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, 2005, 2006, 2007, 2008, 2009,
4 2010, 2011, 2012 Free Software Foundation, Inc.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 3, or (at your option) any later
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
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"
33 #include "hard-reg-set.h"
39 #include "insn-config.h"
44 #include "diagnostic-core.h"
47 #include "langhooks.h"
53 #include "alloc-pool.h"
54 #include "pretty-print.h"
59 /* Functions and data structures for expanding case statements. */
61 /* Case label structure, used to hold info on labels within case
62 statements. We handle "range" labels; for a single-value label
63 as in C, the high and low limits are the same.
65 We start with a vector of case nodes sorted in ascending order, and
66 the default label as the last element in the vector. Before expanding
67 to RTL, we transform this vector into a list linked via the RIGHT
68 fields in the case_node struct. Nodes with higher case values are
71 Switch statements can be output in three forms. A branch table is
72 used if there are more than a few labels and the labels are dense
73 within the range between the smallest and largest case value. If a
74 branch table is used, no further manipulations are done with the case
77 The alternative to the use of a branch table is to generate a series
78 of compare and jump insns. When that is done, we use the LEFT, RIGHT,
79 and PARENT fields to hold a binary tree. Initially the tree is
80 totally unbalanced, with everything on the right. We balance the tree
81 with nodes on the left having lower case values than the parent
82 and nodes on the right having higher values. We then output the tree
85 For very small, suitable switch statements, we can generate a series
86 of simple bit test and branches instead. */
90 struct case_node
*left
; /* Left son in binary tree */
91 struct case_node
*right
; /* Right son in binary tree; also node chain */
92 struct case_node
*parent
; /* Parent of node in binary tree */
93 tree low
; /* Lowest index value for this label */
94 tree high
; /* Highest index value for this label */
95 tree code_label
; /* Label to jump to when node matches */
98 typedef struct case_node case_node
;
99 typedef struct case_node
*case_node_ptr
;
102 static int n_occurrences (int, const char *);
103 static bool tree_conflicts_with_clobbers_p (tree
, HARD_REG_SET
*);
104 static void expand_nl_goto_receiver (void);
105 static bool check_operand_nalternatives (tree
, tree
);
106 static bool check_unique_operand_names (tree
, tree
, tree
);
107 static char *resolve_operand_name_1 (char *, tree
, tree
, tree
);
108 static void expand_null_return_1 (void);
109 static void expand_value_return (rtx
);
110 static bool lshift_cheap_p (void);
111 static int case_bit_test_cmp (const void *, const void *);
112 static void emit_case_bit_tests (tree
, tree
, tree
, tree
, case_node_ptr
, rtx
);
113 static void balance_case_nodes (case_node_ptr
*, case_node_ptr
);
114 static int node_has_low_bound (case_node_ptr
, tree
);
115 static int node_has_high_bound (case_node_ptr
, tree
);
116 static int node_is_bounded (case_node_ptr
, tree
);
117 static void emit_case_nodes (rtx
, case_node_ptr
, rtx
, tree
);
118 static struct case_node
*add_case_node (struct case_node
*, tree
,
119 tree
, tree
, tree
, alloc_pool
);
122 /* Return the rtx-label that corresponds to a LABEL_DECL,
123 creating it if necessary. */
126 label_rtx (tree label
)
128 gcc_assert (TREE_CODE (label
) == LABEL_DECL
);
130 if (!DECL_RTL_SET_P (label
))
132 rtx r
= gen_label_rtx ();
133 SET_DECL_RTL (label
, r
);
134 if (FORCED_LABEL (label
) || DECL_NONLOCAL (label
))
135 LABEL_PRESERVE_P (r
) = 1;
138 return DECL_RTL (label
);
141 /* As above, but also put it on the forced-reference list of the
142 function that contains it. */
144 force_label_rtx (tree label
)
146 rtx ref
= label_rtx (label
);
147 tree function
= decl_function_context (label
);
149 gcc_assert (function
);
151 forced_labels
= gen_rtx_EXPR_LIST (VOIDmode
, ref
, forced_labels
);
155 /* Add an unconditional jump to LABEL as the next sequential instruction. */
158 emit_jump (rtx label
)
160 do_pending_stack_adjust ();
161 emit_jump_insn (gen_jump (label
));
165 /* Emit code to jump to the address
166 specified by the pointer expression EXP. */
169 expand_computed_goto (tree exp
)
171 rtx x
= expand_normal (exp
);
173 x
= convert_memory_address (Pmode
, x
);
175 do_pending_stack_adjust ();
176 emit_indirect_jump (x
);
179 /* Handle goto statements and the labels that they can go to. */
181 /* Specify the location in the RTL code of a label LABEL,
182 which is a LABEL_DECL tree node.
184 This is used for the kind of label that the user can jump to with a
185 goto statement, and for alternatives of a switch or case statement.
186 RTL labels generated for loops and conditionals don't go through here;
187 they are generated directly at the RTL level, by other functions below.
189 Note that this has nothing to do with defining label *names*.
190 Languages vary in how they do that and what that even means. */
193 expand_label (tree label
)
195 rtx label_r
= label_rtx (label
);
197 do_pending_stack_adjust ();
198 emit_label (label_r
);
199 if (DECL_NAME (label
))
200 LABEL_NAME (DECL_RTL (label
)) = IDENTIFIER_POINTER (DECL_NAME (label
));
202 if (DECL_NONLOCAL (label
))
204 expand_nl_goto_receiver ();
205 nonlocal_goto_handler_labels
206 = gen_rtx_EXPR_LIST (VOIDmode
, label_r
,
207 nonlocal_goto_handler_labels
);
210 if (FORCED_LABEL (label
))
211 forced_labels
= gen_rtx_EXPR_LIST (VOIDmode
, label_r
, forced_labels
);
213 if (DECL_NONLOCAL (label
) || FORCED_LABEL (label
))
214 maybe_set_first_label_num (label_r
);
217 /* Generate RTL code for a `goto' statement with target label LABEL.
218 LABEL should be a LABEL_DECL tree node that was or will later be
219 defined with `expand_label'. */
222 expand_goto (tree label
)
224 #ifdef ENABLE_CHECKING
225 /* Check for a nonlocal goto to a containing function. Should have
226 gotten translated to __builtin_nonlocal_goto. */
227 tree context
= decl_function_context (label
);
228 gcc_assert (!context
|| context
== current_function_decl
);
231 emit_jump (label_rtx (label
));
234 /* Return the number of times character C occurs in string S. */
236 n_occurrences (int c
, const char *s
)
244 /* Generate RTL for an asm statement (explicit assembler code).
245 STRING is a STRING_CST node containing the assembler code text,
246 or an ADDR_EXPR containing a STRING_CST. VOL nonzero means the
247 insn is volatile; don't optimize it. */
250 expand_asm_loc (tree string
, int vol
, location_t locus
)
254 if (TREE_CODE (string
) == ADDR_EXPR
)
255 string
= TREE_OPERAND (string
, 0);
257 body
= gen_rtx_ASM_INPUT_loc (VOIDmode
,
258 ggc_strdup (TREE_STRING_POINTER (string
)),
261 MEM_VOLATILE_P (body
) = vol
;
266 /* Parse the output constraint pointed to by *CONSTRAINT_P. It is the
267 OPERAND_NUMth output operand, indexed from zero. There are NINPUTS
268 inputs and NOUTPUTS outputs to this extended-asm. Upon return,
269 *ALLOWS_MEM will be TRUE iff the constraint allows the use of a
270 memory operand. Similarly, *ALLOWS_REG will be TRUE iff the
271 constraint allows the use of a register operand. And, *IS_INOUT
272 will be true if the operand is read-write, i.e., if it is used as
273 an input as well as an output. If *CONSTRAINT_P is not in
274 canonical form, it will be made canonical. (Note that `+' will be
275 replaced with `=' as part of this process.)
277 Returns TRUE if all went well; FALSE if an error occurred. */
280 parse_output_constraint (const char **constraint_p
, int operand_num
,
281 int ninputs
, int noutputs
, bool *allows_mem
,
282 bool *allows_reg
, bool *is_inout
)
284 const char *constraint
= *constraint_p
;
287 /* Assume the constraint doesn't allow the use of either a register
292 /* Allow the `=' or `+' to not be at the beginning of the string,
293 since it wasn't explicitly documented that way, and there is a
294 large body of code that puts it last. Swap the character to
295 the front, so as not to uglify any place else. */
296 p
= strchr (constraint
, '=');
298 p
= strchr (constraint
, '+');
300 /* If the string doesn't contain an `=', issue an error
304 error ("output operand constraint lacks %<=%>");
308 /* If the constraint begins with `+', then the operand is both read
309 from and written to. */
310 *is_inout
= (*p
== '+');
312 /* Canonicalize the output constraint so that it begins with `='. */
313 if (p
!= constraint
|| *is_inout
)
316 size_t c_len
= strlen (constraint
);
319 warning (0, "output constraint %qc for operand %d "
320 "is not at the beginning",
323 /* Make a copy of the constraint. */
324 buf
= XALLOCAVEC (char, c_len
+ 1);
325 strcpy (buf
, constraint
);
326 /* Swap the first character and the `=' or `+'. */
327 buf
[p
- constraint
] = buf
[0];
328 /* Make sure the first character is an `='. (Until we do this,
329 it might be a `+'.) */
331 /* Replace the constraint with the canonicalized string. */
332 *constraint_p
= ggc_alloc_string (buf
, c_len
);
333 constraint
= *constraint_p
;
336 /* Loop through the constraint string. */
337 for (p
= constraint
+ 1; *p
; p
+= CONSTRAINT_LEN (*p
, p
))
342 error ("operand constraint contains incorrectly positioned "
347 if (operand_num
+ 1 == ninputs
+ noutputs
)
349 error ("%<%%%> constraint used with last operand");
354 case 'V': case TARGET_MEM_CONSTRAINT
: case 'o':
358 case '?': case '!': case '*': case '&': case '#':
359 case 'E': case 'F': case 'G': case 'H':
360 case 's': case 'i': case 'n':
361 case 'I': case 'J': case 'K': case 'L': case 'M':
362 case 'N': case 'O': case 'P': case ',':
365 case '0': case '1': case '2': case '3': case '4':
366 case '5': case '6': case '7': case '8': case '9':
368 error ("matching constraint not valid in output operand");
372 /* ??? Before flow, auto inc/dec insns are not supposed to exist,
373 excepting those that expand_call created. So match memory
390 if (REG_CLASS_FROM_CONSTRAINT (*p
, p
) != NO_REGS
)
392 #ifdef EXTRA_CONSTRAINT_STR
393 else if (EXTRA_ADDRESS_CONSTRAINT (*p
, p
))
395 else if (EXTRA_MEMORY_CONSTRAINT (*p
, p
))
399 /* Otherwise we can't assume anything about the nature of
400 the constraint except that it isn't purely registers.
