1 /* Register to Stack convert for GNU compiler.
2 Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
3 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 GCC is distributed in the hope that it will be useful, but WITHOUT
13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
15 License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
22 /* This pass converts stack-like registers from the "flat register
23 file" model that gcc uses, to a stack convention that the 387 uses.
25 * The form of the input:
27 On input, the function consists of insn that have had their
28 registers fully allocated to a set of "virtual" registers. Note that
29 the word "virtual" is used differently here than elsewhere in gcc: for
30 each virtual stack reg, there is a hard reg, but the mapping between
31 them is not known until this pass is run. On output, hard register
32 numbers have been substituted, and various pop and exchange insns have
33 been emitted. The hard register numbers and the virtual register
34 numbers completely overlap - before this pass, all stack register
35 numbers are virtual, and afterward they are all hard.
37 The virtual registers can be manipulated normally by gcc, and their
38 semantics are the same as for normal registers. After the hard
39 register numbers are substituted, the semantics of an insn containing
40 stack-like regs are not the same as for an insn with normal regs: for
41 instance, it is not safe to delete an insn that appears to be a no-op
42 move. In general, no insn containing hard regs should be changed
43 after this pass is done.
45 * The form of the output:
47 After this pass, hard register numbers represent the distance from
48 the current top of stack to the desired register. A reference to
49 FIRST_STACK_REG references the top of stack, FIRST_STACK_REG + 1,
50 represents the register just below that, and so forth. Also, REG_DEAD
51 notes indicate whether or not a stack register should be popped.
53 A "swap" insn looks like a parallel of two patterns, where each
54 pattern is a SET: one sets A to B, the other B to A.
56 A "push" or "load" insn is a SET whose SET_DEST is FIRST_STACK_REG
57 and whose SET_DEST is REG or MEM. Any other SET_DEST, such as PLUS,
58 will replace the existing stack top, not push a new value.
60 A store insn is a SET whose SET_DEST is FIRST_STACK_REG, and whose
61 SET_SRC is REG or MEM.
63 The case where the SET_SRC and SET_DEST are both FIRST_STACK_REG
64 appears ambiguous. As a special case, the presence of a REG_DEAD note
65 for FIRST_STACK_REG differentiates between a load insn and a pop.
67 If a REG_DEAD is present, the insn represents a "pop" that discards
68 the top of the register stack. If there is no REG_DEAD note, then the
69 insn represents a "dup" or a push of the current top of stack onto the
74 Existing REG_DEAD and REG_UNUSED notes for stack registers are
75 deleted and recreated from scratch. REG_DEAD is never created for a
76 SET_DEST, only REG_UNUSED.
80 There are several rules on the usage of stack-like regs in
81 asm_operands insns. These rules apply only to the operands that are
84 1. Given a set of input regs that die in an asm_operands, it is
85 necessary to know which are implicitly popped by the asm, and
86 which must be explicitly popped by gcc.
88 An input reg that is implicitly popped by the asm must be
89 explicitly clobbered, unless it is constrained to match an
92 2. For any input reg that is implicitly popped by an asm, it is
93 necessary to know how to adjust the stack to compensate for the pop.
94 If any non-popped input is closer to the top of the reg-stack than
95 the implicitly popped reg, it would not be possible to know what the
96 stack looked like - it's not clear how the rest of the stack "slides
99 All implicitly popped input regs must be closer to the top of
100 the reg-stack than any input that is not implicitly popped.
102 3. It is possible that if an input dies in an insn, reload might
103 use the input reg for an output reload. Consider this example:
105 asm ("foo" : "=t" (a) : "f" (b));
107 This asm says that input B is not popped by the asm, and that
108 the asm pushes a result onto the reg-stack, ie, the stack is one
109 deeper after the asm than it was before. But, it is possible that
110 reload will think that it can use the same reg for both the input and
111 the output, if input B dies in this insn.
113 If any input operand uses the "f" constraint, all output reg
114 constraints must use the "&" earlyclobber.
116 The asm above would be written as
118 asm ("foo" : "=&t" (a) : "f" (b));
120 4. Some operands need to be in particular places on the stack. All
121 output operands fall in this category - there is no other way to
122 know which regs the outputs appear in unless the user indicates
123 this in the constraints.
125 Output operands must specifically indicate which reg an output
126 appears in after an asm. "=f" is not allowed: the operand
127 constraints must select a class with a single reg.
129 5. Output operands may not be "inserted" between existing stack regs.
130 Since no 387 opcode uses a read/write operand, all output operands
131 are dead before the asm_operands, and are pushed by the asm_operands.
132 It makes no sense to push anywhere but the top of the reg-stack.
134 Output operands must start at the top of the reg-stack: output
135 operands may not "skip" a reg.
137 6. Some asm statements may need extra stack space for internal
138 calculations. This can be guaranteed by clobbering stack registers
139 unrelated to the inputs and outputs.
141 Here are a couple of reasonable asms to want to write. This asm
142 takes one input, which is internally popped, and produces two outputs.
144 asm ("fsincos" : "=t" (cos), "=u" (sin) : "0" (inp));
146 This asm takes two inputs, which are popped by the fyl2xp1 opcode,
147 and replaces them with one output. The user must code the "st(1)"
148 clobber for reg-stack.c to know that fyl2xp1 pops both inputs.
150 asm ("fyl2xp1" : "=t" (result) : "0" (x), "u" (y) : "st(1)");
156 #include "coretypes.h"
161 #include "function.h"
162 #include "insn-config.h"
164 #include "hard-reg-set.h"
169 #include "basic-block.h"
174 /* We use this array to cache info about insns, because otherwise we
175 spend too much time in stack_regs_mentioned_p.
177 Indexed by insn UIDs. A value of zero is uninitialized, one indicates
178 the insn uses stack registers, two indicates the insn does not use
180 static GTY(()) varray_type stack_regs_mentioned_data
;
184 #define REG_STACK_SIZE (LAST_STACK_REG - FIRST_STACK_REG + 1)
186 /* This is the basic stack record. TOP is an index into REG[] such
187 that REG[TOP] is the top of stack. If TOP is -1 the stack is empty.
189 If TOP is -2, REG[] is not yet initialized. Stack initialization
190 consists of placing each live reg in array `reg' and setting `top'
193 REG_SET indicates which registers are live. */
195 typedef struct stack_def
197 int top
; /* index to top stack element */
198 HARD_REG_SET reg_set
; /* set of live registers */
199 unsigned char reg
[REG_STACK_SIZE
];/* register - stack mapping */
202 /* This is used to carry information about basic blocks. It is
203 attached to the AUX field of the standard CFG block. */
205 typedef struct block_info_def
207 struct stack_def stack_in
; /* Input stack configuration. */
208 struct stack_def stack_out
; /* Output stack configuration. */
209 HARD_REG_SET out_reg_set
; /* Stack regs live on output. */
210 int done
; /* True if block already converted. */
211 int predecessors
; /* Number of predecessors that needs
215 #define BLOCK_INFO(B) ((block_info) (B)->aux)
217 /* Passed to change_stack to indicate where to emit insns. */
224 /* The block we're currently working on. */
225 static basic_block current_block
;
227 /* This is the register file for all register after conversion. */
229 FP_mode_reg
[LAST_STACK_REG
+1-FIRST_STACK_REG
][(int) MAX_MACHINE_MODE
];
231 #define FP_MODE_REG(regno,mode) \
232 (FP_mode_reg[(regno)-FIRST_STACK_REG][(int) (mode)])
234 /* Used to initialize uninitialized registers. */
237 /* Forward declarations */
239 static int stack_regs_mentioned_p
PARAMS ((rtx pat
));
240 static void straighten_stack
PARAMS ((rtx
, stack
));
241 static void pop_stack
PARAMS ((stack
, int));
242 static rtx
*get_true_reg
PARAMS ((rtx
*));
244 static int check_asm_stack_operands
PARAMS ((rtx
));
245 static int get_asm_operand_n_inputs
PARAMS ((rtx
));
246 static rtx stack_result
PARAMS ((tree
));
247 static void replace_reg
PARAMS ((rtx
*, int));
248 static void remove_regno_note
PARAMS ((rtx
, enum reg_note
,
250 static int get_hard_regnum
PARAMS ((stack
, rtx
));
251 static rtx emit_pop_insn
PARAMS ((rtx
, stack
, rtx
,
253 static void emit_swap_insn
PARAMS ((rtx
, stack
, rtx
));
254 static void move_for_stack_reg
PARAMS ((rtx
, stack
, rtx
));
255 static int swap_rtx_condition_1
PARAMS ((rtx
));
256 static int swap_rtx_condition
PARAMS ((rtx
));
257 static void compare_for_stack_reg
PARAMS ((rtx
, stack
, rtx
));
258 static void subst_stack_regs_pat
PARAMS ((rtx
, stack
, rtx
));
259 static void subst_asm_stack_regs
PARAMS ((rtx
, stack
));
260 static void subst_stack_regs
PARAMS ((rtx
, stack
));
261 static void change_stack
PARAMS ((rtx
, stack
, stack
,
263 static int convert_regs_entry
PARAMS ((void));
264 static void convert_regs_exit
PARAMS ((void));
265 static int convert_regs_1
PARAMS ((FILE *, basic_block
));
266 static int convert_regs_2
PARAMS ((FILE *, basic_block
));
267 static int convert_regs
PARAMS ((FILE *));
268 static void print_stack
PARAMS ((FILE *, stack
));
269 static rtx next_flags_user
PARAMS ((rtx
));
270 static void record_label_references
PARAMS ((rtx
, rtx
));
271 static bool compensate_edge
PARAMS ((edge
, FILE *));
273 /* Return nonzero if any stack register is mentioned somewhere within PAT. */
276 stack_regs_mentioned_p (pat
)
282 if (STACK_REG_P (pat
))
285 fmt
= GET_RTX_FORMAT (GET_CODE (pat
));
286 for (i
= GET_RTX_LENGTH (GET_CODE (pat
)) - 1; i
>= 0; i
--)
292 for (j
= XVECLEN (pat
, i
) - 1; j
>= 0; j
--)
293 if (stack_regs_mentioned_p (XVECEXP (pat
, i
, j
)))
296 else if (fmt
[i
] == 'e' && stack_regs_mentioned_p (XEXP (pat
, i
)))
303 /* Return nonzero if INSN mentions stacked registers, else return zero. */
306 stack_regs_mentioned (insn
)
309 unsigned int uid
, max
;
312 if (! INSN_P (insn
) || !stack_regs_mentioned_data
)
315 uid
= INSN_UID (insn
);
316 max
= VARRAY_SIZE (stack_regs_mentioned_data
);
319 /* Allocate some extra size to avoid too many reallocs, but
320 do not grow too quickly. */
321 max
= uid
+ uid
/ 20;
322 VARRAY_GROW (stack_regs_mentioned_data
, max
);
325 test
= VARRAY_CHAR (stack_regs_mentioned_data
, uid
);
328 /* This insn has yet to be examined. Do so now. */
329 test
= stack_regs_mentioned_p (PATTERN (insn
)) ? 1 : 2;
330 VARRAY_CHAR (stack_regs_mentioned_data
, uid
) = test
;
336 static rtx ix86_flags_rtx
;
339 next_flags_user (insn
)
342 /* Search forward looking for the first use of this value.
