1 /* Register to Stack convert for GNU compiler.
2 Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000 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
;
305 if (GET_RTX_CLASS (GET_CODE (insn
)) != 'i')
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. */
337 /* ??? This really cries for BLOCK_END! */
341 insn
= NEXT_INSN (insn
);
345 if (GET_RTX_CLASS (GET_CODE (insn
)) == 'i'
346 && reg_mentioned_p (ix86_flags_rtx
, PATTERN (insn
)))
349 if (GET_CODE (insn
) == JUMP_INSN
350 || GET_CODE (insn
) == CODE_LABEL
351 || GET_CODE (insn
) == CALL_INSN
)
356 /* Reorganise the stack into ascending numbers,
360 straighten_stack (insn
, regstack
)
364 struct stack_def temp_stack
;
367 /* If there is only a single register on the stack, then the stack is
368 already in increasing order and no reorganization is needed.
370 Similarly if the stack is empty. */
371 if (regstack
->top
<= 0)
374 COPY_HARD_REG_SET (temp_stack
.reg_set
, regstack
->reg_set
);
376 for (top
= temp_stack
.top
= regstack
->top
; top
>= 0; top
--)
377 temp_stack
.reg
[top
] = FIRST_STACK_REG
+ temp_stack
.top
- top
;
379 change_stack (insn
, regstack
, &temp_stack
, EMIT_AFTER
);
382 /* Pop a register from the stack */
385 pop_stack (regstack
, regno
)
389 int top
= regstack
->top
;
391 CLEAR_HARD_REG_BIT (regstack
->reg_set
, regno
);
393 /* If regno was not at the top of stack then adjust stack */
394 if (regstack
->reg
[top
] != regno
)
397 for (i
= regstack
->top
; i
>= 0; i
--)
398 if (regstack
->reg
[i
] == regno
)
401 for (j
= i
; j
< top
; j
++)
402 regstack
->reg
[j
] = regstack
->reg
[j
+ 1];
408 /* Convert register usage from "flat" register file usage to a "stack
409 register file. FIRST is the first insn in the function, FILE is the
412 Construct a CFG and run life analysis. Then convert each insn one
413 by one. Run a last jump_optimize pass, if optimizing, to eliminate
414 code duplication created when the converter inserts pop insns on
418 reg_to_stack (first
, file
)
426 /* See if there is something to do. Flow analysis is quite
427 expensive so we might save some compilation time. */
428 for (i
= FIRST_STACK_REG
; i
<= LAST_STACK_REG
; i
++)
429 if (regs_ever_live
[i
])
431 if (i
> LAST_STACK_REG
)
434 /* Ok, floating point instructions exist. If not optimizing,
435 build the CFG and run life analysis. */
436 find_basic_blocks (first
, max_reg_num (), file
);
437 count_or_remove_death_notes (NULL
, 1);
438 life_analysis (first
, file
, PROP_DEATH_NOTES
);
440 /* Set up block info for each basic block. */
441 bi
= (block_info
) xcalloc ((n_basic_blocks
+ 1), sizeof (*bi
));
442 for (i
= n_basic_blocks
- 1; i
>= 0; --i
)
443 BASIC_BLOCK (i
)->aux
= bi
+ i
;
444 EXIT_BLOCK_PTR
->aux
= bi
+ n_basic_blocks
;
446 /* Create the replacement registers up front. */
447 for (i
= FIRST_STACK_REG
; i
<= LAST_STACK_REG
; i
++)
449 enum machine_mode mode
;
450 for (mode
= GET_CLASS_NARROWEST_MODE (MODE_FLOAT
);
452 mode
= GET_MODE_WIDER_MODE (mode
))
453 FP_MODE_REG (i
, mode
) = gen_rtx_REG (mode
, i
);
454 for (mode
= GET_CLASS_NARROWEST_MODE (MODE_COMPLEX_FLOAT
);
456 mode
= GET_MODE_WIDER_MODE (mode
))
457 FP_MODE_REG (i
, mode
) = gen_rtx_REG (mode
, i
);
460 ix86_flags_rtx
= gen_rtx_REG (CCmode
, FLAGS_REG
);
462 /* A QNaN for initializing uninitialized variables.
464 ??? We can't load from constant memory in PIC mode, because
465 we're insertting these instructions before the prologue and
466 the PIC register hasn't been set up. In that case, fall back
467 on zero, which we can get from `ldz'. */
470 nan
= CONST0_RTX (SFmode
);
473 nan
= gen_lowpart (SFmode
, GEN_INT (0x7fc00000));
474 nan
= force_const_mem (SFmode
, nan
);
477 /* Allocate a cache for stack_regs_mentioned. */
478 max_uid
= get_max_uid ();
479 VARRAY_CHAR_INIT (stack_regs_mentioned_data
, max_uid
+ 1,
480 "stack_regs_mentioned cache");
482 if (convert_regs (file
) && optimize
)
484 jump_optimize (first
, JUMP_CROSS_JUMP_DEATH_MATTERS
,
485 !JUMP_NOOP_MOVES
, !JUMP_AFTER_REGSCAN
);
489 VARRAY_FREE (stack_regs_mentioned_data
);
493 /* Check PAT, which is in INSN, for LABEL_REFs. Add INSN to the
494 label's chain of references, and note which insn contains each
498 record_label_references (insn
, pat
)
501 register enum rtx_code code
= GET_CODE (pat
);
503 register const char *fmt
;
505 if (code
== LABEL_REF
)
507 register rtx label
= XEXP (pat
, 0);
510 if (GET_CODE (label
) != CODE_LABEL
)
513 /* If this is an undefined label, LABEL_REFS (label) contains
515 if (INSN_UID (label
) == 0)
518 /* Don't make a duplicate in the code_label's chain. */
520 for (ref
= LABEL_REFS (label
);
522 ref
= LABEL_NEXTREF (ref
))
523 if (CONTAINING_INSN (ref
) == insn
)
526 CONTAINING_INSN (pat
) = insn
;
527 LABEL_NEXTREF (pat
) = LABEL_REFS (label
);
528 LABEL_REFS (label
) = pat
;
533 fmt
= GET_RTX_FORMAT (code
);
534 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
537 record_label_references (insn
, XEXP (pat
, i
));
541 for (j
= 0; j
< XVECLEN (pat
, i
); j
++)
542 record_label_references (insn
, XVECEXP (pat
, i
, j
));
547 /* Return a pointer to the REG expression within PAT. If PAT is not a
548 REG, possible enclosed by a conversion rtx, return the inner part of
549 PAT that stopped the search. */
556 switch (GET_CODE (*pat
))
559 /* Eliminate FP subregister accesses in favour of the
560 actual FP register in use. */
563 if (FP_REG_P (subreg
= SUBREG_REG (*pat
)))
565 *pat
= FP_MODE_REG (REGNO (subreg
) + SUBREG_WORD (*pat
),
574 pat
= & XEXP (*pat
, 0);
578 /* There are many rules that an asm statement for stack-like regs must
579 follow. Those rules are explained at the top of this file: the rule
580 numbers below refer to that explanation. */
583 check_asm_stack_operands (insn
)
588 int malformed_asm
= 0;
589 rtx body
= PATTERN (insn
);
591 char reg_used_as_output
[FIRST_PSEUDO_REGISTER
];
592 char implicitly_dies
[FIRST_PSEUDO_REGISTER
];
595 rtx
*clobber_reg
= 0;
596 int n_inputs
, n_outputs
;
598 /* Find out what the constraints require. If no constraint
599 alternative matches, this asm is malformed. */
601 constrain_operands (1);
602 alt
= which_alternative
;
604 preprocess_constraints ();
606 n_inputs
= get_asm_operand_n_inputs (body
);
607 n_outputs
= recog_data
.n_operands
- n_inputs
;
612 /* Avoid further trouble with this insn. */
613 PATTERN (insn
) = gen_rtx_USE (VOIDmode
, const0_rtx
);
617 /* Strip SUBREGs here to make the following code simpler. */
618 for (i
= 0; i
< recog_data
.n_operands
; i
++)
619 if (GET_CODE (recog_data
.operand
[i
]) == SUBREG
620 && GET_CODE (SUBREG_REG (recog_data
.operand
[i
])) == REG
)
621 recog_data
.operand
[i
] = SUBREG_REG (recog_data
.operand
[i
]);
623 /* Set up CLOBBER_REG. */
627 if (GET_CODE (body
) == PARALLEL
)
629 clobber_reg
= (rtx
*) alloca (XVECLEN (body
, 0) * sizeof (rtx
));
631 for (i
= 0; i
< XVECLEN (body
, 0); i
++)
632 if (GET_CODE (XVECEXP (body
, 0, i
)) == CLOBBER
)
634 rtx clobber
= XVECEXP (body
, 0, i
);
635 rtx reg
= XEXP (clobber
, 0);
637 if (GET_CODE (reg
) == SUBREG
&& GET_CODE (SUBREG_REG (reg
)) == REG
)
638 reg
= SUBREG_REG (reg
);
640 if (STACK_REG_P (reg
))
642 clobber_reg
[n_clobbers
] = reg
;
648 /* Enforce rule #4: Output operands must specifically indicate which
649 reg an output appears in after an asm. "=f" is not allowed: the
650 operand constraints must select a class with a single reg.
