1 /* Register to Stack convert for GNU compiler.
2 Copyright (C) 1992-2014 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3, or (at your option)
11 GCC is distributed in the hope that it will be useful, but WITHOUT
12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
13 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
14 License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
20 /* This pass converts stack-like registers from the "flat register
21 file" model that gcc uses, to a stack convention that the 387 uses.
23 * The form of the input:
25 On input, the function consists of insn that have had their
26 registers fully allocated to a set of "virtual" registers. Note that
27 the word "virtual" is used differently here than elsewhere in gcc: for
28 each virtual stack reg, there is a hard reg, but the mapping between
29 them is not known until this pass is run. On output, hard register
30 numbers have been substituted, and various pop and exchange insns have
31 been emitted. The hard register numbers and the virtual register
32 numbers completely overlap - before this pass, all stack register
33 numbers are virtual, and afterward they are all hard.
35 The virtual registers can be manipulated normally by gcc, and their
36 semantics are the same as for normal registers. After the hard
37 register numbers are substituted, the semantics of an insn containing
38 stack-like regs are not the same as for an insn with normal regs: for
39 instance, it is not safe to delete an insn that appears to be a no-op
40 move. In general, no insn containing hard regs should be changed
41 after this pass is done.
43 * The form of the output:
45 After this pass, hard register numbers represent the distance from
46 the current top of stack to the desired register. A reference to
47 FIRST_STACK_REG references the top of stack, FIRST_STACK_REG + 1,
48 represents the register just below that, and so forth. Also, REG_DEAD
49 notes indicate whether or not a stack register should be popped.
51 A "swap" insn looks like a parallel of two patterns, where each
52 pattern is a SET: one sets A to B, the other B to A.
54 A "push" or "load" insn is a SET whose SET_DEST is FIRST_STACK_REG
55 and whose SET_DEST is REG or MEM. Any other SET_DEST, such as PLUS,
56 will replace the existing stack top, not push a new value.
58 A store insn is a SET whose SET_DEST is FIRST_STACK_REG, and whose
59 SET_SRC is REG or MEM.
61 The case where the SET_SRC and SET_DEST are both FIRST_STACK_REG
62 appears ambiguous. As a special case, the presence of a REG_DEAD note
63 for FIRST_STACK_REG differentiates between a load insn and a pop.
65 If a REG_DEAD is present, the insn represents a "pop" that discards
66 the top of the register stack. If there is no REG_DEAD note, then the
67 insn represents a "dup" or a push of the current top of stack onto the
72 Existing REG_DEAD and REG_UNUSED notes for stack registers are
73 deleted and recreated from scratch. REG_DEAD is never created for a
74 SET_DEST, only REG_UNUSED.
78 There are several rules on the usage of stack-like regs in
79 asm_operands insns. These rules apply only to the operands that are
82 1. Given a set of input regs that die in an asm_operands, it is
83 necessary to know which are implicitly popped by the asm, and
84 which must be explicitly popped by gcc.
86 An input reg that is implicitly popped by the asm must be
87 explicitly clobbered, unless it is constrained to match an
90 2. For any input reg that is implicitly popped by an asm, it is
91 necessary to know how to adjust the stack to compensate for the pop.
92 If any non-popped input is closer to the top of the reg-stack than
93 the implicitly popped reg, it would not be possible to know what the
94 stack looked like - it's not clear how the rest of the stack "slides
97 All implicitly popped input regs must be closer to the top of
98 the reg-stack than any input that is not implicitly popped.
100 3. It is possible that if an input dies in an insn, reload might
101 use the input reg for an output reload. Consider this example:
103 asm ("foo" : "=t" (a) : "f" (b));
105 This asm says that input B is not popped by the asm, and that
106 the asm pushes a result onto the reg-stack, i.e., the stack is one
107 deeper after the asm than it was before. But, it is possible that
108 reload will think that it can use the same reg for both the input and
109 the output, if input B dies in this insn.
111 If any input operand uses the "f" constraint, all output reg
112 constraints must use the "&" earlyclobber.
114 The asm above would be written as
116 asm ("foo" : "=&t" (a) : "f" (b));
118 4. Some operands need to be in particular places on the stack. All
119 output operands fall in this category - there is no other way to
120 know which regs the outputs appear in unless the user indicates
121 this in the constraints.
123 Output operands must specifically indicate which reg an output
124 appears in after an asm. "=f" is not allowed: the operand
125 constraints must select a class with a single reg.
127 5. Output operands may not be "inserted" between existing stack regs.
128 Since no 387 opcode uses a read/write operand, all output operands
129 are dead before the asm_operands, and are pushed by the asm_operands.
130 It makes no sense to push anywhere but the top of the reg-stack.
132 Output operands must start at the top of the reg-stack: output
133 operands may not "skip" a reg.
135 6. Some asm statements may need extra stack space for internal
136 calculations. This can be guaranteed by clobbering stack registers
137 unrelated to the inputs and outputs.
139 Here are a couple of reasonable asms to want to write. This asm
140 takes one input, which is internally popped, and produces two outputs.
142 asm ("fsincos" : "=t" (cos), "=u" (sin) : "0" (inp));
144 This asm takes two inputs, which are popped by the fyl2xp1 opcode,
145 and replaces them with one output. The user must code the "st(1)"
146 clobber for reg-stack.c to know that fyl2xp1 pops both inputs.
148 asm ("fyl2xp1" : "=t" (result) : "0" (x), "u" (y) : "st(1)");
154 #include "coretypes.h"
158 #include "rtl-error.h"
161 #include "hash-set.h"
163 #include "machmode.h"
164 #include "hard-reg-set.h"
166 #include "function.h"
167 #include "insn-config.h"
171 #include "basic-block.h"
174 #include "tree-pass.h"
177 #include "emit-rtl.h" /* FIXME: Can go away once crtl is moved to rtl.h. */
178 #include "rtl-iter.h"
182 /* We use this array to cache info about insns, because otherwise we
183 spend too much time in stack_regs_mentioned_p.
185 Indexed by insn UIDs. A value of zero is uninitialized, one indicates
186 the insn uses stack registers, two indicates the insn does not use
188 static vec
<char> stack_regs_mentioned_data
;
190 #define REG_STACK_SIZE (LAST_STACK_REG - FIRST_STACK_REG + 1)
192 int regstack_completed
= 0;
194 /* This is the basic stack record. TOP is an index into REG[] such
195 that REG[TOP] is the top of stack. If TOP is -1 the stack is empty.
197 If TOP is -2, REG[] is not yet initialized. Stack initialization
198 consists of placing each live reg in array `reg' and setting `top'
201 REG_SET indicates which registers are live. */
203 typedef struct stack_def
205 int top
; /* index to top stack element */
206 HARD_REG_SET reg_set
; /* set of live registers */
207 unsigned char reg
[REG_STACK_SIZE
];/* register - stack mapping */
210 /* This is used to carry information about basic blocks. It is
211 attached to the AUX field of the standard CFG block. */
213 typedef struct block_info_def
215 struct stack_def stack_in
; /* Input stack configuration. */
216 struct stack_def stack_out
; /* Output stack configuration. */
217 HARD_REG_SET out_reg_set
; /* Stack regs live on output. */
218 int done
; /* True if block already converted. */
219 int predecessors
; /* Number of predecessors that need
223 #define BLOCK_INFO(B) ((block_info) (B)->aux)
225 /* Passed to change_stack to indicate where to emit insns. */
232 /* The block we're currently working on. */
233 static basic_block current_block
;
235 /* In the current_block, whether we're processing the first register
236 stack or call instruction, i.e. the regstack is currently the
237 same as BLOCK_INFO(current_block)->stack_in. */
238 static bool starting_stack_p
;
240 /* This is the register file for all register after conversion. */
242 FP_mode_reg
[LAST_STACK_REG
+1-FIRST_STACK_REG
][(int) MAX_MACHINE_MODE
];
244 #define FP_MODE_REG(regno,mode) \
245 (FP_mode_reg[(regno)-FIRST_STACK_REG][(int) (mode)])
247 /* Used to initialize uninitialized registers. */
248 static rtx not_a_num
;
250 /* Forward declarations */
252 static int stack_regs_mentioned_p (const_rtx pat
);
253 static void pop_stack (stack_ptr
, int);
254 static rtx
*get_true_reg (rtx
*);
256 static int check_asm_stack_operands (rtx_insn
*);
257 static void get_asm_operands_in_out (rtx
, int *, int *);
258 static rtx
stack_result (tree
);
259 static void replace_reg (rtx
*, int);
260 static void remove_regno_note (rtx_insn
*, enum reg_note
, unsigned int);
261 static int get_hard_regnum (stack_ptr
, rtx
);
262 static rtx_insn
*emit_pop_insn (rtx_insn
*, stack_ptr
, rtx
, enum emit_where
);
263 static void swap_to_top (rtx_insn
*, stack_ptr
, rtx
, rtx
);
264 static bool move_for_stack_reg (rtx_insn
*, stack_ptr
, rtx
);
265 static bool move_nan_for_stack_reg (rtx_insn
*, stack_ptr
, rtx
);
266 static int swap_rtx_condition_1 (rtx
);
267 static int swap_rtx_condition (rtx_insn
*);
268 static void compare_for_stack_reg (rtx_insn
*, stack_ptr
, rtx
);
269 static bool subst_stack_regs_pat (rtx_insn
*, stack_ptr
, rtx
);
270 static void subst_asm_stack_regs (rtx_insn
*, stack_ptr
);
271 static bool subst_stack_regs (rtx_insn
*, stack_ptr
);
272 static void change_stack (rtx_insn
*, stack_ptr
, stack_ptr
, enum emit_where
);
273 static void print_stack (FILE *, stack_ptr
);
274 static rtx_insn
*next_flags_user (rtx_insn
*);
276 /* Return nonzero if any stack register is mentioned somewhere within PAT. */
279 stack_regs_mentioned_p (const_rtx pat
)
284 if (STACK_REG_P (pat
))
287 fmt
= GET_RTX_FORMAT (GET_CODE (pat
));
288 for (i
= GET_RTX_LENGTH (GET_CODE (pat
)) - 1; i
>= 0; i
--)
294 for (j
= XVECLEN (pat
, i
) - 1; j
>= 0; j
--)
295 if (stack_regs_mentioned_p (XVECEXP (pat
, i
, j
)))
298 else if (fmt
[i
] == 'e' && stack_regs_mentioned_p (XEXP (pat
, i
)))
305 /* Return nonzero if INSN mentions stacked registers, else return zero. */
308 stack_regs_mentioned (const_rtx insn
)
310 unsigned int uid
, max
;
313 if (! INSN_P (insn
) || !stack_regs_mentioned_data
.exists ())
316 uid
= INSN_UID (insn
);
317 max
= stack_regs_mentioned_data
.length ();
320 /* Allocate some extra size to avoid too many reallocs, but
321 do not grow too quickly. */
322 max
= uid
+ uid
/ 20 + 1;
323 stack_regs_mentioned_data
.safe_grow_cleared (max
);
326 test
= stack_regs_mentioned_data
[uid
];
329 /* This insn has yet to be examined. Do so now. */
330 test
= stack_regs_mentioned_p (PATTERN (insn
)) ? 1 : 2;
331 stack_regs_mentioned_data
[uid
] = test
;
337 static rtx ix86_flags_rtx
;
340 next_flags_user (rtx_insn
*insn
)
342 /* Search forward looking for the first use of this value.
343 Stop at block boundaries. */
345 while (insn
!= BB_END (current_block
))
347 insn
= NEXT_INSN (insn
);
349 if (INSN_P (insn
) && reg_mentioned_p (ix86_flags_rtx
, PATTERN (insn
)))
358 /* Reorganize the stack into ascending numbers, before this insn. */
361 straighten_stack (rtx_insn
*insn
, stack_ptr regstack
)
363 struct stack_def temp_stack
;
366 /* If there is only a single register on the stack, then the stack is
367 already in increasing order and no reorganization is needed.
