1 /* Register to Stack convert for GNU compiler.
2 Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
3 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 GCC is distributed in the hope that it will be useful, but WITHOUT
13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
15 License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
22 /* This pass converts stack-like registers from the "flat register
23 file" model that gcc uses, to a stack convention that the 387 uses.
25 * The form of the input:
27 On input, the function consists of insn that have had their
28 registers fully allocated to a set of "virtual" registers. Note that
29 the word "virtual" is used differently here than elsewhere in gcc: for
30 each virtual stack reg, there is a hard reg, but the mapping between
31 them is not known until this pass is run. On output, hard register
32 numbers have been substituted, and various pop and exchange insns have
33 been emitted. The hard register numbers and the virtual register
34 numbers completely overlap - before this pass, all stack register
35 numbers are virtual, and afterward they are all hard.
37 The virtual registers can be manipulated normally by gcc, and their
38 semantics are the same as for normal registers. After the hard
39 register numbers are substituted, the semantics of an insn containing
40 stack-like regs are not the same as for an insn with normal regs: for
41 instance, it is not safe to delete an insn that appears to be a no-op
42 move. In general, no insn containing hard regs should be changed
43 after this pass is done.
45 * The form of the output:
47 After this pass, hard register numbers represent the distance from
48 the current top of stack to the desired register. A reference to
49 FIRST_STACK_REG references the top of stack, FIRST_STACK_REG + 1,
50 represents the register just below that, and so forth. Also, REG_DEAD
51 notes indicate whether or not a stack register should be popped.
53 A "swap" insn looks like a parallel of two patterns, where each
54 pattern is a SET: one sets A to B, the other B to A.
56 A "push" or "load" insn is a SET whose SET_DEST is FIRST_STACK_REG
57 and whose SET_DEST is REG or MEM. Any other SET_DEST, such as PLUS,
58 will replace the existing stack top, not push a new value.
60 A store insn is a SET whose SET_DEST is FIRST_STACK_REG, and whose
61 SET_SRC is REG or MEM.
63 The case where the SET_SRC and SET_DEST are both FIRST_STACK_REG
64 appears ambiguous. As a special case, the presence of a REG_DEAD note
65 for FIRST_STACK_REG differentiates between a load insn and a pop.
67 If a REG_DEAD is present, the insn represents a "pop" that discards
68 the top of the register stack. If there is no REG_DEAD note, then the
69 insn represents a "dup" or a push of the current top of stack onto the
74 Existing REG_DEAD and REG_UNUSED notes for stack registers are
75 deleted and recreated from scratch. REG_DEAD is never created for a
76 SET_DEST, only REG_UNUSED.
80 There are several rules on the usage of stack-like regs in
81 asm_operands insns. These rules apply only to the operands that are
84 1. Given a set of input regs that die in an asm_operands, it is
85 necessary to know which are implicitly popped by the asm, and
86 which must be explicitly popped by gcc.
88 An input reg that is implicitly popped by the asm must be
89 explicitly clobbered, unless it is constrained to match an
92 2. For any input reg that is implicitly popped by an asm, it is
93 necessary to know how to adjust the stack to compensate for the pop.
94 If any non-popped input is closer to the top of the reg-stack than
95 the implicitly popped reg, it would not be possible to know what the
96 stack looked like - it's not clear how the rest of the stack "slides
99 All implicitly popped input regs must be closer to the top of
100 the reg-stack than any input that is not implicitly popped.
102 3. It is possible that if an input dies in an insn, reload might
103 use the input reg for an output reload. Consider this example:
105 asm ("foo" : "=t" (a) : "f" (b));
107 This asm says that input B is not popped by the asm, and that
108 the asm pushes a result onto the reg-stack, i.e., the stack is one
109 deeper after the asm than it was before. But, it is possible that
110 reload will think that it can use the same reg for both the input and
111 the output, if input B dies in this insn.
113 If any input operand uses the "f" constraint, all output reg
114 constraints must use the "&" earlyclobber.
116 The asm above would be written as
118 asm ("foo" : "=&t" (a) : "f" (b));
120 4. Some operands need to be in particular places on the stack. All
121 output operands fall in this category - there is no other way to
122 know which regs the outputs appear in unless the user indicates
123 this in the constraints.
125 Output operands must specifically indicate which reg an output
126 appears in after an asm. "=f" is not allowed: the operand
127 constraints must select a class with a single reg.
129 5. Output operands may not be "inserted" between existing stack regs.
130 Since no 387 opcode uses a read/write operand, all output operands
131 are dead before the asm_operands, and are pushed by the asm_operands.
132 It makes no sense to push anywhere but the top of the reg-stack.
134 Output operands must start at the top of the reg-stack: output
135 operands may not "skip" a reg.
137 6. Some asm statements may need extra stack space for internal
138 calculations. This can be guaranteed by clobbering stack registers
139 unrelated to the inputs and outputs.
141 Here are a couple of reasonable asms to want to write. This asm
142 takes one input, which is internally popped, and produces two outputs.
144 asm ("fsincos" : "=t" (cos), "=u" (sin) : "0" (inp));
146 This asm takes two inputs, which are popped by the fyl2xp1 opcode,
147 and replaces them with one output. The user must code the "st(1)"
148 clobber for reg-stack.c to know that fyl2xp1 pops both inputs.
150 asm ("fyl2xp1" : "=t" (result) : "0" (x), "u" (y) : "st(1)");
156 #include "coretypes.h"
161 #include "function.h"
162 #include "insn-config.h"
164 #include "hard-reg-set.h"
169 #include "basic-block.h"
174 /* We use this array to cache info about insns, because otherwise we
175 spend too much time in stack_regs_mentioned_p.
177 Indexed by insn UIDs. A value of zero is uninitialized, one indicates
178 the insn uses stack registers, two indicates the insn does not use
180 static GTY(()) varray_type stack_regs_mentioned_data
;
184 #define REG_STACK_SIZE (LAST_STACK_REG - FIRST_STACK_REG + 1)
186 /* This is the basic stack record. TOP is an index into REG[] such
187 that REG[TOP] is the top of stack. If TOP is -1 the stack is empty.
189 If TOP is -2, REG[] is not yet initialized. Stack initialization
190 consists of placing each live reg in array `reg' and setting `top'
193 REG_SET indicates which registers are live. */
195 typedef struct stack_def
197 int top
; /* index to top stack element */
198 HARD_REG_SET reg_set
; /* set of live registers */
199 unsigned char reg
[REG_STACK_SIZE
];/* register - stack mapping */
202 /* This is used to carry information about basic blocks. It is
203 attached to the AUX field of the standard CFG block. */
205 typedef struct block_info_def
207 struct stack_def stack_in
; /* Input stack configuration. */
208 struct stack_def stack_out
; /* Output stack configuration. */
209 HARD_REG_SET out_reg_set
; /* Stack regs live on output. */
210 int done
; /* True if block already converted. */
211 int predecessors
; /* Number of predecessors that needs
215 #define BLOCK_INFO(B) ((block_info) (B)->aux)
217 /* Passed to change_stack to indicate where to emit insns. */
224 /* The block we're currently working on. */
225 static basic_block current_block
;
227 /* This is the register file for all register after conversion. */
229 FP_mode_reg
[LAST_STACK_REG
+1-FIRST_STACK_REG
][(int) MAX_MACHINE_MODE
];
231 #define FP_MODE_REG(regno,mode) \
232 (FP_mode_reg[(regno)-FIRST_STACK_REG][(int) (mode)])
234 /* Used to initialize uninitialized registers. */
235 static rtx not_a_num
;
237 /* Forward declarations */
239 static int stack_regs_mentioned_p (rtx pat
);
240 static void straighten_stack (rtx
, stack
);
241 static void pop_stack (stack
, int);
242 static rtx
*get_true_reg (rtx
*);
244 static int check_asm_stack_operands (rtx
);
245 static int get_asm_operand_n_inputs (rtx
);
246 static rtx
stack_result (tree
);
247 static void replace_reg (rtx
*, int);
248 static void remove_regno_note (rtx
, enum reg_note
, unsigned int);
249 static int get_hard_regnum (stack
, rtx
);
250 static rtx
emit_pop_insn (rtx
, stack
, rtx
, enum emit_where
);
251 static void emit_swap_insn (rtx
, stack
, rtx
);
252 static void swap_to_top(rtx
, stack
, rtx
, rtx
);
253 static bool move_for_stack_reg (rtx
, stack
, rtx
);
254 static bool move_nan_for_stack_reg (rtx
, stack
, rtx
);
255 static int swap_rtx_condition_1 (rtx
);
256 static int swap_rtx_condition (rtx
);
257 static void compare_for_stack_reg (rtx
, stack
, rtx
);
258 static bool subst_stack_regs_pat (rtx
, stack
, rtx
);
259 static void subst_asm_stack_regs (rtx
, stack
);
260 static bool subst_stack_regs (rtx
, stack
);
261 static void change_stack (rtx
, stack
, stack
, enum emit_where
);
262 static int convert_regs_entry (void);
263 static void convert_regs_exit (void);
264 static int convert_regs_1 (FILE *, basic_block
);
265 static int convert_regs_2 (FILE *, basic_block
);
266 static int convert_regs (FILE *);
267 static void print_stack (FILE *, stack
);
268 static rtx
next_flags_user (rtx
);
269 static bool compensate_edge (edge
, FILE *);
271 /* Return nonzero if any stack register is mentioned somewhere within PAT. */
274 stack_regs_mentioned_p (rtx pat
)
279 if (STACK_REG_P (pat
))
282 fmt
= GET_RTX_FORMAT (GET_CODE (pat
));
283 for (i
= GET_RTX_LENGTH (GET_CODE (pat
)) - 1; i
>= 0; i
--)
289 for (j
= XVECLEN (pat
, i
) - 1; j
>= 0; j
--)
290 if (stack_regs_mentioned_p (XVECEXP (pat
, i
, j
)))
293 else if (fmt
[i
] == 'e' && stack_regs_mentioned_p (XEXP (pat
, i
)))
300 /* Return nonzero if INSN mentions stacked registers, else return zero. */
303 stack_regs_mentioned (rtx insn
)
305 unsigned int uid
, max
;
308 if (! INSN_P (insn
) || !stack_regs_mentioned_data
)
311 uid
= INSN_UID (insn
);
312 max
= VARRAY_SIZE (stack_regs_mentioned_data
);
315 /* Allocate some extra size to avoid too many reallocs, but
316 do not grow too quickly. */
317 max
= uid
+ uid
/ 20;
318 VARRAY_GROW (stack_regs_mentioned_data
, max
);
321 test
= VARRAY_CHAR (stack_regs_mentioned_data
, uid
);
324 /* This insn has yet to be examined. Do so now. */
325 test
= stack_regs_mentioned_p (PATTERN (insn
)) ? 1 : 2;
326 VARRAY_CHAR (stack_regs_mentioned_data
, uid
) = test
;
332 static rtx ix86_flags_rtx
;
335 next_flags_user (rtx insn
)
337 /* Search forward looking for the first use of this value.
338 Stop at block boundaries. */
340 while (insn
!= BB_END (current_block
))
342 insn
= NEXT_INSN (insn
);
344 if (INSN_P (insn
) && reg_mentioned_p (ix86_flags_rtx
, PATTERN (insn
)))
353 /* Reorganize the stack into ascending numbers,
357 straighten_stack (rtx insn
, stack 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 (stack regstack
, int regno
)
382 int top
= regstack
->top
;
384 CLEAR_HARD_REG_BIT (regstack
->reg_set
, regno
);
386 /* If regno was not at the top of stack then adjust stack. */
387 if (regstack
->reg
[top
] != regno
)
390 for (i
= regstack
->top
; i
>= 0; i
--)
391 if (regstack
->reg
[i
] == regno
)
394 for (j
= i
; j
< top
; j
++)
395 regstack
->reg
[j
] = regstack
->reg
[j
+ 1];
401 /* Convert register usage from "flat" register file usage to a "stack
402 register file. FILE is the dump file, if used.
