablejump is available, we can
2481 only go this way. */
2482 || (!HAVE_casesi && !HAVE_tablejump))
2484 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
2486 /* If the index is a short or char that we do not have
2487 an insn to handle comparisons directly, convert it to
2488 a full integer now, rather than letting each comparison
2489 generate the conversion. */
2491 if (GET_MODE_CLASS (GET_MODE (index)) == MODE_INT
2492 && ! have_insn_for (COMPARE, GET_MODE (index)))
2494 enum machine_mode wider_mode;
2495 for (wider_mode = GET_MODE (index); wider_mode != VOIDmode;
2496 wider_mode = GET_MODE_WIDER_MODE (wider_mode))
2497 if (have_insn_for (COMPARE, wider_mode))
2499 index = convert_to_mode (wider_mode, index, unsignedp);
2504 do_pending_stack_adjust ();
2507 index = copy_to_reg (index);
2508 if (GET_CODE (index) == CONST_INT
2509 || TREE_CODE (index_expr) == INTEGER_CST)
2511 /* Make a tree node with the proper constant value
2512 if we don't already have one. */
2513 if (TREE_CODE (index_expr) != INTEGER_CST)
2516 = build_int_cst_wide (NULL_TREE, INTVAL (index),
2517 unsignedp || INTVAL (index) >= 0
2519 index_expr = convert (index_type, index_expr);
2522 /* For constant index expressions we need only
2523 issue an unconditional branch to the appropriate
2524 target code. The job of removing any unreachable
2525 code is left to the optimization phase if the
2526 "-O" option is specified. */
2527 for (n = case_list; n; n = n->right)
2528 if (! tree_int_cst_lt (index_expr, n->low)
2529 && ! tree_int_cst_lt (n->high, index_expr))
2533 emit_jump (label_rtx (n->code_label));
2535 emit_jump (default_label);
2539 /* If the index expression is not constant we generate
2540 a binary decision tree to select the appropriate
2541 target code. This is done as follows:
2543 The list of cases is rearranged into a binary tree,
2544 nearly optimal assuming equal probability for each case.
2546 The tree is transformed into RTL, eliminating
2547 redundant test conditions at the same time.
2549 If program flow could reach the end of the
2550 decision tree an unconditional jump to the
2551 default code is emitted. */
2554 = (TREE_CODE (orig_type) != ENUMERAL_TYPE
2555 && estimate_case_costs (case_list));
2556 balance_case_nodes (&case_list, NULL);
2557 emit_case_nodes (index, case_list, default_label, index_type);
2558 emit_jump (default_label);
2563 table_label = gen_label_rtx ();
2564 if (! try_casesi (index_type, index_expr, minval, range,
2565 table_label, default_label))
2568 index_type = integer_type_node;
2570 /* Index jumptables from zero for suitable values of
2571 minval to avoid a subtraction. */
2573 && compare_tree_int (minval, 0) > 0
2574 && compare_tree_int (minval, 3) < 0)
2576 minval = integer_zero_node;
2580 ok = try_tablejump (index_type, index_expr, minval, range,
2581 table_label, default_label);
2585 /* Get table of labels to jump to, in order of case index. */
2587 ncases = tree_low_cst (range, 0) + 1;
2588 labelvec = alloca (ncases * sizeof (rtx));
2589 memset (labelvec, 0, ncases * sizeof (rtx));
2591 for (n = case_list; n; n = n->right)
2593 /* Compute the low and high bounds relative to the minimum
2594 value since that should fit in a HOST_WIDE_INT while the
2595 actual values may not. */
2597 = tree_low_cst (fold (build2 (MINUS_EXPR, index_type,
2598 n->low, minval)), 1);
2599 HOST_WIDE_INT i_high
2600 = tree_low_cst (fold (build2 (MINUS_EXPR, index_type,
2601 n->high, minval)), 1);
2604 for (i = i_low; i <= i_high; i ++)
2606 = gen_rtx_LABEL_REF (Pmode, label_rtx (n->code_label));
2609 /* Fill in the gaps with the default. */
2610 for (i = 0; i < ncases; i++)
2611 if (labelvec[i] == 0)
2612 labelvec[i] = gen_rtx_LABEL_REF (Pmode, default_label);
2614 /* Output the table. */
2615 emit_label (table_label);
2617 if (CASE_VECTOR_PC_RELATIVE || flag_pic)
2618 emit_jump_insn (gen_rtx_ADDR_DIFF_VEC (CASE_VECTOR_MODE,
2619 gen_rtx_LABEL_REF (Pmode, table_label),
2620 gen_rtvec_v (ncases, labelvec),
2621 const0_rtx, const0_rtx));
2623 emit_jump_insn (gen_rtx_ADDR_VEC (CASE_VECTOR_MODE,
2624 gen_rtvec_v (ncases, labelvec)));
2626 /* If the case insn drops through the table,
2627 after the table we must jump to the default-label.