369 Similarly if the stack is empty. */
370 if (regstack
->top
<= 0)
373 COPY_HARD_REG_SET (temp_stack
.reg_set
, regstack
->reg_set
);
375 for (top
= temp_stack
.top
= regstack
->top
; top
>= 0; top
--)
376 temp_stack
.reg
[top
] = FIRST_STACK_REG
+ temp_stack
.top
- top
;
378 change_stack (insn
, regstack
, &temp_stack
, EMIT_BEFORE
);
381 /* Pop a register from the stack. */
384 pop_stack (stack_ptr regstack
, int regno
)
386 int top
= regstack
->top
;
388 CLEAR_HARD_REG_BIT (regstack
->reg_set
, regno
);
390 /* If regno was not at the top of stack then adjust stack. */
391 if (regstack
->reg
[top
] != regno
)
394 for (i
= regstack
->top
; i
>= 0; i
--)
395 if (regstack
->reg
[i
] == regno
)
398 for (j
= i
; j
< top
; j
++)
399 regstack
->reg
[j
] = regstack
->reg
[j
+ 1];
405 /* Return a pointer to the REG expression within PAT. If PAT is not a
406 REG, possible enclosed by a conversion rtx, return the inner part of
407 PAT that stopped the search. */
410 get_true_reg (rtx
*pat
)
413 switch (GET_CODE (*pat
))
416 /* Eliminate FP subregister accesses in favor of the
417 actual FP register in use. */
420 if (STACK_REG_P (subreg
= SUBREG_REG (*pat
)))
422 int regno_off
= subreg_regno_offset (REGNO (subreg
),
426 *pat
= FP_MODE_REG (REGNO (subreg
) + regno_off
,
434 pat
= & XEXP (*pat
, 0);
438 if (XINT (*pat
, 1) == UNSPEC_TRUNC_NOOP
439 || XINT (*pat
, 1) == UNSPEC_LDA
)
440 pat
= & XVECEXP (*pat
, 0, 0);
444 if (!flag_unsafe_math_optimizations
)
446 pat
= & XEXP (*pat
, 0);
454 /* Set if we find any malformed asms in a block. */
455 static bool any_malformed_asm
;
457 /* There are many rules that an asm statement for stack-like regs must
458 follow. Those rules are explained at the top of this file: the rule
459 numbers below refer to that explanation. */
462 check_asm_stack_operands (rtx_insn
*insn
)
466 int malformed_asm
= 0;
467 rtx body
= PATTERN (insn
);
469 char reg_used_as_output
[FIRST_PSEUDO_REGISTER
];
470 char implicitly_dies
[FIRST_PSEUDO_REGISTER
];
472 rtx
*clobber_reg
= 0;
473 int n_inputs
, n_outputs
;
475 /* Find out what the constraints require. If no constraint
476 alternative matches, this asm is malformed. */
477 extract_constrain_insn (insn
);
479 preprocess_constraints (insn
);
481 get_asm_operands_in_out (body
, &n_outputs
, &n_inputs
);
483 if (which_alternative
< 0)
486 /* Avoid further trouble with this insn. */
487 PATTERN (insn
) = gen_rtx_USE (VOIDmode
, const0_rtx
);
490 const operand_alternative
*op_alt
= which_op_alt ();
492 /* Strip SUBREGs here to make the following code simpler. */
493 for (i
= 0; i
< recog_data
.n_operands
; i
++)
494 if (GET_CODE (recog_data
.operand
[i
]) == SUBREG
495 && REG_P (SUBREG_REG (recog_data
.operand
[i
])))
496 recog_data
.operand
[i
] = SUBREG_REG (recog_data
.operand
[i
]);
498 /* Set up CLOBBER_REG. */
502 if (GET_CODE (body
) == PARALLEL
)
504 clobber_reg
= XALLOCAVEC (rtx
, XVECLEN (body
, 0));
506 for (i
= 0; i
< XVECLEN (body
, 0); i
++)
507 if (GET_CODE (XVECEXP (body
, 0, i
)) == CLOBBER
)
509 rtx clobber
= XVECEXP (body
, 0, i
);
510 rtx reg
= XEXP (clobber
, 0);
512 if (GET_CODE (reg
) == SUBREG
&& REG_P (SUBREG_REG (reg
)))
513 reg
= SUBREG_REG (reg
);
515 if (STACK_REG_P (reg
))
517 clobber_reg
[n_clobbers
] = reg
;
523 /* Enforce rule #4: Output operands must specifically indicate which
524 reg an output appears in after an asm. "=f" is not allowed: the
525 operand constraints must select a class with a single reg.
527 Also enforce rule #5: Output operands must start at the top of
528 the reg-stack: output operands may not "skip" a reg. */
530 memset (reg_used_as_output
, 0, sizeof (reg_used_as_output
));
531 for (i
= 0; i
< n_outputs
; i
++)
532 if (STACK_REG_P (recog_data
.operand
[i
]))
534 if (reg_class_size
[(int) op_alt
[i
].cl
] != 1)
536 error_for_asm (insn
, "output constraint %d must specify a single register", i
);
543 for (j
= 0; j
< n_clobbers
; j
++)
544 if (REGNO (recog_data
.operand
[i
]) == REGNO (clobber_reg
[j
]))
546 error_for_asm (insn
, "output constraint %d cannot be specified together with \"%s\" clobber",
547 i
, reg_names
[REGNO (clobber_reg
[j
])]);
552 reg_used_as_output
[REGNO (recog_data
.operand
[i
])] = 1;
557 /* Search for first non-popped reg. */
558 for (i
= FIRST_STACK_REG
; i
< LAST_STACK_REG
+ 1; i
++)
559 if (! reg_used_as_output
[i
])
562 /* If there are any other popped regs, that's an error. */
563 for (; i
< LAST_STACK_REG
+ 1; i
++)
564 if (reg_used_as_output
[i
])
567 if (i
!= LAST_STACK_REG
+ 1)
569 error_for_asm (insn
, "output regs must be grouped at top of stack");
573 /* Enforce rule #2: All implicitly popped input regs must be closer
574 to the top of the reg-stack than any input that is not implicitly
577 memset (implicitly_dies
, 0, sizeof (implicitly_dies
));
578 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
579 if (STACK_REG_P (recog_data
.operand
[i
]))
581 /* An input reg is implicitly popped if it is tied to an
582 output, or if there is a CLOBBER for it. */
585 for (j
= 0; j
< n_clobbers
; j
++)
586 if (operands_match_p (clobber_reg
[j
], recog_data
.operand
[i
]))
589 if (j
< n_clobbers
|| op_alt
[i
].matches
>= 0)
590 implicitly_dies
[REGNO (recog_data
.operand
[i
])] = 1;
593 /* Search for first non-popped reg. */
594 for (i
= FIRST_STACK_REG
; i
< LAST_STACK_REG
+ 1; i
++)
595 if (! implicitly_dies
[i
])
598 /* If there are any other popped regs, that's an error. */
599 for (; i
< LAST_STACK_REG
+ 1; i
++)
600 if (implicitly_dies
[i
])
603 if (i
!= LAST_STACK_REG
+ 1)
606 "implicitly popped regs must be grouped at top of stack");
610 /* Enforce rule #3: If any input operand uses the "f" constraint, all
611 output constraints must use the "&" earlyclobber.
613 ??? Detect this more deterministically by having constrain_asm_operands
614 record any earlyclobber. */
616 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
617 if (op_alt
[i
].matches
== -1)
621 for (j
= 0; j
< n_outputs
; j
++)
622 if (operands_match_p (recog_data
.operand
[j
], recog_data
.operand
[i
]))
625 "output operand %d must use %<&%> constraint", j
);
632 /* Avoid further trouble with this insn. */
633 PATTERN (insn
) = gen_rtx_USE (VOIDmode
, const0_rtx
);
634 any_malformed_asm
= true;
641 /* Calculate the number of inputs and outputs in BODY, an
642 asm_operands. N_OPERANDS is the total number of operands, and
643 N_INPUTS and N_OUTPUTS are pointers to ints into which the results are
647 get_asm_operands_in_out (rtx body
, int *pout
, int *pin
)
649 rtx asmop
= extract_asm_operands (body
);
651 *pin
= ASM_OPERANDS_INPUT_LENGTH (asmop
);
652 *pout
= (recog_data
.n_operands
653 - ASM_OPERANDS_INPUT_LENGTH (asmop
)
654 - ASM_OPERANDS_LABEL_LENGTH (asmop
));
657 /* If current function returns its result in an fp stack register,
658 return the REG. Otherwise, return 0. */
661 stack_result (tree decl
)
665 /* If the value is supposed to be returned in memory, then clearly
666 it is not returned in a stack register. */
667 if (aggregate_value_p (DECL_RESULT (decl
), decl
))
670 result
= DECL_RTL_IF_SET (DECL_RESULT (decl
));
672 result
= targetm
.calls
.function_value (TREE_TYPE (DECL_RESULT (decl
)),
675 return result
!= 0 && STACK_REG_P (result
) ? result
: 0;
680 * This section deals with stack register substitution, and forms the second
684 /* Replace REG, which is a pointer to a stack reg RTX, with an RTX for
685 the desired hard REGNO. */
688 replace_reg (rtx
*reg
, int regno
)
690 gcc_assert (IN_RANGE (regno
, FIRST_STACK_REG
, LAST_STACK_REG
));
691 gcc_assert (STACK_REG_P (*reg
));
693 gcc_assert (SCALAR_FLOAT_MODE_P (GET_MODE (*reg
))
694 || GET_MODE_CLASS (GET_MODE (*reg
)) == MODE_COMPLEX_FLOAT
);
696 *reg
= FP_MODE_REG (regno
, GET_MODE (*reg
));
699 /* Remove a note of type NOTE, which must be found, for register
700 number REGNO from INSN. Remove only one such note. */
703 remove_regno_note (rtx_insn
*insn
, enum reg_note note
, unsigned int regno
)
705 rtx
*note_link
, this_rtx
;
707 note_link
= ®_NOTES (insn
);
708 for (this_rtx
= *note_link
; this_rtx
; this_rtx
= XEXP (this_rtx
, 1))
709 if (REG_NOTE_KIND (this_rtx
) == note
710 && REG_P (XEXP (this_rtx
, 0)) && REGNO (XEXP (this_rtx
, 0)) == regno
)
712 *note_link
= XEXP (this_rtx
, 1);
716 note_link
= &XEXP (this_rtx
, 1);
721 /* Find the hard register number of virtual register REG in REGSTACK.
722 The hard register number is relative to the top of the stack. -1 is
723 returned if the register is not found. */
726 get_hard_regnum (stack_ptr regstack
, rtx reg
)
730 gcc_assert (STACK_REG_P (reg
));
732 for (i
= regstack
->top
; i
>= 0; i
--)
733 if (regstack
->reg
[i
] == REGNO (reg
))
736 return i
>= 0 ? (FIRST_STACK_REG
+ regstack
->top
- i
) : -1;
739 /* Emit an insn to pop virtual register REG before or after INSN.
740 REGSTACK is the stack state after INSN and is updated to reflect this
741 pop. WHEN is either emit_insn_before or emit_insn_after. A pop insn
742 is represented as a SET whose destination is the register to be popped
743 and source is the top of stack. A death note for the top of stack
744 cases the movdf pattern to pop. */
747 emit_pop_insn (rtx_insn
*insn
, stack_ptr regstack
, rtx reg
, enum emit_where where
)
753 /* For complex types take care to pop both halves. These may survive in
754 CLOBBER and USE expressions. */
755 if (COMPLEX_MODE_P (GET_MODE (reg
)))
757 rtx reg1
= FP_MODE_REG (REGNO (reg
), DFmode
);
758 rtx reg2
= FP_MODE_REG (REGNO (reg
) + 1, DFmode
);
761 if (get_hard_regnum (regstack
, reg1
) >= 0)
762 pop_insn
= emit_pop_insn (insn
, regstack
, reg1
, where
);
763 if (get_hard_regnum (regstack
, reg2
) >= 0)
764 pop_insn
= emit_pop_insn (insn
, regstack
, reg2
, where
);
765 gcc_assert (pop_insn
);
769 hard_regno
= get_hard_regnum (regstack
, reg
);
771 gcc_assert (hard_regno
>= FIRST_STACK_REG
);
773 pop_rtx
= gen_rtx_SET (VOIDmode
, FP_MODE_REG (hard_regno
, DFmode
),
774 FP_MODE_REG (FIRST_STACK_REG
, DFmode
));
776 if (where
== EMIT_AFTER
)
777 pop_insn
= emit_insn_after (pop_rtx
, insn
);
779 pop_insn
= emit_insn_before (pop_rtx
, insn
);
781 add_reg_note (pop_insn
, REG_DEAD
, FP_MODE_REG (FIRST_STACK_REG
, DFmode
));
783 regstack
->reg
[regstack
->top
- (hard_regno
- FIRST_STACK_REG
)]
784 = regstack
->reg
[regstack
->top
];
786 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (reg
));
