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, 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. */
916 generating_concat_p
= old_generating_concat_p
;
917 ASM_OPERANDS_INPUT (body
, i
) = op
;
919 ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body
, i
)
920 = gen_rtx_ASM_INPUT (TYPE_MODE (type
),
921 ggc_strdup (constraints
[i
+ noutputs
]));
923 if (tree_conflicts_with_clobbers_p (val
, &clobbered_regs
))
924 clobber_conflict_found
= 1;
927 /* Protect all the operands from the queue now that they have all been
930 generating_concat_p
= 0;
932 /* For in-out operands, copy output rtx to input rtx. */
933 for (i
= 0; i
< ninout
; i
++)
935 int j
= inout_opnum
[i
];
938 ASM_OPERANDS_INPUT (body
, ninputs
- ninout
+ i
)
941 sprintf (buffer
, "%d", j
);
942 ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body
, ninputs
- ninout
+ i
)
943 = gen_rtx_ASM_INPUT (inout_mode
[i
], ggc_strdup (buffer
));
946 /* Copy labels to the vector. */
947 for (i
= 0, tail
= labels
; i
< nlabels
; ++i
, tail
= TREE_CHAIN (tail
))
948 ASM_OPERANDS_LABEL (body
, i
)
949 = gen_rtx_LABEL_REF (Pmode
, label_rtx (TREE_VALUE (tail
)));
951 generating_concat_p
= old_generating_concat_p
;
953 /* Now, for each output, construct an rtx
954 (set OUTPUT (asm_operands INSN OUTPUTCONSTRAINT OUTPUTNUMBER
955 ARGVEC CONSTRAINTS OPNAMES))
956 If there is more than one, put them inside a PARALLEL. */
958 if (nlabels
> 0 && nclobbers
== 0)
960 gcc_assert (noutputs
== 0);
961 emit_jump_insn (body
);
963 else if (noutputs
== 0 && nclobbers
== 0)
965 /* No output operands: put in a raw ASM_OPERANDS rtx. */
968 else if (noutputs
== 1 && nclobbers
== 0)
970 ASM_OPERANDS_OUTPUT_CONSTRAINT (body
) = ggc_strdup (constraints
[0]);
971 emit_insn (gen_rtx_SET (VOIDmode
, output_rtx
[0], body
));
981 body
= gen_rtx_PARALLEL (VOIDmode
, rtvec_alloc (num
+ nclobbers
));
983 /* For each output operand, store a SET. */
984 for (i
= 0, tail
= outputs
; tail
; tail
= TREE_CHAIN (tail
), i
++)
987 = gen_rtx_SET (VOIDmode
,
990 (GET_MODE (output_rtx
[i
]),
991 ggc_strdup (TREE_STRING_POINTER (string
)),
992 ggc_strdup (constraints
[i
]),
993 i
, argvec
, constraintvec
, labelvec
, locus
));
995 MEM_VOLATILE_P (SET_SRC (XVECEXP (body
, 0, i
))) = vol
;
998 /* If there are no outputs (but there are some clobbers)
999 store the bare ASM_OPERANDS into the PARALLEL. */
1002 XVECEXP (body
, 0, i
++) = obody
;
1004 /* Store (clobber REG) for each clobbered register specified. */
1006 for (tail
= clobbers
; tail
; tail
= TREE_CHAIN (tail
))
1008 const char *regname
= TREE_STRING_POINTER (TREE_VALUE (tail
));
1010 int j
= decode_reg_name_and_count (regname
, &nregs
);
1015 if (j
== -3) /* `cc', which is not a register */
1018 if (j
== -4) /* `memory', don't cache memory across asm */
1020 XVECEXP (body
, 0, i
++)
1021 = gen_rtx_CLOBBER (VOIDmode
,
1024 gen_rtx_SCRATCH (VOIDmode
)));
1028 /* Ignore unknown register, error already signaled. */
1032 for (reg
= j
; reg
< j
+ nregs
; reg
++)
1034 /* Use QImode since that's guaranteed to clobber just
1036 clobbered_reg
= gen_rtx_REG (QImode
, reg
);
1038 /* Do sanity check for overlap between clobbers and
1039 respectively input and outputs that hasn't been
1040 handled. Such overlap should have been detected and
1042 if (!clobber_conflict_found
)
1046 /* We test the old body (obody) contents to avoid
1047 tripping over the under-construction body. */
1048 for (opno
= 0; opno
< noutputs
; opno
++)
1049 if (reg_overlap_mentioned_p (clobbered_reg
,
1052 ("asm clobber conflict with output operand");
1054 for (opno
= 0; opno
< ninputs
- ninout
; opno
++)
1055 if (reg_overlap_mentioned_p (clobbered_reg
,
1056 ASM_OPERANDS_INPUT (obody
,
1059 ("asm clobber conflict with input operand");
1062 XVECEXP (body
, 0, i
++)
1063 = gen_rtx_CLOBBER (VOIDmode
, clobbered_reg
);
1068 emit_jump_insn (body
);
1073 /* For any outputs that needed reloading into registers, spill them
1074 back to where they belong. */
1075 for (i
= 0; i
< noutputs
; ++i
)
1076 if (real_output_rtx
[i
])
1077 emit_move_insn (real_output_rtx
[i
], output_rtx
[i
]);
1079 crtl
->has_asm_statement
= 1;
1084 expand_asm_stmt (gimple stmt
)
1087 tree outputs
, tail
, t
;
1091 tree str
, out
, in
, cl
, labels
;
1092 location_t locus
= gimple_location (stmt
);
1094 /* Meh... convert the gimple asm operands into real tree lists.