652 Also enforce rule #5: Output operands must start at the top of
653 the reg-stack: output operands may not "skip" a reg. */
655 memset (reg_used_as_output
, 0, sizeof (reg_used_as_output
));
656 for (i
= 0; i
< n_outputs
; i
++)
657 if (STACK_REG_P (recog_data
.operand
[i
]))
659 if (reg_class_size
[(int) recog_op_alt
[i
][alt
].class] != 1)
661 error_for_asm (insn
, "Output constraint %d must specify a single register", i
);
665 reg_used_as_output
[REGNO (recog_data
.operand
[i
])] = 1;
669 /* Search for first non-popped reg. */
670 for (i
= FIRST_STACK_REG
; i
< LAST_STACK_REG
+ 1; i
++)
671 if (! reg_used_as_output
[i
])
674 /* If there are any other popped regs, that's an error. */
675 for (; i
< LAST_STACK_REG
+ 1; i
++)
676 if (reg_used_as_output
[i
])
679 if (i
!= LAST_STACK_REG
+ 1)
681 error_for_asm (insn
, "Output regs must be grouped at top of stack");
685 /* Enforce rule #2: All implicitly popped input regs must be closer
686 to the top of the reg-stack than any input that is not implicitly
689 memset (implicitly_dies
, 0, sizeof (implicitly_dies
));
690 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
691 if (STACK_REG_P (recog_data
.operand
[i
]))
693 /* An input reg is implicitly popped if it is tied to an
694 output, or if there is a CLOBBER for it. */
697 for (j
= 0; j
< n_clobbers
; j
++)
698 if (operands_match_p (clobber_reg
[j
], recog_data
.operand
[i
]))
701 if (j
< n_clobbers
|| recog_op_alt
[i
][alt
].matches
>= 0)
702 implicitly_dies
[REGNO (recog_data
.operand
[i
])] = 1;
705 /* Search for first non-popped reg. */
706 for (i
= FIRST_STACK_REG
; i
< LAST_STACK_REG
+ 1; i
++)
707 if (! implicitly_dies
[i
])
710 /* If there are any other popped regs, that's an error. */
711 for (; i
< LAST_STACK_REG
+ 1; i
++)
712 if (implicitly_dies
[i
])
715 if (i
!= LAST_STACK_REG
+ 1)
718 "Implicitly popped regs must be grouped at top of stack");
722 /* Enfore rule #3: If any input operand uses the "f" constraint, all
723 output constraints must use the "&" earlyclobber.
725 ??? Detect this more deterministically by having constrain_asm_operands
726 record any earlyclobber. */
728 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
729 if (recog_op_alt
[i
][alt
].matches
== -1)
733 for (j
= 0; j
< n_outputs
; j
++)
734 if (operands_match_p (recog_data
.operand
[j
], recog_data
.operand
[i
]))
737 "Output operand %d must use `&' constraint", j
);
744 /* Avoid further trouble with this insn. */
745 PATTERN (insn
) = gen_rtx_USE (VOIDmode
, const0_rtx
);
752 /* Calculate the number of inputs and outputs in BODY, an
753 asm_operands. N_OPERANDS is the total number of operands, and
754 N_INPUTS and N_OUTPUTS are pointers to ints into which the results are
758 get_asm_operand_n_inputs (body
)
761 if (GET_CODE (body
) == SET
&& GET_CODE (SET_SRC (body
)) == ASM_OPERANDS
)
762 return ASM_OPERANDS_INPUT_LENGTH (SET_SRC (body
));
764 else if (GET_CODE (body
) == ASM_OPERANDS
)
765 return ASM_OPERANDS_INPUT_LENGTH (body
);
767 else if (GET_CODE (body
) == PARALLEL
768 && GET_CODE (XVECEXP (body
, 0, 0)) == SET
)
769 return ASM_OPERANDS_INPUT_LENGTH (SET_SRC (XVECEXP (body
, 0, 0)));
771 else if (GET_CODE (body
) == PARALLEL
772 && GET_CODE (XVECEXP (body
, 0, 0)) == ASM_OPERANDS
)
773 return ASM_OPERANDS_INPUT_LENGTH (XVECEXP (body
, 0, 0));
778 /* If current function returns its result in an fp stack register,
779 return the REG. Otherwise, return 0. */
787 /* If the value is supposed to be returned in memory, then clearly
788 it is not returned in a stack register. */
789 if (aggregate_value_p (DECL_RESULT (decl
)))
792 result
= DECL_RTL (DECL_RESULT (decl
));
793 /* ?!? What is this code supposed to do? Can this code actually
794 trigger if we kick out aggregates above? */
796 && ! (GET_CODE (result
) == REG
797 && REGNO (result
) < FIRST_PSEUDO_REGISTER
))
799 #ifdef FUNCTION_OUTGOING_VALUE
801 = FUNCTION_OUTGOING_VALUE (TREE_TYPE (DECL_RESULT (decl
)), decl
);
803 result
= FUNCTION_VALUE (TREE_TYPE (DECL_RESULT (decl
)), decl
);
807 return result
!= 0 && STACK_REG_P (result
) ? result
: 0;
812 * This section deals with stack register substitution, and forms the second
816 /* Replace REG, which is a pointer to a stack reg RTX, with an RTX for
817 the desired hard REGNO. */
820 replace_reg (reg
, regno
)
824 if (regno
< FIRST_STACK_REG
|| regno
> LAST_STACK_REG
825 || ! STACK_REG_P (*reg
))
828 switch (GET_MODE_CLASS (GET_MODE (*reg
)))
832 case MODE_COMPLEX_FLOAT
:;
835 *reg
= FP_MODE_REG (regno
, GET_MODE (*reg
));
838 /* Remove a note of type NOTE, which must be found, for register
839 number REGNO from INSN. Remove only one such note. */
842 remove_regno_note (insn
, note
, regno
)
847 register rtx
*note_link
, this;
849 note_link
= ®_NOTES(insn
);
850 for (this = *note_link
; this; this = XEXP (this, 1))
851 if (REG_NOTE_KIND (this) == note
852 && REG_P (XEXP (this, 0)) && REGNO (XEXP (this, 0)) == regno
)
854 *note_link
= XEXP (this, 1);
858 note_link
= &XEXP (this, 1);
863 /* Find the hard register number of virtual register REG in REGSTACK.
864 The hard register number is relative to the top of the stack. -1 is
865 returned if the register is not found. */
868 get_hard_regnum (regstack
, reg
)
874 if (! STACK_REG_P (reg
))
877 for (i
= regstack
->top
; i
>= 0; i
--)
878 if (regstack
->reg
[i
] == REGNO (reg
))
881 return i
>= 0 ? (FIRST_STACK_REG
+ regstack
->top
- i
) : -1;
884 /* Delete INSN from the RTL. Mark the insn, but don't remove it from
885 the chain of insns. Doing so could confuse block_begin and block_end
886 if this were the only insn in the block. */
889 delete_insn_for_stacker (insn
)
892 PUT_CODE (insn
, NOTE
);
893 NOTE_LINE_NUMBER (insn
) = NOTE_INSN_DELETED
;
894 NOTE_SOURCE_FILE (insn
) = 0;
897 /* Emit an insn to pop virtual register REG before or after INSN.
898 REGSTACK is the stack state after INSN and is updated to reflect this
899 pop. WHEN is either emit_insn_before or emit_insn_after. A pop insn
900 is represented as a SET whose destination is the register to be popped
901 and source is the top of stack. A death note for the top of stack
902 cases the movdf pattern to pop. */
905 emit_pop_insn (insn
, regstack
, reg
, where
)
909 enum emit_where where
;
911 rtx pop_insn
, pop_rtx
;
914 hard_regno
= get_hard_regnum (regstack
, reg
);
916 if (hard_regno
< FIRST_STACK_REG
)
919 pop_rtx
= gen_rtx_SET (VOIDmode
, FP_MODE_REG (hard_regno
, DFmode
),
920 FP_MODE_REG (FIRST_STACK_REG
, DFmode
));
922 if (where
== EMIT_AFTER
)
923 pop_insn
= emit_block_insn_after (pop_rtx
, insn
, current_block
);
925 pop_insn
= emit_block_insn_before (pop_rtx
, insn
, current_block
);
928 = gen_rtx_EXPR_LIST (REG_DEAD
, FP_MODE_REG (FIRST_STACK_REG
, DFmode
),
929 REG_NOTES (pop_insn
));
931 regstack
->reg
[regstack
->top
- (hard_regno
- FIRST_STACK_REG
)]
932 = regstack
->reg
[regstack
->top
];
934 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (reg
));