791 /* Emit an insn before or after INSN to swap virtual register REG with
792 the top of stack. REGSTACK is the stack state before the swap, and
793 is updated to reflect the swap. A swap insn is represented as a
794 PARALLEL of two patterns: each pattern moves one reg to the other.
796 If REG is already at the top of the stack, no insn is emitted. */
799 emit_swap_insn (rtx_insn
*insn
, stack_ptr regstack
, rtx reg
)
803 int tmp
, other_reg
; /* swap regno temps */
804 rtx_insn
*i1
; /* the stack-reg insn prior to INSN */
805 rtx i1set
= NULL_RTX
; /* the SET rtx within I1 */
807 hard_regno
= get_hard_regnum (regstack
, reg
);
809 if (hard_regno
== FIRST_STACK_REG
)
811 if (hard_regno
== -1)
813 /* Something failed if the register wasn't on the stack. If we had
814 malformed asms, we zapped the instruction itself, but that didn't
815 produce the same pattern of register sets as before. To prevent
816 further failure, adjust REGSTACK to include REG at TOP. */
817 gcc_assert (any_malformed_asm
);
818 regstack
->reg
[++regstack
->top
] = REGNO (reg
);
821 gcc_assert (hard_regno
>= FIRST_STACK_REG
);
823 other_reg
= regstack
->top
- (hard_regno
- FIRST_STACK_REG
);
825 tmp
= regstack
->reg
[other_reg
];
826 regstack
->reg
[other_reg
] = regstack
->reg
[regstack
->top
];
827 regstack
->reg
[regstack
->top
] = tmp
;
829 /* Find the previous insn involving stack regs, but don't pass a
832 if (current_block
&& insn
!= BB_HEAD (current_block
))
834 rtx_insn
*tmp
= PREV_INSN (insn
);
835 rtx_insn
*limit
= PREV_INSN (BB_HEAD (current_block
));
840 || NOTE_INSN_BASIC_BLOCK_P (tmp
)
841 || (NONJUMP_INSN_P (tmp
)
842 && stack_regs_mentioned (tmp
)))
847 tmp
= PREV_INSN (tmp
);
852 && (i1set
= single_set (i1
)) != NULL_RTX
)
854 rtx i1src
= *get_true_reg (&SET_SRC (i1set
));
855 rtx i1dest
= *get_true_reg (&SET_DEST (i1set
));
857 /* If the previous register stack push was from the reg we are to
858 swap with, omit the swap. */
860 if (REG_P (i1dest
) && REGNO (i1dest
) == FIRST_STACK_REG
862 && REGNO (i1src
) == (unsigned) hard_regno
- 1
863 && find_regno_note (i1
, REG_DEAD
, FIRST_STACK_REG
) == NULL_RTX
)
866 /* If the previous insn wrote to the reg we are to swap with,
869 if (REG_P (i1dest
) && REGNO (i1dest
) == (unsigned) hard_regno
870 && REG_P (i1src
) && REGNO (i1src
) == FIRST_STACK_REG
871 && find_regno_note (i1
, REG_DEAD
, FIRST_STACK_REG
) == NULL_RTX
)
875 /* Avoid emitting the swap if this is the first register stack insn
876 of the current_block. Instead update the current_block's stack_in
877 and let compensate edges take care of this for us. */
878 if (current_block
&& starting_stack_p
)
880 BLOCK_INFO (current_block
)->stack_in
= *regstack
;
881 starting_stack_p
= false;
885 swap_rtx
= gen_swapxf (FP_MODE_REG (hard_regno
, XFmode
),
886 FP_MODE_REG (FIRST_STACK_REG
, XFmode
));
889 emit_insn_after (swap_rtx
, i1
);
890 else if (current_block
)
891 emit_insn_before (swap_rtx
, BB_HEAD (current_block
));
893 emit_insn_before (swap_rtx
, insn
);
896 /* Emit an insns before INSN to swap virtual register SRC1 with
897 the top of stack and virtual register SRC2 with second stack
898 slot. REGSTACK is the stack state before the swaps, and
899 is updated to reflect the swaps. A swap insn is represented as a
900 PARALLEL of two patterns: each pattern moves one reg to the other.
902 If SRC1 and/or SRC2 are already at the right place, no swap insn
906 swap_to_top (rtx_insn
*insn
, stack_ptr regstack
, rtx src1
, rtx src2
)
908 struct stack_def temp_stack
;
909 int regno
, j
, k
, temp
;
911 temp_stack
= *regstack
;
913 /* Place operand 1 at the top of stack. */
914 regno
= get_hard_regnum (&temp_stack
, src1
);
915 gcc_assert (regno
>= 0);
916 if (regno
!= FIRST_STACK_REG
)
918 k
= temp_stack
.top
- (regno
- FIRST_STACK_REG
);
921 temp
= temp_stack
.reg
[k
];
922 temp_stack
.reg
[k
] = temp_stack
.reg
[j
];
923 temp_stack
.reg
[j
] = temp
;
926 /* Place operand 2 next on the stack. */
927 regno
= get_hard_regnum (&temp_stack
, src2
);
928 gcc_assert (regno
>= 0);
929 if (regno
!= FIRST_STACK_REG
+ 1)
931 k
= temp_stack
.top
- (regno
- FIRST_STACK_REG
);
932 j
= temp_stack
.top
- 1;
934 temp
= temp_stack
.reg
[k
];
935 temp_stack
.reg
[k
] = temp_stack
.reg
[j
];
936 temp_stack
.reg
[j
] = temp
;
939 change_stack (insn
, regstack
, &temp_stack
, EMIT_BEFORE
);
942 /* Handle a move to or from a stack register in PAT, which is in INSN.
943 REGSTACK is the current stack. Return whether a control flow insn
944 was deleted in the process. */
947 move_for_stack_reg (rtx_insn
*insn
, stack_ptr regstack
, rtx pat
)
949 rtx
*psrc
= get_true_reg (&SET_SRC (pat
));
950 rtx
*pdest
= get_true_reg (&SET_DEST (pat
));
953 bool control_flow_insn_deleted
= false;
955 src
= *psrc
; dest
= *pdest
;
957 if (STACK_REG_P (src
) && STACK_REG_P (dest
))
959 /* Write from one stack reg to another. If SRC dies here, then
960 just change the register mapping and delete the insn. */
962 note
= find_regno_note (insn
, REG_DEAD
, REGNO (src
));
967 /* If this is a no-op move, there must not be a REG_DEAD note. */
968 gcc_assert (REGNO (src
) != REGNO (dest
));
970 for (i
= regstack
->top
; i
>= 0; i
--)
971 if (regstack
->reg
[i
] == REGNO (src
))
974 /* The destination must be dead, or life analysis is borked. */
975 gcc_assert (get_hard_regnum (regstack
, dest
) < FIRST_STACK_REG
);
977 /* If the source is not live, this is yet another case of
978 uninitialized variables. Load up a NaN instead. */
980 return move_nan_for_stack_reg (insn
, regstack
, dest
);
982 /* It is possible that the dest is unused after this insn.
983 If so, just pop the src. */
985 if (find_regno_note (insn
, REG_UNUSED
, REGNO (dest
)))
986 emit_pop_insn (insn
, regstack
, src
, EMIT_AFTER
);
989 regstack
->reg
[i
] = REGNO (dest
);
990 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (dest
));
991 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (src
));
994 control_flow_insn_deleted
|= control_flow_insn_p (insn
);
996 return control_flow_insn_deleted
;
999 /* The source reg does not die. */
1001 /* If this appears to be a no-op move, delete it, or else it
1002 will confuse the machine description output patterns. But if
1003 it is REG_UNUSED, we must pop the reg now, as per-insn processing
1004 for REG_UNUSED will not work for deleted insns. */
1006 if (REGNO (src
) == REGNO (dest
))
1008 if (find_regno_note (insn
, REG_UNUSED
, REGNO (dest
)))
1009 emit_pop_insn (insn
, regstack
, dest
, EMIT_AFTER
);
1011 control_flow_insn_deleted
|= control_flow_insn_p (insn
);
1013 return control_flow_insn_deleted
;
1016 /* The destination ought to be dead. */
1017 gcc_assert (get_hard_regnum (regstack
, dest
) < FIRST_STACK_REG
);
1019 replace_reg (psrc
, get_hard_regnum (regstack
, src
));
1021 regstack
->reg
[++regstack
->top
] = REGNO (dest
);
1022 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (dest
));
1023 replace_reg (pdest
, FIRST_STACK_REG
);
1025 else if (STACK_REG_P (src
))
1027 /* Save from a stack reg to MEM, or possibly integer reg. Since
1028 only top of stack may be saved, emit an exchange first if
1031 emit_swap_insn (insn
, regstack
, src
);
1033 note
= find_regno_note (insn
, REG_DEAD
, REGNO (src
));
1036 replace_reg (&XEXP (note
, 0), FIRST_STACK_REG
);
1038 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (src
));
1040 else if ((GET_MODE (src
) == XFmode
)
1041 && regstack
->top
< REG_STACK_SIZE
- 1)
1043 /* A 387 cannot write an XFmode value to a MEM without
1044 clobbering the source reg. The output code can handle
1045 this by reading back the value from the MEM.
1046 But it is more efficient to use a temp register if one is
1047 available. Push the source value here if the register
1048 stack is not full, and then write the value to memory via
1051 rtx top_stack_reg
= FP_MODE_REG (FIRST_STACK_REG
, GET_MODE (src
));
1053 push_rtx
= gen_movxf (top_stack_reg
, top_stack_reg
);
1054 emit_insn_before (push_rtx
, insn
);
1055 add_reg_note (insn
, REG_DEAD
, top_stack_reg
);
1058 replace_reg (psrc
, FIRST_STACK_REG
);
1062 rtx pat
= PATTERN (insn
);
1064 gcc_assert (STACK_REG_P (dest
));
1066 /* Load from MEM, or possibly integer REG or constant, into the
1067 stack regs. The actual target is always the top of the
1068 stack. The stack mapping is changed to reflect that DEST is
1069 now at top of stack. */
1071 /* The destination ought to be dead. However, there is a
1072 special case with i387 UNSPEC_TAN, where destination is live
1073 (an argument to fptan) but inherent load of 1.0 is modelled
1074 as a load from a constant. */
1075 if (GET_CODE (pat
) == PARALLEL
1076 && XVECLEN (pat
, 0) == 2
1077 && GET_CODE (XVECEXP (pat
, 0, 1)) == SET
1078 && GET_CODE (SET_SRC (XVECEXP (pat
, 0, 1))) == UNSPEC
1079 && XINT (SET_SRC (XVECEXP (pat
, 0, 1)), 1) == UNSPEC_TAN
)
1080 emit_swap_insn (insn
, regstack
, dest
);
1082 gcc_assert (get_hard_regnum (regstack
, dest
) < FIRST_STACK_REG
);
1084 gcc_assert (regstack
->top
< REG_STACK_SIZE
);
1086 regstack
->reg
[++regstack
->top
] = REGNO (dest
);
1087 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (dest
));
1088 replace_reg (pdest
, FIRST_STACK_REG
);
1091 return control_flow_insn_deleted
;
1094 /* A helper function which replaces INSN with a pattern that loads up
1095 a NaN into DEST, then invokes move_for_stack_reg. */
1098 move_nan_for_stack_reg (rtx_insn
*insn
, stack_ptr regstack
, rtx dest
)
1102 dest
= FP_MODE_REG (REGNO (dest
), SFmode
);
1103 pat
= gen_rtx_SET (VOIDmode
, dest
, not_a_num
);
1104 PATTERN (insn
) = pat
;
1105 INSN_CODE (insn
) = -1;
1107 return move_for_stack_reg (insn
, regstack
, pat
);
1110 /* Swap the condition on a branch, if there is one. Return true if we
1111 found a condition to swap. False if the condition was not used as
1115 swap_rtx_condition_1 (rtx pat
)
1120 if (COMPARISON_P (pat
))
1122 PUT_CODE (pat
, swap_condition (GET_CODE (pat
)));
1127 fmt
= GET_RTX_FORMAT (GET_CODE (pat
));
1128 for (i
= GET_RTX_LENGTH (GET_CODE (pat
)) - 1; i
>= 0; i
--)
1134 for (j
= XVECLEN (pat
, i
) - 1; j
>= 0; j
--)
1135 r
|= swap_rtx_condition_1 (XVECEXP (pat
, i
, j
));
1137 else if (fmt
[i
] == 'e')
1138 r
|= swap_rtx_condition_1 (XEXP (pat
, i
));
1146 swap_rtx_condition (rtx_insn
*insn
)
1148 rtx pat
= PATTERN (insn
);
1150 /* We're looking for a single set to cc0 or an HImode temporary. */
1152 if (GET_CODE (pat
) == SET
1153 && REG_P (SET_DEST (pat
))
1154 && REGNO (SET_DEST (pat
)) == FLAGS_REG
)
1156 insn
= next_flags_user (insn
);
1157 if (insn
== NULL_RTX
)
1159 pat
= PATTERN (insn
);
1162 /* See if this is, or ends in, a fnstsw. If so, we're not doing anything
1163 with the cc value right now. We may be able to search for one
1166 if (GET_CODE (pat
) == SET
1167 && GET_CODE (SET_SRC (pat
)) == UNSPEC
1168 && XINT (SET_SRC (pat
), 1) == UNSPEC_FNSTSW
)
1170 rtx dest
= SET_DEST (pat
);
1172 /* Search forward looking for the first use of this value.
1173 Stop at block boundaries. */
1174 while (insn
!= BB_END (current_block
))
1176 insn
= NEXT_INSN (insn
);
1177 if (INSN_P (insn
) && reg_mentioned_p (dest
, insn
))
1183 /* We haven't found it. */
1184 if (insn
== BB_END (current_block
))
1187 /* So we've found the insn using this value. If it is anything
1188 other than sahf or the value does not die (meaning we'd have
1189 to search further), then we must give up. */
1190 pat
= PATTERN (insn
);
1191 if (GET_CODE (pat
) != SET
1192 || GET_CODE (SET_SRC (pat
)) != UNSPEC
1193 || XINT (SET_SRC (pat
), 1) != UNSPEC_SAHF
1194 || ! dead_or_set_p (insn
, dest
))
1197 /* Now we are prepared to handle this as a normal cc0 setter. */
1198 insn
= next_flags_user (insn
);
1199 if (insn
== NULL_RTX
)
1201 pat
= PATTERN (insn
);
1204 if (swap_rtx_condition_1 (pat
))
1207 INSN_CODE (insn
) = -1;
1208 if (recog_memoized (insn
) == -1)
1210 /* In case the flags don't die here, recurse to try fix
1211 following user too. */
1212 else if (! dead_or_set_p (insn
, ix86_flags_rtx
))
1214 insn
= next_flags_user (insn
);
1215 if (!insn
|| !swap_rtx_condition (insn
))
1220 swap_rtx_condition_1 (pat
);
1228 /* Handle a comparison. Special care needs to be taken to avoid
1229 causing comparisons that a 387 cannot do correctly, such as EQ.