2628 Otherwise record no drop-through after the table. */
2629 #ifdef CASE_DROPS_THROUGH
2630 emit_jump (default_label);
2636 before_case = NEXT_INSN (before_case);
2637 end = get_last_insn ();
2638 fail = squeeze_notes (&before_case, &end);
2640 reorder_insns (before_case, end, start);
2646 /* Generate code to jump to LABEL if OP1 and OP2 are equal. */
2649 do_jump_if_equal (rtx op1, rtx op2, rtx label, int unsignedp)
2651 if (GET_CODE (op1) == CONST_INT && GET_CODE (op2) == CONST_INT)
2657 emit_cmp_and_jump_insns (op1, op2, EQ, NULL_RTX,
2658 (GET_MODE (op1) == VOIDmode
2659 ? GET_MODE (op2) : GET_MODE (op1)),
2663 /* Not all case values are encountered equally. This function
2664 uses a heuristic to weight case labels, in cases where that
2665 looks like a reasonable thing to do.
2667 Right now, all we try to guess is text, and we establish the
2670 chars above space: 16
2679 If we find any cases in the switch that are not either -1 or in the range
2680 of valid ASCII characters, or are control characters other than those
2681 commonly used with "\", don't treat this switch scanning text.
2683 Return 1 if these nodes are suitable for cost estimation, otherwise
2687 estimate_case_costs (case_node_ptr node)
2689 tree min_ascii = integer_minus_one_node;
2690 tree max_ascii = convert (TREE_TYPE (node->high),
2691 build_int_cst (NULL_TREE, 127));
2695 /* If we haven't already made the cost table, make it now. Note that the
2696 lower bound of the table is -1, not zero. */
2698 if (! cost_table_initialized)
2700 cost_table_initialized = 1;
2702 for (i = 0; i < 128; i++)
2705 COST_TABLE (i) = 16;
2706 else if (ISPUNCT (i))
2708 else if (ISCNTRL (i))
2709 COST_TABLE (i) = -1;
2712 COST_TABLE (' ') = 8;
2713 COST_TABLE ('\t') = 4;
2714 COST_TABLE ('\0') = 4;
2715 COST_TABLE ('\n') = 2;
2716 COST_TABLE ('\f') = 1;
2717 COST_TABLE ('\v') = 1;
2718 COST_TABLE ('\b') = 1;
2721 /* See if all the case expressions look like text. It is text if the
2722 constant is >= -1 and the highest constant is <= 127. Do all comparisons
2723 as signed arithmetic since we don't want to ever access cost_table with a
2724 value less than -1. Also check that none of the constants in a range
2725 are strange control characters. */
2727 for (n = node; n; n = n->right)
2729 if ((INT_CST_LT (n->low, min_ascii)) || INT_CST_LT (max_ascii, n->high))
2732 for (i = (HOST_WIDE_INT) TREE_INT_CST_LOW (n->low);
2733 i <= (HOST_WIDE_INT) TREE_INT_CST_LOW (n->high); i++)
2734 if (COST_TABLE (i) < 0)
2738 /* All interesting values are within the range of interesting
2739 ASCII characters. */
2743 /* Take an ordered list of case nodes
2744 and transform them into a near optimal binary tree,
2745 on the assumption that any target code selection value is as
2746 likely as any other.
