1 /* Register to Stack convert for GNU compiler.
2 Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001 Free Software Foundation, Inc.
5 This file is part of GNU CC.
7 GNU CC is free software; you can redistribute it and/or modify
8 it 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 GNU CC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GNU CC; see the file COPYING. If not, write to
19 the Free Software Foundation, 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
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)");
159 #include "function.h"
160 #include "insn-config.h"
162 #include "hard-reg-set.h"
164 #include "insn-flags.h"
168 #include "basic-block.h"
173 #define REG_STACK_SIZE (LAST_STACK_REG - FIRST_STACK_REG + 1)
175 /* This is the basic stack record. TOP is an index into REG[] such
176 that REG[TOP] is the top of stack. If TOP is -1 the stack is empty.
178 If TOP is -2, REG[] is not yet initialized. Stack initialization
179 consists of placing each live reg in array `reg' and setting `top'
182 REG_SET indicates which registers are live. */
184 typedef struct stack_def
186 int top
; /* index to top stack element */
187 HARD_REG_SET reg_set
; /* set of live registers */
188 char reg
[REG_STACK_SIZE
]; /* register - stack mapping */
191 /* This is used to carry information about basic blocks. It is
192 attached to the AUX field of the standard CFG block. */
194 typedef struct block_info_def
196 struct stack_def stack_in
; /* Input stack configuration. */
197 HARD_REG_SET out_reg_set
; /* Stack regs live on output. */
198 int done
; /* True if block already converted. */
201 #define BLOCK_INFO(B) ((block_info) (B)->aux)
203 /* Passed to change_stack to indicate where to emit insns. */
210 /* We use this array to cache info about insns, because otherwise we
211 spend too much time in stack_regs_mentioned_p.
213 Indexed by insn UIDs. A value of zero is uninitialized, one indicates
214 the insn uses stack registers, two indicates the insn does not use
216 static varray_type stack_regs_mentioned_data
;
218 /* The block we're currently working on. */
219 static basic_block current_block
;
221 /* This is the register file for all register after conversion */
223 FP_mode_reg
[LAST_STACK_REG
+1-FIRST_STACK_REG
][(int) MAX_MACHINE_MODE
];
225 #define FP_MODE_REG(regno,mode) \
226 (FP_mode_reg[(regno)-FIRST_STACK_REG][(int)(mode)])
228 /* Used to initialize uninitialized registers. */
231 /* Forward declarations */
233 static int stack_regs_mentioned_p
PARAMS ((rtx pat
));
234 static void straighten_stack
PARAMS ((rtx
, stack
));
235 static void pop_stack
PARAMS ((stack
, int));
236 static rtx
*get_true_reg
PARAMS ((rtx
*));
238 static int check_asm_stack_operands
PARAMS ((rtx
));
239 static int get_asm_operand_n_inputs
PARAMS ((rtx
));
240 static rtx stack_result
PARAMS ((tree
));
241 static void replace_reg
PARAMS ((rtx
*, int));
242 static void remove_regno_note
PARAMS ((rtx
, enum reg_note
, int));
243 static int get_hard_regnum
PARAMS ((stack
, rtx
));
244 static void delete_insn_for_stacker
PARAMS ((rtx
));
245 static rtx emit_pop_insn
PARAMS ((rtx
, stack
, rtx
,
247 static void emit_swap_insn
PARAMS ((rtx
, stack
, rtx
));
248 static void move_for_stack_reg
PARAMS ((rtx
, stack
, rtx
));
249 static int swap_rtx_condition_1
PARAMS ((rtx
));
250 static int swap_rtx_condition
PARAMS ((rtx
));
251 static void compare_for_stack_reg
PARAMS ((rtx
, stack
, rtx
));
252 static void subst_stack_regs_pat
PARAMS ((rtx
, stack
, rtx
));
253 static void subst_asm_stack_regs
PARAMS ((rtx
, stack
));
254 static void subst_stack_regs
PARAMS ((rtx
, stack
));
255 static void change_stack
PARAMS ((rtx
, stack
, stack
,
257 static int convert_regs_entry
PARAMS ((void));
258 static void convert_regs_exit
PARAMS ((void));
259 static int convert_regs_1
PARAMS ((FILE *, basic_block
));
260 static int convert_regs_2
PARAMS ((FILE *, basic_block
));
261 static int convert_regs
PARAMS ((FILE *));
262 static void print_stack
PARAMS ((FILE *, stack
));
263 static rtx next_flags_user
PARAMS ((rtx
));
264 static void record_label_references
PARAMS ((rtx
, rtx
));
266 /* Return non-zero if any stack register is mentioned somewhere within PAT. */
269 stack_regs_mentioned_p (pat
)
272 register const char *fmt
;
275 if (STACK_REG_P (pat
))
278 fmt
= GET_RTX_FORMAT (GET_CODE (pat
));
279 for (i
= GET_RTX_LENGTH (GET_CODE (pat
)) - 1; i
>= 0; i
--)
285 for (j
= XVECLEN (pat
, i
) - 1; j
>= 0; j
--)
286 if (stack_regs_mentioned_p (XVECEXP (pat
, i
, j
)))
289 else if (fmt
[i
] == 'e' && stack_regs_mentioned_p (XEXP (pat
, i
)))
296 /* Return nonzero if INSN mentions stacked registers, else return zero. */
299 stack_regs_mentioned (insn
)
302 unsigned int uid
, max
;
308 uid
= INSN_UID (insn
);
309 max
= VARRAY_SIZE (stack_regs_mentioned_data
);
312 /* Allocate some extra size to avoid too many reallocs, but
313 do not grow too quickly. */
314 max
= uid
+ uid
/ 20;
315 VARRAY_GROW (stack_regs_mentioned_data
, max
);
318 test
= VARRAY_CHAR (stack_regs_mentioned_data
, uid
);
321 /* This insn has yet to be examined. Do so now. */
322 test
= stack_regs_mentioned_p (PATTERN (insn
)) ? 1 : 2;
323 VARRAY_CHAR (stack_regs_mentioned_data
, uid
) = test
;
329 static rtx ix86_flags_rtx
;
332 next_flags_user (insn
)
335 /* Search forward looking for the first use of this value.
336 Stop at block boundaries. */
338 while (insn
!= current_block
->end
)
340 insn
= NEXT_INSN (insn
);
342 if (INSN_P (insn
) && reg_mentioned_p (ix86_flags_rtx
, PATTERN (insn
)))
345 if (GET_CODE (insn
) == CALL_INSN
)
351 /* Reorganise the stack into ascending numbers,
355 straighten_stack (insn
, regstack
)
359 struct stack_def temp_stack
;
362 /* If there is only a single register on the stack, then the stack is
363 already in increasing order and no reorganization is needed.
365 Similarly if the stack is empty. */
366 if (regstack
->top
<= 0)
369 COPY_HARD_REG_SET (temp_stack
.reg_set
, regstack
->reg_set
);
371 for (top
= temp_stack
.top
= regstack
->top
; top
>= 0; top
--)
372 temp_stack
.reg
[top
] = FIRST_STACK_REG
+ temp_stack
.top
- top
;
374 change_stack (insn
, regstack
, &temp_stack
, EMIT_AFTER
);
377 /* Pop a register from the stack */
380 pop_stack (regstack
, regno
)
384 int top
= regstack
->top
;
386 CLEAR_HARD_REG_BIT (regstack
->reg_set
, regno
);
388 /* If regno was not at the top of stack then adjust stack */
389 if (regstack
->reg
[top
] != regno
)
392 for (i
= regstack
->top
; i
>= 0; i
--)
393 if (regstack
->reg
[i
] == regno
)
396 for (j
= i
; j
< top
; j
++)
397 regstack
->reg
[j
] = regstack
->reg
[j
+ 1];
403 /* Convert register usage from "flat" register file usage to a "stack
404 register file. FIRST is the first insn in the function, FILE is the
407 Construct a CFG and run life analysis. Then convert each insn one
408 by one. Run a last jump_optimize pass, if optimizing, to eliminate
409 code duplication created when the converter inserts pop insns on
413 reg_to_stack (first
, file
)
421 /* See if there is something to do. Flow analysis is quite
422 expensive so we might save some compilation time. */
423 for (i
= FIRST_STACK_REG
; i
<= LAST_STACK_REG
; i
++)
424 if (regs_ever_live
[i
])
426 if (i
> LAST_STACK_REG
)
429 /* Ok, floating point instructions exist. If not optimizing,
430 build the CFG and run life analysis. */
431 find_basic_blocks (first
, max_reg_num (), file
);
432 count_or_remove_death_notes (NULL
, 1);
433 life_analysis (first
, file
, PROP_DEATH_NOTES
);
435 /* Set up block info for each basic block. */
436 bi
= (block_info
) xcalloc ((n_basic_blocks
+ 1), sizeof (*bi
));
437 for (i
= n_basic_blocks
- 1; i
>= 0; --i
)
438 BASIC_BLOCK (i
)->aux
= bi
+ i
;
439 EXIT_BLOCK_PTR
->aux
= bi
+ n_basic_blocks
;
441 /* Create the replacement registers up front. */
442 for (i
= FIRST_STACK_REG
; i
<= LAST_STACK_REG
; i
++)
444 enum machine_mode mode
;
445 for (mode
= GET_CLASS_NARROWEST_MODE (MODE_FLOAT
);
447 mode
= GET_MODE_WIDER_MODE (mode
))
448 FP_MODE_REG (i
, mode
) = gen_rtx_REG (mode
, i
);
449 for (mode
= GET_CLASS_NARROWEST_MODE (MODE_COMPLEX_FLOAT
);
451 mode
= GET_MODE_WIDER_MODE (mode
))
452 FP_MODE_REG (i
, mode
) = gen_rtx_REG (mode
, i
);
455 ix86_flags_rtx
= gen_rtx_REG (CCmode
, FLAGS_REG
);
457 /* A QNaN for initializing uninitialized variables.
