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, 2008, 2010, 2011, 2012
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"
159 #include "rtl-error.h"
161 #include "function.h"
162 #include "insn-config.h"
164 #include "hard-reg-set.h"
167 #include "basic-block.h"
170 #include "tree-pass.h"
173 #include "emit-rtl.h" /* FIXME: Can go away once crtl is moved to rtl.h. */
177 /* We use this array to cache info about insns, because otherwise we
178 spend too much time in stack_regs_mentioned_p.
180 Indexed by insn UIDs. A value of zero is uninitialized, one indicates
181 the insn uses stack registers, two indicates the insn does not use
183 static vec
<char> stack_regs_mentioned_data
;
185 #define REG_STACK_SIZE (LAST_STACK_REG - FIRST_STACK_REG + 1)
187 int regstack_completed
= 0;
189 /* This is the basic stack record. TOP is an index into REG[] such
190 that REG[TOP] is the top of stack. If TOP is -1 the stack is empty.
192 If TOP is -2, REG[] is not yet initialized. Stack initialization
193 consists of placing each live reg in array `reg' and setting `top'
196 REG_SET indicates which registers are live. */
198 typedef struct stack_def
200 int top
; /* index to top stack element */
201 HARD_REG_SET reg_set
; /* set of live registers */
202 unsigned char reg
[REG_STACK_SIZE
];/* register - stack mapping */
205 /* This is used to carry information about basic blocks. It is
206 attached to the AUX field of the standard CFG block. */
208 typedef struct block_info_def
210 struct stack_def stack_in
; /* Input stack configuration. */
211 struct stack_def stack_out
; /* Output stack configuration. */
212 HARD_REG_SET out_reg_set
; /* Stack regs live on output. */
213 int done
; /* True if block already converted. */
214 int predecessors
; /* Number of predecessors that need
218 #define BLOCK_INFO(B) ((block_info) (B)->aux)
220 /* Passed to change_stack to indicate where to emit insns. */
227 /* The block we're currently working on. */
228 static basic_block current_block
;
230 /* In the current_block, whether we're processing the first register
231 stack or call instruction, i.e. the regstack is currently the
232 same as BLOCK_INFO(current_block)->stack_in. */
233 static bool starting_stack_p
;
235 /* This is the register file for all register after conversion. */
237 FP_mode_reg
[LAST_STACK_REG
+1-FIRST_STACK_REG
][(int) MAX_MACHINE_MODE
];
239 #define FP_MODE_REG(regno,mode) \
240 (FP_mode_reg[(regno)-FIRST_STACK_REG][(int) (mode)])
242 /* Used to initialize uninitialized registers. */
243 static rtx not_a_num
;
245 /* Forward declarations */
247 static int stack_regs_mentioned_p (const_rtx pat
);
248 static void pop_stack (stack_ptr
, int);
249 static rtx
*get_true_reg (rtx
*);
251 static int check_asm_stack_operands (rtx
);
252 static void get_asm_operands_in_out (rtx
, int *, int *);
253 static rtx
stack_result (tree
);
254 static void replace_reg (rtx
*, int);
255 static void remove_regno_note (rtx
, enum reg_note
, unsigned int);
256 static int get_hard_regnum (stack_ptr
, rtx
);
257 static rtx
emit_pop_insn (rtx
, stack_ptr
, rtx
, enum emit_where
);
258 static void swap_to_top(rtx
, stack_ptr
, rtx
, rtx
);
259 static bool move_for_stack_reg (rtx
, stack_ptr
, rtx
);
260 static bool move_nan_for_stack_reg (rtx
, stack_ptr
, rtx
);
261 static int swap_rtx_condition_1 (rtx
);
262 static int swap_rtx_condition (rtx
);
263 static void compare_for_stack_reg (rtx
, stack_ptr
, rtx
);
264 static bool subst_stack_regs_pat (rtx
, stack_ptr
, rtx
);
265 static void subst_asm_stack_regs (rtx
, stack_ptr
);
266 static bool subst_stack_regs (rtx
, stack_ptr
);
267 static void change_stack (rtx
, stack_ptr
, stack_ptr
, enum emit_where
);
268 static void print_stack (FILE *, stack_ptr
