1 /* Register to Stack convert for GNU compiler.
2 Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
3 2001, 2002, 2003, 2004, 2005, 2006, 2007
4 Free Software Foundation, Inc.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it
9 under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
13 GCC is distributed in the hope that it will be useful, but WITHOUT
14 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
15 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
16 License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* This pass converts stack-like registers from the "flat register
23 file" model that gcc uses, to a stack convention that the 387 uses.
25 * The form of the input:
27 On input, the function consists of insn that have had their
28 registers fully allocated to a set of "virtual" registers. Note that
29 the word "virtual" is used differently here than elsewhere in gcc: for
30 each virtual stack reg, there is a hard reg, but the mapping between
31 them is not known until this pass is run. On output, hard register
32 numbers have been substituted, and various pop and exchange insns have
33 been emitted. The hard register numbers and the virtual register
34 numbers completely overlap - before this pass, all stack register
35 numbers are virtual, and afterward they are all hard.
37 The virtual registers can be manipulated normally by gcc, and their
38 semantics are the same as for normal registers. After the hard
39 register numbers are substituted, the semantics of an insn containing
40 stack-like regs are not the same as for an insn with normal regs: for
41 instance, it is not safe to delete an insn that appears to be a no-op
42 move. In general, no insn containing hard regs should be changed
43 after this pass is done.
45 * The form of the output:
47 After this pass, hard register numbers represent the distance from
48 the current top of stack to the desired register. A reference to
49 FIRST_STACK_REG references the top of stack, FIRST_STACK_REG + 1,
50 represents the register just below that, and so forth. Also, REG_DEAD
51 notes indicate whether or not a stack register should be popped.
53 A "swap" insn looks like a parallel of two patterns, where each
54 pattern is a SET: one sets A to B, the other B to A.
56 A "push" or "load" insn is a SET whose SET_DEST is FIRST_STACK_REG
57 and whose SET_DEST is REG or MEM. Any other SET_DEST, such as PLUS,
58 will replace the existing stack top, not push a new value.
60 A store insn is a SET whose SET_DEST is FIRST_STACK_REG, and whose
61 SET_SRC is REG or MEM.
63 The case where the SET_SRC and SET_DEST are both FIRST_STACK_REG
64 appears ambiguous. As a special case, the presence of a REG_DEAD note
65 for FIRST_STACK_REG differentiates between a load insn and a pop.
67 If a REG_DEAD is present, the insn represents a "pop" that discards
68 the top of the register stack. If there is no REG_DEAD note, then the
69 insn represents a "dup" or a push of the current top of stack onto the
74 Existing REG_DEAD and REG_UNUSED notes for stack registers are
75 deleted and recreated from scratch. REG_DEAD is never created for a
76 SET_DEST, only REG_UNUSED.
80 There are several rules on the usage of stack-like regs in
81 asm_operands insns. These rules apply only to the operands that are
84 1. Given a set of input regs that die in an asm_operands, it is
85 necessary to know which are implicitly popped by the asm, and
86 which must be explicitly popped by gcc.
88 An input reg that is implicitly popped by the asm must be
89 explicitly clobbered, unless it is constrained to match an
92 2. For any input reg that is implicitly popped by an asm, it is
93 necessary to know how to adjust the stack to compensate for the pop.
94 If any non-popped input is closer to the top of the reg-stack than
95 the implicitly popped reg, it would not be possible to know what the
96 stack looked like - it's not clear how the rest of the stack "slides
99 All implicitly popped input regs must be closer to the top of
100 the reg-stack than any input that is not implicitly popped.
102 3. It is possible that if an input dies in an insn, reload might
103 use the input reg for an output reload. Consider this example:
105 asm ("foo" : "=t" (a) : "f" (b));
107 This asm says that input B is not popped by the asm, and that
108 the asm pushes a result onto the reg-stack, i.e., the stack is one
109 deeper after the asm than it was before. But, it is possible that
110 reload will think that it can use the same reg for both the input and
111 the output, if input B dies in this insn.
113 If any input operand uses the "f" constraint, all output reg
114 constraints must use the "&" earlyclobber.
116 The asm above would be written as
118 asm ("foo" : "=&t" (a) : "f" (b));
120 4. Some operands need to be in particular places on the stack. All
121 output operands fall in this category - there is no other way to
122 know which regs the outputs appear in unless the user indicates
123 this in the constraints.
125 Output operands must specifically indicate which reg an output
126 appears in after an asm. "=f" is not allowed: the operand
127 constraints must select a class with a single reg.
129 5. Output operands may not be "inserted" between existing stack regs.
130 Since no 387 opcode uses a read/write operand, all output operands
131 are dead before the asm_operands, and are pushed by the asm_operands.
132 It makes no sense to push anywhere but the top of the reg-stack.
134 Output operands must start at the top of the reg-stack: output
135 operands may not "skip" a reg.
137 6. Some asm statements may need extra stack space for internal
138 calculations. This can be guaranteed by clobbering stack registers
139 unrelated to the inputs and outputs.
141 Here are a couple of reasonable asms to want to write. This asm
142 takes one input, which is internally popped, and produces two outputs.
144 asm ("fsincos" : "=t" (cos), "=u" (sin) : "0" (inp));
146 This asm takes two inputs, which are popped by the fyl2xp1 opcode,
147 and replaces them with one output. The user must code the "st(1)"
148 clobber for reg-stack.c to know that fyl2xp1 pops both inputs.
150 asm ("fyl2xp1" : "=t" (result) : "0" (x), "u" (y) : "st(1)");
156 #include "coretypes.h"
161 #include "function.h"
162 #include "insn-config.h"
164 #include "hard-reg-set.h"
169 #include "basic-block.h"
170 #include "cfglayout.h"
175 #include "tree-pass.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,heap
) *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
, int);
254 static rtx
*get_true_reg (rtx
*);
256 static int check_asm_stack_operands (rtx
);
257 static int get_asm_operand_n_inputs (rtx
);
258 static rtx
stack_result (tree
);
259 static void replace_reg (rtx
*, int);
260 static void remove_regno_note (rtx
, enum reg_note
, unsigned int);
261 static int get_hard_regnum (stack
, rtx
);
262 static rtx
emit_pop_insn (rtx
, stack
, rtx
, enum emit_where
);
263 static void swap_to_top(rtx
, stack
, rtx
, rtx
);
264 static bool move_for_stack_reg (rtx
, stack
, rtx
);
265 static bool move_nan_for_stack_reg (rtx
, stack
, rtx
);
266 static int swap_rtx_condition_1 (rtx
);
267 static int swap_rtx_condition (rtx
);
268 static void compare_for_stack_reg (rtx
, stack
, rtx
);
269 static bool subst_stack_regs_pat (rtx
, stack
, rtx
);
270 static void subst_asm_stack_regs (rtx
, stack
);
271 static bool subst_stack_regs (rtx
, stack
);
272 static void change_stack (rtx
, stack
, stack
, enum emit_where
);
273 static void print_stack (FILE *, stack
);
274 static rtx
next_flags_user (rtx
);
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
)
316 uid
= INSN_UID (insn
);
317 max
= VEC_length (char, stack_regs_mentioned_data
);
320 /* Allocate some extra size to avoid too many reallocs, but
321 do not grow too quickly. */
322 max
= uid
+ uid
/ 20 + 1;
323 VEC_safe_grow_cleared (char, heap
, stack_regs_mentioned_data
, max
);
326 test
= VEC_index (char, 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 VEC_replace (char, stack_regs_mentioned_data
, uid
, test
);
337 static rtx ix86_flags_rtx
;
340 next_flags_user (rtx 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
, stack 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 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 (FP_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 pat
= & XVECEXP (*pat
, 0, 0);
443 if (!flag_unsafe_math_optimizations
)
445 pat
= & XEXP (*pat
, 0);
453 /* Set if we find any malformed asms in a block. */
454 static bool any_malformed_asm
;
456 /* There are many rules that an asm statement for stack-like regs must
457 follow. Those rules are explained at the top of this file: the rule
458 numbers below refer to that explanation. */
461 check_asm_stack_operands (rtx insn
)
465 int malformed_asm
= 0;
466 rtx body
= PATTERN (insn
);
468 char reg_used_as_output
[FIRST_PSEUDO_REGISTER
];
469 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. */
478 constrain_operands (1);
479 alt
= which_alternative
;
481 preprocess_constraints ();
483 n_inputs
= get_asm_operand_n_inputs (body
);
484 n_outputs
= recog_data
.n_operands
- n_inputs
;
489 /* Avoid further trouble with this insn. */
490 PATTERN (insn
) = gen_rtx_USE (VOIDmode
, const0_rtx
);
494 /* Strip SUBREGs here to make the following code simpler. */
495 for (i
= 0; i
< recog_data
.n_operands
; i
++)
496 if (GET_CODE (recog_data
.operand
[i
]) == SUBREG
497 && REG_P (SUBREG_REG (recog_data
.operand
[i
])))
498 recog_data
.operand
[i
] = SUBREG_REG (recog_data
.operand
[i
]);
500 /* Set up CLOBBER_REG. */
504 if (GET_CODE (body
) == PARALLEL
)
506 clobber_reg
= XALLOCAVEC (rtx
, XVECLEN (body
, 0));
508 for (i
= 0; i
< XVECLEN (body
, 0); i
++)
509 if (GET_CODE (XVECEXP (body
, 0, i
)) == CLOBBER
)
511 rtx clobber
= XVECEXP (body
, 0, i
);
512 rtx reg
= XEXP (clobber
, 0);
514 if (GET_CODE (reg
) == SUBREG
&& REG_P (SUBREG_REG (reg
)))
515 reg
= SUBREG_REG (reg
);
517 if (STACK_REG_P (reg
))
519 clobber_reg
[n_clobbers
] = reg
;
525 /* Enforce rule #4: Output operands must specifically indicate which
526 reg an output appears in after an asm. "=f" is not allowed: the
527 operand constraints must select a class with a single reg.
529 Also enforce rule #5: Output operands must start at the top of
530 the reg-stack: output operands may not "skip" a reg. */
532 memset (reg_used_as_output
, 0, sizeof (reg_used_as_output
));
533 for (i
= 0; i
< n_outputs
; i
++)
534 if (STACK_REG_P (recog_data
.operand
[i
]))
536 if (reg_class_size
[(int) recog_op_alt
[i
][alt
].cl
] != 1)
538 error_for_asm (insn
, "output constraint %d must specify a single register", i
);
545 for (j
= 0; j
< n_clobbers
; j
++)
546 if (REGNO (recog_data
.operand
[i
]) == REGNO (clobber_reg
[j
]))
548 error_for_asm (insn
, "output constraint %d cannot be specified together with \"%s\" clobber",
549 i
, reg_names
[REGNO (clobber_reg
[j
])]);
554 reg_used_as_output
[REGNO (recog_data
.operand
[i
])] = 1;
559 /* Search for first non-popped reg. */
560 for (i
= FIRST_STACK_REG
; i
< LAST_STACK_REG
+ 1; i
++)
561 if (! reg_used_as_output
[i
])
564 /* If there are any other popped regs, that's an error. */
565 for (; i
< LAST_STACK_REG
+ 1; i
++)
566 if (reg_used_as_output
[i
])
569 if (i
!= LAST_STACK_REG
+ 1)
571 error_for_asm (insn
, "output regs must be grouped at top of stack");
575 /* Enforce rule #2: All implicitly popped input regs must be closer
576 to the top of the reg-stack than any input that is not implicitly
579 memset (implicitly_dies
, 0, sizeof (implicitly_dies
));
580 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
581 if (STACK_REG_P (recog_data
.operand
[i
]))
583 /* An input reg is implicitly popped if it is tied to an
584 output, or if there is a CLOBBER for it. */
587 for (j
= 0; j
< n_clobbers
; j
++)
588 if (operands_match_p (clobber_reg
[j
], recog_data
.operand
[i
]))
591 if (j
< n_clobbers
|| recog_op_alt
[i
][alt
].matches
>= 0)
592 implicitly_dies
[REGNO (recog_data
.operand
[i
])] = 1;
595 /* Search for first non-popped reg. */
596 for (i
= FIRST_STACK_REG
; i
< LAST_STACK_REG
+ 1; i
++)
597 if (! implicitly_dies
[i
])
600 /* If there are any other popped regs, that's an error. */
601 for (; i
< LAST_STACK_REG
+ 1; i
++)
602 if (implicitly_dies
[i
])
605 if (i
!= LAST_STACK_REG
+ 1)
608 "implicitly popped regs must be grouped at top of stack");
612 /* Enforce rule #3: If any input operand uses the "f" constraint, all
613 output constraints must use the "&" earlyclobber.