343 Stop at block boundaries. */
345 while (insn
!= current_block
->end
)
347 insn
= NEXT_INSN (insn
);
349 if (INSN_P (insn
) && reg_mentioned_p (ix86_flags_rtx
, PATTERN (insn
)))
352 if (GET_CODE (insn
) == CALL_INSN
)
358 /* Reorganize the stack into ascending numbers,
362 straighten_stack (insn
, regstack
)
366 struct stack_def temp_stack
;
369 /* If there is only a single register on the stack, then the stack is
370 already in increasing order and no reorganization is needed.
372 Similarly if the stack is empty. */
373 if (regstack
->top
<= 0)
376 COPY_HARD_REG_SET (temp_stack
.reg_set
, regstack
->reg_set
);
378 for (top
= temp_stack
.top
= regstack
->top
; top
>= 0; top
--)
379 temp_stack
.reg
[top
] = FIRST_STACK_REG
+ temp_stack
.top
- top
;
381 change_stack (insn
, regstack
, &temp_stack
, EMIT_AFTER
);
384 /* Pop a register from the stack. */
387 pop_stack (regstack
, regno
)
391 int top
= regstack
->top
;
393 CLEAR_HARD_REG_BIT (regstack
->reg_set
, regno
);
395 /* If regno was not at the top of stack then adjust stack. */
396 if (regstack
->reg
[top
] != regno
)
399 for (i
= regstack
->top
; i
>= 0; i
--)
400 if (regstack
->reg
[i
] == regno
)
403 for (j
= i
; j
< top
; j
++)
404 regstack
->reg
[j
] = regstack
->reg
[j
+ 1];
410 /* Convert register usage from "flat" register file usage to a "stack
411 register file. FIRST is the first insn in the function, FILE is the
414 Construct a CFG and run life analysis. Then convert each insn one
415 by one. Run a last cleanup_cfg pass, if optimizing, to eliminate
416 code duplication created when the converter inserts pop insns on
420 reg_to_stack (first
, file
)
428 /* Clean up previous run. */
429 stack_regs_mentioned_data
= 0;
434 /* See if there is something to do. Flow analysis is quite
435 expensive so we might save some compilation time. */
436 for (i
= FIRST_STACK_REG
; i
<= LAST_STACK_REG
; i
++)
437 if (regs_ever_live
[i
])
439 if (i
> LAST_STACK_REG
)
442 /* Ok, floating point instructions exist. If not optimizing,
443 build the CFG and run life analysis.
444 Also need to rebuild life when superblock scheduling is done
445 as it don't update liveness yet. */
447 || (flag_sched2_use_superblocks
448 && flag_schedule_insns_after_reload
))
450 count_or_remove_death_notes (NULL
, 1);
451 life_analysis (first
, file
, PROP_DEATH_NOTES
);
453 mark_dfs_back_edges ();
455 /* Set up block info for each basic block. */
456 alloc_aux_for_blocks (sizeof (struct block_info_def
));
457 FOR_EACH_BB_REVERSE (bb
)
460 for (e
= bb
->pred
; e
; e
=e
->pred_next
)
461 if (!(e
->flags
& EDGE_DFS_BACK
)
462 && e
->src
!= ENTRY_BLOCK_PTR
)
463 BLOCK_INFO (bb
)->predecessors
++;
466 /* Create the replacement registers up front. */
467 for (i
= FIRST_STACK_REG
; i
<= LAST_STACK_REG
; i
++)
469 enum machine_mode mode
;
470 for (mode
= GET_CLASS_NARROWEST_MODE (MODE_FLOAT
);
472 mode
= GET_MODE_WIDER_MODE (mode
))
473 FP_MODE_REG (i
, mode
) = gen_rtx_REG (mode
, i
);
474 for (mode
= GET_CLASS_NARROWEST_MODE (MODE_COMPLEX_FLOAT
);
476 mode
= GET_MODE_WIDER_MODE (mode
))
477 FP_MODE_REG (i
, mode
) = gen_rtx_REG (mode
, i
);
480 ix86_flags_rtx
= gen_rtx_REG (CCmode
, FLAGS_REG
);
482 /* A QNaN for initializing uninitialized variables.
484 ??? We can't load from constant memory in PIC mode, because
485 we're inserting these instructions before the prologue and
486 the PIC register hasn't been set up. In that case, fall back
487 on zero, which we can get from `ldz'. */
490 nan
= CONST0_RTX (SFmode
);
493 nan
= gen_lowpart (SFmode
, GEN_INT (0x7fc00000));
494 nan
= force_const_mem (SFmode
, nan
);
497 /* Allocate a cache for stack_regs_mentioned. */
498 max_uid
= get_max_uid ();
499 VARRAY_CHAR_INIT (stack_regs_mentioned_data
, max_uid
+ 1,
500 "stack_regs_mentioned cache");
504 free_aux_for_blocks ();
508 /* Check PAT, which is in INSN, for LABEL_REFs. Add INSN to the
509 label's chain of references, and note which insn contains each
513 record_label_references (insn
, pat
)
516 enum rtx_code code
= GET_CODE (pat
);
520 if (code
== LABEL_REF
)
522 rtx label
= XEXP (pat
, 0);
525 if (GET_CODE (label
) != CODE_LABEL
)
528 /* If this is an undefined label, LABEL_REFS (label) contains
530 if (INSN_UID (label
) == 0)
533 /* Don't make a duplicate in the code_label's chain. */
535 for (ref
= LABEL_REFS (label
);
537 ref
= LABEL_NEXTREF (ref
))
538 if (CONTAINING_INSN (ref
) == insn
)
541 CONTAINING_INSN (pat
) = insn
;
542 LABEL_NEXTREF (pat
) = LABEL_REFS (label
);
543 LABEL_REFS (label
) = pat
;
548 fmt
= GET_RTX_FORMAT (code
);
549 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
552 record_label_references (insn
, XEXP (pat
, i
));
556 for (j
= 0; j
< XVECLEN (pat
, i
); j
++)
557 record_label_references (insn
, XVECEXP (pat
, i
, j
));
562 /* Return a pointer to the REG expression within PAT. If PAT is not a
563 REG, possible enclosed by a conversion rtx, return the inner part of
564 PAT that stopped the search. */
571 switch (GET_CODE (*pat
))
574 /* Eliminate FP subregister accesses in favor of the
575 actual FP register in use. */
578 if (FP_REG_P (subreg
= SUBREG_REG (*pat
)))
580 int regno_off
= subreg_regno_offset (REGNO (subreg
),
584 *pat
= FP_MODE_REG (REGNO (subreg
) + regno_off
,
593 pat
= & XEXP (*pat
, 0);
597 /* There are many rules that an asm statement for stack-like regs must
598 follow. Those rules are explained at the top of this file: the rule
599 numbers below refer to that explanation. */
602 check_asm_stack_operands (insn
)
607 int malformed_asm
= 0;
608 rtx body
= PATTERN (insn
);
610 char reg_used_as_output
[FIRST_PSEUDO_REGISTER
];
611 char implicitly_dies
[FIRST_PSEUDO_REGISTER
];
614 rtx
*clobber_reg
= 0;
615 int n_inputs
, n_outputs
;
617 /* Find out what the constraints require. If no constraint
618 alternative matches, this asm is malformed. */
620 constrain_operands (1);
621 alt
= which_alternative
;
623 preprocess_constraints ();
625 n_inputs
= get_asm_operand_n_inputs (body
);
626 n_outputs
= recog_data
.n_operands
- n_inputs
;
631 /* Avoid further trouble with this insn. */
632 PATTERN (insn
) = gen_rtx_USE (VOIDmode
, const0_rtx
);
636 /* Strip SUBREGs here to make the following code simpler. */
637 for (i
= 0; i
< recog_data
.n_operands
; i
++)
638 if (GET_CODE (recog_data
.operand
[i
]) == SUBREG
639 && GET_CODE (SUBREG_REG (recog_data
.operand
[i
])) == REG
)
640 recog_data
.operand
[i
] = SUBREG_REG (recog_data
.operand
[i
]);
642 /* Set up CLOBBER_REG. */
646 if (GET_CODE (body
) == PARALLEL
)
648 clobber_reg
= (rtx
*) alloca (XVECLEN (body
, 0) * sizeof (rtx
));
650 for (i
= 0; i
< XVECLEN (body
, 0); i
++)
651 if (GET_CODE (XVECEXP (body
, 0, i
)) == CLOBBER
)
653 rtx clobber
= XVECEXP (body
, 0, i
);
654 rtx reg
= XEXP (clobber
, 0);
656 if (GET_CODE (reg
) == SUBREG
&& GET_CODE (SUBREG_REG (reg
)) == REG
)
657 reg
= SUBREG_REG (reg
);
659 if (STACK_REG_P (reg
))
661 clobber_reg
[n_clobbers
] = reg
;
667 /* Enforce rule #4: Output operands must specifically indicate which
668 reg an output appears in after an asm. "=f" is not allowed: the
669 operand constraints must select a class with a single reg.
671 Also enforce rule #5: Output operands must start at the top of
672 the reg-stack: output operands may not "skip" a reg. */
674 memset (reg_used_as_output
, 0, sizeof (reg_used_as_output
));
675 for (i
= 0; i
< n_outputs
; i
++)
676 if (STACK_REG_P (recog_data
.operand
[i
]))
678 if (reg_class_size
[(int) recog_op_alt
[i
][alt
].class] != 1)
680 error_for_asm (insn
, "output constraint %d must specify a single register", i
);
687 for (j
= 0; j
< n_clobbers
; j
++)
688 if (REGNO (recog_data
.operand
[i
]) == REGNO (clobber_reg
[j
]))
690 error_for_asm (insn
, "output constraint %d cannot be specified together with \"%s\" clobber",
691 i
, reg_names
[REGNO (clobber_reg
[j
])]);
696 reg_used_as_output
[REGNO (recog_data
.operand
[i
])] = 1;
701 /* Search for first non-popped reg. */
702 for (i
= FIRST_STACK_REG
; i
< LAST_STACK_REG
+ 1; i
++)
703 if (! reg_used_as_output
[i
])
706 /* If there are any other popped regs, that's an error. */
707 for (; i
< LAST_STACK_REG
+ 1; i
++)
708 if (reg_used_as_output
[i
])
711 if (i
!= LAST_STACK_REG
+ 1)
713 error_for_asm (insn
, "output regs must be grouped at top of stack");
717 /* Enforce rule #2: All implicitly popped input regs must be closer
718 to the top of the reg-stack than any input that is not implicitly
721 memset (implicitly_dies
, 0, sizeof (implicitly_dies
));
722 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
723 if (STACK_REG_P (recog_data
.operand
[i
]))
725 /* An input reg is implicitly popped if it is tied to an
726 output, or if there is a CLOBBER for it. */
729 for (j
= 0; j
< n_clobbers
; j
++)
730 if (operands_match_p (clobber_reg
[j
], recog_data
.operand
[i
]))
733 if (j
< n_clobbers
|| recog_op_alt
[i
][alt
].matches
>= 0)
734 implicitly_dies
[REGNO (recog_data
.operand
[i
])] = 1;
737 /* Search for first non-popped reg. */
738 for (i
= FIRST_STACK_REG
; i
< LAST_STACK_REG
+ 1; i
++)
739 if (! implicitly_dies
[i
])
742 /* If there are any other popped regs, that's an error. */
743 for (; i
< LAST_STACK_REG
+ 1; i
++)
744 if (implicitly_dies
[i
])
747 if (i
!= LAST_STACK_REG
+ 1)
750 "implicitly popped regs must be grouped at top of stack");
754 /* Enforce rule #3: If any input operand uses the "f" constraint, all
755 output constraints must use the "&" earlyclobber.