1231 Also, a pop insn may need to be emitted. The 387 does have an
1232 `fcompp' insn that can pop two regs, but it is sometimes too expensive
1233 to do this - a `fcomp' followed by a `fstpl %st(0)' may be easier to
1237 compare_for_stack_reg (rtx_insn
*insn
, stack_ptr regstack
, rtx pat_src
)
1240 rtx src1_note
, src2_note
;
1242 src1
= get_true_reg (&XEXP (pat_src
, 0));
1243 src2
= get_true_reg (&XEXP (pat_src
, 1));
1245 /* ??? If fxch turns out to be cheaper than fstp, give priority to
1246 registers that die in this insn - move those to stack top first. */
1247 if ((! STACK_REG_P (*src1
)
1248 || (STACK_REG_P (*src2
)
1249 && get_hard_regnum (regstack
, *src2
) == FIRST_STACK_REG
))
1250 && swap_rtx_condition (insn
))
1253 temp
= XEXP (pat_src
, 0);
1254 XEXP (pat_src
, 0) = XEXP (pat_src
, 1);
1255 XEXP (pat_src
, 1) = temp
;
1257 src1
= get_true_reg (&XEXP (pat_src
, 0));
1258 src2
= get_true_reg (&XEXP (pat_src
, 1));
1260 INSN_CODE (insn
) = -1;
1263 /* We will fix any death note later. */
1265 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1267 if (STACK_REG_P (*src2
))
1268 src2_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src2
));
1270 src2_note
= NULL_RTX
;
1272 emit_swap_insn (insn
, regstack
, *src1
);
1274 replace_reg (src1
, FIRST_STACK_REG
);
1276 if (STACK_REG_P (*src2
))
1277 replace_reg (src2
, get_hard_regnum (regstack
, *src2
));
1281 pop_stack (regstack
, REGNO (XEXP (src1_note
, 0)));
1282 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1285 /* If the second operand dies, handle that. But if the operands are
1286 the same stack register, don't bother, because only one death is
1287 needed, and it was just handled. */
1290 && ! (STACK_REG_P (*src1
) && STACK_REG_P (*src2
)
1291 && REGNO (*src1
) == REGNO (*src2
)))
1293 /* As a special case, two regs may die in this insn if src2 is
1294 next to top of stack and the top of stack also dies. Since
1295 we have already popped src1, "next to top of stack" is really
1296 at top (FIRST_STACK_REG) now. */
1298 if (get_hard_regnum (regstack
, XEXP (src2_note
, 0)) == FIRST_STACK_REG
1301 pop_stack (regstack
, REGNO (XEXP (src2_note
, 0)));
1302 replace_reg (&XEXP (src2_note
, 0), FIRST_STACK_REG
+ 1);
1306 /* The 386 can only represent death of the first operand in
1307 the case handled above. In all other cases, emit a separate
1308 pop and remove the death note from here. */
1309 remove_regno_note (insn
, REG_DEAD
, REGNO (XEXP (src2_note
, 0)));
1310 emit_pop_insn (insn
, regstack
, XEXP (src2_note
, 0),
1316 /* Substitute hardware stack regs in debug insn INSN, using stack
1317 layout REGSTACK. If we can't find a hardware stack reg for any of
1318 the REGs in it, reset the debug insn. */
1321 subst_all_stack_regs_in_debug_insn (rtx_insn
*insn
, struct stack_def
*regstack
)
1323 subrtx_ptr_iterator::array_type array
;
1324 FOR_EACH_SUBRTX_PTR (iter
, array
, &INSN_VAR_LOCATION_LOC (insn
), NONCONST
)
1328 if (STACK_REG_P (x
))
1330 int hard_regno
= get_hard_regnum (regstack
, x
);
1332 /* If we can't find an active register, reset this debug insn. */
1333 if (hard_regno
== -1)
1335 INSN_VAR_LOCATION_LOC (insn
) = gen_rtx_UNKNOWN_VAR_LOC ();
1339 gcc_assert (hard_regno
>= FIRST_STACK_REG
);
1340 replace_reg (loc
, hard_regno
);
1341 iter
.skip_subrtxes ();
1346 /* Substitute new registers in PAT, which is part of INSN. REGSTACK
1347 is the current register layout. Return whether a control flow insn
1348 was deleted in the process. */
1351 subst_stack_regs_pat (rtx_insn
*insn
, stack_ptr regstack
, rtx pat
)
1354 bool control_flow_insn_deleted
= false;
1356 switch (GET_CODE (pat
))
1359 /* Deaths in USE insns can happen in non optimizing compilation.
1360 Handle them by popping the dying register. */
1361 src
= get_true_reg (&XEXP (pat
, 0));
1362 if (STACK_REG_P (*src
)
1363 && find_regno_note (insn
, REG_DEAD
, REGNO (*src
)))
1365 /* USEs are ignored for liveness information so USEs of dead
1366 register might happen. */
1367 if (TEST_HARD_REG_BIT (regstack
->reg_set
, REGNO (*src
)))
1368 emit_pop_insn (insn
, regstack
, *src
, EMIT_AFTER
);
1369 return control_flow_insn_deleted
;
1371 /* Uninitialized USE might happen for functions returning uninitialized
1372 value. We will properly initialize the USE on the edge to EXIT_BLOCK,
1373 so it is safe to ignore the use here. This is consistent with behavior
1374 of dataflow analyzer that ignores USE too. (This also imply that
1375 forcibly initializing the register to NaN here would lead to ICE later,
1376 since the REG_DEAD notes are not issued.) */
1386 dest
= get_true_reg (&XEXP (pat
, 0));
1387 if (STACK_REG_P (*dest
))
1389 note
= find_reg_note (insn
, REG_DEAD
, *dest
);
1391 if (pat
!= PATTERN (insn
))
1393 /* The fix_truncdi_1 pattern wants to be able to
1394 allocate its own scratch register. It does this by
1395 clobbering an fp reg so that it is assured of an
1396 empty reg-stack register. If the register is live,
1397 kill it now. Remove the DEAD/UNUSED note so we
1398 don't try to kill it later too.
1400 In reality the UNUSED note can be absent in some
1401 complicated cases when the register is reused for
1402 partially set variable. */
1405 emit_pop_insn (insn
, regstack
, *dest
, EMIT_BEFORE
);
1407 note
= find_reg_note (insn
, REG_UNUSED
, *dest
);
1409 remove_note (insn
, note
);
1410 replace_reg (dest
, FIRST_STACK_REG
+ 1);
1414 /* A top-level clobber with no REG_DEAD, and no hard-regnum
1415 indicates an uninitialized value. Because reload removed
1416 all other clobbers, this must be due to a function
1417 returning without a value. Load up a NaN. */
1422 if (COMPLEX_MODE_P (GET_MODE (t
)))
1424 rtx u
= FP_MODE_REG (REGNO (t
) + 1, SFmode
);
1425 if (get_hard_regnum (regstack
, u
) == -1)
1427 rtx pat2
= gen_rtx_CLOBBER (VOIDmode
, u
);
1428 rtx_insn
*insn2
= emit_insn_before (pat2
, insn
);
1429 control_flow_insn_deleted
1430 |= move_nan_for_stack_reg (insn2
, regstack
, u
);
1433 if (get_hard_regnum (regstack
, t
) == -1)
1434 control_flow_insn_deleted
1435 |= move_nan_for_stack_reg (insn
, regstack
, t
);
1444 rtx
*src1
= (rtx
*) 0, *src2
;
1445 rtx src1_note
, src2_note
;
1448 dest
= get_true_reg (&SET_DEST (pat
));
1449 src
= get_true_reg (&SET_SRC (pat
));
1450 pat_src
= SET_SRC (pat
);
1452 /* See if this is a `movM' pattern, and handle elsewhere if so. */
1453 if (STACK_REG_P (*src
)
1454 || (STACK_REG_P (*dest
)
1455 && (REG_P (*src
) || MEM_P (*src
)
1456 || CONST_DOUBLE_P (*src
))))
1458 control_flow_insn_deleted
|= move_for_stack_reg (insn
, regstack
, pat
);
1462 switch (GET_CODE (pat_src
))
1465 compare_for_stack_reg (insn
, regstack
, pat_src
);
1471 for (count
= hard_regno_nregs
[REGNO (*dest
)][GET_MODE (*dest
)];
1474 regstack
->reg
[++regstack
->top
] = REGNO (*dest
) + count
;
1475 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
) + count
);
1478 replace_reg (dest
, FIRST_STACK_REG
);
1482 /* This is a `tstM2' case. */
1483 gcc_assert (*dest
== cc0_rtx
);
1488 case FLOAT_TRUNCATE
:
1492 /* These insns only operate on the top of the stack. DEST might
1493 be cc0_rtx if we're processing a tstM pattern. Also, it's
1494 possible that the tstM case results in a REG_DEAD note on the
1498 src1
= get_true_reg (&XEXP (pat_src
, 0));
1500 emit_swap_insn (insn
, regstack
, *src1
);
1502 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1504 if (STACK_REG_P (*dest
))
1505 replace_reg (dest
, FIRST_STACK_REG
);
1509 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1511 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (*src1
));
1514 replace_reg (src1
, FIRST_STACK_REG
);
1519 /* On i386, reversed forms of subM3 and divM3 exist for
1520 MODE_FLOAT, so the same code that works for addM3 and mulM3
1524 /* These insns can accept the top of stack as a destination
1525 from a stack reg or mem, or can use the top of stack as a
1526 source and some other stack register (possibly top of stack)
1527 as a destination. */
1529 src1
= get_true_reg (&XEXP (pat_src
, 0));
1530 src2
= get_true_reg (&XEXP (pat_src
, 1));
1532 /* We will fix any death note later. */
1534 if (STACK_REG_P (*src1
))
1535 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1537 src1_note
= NULL_RTX
;
1538 if (STACK_REG_P (*src2
))
1539 src2_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src2
));
1541 src2_note
= NULL_RTX
;
1543 /* If either operand is not a stack register, then the dest
1544 must be top of stack. */
1546 if (! STACK_REG_P (*src1
) || ! STACK_REG_P (*src2
))
1547 emit_swap_insn (insn
, regstack
, *dest
);
1550 /* Both operands are REG. If neither operand is already
1551 at the top of stack, choose to make the one that is the
1552 dest the new top of stack. */
1554 int src1_hard_regnum
, src2_hard_regnum
;
1556 src1_hard_regnum
= get_hard_regnum (regstack
, *src1
);
1557 src2_hard_regnum
= get_hard_regnum (regstack
, *src2
);
1559 /* If the source is not live, this is yet another case of
1560 uninitialized variables. Load up a NaN instead. */
1561 if (src1_hard_regnum
== -1)
1563 rtx pat2
= gen_rtx_CLOBBER (VOIDmode
, *src1
);
1564 rtx_insn
*insn2
= emit_insn_before (pat2
, insn
);
1565 control_flow_insn_deleted
1566 |= move_nan_for_stack_reg (insn2
, regstack
, *src1
);
1568 if (src2_hard_regnum
== -1)
1570 rtx pat2
= gen_rtx_CLOBBER (VOIDmode
, *src2
);
1571 rtx_insn
*insn2
= emit_insn_before (pat2
, insn
);
1572 control_flow_insn_deleted
1573 |= move_nan_for_stack_reg (insn2
, regstack
, *src2
);
1576 if (src1_hard_regnum
!= FIRST_STACK_REG
1577 && src2_hard_regnum
!= FIRST_STACK_REG
)
1578 emit_swap_insn (insn
, regstack
, *dest
);
1581 if (STACK_REG_P (*src1
))
1582 replace_reg (src1
, get_hard_regnum (regstack
, *src1
));
1583 if (STACK_REG_P (*src2
))
1584 replace_reg (src2
, get_hard_regnum (regstack
, *src2
));
1588 rtx src1_reg
= XEXP (src1_note
, 0);
1590 /* If the register that dies is at the top of stack, then
1591 the destination is somewhere else - merely substitute it.