939 /* Emit an insn before or after INSN to swap virtual register REG with
940 the top of stack. REGSTACK is the stack state before the swap, and
941 is updated to reflect the swap. A swap insn is represented as a
942 PARALLEL of two patterns: each pattern moves one reg to the other.
944 If REG is already at the top of the stack, no insn is emitted. */
947 emit_swap_insn (insn
, regstack
, reg
)
954 int tmp
, other_reg
; /* swap regno temps */
955 rtx i1
; /* the stack-reg insn prior to INSN */
956 rtx i1set
= NULL_RTX
; /* the SET rtx within I1 */
958 hard_regno
= get_hard_regnum (regstack
, reg
);
960 if (hard_regno
< FIRST_STACK_REG
)
962 if (hard_regno
== FIRST_STACK_REG
)
965 other_reg
= regstack
->top
- (hard_regno
- FIRST_STACK_REG
);
967 tmp
= regstack
->reg
[other_reg
];
968 regstack
->reg
[other_reg
] = regstack
->reg
[regstack
->top
];
969 regstack
->reg
[regstack
->top
] = tmp
;
971 /* Find the previous insn involving stack regs, but don't pass a
974 if (current_block
&& insn
!= current_block
->head
)
976 rtx tmp
= PREV_INSN (insn
);
977 rtx limit
= PREV_INSN (current_block
->head
);
980 if (GET_CODE (tmp
) == CODE_LABEL
981 || (GET_CODE (tmp
) == NOTE
982 && NOTE_LINE_NUMBER (tmp
) == NOTE_INSN_BASIC_BLOCK
)
983 || (GET_CODE (tmp
) == INSN
984 && stack_regs_mentioned (tmp
)))
989 tmp
= PREV_INSN (tmp
);
994 && (i1set
= single_set (i1
)) != NULL_RTX
)
996 rtx i1src
= *get_true_reg (&SET_SRC (i1set
));
997 rtx i1dest
= *get_true_reg (&SET_DEST (i1set
));
999 /* If the previous register stack push was from the reg we are to
1000 swap with, omit the swap. */
1002 if (GET_CODE (i1dest
) == REG
&& REGNO (i1dest
) == FIRST_STACK_REG
1003 && GET_CODE (i1src
) == REG
&& REGNO (i1src
) == hard_regno
- 1
1004 && find_regno_note (i1
, REG_DEAD
, FIRST_STACK_REG
) == NULL_RTX
)
1007 /* If the previous insn wrote to the reg we are to swap with,
1010 if (GET_CODE (i1dest
) == REG
&& REGNO (i1dest
) == hard_regno
1011 && GET_CODE (i1src
) == REG
&& REGNO (i1src
) == FIRST_STACK_REG
1012 && find_regno_note (i1
, REG_DEAD
, FIRST_STACK_REG
) == NULL_RTX
)
1016 swap_rtx
= gen_swapxf (FP_MODE_REG (hard_regno
, XFmode
),
1017 FP_MODE_REG (FIRST_STACK_REG
, XFmode
));
1020 emit_block_insn_after (swap_rtx
, i1
, current_block
);
1021 else if (current_block
)
1022 emit_block_insn_before (swap_rtx
, current_block
->head
, current_block
);
1024 emit_insn_before (swap_rtx
, insn
);
1027 /* Handle a move to or from a stack register in PAT, which is in INSN.
1028 REGSTACK is the current stack. */
1031 move_for_stack_reg (insn
, regstack
, pat
)
1036 rtx
*psrc
= get_true_reg (&SET_SRC (pat
));
1037 rtx
*pdest
= get_true_reg (&SET_DEST (pat
));
1041 src
= *psrc
; dest
= *pdest
;
1043 if (STACK_REG_P (src
) && STACK_REG_P (dest
))
1045 /* Write from one stack reg to another. If SRC dies here, then
1046 just change the register mapping and delete the insn. */
1048 note
= find_regno_note (insn
, REG_DEAD
, REGNO (src
));
1053 /* If this is a no-op move, there must not be a REG_DEAD note. */
1054 if (REGNO (src
) == REGNO (dest
))
1057 for (i
= regstack
->top
; i
>= 0; i
--)
1058 if (regstack
->reg
[i
] == REGNO (src
))
1061 /* The source must be live, and the dest must be dead. */
1062 if (i
< 0 || get_hard_regnum (regstack
, dest
) >= FIRST_STACK_REG
)
1065 /* It is possible that the dest is unused after this insn.
1066 If so, just pop the src. */
1068 if (find_regno_note (insn
, REG_UNUSED
, REGNO (dest
)))
1070 emit_pop_insn (insn
, regstack
, src
, EMIT_AFTER
);
1072 delete_insn_for_stacker (insn
);
1076 regstack
->reg
[i
] = REGNO (dest
);
1078 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (dest
));
1079 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (src
));
1081 delete_insn_for_stacker (insn
);
1086 /* The source reg does not die. */
1088 /* If this appears to be a no-op move, delete it, or else it
1089 will confuse the machine description output patterns. But if
1090 it is REG_UNUSED, we must pop the reg now, as per-insn processing
1091 for REG_UNUSED will not work for deleted insns. */
1093 if (REGNO (src
) == REGNO (dest
))
1095 if (find_regno_note (insn
, REG_UNUSED
, REGNO (dest
)))
1096 emit_pop_insn (insn
, regstack
, dest
, EMIT_AFTER
);
1098 delete_insn_for_stacker (insn
);
1102 /* The destination ought to be dead */
1103 if (get_hard_regnum (regstack
, dest
) >= FIRST_STACK_REG
)
1106 replace_reg (psrc
, get_hard_regnum (regstack
, src
));
1108 regstack
->reg
[++regstack
->top
] = REGNO (dest
);
1109 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (dest
));
1110 replace_reg (pdest
, FIRST_STACK_REG
);
1112 else if (STACK_REG_P (src
))
1114 /* Save from a stack reg to MEM, or possibly integer reg. Since
1115 only top of stack may be saved, emit an exchange first if
1118 emit_swap_insn (insn
, regstack
, src
);
1120 note
= find_regno_note (insn
, REG_DEAD
, REGNO (src
));
1123 replace_reg (&XEXP (note
, 0), FIRST_STACK_REG
);
1125 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (src
));
1127 else if (GET_MODE (src
) == XFmode
&& regstack
->top
< REG_STACK_SIZE
- 1)
1129 /* A 387 cannot write an XFmode value to a MEM without
1130 clobbering the source reg. The output code can handle
1131 this by reading back the value from the MEM.
1132 But it is more efficient to use a temp register if one is
1133 available. Push the source value here if the register
1134 stack is not full, and then write the value to memory via
1136 rtx push_rtx
, push_insn
;
1137 rtx top_stack_reg
= FP_MODE_REG (FIRST_STACK_REG
, XFmode
);
1139 push_rtx
= gen_movxf (top_stack_reg
, top_stack_reg
);
1140 push_insn
= emit_insn_before (push_rtx
, insn
);
1141 REG_NOTES (insn
) = gen_rtx_EXPR_LIST (REG_DEAD
, top_stack_reg
,
1145 replace_reg (psrc
, FIRST_STACK_REG
);
1147 else if (STACK_REG_P (dest
))
1149 /* Load from MEM, or possibly integer REG or constant, into the
1150 stack regs. The actual target is always the top of the
1151 stack. The stack mapping is changed to reflect that DEST is
1152 now at top of stack. */
1154 /* The destination ought to be dead */
1155 if (get_hard_regnum (regstack
, dest
) >= FIRST_STACK_REG
)
1158 if (regstack
->top
>= REG_STACK_SIZE
)
1161 regstack
->reg
[++regstack
->top
] = REGNO (dest
);
1162 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (dest
));
1163 replace_reg (pdest
, FIRST_STACK_REG
);
1169 /* Swap the condition on a branch, if there is one. Return true if we
1170 found a condition to swap. False if the condition was not used as
1174 swap_rtx_condition_1 (pat
)
1177 register const char *fmt
;
1178 register int i
, r
= 0;
1180 if (GET_RTX_CLASS (GET_CODE (pat
)) == '<')
1182 PUT_CODE (pat
, swap_condition (GET_CODE (pat
)));
1187 fmt
= GET_RTX_FORMAT (GET_CODE (pat
));
1188 for (i
= GET_RTX_LENGTH (GET_CODE (pat
)) - 1; i
>= 0; i
--)
1194 for (j
= XVECLEN (pat
, i
) - 1; j
>= 0; j
--)
1195 r
|= swap_rtx_condition_1 (XVECEXP (pat
, i
, j
));
1197 else if (fmt
[i
] == 'e')
1198 r
|= swap_rtx_condition_1 (XEXP (pat
, i
));
1206 swap_rtx_condition (insn
)
1209 rtx pat
= PATTERN (insn
);
1211 /* We're looking for a single set to cc0 or an HImode temporary. */
1213 if (GET_CODE (pat
) == SET
1214 && GET_CODE (SET_DEST (pat
)) == REG
1215 && REGNO (SET_DEST (pat
)) == FLAGS_REG
)
1217 insn
= next_flags_user (insn
);
1218 if (insn
== NULL_RTX
)
1220 pat
= PATTERN (insn
);
1223 /* See if this is, or ends in, a fnstsw, aka unspec 9. If so, we're
1224 not doing anything with the cc value right now. We may be able to
1225 search for one though. */
1227 if (GET_CODE (pat
) == SET
1228 && GET_CODE (SET_SRC (pat
)) == UNSPEC
1229 && XINT (SET_SRC (pat
), 1) == 9)
1231 rtx dest
= SET_DEST (pat
);
1233 /* Search forward looking for the first use of this value.