404 Construct a CFG and run life analysis. Then convert each insn one
405 by one. Run a last cleanup_cfg pass, if optimizing, to eliminate
406 code duplication created when the converter inserts pop insns on
410 reg_to_stack (FILE *file
)
416 /* Clean up previous run. */
417 stack_regs_mentioned_data
= 0;
419 /* See if there is something to do. Flow analysis is quite
420 expensive so we might save some compilation time. */
421 for (i
= FIRST_STACK_REG
; i
<= LAST_STACK_REG
; i
++)
422 if (regs_ever_live
[i
])
424 if (i
> LAST_STACK_REG
)
427 /* Ok, floating point instructions exist. If not optimizing,
428 build the CFG and run life analysis.
429 Also need to rebuild life when superblock scheduling is done
430 as it don't update liveness yet. */
432 || (flag_sched2_use_superblocks
433 && flag_schedule_insns_after_reload
))
435 count_or_remove_death_notes (NULL
, 1);
436 life_analysis (file
, PROP_DEATH_NOTES
);
438 mark_dfs_back_edges ();
440 /* Set up block info for each basic block. */
441 alloc_aux_for_blocks (sizeof (struct block_info_def
));
442 FOR_EACH_BB_REVERSE (bb
)
447 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
448 if (!(e
->flags
& EDGE_DFS_BACK
)
449 && e
->src
!= ENTRY_BLOCK_PTR
)
450 BLOCK_INFO (bb
)->predecessors
++;
453 /* Create the replacement registers up front. */
454 for (i
= FIRST_STACK_REG
; i
<= LAST_STACK_REG
; i
++)
456 enum machine_mode mode
;
457 for (mode
= GET_CLASS_NARROWEST_MODE (MODE_FLOAT
);
459 mode
= GET_MODE_WIDER_MODE (mode
))
460 FP_MODE_REG (i
, mode
) = gen_rtx_REG (mode
, i
);
461 for (mode
= GET_CLASS_NARROWEST_MODE (MODE_COMPLEX_FLOAT
);
463 mode
= GET_MODE_WIDER_MODE (mode
))
464 FP_MODE_REG (i
, mode
) = gen_rtx_REG (mode
, i
);
467 ix86_flags_rtx
= gen_rtx_REG (CCmode
, FLAGS_REG
);
469 /* A QNaN for initializing uninitialized variables.
471 ??? We can't load from constant memory in PIC mode, because
472 we're inserting these instructions before the prologue and
473 the PIC register hasn't been set up. In that case, fall back
474 on zero, which we can get from `ldz'. */
477 not_a_num
= CONST0_RTX (SFmode
);
480 not_a_num
= gen_lowpart (SFmode
, GEN_INT (0x7fc00000));
481 not_a_num
= force_const_mem (SFmode
, not_a_num
);
484 /* Allocate a cache for stack_regs_mentioned. */
485 max_uid
= get_max_uid ();
486 VARRAY_CHAR_INIT (stack_regs_mentioned_data
, max_uid
+ 1,
487 "stack_regs_mentioned cache");
491 free_aux_for_blocks ();
496 /* Return a pointer to the REG expression within PAT. If PAT is not a
497 REG, possible enclosed by a conversion rtx, return the inner part of
498 PAT that stopped the search. */
501 get_true_reg (rtx
*pat
)
504 switch (GET_CODE (*pat
))
507 /* Eliminate FP subregister accesses in favor of the
508 actual FP register in use. */
511 if (FP_REG_P (subreg
= SUBREG_REG (*pat
)))
513 int regno_off
= subreg_regno_offset (REGNO (subreg
),
517 *pat
= FP_MODE_REG (REGNO (subreg
) + regno_off
,
526 pat
= & XEXP (*pat
, 0);
530 if (!flag_unsafe_math_optimizations
)
532 pat
= & XEXP (*pat
, 0);
537 /* Set if we find any malformed asms in a block. */
538 static bool any_malformed_asm
;
540 /* There are many rules that an asm statement for stack-like regs must
541 follow. Those rules are explained at the top of this file: the rule
542 numbers below refer to that explanation. */
545 check_asm_stack_operands (rtx insn
)
549 int malformed_asm
= 0;
550 rtx body
= PATTERN (insn
);
552 char reg_used_as_output
[FIRST_PSEUDO_REGISTER
];
553 char implicitly_dies
[FIRST_PSEUDO_REGISTER
];
556 rtx
*clobber_reg
= 0;
557 int n_inputs
, n_outputs
;
559 /* Find out what the constraints require. If no constraint
560 alternative matches, this asm is malformed. */
562 constrain_operands (1);
563 alt
= which_alternative
;
565 preprocess_constraints ();
567 n_inputs
= get_asm_operand_n_inputs (body
);
568 n_outputs
= recog_data
.n_operands
- n_inputs
;
573 /* Avoid further trouble with this insn. */
574 PATTERN (insn
) = gen_rtx_USE (VOIDmode
, const0_rtx
);
578 /* Strip SUBREGs here to make the following code simpler. */
579 for (i
= 0; i
< recog_data
.n_operands
; i
++)
580 if (GET_CODE (recog_data
.operand
[i
]) == SUBREG
581 && REG_P (SUBREG_REG (recog_data
.operand
[i
])))
582 recog_data
.operand
[i
] = SUBREG_REG (recog_data
.operand
[i
]);
584 /* Set up CLOBBER_REG. */
588 if (GET_CODE (body
) == PARALLEL
)
590 clobber_reg
= alloca (XVECLEN (body
, 0) * sizeof (rtx
));
592 for (i
= 0; i
< XVECLEN (body
, 0); i
++)
593 if (GET_CODE (XVECEXP (body
, 0, i
)) == CLOBBER
)
595 rtx clobber
= XVECEXP (body
, 0, i
);
596 rtx reg
= XEXP (clobber
, 0);
598 if (GET_CODE (reg
) == SUBREG
&& REG_P (SUBREG_REG (reg
)))
599 reg
= SUBREG_REG (reg
);
601 if (STACK_REG_P (reg
))
603 clobber_reg
[n_clobbers
] = reg
;
609 /* Enforce rule #4: Output operands must specifically indicate which
610 reg an output appears in after an asm. "=f" is not allowed: the
611 operand constraints must select a class with a single reg.
613 Also enforce rule #5: Output operands must start at the top of
614 the reg-stack: output operands may not "skip" a reg. */
616 memset (reg_used_as_output
, 0, sizeof (reg_used_as_output
));
617 for (i
= 0; i
< n_outputs
; i
++)
618 if (STACK_REG_P (recog_data
.operand
[i
]))
620 if (reg_class_size
[(int) recog_op_alt
[i
][alt
].cl
] != 1)
622 error_for_asm (insn
, "output constraint %d must specify a single register", i
);
629 for (j
= 0; j
< n_clobbers
; j
++)
630 if (REGNO (recog_data
.operand
[i
]) == REGNO (clobber_reg
[j
]))
632 error_for_asm (insn
, "output constraint %d cannot be specified together with \"%s\" clobber",
633 i
, reg_names
[REGNO (clobber_reg
[j
])]);
638 reg_used_as_output
[REGNO (recog_data
.operand
[i
])] = 1;
643 /* Search for first non-popped reg. */
644 for (i
= FIRST_STACK_REG
; i
< LAST_STACK_REG
+ 1; i
++)
645 if (! reg_used_as_output
[i
])
648 /* If there are any other popped regs, that's an error. */
649 for (; i
< LAST_STACK_REG
+ 1; i
++)
650 if (reg_used_as_output
[i
])
653 if (i
!= LAST_STACK_REG
+ 1)
655 error_for_asm (insn
, "output regs must be grouped at top of stack");
659 /* Enforce rule #2: All implicitly popped input regs must be closer
660 to the top of the reg-stack than any input that is not implicitly
663 memset (implicitly_dies
, 0, sizeof (implicitly_dies
));
664 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
665 if (STACK_REG_P (recog_data
.operand
[i
]))
667 /* An input reg is implicitly popped if it is tied to an
668 output, or if there is a CLOBBER for it. */
671 for (j
= 0; j
< n_clobbers
; j
++)
672 if (operands_match_p (clobber_reg
[j
], recog_data
.operand
[i
]))
675 if (j
< n_clobbers
|| recog_op_alt
[i
][alt
].matches
>= 0)
676 implicitly_dies
[REGNO (recog_data
.operand
[i
])] = 1;
679 /* Search for first non-popped reg. */
680 for (i
= FIRST_STACK_REG
; i
< LAST_STACK_REG
+ 1; i
++)
681 if (! implicitly_dies
[i
])
684 /* If there are any other popped regs, that's an error. */
685 for (; i
< LAST_STACK_REG
+ 1; i
++)
686 if (implicitly_dies
[i
])
689 if (i
!= LAST_STACK_REG
+ 1)
692 "implicitly popped regs must be grouped at top of stack");
696 /* Enforce rule #3: If any input operand uses the "f" constraint, all
697 output constraints must use the "&" earlyclobber.
699 ??? Detect this more deterministically by having constrain_asm_operands
700 record any earlyclobber. */
702 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
703 if (recog_op_alt
[i
][alt
].matches
== -1)
707 for (j
= 0; j
< n_outputs
; j
++)
708 if (operands_match_p (recog_data
.operand
[j
], recog_data
.operand
[i
]))
711 "output operand %d must use %<&%> constraint", j
);
718 /* Avoid further trouble with this insn. */
719 PATTERN (insn
) = gen_rtx_USE (VOIDmode
, const0_rtx
);
720 any_malformed_asm
= true;
727 /* Calculate the number of inputs and outputs in BODY, an
728 asm_operands. N_OPERANDS is the total number of operands, and
729 N_INPUTS and N_OUTPUTS are pointers to ints into which the results are
733 get_asm_operand_n_inputs (rtx body
)
735 switch (GET_CODE (body
))
738 gcc_assert (GET_CODE (SET_SRC (body
)) == ASM_OPERANDS
);
739 return ASM_OPERANDS_INPUT_LENGTH (SET_SRC (body
));
742 return ASM_OPERANDS_INPUT_LENGTH (body
);
745 return get_asm_operand_n_inputs (XVECEXP (body
, 0, 0));
752 /* If current function returns its result in an fp stack register,
753 return the REG. Otherwise, return 0. */
756 stack_result (tree decl
)
760 /* If the value is supposed to be returned in memory, then clearly
761 it is not returned in a stack register. */
762 if (aggregate_value_p (DECL_RESULT (decl
), decl
))
765 result
= DECL_RTL_IF_SET (DECL_RESULT (decl
));
768 #ifdef FUNCTION_OUTGOING_VALUE
770 = FUNCTION_OUTGOING_VALUE (TREE_TYPE (DECL_RESULT (decl
)), decl
);
772 result
= FUNCTION_VALUE (TREE_TYPE (DECL_RESULT (decl
)), decl
);
776 return result
!= 0 && STACK_REG_P (result
) ? result
: 0;
781 * This section deals with stack register substitution, and forms the second
785 /* Replace REG, which is a pointer to a stack reg RTX, with an RTX for
786 the desired hard REGNO. */
789 replace_reg (rtx
*reg
, int regno
)
791 gcc_assert (regno
>= FIRST_STACK_REG
);
792 gcc_assert (regno
<= LAST_STACK_REG
);
793 gcc_assert (STACK_REG_P (*reg
));
795 gcc_assert (GET_MODE_CLASS (GET_MODE (*reg
)) == MODE_FLOAT
796 || GET_MODE_CLASS (GET_MODE (*reg
)) == MODE_COMPLEX_FLOAT
);
798 *reg
= FP_MODE_REG (regno
, GET_MODE (*reg
));
801 /* Remove a note of type NOTE, which must be found, for register
802 number REGNO from INSN. Remove only one such note. */
805 remove_regno_note (rtx insn
, enum reg_note note
, unsigned int regno
)
807 rtx
*note_link
, this;
809 note_link
= ®_NOTES (insn
);
810 for (this = *note_link
; this; this = XEXP (this, 1))
811 if (REG_NOTE_KIND (this) == note
812 && REG_P (XEXP (this, 0)) && REGNO (XEXP (this, 0)) == regno
)
814 *note_link
= XEXP (this, 1);
818 note_link
= &XEXP (this, 1);
823 /* Find the hard register number of virtual register REG in REGSTACK.