401 Treat it like "g" and hope for the best. */
412 /* Similar, but for input constraints. */
415 parse_input_constraint (const char **constraint_p
, int input_num
,
416 int ninputs
, int noutputs
, int ninout
,
417 const char * const * constraints
,
418 bool *allows_mem
, bool *allows_reg
)
420 const char *constraint
= *constraint_p
;
421 const char *orig_constraint
= constraint
;
422 size_t c_len
= strlen (constraint
);
424 bool saw_match
= false;
426 /* Assume the constraint doesn't allow the use of either
427 a register or memory. */
431 /* Make sure constraint has neither `=', `+', nor '&'. */
433 for (j
= 0; j
< c_len
; j
+= CONSTRAINT_LEN (constraint
[j
], constraint
+j
))
434 switch (constraint
[j
])
436 case '+': case '=': case '&':
437 if (constraint
== orig_constraint
)
439 error ("input operand constraint contains %qc", constraint
[j
]);
445 if (constraint
== orig_constraint
446 && input_num
+ 1 == ninputs
- ninout
)
448 error ("%<%%%> constraint used with last operand");
453 case 'V': case TARGET_MEM_CONSTRAINT
: case 'o':
458 case '?': case '!': case '*': case '#':
459 case 'E': case 'F': case 'G': case 'H':
460 case 's': case 'i': case 'n':
461 case 'I': case 'J': case 'K': case 'L': case 'M':
462 case 'N': case 'O': case 'P': case ',':
465 /* Whether or not a numeric constraint allows a register is
466 decided by the matching constraint, and so there is no need
467 to do anything special with them. We must handle them in
468 the default case, so that we don't unnecessarily force
469 operands to memory. */
470 case '0': case '1': case '2': case '3': case '4':
471 case '5': case '6': case '7': case '8': case '9':
478 match
= strtoul (constraint
+ j
, &end
, 10);
479 if (match
>= (unsigned long) noutputs
)
481 error ("matching constraint references invalid operand number");
485 /* Try and find the real constraint for this dup. Only do this
486 if the matching constraint is the only alternative. */
488 && (j
== 0 || (j
== 1 && constraint
[0] == '%')))
490 constraint
= constraints
[match
];
491 *constraint_p
= constraint
;
492 c_len
= strlen (constraint
);
494 /* ??? At the end of the loop, we will skip the first part of
495 the matched constraint. This assumes not only that the
496 other constraint is an output constraint, but also that
497 the '=' or '+' come first. */
501 j
= end
- constraint
;
502 /* Anticipate increment at end of loop. */
517 if (! ISALPHA (constraint
[j
]))
519 error ("invalid punctuation %qc in constraint", constraint
[j
]);
522 if (REG_CLASS_FROM_CONSTRAINT (constraint
[j
], constraint
+ j
)
525 #ifdef EXTRA_CONSTRAINT_STR
526 else if (EXTRA_ADDRESS_CONSTRAINT (constraint
[j
], constraint
+ j
))
528 else if (EXTRA_MEMORY_CONSTRAINT (constraint
[j
], constraint
+ j
))
532 /* Otherwise we can't assume anything about the nature of
533 the constraint except that it isn't purely registers.
534 Treat it like "g" and hope for the best. */
542 if (saw_match
&& !*allows_reg
)
543 warning (0, "matching constraint does not allow a register");
548 /* Return DECL iff there's an overlap between *REGS and DECL, where DECL
549 can be an asm-declared register. Called via walk_tree. */
552 decl_overlaps_hard_reg_set_p (tree
*declp
, int *walk_subtrees ATTRIBUTE_UNUSED
,
556 const HARD_REG_SET
*const regs
= (const HARD_REG_SET
*) data
;
558 if (TREE_CODE (decl
) == VAR_DECL
)
560 if (DECL_HARD_REGISTER (decl
)
561 && REG_P (DECL_RTL (decl
))
562 && REGNO (DECL_RTL (decl
)) < FIRST_PSEUDO_REGISTER
)
564 rtx reg
= DECL_RTL (decl
);
566 if (overlaps_hard_reg_set_p (*regs
, GET_MODE (reg
), REGNO (reg
)))
571 else if (TYPE_P (decl
) || TREE_CODE (decl
) == PARM_DECL
)
576 /* If there is an overlap between *REGS and DECL, return the first overlap
579 tree_overlaps_hard_reg_set (tree decl
, HARD_REG_SET
*regs
)
581 return walk_tree (&decl
, decl_overlaps_hard_reg_set_p
, regs
, NULL
);
584 /* Check for overlap between registers marked in CLOBBERED_REGS and
585 anything inappropriate in T. Emit error and return the register
586 variable definition for error, NULL_TREE for ok. */
589 tree_conflicts_with_clobbers_p (tree t
, HARD_REG_SET
*clobbered_regs
)
591 /* Conflicts between asm-declared register variables and the clobber
592 list are not allowed. */
593 tree overlap
= tree_overlaps_hard_reg_set (t
, clobbered_regs
);
597 error ("asm-specifier for variable %qE conflicts with asm clobber list",
598 DECL_NAME (overlap
));
600 /* Reset registerness to stop multiple errors emitted for a single
602 DECL_REGISTER (overlap
) = 0;
609 /* Generate RTL for an asm statement with arguments.
610 STRING is the instruction template.
611 OUTPUTS is a list of output arguments (lvalues); INPUTS a list of inputs.
612 Each output or input has an expression in the TREE_VALUE and
613 a tree list in TREE_PURPOSE which in turn contains a constraint
614 name in TREE_VALUE (or NULL_TREE) and a constraint string
616 CLOBBERS is a list of STRING_CST nodes each naming a hard register
617 that is clobbered by this insn.
619 Not all kinds of lvalue that may appear in OUTPUTS can be stored directly.
620 Some elements of OUTPUTS may be replaced with trees representing temporary
621 values. The caller should copy those temporary values to the originally
624 VOL nonzero means the insn is volatile; don't optimize it. */
627 expand_asm_operands (tree string
, tree outputs
, tree inputs
,
628 tree clobbers
, tree labels
, int vol
, location_t locus
)
630 rtvec argvec
, constraintvec
, labelvec
;
632 int ninputs
= list_length (inputs
);
633 int noutputs
= list_length (outputs
);
634 int nlabels
= list_length (labels
);
637 HARD_REG_SET clobbered_regs
;
638 int clobber_conflict_found
= 0;
642 /* Vector of RTX's of evaluated output operands. */
643 rtx
*output_rtx
= XALLOCAVEC (rtx
, noutputs
);
644 int *inout_opnum
= XALLOCAVEC (int, noutputs
);
645 rtx
*real_output_rtx
= XALLOCAVEC (rtx
, noutputs
);
646 enum machine_mode
*inout_mode
= XALLOCAVEC (enum machine_mode
, noutputs
);
647 const char **constraints
= XALLOCAVEC (const char *, noutputs
+ ninputs
);
648 int old_generating_concat_p
= generating_concat_p
;
650 /* An ASM with no outputs needs to be treated as volatile, for now. */
654 if (! check_operand_nalternatives (outputs
, inputs
))
657 string
= resolve_asm_operand_names (string
, outputs
, inputs
, labels
);
659 /* Collect constraints. */
661 for (t
= outputs
; t
; t
= TREE_CHAIN (t
), i
++)
662 constraints
[i
] = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t
)));
663 for (t
= inputs
; t
; t
= TREE_CHAIN (t
), i
++)
664 constraints
[i
] = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t
)));
666 /* Sometimes we wish to automatically clobber registers across an asm.
667 Case in point is when the i386 backend moved from cc0 to a hard reg --
668 maintaining source-level compatibility means automatically clobbering
669 the flags register. */
670 clobbers
= targetm
.md_asm_clobbers (outputs
, inputs
, clobbers
);
672 /* Count the number of meaningful clobbered registers, ignoring what
673 we would ignore later. */
675 CLEAR_HARD_REG_SET (clobbered_regs
);
676 for (tail
= clobbers
; tail
; tail
= TREE_CHAIN (tail
))
681 if (TREE_VALUE (tail
) == error_mark_node
)
683 regname
= TREE_STRING_POINTER (TREE_VALUE (tail
));
685 i
= decode_reg_name_and_count (regname
, &nregs
);
689 error ("unknown register name %qs in %<asm%>", regname
);
691 /* Mark clobbered registers. */
696 for (reg
= i
; reg
< i
+ nregs
; reg
++)
700 /* Clobbering the PIC register is an error. */
701 if (reg
== (int) PIC_OFFSET_TABLE_REGNUM
)
703 error ("PIC register clobbered by %qs in %<asm%>", regname
);
707 SET_HARD_REG_BIT (clobbered_regs
, reg
);
712 /* First pass over inputs and outputs checks validity and sets
713 mark_addressable if needed. */
716 for (i
= 0, tail
= outputs
; tail
; tail
= TREE_CHAIN (tail
), i
++)
718 tree val
= TREE_VALUE (tail
);
719 tree type
= TREE_TYPE (val
);
720 const char *constraint
;
725 /* If there's an erroneous arg, emit no insn. */
726 if (type
== error_mark_node
)
729 /* Try to parse the output constraint. If that fails, there's
730 no point in going further. */
731 constraint
= constraints
[i
];
732 if (!parse_output_constraint (&constraint
, i
, ninputs
, noutputs
,
733 &allows_mem
, &allows_reg
, &is_inout
))
740 && REG_P (DECL_RTL (val
))
741 && GET_MODE (DECL_RTL (val
)) != TYPE_MODE (type
))))
742 mark_addressable (val
);
749 if (ninputs
+ noutputs
> MAX_RECOG_OPERANDS
)
751 error ("more than %d operands in %<asm%>", MAX_RECOG_OPERANDS
);
755 for (i
= 0, tail
= inputs
; tail
; i
++, tail
= TREE_CHAIN (tail
))
757 bool allows_reg
, allows_mem
;
758 const char *constraint
;
760 /* If there's an erroneous arg, emit no insn, because the ASM_INPUT
761 would get VOIDmode and that could cause a crash in reload. */
762 if (TREE_TYPE (TREE_VALUE (tail
)) == error_mark_node
)
765 constraint
= constraints
[i
+ noutputs
];
766 if (! parse_input_constraint (&constraint
, i
, ninputs
, noutputs
, ninout
,
767 constraints
, &allows_mem
, &allows_reg
))
770 if (! allows_reg
&& allows_mem
)
771 mark_addressable (TREE_VALUE (tail
));
774 /* Second pass evaluates arguments. */
776 /* Make sure stack is consistent for asm goto. */
778 do_pending_stack_adjust ();
781 for (i
= 0, tail
= outputs
; tail
; tail
= TREE_CHAIN (tail
), i
++)
783 tree val
= TREE_VALUE (tail
);
784 tree type
= TREE_TYPE (val
);
791 ok
= parse_output_constraint (&constraints
[i
], i
, ninputs
,
792 noutputs
, &allows_mem
, &allows_reg
,
796 /* If an output operand is not a decl or indirect ref and our constraint
797 allows a register, make a temporary to act as an intermediate.