1234 Stop at block boundaries. */
1235 /* ??? This really cries for BLOCK_END! */
1238 insn
= NEXT_INSN (insn
);
1239 if (insn
== NULL_RTX
)
1241 if (GET_RTX_CLASS (GET_CODE (insn
)) == 'i'
1242 && reg_mentioned_p (dest
, insn
))
1244 if (GET_CODE (insn
) == JUMP_INSN
)
1246 if (GET_CODE (insn
) == CODE_LABEL
)
1250 /* So we've found the insn using this value. If it is anything
1251 other than sahf, aka unspec 10, or the value does not die
1252 (meaning we'd have to search further), then we must give up. */
1253 pat
= PATTERN (insn
);
1254 if (GET_CODE (pat
) != SET
1255 || GET_CODE (SET_SRC (pat
)) != UNSPEC
1256 || XINT (SET_SRC (pat
), 1) != 10
1257 || ! dead_or_set_p (insn
, dest
))
1260 /* Now we are prepared to handle this as a normal cc0 setter. */
1261 insn
= next_flags_user (insn
);
1262 if (insn
== NULL_RTX
)
1264 pat
= PATTERN (insn
);
1267 return swap_rtx_condition_1 (pat
);
1270 /* Handle a comparison. Special care needs to be taken to avoid
1271 causing comparisons that a 387 cannot do correctly, such as EQ.
1273 Also, a pop insn may need to be emitted. The 387 does have an
1274 `fcompp' insn that can pop two regs, but it is sometimes too expensive
1275 to do this - a `fcomp' followed by a `fstpl %st(0)' may be easier to
1279 compare_for_stack_reg (insn
, regstack
, pat_src
)
1285 rtx src1_note
, src2_note
;
1288 src1
= get_true_reg (&XEXP (pat_src
, 0));
1289 src2
= get_true_reg (&XEXP (pat_src
, 1));
1290 flags_user
= next_flags_user (insn
);
1292 /* ??? If fxch turns out to be cheaper than fstp, give priority to
1293 registers that die in this insn - move those to stack top first. */
1294 if ((! STACK_REG_P (*src1
)
1295 || (STACK_REG_P (*src2
)
1296 && get_hard_regnum (regstack
, *src2
) == FIRST_STACK_REG
))
1297 && swap_rtx_condition (insn
))
1300 temp
= XEXP (pat_src
, 0);
1301 XEXP (pat_src
, 0) = XEXP (pat_src
, 1);
1302 XEXP (pat_src
, 1) = temp
;
1304 src1
= get_true_reg (&XEXP (pat_src
, 0));
1305 src2
= get_true_reg (&XEXP (pat_src
, 1));
1307 INSN_CODE (insn
) = -1;
1310 /* We will fix any death note later. */
1312 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1314 if (STACK_REG_P (*src2
))
1315 src2_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src2
));
1317 src2_note
= NULL_RTX
;
1319 emit_swap_insn (insn
, regstack
, *src1
);
1321 replace_reg (src1
, FIRST_STACK_REG
);
1323 if (STACK_REG_P (*src2
))
1324 replace_reg (src2
, get_hard_regnum (regstack
, *src2
));
1328 pop_stack (regstack
, REGNO (XEXP (src1_note
, 0)));
1329 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1332 /* If the second operand dies, handle that. But if the operands are
1333 the same stack register, don't bother, because only one death is
1334 needed, and it was just handled. */
1337 && ! (STACK_REG_P (*src1
) && STACK_REG_P (*src2
)
1338 && REGNO (*src1
) == REGNO (*src2
)))
1340 /* As a special case, two regs may die in this insn if src2 is
1341 next to top of stack and the top of stack also dies. Since
1342 we have already popped src1, "next to top of stack" is really
1343 at top (FIRST_STACK_REG) now. */
1345 if (get_hard_regnum (regstack
, XEXP (src2_note
, 0)) == FIRST_STACK_REG
1348 pop_stack (regstack
, REGNO (XEXP (src2_note
, 0)));
1349 replace_reg (&XEXP (src2_note
, 0), FIRST_STACK_REG
+ 1);
1353 /* The 386 can only represent death of the first operand in
1354 the case handled above. In all other cases, emit a separate
1355 pop and remove the death note from here. */
1357 /* link_cc0_insns (insn); */
1359 remove_regno_note (insn
, REG_DEAD
, REGNO (XEXP (src2_note
, 0)));
1361 emit_pop_insn (insn
, regstack
, XEXP (src2_note
, 0),
1367 /* Substitute new registers in PAT, which is part of INSN. REGSTACK
1368 is the current register layout. */
1371 subst_stack_regs_pat (insn
, regstack
, pat
)
1378 switch (GET_CODE (pat
))
1381 /* Deaths in USE insns can happen in non optimizing compilation.
1382 Handle them by popping the dying register. */
1383 src
= get_true_reg (&XEXP (pat
, 0));
1384 if (STACK_REG_P (*src
)
1385 && find_regno_note (insn
, REG_DEAD
, REGNO (*src
)))
1387 emit_pop_insn (insn
, regstack
, *src
, EMIT_AFTER
);
1390 /* ??? Uninitialized USE should not happen. */
1391 else if (get_hard_regnum (regstack
, *src
) == -1)
1399 dest
= get_true_reg (&XEXP (pat
, 0));
1400 if (STACK_REG_P (*dest
))
1402 note
= find_reg_note (insn
, REG_DEAD
, *dest
);
1404 if (pat
!= PATTERN (insn
))
1406 /* The fix_truncdi_1 pattern wants to be able to allocate
1407 it's own scratch register. It does this by clobbering
1408 an fp reg so that it is assured of an empty reg-stack
1409 register. If the register is live, kill it now.
1410 Remove the DEAD/UNUSED note so we don't try to kill it
1414 emit_pop_insn (insn
, regstack
, *dest
, EMIT_BEFORE
);
1417 note
= find_reg_note (insn
, REG_UNUSED
, *dest
);
1421 remove_note (insn
, note
);
1422 replace_reg (dest
, LAST_STACK_REG
);
1426 /* A top-level clobber with no REG_DEAD, and no hard-regnum
1427 indicates an uninitialized value. Because reload removed
1428 all other clobbers, this must be due to a function
1429 returning without a value. Load up a NaN. */
1432 && get_hard_regnum (regstack
, *dest
) == -1)
1434 pat
= gen_rtx_SET (VOIDmode
,
1435 FP_MODE_REG (REGNO (*dest
), SFmode
),
1437 PATTERN (insn
) = pat
;
1438 move_for_stack_reg (insn
, regstack
, pat
);
1447 rtx
*src1
= (rtx
*) NULL_PTR
, *src2
;
1448 rtx src1_note
, src2_note
;
1451 dest
= get_true_reg (&SET_DEST (pat
));
1452 src
= get_true_reg (&SET_SRC (pat
));
1453 pat_src
= SET_SRC (pat
);
1455 /* See if this is a `movM' pattern, and handle elsewhere if so. */
1456 if (STACK_REG_P (*src
)
1457 || (STACK_REG_P (*dest
)
1458 && (GET_CODE (*src
) == REG
|| GET_CODE (*src
) == MEM
1459 || GET_CODE (*src
) == CONST_DOUBLE
)))
1461 move_for_stack_reg (insn
, regstack
, pat
);
1465 switch (GET_CODE (pat_src
))
1468 compare_for_stack_reg (insn
, regstack
, pat_src
);
1474 for (count
= HARD_REGNO_NREGS (REGNO (*dest
), GET_MODE (*dest
));
1477 regstack
->reg
[++regstack
->top
] = REGNO (*dest
) + count
;
1478 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
) + count
);
1481 replace_reg (dest
, FIRST_STACK_REG
);
1485 /* This is a `tstM2' case. */
1486 if (*dest
!= cc0_rtx
)
1492 case FLOAT_TRUNCATE
:
1496 /* These insns only operate on the top of the stack. DEST might
1497 be cc0_rtx if we're processing a tstM pattern. Also, it's
1498 possible that the tstM case results in a REG_DEAD note on the
1502 src1
= get_true_reg (&XEXP (pat_src
, 0));
1504 emit_swap_insn (insn
, regstack
, *src1
);
1506 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1508 if (STACK_REG_P (*dest
))
1509 replace_reg (dest
, FIRST_STACK_REG
);
1513 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1515 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (*src1
));
1518 replace_reg (src1
, FIRST_STACK_REG
);
1523 /* On i386, reversed forms of subM3 and divM3 exist for
1524 MODE_FLOAT, so the same code that works for addM3 and mulM3
1528 /* These insns can accept the top of stack as a destination
1529 from a stack reg or mem, or can use the top of stack as a
1530 source and some other stack register (possibly top of stack)
1531 as a destination. */
1533 src1
= get_true_reg (&XEXP (pat_src
, 0));
1534 src2
= get_true_reg (&XEXP (pat_src
, 1));
1536 /* We will fix any death note later. */
1538 if (STACK_REG_P (*src1
))
1539 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1541 src1_note
= NULL_RTX
;
1542 if (STACK_REG_P (*src2
))
1543 src2_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src2
));
1545 src2_note
= NULL_RTX
;
1547 /* If either operand is not a stack register, then the dest
1548 must be top of stack. */
1550 if (! STACK_REG_P (*src1
) || ! STACK_REG_P (*src2
))
1551 emit_swap_insn (insn
, regstack
, *dest
);
1554 /* Both operands are REG. If neither operand is already
1555 at the top of stack, choose to make the one that is the dest
1556 the new top of stack. */
1558 int src1_hard_regnum
, src2_hard_regnum
;
1560 src1_hard_regnum
= get_hard_regnum (regstack
, *src1
);
1561 src2_hard_regnum
= get_hard_regnum (regstack
, *src2
);
1562 if (src1_hard_regnum
== -1 || src2_hard_regnum
== -1)
1565 if (src1_hard_regnum
!= FIRST_STACK_REG
1566 && src2_hard_regnum
!= FIRST_STACK_REG
)
1567 emit_swap_insn (insn
, regstack
, *dest
);
1570 if (STACK_REG_P (*src1
))
1571 replace_reg (src1
, get_hard_regnum (regstack
, *src1
));
1572 if (STACK_REG_P (*src2
))
1573 replace_reg (src2
, get_hard_regnum (regstack
, *src2
));
1577 rtx src1_reg
= XEXP (src1_note
, 0);
1579 /* If the register that dies is at the top of stack, then
1580 the destination is somewhere else - merely substitute it.