824 The hard register number is relative to the top of the stack. -1 is
825 returned if the register is not found. */
828 get_hard_regnum (stack regstack
, rtx reg
)
832 gcc_assert (STACK_REG_P (reg
));
834 for (i
= regstack
->top
; i
>= 0; i
--)
835 if (regstack
->reg
[i
] == REGNO (reg
))
838 return i
>= 0 ? (FIRST_STACK_REG
+ regstack
->top
- i
) : -1;
841 /* Emit an insn to pop virtual register REG before or after INSN.
842 REGSTACK is the stack state after INSN and is updated to reflect this
843 pop. WHEN is either emit_insn_before or emit_insn_after. A pop insn
844 is represented as a SET whose destination is the register to be popped
845 and source is the top of stack. A death note for the top of stack
846 cases the movdf pattern to pop. */
849 emit_pop_insn (rtx insn
, stack regstack
, rtx reg
, enum emit_where where
)
851 rtx pop_insn
, pop_rtx
;
854 /* For complex types take care to pop both halves. These may survive in
855 CLOBBER and USE expressions. */
856 if (COMPLEX_MODE_P (GET_MODE (reg
)))
858 rtx reg1
= FP_MODE_REG (REGNO (reg
), DFmode
);
859 rtx reg2
= FP_MODE_REG (REGNO (reg
) + 1, DFmode
);
862 if (get_hard_regnum (regstack
, reg1
) >= 0)
863 pop_insn
= emit_pop_insn (insn
, regstack
, reg1
, where
);
864 if (get_hard_regnum (regstack
, reg2
) >= 0)
865 pop_insn
= emit_pop_insn (insn
, regstack
, reg2
, where
);
866 gcc_assert (pop_insn
);
870 hard_regno
= get_hard_regnum (regstack
, reg
);
872 gcc_assert (hard_regno
>= FIRST_STACK_REG
);
874 pop_rtx
= gen_rtx_SET (VOIDmode
, FP_MODE_REG (hard_regno
, DFmode
),
875 FP_MODE_REG (FIRST_STACK_REG
, DFmode
));
877 if (where
== EMIT_AFTER
)
878 pop_insn
= emit_insn_after (pop_rtx
, insn
);
880 pop_insn
= emit_insn_before (pop_rtx
, insn
);
883 = gen_rtx_EXPR_LIST (REG_DEAD
, FP_MODE_REG (FIRST_STACK_REG
, DFmode
),
884 REG_NOTES (pop_insn
));
886 regstack
->reg
[regstack
->top
- (hard_regno
- FIRST_STACK_REG
)]
887 = regstack
->reg
[regstack
->top
];
889 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (reg
));
894 /* Emit an insn before or after INSN to swap virtual register REG with
895 the top of stack. REGSTACK is the stack state before the swap, and
896 is updated to reflect the swap. A swap insn is represented as a
897 PARALLEL of two patterns: each pattern moves one reg to the other.
899 If REG is already at the top of the stack, no insn is emitted. */
902 emit_swap_insn (rtx insn
, stack regstack
, rtx reg
)
906 int tmp
, other_reg
; /* swap regno temps */
907 rtx i1
; /* the stack-reg insn prior to INSN */
908 rtx i1set
= NULL_RTX
; /* the SET rtx within I1 */
910 hard_regno
= get_hard_regnum (regstack
, reg
);
912 gcc_assert (hard_regno
>= FIRST_STACK_REG
);
913 if (hard_regno
== FIRST_STACK_REG
)
916 other_reg
= regstack
->top
- (hard_regno
- FIRST_STACK_REG
);
918 tmp
= regstack
->reg
[other_reg
];
919 regstack
->reg
[other_reg
] = regstack
->reg
[regstack
->top
];
920 regstack
->reg
[regstack
->top
] = tmp
;
922 /* Find the previous insn involving stack regs, but don't pass a
925 if (current_block
&& insn
!= BB_HEAD (current_block
))
927 rtx tmp
= PREV_INSN (insn
);
928 rtx limit
= PREV_INSN (BB_HEAD (current_block
));
933 || NOTE_INSN_BASIC_BLOCK_P (tmp
)
934 || (NONJUMP_INSN_P (tmp
)
935 && stack_regs_mentioned (tmp
)))
940 tmp
= PREV_INSN (tmp
);
945 && (i1set
= single_set (i1
)) != NULL_RTX
)
947 rtx i1src
= *get_true_reg (&SET_SRC (i1set
));
948 rtx i1dest
= *get_true_reg (&SET_DEST (i1set
));
950 /* If the previous register stack push was from the reg we are to
951 swap with, omit the swap. */
953 if (REG_P (i1dest
) && REGNO (i1dest
) == FIRST_STACK_REG
955 && REGNO (i1src
) == (unsigned) hard_regno
- 1
956 && find_regno_note (i1
, REG_DEAD
, FIRST_STACK_REG
) == NULL_RTX
)
959 /* If the previous insn wrote to the reg we are to swap with,
962 if (REG_P (i1dest
) && REGNO (i1dest
) == (unsigned) hard_regno
963 && REG_P (i1src
) && REGNO (i1src
) == FIRST_STACK_REG
964 && find_regno_note (i1
, REG_DEAD
, FIRST_STACK_REG
) == NULL_RTX
)
968 swap_rtx
= gen_swapxf (FP_MODE_REG (hard_regno
, XFmode
),
969 FP_MODE_REG (FIRST_STACK_REG
, XFmode
));
972 emit_insn_after (swap_rtx
, i1
);
973 else if (current_block
)
974 emit_insn_before (swap_rtx
, BB_HEAD (current_block
));
976 emit_insn_before (swap_rtx
, insn
);
979 /* Emit an insns before INSN to swap virtual register SRC1 with
980 the top of stack and virtual register SRC2 with second stack
981 slot. REGSTACK is the stack state before the swaps, and
982 is updated to reflect the swaps. A swap insn is represented as a
983 PARALLEL of two patterns: each pattern moves one reg to the other.
985 If SRC1 and/or SRC2 are already at the right place, no swap insn
989 swap_to_top (rtx insn
, stack regstack
, rtx src1
, rtx src2
)
991 struct stack_def temp_stack
;
992 int regno
, j
, k
, temp
;
994 temp_stack
= *regstack
;
996 /* Place operand 1 at the top of stack. */
997 regno
= get_hard_regnum (&temp_stack
, src1
);
998 gcc_assert (regno
>= 0);
999 if (regno
!= FIRST_STACK_REG
)
1001 k
= temp_stack
.top
- (regno
- FIRST_STACK_REG
);
1004 temp
= temp_stack
.reg
[k
];
1005 temp_stack
.reg
[k
] = temp_stack
.reg
[j
];
1006 temp_stack
.reg
[j
] = temp
;
1009 /* Place operand 2 next on the stack. */
1010 regno
= get_hard_regnum (&temp_stack
, src2
);
1011 gcc_assert (regno
>= 0);
1012 if (regno
!= FIRST_STACK_REG
+ 1)
1014 k
= temp_stack
.top
- (regno
- FIRST_STACK_REG
);
1015 j
= temp_stack
.top
- 1;
1017 temp
= temp_stack
.reg
[k
];
1018 temp_stack
.reg
[k
] = temp_stack
.reg
[j
];
1019 temp_stack
.reg
[j
] = temp
;
1022 change_stack (insn
, regstack
, &temp_stack
, EMIT_BEFORE
);
1025 /* Handle a move to or from a stack register in PAT, which is in INSN.
1026 REGSTACK is the current stack. Return whether a control flow insn
1027 was deleted in the process. */
1030 move_for_stack_reg (rtx insn
, stack regstack
, rtx pat
)
1032 rtx
*psrc
= get_true_reg (&SET_SRC (pat
));
1033 rtx
*pdest
= get_true_reg (&SET_DEST (pat
));
1036 bool control_flow_insn_deleted
= false;
1038 src
= *psrc
; dest
= *pdest
;
1040 if (STACK_REG_P (src
) && STACK_REG_P (dest
))
1042 /* Write from one stack reg to another. If SRC dies here, then
1043 just change the register mapping and delete the insn. */
1045 note
= find_regno_note (insn
, REG_DEAD
, REGNO (src
));
1050 /* If this is a no-op move, there must not be a REG_DEAD note. */
1051 gcc_assert (REGNO (src
) != REGNO (dest
));
1053 for (i
= regstack
->top
; i
>= 0; i
--)
1054 if (regstack
->reg
[i
] == REGNO (src
))
1057 /* The destination must be dead, or life analysis is borked. */
1058 gcc_assert (get_hard_regnum (regstack
, dest
) < FIRST_STACK_REG
);
1060 /* If the source is not live, this is yet another case of
1061 uninitialized variables. Load up a NaN instead. */
1063 return move_nan_for_stack_reg (insn
, regstack
, dest
);
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
)))
1069 emit_pop_insn (insn
, regstack
, src
, EMIT_AFTER
);
1072 regstack
->reg
[i
] = REGNO (dest
);
1073 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (dest
));
1074 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (src
));
1077 control_flow_insn_deleted
|= control_flow_insn_p (insn
);
1079 return control_flow_insn_deleted
;
1082 /* The source reg does not die. */
1084 /* If this appears to be a no-op move, delete it, or else it
1085 will confuse the machine description output patterns. But if
1086 it is REG_UNUSED, we must pop the reg now, as per-insn processing
1087 for REG_UNUSED will not work for deleted insns. */
1089 if (REGNO (src
) == REGNO (dest
))
1091 if (find_regno_note (insn
, REG_UNUSED
, REGNO (dest
)))
1092 emit_pop_insn (insn
, regstack
, dest
, EMIT_AFTER
);
1094 control_flow_insn_deleted
|= control_flow_insn_p (insn
);
1096 return control_flow_insn_deleted
;
1099 /* The destination ought to be dead. */
1100 gcc_assert (get_hard_regnum (regstack
, dest
) < FIRST_STACK_REG
);
1102 replace_reg (psrc
, get_hard_regnum (regstack
, src
));
1104 regstack
->reg
[++regstack
->top
] = REGNO (dest
);
1105 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (dest
));
1106 replace_reg (pdest
, FIRST_STACK_REG
);
1108 else if (STACK_REG_P (src
))
1110 /* Save from a stack reg to MEM, or possibly integer reg. Since
1111 only top of stack may be saved, emit an exchange first if
1114 emit_swap_insn (insn
, regstack
, src
);
1116 note
= find_regno_note (insn
, REG_DEAD
, REGNO (src
));
1119 replace_reg (&XEXP (note
, 0), FIRST_STACK_REG
);
1121 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (src
));
1123 else if ((GET_MODE (src
) == XFmode
)
1124 && regstack
->top
< REG_STACK_SIZE
- 1)
1126 /* A 387 cannot write an XFmode value to a MEM without
1127 clobbering the source reg. The output code can handle
1128 this by reading back the value from the MEM.