2748 The transformation is performed by splitting the ordered
2749 list into two equal sections plus a pivot. The parts are
2750 then attached to the pivot as left and right branches. Each
2751 branch is then transformed recursively. */
2754 balance_case_nodes (case_node_ptr *head, case_node_ptr parent)
2767 /* Count the number of entries on branch. Also count the ranges. */
2771 if (!tree_int_cst_equal (np->low, np->high))
2775 cost += COST_TABLE (TREE_INT_CST_LOW (np->high));
2779 cost += COST_TABLE (TREE_INT_CST_LOW (np->low));
2787 /* Split this list if it is long enough for that to help. */
2792 /* Find the place in the list that bisects the list's total cost,
2793 Here I gets half the total cost. */
2798 /* Skip nodes while their cost does not reach that amount. */
2799 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
2800 i -= COST_TABLE (TREE_INT_CST_LOW ((*npp)->high));
2801 i -= COST_TABLE (TREE_INT_CST_LOW ((*npp)->low));
2804 npp = &(*npp)->right;
2809 /* Leave this branch lopsided, but optimize left-hand
2810 side and fill in `parent' fields for right-hand side. */
2812 np->parent = parent;
2813 balance_case_nodes (&np->left, np);
2814 for (; np->right; np = np->right)
2815 np->right->parent = np;
2819 /* If there are just three nodes, split at the middle one. */
2821 npp = &(*npp)->right;
2824 /* Find the place in the list that bisects the list's total cost,
2825 where ranges count as 2.
2826 Here I gets half the total cost. */
2827 i = (i + ranges + 1) / 2;
2830 /* Skip nodes while their cost does not reach that amount. */
2831 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
2836 npp = &(*npp)->right;
2841 np->parent = parent;
2844 /* Optimize each of the two split parts. */
2845 balance_case_nodes (&np->left, np);
2846 balance_case_nodes (&np->right, np);
2850 /* Else leave this branch as one level,
2851 but fill in `parent' fields. */
2853 np->parent = parent;
2854 for (; np->right; np = np->right)
2855 np->right->parent = np;
2860 /* Search the parent sections of the case node tree
2861 to see if a test for the lower bound of NODE would be redundant.
2862 INDEX_TYPE is the type of the index expression.
2864 The instructions to generate the case decision tree are
2865 output in the same order as nodes are processed so it is
2866 known that if a parent node checks the range of the current
2867 node minus one that the current node is bounded at its lower
2868 span. Thus the test would be redundant. */
2871 node_has_low_bound (case_node_ptr node, tree index_type)
2874 case_node_ptr pnode;
2876 /* If the lower bound of this node is the lowest value in the index type,
2877 we need not test it. */
2879 if (tree_int_cst_equal (node->low, TYPE_MIN_VALUE (index_type)))
2882 /* If this node has a left branch, the value at the left must be less
2883 than that at this node, so it cannot be bounded at the bottom and
2884 we need not bother testing any further. */
2889 low_minus_one = fold (build2 (MINUS_EXPR, TREE_TYPE (node->low),
2890 node->low, integer_one_node));
2892 /* If the subtraction above overflowed, we can't verify anything.
2893 Otherwise, look for a parent that tests our value - 1. */
2895 if (! tree_int_cst_lt (low_minus_one, node->low))
2898 for (pnode = node->parent; pnode; pnode = pnode->parent)
2899 if (tree_int_cst_equal (low_minus_one, pnode->high))
2905 /* Search the parent sections of the case node tree
2906 to see if a test for the upper bound of NODE would be redundant.
2907 INDEX_TYPE is the type of the index expression.
2909 The instructions to generate the case decision tree are
2910 output in the same order as nodes are processed so it is
2911 known that if a parent node checks the range of the current
2912 node plus one that the current node is bounded at its upper
2913 span. Thus the test would be redundant. */
2916 node_has_high_bound (case_node_ptr node, tree index_type)
2919 case_node_ptr pnode;
2921 /* If there is no upper bound, obviously no test is needed. */
2923 if (TYPE_MAX_VALUE (index_type) == NULL)
2926 /* If the upper bound of this node is the highest value in the type
2927 of the index expression, we need not test against it. */
2929 if (tree_int_cst_equal (node->high, TYPE_MAX_VALUE (index_type)))
2932 /* If this node has a right branch, the value at the right must be greater
2933 than that at this node, so it cannot be bounded at the top and
2934 we need not bother testing any further. */
2939 high_plus_one = fold (build2 (PLUS_EXPR, TREE_TYPE (node->high),
2940 node->high, integer_one_node));
2942 /* If the addition above overflowed, we can't verify anything.