1095 Eventually we should make all routines work on the vectors instead
1096 of relying on TREE_CHAIN. */
1098 n
= gimple_asm_noutputs (stmt
);
1101 t
= out
= gimple_asm_output_op (stmt
, 0);
1102 for (i
= 1; i
< n
; i
++)
1103 t
= TREE_CHAIN (t
) = gimple_asm_output_op (stmt
, i
);
1107 n
= gimple_asm_ninputs (stmt
);
1110 t
= in
= gimple_asm_input_op (stmt
, 0);
1111 for (i
= 1; i
< n
; i
++)
1112 t
= TREE_CHAIN (t
) = gimple_asm_input_op (stmt
, i
);
1116 n
= gimple_asm_nclobbers (stmt
);
1119 t
= cl
= gimple_asm_clobber_op (stmt
, 0);
1120 for (i
= 1; i
< n
; i
++)
1121 t
= TREE_CHAIN (t
) = gimple_asm_clobber_op (stmt
, i
);
1125 n
= gimple_asm_nlabels (stmt
);
1128 t
= labels
= gimple_asm_label_op (stmt
, 0);
1129 for (i
= 1; i
< n
; i
++)
1130 t
= TREE_CHAIN (t
) = gimple_asm_label_op (stmt
, i
);
1133 s
= gimple_asm_string (stmt
);
1134 str
= build_string (strlen (s
), s
);
1136 if (gimple_asm_input_p (stmt
))
1138 expand_asm_loc (str
, gimple_asm_volatile_p (stmt
), locus
);
1143 noutputs
= gimple_asm_noutputs (stmt
);
1144 /* o[I] is the place that output number I should be written. */
1145 o
= (tree
*) alloca (noutputs
* sizeof (tree
));
1147 /* Record the contents of OUTPUTS before it is modified. */
1148 for (i
= 0, tail
= outputs
; tail
; tail
= TREE_CHAIN (tail
), i
++)
1149 o
[i
] = TREE_VALUE (tail
);
1151 /* Generate the ASM_OPERANDS insn; store into the TREE_VALUEs of
1152 OUTPUTS some trees for where the values were actually stored. */
1153 expand_asm_operands (str
, outputs
, in
, cl
, labels
,
1154 gimple_asm_volatile_p (stmt
), locus
);
1156 /* Copy all the intermediate outputs into the specified outputs. */
1157 for (i
= 0, tail
= outputs
; tail
; tail
= TREE_CHAIN (tail
), i
++)
1159 if (o
[i
] != TREE_VALUE (tail
))
1161 expand_assignment (o
[i
], TREE_VALUE (tail
), false);
1164 /* Restore the original value so that it's correct the next
1165 time we expand this function. */
1166 TREE_VALUE (tail
) = o
[i
];
1171 /* A subroutine of expand_asm_operands. Check that all operands have
1172 the same number of alternatives. Return true if so. */
1175 check_operand_nalternatives (tree outputs
, tree inputs
)
1177 if (outputs
|| inputs
)
1179 tree tmp
= TREE_PURPOSE (outputs
? outputs
: inputs
);
1181 = n_occurrences (',', TREE_STRING_POINTER (TREE_VALUE (tmp
)));
1184 if (nalternatives
+ 1 > MAX_RECOG_ALTERNATIVES
)
1186 error ("too many alternatives in %<asm%>");
1193 const char *constraint
1194 = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tmp
)));
1196 if (n_occurrences (',', constraint
) != nalternatives
)
1198 error ("operand constraints for %<asm%> differ "
1199 "in number of alternatives");
1203 if (TREE_CHAIN (tmp
))
1204 tmp
= TREE_CHAIN (tmp
);
1206 tmp
= next
, next
= 0;
1213 /* A subroutine of expand_asm_operands. Check that all operand names
1214 are unique. Return true if so. We rely on the fact that these names
1215 are identifiers, and so have been canonicalized by get_identifier,
1216 so all we need are pointer comparisons. */
1219 check_unique_operand_names (tree outputs
, tree inputs
, tree labels
)
1221 tree i
, j
, i_name
= NULL_TREE
;
1223 for (i
= outputs
; i
; i
= TREE_CHAIN (i
))
1225 i_name
= TREE_PURPOSE (TREE_PURPOSE (i
));
1229 for (j
= TREE_CHAIN (i
); j
; j
= TREE_CHAIN (j
))
1230 if (simple_cst_equal (i_name
, TREE_PURPOSE (TREE_PURPOSE (j
))))
1234 for (i
= inputs
; i
; i
= TREE_CHAIN (i
))
1236 i_name
= TREE_PURPOSE (TREE_PURPOSE (i
));
1240 for (j
= TREE_CHAIN (i
); j
; j
= TREE_CHAIN (j
))
1241 if (simple_cst_equal (i_name
, TREE_PURPOSE (TREE_PURPOSE (j
))))
1243 for (j
= outputs
; j
; j
= TREE_CHAIN (j
))
1244 if (simple_cst_equal (i_name
, TREE_PURPOSE (TREE_PURPOSE (j
))))
1248 for (i
= labels
; i
; i
= TREE_CHAIN (i
))
1250 i_name
= TREE_PURPOSE (i
);
1254 for (j
= TREE_CHAIN (i
); j
; j
= TREE_CHAIN (j
))
1255 if (simple_cst_equal (i_name
, TREE_PURPOSE (j
)))
1257 for (j
= inputs
; j
; j
= TREE_CHAIN (j
))
1258 if (simple_cst_equal (i_name
, TREE_PURPOSE (TREE_PURPOSE (j
))))
1265 error ("duplicate asm operand name %qs", TREE_STRING_POINTER (i_name
));
1269 /* A subroutine of expand_asm_operands. Resolve the names of the operands
1270 in *POUTPUTS and *PINPUTS to numbers, and replace the name expansions in
1271 STRING and in the constraints to those numbers. */
1274 resolve_asm_operand_names (tree string
, tree outputs
, tree inputs
, tree labels
)
1281 check_unique_operand_names (outputs
, inputs
, labels
);
1283 /* Substitute [<name>] in input constraint strings. There should be no
1284 named operands in output constraints. */
1285 for (t
= inputs
; t
; t
= TREE_CHAIN (t
))
1287 c
= TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t
)));
1288 if (strchr (c
, '[') != NULL
)
1290 p
= buffer
= xstrdup (c
);
1291 while ((p
= strchr (p
, '[')) != NULL
)
1292 p
= resolve_operand_name_1 (p
, outputs
, inputs
, NULL
);
1293 TREE_VALUE (TREE_PURPOSE (t
))
1294 = build_string (strlen (buffer
), buffer
);
1299 /* Now check for any needed substitutions in the template. */
1300 c
= TREE_STRING_POINTER (string
);
1301 while ((c
= strchr (c
, '%')) != NULL
)
1305 else if (ISALPHA (c
[1]) && c
[2] == '[')
1309 c
+= 1 + (c
[1] == '%');
1316 /* OK, we need to make a copy so we can perform the substitutions.
1317 Assume that we will not need extra space--we get to remove '['
1318 and ']', which means we cannot have a problem until we have more
1319 than 999 operands. */
1320 buffer
= xstrdup (TREE_STRING_POINTER (string
));
1321 p
= buffer
+ (c
- TREE_STRING_POINTER (string
));
1323 while ((p
= strchr (p
, '%')) != NULL
)
1327 else if (ISALPHA (p
[1]) && p
[2] == '[')
1331 p
+= 1 + (p
[1] == '%');
1335 p
= resolve_operand_name_1 (p
, outputs
, inputs
, labels
);
1338 string
= build_string (strlen (buffer
), buffer
);
1345 /* A subroutine of resolve_operand_names. P points to the '[' for a
1346 potential named operand of the form [<name>]. In place, replace
1347 the name and brackets with a number. Return a pointer to the
1348 balance of the string after substitution. */
1351 resolve_operand_name_1 (char *p
, tree outputs
, tree inputs
, tree labels
)
1357 /* Collect the operand name. */
1358 q
= strchr (++p
, ']');
1361 error ("missing close brace for named operand");
1362 return strchr (p
, '\0');
1366 /* Resolve the name to a number. */
1367 for (op
= 0, t
= outputs
; t
; t
= TREE_CHAIN (t
), op
++)
1369 tree name
= TREE_PURPOSE (TREE_PURPOSE (t
));
1370 if (name
&& strcmp (TREE_STRING_POINTER (name
), p
) == 0)
1373 for (t
= inputs
; t
; t
= TREE_CHAIN (t
), op
++)
1375 tree name
= TREE_PURPOSE (TREE_PURPOSE (t
));
1376 if (name
&& strcmp (TREE_STRING_POINTER (name
), p
) == 0)
1379 for (t
= labels
; t
; t
= TREE_CHAIN (t
), op
++)
1381 tree name
= TREE_PURPOSE (t
);
1382 if (name
&& strcmp (TREE_STRING_POINTER (name
), p
) == 0)
1386 error ("undefined named operand %qs", identifier_to_locale (p
));
1390 /* Replace the name with the number. Unfortunately, not all libraries
1391 get the return value of sprintf correct, so search for the end of the
1392 generated string by hand. */
1393 sprintf (--p
, "%d", op
);
1394 p
= strchr (p
, '\0');
1396 /* Verify the no extra buffer space assumption. */
1397 gcc_assert (p
<= q
);
1399 /* Shift the rest of the buffer down to fill the gap. */
1400 memmove (p
, q
+ 1, strlen (q
+ 1) + 1);
1405 /* Generate RTL to evaluate the expression EXP. */
1408 expand_expr_stmt (tree exp
)
1413 value
= expand_expr (exp
, const0_rtx
, VOIDmode
, EXPAND_NORMAL
);
1414 type
= TREE_TYPE (exp
);
1416 /* If all we do is reference a volatile value in memory,
1417 copy it to a register to be sure it is actually touched. */
1418 if (value
&& MEM_P (value
) && TREE_THIS_VOLATILE (exp
))
1420 if (TYPE_MODE (type
) == VOIDmode
)
1422 else if (TYPE_MODE (type
) != BLKmode
)
1423 copy_to_reg (value
);
1426 rtx lab
= gen_label_rtx ();
1428 /* Compare the value with itself to reference it. */
1429 emit_cmp_and_jump_insns (value
, value
, EQ
,
1430 expand_normal (TYPE_SIZE (type
)),
1436 /* Free any temporaries used to evaluate this expression. */
1441 /* Generate RTL to return from the current function, with no value.