757 ??? Detect this more deterministically by having constrain_asm_operands
758 record any earlyclobber. */
760 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
761 if (recog_op_alt
[i
][alt
].matches
== -1)
765 for (j
= 0; j
< n_outputs
; j
++)
766 if (operands_match_p (recog_data
.operand
[j
], recog_data
.operand
[i
]))
769 "output operand %d must use `&' constraint", j
);
776 /* Avoid further trouble with this insn. */
777 PATTERN (insn
) = gen_rtx_USE (VOIDmode
, const0_rtx
);
784 /* Calculate the number of inputs and outputs in BODY, an
785 asm_operands. N_OPERANDS is the total number of operands, and
786 N_INPUTS and N_OUTPUTS are pointers to ints into which the results are
790 get_asm_operand_n_inputs (body
)
793 if (GET_CODE (body
) == SET
&& GET_CODE (SET_SRC (body
)) == ASM_OPERANDS
)
794 return ASM_OPERANDS_INPUT_LENGTH (SET_SRC (body
));
796 else if (GET_CODE (body
) == ASM_OPERANDS
)
797 return ASM_OPERANDS_INPUT_LENGTH (body
);
799 else if (GET_CODE (body
) == PARALLEL
800 && GET_CODE (XVECEXP (body
, 0, 0)) == SET
)
801 return ASM_OPERANDS_INPUT_LENGTH (SET_SRC (XVECEXP (body
, 0, 0)));
803 else if (GET_CODE (body
) == PARALLEL
804 && GET_CODE (XVECEXP (body
, 0, 0)) == ASM_OPERANDS
)
805 return ASM_OPERANDS_INPUT_LENGTH (XVECEXP (body
, 0, 0));
810 /* If current function returns its result in an fp stack register,
811 return the REG. Otherwise, return 0. */
819 /* If the value is supposed to be returned in memory, then clearly
820 it is not returned in a stack register. */
821 if (aggregate_value_p (DECL_RESULT (decl
)))
824 result
= DECL_RTL_IF_SET (DECL_RESULT (decl
));
827 #ifdef FUNCTION_OUTGOING_VALUE
829 = FUNCTION_OUTGOING_VALUE (TREE_TYPE (DECL_RESULT (decl
)), decl
);
831 result
= FUNCTION_VALUE (TREE_TYPE (DECL_RESULT (decl
)), decl
);
835 return result
!= 0 && STACK_REG_P (result
) ? result
: 0;
840 * This section deals with stack register substitution, and forms the second
844 /* Replace REG, which is a pointer to a stack reg RTX, with an RTX for
845 the desired hard REGNO. */
848 replace_reg (reg
, regno
)
852 if (regno
< FIRST_STACK_REG
|| regno
> LAST_STACK_REG
853 || ! STACK_REG_P (*reg
))
856 switch (GET_MODE_CLASS (GET_MODE (*reg
)))
860 case MODE_COMPLEX_FLOAT
:;
863 *reg
= FP_MODE_REG (regno
, GET_MODE (*reg
));
866 /* Remove a note of type NOTE, which must be found, for register
867 number REGNO from INSN. Remove only one such note. */
870 remove_regno_note (insn
, note
, regno
)
875 rtx
*note_link
, this;
877 note_link
= ®_NOTES (insn
);
878 for (this = *note_link
; this; this = XEXP (this, 1))
879 if (REG_NOTE_KIND (this) == note
880 && REG_P (XEXP (this, 0)) && REGNO (XEXP (this, 0)) == regno
)
882 *note_link
= XEXP (this, 1);
886 note_link
= &XEXP (this, 1);
891 /* Find the hard register number of virtual register REG in REGSTACK.
892 The hard register number is relative to the top of the stack. -1 is
893 returned if the register is not found. */
896 get_hard_regnum (regstack
, reg
)
902 if (! STACK_REG_P (reg
))
905 for (i
= regstack
->top
; i
>= 0; i
--)
906 if (regstack
->reg
[i
] == REGNO (reg
))
909 return i
>= 0 ? (FIRST_STACK_REG
+ regstack
->top
- i
) : -1;
912 /* Emit an insn to pop virtual register REG before or after INSN.
913 REGSTACK is the stack state after INSN and is updated to reflect this
914 pop. WHEN is either emit_insn_before or emit_insn_after. A pop insn
915 is represented as a SET whose destination is the register to be popped
916 and source is the top of stack. A death note for the top of stack
917 cases the movdf pattern to pop. */
920 emit_pop_insn (insn
, regstack
, reg
, where
)
924 enum emit_where where
;
926 rtx pop_insn
, pop_rtx
;
929 /* For complex types take care to pop both halves. These may survive in
930 CLOBBER and USE expressions. */
931 if (COMPLEX_MODE_P (GET_MODE (reg
)))
933 rtx reg1
= FP_MODE_REG (REGNO (reg
), DFmode
);
934 rtx reg2
= FP_MODE_REG (REGNO (reg
) + 1, DFmode
);
937 if (get_hard_regnum (regstack
, reg1
) >= 0)
938 pop_insn
= emit_pop_insn (insn
, regstack
, reg1
, where
);
939 if (get_hard_regnum (regstack
, reg2
) >= 0)
940 pop_insn
= emit_pop_insn (insn
, regstack
, reg2
, where
);
946 hard_regno
= get_hard_regnum (regstack
, reg
);
948 if (hard_regno
< FIRST_STACK_REG
)
951 pop_rtx
= gen_rtx_SET (VOIDmode
, FP_MODE_REG (hard_regno
, DFmode
),
952 FP_MODE_REG (FIRST_STACK_REG
, DFmode
));
954 if (where
== EMIT_AFTER
)
955 pop_insn
= emit_insn_after (pop_rtx
, insn
);
957 pop_insn
= emit_insn_before (pop_rtx
, insn
);
960 = gen_rtx_EXPR_LIST (REG_DEAD
, FP_MODE_REG (FIRST_STACK_REG
, DFmode
),
961 REG_NOTES (pop_insn
));
963 regstack
->reg
[regstack
->top
- (hard_regno
- FIRST_STACK_REG
)]
964 = regstack
->reg
[regstack
->top
];
966 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (reg
));
971 /* Emit an insn before or after INSN to swap virtual register REG with
972 the top of stack. REGSTACK is the stack state before the swap, and
973 is updated to reflect the swap. A swap insn is represented as a
974 PARALLEL of two patterns: each pattern moves one reg to the other.
976 If REG is already at the top of the stack, no insn is emitted. */
979 emit_swap_insn (insn
, regstack
, reg
)
986 int tmp
, other_reg
; /* swap regno temps */
987 rtx i1
; /* the stack-reg insn prior to INSN */
988 rtx i1set
= NULL_RTX
; /* the SET rtx within I1 */
990 hard_regno
= get_hard_regnum (regstack
, reg
);
992 if (hard_regno
< FIRST_STACK_REG
)
994 if (hard_regno
== FIRST_STACK_REG
)
997 other_reg
= regstack
->top
- (hard_regno
- FIRST_STACK_REG
);
999 tmp
= regstack
->reg
[other_reg
];
1000 regstack
->reg
[other_reg
] = regstack
->reg
[regstack
->top
];
1001 regstack
->reg
[regstack
->top
] = tmp
;
1003 /* Find the previous insn involving stack regs, but don't pass a
1006 if (current_block
&& insn
!= current_block
->head
)
1008 rtx tmp
= PREV_INSN (insn
);
1009 rtx limit
= PREV_INSN (current_block
->head
);
1010 while (tmp
!= limit
)
1012 if (GET_CODE (tmp
) == CODE_LABEL
1013 || GET_CODE (tmp
) == CALL_INSN
1014 || NOTE_INSN_BASIC_BLOCK_P (tmp
)
1015 || (GET_CODE (tmp
) == INSN
1016 && stack_regs_mentioned (tmp
)))
1021 tmp
= PREV_INSN (tmp
);
1026 && (i1set
= single_set (i1
)) != NULL_RTX
)
1028 rtx i1src
= *get_true_reg (&SET_SRC (i1set
));
1029 rtx i1dest
= *get_true_reg (&SET_DEST (i1set
));
1031 /* If the previous register stack push was from the reg we are to
1032 swap with, omit the swap. */
1034 if (GET_CODE (i1dest
) == REG
&& REGNO (i1dest
) == FIRST_STACK_REG
1035 && GET_CODE (i1src
) == REG
1036 && REGNO (i1src
) == (unsigned) hard_regno
- 1
1037 && find_regno_note (i1
, REG_DEAD
, FIRST_STACK_REG
) == NULL_RTX
)
1040 /* If the previous insn wrote to the reg we are to swap with,
1043 if (GET_CODE (i1dest
) == REG
&& REGNO (i1dest
) == (unsigned) hard_regno
1044 && GET_CODE (i1src
) == REG
&& REGNO (i1src
) == FIRST_STACK_REG
1045 && find_regno_note (i1
, REG_DEAD
, FIRST_STACK_REG
) == NULL_RTX
)
1049 swap_rtx
= gen_swapxf (FP_MODE_REG (hard_regno
, XFmode
),
1050 FP_MODE_REG (FIRST_STACK_REG
, XFmode
));
1053 emit_insn_after (swap_rtx
, i1
);
1054 else if (current_block
)
1055 emit_insn_before (swap_rtx
, current_block
->head
);
1057 emit_insn_before (swap_rtx
, insn
);
1060 /* Handle a move to or from a stack register in PAT, which is in INSN.
1061 REGSTACK is the current stack. */
1064 move_for_stack_reg (insn
, regstack
, pat
)
1069 rtx
*psrc
= get_true_reg (&SET_SRC (pat
));
1070 rtx
*pdest
= get_true_reg (&SET_DEST (pat
));
1074 src
= *psrc
; dest
= *pdest
;
1076 if (STACK_REG_P (src
) && STACK_REG_P (dest
))
1078 /* Write from one stack reg to another. If SRC dies here, then
1079 just change the register mapping and delete the insn. */
1081 note
= find_regno_note (insn
, REG_DEAD
, REGNO (src
));
1086 /* If this is a no-op move, there must not be a REG_DEAD note. */
1087 if (REGNO (src
) == REGNO (dest
))
1090 for (i
= regstack
->top
; i
>= 0; i
--)
1091 if (regstack
->reg
[i
] == REGNO (src
))
1094 /* The source must be live, and the dest must be dead. */
1095 if (i
< 0 || get_hard_regnum (regstack
, dest
) >= FIRST_STACK_REG
)
1098 /* It is possible that the dest is unused after this insn.