798 Make the asm insn write into that, then our caller will copy it to
799 the real output operand. Likewise for promoted variables. */
801 generating_concat_p
= 0;
803 real_output_rtx
[i
] = NULL_RTX
;
804 if ((TREE_CODE (val
) == INDIRECT_REF
807 && (allows_mem
|| REG_P (DECL_RTL (val
)))
808 && ! (REG_P (DECL_RTL (val
))
809 && GET_MODE (DECL_RTL (val
)) != TYPE_MODE (type
)))
813 op
= expand_expr (val
, NULL_RTX
, VOIDmode
, EXPAND_WRITE
);
815 op
= validize_mem (op
);
817 if (! allows_reg
&& !MEM_P (op
))
818 error ("output number %d not directly addressable", i
);
819 if ((! allows_mem
&& MEM_P (op
))
820 || GET_CODE (op
) == CONCAT
)
822 real_output_rtx
[i
] = op
;
823 op
= gen_reg_rtx (GET_MODE (op
));
825 emit_move_insn (op
, real_output_rtx
[i
]);
830 op
= assign_temp (type
, 0, 0, 1);
831 op
= validize_mem (op
);
832 if (!MEM_P (op
) && TREE_CODE (TREE_VALUE (tail
)) == SSA_NAME
)
833 set_reg_attrs_for_decl_rtl (SSA_NAME_VAR (TREE_VALUE (tail
)), op
);
834 TREE_VALUE (tail
) = make_tree (type
, op
);
838 generating_concat_p
= old_generating_concat_p
;
842 inout_mode
[ninout
] = TYPE_MODE (type
);
843 inout_opnum
[ninout
++] = i
;
846 if (tree_conflicts_with_clobbers_p (val
, &clobbered_regs
))
847 clobber_conflict_found
= 1;
850 /* Make vectors for the expression-rtx, constraint strings,
851 and named operands. */
853 argvec
= rtvec_alloc (ninputs
);
854 constraintvec
= rtvec_alloc (ninputs
);
855 labelvec
= rtvec_alloc (nlabels
);
857 body
= gen_rtx_ASM_OPERANDS ((noutputs
== 0 ? VOIDmode
858 : GET_MODE (output_rtx
[0])),
859 ggc_strdup (TREE_STRING_POINTER (string
)),
860 empty_string
, 0, argvec
, constraintvec
,
863 MEM_VOLATILE_P (body
) = vol
;
865 /* Eval the inputs and put them into ARGVEC.
866 Put their constraints into ASM_INPUTs and store in CONSTRAINTS. */
868 for (i
= 0, tail
= inputs
; tail
; tail
= TREE_CHAIN (tail
), ++i
)
870 bool allows_reg
, allows_mem
;
871 const char *constraint
;
876 constraint
= constraints
[i
+ noutputs
];
877 ok
= parse_input_constraint (&constraint
, i
, ninputs
, noutputs
, ninout
,
878 constraints
, &allows_mem
, &allows_reg
);
881 generating_concat_p
= 0;
883 val
= TREE_VALUE (tail
);
884 type
= TREE_TYPE (val
);
885 /* EXPAND_INITIALIZER will not generate code for valid initializer
886 constants, but will still generate code for other types of operand.
887 This is the behavior we want for constant constraints. */
888 op
= expand_expr (val
, NULL_RTX
, VOIDmode
,
889 allows_reg
? EXPAND_NORMAL
890 : allows_mem
? EXPAND_MEMORY
891 : EXPAND_INITIALIZER
);
893 /* Never pass a CONCAT to an ASM. */
894 if (GET_CODE (op
) == CONCAT
)
895 op
= force_reg (GET_MODE (op
), op
);
897 op
= validize_mem (op
);
899 if (asm_operand_ok (op
, constraint
, NULL
) <= 0)
901 if (allows_reg
&& TYPE_MODE (type
) != BLKmode
)
902 op
= force_reg (TYPE_MODE (type
), op
);
903 else if (!allows_mem
)
904 warning (0, "asm operand %d probably doesn%'t match constraints",
908 /* We won't recognize either volatile memory or memory
909 with a queued address as available a memory_operand
910 at this point. Ignore it: clearly this *is* a memory. */
914 warning (0, "use of memory input without lvalue in "
915 "asm operand %d is deprecated", i
+ noutputs
);
919 rtx mem
= force_const_mem (TYPE_MODE (type
), op
);
921 op
= validize_mem (mem
);
923 op
= force_reg (TYPE_MODE (type
), op
);
926 || GET_CODE (op
) == SUBREG
927 || GET_CODE (op
) == CONCAT
)
929 tree qual_type
= build_qualified_type (type
,
932 rtx memloc
= assign_temp (qual_type
, 1, 1, 1);
933 memloc
= validize_mem (memloc
);
934 emit_move_insn (memloc
, op
);
940 generating_concat_p
= old_generating_concat_p
;
941 ASM_OPERANDS_INPUT (body
, i
) = op
;
943 ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body
, i
)
944 = gen_rtx_ASM_INPUT (TYPE_MODE (type
),
945 ggc_strdup (constraints
[i
+ noutputs
]));
947 if (tree_conflicts_with_clobbers_p (val
, &clobbered_regs
))
948 clobber_conflict_found
= 1;
951 /* Protect all the operands from the queue now that they have all been
954 generating_concat_p
= 0;
956 /* For in-out operands, copy output rtx to input rtx. */
957 for (i
= 0; i
< ninout
; i
++)
959 int j
= inout_opnum
[i
];
962 ASM_OPERANDS_INPUT (body
, ninputs
- ninout
+ i
)
965 sprintf (buffer
, "%d", j
);
966 ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body
, ninputs
- ninout
+ i
)
967 = gen_rtx_ASM_INPUT (inout_mode
[i
], ggc_strdup (buffer
));
970 /* Copy labels to the vector. */
971 for (i
= 0, tail
= labels
; i
< nlabels
; ++i
, tail
= TREE_CHAIN (tail
))
972 ASM_OPERANDS_LABEL (body
, i
)
973 = gen_rtx_LABEL_REF (Pmode
, label_rtx (TREE_VALUE (tail
)));
975 generating_concat_p
= old_generating_concat_p
;
977 /* Now, for each output, construct an rtx
978 (set OUTPUT (asm_operands INSN OUTPUTCONSTRAINT OUTPUTNUMBER
979 ARGVEC CONSTRAINTS OPNAMES))
980 If there is more than one, put them inside a PARALLEL. */
982 if (nlabels
> 0 && nclobbers
== 0)
984 gcc_assert (noutputs
== 0);
985 emit_jump_insn (body
);
987 else if (noutputs
== 0 && nclobbers
== 0)
989 /* No output operands: put in a raw ASM_OPERANDS rtx. */
992 else if (noutputs
== 1 && nclobbers
== 0)
994 ASM_OPERANDS_OUTPUT_CONSTRAINT (body
) = ggc_strdup (constraints
[0]);
995 emit_insn (gen_rtx_SET (VOIDmode
, output_rtx
[0], body
));
1005 body
= gen_rtx_PARALLEL (VOIDmode
, rtvec_alloc (num
+ nclobbers
));
1007 /* For each output operand, store a SET. */
1008 for (i
= 0, tail
= outputs
; tail
; tail
= TREE_CHAIN (tail
), i
++)
1010 XVECEXP (body
, 0, i
)
1011 = gen_rtx_SET (VOIDmode
,
1013 gen_rtx_ASM_OPERANDS
1014 (GET_MODE (output_rtx
[i
]),
1015 ggc_strdup (TREE_STRING_POINTER (string
)),
1016 ggc_strdup (constraints
[i
]),
1017 i
, argvec
, constraintvec
, labelvec
, locus
));
1019 MEM_VOLATILE_P (SET_SRC (XVECEXP (body
, 0, i
))) = vol
;
1022 /* If there are no outputs (but there are some clobbers)
1023 store the bare ASM_OPERANDS into the PARALLEL. */
1026 XVECEXP (body
, 0, i
++) = obody
;
1028 /* Store (clobber REG) for each clobbered register specified. */
1030 for (tail
= clobbers
; tail
; tail
= TREE_CHAIN (tail
))
1032 const char *regname
= TREE_STRING_POINTER (TREE_VALUE (tail
));
1034 int j
= decode_reg_name_and_count (regname
, &nregs
);
1039 if (j
== -3) /* `cc', which is not a register */
1042 if (j
== -4) /* `memory', don't cache memory across asm */
1044 XVECEXP (body
, 0, i
++)
1045 = gen_rtx_CLOBBER (VOIDmode
,
1048 gen_rtx_SCRATCH (VOIDmode
)));
1052 /* Ignore unknown register, error already signaled. */
1056 for (reg
= j
; reg
< j
+ nregs
; reg
++)
1058 /* Use QImode since that's guaranteed to clobber just
1060 clobbered_reg
= gen_rtx_REG (QImode
, reg
);
1062 /* Do sanity check for overlap between clobbers and
1063 respectively input and outputs that hasn't been
1064 handled. Such overlap should have been detected and
1066 if (!clobber_conflict_found
)
1070 /* We test the old body (obody) contents to avoid
1071 tripping over the under-construction body. */
1072 for (opno
= 0; opno
< noutputs
; opno
++)
1073 if (reg_overlap_mentioned_p (clobbered_reg
,
1076 ("asm clobber conflict with output operand");
1078 for (opno
= 0; opno
< ninputs
- ninout
; opno
++)
1079 if (reg_overlap_mentioned_p (clobbered_reg
,
1080 ASM_OPERANDS_INPUT (obody
,
1083 ("asm clobber conflict with input operand");
1086 XVECEXP (body
, 0, i
++)
1087 = gen_rtx_CLOBBER (VOIDmode
, clobbered_reg
);
1092 emit_jump_insn (body
);
1097 /* For any outputs that needed reloading into registers, spill them
1098 back to where they belong. */
1099 for (i
= 0; i
< noutputs
; ++i
)
1100 if (real_output_rtx
[i
])
1101 emit_move_insn (real_output_rtx
[i
], output_rtx
[i
]);
1103 crtl
->has_asm_statement
= 1;
1108 expand_asm_stmt (gimple stmt
)
1111 tree outputs
, tail
, t
;
1115 tree str
, out
, in
, cl
, labels
;
1116 location_t locus
= gimple_location (stmt
);
1118 /* Meh... convert the gimple asm operands into real tree lists.