1592 But if the reg that dies is not at top of stack, then
1593 move the top of stack to the dead reg, as though we had
1594 done the insn and then a store-with-pop. */
1596 if (REGNO (src1_reg
) == regstack
->reg
[regstack
->top
])
1598 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1599 replace_reg (dest
, get_hard_regnum (regstack
, *dest
));
1603 int regno
= get_hard_regnum (regstack
, src1_reg
);
1605 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1606 replace_reg (dest
, regno
);
1608 regstack
->reg
[regstack
->top
- (regno
- FIRST_STACK_REG
)]
1609 = regstack
->reg
[regstack
->top
];
1612 CLEAR_HARD_REG_BIT (regstack
->reg_set
,
1613 REGNO (XEXP (src1_note
, 0)));
1614 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1619 rtx src2_reg
= XEXP (src2_note
, 0);
1620 if (REGNO (src2_reg
) == regstack
->reg
[regstack
->top
])
1622 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1623 replace_reg (dest
, get_hard_regnum (regstack
, *dest
));
1627 int regno
= get_hard_regnum (regstack
, src2_reg
);
1629 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1630 replace_reg (dest
, regno
);
1632 regstack
->reg
[regstack
->top
- (regno
- FIRST_STACK_REG
)]
1633 = regstack
->reg
[regstack
->top
];
1636 CLEAR_HARD_REG_BIT (regstack
->reg_set
,
1637 REGNO (XEXP (src2_note
, 0)));
1638 replace_reg (&XEXP (src2_note
, 0), FIRST_STACK_REG
);
1643 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1644 replace_reg (dest
, get_hard_regnum (regstack
, *dest
));
1647 /* Keep operand 1 matching with destination. */
1648 if (COMMUTATIVE_ARITH_P (pat_src
)
1649 && REG_P (*src1
) && REG_P (*src2
)
1650 && REGNO (*src1
) != REGNO (*dest
))
1652 int tmp
= REGNO (*src1
);
1653 replace_reg (src1
, REGNO (*src2
));
1654 replace_reg (src2
, tmp
);
1659 switch (XINT (pat_src
, 1))
1664 case UNSPEC_FIST_FLOOR
:
1665 case UNSPEC_FIST_CEIL
:
1667 /* These insns only operate on the top of the stack. */
1669 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1670 emit_swap_insn (insn
, regstack
, *src1
);
1672 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1674 if (STACK_REG_P (*dest
))
1675 replace_reg (dest
, FIRST_STACK_REG
);
1679 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1681 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (*src1
));
1684 replace_reg (src1
, FIRST_STACK_REG
);
1689 /* This insn only operate on the top of the stack. */
1691 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1692 emit_swap_insn (insn
, regstack
, *src1
);
1694 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1696 replace_reg (src1
, FIRST_STACK_REG
);
1700 remove_regno_note (insn
, REG_DEAD
,
1701 REGNO (XEXP (src1_note
, 0)));
1702 emit_pop_insn (insn
, regstack
, XEXP (src1_note
, 0),
1710 case UNSPEC_FRNDINT
:
1713 case UNSPEC_FRNDINT_FLOOR
:
1714 case UNSPEC_FRNDINT_CEIL
:
1715 case UNSPEC_FRNDINT_TRUNC
:
1716 case UNSPEC_FRNDINT_MASK_PM
:
1718 /* Above insns operate on the top of the stack. */
1720 case UNSPEC_SINCOS_COS
:
1721 case UNSPEC_XTRACT_FRACT
:
1723 /* Above insns operate on the top two stack slots,
1724 first part of one input, double output insn. */
1726 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1728 emit_swap_insn (insn
, regstack
, *src1
);
1730 /* Input should never die, it is replaced with output. */
1731 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1732 gcc_assert (!src1_note
);
1734 if (STACK_REG_P (*dest
))
1735 replace_reg (dest
, FIRST_STACK_REG
);
1737 replace_reg (src1
, FIRST_STACK_REG
);
1740 case UNSPEC_SINCOS_SIN
:
1741 case UNSPEC_XTRACT_EXP
:
1743 /* These insns operate on the top two stack slots,
1744 second part of one input, double output insn. */
1751 /* For UNSPEC_TAN, regstack->top is already increased
1752 by inherent load of constant 1.0. */
1754 /* Output value is generated in the second stack slot.
1755 Move current value from second slot to the top. */
1756 regstack
->reg
[regstack
->top
]
1757 = regstack
->reg
[regstack
->top
- 1];
1759 gcc_assert (STACK_REG_P (*dest
));
1761 regstack
->reg
[regstack
->top
- 1] = REGNO (*dest
);
1762 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1763 replace_reg (dest
, FIRST_STACK_REG
+ 1);
1765 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1767 replace_reg (src1
, FIRST_STACK_REG
);
1772 case UNSPEC_FYL2XP1
:
1773 /* These insns operate on the top two stack slots. */
1775 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1776 src2
= get_true_reg (&XVECEXP (pat_src
, 0, 1));
1778 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1779 src2_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src2
));
1781 swap_to_top (insn
, regstack
, *src1
, *src2
);
1783 replace_reg (src1
, FIRST_STACK_REG
);
1784 replace_reg (src2
, FIRST_STACK_REG
+ 1);
1787 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1789 replace_reg (&XEXP (src2_note
, 0), FIRST_STACK_REG
+ 1);
1791 /* Pop both input operands from the stack. */
1792 CLEAR_HARD_REG_BIT (regstack
->reg_set
,
1793 regstack
->reg
[regstack
->top
]);
1794 CLEAR_HARD_REG_BIT (regstack
->reg_set
,
1795 regstack
->reg
[regstack
->top
- 1]);
1798 /* Push the result back onto the stack. */
1799 regstack
->reg
[++regstack
->top
] = REGNO (*dest
);
1800 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1801 replace_reg (dest
, FIRST_STACK_REG
);
1804 case UNSPEC_FSCALE_FRACT
:
1805 case UNSPEC_FPREM_F
:
1806 case UNSPEC_FPREM1_F
:
1807 /* These insns operate on the top two stack slots,
1808 first part of double input, double output insn. */
1810 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1811 src2
= get_true_reg (&XVECEXP (pat_src
, 0, 1));
1813 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1814 src2_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src2
));
1816 /* Inputs should never die, they are
1817 replaced with outputs. */
1818 gcc_assert (!src1_note
);
1819 gcc_assert (!src2_note
);
1821 swap_to_top (insn
, regstack
, *src1
, *src2
);
1823 /* Push the result back onto stack. Empty stack slot
1824 will be filled in second part of insn. */
1825 if (STACK_REG_P (*dest
))
1827 regstack
->reg
[regstack
->top
] = REGNO (*dest
);
1828 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1829 replace_reg (dest
, FIRST_STACK_REG
);
1832 replace_reg (src1
, FIRST_STACK_REG
);
1833 replace_reg (src2
, FIRST_STACK_REG
+ 1);
1836 case UNSPEC_FSCALE_EXP
:
1837 case UNSPEC_FPREM_U
:
1838 case UNSPEC_FPREM1_U
:
1839 /* These insns operate on the top two stack slots,
1840 second part of double input, double output insn. */
1842 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1843 src2
= get_true_reg (&XVECEXP (pat_src
, 0, 1));
1845 /* Push the result back onto stack. Fill empty slot from
1846 first part of insn and fix top of stack pointer. */
1847 if (STACK_REG_P (*dest
))
1849 regstack
->reg
[regstack
->top
- 1] = REGNO (*dest
);
1850 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1851 replace_reg (dest
, FIRST_STACK_REG
+ 1);
1854 replace_reg (src1
, FIRST_STACK_REG
);
1855 replace_reg (src2
, FIRST_STACK_REG
+ 1);
1858 case UNSPEC_C2_FLAG
:
1859 /* This insn operates on the top two stack slots,
1860 third part of C2 setting double input insn. */
1862 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1863 src2
= get_true_reg (&XVECEXP (pat_src
, 0, 1));
1865 replace_reg (src1
, FIRST_STACK_REG
);
1866 replace_reg (src2
, FIRST_STACK_REG
+ 1);
1870 /* (unspec [(unspec [(compare)] UNSPEC_FNSTSW)] UNSPEC_SAHF)
1871 The combination matches the PPRO fcomi instruction. */
1873 pat_src
= XVECEXP (pat_src
, 0, 0);
1874 gcc_assert (GET_CODE (pat_src
) == UNSPEC
);
1875 gcc_assert (XINT (pat_src
, 1) == UNSPEC_FNSTSW
);
1879 /* Combined fcomp+fnstsw generated for doing well with
1880 CSE. When optimizing this would have been broken
1883 pat_src
= XVECEXP (pat_src
, 0, 0);
1884 gcc_assert (GET_CODE (pat_src
) == COMPARE
);
1886 compare_for_stack_reg (insn
, regstack
, pat_src
);
1895 /* This insn requires the top of stack to be the destination. */
1897 src1
= get_true_reg (&XEXP (pat_src
, 1));
1898 src2
= get_true_reg (&XEXP (pat_src
, 2));
1900 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1901 src2_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src2
));
1903 /* If the comparison operator is an FP comparison operator,
1904 it is handled correctly by compare_for_stack_reg () who
1905 will move the destination to the top of stack. But if the
1906 comparison operator is not an FP comparison operator, we
1907 have to handle it here. */
1908 if (get_hard_regnum (regstack
, *dest
) >= FIRST_STACK_REG
1909 && REGNO (*dest
) != regstack
->reg
[regstack
->top
])
1911 /* In case one of operands is the top of stack and the operands
1912 dies, it is safe to make it the destination operand by
1913 reversing the direction of cmove and avoid fxch. */
1914 if ((REGNO (*src1
) == regstack
->reg
[regstack
->top
]
1916 || (REGNO (*src2
) == regstack
->reg
[regstack
->top
]
1919 int idx1
= (get_hard_regnum (regstack
, *src1
)
1921 int idx2
= (get_hard_regnum (regstack
, *src2
)
1924 /* Make reg-stack believe that the operands are already
1925 swapped on the stack */
1926 regstack
->reg
[regstack
->top
- idx1
] = REGNO (*src2
);
1927 regstack
->reg
[regstack
->top
- idx2
] = REGNO (*src1
);
1929 /* Reverse condition to compensate the operand swap.
1930 i386 do have comparison always reversible. */
1931 PUT_CODE (XEXP (pat_src
, 0),
1932 reversed_comparison_code (XEXP (pat_src
, 0), insn
));
1935 emit_swap_insn (insn
, regstack
, *dest
);
1943 src_note
[1] = src1_note
;
1944 src_note
[2] = src2_note
;
1946 if (STACK_REG_P (*src1
))
1947 replace_reg (src1
, get_hard_regnum (regstack
, *src1
));
1948 if (STACK_REG_P (*src2
))
1949 replace_reg (src2
, get_hard_regnum (regstack
, *src2
));
1951 for (i
= 1; i
<= 2; i
++)
1954 int regno
= REGNO (XEXP (src_note
[i
], 0));
1956 /* If the register that dies is not at the top of
1957 stack, then move the top of stack to the dead reg.
1958 Top of stack should never die, as it is the
1960 gcc_assert (regno
!= regstack
->reg
[regstack
->top
]);
1961 remove_regno_note (insn
, REG_DEAD
, regno
);
1962 emit_pop_insn (insn
, regstack
, XEXP (src_note
[i
], 0),
1967 /* Make dest the top of stack. Add dest to regstack if
1969 if (get_hard_regnum (regstack
, *dest
) < FIRST_STACK_REG
)
1970 regstack
->reg
[++regstack
->top
] = REGNO (*dest
);
1971 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1972 replace_reg (dest
, FIRST_STACK_REG
);
1985 return control_flow_insn_deleted
;
1988 /* Substitute hard regnums for any stack regs in INSN, which has
1989 N_INPUTS inputs and N_OUTPUTS outputs. REGSTACK is the stack info
1990 before the insn, and is updated with changes made here.
1992 There are several requirements and assumptions about the use of
1993 stack-like regs in asm statements. These rules are enforced by
1994 record_asm_stack_regs; see comments there for details. Any
1995 asm_operands left in the RTL at this point may be assume to meet the
1996 requirements, since record_asm_stack_regs removes any problem asm. */
1999 subst_asm_stack_regs (rtx_insn
*insn
, stack_ptr regstack
)
2001 rtx body
= PATTERN (insn
);
2003 rtx
*note_reg
; /* Array of note contents */
2004 rtx
**note_loc
; /* Address of REG field of each note */
2005 enum reg_note
*note_kind
; /* The type of each note */
2007 rtx
*clobber_reg
= 0;
2008 rtx
**clobber_loc
= 0;
2010 struct stack_def temp_stack
;
2015 int n_inputs
, n_outputs
;
2017 if (! check_asm_stack_operands (insn
))
2020 /* Find out what the constraints required. If no constraint
2021 alternative matches, that is a compiler bug: we should have caught
2022 such an insn in check_asm_stack_operands. */
2023 extract_constrain_insn (insn
);
2025 preprocess_constraints (insn
);
2026 const operand_alternative
*op_alt
= which_op_alt ();
2028 get_asm_operands_in_out (body
, &n_outputs
, &n_inputs
);
2030 /* Strip SUBREGs here to make the following code simpler. */
2031 for (i
= 0; i
< recog_data
.n_operands
; i
++)
2032 if (GET_CODE (recog_data
.operand
[i
]) == SUBREG
2033 && REG_P (SUBREG_REG (recog_data
.operand
[i
])))
2035 recog_data
.operand_loc
[i
] = & SUBREG_REG (recog_data
.operand
[i
]);
2036 recog_data
.operand
[i
] = SUBREG_REG (recog_data
.operand
[i
]);
2039 /* Set up NOTE_REG, NOTE_LOC and NOTE_KIND. */
2041 for (i
= 0, note
= REG_NOTES (insn
); note
; note
= XEXP (note
, 1))
2044 note_reg
= XALLOCAVEC (rtx
, i
);
2045 note_loc
= XALLOCAVEC (rtx
*, i
);
2046 note_kind
= XALLOCAVEC (enum reg_note
, i
);
2049 for (note
= REG_NOTES (insn
); note
; note
= XEXP (note
, 1))
2051 if (GET_CODE (note
) != EXPR_LIST
)
2053 rtx reg
= XEXP (note
, 0);
2054 rtx
*loc
= & XEXP (note
, 0);
2056 if (GET_CODE (reg
) == SUBREG
&& REG_P (SUBREG_REG (reg
)))
2058 loc
= & SUBREG_REG (reg
);
2059 reg
= SUBREG_REG (reg
);
2062 if (STACK_REG_P (reg
)
2063 && (REG_NOTE_KIND (note
) == REG_DEAD
2064 || REG_NOTE_KIND (note
) == REG_UNUSED
))
2066 note_reg
[n_notes
] = reg
;
2067 note_loc
[n_notes
] = loc
;
2068 note_kind
[n_notes
] = REG_NOTE_KIND (note
);
2073 /* Set up CLOBBER_REG and CLOBBER_LOC. */
2077 if (GET_CODE (body
) == PARALLEL
)
2079 clobber_reg
= XALLOCAVEC (rtx
, XVECLEN (body
, 0));
2080 clobber_loc
= XALLOCAVEC (rtx
*, XVECLEN (body
, 0));
2082 for (i
= 0; i
< XVECLEN (body
, 0); i
++)
2083 if (GET_CODE (XVECEXP (body
, 0, i
)) == CLOBBER
)
2085 rtx clobber
= XVECEXP (body
, 0, i
);
2086 rtx reg
= XEXP (clobber
, 0);
2087 rtx
*loc
= & XEXP (clobber
, 0);
2089 if (GET_CODE (reg
) == SUBREG
&& REG_P (SUBREG_REG (reg
)))
2091 loc
= & SUBREG_REG (reg
);
2092 reg
= SUBREG_REG (reg
);
2095 if (STACK_REG_P (reg
))
2097 clobber_reg
[n_clobbers
] = reg
;
2098 clobber_loc
[n_clobbers
] = loc
;
2104 temp_stack
= *regstack
;
2106 /* Put the input regs into the desired place in TEMP_STACK. */
2108 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
2109 if (STACK_REG_P (recog_data
.operand
[i
])
2110 && reg_class_subset_p (op_alt
[i
].cl
, FLOAT_REGS
)
2111 && op_alt
[i
].cl
!= FLOAT_REGS
)
2113 /* If an operand needs to be in a particular reg in
2114 FLOAT_REGS, the constraint was either 't' or 'u'. Since
2115 these constraints are for single register classes, and
2116 reload guaranteed that operand[i] is already in that class,
2117 we can just use REGNO (recog_data.operand[i]) to know which
2118 actual reg this operand needs to be in. */
2120 int regno
= get_hard_regnum (&temp_stack
, recog_data
.operand
[i
]);
2122 gcc_assert (regno
>= 0);
2124 if ((unsigned int) regno
!= REGNO (recog_data
.operand
[i
]))
2126 /* recog_data.operand[i] is not in the right place. Find
2127 it and swap it with whatever is already in I's place.