2943 Otherwise, look for a parent that tests our value + 1. */
2945 if (! tree_int_cst_lt (node->high, high_plus_one))
2948 for (pnode = node->parent; pnode; pnode = pnode->parent)
2949 if (tree_int_cst_equal (high_plus_one, pnode->low))
2955 /* Search the parent sections of the
2956 case node tree to see if both tests for the upper and lower
2957 bounds of NODE would be redundant. */
2960 node_is_bounded (case_node_ptr node, tree index_type)
2962 return (node_has_low_bound (node, index_type)
2963 && node_has_high_bound (node, index_type));
2966 /* Emit step-by-step code to select a case for the value of INDEX.
2967 The thus generated decision tree follows the form of the
2968 case-node binary tree NODE, whose nodes represent test conditions.
2969 INDEX_TYPE is the type of the index of the switch.
2971 Care is taken to prune redundant tests from the decision tree
2972 by detecting any boundary conditions already checked by
2973 emitted rtx. (See node_has_high_bound, node_has_low_bound
2974 and node_is_bounded, above.)
2976 Where the test conditions can be shown to be redundant we emit
2977 an unconditional jump to the target code. As a further
2978 optimization, the subordinates of a tree node are examined to
2979 check for bounded nodes. In this case conditional and/or
2980 unconditional jumps as a result of the boundary check for the
2981 current node are arranged to target the subordinates associated
2982 code for out of bound conditions on the current node.
2984 We can assume that when control reaches the code generated here,
2985 the index value has already been compared with the parents
2986 of this node, and determined to be on the same side of each parent
2987 as this node is. Thus, if this node tests for the value 51,
2988 and a parent tested for 52, we don't need to consider
2989 the possibility of a value greater than 51. If another parent
2990 tests for the value 50, then this node need not test anything. */
2993 emit_case_nodes (rtx index, case_node_ptr node, rtx default_label,
2996 /* If INDEX has an unsigned type, we must make unsigned branches. */
2997 int unsignedp = TYPE_UNSIGNED (index_type);
2998 enum machine_mode mode = GET_MODE (index);
2999 enum machine_mode imode = TYPE_MODE (index_type);
3001 /* See if our parents have already tested everything for us.
3002 If they have, emit an unconditional jump for this node. */
3003 if (node_is_bounded (node, index_type))
3004 emit_jump (label_rtx (node->code_label));
3006 else if (tree_int_cst_equal (node->low, node->high))
3008 /* Node is single valued. First see if the index expression matches
3009 this node and then check our children, if any. */
3011 do_jump_if_equal (index,
3012 convert_modes (mode, imode,
3013 expand_expr (node->low, NULL_RTX,
3016 label_rtx (node->code_label), unsignedp);
3018 if (node->right != 0 && node->left != 0)
3020 /* This node has children on both sides.
3021 Dispatch to one side or the other
3022 by comparing the index value with this node's value.