1119 Eventually we should make all routines work on the vectors instead
1120 of relying on TREE_CHAIN. */
1122 n
= gimple_asm_noutputs (stmt
);
1125 t
= out
= gimple_asm_output_op (stmt
, 0);
1126 for (i
= 1; i
< n
; i
++)
1127 t
= TREE_CHAIN (t
) = gimple_asm_output_op (stmt
, i
);
1131 n
= gimple_asm_ninputs (stmt
);
1134 t
= in
= gimple_asm_input_op (stmt
, 0);
1135 for (i
= 1; i
< n
; i
++)
1136 t
= TREE_CHAIN (t
) = gimple_asm_input_op (stmt
, i
);
1140 n
= gimple_asm_nclobbers (stmt
);
1143 t
= cl
= gimple_asm_clobber_op (stmt
, 0);
1144 for (i
= 1; i
< n
; i
++)
1145 t
= TREE_CHAIN (t
) = gimple_asm_clobber_op (stmt
, i
);
1149 n
= gimple_asm_nlabels (stmt
);
1152 t
= labels
= gimple_asm_label_op (stmt
, 0);
1153 for (i
= 1; i
< n
; i
++)
1154 t
= TREE_CHAIN (t
) = gimple_asm_label_op (stmt
, i
);
1157 s
= gimple_asm_string (stmt
);
1158 str
= build_string (strlen (s
), s
);
1160 if (gimple_asm_input_p (stmt
))
1162 expand_asm_loc (str
, gimple_asm_volatile_p (stmt
), locus
);
1167 noutputs
= gimple_asm_noutputs (stmt
);
1168 /* o[I] is the place that output number I should be written. */
1169 o
= (tree
*) alloca (noutputs
* sizeof (tree
));
1171 /* Record the contents of OUTPUTS before it is modified. */
1172 for (i
= 0, tail
= outputs
; tail
; tail
= TREE_CHAIN (tail
), i
++)
1173 o
[i
] = TREE_VALUE (tail
);
1175 /* Generate the ASM_OPERANDS insn; store into the TREE_VALUEs of
1176 OUTPUTS some trees for where the values were actually stored. */
1177 expand_asm_operands (str
, outputs
, in
, cl
, labels
,
1178 gimple_asm_volatile_p (stmt
), locus
);
1180 /* Copy all the intermediate outputs into the specified outputs. */
1181 for (i
= 0, tail
= outputs
; tail
; tail
= TREE_CHAIN (tail
), i
++)
1183 if (o
[i
] != TREE_VALUE (tail
))
1185 expand_assignment (o
[i
], TREE_VALUE (tail
), false);
1188 /* Restore the original value so that it's correct the next
1189 time we expand this function. */
1190 TREE_VALUE (tail
) = o
[i
];
1195 /* A subroutine of expand_asm_operands. Check that all operands have
1196 the same number of alternatives. Return true if so. */
1199 check_operand_nalternatives (tree outputs
, tree inputs
)
1201 if (outputs
|| inputs
)
1203 tree tmp
= TREE_PURPOSE (outputs
? outputs
: inputs
);
1205 = n_occurrences (',', TREE_STRING_POINTER (TREE_VALUE (tmp
)));
1208 if (nalternatives
+ 1 > MAX_RECOG_ALTERNATIVES
)
1210 error ("too many alternatives in %<asm%>");
1217 const char *constraint
1218 = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tmp
)));
1220 if (n_occurrences (',', constraint
) != nalternatives
)
1222 error ("operand constraints for %<asm%> differ "
1223 "in number of alternatives");
1227 if (TREE_CHAIN (tmp
))
1228 tmp
= TREE_CHAIN (tmp
);
1230 tmp
= next
, next
= 0;
1237 /* A subroutine of expand_asm_operands. Check that all operand names
1238 are unique. Return true if so. We rely on the fact that these names
1239 are identifiers, and so have been canonicalized by get_identifier,
1240 so all we need are pointer comparisons. */
1243 check_unique_operand_names (tree outputs
, tree inputs
, tree labels
)
1245 tree i
, j
, i_name
= NULL_TREE
;
1247 for (i
= outputs
; i
; i
= TREE_CHAIN (i
))
1249 i_name
= TREE_PURPOSE (TREE_PURPOSE (i
));
1253 for (j
= TREE_CHAIN (i
); j
; j
= TREE_CHAIN (j
))
1254 if (simple_cst_equal (i_name
, TREE_PURPOSE (TREE_PURPOSE (j
))))
1258 for (i
= inputs
; i
; i
= TREE_CHAIN (i
))
1260 i_name
= TREE_PURPOSE (TREE_PURPOSE (i
));
1264 for (j
= TREE_CHAIN (i
); j
; j
= TREE_CHAIN (j
))
1265 if (simple_cst_equal (i_name
, TREE_PURPOSE (TREE_PURPOSE (j
))))
1267 for (j
= outputs
; j
; j
= TREE_CHAIN (j
))
1268 if (simple_cst_equal (i_name
, TREE_PURPOSE (TREE_PURPOSE (j
))))
1272 for (i
= labels
; i
; i
= TREE_CHAIN (i
))
1274 i_name
= TREE_PURPOSE (i
);
1278 for (j
= TREE_CHAIN (i
); j
; j
= TREE_CHAIN (j
))
1279 if (simple_cst_equal (i_name
, TREE_PURPOSE (j
)))
1281 for (j
= inputs
; j
; j
= TREE_CHAIN (j
))
1282 if (simple_cst_equal (i_name
, TREE_PURPOSE (TREE_PURPOSE (j
))))
1289 error ("duplicate asm operand name %qs", TREE_STRING_POINTER (i_name
));
1293 /* A subroutine of expand_asm_operands. Resolve the names of the operands
1294 in *POUTPUTS and *PINPUTS to numbers, and replace the name expansions in
1295 STRING and in the constraints to those numbers. */
1298 resolve_asm_operand_names (tree string
, tree outputs
, tree inputs
, tree labels
)
1305 check_unique_operand_names (outputs
, inputs
, labels
);
1307 /* Substitute [<name>] in input constraint strings. There should be no
1308 named operands in output constraints. */
1309 for (t
= inputs
; t
; t
= TREE_CHAIN (t
))
1311 c
= TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t
)));
1312 if (strchr (c
, '[') != NULL
)
1314 p
= buffer
= xstrdup (c
);
1315 while ((p
= strchr (p
, '[')) != NULL
)
1316 p
= resolve_operand_name_1 (p
, outputs
, inputs
, NULL
);
1317 TREE_VALUE (TREE_PURPOSE (t
))
1318 = build_string (strlen (buffer
), buffer
);
1323 /* Now check for any needed substitutions in the template. */
1324 c
= TREE_STRING_POINTER (string
);
1325 while ((c
= strchr (c
, '%')) != NULL
)
1329 else if (ISALPHA (c
[1]) && c
[2] == '[')
1333 c
+= 1 + (c
[1] == '%');
1340 /* OK, we need to make a copy so we can perform the substitutions.
1341 Assume that we will not need extra space--we get to remove '['
1342 and ']', which means we cannot have a problem until we have more
1343 than 999 operands. */
1344 buffer
= xstrdup (TREE_STRING_POINTER (string
));
1345 p
= buffer
+ (c
- TREE_STRING_POINTER (string
));
1347 while ((p
= strchr (p
, '%')) != NULL
)
1351 else if (ISALPHA (p
[1]) && p
[2] == '[')
1355 p
+= 1 + (p
[1] == '%');
1359 p
= resolve_operand_name_1 (p
, outputs
, inputs
, labels
);
1362 string
= build_string (strlen (buffer
), buffer
);
1369 /* A subroutine of resolve_operand_names. P points to the '[' for a
1370 potential named operand of the form [<name>]. In place, replace
1371 the name and brackets with a number. Return a pointer to the
1372 balance of the string after substitution. */
1375 resolve_operand_name_1 (char *p
, tree outputs
, tree inputs
, tree labels
)
1381 /* Collect the operand name. */
1382 q
= strchr (++p
, ']');
1385 error ("missing close brace for named operand");
1386 return strchr (p
, '\0');
1390 /* Resolve the name to a number. */
1391 for (op
= 0, t
= outputs
; t
; t
= TREE_CHAIN (t
), op
++)
1393 tree name
= TREE_PURPOSE (TREE_PURPOSE (t
));
1394 if (name
&& strcmp (TREE_STRING_POINTER (name
), p
) == 0)
1397 for (t
= inputs
; t
; t
= TREE_CHAIN (t
), op
++)
1399 tree name
= TREE_PURPOSE (TREE_PURPOSE (t
));
1400 if (name
&& strcmp (TREE_STRING_POINTER (name
), p
) == 0)
1403 for (t
= labels
; t
; t
= TREE_CHAIN (t
), op
++)
1405 tree name
= TREE_PURPOSE (t
);
1406 if (name
&& strcmp (TREE_STRING_POINTER (name
), p
) == 0)
1410 error ("undefined named operand %qs", identifier_to_locale (p
));
1414 /* Replace the name with the number. Unfortunately, not all libraries
1415 get the return value of sprintf correct, so search for the end of the
1416 generated string by hand. */
1417 sprintf (--p
, "%d", op
);
1418 p
= strchr (p
, '\0');
1420 /* Verify the no extra buffer space assumption. */
1421 gcc_assert (p
<= q
);
1423 /* Shift the rest of the buffer down to fill the gap. */
1424 memmove (p
, q
+ 1, strlen (q
+ 1) + 1);
1429 /* Generate RTL to evaluate the expression EXP. */
1432 expand_expr_stmt (tree exp
)
1437 value
= expand_expr (exp
, const0_rtx
, VOIDmode
, EXPAND_NORMAL
);
1438 type
= TREE_TYPE (exp
);
1440 /* If all we do is reference a volatile value in memory,
1441 copy it to a register to be sure it is actually touched. */
1442 if (value
&& MEM_P (value
) && TREE_THIS_VOLATILE (exp
))
1444 if (TYPE_MODE (type
) == VOIDmode
)
1446 else if (TYPE_MODE (type
) != BLKmode
)
1447 copy_to_reg (value
);
1450 rtx lab
= gen_label_rtx ();
1452 /* Compare the value with itself to reference it. */
1453 emit_cmp_and_jump_insns (value
, value
, EQ
,
1454 expand_normal (TYPE_SIZE (type
)),
1460 /* Free any temporaries used to evaluate this expression. */
1465 /* Generate RTL to return from the current function, with no value.
1466 (That is, we do not do anything about returning any value.) */
1469 expand_null_return (void)
1471 /* If this function was declared to return a value, but we
1472 didn't, clobber the return registers so that they are not
1473 propagated live to the rest of the function. */
1474 clobber_return_register ();
1476 expand_null_return_1 ();
1479 /* Generate RTL to return directly from the current function.
1480 (That is, we bypass any return value.) */
1483 expand_naked_return (void)
1487 clear_pending_stack_adjust ();
1488 do_pending_stack_adjust ();
1490 end_label
= naked_return_label
;
1492 end_label
= naked_return_label
= gen_label_rtx ();
1494 emit_jump (end_label
);
1497 /* Generate RTL to return from the current function, with value VAL. */
1500 expand_value_return (rtx val
)
1502 /* Copy the value to the return location unless it's already there. */
1504 tree decl
= DECL_RESULT (current_function_decl
);
1505 rtx return_reg
= DECL_RTL (decl
);
1506 if (return_reg
!= val
)
1508 tree funtype
= TREE_TYPE (current_function_decl
);
1509 tree type
= TREE_TYPE (decl
);
1510 int unsignedp
= TYPE_UNSIGNED (type
);
1511 enum machine_mode old_mode
= DECL_MODE (decl
);
1512 enum machine_mode mode
;
1513 if (DECL_BY_REFERENCE (decl
))
1514 mode
= promote_function_mode (type
, old_mode
, &unsignedp
, funtype
, 2);
1516 mode
= promote_function_mode (type
, old_mode
, &unsignedp
, funtype
, 1);
1518 if (mode
!= old_mode
)
1519 val
= convert_modes (mode
, old_mode
, val
, unsignedp
);
1521 if (GET_CODE (return_reg
) == PARALLEL
)
1522 emit_group_load (return_reg
, val
, type
, int_size_in_bytes (type
));
1524 emit_move_insn (return_reg
, val
);
1527 expand_null_return_1 ();
1530 /* Output a return with no value. */
1533 expand_null_return_1 (void)
1535 clear_pending_stack_adjust ();
1536 do_pending_stack_adjust ();
1537 emit_jump (return_label
);
1540 /* Generate RTL to evaluate the expression RETVAL and return it
1541 from the current function. */
1544 expand_return (tree retval
)
1550 /* If function wants no value, give it none. */
1551 if (TREE_CODE (TREE_TYPE (TREE_TYPE (current_function_decl
))) == VOID_TYPE
)
1553 expand_normal (retval
);
1554 expand_null_return ();
1558 if (retval
== error_mark_node
)
1560 /* Treat this like a return of no value from a function that
1562 expand_null_return ();
1565 else if ((TREE_CODE (retval
) == MODIFY_EXPR
1566 || TREE_CODE (retval
) == INIT_EXPR
)
1567 && TREE_CODE (TREE_OPERAND (retval
, 0)) == RESULT_DECL
)
1568 retval_rhs
= TREE_OPERAND (retval
, 1);
1570 retval_rhs
= retval
;
1572 result_rtl
= DECL_RTL (DECL_RESULT (current_function_decl
));
1574 /* If we are returning the RESULT_DECL, then the value has already
1575 been stored into it, so we don't have to do anything special. */
1576 if (TREE_CODE (retval_rhs
) == RESULT_DECL
)
1577 expand_value_return (result_rtl
);
1579 /* If the result is an aggregate that is being returned in one (or more)
1580 registers, load the registers here. */
1582 else if (retval_rhs
!= 0
1583 && TYPE_MODE (TREE_TYPE (retval_rhs
)) == BLKmode
1584 && REG_P (result_rtl
))
1586 val
= copy_blkmode_to_reg (GET_MODE (result_rtl
), retval_rhs
);
1589 /* Use the mode of the result value on the return register. */
1590 PUT_MODE (result_rtl
, GET_MODE (val
));
1591 expand_value_return (val
);
1594 expand_null_return ();
1596 else if (retval_rhs
!= 0
1597 && !VOID_TYPE_P (TREE_TYPE (retval_rhs
))
1598 && (REG_P (result_rtl
)
1599 || (GET_CODE (result_rtl
) == PARALLEL
)))
1601 /* Calculate the return value into a temporary (usually a pseudo
1603 tree ot
= TREE_TYPE (DECL_RESULT (current_function_decl
));
1604 tree nt
= build_qualified_type (ot
, TYPE_QUALS (ot
) | TYPE_QUAL_CONST
);
1606 val
= assign_temp (nt
, 0, 0, 1);
1607 val
= expand_expr (retval_rhs
, val
, GET_MODE (val
), EXPAND_NORMAL
);
1608 val
= force_not_mem (val
);
1609 /* Return the calculated value. */
1610 expand_value_return (val
);
1614 /* No hard reg used; calculate value into hard return reg. */
1615 expand_expr (retval
, const0_rtx
, VOIDmode
, EXPAND_NORMAL
);
1616 expand_value_return (result_rtl
);
1620 /* Emit code to restore vital registers at the beginning of a nonlocal goto
1623 expand_nl_goto_receiver (void)
1627 /* Clobber the FP when we get here, so we have to make sure it's
1628 marked as used by this function. */
1629 emit_use (hard_frame_pointer_rtx
);
1631 /* Mark the static chain as clobbered here so life information
1632 doesn't get messed up for it. */
1633 chain
= targetm
.calls
.static_chain (current_function_decl
, true);
1634 if (chain
&& REG_P (chain
))
1635 emit_clobber (chain
);
1637 #ifdef HAVE_nonlocal_goto
1638 if (! HAVE_nonlocal_goto
)
1640 /* First adjust our frame pointer to its actual value. It was
1641 previously set to the start of the virtual area corresponding to
1642 the stacked variables when we branched here and now needs to be
1643 adjusted to the actual hardware fp value.