459 ??? We can't load from constant memory in PIC mode, because
460 we're insertting these instructions before the prologue and
461 the PIC register hasn't been set up. In that case, fall back
462 on zero, which we can get from `ldz'. */
465 nan
= CONST0_RTX (SFmode
);
468 nan
= gen_lowpart (SFmode
, GEN_INT (0x7fc00000));
469 nan
= force_const_mem (SFmode
, nan
);
472 /* Allocate a cache for stack_regs_mentioned. */
473 max_uid
= get_max_uid ();
474 VARRAY_CHAR_INIT (stack_regs_mentioned_data
, max_uid
+ 1,
475 "stack_regs_mentioned cache");
477 if (convert_regs (file
) && optimize
)
479 jump_optimize (first
, JUMP_CROSS_JUMP_DEATH_MATTERS
,
480 !JUMP_NOOP_MOVES
, !JUMP_AFTER_REGSCAN
);
484 VARRAY_FREE (stack_regs_mentioned_data
);
488 /* Check PAT, which is in INSN, for LABEL_REFs. Add INSN to the
489 label's chain of references, and note which insn contains each
493 record_label_references (insn
, pat
)
496 register enum rtx_code code
= GET_CODE (pat
);
498 register const char *fmt
;
500 if (code
== LABEL_REF
)
502 register rtx label
= XEXP (pat
, 0);
505 if (GET_CODE (label
) != CODE_LABEL
)
508 /* If this is an undefined label, LABEL_REFS (label) contains
510 if (INSN_UID (label
) == 0)
513 /* Don't make a duplicate in the code_label's chain. */
515 for (ref
= LABEL_REFS (label
);
517 ref
= LABEL_NEXTREF (ref
))
518 if (CONTAINING_INSN (ref
) == insn
)
521 CONTAINING_INSN (pat
) = insn
;
522 LABEL_NEXTREF (pat
) = LABEL_REFS (label
);
523 LABEL_REFS (label
) = pat
;
528 fmt
= GET_RTX_FORMAT (code
);
529 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
532 record_label_references (insn
, XEXP (pat
, i
));
536 for (j
= 0; j
< XVECLEN (pat
, i
); j
++)
537 record_label_references (insn
, XVECEXP (pat
, i
, j
));
542 /* Return a pointer to the REG expression within PAT. If PAT is not a
543 REG, possible enclosed by a conversion rtx, return the inner part of
544 PAT that stopped the search. */
551 switch (GET_CODE (*pat
))
554 /* Eliminate FP subregister accesses in favour of the
555 actual FP register in use. */
558 if (FP_REG_P (subreg
= SUBREG_REG (*pat
)))
560 *pat
= FP_MODE_REG (REGNO (subreg
) + SUBREG_WORD (*pat
),
569 pat
= & XEXP (*pat
, 0);
573 /* There are many rules that an asm statement for stack-like regs must
574 follow. Those rules are explained at the top of this file: the rule
575 numbers below refer to that explanation. */
578 check_asm_stack_operands (insn
)
583 int malformed_asm
= 0;
584 rtx body
= PATTERN (insn
);
586 char reg_used_as_output
[FIRST_PSEUDO_REGISTER
];
587 char implicitly_dies
[FIRST_PSEUDO_REGISTER
];
590 rtx
*clobber_reg
= 0;
591 int n_inputs
, n_outputs
;
593 /* Find out what the constraints require. If no constraint
594 alternative matches, this asm is malformed. */
596 constrain_operands (1);
597 alt
= which_alternative
;
599 preprocess_constraints ();
601 n_inputs
= get_asm_operand_n_inputs (body
);
602 n_outputs
= recog_data
.n_operands
- n_inputs
;
607 /* Avoid further trouble with this insn. */
608 PATTERN (insn
) = gen_rtx_USE (VOIDmode
, const0_rtx
);
612 /* Strip SUBREGs here to make the following code simpler. */
613 for (i
= 0; i
< recog_data
.n_operands
; i
++)
614 if (GET_CODE (recog_data
.operand
[i
]) == SUBREG
615 && GET_CODE (SUBREG_REG (recog_data
.operand
[i
])) == REG
)
616 recog_data
.operand
[i
] = SUBREG_REG (recog_data
.operand
[i
]);
618 /* Set up CLOBBER_REG. */
622 if (GET_CODE (body
) == PARALLEL
)
624 clobber_reg
= (rtx
*) alloca (XVECLEN (body
, 0) * sizeof (rtx
));
626 for (i
= 0; i
< XVECLEN (body
, 0); i
++)
627 if (GET_CODE (XVECEXP (body
, 0, i
)) == CLOBBER
)
629 rtx clobber
= XVECEXP (body
, 0, i
);
630 rtx reg
= XEXP (clobber
, 0);
632 if (GET_CODE (reg
) == SUBREG
&& GET_CODE (SUBREG_REG (reg
)) == REG
)
633 reg
= SUBREG_REG (reg
);
635 if (STACK_REG_P (reg
))
637 clobber_reg
[n_clobbers
] = reg
;
643 /* Enforce rule #4: Output operands must specifically indicate which
644 reg an output appears in after an asm. "=f" is not allowed: the
645 operand constraints must select a class with a single reg.
647 Also enforce rule #5: Output operands must start at the top of
648 the reg-stack: output operands may not "skip" a reg. */
650 memset (reg_used_as_output
, 0, sizeof (reg_used_as_output
));
651 for (i
= 0; i
< n_outputs
; i
++)
652 if (STACK_REG_P (recog_data
.operand
[i
]))
654 if (reg_class_size
[(int) recog_op_alt
[i
][alt
].class] != 1)
656 error_for_asm (insn
, "Output constraint %d must specify a single register", i
);
660 reg_used_as_output
[REGNO (recog_data
.operand
[i
])] = 1;
664 /* Search for first non-popped reg. */
665 for (i
= FIRST_STACK_REG
; i
< LAST_STACK_REG
+ 1; i
++)
666 if (! reg_used_as_output
[i
])
669 /* If there are any other popped regs, that's an error. */
670 for (; i
< LAST_STACK_REG
+ 1; i
++)
671 if (reg_used_as_output
[i
])
674 if (i
!= LAST_STACK_REG
+ 1)
676 error_for_asm (insn
, "Output regs must be grouped at top of stack");
680 /* Enforce rule #2: All implicitly popped input regs must be closer
681 to the top of the reg-stack than any input that is not implicitly
684 memset (implicitly_dies
, 0, sizeof (implicitly_dies
));
685 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
686 if (STACK_REG_P (recog_data
.operand
[i
]))
688 /* An input reg is implicitly popped if it is tied to an
689 output, or if there is a CLOBBER for it. */
692 for (j
= 0; j
< n_clobbers
; j
++)
693 if (operands_match_p (clobber_reg
[j
], recog_data
.operand
[i
]))
696 if (j
< n_clobbers
|| recog_op_alt
[i
][alt
].matches
>= 0)
697 implicitly_dies
[REGNO (recog_data
.operand
[i
])] = 1;
700 /* Search for first non-popped reg. */
701 for (i
= FIRST_STACK_REG
; i
< LAST_STACK_REG
+ 1; i
++)
702 if (! implicitly_dies
[i
])
705 /* If there are any other popped regs, that's an error. */
706 for (; i
< LAST_STACK_REG
+ 1; i
++)
707 if (implicitly_dies
[i
])
710 if (i
!= LAST_STACK_REG
+ 1)
713 "Implicitly popped regs must be grouped at top of stack");
717 /* Enfore rule #3: If any input operand uses the "f" constraint, all
718 output constraints must use the "&" earlyclobber.
720 ??? Detect this more deterministically by having constrain_asm_operands
721 record any earlyclobber. */
723 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
724 if (recog_op_alt
[i
][alt
].matches
== -1)
728 for (j
= 0; j
< n_outputs
; j
++)
729 if (operands_match_p (recog_data
.operand
[j
], recog_data
.operand
[i
]))
732 "Output operand %d must use `&' constraint", j
);
739 /* Avoid further trouble with this insn. */
740 PATTERN (insn
) = gen_rtx_USE (VOIDmode
, const0_rtx
);
747 /* Calculate the number of inputs and outputs in BODY, an
748 asm_operands. N_OPERANDS is the total number of operands, and
749 N_INPUTS and N_OUTPUTS are pointers to ints into which the results are
753 get_asm_operand_n_inputs (body
)
756 if (GET_CODE (body
) == SET
&& GET_CODE (SET_SRC (body
)) == ASM_OPERANDS
)
757 return ASM_OPERANDS_INPUT_LENGTH (SET_SRC (body
));
759 else if (GET_CODE (body
) == ASM_OPERANDS
)
760 return ASM_OPERANDS_INPUT_LENGTH (body
);
762 else if (GET_CODE (body
) == PARALLEL
763 && GET_CODE (XVECEXP (body
, 0, 0)) == SET
)
764 return ASM_OPERANDS_INPUT_LENGTH (SET_SRC (XVECEXP (body
, 0, 0)));
766 else if (GET_CODE (body
) == PARALLEL
767 && GET_CODE (XVECEXP (body
, 0, 0)) == ASM_OPERANDS
)
768 return ASM_OPERANDS_INPUT_LENGTH (XVECEXP (body
, 0, 0));
773 /* If current function returns its result in an fp stack register,
774 return the REG. Otherwise, return 0. */
782 /* If the value is supposed to be returned in memory, then clearly
783 it is not returned in a stack register. */
784 if (aggregate_value_p (DECL_RESULT (decl
)))
787 result
= DECL_RTL_IF_SET (DECL_RESULT (decl
));
790 #ifdef FUNCTION_OUTGOING_VALUE
792 = FUNCTION_OUTGOING_VALUE (TREE_TYPE (DECL_RESULT (decl
)), decl
);
794 result
= FUNCTION_VALUE (TREE_TYPE (DECL_RESULT (decl
)), decl
);
798 return result
!= 0 && STACK_REG_P (result
) ? result
: 0;
803 * This section deals with stack register substitution, and forms the second
807 /* Replace REG, which is a pointer to a stack reg RTX, with an RTX for
808 the desired hard REGNO. */
811 replace_reg (reg
, regno
)
815 if (regno
< FIRST_STACK_REG
|| regno
> LAST_STACK_REG
816 || ! STACK_REG_P (*reg
))
819 switch (GET_MODE_CLASS (GET_MODE (*reg
)))
823 case MODE_COMPLEX_FLOAT
:;
826 *reg
= FP_MODE_REG (regno
, GET_MODE (*reg
));
829 /* Remove a note of type NOTE, which must be found, for register
830 number REGNO from INSN. Remove only one such note. */
833 remove_regno_note (insn
, note
, regno
)
838 register rtx
*note_link
, this;
840 note_link
= ®_NOTES(insn
);
841 for (this = *note_link
; this; this = XEXP (this, 1))
842 if (REG_NOTE_KIND (this) == note
843 && REG_P (XEXP (this, 0)) && REGNO (XEXP (this, 0)) == regno
)
845 *note_link
= XEXP (this, 1);
849 note_link
= &XEXP (this, 1);
854 /* Find the hard register number of virtual register REG in REGSTACK.