1129 But it is more efficient to use a temp register if one is
1130 available. Push the source value here if the register
1131 stack is not full, and then write the value to memory via
1134 rtx top_stack_reg
= FP_MODE_REG (FIRST_STACK_REG
, GET_MODE (src
));
1136 push_rtx
= gen_movxf (top_stack_reg
, top_stack_reg
);
1137 emit_insn_before (push_rtx
, insn
);
1138 REG_NOTES (insn
) = gen_rtx_EXPR_LIST (REG_DEAD
, top_stack_reg
,
1142 replace_reg (psrc
, FIRST_STACK_REG
);
1146 gcc_assert (STACK_REG_P (dest
));
1148 /* Load from MEM, or possibly integer REG or constant, into the
1149 stack regs. The actual target is always the top of the
1150 stack. The stack mapping is changed to reflect that DEST is
1151 now at top of stack. */
1153 /* The destination ought to be dead. */
1154 gcc_assert (get_hard_regnum (regstack
, dest
) < FIRST_STACK_REG
);
1156 gcc_assert (regstack
->top
< REG_STACK_SIZE
);
1158 regstack
->reg
[++regstack
->top
] = REGNO (dest
);
1159 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (dest
));
1160 replace_reg (pdest
, FIRST_STACK_REG
);
1163 return control_flow_insn_deleted
;
1166 /* A helper function which replaces INSN with a pattern that loads up
1167 a NaN into DEST, then invokes move_for_stack_reg. */
1170 move_nan_for_stack_reg (rtx insn
, stack regstack
, rtx dest
)
1174 dest
= FP_MODE_REG (REGNO (dest
), SFmode
);
1175 pat
= gen_rtx_SET (VOIDmode
, dest
, not_a_num
);
1176 PATTERN (insn
) = pat
;
1177 INSN_CODE (insn
) = -1;
1179 return move_for_stack_reg (insn
, regstack
, pat
);
1182 /* Swap the condition on a branch, if there is one. Return true if we
1183 found a condition to swap. False if the condition was not used as
1187 swap_rtx_condition_1 (rtx pat
)
1192 if (COMPARISON_P (pat
))
1194 PUT_CODE (pat
, swap_condition (GET_CODE (pat
)));
1199 fmt
= GET_RTX_FORMAT (GET_CODE (pat
));
1200 for (i
= GET_RTX_LENGTH (GET_CODE (pat
)) - 1; i
>= 0; i
--)
1206 for (j
= XVECLEN (pat
, i
) - 1; j
>= 0; j
--)
1207 r
|= swap_rtx_condition_1 (XVECEXP (pat
, i
, j
));
1209 else if (fmt
[i
] == 'e')
1210 r
|= swap_rtx_condition_1 (XEXP (pat
, i
));
1218 swap_rtx_condition (rtx insn
)
1220 rtx pat
= PATTERN (insn
);
1222 /* We're looking for a single set to cc0 or an HImode temporary. */
1224 if (GET_CODE (pat
) == SET
1225 && REG_P (SET_DEST (pat
))
1226 && REGNO (SET_DEST (pat
)) == FLAGS_REG
)
1228 insn
= next_flags_user (insn
);
1229 if (insn
== NULL_RTX
)
1231 pat
= PATTERN (insn
);
1234 /* See if this is, or ends in, a fnstsw, aka unspec 9. If so, we're
1235 not doing anything with the cc value right now. We may be able to
1236 search for one though. */
1238 if (GET_CODE (pat
) == SET
1239 && GET_CODE (SET_SRC (pat
)) == UNSPEC
1240 && XINT (SET_SRC (pat
), 1) == UNSPEC_FNSTSW
)
1242 rtx dest
= SET_DEST (pat
);
1244 /* Search forward looking for the first use of this value.
1245 Stop at block boundaries. */
1246 while (insn
!= BB_END (current_block
))
1248 insn
= NEXT_INSN (insn
);
1249 if (INSN_P (insn
) && reg_mentioned_p (dest
, insn
))
1255 /* So we've found the insn using this value. If it is anything
1256 other than sahf, aka unspec 10, or the value does not die
1257 (meaning we'd have to search further), then we must give up. */
1258 pat
= PATTERN (insn
);
1259 if (GET_CODE (pat
) != SET
1260 || GET_CODE (SET_SRC (pat
)) != UNSPEC
1261 || XINT (SET_SRC (pat
), 1) != UNSPEC_SAHF
1262 || ! dead_or_set_p (insn
, dest
))
1265 /* Now we are prepared to handle this as a normal cc0 setter. */
1266 insn
= next_flags_user (insn
);
1267 if (insn
== NULL_RTX
)
1269 pat
= PATTERN (insn
);
1272 if (swap_rtx_condition_1 (pat
))
1275 INSN_CODE (insn
) = -1;
1276 if (recog_memoized (insn
) == -1)
1278 /* In case the flags don't die here, recurse to try fix
1279 following user too. */
1280 else if (! dead_or_set_p (insn
, ix86_flags_rtx
))
1282 insn
= next_flags_user (insn
);
1283 if (!insn
|| !swap_rtx_condition (insn
))
1288 swap_rtx_condition_1 (pat
);
1296 /* Handle a comparison. Special care needs to be taken to avoid
1297 causing comparisons that a 387 cannot do correctly, such as EQ.
1299 Also, a pop insn may need to be emitted. The 387 does have an
1300 `fcompp' insn that can pop two regs, but it is sometimes too expensive
1301 to do this - a `fcomp' followed by a `fstpl %st(0)' may be easier to
1305 compare_for_stack_reg (rtx insn
, stack regstack
, rtx pat_src
)
1308 rtx src1_note
, src2_note
;
1310 src1
= get_true_reg (&XEXP (pat_src
, 0));
1311 src2
= get_true_reg (&XEXP (pat_src
, 1));
1313 /* ??? If fxch turns out to be cheaper than fstp, give priority to
1314 registers that die in this insn - move those to stack top first. */
1315 if ((! STACK_REG_P (*src1
)
1316 || (STACK_REG_P (*src2
)
1317 && get_hard_regnum (regstack
, *src2
) == FIRST_STACK_REG
))
1318 && swap_rtx_condition (insn
))
1321 temp
= XEXP (pat_src
, 0);
1322 XEXP (pat_src
, 0) = XEXP (pat_src
, 1);
1323 XEXP (pat_src
, 1) = temp
;
1325 src1
= get_true_reg (&XEXP (pat_src
, 0));
1326 src2
= get_true_reg (&XEXP (pat_src
, 1));
1328 INSN_CODE (insn
) = -1;
1331 /* We will fix any death note later. */
1333 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1335 if (STACK_REG_P (*src2
))
1336 src2_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src2
));
1338 src2_note
= NULL_RTX
;
1340 emit_swap_insn (insn
, regstack
, *src1
);
1342 replace_reg (src1
, FIRST_STACK_REG
);
1344 if (STACK_REG_P (*src2
))
1345 replace_reg (src2
, get_hard_regnum (regstack
, *src2
));
1349 pop_stack (regstack
, REGNO (XEXP (src1_note
, 0)));
1350 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1353 /* If the second operand dies, handle that. But if the operands are
1354 the same stack register, don't bother, because only one death is
1355 needed, and it was just handled. */
1358 && ! (STACK_REG_P (*src1
) && STACK_REG_P (*src2
)
1359 && REGNO (*src1
) == REGNO (*src2
)))
1361 /* As a special case, two regs may die in this insn if src2 is
1362 next to top of stack and the top of stack also dies. Since
1363 we have already popped src1, "next to top of stack" is really
1364 at top (FIRST_STACK_REG) now. */
1366 if (get_hard_regnum (regstack
, XEXP (src2_note
, 0)) == FIRST_STACK_REG
1369 pop_stack (regstack
, REGNO (XEXP (src2_note
, 0)));
1370 replace_reg (&XEXP (src2_note
, 0), FIRST_STACK_REG
+ 1);
1374 /* The 386 can only represent death of the first operand in
1375 the case handled above. In all other cases, emit a separate
1376 pop and remove the death note from here. */
1378 /* link_cc0_insns (insn); */
1380 remove_regno_note (insn
, REG_DEAD
, REGNO (XEXP (src2_note
, 0)));
1382 emit_pop_insn (insn
, regstack
, XEXP (src2_note
, 0),
1388 /* Substitute new registers in PAT, which is part of INSN. REGSTACK
1389 is the current register layout. Return whether a control flow insn
1390 was deleted in the process. */
1393 subst_stack_regs_pat (rtx insn
, stack regstack
, rtx pat
)
1396 bool control_flow_insn_deleted
= false;
1398 switch (GET_CODE (pat
))
1401 /* Deaths in USE insns can happen in non optimizing compilation.
1402 Handle them by popping the dying register. */
1403 src
= get_true_reg (&XEXP (pat
, 0));
1404 if (STACK_REG_P (*src
)
1405 && find_regno_note (insn
, REG_DEAD
, REGNO (*src
)))
1407 emit_pop_insn (insn
, regstack
, *src
, EMIT_AFTER
);
1408 return control_flow_insn_deleted
;
1410 /* ??? Uninitialized USE should not happen. */
1412 gcc_assert (get_hard_regnum (regstack
, *src
) != -1);
1419 dest
= get_true_reg (&XEXP (pat
, 0));
1420 if (STACK_REG_P (*dest
))
1422 note
= find_reg_note (insn
, REG_DEAD
, *dest
);
1424 if (pat
!= PATTERN (insn
))
1426 /* The fix_truncdi_1 pattern wants to be able to allocate
1427 it's own scratch register. It does this by clobbering
1428 an fp reg so that it is assured of an empty reg-stack
1429 register. If the register is live, kill it now.
1430 Remove the DEAD/UNUSED note so we don't try to kill it
1434 emit_pop_insn (insn
, regstack
, *dest
, EMIT_BEFORE
);
1437 note
= find_reg_note (insn
, REG_UNUSED
, *dest
);
1440 remove_note (insn
, note
);
1441 replace_reg (dest
, FIRST_STACK_REG
+ 1);
1445 /* A top-level clobber with no REG_DEAD, and no hard-regnum
1446 indicates an uninitialized value. Because reload removed
1447 all other clobbers, this must be due to a function
1448 returning without a value. Load up a NaN. */
1453 if (get_hard_regnum (regstack
, t
) == -1)
1454 control_flow_insn_deleted
1455 |= move_nan_for_stack_reg (insn
, regstack
, t
);
1456 if (COMPLEX_MODE_P (GET_MODE (t
)))
1458 t
= FP_MODE_REG (REGNO (t
) + 1, DFmode
);
1459 if (get_hard_regnum (regstack
, t
) == -1)
1460 control_flow_insn_deleted
1461 |= move_nan_for_stack_reg (insn
, regstack
, t
);
1471 rtx
*src1
= (rtx
*) 0, *src2
;
1472 rtx src1_note
, src2_note
;
1475 dest
= get_true_reg (&SET_DEST (pat
));
1476 src
= get_true_reg (&SET_SRC (pat
));
1477 pat_src
= SET_SRC (pat
);
1479 /* See if this is a `movM' pattern, and handle elsewhere if so. */
1480 if (STACK_REG_P (*src
)
1481 || (STACK_REG_P (*dest
)
1482 && (REG_P (*src
) || MEM_P (*src
)
1483 || GET_CODE (*src
) == CONST_DOUBLE
)))
1485 control_flow_insn_deleted
|= move_for_stack_reg (insn
, regstack
, pat
);
1489 switch (GET_CODE (pat_src
))
1492 compare_for_stack_reg (insn
, regstack
, pat_src
);
1498 for (count
= hard_regno_nregs
[REGNO (*dest
)][GET_MODE (*dest
)];
1501 regstack
->reg
[++regstack
->top
] = REGNO (*dest
) + count
;
1502 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
) + count
);
1505 replace_reg (dest
, FIRST_STACK_REG
);
1509 /* This is a `tstM2' case. */
1510 gcc_assert (*dest
== cc0_rtx
);
1515 case FLOAT_TRUNCATE
:
1519 /* These insns only operate on the top of the stack. DEST might
1520 be cc0_rtx if we're processing a tstM pattern. Also, it's
1521 possible that the tstM case results in a REG_DEAD note on the
1525 src1
= get_true_reg (&XEXP (pat_src
, 0));
1527 emit_swap_insn (insn
, regstack
, *src1
);
1529 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1531 if (STACK_REG_P (*dest
))
1532 replace_reg (dest
, FIRST_STACK_REG
);
1536 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1538 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (*src1
));
1541 replace_reg (src1
, FIRST_STACK_REG
);
1546 /* On i386, reversed forms of subM3 and divM3 exist for
1547 MODE_FLOAT, so the same code that works for addM3 and mulM3
1551 /* These insns can accept the top of stack as a destination
1552 from a stack reg or mem, or can use the top of stack as a
1553 source and some other stack register (possibly top of stack)
1554 as a destination. */
1556 src1
= get_true_reg (&XEXP (pat_src
, 0));
1557 src2
= get_true_reg (&XEXP (pat_src
, 1));
1559 /* We will fix any death note later. */
1561 if (STACK_REG_P (*src1
))
1562 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1564 src1_note
= NULL_RTX
;
1565 if (STACK_REG_P (*src2
))
1566 src2_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src2
));
1568 src2_note
= NULL_RTX
;
1570 /* If either operand is not a stack register, then the dest
1571 must be top of stack. */
1573 if (! STACK_REG_P (*src1
) || ! STACK_REG_P (*src2
))
1574 emit_swap_insn (insn
, regstack
, *dest
);
1577 /* Both operands are REG. If neither operand is already
1578 at the top of stack, choose to make the one that is the dest
1579 the new top of stack. */
1581 int src1_hard_regnum
, src2_hard_regnum
;
1583 src1_hard_regnum
= get_hard_regnum (regstack
, *src1
);
1584 src2_hard_regnum
= get_hard_regnum (regstack
, *src2
);
1585 gcc_assert (src1_hard_regnum
!= -1);
1586 gcc_assert (src2_hard_regnum
!= -1);
1588 if (src1_hard_regnum
!= FIRST_STACK_REG
1589 && src2_hard_regnum
!= FIRST_STACK_REG
)
1590 emit_swap_insn (insn
, regstack
, *dest
);
1593 if (STACK_REG_P (*src1
))
1594 replace_reg (src1
, get_hard_regnum (regstack
, *src1
));
1595 if (STACK_REG_P (*src2
))
1596 replace_reg (src2
, get_hard_regnum (regstack
, *src2
));
1600 rtx src1_reg
= XEXP (src1_note
, 0);
1602 /* If the register that dies is at the top of stack, then
1603 the destination is somewhere else - merely substitute it.