1645 Assignments are to virtual registers are converted by
1646 instantiate_virtual_regs into the corresponding assignment
1647 to the underlying register (fp in this case) that makes
1648 the original assignment true.
1649 So the following insn will actually be
1650 decrementing fp by STARTING_FRAME_OFFSET. */
1651 emit_move_insn (virtual_stack_vars_rtx
, hard_frame_pointer_rtx
);
1653 #if !HARD_FRAME_POINTER_IS_ARG_POINTER
1654 if (fixed_regs
[ARG_POINTER_REGNUM
])
1656 #ifdef ELIMINABLE_REGS
1657 /* If the argument pointer can be eliminated in favor of the
1658 frame pointer, we don't need to restore it. We assume here
1659 that if such an elimination is present, it can always be used.
1660 This is the case on all known machines; if we don't make this
1661 assumption, we do unnecessary saving on many machines. */
1662 static const struct elims
{const int from
, to
;} elim_regs
[] = ELIMINABLE_REGS
;
1665 for (i
= 0; i
< ARRAY_SIZE (elim_regs
); i
++)
1666 if (elim_regs
[i
].from
== ARG_POINTER_REGNUM
1667 && elim_regs
[i
].to
== HARD_FRAME_POINTER_REGNUM
)
1670 if (i
== ARRAY_SIZE (elim_regs
))
1673 /* Now restore our arg pointer from the address at which it
1674 was saved in our stack frame. */
1675 emit_move_insn (crtl
->args
.internal_arg_pointer
,
1676 copy_to_reg (get_arg_pointer_save_area ()));
1681 #ifdef HAVE_nonlocal_goto_receiver
1682 if (HAVE_nonlocal_goto_receiver
)
1683 emit_insn (gen_nonlocal_goto_receiver ());
1686 /* We must not allow the code we just generated to be reordered by
1687 scheduling. Specifically, the update of the frame pointer must
1688 happen immediately, not later. */
1689 emit_insn (gen_blockage ());
1692 /* Generate RTL for the automatic variable declaration DECL.
1693 (Other kinds of declarations are simply ignored if seen here.) */
1696 expand_decl (tree decl
)
1700 type
= TREE_TYPE (decl
);
1702 /* For a CONST_DECL, set mode, alignment, and sizes from those of the
1703 type in case this node is used in a reference. */
1704 if (TREE_CODE (decl
) == CONST_DECL
)
1706 DECL_MODE (decl
) = TYPE_MODE (type
);
1707 DECL_ALIGN (decl
) = TYPE_ALIGN (type
);
1708 DECL_SIZE (decl
) = TYPE_SIZE (type
);
1709 DECL_SIZE_UNIT (decl
) = TYPE_SIZE_UNIT (type
);
1713 /* Otherwise, only automatic variables need any expansion done. Static and
1714 external variables, and external functions, will be handled by
1715 `assemble_variable' (called from finish_decl). TYPE_DECL requires
1716 nothing. PARM_DECLs are handled in `assign_parms'. */
1717 if (TREE_CODE (decl
) != VAR_DECL
)
1720 if (TREE_STATIC (decl
) || DECL_EXTERNAL (decl
))
1723 /* Create the RTL representation for the variable. */
1725 if (type
== error_mark_node
)
1726 SET_DECL_RTL (decl
, gen_rtx_MEM (BLKmode
, const0_rtx
));
1728 else if (DECL_SIZE (decl
) == 0)
1730 /* Variable with incomplete type. */
1732 if (DECL_INITIAL (decl
) == 0)
1733 /* Error message was already done; now avoid a crash. */
1734 x
= gen_rtx_MEM (BLKmode
, const0_rtx
);
1736 /* An initializer is going to decide the size of this array.
1737 Until we know the size, represent its address with a reg. */
1738 x
= gen_rtx_MEM (BLKmode
, gen_reg_rtx (Pmode
));
1740 set_mem_attributes (x
, decl
, 1);
1741 SET_DECL_RTL (decl
, x
);
1743 else if (use_register_for_decl (decl
))
1745 /* Automatic variable that can go in a register. */
1746 enum machine_mode reg_mode
= promote_decl_mode (decl
, NULL
);
1748 SET_DECL_RTL (decl
, gen_reg_rtx (reg_mode
));
1750 /* Note if the object is a user variable. */
1751 if (!DECL_ARTIFICIAL (decl
))
1752 mark_user_reg (DECL_RTL (decl
));
1754 if (POINTER_TYPE_P (type
))
1755 mark_reg_pointer (DECL_RTL (decl
),
1756 TYPE_ALIGN (TREE_TYPE (TREE_TYPE (decl
))));
1765 /* Variable-sized decls are dealt with in the gimplifier. */
1766 gcc_assert (TREE_CODE (DECL_SIZE_UNIT (decl
)) == INTEGER_CST
);
1768 /* If we previously made RTL for this decl, it must be an array
1769 whose size was determined by the initializer.
1770 The old address was a register; set that register now
1771 to the proper address. */
1772 if (DECL_RTL_SET_P (decl
))
1774 gcc_assert (MEM_P (DECL_RTL (decl
)));
1775 gcc_assert (REG_P (XEXP (DECL_RTL (decl
), 0)));
1776 oldaddr
= XEXP (DECL_RTL (decl
), 0);
1779 /* Set alignment we actually gave this decl. */
1780 DECL_ALIGN (decl
) = (DECL_MODE (decl
) == BLKmode
? BIGGEST_ALIGNMENT
1781 : GET_MODE_BITSIZE (DECL_MODE (decl
)));
1782 DECL_USER_ALIGN (decl
) = 0;
1784 x
= assign_temp (decl
, 1, 1, 1);
1785 set_mem_attributes (x
, decl
, 1);
1786 SET_DECL_RTL (decl
, x
);
1790 addr
= force_operand (XEXP (DECL_RTL (decl
), 0), oldaddr
);
1791 if (addr
!= oldaddr
)
1792 emit_move_insn (oldaddr
, addr
);
1797 /* Emit code to save the current value of stack. */
1799 expand_stack_save (void)
1803 do_pending_stack_adjust ();
1804 emit_stack_save (SAVE_BLOCK
, &ret
);
1808 /* Emit code to restore the current value of stack. */
1810 expand_stack_restore (tree var
)
1812 rtx prev
, sa
= expand_normal (var
);
1814 sa
= convert_memory_address (Pmode
, sa
);
1816 prev
= get_last_insn ();
1817 emit_stack_restore (SAVE_BLOCK
, sa
);
1818 fixup_args_size_notes (prev
, get_last_insn (), 0);
1821 /* Do the insertion of a case label into case_list. The labels are
1822 fed to us in descending order from the sorted vector of case labels used
1823 in the tree part of the middle end. So the list we construct is
1824 sorted in ascending order. The bounds on the case range, LOW and HIGH,
1825 are converted to case's index type TYPE. */
1827 static struct case_node
*
1828 add_case_node (struct case_node
*head
, tree type
, tree low
, tree high
,
1829 tree label
, alloc_pool case_node_pool
)
1831 tree min_value
, max_value
;
1832 struct case_node
*r
;
1834 gcc_assert (TREE_CODE (low
) == INTEGER_CST
);
1835 gcc_assert (!high
|| TREE_CODE (high
) == INTEGER_CST
);
1837 min_value
= TYPE_MIN_VALUE (type
);
1838 max_value
= TYPE_MAX_VALUE (type
);
1840 /* If there's no HIGH value, then this is not a case range; it's
1841 just a simple case label. But that's just a degenerate case
1843 If the bounds are equal, turn this into the one-value case. */
1844 if (!high
|| tree_int_cst_equal (low
, high
))
1846 /* If the simple case value is unreachable, ignore it. */
1847 if ((TREE_CODE (min_value
) == INTEGER_CST
1848 && tree_int_cst_compare (low
, min_value
) < 0)
1849 || (TREE_CODE (max_value
) == INTEGER_CST
1850 && tree_int_cst_compare (low
, max_value
) > 0))
1852 low
= fold_convert (type
, low
);
1857 /* If the entire case range is unreachable, ignore it. */
1858 if ((TREE_CODE (min_value
) == INTEGER_CST
1859 && tree_int_cst_compare (high
, min_value
) < 0)
1860 || (TREE_CODE (max_value
) == INTEGER_CST
1861 && tree_int_cst_compare (low
, max_value
) > 0))
1864 /* If the lower bound is less than the index type's minimum
1865 value, truncate the range bounds. */
1866 if (TREE_CODE (min_value
) == INTEGER_CST
1867 && tree_int_cst_compare (low
, min_value
) < 0)
1869 low
= fold_convert (type
, low
);
1871 /* If the upper bound is greater than the index type's maximum
1872 value, truncate the range bounds. */
1873 if (TREE_CODE (max_value
) == INTEGER_CST
1874 && tree_int_cst_compare (high
, max_value
) > 0)
1876 high
= fold_convert (type
, high
);
1880 /* Add this label to the chain. Make sure to drop overflow flags. */
1881 r
= (struct case_node
*) pool_alloc (case_node_pool
);
1882 r
->low
= build_int_cst_wide (TREE_TYPE (low
), TREE_INT_CST_LOW (low
),
1883 TREE_INT_CST_HIGH (low
));
1884 r
->high
= build_int_cst_wide (TREE_TYPE (high
), TREE_INT_CST_LOW (high
),
1885 TREE_INT_CST_HIGH (high
));
1886 r
->code_label
= label
;
1887 r
->parent
= r
->left
= NULL
;
1892 /* Maximum number of case bit tests. */
1893 #define MAX_CASE_BIT_TESTS 3
1895 /* By default, enable case bit tests on targets with ashlsi3. */
1896 #ifndef CASE_USE_BIT_TESTS
1897 #define CASE_USE_BIT_TESTS (optab_handler (ashl_optab, word_mode) \
1898 != CODE_FOR_nothing)
1902 /* A case_bit_test represents a set of case nodes that may be
1903 selected from using a bit-wise comparison. HI and LO hold
1904 the integer to be tested against, LABEL contains the label
1905 to jump to upon success and BITS counts the number of case
1906 nodes handled by this test, typically the number of bits
1909 struct case_bit_test
1917 /* Determine whether "1 << x" is relatively cheap in word_mode. */
1920 bool lshift_cheap_p (void)
1922 static bool init
[2] = {false, false};
1923 static bool cheap
[2] = {true, true};
1925 bool speed_p
= optimize_insn_for_speed_p ();
1929 rtx reg
= gen_rtx_REG (word_mode
, 10000);
1930 int cost
= set_src_cost (gen_rtx_ASHIFT (word_mode
, const1_rtx
, reg
),
1932 cheap
[speed_p
] = cost
< COSTS_N_INSNS (3);
1933 init
[speed_p
] = true;
1936 return cheap
[speed_p
];
1939 /* Comparison function for qsort to order bit tests by decreasing
1940 number of case nodes, i.e. the node with the most cases gets
1944 case_bit_test_cmp (const void *p1
, const void *p2
)
1946 const struct case_bit_test
*const d1
= (const struct case_bit_test
*) p1
;
1947 const struct case_bit_test
*const d2
= (const struct case_bit_test
*) p2
;
1949 if (d2
->bits
!= d1
->bits
)
1950 return d2
->bits
- d1
->bits
;
1952 /* Stabilize the sort. */
1953 return CODE_LABEL_NUMBER (d2
->label
) - CODE_LABEL_NUMBER (d1
->label
);
1956 /* Expand a switch statement by a short sequence of bit-wise
1957 comparisons. "switch(x)" is effectively converted into
1958 "if ((1 << (x-MINVAL)) & CST)" where CST and MINVAL are
1961 INDEX_EXPR is the value being switched on, which is of
1962 type INDEX_TYPE. MINVAL is the lowest case value of in
1963 the case nodes, of INDEX_TYPE type, and RANGE is highest
1964 value minus MINVAL, also of type INDEX_TYPE. NODES is
1965 the set of case nodes, and DEFAULT_LABEL is the label to
1966 branch to should none of the cases match.