615 ??? Detect this more deterministically by having constrain_asm_operands
616 record any earlyclobber. */
618 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
619 if (recog_op_alt
[i
][alt
].matches
== -1)
623 for (j
= 0; j
< n_outputs
; j
++)
624 if (operands_match_p (recog_data
.operand
[j
], recog_data
.operand
[i
]))
627 "output operand %d must use %<&%> constraint", j
);
634 /* Avoid further trouble with this insn. */
635 PATTERN (insn
) = gen_rtx_USE (VOIDmode
, const0_rtx
);
636 any_malformed_asm
= true;
643 /* Calculate the number of inputs and outputs in BODY, an
644 asm_operands. N_OPERANDS is the total number of operands, and
645 N_INPUTS and N_OUTPUTS are pointers to ints into which the results are
649 get_asm_operand_n_inputs (rtx body
)
651 switch (GET_CODE (body
))
654 gcc_assert (GET_CODE (SET_SRC (body
)) == ASM_OPERANDS
);
655 return ASM_OPERANDS_INPUT_LENGTH (SET_SRC (body
));
658 return ASM_OPERANDS_INPUT_LENGTH (body
);
661 return get_asm_operand_n_inputs (XVECEXP (body
, 0, 0));
668 /* If current function returns its result in an fp stack register,
669 return the REG. Otherwise, return 0. */
672 stack_result (tree decl
)
676 /* If the value is supposed to be returned in memory, then clearly
677 it is not returned in a stack register. */
678 if (aggregate_value_p (DECL_RESULT (decl
), decl
))
681 result
= DECL_RTL_IF_SET (DECL_RESULT (decl
));
683 result
= targetm
.calls
.function_value (TREE_TYPE (DECL_RESULT (decl
)),
686 return result
!= 0 && STACK_REG_P (result
) ? result
: 0;
691 * This section deals with stack register substitution, and forms the second
695 /* Replace REG, which is a pointer to a stack reg RTX, with an RTX for
696 the desired hard REGNO. */
699 replace_reg (rtx
*reg
, int regno
)
701 gcc_assert (IN_RANGE (regno
, FIRST_STACK_REG
, LAST_STACK_REG
));
702 gcc_assert (STACK_REG_P (*reg
));
704 gcc_assert (SCALAR_FLOAT_MODE_P (GET_MODE (*reg
))
705 || GET_MODE_CLASS (GET_MODE (*reg
)) == MODE_COMPLEX_FLOAT
);
707 *reg
= FP_MODE_REG (regno
, GET_MODE (*reg
));
710 /* Remove a note of type NOTE, which must be found, for register
711 number REGNO from INSN. Remove only one such note. */
714 remove_regno_note (rtx insn
, enum reg_note note
, unsigned int regno
)
716 rtx
*note_link
, this_rtx
;
718 note_link
= ®_NOTES (insn
);
719 for (this_rtx
= *note_link
; this_rtx
; this_rtx
= XEXP (this_rtx
, 1))
720 if (REG_NOTE_KIND (this_rtx
) == note
721 && REG_P (XEXP (this_rtx
, 0)) && REGNO (XEXP (this_rtx
, 0)) == regno
)
723 *note_link
= XEXP (this_rtx
, 1);
727 note_link
= &XEXP (this_rtx
, 1);
732 /* Find the hard register number of virtual register REG in REGSTACK.
733 The hard register number is relative to the top of the stack. -1 is
734 returned if the register is not found. */
737 get_hard_regnum (stack regstack
, rtx reg
)
741 gcc_assert (STACK_REG_P (reg
));
743 for (i
= regstack
->top
; i
>= 0; i
--)
744 if (regstack
->reg
[i
] == REGNO (reg
))
747 return i
>= 0 ? (FIRST_STACK_REG
+ regstack
->top
- i
) : -1;
750 /* Emit an insn to pop virtual register REG before or after INSN.
751 REGSTACK is the stack state after INSN and is updated to reflect this
752 pop. WHEN is either emit_insn_before or emit_insn_after. A pop insn
753 is represented as a SET whose destination is the register to be popped
754 and source is the top of stack. A death note for the top of stack
755 cases the movdf pattern to pop. */
758 emit_pop_insn (rtx insn
, stack regstack
, rtx reg
, enum emit_where where
)
760 rtx pop_insn
, pop_rtx
;
763 /* For complex types take care to pop both halves. These may survive in
764 CLOBBER and USE expressions. */
765 if (COMPLEX_MODE_P (GET_MODE (reg
)))
767 rtx reg1
= FP_MODE_REG (REGNO (reg
), DFmode
);
768 rtx reg2
= FP_MODE_REG (REGNO (reg
) + 1, DFmode
);
771 if (get_hard_regnum (regstack
, reg1
) >= 0)
772 pop_insn
= emit_pop_insn (insn
, regstack
, reg1
, where
);
773 if (get_hard_regnum (regstack
, reg2
) >= 0)
774 pop_insn
= emit_pop_insn (insn
, regstack
, reg2
, where
);
775 gcc_assert (pop_insn
);
779 hard_regno
= get_hard_regnum (regstack
, reg
);
781 gcc_assert (hard_regno
>= FIRST_STACK_REG
);
783 pop_rtx
= gen_rtx_SET (VOIDmode
, FP_MODE_REG (hard_regno
, DFmode
),
784 FP_MODE_REG (FIRST_STACK_REG
, DFmode
));
786 if (where
== EMIT_AFTER
)
787 pop_insn
= emit_insn_after (pop_rtx
, insn
);
789 pop_insn
= emit_insn_before (pop_rtx
, insn
);
791 add_reg_note (pop_insn
, REG_DEAD
, FP_MODE_REG (FIRST_STACK_REG
, DFmode
));
793 regstack
->reg
[regstack
->top
- (hard_regno
- FIRST_STACK_REG
)]
794 = regstack
->reg
[regstack
->top
];
796 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (reg
));
801 /* Emit an insn before or after INSN to swap virtual register REG with
802 the top of stack. REGSTACK is the stack state before the swap, and
803 is updated to reflect the swap. A swap insn is represented as a
804 PARALLEL of two patterns: each pattern moves one reg to the other.
806 If REG is already at the top of the stack, no insn is emitted. */
809 emit_swap_insn (rtx insn
, stack regstack
, rtx reg
)
813 int tmp
, other_reg
; /* swap regno temps */
814 rtx i1
; /* the stack-reg insn prior to INSN */
815 rtx i1set
= NULL_RTX
; /* the SET rtx within I1 */
817 hard_regno
= get_hard_regnum (regstack
, reg
);
819 if (hard_regno
== FIRST_STACK_REG
)
821 if (hard_regno
== -1)
823 /* Something failed if the register wasn't on the stack. If we had
824 malformed asms, we zapped the instruction itself, but that didn't
825 produce the same pattern of register sets as before. To prevent
826 further failure, adjust REGSTACK to include REG at TOP. */
827 gcc_assert (any_malformed_asm
);
828 regstack
->reg
[++regstack
->top
] = REGNO (reg
);
831 gcc_assert (hard_regno
>= FIRST_STACK_REG
);
833 other_reg
= regstack
->top
- (hard_regno
- FIRST_STACK_REG
);
835 tmp
= regstack
->reg
[other_reg
];
836 regstack
->reg
[other_reg
] = regstack
->reg
[regstack
->top
];
837 regstack
->reg
[regstack
->top
] = tmp
;
839 /* Find the previous insn involving stack regs, but don't pass a
842 if (current_block
&& insn
!= BB_HEAD (current_block
))
844 rtx tmp
= PREV_INSN (insn
);
845 rtx limit
= PREV_INSN (BB_HEAD (current_block
));
850 || NOTE_INSN_BASIC_BLOCK_P (tmp
)
851 || (NONJUMP_INSN_P (tmp
)
852 && stack_regs_mentioned (tmp
)))
857 tmp
= PREV_INSN (tmp
);
862 && (i1set
= single_set (i1
)) != NULL_RTX
)
864 rtx i1src
= *get_true_reg (&SET_SRC (i1set
));
865 rtx i1dest
= *get_true_reg (&SET_DEST (i1set
));
867 /* If the previous register stack push was from the reg we are to
868 swap with, omit the swap. */
870 if (REG_P (i1dest
) && REGNO (i1dest
) == FIRST_STACK_REG
872 && REGNO (i1src
) == (unsigned) hard_regno
- 1
873 && find_regno_note (i1
, REG_DEAD
, FIRST_STACK_REG
) == NULL_RTX
)
876 /* If the previous insn wrote to the reg we are to swap with,
879 if (REG_P (i1dest
) && REGNO (i1dest
) == (unsigned) hard_regno
880 && REG_P (i1src
) && REGNO (i1src
) == FIRST_STACK_REG
881 && find_regno_note (i1
, REG_DEAD
, FIRST_STACK_REG
) == NULL_RTX
)
885 /* Avoid emitting the swap if this is the first register stack insn
886 of the current_block. Instead update the current_block's stack_in
887 and let compensate edges take care of this for us. */
888 if (current_block
&& starting_stack_p
)
890 BLOCK_INFO (current_block
)->stack_in
= *regstack
;
891 starting_stack_p
= false;
895 swap_rtx
= gen_swapxf (FP_MODE_REG (hard_regno
, XFmode
),
896 FP_MODE_REG (FIRST_STACK_REG
, XFmode
));
899 emit_insn_after (swap_rtx
, i1
);
900 else if (current_block
)
901 emit_insn_before (swap_rtx
, BB_HEAD (current_block
));
903 emit_insn_before (swap_rtx
, insn
);
906 /* Emit an insns before INSN to swap virtual register SRC1 with
907 the top of stack and virtual register SRC2 with second stack
908 slot. REGSTACK is the stack state before the swaps, and
909 is updated to reflect the swaps. A swap insn is represented as a
910 PARALLEL of two patterns: each pattern moves one reg to the other.
912 If SRC1 and/or SRC2 are already at the right place, no swap insn
916 swap_to_top (rtx insn
, stack regstack
, rtx src1
, rtx src2
)
918 struct stack_def temp_stack
;
919 int regno
, j
, k
, temp
;
921 temp_stack
= *regstack
;
923 /* Place operand 1 at the top of stack. */
924 regno
= get_hard_regnum (&temp_stack
, src1
);
925 gcc_assert (regno
>= 0);
926 if (regno
!= FIRST_STACK_REG
)
928 k
= temp_stack
.top
- (regno
- FIRST_STACK_REG
);
931 temp
= temp_stack
.reg
[k
];
932 temp_stack
.reg
[k
] = temp_stack
.reg
[j
];
933 temp_stack
.reg
[j
] = temp
;
936 /* Place operand 2 next on the stack. */
937 regno
= get_hard_regnum (&temp_stack
, src2
);
938 gcc_assert (regno
>= 0);
939 if (regno
!= FIRST_STACK_REG
+ 1)
941 k
= temp_stack
.top
- (regno
- FIRST_STACK_REG
);
942 j
= temp_stack
.top
- 1;
944 temp
= temp_stack
.reg
[k
];
945 temp_stack
.reg
[k
] = temp_stack
.reg
[j
];
946 temp_stack
.reg
[j
] = temp
;
949 change_stack (insn
, regstack
, &temp_stack
, EMIT_BEFORE
);
952 /* Handle a move to or from a stack register in PAT, which is in INSN.