2128 K is where recog_data.operand[i] is now. J is where it
2132 k
= temp_stack
.top
- (regno
- FIRST_STACK_REG
);
2134 - (REGNO (recog_data
.operand
[i
]) - FIRST_STACK_REG
));
2136 temp
= temp_stack
.reg
[k
];
2137 temp_stack
.reg
[k
] = temp_stack
.reg
[j
];
2138 temp_stack
.reg
[j
] = temp
;
2142 /* Emit insns before INSN to make sure the reg-stack is in the right
2145 change_stack (insn
, regstack
, &temp_stack
, EMIT_BEFORE
);
2147 /* Make the needed input register substitutions. Do death notes and
2148 clobbers too, because these are for inputs, not outputs. */
2150 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
2151 if (STACK_REG_P (recog_data
.operand
[i
]))
2153 int regnum
= get_hard_regnum (regstack
, recog_data
.operand
[i
]);
2155 gcc_assert (regnum
>= 0);
2157 replace_reg (recog_data
.operand_loc
[i
], regnum
);
2160 for (i
= 0; i
< n_notes
; i
++)
2161 if (note_kind
[i
] == REG_DEAD
)
2163 int regnum
= get_hard_regnum (regstack
, note_reg
[i
]);
2165 gcc_assert (regnum
>= 0);
2167 replace_reg (note_loc
[i
], regnum
);
2170 for (i
= 0; i
< n_clobbers
; i
++)
2172 /* It's OK for a CLOBBER to reference a reg that is not live.
2173 Don't try to replace it in that case. */
2174 int regnum
= get_hard_regnum (regstack
, clobber_reg
[i
]);
2178 /* Sigh - clobbers always have QImode. But replace_reg knows
2179 that these regs can't be MODE_INT and will assert. Just put
2180 the right reg there without calling replace_reg. */
2182 *clobber_loc
[i
] = FP_MODE_REG (regnum
, DFmode
);
2186 /* Now remove from REGSTACK any inputs that the asm implicitly popped. */
2188 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
2189 if (STACK_REG_P (recog_data
.operand
[i
]))
2191 /* An input reg is implicitly popped if it is tied to an
2192 output, or if there is a CLOBBER for it. */
2195 for (j
= 0; j
< n_clobbers
; j
++)
2196 if (operands_match_p (clobber_reg
[j
], recog_data
.operand
[i
]))
2199 if (j
< n_clobbers
|| op_alt
[i
].matches
>= 0)
2201 /* recog_data.operand[i] might not be at the top of stack.
2202 But that's OK, because all we need to do is pop the
2203 right number of regs off of the top of the reg-stack.
2204 record_asm_stack_regs guaranteed that all implicitly
2205 popped regs were grouped at the top of the reg-stack. */
2207 CLEAR_HARD_REG_BIT (regstack
->reg_set
,
2208 regstack
->reg
[regstack
->top
]);
2213 /* Now add to REGSTACK any outputs that the asm implicitly pushed.
2214 Note that there isn't any need to substitute register numbers.
2215 ??? Explain why this is true. */
2217 for (i
= LAST_STACK_REG
; i
>= FIRST_STACK_REG
; i
--)
2219 /* See if there is an output for this hard reg. */
2222 for (j
= 0; j
< n_outputs
; j
++)
2223 if (STACK_REG_P (recog_data
.operand
[j
])
2224 && REGNO (recog_data
.operand
[j
]) == (unsigned) i
)
2226 regstack
->reg
[++regstack
->top
] = i
;
2227 SET_HARD_REG_BIT (regstack
->reg_set
, i
);
2232 /* Now emit a pop insn for any REG_UNUSED output, or any REG_DEAD
2233 input that the asm didn't implicitly pop. If the asm didn't
2234 implicitly pop an input reg, that reg will still be live.
2236 Note that we can't use find_regno_note here: the register numbers
2237 in the death notes have already been substituted. */
2239 for (i
= 0; i
< n_outputs
; i
++)
2240 if (STACK_REG_P (recog_data
.operand
[i
]))
2244 for (j
= 0; j
< n_notes
; j
++)
2245 if (REGNO (recog_data
.operand
[i
]) == REGNO (note_reg
[j
])
2246 && note_kind
[j
] == REG_UNUSED
)
2248 insn
= emit_pop_insn (insn
, regstack
, recog_data
.operand
[i
],
2254 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
2255 if (STACK_REG_P (recog_data
.operand
[i
]))
2259 for (j
= 0; j
< n_notes
; j
++)
2260 if (REGNO (recog_data
.operand
[i
]) == REGNO (note_reg
[j
])
2261 && note_kind
[j
] == REG_DEAD
2262 && TEST_HARD_REG_BIT (regstack
->reg_set
,
2263 REGNO (recog_data
.operand
[i
])))
2265 insn
= emit_pop_insn (insn
, regstack
, recog_data
.operand
[i
],
2272 /* Substitute stack hard reg numbers for stack virtual registers in
2273 INSN. Non-stack register numbers are not changed. REGSTACK is the
2274 current stack content. Insns may be emitted as needed to arrange the
2275 stack for the 387 based on the contents of the insn. Return whether
2276 a control flow insn was deleted in the process. */
2279 subst_stack_regs (rtx_insn
*insn
, stack_ptr regstack
)
2281 rtx
*note_link
, note
;
2282 bool control_flow_insn_deleted
= false;
2287 int top
= regstack
->top
;
2289 /* If there are any floating point parameters to be passed in
2290 registers for this call, make sure they are in the right
2295 straighten_stack (insn
, regstack
);
2297 /* Now mark the arguments as dead after the call. */
2299 while (regstack
->top
>= 0)
2301 CLEAR_HARD_REG_BIT (regstack
->reg_set
, FIRST_STACK_REG
+ regstack
->top
);
2307 /* Do the actual substitution if any stack regs are mentioned.
2308 Since we only record whether entire insn mentions stack regs, and
2309 subst_stack_regs_pat only works for patterns that contain stack regs,
2310 we must check each pattern in a parallel here. A call_value_pop could
2313 if (stack_regs_mentioned (insn
))
2315 int n_operands
= asm_noperands (PATTERN (insn
));
2316 if (n_operands
>= 0)
2318 /* This insn is an `asm' with operands. Decode the operands,
2319 decide how many are inputs, and do register substitution.
2320 Any REG_UNUSED notes will be handled by subst_asm_stack_regs. */
2322 subst_asm_stack_regs (insn
, regstack
);
2323 return control_flow_insn_deleted
;
2326 if (GET_CODE (PATTERN (insn
)) == PARALLEL
)
2327 for (i
= 0; i
< XVECLEN (PATTERN (insn
), 0); i
++)
2329 if (stack_regs_mentioned_p (XVECEXP (PATTERN (insn
), 0, i
)))
2331 if (GET_CODE (XVECEXP (PATTERN (insn
), 0, i
)) == CLOBBER
)
2332 XVECEXP (PATTERN (insn
), 0, i
)
2333 = shallow_copy_rtx (XVECEXP (PATTERN (insn
), 0, i
));
2334 control_flow_insn_deleted
2335 |= subst_stack_regs_pat (insn
, regstack
,
2336 XVECEXP (PATTERN (insn
), 0, i
));
2340 control_flow_insn_deleted
2341 |= subst_stack_regs_pat (insn
, regstack
, PATTERN (insn
));
2344 /* subst_stack_regs_pat may have deleted a no-op insn. If so, any
2345 REG_UNUSED will already have been dealt with, so just return. */
2347 if (NOTE_P (insn
) || insn
->deleted ())
2348 return control_flow_insn_deleted
;
2350 /* If this a noreturn call, we can't insert pop insns after it.
2351 Instead, reset the stack state to empty. */
2353 && find_reg_note (insn
, REG_NORETURN
, NULL
))
2356 CLEAR_HARD_REG_SET (regstack
->reg_set
);
2357 return control_flow_insn_deleted
;
2360 /* If there is a REG_UNUSED note on a stack register on this insn,
2361 the indicated reg must be popped. The REG_UNUSED note is removed,
2362 since the form of the newly emitted pop insn references the reg,
2363 making it no longer `unset'. */
2365 note_link
= ®_NOTES (insn
);
2366 for (note
= *note_link
; note
; note
= XEXP (note
, 1))
2367 if (REG_NOTE_KIND (note
) == REG_UNUSED
&& STACK_REG_P (XEXP (note
, 0)))
2369 *note_link
= XEXP (note
, 1);
2370 insn
= emit_pop_insn (insn
, regstack
, XEXP (note
, 0), EMIT_AFTER
);
2373 note_link
= &XEXP (note
, 1);
2375 return control_flow_insn_deleted
;
2378 /* Change the organization of the stack so that it fits a new basic
2379 block. Some registers might have to be popped, but there can never be
2380 a register live in the new block that is not now live.
2382 Insert any needed insns before or after INSN, as indicated by
2383 WHERE. OLD is the original stack layout, and NEW is the desired
2384 form. OLD is updated to reflect the code emitted, i.e., it will be
2385 the same as NEW upon return.
2387 This function will not preserve block_end[]. But that information
2388 is no longer needed once this has executed. */
2391 change_stack (rtx_insn
*insn
, stack_ptr old
, stack_ptr new_stack
,
2392 enum emit_where where
)
2398 /* Stack adjustments for the first insn in a block update the
2399 current_block's stack_in instead of inserting insns directly.
2400 compensate_edges will add the necessary code later. */
2403 && where
== EMIT_BEFORE
)
2405 BLOCK_INFO (current_block
)->stack_in
= *new_stack
;
2406 starting_stack_p
= false;
2411 /* We will be inserting new insns "backwards". If we are to insert
2412 after INSN, find the next insn, and insert before it. */
2414 if (where
== EMIT_AFTER
)
2416 if (current_block
&& BB_END (current_block
) == insn
)
2418 insn
= NEXT_INSN (insn
);
2421 /* Initialize partially dead variables. */
2422 for (i
= FIRST_STACK_REG
; i
< LAST_STACK_REG
+ 1; i
++)
2423 if (TEST_HARD_REG_BIT (new_stack
->reg_set
, i
)
2424 && !TEST_HARD_REG_BIT (old
->reg_set
, i
))
2426 old
->reg
[++old
->top
] = i
;
2427 SET_HARD_REG_BIT (old
->reg_set
, i
);
2428 emit_insn_before (gen_rtx_SET (VOIDmode
,
2429 FP_MODE_REG (i
, SFmode
), not_a_num
), insn
);
2432 /* Pop any registers that are not needed in the new block. */
2434 /* If the destination block's stack already has a specified layout
2435 and contains two or more registers, use a more intelligent algorithm
2436 to pop registers that minimizes the number number of fxchs below. */
2437 if (new_stack
->top
> 0)
2439 bool slots
[REG_STACK_SIZE
];
2440 int pops
[REG_STACK_SIZE
];
2441 int next
, dest
, topsrc
;
2443 /* First pass to determine the free slots. */
2444 for (reg
= 0; reg
<= new_stack
->top
; reg
++)
2445 slots
[reg
] = TEST_HARD_REG_BIT (new_stack
->reg_set
, old
->reg
[reg
]);
2447 /* Second pass to allocate preferred slots. */
2449 for (reg
= old
->top
; reg
> new_stack
->top
; reg
--)
2450 if (TEST_HARD_REG_BIT (new_stack
->reg_set
, old
->reg
[reg
]))
2453 for (next
= 0; next
<= new_stack
->top
; next
++)
2454 if (!slots
[next
] && new_stack
->reg
[next
] == old
->reg
[reg
])
2456 /* If this is a preference for the new top of stack, record
2457 the fact by remembering it's old->reg in topsrc. */
2458 if (next
== new_stack
->top
)
2469 /* Intentionally, avoid placing the top of stack in it's correct
2470 location, if we still need to permute the stack below and we
2471 can usefully place it somewhere else. This is the case if any
2472 slot is still unallocated, in which case we should place the
2473 top of stack there. */
2475 for (reg
= 0; reg
< new_stack
->top
; reg
++)
2479 slots
[new_stack
->top
] = false;
2484 /* Third pass allocates remaining slots and emits pop insns. */
2485 next
= new_stack
->top
;
2486 for (reg
= old
->top
; reg
> new_stack
->top
; reg
--)
2491 /* Find next free slot. */
2496 emit_pop_insn (insn
, old
, FP_MODE_REG (old
->reg
[dest
], DFmode
),
2502 /* The following loop attempts to maximize the number of times we
2503 pop the top of the stack, as this permits the use of the faster
2504 ffreep instruction on platforms that support it. */
2508 for (reg
= 0; reg
<= old
->top
; reg
++)
2509 if (TEST_HARD_REG_BIT (new_stack
->reg_set
, old
->reg
[reg
]))
2513 while (old
->top
>= live
)
2514 if (TEST_HARD_REG_BIT (new_stack
->reg_set
, old
->reg
[old
->top
]))
2516 while (TEST_HARD_REG_BIT (new_stack
->reg_set
, old
->reg
[next
]))
2518 emit_pop_insn (insn
, old
, FP_MODE_REG (old
->reg
[next
], DFmode
),
2522 emit_pop_insn (insn
, old
, FP_MODE_REG (old
->reg
[old
->top
], DFmode
),
2526 if (new_stack
->top
== -2)
2528 /* If the new block has never been processed, then it can inherit
2529 the old stack order. */
2531 new_stack
->top
= old
->top
;
2532 memcpy (new_stack
->reg
, old
->reg
, sizeof (new_stack
->reg
));
2536 /* This block has been entered before, and we must match the
2537 previously selected stack order. */
2539 /* By now, the only difference should be the order of the stack,
2540 not their depth or liveliness. */
2542 gcc_assert (hard_reg_set_equal_p (old
->reg_set
, new_stack
->reg_set
));
2543 gcc_assert (old
->top
== new_stack
->top
);
2545 /* If the stack is not empty (new_stack->top != -1), loop here emitting
2546 swaps until the stack is correct.