1968 There *MUST* be MAX_CASE_BIT_TESTS or less unique case
1972 emit_case_bit_tests (tree index_type
, tree index_expr
, tree minval
,
1973 tree range
, case_node_ptr nodes
, rtx default_label
)
1975 struct case_bit_test test
[MAX_CASE_BIT_TESTS
];
1976 enum machine_mode mode
;
1977 rtx expr
, index
, label
;
1978 unsigned int i
,j
,lo
,hi
;
1979 struct case_node
*n
;
1983 for (n
= nodes
; n
; n
= n
->right
)
1985 label
= label_rtx (n
->code_label
);
1986 for (i
= 0; i
< count
; i
++)
1987 if (label
== test
[i
].label
)
1992 gcc_assert (count
< MAX_CASE_BIT_TESTS
);
1995 test
[i
].label
= label
;
2002 lo
= tree_low_cst (fold_build2 (MINUS_EXPR
, index_type
,
2003 n
->low
, minval
), 1);
2004 hi
= tree_low_cst (fold_build2 (MINUS_EXPR
, index_type
,
2005 n
->high
, minval
), 1);
2006 for (j
= lo
; j
<= hi
; j
++)
2007 if (j
>= HOST_BITS_PER_WIDE_INT
)
2008 test
[i
].hi
|= (HOST_WIDE_INT
) 1 << (j
- HOST_BITS_PER_INT
);
2010 test
[i
].lo
|= (HOST_WIDE_INT
) 1 << j
;
2013 qsort (test
, count
, sizeof(*test
), case_bit_test_cmp
);
2015 index_expr
= fold_build2 (MINUS_EXPR
, index_type
,
2016 fold_convert (index_type
, index_expr
),
2017 fold_convert (index_type
, minval
));
2018 index
= expand_normal (index_expr
);
2019 do_pending_stack_adjust ();
2021 mode
= TYPE_MODE (index_type
);
2022 expr
= expand_normal (range
);
2024 emit_cmp_and_jump_insns (index
, expr
, GTU
, NULL_RTX
, mode
, 1,
2027 index
= convert_to_mode (word_mode
, index
, 0);
2028 index
= expand_binop (word_mode
, ashl_optab
, const1_rtx
,
2029 index
, NULL_RTX
, 1, OPTAB_WIDEN
);
2031 for (i
= 0; i
< count
; i
++)
2033 expr
= immed_double_const (test
[i
].lo
, test
[i
].hi
, word_mode
);
2034 expr
= expand_binop (word_mode
, and_optab
, index
, expr
,
2035 NULL_RTX
, 1, OPTAB_WIDEN
);
2036 emit_cmp_and_jump_insns (expr
, const0_rtx
, NE
, NULL_RTX
,
2037 word_mode
, 1, test
[i
].label
);
2041 emit_jump (default_label
);
2045 #define HAVE_casesi 0
2048 #ifndef HAVE_tablejump
2049 #define HAVE_tablejump 0
2052 /* Return true if a switch should be expanded as a bit test.
2053 INDEX_EXPR is the index expression, RANGE is the difference between
2054 highest and lowest case, UNIQ is number of unique case node targets
2055 not counting the default case and COUNT is the number of comparisons
2056 needed, not counting the default case. */
2058 expand_switch_using_bit_tests_p (tree index_expr
, tree range
,
2059 unsigned int uniq
, unsigned int count
)
2061 return (CASE_USE_BIT_TESTS
2062 && ! TREE_CONSTANT (index_expr
)
2063 && compare_tree_int (range
, GET_MODE_BITSIZE (word_mode
)) < 0
2064 && compare_tree_int (range
, 0) > 0
2065 && lshift_cheap_p ()
2066 && ((uniq
== 1 && count
>= 3)
2067 || (uniq
== 2 && count
>= 5)
2068 || (uniq
== 3 && count
>= 6)));
2071 /* Return the smallest number of different values for which it is best to use a
2072 jump-table instead of a tree of conditional branches. */
2075 case_values_threshold (void)
2077 unsigned int threshold
= PARAM_VALUE (PARAM_CASE_VALUES_THRESHOLD
);
2080 threshold
= targetm
.case_values_threshold ();
2085 /* Terminate a case (Pascal/Ada) or switch (C) statement
2086 in which ORIG_INDEX is the expression to be tested.
2087 If ORIG_TYPE is not NULL, it is the original ORIG_INDEX
2088 type as given in the source before any compiler conversions.
2089 Generate the code to test it and jump to the right place. */
2092 expand_case (gimple stmt
)
2094 tree minval
= NULL_TREE
, maxval
= NULL_TREE
, range
= NULL_TREE
;
2095 rtx default_label
= 0;
2096 struct case_node
*n
;
2097 unsigned int count
, uniq
;
2103 rtx before_case
, end
, lab
;
2105 tree index_expr
= gimple_switch_index (stmt
);
2106 tree index_type
= TREE_TYPE (index_expr
);
2107 int unsignedp
= TYPE_UNSIGNED (index_type
);
2109 /* The insn after which the case dispatch should finally
2110 be emitted. Zero for a dummy. */
2113 /* A list of case labels; it is first built as a list and it may then
2114 be rearranged into a nearly balanced binary tree. */
2115 struct case_node
*case_list
= 0;
2117 /* Label to jump to if no case matches. */
2118 tree default_label_decl
= NULL_TREE
;
2120 alloc_pool case_node_pool
= create_alloc_pool ("struct case_node pool",
2121 sizeof (struct case_node
),
2124 do_pending_stack_adjust ();
2126 /* An ERROR_MARK occurs for various reasons including invalid data type. */
2127 if (index_type
!= error_mark_node
)
2130 bitmap label_bitmap
;
2133 /* cleanup_tree_cfg removes all SWITCH_EXPR with their index
2134 expressions being INTEGER_CST. */
2135 gcc_assert (TREE_CODE (index_expr
) != INTEGER_CST
);
2137 /* The default case, if ever taken, is the first element. */
2138 elt
= gimple_switch_label (stmt
, 0);
2139 if (!CASE_LOW (elt
) && !CASE_HIGH (elt
))
2141 default_label_decl
= CASE_LABEL (elt
);
2145 for (i
= gimple_switch_num_labels (stmt
) - 1; i
>= stopi
; --i
)
2148 elt
= gimple_switch_label (stmt
, i
);
2150 low
= CASE_LOW (elt
);
2152 high
= CASE_HIGH (elt
);
2154 /* Discard empty ranges. */
2155 if (high
&& tree_int_cst_lt (high
, low
))
2158 case_list
= add_case_node (case_list
, index_type
, low
, high
,
2159 CASE_LABEL (elt
), case_node_pool
);
2163 before_case
= start
= get_last_insn ();
2164 if (default_label_decl
)
2165 default_label
= label_rtx (default_label_decl
);
2167 /* Get upper and lower bounds of case values. */
2171 label_bitmap
= BITMAP_ALLOC (NULL
);
2172 for (n
= case_list
; n
; n
= n
->right
)
2174 /* Count the elements and track the largest and smallest
2175 of them (treating them as signed even if they are not). */
2183 if (tree_int_cst_lt (n
->low
, minval
))
2185 if (tree_int_cst_lt (maxval
, n
->high
))
2188 /* A range counts double, since it requires two compares. */
2189 if (! tree_int_cst_equal (n
->low
, n
->high
))
2192 /* If we have not seen this label yet, then increase the
2193 number of unique case node targets seen. */
2194 lab
= label_rtx (n
->code_label
);
2195 if (bitmap_set_bit (label_bitmap
, CODE_LABEL_NUMBER (lab
)))
2199 BITMAP_FREE (label_bitmap
);
2201 /* cleanup_tree_cfg removes all SWITCH_EXPR with a single
2202 destination, such as one with a default case only. However,
2203 it doesn't remove cases that are out of range for the switch
2204 type, so we may still get a zero here. */
2208 emit_jump (default_label
);
2209 free_alloc_pool (case_node_pool
);
2213 /* Compute span of values. */
2214 range
= fold_build2 (MINUS_EXPR
, index_type
, maxval
, minval
);
2216 /* Try implementing this switch statement by a short sequence of
2217 bit-wise comparisons. However, we let the binary-tree case
2218 below handle constant index expressions. */
2219 if (expand_switch_using_bit_tests_p (index_expr
, range
, uniq
, count
))
2221 /* Optimize the case where all the case values fit in a
2222 word without having to subtract MINVAL. In this case,
2223 we can optimize away the subtraction. */
2224 if (compare_tree_int (minval
, 0) > 0
2225 && compare_tree_int (maxval
, GET_MODE_BITSIZE (word_mode
)) < 0)
2227 minval
= build_int_cst (index_type
, 0);
2230 emit_case_bit_tests (index_type
, index_expr
, minval
, range
,
2231 case_list
, default_label
);
2234 /* If range of values is much bigger than number of values,
2235 make a sequence of conditional branches instead of a dispatch.