1099 If so, just pop the src. */
1101 if (find_regno_note (insn
, REG_UNUSED
, REGNO (dest
)))
1103 emit_pop_insn (insn
, regstack
, src
, EMIT_AFTER
);
1109 regstack
->reg
[i
] = REGNO (dest
);
1111 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (dest
));
1112 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (src
));
1119 /* The source reg does not die. */
1121 /* If this appears to be a no-op move, delete it, or else it
1122 will confuse the machine description output patterns. But if
1123 it is REG_UNUSED, we must pop the reg now, as per-insn processing
1124 for REG_UNUSED will not work for deleted insns. */
1126 if (REGNO (src
) == REGNO (dest
))
1128 if (find_regno_note (insn
, REG_UNUSED
, REGNO (dest
)))
1129 emit_pop_insn (insn
, regstack
, dest
, EMIT_AFTER
);
1135 /* The destination ought to be dead. */
1136 if (get_hard_regnum (regstack
, dest
) >= FIRST_STACK_REG
)
1139 replace_reg (psrc
, get_hard_regnum (regstack
, src
));
1141 regstack
->reg
[++regstack
->top
] = REGNO (dest
);
1142 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (dest
));
1143 replace_reg (pdest
, FIRST_STACK_REG
);
1145 else if (STACK_REG_P (src
))
1147 /* Save from a stack reg to MEM, or possibly integer reg. Since
1148 only top of stack may be saved, emit an exchange first if
1151 emit_swap_insn (insn
, regstack
, src
);
1153 note
= find_regno_note (insn
, REG_DEAD
, REGNO (src
));
1156 replace_reg (&XEXP (note
, 0), FIRST_STACK_REG
);
1158 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (src
));
1160 else if ((GET_MODE (src
) == XFmode
|| GET_MODE (src
) == TFmode
)
1161 && regstack
->top
< REG_STACK_SIZE
- 1)
1163 /* A 387 cannot write an XFmode value to a MEM without
1164 clobbering the source reg. The output code can handle
1165 this by reading back the value from the MEM.
1166 But it is more efficient to use a temp register if one is
1167 available. Push the source value here if the register
1168 stack is not full, and then write the value to memory via
1170 rtx push_rtx
, push_insn
;
1171 rtx top_stack_reg
= FP_MODE_REG (FIRST_STACK_REG
, GET_MODE (src
));
1173 if (GET_MODE (src
) == TFmode
)
1174 push_rtx
= gen_movtf (top_stack_reg
, top_stack_reg
);
1176 push_rtx
= gen_movxf (top_stack_reg
, top_stack_reg
);
1177 push_insn
= emit_insn_before (push_rtx
, insn
);
1178 REG_NOTES (insn
) = gen_rtx_EXPR_LIST (REG_DEAD
, top_stack_reg
,
1182 replace_reg (psrc
, FIRST_STACK_REG
);
1184 else if (STACK_REG_P (dest
))
1186 /* Load from MEM, or possibly integer REG or constant, into the
1187 stack regs. The actual target is always the top of the
1188 stack. The stack mapping is changed to reflect that DEST is
1189 now at top of stack. */
1191 /* The destination ought to be dead. */
1192 if (get_hard_regnum (regstack
, dest
) >= FIRST_STACK_REG
)
1195 if (regstack
->top
>= REG_STACK_SIZE
)
1198 regstack
->reg
[++regstack
->top
] = REGNO (dest
);
1199 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (dest
));
1200 replace_reg (pdest
, FIRST_STACK_REG
);
1206 /* Swap the condition on a branch, if there is one. Return true if we
1207 found a condition to swap. False if the condition was not used as
1211 swap_rtx_condition_1 (pat
)
1217 if (GET_RTX_CLASS (GET_CODE (pat
)) == '<')
1219 PUT_CODE (pat
, swap_condition (GET_CODE (pat
)));
1224 fmt
= GET_RTX_FORMAT (GET_CODE (pat
));
1225 for (i
= GET_RTX_LENGTH (GET_CODE (pat
)) - 1; i
>= 0; i
--)
1231 for (j
= XVECLEN (pat
, i
) - 1; j
>= 0; j
--)
1232 r
|= swap_rtx_condition_1 (XVECEXP (pat
, i
, j
));
1234 else if (fmt
[i
] == 'e')
1235 r
|= swap_rtx_condition_1 (XEXP (pat
, i
));
1243 swap_rtx_condition (insn
)
1246 rtx pat
= PATTERN (insn
);
1248 /* We're looking for a single set to cc0 or an HImode temporary. */
1250 if (GET_CODE (pat
) == SET
1251 && GET_CODE (SET_DEST (pat
)) == REG
1252 && REGNO (SET_DEST (pat
)) == FLAGS_REG
)
1254 insn
= next_flags_user (insn
);
1255 if (insn
== NULL_RTX
)
1257 pat
= PATTERN (insn
);
1260 /* See if this is, or ends in, a fnstsw, aka unspec 9. If so, we're
1261 not doing anything with the cc value right now. We may be able to
1262 search for one though. */
1264 if (GET_CODE (pat
) == SET
1265 && GET_CODE (SET_SRC (pat
)) == UNSPEC
1266 && XINT (SET_SRC (pat
), 1) == UNSPEC_FNSTSW
)
1268 rtx dest
= SET_DEST (pat
);
1270 /* Search forward looking for the first use of this value.
1271 Stop at block boundaries. */
1272 while (insn
!= current_block
->end
)
1274 insn
= NEXT_INSN (insn
);
1275 if (INSN_P (insn
) && reg_mentioned_p (dest
, insn
))
1277 if (GET_CODE (insn
) == CALL_INSN
)
1281 /* So we've found the insn using this value. If it is anything
1282 other than sahf, aka unspec 10, or the value does not die
1283 (meaning we'd have to search further), then we must give up. */
1284 pat
= PATTERN (insn
);
1285 if (GET_CODE (pat
) != SET
1286 || GET_CODE (SET_SRC (pat
)) != UNSPEC
1287 || XINT (SET_SRC (pat
), 1) != UNSPEC_SAHF
1288 || ! dead_or_set_p (insn
, dest
))
1291 /* Now we are prepared to handle this as a normal cc0 setter. */
1292 insn
= next_flags_user (insn
);
1293 if (insn
== NULL_RTX
)
1295 pat
= PATTERN (insn
);
1298 if (swap_rtx_condition_1 (pat
))
1301 INSN_CODE (insn
) = -1;
1302 if (recog_memoized (insn
) == -1)
1304 /* In case the flags don't die here, recurse to try fix
1305 following user too. */
1306 else if (! dead_or_set_p (insn
, ix86_flags_rtx
))
1308 insn
= next_flags_user (insn
);
1309 if (!insn
|| !swap_rtx_condition (insn
))
1314 swap_rtx_condition_1 (pat
);
1322 /* Handle a comparison. Special care needs to be taken to avoid
1323 causing comparisons that a 387 cannot do correctly, such as EQ.
1325 Also, a pop insn may need to be emitted. The 387 does have an
1326 `fcompp' insn that can pop two regs, but it is sometimes too expensive
1327 to do this - a `fcomp' followed by a `fstpl %st(0)' may be easier to
1331 compare_for_stack_reg (insn
, regstack
, pat_src
)
1337 rtx src1_note
, src2_note
;
1340 src1
= get_true_reg (&XEXP (pat_src
, 0));
1341 src2
= get_true_reg (&XEXP (pat_src
, 1));
1342 flags_user
= next_flags_user (insn
);
1344 /* ??? If fxch turns out to be cheaper than fstp, give priority to
1345 registers that die in this insn - move those to stack top first. */
1346 if ((! STACK_REG_P (*src1
)
1347 || (STACK_REG_P (*src2
)
1348 && get_hard_regnum (regstack
, *src2
) == FIRST_STACK_REG
))
1349 && swap_rtx_condition (insn
))
1352 temp
= XEXP (pat_src
, 0);
1353 XEXP (pat_src
, 0) = XEXP (pat_src
, 1);
1354 XEXP (pat_src
, 1) = temp
;
1356 src1
= get_true_reg (&XEXP (pat_src
, 0));
1357 src2
= get_true_reg (&XEXP (pat_src
, 1));
1359 INSN_CODE (insn
) = -1;
1362 /* We will fix any death note later. */
1364 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1366 if (STACK_REG_P (*src2
))
1367 src2_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src2
));
1369 src2_note
= NULL_RTX
;
1371 emit_swap_insn (insn
, regstack
, *src1
);
1373 replace_reg (src1
, FIRST_STACK_REG
);
1375 if (STACK_REG_P (*src2
))
1376 replace_reg (src2
, get_hard_regnum (regstack
, *src2
));
1380 pop_stack (regstack
, REGNO (XEXP (src1_note
, 0)));
1381 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1384 /* If the second operand dies, handle that. But if the operands are
1385 the same stack register, don't bother, because only one death is
1386 needed, and it was just handled. */
1389 && ! (STACK_REG_P (*src1
) && STACK_REG_P (*src2
)
1390 && REGNO (*src1
) == REGNO (*src2
)))
1392 /* As a special case, two regs may die in this insn if src2 is
1393 next to top of stack and the top of stack also dies. Since
1394 we have already popped src1, "next to top of stack" is really
1395 at top (FIRST_STACK_REG) now. */
1397 if (get_hard_regnum (regstack
, XEXP (src2_note
, 0)) == FIRST_STACK_REG
1400 pop_stack (regstack
, REGNO (XEXP (src2_note
, 0)));
1401 replace_reg (&XEXP (src2_note
, 0), FIRST_STACK_REG
+ 1);
1405 /* The 386 can only represent death of the first operand in
1406 the case handled above. In all other cases, emit a separate
1407 pop and remove the death note from here. */
1409 /* link_cc0_insns (insn); */
1411 remove_regno_note (insn
, REG_DEAD
, REGNO (XEXP (src2_note
, 0)));
1413 emit_pop_insn (insn
, regstack
, XEXP (src2_note
, 0),
1419 /* Substitute new registers in PAT, which is part of INSN. REGSTACK
1420 is the current register layout. */
1423 subst_stack_regs_pat (insn
, regstack
, pat
)
1430 switch (GET_CODE (pat
))
1433 /* Deaths in USE insns can happen in non optimizing compilation.
1434 Handle them by popping the dying register. */
1435 src
= get_true_reg (&XEXP (pat
, 0));
1436 if (STACK_REG_P (*src
)
1437 && find_regno_note (insn
, REG_DEAD
, REGNO (*src
)))
1439 emit_pop_insn (insn
, regstack
, *src
, EMIT_AFTER
);
1442 /* ??? Uninitialized USE should not happen. */
1443 else if (get_hard_regnum (regstack
, *src
) == -1)
1451 dest
= get_true_reg (&XEXP (pat
, 0));
1452 if (STACK_REG_P (*dest
))
1454 note
= find_reg_note (insn
, REG_DEAD
, *dest
);
1456 if (pat
!= PATTERN (insn
))
1458 /* The fix_truncdi_1 pattern wants to be able to allocate
1459 it's own scratch register. It does this by clobbering
1460 an fp reg so that it is assured of an empty reg-stack
1461 register. If the register is live, kill it now.