1442 (That is, we do not do anything about returning any value.) */
1445 expand_null_return (void)
1447 /* If this function was declared to return a value, but we
1448 didn't, clobber the return registers so that they are not
1449 propagated live to the rest of the function. */
1450 clobber_return_register ();
1452 expand_null_return_1 ();
1455 /* Generate RTL to return directly from the current function.
1456 (That is, we bypass any return value.) */
1459 expand_naked_return (void)
1463 clear_pending_stack_adjust ();
1464 do_pending_stack_adjust ();
1466 end_label
= naked_return_label
;
1468 end_label
= naked_return_label
= gen_label_rtx ();
1470 emit_jump (end_label
);
1473 /* Generate RTL to return from the current function, with value VAL. */
1476 expand_value_return (rtx val
)
1478 /* Copy the value to the return location unless it's already there. */
1480 tree decl
= DECL_RESULT (current_function_decl
);
1481 rtx return_reg
= DECL_RTL (decl
);
1482 if (return_reg
!= val
)
1484 tree funtype
= TREE_TYPE (current_function_decl
);
1485 tree type
= TREE_TYPE (decl
);
1486 int unsignedp
= TYPE_UNSIGNED (type
);
1487 enum machine_mode old_mode
= DECL_MODE (decl
);
1488 enum machine_mode mode
;
1489 if (DECL_BY_REFERENCE (decl
))
1490 mode
= promote_function_mode (type
, old_mode
, &unsignedp
, funtype
, 2);
1492 mode
= promote_function_mode (type
, old_mode
, &unsignedp
, funtype
, 1);
1494 if (mode
!= old_mode
)
1495 val
= convert_modes (mode
, old_mode
, val
, unsignedp
);
1497 if (GET_CODE (return_reg
) == PARALLEL
)
1498 emit_group_load (return_reg
, val
, type
, int_size_in_bytes (type
));
1500 emit_move_insn (return_reg
, val
);
1503 expand_null_return_1 ();
1506 /* Output a return with no value. */
1509 expand_null_return_1 (void)
1511 clear_pending_stack_adjust ();
1512 do_pending_stack_adjust ();
1513 emit_jump (return_label
);
1516 /* Generate RTL to evaluate the expression RETVAL and return it
1517 from the current function. */
1520 expand_return (tree retval
)
1526 /* If function wants no value, give it none. */
1527 if (TREE_CODE (TREE_TYPE (TREE_TYPE (current_function_decl
))) == VOID_TYPE
)
1529 expand_normal (retval
);
1530 expand_null_return ();
1534 if (retval
== error_mark_node
)
1536 /* Treat this like a return of no value from a function that
1538 expand_null_return ();
1541 else if ((TREE_CODE (retval
) == MODIFY_EXPR
1542 || TREE_CODE (retval
) == INIT_EXPR
)
1543 && TREE_CODE (TREE_OPERAND (retval
, 0)) == RESULT_DECL
)
1544 retval_rhs
= TREE_OPERAND (retval
, 1);
1546 retval_rhs
= retval
;
1548 result_rtl
= DECL_RTL (DECL_RESULT (current_function_decl
));
1550 /* If we are returning the RESULT_DECL, then the value has already
1551 been stored into it, so we don't have to do anything special. */
1552 if (TREE_CODE (retval_rhs
) == RESULT_DECL
)
1553 expand_value_return (result_rtl
);
1555 /* If the result is an aggregate that is being returned in one (or more)
1556 registers, load the registers here. */
1558 else if (retval_rhs
!= 0
1559 && TYPE_MODE (TREE_TYPE (retval_rhs
)) == BLKmode
1560 && REG_P (result_rtl
))
1562 val
= copy_blkmode_to_reg (GET_MODE (result_rtl
), retval_rhs
);
1565 /* Use the mode of the result value on the return register. */
1566 PUT_MODE (result_rtl
, GET_MODE (val
));
1567 expand_value_return (val
);
1570 expand_null_return ();
1572 else if (retval_rhs
!= 0
1573 && !VOID_TYPE_P (TREE_TYPE (retval_rhs
))
1574 && (REG_P (result_rtl
)
1575 || (GET_CODE (result_rtl
) == PARALLEL
)))
1577 /* Calculate the return value into a temporary (usually a pseudo
1579 tree ot
= TREE_TYPE (DECL_RESULT (current_function_decl
));
1580 tree nt
= build_qualified_type (ot
, TYPE_QUALS (ot
) | TYPE_QUAL_CONST
);
1582 val
= assign_temp (nt
, 0, 1);
1583 val
= expand_expr (retval_rhs
, val
, GET_MODE (val
), EXPAND_NORMAL
);
1584 val
= force_not_mem (val
);
1585 /* Return the calculated value. */
1586 expand_value_return (val
);
1590 /* No hard reg used; calculate value into hard return reg. */
1591 expand_expr (retval
, const0_rtx
, VOIDmode
, EXPAND_NORMAL
);
1592 expand_value_return (result_rtl
);
1596 /* Emit code to restore vital registers at the beginning of a nonlocal goto
1599 expand_nl_goto_receiver (void)
1603 /* Clobber the FP when we get here, so we have to make sure it's
1604 marked as used by this function. */
1605 emit_use (hard_frame_pointer_rtx
);
1607 /* Mark the static chain as clobbered here so life information
1608 doesn't get messed up for it. */
1609 chain
= targetm
.calls
.static_chain (current_function_decl
, true);
1610 if (chain
&& REG_P (chain
))
1611 emit_clobber (chain
);
1613 #ifdef HAVE_nonlocal_goto
1614 if (! HAVE_nonlocal_goto
)
1616 /* First adjust our frame pointer to its actual value. It was
1617 previously set to the start of the virtual area corresponding to
1618 the stacked variables when we branched here and now needs to be
1619 adjusted to the actual hardware fp value.
1621 Assignments are to virtual registers are converted by
1622 instantiate_virtual_regs into the corresponding assignment
1623 to the underlying register (fp in this case) that makes
1624 the original assignment true.
1625 So the following insn will actually be
1626 decrementing fp by STARTING_FRAME_OFFSET. */
1627 emit_move_insn (virtual_stack_vars_rtx
, hard_frame_pointer_rtx
);
1629 #if !HARD_FRAME_POINTER_IS_ARG_POINTER
1630 if (fixed_regs
[ARG_POINTER_REGNUM
])
1632 #ifdef ELIMINABLE_REGS
1633 /* If the argument pointer can be eliminated in favor of the
1634 frame pointer, we don't need to restore it. We assume here
1635 that if such an elimination is present, it can always be used.