2548 The worst case number of swaps emitted is N + 2, where N is the
2549 depth of the stack. In some cases, the reg at the top of
2550 stack may be correct, but swapped anyway in order to fix
2551 other regs. But since we never swap any other reg away from
2552 its correct slot, this algorithm will converge. */
2554 if (new_stack
->top
!= -1)
2557 /* Swap the reg at top of stack into the position it is
2558 supposed to be in, until the correct top of stack appears. */
2560 while (old
->reg
[old
->top
] != new_stack
->reg
[new_stack
->top
])
2562 for (reg
= new_stack
->top
; reg
>= 0; reg
--)
2563 if (new_stack
->reg
[reg
] == old
->reg
[old
->top
])
2566 gcc_assert (reg
!= -1);
2568 emit_swap_insn (insn
, old
,
2569 FP_MODE_REG (old
->reg
[reg
], DFmode
));
2572 /* See if any regs remain incorrect. If so, bring an
2573 incorrect reg to the top of stack, and let the while loop
2576 for (reg
= new_stack
->top
; reg
>= 0; reg
--)
2577 if (new_stack
->reg
[reg
] != old
->reg
[reg
])
2579 emit_swap_insn (insn
, old
,
2580 FP_MODE_REG (old
->reg
[reg
], DFmode
));
2585 /* At this point there must be no differences. */
2587 for (reg
= old
->top
; reg
>= 0; reg
--)
2588 gcc_assert (old
->reg
[reg
] == new_stack
->reg
[reg
]);
2592 BB_END (current_block
) = PREV_INSN (insn
);
2595 /* Print stack configuration. */
2598 print_stack (FILE *file
, stack_ptr s
)
2604 fprintf (file
, "uninitialized\n");
2605 else if (s
->top
== -1)
2606 fprintf (file
, "empty\n");
2611 for (i
= 0; i
<= s
->top
; ++i
)
2612 fprintf (file
, "%d ", s
->reg
[i
]);
2613 fputs ("]\n", file
);
2617 /* This function was doing life analysis. We now let the regular live
2618 code do it's job, so we only need to check some extra invariants
2619 that reg-stack expects. Primary among these being that all registers
2620 are initialized before use.
2622 The function returns true when code was emitted to CFG edges and
2623 commit_edge_insertions needs to be called. */
2626 convert_regs_entry (void)
2632 /* Load something into each stack register live at function entry.
2633 Such live registers can be caused by uninitialized variables or
2634 functions not returning values on all paths. In order to keep
2635 the push/pop code happy, and to not scrog the register stack, we
2636 must put something in these registers. Use a QNaN.
2638 Note that we are inserting converted code here. This code is
2639 never seen by the convert_regs pass. */
2641 FOR_EACH_EDGE (e
, ei
, ENTRY_BLOCK_PTR_FOR_FN (cfun
)->succs
)
2643 basic_block block
= e
->dest
;
2644 block_info bi
= BLOCK_INFO (block
);
2647 for (reg
= LAST_STACK_REG
; reg
>= FIRST_STACK_REG
; --reg
)
2648 if (TEST_HARD_REG_BIT (bi
->stack_in
.reg_set
, reg
))
2652 bi
->stack_in
.reg
[++top
] = reg
;
2654 init
= gen_rtx_SET (VOIDmode
,
2655 FP_MODE_REG (FIRST_STACK_REG
, SFmode
),
2657 insert_insn_on_edge (init
, e
);
2661 bi
->stack_in
.top
= top
;
2667 /* Construct the desired stack for function exit. This will either
2668 be `empty', or the function return value at top-of-stack. */
2671 convert_regs_exit (void)
2673 int value_reg_low
, value_reg_high
;
2674 stack_ptr output_stack
;
2677 retvalue
= stack_result (current_function_decl
);
2678 value_reg_low
= value_reg_high
= -1;
2681 value_reg_low
= REGNO (retvalue
);
2682 value_reg_high
= END_HARD_REGNO (retvalue
) - 1;
2685 output_stack
= &BLOCK_INFO (EXIT_BLOCK_PTR_FOR_FN (cfun
))->stack_in
;
2686 if (value_reg_low
== -1)
2687 output_stack
->top
= -1;
2692 output_stack
->top
= value_reg_high
- value_reg_low
;
2693 for (reg
= value_reg_low
; reg
<= value_reg_high
; ++reg
)
2695 output_stack
->reg
[value_reg_high
- reg
] = reg
;
2696 SET_HARD_REG_BIT (output_stack
->reg_set
, reg
);
2701 /* Copy the stack info from the end of edge E's source block to the
2702 start of E's destination block. */
2705 propagate_stack (edge e
)
2707 stack_ptr src_stack
= &BLOCK_INFO (e
->src
)->stack_out
;
2708 stack_ptr dest_stack
= &BLOCK_INFO (e
->dest
)->stack_in
;
2711 /* Preserve the order of the original stack, but check whether
2712 any pops are needed. */
2713 dest_stack
->top
= -1;
2714 for (reg
= 0; reg
<= src_stack
->top
; ++reg
)
2715 if (TEST_HARD_REG_BIT (dest_stack
->reg_set
, src_stack
->reg
[reg
]))
2716 dest_stack
->reg
[++dest_stack
->top
] = src_stack
->reg
[reg
];
2718 /* Push in any partially dead values. */
2719 for (reg
= FIRST_STACK_REG
; reg
< LAST_STACK_REG
+ 1; reg
++)
2720 if (TEST_HARD_REG_BIT (dest_stack
->reg_set
, reg
)
2721 && !TEST_HARD_REG_BIT (src_stack
->reg_set
, reg
))
2722 dest_stack
->reg
[++dest_stack
->top
] = reg
;
2726 /* Adjust the stack of edge E's source block on exit to match the stack
2727 of it's target block upon input. The stack layouts of both blocks
2728 should have been defined by now. */
2731 compensate_edge (edge e
)
2733 basic_block source
= e
->src
, target
= e
->dest
;
2734 stack_ptr target_stack
= &BLOCK_INFO (target
)->stack_in
;
2735 stack_ptr source_stack
= &BLOCK_INFO (source
)->stack_out
;
2736 struct stack_def regstack
;
2740 fprintf (dump_file
, "Edge %d->%d: ", source
->index
, target
->index
);
2742 gcc_assert (target_stack
->top
!= -2);
2744 /* Check whether stacks are identical. */
2745 if (target_stack
->top
== source_stack
->top
)
2747 for (reg
= target_stack
->top
; reg
>= 0; --reg
)
2748 if (target_stack
->reg
[reg
] != source_stack
->reg
[reg
])
2754 fprintf (dump_file
, "no changes needed\n");
2761 fprintf (dump_file
, "correcting stack to ");
2762 print_stack (dump_file
, target_stack
);
2765 /* Abnormal calls may appear to have values live in st(0), but the
2766 abnormal return path will not have actually loaded the values. */
2767 if (e
->flags
& EDGE_ABNORMAL_CALL
)
2769 /* Assert that the lifetimes are as we expect -- one value
2770 live at st(0) on the end of the source block, and no
2771 values live at the beginning of the destination block.
2772 For complex return values, we may have st(1) live as well. */
2773 gcc_assert (source_stack
->top
== 0 || source_stack
->top
== 1);
2774 gcc_assert (target_stack
->top
== -1);
2778 /* Handle non-call EH edges specially. The normal return path have
2779 values in registers. These will be popped en masse by the unwind
2781 if (e
->flags
& EDGE_EH
)
2783 gcc_assert (target_stack
->top
== -1);
2787 /* We don't support abnormal edges. Global takes care to
2788 avoid any live register across them, so we should never
2789 have to insert instructions on such edges. */
2790 gcc_assert (! (e
->flags
& EDGE_ABNORMAL
));
2792 /* Make a copy of source_stack as change_stack is destructive. */
2793 regstack
= *source_stack
;
2795 /* It is better to output directly to the end of the block
2796 instead of to the edge, because emit_swap can do minimal
2797 insn scheduling. We can do this when there is only one
2798 edge out, and it is not abnormal. */
2799 if (EDGE_COUNT (source
->succs
) == 1)
2801 current_block
= source
;
2802 change_stack (BB_END (source
), ®stack
, target_stack
,
2803 (JUMP_P (BB_END (source
)) ? EMIT_BEFORE
: EMIT_AFTER
));
2810 current_block
= NULL
;
2813 /* ??? change_stack needs some point to emit insns after. */
2814 after
= emit_note (NOTE_INSN_DELETED
);
2816 change_stack (after
, ®stack
, target_stack
, EMIT_BEFORE
);
2821 insert_insn_on_edge (seq
, e
);
2827 /* Traverse all non-entry edges in the CFG, and emit the necessary
2828 edge compensation code to change the stack from stack_out of the
2829 source block to the stack_in of the destination block. */
2832 compensate_edges (void)
2834 bool inserted
= false;
2837 starting_stack_p
= false;
2839 FOR_EACH_BB_FN (bb
, cfun
)
2840 if (bb
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
))
2845 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2846 inserted
|= compensate_edge (e
);
2851 /* Select the better of two edges E1 and E2 to use to determine the
2852 stack layout for their shared destination basic block. This is
2853 typically the more frequently executed. The edge E1 may be NULL
2854 (in which case E2 is returned), but E2 is always non-NULL. */
2857 better_edge (edge e1
, edge e2
)
2862 if (EDGE_FREQUENCY (e1
) > EDGE_FREQUENCY (e2
))
2864 if (EDGE_FREQUENCY (e1
) < EDGE_FREQUENCY (e2
))
2867 if (e1
->count
> e2
->count
)
2869 if (e1
->count
< e2
->count
)
2872 /* Prefer critical edges to minimize inserting compensation code on
2875 if (EDGE_CRITICAL_P (e1
) != EDGE_CRITICAL_P (e2
))
2876 return EDGE_CRITICAL_P (e1
) ? e1
: e2
;
2878 /* Avoid non-deterministic behavior. */
2879 return (e1
->src
->index
< e2
->src
->index
) ? e1
: e2
;
2882 /* Convert stack register references in one block. Return true if the CFG
2883 has been modified in the process. */
2886 convert_regs_1 (basic_block block
)
2888 struct stack_def regstack
;
2889 block_info bi
= BLOCK_INFO (block
);
2891 rtx_insn
*insn
, *next
;
2892 bool control_flow_insn_deleted
= false;
2893 bool cfg_altered
= false;
2894 int debug_insns_with_starting_stack
= 0;
2896 any_malformed_asm
= false;
2898 /* Choose an initial stack layout, if one hasn't already been chosen. */
2899 if (bi
->stack_in
.top
== -2)
2901 edge e
, beste
= NULL
;
2904 /* Select the best incoming edge (typically the most frequent) to
2905 use as a template for this basic block. */
2906 FOR_EACH_EDGE (e
, ei
, block
->preds
)
2907 if (BLOCK_INFO (e
->src
)->done
)
2908 beste
= better_edge (beste
, e
);
2911 propagate_stack (beste
);
2914 /* No predecessors. Create an arbitrary input stack. */
2915 bi
->stack_in
.top
= -1;
2916 for (reg
= LAST_STACK_REG
; reg
>= FIRST_STACK_REG
; --reg
)
2917 if (TEST_HARD_REG_BIT (bi
->stack_in
.reg_set
, reg
))
2918 bi
->stack_in
.reg
[++bi
->stack_in
.top
] = reg
;
2924 fprintf (dump_file
, "\nBasic block %d\nInput stack: ", block
->index
);
2925 print_stack (dump_file
, &bi
->stack_in
);
2928 /* Process all insns in this block. Keep track of NEXT so that we
2929 don't process insns emitted while substituting in INSN. */
2930 current_block
= block
;
2931 next
= BB_HEAD (block
);
2932 regstack
= bi
->stack_in
;
2933 starting_stack_p
= true;
2938 next
= NEXT_INSN (insn
);
2940 /* Ensure we have not missed a block boundary. */
2942 if (insn
== BB_END (block
))
2945 /* Don't bother processing unless there is a stack reg
2946 mentioned or if it's a CALL_INSN. */
2947 if (DEBUG_INSN_P (insn
))
2949 if (starting_stack_p
)
2950 debug_insns_with_starting_stack
++;
2953 subst_all_stack_regs_in_debug_insn (insn
, ®stack
);
2955 /* Nothing must ever die at a debug insn. If something
2956 is referenced in it that becomes dead, it should have
2957 died before and the reference in the debug insn
2958 should have been removed so as to avoid changing code
2960 gcc_assert (!find_reg_note (insn
, REG_DEAD
, NULL
));
2963 else if (stack_regs_mentioned (insn
)
2968 fprintf (dump_file
, " insn %d input stack: ",
2970 print_stack (dump_file
, ®stack
);
2972 control_flow_insn_deleted
|= subst_stack_regs (insn
, ®stack
);
2973 starting_stack_p
= false;
2978 if (debug_insns_with_starting_stack
)
2980 /* Since it's the first non-debug instruction that determines
2981 the stack requirements of the current basic block, we refrain
2982 from updating debug insns before it in the loop above, and
2983 fix them up here. */
2984 for (insn
= BB_HEAD (block
); debug_insns_with_starting_stack
;
2985 insn
= NEXT_INSN (insn
))
2987 if (!DEBUG_INSN_P (insn
))
2990 debug_insns_with_starting_stack
--;
2991 subst_all_stack_regs_in_debug_insn (insn
, &bi
->stack_in
);
2997 fprintf (dump_file
, "Expected live registers [");
2998 for (reg
= FIRST_STACK_REG
; reg
<= LAST_STACK_REG
; ++reg
)
2999 if (TEST_HARD_REG_BIT (bi
->out_reg_set
, reg
))
3000 fprintf (dump_file
, " %d", reg
);
3001 fprintf (dump_file
, " ]\nOutput stack: ");
3002 print_stack (dump_file
, ®stack
);
3005 insn
= BB_END (block
);
3007 insn
= PREV_INSN (insn
);
3009 /* If the function is declared to return a value, but it returns one
3010 in only some cases, some registers might come live here. Emit
3011 necessary moves for them. */
3013 for (reg
= FIRST_STACK_REG
; reg
<= LAST_STACK_REG
; ++reg
)
3015 if (TEST_HARD_REG_BIT (bi
->out_reg_set
, reg
)
3016 && ! TEST_HARD_REG_BIT (regstack
.reg_set
, reg
))
3021 fprintf (dump_file
, "Emitting insn initializing reg %d\n", reg
);
3023 set
= gen_rtx_SET (VOIDmode
, FP_MODE_REG (reg
, SFmode
), not_a_num
);
3024 insn
= emit_insn_after (set
, insn
);
3025 control_flow_insn_deleted
|= subst_stack_regs (insn
, ®stack
);
3029 /* Amongst the insns possibly deleted during the substitution process above,
3030 might have been the only trapping insn in the block. We purge the now
3031 possibly dead EH edges here to avoid an ICE from fixup_abnormal_edges,
3032 called at the end of convert_regs. The order in which we process the
3033 blocks ensures that we never delete an already processed edge.