);
269 static rtx
next_flags_user (rtx
);
271 /* Return nonzero if any stack register is mentioned somewhere within PAT. */
274 stack_regs_mentioned_p (const_rtx pat
)
279 if (STACK_REG_P (pat
))
282 fmt
= GET_RTX_FORMAT (GET_CODE (pat
));
283 for (i
= GET_RTX_LENGTH (GET_CODE (pat
)) - 1; i
>= 0; i
--)
289 for (j
= XVECLEN (pat
, i
) - 1; j
>= 0; j
--)
290 if (stack_regs_mentioned_p (XVECEXP (pat
, i
, j
)))
293 else if (fmt
[i
] == 'e' && stack_regs_mentioned_p (XEXP (pat
, i
)))
300 /* Return nonzero if INSN mentions stacked registers, else return zero. */
303 stack_regs_mentioned (const_rtx insn
)
305 unsigned int uid
, max
;
308 if (! INSN_P (insn
) || !stack_regs_mentioned_data
.exists ())
311 uid
= INSN_UID (insn
);
312 max
= stack_regs_mentioned_data
.length ();
315 /* Allocate some extra size to avoid too many reallocs, but
316 do not grow too quickly. */
317 max
= uid
+ uid
/ 20 + 1;
318 stack_regs_mentioned_data
.safe_grow_cleared (max
);
321 test
= stack_regs_mentioned_data
[uid
];
324 /* This insn has yet to be examined. Do so now. */
325 test
= stack_regs_mentioned_p (PATTERN (insn
)) ? 1 : 2;
326 stack_regs_mentioned_data
[uid
] = test
;
332 static rtx ix86_flags_rtx
;
335 next_flags_user (rtx insn
)
337 /* Search forward looking for the first use of this value.
338 Stop at block boundaries. */
340 while (insn
!= BB_END (current_block
))
342 insn
= NEXT_INSN (insn
);
344 if (INSN_P (insn
) && reg_mentioned_p (ix86_flags_rtx
, PATTERN (insn
)))
353 /* Reorganize the stack into ascending numbers, before this insn. */
356 straighten_stack (rtx insn
, stack_ptr regstack
)
358 struct stack_def temp_stack
;
361 /* If there is only a single register on the stack, then the stack is
362 already in increasing order and no reorganization is needed.
364 Similarly if the stack is empty. */
365 if (regstack
->top
<= 0)
368 COPY_HARD_REG_SET (temp_stack
.reg_set
, regstack
->reg_set
);
370 for (top
= temp_stack
.top
= regstack
->top
; top
>= 0; top
--)
371 temp_stack
.reg
[top
] = FIRST_STACK_REG
+ temp_stack
.top
- top
;
373 change_stack (insn
, regstack
, &temp_stack
, EMIT_BEFORE
);
376 /* Pop a register from the stack. */
379 pop_stack (stack_ptr regstack
, int regno
)
381 int top
= regstack
->top
;
383 CLEAR_HARD_REG_BIT (regstack
->reg_set
, regno
);
385 /* If regno was not at the top of stack then adjust stack. */
386 if (regstack
->reg
[top
] != regno
)
389 for (i
= regstack
->top
; i
>= 0; i
--)
390 if (regstack
->reg
[i
] == regno
)
393 for (j
= i
; j
< top
; j
++)
394 regstack
->reg
[j
] = regstack
->reg
[j
+ 1];
400 /* Return a pointer to the REG expression within PAT. If PAT is not a
401 REG, possible enclosed by a conversion rtx, return the inner part of
402 PAT that stopped the search. */
405 get_true_reg (rtx
*pat
)
408 switch (GET_CODE (*pat
))
411 /* Eliminate FP subregister accesses in favor of the
412 actual FP register in use. */
415 if (STACK_REG_P (subreg
= SUBREG_REG (*pat
)))
417 int regno_off
= subreg_regno_offset (REGNO (subreg
),
421 *pat
= FP_MODE_REG (REGNO (subreg
) + regno_off
,
429 pat
= & XEXP (*pat
, 0);
433 if (XINT (*pat
, 1) == UNSPEC_TRUNC_NOOP
434 || XINT (*pat
, 1) == UNSPEC_LDA
)
435 pat
= & XVECEXP (*pat
, 0, 0);
439 if (!flag_unsafe_math_optimizations
)
441 pat
= & XEXP (*pat
, 0);
449 /* Set if we find any malformed asms in a block. */
450 static bool any_malformed_asm
;
452 /* There are many rules that an asm statement for stack-like regs must
453 follow. Those rules are explained at the top of this file: the rule
454 numbers below refer to that explanation. */
457 check_asm_stack_operands (rtx insn
)
461 int malformed_asm
= 0;
462 rtx body
= PATTERN (insn
);
464 char reg_used_as_output
[FIRST_PSEUDO_REGISTER