1581 But if the reg that dies is not at top of stack, then
1582 move the top of stack to the dead reg, as though we had
1583 done the insn and then a store-with-pop. */
1585 if (REGNO (src1_reg
) == regstack
->reg
[regstack
->top
])
1587 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1588 replace_reg (dest
, get_hard_regnum (regstack
, *dest
));
1592 int regno
= get_hard_regnum (regstack
, src1_reg
);
1594 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1595 replace_reg (dest
, regno
);
1597 regstack
->reg
[regstack
->top
- (regno
- FIRST_STACK_REG
)]
1598 = regstack
->reg
[regstack
->top
];
1601 CLEAR_HARD_REG_BIT (regstack
->reg_set
,
1602 REGNO (XEXP (src1_note
, 0)));
1603 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1608 rtx src2_reg
= XEXP (src2_note
, 0);
1609 if (REGNO (src2_reg
) == regstack
->reg
[regstack
->top
])
1611 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1612 replace_reg (dest
, get_hard_regnum (regstack
, *dest
));
1616 int regno
= get_hard_regnum (regstack
, src2_reg
);
1618 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1619 replace_reg (dest
, regno
);
1621 regstack
->reg
[regstack
->top
- (regno
- FIRST_STACK_REG
)]
1622 = regstack
->reg
[regstack
->top
];
1625 CLEAR_HARD_REG_BIT (regstack
->reg_set
,
1626 REGNO (XEXP (src2_note
, 0)));
1627 replace_reg (&XEXP (src2_note
, 0), FIRST_STACK_REG
);
1632 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1633 replace_reg (dest
, get_hard_regnum (regstack
, *dest
));
1636 /* Keep operand 1 maching with destination. */
1637 if (GET_RTX_CLASS (GET_CODE (pat_src
)) == 'c'
1638 && REG_P (*src1
) && REG_P (*src2
)
1639 && REGNO (*src1
) != REGNO (*dest
))
1648 switch (XINT (pat_src
, 1))
1652 /* These insns only operate on the top of the stack. */
1654 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1656 emit_swap_insn (insn
, regstack
, *src1
);
1658 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1660 if (STACK_REG_P (*dest
))
1661 replace_reg (dest
, FIRST_STACK_REG
);
1665 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1667 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (*src1
));
1670 replace_reg (src1
, FIRST_STACK_REG
);
1674 /* (unspec [(unspec [(compare ..)] 9)] 10)
1675 Unspec 9 is fnstsw; unspec 10 is sahf. The combination
1676 matches the PPRO fcomi instruction. */
1678 pat_src
= XVECEXP (pat_src
, 0, 0);
1679 if (GET_CODE (pat_src
) != UNSPEC
1680 || XINT (pat_src
, 1) != 9)
1685 /* (unspec [(compare ..)] 9) */
1686 /* Combined fcomp+fnstsw generated for doing well with
1687 CSE. When optimizing this would have been broken
1690 pat_src
= XVECEXP (pat_src
, 0, 0);
1691 if (GET_CODE (pat_src
) != COMPARE
)
1694 compare_for_stack_reg (insn
, regstack
, pat_src
);
1703 /* This insn requires the top of stack to be the destination. */
1705 /* If the comparison operator is an FP comparison operator,
1706 it is handled correctly by compare_for_stack_reg () who
1707 will move the destination to the top of stack. But if the
1708 comparison operator is not an FP comparison operator, we
1709 have to handle it here. */
1710 if (get_hard_regnum (regstack
, *dest
) >= FIRST_STACK_REG
1711 && REGNO (*dest
) != regstack
->reg
[regstack
->top
])
1712 emit_swap_insn (insn
, regstack
, *dest
);
1714 src1
= get_true_reg (&XEXP (pat_src
, 1));
1715 src2
= get_true_reg (&XEXP (pat_src
, 2));
1717 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1718 src2_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src2
));
1725 src_note
[1] = src1_note
;
1726 src_note
[2] = src2_note
;
1728 if (STACK_REG_P (*src1
))
1729 replace_reg (src1
, get_hard_regnum (regstack
, *src1
));
1730 if (STACK_REG_P (*src2
))
1731 replace_reg (src2
, get_hard_regnum (regstack
, *src2
));
1733 for (i
= 1; i
<= 2; i
++)
1736 int regno
= REGNO (XEXP (src_note
[i
], 0));
1738 /* If the register that dies is not at the top of
1739 stack, then move the top of stack to the dead reg */
1740 if (regno
!= regstack
->reg
[regstack
->top
])
1742 remove_regno_note (insn
, REG_DEAD
, regno
);
1743 emit_pop_insn (insn
, regstack
, XEXP (src_note
[i
], 0),
1748 CLEAR_HARD_REG_BIT (regstack
->reg_set
, regno
);
1749 replace_reg (&XEXP (src_note
[i
], 0), FIRST_STACK_REG
);
1755 /* Make dest the top of stack. Add dest to regstack if
1757 if (get_hard_regnum (regstack
, *dest
) < FIRST_STACK_REG
)
1758 regstack
->reg
[++regstack
->top
] = REGNO (*dest
);
1759 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1760 replace_reg (dest
, FIRST_STACK_REG
);
1774 /* Substitute hard regnums for any stack regs in INSN, which has
1775 N_INPUTS inputs and N_OUTPUTS outputs. REGSTACK is the stack info
1776 before the insn, and is updated with changes made here.