1636 This is the case on all known machines; if we don't make this
1637 assumption, we do unnecessary saving on many machines. */
1638 static const struct elims
{const int from
, to
;} elim_regs
[] = ELIMINABLE_REGS
;
1641 for (i
= 0; i
< ARRAY_SIZE (elim_regs
); i
++)
1642 if (elim_regs
[i
].from
== ARG_POINTER_REGNUM
1643 && elim_regs
[i
].to
== HARD_FRAME_POINTER_REGNUM
)
1646 if (i
== ARRAY_SIZE (elim_regs
))
1649 /* Now restore our arg pointer from the address at which it
1650 was saved in our stack frame. */
1651 emit_move_insn (crtl
->args
.internal_arg_pointer
,
1652 copy_to_reg (get_arg_pointer_save_area ()));
1657 #ifdef HAVE_nonlocal_goto_receiver
1658 if (HAVE_nonlocal_goto_receiver
)
1659 emit_insn (gen_nonlocal_goto_receiver ());
1662 /* We must not allow the code we just generated to be reordered by
1663 scheduling. Specifically, the update of the frame pointer must
1664 happen immediately, not later. */
1665 emit_insn (gen_blockage ());
1668 /* Emit code to save the current value of stack. */
1670 expand_stack_save (void)
1674 do_pending_stack_adjust ();
1675 emit_stack_save (SAVE_BLOCK
, &ret
);
1679 /* Emit code to restore the current value of stack. */
1681 expand_stack_restore (tree var
)
1683 rtx prev
, sa
= expand_normal (var
);
1685 sa
= convert_memory_address (Pmode
, sa
);
1687 prev
= get_last_insn ();
1688 emit_stack_restore (SAVE_BLOCK
, sa
);
1689 fixup_args_size_notes (prev
, get_last_insn (), 0);
1692 /* Do the insertion of a case label into case_list. The labels are
1693 fed to us in descending order from the sorted vector of case labels used
1694 in the tree part of the middle end. So the list we construct is
1695 sorted in ascending order. The bounds on the case range, LOW and HIGH,
1696 are converted to case's index type TYPE. Note that the original type
1697 of the case index in the source code is usually "lost" during
1698 gimplification due to type promotion, but the case labels retain the
1701 static struct case_node
*
1702 add_case_node (struct case_node
*head
, tree type
, tree low
, tree high
,
1703 tree label
, alloc_pool case_node_pool
)
1705 struct case_node
*r
;
1707 gcc_checking_assert (low
);
1708 gcc_checking_assert (! high
|| (TREE_TYPE (low
) == TREE_TYPE (high
)));
1710 /* Add this label to the chain. Make sure to drop overflow flags. */
1711 r
= (struct case_node
*) pool_alloc (case_node_pool
);
1712 r
->low
= build_int_cst_wide (type
, TREE_INT_CST_LOW (low
),
1713 TREE_INT_CST_HIGH (low
));
1714 r
->high
= build_int_cst_wide (type
, TREE_INT_CST_LOW (high
),
1715 TREE_INT_CST_HIGH (high
));
1716 r
->code_label
= label
;
1717 r
->parent
= r
->left
= NULL
;
1722 /* Maximum number of case bit tests. */
1723 #define MAX_CASE_BIT_TESTS 3
1725 /* A case_bit_test represents a set of case nodes that may be
1726 selected from using a bit-wise comparison. HI and LO hold
1727 the integer to be tested against, LABEL contains the label
1728 to jump to upon success and BITS counts the number of case
1729 nodes handled by this test, typically the number of bits
1732 struct case_bit_test
1740 /* Determine whether "1 << x" is relatively cheap in word_mode. */
1743 bool lshift_cheap_p (void)
1745 static bool init
[2] = {false, false};
1746 static bool cheap
[2] = {true, true};
1748 bool speed_p
= optimize_insn_for_speed_p ();
1752 rtx reg
= gen_rtx_REG (word_mode
, 10000);
1753 int cost
= set_src_cost (gen_rtx_ASHIFT (word_mode
, const1_rtx
, reg
),
1755 cheap
[speed_p
] = cost
< COSTS_N_INSNS (3);
1756 init
[speed_p
] = true;
1759 return cheap
[speed_p
];
1762 /* Comparison function for qsort to order bit tests by decreasing
1763 number of case nodes, i.e. the node with the most cases gets
1767 case_bit_test_cmp (const void *p1
, const void *p2
)
1769 const struct case_bit_test
*const d1
= (const struct case_bit_test
*) p1
;
1770 const struct case_bit_test
*const d2
= (const struct case_bit_test
*) p2
;
1772 if (d2
->bits
!= d1
->bits
)
1773 return d2
->bits
- d1
->bits
;
1775 /* Stabilize the sort. */
1776 return CODE_LABEL_NUMBER (d2
->label
) - CODE_LABEL_NUMBER (d1
->label
);
1779 /* Expand a switch statement by a short sequence of bit-wise
1780 comparisons. "switch(x)" is effectively converted into
1781 "if ((1 << (x-MINVAL)) & CST)" where CST and MINVAL are
1784 INDEX_EXPR is the value being switched on, which is of
1785 type INDEX_TYPE. MINVAL is the lowest case value of in
1786 the case nodes, of INDEX_TYPE type, and RANGE is highest
1787 value minus MINVAL, also of type INDEX_TYPE. NODES is
1788 the set of case nodes, and DEFAULT_LABEL is the label to
1789 branch to should none of the cases match.
1791 There *MUST* be MAX_CASE_BIT_TESTS or less unique case
1795 emit_case_bit_tests (tree index_type
, tree index_expr
, tree minval
,
1796 tree range
, case_node_ptr nodes
, rtx default_label
)
1798 struct case_bit_test test
[MAX_CASE_BIT_TESTS
];
1799 enum machine_mode mode
;
1800 rtx expr
, index
, label
;
1801 unsigned int i
,j
,lo
,hi
;
1802 struct case_node
*n
;
1806 for (n
= nodes
; n
; n
= n
->right
)
1808 label
= label_rtx (n
->code_label
);
1809 for (i
= 0; i
< count
; i
++)
1810 if (label
== test
[i
].label
)
1815 gcc_assert (count
< MAX_CASE_BIT_TESTS
);
1818 test
[i
].label
= label
;
1825 lo
= tree_low_cst (fold_build2 (MINUS_EXPR
, index_type
,
1826 n
->low
, minval
), 1);
1827 hi
= tree_low_cst (fold_build2 (MINUS_EXPR
, index_type
,
1828 n
->high
, minval
), 1);
1829 for (j
= lo
; j
<= hi
; j
++)
1830 if (j
>= HOST_BITS_PER_WIDE_INT
)
1831 test
[i
].hi
|= (HOST_WIDE_INT
) 1 << (j
- HOST_BITS_PER_INT
);
1833 test
[i
].lo
|= (HOST_WIDE_INT
) 1 << j
;
1836 qsort (test
, count
, sizeof(*test
), case_bit_test_cmp
);
1838 index_expr
= fold_build2 (MINUS_EXPR
, index_type
,
1839 fold_convert (index_type
, index_expr
),
1840 fold_convert (index_type
, minval
));
1841 index
= expand_normal (index_expr
);
1842 do_pending_stack_adjust ();
1844 mode
= TYPE_MODE (index_type
);
1845 expr
= expand_normal (range
);
1847 emit_cmp_and_jump_insns (index
, expr
, GTU
, NULL_RTX
, mode
, 1,
1850 index
= convert_to_mode (word_mode
, index
, 0);
1851 index
= expand_binop (word_mode
, ashl_optab
, const1_rtx
,
1852 index
, NULL_RTX
, 1, OPTAB_WIDEN
);
1854 for (i
= 0; i
< count
; i
++)
1856 expr
= immed_double_const (test
[i
].lo
, test
[i
].hi
, word_mode
);
1857 expr
= expand_binop (word_mode
, and_optab
, index
, expr
,
1858 NULL_RTX
, 1, OPTAB_WIDEN
);
1859 emit_cmp_and_jump_insns (expr
, const0_rtx
, NE
, NULL_RTX
,
1860 word_mode
, 1, test
[i
].label
);
1864 emit_jump (default_label
);
1868 #define HAVE_casesi 0
1871 #ifndef HAVE_tablejump
1872 #define HAVE_tablejump 0
1875 /* Return true if a switch should be expanded as a bit test.