1604 But if the reg that dies is not at top of stack, then
1605 move the top of stack to the dead reg, as though we had
1606 done the insn and then a store-with-pop. */
1608 if (REGNO (src1_reg
) == regstack
->reg
[regstack
->top
])
1610 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1611 replace_reg (dest
, get_hard_regnum (regstack
, *dest
));
1615 int regno
= get_hard_regnum (regstack
, src1_reg
);
1617 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1618 replace_reg (dest
, regno
);
1620 regstack
->reg
[regstack
->top
- (regno
- FIRST_STACK_REG
)]
1621 = regstack
->reg
[regstack
->top
];
1624 CLEAR_HARD_REG_BIT (regstack
->reg_set
,
1625 REGNO (XEXP (src1_note
, 0)));
1626 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1631 rtx src2_reg
= XEXP (src2_note
, 0);
1632 if (REGNO (src2_reg
) == regstack
->reg
[regstack
->top
])
1634 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1635 replace_reg (dest
, get_hard_regnum (regstack
, *dest
));
1639 int regno
= get_hard_regnum (regstack
, src2_reg
);
1641 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1642 replace_reg (dest
, regno
);
1644 regstack
->reg
[regstack
->top
- (regno
- FIRST_STACK_REG
)]
1645 = regstack
->reg
[regstack
->top
];
1648 CLEAR_HARD_REG_BIT (regstack
->reg_set
,
1649 REGNO (XEXP (src2_note
, 0)));
1650 replace_reg (&XEXP (src2_note
, 0), FIRST_STACK_REG
);
1655 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1656 replace_reg (dest
, get_hard_regnum (regstack
, *dest
));
1659 /* Keep operand 1 matching with destination. */
1660 if (COMMUTATIVE_ARITH_P (pat_src
)
1661 && REG_P (*src1
) && REG_P (*src2
)
1662 && REGNO (*src1
) != REGNO (*dest
))
1664 int tmp
= REGNO (*src1
);
1665 replace_reg (src1
, REGNO (*src2
));
1666 replace_reg (src2
, tmp
);
1671 switch (XINT (pat_src
, 1))
1674 /* These insns only operate on the top of the stack. */
1676 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1677 emit_swap_insn (insn
, regstack
, *src1
);
1679 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1681 if (STACK_REG_P (*dest
))
1682 replace_reg (dest
, FIRST_STACK_REG
);
1686 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1688 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (*src1
));
1691 replace_reg (src1
, FIRST_STACK_REG
);
1696 case UNSPEC_FRNDINT
:
1699 case UNSPEC_FRNDINT_FLOOR
:
1700 case UNSPEC_FRNDINT_CEIL
:
1701 case UNSPEC_FRNDINT_TRUNC
:
1702 case UNSPEC_FRNDINT_MASK_PM
:
1704 /* These insns only operate on the top of the stack. */
1706 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1708 emit_swap_insn (insn
, regstack
, *src1
);
1710 /* Input should never die, it is
1711 replaced with output. */
1712 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1713 gcc_assert (!src1_note
);
1715 if (STACK_REG_P (*dest
))
1716 replace_reg (dest
, FIRST_STACK_REG
);
1718 replace_reg (src1
, FIRST_STACK_REG
);
1723 case UNSPEC_FYL2XP1
:
1724 /* These insns operate on the top two stack slots. */
1726 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1727 src2
= get_true_reg (&XVECEXP (pat_src
, 0, 1));
1729 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1730 src2_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src2
));
1732 swap_to_top (insn
, regstack
, *src1
, *src2
);
1734 replace_reg (src1
, FIRST_STACK_REG
);
1735 replace_reg (src2
, FIRST_STACK_REG
+ 1);
1738 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1740 replace_reg (&XEXP (src2_note
, 0), FIRST_STACK_REG
+ 1);
1742 /* Pop both input operands from the stack. */
1743 CLEAR_HARD_REG_BIT (regstack
->reg_set
,
1744 regstack
->reg
[regstack
->top
]);
1745 CLEAR_HARD_REG_BIT (regstack
->reg_set
,
1746 regstack
->reg
[regstack
->top
- 1]);
1749 /* Push the result back onto the stack. */
1750 regstack
->reg
[++regstack
->top
] = REGNO (*dest
);
1751 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1752 replace_reg (dest
, FIRST_STACK_REG
);
1755 case UNSPEC_FSCALE_FRACT
:
1756 case UNSPEC_FPREM_F
:
1757 case UNSPEC_FPREM1_F
:
1758 /* These insns operate on the top two stack slots.
1759 first part of double input, double output insn. */
1761 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1762 src2
= get_true_reg (&XVECEXP (pat_src
, 0, 1));
1764 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1765 src2_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src2
));
1767 /* Inputs should never die, they are
1768 replaced with outputs. */
1769 gcc_assert (!src1_note
);
1770 gcc_assert (!src2_note
);
1772 swap_to_top (insn
, regstack
, *src1
, *src2
);
1774 /* Push the result back onto stack. Empty stack slot
1775 will be filled in second part of insn. */
1776 if (STACK_REG_P (*dest
)) {
1777 regstack
->reg
[regstack
->top
] = REGNO (*dest
);
1778 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1779 replace_reg (dest
, FIRST_STACK_REG
);
1782 replace_reg (src1
, FIRST_STACK_REG
);
1783 replace_reg (src2
, FIRST_STACK_REG
+ 1);
1786 case UNSPEC_FSCALE_EXP
:
1787 case UNSPEC_FPREM_U
:
1788 case UNSPEC_FPREM1_U
:
1789 /* These insns operate on the top two stack slots./
1790 second part of double input, double output insn. */
1792 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1793 src2
= get_true_reg (&XVECEXP (pat_src
, 0, 1));
1795 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1796 src2_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src2
));
1798 /* Inputs should never die, they are
1799 replaced with outputs. */
1800 gcc_assert (!src1_note
);
1801 gcc_assert (!src2_note
);
1803 swap_to_top (insn
, regstack
, *src1
, *src2
);
1805 /* Push the result back onto stack. Fill empty slot from
1806 first part of insn and fix top of stack pointer. */
1807 if (STACK_REG_P (*dest
)) {
1808 regstack
->reg
[regstack
->top
- 1] = REGNO (*dest
);
1809 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1810 replace_reg (dest
, FIRST_STACK_REG
+ 1);
1813 replace_reg (src1
, FIRST_STACK_REG
);
1814 replace_reg (src2
, FIRST_STACK_REG
+ 1);
1817 case UNSPEC_SINCOS_COS
:
1818 case UNSPEC_TAN_ONE
:
1819 case UNSPEC_XTRACT_FRACT
:
1820 /* These insns operate on the top two stack slots,
1821 first part of one input, double output insn. */
1823 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1825 emit_swap_insn (insn
, regstack
, *src1
);
1827 /* Input should never die, it is
1828 replaced with output. */
1829 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1830 gcc_assert (!src1_note
);
1832 /* Push the result back onto stack. Empty stack slot
1833 will be filled in second part of insn. */
1834 if (STACK_REG_P (*dest
)) {
1835 regstack
->reg
[regstack
->top
+ 1] = REGNO (*dest
);
1836 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1837 replace_reg (dest
, FIRST_STACK_REG
);
1840 replace_reg (src1
, FIRST_STACK_REG
);
1843 case UNSPEC_SINCOS_SIN
:
1844 case UNSPEC_TAN_TAN
:
1845 case UNSPEC_XTRACT_EXP
:
1846 /* These insns operate on the top two stack slots,
1847 second part of one input, double output insn. */
1849 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1851 emit_swap_insn (insn
, regstack
, *src1
);
1853 /* Input should never die, it is
1854 replaced with output. */
1855 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1856 gcc_assert (!src1_note
);
1858 /* Push the result back onto stack. Fill empty slot from
1859 first part of insn and fix top of stack pointer. */
1860 if (STACK_REG_P (*dest
)) {
1861 regstack
->reg
[regstack
->top
] = REGNO (*dest
);
1862 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1863 replace_reg (dest
, FIRST_STACK_REG
+ 1);
1868 replace_reg (src1
, FIRST_STACK_REG
);
1872 /* (unspec [(unspec [(compare)] UNSPEC_FNSTSW)] UNSPEC_SAHF)
1873 The combination matches the PPRO fcomi instruction. */
1875 pat_src
= XVECEXP (pat_src
, 0, 0);
1876 gcc_assert (GET_CODE (pat_src
) == UNSPEC
);
1877 gcc_assert (XINT (pat_src
, 1) == UNSPEC_FNSTSW
);
1881 /* Combined fcomp+fnstsw generated for doing well with
1882 CSE. When optimizing this would have been broken
1885 pat_src
= XVECEXP (pat_src
, 0, 0);
1886 gcc_assert (GET_CODE (pat_src
) == COMPARE
);
1888 compare_for_stack_reg (insn
, regstack
, pat_src
);
1897 /* This insn requires the top of stack to be the destination. */
1899 src1
= get_true_reg (&XEXP (pat_src
, 1));
1900 src2
= get_true_reg (&XEXP (pat_src
, 2));
1902 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1903 src2_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src2
));
1905 /* If the comparison operator is an FP comparison operator,
1906 it is handled correctly by compare_for_stack_reg () who
1907 will move the destination to the top of stack. But if the
1908 comparison operator is not an FP comparison operator, we
1909 have to handle it here. */
1910 if (get_hard_regnum (regstack
, *dest
) >= FIRST_STACK_REG
1911 && REGNO (*dest
) != regstack
->reg
[regstack
->top
])
1913 /* In case one of operands is the top of stack and the operands
1914 dies, it is safe to make it the destination operand by
1915 reversing the direction of cmove and avoid fxch. */
1916 if ((REGNO (*src1
) == regstack
->reg
[regstack
->top
]
1918 || (REGNO (*src2
) == regstack
->reg
[regstack
->top
]
1921 int idx1
= (get_hard_regnum (regstack
, *src1
)
1923 int idx2
= (get_hard_regnum (regstack
, *src2
)
1926 /* Make reg-stack believe that the operands are already
1927 swapped on the stack */
1928 regstack
->reg
[regstack
->top
- idx1
] = REGNO (*src2
);
1929 regstack
->reg
[regstack
->top
- idx2
] = REGNO (*src1
);
1931 /* Reverse condition to compensate the operand swap.
1932 i386 do have comparison always reversible. */
1933 PUT_CODE (XEXP (pat_src
, 0),
1934 reversed_comparison_code (XEXP (pat_src
, 0), insn
));
1937 emit_swap_insn (insn
, regstack
, *dest
);
1945 src_note
[1] = src1_note
;
1946 src_note
[2] = src2_note
;
1948 if (STACK_REG_P (*src1
))
1949 replace_reg (src1
, get_hard_regnum (regstack
, *src1
));
1950 if (STACK_REG_P (*src2
))
1951 replace_reg (src2
, get_hard_regnum (regstack
, *src2
));
1953 for (i
= 1; i
<= 2; i
++)
1956 int regno
= REGNO (XEXP (src_note
[i
], 0));
1958 /* If the register that dies is not at the top of
1959 stack, then move the top of stack to the dead reg.