1778 There are several requirements and assumptions about the use of
1779 stack-like regs in asm statements. These rules are enforced by
1780 record_asm_stack_regs; see comments there for details. Any
1781 asm_operands left in the RTL at this point may be assume to meet the
1782 requirements, since record_asm_stack_regs removes any problem asm. */
1785 subst_asm_stack_regs (insn
, regstack
)
1789 rtx body
= PATTERN (insn
);
1792 rtx
*note_reg
; /* Array of note contents */
1793 rtx
**note_loc
; /* Address of REG field of each note */
1794 enum reg_note
*note_kind
; /* The type of each note */
1796 rtx
*clobber_reg
= 0;
1797 rtx
**clobber_loc
= 0;
1799 struct stack_def temp_stack
;
1804 int n_inputs
, n_outputs
;
1806 if (! check_asm_stack_operands (insn
))
1809 /* Find out what the constraints required. If no constraint
1810 alternative matches, that is a compiler bug: we should have caught
1811 such an insn in check_asm_stack_operands. */
1812 extract_insn (insn
);
1813 constrain_operands (1);
1814 alt
= which_alternative
;
1816 preprocess_constraints ();
1818 n_inputs
= get_asm_operand_n_inputs (body
);
1819 n_outputs
= recog_data
.n_operands
- n_inputs
;
1824 /* Strip SUBREGs here to make the following code simpler. */
1825 for (i
= 0; i
< recog_data
.n_operands
; i
++)
1826 if (GET_CODE (recog_data
.operand
[i
]) == SUBREG
1827 && GET_CODE (SUBREG_REG (recog_data
.operand
[i
])) == REG
)
1829 recog_data
.operand_loc
[i
] = & SUBREG_REG (recog_data
.operand
[i
]);
1830 recog_data
.operand
[i
] = SUBREG_REG (recog_data
.operand
[i
]);
1833 /* Set up NOTE_REG, NOTE_LOC and NOTE_KIND. */
1835 for (i
= 0, note
= REG_NOTES (insn
); note
; note
= XEXP (note
, 1))
1838 note_reg
= (rtx
*) alloca (i
* sizeof (rtx
));
1839 note_loc
= (rtx
**) alloca (i
* sizeof (rtx
*));
1840 note_kind
= (enum reg_note
*) alloca (i
* sizeof (enum reg_note
));
1843 for (note
= REG_NOTES (insn
); note
; note
= XEXP (note
, 1))
1845 rtx reg
= XEXP (note
, 0);
1846 rtx
*loc
= & XEXP (note
, 0);
1848 if (GET_CODE (reg
) == SUBREG
&& GET_CODE (SUBREG_REG (reg
)) == REG
)
1850 loc
= & SUBREG_REG (reg
);
1851 reg
= SUBREG_REG (reg
);
1854 if (STACK_REG_P (reg
)
1855 && (REG_NOTE_KIND (note
) == REG_DEAD
1856 || REG_NOTE_KIND (note
) == REG_UNUSED
))
1858 note_reg
[n_notes
] = reg
;
1859 note_loc
[n_notes
] = loc
;
1860 note_kind
[n_notes
] = REG_NOTE_KIND (note
);
1865 /* Set up CLOBBER_REG and CLOBBER_LOC. */
1869 if (GET_CODE (body
) == PARALLEL
)
1871 clobber_reg
= (rtx
*) alloca (XVECLEN (body
, 0) * sizeof (rtx
));
1872 clobber_loc
= (rtx
**) alloca (XVECLEN (body
, 0) * sizeof (rtx
*));
1874 for (i
= 0; i
< XVECLEN (body
, 0); i
++)
1875 if (GET_CODE (XVECEXP (body
, 0, i
)) == CLOBBER
)
1877 rtx clobber
= XVECEXP (body
, 0, i
);
1878 rtx reg
= XEXP (clobber
, 0);
1879 rtx
*loc
= & XEXP (clobber
, 0);
1881 if (GET_CODE (reg
) == SUBREG
&& GET_CODE (SUBREG_REG (reg
)) == REG
)
1883 loc
= & SUBREG_REG (reg
);
1884 reg
= SUBREG_REG (reg
);
1887 if (STACK_REG_P (reg
))
1889 clobber_reg
[n_clobbers
] = reg
;
1890 clobber_loc
[n_clobbers
] = loc
;
1896 temp_stack
= *regstack
;
1898 /* Put the input regs into the desired place in TEMP_STACK. */
1900 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
1901 if (STACK_REG_P (recog_data
.operand
[i
])
1902 && reg_class_subset_p (recog_op_alt
[i
][alt
].class,
1904 && recog_op_alt
[i
][alt
].class != FLOAT_REGS
)
1906 /* If an operand needs to be in a particular reg in
1907 FLOAT_REGS, the constraint was either 't' or 'u'. Since
1908 these constraints are for single register classes, and
1909 reload guaranteed that operand[i] is already in that class,
1910 we can just use REGNO (recog_data.operand[i]) to know which
1911 actual reg this operand needs to be in. */
1913 int regno
= get_hard_regnum (&temp_stack
, recog_data
.operand
[i
]);
1918 if (regno
!= REGNO (recog_data
.operand
[i
]))
1920 /* recog_data.operand[i] is not in the right place. Find
1921 it and swap it with whatever is already in I's place.
1922 K is where recog_data.operand[i] is now. J is where it
1926 k
= temp_stack
.top
- (regno
- FIRST_STACK_REG
);
1928 - (REGNO (recog_data
.operand
[i
]) - FIRST_STACK_REG
));
1930 temp
= temp_stack
.reg
[k
];
1931 temp_stack
.reg
[k
] = temp_stack
.reg
[j
];
1932 temp_stack
.reg
[j
] = temp
;
1936 /* Emit insns before INSN to make sure the reg-stack is in the right
1939 change_stack (insn
, regstack
, &temp_stack
, EMIT_BEFORE
);
1941 /* Make the needed input register substitutions. Do death notes and
1942 clobbers too, because these are for inputs, not outputs. */
1944 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
1945 if (STACK_REG_P (recog_data
.operand
[i
]))
1947 int regnum
= get_hard_regnum (regstack
, recog_data
.operand
[i
]);
1952 replace_reg (recog_data
.operand_loc
[i
], regnum
);
1955 for (i
= 0; i
< n_notes
; i
++)
1956 if (note_kind
[i
] == REG_DEAD
)
1958 int regnum
= get_hard_regnum (regstack
, note_reg
[i
]);
1963 replace_reg (note_loc
[i
], regnum
);
1966 for (i
= 0; i
< n_clobbers
; i
++)
1968 /* It's OK for a CLOBBER to reference a reg that is not live.
1969 Don't try to replace it in that case. */
1970 int regnum
= get_hard_regnum (regstack
, clobber_reg
[i
]);
1974 /* Sigh - clobbers always have QImode. But replace_reg knows
1975 that these regs can't be MODE_INT and will abort. Just put
1976 the right reg there without calling replace_reg. */
1978 *clobber_loc
[i
] = FP_MODE_REG (regnum
, DFmode
);
1982 /* Now remove from REGSTACK any inputs that the asm implicitly popped. */
1984 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
1985 if (STACK_REG_P (recog_data
.operand
[i
]))
1987 /* An input reg is implicitly popped if it is tied to an
1988 output, or if there is a CLOBBER for it. */
1991 for (j
= 0; j
< n_clobbers
; j
++)
1992 if (operands_match_p (clobber_reg
[j
], recog_data
.operand
[i
]))
1995 if (j
< n_clobbers
|| recog_op_alt
[i
][alt
].matches
>= 0)
1997 /* recog_data.operand[i] might not be at the top of stack.
1998 But that's OK, because all we need to do is pop the
1999 right number of regs off of the top of the reg-stack.
2000 record_asm_stack_regs guaranteed that all implicitly
2001 popped regs were grouped at the top of the reg-stack. */
2003 CLEAR_HARD_REG_BIT (regstack
->reg_set
,
2004 regstack
->reg
[regstack
->top
]);
2009 /* Now add to REGSTACK any outputs that the asm implicitly pushed.
2010 Note that there isn't any need to substitute register numbers.
2011 ??? Explain why this is true. */
2013 for (i
= LAST_STACK_REG
; i
>= FIRST_STACK_REG
; i
--)
2015 /* See if there is an output for this hard reg. */
2018 for (j
= 0; j
< n_outputs
; j
++)
2019 if (STACK_REG_P (recog_data
.operand
[j
])
2020 && REGNO (recog_data
.operand
[j
]) == i
)
2022 regstack
->reg
[++regstack
->top
] = i
;
2023 SET_HARD_REG_BIT (regstack
->reg_set
, i
);
2028 /* Now emit a pop insn for any REG_UNUSED output, or any REG_DEAD
2029 input that the asm didn't implicitly pop. If the asm didn't
2030 implicitly pop an input reg, that reg will still be live.
2032 Note that we can't use find_regno_note here: the register numbers
2033 in the death notes have already been substituted. */
2035 for (i
= 0; i
< n_outputs
; i
++)
2036 if (STACK_REG_P (recog_data
.operand
[i
]))
2040 for (j
= 0; j
< n_notes
; j
++)
2041 if (REGNO (recog_data
.operand
[i
]) == REGNO (note_reg
[j
])
2042 && note_kind
[j
] == REG_UNUSED
)
2044 insn
= emit_pop_insn (insn
, regstack
, recog_data
.operand
[i
],
2050 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
2051 if (STACK_REG_P (recog_data
.operand
[i
]))
2055 for (j
= 0; j
< n_notes
; j
++)
2056 if (REGNO (recog_data
.operand
[i
]) == REGNO (note_reg
[j
])
2057 && note_kind
[j
] == REG_DEAD
2058 && TEST_HARD_REG_BIT (regstack
->reg_set
,
2059 REGNO (recog_data
.operand
[i
])))
2061 insn
= emit_pop_insn (insn
, regstack
, recog_data
.operand
[i
],
2068 /* Substitute stack hard reg numbers for stack virtual registers in
2069 INSN. Non-stack register numbers are not changed. REGSTACK is the
2070 current stack content. Insns may be emitted as needed to arrange the
2071 stack for the 387 based on the contents of the insn. */
2074 subst_stack_regs (insn
, regstack
)
2078 register rtx
*note_link
, note
;
2081 if (GET_CODE (insn
) == CALL_INSN
)
2083 int top
= regstack
->top
;
2085 /* If there are any floating point parameters to be passed in
2086 registers for this call, make sure they are in the right
2091 straighten_stack (PREV_INSN (insn
), regstack
);
2093 /* Now mark the arguments as dead after the call. */
2095 while (regstack
->top
>= 0)
2097 CLEAR_HARD_REG_BIT (regstack
->reg_set
, FIRST_STACK_REG
+ regstack
->top
);
2103 /* Do the actual substitution if any stack regs are mentioned.