3035 Note that, at this point, the CFG may have been damaged by the emission
3036 of instructions after an abnormal call, which moves the basic block end
3037 (and is the reason why we call fixup_abnormal_edges later). So we must
3038 be sure that the trapping insn has been deleted before trying to purge
3039 dead edges, otherwise we risk purging valid edges.
3041 ??? We are normally supposed not to delete trapping insns, so we pretend
3042 that the insns deleted above don't actually trap. It would have been
3043 better to detect this earlier and avoid creating the EH edge in the first
3044 place, still, but we don't have enough information at that time. */
3046 if (control_flow_insn_deleted
)
3047 cfg_altered
|= purge_dead_edges (block
);
3049 /* Something failed if the stack lives don't match. If we had malformed
3050 asms, we zapped the instruction itself, but that didn't produce the
3051 same pattern of register kills as before. */
3053 gcc_assert (hard_reg_set_equal_p (regstack
.reg_set
, bi
->out_reg_set
)
3054 || any_malformed_asm
);
3055 bi
->stack_out
= regstack
;
3061 /* Convert registers in all blocks reachable from BLOCK. Return true if the
3062 CFG has been modified in the process. */
3065 convert_regs_2 (basic_block block
)
3067 basic_block
*stack
, *sp
;
3068 bool cfg_altered
= false;
3070 /* We process the blocks in a top-down manner, in a way such that one block
3071 is only processed after all its predecessors. The number of predecessors
3072 of every block has already been computed. */
3074 stack
= XNEWVEC (basic_block
, n_basic_blocks_for_fn (cfun
));
3086 /* Processing BLOCK is achieved by convert_regs_1, which may purge
3087 some dead EH outgoing edge after the deletion of the trapping
3088 insn inside the block. Since the number of predecessors of
3089 BLOCK's successors was computed based on the initial edge set,
3090 we check the necessity to process some of these successors
3091 before such an edge deletion may happen. However, there is
3092 a pitfall: if BLOCK is the only predecessor of a successor and
3093 the edge between them happens to be deleted, the successor
3094 becomes unreachable and should not be processed. The problem
3095 is that there is no way to preventively detect this case so we
3096 stack the successor in all cases and hand over the task of
3097 fixing up the discrepancy to convert_regs_1. */
3099 FOR_EACH_EDGE (e
, ei
, block
->succs
)
3100 if (! (e
->flags
& EDGE_DFS_BACK
))
3102 BLOCK_INFO (e
->dest
)->predecessors
--;
3103 if (!BLOCK_INFO (e
->dest
)->predecessors
)
3107 cfg_altered
|= convert_regs_1 (block
);
3109 while (sp
!= stack
);
3116 /* Traverse all basic blocks in a function, converting the register
3117 references in each insn from the "flat" register file that gcc uses,
3118 to the stack-like registers the 387 uses. */
3123 bool cfg_altered
= false;
3129 /* Initialize uninitialized registers on function entry. */
3130 inserted
= convert_regs_entry ();
3132 /* Construct the desired stack for function exit. */
3133 convert_regs_exit ();
3134 BLOCK_INFO (EXIT_BLOCK_PTR_FOR_FN (cfun
))->done
= 1;
3136 /* ??? Future: process inner loops first, and give them arbitrary
3137 initial stacks which emit_swap_insn can modify. This ought to
3138 prevent double fxch that often appears at the head of a loop. */
3140 /* Process all blocks reachable from all entry points. */
3141 FOR_EACH_EDGE (e
, ei
, ENTRY_BLOCK_PTR_FOR_FN (cfun
)->succs
)
3142 cfg_altered
|= convert_regs_2 (e
->dest
);
3144 /* ??? Process all unreachable blocks. Though there's no excuse
3145 for keeping these even when not optimizing. */
3146 FOR_EACH_BB_FN (b
, cfun
)
3148 block_info bi
= BLOCK_INFO (b
);
3151 cfg_altered
|= convert_regs_2 (b
);
3154 /* We must fix up abnormal edges before inserting compensation code
3155 because both mechanisms insert insns on edges. */
3156 inserted
|= fixup_abnormal_edges ();
3158 inserted
|= compensate_edges ();
3160 clear_aux_for_blocks ();
3163 commit_edge_insertions ();
3169 fputc ('\n', dump_file
);
3172 /* Convert register usage from "flat" register file usage to a "stack
3173 register file. FILE is the dump file, if used.
3175 Construct a CFG and run life analysis. Then convert each insn one
3176 by one. Run a last cleanup_cfg pass, if optimizing, to eliminate
3177 code duplication created when the converter inserts pop insns on
3187 /* Clean up previous run. */
3188 stack_regs_mentioned_data
.release ();
3190 /* See if there is something to do. Flow analysis is quite
3191 expensive so we might save some compilation time. */
3192 for (i
= FIRST_STACK_REG
; i
<= LAST_STACK_REG
; i
++)
3193 if (df_regs_ever_live_p (i
))
3195 if (i
> LAST_STACK_REG
)
3198 df_note_add_problem ();
3201 mark_dfs_back_edges ();
3203 /* Set up block info for each basic block. */
3204 alloc_aux_for_blocks (sizeof (struct block_info_def
));
3205 FOR_EACH_BB_FN (bb
, cfun
)
3207 block_info bi
= BLOCK_INFO (bb
);
3212 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3213 if (!(e
->flags
& EDGE_DFS_BACK
)
3214 && e
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
))
3217 /* Set current register status at last instruction `uninitialized'. */
3218 bi
->stack_in
.top
= -2;
3220 /* Copy live_at_end and live_at_start into temporaries. */
3221 for (reg
= FIRST_STACK_REG
; reg
<= LAST_STACK_REG
; reg
++)
3223 if (REGNO_REG_SET_P (DF_LR_OUT (bb
), reg
))
3224 SET_HARD_REG_BIT (bi
->out_reg_set
, reg
);
3225 if (REGNO_REG_SET_P (DF_LR_IN (bb
), reg
))
3226 SET_HARD_REG_BIT (bi
->stack_in
.reg_set
, reg
);
3230 /* Create the replacement registers up front. */
3231 for (i
= FIRST_STACK_REG
; i
<= LAST_STACK_REG
; i
++)
3233 enum machine_mode mode
;
3234 for (mode
= GET_CLASS_NARROWEST_MODE (MODE_FLOAT
);
3236 mode
= GET_MODE_WIDER_MODE (mode
))
3237 FP_MODE_REG (i
, mode
) = gen_rtx_REG (mode
, i
);
3238 for (mode
= GET_CLASS_NARROWEST_MODE (MODE_COMPLEX_FLOAT
);
3240 mode
= GET_MODE_WIDER_MODE (mode
))
3241 FP_MODE_REG (i
, mode
) = gen_rtx_REG (mode
, i
);
3244 ix86_flags_rtx
= gen_rtx_REG (CCmode
, FLAGS_REG
);
3246 /* A QNaN for initializing uninitialized variables.
3248 ??? We can't load from constant memory in PIC mode, because
3249 we're inserting these instructions before the prologue and
3250 the PIC register hasn't been set up. In that case, fall back
3251 on zero, which we can get from `fldz'. */
3253 if ((flag_pic
&& !TARGET_64BIT
)
3254 || ix86_cmodel
== CM_LARGE
|| ix86_cmodel
== CM_LARGE_PIC
)
3255 not_a_num
= CONST0_RTX (SFmode
);
3260 real_nan (&r
, "", 1, SFmode
);
3261 not_a_num
= CONST_DOUBLE_FROM_REAL_VALUE (r
, SFmode
);
3262 not_a_num
= force_const_mem (SFmode
, not_a_num
);
3265 /* Allocate a cache for stack_regs_mentioned. */
3266 max_uid
= get_max_uid ();
3267 stack_regs_mentioned_data
.create (max_uid
+ 1);
3268 memset (stack_regs_mentioned_data
.address (),
3269 0, sizeof (char) * (max_uid
+ 1));
3273 free_aux_for_blocks ();
3276 #endif /* STACK_REGS */
3280 const pass_data pass_data_stack_regs
=
3282 RTL_PASS
, /* type */
3283 "*stack_regs", /* name */
3284 OPTGROUP_NONE
, /* optinfo_flags */
3285 TV_REG_STACK
, /* tv_id */
3286 0, /* properties_required */
3287 0, /* properties_provided */
3288 0, /* properties_destroyed */
3289 0, /* todo_flags_start */
3290 0, /* todo_flags_finish */
3293 class pass_stack_regs
: public rtl_opt_pass
3296 pass_stack_regs (gcc::context
*ctxt
)
3297 : rtl_opt_pass (pass_data_stack_regs
, ctxt
)
3300 /* opt_pass methods: */
3301 virtual bool gate (function
*)
3310 }; // class pass_stack_regs
3315 make_pass_stack_regs (gcc::context
*ctxt
)
3317 return new pass_stack_regs (ctxt
);
3320 /* Convert register usage from flat register file usage to a stack
3323 rest_of_handle_stack_regs (void)
3327 regstack_completed
= 1;
3334 const pass_data pass_data_stack_regs_run
=
3336 RTL_PASS
, /* type */
3338 OPTGROUP_NONE
, /* optinfo_flags */
3339 TV_REG_STACK
, /* tv_id */
3340 0, /* properties_required */
3341 0, /* properties_provided */
3342 0, /* properties_destroyed */
3343 0, /* todo_flags_start */
3344 TODO_df_finish
, /* todo_flags_finish */
3347 class pass_stack_regs_run
: public rtl_opt_pass
3350 pass_stack_regs_run (gcc::context
*ctxt
)
3351 : rtl_opt_pass (pass_data_stack_regs_run
, ctxt
)
3354 /* opt_pass methods: */
3355 virtual unsigned int execute (function
*)
3357 return rest_of_handle_stack_regs ();
3360 }; // class pass_stack_regs_run
3365 make_pass_stack_regs_run (gcc::context
*ctxt
)
3367 return new pass_stack_regs_run (ctxt
);