1462 Remove the DEAD/UNUSED note so we don't try to kill it
1466 emit_pop_insn (insn
, regstack
, *dest
, EMIT_BEFORE
);
1469 note
= find_reg_note (insn
, REG_UNUSED
, *dest
);
1473 remove_note (insn
, note
);
1474 replace_reg (dest
, LAST_STACK_REG
);
1478 /* A top-level clobber with no REG_DEAD, and no hard-regnum
1479 indicates an uninitialized value. Because reload removed
1480 all other clobbers, this must be due to a function
1481 returning without a value. Load up a NaN. */
1484 && get_hard_regnum (regstack
, *dest
) == -1)
1486 pat
= gen_rtx_SET (VOIDmode
,
1487 FP_MODE_REG (REGNO (*dest
), SFmode
),
1489 PATTERN (insn
) = pat
;
1490 move_for_stack_reg (insn
, regstack
, pat
);
1492 if (! note
&& COMPLEX_MODE_P (GET_MODE (*dest
))
1493 && get_hard_regnum (regstack
, FP_MODE_REG (REGNO (*dest
), DFmode
)) == -1)
1495 pat
= gen_rtx_SET (VOIDmode
,
1496 FP_MODE_REG (REGNO (*dest
) + 1, SFmode
),
1498 PATTERN (insn
) = pat
;
1499 move_for_stack_reg (insn
, regstack
, pat
);
1508 rtx
*src1
= (rtx
*) 0, *src2
;
1509 rtx src1_note
, src2_note
;
1512 dest
= get_true_reg (&SET_DEST (pat
));
1513 src
= get_true_reg (&SET_SRC (pat
));
1514 pat_src
= SET_SRC (pat
);
1516 /* See if this is a `movM' pattern, and handle elsewhere if so. */
1517 if (STACK_REG_P (*src
)
1518 || (STACK_REG_P (*dest
)
1519 && (GET_CODE (*src
) == REG
|| GET_CODE (*src
) == MEM
1520 || GET_CODE (*src
) == CONST_DOUBLE
)))
1522 move_for_stack_reg (insn
, regstack
, pat
);
1526 switch (GET_CODE (pat_src
))
1529 compare_for_stack_reg (insn
, regstack
, pat_src
);
1535 for (count
= HARD_REGNO_NREGS (REGNO (*dest
), GET_MODE (*dest
));
1538 regstack
->reg
[++regstack
->top
] = REGNO (*dest
) + count
;
1539 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
) + count
);
1542 replace_reg (dest
, FIRST_STACK_REG
);
1546 /* This is a `tstM2' case. */
1547 if (*dest
!= cc0_rtx
)
1553 case FLOAT_TRUNCATE
:
1557 /* These insns only operate on the top of the stack. DEST might
1558 be cc0_rtx if we're processing a tstM pattern. Also, it's
1559 possible that the tstM case results in a REG_DEAD note on the
1563 src1
= get_true_reg (&XEXP (pat_src
, 0));
1565 emit_swap_insn (insn
, regstack
, *src1
);
1567 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1569 if (STACK_REG_P (*dest
))
1570 replace_reg (dest
, FIRST_STACK_REG
);
1574 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1576 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (*src1
));
1579 replace_reg (src1
, FIRST_STACK_REG
);
1584 /* On i386, reversed forms of subM3 and divM3 exist for
1585 MODE_FLOAT, so the same code that works for addM3 and mulM3
1589 /* These insns can accept the top of stack as a destination
1590 from a stack reg or mem, or can use the top of stack as a
1591 source and some other stack register (possibly top of stack)
1592 as a destination. */
1594 src1
= get_true_reg (&XEXP (pat_src
, 0));
1595 src2
= get_true_reg (&XEXP (pat_src
, 1));
1597 /* We will fix any death note later. */
1599 if (STACK_REG_P (*src1
))
1600 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1602 src1_note
= NULL_RTX
;
1603 if (STACK_REG_P (*src2
))
1604 src2_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src2
));
1606 src2_note
= NULL_RTX
;
1608 /* If either operand is not a stack register, then the dest
1609 must be top of stack. */
1611 if (! STACK_REG_P (*src1
) || ! STACK_REG_P (*src2
))
1612 emit_swap_insn (insn
, regstack
, *dest
);
1615 /* Both operands are REG. If neither operand is already
1616 at the top of stack, choose to make the one that is the dest
1617 the new top of stack. */
1619 int src1_hard_regnum
, src2_hard_regnum
;
1621 src1_hard_regnum
= get_hard_regnum (regstack
, *src1
);
1622 src2_hard_regnum
= get_hard_regnum (regstack
, *src2
);
1623 if (src1_hard_regnum
== -1 || src2_hard_regnum
== -1)
1626 if (src1_hard_regnum
!= FIRST_STACK_REG
1627 && src2_hard_regnum
!= FIRST_STACK_REG
)
1628 emit_swap_insn (insn
, regstack
, *dest
);
1631 if (STACK_REG_P (*src1
))
1632 replace_reg (src1
, get_hard_regnum (regstack
, *src1
));
1633 if (STACK_REG_P (*src2
))
1634 replace_reg (src2
, get_hard_regnum (regstack
, *src2
));
1638 rtx src1_reg
= XEXP (src1_note
, 0);
1640 /* If the register that dies is at the top of stack, then
1641 the destination is somewhere else - merely substitute it.
1642 But if the reg that dies is not at top of stack, then
1643 move the top of stack to the dead reg, as though we had
1644 done the insn and then a store-with-pop. */
1646 if (REGNO (src1_reg
) == regstack
->reg
[regstack
->top
])
1648 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1649 replace_reg (dest
, get_hard_regnum (regstack
, *dest
));
1653 int regno
= get_hard_regnum (regstack
, src1_reg
);
1655 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1656 replace_reg (dest
, regno
);
1658 regstack
->reg
[regstack
->top
- (regno
- FIRST_STACK_REG
)]
1659 = regstack
->reg
[regstack
->top
];
1662 CLEAR_HARD_REG_BIT (regstack
->reg_set
,
1663 REGNO (XEXP (src1_note
, 0)));
1664 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1669 rtx src2_reg
= XEXP (src2_note
, 0);
1670 if (REGNO (src2_reg
) == regstack
->reg
[regstack
->top
])
1672 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1673 replace_reg (dest
, get_hard_regnum (regstack
, *dest
));
1677 int regno
= get_hard_regnum (regstack
, src2_reg
);
1679 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1680 replace_reg (dest
, regno
);
1682 regstack
->reg
[regstack
->top
- (regno
- FIRST_STACK_REG
)]
1683 = regstack
->reg
[regstack
->top
];
1686 CLEAR_HARD_REG_BIT (regstack
->reg_set
,
1687 REGNO (XEXP (src2_note
, 0)));
1688 replace_reg (&XEXP (src2_note
, 0), FIRST_STACK_REG
);
1693 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1694 replace_reg (dest
, get_hard_regnum (regstack
, *dest
));
1697 /* Keep operand 1 matching with destination. */
1698 if (GET_RTX_CLASS (GET_CODE (pat_src
)) == 'c'
1699 && REG_P (*src1
) && REG_P (*src2
)
1700 && REGNO (*src1
) != REGNO (*dest
))
1702 int tmp
= REGNO (*src1
);
1703 replace_reg (src1
, REGNO (*src2
));
1704 replace_reg (src2
, tmp
);
1709 switch (XINT (pat_src
, 1))
1713 /* These insns only operate on the top of the stack. */
1715 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1717 emit_swap_insn (insn
, regstack
, *src1
);
1719 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1721 if (STACK_REG_P (*dest
))
1722 replace_reg (dest
, FIRST_STACK_REG
);
1726 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1728 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (*src1
));
1731 replace_reg (src1
, FIRST_STACK_REG
);
1735 /* These insns operate on the top two stack slots. */
1737 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1738 src2
= get_true_reg (&XVECEXP (pat_src
, 0, 1));
1740 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1741 src2_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src2
));
1744 struct stack_def temp_stack
;
1745 int regno
, j
, k
, temp
;
1747 temp_stack
= *regstack
;
1749 /* Place operand 1 at the top of stack. */
1750 regno
= get_hard_regnum (&temp_stack
, *src1
);
1753 if (regno
!= FIRST_STACK_REG
)
1755 k
= temp_stack
.top
- (regno
- FIRST_STACK_REG
);
1758 temp
= temp_stack
.reg
[k
];
1759 temp_stack
.reg
[k
] = temp_stack
.reg
[j
];
1760 temp_stack
.reg
[j
] = temp
;
1763 /* Place operand 2 next on the stack. */
1764 regno
= get_hard_regnum (&temp_stack
, *src2
);
1767 if (regno
!= FIRST_STACK_REG
+ 1)
1769 k
= temp_stack
.top
- (regno
- FIRST_STACK_REG
);
1770 j
= temp_stack
.top
- 1;
1772 temp
= temp_stack
.reg
[k
];
1773 temp_stack
.reg
[k
] = temp_stack
.reg
[j
];
1774 temp_stack
.reg
[j
] = temp
;
1777 change_stack (insn
, regstack
, &temp_stack
, EMIT_BEFORE
);
1780 replace_reg (src1
, FIRST_STACK_REG
);
1781 replace_reg (src2
, FIRST_STACK_REG
+ 1);
1784 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1786 replace_reg (&XEXP (src2_note
, 0), FIRST_STACK_REG
+ 1);
1788 /* Pop both input operands from the stack. */
1789 CLEAR_HARD_REG_BIT (regstack
->reg_set
,
1790 regstack
->reg
[regstack
->top
]);
1791 CLEAR_HARD_REG_BIT (regstack
->reg_set
,
1792 regstack
->reg
[regstack
->top
- 1]);
1795 /* Push the result back onto the stack. */
1796 regstack
->reg
[++regstack
->top
] = REGNO (*dest
);
1797 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1798 replace_reg (dest
, FIRST_STACK_REG
);
1802 /* (unspec [(unspec [(compare)] UNSPEC_FNSTSW)] UNSPEC_SAHF)
1803 The combination matches the PPRO fcomi instruction. */
1805 pat_src
= XVECEXP (pat_src
, 0, 0);
1806 if (GET_CODE (pat_src
) != UNSPEC
1807 || XINT (pat_src
, 1) != UNSPEC_FNSTSW
)
1812 /* Combined fcomp+fnstsw generated for doing well with
1813 CSE. When optimizing this would have been broken
1816 pat_src
= XVECEXP (pat_src
, 0, 0);
1817 if (GET_CODE (pat_src
) != COMPARE
)
1820 compare_for_stack_reg (insn
, regstack
, pat_src
);
1829 /* This insn requires the top of stack to be the destination. */
1831 src1
= get_true_reg (&XEXP (pat_src
, 1));
1832 src2
= get_true_reg (&XEXP (pat_src
, 2));
1834 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1835 src2_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src2
));
1837 /* If the comparison operator is an FP comparison operator,
1838 it is handled correctly by compare_for_stack_reg () who
1839 will move the destination to the top of stack. But if the
1840 comparison operator is not an FP comparison operator, we
1841 have to handle it here. */
1842 if (get_hard_regnum (regstack
, *dest
) >= FIRST_STACK_REG
1843 && REGNO (*dest
) != regstack
->reg
[regstack
->top
])
1845 /* In case one of operands is the top of stack and the operands
1846 dies, it is safe to make it the destination operand by
1847 reversing the direction of cmove and avoid fxch. */
1848 if ((REGNO (*src1
) == regstack
->reg
[regstack
->top
]
1850 || (REGNO (*src2
) == regstack
->reg
[regstack
->top
]
1853 int idx1
= (get_hard_regnum (regstack
, *src1
)
1855 int idx2
= (get_hard_regnum (regstack
, *src2
)
1858 /* Make reg-stack believe that the operands are already
1859 swapped on the stack */
1860 regstack
->reg
[regstack
->top
- idx1
] = REGNO (*src2
);
1861 regstack
->reg
[regstack
->top
- idx2
] = REGNO (*src1
);
1863 /* Reverse condition to compensate the operand swap.