855 The hard register number is relative to the top of the stack. -1 is
856 returned if the register is not found. */
859 get_hard_regnum (regstack
, reg
)
865 if (! STACK_REG_P (reg
))
868 for (i
= regstack
->top
; i
>= 0; i
--)
869 if (regstack
->reg
[i
] == REGNO (reg
))
872 return i
>= 0 ? (FIRST_STACK_REG
+ regstack
->top
- i
) : -1;
875 /* Delete INSN from the RTL. Mark the insn, but don't remove it from
876 the chain of insns. Doing so could confuse block_begin and block_end
877 if this were the only insn in the block. */
880 delete_insn_for_stacker (insn
)
883 PUT_CODE (insn
, NOTE
);
884 NOTE_LINE_NUMBER (insn
) = NOTE_INSN_DELETED
;
885 NOTE_SOURCE_FILE (insn
) = 0;
888 /* Emit an insn to pop virtual register REG before or after INSN.
889 REGSTACK is the stack state after INSN and is updated to reflect this
890 pop. WHEN is either emit_insn_before or emit_insn_after. A pop insn
891 is represented as a SET whose destination is the register to be popped
892 and source is the top of stack. A death note for the top of stack
893 cases the movdf pattern to pop. */
896 emit_pop_insn (insn
, regstack
, reg
, where
)
900 enum emit_where where
;
902 rtx pop_insn
, pop_rtx
;
905 hard_regno
= get_hard_regnum (regstack
, reg
);
907 if (hard_regno
< FIRST_STACK_REG
)
910 pop_rtx
= gen_rtx_SET (VOIDmode
, FP_MODE_REG (hard_regno
, DFmode
),
911 FP_MODE_REG (FIRST_STACK_REG
, DFmode
));
913 if (where
== EMIT_AFTER
)
914 pop_insn
= emit_block_insn_after (pop_rtx
, insn
, current_block
);
916 pop_insn
= emit_block_insn_before (pop_rtx
, insn
, current_block
);
919 = gen_rtx_EXPR_LIST (REG_DEAD
, FP_MODE_REG (FIRST_STACK_REG
, DFmode
),
920 REG_NOTES (pop_insn
));
922 regstack
->reg
[regstack
->top
- (hard_regno
- FIRST_STACK_REG
)]
923 = regstack
->reg
[regstack
->top
];
925 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (reg
));
930 /* Emit an insn before or after INSN to swap virtual register REG with
931 the top of stack. REGSTACK is the stack state before the swap, and
932 is updated to reflect the swap. A swap insn is represented as a
933 PARALLEL of two patterns: each pattern moves one reg to the other.
935 If REG is already at the top of the stack, no insn is emitted. */
938 emit_swap_insn (insn
, regstack
, reg
)
945 int tmp
, other_reg
; /* swap regno temps */
946 rtx i1
; /* the stack-reg insn prior to INSN */
947 rtx i1set
= NULL_RTX
; /* the SET rtx within I1 */
949 hard_regno
= get_hard_regnum (regstack
, reg
);
951 if (hard_regno
< FIRST_STACK_REG
)
953 if (hard_regno
== FIRST_STACK_REG
)
956 other_reg
= regstack
->top
- (hard_regno
- FIRST_STACK_REG
);
958 tmp
= regstack
->reg
[other_reg
];
959 regstack
->reg
[other_reg
] = regstack
->reg
[regstack
->top
];
960 regstack
->reg
[regstack
->top
] = tmp
;
962 /* Find the previous insn involving stack regs, but don't pass a
965 if (current_block
&& insn
!= current_block
->head
)
967 rtx tmp
= PREV_INSN (insn
);
968 rtx limit
= PREV_INSN (current_block
->head
);
971 if (GET_CODE (tmp
) == CODE_LABEL
972 || NOTE_INSN_BASIC_BLOCK_P (tmp
)
973 || (GET_CODE (tmp
) == INSN
974 && stack_regs_mentioned (tmp
)))
979 tmp
= PREV_INSN (tmp
);
984 && (i1set
= single_set (i1
)) != NULL_RTX
)
986 rtx i1src
= *get_true_reg (&SET_SRC (i1set
));
987 rtx i1dest
= *get_true_reg (&SET_DEST (i1set
));
989 /* If the previous register stack push was from the reg we are to
990 swap with, omit the swap. */
992 if (GET_CODE (i1dest
) == REG
&& REGNO (i1dest
) == FIRST_STACK_REG
993 && GET_CODE (i1src
) == REG
&& REGNO (i1src
) == hard_regno
- 1
994 && find_regno_note (i1
, REG_DEAD
, FIRST_STACK_REG
) == NULL_RTX
)
997 /* If the previous insn wrote to the reg we are to swap with,
1000 if (GET_CODE (i1dest
) == REG
&& REGNO (i1dest
) == hard_regno
1001 && GET_CODE (i1src
) == REG
&& REGNO (i1src
) == FIRST_STACK_REG
1002 && find_regno_note (i1
, REG_DEAD
, FIRST_STACK_REG
) == NULL_RTX
)
1006 swap_rtx
= gen_swapxf (FP_MODE_REG (hard_regno
, XFmode
),
1007 FP_MODE_REG (FIRST_STACK_REG
, XFmode
));
1010 emit_block_insn_after (swap_rtx
, i1
, current_block
);
1011 else if (current_block
)
1012 emit_block_insn_before (swap_rtx
, current_block
->head
, current_block
);
1014 emit_insn_before (swap_rtx
, insn
);
1017 /* Handle a move to or from a stack register in PAT, which is in INSN.
1018 REGSTACK is the current stack. */
1021 move_for_stack_reg (insn
, regstack
, pat
)
1026 rtx
*psrc
= get_true_reg (&SET_SRC (pat
));
1027 rtx
*pdest
= get_true_reg (&SET_DEST (pat
));
1031 src
= *psrc
; dest
= *pdest
;
1033 if (STACK_REG_P (src
) && STACK_REG_P (dest
))
1035 /* Write from one stack reg to another. If SRC dies here, then
1036 just change the register mapping and delete the insn. */
1038 note
= find_regno_note (insn
, REG_DEAD
, REGNO (src
));
1043 /* If this is a no-op move, there must not be a REG_DEAD note. */
1044 if (REGNO (src
) == REGNO (dest
))
1047 for (i
= regstack
->top
; i
>= 0; i
--)
1048 if (regstack
->reg
[i
] == REGNO (src
))
1051 /* The source must be live, and the dest must be dead. */
1052 if (i
< 0 || get_hard_regnum (regstack
, dest
) >= FIRST_STACK_REG
)
1055 /* It is possible that the dest is unused after this insn.
1056 If so, just pop the src. */
1058 if (find_regno_note (insn
, REG_UNUSED
, REGNO (dest
)))
1060 emit_pop_insn (insn
, regstack
, src
, EMIT_AFTER
);
1062 delete_insn_for_stacker (insn
);
1066 regstack
->reg
[i
] = REGNO (dest
);
1068 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (dest
));
1069 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (src
));
1071 delete_insn_for_stacker (insn
);
1076 /* The source reg does not die. */
1078 /* If this appears to be a no-op move, delete it, or else it
1079 will confuse the machine description output patterns. But if
1080 it is REG_UNUSED, we must pop the reg now, as per-insn processing
1081 for REG_UNUSED will not work for deleted insns. */
1083 if (REGNO (src
) == REGNO (dest
))
1085 if (find_regno_note (insn
, REG_UNUSED
, REGNO (dest
)))
1086 emit_pop_insn (insn
, regstack
, dest
, EMIT_AFTER
);
1088 delete_insn_for_stacker (insn
);
1092 /* The destination ought to be dead */
1093 if (get_hard_regnum (regstack
, dest
) >= FIRST_STACK_REG
)
1096 replace_reg (psrc
, get_hard_regnum (regstack
, src
));
1098 regstack
->reg
[++regstack
->top
] = REGNO (dest
);
1099 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (dest
));
1100 replace_reg (pdest
, FIRST_STACK_REG
);
1102 else if (STACK_REG_P (src
))
1104 /* Save from a stack reg to MEM, or possibly integer reg. Since
1105 only top of stack may be saved, emit an exchange first if
1108 emit_swap_insn (insn
, regstack
, src
);
1110 note
= find_regno_note (insn
, REG_DEAD
, REGNO (src
));
1113 replace_reg (&XEXP (note
, 0), FIRST_STACK_REG
);
1115 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (src
));
1117 else if ((GET_MODE (src
) == XFmode
|| GET_MODE (src
) == TFmode
)
1118 && regstack
->top
< REG_STACK_SIZE
- 1)
1120 /* A 387 cannot write an XFmode value to a MEM without
1121 clobbering the source reg. The output code can handle
1122 this by reading back the value from the MEM.