];
465 char implicitly_dies
[FIRST_PSEUDO_REGISTER
];
468 rtx
*clobber_reg
= 0;
469 int n_inputs
, n_outputs
;
471 /* Find out what the constraints require. If no constraint
472 alternative matches, this asm is malformed. */
474 constrain_operands (1);
475 alt
= which_alternative
;
477 preprocess_constraints ();
479 get_asm_operands_in_out (body
, &n_outputs
, &n_inputs
);
484 /* Avoid further trouble with this insn. */
485 PATTERN (insn
) = gen_rtx_USE (VOIDmode
, const0_rtx
);
489 /* Strip SUBREGs here to make the following code simpler. */
490 for (i
= 0; i
< recog_data
.n_operands
; i
++)
491 if (GET_CODE (recog_data
.operand
[i
]) == SUBREG
492 && REG_P (SUBREG_REG (recog_data
.operand
[i
])))
493 recog_data
.operand
[i
] = SUBREG_REG (recog_data
.operand
[i
]);
495 /* Set up CLOBBER_REG. */
499 if (GET_CODE (body
) == PARALLEL
)
501 clobber_reg
= XALLOCAVEC (rtx
, XVECLEN (body
, 0));
503 for (i
= 0; i
< XVECLEN (body
, 0); i
++)
504 if (GET_CODE (XVECEXP (body
, 0, i
)) == CLOBBER
)
506 rtx clobber
= XVECEXP (body
, 0, i
);
507 rtx reg
= XEXP (clobber
, 0);
509 if (GET_CODE (reg
) == SUBREG
&& REG_P (SUBREG_REG (reg
)))
510 reg
= SUBREG_REG (reg
);
512 if (STACK_REG_P (reg
))
514 clobber_reg
[n_clobbers
] = reg
;
520 /* Enforce rule #4: Output operands must specifically indicate which
521 reg an output appears in after an asm. "=f" is not allowed: the
522 operand constraints must select a class with a single reg.
524 Also enforce rule #5: Output operands must start at the top of
525 the reg-stack: output operands may not "skip" a reg. */
527 memset (reg_used_as_output
, 0, sizeof (reg_used_as_output
));
528 for (i
= 0; i
< n_outputs
; i
++)
529 if (STACK_REG_P (recog_data
.operand
[i
]))
531 if (reg_class_size
[(int) recog_op_alt
[i
][alt
].cl
] != 1)
533 error_for_asm (insn
, "output constraint %d must specify a single register", i
);
540 for (j
= 0; j
< n_clobbers
; j
++)
541 if (REGNO (recog_data
.operand
[i
]) == REGNO (clobber_reg
[j
]))
543 error_for_asm (insn
, "output constraint %d cannot be specified together with \"%s\" clobber",
544 i
, reg_names
[REGNO (clobber_reg
[j
])]);
549 reg_used_as_output
[REGNO (recog_data
.operand
[i
])] = 1;
554 /* Search for first non-popped reg. */
555 for (i
= FIRST_STACK_REG
; i
< LAST_STACK_REG
+ 1; i
++)
556 if (! reg_used_as_output
[i
])
559 /* If there are any other popped regs, that's an error. */
560 for (; i
< LAST_STACK_REG
+ 1; i
++)
561 if (reg_used_as_output
[i
])
564 if (i
!= LAST_STACK_REG
+ 1)
566 error_for_asm (insn
, "output regs must be grouped at top of stack");
570 /* Enforce rule #2: All implicitly popped input regs must be closer
571 to the top of the reg-stack than any input that is not implicitly
574 memset (implicitly_dies
, 0, sizeof (implicitly_dies
));
575 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
576 if (STACK_REG_P (recog_data
.operand
[i
]))
578 /* An input reg is implicitly popped if it is tied to an
579 output, or if there is a CLOBBER for it. */
582 for (j
= 0; j
< n_clobbers
; j
++)
583 if (operands_match_p (clobber_reg
[j
], recog_data
.operand
[i
]))
586 if (j
< n_clobbers
|| recog_op_alt
[i
][alt
].matches
>= 0)
587 implicitly_dies
[REGNO (recog_data
.operand
[i
])] = 1;
590 /* Search for first non-popped reg. */
591 for (i
= FIRST_STACK_REG
; i
< LAST_STACK_REG
+ 1; i
++)
592 if (! implicitly_dies
[i
])
595 /* If there are any other popped regs, that's an error. */
596 for (; i
< LAST_STACK_REG
+ 1; i
++)
597 if (implicitly_dies
[i
])
600 if (i
!= LAST_STACK_REG
+ 1)
603 "implicitly popped regs must be grouped at top of stack");
607 /* Enforce rule #3: If any input operand uses the "f" constraint, all
608 output constraints must use the "&" earlyclobber.