1876 INDEX_EXPR is the index expression, RANGE is the difference between
1877 highest and lowest case, UNIQ is number of unique case node targets
1878 not counting the default case and COUNT is the number of comparisons
1879 needed, not counting the default case. */
1881 expand_switch_using_bit_tests_p (tree index_expr
, tree range
,
1882 unsigned int uniq
, unsigned int count
)
1884 if (optab_handler (ashl_optab
, word_mode
) == CODE_FOR_nothing
)
1887 return (! TREE_CONSTANT (index_expr
)
1888 && compare_tree_int (range
, GET_MODE_BITSIZE (word_mode
)) < 0
1889 && compare_tree_int (range
, 0) > 0
1890 && lshift_cheap_p ()
1891 && ((uniq
== 1 && count
>= 3)
1892 || (uniq
== 2 && count
>= 5)
1893 || (uniq
== 3 && count
>= 6)));
1896 /* Return the smallest number of different values for which it is best to use a
1897 jump-table instead of a tree of conditional branches. */
1900 case_values_threshold (void)
1902 unsigned int threshold
= PARAM_VALUE (PARAM_CASE_VALUES_THRESHOLD
);
1905 threshold
= targetm
.case_values_threshold ();
1910 /* Terminate a case (Pascal/Ada) or switch (C) statement
1911 in which ORIG_INDEX is the expression to be tested.
1912 If ORIG_TYPE is not NULL, it is the original ORIG_INDEX
1913 type as given in the source before any compiler conversions.
1914 Generate the code to test it and jump to the right place. */
1917 expand_case (gimple stmt
)
1919 tree minval
= NULL_TREE
, maxval
= NULL_TREE
, range
= NULL_TREE
;
1920 rtx default_label
= 0;
1921 struct case_node
*n
;
1922 unsigned int count
, uniq
;
1928 rtx before_case
, end
, lab
;
1930 tree index_expr
= gimple_switch_index (stmt
);
1931 tree index_type
= TREE_TYPE (index_expr
);
1932 int unsignedp
= TYPE_UNSIGNED (index_type
);
1934 /* The insn after which the case dispatch should finally
1935 be emitted. Zero for a dummy. */
1938 /* A list of case labels; it is first built as a list and it may then
1939 be rearranged into a nearly balanced binary tree. */
1940 struct case_node
*case_list
= 0;
1942 /* Label to jump to if no case matches. */
1943 tree default_label_decl
= NULL_TREE
;
1945 alloc_pool case_node_pool
= create_alloc_pool ("struct case_node pool",
1946 sizeof (struct case_node
),
1949 do_pending_stack_adjust ();
1951 /* An ERROR_MARK occurs for various reasons including invalid data type. */
1952 if (index_type
!= error_mark_node
)
1955 bitmap label_bitmap
;
1958 /* cleanup_tree_cfg removes all SWITCH_EXPR with their index
1959 expressions being INTEGER_CST. */
1960 gcc_assert (TREE_CODE (index_expr
) != INTEGER_CST
);
1962 /* The default case, if ever taken, is the first element. */
1963 elt
= gimple_switch_label (stmt
, 0);
1964 if (!CASE_LOW (elt
) && !CASE_HIGH (elt
))
1966 default_label_decl
= CASE_LABEL (elt
);
1970 for (i
= gimple_switch_num_labels (stmt
) - 1; i
>= stopi
; --i
)
1973 elt
= gimple_switch_label (stmt
, i
);
1975 low
= CASE_LOW (elt
);
1977 high
= CASE_HIGH (elt
);
1979 /* The canonical from of a case label in GIMPLE is that a simple case
1980 has an empty CASE_HIGH. For the casesi and tablejump expanders,
1981 the back ends want simple cases to have high == low. */
1982 gcc_assert (! high
|| tree_int_cst_lt (low
, high
));
1986 case_list
= add_case_node (case_list
, index_type
, low
, high
,
1987 CASE_LABEL (elt
), case_node_pool
);
1991 before_case
= start
= get_last_insn ();
1992 if (default_label_decl
)
1993 default_label
= label_rtx (default_label_decl
);
1995 /* Get upper and lower bounds of case values. */
1999 label_bitmap
= BITMAP_ALLOC (NULL
);
2000 for (n
= case_list
; n
; n
= n
->right
)
2002 /* Count the elements and track the largest and smallest
2003 of them (treating them as signed even if they are not). */
2011 if (tree_int_cst_lt (n
->low
, minval
))
2013 if (tree_int_cst_lt (maxval
, n
->high
))
2016 /* A range counts double, since it requires two compares. */
2017 if (! tree_int_cst_equal (n
->low
, n
->high
))
2020 /* If we have not seen this label yet, then increase the
2021 number of unique case node targets seen. */
2022 lab
= label_rtx (n
->code_label
);
2023 if (bitmap_set_bit (label_bitmap
, CODE_LABEL_NUMBER (lab
)))
2027 BITMAP_FREE (label_bitmap
);
2029 /* cleanup_tree_cfg removes all SWITCH_EXPR with a single
2030 destination, such as one with a default case only.
2031 It also removes cases that are out of range for the switch
2032 type, so we should never get a zero here. */
2033 gcc_assert (count
> 0);
2035 /* Compute span of values. */
2036 range
= fold_build2 (MINUS_EXPR
, index_type
, maxval
, minval
);
2038 /* Try implementing this switch statement by a short sequence of
2039 bit-wise comparisons. However, we let the binary-tree case
2040 below handle constant index expressions. */
2041 if (expand_switch_using_bit_tests_p (index_expr
, range
, uniq
, count
))
2043 /* Optimize the case where all the case values fit in a
2044 word without having to subtract MINVAL. In this case,
2045 we can optimize away the subtraction. */
2046 if (compare_tree_int (minval
, 0) > 0
2047 && compare_tree_int (maxval
, GET_MODE_BITSIZE (word_mode
)) < 0)
2049 minval
= build_int_cst (index_type
, 0);
2052 emit_case_bit_tests (index_type
, index_expr
, minval
, range
,
2053 case_list
, default_label
);
2056 /* If range of values is much bigger than number of values,
2057 make a sequence of conditional branches instead of a dispatch.