1123 But it is more efficient to use a temp register if one is
1124 available. Push the source value here if the register
1125 stack is not full, and then write the value to memory via
1127 rtx push_rtx
, push_insn
;
1128 rtx top_stack_reg
= FP_MODE_REG (FIRST_STACK_REG
, XFmode
);
1130 push_rtx
= gen_movxf (top_stack_reg
, top_stack_reg
);
1131 push_insn
= emit_insn_before (push_rtx
, insn
);
1132 REG_NOTES (insn
) = gen_rtx_EXPR_LIST (REG_DEAD
, top_stack_reg
,
1136 replace_reg (psrc
, FIRST_STACK_REG
);
1138 else if (STACK_REG_P (dest
))
1140 /* Load from MEM, or possibly integer REG or constant, into the
1141 stack regs. The actual target is always the top of the
1142 stack. The stack mapping is changed to reflect that DEST is
1143 now at top of stack. */
1145 /* The destination ought to be dead */
1146 if (get_hard_regnum (regstack
, dest
) >= FIRST_STACK_REG
)
1149 if (regstack
->top
>= REG_STACK_SIZE
)
1152 regstack
->reg
[++regstack
->top
] = REGNO (dest
);
1153 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (dest
));
1154 replace_reg (pdest
, FIRST_STACK_REG
);
1160 /* Swap the condition on a branch, if there is one. Return true if we
1161 found a condition to swap. False if the condition was not used as
1165 swap_rtx_condition_1 (pat
)
1168 register const char *fmt
;
1169 register int i
, r
= 0;
1171 if (GET_RTX_CLASS (GET_CODE (pat
)) == '<')
1173 PUT_CODE (pat
, swap_condition (GET_CODE (pat
)));
1178 fmt
= GET_RTX_FORMAT (GET_CODE (pat
));
1179 for (i
= GET_RTX_LENGTH (GET_CODE (pat
)) - 1; i
>= 0; i
--)
1185 for (j
= XVECLEN (pat
, i
) - 1; j
>= 0; j
--)
1186 r
|= swap_rtx_condition_1 (XVECEXP (pat
, i
, j
));
1188 else if (fmt
[i
] == 'e')
1189 r
|= swap_rtx_condition_1 (XEXP (pat
, i
));
1197 swap_rtx_condition (insn
)
1200 rtx pat
= PATTERN (insn
);
1202 /* We're looking for a single set to cc0 or an HImode temporary. */
1204 if (GET_CODE (pat
) == SET
1205 && GET_CODE (SET_DEST (pat
)) == REG
1206 && REGNO (SET_DEST (pat
)) == FLAGS_REG
)
1208 insn
= next_flags_user (insn
);
1209 if (insn
== NULL_RTX
)
1211 pat
= PATTERN (insn
);
1214 /* See if this is, or ends in, a fnstsw, aka unspec 9. If so, we're
1215 not doing anything with the cc value right now. We may be able to
1216 search for one though. */
1218 if (GET_CODE (pat
) == SET
1219 && GET_CODE (SET_SRC (pat
)) == UNSPEC
1220 && XINT (SET_SRC (pat
), 1) == 9)
1222 rtx dest
= SET_DEST (pat
);
1224 /* Search forward looking for the first use of this value.
1225 Stop at block boundaries. */
1226 while (insn
!= current_block
->end
)
1228 insn
= NEXT_INSN (insn
);
1229 if (INSN_P (insn
) && reg_mentioned_p (dest
, insn
))
1231 if (GET_CODE (insn
) == CALL_INSN
)
1235 /* So we've found the insn using this value. If it is anything
1236 other than sahf, aka unspec 10, or the value does not die
1237 (meaning we'd have to search further), then we must give up. */
1238 pat
= PATTERN (insn
);
1239 if (GET_CODE (pat
) != SET
1240 || GET_CODE (SET_SRC (pat
)) != UNSPEC
1241 || XINT (SET_SRC (pat
), 1) != 10
1242 || ! dead_or_set_p (insn
, dest
))
1245 /* Now we are prepared to handle this as a normal cc0 setter. */
1246 insn
= next_flags_user (insn
);
1247 if (insn
== NULL_RTX
)
1249 pat
= PATTERN (insn
);
1252 if (swap_rtx_condition_1 (pat
))
1255 INSN_CODE (insn
) = -1;
1256 if (recog_memoized (insn
) == -1)
1258 /* In case the flags don't die here, recurse to try fix
1259 following user too. */
1260 else if (! dead_or_set_p (insn
, ix86_flags_rtx
))
1262 insn
= next_flags_user (insn
);
1263 if (!insn
|| !swap_rtx_condition (insn
))
1268 swap_rtx_condition_1 (pat
);
1276 /* Handle a comparison. Special care needs to be taken to avoid
1277 causing comparisons that a 387 cannot do correctly, such as EQ.
1279 Also, a pop insn may need to be emitted. The 387 does have an
1280 `fcompp' insn that can pop two regs, but it is sometimes too expensive
1281 to do this - a `fcomp' followed by a `fstpl %st(0)' may be easier to
1285 compare_for_stack_reg (insn
, regstack
, pat_src
)
1291 rtx src1_note
, src2_note
;
1294 src1
= get_true_reg (&XEXP (pat_src
, 0));
1295 src2
= get_true_reg (&XEXP (pat_src
, 1));
1296 flags_user
= next_flags_user (insn
);
1298 /* ??? If fxch turns out to be cheaper than fstp, give priority to
1299 registers that die in this insn - move those to stack top first. */
1300 if ((! STACK_REG_P (*src1
)
1301 || (STACK_REG_P (*src2
)
1302 && get_hard_regnum (regstack
, *src2
) == FIRST_STACK_REG
))
1303 && swap_rtx_condition (insn
))
1306 temp
= XEXP (pat_src
, 0);
1307 XEXP (pat_src
, 0) = XEXP (pat_src
, 1);
1308 XEXP (pat_src
, 1) = temp
;
1310 src1
= get_true_reg (&XEXP (pat_src
, 0));
1311 src2
= get_true_reg (&XEXP (pat_src
, 1));
1313 INSN_CODE (insn
) = -1;
1316 /* We will fix any death note later. */
1318 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1320 if (STACK_REG_P (*src2
))
1321 src2_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src2
));
1323 src2_note
= NULL_RTX
;
1325 emit_swap_insn (insn
, regstack
, *src1
);
1327 replace_reg (src1
, FIRST_STACK_REG
);
1329 if (STACK_REG_P (*src2
))
1330 replace_reg (src2
, get_hard_regnum (regstack
, *src2
));
1334 pop_stack (regstack
, REGNO (XEXP (src1_note
, 0)));
1335 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1338 /* If the second operand dies, handle that. But if the operands are
1339 the same stack register, don't bother, because only one death is
1340 needed, and it was just handled. */
1343 && ! (STACK_REG_P (*src1
) && STACK_REG_P (*src2
)
1344 && REGNO (*src1
) == REGNO (*src2
)))
1346 /* As a special case, two regs may die in this insn if src2 is
1347 next to top of stack and the top of stack also dies. Since
1348 we have already popped src1, "next to top of stack" is really
1349 at top (FIRST_STACK_REG) now. */
1351 if (get_hard_regnum (regstack
, XEXP (src2_note
, 0)) == FIRST_STACK_REG
1354 pop_stack (regstack
, REGNO (XEXP (src2_note
, 0)));
1355 replace_reg (&XEXP (src2_note
, 0), FIRST_STACK_REG
+ 1);
1359 /* The 386 can only represent death of the first operand in
1360 the case handled above. In all other cases, emit a separate
1361 pop and remove the death note from here. */
1363 /* link_cc0_insns (insn); */
1365 remove_regno_note (insn
, REG_DEAD
, REGNO (XEXP (src2_note
, 0)));
1367 emit_pop_insn (insn
, regstack
, XEXP (src2_note
, 0),
1373 /* Substitute new registers in PAT, which is part of INSN. REGSTACK
1374 is the current register layout. */
1377 subst_stack_regs_pat (insn
, regstack
, pat
)
1384 switch (GET_CODE (pat
))
1387 /* Deaths in USE insns can happen in non optimizing compilation.
1388 Handle them by popping the dying register. */
1389 src
= get_true_reg (&XEXP (pat
, 0));
1390 if (STACK_REG_P (*src
)
1391 && find_regno_note (insn
, REG_DEAD
, REGNO (*src
)))
1393 emit_pop_insn (insn
, regstack
, *src
, EMIT_AFTER
);
1396 /* ??? Uninitialized USE should not happen. */
1397 else if (get_hard_regnum (regstack
, *src
) == -1)
1405 dest
= get_true_reg (&XEXP (pat
, 0));
1406 if (STACK_REG_P (*dest
))
1408 note
= find_reg_note (insn
, REG_DEAD
, *dest
);
1410 if (pat
!= PATTERN (insn
))
1412 /* The fix_truncdi_1 pattern wants to be able to allocate
1413 it's own scratch register. It does this by clobbering
1414 an fp reg so that it is assured of an empty reg-stack
1415 register. If the register is live, kill it now.