953 REGSTACK is the current stack. Return whether a control flow insn
954 was deleted in the process. */
957 move_for_stack_reg (rtx insn
, stack regstack
, rtx pat
)
959 rtx
*psrc
= get_true_reg (&SET_SRC (pat
));
960 rtx
*pdest
= get_true_reg (&SET_DEST (pat
));
963 bool control_flow_insn_deleted
= false;
965 src
= *psrc
; dest
= *pdest
;
967 if (STACK_REG_P (src
) && STACK_REG_P (dest
))
969 /* Write from one stack reg to another. If SRC dies here, then
970 just change the register mapping and delete the insn. */
972 note
= find_regno_note (insn
, REG_DEAD
, REGNO (src
));
977 /* If this is a no-op move, there must not be a REG_DEAD note. */
978 gcc_assert (REGNO (src
) != REGNO (dest
));
980 for (i
= regstack
->top
; i
>= 0; i
--)
981 if (regstack
->reg
[i
] == REGNO (src
))
984 /* The destination must be dead, or life analysis is borked. */
985 gcc_assert (get_hard_regnum (regstack
, dest
) < FIRST_STACK_REG
);
987 /* If the source is not live, this is yet another case of
988 uninitialized variables. Load up a NaN instead. */
990 return move_nan_for_stack_reg (insn
, regstack
, dest
);
992 /* It is possible that the dest is unused after this insn.
993 If so, just pop the src. */
995 if (find_regno_note (insn
, REG_UNUSED
, REGNO (dest
)))
996 emit_pop_insn (insn
, regstack
, src
, EMIT_AFTER
);
999 regstack
->reg
[i
] = REGNO (dest
);
1000 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (dest
));
1001 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (src
));
1004 control_flow_insn_deleted
|= control_flow_insn_p (insn
);
1006 return control_flow_insn_deleted
;
1009 /* The source reg does not die. */
1011 /* If this appears to be a no-op move, delete it, or else it
1012 will confuse the machine description output patterns. But if
1013 it is REG_UNUSED, we must pop the reg now, as per-insn processing
1014 for REG_UNUSED will not work for deleted insns. */
1016 if (REGNO (src
) == REGNO (dest
))
1018 if (find_regno_note (insn
, REG_UNUSED
, REGNO (dest
)))
1019 emit_pop_insn (insn
, regstack
, dest
, EMIT_AFTER
);
1021 control_flow_insn_deleted
|= control_flow_insn_p (insn
);
1023 return control_flow_insn_deleted
;
1026 /* The destination ought to be dead. */
1027 gcc_assert (get_hard_regnum (regstack
, dest
) < FIRST_STACK_REG
);
1029 replace_reg (psrc
, get_hard_regnum (regstack
, src
));
1031 regstack
->reg
[++regstack
->top
] = REGNO (dest
);
1032 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (dest
));
1033 replace_reg (pdest
, FIRST_STACK_REG
);
1035 else if (STACK_REG_P (src
))
1037 /* Save from a stack reg to MEM, or possibly integer reg. Since
1038 only top of stack may be saved, emit an exchange first if
1041 emit_swap_insn (insn
, regstack
, src
);
1043 note
= find_regno_note (insn
, REG_DEAD
, REGNO (src
));
1046 replace_reg (&XEXP (note
, 0), FIRST_STACK_REG
);
1048 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (src
));
1050 else if ((GET_MODE (src
) == XFmode
)
1051 && regstack
->top
< REG_STACK_SIZE
- 1)
1053 /* A 387 cannot write an XFmode value to a MEM without
1054 clobbering the source reg. The output code can handle
1055 this by reading back the value from the MEM.
1056 But it is more efficient to use a temp register if one is
1057 available. Push the source value here if the register
1058 stack is not full, and then write the value to memory via
1061 rtx top_stack_reg
= FP_MODE_REG (FIRST_STACK_REG
, GET_MODE (src
));
1063 push_rtx
= gen_movxf (top_stack_reg
, top_stack_reg
);
1064 emit_insn_before (push_rtx
, insn
);
1065 add_reg_note (insn
, REG_DEAD
, top_stack_reg
);
1068 replace_reg (psrc
, FIRST_STACK_REG
);
1072 rtx pat
= PATTERN (insn
);
1074 gcc_assert (STACK_REG_P (dest
));
1076 /* Load from MEM, or possibly integer REG or constant, into the
1077 stack regs. The actual target is always the top of the
1078 stack. The stack mapping is changed to reflect that DEST is
1079 now at top of stack. */
1081 /* The destination ought to be dead. However, there is a
1082 special case with i387 UNSPEC_TAN, where destination is live
1083 (an argument to fptan) but inherent load of 1.0 is modelled
1084 as a load from a constant. */
1085 if (GET_CODE (pat
) == PARALLEL
1086 && XVECLEN (pat
, 0) == 2
1087 && GET_CODE (XVECEXP (pat
, 0, 1)) == SET
1088 && GET_CODE (SET_SRC (XVECEXP (pat
, 0, 1))) == UNSPEC
1089 && XINT (SET_SRC (XVECEXP (pat
, 0, 1)), 1) == UNSPEC_TAN
)
1090 emit_swap_insn (insn
, regstack
, dest
);
1092 gcc_assert (get_hard_regnum (regstack
, dest
) < FIRST_STACK_REG
);
1094 gcc_assert (regstack
->top
< REG_STACK_SIZE
);
1096 regstack
->reg
[++regstack
->top
] = REGNO (dest
);
1097 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (dest
));
1098 replace_reg (pdest
, FIRST_STACK_REG
);
1101 return control_flow_insn_deleted
;
1104 /* A helper function which replaces INSN with a pattern that loads up
1105 a NaN into DEST, then invokes move_for_stack_reg. */
1108 move_nan_for_stack_reg (rtx insn
, stack regstack
, rtx dest
)
1112 dest
= FP_MODE_REG (REGNO (dest
), SFmode
);
1113 pat
= gen_rtx_SET (VOIDmode
, dest
, not_a_num
);
1114 PATTERN (insn
) = pat
;
1115 INSN_CODE (insn
) = -1;
1117 return move_for_stack_reg (insn
, regstack
, pat
);
1120 /* Swap the condition on a branch, if there is one. Return true if we
1121 found a condition to swap. False if the condition was not used as
1125 swap_rtx_condition_1 (rtx pat
)
1130 if (COMPARISON_P (pat
))
1132 PUT_CODE (pat
, swap_condition (GET_CODE (pat
)));
1137 fmt
= GET_RTX_FORMAT (GET_CODE (pat
));
1138 for (i
= GET_RTX_LENGTH (GET_CODE (pat
)) - 1; i
>= 0; i
--)
1144 for (j
= XVECLEN (pat
, i
) - 1; j
>= 0; j
--)
1145 r
|= swap_rtx_condition_1 (XVECEXP (pat
, i
, j
));
1147 else if (fmt
[i
] == 'e')
1148 r
|= swap_rtx_condition_1 (XEXP (pat
, i
));
1156 swap_rtx_condition (rtx insn
)
1158 rtx pat
= PATTERN (insn
);
1160 /* We're looking for a single set to cc0 or an HImode temporary. */
1162 if (GET_CODE (pat
) == SET
1163 && REG_P (SET_DEST (pat
))
1164 && REGNO (SET_DEST (pat
)) == FLAGS_REG
)
1166 insn
= next_flags_user (insn
);
1167 if (insn
== NULL_RTX
)
1169 pat
= PATTERN (insn
);
1172 /* See if this is, or ends in, a fnstsw. If so, we're not doing anything
1173 with the cc value right now. We may be able to search for one
1176 if (GET_CODE (pat
) == SET
1177 && GET_CODE (SET_SRC (pat
)) == UNSPEC
1178 && XINT (SET_SRC (pat
), 1) == UNSPEC_FNSTSW
)
1180 rtx dest
= SET_DEST (pat
);
1182 /* Search forward looking for the first use of this value.
1183 Stop at block boundaries. */
1184 while (insn
!= BB_END (current_block
))
1186 insn
= NEXT_INSN (insn
);
1187 if (INSN_P (insn
) && reg_mentioned_p (dest
, insn
))
1193 /* We haven't found it. */
1194 if (insn
== BB_END (current_block
))
1197 /* So we've found the insn using this value. If it is anything
1198 other than sahf or the value does not die (meaning we'd have
1199 to search further), then we must give up. */
1200 pat
= PATTERN (insn
);
1201 if (GET_CODE (pat
) != SET
1202 || GET_CODE (SET_SRC (pat
)) != UNSPEC
1203 || XINT (SET_SRC (pat
), 1) != UNSPEC_SAHF
1204 || ! dead_or_set_p (insn
, dest
))
1207 /* Now we are prepared to handle this as a normal cc0 setter. */
1208 insn
= next_flags_user (insn
);
1209 if (insn
== NULL_RTX
)
1211 pat
= PATTERN (insn
);
1214 if (swap_rtx_condition_1 (pat
))
1217 INSN_CODE (insn
) = -1;
1218 if (recog_memoized (insn
) == -1)
1220 /* In case the flags don't die here, recurse to try fix
1221 following user too. */
1222 else if (! dead_or_set_p (insn
, ix86_flags_rtx
))
1224 insn
= next_flags_user (insn
);
1225 if (!insn
|| !swap_rtx_condition (insn
))
1230 swap_rtx_condition_1 (pat
);
1238 /* Handle a comparison. Special care needs to be taken to avoid
1239 causing comparisons that a 387 cannot do correctly, such as EQ.
1241 Also, a pop insn may need to be emitted. The 387 does have an
1242 `fcompp' insn that can pop two regs, but it is sometimes too expensive
1243 to do this - a `fcomp' followed by a `fstpl %st(0)' may be easier to
1247 compare_for_stack_reg (rtx insn
, stack regstack
, rtx pat_src
)
1250 rtx src1_note
, src2_note
;
1252 src1
= get_true_reg (&XEXP (pat_src
, 0));
1253 src2
= get_true_reg (&XEXP (pat_src
, 1));
1255 /* ??? If fxch turns out to be cheaper than fstp, give priority to
1256 registers that die in this insn - move those to stack top first. */
1257 if ((! STACK_REG_P (*src1
)
1258 || (STACK_REG_P (*src2
)
1259 && get_hard_regnum (regstack
, *src2
) == FIRST_STACK_REG
))
1260 && swap_rtx_condition (insn
))
1263 temp
= XEXP (pat_src
, 0);
1264 XEXP (pat_src
, 0) = XEXP (pat_src
, 1);
1265 XEXP (pat_src
, 1) = temp
;
1267 src1
= get_true_reg (&XEXP (pat_src
, 0));
1268 src2
= get_true_reg (&XEXP (pat_src
, 1));
1270 INSN_CODE (insn
) = -1;
1273 /* We will fix any death note later. */
1275 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1277 if (STACK_REG_P (*src2
))
1278 src2_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src2
));
1280 src2_note
= NULL_RTX
;
1282 emit_swap_insn (insn
, regstack
, *src1
);
1284 replace_reg (src1
, FIRST_STACK_REG
);
1286 if (STACK_REG_P (*src2
))
1287 replace_reg (src2
, get_hard_regnum (regstack
, *src2
));
1291 pop_stack (regstack
, REGNO (XEXP (src1_note
, 0)));
1292 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1295 /* If the second operand dies, handle that. But if the operands are
1296 the same stack register, don't bother, because only one death is
1297 needed, and it was just handled. */
1300 && ! (STACK_REG_P (*src1
) && STACK_REG_P (*src2
)
1301 && REGNO (*src1
) == REGNO (*src2
)))
1303 /* As a special case, two regs may die in this insn if src2 is
1304 next to top of stack and the top of stack also dies. Since
1305 we have already popped src1, "next to top of stack" is really
1306 at top (FIRST_STACK_REG) now. */
1308 if (get_hard_regnum (regstack
, XEXP (src2_note
, 0)) == FIRST_STACK_REG
1311 pop_stack (regstack
, REGNO (XEXP (src2_note
, 0)));
1312 replace_reg (&XEXP (src2_note
, 0), FIRST_STACK_REG
+ 1);
1316 /* The 386 can only represent death of the first operand in
1317 the case handled above. In all other cases, emit a separate
1318 pop and remove the death note from here. */
1320 /* link_cc0_insns (insn); */
1322 remove_regno_note (insn
, REG_DEAD
, REGNO (XEXP (src2_note
, 0)));
1324 emit_pop_insn (insn
, regstack
, XEXP (src2_note
, 0),
1330 /* Substitute new registers in PAT, which is part of INSN. REGSTACK
1331 is the current register layout. Return whether a control flow insn
1332 was deleted in the process. */
1335 subst_stack_regs_pat (rtx insn
, stack regstack
, rtx pat
)
1338 bool control_flow_insn_deleted
= false;
1340 switch (GET_CODE (pat
))
1343 /* Deaths in USE insns can happen in non optimizing compilation.