1864 i386 do have comparison always reversible. */
1865 PUT_CODE (XEXP (pat_src
, 0),
1866 reversed_comparison_code (XEXP (pat_src
, 0), insn
));
1869 emit_swap_insn (insn
, regstack
, *dest
);
1877 src_note
[1] = src1_note
;
1878 src_note
[2] = src2_note
;
1880 if (STACK_REG_P (*src1
))
1881 replace_reg (src1
, get_hard_regnum (regstack
, *src1
));
1882 if (STACK_REG_P (*src2
))
1883 replace_reg (src2
, get_hard_regnum (regstack
, *src2
));
1885 for (i
= 1; i
<= 2; i
++)
1888 int regno
= REGNO (XEXP (src_note
[i
], 0));
1890 /* If the register that dies is not at the top of
1891 stack, then move the top of stack to the dead reg */
1892 if (regno
!= regstack
->reg
[regstack
->top
])
1894 remove_regno_note (insn
, REG_DEAD
, regno
);
1895 emit_pop_insn (insn
, regstack
, XEXP (src_note
[i
], 0),
1899 /* Top of stack never dies, as it is the
1905 /* Make dest the top of stack. Add dest to regstack if
1907 if (get_hard_regnum (regstack
, *dest
) < FIRST_STACK_REG
)
1908 regstack
->reg
[++regstack
->top
] = REGNO (*dest
);
1909 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1910 replace_reg (dest
, FIRST_STACK_REG
);
1924 /* Substitute hard regnums for any stack regs in INSN, which has
1925 N_INPUTS inputs and N_OUTPUTS outputs. REGSTACK is the stack info
1926 before the insn, and is updated with changes made here.
1928 There are several requirements and assumptions about the use of
1929 stack-like regs in asm statements. These rules are enforced by
1930 record_asm_stack_regs; see comments there for details. Any
1931 asm_operands left in the RTL at this point may be assume to meet the
1932 requirements, since record_asm_stack_regs removes any problem asm. */
1935 subst_asm_stack_regs (insn
, regstack
)
1939 rtx body
= PATTERN (insn
);
1942 rtx
*note_reg
; /* Array of note contents */
1943 rtx
**note_loc
; /* Address of REG field of each note */
1944 enum reg_note
*note_kind
; /* The type of each note */
1946 rtx
*clobber_reg
= 0;
1947 rtx
**clobber_loc
= 0;
1949 struct stack_def temp_stack
;
1954 int n_inputs
, n_outputs
;
1956 if (! check_asm_stack_operands (insn
))
1959 /* Find out what the constraints required. If no constraint
1960 alternative matches, that is a compiler bug: we should have caught
1961 such an insn in check_asm_stack_operands. */
1962 extract_insn (insn
);
1963 constrain_operands (1);
1964 alt
= which_alternative
;
1966 preprocess_constraints ();
1968 n_inputs
= get_asm_operand_n_inputs (body
);
1969 n_outputs
= recog_data
.n_operands
- n_inputs
;
1974 /* Strip SUBREGs here to make the following code simpler. */
1975 for (i
= 0; i
< recog_data
.n_operands
; i
++)
1976 if (GET_CODE (recog_data
.operand
[i
]) == SUBREG
1977 && GET_CODE (SUBREG_REG (recog_data
.operand
[i
])) == REG
)
1979 recog_data
.operand_loc
[i
] = & SUBREG_REG (recog_data
.operand
[i
]);
1980 recog_data
.operand
[i
] = SUBREG_REG (recog_data
.operand
[i
]);
1983 /* Set up NOTE_REG, NOTE_LOC and NOTE_KIND. */
1985 for (i
= 0, note
= REG_NOTES (insn
); note
; note
= XEXP (note
, 1))
1988 note_reg
= (rtx
*) alloca (i
* sizeof (rtx
));
1989 note_loc
= (rtx
**) alloca (i
* sizeof (rtx
*));
1990 note_kind
= (enum reg_note
*) alloca (i
* sizeof (enum reg_note
));
1993 for (note
= REG_NOTES (insn
); note
; note
= XEXP (note
, 1))
1995 rtx reg
= XEXP (note
, 0);
1996 rtx
*loc
= & XEXP (note
, 0);
1998 if (GET_CODE (reg
) == SUBREG
&& GET_CODE (SUBREG_REG (reg
)) == REG
)
2000 loc
= & SUBREG_REG (reg
);
2001 reg
= SUBREG_REG (reg
);
2004 if (STACK_REG_P (reg
)
2005 && (REG_NOTE_KIND (note
) == REG_DEAD
2006 || REG_NOTE_KIND (note
) == REG_UNUSED
))
2008 note_reg
[n_notes
] = reg
;
2009 note_loc
[n_notes
] = loc
;
2010 note_kind
[n_notes
] = REG_NOTE_KIND (note
);
2015 /* Set up CLOBBER_REG and CLOBBER_LOC. */
2019 if (GET_CODE (body
) == PARALLEL
)
2021 clobber_reg
= (rtx
*) alloca (XVECLEN (body
, 0) * sizeof (rtx
));
2022 clobber_loc
= (rtx
**) alloca (XVECLEN (body
, 0) * sizeof (rtx
*));
2024 for (i
= 0; i
< XVECLEN (body
, 0); i
++)
2025 if (GET_CODE (XVECEXP (body
, 0, i
)) == CLOBBER
)
2027 rtx clobber
= XVECEXP (body
, 0, i
);
2028 rtx reg
= XEXP (clobber
, 0);
2029 rtx
*loc
= & XEXP (clobber
, 0);
2031 if (GET_CODE (reg
) == SUBREG
&& GET_CODE (SUBREG_REG (reg
)) == REG
)
2033 loc
= & SUBREG_REG (reg
);
2034 reg
= SUBREG_REG (reg
);
2037 if (STACK_REG_P (reg
))
2039 clobber_reg
[n_clobbers
] = reg
;
2040 clobber_loc
[n_clobbers
] = loc
;
2046 temp_stack
= *regstack
;
2048 /* Put the input regs into the desired place in TEMP_STACK. */
2050 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
2051 if (STACK_REG_P (recog_data
.operand
[i
])
2052 && reg_class_subset_p (recog_op_alt
[i
][alt
].class,
2054 && recog_op_alt
[i
][alt
].class != FLOAT_REGS
)
2056 /* If an operand needs to be in a particular reg in
2057 FLOAT_REGS, the constraint was either 't' or 'u'. Since
2058 these constraints are for single register classes, and
2059 reload guaranteed that operand[i] is already in that class,
2060 we can just use REGNO (recog_data.operand[i]) to know which
2061 actual reg this operand needs to be in. */
2063 int regno
= get_hard_regnum (&temp_stack
, recog_data
.operand
[i
]);
2068 if ((unsigned int) regno
!= REGNO (recog_data
.operand
[i
]))
2070 /* recog_data.operand[i] is not in the right place. Find
2071 it and swap it with whatever is already in I's place.
2072 K is where recog_data.operand[i] is now. J is where it
2076 k
= temp_stack
.top
- (regno
- FIRST_STACK_REG
);
2078 - (REGNO (recog_data
.operand
[i
]) - FIRST_STACK_REG
));
2080 temp
= temp_stack
.reg
[k
];
2081 temp_stack
.reg
[k
] = temp_stack
.reg
[j
];
2082 temp_stack
.reg
[j
] = temp
;
2086 /* Emit insns before INSN to make sure the reg-stack is in the right
2089 change_stack (insn
, regstack
, &temp_stack
, EMIT_BEFORE
);
2091 /* Make the needed input register substitutions. Do death notes and
2092 clobbers too, because these are for inputs, not outputs. */
2094 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
2095 if (STACK_REG_P (recog_data
.operand
[i
]))
2097 int regnum
= get_hard_regnum (regstack
, recog_data
.operand
[i
]);
2102 replace_reg (recog_data
.operand_loc
[i
], regnum
);
2105 for (i
= 0; i
< n_notes
; i
++)
2106 if (note_kind
[i
] == REG_DEAD
)
2108 int regnum
= get_hard_regnum (regstack
, note_reg
[i
]);
2113 replace_reg (note_loc
[i
], regnum
);
2116 for (i
= 0; i
< n_clobbers
; i
++)
2118 /* It's OK for a CLOBBER to reference a reg that is not live.
2119 Don't try to replace it in that case. */
2120 int regnum
= get_hard_regnum (regstack
, clobber_reg
[i
]);
2124 /* Sigh - clobbers always have QImode. But replace_reg knows
2125 that these regs can't be MODE_INT and will abort. Just put
2126 the right reg there without calling replace_reg. */
2128 *clobber_loc
[i
] = FP_MODE_REG (regnum
, DFmode
);
2132 /* Now remove from REGSTACK any inputs that the asm implicitly popped. */
2134 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
2135 if (STACK_REG_P (recog_data
.operand
[i
]))
2137 /* An input reg is implicitly popped if it is tied to an
2138 output, or if there is a CLOBBER for it. */
2141 for (j
= 0; j
< n_clobbers
; j
++)
2142 if (operands_match_p (clobber_reg
[j
], recog_data
.operand
[i
]))
2145 if (j
< n_clobbers
|| recog_op_alt
[i
][alt
].matches
>= 0)
2147 /* recog_data.operand[i] might not be at the top of stack.
2148 But that's OK, because all we need to do is pop the
2149 right number of regs off of the top of the reg-stack.
2150 record_asm_stack_regs guaranteed that all implicitly
2151 popped regs were grouped at the top of the reg-stack. */
2153 CLEAR_HARD_REG_BIT (regstack
->reg_set
,
2154 regstack
->reg
[regstack
->top
]);
2159 /* Now add to REGSTACK any outputs that the asm implicitly pushed.
2160 Note that there isn't any need to substitute register numbers.
2161 ??? Explain why this is true. */
2163 for (i
= LAST_STACK_REG
; i
>= FIRST_STACK_REG
; i
--)
2165 /* See if there is an output for this hard reg. */
2168 for (j
= 0; j
< n_outputs
; j
++)
2169 if (STACK_REG_P (recog_data
.operand
[j
])
2170 && REGNO (recog_data
.operand
[j
]) == (unsigned) i
)
2172 regstack
->reg
[++regstack
->top
] = i
;
2173 SET_HARD_REG_BIT (regstack
->reg_set
, i
);
2178 /* Now emit a pop insn for any REG_UNUSED output, or any REG_DEAD
2179 input that the asm didn't implicitly pop. If the asm didn't
2180 implicitly pop an input reg, that reg will still be live.