1416 Remove the DEAD/UNUSED note so we don't try to kill it
1420 emit_pop_insn (insn
, regstack
, *dest
, EMIT_BEFORE
);
1423 note
= find_reg_note (insn
, REG_UNUSED
, *dest
);
1427 remove_note (insn
, note
);
1428 replace_reg (dest
, LAST_STACK_REG
);
1432 /* A top-level clobber with no REG_DEAD, and no hard-regnum
1433 indicates an uninitialized value. Because reload removed
1434 all other clobbers, this must be due to a function
1435 returning without a value. Load up a NaN. */
1438 && get_hard_regnum (regstack
, *dest
) == -1)
1440 pat
= gen_rtx_SET (VOIDmode
,
1441 FP_MODE_REG (REGNO (*dest
), SFmode
),
1443 PATTERN (insn
) = pat
;
1444 move_for_stack_reg (insn
, regstack
, pat
);
1453 rtx
*src1
= (rtx
*) NULL_PTR
, *src2
;
1454 rtx src1_note
, src2_note
;
1457 dest
= get_true_reg (&SET_DEST (pat
));
1458 src
= get_true_reg (&SET_SRC (pat
));
1459 pat_src
= SET_SRC (pat
);
1461 /* See if this is a `movM' pattern, and handle elsewhere if so. */
1462 if (STACK_REG_P (*src
)
1463 || (STACK_REG_P (*dest
)
1464 && (GET_CODE (*src
) == REG
|| GET_CODE (*src
) == MEM
1465 || GET_CODE (*src
) == CONST_DOUBLE
)))
1467 move_for_stack_reg (insn
, regstack
, pat
);
1471 switch (GET_CODE (pat_src
))
1474 compare_for_stack_reg (insn
, regstack
, pat_src
);
1480 for (count
= HARD_REGNO_NREGS (REGNO (*dest
), GET_MODE (*dest
));
1483 regstack
->reg
[++regstack
->top
] = REGNO (*dest
) + count
;
1484 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
) + count
);
1487 replace_reg (dest
, FIRST_STACK_REG
);
1491 /* This is a `tstM2' case. */
1492 if (*dest
!= cc0_rtx
)
1498 case FLOAT_TRUNCATE
:
1502 /* These insns only operate on the top of the stack. DEST might
1503 be cc0_rtx if we're processing a tstM pattern. Also, it's
1504 possible that the tstM case results in a REG_DEAD note on the
1508 src1
= get_true_reg (&XEXP (pat_src
, 0));
1510 emit_swap_insn (insn
, regstack
, *src1
);
1512 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1514 if (STACK_REG_P (*dest
))
1515 replace_reg (dest
, FIRST_STACK_REG
);
1519 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1521 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (*src1
));
1524 replace_reg (src1
, FIRST_STACK_REG
);
1529 /* On i386, reversed forms of subM3 and divM3 exist for
1530 MODE_FLOAT, so the same code that works for addM3 and mulM3
1534 /* These insns can accept the top of stack as a destination
1535 from a stack reg or mem, or can use the top of stack as a
1536 source and some other stack register (possibly top of stack)
1537 as a destination. */
1539 src1
= get_true_reg (&XEXP (pat_src
, 0));
1540 src2
= get_true_reg (&XEXP (pat_src
, 1));
1542 /* We will fix any death note later. */
1544 if (STACK_REG_P (*src1
))
1545 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1547 src1_note
= NULL_RTX
;
1548 if (STACK_REG_P (*src2
))
1549 src2_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src2
));
1551 src2_note
= NULL_RTX
;
1553 /* If either operand is not a stack register, then the dest
1554 must be top of stack. */
1556 if (! STACK_REG_P (*src1
) || ! STACK_REG_P (*src2
))
1557 emit_swap_insn (insn
, regstack
, *dest
);
1560 /* Both operands are REG. If neither operand is already
1561 at the top of stack, choose to make the one that is the dest
1562 the new top of stack. */
1564 int src1_hard_regnum
, src2_hard_regnum
;
1566 src1_hard_regnum
= get_hard_regnum (regstack
, *src1
);
1567 src2_hard_regnum
= get_hard_regnum (regstack
, *src2
);
1568 if (src1_hard_regnum
== -1 || src2_hard_regnum
== -1)
1571 if (src1_hard_regnum
!= FIRST_STACK_REG
1572 && src2_hard_regnum
!= FIRST_STACK_REG
)
1573 emit_swap_insn (insn
, regstack
, *dest
);
1576 if (STACK_REG_P (*src1
))
1577 replace_reg (src1
, get_hard_regnum (regstack
, *src1
));
1578 if (STACK_REG_P (*src2
))
1579 replace_reg (src2
, get_hard_regnum (regstack
, *src2
));
1583 rtx src1_reg
= XEXP (src1_note
, 0);
1585 /* If the register that dies is at the top of stack, then
1586 the destination is somewhere else - merely substitute it.
1587 But if the reg that dies is not at top of stack, then
1588 move the top of stack to the dead reg, as though we had
1589 done the insn and then a store-with-pop. */
1591 if (REGNO (src1_reg
) == regstack
->reg
[regstack
->top
])
1593 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1594 replace_reg (dest
, get_hard_regnum (regstack
, *dest
));
1598 int regno
= get_hard_regnum (regstack
, src1_reg
);
1600 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1601 replace_reg (dest
, regno
);
1603 regstack
->reg
[regstack
->top
- (regno
- FIRST_STACK_REG
)]
1604 = regstack
->reg
[regstack
->top
];
1607 CLEAR_HARD_REG_BIT (regstack
->reg_set
,
1608 REGNO (XEXP (src1_note
, 0)));
1609 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1614 rtx src2_reg
= XEXP (src2_note
, 0);
1615 if (REGNO (src2_reg
) == regstack
->reg
[regstack
->top
])
1617 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1618 replace_reg (dest
, get_hard_regnum (regstack
, *dest
));
1622 int regno
= get_hard_regnum (regstack
, src2_reg
);
1624 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1625 replace_reg (dest
, regno
);
1627 regstack
->reg
[regstack
->top
- (regno
- FIRST_STACK_REG
)]
1628 = regstack
->reg
[regstack
->top
];
1631 CLEAR_HARD_REG_BIT (regstack
->reg_set
,
1632 REGNO (XEXP (src2_note
, 0)));
1633 replace_reg (&XEXP (src2_note
, 0), FIRST_STACK_REG
);
1638 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1639 replace_reg (dest
, get_hard_regnum (regstack
, *dest
));
1642 /* Keep operand 1 maching with destination. */
1643 if (GET_RTX_CLASS (GET_CODE (pat_src
)) == 'c'
1644 && REG_P (*src1
) && REG_P (*src2
)
1645 && REGNO (*src1
) != REGNO (*dest
))
1647 int tmp
= REGNO (*src1
);
1648 replace_reg (src1
, REGNO (*src2
));
1649 replace_reg (src2
, tmp
);
1654 switch (XINT (pat_src
, 1))
1658 /* These insns only operate on the top of the stack. */
1660 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1662 emit_swap_insn (insn
, regstack
, *src1
);
1664 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1666 if (STACK_REG_P (*dest
))
1667 replace_reg (dest
, FIRST_STACK_REG
);
1671 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1673 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (*src1
));
1676 replace_reg (src1
, FIRST_STACK_REG
);
1680 /* (unspec [(unspec [(compare ..)] 9)] 10)
1681 Unspec 9 is fnstsw; unspec 10 is sahf. The combination
1682 matches the PPRO fcomi instruction. */
1684 pat_src
= XVECEXP (pat_src
, 0, 0);
1685 if (GET_CODE (pat_src
) != UNSPEC
1686 || XINT (pat_src
, 1) != 9)
1691 /* (unspec [(compare ..)] 9) */
1692 /* Combined fcomp+fnstsw generated for doing well with
1693 CSE. When optimizing this would have been broken
1696 pat_src
= XVECEXP (pat_src
, 0, 0);
1697 if (GET_CODE (pat_src
) != COMPARE
)
1700 compare_for_stack_reg (insn
, regstack
, pat_src
);
1709 /* This insn requires the top of stack to be the destination. */
1711 /* If the comparison operator is an FP comparison operator,
1712 it is handled correctly by compare_for_stack_reg () who
1713 will move the destination to the top of stack. But if the
1714 comparison operator is not an FP comparison operator, we
1715 have to handle it here. */
1716 if (get_hard_regnum (regstack
, *dest
) >= FIRST_STACK_REG
1717 && REGNO (*dest
) != regstack
->reg
[regstack
->top
])
1718 emit_swap_insn (insn
, regstack
, *dest
);
1720 src1
= get_true_reg (&XEXP (pat_src
, 1));
1721 src2
= get_true_reg (&XEXP (pat_src
, 2));
1723 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1724 src2_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src2
));
1731 src_note
[1] = src1_note
;
1732 src_note
[2] = src2_note
;
1734 if (STACK_REG_P (*src1
))
1735 replace_reg (src1
, get_hard_regnum (regstack
, *src1
));
1736 if (STACK_REG_P (*src2
))
1737 replace_reg (src2
, get_hard_regnum (regstack
, *src2
));
1739 for (i
= 1; i
<= 2; i
++)
1742 int regno
= REGNO (XEXP (src_note
[i
], 0));
1744 /* If the register that dies is not at the top of
1745 stack, then move the top of stack to the dead reg */
1746 if (regno
!= regstack
->reg
[regstack
->top
])
1748 remove_regno_note (insn
, REG_DEAD
, regno
);
1749 emit_pop_insn (insn
, regstack
, XEXP (src_note
[i
], 0),
1754 CLEAR_HARD_REG_BIT (regstack
->reg_set
, regno
);
1755 replace_reg (&XEXP (src_note
[i
], 0), FIRST_STACK_REG
);
1761 /* Make dest the top of stack. Add dest to regstack if
1763 if (get_hard_regnum (regstack
, *dest
) < FIRST_STACK_REG
)
1764 regstack
->reg
[++regstack
->top
] = REGNO (*dest
);
1765 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1766 replace_reg (dest
, FIRST_STACK_REG
);
1780 /* Substitute hard regnums for any stack regs in INSN, which has
1781 N_INPUTS inputs and N_OUTPUTS outputs. REGSTACK is the stack info
1782 before the insn, and is updated with changes made here.