2236 If the switch-index is a constant, do it this way
2237 because we can optimize it. */
2239 else if (count
< case_values_threshold ()
2240 || compare_tree_int (range
,
2241 (optimize_insn_for_size_p () ? 3 : 10) * count
) > 0
2242 /* RANGE may be signed, and really large ranges will show up
2243 as negative numbers. */
2244 || compare_tree_int (range
, 0) < 0
2245 #ifndef ASM_OUTPUT_ADDR_DIFF_ELT
2248 || !flag_jump_tables
2249 || TREE_CONSTANT (index_expr
)
2250 /* If neither casesi or tablejump is available, we can
2251 only go this way. */
2252 || (!HAVE_casesi
&& !HAVE_tablejump
))
2254 index
= expand_normal (index_expr
);
2256 /* If the index is a short or char that we do not have
2257 an insn to handle comparisons directly, convert it to
2258 a full integer now, rather than letting each comparison
2259 generate the conversion. */
2261 if (GET_MODE_CLASS (GET_MODE (index
)) == MODE_INT
2262 && ! have_insn_for (COMPARE
, GET_MODE (index
)))
2264 enum machine_mode wider_mode
;
2265 for (wider_mode
= GET_MODE (index
); wider_mode
!= VOIDmode
;
2266 wider_mode
= GET_MODE_WIDER_MODE (wider_mode
))
2267 if (have_insn_for (COMPARE
, wider_mode
))
2269 index
= convert_to_mode (wider_mode
, index
, unsignedp
);
2274 do_pending_stack_adjust ();
2278 index
= copy_to_reg (index
);
2279 if (TREE_CODE (index_expr
) == SSA_NAME
)
2280 set_reg_attrs_for_decl_rtl (SSA_NAME_VAR (index_expr
), index
);
2283 /* We generate a binary decision tree to select the
2284 appropriate target code. This is done as follows:
2286 The list of cases is rearranged into a binary tree,
2287 nearly optimal assuming equal probability for each case.
2289 The tree is transformed into RTL, eliminating
2290 redundant test conditions at the same time.
2292 If program flow could reach the end of the
2293 decision tree an unconditional jump to the
2294 default code is emitted. */
2296 balance_case_nodes (&case_list
, NULL
);
2297 emit_case_nodes (index
, case_list
, default_label
, index_type
);
2299 emit_jump (default_label
);
2303 rtx fallback_label
= label_rtx (case_list
->code_label
);
2304 table_label
= gen_label_rtx ();
2305 if (! try_casesi (index_type
, index_expr
, minval
, range
,
2306 table_label
, default_label
, fallback_label
))
2310 /* Index jumptables from zero for suitable values of
2311 minval to avoid a subtraction. */
2312 if (optimize_insn_for_speed_p ()
2313 && compare_tree_int (minval
, 0) > 0
2314 && compare_tree_int (minval
, 3) < 0)
2316 minval
= build_int_cst (index_type
, 0);
2320 ok
= try_tablejump (index_type
, index_expr
, minval
, range
,
2321 table_label
, default_label
);
2325 /* Get table of labels to jump to, in order of case index. */
2327 ncases
= tree_low_cst (range
, 0) + 1;
2328 labelvec
= XALLOCAVEC (rtx
, ncases
);
2329 memset (labelvec
, 0, ncases
* sizeof (rtx
));
2331 for (n
= case_list
; n
; n
= n
->right
)
2333 /* Compute the low and high bounds relative to the minimum
2334 value since that should fit in a HOST_WIDE_INT while the
2335 actual values may not. */
2337 = tree_low_cst (fold_build2 (MINUS_EXPR
, index_type
,
2338 n
->low
, minval
), 1);
2339 HOST_WIDE_INT i_high
2340 = tree_low_cst (fold_build2 (MINUS_EXPR
, index_type
,
2341 n
->high
, minval
), 1);
2344 for (i
= i_low
; i
<= i_high
; i
++)
2346 = gen_rtx_LABEL_REF (Pmode
, label_rtx (n
->code_label
));
2349 /* Fill in the gaps with the default. We may have gaps at
2350 the beginning if we tried to avoid the minval subtraction,
2351 so substitute some label even if the default label was
2352 deemed unreachable. */
2354 default_label
= fallback_label
;
2355 for (i
= 0; i
< ncases
; i
++)
2356 if (labelvec
[i
] == 0)
2357 labelvec
[i
] = gen_rtx_LABEL_REF (Pmode
, default_label
);
2359 /* Output the table. */
2360 emit_label (table_label
);
2362 if (CASE_VECTOR_PC_RELATIVE
|| flag_pic
)
2363 emit_jump_insn (gen_rtx_ADDR_DIFF_VEC (CASE_VECTOR_MODE
,
2364 gen_rtx_LABEL_REF (Pmode
, table_label
),
2365 gen_rtvec_v (ncases
, labelvec
),
2366 const0_rtx
, const0_rtx
));
2368 emit_jump_insn (gen_rtx_ADDR_VEC (CASE_VECTOR_MODE
,
2369 gen_rtvec_v (ncases
, labelvec
)));
2371 /* Record no drop-through after the table. */
2375 before_case
= NEXT_INSN (before_case
);
2376 end
= get_last_insn ();
2377 reorder_insns (before_case
, end
, start
);
2381 free_alloc_pool (case_node_pool
);
2384 /* Generate code to jump to LABEL if OP0 and OP1 are equal in mode MODE. */
2387 do_jump_if_equal (enum machine_mode mode
, rtx op0
, rtx op1
, rtx label
,
2390 do_compare_rtx_and_jump (op0
, op1
, EQ
, unsignedp
, mode
,
2391 NULL_RTX
, NULL_RTX
, label
, -1);
2394 /* Take an ordered list of case nodes
2395 and transform them into a near optimal binary tree,
2396 on the assumption that any target code selection value is as
2397 likely as any other.
2399 The transformation is performed by splitting the ordered
2400 list into two equal sections plus a pivot. The parts are
2401 then attached to the pivot as left and right branches. Each
2402 branch is then transformed recursively. */
2405 balance_case_nodes (case_node_ptr
*head
, case_node_ptr parent
)
2417 /* Count the number of entries on branch. Also count the ranges. */
2421 if (!tree_int_cst_equal (np
->low
, np
->high
))
2430 /* Split this list if it is long enough for that to help. */
2434 /* If there are just three nodes, split at the middle one. */
2436 npp
= &(*npp
)->right
;
2439 /* Find the place in the list that bisects the list's total cost,
2440 where ranges count as 2.
2441 Here I gets half the total cost. */
2442 i
= (i
+ ranges
+ 1) / 2;
2445 /* Skip nodes while their cost does not reach that amount. */
2446 if (!tree_int_cst_equal ((*npp
)->low
, (*npp
)->high
))
2451 npp
= &(*npp
)->right
;
2456 np
->parent
= parent
;
2459 /* Optimize each of the two split parts. */
2460 balance_case_nodes (&np
->left
, np
);
2461 balance_case_nodes (&np
->right
, np
);
2465 /* Else leave this branch as one level,
2466 but fill in `parent' fields. */
2468 np
->parent
= parent
;
2469 for (; np
->right
; np
= np
->right
)
2470 np
->right
->parent
= np
;
2475 /* Search the parent sections of the case node tree
2476 to see if a test for the lower bound of NODE would be redundant.
2477 INDEX_TYPE is the type of the index expression.
2479 The instructions to generate the case decision tree are
2480 output in the same order as nodes are processed so it is
2481 known that if a parent node checks the range of the current
2482 node minus one that the current node is bounded at its lower
2483 span. Thus the test would be redundant. */
2486 node_has_low_bound (case_node_ptr node
, tree index_type
)
2489 case_node_ptr pnode
;
2491 /* If the lower bound of this node is the lowest value in the index type,
2492 we need not test it. */
2494 if (tree_int_cst_equal (node
->low
, TYPE_MIN_VALUE (index_type
)))
2497 /* If this node has a left branch, the value at the left must be less
2498 than that at this node, so it cannot be bounded at the bottom and
2499 we need not bother testing any further. */
2504 low_minus_one
= fold_build2 (MINUS_EXPR
, TREE_TYPE (node
->low
),
2506 build_int_cst (TREE_TYPE (node
->low
), 1));
2508 /* If the subtraction above overflowed, we can't verify anything.
2509 Otherwise, look for a parent that tests our value - 1. */
2511 if (! tree_int_cst_lt (low_minus_one
, node
->low
))
2514 for (pnode
= node
->parent
; pnode
; pnode
= pnode
->parent
)
2515 if (tree_int_cst_equal (low_minus_one
, pnode
->high
))
2521 /* Search the parent sections of the case node tree
2522 to see if a test for the upper bound of NODE would be redundant.
2523 INDEX_TYPE is the type of the index expression.
2525 The instructions to generate the case decision tree are
2526 output in the same order as nodes are processed so it is
2527 known that if a parent node checks the range of the current
2528 node plus one that the current node is bounded at its upper
2529 span. Thus the test would be redundant. */
2532 node_has_high_bound (case_node_ptr node
, tree index_type
)
2535 case_node_ptr pnode
;
2537 /* If there is no upper bound, obviously no test is needed. */
2539 if (TYPE_MAX_VALUE (index_type
) == NULL
)
2542 /* If the upper bound of this node is the highest value in the type
2543 of the index expression, we need not test against it. */
2545 if (tree_int_cst_equal (node
->high
, TYPE_MAX_VALUE (index_type
)))
2548 /* If this node has a right branch, the value at the right must be greater
2549 than that at this node, so it cannot be bounded at the top and
2550 we need not bother testing any further. */
2555 high_plus_one
= fold_build2 (PLUS_EXPR
, TREE_TYPE (node
->high
),
2557 build_int_cst (TREE_TYPE (node
->high
), 1));
2559 /* If the addition above overflowed, we can't verify anything.
2560 Otherwise, look for a parent that tests our value + 1. */
2562 if (! tree_int_cst_lt (node
->high
, high_plus_one
))
2565 for (pnode
= node
->parent
; pnode
; pnode
= pnode
->parent
)
2566 if (tree_int_cst_equal (high_plus_one
, pnode
->low
))
2572 /* Search the parent sections of the
2573 case node tree to see if both tests for the upper and lower
2574 bounds of NODE would be redundant. */
2577 node_is_bounded (case_node_ptr node
, tree index_type
)
2579 return (node_has_low_bound (node
, index_type
)
2580 && node_has_high_bound (node
, index_type
));
2583 /* Emit step-by-step code to select a case for the value of INDEX.
2584 The thus generated decision tree follows the form of the
2585 case-node binary tree NODE, whose nodes represent test conditions.
2586 INDEX_TYPE is the type of the index of the switch.
2588 Care is taken to prune redundant tests from the decision tree
2589 by detecting any boundary conditions already checked by
2590 emitted rtx. (See node_has_high_bound, node_has_low_bound
2591 and node_is_bounded, above.)
2593 Where the test conditions can be shown to be redundant we emit
2594 an unconditional jump to the target code. As a further
2595 optimization, the subordinates of a tree node are examined to
2596 check for bounded nodes. In this case conditional and/or
2597 unconditional jumps as a result of the boundary check for the
2598 current node are arranged to target the subordinates associated
2599 code for out of bound conditions on the current node.