3023 If one subtree is bounded, check that one first,
3024 so we can avoid real branches in the tree. */
3026 if (node_is_bounded (node->right, index_type))
3028 emit_cmp_and_jump_insns (index,
3031 expand_expr (node->high, NULL_RTX,
3034 GT, NULL_RTX, mode, unsignedp,
3035 label_rtx (node->right->code_label));
3036 emit_case_nodes (index, node->left, default_label, index_type);
3039 else if (node_is_bounded (node->left, index_type))
3041 emit_cmp_and_jump_insns (index,
3044 expand_expr (node->high, NULL_RTX,
3047 LT, NULL_RTX, mode, unsignedp,
3048 label_rtx (node->left->code_label));
3049 emit_case_nodes (index, node->right, default_label, index_type);
3052 /* If both children are single-valued cases with no
3053 children, finish up all the work. This way, we can save
3054 one ordered comparison. */
3055 else if (tree_int_cst_equal (node->right->low, node->right->high)
3056 && node->right->left == 0
3057 && node->right->right == 0
3058 && tree_int_cst_equal (node->left->low, node->left->high)
3059 && node->left->left == 0
3060 && node->left->right == 0)
3062 /* Neither node is bounded. First distinguish the two sides;
3063 then emit the code for one side at a time. */
3065 /* See if the value matches what the right hand side
3067 do_jump_if_equal (index,
3068 convert_modes (mode, imode,
3069 expand_expr (node->right->low,
3073 label_rtx (node->right->code_label),
3076 /* See if the value matches what the left hand side
3078 do_jump_if_equal (index,
3079 convert_modes (mode, imode,
3080 expand_expr (node->left->low,
3084 label_rtx (node->left->code_label),
3090 /* Neither node is bounded. First distinguish the two sides;
3091 then emit the code for one side at a time. */
3093 tree test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
3095 /* See if the value is on the right. */
3096 emit_cmp_and_jump_insns (index,
3099 expand_expr (node->high, NULL_RTX,
3102 GT, NULL_RTX, mode, unsignedp,
3103 label_rtx (test_label));
3105 /* Value must be on the left.
3106 Handle the left-hand subtree. */
3107 emit_case_nodes (index, node->left, default_label, index_type);
3108 /* If left-hand subtree does nothing,
3110 emit_jump (default_label);
3112 /* Code branches here for the right-hand subtree. */
3113 expand_label (test_label);
3114 emit_case_nodes (index, node->right, default_label, index_type);
3118 else if (node->right != 0 && node->left == 0)
3120 /* Here we have a right child but no left so we issue conditional
3121 branch to default and process the right child.
3123 Omit the conditional branch to default if we it avoid only one
3124 right child; it costs too much space to save so little time. */
3126 if (node->right->right || node->right->left
3127 || !tree_int_cst_equal (node->right->low, node->right->high))
3129 if (!node_has_low_bound (node, index_type))
3131 emit_cmp_and_jump_insns (index,
3134 expand_expr (node->high, NULL_RTX,
3137 LT, NULL_RTX, mode, unsignedp,
3141 emit_case_nodes (index, node->right, default_label, index_type);
3144 /* We cannot process node->right normally
3145 since we haven't ruled out the numbers less than
3146 this node's value. So handle node->right explicitly. */
3147 do_jump_if_equal (index,
3150 expand_expr (node->right->low, NULL_RTX,
3153 label_rtx (node->right->code_label), unsignedp);
3156 else if (node->right == 0 && node->left != 0)
3158 /* Just one subtree, on the left. */
3159 if (node->left->left || node->left->right
3160 || !tree_int_cst_equal (node->left->low, node->left->high))
3162 if (!node_has_high_bound (node, index_type))
3164 emit_cmp_and_jump_insns (index,
3167 expand_expr (node->high, NULL_RTX,
3170 GT, NULL_RTX, mode, unsignedp,
3174 emit_case_nodes (index, node->left, default_label, index_type);
3177 /* We cannot process node->left normally
3178 since we haven't ruled out the numbers less than
3179 this node's value. So handle node->left explicitly. */
3180 do_jump_if_equal (index,
3183 expand_expr (node->left->low, NULL_RTX,
3186 label_rtx (node->left->code_label), unsignedp);
3191 /* Node is a range. These cases are very similar to those for a single
3192 value, except that we do not start by testing whether this node
3193 is the one to branch to. */
3195 if (node->right != 0 && node->left != 0)
3197 /* Node has subtrees on both sides.
3198 If the right-hand subtree is bounded,
3199 test for it first, since we can go straight there.
3200 Otherwise, we need to make a branch in the control structure,
3201 then handle the two subtrees. */
3202 tree test_label = 0;
3204 if (node_is_bounded (node->right, index_type))
3205 /* Right hand node is fully bounded so we can eliminate any
3206 testing and branch directly to the target code. */
3207 emit_cmp_and_jump_insns (index,
3210 expand_expr (node->high, NULL_RTX,
3213 GT, NULL_RTX, mode, unsignedp,
3214 label_rtx (node->right->code_label));
3217 /* Right hand node requires testing.