1784 There are several requirements and assumptions about the use of
1785 stack-like regs in asm statements. These rules are enforced by
1786 record_asm_stack_regs; see comments there for details. Any
1787 asm_operands left in the RTL at this point may be assume to meet the
1788 requirements, since record_asm_stack_regs removes any problem asm. */
1791 subst_asm_stack_regs (insn
, regstack
)
1795 rtx body
= PATTERN (insn
);
1798 rtx
*note_reg
; /* Array of note contents */
1799 rtx
**note_loc
; /* Address of REG field of each note */
1800 enum reg_note
*note_kind
; /* The type of each note */
1802 rtx
*clobber_reg
= 0;
1803 rtx
**clobber_loc
= 0;
1805 struct stack_def temp_stack
;
1810 int n_inputs
, n_outputs
;
1812 if (! check_asm_stack_operands (insn
))
1815 /* Find out what the constraints required. If no constraint
1816 alternative matches, that is a compiler bug: we should have caught
1817 such an insn in check_asm_stack_operands. */
1818 extract_insn (insn
);
1819 constrain_operands (1);
1820 alt
= which_alternative
;
1822 preprocess_constraints ();
1824 n_inputs
= get_asm_operand_n_inputs (body
);
1825 n_outputs
= recog_data
.n_operands
- n_inputs
;
1830 /* Strip SUBREGs here to make the following code simpler. */
1831 for (i
= 0; i
< recog_data
.n_operands
; i
++)
1832 if (GET_CODE (recog_data
.operand
[i
]) == SUBREG
1833 && GET_CODE (SUBREG_REG (recog_data
.operand
[i
])) == REG
)
1835 recog_data
.operand_loc
[i
] = & SUBREG_REG (recog_data
.operand
[i
]);
1836 recog_data
.operand
[i
] = SUBREG_REG (recog_data
.operand
[i
]);
1839 /* Set up NOTE_REG, NOTE_LOC and NOTE_KIND. */
1841 for (i
= 0, note
= REG_NOTES (insn
); note
; note
= XEXP (note
, 1))
1844 note_reg
= (rtx
*) alloca (i
* sizeof (rtx
));
1845 note_loc
= (rtx
**) alloca (i
* sizeof (rtx
*));
1846 note_kind
= (enum reg_note
*) alloca (i
* sizeof (enum reg_note
));
1849 for (note
= REG_NOTES (insn
); note
; note
= XEXP (note
, 1))
1851 rtx reg
= XEXP (note
, 0);
1852 rtx
*loc
= & XEXP (note
, 0);
1854 if (GET_CODE (reg
) == SUBREG
&& GET_CODE (SUBREG_REG (reg
)) == REG
)
1856 loc
= & SUBREG_REG (reg
);
1857 reg
= SUBREG_REG (reg
);
1860 if (STACK_REG_P (reg
)
1861 && (REG_NOTE_KIND (note
) == REG_DEAD
1862 || REG_NOTE_KIND (note
) == REG_UNUSED
))
1864 note_reg
[n_notes
] = reg
;
1865 note_loc
[n_notes
] = loc
;
1866 note_kind
[n_notes
] = REG_NOTE_KIND (note
);
1871 /* Set up CLOBBER_REG and CLOBBER_LOC. */
1875 if (GET_CODE (body
) == PARALLEL
)
1877 clobber_reg
= (rtx
*) alloca (XVECLEN (body
, 0) * sizeof (rtx
));
1878 clobber_loc
= (rtx
**) alloca (XVECLEN (body
, 0) * sizeof (rtx
*));
1880 for (i
= 0; i
< XVECLEN (body
, 0); i
++)
1881 if (GET_CODE (XVECEXP (body
, 0, i
)) == CLOBBER
)
1883 rtx clobber
= XVECEXP (body
, 0, i
);
1884 rtx reg
= XEXP (clobber
, 0);
1885 rtx
*loc
= & XEXP (clobber
, 0);
1887 if (GET_CODE (reg
) == SUBREG
&& GET_CODE (SUBREG_REG (reg
)) == REG
)
1889 loc
= & SUBREG_REG (reg
);
1890 reg
= SUBREG_REG (reg
);
1893 if (STACK_REG_P (reg
))
1895 clobber_reg
[n_clobbers
] = reg
;
1896 clobber_loc
[n_clobbers
] = loc
;
1902 temp_stack
= *regstack
;
1904 /* Put the input regs into the desired place in TEMP_STACK. */
1906 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
1907 if (STACK_REG_P (recog_data
.operand
[i
])
1908 && reg_class_subset_p (recog_op_alt
[i
][alt
].class,
1910 && recog_op_alt
[i
][alt
].class != FLOAT_REGS
)
1912 /* If an operand needs to be in a particular reg in
1913 FLOAT_REGS, the constraint was either 't' or 'u'. Since
1914 these constraints are for single register classes, and
1915 reload guaranteed that operand[i] is already in that class,
1916 we can just use REGNO (recog_data.operand[i]) to know which
1917 actual reg this operand needs to be in. */
1919 int regno
= get_hard_regnum (&temp_stack
, recog_data
.operand
[i
]);
1924 if (regno
!= REGNO (recog_data
.operand
[i
]))
1926 /* recog_data.operand[i] is not in the right place. Find
1927 it and swap it with whatever is already in I's place.
1928 K is where recog_data.operand[i] is now. J is where it
1932 k
= temp_stack
.top
- (regno
- FIRST_STACK_REG
);
1934 - (REGNO (recog_data
.operand
[i
]) - FIRST_STACK_REG
));
1936 temp
= temp_stack
.reg
[k
];
1937 temp_stack
.reg
[k
] = temp_stack
.reg
[j
];
1938 temp_stack
.reg
[j
] = temp
;
1942 /* Emit insns before INSN to make sure the reg-stack is in the right
1945 change_stack (insn
, regstack
, &temp_stack
, EMIT_BEFORE
);
1947 /* Make the needed input register substitutions. Do death notes and
1948 clobbers too, because these are for inputs, not outputs. */
1950 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
1951 if (STACK_REG_P (recog_data
.operand
[i
]))
1953 int regnum
= get_hard_regnum (regstack
, recog_data
.operand
[i
]);
1958 replace_reg (recog_data
.operand_loc
[i
], regnum
);
1961 for (i
= 0; i
< n_notes
; i
++)
1962 if (note_kind
[i
] == REG_DEAD
)
1964 int regnum
= get_hard_regnum (regstack
, note_reg
[i
]);
1969 replace_reg (note_loc
[i
], regnum
);
1972 for (i
= 0; i
< n_clobbers
; i
++)
1974 /* It's OK for a CLOBBER to reference a reg that is not live.
1975 Don't try to replace it in that case. */
1976 int regnum
= get_hard_regnum (regstack
, clobber_reg
[i
]);
1980 /* Sigh - clobbers always have QImode. But replace_reg knows
1981 that these regs can't be MODE_INT and will abort. Just put
1982 the right reg there without calling replace_reg. */
1984 *clobber_loc
[i
] = FP_MODE_REG (regnum
, DFmode
);
1988 /* Now remove from REGSTACK any inputs that the asm implicitly popped. */
1990 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
1991 if (STACK_REG_P (recog_data
.operand
[i
]))
1993 /* An input reg is implicitly popped if it is tied to an
1994 output, or if there is a CLOBBER for it. */
1997 for (j
= 0; j
< n_clobbers
; j
++)
1998 if (operands_match_p (clobber_reg
[j
], recog_data
.operand
[i
]))
2001 if (j
< n_clobbers
|| recog_op_alt
[i
][alt
].matches
>= 0)
2003 /* recog_data.operand[i] might not be at the top of stack.
2004 But that's OK, because all we need to do is pop the
2005 right number of regs off of the top of the reg-stack.
2006 record_asm_stack_regs guaranteed that all implicitly
2007 popped regs were grouped at the top of the reg-stack. */
2009 CLEAR_HARD_REG_BIT (regstack
->reg_set
,
2010 regstack
->reg
[regstack
->top
]);
2015 /* Now add to REGSTACK any outputs that the asm implicitly pushed.
2016 Note that there isn't any need to substitute register numbers.
2017 ??? Explain why this is true. */
2019 for (i
= LAST_STACK_REG
; i
>= FIRST_STACK_REG
; i
--)
2021 /* See if there is an output for this hard reg. */
2024 for (j
= 0; j
< n_outputs
; j
++)
2025 if (STACK_REG_P (recog_data
.operand
[j
])
2026 && REGNO (recog_data
.operand
[j
]) == i
)
2028 regstack
->reg
[++regstack
->top
] = i
;
2029 SET_HARD_REG_BIT (regstack
->reg_set
, i
);
2034 /* Now emit a pop insn for any REG_UNUSED output, or any REG_DEAD
2035 input that the asm didn't implicitly pop. If the asm didn't
2036 implicitly pop an input reg, that reg will still be live.