2104 Since we only record whether entire insn mentions stack regs, and
2105 subst_stack_regs_pat only works for patterns that contain stack regs,
2106 we must check each pattern in a parallel here. A call_value_pop could
2109 if (stack_regs_mentioned (insn
))
2111 int n_operands
= asm_noperands (PATTERN (insn
));
2112 if (n_operands
>= 0)
2114 /* This insn is an `asm' with operands. Decode the operands,
2115 decide how many are inputs, and do register substitution.
2116 Any REG_UNUSED notes will be handled by subst_asm_stack_regs. */
2118 subst_asm_stack_regs (insn
, regstack
);
2122 if (GET_CODE (PATTERN (insn
)) == PARALLEL
)
2123 for (i
= 0; i
< XVECLEN (PATTERN (insn
), 0); i
++)
2125 if (stack_regs_mentioned_p (XVECEXP (PATTERN (insn
), 0, i
)))
2126 subst_stack_regs_pat (insn
, regstack
,
2127 XVECEXP (PATTERN (insn
), 0, i
));
2130 subst_stack_regs_pat (insn
, regstack
, PATTERN (insn
));
2133 /* subst_stack_regs_pat may have deleted a no-op insn. If so, any
2134 REG_UNUSED will already have been dealt with, so just return. */
2136 if (GET_CODE (insn
) == NOTE
)
2139 /* If there is a REG_UNUSED note on a stack register on this insn,
2140 the indicated reg must be popped. The REG_UNUSED note is removed,
2141 since the form of the newly emitted pop insn references the reg,
2142 making it no longer `unset'. */
2144 note_link
= ®_NOTES(insn
);
2145 for (note
= *note_link
; note
; note
= XEXP (note
, 1))
2146 if (REG_NOTE_KIND (note
) == REG_UNUSED
&& STACK_REG_P (XEXP (note
, 0)))
2148 *note_link
= XEXP (note
, 1);
2149 insn
= emit_pop_insn (insn
, regstack
, XEXP (note
, 0), EMIT_AFTER
);
2152 note_link
= &XEXP (note
, 1);
2155 /* Change the organization of the stack so that it fits a new basic
2156 block. Some registers might have to be popped, but there can never be
2157 a register live in the new block that is not now live.
2159 Insert any needed insns before or after INSN, as indicated by
2160 WHERE. OLD is the original stack layout, and NEW is the desired
2161 form. OLD is updated to reflect the code emitted, ie, it will be
2162 the same as NEW upon return.
2164 This function will not preserve block_end[]. But that information
2165 is no longer needed once this has executed. */
2168 change_stack (insn
, old
, new, where
)
2172 enum emit_where where
;
2177 /* We will be inserting new insns "backwards". If we are to insert
2178 after INSN, find the next insn, and insert before it. */
2180 if (where
== EMIT_AFTER
)
2182 if (current_block
&& current_block
->end
== insn
)
2184 insn
= NEXT_INSN (insn
);
2187 /* Pop any registers that are not needed in the new block. */
2189 for (reg
= old
->top
; reg
>= 0; reg
--)
2190 if (! TEST_HARD_REG_BIT (new->reg_set
, old
->reg
[reg
]))
2191 emit_pop_insn (insn
, old
, FP_MODE_REG (old
->reg
[reg
], DFmode
),
2196 /* If the new block has never been processed, then it can inherit
2197 the old stack order. */
2199 new->top
= old
->top
;
2200 memcpy (new->reg
, old
->reg
, sizeof (new->reg
));
2204 /* This block has been entered before, and we must match the
2205 previously selected stack order. */
2207 /* By now, the only difference should be the order of the stack,
2208 not their depth or liveliness. */
2210 GO_IF_HARD_REG_EQUAL (old
->reg_set
, new->reg_set
, win
);
2213 if (old
->top
!= new->top
)
2216 /* If the stack is not empty (new->top != -1), loop here emitting
2217 swaps until the stack is correct.
2219 The worst case number of swaps emitted is N + 2, where N is the
2220 depth of the stack. In some cases, the reg at the top of
2221 stack may be correct, but swapped anyway in order to fix
2222 other regs. But since we never swap any other reg away from
2223 its correct slot, this algorithm will converge. */
2228 /* Swap the reg at top of stack into the position it is
2229 supposed to be in, until the correct top of stack appears. */
2231 while (old
->reg
[old
->top
] != new->reg
[new->top
])
2233 for (reg
= new->top
; reg
>= 0; reg
--)
2234 if (new->reg
[reg
] == old
->reg
[old
->top
])
2240 emit_swap_insn (insn
, old
,
2241 FP_MODE_REG (old
->reg
[reg
], DFmode
));
2244 /* See if any regs remain incorrect. If so, bring an
2245 incorrect reg to the top of stack, and let the while loop
2248 for (reg
= new->top
; reg
>= 0; reg
--)
2249 if (new->reg
[reg
] != old
->reg
[reg
])
2251 emit_swap_insn (insn
, old
,
2252 FP_MODE_REG (old
->reg
[reg
], DFmode
));
2257 /* At this point there must be no differences. */
2259 for (reg
= old
->top
; reg
>= 0; reg
--)
2260 if (old
->reg
[reg
] != new->reg
[reg
])
2265 current_block
->end
= PREV_INSN (insn
);
2268 /* Print stack configuration. */
2271 print_stack (file
, s
)
2279 fprintf (file
, "uninitialized\n");
2280 else if (s
->top
== -1)
2281 fprintf (file
, "empty\n");
2286 for (i
= 0; i
<= s
->top
; ++i
)
2287 fprintf (file
, "%d ", s
->reg
[i
]);
2288 fputs ("]\n", file
);
2292 /* This function was doing life analysis. We now let the regular live
2293 code do it's job, so we only need to check some extra invariants
2294 that reg-stack expects. Primary among these being that all registers
2295 are initialized before use.
2297 The function returns true when code was emitted to CFG edges and
2298 commit_edge_insertions needs to be called. */
2301 convert_regs_entry ()
2303 int inserted
= 0, i
;
2306 for (i
= n_basic_blocks
- 1; i
>= 0; --i
)
2308 basic_block block
= BASIC_BLOCK (i
);
2309 block_info bi
= BLOCK_INFO (block
);
2312 /* Set current register status at last instruction `uninitialized'. */
2313 bi
->stack_in
.top
= -2;
2315 /* Copy live_at_end and live_at_start into temporaries. */
2316 for (reg
= FIRST_STACK_REG
; reg
<= LAST_STACK_REG
; reg
++)
2318 if (REGNO_REG_SET_P (block
->global_live_at_end
, reg
))
2319 SET_HARD_REG_BIT (bi
->out_reg_set
, reg
);
2320 if (REGNO_REG_SET_P (block
->global_live_at_start
, reg
))
2321 SET_HARD_REG_BIT (bi
->stack_in
.reg_set
, reg
);
2325 /* Load something into each stack register live at function entry.
2326 Such live registers can be caused by uninitialized variables or
2327 functions not returning values on all paths. In order to keep
2328 the push/pop code happy, and to not scrog the register stack, we
2329 must put something in these registers. Use a QNaN.