3218 Branch to a label where we will handle it later. */
3220 test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
3221 emit_cmp_and_jump_insns (index,
3224 expand_expr (node->high, NULL_RTX,
3227 GT, NULL_RTX, mode, unsignedp,
3228 label_rtx (test_label));
3231 /* Value belongs to this node or to the left-hand subtree. */
3233 emit_cmp_and_jump_insns (index,
3236 expand_expr (node->low, NULL_RTX,
3239 GE, NULL_RTX, mode, unsignedp,
3240 label_rtx (node->code_label));
3242 /* Handle the left-hand subtree. */
3243 emit_case_nodes (index, node->left, default_label, index_type);
3245 /* If right node had to be handled later, do that now. */
3249 /* If the left-hand subtree fell through,
3250 don't let it fall into the right-hand subtree. */
3251 emit_jump (default_label);
3253 expand_label (test_label);
3254 emit_case_nodes (index, node->right, default_label, index_type);
3258 else if (node->right != 0 && node->left == 0)
3260 /* Deal with values to the left of this node,
3261 if they are possible. */
3262 if (!node_has_low_bound (node, index_type))
3264 emit_cmp_and_jump_insns (index,
3267 expand_expr (node->low, NULL_RTX,
3270 LT, NULL_RTX, mode, unsignedp,
3274 /* Value belongs to this node or to the right-hand subtree. */
3276 emit_cmp_and_jump_insns (index,
3279 expand_expr (node->high, NULL_RTX,
3282 LE, NULL_RTX, mode, unsignedp,
3283 label_rtx (node->code_label));
3285 emit_case_nodes (index, node->right, default_label, index_type);
3288 else if (node->right == 0 && node->left != 0)
3290 /* Deal with values to the right of this node,
3291 if they are possible. */
3292 if (!node_has_high_bound (node, index_type))
3294 emit_cmp_and_jump_insns (index,
3297 expand_expr (node->high, NULL_RTX,
3300 GT, NULL_RTX, mode, unsignedp,
3304 /* Value belongs to this node or to the left-hand subtree. */
3306 emit_cmp_and_jump_insns (index,
3309 expand_expr (node->low, NULL_RTX,
3312 GE, NULL_RTX, mode, unsignedp,
3313 label_rtx (node->code_label));
3315 emit_case_nodes (index, node->left, default_label, index_type);
3320 /* Node has no children so we check low and high bounds to remove
3321 redundant tests. Only one of the bounds can exist,
3322 since otherwise this node is bounded--a case tested already. */
3323 int high_bound = node_has_high_bound (node, index_type);
3324 int low_bound = node_has_low_bound (node, index_type);
3326 if (!high_bound && low_bound)
3328 emit_cmp_and_jump_insns (index,
3331 expand_expr (node->high, NULL_RTX,
3334 GT, NULL_RTX, mode, unsignedp,
3338 else if (!low_bound && high_bound)
3340 emit_cmp_and_jump_insns (index,
3343 expand_expr (node->low, NULL_RTX,
3346 LT, NULL_RTX, mode, unsignedp,
3349 else if (!low_bound && !high_bound)
3351 /* Widen LOW and HIGH to the same width as INDEX. */
3352 tree type = lang_hooks.types.type_for_mode (mode, unsignedp);
3353 tree low = build1 (CONVERT_EXPR, type, node->low);
3354 tree high = build1 (CONVERT_EXPR, type, node->high);
3355 rtx low_rtx, new_index, new_bound;
3357 /* Instead of doing two branches, emit one unsigned branch for
3358 (index-low) > (high-low). */
3359 low_rtx = expand_expr (low, NULL_RTX, mode, 0);
3360 new_index = expand_simple_binop (mode, MINUS, index, low_rtx,
3361 NULL_RTX, unsignedp,
3363 new_bound = expand_expr (fold (build2 (MINUS_EXPR, type,
3367 emit_cmp_and_jump_insns (new_index, new_bound, GT, NULL_RTX,
3368 mode, 1, default_label);
3371 emit_jump (label_rtx (node->code_label));