1960 Top of stack should never die, as it is the
1962 gcc_assert (regno
!= regstack
->reg
[regstack
->top
]);
1963 remove_regno_note (insn
, REG_DEAD
, regno
);
1964 emit_pop_insn (insn
, regstack
, XEXP (src_note
[i
], 0),
1969 /* Make dest the top of stack. Add dest to regstack if
1971 if (get_hard_regnum (regstack
, *dest
) < FIRST_STACK_REG
)
1972 regstack
->reg
[++regstack
->top
] = REGNO (*dest
);
1973 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1974 replace_reg (dest
, FIRST_STACK_REG
);
1987 return control_flow_insn_deleted
;
1990 /* Substitute hard regnums for any stack regs in INSN, which has
1991 N_INPUTS inputs and N_OUTPUTS outputs. REGSTACK is the stack info
1992 before the insn, and is updated with changes made here.
1994 There are several requirements and assumptions about the use of
1995 stack-like regs in asm statements. These rules are enforced by
1996 record_asm_stack_regs; see comments there for details. Any
1997 asm_operands left in the RTL at this point may be assume to meet the
1998 requirements, since record_asm_stack_regs removes any problem asm. */
2001 subst_asm_stack_regs (rtx insn
, stack regstack
)
2003 rtx body
= PATTERN (insn
);
2006 rtx
*note_reg
; /* Array of note contents */
2007 rtx
**note_loc
; /* Address of REG field of each note */
2008 enum reg_note
*note_kind
; /* The type of each note */
2010 rtx
*clobber_reg
= 0;
2011 rtx
**clobber_loc
= 0;
2013 struct stack_def temp_stack
;
2018 int n_inputs
, n_outputs
;
2020 if (! check_asm_stack_operands (insn
))
2023 /* Find out what the constraints required. If no constraint
2024 alternative matches, that is a compiler bug: we should have caught
2025 such an insn in check_asm_stack_operands. */
2026 extract_insn (insn
);
2027 constrain_operands (1);
2028 alt
= which_alternative
;
2030 preprocess_constraints ();
2032 n_inputs
= get_asm_operand_n_inputs (body
);
2033 n_outputs
= recog_data
.n_operands
- n_inputs
;
2035 gcc_assert (alt
>= 0);
2037 /* Strip SUBREGs here to make the following code simpler. */
2038 for (i
= 0; i
< recog_data
.n_operands
; i
++)
2039 if (GET_CODE (recog_data
.operand
[i
]) == SUBREG
2040 && REG_P (SUBREG_REG (recog_data
.operand
[i
])))
2042 recog_data
.operand_loc
[i
] = & SUBREG_REG (recog_data
.operand
[i
]);
2043 recog_data
.operand
[i
] = SUBREG_REG (recog_data
.operand
[i
]);
2046 /* Set up NOTE_REG, NOTE_LOC and NOTE_KIND. */
2048 for (i
= 0, note
= REG_NOTES (insn
); note
; note
= XEXP (note
, 1))
2051 note_reg
= alloca (i
* sizeof (rtx
));
2052 note_loc
= alloca (i
* sizeof (rtx
*));
2053 note_kind
= alloca (i
* sizeof (enum reg_note
));
2056 for (note
= REG_NOTES (insn
); note
; note
= XEXP (note
, 1))
2058 rtx reg
= XEXP (note
, 0);
2059 rtx
*loc
= & XEXP (note
, 0);
2061 if (GET_CODE (reg
) == SUBREG
&& REG_P (SUBREG_REG (reg
)))
2063 loc
= & SUBREG_REG (reg
);
2064 reg
= SUBREG_REG (reg
);
2067 if (STACK_REG_P (reg
)
2068 && (REG_NOTE_KIND (note
) == REG_DEAD
2069 || REG_NOTE_KIND (note
) == REG_UNUSED
))
2071 note_reg
[n_notes
] = reg
;
2072 note_loc
[n_notes
] = loc
;
2073 note_kind
[n_notes
] = REG_NOTE_KIND (note
);
2078 /* Set up CLOBBER_REG and CLOBBER_LOC. */
2082 if (GET_CODE (body
) == PARALLEL
)
2084 clobber_reg
= alloca (XVECLEN (body
, 0) * sizeof (rtx
));
2085 clobber_loc
= alloca (XVECLEN (body
, 0) * sizeof (rtx
*));
2087 for (i
= 0; i
< XVECLEN (body
, 0); i
++)
2088 if (GET_CODE (XVECEXP (body
, 0, i
)) == CLOBBER
)
2090 rtx clobber
= XVECEXP (body
, 0, i
);
2091 rtx reg
= XEXP (clobber
, 0);
2092 rtx
*loc
= & XEXP (clobber
, 0);
2094 if (GET_CODE (reg
) == SUBREG
&& REG_P (SUBREG_REG (reg
)))
2096 loc
= & SUBREG_REG (reg
);
2097 reg
= SUBREG_REG (reg
);
2100 if (STACK_REG_P (reg
))
2102 clobber_reg
[n_clobbers
] = reg
;
2103 clobber_loc
[n_clobbers
] = loc
;
2109 temp_stack
= *regstack
;
2111 /* Put the input regs into the desired place in TEMP_STACK. */
2113 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
2114 if (STACK_REG_P (recog_data
.operand
[i
])
2115 && reg_class_subset_p (recog_op_alt
[i
][alt
].cl
,
2117 && recog_op_alt
[i
][alt
].cl
!= FLOAT_REGS
)
2119 /* If an operand needs to be in a particular reg in
2120 FLOAT_REGS, the constraint was either 't' or 'u'. Since
2121 these constraints are for single register classes, and
2122 reload guaranteed that operand[i] is already in that class,
2123 we can just use REGNO (recog_data.operand[i]) to know which
2124 actual reg this operand needs to be in. */
2126 int regno
= get_hard_regnum (&temp_stack
, recog_data
.operand
[i
]);
2128 gcc_assert (regno
>= 0);
2130 if ((unsigned int) regno
!= REGNO (recog_data
.operand
[i
]))
2132 /* recog_data.operand[i] is not in the right place. Find
2133 it and swap it with whatever is already in I's place.
2134 K is where recog_data.operand[i] is now. J is where it
2138 k
= temp_stack
.top
- (regno
- FIRST_STACK_REG
);
2140 - (REGNO (recog_data
.operand
[i
]) - FIRST_STACK_REG
));
2142 temp
= temp_stack
.reg
[k
];
2143 temp_stack
.reg
[k
] = temp_stack
.reg
[j
];
2144 temp_stack
.reg
[j
] = temp
;
2148 /* Emit insns before INSN to make sure the reg-stack is in the right
2151 change_stack (insn
, regstack
, &temp_stack
, EMIT_BEFORE
);
2153 /* Make the needed input register substitutions. Do death notes and
2154 clobbers too, because these are for inputs, not outputs. */
2156 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
2157 if (STACK_REG_P (recog_data
.operand
[i
]))
2159 int regnum
= get_hard_regnum (regstack
, recog_data
.operand
[i
]);
2161 gcc_assert (regnum
>= 0);
2163 replace_reg (recog_data
.operand_loc
[i
], regnum
);
2166 for (i
= 0; i
< n_notes
; i
++)
2167 if (note_kind
[i
] == REG_DEAD
)
2169 int regnum
= get_hard_regnum (regstack
, note_reg
[i
]);
2171 gcc_assert (regnum
>= 0);
2173 replace_reg (note_loc
[i
], regnum
);
2176 for (i
= 0; i
< n_clobbers
; i
++)
2178 /* It's OK for a CLOBBER to reference a reg that is not live.
2179 Don't try to replace it in that case. */
2180 int regnum
= get_hard_regnum (regstack
, clobber_reg
[i
]);
2184 /* Sigh - clobbers always have QImode. But replace_reg knows
2185 that these regs can't be MODE_INT and will assert. Just put
2186 the right reg there without calling replace_reg. */
2188 *clobber_loc
[i
] = FP_MODE_REG (regnum
, DFmode
);
2192 /* Now remove from REGSTACK any inputs that the asm implicitly popped. */
2194 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
2195 if (STACK_REG_P (recog_data
.operand
[i
]))
2197 /* An input reg is implicitly popped if it is tied to an
2198 output, or if there is a CLOBBER for it. */
2201 for (j
= 0; j
< n_clobbers
; j
++)
2202 if (operands_match_p (clobber_reg
[j
], recog_data
.operand
[i
]))
2205 if (j
< n_clobbers
|| recog_op_alt
[i
][alt
].matches
>= 0)
2207 /* recog_data.operand[i] might not be at the top of stack.
2208 But that's OK, because all we need to do is pop the
2209 right number of regs off of the top of the reg-stack.
2210 record_asm_stack_regs guaranteed that all implicitly
2211 popped regs were grouped at the top of the reg-stack. */
2213 CLEAR_HARD_REG_BIT (regstack
->reg_set
,
2214 regstack
->reg
[regstack
->top
]);
2219 /* Now add to REGSTACK any outputs that the asm implicitly pushed.
2220 Note that there isn't any need to substitute register numbers.
2221 ??? Explain why this is true. */
2223 for (i
= LAST_STACK_REG
; i
>= FIRST_STACK_REG
; i
--)
2225 /* See if there is an output for this hard reg. */
2228 for (j
= 0; j
< n_outputs
; j
++)
2229 if (STACK_REG_P (recog_data
.operand
[j
])
2230 && REGNO (recog_data
.operand
[j
]) == (unsigned) i
)
2232 regstack
->reg
[++regstack
->top
] = i
;
2233 SET_HARD_REG_BIT (regstack
->reg_set
, i
);
2238 /* Now emit a pop insn for any REG_UNUSED output, or any REG_DEAD
2239 input that the asm didn't implicitly pop. If the asm didn't
2240 implicitly pop an input reg, that reg will still be live.
2242 Note that we can't use find_regno_note here: the register numbers
2243 in the death notes have already been substituted. */
2245 for (i
= 0; i
< n_outputs
; i
++)
2246 if (STACK_REG_P (recog_data
.operand
[i
]))
2250 for (j
= 0; j
< n_notes
; j
++)
2251 if (REGNO (recog_data
.operand
[i
]) == REGNO (note_reg
[j
])
2252 && note_kind
[j
] == REG_UNUSED
)
2254 insn
= emit_pop_insn (insn
, regstack
, recog_data
.operand
[i
],
2260 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
2261 if (STACK_REG_P (recog_data
.operand
[i
]))
2265 for (j
= 0; j
< n_notes
; j
++)
2266 if (REGNO (recog_data
.operand
[i
]) == REGNO (note_reg
[j
])
2267 && note_kind
[j
] == REG_DEAD
2268 && TEST_HARD_REG_BIT (regstack
->reg_set
,
2269 REGNO (recog_data
.operand
[i
])))
2271 insn
= emit_pop_insn (insn
, regstack
, recog_data
.operand
[i
],
2278 /* Substitute stack hard reg numbers for stack virtual registers in
2279 INSN. Non-stack register numbers are not changed. REGSTACK is the
2280 current stack content. Insns may be emitted as needed to arrange the
2281 stack for the 387 based on the contents of the insn. Return whether
2282 a control flow insn was deleted in the process. */
2285 subst_stack_regs (rtx insn
, stack regstack
)
2287 rtx
*note_link
, note
;
2288 bool control_flow_insn_deleted
= false;
2293 int top
= regstack
->top
;
2295 /* If there are any floating point parameters to be passed in
2296 registers for this call, make sure they are in the right
2301 straighten_stack (PREV_INSN (insn
), regstack
);
2303 /* Now mark the arguments as dead after the call. */
2305 while (regstack
->top
>= 0)
2307 CLEAR_HARD_REG_BIT (regstack
->reg_set
, FIRST_STACK_REG
+ regstack
->top
);
2313 /* Do the actual substitution if any stack regs are mentioned.
2314 Since we only record whether entire insn mentions stack regs, and
2315 subst_stack_regs_pat only works for patterns that contain stack regs,
2316 we must check each pattern in a parallel here. A call_value_pop could
2319 if (stack_regs_mentioned (insn
))
2321 int n_operands
= asm_noperands (PATTERN (insn
));
2322 if (n_operands
>= 0)
2324 /* This insn is an `asm' with operands. Decode the operands,
2325 decide how many are inputs, and do register substitution.