2058 If the switch-index is a constant, do it this way
2059 because we can optimize it. */
2061 else if (count
< case_values_threshold ()
2062 || compare_tree_int (range
,
2063 (optimize_insn_for_size_p () ? 3 : 10) * count
) > 0
2064 /* RANGE may be signed, and really large ranges will show up
2065 as negative numbers. */
2066 || compare_tree_int (range
, 0) < 0
2067 || !flag_jump_tables
2068 || TREE_CONSTANT (index_expr
)
2069 /* If neither casesi or tablejump is available, we can
2070 only go this way. */
2071 || (!HAVE_casesi
&& !HAVE_tablejump
))
2073 index
= expand_normal (index_expr
);
2075 /* If the index is a short or char that we do not have
2076 an insn to handle comparisons directly, convert it to
2077 a full integer now, rather than letting each comparison
2078 generate the conversion. */
2080 if (GET_MODE_CLASS (GET_MODE (index
)) == MODE_INT
2081 && ! have_insn_for (COMPARE
, GET_MODE (index
)))
2083 enum machine_mode wider_mode
;
2084 for (wider_mode
= GET_MODE (index
); wider_mode
!= VOIDmode
;
2085 wider_mode
= GET_MODE_WIDER_MODE (wider_mode
))
2086 if (have_insn_for (COMPARE
, wider_mode
))
2088 index
= convert_to_mode (wider_mode
, index
, unsignedp
);
2093 do_pending_stack_adjust ();
2097 index
= copy_to_reg (index
);
2098 if (TREE_CODE (index_expr
) == SSA_NAME
)
2099 set_reg_attrs_for_decl_rtl (SSA_NAME_VAR (index_expr
), index
);
2102 /* We generate a binary decision tree to select the
2103 appropriate target code. This is done as follows:
2105 The list of cases is rearranged into a binary tree,
2106 nearly optimal assuming equal probability for each case.
2108 The tree is transformed into RTL, eliminating
2109 redundant test conditions at the same time.
2111 If program flow could reach the end of the
2112 decision tree an unconditional jump to the
2113 default code is emitted. */
2115 balance_case_nodes (&case_list
, NULL
);
2116 emit_case_nodes (index
, case_list
, default_label
, index_type
);
2118 emit_jump (default_label
);
2122 rtx fallback_label
= label_rtx (case_list
->code_label
);
2123 table_label
= gen_label_rtx ();
2124 if (! try_casesi (index_type
, index_expr
, minval
, range
,
2125 table_label
, default_label
, fallback_label
))
2129 /* Index jumptables from zero for suitable values of
2130 minval to avoid a subtraction. */
2131 if (optimize_insn_for_speed_p ()
2132 && compare_tree_int (minval
, 0) > 0
2133 && compare_tree_int (minval
, 3) < 0)
2135 minval
= build_int_cst (index_type
, 0);
2139 ok
= try_tablejump (index_type
, index_expr
, minval
, range
,
2140 table_label
, default_label
);
2144 /* Get table of labels to jump to, in order of case index. */
2146 ncases
= tree_low_cst (range
, 0) + 1;
2147 labelvec
= XALLOCAVEC (rtx
, ncases
);
2148 memset (labelvec
, 0, ncases
* sizeof (rtx
));
2150 for (n
= case_list
; n
; n
= n
->right
)
2152 /* Compute the low and high bounds relative to the minimum
2153 value since that should fit in a HOST_WIDE_INT while the
2154 actual values may not. */
2156 = tree_low_cst (fold_build2 (MINUS_EXPR
, index_type
,
2157 n
->low
, minval
), 1);
2158 HOST_WIDE_INT i_high
2159 = tree_low_cst (fold_build2 (MINUS_EXPR
, index_type
,
2160 n
->high
, minval
), 1);
2163 for (i
= i_low
; i
<= i_high
; i
++)
2165 = gen_rtx_LABEL_REF (Pmode
, label_rtx (n
->code_label
));
2168 /* Fill in the gaps with the default. We may have gaps at
2169 the beginning if we tried to avoid the minval subtraction,
2170 so substitute some label even if the default label was
2171 deemed unreachable. */
2173 default_label
= fallback_label
;
2174 for (i
= 0; i
< ncases
; i
++)
2175 if (labelvec
[i
] == 0)
2176 labelvec
[i
] = gen_rtx_LABEL_REF (Pmode
, default_label
);
2178 /* Output the table. */
2179 emit_label (table_label
);
2181 if (CASE_VECTOR_PC_RELATIVE
|| flag_pic
)
2182 emit_jump_insn (gen_rtx_ADDR_DIFF_VEC (CASE_VECTOR_MODE
,
2183 gen_rtx_LABEL_REF (Pmode
, table_label
),
2184 gen_rtvec_v (ncases
, labelvec
),
2185 const0_rtx
, const0_rtx
));
2187 emit_jump_insn (gen_rtx_ADDR_VEC (CASE_VECTOR_MODE
,
2188 gen_rtvec_v (ncases
, labelvec
)));
2190 /* Record no drop-through after the table. */
2194 before_case
= NEXT_INSN (before_case
);
2195 end
= get_last_insn ();
2196 reorder_insns (before_case
, end
, start
);
2200 free_alloc_pool (case_node_pool
);
2203 /* Generate code to jump to LABEL if OP0 and OP1 are equal in mode MODE. */
2206 do_jump_if_equal (enum machine_mode mode
, rtx op0
, rtx op1
, rtx label
,
2209 do_compare_rtx_and_jump (op0
, op1
, EQ
, unsignedp
, mode
,
2210 NULL_RTX
, NULL_RTX
, label
, -1);
2213 /* Take an ordered list of case nodes
2214 and transform them into a near optimal binary tree,
2215 on the assumption that any target code selection value is as
2216 likely as any other.
2218 The transformation is performed by splitting the ordered
2219 list into two equal sections plus a pivot. The parts are
2220 then attached to the pivot as left and right branches. Each
2221 branch is then transformed recursively. */
2224 balance_case_nodes (case_node_ptr
*head
, case_node_ptr parent
)
2236 /* Count the number of entries on branch. Also count the ranges. */
2240 if (!tree_int_cst_equal (np
->low
, np
->high
))
2249 /* Split this list if it is long enough for that to help. */
2253 /* If there are just three nodes, split at the middle one. */
2255 npp
= &(*npp
)->right
;
2258 /* Find the place in the list that bisects the list's total cost,
2259 where ranges count as 2.
2260 Here I gets half the total cost. */
2261 i
= (i
+ ranges
+ 1) / 2;
2264 /* Skip nodes while their cost does not reach that amount. */
2265 if (!tree_int_cst_equal ((*npp
)->low
, (*npp
)->high
))
2270 npp
= &(*npp
)->right
;
2275 np
->parent
= parent
;
2278 /* Optimize each of the two split parts. */
2279 balance_case_nodes (&np
->left
, np
);
2280 balance_case_nodes (&np
->right
, np
);
2284 /* Else leave this branch as one level,
2285 but fill in `parent' fields. */
2287 np
->parent
= parent
;
2288 for (; np
->right
; np
= np
->right
)
2289 np
->right
->parent
= np
;
2294 /* Search the parent sections of the case node tree
2295 to see if a test for the lower bound of NODE would be redundant.
2296 INDEX_TYPE is the type of the index expression.
2298 The instructions to generate the case decision tree are
2299 output in the same order as nodes are processed so it is
2300 known that if a parent node checks the range of the current
2301 node minus one that the current node is bounded at its lower
2302 span. Thus the test would be redundant. */
2305 node_has_low_bound (case_node_ptr node
, tree index_type
)
2308 case_node_ptr pnode
;
2310 /* If the lower bound of this node is the lowest value in the index type,
2311 we need not test it. */
2313 if (tree_int_cst_equal (node
->low
, TYPE_MIN_VALUE (index_type
)))
2316 /* If this node has a left branch, the value at the left must be less
2317 than that at this node, so it cannot be bounded at the bottom and
2318 we need not bother testing any further. */
2323 low_minus_one
= fold_build2 (MINUS_EXPR
, TREE_TYPE (node
->low
),
2325 build_int_cst (TREE_TYPE (node
->low
), 1));
2327 /* If the subtraction above overflowed, we can't verify anything.