2182 Note that we can't use find_regno_note here: the register numbers
2183 in the death notes have already been substituted. */
2185 for (i
= 0; i
< n_outputs
; i
++)
2186 if (STACK_REG_P (recog_data
.operand
[i
]))
2190 for (j
= 0; j
< n_notes
; j
++)
2191 if (REGNO (recog_data
.operand
[i
]) == REGNO (note_reg
[j
])
2192 && note_kind
[j
] == REG_UNUSED
)
2194 insn
= emit_pop_insn (insn
, regstack
, recog_data
.operand
[i
],
2200 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
2201 if (STACK_REG_P (recog_data
.operand
[i
]))
2205 for (j
= 0; j
< n_notes
; j
++)
2206 if (REGNO (recog_data
.operand
[i
]) == REGNO (note_reg
[j
])
2207 && note_kind
[j
] == REG_DEAD
2208 && TEST_HARD_REG_BIT (regstack
->reg_set
,
2209 REGNO (recog_data
.operand
[i
])))
2211 insn
= emit_pop_insn (insn
, regstack
, recog_data
.operand
[i
],
2218 /* Substitute stack hard reg numbers for stack virtual registers in
2219 INSN. Non-stack register numbers are not changed. REGSTACK is the
2220 current stack content. Insns may be emitted as needed to arrange the
2221 stack for the 387 based on the contents of the insn. */
2224 subst_stack_regs (insn
, regstack
)
2228 rtx
*note_link
, note
;
2231 if (GET_CODE (insn
) == CALL_INSN
)
2233 int top
= regstack
->top
;
2235 /* If there are any floating point parameters to be passed in
2236 registers for this call, make sure they are in the right
2241 straighten_stack (PREV_INSN (insn
), regstack
);
2243 /* Now mark the arguments as dead after the call. */
2245 while (regstack
->top
>= 0)
2247 CLEAR_HARD_REG_BIT (regstack
->reg_set
, FIRST_STACK_REG
+ regstack
->top
);
2253 /* Do the actual substitution if any stack regs are mentioned.
2254 Since we only record whether entire insn mentions stack regs, and
2255 subst_stack_regs_pat only works for patterns that contain stack regs,
2256 we must check each pattern in a parallel here. A call_value_pop could
2259 if (stack_regs_mentioned (insn
))
2261 int n_operands
= asm_noperands (PATTERN (insn
));
2262 if (n_operands
>= 0)
2264 /* This insn is an `asm' with operands. Decode the operands,
2265 decide how many are inputs, and do register substitution.
2266 Any REG_UNUSED notes will be handled by subst_asm_stack_regs. */
2268 subst_asm_stack_regs (insn
, regstack
);
2272 if (GET_CODE (PATTERN (insn
)) == PARALLEL
)
2273 for (i
= 0; i
< XVECLEN (PATTERN (insn
), 0); i
++)
2275 if (stack_regs_mentioned_p (XVECEXP (PATTERN (insn
), 0, i
)))
2276 subst_stack_regs_pat (insn
, regstack
,
2277 XVECEXP (PATTERN (insn
), 0, i
));
2280 subst_stack_regs_pat (insn
, regstack
, PATTERN (insn
));
2283 /* subst_stack_regs_pat may have deleted a no-op insn. If so, any
2284 REG_UNUSED will already have been dealt with, so just return. */
2286 if (GET_CODE (insn
) == NOTE
|| INSN_DELETED_P (insn
))
2289 /* If there is a REG_UNUSED note on a stack register on this insn,
2290 the indicated reg must be popped. The REG_UNUSED note is removed,
2291 since the form of the newly emitted pop insn references the reg,
2292 making it no longer `unset'. */
2294 note_link
= ®_NOTES (insn
);
2295 for (note
= *note_link
; note
; note
= XEXP (note
, 1))
2296 if (REG_NOTE_KIND (note
) == REG_UNUSED
&& STACK_REG_P (XEXP (note
, 0)))
2298 *note_link
= XEXP (note
, 1);
2299 insn
= emit_pop_insn (insn
, regstack
, XEXP (note
, 0), EMIT_AFTER
);
2302 note_link
= &XEXP (note
, 1);
2305 /* Change the organization of the stack so that it fits a new basic
2306 block. Some registers might have to be popped, but there can never be
2307 a register live in the new block that is not now live.
2309 Insert any needed insns before or after INSN, as indicated by
2310 WHERE. OLD is the original stack layout, and NEW is the desired
2311 form. OLD is updated to reflect the code emitted, ie, it will be
2312 the same as NEW upon return.
2314 This function will not preserve block_end[]. But that information
2315 is no longer needed once this has executed. */
2318 change_stack (insn
, old
, new, where
)
2322 enum emit_where where
;
2327 /* We will be inserting new insns "backwards". If we are to insert
2328 after INSN, find the next insn, and insert before it. */
2330 if (where
== EMIT_AFTER
)
2332 if (current_block
&& current_block
->end
== insn
)
2334 insn
= NEXT_INSN (insn
);
2337 /* Pop any registers that are not needed in the new block. */
2339 for (reg
= old
->top
; reg
>= 0; reg
--)
2340 if (! TEST_HARD_REG_BIT (new->reg_set
, old
->reg
[reg
]))
2341 emit_pop_insn (insn
, old
, FP_MODE_REG (old
->reg
[reg
], DFmode
),
2346 /* If the new block has never been processed, then it can inherit
2347 the old stack order. */
2349 new->top
= old
->top
;
2350 memcpy (new->reg
, old
->reg
, sizeof (new->reg
));
2354 /* This block has been entered before, and we must match the
2355 previously selected stack order. */
2357 /* By now, the only difference should be the order of the stack,
2358 not their depth or liveliness. */
2360 GO_IF_HARD_REG_EQUAL (old
->reg_set
, new->reg_set
, win
);
2363 if (old
->top
!= new->top
)
2366 /* If the stack is not empty (new->top != -1), loop here emitting
2367 swaps until the stack is correct.
2369 The worst case number of swaps emitted is N + 2, where N is the
2370 depth of the stack. In some cases, the reg at the top of
2371 stack may be correct, but swapped anyway in order to fix
2372 other regs. But since we never swap any other reg away from
2373 its correct slot, this algorithm will converge. */
2378 /* Swap the reg at top of stack into the position it is
2379 supposed to be in, until the correct top of stack appears. */
2381 while (old
->reg
[old
->top
] != new->reg
[new->top
])
2383 for (reg
= new->top
; reg
>= 0; reg
--)
2384 if (new->reg
[reg
] == old
->reg
[old
->top
])
2390 emit_swap_insn (insn
, old
,
2391 FP_MODE_REG (old
->reg
[reg
], DFmode
));
2394 /* See if any regs remain incorrect. If so, bring an
2395 incorrect reg to the top of stack, and let the while loop
2398 for (reg
= new->top
; reg
>= 0; reg
--)
2399 if (new->reg
[reg
] != old
->reg
[reg
])
2401 emit_swap_insn (insn
, old
,
2402 FP_MODE_REG (old
->reg
[reg
], DFmode
));
2407 /* At this point there must be no differences. */
2409 for (reg
= old
->top
; reg
>= 0; reg
--)
2410 if (old
->reg
[reg
] != new->reg
[reg
])
2415 current_block
->end
= PREV_INSN (insn
);
2418 /* Print stack configuration. */
2421 print_stack (file
, s
)
2429 fprintf (file
, "uninitialized\n");
2430 else if (s
->top
== -1)
2431 fprintf (file
, "empty\n");
2436 for (i
= 0; i
<= s
->top
; ++i
)
2437 fprintf (file
, "%d ", s
->reg
[i
]);
2438 fputs ("]\n", file
);
2442 /* This function was doing life analysis. We now let the regular live
2443 code do it's job, so we only need to check some extra invariants
2444 that reg-stack expects. Primary among these being that all registers
2445 are initialized before use.
2447 The function returns true when code was emitted to CFG edges and
2448 commit_edge_insertions needs to be called. */
2451 convert_regs_entry ()
2457 FOR_EACH_BB_REVERSE (block
)
2459 block_info bi
= BLOCK_INFO (block
);
2462 /* Set current register status at last instruction `uninitialized'. */
2463 bi
->stack_in
.top
= -2;
2465 /* Copy live_at_end and live_at_start into temporaries. */
2466 for (reg
= FIRST_STACK_REG
; reg
<= LAST_STACK_REG
; reg
++)
2468 if (REGNO_REG_SET_P (block
->global_live_at_end
, reg
))
2469 SET_HARD_REG_BIT (bi
->out_reg_set
, reg
);
2470 if (REGNO_REG_SET_P (block
->global_live_at_start
, reg
))
2471 SET_HARD_REG_BIT (bi
->stack_in
.reg_set
, reg
);
2475 /* Load something into each stack register live at function entry.
2476 Such live registers can be caused by uninitialized variables or
2477 functions not returning values on all paths. In order to keep
2478 the push/pop code happy, and to not scrog the register stack, we
2479 must put something in these registers. Use a QNaN.
2481 Note that we are inserting converted code here. This code is
2482 never seen by the convert_regs pass. */
2484 for (e
= ENTRY_BLOCK_PTR
->succ
; e
; e
= e
->succ_next
)
2486 basic_block block
= e
->dest
;
2487 block_info bi
= BLOCK_INFO (block
);
2490 for (reg
= LAST_STACK_REG
; reg
>= FIRST_STACK_REG
; --reg
)
2491 if (TEST_HARD_REG_BIT (bi
->stack_in
.reg_set
, reg
))
2495 bi
->stack_in
.reg
[++top
] = reg
;
2497 init
= gen_rtx_SET (VOIDmode
,
2498 FP_MODE_REG (FIRST_STACK_REG
, SFmode
),
2500 insert_insn_on_edge (init
, e
);
2504 bi
->stack_in
.top
= top
;
2510 /* Construct the desired stack for function exit. This will either
2511 be `empty', or the function return value at top-of-stack. */
2514 convert_regs_exit ()
2516 int value_reg_low
, value_reg_high
;
2520 retvalue
= stack_result (current_function_decl
);
2521 value_reg_low
= value_reg_high
= -1;
2524 value_reg_low
= REGNO (retvalue
);
2525 value_reg_high
= value_reg_low
2526 + HARD_REGNO_NREGS (value_reg_low
, GET_MODE (retvalue
)) - 1;
2529 output_stack
= &BLOCK_INFO (EXIT_BLOCK_PTR
)->stack_in
;
2530 if (value_reg_low
== -1)
2531 output_stack
->top
= -1;
2536 output_stack
->top
= value_reg_high
- value_reg_low
;
2537 for (reg
= value_reg_low
; reg
<= value_reg_high
; ++reg
)
2539 output_stack
->reg
[value_reg_high
- reg
] = reg
;
2540 SET_HARD_REG_BIT (output_stack
->reg_set
, reg
);
2545 /* Adjust the stack of this block on exit to match the stack of the
2546 target block, or copy stack info into the stack of the successor
2547 of the successor hasn't been processed yet. */
2549 compensate_edge (e
, file
)
2553 basic_block block
= e
->src
, target
= e
->dest
;
2554 block_info bi
= BLOCK_INFO (block
);
2555 struct stack_def regstack
, tmpstack
;
2556 stack target_stack
= &BLOCK_INFO (target
)->stack_in
;
2559 current_block
= block
;
2560 regstack
= bi
->stack_out
;
2562 fprintf (file
, "Edge %d->%d: ", block
->index
, target
->index
);
2564 if (target_stack
->top
== -2)
2566 /* The target block hasn't had a stack order selected.