1344 Handle them by popping the dying register. */
1345 src
= get_true_reg (&XEXP (pat
, 0));
1346 if (STACK_REG_P (*src
)
1347 && find_regno_note (insn
, REG_DEAD
, REGNO (*src
)))
1349 /* USEs are ignored for liveness information so USEs of dead
1350 register might happen. */
1351 if (TEST_HARD_REG_BIT (regstack
->reg_set
, REGNO (*src
)))
1352 emit_pop_insn (insn
, regstack
, *src
, EMIT_AFTER
);
1353 return control_flow_insn_deleted
;
1355 /* Uninitialized USE might happen for functions returning uninitialized
1356 value. We will properly initialize the USE on the edge to EXIT_BLOCK,
1357 so it is safe to ignore the use here. This is consistent with behavior
1358 of dataflow analyzer that ignores USE too. (This also imply that
1359 forcibly initializing the register to NaN here would lead to ICE later,
1360 since the REG_DEAD notes are not issued.) */
1367 dest
= get_true_reg (&XEXP (pat
, 0));
1368 if (STACK_REG_P (*dest
))
1370 note
= find_reg_note (insn
, REG_DEAD
, *dest
);
1372 if (pat
!= PATTERN (insn
))
1374 /* The fix_truncdi_1 pattern wants to be able to allocate
1375 its own scratch register. It does this by clobbering
1376 an fp reg so that it is assured of an empty reg-stack
1377 register. If the register is live, kill it now.
1378 Remove the DEAD/UNUSED note so we don't try to kill it
1382 emit_pop_insn (insn
, regstack
, *dest
, EMIT_BEFORE
);
1385 note
= find_reg_note (insn
, REG_UNUSED
, *dest
);
1388 remove_note (insn
, note
);
1389 replace_reg (dest
, FIRST_STACK_REG
+ 1);
1393 /* A top-level clobber with no REG_DEAD, and no hard-regnum
1394 indicates an uninitialized value. Because reload removed
1395 all other clobbers, this must be due to a function
1396 returning without a value. Load up a NaN. */
1401 if (COMPLEX_MODE_P (GET_MODE (t
)))
1403 rtx u
= FP_MODE_REG (REGNO (t
) + 1, SFmode
);
1404 if (get_hard_regnum (regstack
, u
) == -1)
1406 rtx pat2
= gen_rtx_CLOBBER (VOIDmode
, u
);
1407 rtx insn2
= emit_insn_before (pat2
, insn
);
1408 control_flow_insn_deleted
1409 |= move_nan_for_stack_reg (insn2
, regstack
, u
);
1412 if (get_hard_regnum (regstack
, t
) == -1)
1413 control_flow_insn_deleted
1414 |= move_nan_for_stack_reg (insn
, regstack
, t
);
1423 rtx
*src1
= (rtx
*) 0, *src2
;
1424 rtx src1_note
, src2_note
;
1427 dest
= get_true_reg (&SET_DEST (pat
));
1428 src
= get_true_reg (&SET_SRC (pat
));
1429 pat_src
= SET_SRC (pat
);
1431 /* See if this is a `movM' pattern, and handle elsewhere if so. */
1432 if (STACK_REG_P (*src
)
1433 || (STACK_REG_P (*dest
)
1434 && (REG_P (*src
) || MEM_P (*src
)
1435 || GET_CODE (*src
) == CONST_DOUBLE
)))
1437 control_flow_insn_deleted
|= move_for_stack_reg (insn
, regstack
, pat
);
1441 switch (GET_CODE (pat_src
))
1444 compare_for_stack_reg (insn
, regstack
, pat_src
);
1450 for (count
= hard_regno_nregs
[REGNO (*dest
)][GET_MODE (*dest
)];
1453 regstack
->reg
[++regstack
->top
] = REGNO (*dest
) + count
;
1454 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
) + count
);
1457 replace_reg (dest
, FIRST_STACK_REG
);
1461 /* This is a `tstM2' case. */
1462 gcc_assert (*dest
== cc0_rtx
);
1467 case FLOAT_TRUNCATE
:
1471 /* These insns only operate on the top of the stack. DEST might
1472 be cc0_rtx if we're processing a tstM pattern. Also, it's
1473 possible that the tstM case results in a REG_DEAD note on the
1477 src1
= get_true_reg (&XEXP (pat_src
, 0));
1479 emit_swap_insn (insn
, regstack
, *src1
);
1481 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1483 if (STACK_REG_P (*dest
))
1484 replace_reg (dest
, FIRST_STACK_REG
);
1488 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1490 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (*src1
));
1493 replace_reg (src1
, FIRST_STACK_REG
);
1498 /* On i386, reversed forms of subM3 and divM3 exist for
1499 MODE_FLOAT, so the same code that works for addM3 and mulM3
1503 /* These insns can accept the top of stack as a destination
1504 from a stack reg or mem, or can use the top of stack as a
1505 source and some other stack register (possibly top of stack)
1506 as a destination. */
1508 src1
= get_true_reg (&XEXP (pat_src
, 0));
1509 src2
= get_true_reg (&XEXP (pat_src
, 1));
1511 /* We will fix any death note later. */
1513 if (STACK_REG_P (*src1
))
1514 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1516 src1_note
= NULL_RTX
;
1517 if (STACK_REG_P (*src2
))
1518 src2_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src2
));
1520 src2_note
= NULL_RTX
;
1522 /* If either operand is not a stack register, then the dest
1523 must be top of stack. */
1525 if (! STACK_REG_P (*src1
) || ! STACK_REG_P (*src2
))
1526 emit_swap_insn (insn
, regstack
, *dest
);
1529 /* Both operands are REG. If neither operand is already
1530 at the top of stack, choose to make the one that is the
1531 dest the new top of stack. */
1533 int src1_hard_regnum
, src2_hard_regnum
;
1535 src1_hard_regnum
= get_hard_regnum (regstack
, *src1
);
1536 src2_hard_regnum
= get_hard_regnum (regstack
, *src2
);
1538 /* If the source is not live, this is yet another case of
1539 uninitialized variables. Load up a NaN instead. */
1540 if (src1_hard_regnum
== -1)
1542 rtx pat2
= gen_rtx_CLOBBER (VOIDmode
, *src1
);
1543 rtx insn2
= emit_insn_before (pat2
, insn
);
1544 control_flow_insn_deleted
1545 |= move_nan_for_stack_reg (insn2
, regstack
, *src1
);
1547 if (src2_hard_regnum
== -1)
1549 rtx pat2
= gen_rtx_CLOBBER (VOIDmode
, *src2
);
1550 rtx insn2
= emit_insn_before (pat2
, insn
);
1551 control_flow_insn_deleted
1552 |= move_nan_for_stack_reg (insn2
, regstack
, *src2
);
1555 if (src1_hard_regnum
!= FIRST_STACK_REG
1556 && src2_hard_regnum
!= FIRST_STACK_REG
)
1557 emit_swap_insn (insn
, regstack
, *dest
);
1560 if (STACK_REG_P (*src1
))
1561 replace_reg (src1
, get_hard_regnum (regstack
, *src1
));
1562 if (STACK_REG_P (*src2
))
1563 replace_reg (src2
, get_hard_regnum (regstack
, *src2
));
1567 rtx src1_reg
= XEXP (src1_note
, 0);
1569 /* If the register that dies is at the top of stack, then
1570 the destination is somewhere else - merely substitute it.
1571 But if the reg that dies is not at top of stack, then
1572 move the top of stack to the dead reg, as though we had
1573 done the insn and then a store-with-pop. */
1575 if (REGNO (src1_reg
) == regstack
->reg
[regstack
->top
])
1577 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1578 replace_reg (dest
, get_hard_regnum (regstack
, *dest
));
1582 int regno
= get_hard_regnum (regstack
, src1_reg
);
1584 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1585 replace_reg (dest
, regno
);
1587 regstack
->reg
[regstack
->top
- (regno
- FIRST_STACK_REG
)]
1588 = regstack
->reg
[regstack
->top
];
1591 CLEAR_HARD_REG_BIT (regstack
->reg_set
,
1592 REGNO (XEXP (src1_note
, 0)));
1593 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1598 rtx src2_reg
= XEXP (src2_note
, 0);
1599 if (REGNO (src2_reg
) == regstack
->reg
[regstack
->top
])
1601 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1602 replace_reg (dest
, get_hard_regnum (regstack
, *dest
));
1606 int regno
= get_hard_regnum (regstack
, src2_reg
);
1608 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1609 replace_reg (dest
, regno
);
1611 regstack
->reg
[regstack
->top
- (regno
- FIRST_STACK_REG
)]
1612 = regstack
->reg
[regstack
->top
];
1615 CLEAR_HARD_REG_BIT (regstack
->reg_set
,
1616 REGNO (XEXP (src2_note
, 0)));
1617 replace_reg (&XEXP (src2_note
, 0), FIRST_STACK_REG
);
1622 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1623 replace_reg (dest
, get_hard_regnum (regstack
, *dest
));
1626 /* Keep operand 1 matching with destination. */
1627 if (COMMUTATIVE_ARITH_P (pat_src
)
1628 && REG_P (*src1
) && REG_P (*src2
)
1629 && REGNO (*src1
) != REGNO (*dest
))
1631 int tmp
= REGNO (*src1
);
1632 replace_reg (src1
, REGNO (*src2
));
1633 replace_reg (src2
, tmp
);
1638 switch (XINT (pat_src
, 1))
1642 case UNSPEC_FIST_FLOOR
:
1643 case UNSPEC_FIST_CEIL
:
1645 /* These insns only operate on the top of the stack. */
1647 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1648 emit_swap_insn (insn
, regstack
, *src1
);
1650 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1652 if (STACK_REG_P (*dest
))
1653 replace_reg (dest
, FIRST_STACK_REG
);
1657 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1659 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (*src1
));
1662 replace_reg (src1
, FIRST_STACK_REG
);
1667 /* This insn 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 replace_reg (src1
, FIRST_STACK_REG
);
1678 remove_regno_note (insn
, REG_DEAD
,
1679 REGNO (XEXP (src1_note
, 0)));
1680 emit_pop_insn (insn
, regstack
, XEXP (src1_note
, 0),
1688 case UNSPEC_FRNDINT
:
1691 case UNSPEC_FRNDINT_FLOOR
:
1692 case UNSPEC_FRNDINT_CEIL
:
1693 case UNSPEC_FRNDINT_TRUNC
:
1694 case UNSPEC_FRNDINT_MASK_PM
:
1696 /* Above insns operate on the top of the stack. */
1698 case UNSPEC_SINCOS_COS
:
1699 case UNSPEC_XTRACT_FRACT
:
1701 /* Above insns operate on the top two stack slots,
1702 first part of one input, double output insn. */
1704 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1706 emit_swap_insn (insn
, regstack
, *src1
);
1708 /* Input should never die, it is replaced with output. */
1709 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1710 gcc_assert (!src1_note
);
1712 if (STACK_REG_P (*dest
))
1713 replace_reg (dest
, FIRST_STACK_REG
);
1715 replace_reg (src1
, FIRST_STACK_REG
);
1718 case UNSPEC_SINCOS_SIN
:
1719 case UNSPEC_XTRACT_EXP
:
1721 /* These insns operate on the top two stack slots,
1722 second part of one input, double output insn. */
1729 /* For UNSPEC_TAN, regstack->top is already increased
1730 by inherent load of constant 1.0. */
1732 /* Output value is generated in the second stack slot.