2038 Note that we can't use find_regno_note here: the register numbers
2039 in the death notes have already been substituted. */
2041 for (i
= 0; i
< n_outputs
; i
++)
2042 if (STACK_REG_P (recog_data
.operand
[i
]))
2046 for (j
= 0; j
< n_notes
; j
++)
2047 if (REGNO (recog_data
.operand
[i
]) == REGNO (note_reg
[j
])
2048 && note_kind
[j
] == REG_UNUSED
)
2050 insn
= emit_pop_insn (insn
, regstack
, recog_data
.operand
[i
],
2056 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
2057 if (STACK_REG_P (recog_data
.operand
[i
]))
2061 for (j
= 0; j
< n_notes
; j
++)
2062 if (REGNO (recog_data
.operand
[i
]) == REGNO (note_reg
[j
])
2063 && note_kind
[j
] == REG_DEAD
2064 && TEST_HARD_REG_BIT (regstack
->reg_set
,
2065 REGNO (recog_data
.operand
[i
])))
2067 insn
= emit_pop_insn (insn
, regstack
, recog_data
.operand
[i
],
2074 /* Substitute stack hard reg numbers for stack virtual registers in
2075 INSN. Non-stack register numbers are not changed. REGSTACK is the
2076 current stack content. Insns may be emitted as needed to arrange the
2077 stack for the 387 based on the contents of the insn. */
2080 subst_stack_regs (insn
, regstack
)
2084 register rtx
*note_link
, note
;
2087 if (GET_CODE (insn
) == CALL_INSN
)
2089 int top
= regstack
->top
;
2091 /* If there are any floating point parameters to be passed in
2092 registers for this call, make sure they are in the right
2097 straighten_stack (PREV_INSN (insn
), regstack
);
2099 /* Now mark the arguments as dead after the call. */
2101 while (regstack
->top
>= 0)
2103 CLEAR_HARD_REG_BIT (regstack
->reg_set
, FIRST_STACK_REG
+ regstack
->top
);
2109 /* Do the actual substitution if any stack regs are mentioned.
2110 Since we only record whether entire insn mentions stack regs, and
2111 subst_stack_regs_pat only works for patterns that contain stack regs,
2112 we must check each pattern in a parallel here. A call_value_pop could
2115 if (stack_regs_mentioned (insn
))
2117 int n_operands
= asm_noperands (PATTERN (insn
));
2118 if (n_operands
>= 0)
2120 /* This insn is an `asm' with operands. Decode the operands,
2121 decide how many are inputs, and do register substitution.
2122 Any REG_UNUSED notes will be handled by subst_asm_stack_regs. */
2124 subst_asm_stack_regs (insn
, regstack
);
2128 if (GET_CODE (PATTERN (insn
)) == PARALLEL
)
2129 for (i
= 0; i
< XVECLEN (PATTERN (insn
), 0); i
++)
2131 if (stack_regs_mentioned_p (XVECEXP (PATTERN (insn
), 0, i
)))
2132 subst_stack_regs_pat (insn
, regstack
,
2133 XVECEXP (PATTERN (insn
), 0, i
));
2136 subst_stack_regs_pat (insn
, regstack
, PATTERN (insn
));
2139 /* subst_stack_regs_pat may have deleted a no-op insn. If so, any
2140 REG_UNUSED will already have been dealt with, so just return. */
2142 if (GET_CODE (insn
) == NOTE
)
2145 /* If there is a REG_UNUSED note on a stack register on this insn,
2146 the indicated reg must be popped. The REG_UNUSED note is removed,
2147 since the form of the newly emitted pop insn references the reg,
2148 making it no longer `unset'. */
2150 note_link
= ®_NOTES(insn
);
2151 for (note
= *note_link
; note
; note
= XEXP (note
, 1))
2152 if (REG_NOTE_KIND (note
) == REG_UNUSED
&& STACK_REG_P (XEXP (note
, 0)))
2154 *note_link
= XEXP (note
, 1);
2155 insn
= emit_pop_insn (insn
, regstack
, XEXP (note
, 0), EMIT_AFTER
);
2158 note_link
= &XEXP (note
, 1);
2161 /* Change the organization of the stack so that it fits a new basic
2162 block. Some registers might have to be popped, but there can never be
2163 a register live in the new block that is not now live.
2165 Insert any needed insns before or after INSN, as indicated by
2166 WHERE. OLD is the original stack layout, and NEW is the desired
2167 form. OLD is updated to reflect the code emitted, ie, it will be
2168 the same as NEW upon return.
2170 This function will not preserve block_end[]. But that information
2171 is no longer needed once this has executed. */
2174 change_stack (insn
, old
, new, where
)
2178 enum emit_where where
;
2183 /* We will be inserting new insns "backwards". If we are to insert
2184 after INSN, find the next insn, and insert before it. */
2186 if (where
== EMIT_AFTER
)
2188 if (current_block
&& current_block
->end
== insn
)
2190 insn
= NEXT_INSN (insn
);
2193 /* Pop any registers that are not needed in the new block. */
2195 for (reg
= old
->top
; reg
>= 0; reg
--)
2196 if (! TEST_HARD_REG_BIT (new->reg_set
, old
->reg
[reg
]))
2197 emit_pop_insn (insn
, old
, FP_MODE_REG (old
->reg
[reg
], DFmode
),
2202 /* If the new block has never been processed, then it can inherit
2203 the old stack order. */
2205 new->top
= old
->top
;
2206 memcpy (new->reg
, old
->reg
, sizeof (new->reg
));
2210 /* This block has been entered before, and we must match the
2211 previously selected stack order. */
2213 /* By now, the only difference should be the order of the stack,
2214 not their depth or liveliness. */
2216 GO_IF_HARD_REG_EQUAL (old
->reg_set
, new->reg_set
, win
);
2219 if (old
->top
!= new->top
)
2222 /* If the stack is not empty (new->top != -1), loop here emitting
2223 swaps until the stack is correct.
2225 The worst case number of swaps emitted is N + 2, where N is the
2226 depth of the stack. In some cases, the reg at the top of
2227 stack may be correct, but swapped anyway in order to fix
2228 other regs. But since we never swap any other reg away from
2229 its correct slot, this algorithm will converge. */
2234 /* Swap the reg at top of stack into the position it is
2235 supposed to be in, until the correct top of stack appears. */
2237 while (old
->reg
[old
->top
] != new->reg
[new->top
])
2239 for (reg
= new->top
; reg
>= 0; reg
--)
2240 if (new->reg
[reg
] == old
->reg
[old
->top
])
2246 emit_swap_insn (insn
, old
,
2247 FP_MODE_REG (old
->reg
[reg
], DFmode
));
2250 /* See if any regs remain incorrect. If so, bring an
2251 incorrect reg to the top of stack, and let the while loop
2254 for (reg
= new->top
; reg
>= 0; reg
--)
2255 if (new->reg
[reg
] != old
->reg
[reg
])
2257 emit_swap_insn (insn
, old
,
2258 FP_MODE_REG (old
->reg
[reg
], DFmode
));
2263 /* At this point there must be no differences. */
2265 for (reg
= old
->top
; reg
>= 0; reg
--)
2266 if (old
->reg
[reg
] != new->reg
[reg
])
2271 current_block
->end
= PREV_INSN (insn
);
2274 /* Print stack configuration. */
2277 print_stack (file
, s
)
2285 fprintf (file
, "uninitialized\n");
2286 else if (s
->top
== -1)
2287 fprintf (file
, "empty\n");
2292 for (i
= 0; i
<= s
->top
; ++i
)
2293 fprintf (file
, "%d ", s
->reg
[i
]);
2294 fputs ("]\n", file
);
2298 /* This function was doing life analysis. We now let the regular live
2299 code do it's job, so we only need to check some extra invariants
2300 that reg-stack expects. Primary among these being that all registers
2301 are initialized before use.
2303 The function returns true when code was emitted to CFG edges and
2304 commit_edge_insertions needs to be called. */
2307 convert_regs_entry ()
2309 int inserted
= 0, i
;
2312 for (i
= n_basic_blocks
- 1; i
>= 0; --i
)
2314 basic_block block
= BASIC_BLOCK (i
);
2315 block_info bi
= BLOCK_INFO (block
);
2318 /* Set current register status at last instruction `uninitialized'. */
2319 bi
->stack_in
.top
= -2;
2321 /* Copy live_at_end and live_at_start into temporaries. */
2322 for (reg
= FIRST_STACK_REG
; reg
<= LAST_STACK_REG
; reg
++)
2324 if (REGNO_REG_SET_P (block
->global_live_at_end
, reg
))
2325 SET_HARD_REG_BIT (bi
->out_reg_set
, reg
);
2326 if (REGNO_REG_SET_P (block
->global_live_at_start
, reg
))
2327 SET_HARD_REG_BIT (bi
->stack_in
.reg_set
, reg
);
2331 /* Load something into each stack register live at function entry.
2332 Such live registers can be caused by uninitialized variables or
2333 functions not returning values on all paths. In order to keep
2334 the push/pop code happy, and to not scrog the register stack, we
2335 must put something in these registers. Use a QNaN.