2326 Any REG_UNUSED notes will be handled by subst_asm_stack_regs. */
2328 subst_asm_stack_regs (insn
, regstack
);
2329 return control_flow_insn_deleted
;
2332 if (GET_CODE (PATTERN (insn
)) == PARALLEL
)
2333 for (i
= 0; i
< XVECLEN (PATTERN (insn
), 0); i
++)
2335 if (stack_regs_mentioned_p (XVECEXP (PATTERN (insn
), 0, i
)))
2337 if (GET_CODE (XVECEXP (PATTERN (insn
), 0, i
)) == CLOBBER
)
2338 XVECEXP (PATTERN (insn
), 0, i
)
2339 = shallow_copy_rtx (XVECEXP (PATTERN (insn
), 0, i
));
2340 control_flow_insn_deleted
2341 |= subst_stack_regs_pat (insn
, regstack
,
2342 XVECEXP (PATTERN (insn
), 0, i
));
2346 control_flow_insn_deleted
2347 |= subst_stack_regs_pat (insn
, regstack
, PATTERN (insn
));
2350 /* subst_stack_regs_pat may have deleted a no-op insn. If so, any
2351 REG_UNUSED will already have been dealt with, so just return. */
2353 if (NOTE_P (insn
) || INSN_DELETED_P (insn
))
2354 return control_flow_insn_deleted
;
2356 /* If there is a REG_UNUSED note on a stack register on this insn,
2357 the indicated reg must be popped. The REG_UNUSED note is removed,
2358 since the form of the newly emitted pop insn references the reg,
2359 making it no longer `unset'. */
2361 note_link
= ®_NOTES (insn
);
2362 for (note
= *note_link
; note
; note
= XEXP (note
, 1))
2363 if (REG_NOTE_KIND (note
) == REG_UNUSED
&& STACK_REG_P (XEXP (note
, 0)))
2365 *note_link
= XEXP (note
, 1);
2366 insn
= emit_pop_insn (insn
, regstack
, XEXP (note
, 0), EMIT_AFTER
);
2369 note_link
= &XEXP (note
, 1);
2371 return control_flow_insn_deleted
;
2374 /* Change the organization of the stack so that it fits a new basic
2375 block. Some registers might have to be popped, but there can never be
2376 a register live in the new block that is not now live.
2378 Insert any needed insns before or after INSN, as indicated by
2379 WHERE. OLD is the original stack layout, and NEW is the desired
2380 form. OLD is updated to reflect the code emitted, i.e., it will be
2381 the same as NEW upon return.
2383 This function will not preserve block_end[]. But that information
2384 is no longer needed once this has executed. */
2387 change_stack (rtx insn
, stack old
, stack
new, enum emit_where where
)
2392 /* We will be inserting new insns "backwards". If we are to insert
2393 after INSN, find the next insn, and insert before it. */
2395 if (where
== EMIT_AFTER
)
2397 if (current_block
&& BB_END (current_block
) == insn
)
2399 insn
= NEXT_INSN (insn
);
2402 /* Pop any registers that are not needed in the new block. */
2404 /* If the destination block's stack already has a specified layout
2405 and contains two or more registers, use a more intelligent algorithm
2406 to pop registers that minimizes the number number of fxchs below. */
2409 bool slots
[REG_STACK_SIZE
];
2410 int pops
[REG_STACK_SIZE
];
2411 int next
, dest
, topsrc
;
2413 /* First pass to determine the free slots. */
2414 for (reg
= 0; reg
<= new->top
; reg
++)
2415 slots
[reg
] = TEST_HARD_REG_BIT (new->reg_set
, old
->reg
[reg
]);
2417 /* Second pass to allocate preferred slots. */
2419 for (reg
= old
->top
; reg
> new->top
; reg
--)
2420 if (TEST_HARD_REG_BIT (new->reg_set
, old
->reg
[reg
]))
2423 for (next
= 0; next
<= new->top
; next
++)
2424 if (!slots
[next
] && new->reg
[next
] == old
->reg
[reg
])
2426 /* If this is a preference for the new top of stack, record
2427 the fact by remembering it's old->reg in topsrc. */
2428 if (next
== new->top
)
2439 /* Intentionally, avoid placing the top of stack in it's correct
2440 location, if we still need to permute the stack below and we
2441 can usefully place it somewhere else. This is the case if any
2442 slot is still unallocated, in which case we should place the
2443 top of stack there. */
2445 for (reg
= 0; reg
< new->top
; reg
++)
2449 slots
[new->top
] = false;
2454 /* Third pass allocates remaining slots and emits pop insns. */
2456 for (reg
= old
->top
; reg
> new->top
; reg
--)
2461 /* Find next free slot. */
2466 emit_pop_insn (insn
, old
, FP_MODE_REG (old
->reg
[dest
], DFmode
),
2472 /* The following loop attempts to maximize the number of times we
2473 pop the top of the stack, as this permits the use of the faster
2474 ffreep instruction on platforms that support it. */
2478 for (reg
= 0; reg
<= old
->top
; reg
++)
2479 if (TEST_HARD_REG_BIT (new->reg_set
, old
->reg
[reg
]))
2483 while (old
->top
>= live
)
2484 if (TEST_HARD_REG_BIT (new->reg_set
, old
->reg
[old
->top
]))
2486 while (TEST_HARD_REG_BIT (new->reg_set
, old
->reg
[next
]))
2488 emit_pop_insn (insn
, old
, FP_MODE_REG (old
->reg
[next
], DFmode
),
2492 emit_pop_insn (insn
, old
, FP_MODE_REG (old
->reg
[old
->top
], DFmode
),
2498 /* If the new block has never been processed, then it can inherit
2499 the old stack order. */
2501 new->top
= old
->top
;
2502 memcpy (new->reg
, old
->reg
, sizeof (new->reg
));
2506 /* This block has been entered before, and we must match the
2507 previously selected stack order. */
2509 /* By now, the only difference should be the order of the stack,
2510 not their depth or liveliness. */
2512 GO_IF_HARD_REG_EQUAL (old
->reg_set
, new->reg_set
, win
);
2515 gcc_assert (old
->top
== new->top
);
2517 /* If the stack is not empty (new->top != -1), loop here emitting
2518 swaps until the stack is correct.
2520 The worst case number of swaps emitted is N + 2, where N is the
2521 depth of the stack. In some cases, the reg at the top of
2522 stack may be correct, but swapped anyway in order to fix
2523 other regs. But since we never swap any other reg away from
2524 its correct slot, this algorithm will converge. */
2529 /* Swap the reg at top of stack into the position it is
2530 supposed to be in, until the correct top of stack appears. */
2532 while (old
->reg
[old
->top
] != new->reg
[new->top
])
2534 for (reg
= new->top
; reg
>= 0; reg
--)
2535 if (new->reg
[reg
] == old
->reg
[old
->top
])
2538 gcc_assert (reg
!= -1);
2540 emit_swap_insn (insn
, old
,
2541 FP_MODE_REG (old
->reg
[reg
], DFmode
));
2544 /* See if any regs remain incorrect. If so, bring an
2545 incorrect reg to the top of stack, and let the while loop
2548 for (reg
= new->top
; reg
>= 0; reg
--)
2549 if (new->reg
[reg
] != old
->reg
[reg
])
2551 emit_swap_insn (insn
, old
,
2552 FP_MODE_REG (old
->reg
[reg
], DFmode
));
2557 /* At this point there must be no differences. */
2559 for (reg
= old
->top
; reg
>= 0; reg
--)
2560 gcc_assert (old
->reg
[reg
] == new->reg
[reg
]);
2564 BB_END (current_block
) = PREV_INSN (insn
);
2567 /* Print stack configuration. */
2570 print_stack (FILE *file
, stack s
)
2576 fprintf (file
, "uninitialized\n");
2577 else if (s
->top
== -1)
2578 fprintf (file
, "empty\n");
2583 for (i
= 0; i
<= s
->top
; ++i
)
2584 fprintf (file
, "%d ", s
->reg
[i
]);
2585 fputs ("]\n", file
);
2589 /* This function was doing life analysis. We now let the regular live
2590 code do it's job, so we only need to check some extra invariants
2591 that reg-stack expects. Primary among these being that all registers
2592 are initialized before use.
2594 The function returns true when code was emitted to CFG edges and
2595 commit_edge_insertions needs to be called. */
2598 convert_regs_entry (void)
2605 FOR_EACH_BB_REVERSE (block
)
2607 block_info bi
= BLOCK_INFO (block
);
2610 /* Set current register status at last instruction `uninitialized'. */
2611 bi
->stack_in
.top
= -2;
2613 /* Copy live_at_end and live_at_start into temporaries. */
2614 for (reg
= FIRST_STACK_REG
; reg
<= LAST_STACK_REG
; reg
++)
2616 if (REGNO_REG_SET_P (block
->global_live_at_end
, reg
))
2617 SET_HARD_REG_BIT (bi
->out_reg_set
, reg
);
2618 if (REGNO_REG_SET_P (block
->global_live_at_start
, reg
))
2619 SET_HARD_REG_BIT (bi
->stack_in
.reg_set
, reg
);
2623 /* Load something into each stack register live at function entry.
2624 Such live registers can be caused by uninitialized variables or
2625 functions not returning values on all paths. In order to keep
2626 the push/pop code happy, and to not scrog the register stack, we
2627 must put something in these registers. Use a QNaN.
2629 Note that we are inserting converted code here. This code is
2630 never seen by the convert_regs pass. */
2632 FOR_EACH_EDGE (e
, ei
, ENTRY_BLOCK_PTR
->succs
)
2634 basic_block block
= e
->dest
;
2635 block_info bi
= BLOCK_INFO (block
);
2638 for (reg
= LAST_STACK_REG
; reg
>= FIRST_STACK_REG
; --reg
)
2639 if (TEST_HARD_REG_BIT (bi
->stack_in
.reg_set
, reg
))
2643 bi
->stack_in
.reg
[++top
] = reg
;
2645 init
= gen_rtx_SET (VOIDmode
,
2646 FP_MODE_REG (FIRST_STACK_REG
, SFmode
),
2648 insert_insn_on_edge (init
, e
);
2652 bi
->stack_in
.top
= top
;
2658 /* Construct the desired stack for function exit. This will either
2659 be `empty', or the function return value at top-of-stack. */
2662 convert_regs_exit (void)
2664 int value_reg_low
, value_reg_high
;
2668 retvalue
= stack_result (current_function_decl
);
2669 value_reg_low
= value_reg_high
= -1;
2672 value_reg_low
= REGNO (retvalue
);
2673 value_reg_high
= value_reg_low
2674 + hard_regno_nregs
[value_reg_low
][GET_MODE (retvalue
)] - 1;
2677 output_stack
= &BLOCK_INFO (EXIT_BLOCK_PTR
)->stack_in
;
2678 if (value_reg_low
== -1)
2679 output_stack
->top
= -1;
2684 output_stack
->top
= value_reg_high
- value_reg_low
;
2685 for (reg
= value_reg_low
; reg
<= value_reg_high
; ++reg
)
2687 output_stack
->reg
[value_reg_high
- reg
] = reg
;
2688 SET_HARD_REG_BIT (output_stack
->reg_set
, reg
);
2693 /* Adjust the stack of this block on exit to match the stack of the
2694 target block, or copy stack info into the stack of the successor
2695 of the successor hasn't been processed yet. */
2697 compensate_edge (edge e
, FILE *file
)
2699 basic_block block
= e
->src
, target
= e
->dest
;
2700 block_info bi
= BLOCK_INFO (block
);
2701 struct stack_def regstack
, tmpstack
;
2702 stack target_stack
= &BLOCK_INFO (target
)->stack_in
;
2705 current_block
= block
;
2706 regstack
= bi
->stack_out
;
2708 fprintf (file
, "Edge %d->%d: ", block
->index
, target
->index
);
2710 if (target_stack
->top
== -2)
2712 /* The target block hasn't had a stack order selected.