1733 Move current value from second slot to the top. */
1734 regstack
->reg
[regstack
->top
]
1735 = regstack
->reg
[regstack
->top
- 1];
1737 gcc_assert (STACK_REG_P (*dest
));
1739 regstack
->reg
[regstack
->top
- 1] = REGNO (*dest
);
1740 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1741 replace_reg (dest
, FIRST_STACK_REG
+ 1);
1743 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1745 replace_reg (src1
, FIRST_STACK_REG
);
1750 case UNSPEC_FYL2XP1
:
1751 /* These insns operate on the top two stack slots. */
1753 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1754 src2
= get_true_reg (&XVECEXP (pat_src
, 0, 1));
1756 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1757 src2_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src2
));
1759 swap_to_top (insn
, regstack
, *src1
, *src2
);
1761 replace_reg (src1
, FIRST_STACK_REG
);
1762 replace_reg (src2
, FIRST_STACK_REG
+ 1);
1765 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1767 replace_reg (&XEXP (src2_note
, 0), FIRST_STACK_REG
+ 1);
1769 /* Pop both input operands from the stack. */
1770 CLEAR_HARD_REG_BIT (regstack
->reg_set
,
1771 regstack
->reg
[regstack
->top
]);
1772 CLEAR_HARD_REG_BIT (regstack
->reg_set
,
1773 regstack
->reg
[regstack
->top
- 1]);
1776 /* Push the result back onto the stack. */
1777 regstack
->reg
[++regstack
->top
] = REGNO (*dest
);
1778 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1779 replace_reg (dest
, FIRST_STACK_REG
);
1782 case UNSPEC_FSCALE_FRACT
:
1783 case UNSPEC_FPREM_F
:
1784 case UNSPEC_FPREM1_F
:
1785 /* These insns operate on the top two stack slots,
1786 first part of double input, double output insn. */
1788 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1789 src2
= get_true_reg (&XVECEXP (pat_src
, 0, 1));
1791 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1792 src2_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src2
));
1794 /* Inputs should never die, they are
1795 replaced with outputs. */
1796 gcc_assert (!src1_note
);
1797 gcc_assert (!src2_note
);
1799 swap_to_top (insn
, regstack
, *src1
, *src2
);
1801 /* Push the result back onto stack. Empty stack slot
1802 will be filled in second part of insn. */
1803 if (STACK_REG_P (*dest
))
1805 regstack
->reg
[regstack
->top
] = REGNO (*dest
);
1806 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1807 replace_reg (dest
, FIRST_STACK_REG
);
1810 replace_reg (src1
, FIRST_STACK_REG
);
1811 replace_reg (src2
, FIRST_STACK_REG
+ 1);
1814 case UNSPEC_FSCALE_EXP
:
1815 case UNSPEC_FPREM_U
:
1816 case UNSPEC_FPREM1_U
:
1817 /* These insns operate on the top two stack slots,
1818 second part of double input, double output insn. */
1820 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1821 src2
= get_true_reg (&XVECEXP (pat_src
, 0, 1));
1823 /* Push the result back onto stack. Fill empty slot from
1824 first part of insn and fix top of stack pointer. */
1825 if (STACK_REG_P (*dest
))
1827 regstack
->reg
[regstack
->top
- 1] = REGNO (*dest
);
1828 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1829 replace_reg (dest
, FIRST_STACK_REG
+ 1);
1832 replace_reg (src1
, FIRST_STACK_REG
);
1833 replace_reg (src2
, FIRST_STACK_REG
+ 1);
1836 case UNSPEC_C2_FLAG
:
1837 /* This insn operates on the top two stack slots,
1838 third part of C2 setting double input insn. */
1840 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1841 src2
= get_true_reg (&XVECEXP (pat_src
, 0, 1));
1843 replace_reg (src1
, FIRST_STACK_REG
);
1844 replace_reg (src2
, FIRST_STACK_REG
+ 1);
1848 /* (unspec [(unspec [(compare)] UNSPEC_FNSTSW)] UNSPEC_SAHF)
1849 The combination matches the PPRO fcomi instruction. */
1851 pat_src
= XVECEXP (pat_src
, 0, 0);
1852 gcc_assert (GET_CODE (pat_src
) == UNSPEC
);
1853 gcc_assert (XINT (pat_src
, 1) == UNSPEC_FNSTSW
);
1857 /* Combined fcomp+fnstsw generated for doing well with
1858 CSE. When optimizing this would have been broken
1861 pat_src
= XVECEXP (pat_src
, 0, 0);
1862 gcc_assert (GET_CODE (pat_src
) == COMPARE
);
1864 compare_for_stack_reg (insn
, regstack
, pat_src
);
1873 /* This insn requires the top of stack to be the destination. */
1875 src1
= get_true_reg (&XEXP (pat_src
, 1));
1876 src2
= get_true_reg (&XEXP (pat_src
, 2));
1878 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1879 src2_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src2
));
1881 /* If the comparison operator is an FP comparison operator,
1882 it is handled correctly by compare_for_stack_reg () who
1883 will move the destination to the top of stack. But if the
1884 comparison operator is not an FP comparison operator, we
1885 have to handle it here. */
1886 if (get_hard_regnum (regstack
, *dest
) >= FIRST_STACK_REG
1887 && REGNO (*dest
) != regstack
->reg
[regstack
->top
])
1889 /* In case one of operands is the top of stack and the operands
1890 dies, it is safe to make it the destination operand by
1891 reversing the direction of cmove and avoid fxch. */
1892 if ((REGNO (*src1
) == regstack
->reg
[regstack
->top
]
1894 || (REGNO (*src2
) == regstack
->reg
[regstack
->top
]
1897 int idx1
= (get_hard_regnum (regstack
, *src1
)
1899 int idx2
= (get_hard_regnum (regstack
, *src2
)
1902 /* Make reg-stack believe that the operands are already
1903 swapped on the stack */
1904 regstack
->reg
[regstack
->top
- idx1
] = REGNO (*src2
);
1905 regstack
->reg
[regstack
->top
- idx2
] = REGNO (*src1
);
1907 /* Reverse condition to compensate the operand swap.
1908 i386 do have comparison always reversible. */
1909 PUT_CODE (XEXP (pat_src
, 0),
1910 reversed_comparison_code (XEXP (pat_src
, 0), insn
));
1913 emit_swap_insn (insn
, regstack
, *dest
);
1921 src_note
[1] = src1_note
;
1922 src_note
[2] = src2_note
;
1924 if (STACK_REG_P (*src1
))
1925 replace_reg (src1
, get_hard_regnum (regstack
, *src1
));
1926 if (STACK_REG_P (*src2
))
1927 replace_reg (src2
, get_hard_regnum (regstack
, *src2
));
1929 for (i
= 1; i
<= 2; i
++)
1932 int regno
= REGNO (XEXP (src_note
[i
], 0));
1934 /* If the register that dies is not at the top of
1935 stack, then move the top of stack to the dead reg.
1936 Top of stack should never die, as it is the
1938 gcc_assert (regno
!= regstack
->reg
[regstack
->top
]);
1939 remove_regno_note (insn
, REG_DEAD
, regno
);
1940 emit_pop_insn (insn
, regstack
, XEXP (src_note
[i
], 0),
1945 /* Make dest the top of stack. Add dest to regstack if
1947 if (get_hard_regnum (regstack
, *dest
) < FIRST_STACK_REG
)
1948 regstack
->reg
[++regstack
->top
] = REGNO (*dest
);
1949 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1950 replace_reg (dest
, FIRST_STACK_REG
);
1963 return control_flow_insn_deleted
;
1966 /* Substitute hard regnums for any stack regs in INSN, which has
1967 N_INPUTS inputs and N_OUTPUTS outputs. REGSTACK is the stack info
1968 before the insn, and is updated with changes made here.
1970 There are several requirements and assumptions about the use of
1971 stack-like regs in asm statements. These rules are enforced by
1972 record_asm_stack_regs; see comments there for details. Any
1973 asm_operands left in the RTL at this point may be assume to meet the
1974 requirements, since record_asm_stack_regs removes any problem asm. */
1977 subst_asm_stack_regs (rtx insn
, stack regstack
)
1979 rtx body
= PATTERN (insn
);
1982 rtx
*note_reg
; /* Array of note contents */
1983 rtx
**note_loc
; /* Address of REG field of each note */
1984 enum reg_note
*note_kind
; /* The type of each note */
1986 rtx
*clobber_reg
= 0;
1987 rtx
**clobber_loc
= 0;
1989 struct stack_def temp_stack
;
1994 int n_inputs
, n_outputs
;
1996 if (! check_asm_stack_operands (insn
))
1999 /* Find out what the constraints required. If no constraint
2000 alternative matches, that is a compiler bug: we should have caught
2001 such an insn in check_asm_stack_operands. */
2002 extract_insn (insn
);
2003 constrain_operands (1);
2004 alt
= which_alternative
;
2006 preprocess_constraints ();
2008 n_inputs
= get_asm_operand_n_inputs (body
);
2009 n_outputs
= recog_data
.n_operands
- n_inputs
;
2011 gcc_assert (alt
>= 0);
2013 /* Strip SUBREGs here to make the following code simpler. */
2014 for (i
= 0; i
< recog_data
.n_operands
; i
++)
2015 if (GET_CODE (recog_data
.operand
[i
]) == SUBREG
2016 && REG_P (SUBREG_REG (recog_data
.operand
[i
])))
2018 recog_data
.operand_loc
[i
] = & SUBREG_REG (recog_data
.operand
[i
]);
2019 recog_data
.operand
[i
] = SUBREG_REG (recog_data
.operand
[i
]);
2022 /* Set up NOTE_REG, NOTE_LOC and NOTE_KIND. */
2024 for (i
= 0, note
= REG_NOTES (insn
); note
; note
= XEXP (note
, 1))
2027 note_reg
= XALLOCAVEC (rtx
, i
);
2028 note_loc
= XALLOCAVEC (rtx
*, i
);
2029 note_kind
= XALLOCAVEC (enum reg_note
, i
);
2032 for (note
= REG_NOTES (insn
); note
; note
= XEXP (note
, 1))
2034 rtx reg
= XEXP (note
, 0);
2035 rtx
*loc
= & XEXP (note
, 0);
2037 if (GET_CODE (reg
) == SUBREG
&& REG_P (SUBREG_REG (reg
)))
2039 loc
= & SUBREG_REG (reg
);
2040 reg
= SUBREG_REG (reg
);
2043 if (STACK_REG_P (reg
)
2044 && (REG_NOTE_KIND (note
) == REG_DEAD
2045 || REG_NOTE_KIND (note
) == REG_UNUSED
))
2047 note_reg
[n_notes
] = reg
;
2048 note_loc
[n_notes
] = loc
;
2049 note_kind
[n_notes
] = REG_NOTE_KIND (note
);
2054 /* Set up CLOBBER_REG and CLOBBER_LOC. */
2058 if (GET_CODE (body
) == PARALLEL
)
2060 clobber_reg
= XALLOCAVEC (rtx
, XVECLEN (body
, 0));
2061 clobber_loc
= XALLOCAVEC (rtx
*, XVECLEN (body
, 0));
2063 for (i
= 0; i
< XVECLEN (body
, 0); i
++)
2064 if (GET_CODE (XVECEXP (body
, 0, i
)) == CLOBBER
)
2066 rtx clobber
= XVECEXP (body
, 0, i
);
2067 rtx reg
= XEXP (clobber
, 0);
2068 rtx
*loc
= & XEXP (clobber
, 0);
2070 if (GET_CODE (reg
) == SUBREG
&& REG_P (SUBREG_REG (reg
)))
2072 loc
= & SUBREG_REG (reg
);
2073 reg
= SUBREG_REG (reg
);
2076 if (STACK_REG_P (reg
))
2078 clobber_reg
[n_clobbers
] = reg
;
2079 clobber_loc
[n_clobbers
] = loc
;
2085 temp_stack
= *regstack
;
2087 /* Put the input regs into the desired place in TEMP_STACK. */
2089 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
2090 if (STACK_REG_P (recog_data
.operand
[i
])
2091 && reg_class_subset_p (recog_op_alt
[i
][alt
].cl
,
2093 && recog_op_alt
[i
][alt
].cl
!= FLOAT_REGS
)
2095 /* If an operand needs to be in a particular reg in
2096 FLOAT_REGS, the constraint was either 't' or 'u'. Since
2097 these constraints are for single register classes, and
2098 reload guaranteed that operand[i] is already in that class,
2099 we can just use REGNO (recog_data.operand[i]) to know which
2100 actual reg this operand needs to be in. */
2102 int regno
= get_hard_regnum (&temp_stack
, recog_data
.operand
[i
]);
2104 gcc_assert (regno
>= 0);
2106 if ((unsigned int) regno
!= REGNO (recog_data
.operand
[i
]))
2108 /* recog_data.operand[i] is not in the right place. Find
2109 it and swap it with whatever is already in I's place.