2337 Note that we are insertting converted code here. This code is
2338 never seen by the convert_regs pass. */
2340 for (e
= ENTRY_BLOCK_PTR
->succ
; e
; e
= e
->succ_next
)
2342 basic_block block
= e
->dest
;
2343 block_info bi
= BLOCK_INFO (block
);
2346 for (reg
= LAST_STACK_REG
; reg
>= FIRST_STACK_REG
; --reg
)
2347 if (TEST_HARD_REG_BIT (bi
->stack_in
.reg_set
, reg
))
2351 bi
->stack_in
.reg
[++top
] = reg
;
2353 init
= gen_rtx_SET (VOIDmode
,
2354 FP_MODE_REG (FIRST_STACK_REG
, SFmode
),
2356 insert_insn_on_edge (init
, e
);
2360 bi
->stack_in
.top
= top
;
2366 /* Construct the desired stack for function exit. This will either
2367 be `empty', or the function return value at top-of-stack. */
2370 convert_regs_exit ()
2372 int value_reg_low
, value_reg_high
;
2376 retvalue
= stack_result (current_function_decl
);
2377 value_reg_low
= value_reg_high
= -1;
2380 value_reg_low
= REGNO (retvalue
);
2381 value_reg_high
= value_reg_low
2382 + HARD_REGNO_NREGS (value_reg_low
, GET_MODE (retvalue
)) - 1;
2385 output_stack
= &BLOCK_INFO (EXIT_BLOCK_PTR
)->stack_in
;
2386 if (value_reg_low
== -1)
2387 output_stack
->top
= -1;
2392 output_stack
->top
= value_reg_high
- value_reg_low
;
2393 for (reg
= value_reg_low
; reg
<= value_reg_high
; ++reg
)
2395 output_stack
->reg
[reg
- value_reg_low
] = reg
;
2396 SET_HARD_REG_BIT (output_stack
->reg_set
, reg
);
2401 /* Convert stack register references in one block. */
2404 convert_regs_1 (file
, block
)
2408 struct stack_def regstack
, tmpstack
;
2409 block_info bi
= BLOCK_INFO (block
);
2414 current_block
= block
;
2418 fprintf (file
, "\nBasic block %d\nInput stack: ", block
->index
);
2419 print_stack (file
, &bi
->stack_in
);
2422 /* Process all insns in this block. Keep track of NEXT so that we
2423 don't process insns emitted while substituting in INSN. */
2425 regstack
= bi
->stack_in
;
2429 next
= NEXT_INSN (insn
);
2431 /* Ensure we have not missed a block boundary. */
2434 if (insn
== block
->end
)
2437 /* Don't bother processing unless there is a stack reg
2438 mentioned or if it's a CALL_INSN. */
2439 if (stack_regs_mentioned (insn
)
2440 || GET_CODE (insn
) == CALL_INSN
)
2444 fprintf (file
, " insn %d input stack: ",
2446 print_stack (file
, ®stack
);
2448 subst_stack_regs (insn
, ®stack
);
2455 fprintf (file
, "Expected live registers [");
2456 for (reg
= FIRST_STACK_REG
; reg
<= LAST_STACK_REG
; ++reg
)
2457 if (TEST_HARD_REG_BIT (bi
->out_reg_set
, reg
))
2458 fprintf (file
, " %d", reg
);
2459 fprintf (file
, " ]\nOutput stack: ");
2460 print_stack (file
, ®stack
);
2464 if (GET_CODE (insn
) == JUMP_INSN
)
2465 insn
= PREV_INSN (insn
);
2467 /* If the function is declared to return a value, but it returns one
2468 in only some cases, some registers might come live here. Emit
2469 necessary moves for them. */
2471 for (reg
= FIRST_STACK_REG
; reg
<= LAST_STACK_REG
; ++reg
)
2473 if (TEST_HARD_REG_BIT (bi
->out_reg_set
, reg
)
2474 && ! TEST_HARD_REG_BIT (regstack
.reg_set
, reg
))
2480 fprintf (file
, "Emitting insn initializing reg %d\n",
2484 set
= gen_rtx_SET (VOIDmode
, FP_MODE_REG (reg
, SFmode
),
2486 insn
= emit_block_insn_after (set
, insn
, block
);
2487 subst_stack_regs (insn
, ®stack
);
2491 /* Something failed if the stack lives don't match. */
2492 GO_IF_HARD_REG_EQUAL (regstack
.reg_set
, bi
->out_reg_set
, win
);
2496 /* Adjust the stack of this block on exit to match the stack of the
2497 target block, or copy stack info into the stack of the successor
2498 of the successor hasn't been processed yet. */
2500 for (e
= block
->succ
; e
; e
= e
->succ_next
)
2502 basic_block target
= e
->dest
;
2503 stack target_stack
= &BLOCK_INFO (target
)->stack_in
;
2506 fprintf (file
, "Edge to block %d: ", target
->index
);
2508 if (target_stack
->top
== -2)
2510 /* The target block hasn't had a stack order selected.
2511 We need merely ensure that no pops are needed. */
2512 for (reg
= regstack
.top
; reg
>= 0; --reg
)
2513 if (! TEST_HARD_REG_BIT (target_stack
->reg_set
,
2520 fprintf (file
, "new block; copying stack position\n");
2522 /* change_stack kills values in regstack. */
2523 tmpstack
= regstack
;
2525 change_stack (block
->end
, &tmpstack
,
2526 target_stack
, EMIT_AFTER
);
2531 fprintf (file
, "new block; pops needed\n");
2535 if (target_stack
->top
== regstack
.top
)
2537 for (reg
= target_stack
->top
; reg
>= 0; --reg
)
2538 if (target_stack
->reg
[reg
] != regstack
.reg
[reg
])
2544 fprintf (file
, "no changes needed\n");
2551 fprintf (file
, "correcting stack to ");
2552 print_stack (file
, target_stack
);
2556 /* Care for EH edges specially. The normal return path may return
2557 a value in st(0), but the EH path will not, and there's no need
2558 to add popping code to the edge. */
2559 if (e
->flags
& (EDGE_EH
| EDGE_ABNORMAL_CALL
))
2561 /* Assert that the lifetimes are as we expect -- one value
2562 live at st(0) on the end of the source block, and no
2563 values live at the beginning of the destination block. */
2566 CLEAR_HARD_REG_SET (tmp
);
2567 GO_IF_HARD_REG_EQUAL (target_stack
->reg_set
, tmp
, eh1
);
2571 SET_HARD_REG_BIT (tmp
, FIRST_STACK_REG
);
2572 GO_IF_HARD_REG_EQUAL (regstack
.reg_set
, tmp
, eh2
);
2576 target_stack
->top
= -1;
2579 /* It is better to output directly to the end of the block
2580 instead of to the edge, because emit_swap can do minimal
2581 insn scheduling. We can do this when there is only one
2582 edge out, and it is not abnormal. */
2583 else if (block
->succ
->succ_next
== NULL
2584 && ! (e
->flags
& EDGE_ABNORMAL
))
2586 /* change_stack kills values in regstack. */
2587 tmpstack
= regstack
;
2589 change_stack (block
->end
, &tmpstack
, target_stack
,
2590 (GET_CODE (block
->end
) == JUMP_INSN
2591 ? EMIT_BEFORE
: EMIT_AFTER
));
2597 /* We don't support abnormal edges. Global takes care to
2598 avoid any live register across them, so we should never
2599 have to insert instructions on such edges. */
2600 if (e
->flags
& EDGE_ABNORMAL
)
2603 current_block
= NULL
;
2606 /* ??? change_stack needs some point to emit insns after.
2607 Also needed to keep gen_sequence from returning a
2608 pattern as opposed to a sequence, which would lose
2610 after
= emit_note (NULL
, NOTE_INSN_DELETED
);
2612 tmpstack
= regstack
;
2613 change_stack (after
, &tmpstack
, target_stack
, EMIT_BEFORE
);
2615 seq
= gen_sequence ();
2618 insert_insn_on_edge (seq
, e
);
2620 current_block
= block
;
2627 /* Convert registers in all blocks reachable from BLOCK. */
2630 convert_regs_2 (file
, block
)
2634 basic_block
*stack
, *sp
;
2637 stack
= (basic_block
*) xmalloc (sizeof (*stack
) * n_basic_blocks
);
2641 BLOCK_INFO (block
)->done
= 1;
2649 inserted
|= convert_regs_1 (file
, block
);
2651 for (e
= block
->succ
; e
; e
= e
->succ_next
)
2652 if (! BLOCK_INFO (e
->dest
)->done
)
2655 BLOCK_INFO (e
->dest
)->done
= 1;
2658 while (sp
!= stack
);
2663 /* Traverse all basic blocks in a function, converting the register
2664 references in each insn from the "flat" register file that gcc uses,
2665 to the stack-like registers the 387 uses. */
2674 /* Initialize uninitialized registers on function entry. */
2675 inserted
= convert_regs_entry ();
2677 /* Construct the desired stack for function exit. */
2678 convert_regs_exit ();
2679 BLOCK_INFO (EXIT_BLOCK_PTR
)->done
= 1;
2681 /* ??? Future: process inner loops first, and give them arbitrary
2682 initial stacks which emit_swap_insn can modify. This ought to
2683 prevent double fxch that aften appears at the head of a loop. */
2685 /* Process all blocks reachable from all entry points. */
2686 for (e
= ENTRY_BLOCK_PTR
->succ
; e
; e
= e
->succ_next
)
2687 inserted
|= convert_regs_2 (file
, e
->dest
);
2689 /* ??? Process all unreachable blocks. Though there's no excuse
2690 for keeping these even when not optimizing. */
2691 for (i
= 0; i
< n_basic_blocks
; ++i
)
2693 basic_block b
= BASIC_BLOCK (i
);
2694 block_info bi
= BLOCK_INFO (b
);
2700 /* Create an arbitrary input stack. */
2701 bi
->stack_in
.top
= -1;
2702 for (reg
= LAST_STACK_REG
; reg
>= FIRST_STACK_REG
; --reg
)
2703 if (TEST_HARD_REG_BIT (bi
->stack_in
.reg_set
, reg
))
2704 bi
->stack_in
.reg
[++bi
->stack_in
.top
] = reg
;
2706 inserted
|= convert_regs_2 (file
, b
);
2711 commit_edge_insertions ();
2718 #endif /* STACK_REGS */