2713 We need merely ensure that no pops are needed. */
2714 for (reg
= regstack
.top
; reg
>= 0; --reg
)
2715 if (!TEST_HARD_REG_BIT (target_stack
->reg_set
, regstack
.reg
[reg
]))
2721 fprintf (file
, "new block; copying stack position\n");
2723 /* change_stack kills values in regstack. */
2724 tmpstack
= regstack
;
2726 change_stack (BB_END (block
), &tmpstack
, target_stack
, EMIT_AFTER
);
2731 fprintf (file
, "new block; pops needed\n");
2735 if (target_stack
->top
== regstack
.top
)
2737 for (reg
= target_stack
->top
; reg
>= 0; --reg
)
2738 if (target_stack
->reg
[reg
] != regstack
.reg
[reg
])
2744 fprintf (file
, "no changes needed\n");
2751 fprintf (file
, "correcting stack to ");
2752 print_stack (file
, target_stack
);
2756 /* Care for non-call EH edges specially. The normal return path have
2757 values in registers. These will be popped en masse by the unwind
2759 if ((e
->flags
& (EDGE_EH
| EDGE_ABNORMAL_CALL
)) == EDGE_EH
)
2760 target_stack
->top
= -1;
2762 /* Other calls may appear to have values live in st(0), but the
2763 abnormal return path will not have actually loaded the values. */
2764 else if (e
->flags
& EDGE_ABNORMAL_CALL
)
2766 /* Assert that the lifetimes are as we expect -- one value
2767 live at st(0) on the end of the source block, and no
2768 values live at the beginning of the destination block. */
2771 CLEAR_HARD_REG_SET (tmp
);
2772 GO_IF_HARD_REG_EQUAL (target_stack
->reg_set
, tmp
, eh1
);
2776 /* We are sure that there is st(0) live, otherwise we won't compensate.
2777 For complex return values, we may have st(1) live as well. */
2778 SET_HARD_REG_BIT (tmp
, FIRST_STACK_REG
);
2779 if (TEST_HARD_REG_BIT (regstack
.reg_set
, FIRST_STACK_REG
+ 1))
2780 SET_HARD_REG_BIT (tmp
, FIRST_STACK_REG
+ 1);
2781 GO_IF_HARD_REG_EQUAL (regstack
.reg_set
, tmp
, eh2
);
2785 target_stack
->top
= -1;
2788 /* It is better to output directly to the end of the block
2789 instead of to the edge, because emit_swap can do minimal
2790 insn scheduling. We can do this when there is only one
2791 edge out, and it is not abnormal. */
2792 else if (EDGE_COUNT (block
->succs
) == 1 && !(e
->flags
& EDGE_ABNORMAL
))
2794 /* change_stack kills values in regstack. */
2795 tmpstack
= regstack
;
2797 change_stack (BB_END (block
), &tmpstack
, target_stack
,
2798 (JUMP_P (BB_END (block
))
2799 ? EMIT_BEFORE
: EMIT_AFTER
));
2805 /* We don't support abnormal edges. Global takes care to
2806 avoid any live register across them, so we should never
2807 have to insert instructions on such edges. */
2808 gcc_assert (!(e
->flags
& EDGE_ABNORMAL
));
2810 current_block
= NULL
;
2813 /* ??? change_stack needs some point to emit insns after. */
2814 after
= emit_note (NOTE_INSN_DELETED
);
2816 tmpstack
= regstack
;
2817 change_stack (after
, &tmpstack
, target_stack
, EMIT_BEFORE
);
2822 insert_insn_on_edge (seq
, e
);
2828 /* Convert stack register references in one block. */
2831 convert_regs_1 (FILE *file
, basic_block block
)
2833 struct stack_def regstack
;
2834 block_info bi
= BLOCK_INFO (block
);
2837 edge e
, beste
= NULL
;
2838 bool control_flow_insn_deleted
= false;
2842 any_malformed_asm
= false;
2844 /* Find the edge we will copy stack from. It should be the most frequent
2845 one as it will get cheapest after compensation code is generated,
2846 if multiple such exists, take one with largest count, prefer critical
2847 one (as splitting critical edges is more expensive), or one with lowest
2848 index, to avoid random changes with different orders of the edges. */
2849 FOR_EACH_EDGE (e
, ei
, block
->preds
)
2851 if (e
->flags
& EDGE_DFS_BACK
)
2855 else if (EDGE_FREQUENCY (beste
) < EDGE_FREQUENCY (e
))
2857 else if (EDGE_FREQUENCY (beste
) > EDGE_FREQUENCY (e
))
2859 else if (beste
->count
< e
->count
)
2861 else if (beste
->count
> e
->count
)
2863 else if ((EDGE_CRITICAL_P (e
) != 0)
2864 != (EDGE_CRITICAL_P (beste
) != 0))
2866 if (EDGE_CRITICAL_P (e
))
2869 else if (e
->src
->index
< beste
->src
->index
)
2873 /* Initialize stack at block entry. */
2874 if (bi
->stack_in
.top
== -2)
2877 inserted
|= compensate_edge (beste
, file
);
2880 /* No predecessors. Create an arbitrary input stack. */
2883 bi
->stack_in
.top
= -1;
2884 for (reg
= LAST_STACK_REG
; reg
>= FIRST_STACK_REG
; --reg
)
2885 if (TEST_HARD_REG_BIT (bi
->stack_in
.reg_set
, reg
))
2886 bi
->stack_in
.reg
[++bi
->stack_in
.top
] = reg
;
2890 /* Entry blocks do have stack already initialized. */
2893 current_block
= block
;
2897 fprintf (file
, "\nBasic block %d\nInput stack: ", block
->index
);
2898 print_stack (file
, &bi
->stack_in
);
2901 /* Process all insns in this block. Keep track of NEXT so that we
2902 don't process insns emitted while substituting in INSN. */
2903 next
= BB_HEAD (block
);
2904 regstack
= bi
->stack_in
;
2908 next
= NEXT_INSN (insn
);
2910 /* Ensure we have not missed a block boundary. */
2912 if (insn
== BB_END (block
))
2915 /* Don't bother processing unless there is a stack reg
2916 mentioned or if it's a CALL_INSN. */
2917 if (stack_regs_mentioned (insn
)
2922 fprintf (file
, " insn %d input stack: ",
2924 print_stack (file
, ®stack
);
2926 control_flow_insn_deleted
|= subst_stack_regs (insn
, ®stack
);
2933 fprintf (file
, "Expected live registers [");
2934 for (reg
= FIRST_STACK_REG
; reg
<= LAST_STACK_REG
; ++reg
)
2935 if (TEST_HARD_REG_BIT (bi
->out_reg_set
, reg
))
2936 fprintf (file
, " %d", reg
);
2937 fprintf (file
, " ]\nOutput stack: ");
2938 print_stack (file
, ®stack
);
2941 insn
= BB_END (block
);
2943 insn
= PREV_INSN (insn
);
2945 /* If the function is declared to return a value, but it returns one
2946 in only some cases, some registers might come live here. Emit
2947 necessary moves for them. */
2949 for (reg
= FIRST_STACK_REG
; reg
<= LAST_STACK_REG
; ++reg
)
2951 if (TEST_HARD_REG_BIT (bi
->out_reg_set
, reg
)
2952 && ! TEST_HARD_REG_BIT (regstack
.reg_set
, reg
))
2957 fprintf (file
, "Emitting insn initializing reg %d\n", reg
);
2959 set
= gen_rtx_SET (VOIDmode
, FP_MODE_REG (reg
, SFmode
), not_a_num
);
2960 insn
= emit_insn_after (set
, insn
);
2961 control_flow_insn_deleted
|= subst_stack_regs (insn
, ®stack
);
2965 /* Amongst the insns possibly deleted during the substitution process above,
2966 might have been the only trapping insn in the block. We purge the now
2967 possibly dead EH edges here to avoid an ICE from fixup_abnormal_edges,
2968 called at the end of convert_regs. The order in which we process the
2969 blocks ensures that we never delete an already processed edge.
2971 Note that, at this point, the CFG may have been damaged by the emission
2972 of instructions after an abnormal call, which moves the basic block end
2973 (and is the reason why we call fixup_abnormal_edges later). So we must
2974 be sure that the trapping insn has been deleted before trying to purge
2975 dead edges, otherwise we risk purging valid edges.
2977 ??? We are normally supposed not to delete trapping insns, so we pretend
2978 that the insns deleted above don't actually trap. It would have been
2979 better to detect this earlier and avoid creating the EH edge in the first
2980 place, still, but we don't have enough information at that time. */
2982 if (control_flow_insn_deleted
)
2983 purge_dead_edges (block
);
2985 /* Something failed if the stack lives don't match. If we had malformed
2986 asms, we zapped the instruction itself, but that didn't produce the
2987 same pattern of register kills as before. */
2988 GO_IF_HARD_REG_EQUAL (regstack
.reg_set
, bi
->out_reg_set
, win
);
2989 gcc_assert (any_malformed_asm
);
2991 bi
->stack_out
= regstack
;
2993 /* Compensate the back edges, as those wasn't visited yet. */
2994 FOR_EACH_EDGE (e
, ei
, block
->succs
)
2996 if (e
->flags
& EDGE_DFS_BACK
2997 || (e
->dest
== EXIT_BLOCK_PTR
))
2999 gcc_assert (BLOCK_INFO (e
->dest
)->done
3000 || e
->dest
== block
);
3001 inserted
|= compensate_edge (e
, file
);
3004 FOR_EACH_EDGE (e
, ei
, block
->preds
)
3006 if (e
!= beste
&& !(e
->flags
& EDGE_DFS_BACK
)
3007 && e
->src
!= ENTRY_BLOCK_PTR
)
3009 gcc_assert (BLOCK_INFO (e
->src
)->done
);
3010 inserted
|= compensate_edge (e
, file
);
3017 /* Convert registers in all blocks reachable from BLOCK. */
3020 convert_regs_2 (FILE *file
, basic_block block
)
3022 basic_block
*stack
, *sp
;
3025 /* We process the blocks in a top-down manner, in a way such that one block
3026 is only processed after all its predecessors. The number of predecessors
3027 of every block has already been computed. */
3029 stack
= xmalloc (sizeof (*stack
) * n_basic_blocks
);
3042 /* Processing BLOCK is achieved by convert_regs_1, which may purge
3043 some dead EH outgoing edge after the deletion of the trapping
3044 insn inside the block. Since the number of predecessors of
3045 BLOCK's successors was computed based on the initial edge set,
3046 we check the necessity to process some of these successors
3047 before such an edge deletion may happen. However, there is
3048 a pitfall: if BLOCK is the only predecessor of a successor and
3049 the edge between them happens to be deleted, the successor
3050 becomes unreachable and should not be processed. The problem
3051 is that there is no way to preventively detect this case so we
3052 stack the successor in all cases and hand over the task of
3053 fixing up the discrepancy to convert_regs_1. */
3055 FOR_EACH_EDGE (e
, ei
, block
->succs
)
3056 if (! (e
->flags
& EDGE_DFS_BACK
))
3058 BLOCK_INFO (e
->dest
)->predecessors
--;
3059 if (!BLOCK_INFO (e
->dest
)->predecessors
)
3063 inserted
|= convert_regs_1 (file
, block
);
3064 BLOCK_INFO (block
)->done
= 1;
3066 while (sp
!= stack
);
3073 /* Traverse all basic blocks in a function, converting the register
3074 references in each insn from the "flat" register file that gcc uses,
3075 to the stack-like registers the 387 uses. */
3078 convert_regs (FILE *file
)
3085 /* Initialize uninitialized registers on function entry. */
3086 inserted
= convert_regs_entry ();
3088 /* Construct the desired stack for function exit. */
3089 convert_regs_exit ();
3090 BLOCK_INFO (EXIT_BLOCK_PTR
)->done
= 1;
3092 /* ??? Future: process inner loops first, and give them arbitrary
3093 initial stacks which emit_swap_insn can modify. This ought to
3094 prevent double fxch that often appears at the head of a loop. */
3096 /* Process all blocks reachable from all entry points. */
3097 FOR_EACH_EDGE (e
, ei
, ENTRY_BLOCK_PTR
->succs
)
3098 inserted
|= convert_regs_2 (file
, e
->dest
);
3100 /* ??? Process all unreachable blocks. Though there's no excuse
3101 for keeping these even when not optimizing. */
3104 block_info bi
= BLOCK_INFO (b
);
3107 inserted
|= convert_regs_2 (file
, b
);
3109 clear_aux_for_blocks ();
3111 fixup_abnormal_edges ();
3113 commit_edge_insertions ();
3120 #endif /* STACK_REGS */
3122 #include "gt-reg-stack.h"