2328 Otherwise, look for a parent that tests our value - 1. */
2330 if (! tree_int_cst_lt (low_minus_one
, node
->low
))
2333 for (pnode
= node
->parent
; pnode
; pnode
= pnode
->parent
)
2334 if (tree_int_cst_equal (low_minus_one
, pnode
->high
))
2340 /* Search the parent sections of the case node tree
2341 to see if a test for the upper bound of NODE would be redundant.
2342 INDEX_TYPE is the type of the index expression.
2344 The instructions to generate the case decision tree are
2345 output in the same order as nodes are processed so it is
2346 known that if a parent node checks the range of the current
2347 node plus one that the current node is bounded at its upper
2348 span. Thus the test would be redundant. */
2351 node_has_high_bound (case_node_ptr node
, tree index_type
)
2354 case_node_ptr pnode
;
2356 /* If there is no upper bound, obviously no test is needed. */
2358 if (TYPE_MAX_VALUE (index_type
) == NULL
)
2361 /* If the upper bound of this node is the highest value in the type
2362 of the index expression, we need not test against it. */
2364 if (tree_int_cst_equal (node
->high
, TYPE_MAX_VALUE (index_type
)))
2367 /* If this node has a right branch, the value at the right must be greater
2368 than that at this node, so it cannot be bounded at the top and
2369 we need not bother testing any further. */
2374 high_plus_one
= fold_build2 (PLUS_EXPR
, TREE_TYPE (node
->high
),
2376 build_int_cst (TREE_TYPE (node
->high
), 1));
2378 /* If the addition above overflowed, we can't verify anything.
2379 Otherwise, look for a parent that tests our value + 1. */
2381 if (! tree_int_cst_lt (node
->high
, high_plus_one
))
2384 for (pnode
= node
->parent
; pnode
; pnode
= pnode
->parent
)
2385 if (tree_int_cst_equal (high_plus_one
, pnode
->low
))
2391 /* Search the parent sections of the
2392 case node tree to see if both tests for the upper and lower
2393 bounds of NODE would be redundant. */
2396 node_is_bounded (case_node_ptr node
, tree index_type
)
2398 return (node_has_low_bound (node
, index_type
)
2399 && node_has_high_bound (node
, index_type
));
2402 /* Emit step-by-step code to select a case for the value of INDEX.
2403 The thus generated decision tree follows the form of the
2404 case-node binary tree NODE, whose nodes represent test conditions.
2405 INDEX_TYPE is the type of the index of the switch.
2407 Care is taken to prune redundant tests from the decision tree
2408 by detecting any boundary conditions already checked by
2409 emitted rtx. (See node_has_high_bound, node_has_low_bound
2410 and node_is_bounded, above.)
2412 Where the test conditions can be shown to be redundant we emit
2413 an unconditional jump to the target code. As a further
2414 optimization, the subordinates of a tree node are examined to
2415 check for bounded nodes. In this case conditional and/or
2416 unconditional jumps as a result of the boundary check for the
2417 current node are arranged to target the subordinates associated
2418 code for out of bound conditions on the current node.
2420 We can assume that when control reaches the code generated here,
2421 the index value has already been compared with the parents
2422 of this node, and determined to be on the same side of each parent
2423 as this node is. Thus, if this node tests for the value 51,
2424 and a parent tested for 52, we don't need to consider
2425 the possibility of a value greater than 51. If another parent
2426 tests for the value 50, then this node need not test anything. */
2429 emit_case_nodes (rtx index
, case_node_ptr node
, rtx default_label
,
2432 /* If INDEX has an unsigned type, we must make unsigned branches. */
2433 int unsignedp
= TYPE_UNSIGNED (index_type
);
2434 enum machine_mode mode
= GET_MODE (index
);
2435 enum machine_mode imode
= TYPE_MODE (index_type
);
2437 /* Handle indices detected as constant during RTL expansion. */
2438 if (mode
== VOIDmode
)
2441 /* See if our parents have already tested everything for us.
2442 If they have, emit an unconditional jump for this node. */
2443 if (node_is_bounded (node
, index_type
))
2444 emit_jump (label_rtx (node
->code_label
));
2446 else if (tree_int_cst_equal (node
->low
, node
->high
))
2448 /* Node is single valued. First see if the index expression matches
2449 this node and then check our children, if any. */
2451 do_jump_if_equal (mode
, index
,
2452 convert_modes (mode
, imode
,
2453 expand_normal (node
->low
),
2455 label_rtx (node
->code_label
), unsignedp
);
2457 if (node
->right
!= 0 && node
->left
!= 0)
2459 /* This node has children on both sides.
2460 Dispatch to one side or the other
2461 by comparing the index value with this node's value.
2462 If one subtree is bounded, check that one first,
2463 so we can avoid real branches in the tree. */
2465 if (node_is_bounded (node
->right
, index_type
))
2467 emit_cmp_and_jump_insns (index
,
2470 expand_normal (node
->high
),
2472 GT
, NULL_RTX
, mode
, unsignedp
,
2473 label_rtx (node
->right
->code_label
));
2474 emit_case_nodes (index
, node
->left
, default_label
, index_type
);
2477 else if (node_is_bounded (node
->left
, index_type
))
2479 emit_cmp_and_jump_insns (index
,
2482 expand_normal (node
->high
),
2484 LT
, NULL_RTX
, mode
, unsignedp
,
2485 label_rtx (node
->left
->code_label
));
2486 emit_case_nodes (index
, node
->right
, default_label
, index_type
);
2489 /* If both children are single-valued cases with no
2490 children, finish up all the work. This way, we can save
2491 one ordered comparison. */
2492 else if (tree_int_cst_equal (node
->right
->low
, node
->right
->high
)
2493 && node
->right
->left
== 0
2494 && node
->right
->right
== 0
2495 && tree_int_cst_equal (node
->left
->low
, node
->left
->high
)
2496 && node
->left
->left
== 0
2497 && node
->left
->right
== 0)
2499 /* Neither node is bounded. First distinguish the two sides;
2500 then emit the code for one side at a time. */
2502 /* See if the value matches what the right hand side
2504 do_jump_if_equal (mode
, index
,
2505 convert_modes (mode
, imode
,
2506 expand_normal (node
->right
->low
),
2508 label_rtx (node
->right
->code_label
),
2511 /* See if the value matches what the left hand side
2513 do_jump_if_equal (mode
, index
,
2514 convert_modes (mode
, imode
,
2515 expand_normal (node
->left
->low
),
2517 label_rtx (node
->left
->code_label
),
2523 /* Neither node is bounded. First distinguish the two sides;
2524 then emit the code for one side at a time. */
2527 = build_decl (CURR_INSN_LOCATION
,
2528 LABEL_DECL
, NULL_TREE
, NULL_TREE
);
2530 /* See if the value is on the right. */
2531 emit_cmp_and_jump_insns (index
,
2534 expand_normal (node
->high
),
2536 GT
, NULL_RTX
, mode
, unsignedp
,
2537 label_rtx (test_label
));
2539 /* Value must be on the left.