2110 K is where recog_data.operand[i] is now. J is where it
2114 k
= temp_stack
.top
- (regno
- FIRST_STACK_REG
);
2116 - (REGNO (recog_data
.operand
[i
]) - FIRST_STACK_REG
));
2118 temp
= temp_stack
.reg
[k
];
2119 temp_stack
.reg
[k
] = temp_stack
.reg
[j
];
2120 temp_stack
.reg
[j
] = temp
;
2124 /* Emit insns before INSN to make sure the reg-stack is in the right
2127 change_stack (insn
, regstack
, &temp_stack
, EMIT_BEFORE
);
2129 /* Make the needed input register substitutions. Do death notes and
2130 clobbers too, because these are for inputs, not outputs. */
2132 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
2133 if (STACK_REG_P (recog_data
.operand
[i
]))
2135 int regnum
= get_hard_regnum (regstack
, recog_data
.operand
[i
]);
2137 gcc_assert (regnum
>= 0);
2139 replace_reg (recog_data
.operand_loc
[i
], regnum
);
2142 for (i
= 0; i
< n_notes
; i
++)
2143 if (note_kind
[i
] == REG_DEAD
)
2145 int regnum
= get_hard_regnum (regstack
, note_reg
[i
]);
2147 gcc_assert (regnum
>= 0);
2149 replace_reg (note_loc
[i
], regnum
);
2152 for (i
= 0; i
< n_clobbers
; i
++)
2154 /* It's OK for a CLOBBER to reference a reg that is not live.
2155 Don't try to replace it in that case. */
2156 int regnum
= get_hard_regnum (regstack
, clobber_reg
[i
]);
2160 /* Sigh - clobbers always have QImode. But replace_reg knows
2161 that these regs can't be MODE_INT and will assert. Just put
2162 the right reg there without calling replace_reg. */
2164 *clobber_loc
[i
] = FP_MODE_REG (regnum
, DFmode
);
2168 /* Now remove from REGSTACK any inputs that the asm implicitly popped. */
2170 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
2171 if (STACK_REG_P (recog_data
.operand
[i
]))
2173 /* An input reg is implicitly popped if it is tied to an
2174 output, or if there is a CLOBBER for it. */
2177 for (j
= 0; j
< n_clobbers
; j
++)
2178 if (operands_match_p (clobber_reg
[j
], recog_data
.operand
[i
]))
2181 if (j
< n_clobbers
|| recog_op_alt
[i
][alt
].matches
>= 0)
2183 /* recog_data.operand[i] might not be at the top of stack.
2184 But that's OK, because all we need to do is pop the
2185 right number of regs off of the top of the reg-stack.
2186 record_asm_stack_regs guaranteed that all implicitly
2187 popped regs were grouped at the top of the reg-stack. */
2189 CLEAR_HARD_REG_BIT (regstack
->reg_set
,
2190 regstack
->reg
[regstack
->top
]);
2195 /* Now add to REGSTACK any outputs that the asm implicitly pushed.
2196 Note that there isn't any need to substitute register numbers.
2197 ??? Explain why this is true. */
2199 for (i
= LAST_STACK_REG
; i
>= FIRST_STACK_REG
; i
--)
2201 /* See if there is an output for this hard reg. */
2204 for (j
= 0; j
< n_outputs
; j
++)
2205 if (STACK_REG_P (recog_data
.operand
[j
])
2206 && REGNO (recog_data
.operand
[j
]) == (unsigned) i
)
2208 regstack
->reg
[++regstack
->top
] = i
;
2209 SET_HARD_REG_BIT (regstack
->reg_set
, i
);
2214 /* Now emit a pop insn for any REG_UNUSED output, or any REG_DEAD
2215 input that the asm didn't implicitly pop. If the asm didn't
2216 implicitly pop an input reg, that reg will still be live.
2218 Note that we can't use find_regno_note here: the register numbers
2219 in the death notes have already been substituted. */
2221 for (i
= 0; i
< n_outputs
; i
++)
2222 if (STACK_REG_P (recog_data
.operand
[i
]))
2226 for (j
= 0; j
< n_notes
; j
++)
2227 if (REGNO (recog_data
.operand
[i
]) == REGNO (note_reg
[j
])
2228 && note_kind
[j
] == REG_UNUSED
)
2230 insn
= emit_pop_insn (insn
, regstack
, recog_data
.operand
[i
],
2236 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
2237 if (STACK_REG_P (recog_data
.operand
[i
]))
2241 for (j
= 0; j
< n_notes
; j
++)
2242 if (REGNO (recog_data
.operand
[i
]) == REGNO (note_reg
[j
])
2243 && note_kind
[j
] == REG_DEAD
2244 && TEST_HARD_REG_BIT (regstack
->reg_set
,
2245 REGNO (recog_data
.operand
[i
])))
2247 insn
= emit_pop_insn (insn
, regstack
, recog_data
.operand
[i
],
2254 /* Substitute stack hard reg numbers for stack virtual registers in
2255 INSN. Non-stack register numbers are not changed. REGSTACK is the
2256 current stack content. Insns may be emitted as needed to arrange the
2257 stack for the 387 based on the contents of the insn. Return whether
2258 a control flow insn was deleted in the process. */
2261 subst_stack_regs (rtx insn
, stack regstack
)
2263 rtx
*note_link
, note
;
2264 bool control_flow_insn_deleted
= false;
2269 int top
= regstack
->top
;
2271 /* If there are any floating point parameters to be passed in
2272 registers for this call, make sure they are in the right
2277 straighten_stack (insn
, regstack
);
2279 /* Now mark the arguments as dead after the call. */
2281 while (regstack
->top
>= 0)
2283 CLEAR_HARD_REG_BIT (regstack
->reg_set
, FIRST_STACK_REG
+ regstack
->top
);
2289 /* Do the actual substitution if any stack regs are mentioned.
2290 Since we only record whether entire insn mentions stack regs, and
2291 subst_stack_regs_pat only works for patterns that contain stack regs,
2292 we must check each pattern in a parallel here. A call_value_pop could
2295 if (stack_regs_mentioned (insn
))
2297 int n_operands
= asm_noperands (PATTERN (insn
));
2298 if (n_operands
>= 0)
2300 /* This insn is an `asm' with operands. Decode the operands,
2301 decide how many are inputs, and do register substitution.
2302 Any REG_UNUSED notes will be handled by subst_asm_stack_regs. */
2304 subst_asm_stack_regs (insn
, regstack
);
2305 return control_flow_insn_deleted
;
2308 if (GET_CODE (PATTERN (insn
)) == PARALLEL
)
2309 for (i
= 0; i
< XVECLEN (PATTERN (insn
), 0); i
++)
2311 if (stack_regs_mentioned_p (XVECEXP (PATTERN (insn
), 0, i
)))
2313 if (GET_CODE (XVECEXP (PATTERN (insn
), 0, i
)) == CLOBBER
)
2314 XVECEXP (PATTERN (insn
), 0, i
)
2315 = shallow_copy_rtx (XVECEXP (PATTERN (insn
), 0, i
));
2316 control_flow_insn_deleted
2317 |= subst_stack_regs_pat (insn
, regstack
,
2318 XVECEXP (PATTERN (insn
), 0, i
));
2322 control_flow_insn_deleted
2323 |= subst_stack_regs_pat (insn
, regstack
, PATTERN (insn
));
2326 /* subst_stack_regs_pat may have deleted a no-op insn. If so, any
2327 REG_UNUSED will already have been dealt with, so just return. */
2329 if (NOTE_P (insn
) || INSN_DELETED_P (insn
))
2330 return control_flow_insn_deleted
;
2332 /* If this a noreturn call, we can't insert pop insns after it.
2333 Instead, reset the stack state to empty. */
2335 && find_reg_note (insn
, REG_NORETURN
, NULL
))
2338 CLEAR_HARD_REG_SET (regstack
->reg_set
);
2339 return control_flow_insn_deleted
;
2342 /* If there is a REG_UNUSED note on a stack register on this insn,
2343 the indicated reg must be popped. The REG_UNUSED note is removed,
2344 since the form of the newly emitted pop insn references the reg,
2345 making it no longer `unset'. */
2347 note_link
= ®_NOTES (insn
);
2348 for (note
= *note_link
; note
; note
= XEXP (note
, 1))
2349 if (REG_NOTE_KIND (note
) == REG_UNUSED
&& STACK_REG_P (XEXP (note
, 0)))
2351 *note_link
= XEXP (note
, 1);
2352 insn
= emit_pop_insn (insn
, regstack
, XEXP (note
, 0), EMIT_AFTER
);
2355 note_link
= &XEXP (note
, 1);
2357 return control_flow_insn_deleted
;
2360 /* Change the organization of the stack so that it fits a new basic
2361 block. Some registers might have to be popped, but there can never be
2362 a register live in the new block that is not now live.
2364 Insert any needed insns before or after INSN, as indicated by
2365 WHERE. OLD is the original stack layout, and NEW is the desired
2366 form. OLD is updated to reflect the code emitted, i.e., it will be
2367 the same as NEW upon return.
2369 This function will not preserve block_end[]. But that information
2370 is no longer needed once this has executed. */
2373 change_stack (rtx insn
, stack old
, stack new_stack
, enum emit_where where
)
2379 /* Stack adjustments for the first insn in a block update the
2380 current_block's stack_in instead of inserting insns directly.
2381 compensate_edges will add the necessary code later. */
2384 && where
== EMIT_BEFORE
)
2386 BLOCK_INFO (current_block
)->stack_in
= *new_stack
;
2387 starting_stack_p
= false;
2392 /* We will be inserting new insns "backwards". If we are to insert
2393 after INSN, find the next insn, and insert before it. */
2395 if (where
== EMIT_AFTER
)
2397 if (current_block
&& BB_END (current_block
) == insn
)
2399 insn
= NEXT_INSN (insn
);
2402 /* Initialize partially dead variables. */
2403 for (i
= FIRST_STACK_REG
; i
< LAST_STACK_REG
+ 1; i
++)
2404 if (TEST_HARD_REG_BIT (new_stack
->reg_set
, i
)
2405 && !TEST_HARD_REG_BIT (old
->reg_set
, i
))
2407 old
->reg
[++old
->top
] = i
;
2408 SET_HARD_REG_BIT (old
->reg_set
, i
);
2409 emit_insn_before (gen_rtx_SET (VOIDmode
,
2410 FP_MODE_REG (i
, SFmode
), not_a_num
), insn
);
2413 /* Pop any registers that are not needed in the new block. */
2415 /* If the destination block's stack already has a specified layout
2416 and contains two or more registers, use a more intelligent algorithm
2417 to pop registers that minimizes the number number of fxchs below. */
2418 if (new_stack
->top
> 0)
2420 bool slots
[REG_STACK_SIZE
];
2421 int pops
[REG_STACK_SIZE
];
2422 int next
, dest
, topsrc
;
2424 /* First pass to determine the free slots. */
2425 for (reg
= 0; reg
<= new_stack
->top
; reg
++)
2426 slots
[reg
] = TEST_HARD_REG_BIT (new_stack
->reg_set
, old
->reg
[reg
]);
2428 /* Second pass to allocate preferred slots. */
2430 for (reg
= old
->top
; reg
> new_stack
->top
; reg
--)
2431 if (TEST_HARD_REG_BIT (new_stack
->reg_set
, old
->reg
[reg
]))
2434 for (next
= 0; next
<= new_stack
->top
; next
++)
2435 if (!slots
[next
] && new_stack
->reg
[next
] == old
->reg
[reg
])
2437 /* If this is a preference for the new top of stack, record
2438 the fact by remembering it's old->reg in topsrc. */
2439 if (next
== new_stack
->top
)
2450 /* Intentionally, avoid placing the top of stack in it's correct
2451 location, if we still need to permute the stack below and we
2452 can usefully place it somewhere else. This is the case if any
2453 slot is still unallocated, in which case we should place the
2454 top of stack there. */
2456 for (reg
= 0; reg
< new_stack
->top
; reg
++)
2460 slots
[new_stack
->top
] = false;
2465 /* Third pass allocates remaining slots and emits pop insns. */
2466 next
= new_stack
->top
;
2467 for (reg
= old
->top
; reg
> new_stack
->top
; reg
--)
2472 /* Find next free slot. */
2477 emit_pop_insn (insn
, old
, FP_MODE_REG (old
->reg
[dest
], DFmode
),
2483 /* The following loop attempts to maximize the number of times we
2484 pop the top of the stack, as this permits the use of the faster
2485 ffreep instruction on platforms that support it. */
2489 for (reg
= 0; reg
<= old
->top
; reg
++)
2490 if (TEST_HARD_REG_BIT (new_stack
->reg_set
, old
->reg
[reg
]))
2494 while (old
->top
>= live
)
2495 if (TEST_HARD_REG_BIT (new_stack
->reg_set
, old
->reg
[old
->top
]))
2497 while (TEST_HARD_REG_BIT (new_stack
->reg_set
, old
->reg
[next
]))
2499 emit_pop_insn (insn
, old
, FP_MODE_REG (old
->reg
[next
], DFmode
),
2503 emit_pop_insn (insn
, old
, FP_MODE_REG (old
->reg
[old
->top
], DFmode
),
2507 if (new_stack
->top
== -2)
2509 /* If the new block has never been processed, then it can inherit
2510 the old stack order. */
2512 new_stack
->top
= old
->top
;
2513 memcpy (new_stack
->reg
, old
->reg
, sizeof (new_stack
->reg
));
2517 /* This block has been entered before, and we must match the
2518 previously selected stack order. */
2520 /* By now, the only difference should be the order of the stack,
2521 not their depth or liveliness. */
2523 gcc_assert (hard_reg_set_equal_p (old
->reg_set
, new_stack
->reg_set
));
2524 gcc_assert (old
->top
== new_stack
->top
);
2526 /* If the stack is not empty (new_stack->top != -1), loop here emitting
2527 swaps until the stack is correct.