2567 We need merely ensure that no pops are needed. */
2568 for (reg
= regstack
.top
; reg
>= 0; --reg
)
2569 if (!TEST_HARD_REG_BIT (target_stack
->reg_set
, regstack
.reg
[reg
]))
2575 fprintf (file
, "new block; copying stack position\n");
2577 /* change_stack kills values in regstack. */
2578 tmpstack
= regstack
;
2580 change_stack (block
->end
, &tmpstack
, target_stack
, EMIT_AFTER
);
2585 fprintf (file
, "new block; pops needed\n");
2589 if (target_stack
->top
== regstack
.top
)
2591 for (reg
= target_stack
->top
; reg
>= 0; --reg
)
2592 if (target_stack
->reg
[reg
] != regstack
.reg
[reg
])
2598 fprintf (file
, "no changes needed\n");
2605 fprintf (file
, "correcting stack to ");
2606 print_stack (file
, target_stack
);
2610 /* Care for non-call EH edges specially. The normal return path have
2611 values in registers. These will be popped en masse by the unwind
2613 if ((e
->flags
& (EDGE_EH
| EDGE_ABNORMAL_CALL
)) == EDGE_EH
)
2614 target_stack
->top
= -1;
2616 /* Other calls may appear to have values live in st(0), but the
2617 abnormal return path will not have actually loaded the values. */
2618 else if (e
->flags
& EDGE_ABNORMAL_CALL
)
2620 /* Assert that the lifetimes are as we expect -- one value
2621 live at st(0) on the end of the source block, and no
2622 values live at the beginning of the destination block. */
2625 CLEAR_HARD_REG_SET (tmp
);
2626 GO_IF_HARD_REG_EQUAL (target_stack
->reg_set
, tmp
, eh1
);
2630 /* We are sure that there is st(0) live, otherwise we won't compensate.
2631 For complex return values, we may have st(1) live as well. */
2632 SET_HARD_REG_BIT (tmp
, FIRST_STACK_REG
);
2633 if (TEST_HARD_REG_BIT (regstack
.reg_set
, FIRST_STACK_REG
+ 1))
2634 SET_HARD_REG_BIT (tmp
, FIRST_STACK_REG
+ 1);
2635 GO_IF_HARD_REG_EQUAL (regstack
.reg_set
, tmp
, eh2
);
2639 target_stack
->top
= -1;
2642 /* It is better to output directly to the end of the block
2643 instead of to the edge, because emit_swap can do minimal
2644 insn scheduling. We can do this when there is only one
2645 edge out, and it is not abnormal. */
2646 else if (block
->succ
->succ_next
== NULL
&& !(e
->flags
& EDGE_ABNORMAL
))
2648 /* change_stack kills values in regstack. */
2649 tmpstack
= regstack
;
2651 change_stack (block
->end
, &tmpstack
, target_stack
,
2652 (GET_CODE (block
->end
) == JUMP_INSN
2653 ? EMIT_BEFORE
: EMIT_AFTER
));
2659 /* We don't support abnormal edges. Global takes care to
2660 avoid any live register across them, so we should never
2661 have to insert instructions on such edges. */
2662 if (e
->flags
& EDGE_ABNORMAL
)
2665 current_block
= NULL
;
2668 /* ??? change_stack needs some point to emit insns after. */
2669 after
= emit_note (NULL
, NOTE_INSN_DELETED
);
2671 tmpstack
= regstack
;
2672 change_stack (after
, &tmpstack
, target_stack
, EMIT_BEFORE
);
2677 insert_insn_on_edge (seq
, e
);
2683 /* Convert stack register references in one block. */
2686 convert_regs_1 (file
, block
)
2690 struct stack_def regstack
;
2691 block_info bi
= BLOCK_INFO (block
);
2694 edge e
, beste
= NULL
;
2698 /* Find the edge we will copy stack from. It should be the most frequent
2699 one as it will get cheapest after compensation code is generated,
2700 if multiple such exists, take one with largest count, prefer critical
2701 one (as splitting critical edges is more expensive), or one with lowest
2702 index, to avoid random changes with different orders of the edges. */
2703 for (e
= block
->pred
; e
; e
= e
->pred_next
)
2705 if (e
->flags
& EDGE_DFS_BACK
)
2709 else if (EDGE_FREQUENCY (beste
) < EDGE_FREQUENCY (e
))
2711 else if (EDGE_FREQUENCY (beste
) > EDGE_FREQUENCY (e
))
2713 else if (beste
->count
< e
->count
)
2715 else if (beste
->count
> e
->count
)
2717 else if ((EDGE_CRITICAL_P (e
) != 0)
2718 != (EDGE_CRITICAL_P (beste
) != 0))
2720 if (EDGE_CRITICAL_P (e
))
2723 else if (e
->src
->index
< beste
->src
->index
)
2727 /* Entry block does have stack already initialized. */
2728 if (bi
->stack_in
.top
== -2)
2729 inserted
|= compensate_edge (beste
, file
);
2733 current_block
= block
;
2737 fprintf (file
, "\nBasic block %d\nInput stack: ", block
->index
);
2738 print_stack (file
, &bi
->stack_in
);
2741 /* Process all insns in this block. Keep track of NEXT so that we
2742 don't process insns emitted while substituting in INSN. */
2744 regstack
= bi
->stack_in
;
2748 next
= NEXT_INSN (insn
);
2750 /* Ensure we have not missed a block boundary. */
2753 if (insn
== block
->end
)
2756 /* Don't bother processing unless there is a stack reg
2757 mentioned or if it's a CALL_INSN. */
2758 if (stack_regs_mentioned (insn
)
2759 || GET_CODE (insn
) == CALL_INSN
)
2763 fprintf (file
, " insn %d input stack: ",
2765 print_stack (file
, ®stack
);
2767 subst_stack_regs (insn
, ®stack
);
2774 fprintf (file
, "Expected live registers [");
2775 for (reg
= FIRST_STACK_REG
; reg
<= LAST_STACK_REG
; ++reg
)
2776 if (TEST_HARD_REG_BIT (bi
->out_reg_set
, reg
))
2777 fprintf (file
, " %d", reg
);
2778 fprintf (file
, " ]\nOutput stack: ");
2779 print_stack (file
, ®stack
);
2783 if (GET_CODE (insn
) == JUMP_INSN
)
2784 insn
= PREV_INSN (insn
);
2786 /* If the function is declared to return a value, but it returns one
2787 in only some cases, some registers might come live here. Emit
2788 necessary moves for them. */
2790 for (reg
= FIRST_STACK_REG
; reg
<= LAST_STACK_REG
; ++reg
)
2792 if (TEST_HARD_REG_BIT (bi
->out_reg_set
, reg
)
2793 && ! TEST_HARD_REG_BIT (regstack
.reg_set
, reg
))
2799 fprintf (file
, "Emitting insn initializing reg %d\n",
2803 set
= gen_rtx_SET (VOIDmode
, FP_MODE_REG (reg
, SFmode
),
2805 insn
= emit_insn_after (set
, insn
);
2806 subst_stack_regs (insn
, ®stack
);
2810 /* Something failed if the stack lives don't match. */
2811 GO_IF_HARD_REG_EQUAL (regstack
.reg_set
, bi
->out_reg_set
, win
);
2814 bi
->stack_out
= regstack
;
2816 /* Compensate the back edges, as those wasn't visited yet. */
2817 for (e
= block
->succ
; e
; e
= e
->succ_next
)
2819 if (e
->flags
& EDGE_DFS_BACK
2820 || (e
->dest
== EXIT_BLOCK_PTR
))
2822 if (!BLOCK_INFO (e
->dest
)->done
2823 && e
->dest
!= block
)
2825 inserted
|= compensate_edge (e
, file
);
2828 for (e
= block
->pred
; e
; e
= e
->pred_next
)
2830 if (e
!= beste
&& !(e
->flags
& EDGE_DFS_BACK
)
2831 && e
->src
!= ENTRY_BLOCK_PTR
)
2833 if (!BLOCK_INFO (e
->src
)->done
)
2835 inserted
|= compensate_edge (e
, file
);
2842 /* Convert registers in all blocks reachable from BLOCK. */
2845 convert_regs_2 (file
, block
)
2849 basic_block
*stack
, *sp
;
2852 stack
= (basic_block
*) xmalloc (sizeof (*stack
) * n_basic_blocks
);
2863 inserted
|= convert_regs_1 (file
, block
);
2864 BLOCK_INFO (block
)->done
= 1;
2866 for (e
= block
->succ
; e
; e
= e
->succ_next
)
2867 if (! (e
->flags
& EDGE_DFS_BACK
))
2869 BLOCK_INFO (e
->dest
)->predecessors
--;
2870 if (!BLOCK_INFO (e
->dest
)->predecessors
)
2874 while (sp
!= stack
);
2879 /* Traverse all basic blocks in a function, converting the register
2880 references in each insn from the "flat" register file that gcc uses,
2881 to the stack-like registers the 387 uses. */
2891 /* Initialize uninitialized registers on function entry. */
2892 inserted
= convert_regs_entry ();
2894 /* Construct the desired stack for function exit. */
2895 convert_regs_exit ();
2896 BLOCK_INFO (EXIT_BLOCK_PTR
)->done
= 1;
2898 /* ??? Future: process inner loops first, and give them arbitrary
2899 initial stacks which emit_swap_insn can modify. This ought to
2900 prevent double fxch that aften appears at the head of a loop. */
2902 /* Process all blocks reachable from all entry points. */
2903 for (e
= ENTRY_BLOCK_PTR
->succ
; e
; e
= e
->succ_next
)
2904 inserted
|= convert_regs_2 (file
, e
->dest
);
2906 /* ??? Process all unreachable blocks. Though there's no excuse
2907 for keeping these even when not optimizing. */
2910 block_info bi
= BLOCK_INFO (b
);
2916 /* Create an arbitrary input stack. */
2917 bi
->stack_in
.top
= -1;
2918 for (reg
= LAST_STACK_REG
; reg
>= FIRST_STACK_REG
; --reg
)
2919 if (TEST_HARD_REG_BIT (bi
->stack_in
.reg_set
, reg
))
2920 bi
->stack_in
.reg
[++bi
->stack_in
.top
] = reg
;
2922 inserted
|= convert_regs_2 (file
, b
);
2925 clear_aux_for_blocks ();
2927 fixup_abnormal_edges ();
2929 commit_edge_insertions ();
2936 #endif /* STACK_REGS */
2938 #include "gt-reg-stack.h"