2540 Handle the left-hand subtree. */
2541 emit_case_nodes (index
, node
->left
, default_label
, index_type
);
2542 /* If left-hand subtree does nothing,
2545 emit_jump (default_label
);
2547 /* Code branches here for the right-hand subtree. */
2548 expand_label (test_label
);
2549 emit_case_nodes (index
, node
->right
, default_label
, index_type
);
2553 else if (node
->right
!= 0 && node
->left
== 0)
2555 /* Here we have a right child but no left so we issue a conditional
2556 branch to default and process the right child.
2558 Omit the conditional branch to default if the right child
2559 does not have any children and is single valued; it would
2560 cost too much space to save so little time. */
2562 if (node
->right
->right
|| node
->right
->left
2563 || !tree_int_cst_equal (node
->right
->low
, node
->right
->high
))
2565 if (!node_has_low_bound (node
, index_type
))
2567 emit_cmp_and_jump_insns (index
,
2570 expand_normal (node
->high
),
2572 LT
, NULL_RTX
, mode
, unsignedp
,
2576 emit_case_nodes (index
, node
->right
, default_label
, index_type
);
2579 /* We cannot process node->right normally
2580 since we haven't ruled out the numbers less than
2581 this node's value. So handle node->right explicitly. */
2582 do_jump_if_equal (mode
, index
,
2585 expand_normal (node
->right
->low
),
2587 label_rtx (node
->right
->code_label
), unsignedp
);
2590 else if (node
->right
== 0 && node
->left
!= 0)
2592 /* Just one subtree, on the left. */
2593 if (node
->left
->left
|| node
->left
->right
2594 || !tree_int_cst_equal (node
->left
->low
, node
->left
->high
))
2596 if (!node_has_high_bound (node
, index_type
))
2598 emit_cmp_and_jump_insns (index
,
2601 expand_normal (node
->high
),
2603 GT
, NULL_RTX
, mode
, unsignedp
,
2607 emit_case_nodes (index
, node
->left
, default_label
, index_type
);
2610 /* We cannot process node->left normally
2611 since we haven't ruled out the numbers less than
2612 this node's value. So handle node->left explicitly. */
2613 do_jump_if_equal (mode
, index
,
2616 expand_normal (node
->left
->low
),
2618 label_rtx (node
->left
->code_label
), unsignedp
);
2623 /* Node is a range. These cases are very similar to those for a single
2624 value, except that we do not start by testing whether this node
2625 is the one to branch to. */
2627 if (node
->right
!= 0 && node
->left
!= 0)
2629 /* Node has subtrees on both sides.
2630 If the right-hand subtree is bounded,
2631 test for it first, since we can go straight there.
2632 Otherwise, we need to make a branch in the control structure,
2633 then handle the two subtrees. */
2634 tree test_label
= 0;
2636 if (node_is_bounded (node
->right
, index_type
))
2637 /* Right hand node is fully bounded so we can eliminate any
2638 testing and branch directly to the target code. */
2639 emit_cmp_and_jump_insns (index
,
2642 expand_normal (node
->high
),
2644 GT
, NULL_RTX
, mode
, unsignedp
,
2645 label_rtx (node
->right
->code_label
));
2648 /* Right hand node requires testing.
2649 Branch to a label where we will handle it later. */
2651 test_label
= build_decl (CURR_INSN_LOCATION
,
2652 LABEL_DECL
, NULL_TREE
, NULL_TREE
);
2653 emit_cmp_and_jump_insns (index
,
2656 expand_normal (node
->high
),
2658 GT
, NULL_RTX
, mode
, unsignedp
,
2659 label_rtx (test_label
));
2662 /* Value belongs to this node or to the left-hand subtree. */
2664 emit_cmp_and_jump_insns (index
,
2667 expand_normal (node
->low
),
2669 GE
, NULL_RTX
, mode
, unsignedp
,
2670 label_rtx (node
->code_label
));
2672 /* Handle the left-hand subtree. */
2673 emit_case_nodes (index
, node
->left
, default_label
, index_type
);
2675 /* If right node had to be handled later, do that now. */
2679 /* If the left-hand subtree fell through,
2680 don't let it fall into the right-hand subtree. */
2682 emit_jump (default_label
);
2684 expand_label (test_label
);
2685 emit_case_nodes (index
, node
->right
, default_label
, index_type
);
2689 else if (node
->right
!= 0 && node
->left
== 0)
2691 /* Deal with values to the left of this node,
2692 if they are possible. */
2693 if (!node_has_low_bound (node
, index_type
))
2695 emit_cmp_and_jump_insns (index
,
2698 expand_normal (node
->low
),
2700 LT
, NULL_RTX
, mode
, unsignedp
,
2704 /* Value belongs to this node or to the right-hand subtree. */
2706 emit_cmp_and_jump_insns (index
,
2709 expand_normal (node
->high
),
2711 LE
, NULL_RTX
, mode
, unsignedp
,
2712 label_rtx (node
->code_label
));
2714 emit_case_nodes (index
, node
->right
, default_label
, index_type
);
2717 else if (node
->right
== 0 && node
->left
!= 0)
2719 /* Deal with values to the right of this node,
2720 if they are possible. */
2721 if (!node_has_high_bound (node
, index_type
))
2723 emit_cmp_and_jump_insns (index
,
2726 expand_normal (node
->high
),
2728 GT
, NULL_RTX
, mode
, unsignedp
,
2732 /* Value belongs to this node or to the left-hand subtree. */
2734 emit_cmp_and_jump_insns (index
,
2737 expand_normal (node
->low
),
2739 GE
, NULL_RTX
, mode
, unsignedp
,
2740 label_rtx (node
->code_label
));
2742 emit_case_nodes (index
, node
->left
, default_label
, index_type
);
2747 /* Node has no children so we check low and high bounds to remove
2748 redundant tests. Only one of the bounds can exist,
2749 since otherwise this node is bounded--a case tested already. */
2750 int high_bound
= node_has_high_bound (node
, index_type
);
2751 int low_bound
= node_has_low_bound (node
, index_type
);
2753 if (!high_bound
&& low_bound
)
2755 emit_cmp_and_jump_insns (index
,
2758 expand_normal (node
->high
),
2760 GT
, NULL_RTX
, mode
, unsignedp
,
2764 else if (!low_bound
&& high_bound
)
2766 emit_cmp_and_jump_insns (index
,
2769 expand_normal (node
->low
),
2771 LT
, NULL_RTX
, mode
, unsignedp
,
2774 else if (!low_bound
&& !high_bound
)
2776 /* Widen LOW and HIGH to the same width as INDEX. */
2777 tree type
= lang_hooks
.types
.type_for_mode (mode
, unsignedp
);
2778 tree low
= build1 (CONVERT_EXPR
, type
, node
->low
);
2779 tree high
= build1 (CONVERT_EXPR
, type
, node
->high
);
2780 rtx low_rtx
, new_index
, new_bound
;
2782 /* Instead of doing two branches, emit one unsigned branch for
2783 (index-low) > (high-low). */
2784 low_rtx
= expand_expr (low
, NULL_RTX
, mode
, EXPAND_NORMAL
);
2785 new_index
= expand_simple_binop (mode
, MINUS
, index
, low_rtx
,
2786 NULL_RTX
, unsignedp
,
2788 new_bound
= expand_expr (fold_build2 (MINUS_EXPR
, type
,
2790 NULL_RTX
, mode
, EXPAND_NORMAL
);
2792 emit_cmp_and_jump_insns (new_index
, new_bound
, GT
, NULL_RTX
,
2793 mode
, 1, default_label
);
2796 emit_jump (label_rtx (node
->code_label
));