2331 Note that we are insertting converted code here. This code is
2332 never seen by the convert_regs pass. */
2334 for (e
= ENTRY_BLOCK_PTR
->succ
; e
; e
= e
->succ_next
)
2336 basic_block block
= e
->dest
;
2337 block_info bi
= BLOCK_INFO (block
);
2340 for (reg
= LAST_STACK_REG
; reg
>= FIRST_STACK_REG
; --reg
)
2341 if (TEST_HARD_REG_BIT (bi
->stack_in
.reg_set
, reg
))
2345 bi
->stack_in
.reg
[++top
] = reg
;
2347 init
= gen_rtx_SET (VOIDmode
,
2348 FP_MODE_REG (FIRST_STACK_REG
, SFmode
),
2350 insert_insn_on_edge (init
, e
);
2354 bi
->stack_in
.top
= top
;
2360 /* Construct the desired stack for function exit. This will either
2361 be `empty', or the function return value at top-of-stack. */
2364 convert_regs_exit ()
2366 int value_reg_low
, value_reg_high
;
2370 retvalue
= stack_result (current_function_decl
);
2371 value_reg_low
= value_reg_high
= -1;
2374 value_reg_low
= REGNO (retvalue
);
2375 value_reg_high
= value_reg_low
2376 + HARD_REGNO_NREGS (value_reg_low
, GET_MODE (retvalue
)) - 1;
2379 output_stack
= &BLOCK_INFO (EXIT_BLOCK_PTR
)->stack_in
;
2380 if (value_reg_low
== -1)
2381 output_stack
->top
= -1;
2386 output_stack
->top
= value_reg_high
- value_reg_low
;
2387 for (reg
= value_reg_low
; reg
<= value_reg_high
; ++reg
)
2389 output_stack
->reg
[reg
- value_reg_low
] = reg
;
2390 SET_HARD_REG_BIT (output_stack
->reg_set
, reg
);
2395 /* Convert stack register references in one block. */
2398 convert_regs_1 (file
, block
)
2402 struct stack_def regstack
, tmpstack
;
2403 block_info bi
= BLOCK_INFO (block
);
2408 current_block
= block
;
2412 fprintf (file
, "\nBasic block %d\nInput stack: ", block
->index
);
2413 print_stack (file
, &bi
->stack_in
);
2416 /* Process all insns in this block. Keep track of NEXT so that we
2417 don't process insns emitted while substituting in INSN. */
2419 regstack
= bi
->stack_in
;
2423 next
= NEXT_INSN (insn
);
2425 /* Ensure we have not missed a block boundary. */
2428 if (insn
== block
->end
)
2431 /* Don't bother processing unless there is a stack reg
2432 mentioned or if it's a CALL_INSN. */
2433 if (stack_regs_mentioned (insn
)
2434 || GET_CODE (insn
) == CALL_INSN
)
2438 fprintf (file
, " insn %d input stack: ",
2440 print_stack (file
, ®stack
);
2442 subst_stack_regs (insn
, ®stack
);
2449 fprintf (file
, "Expected live registers [");
2450 for (reg
= FIRST_STACK_REG
; reg
<= LAST_STACK_REG
; ++reg
)
2451 if (TEST_HARD_REG_BIT (bi
->out_reg_set
, reg
))
2452 fprintf (file
, " %d", reg
);
2453 fprintf (file
, " ]\nOutput stack: ");
2454 print_stack (file
, ®stack
);
2458 if (GET_CODE (insn
) == JUMP_INSN
)
2459 insn
= PREV_INSN (insn
);
2461 /* If the function is declared to return a value, but it returns one
2462 in only some cases, some registers might come live here. Emit
2463 necessary moves for them. */
2465 for (reg
= FIRST_STACK_REG
; reg
<= LAST_STACK_REG
; ++reg
)
2467 if (TEST_HARD_REG_BIT (bi
->out_reg_set
, reg
)
2468 && ! TEST_HARD_REG_BIT (regstack
.reg_set
, reg
))
2474 fprintf (file
, "Emitting insn initializing reg %d\n",
2478 set
= gen_rtx_SET (VOIDmode
, FP_MODE_REG (reg
, SFmode
),
2480 insn
= emit_block_insn_after (set
, insn
, block
);
2481 subst_stack_regs (insn
, ®stack
);
2485 /* Something failed if the stack lives don't match. */
2486 GO_IF_HARD_REG_EQUAL (regstack
.reg_set
, bi
->out_reg_set
, win
);
2490 /* Adjust the stack of this block on exit to match the stack of the
2491 target block, or copy stack info into the stack of the successor
2492 of the successor hasn't been processed yet. */
2494 for (e
= block
->succ
; e
; e
= e
->succ_next
)
2496 basic_block target
= e
->dest
;
2497 stack target_stack
= &BLOCK_INFO (target
)->stack_in
;
2500 fprintf (file
, "Edge to block %d: ", target
->index
);
2502 if (target_stack
->top
== -2)
2504 /* The target block hasn't had a stack order selected.
2505 We need merely ensure that no pops are needed. */
2506 for (reg
= regstack
.top
; reg
>= 0; --reg
)
2507 if (! TEST_HARD_REG_BIT (target_stack
->reg_set
,
2514 fprintf (file
, "new block; copying stack position\n");
2516 /* change_stack kills values in regstack. */
2517 tmpstack
= regstack
;
2519 change_stack (block
->end
, &tmpstack
,
2520 target_stack
, EMIT_AFTER
);
2525 fprintf (file
, "new block; pops needed\n");
2529 if (target_stack
->top
== regstack
.top
)
2531 for (reg
= target_stack
->top
; reg
>= 0; --reg
)
2532 if (target_stack
->reg
[reg
] != regstack
.reg
[reg
])
2538 fprintf (file
, "no changes needed\n");
2545 fprintf (file
, "correcting stack to ");
2546 print_stack (file
, target_stack
);
2550 /* Care for EH edges specially. The normal return path may return
2551 a value in st(0), but the EH path will not, and there's no need
2552 to add popping code to the edge. */
2553 if (e
->flags
& (EDGE_EH
| EDGE_ABNORMAL_CALL
))
2555 /* Assert that the lifetimes are as we expect -- one value
2556 live at st(0) on the end of the source block, and no
2557 values live at the beginning of the destination block. */
2560 CLEAR_HARD_REG_SET (tmp
);
2561 GO_IF_HARD_REG_EQUAL (target_stack
->reg_set
, tmp
, eh1
);
2565 SET_HARD_REG_BIT (tmp
, FIRST_STACK_REG
);
2566 GO_IF_HARD_REG_EQUAL (regstack
.reg_set
, tmp
, eh2
);
2570 target_stack
->top
= -1;
2573 /* It is better to output directly to the end of the block
2574 instead of to the edge, because emit_swap can do minimal
2575 insn scheduling. We can do this when there is only one
2576 edge out, and it is not abnormal. */
2577 else if (block
->succ
->succ_next
== NULL
2578 && ! (e
->flags
& EDGE_ABNORMAL
))
2580 /* change_stack kills values in regstack. */
2581 tmpstack
= regstack
;
2583 change_stack (block
->end
, &tmpstack
, target_stack
,
2584 (GET_CODE (block
->end
) == JUMP_INSN
2585 ? EMIT_BEFORE
: EMIT_AFTER
));
2591 /* We don't support abnormal edges. Global takes care to
2592 avoid any live register across them, so we should never
2593 have to insert instructions on such edges. */
2594 if (e
->flags
& EDGE_ABNORMAL
)
2597 current_block
= NULL
;
2600 /* ??? change_stack needs some point to emit insns after.
2601 Also needed to keep gen_sequence from returning a
2602 pattern as opposed to a sequence, which would lose
2604 after
= emit_note (NULL
, NOTE_INSN_DELETED
);
2606 tmpstack
= regstack
;
2607 change_stack (after
, &tmpstack
, target_stack
, EMIT_BEFORE
);
2609 seq
= gen_sequence ();
2612 insert_insn_on_edge (seq
, e
);
2614 current_block
= block
;
2621 /* Convert registers in all blocks reachable from BLOCK. */
2624 convert_regs_2 (file
, block
)
2628 basic_block
*stack
, *sp
;
2631 stack
= (basic_block
*) xmalloc (sizeof (*stack
) * n_basic_blocks
);
2635 BLOCK_INFO (block
)->done
= 1;
2643 inserted
|= convert_regs_1 (file
, block
);
2645 for (e
= block
->succ
; e
; e
= e
->succ_next
)
2646 if (! BLOCK_INFO (e
->dest
)->done
)
2649 BLOCK_INFO (e
->dest
)->done
= 1;
2652 while (sp
!= stack
);
2657 /* Traverse all basic blocks in a function, converting the register
2658 references in each insn from the "flat" register file that gcc uses,
2659 to the stack-like registers the 387 uses. */
2668 /* Initialize uninitialized registers on function entry. */
2669 inserted
= convert_regs_entry ();
2671 /* Construct the desired stack for function exit. */
2672 convert_regs_exit ();
2673 BLOCK_INFO (EXIT_BLOCK_PTR
)->done
= 1;
2675 /* ??? Future: process inner loops first, and give them arbitrary
2676 initial stacks which emit_swap_insn can modify. This ought to
2677 prevent double fxch that aften appears at the head of a loop. */
2679 /* Process all blocks reachable from all entry points. */
2680 for (e
= ENTRY_BLOCK_PTR
->succ
; e
; e
= e
->succ_next
)
2681 inserted
|= convert_regs_2 (file
, e
->dest
);
2683 /* ??? Process all unreachable blocks. Though there's no excuse
2684 for keeping these even when not optimizing. */
2685 for (i
= 0; i
< n_basic_blocks
; ++i
)
2687 basic_block b
= BASIC_BLOCK (i
);
2688 block_info bi
= BLOCK_INFO (b
);
2694 /* Create an arbitrary input stack. */
2695 bi
->stack_in
.top
= -1;
2696 for (reg
= LAST_STACK_REG
; reg
>= FIRST_STACK_REG
; --reg
)
2697 if (TEST_HARD_REG_BIT (bi
->stack_in
.reg_set
, reg
))
2698 bi
->stack_in
.reg
[++bi
->stack_in
.top
] = reg
;
2700 inserted
|= convert_regs_2 (file
, b
);
2705 commit_edge_insertions ();
2712 #endif /* STACK_REGS */