2601 We can assume that when control reaches the code generated here,
2602 the index value has already been compared with the parents
2603 of this node, and determined to be on the same side of each parent
2604 as this node is. Thus, if this node tests for the value 51,
2605 and a parent tested for 52, we don't need to consider
2606 the possibility of a value greater than 51. If another parent
2607 tests for the value 50, then this node need not test anything. */
2610 emit_case_nodes (rtx index
, case_node_ptr node
, rtx default_label
,
2613 /* If INDEX has an unsigned type, we must make unsigned branches. */
2614 int unsignedp
= TYPE_UNSIGNED (index_type
);
2615 enum machine_mode mode
= GET_MODE (index
);
2616 enum machine_mode imode
= TYPE_MODE (index_type
);
2618 /* Handle indices detected as constant during RTL expansion. */
2619 if (mode
== VOIDmode
)
2622 /* See if our parents have already tested everything for us.
2623 If they have, emit an unconditional jump for this node. */
2624 if (node_is_bounded (node
, index_type
))
2625 emit_jump (label_rtx (node
->code_label
));
2627 else if (tree_int_cst_equal (node
->low
, node
->high
))
2629 /* Node is single valued. First see if the index expression matches
2630 this node and then check our children, if any. */
2632 do_jump_if_equal (mode
, index
,
2633 convert_modes (mode
, imode
,
2634 expand_normal (node
->low
),
2636 label_rtx (node
->code_label
), unsignedp
);
2638 if (node
->right
!= 0 && node
->left
!= 0)
2640 /* This node has children on both sides.
2641 Dispatch to one side or the other
2642 by comparing the index value with this node's value.
2643 If one subtree is bounded, check that one first,
2644 so we can avoid real branches in the tree. */
2646 if (node_is_bounded (node
->right
, index_type
))
2648 emit_cmp_and_jump_insns (index
,
2651 expand_normal (node
->high
),
2653 GT
, NULL_RTX
, mode
, unsignedp
,
2654 label_rtx (node
->right
->code_label
));
2655 emit_case_nodes (index
, node
->left
, default_label
, index_type
);
2658 else if (node_is_bounded (node
->left
, index_type
))
2660 emit_cmp_and_jump_insns (index
,
2663 expand_normal (node
->high
),
2665 LT
, NULL_RTX
, mode
, unsignedp
,
2666 label_rtx (node
->left
->code_label
));
2667 emit_case_nodes (index
, node
->right
, default_label
, index_type
);
2670 /* If both children are single-valued cases with no
2671 children, finish up all the work. This way, we can save
2672 one ordered comparison. */
2673 else if (tree_int_cst_equal (node
->right
->low
, node
->right
->high
)
2674 && node
->right
->left
== 0
2675 && node
->right
->right
== 0
2676 && tree_int_cst_equal (node
->left
->low
, node
->left
->high
)
2677 && node
->left
->left
== 0
2678 && node
->left
->right
== 0)
2680 /* Neither node is bounded. First distinguish the two sides;
2681 then emit the code for one side at a time. */
2683 /* See if the value matches what the right hand side
2685 do_jump_if_equal (mode
, index
,
2686 convert_modes (mode
, imode
,
2687 expand_normal (node
->right
->low
),
2689 label_rtx (node
->right
->code_label
),
2692 /* See if the value matches what the left hand side
2694 do_jump_if_equal (mode
, index
,
2695 convert_modes (mode
, imode
,
2696 expand_normal (node
->left
->low
),
2698 label_rtx (node
->left
->code_label
),
2704 /* Neither node is bounded. First distinguish the two sides;
2705 then emit the code for one side at a time. */
2708 = build_decl (CURR_INSN_LOCATION
,
2709 LABEL_DECL
, NULL_TREE
, NULL_TREE
);
2711 /* See if the value is on the right. */
2712 emit_cmp_and_jump_insns (index
,
2715 expand_normal (node
->high
),
2717 GT
, NULL_RTX
, mode
, unsignedp
,
2718 label_rtx (test_label
));
2720 /* Value must be on the left.
2721 Handle the left-hand subtree. */
2722 emit_case_nodes (index
, node
->left
, default_label
, index_type
);
2723 /* If left-hand subtree does nothing,
2726 emit_jump (default_label
);
2728 /* Code branches here for the right-hand subtree. */
2729 expand_label (test_label
);
2730 emit_case_nodes (index
, node
->right
, default_label
, index_type
);
2734 else if (node
->right
!= 0 && node
->left
== 0)
2736 /* Here we have a right child but no left so we issue a conditional
2737 branch to default and process the right child.
2739 Omit the conditional branch to default if the right child
2740 does not have any children and is single valued; it would
2741 cost too much space to save so little time. */
2743 if (node
->right
->right
|| node
->right
->left
2744 || !tree_int_cst_equal (node
->right
->low
, node
->right
->high
))
2746 if (!node_has_low_bound (node
, index_type
))
2748 emit_cmp_and_jump_insns (index
,
2751 expand_normal (node
->high
),
2753 LT
, NULL_RTX
, mode
, unsignedp
,
2757 emit_case_nodes (index
, node
->right
, default_label
, index_type
);
2760 /* We cannot process node->right normally
2761 since we haven't ruled out the numbers less than
2762 this node's value. So handle node->right explicitly. */
2763 do_jump_if_equal (mode
, index
,
2766 expand_normal (node
->right
->low
),
2768 label_rtx (node
->right
->code_label
), unsignedp
);
2771 else if (node
->right
== 0 && node
->left
!= 0)
2773 /* Just one subtree, on the left. */
2774 if (node
->left
->left
|| node
->left
->right
2775 || !tree_int_cst_equal (node
->left
->low
, node
->left
->high
))
2777 if (!node_has_high_bound (node
, index_type
))
2779 emit_cmp_and_jump_insns (index
,
2782 expand_normal (node
->high
),
2784 GT
, NULL_RTX
, mode
, unsignedp
,
2788 emit_case_nodes (index
, node
->left
, default_label
, index_type
);
2791 /* We cannot process node->left normally
2792 since we haven't ruled out the numbers less than
2793 this node's value. So handle node->left explicitly. */
2794 do_jump_if_equal (mode
, index
,
2797 expand_normal (node
->left
->low
),
2799 label_rtx (node
->left
->code_label
), unsignedp
);
2804 /* Node is a range. These cases are very similar to those for a single
2805 value, except that we do not start by testing whether this node
2806 is the one to branch to. */
2808 if (node
->right
!= 0 && node
->left
!= 0)
2810 /* Node has subtrees on both sides.
2811 If the right-hand subtree is bounded,
2812 test for it first, since we can go straight there.
2813 Otherwise, we need to make a branch in the control structure,
2814 then handle the two subtrees. */
2815 tree test_label
= 0;
2817 if (node_is_bounded (node
->right
, index_type
))
2818 /* Right hand node is fully bounded so we can eliminate any
2819 testing and branch directly to the target code. */
2820 emit_cmp_and_jump_insns (index
,
2823 expand_normal (node
->high
),
2825 GT
, NULL_RTX
, mode
, unsignedp
,
2826 label_rtx (node
->right
->code_label
));
2829 /* Right hand node requires testing.
2830 Branch to a label where we will handle it later. */
2832 test_label
= build_decl (CURR_INSN_LOCATION
,
2833 LABEL_DECL
, NULL_TREE
, NULL_TREE
);
2834 emit_cmp_and_jump_insns (index
,
2837 expand_normal (node
->high
),
2839 GT
, NULL_RTX
, mode
, unsignedp
,
2840 label_rtx (test_label
));
2843 /* Value belongs to this node or to the left-hand subtree. */
2845 emit_cmp_and_jump_insns (index
,
2848 expand_normal (node
->low
),
2850 GE
, NULL_RTX
, mode
, unsignedp
,
2851 label_rtx (node
->code_label
));
2853 /* Handle the left-hand subtree. */
2854 emit_case_nodes (index
, node
->left
, default_label
, index_type
);
2856 /* If right node had to be handled later, do that now. */
2860 /* If the left-hand subtree fell through,
2861 don't let it fall into the right-hand subtree. */
2863 emit_jump (default_label
);
2865 expand_label (test_label
);
2866 emit_case_nodes (index
, node
->right
, default_label
, index_type
);
2870 else if (node
->right
!= 0 && node
->left
== 0)
2872 /* Deal with values to the left of this node,
2873 if they are possible. */
2874 if (!node_has_low_bound (node
, index_type
))
2876 emit_cmp_and_jump_insns (index
,
2879 expand_normal (node
->low
),
2881 LT
, NULL_RTX
, mode
, unsignedp
,
2885 /* Value belongs to this node or to the right-hand subtree. */
2887 emit_cmp_and_jump_insns (index
,
2890 expand_normal (node
->high
),
2892 LE
, NULL_RTX
, mode
, unsignedp
,
2893 label_rtx (node
->code_label
));
2895 emit_case_nodes (index
, node
->right
, default_label
, index_type
);
2898 else if (node
->right
== 0 && node
->left
!= 0)
2900 /* Deal with values to the right of this node,
2901 if they are possible. */
2902 if (!node_has_high_bound (node
, index_type
))
2904 emit_cmp_and_jump_insns (index
,
2907 expand_normal (node
->high
),
2909 GT
, NULL_RTX
, mode
, unsignedp
,
2913 /* Value belongs to this node or to the left-hand subtree. */
2915 emit_cmp_and_jump_insns (index
,
2918 expand_normal (node
->low
),
2920 GE
, NULL_RTX
, mode
, unsignedp
,
2921 label_rtx (node
->code_label
));
2923 emit_case_nodes (index
, node
->left
, default_label
, index_type
);
2928 /* Node has no children so we check low and high bounds to remove
2929 redundant tests. Only one of the bounds can exist,
2930 since otherwise this node is bounded--a case tested already. */
2931 int high_bound
= node_has_high_bound (node
, index_type
);
2932 int low_bound
= node_has_low_bound (node
, index_type
);
2934 if (!high_bound
&& low_bound
)
2936 emit_cmp_and_jump_insns (index
,
2939 expand_normal (node
->high
),
2941 GT
, NULL_RTX
, mode
, unsignedp
,
2945 else if (!low_bound
&& high_bound
)
2947 emit_cmp_and_jump_insns (index
,
2950 expand_normal (node
->low
),
2952 LT
, NULL_RTX
, mode
, unsignedp
,
2955 else if (!low_bound
&& !high_bound
)
2957 /* Widen LOW and HIGH to the same width as INDEX. */
2958 tree type
= lang_hooks
.types
.type_for_mode (mode
, unsignedp
);
2959 tree low
= build1 (CONVERT_EXPR
, type
, node
->low
);
2960 tree high
= build1 (CONVERT_EXPR
, type
, node
->high
);
2961 rtx low_rtx
, new_index
, new_bound
;
2963 /* Instead of doing two branches, emit one unsigned branch for
2964 (index-low) > (high-low). */
2965 low_rtx
= expand_expr (low
, NULL_RTX
, mode
, EXPAND_NORMAL
);
2966 new_index
= expand_simple_binop (mode
, MINUS
, index
, low_rtx
,
2967 NULL_RTX
, unsignedp
,
2969 new_bound
= expand_expr (fold_build2 (MINUS_EXPR
, type
,
2971 NULL_RTX
, mode
, EXPAND_NORMAL
);
2973 emit_cmp_and_jump_insns (new_index
, new_bound
, GT
, NULL_RTX
,
2974 mode
, 1, default_label
);
2977 emit_jump (label_rtx (node
->code_label
));