2529 The worst case number of swaps emitted is N + 2, where N is the
2530 depth of the stack. In some cases, the reg at the top of
2531 stack may be correct, but swapped anyway in order to fix
2532 other regs. But since we never swap any other reg away from
2533 its correct slot, this algorithm will converge. */
2535 if (new_stack
->top
!= -1)
2538 /* Swap the reg at top of stack into the position it is
2539 supposed to be in, until the correct top of stack appears. */
2541 while (old
->reg
[old
->top
] != new_stack
->reg
[new_stack
->top
])
2543 for (reg
= new_stack
->top
; reg
>= 0; reg
--)
2544 if (new_stack
->reg
[reg
] == old
->reg
[old
->top
])
2547 gcc_assert (reg
!= -1);
2549 emit_swap_insn (insn
, old
,
2550 FP_MODE_REG (old
->reg
[reg
], DFmode
));
2553 /* See if any regs remain incorrect. If so, bring an
2554 incorrect reg to the top of stack, and let the while loop
2557 for (reg
= new_stack
->top
; reg
>= 0; reg
--)
2558 if (new_stack
->reg
[reg
] != old
->reg
[reg
])
2560 emit_swap_insn (insn
, old
,
2561 FP_MODE_REG (old
->reg
[reg
], DFmode
));
2566 /* At this point there must be no differences. */
2568 for (reg
= old
->top
; reg
>= 0; reg
--)
2569 gcc_assert (old
->reg
[reg
] == new_stack
->reg
[reg
]);
2573 BB_END (current_block
) = PREV_INSN (insn
);
2576 /* Print stack configuration. */
2579 print_stack (FILE *file
, stack s
)
2585 fprintf (file
, "uninitialized\n");
2586 else if (s
->top
== -1)
2587 fprintf (file
, "empty\n");
2592 for (i
= 0; i
<= s
->top
; ++i
)
2593 fprintf (file
, "%d ", s
->reg
[i
]);
2594 fputs ("]\n", file
);
2598 /* This function was doing life analysis. We now let the regular live
2599 code do it's job, so we only need to check some extra invariants
2600 that reg-stack expects. Primary among these being that all registers
2601 are initialized before use.
2603 The function returns true when code was emitted to CFG edges and
2604 commit_edge_insertions needs to be called. */
2607 convert_regs_entry (void)
2613 /* Load something into each stack register live at function entry.
2614 Such live registers can be caused by uninitialized variables or
2615 functions not returning values on all paths. In order to keep
2616 the push/pop code happy, and to not scrog the register stack, we
2617 must put something in these registers. Use a QNaN.
2619 Note that we are inserting converted code here. This code is
2620 never seen by the convert_regs pass. */
2622 FOR_EACH_EDGE (e
, ei
, ENTRY_BLOCK_PTR
->succs
)
2624 basic_block block
= e
->dest
;
2625 block_info bi
= BLOCK_INFO (block
);
2628 for (reg
= LAST_STACK_REG
; reg
>= FIRST_STACK_REG
; --reg
)
2629 if (TEST_HARD_REG_BIT (bi
->stack_in
.reg_set
, reg
))
2633 bi
->stack_in
.reg
[++top
] = reg
;
2635 init
= gen_rtx_SET (VOIDmode
,
2636 FP_MODE_REG (FIRST_STACK_REG
, SFmode
),
2638 insert_insn_on_edge (init
, e
);
2642 bi
->stack_in
.top
= top
;
2648 /* Construct the desired stack for function exit. This will either
2649 be `empty', or the function return value at top-of-stack. */
2652 convert_regs_exit (void)
2654 int value_reg_low
, value_reg_high
;
2658 retvalue
= stack_result (current_function_decl
);
2659 value_reg_low
= value_reg_high
= -1;
2662 value_reg_low
= REGNO (retvalue
);
2663 value_reg_high
= END_HARD_REGNO (retvalue
) - 1;
2666 output_stack
= &BLOCK_INFO (EXIT_BLOCK_PTR
)->stack_in
;
2667 if (value_reg_low
== -1)
2668 output_stack
->top
= -1;
2673 output_stack
->top
= value_reg_high
- value_reg_low
;
2674 for (reg
= value_reg_low
; reg
<= value_reg_high
; ++reg
)
2676 output_stack
->reg
[value_reg_high
- reg
] = reg
;
2677 SET_HARD_REG_BIT (output_stack
->reg_set
, reg
);
2682 /* Copy the stack info from the end of edge E's source block to the
2683 start of E's destination block. */
2686 propagate_stack (edge e
)
2688 stack src_stack
= &BLOCK_INFO (e
->src
)->stack_out
;
2689 stack dest_stack
= &BLOCK_INFO (e
->dest
)->stack_in
;
2692 /* Preserve the order of the original stack, but check whether
2693 any pops are needed. */
2694 dest_stack
->top
= -1;
2695 for (reg
= 0; reg
<= src_stack
->top
; ++reg
)
2696 if (TEST_HARD_REG_BIT (dest_stack
->reg_set
, src_stack
->reg
[reg
]))
2697 dest_stack
->reg
[++dest_stack
->top
] = src_stack
->reg
[reg
];
2699 /* Push in any partially dead values. */
2700 for (reg
= FIRST_STACK_REG
; reg
< LAST_STACK_REG
+ 1; reg
++)
2701 if (TEST_HARD_REG_BIT (dest_stack
->reg_set
, reg
)
2702 && !TEST_HARD_REG_BIT (src_stack
->reg_set
, reg
))
2703 dest_stack
->reg
[++dest_stack
->top
] = reg
;
2707 /* Adjust the stack of edge E's source block on exit to match the stack
2708 of it's target block upon input. The stack layouts of both blocks
2709 should have been defined by now. */
2712 compensate_edge (edge e
)
2714 basic_block source
= e
->src
, target
= e
->dest
;
2715 stack target_stack
= &BLOCK_INFO (target
)->stack_in
;
2716 stack source_stack
= &BLOCK_INFO (source
)->stack_out
;
2717 struct stack_def regstack
;
2721 fprintf (dump_file
, "Edge %d->%d: ", source
->index
, target
->index
);
2723 gcc_assert (target_stack
->top
!= -2);
2725 /* Check whether stacks are identical. */
2726 if (target_stack
->top
== source_stack
->top
)
2728 for (reg
= target_stack
->top
; reg
>= 0; --reg
)
2729 if (target_stack
->reg
[reg
] != source_stack
->reg
[reg
])
2735 fprintf (dump_file
, "no changes needed\n");
2742 fprintf (dump_file
, "correcting stack to ");
2743 print_stack (dump_file
, target_stack
);
2746 /* Abnormal calls may appear to have values live in st(0), but the
2747 abnormal return path will not have actually loaded the values. */
2748 if (e
->flags
& EDGE_ABNORMAL_CALL
)
2750 /* Assert that the lifetimes are as we expect -- one value
2751 live at st(0) on the end of the source block, and no
2752 values live at the beginning of the destination block.
2753 For complex return values, we may have st(1) live as well. */
2754 gcc_assert (source_stack
->top
== 0 || source_stack
->top
== 1);
2755 gcc_assert (target_stack
->top
== -1);
2759 /* Handle non-call EH edges specially. The normal return path have
2760 values in registers. These will be popped en masse by the unwind
2762 if (e
->flags
& EDGE_EH
)
2764 gcc_assert (target_stack
->top
== -1);
2768 /* We don't support abnormal edges. Global takes care to
2769 avoid any live register across them, so we should never
2770 have to insert instructions on such edges. */
2771 gcc_assert (! (e
->flags
& EDGE_ABNORMAL
));
2773 /* Make a copy of source_stack as change_stack is destructive. */
2774 regstack
= *source_stack
;
2776 /* It is better to output directly to the end of the block
2777 instead of to the edge, because emit_swap can do minimal
2778 insn scheduling. We can do this when there is only one
2779 edge out, and it is not abnormal. */
2780 if (EDGE_COUNT (source
->succs
) == 1)
2782 current_block
= source
;
2783 change_stack (BB_END (source
), ®stack
, target_stack
,
2784 (JUMP_P (BB_END (source
)) ? EMIT_BEFORE
: EMIT_AFTER
));
2790 current_block
= NULL
;
2793 /* ??? change_stack needs some point to emit insns after. */
2794 after
= emit_note (NOTE_INSN_DELETED
);
2796 change_stack (after
, ®stack
, target_stack
, EMIT_BEFORE
);
2801 insert_insn_on_edge (seq
, e
);
2807 /* Traverse all non-entry edges in the CFG, and emit the necessary
2808 edge compensation code to change the stack from stack_out of the
2809 source block to the stack_in of the destination block. */
2812 compensate_edges (void)
2814 bool inserted
= false;
2817 starting_stack_p
= false;
2820 if (bb
!= ENTRY_BLOCK_PTR
)
2825 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2826 inserted
|= compensate_edge (e
);
2831 /* Select the better of two edges E1 and E2 to use to determine the
2832 stack layout for their shared destination basic block. This is
2833 typically the more frequently executed. The edge E1 may be NULL
2834 (in which case E2 is returned), but E2 is always non-NULL. */
2837 better_edge (edge e1
, edge e2
)
2842 if (EDGE_FREQUENCY (e1
) > EDGE_FREQUENCY (e2
))
2844 if (EDGE_FREQUENCY (e1
) < EDGE_FREQUENCY (e2
))
2847 if (e1
->count
> e2
->count
)
2849 if (e1
->count
< e2
->count
)
2852 /* Prefer critical edges to minimize inserting compensation code on
2855 if (EDGE_CRITICAL_P (e1
) != EDGE_CRITICAL_P (e2
))
2856 return EDGE_CRITICAL_P (e1
) ? e1
: e2
;
2858 /* Avoid non-deterministic behavior. */
2859 return (e1
->src
->index
< e2
->src
->index
) ? e1
: e2
;
2862 /* Convert stack register references in one block. */
2865 convert_regs_1 (basic_block block
)
2867 struct stack_def regstack
;
2868 block_info bi
= BLOCK_INFO (block
);
2871 bool control_flow_insn_deleted
= false;
2873 any_malformed_asm
= false;
2875 /* Choose an initial stack layout, if one hasn't already been chosen. */
2876 if (bi
->stack_in
.top
== -2)
2878 edge e
, beste
= NULL
;
2881 /* Select the best incoming edge (typically the most frequent) to
2882 use as a template for this basic block. */
2883 FOR_EACH_EDGE (e
, ei
, block
->preds
)
2884 if (BLOCK_INFO (e
->src
)->done
)
2885 beste
= better_edge (beste
, e
);
2888 propagate_stack (beste
);
2891 /* No predecessors. Create an arbitrary input stack. */
2892 bi
->stack_in
.top
= -1;
2893 for (reg
= LAST_STACK_REG
; reg
>= FIRST_STACK_REG
; --reg
)
2894 if (TEST_HARD_REG_BIT (bi
->stack_in
.reg_set
, reg
))
2895 bi
->stack_in
.reg
[++bi
->stack_in
.top
] = reg
;
2901 fprintf (dump_file
, "\nBasic block %d\nInput stack: ", block
->index
);
2902 print_stack (dump_file
, &bi
->stack_in
);
2905 /* Process all insns in this block. Keep track of NEXT so that we
2906 don't process insns emitted while substituting in INSN. */
2907 current_block
= block
;
2908 next
= BB_HEAD (block
);
2909 regstack
= bi
->stack_in
;
2910 starting_stack_p
= true;
2915 next
= NEXT_INSN (insn
);
2917 /* Ensure we have not missed a block boundary. */
2919 if (insn
== BB_END (block
))
2922 /* Don't bother processing unless there is a stack reg
2923 mentioned or if it's a CALL_INSN. */
2924 if (stack_regs_mentioned (insn
)
2929 fprintf (dump_file
, " insn %d input stack: ",
2931 print_stack (dump_file
, ®stack
);
2933 control_flow_insn_deleted
|= subst_stack_regs (insn
, ®stack
);
2934 starting_stack_p
= false;
2941 fprintf (dump_file
, "Expected live registers [");
2942 for (reg
= FIRST_STACK_REG
; reg
<= LAST_STACK_REG
; ++reg
)
2943 if (TEST_HARD_REG_BIT (bi
->out_reg_set
, reg
))
2944 fprintf (dump_file
, " %d", reg
);
2945 fprintf (dump_file
, " ]\nOutput stack: ");
2946 print_stack (dump_file
, ®stack
);
2949 insn
= BB_END (block
);
2951 insn
= PREV_INSN (insn
);
2953 /* If the function is declared to return a value, but it returns one
2954 in only some cases, some registers might come live here. Emit
2955 necessary moves for them. */
2957 for (reg
= FIRST_STACK_REG
; reg
<= LAST_STACK_REG
; ++reg
)
2959 if (TEST_HARD_REG_BIT (bi
->out_reg_set
, reg
)
2960 && ! TEST_HARD_REG_BIT (regstack
.reg_set
, reg
))
2965 fprintf (dump_file
, "Emitting insn initializing reg %d\n", reg
);
2967 set
= gen_rtx_SET (VOIDmode
, FP_MODE_REG (reg
, SFmode
), not_a_num
);
2968 insn
= emit_insn_after (set
, insn
);
2969 control_flow_insn_deleted
|= subst_stack_regs (insn
, ®stack
);
2973 /* Amongst the insns possibly deleted during the substitution process above,
2974 might have been the only trapping insn in the block. We purge the now
2975 possibly dead EH edges here to avoid an ICE from fixup_abnormal_edges,
2976 called at the end of convert_regs. The order in which we process the
2977 blocks ensures that we never delete an already processed edge.
2979 Note that, at this point, the CFG may have been damaged by the emission
2980 of instructions after an abnormal call, which moves the basic block end
2981 (and is the reason why we call fixup_abnormal_edges later). So we must
2982 be sure that the trapping insn has been deleted before trying to purge
2983 dead edges, otherwise we risk purging valid edges.
2985 ??? We are normally supposed not to delete trapping insns, so we pretend
2986 that the insns deleted above don't actually trap. It would have been
2987 better to detect this earlier and avoid creating the EH edge in the first
2988 place, still, but we don't have enough information at that time. */
2990 if (control_flow_insn_deleted
)
2991 purge_dead_edges (block
);
2993 /* Something failed if the stack lives don't match. If we had malformed
2994 asms, we zapped the instruction itself, but that didn't produce the
2995 same pattern of register kills as before. */
2997 gcc_assert (hard_reg_set_equal_p (regstack
.reg_set
, bi
->out_reg_set
)
2998 || any_malformed_asm
);
2999 bi
->stack_out
= regstack
;
3003 /* Convert registers in all blocks reachable from BLOCK. */
3006 convert_regs_2 (basic_block block
)
3008 basic_block
*stack
, *sp
;
3010 /* We process the blocks in a top-down manner, in a way such that one block
3011 is only processed after all its predecessors. The number of predecessors
3012 of every block has already been computed. */
3014 stack
= XNEWVEC (basic_block
, n_basic_blocks
);
3026 /* Processing BLOCK is achieved by convert_regs_1, which may purge
3027 some dead EH outgoing edge after the deletion of the trapping
3028 insn inside the block. Since the number of predecessors of
3029 BLOCK's successors was computed based on the initial edge set,
3030 we check the necessity to process some of these successors
3031 before such an edge deletion may happen. However, there is
3032 a pitfall: if BLOCK is the only predecessor of a successor and
3033 the edge between them happens to be deleted, the successor
3034 becomes unreachable and should not be processed. The problem
3035 is that there is no way to preventively detect this case so we
3036 stack the successor in all cases and hand over the task of
3037 fixing up the discrepancy to convert_regs_1. */
3039 FOR_EACH_EDGE (e
, ei
, block
->succs
)
3040 if (! (e
->flags
& EDGE_DFS_BACK
))
3042 BLOCK_INFO (e
->dest
)->predecessors
--;
3043 if (!BLOCK_INFO (e
->dest
)->predecessors
)
3047 convert_regs_1 (block
);
3049 while (sp
!= stack
);
3054 /* Traverse all basic blocks in a function, converting the register
3055 references in each insn from the "flat" register file that gcc uses,
3056 to the stack-like registers the 387 uses. */
3066 /* Initialize uninitialized registers on function entry. */
3067 inserted
= convert_regs_entry ();
3069 /* Construct the desired stack for function exit. */
3070 convert_regs_exit ();
3071 BLOCK_INFO (EXIT_BLOCK_PTR
)->done
= 1;
3073 /* ??? Future: process inner loops first, and give them arbitrary
3074 initial stacks which emit_swap_insn can modify. This ought to
3075 prevent double fxch that often appears at the head of a loop. */
3077 /* Process all blocks reachable from all entry points. */
3078 FOR_EACH_EDGE (e
, ei
, ENTRY_BLOCK_PTR
->succs
)
3079 convert_regs_2 (e
->dest
);
3081 /* ??? Process all unreachable blocks. Though there's no excuse
3082 for keeping these even when not optimizing. */
3085 block_info bi
= BLOCK_INFO (b
);
3091 inserted
|= compensate_edges ();
3093 clear_aux_for_blocks ();
3095 fixup_abnormal_edges ();
3097 commit_edge_insertions ();
3100 fputc ('\n', dump_file
);
3103 /* Convert register usage from "flat" register file usage to a "stack
3104 register file. FILE is the dump file, if used.
3106 Construct a CFG and run life analysis. Then convert each insn one
3107 by one. Run a last cleanup_cfg pass, if optimizing, to eliminate
3108 code duplication created when the converter inserts pop insns on
3118 /* Clean up previous run. */
3119 if (stack_regs_mentioned_data
!= NULL
)
3120 VEC_free (char, heap
, stack_regs_mentioned_data
);
3122 /* See if there is something to do. Flow analysis is quite
3123 expensive so we might save some compilation time. */
3124 for (i
= FIRST_STACK_REG
; i
<= LAST_STACK_REG
; i
++)
3125 if (df_regs_ever_live_p (i
))
3127 if (i
> LAST_STACK_REG
)
3130 df_note_add_problem ();
3133 mark_dfs_back_edges ();
3135 /* Set up block info for each basic block. */
3136 alloc_aux_for_blocks (sizeof (struct block_info_def
));
3139 block_info bi
= BLOCK_INFO (bb
);
3144 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3145 if (!(e
->flags
& EDGE_DFS_BACK
)
3146 && e
->src
!= ENTRY_BLOCK_PTR
)
3149 /* Set current register status at last instruction `uninitialized'. */
3150 bi
->stack_in
.top
= -2;
3152 /* Copy live_at_end and live_at_start into temporaries. */
3153 for (reg
= FIRST_STACK_REG
; reg
<= LAST_STACK_REG
; reg
++)
3155 if (REGNO_REG_SET_P (DF_LR_OUT (bb
), reg
))
3156 SET_HARD_REG_BIT (bi
->out_reg_set
, reg
);
3157 if (REGNO_REG_SET_P (DF_LR_IN (bb
), reg
))
3158 SET_HARD_REG_BIT (bi
->stack_in
.reg_set
, reg
);
3162 /* Create the replacement registers up front. */
3163 for (i
= FIRST_STACK_REG
; i
<= LAST_STACK_REG
; i
++)
3165 enum machine_mode mode
;
3166 for (mode
= GET_CLASS_NARROWEST_MODE (MODE_FLOAT
);
3168 mode
= GET_MODE_WIDER_MODE (mode
))
3169 FP_MODE_REG (i
, mode
) = gen_rtx_REG (mode
, i
);
3170 for (mode
= GET_CLASS_NARROWEST_MODE (MODE_COMPLEX_FLOAT
);
3172 mode
= GET_MODE_WIDER_MODE (mode
))
3173 FP_MODE_REG (i
, mode
) = gen_rtx_REG (mode
, i
);
3176 ix86_flags_rtx
= gen_rtx_REG (CCmode
, FLAGS_REG
);
3178 /* A QNaN for initializing uninitialized variables.
3180 ??? We can't load from constant memory in PIC mode, because
3181 we're inserting these instructions before the prologue and
3182 the PIC register hasn't been set up. In that case, fall back
3183 on zero, which we can get from `fldz'. */
3185 if ((flag_pic
&& !TARGET_64BIT
)
3186 || ix86_cmodel
== CM_LARGE
|| ix86_cmodel
== CM_LARGE_PIC
)
3187 not_a_num
= CONST0_RTX (SFmode
);
3192 real_nan (&r
, "", 1, SFmode
);
3193 not_a_num
= CONST_DOUBLE_FROM_REAL_VALUE (r
, SFmode
);
3194 not_a_num
= force_const_mem (SFmode
, not_a_num
);
3197 /* Allocate a cache for stack_regs_mentioned. */
3198 max_uid
= get_max_uid ();
3199 stack_regs_mentioned_data
= VEC_alloc (char, heap
, max_uid
+ 1);
3200 memset (VEC_address (char, stack_regs_mentioned_data
),
3201 0, sizeof (char) * (max_uid
+ 1));
3205 free_aux_for_blocks ();
3208 #endif /* STACK_REGS */
3211 gate_handle_stack_regs (void)
3220 struct rtl_opt_pass pass_stack_regs
=
3225 gate_handle_stack_regs
, /* gate */
3229 0, /* static_pass_number */
3230 TV_REG_STACK
, /* tv_id */
3231 0, /* properties_required */
3232 0, /* properties_provided */
3233 0, /* properties_destroyed */
3234 0, /* todo_flags_start */
3235 0 /* todo_flags_finish */
3239 /* Convert register usage from flat register file usage to a stack
3242 rest_of_handle_stack_regs (void)
3246 regstack_completed
= 1;
3251 struct rtl_opt_pass pass_stack_regs_run
=
3257 rest_of_handle_stack_regs
, /* execute */
3260 0, /* static_pass_number */
3261 TV_REG_STACK
, /* tv_id */
3262 0, /* properties_required */
3263 0, /* properties_provided */
3264 0, /* properties_destroyed */
3265 0, /* todo_flags_start */
3266 TODO_df_finish
| TODO_verify_rtl_sharing
|
3268 TODO_ggc_collect
/* todo_flags_finish */