610 ??? Detect this more deterministically by having constrain_asm_operands
611 record any earlyclobber. */
613 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
614 if (recog_op_alt
[i
][alt
].matches
== -1)
618 for (j
= 0; j
< n_outputs
; j
++)
619 if (operands_match_p (recog_data
.operand
[j
], recog_data
.operand
[i
]))
622 "output operand %d must use %<&%> constraint", j
);
629 /* Avoid further trouble with this insn. */
630 PATTERN (insn
) = gen_rtx_USE (VOIDmode
, const0_rtx
);
631 any_malformed_asm
= true;
638 /* Calculate the number of inputs and outputs in BODY, an
639 asm_operands. N_OPERANDS is the total number of operands, and
640 N_INPUTS and N_OUTPUTS are pointers to ints into which the results are
644 get_asm_operands_in_out (rtx body
, int *pout
, int *pin
)
646 rtx asmop
= extract_asm_operands (body
);
648 *pin
= ASM_OPERANDS_INPUT_LENGTH (asmop
);
649 *pout
= (recog_data
.n_operands
650 - ASM_OPERANDS_INPUT_LENGTH (asmop
)
651 - ASM_OPERANDS_LABEL_LENGTH (asmop
));
654 /* If current function returns its result in an fp stack register,
655 return the REG. Otherwise, return 0. */
658 stack_result (tree decl
)
662 /* If the value is supposed to be returned in memory, then clearly
663 it is not returned in a stack register. */
664 if (aggregate_value_p (DECL_RESULT (decl
), decl
))
667 result
= DECL_RTL_IF_SET (DECL_RESULT (decl
));
669 result
= targetm
.calls
.function_value (TREE_TYPE (DECL_RESULT (decl
)),
672 return result
!= 0 && STACK_REG_P (result
) ? result
: 0;
677 * This section deals with stack register substitution, and forms the second
681 /* Replace REG, which is a pointer to a stack reg RTX, with an RTX for
682 the desired hard REGNO. */
685 replace_reg (rtx
*reg
, int regno
)
687 gcc_assert (IN_RANGE (regno
, FIRST_STACK_REG
, LAST_STACK_REG
));
688 gcc_assert (STACK_REG_P (*reg
));
690 gcc_assert (SCALAR_FLOAT_MODE_P (GET_MODE (*reg
))
691 || GET_MODE_CLASS (GET_MODE (*reg
)) == MODE_COMPLEX_FLOAT
);
693 *reg
= FP_MODE_REG (regno
, GET_MODE (*reg
));
696 /* Remove a note of type NOTE, which must be found, for register
697 number REGNO from INSN. Remove only one such note. */
700 remove_regno_note (rtx insn
, enum reg_note note
, unsigned int regno
)
702 rtx
*note_link
, this_rtx
;
704 note_link
= ®_NOTES (insn
);
705 for (this_rtx
= *note_link
; this_rtx
; this_rtx
= XEXP (this_rtx
, 1))
706 if (REG_NOTE_KIND (this_rtx
) == note
707 && REG_P (XEXP (this_rtx
, 0)) && REGNO (XEXP (this_rtx
, 0)) == regno
)
709 *note_link
= XEXP (this_rtx
, 1);
713 note_link
= &XEXP (this_rtx
, 1);
718 /* Find the hard register number of virtual register REG in REGSTACK.
719 The hard register number is relative to the top of the stack. -1 is
720 returned if the register is not found. */
723 get_hard_regnum (stack_ptr regstack
, rtx reg
)
727 gcc_assert (STACK_REG_P (reg
));
729 for (i
= regstack
->top
; i
>= 0; i
--)
730 if (regstack
->reg
[i
] == REGNO (reg
))
733 return i
>= 0 ? (FIRST_STACK_REG
+ regstack
->top
- i
) : -1;
736 /* Emit an insn to pop virtual register REG before or after INSN.
737 REGSTACK is the stack state after INSN and is updated to reflect this
738 pop. WHEN is either emit_insn_before or emit_insn_after. A pop insn
739 is represented as a SET whose destination is the register to be popped
740 and source is the top of stack. A death note for the top of stack
741 cases the movdf pattern to pop. */
744 emit_pop_insn (rtx insn
, stack_ptr regstack
, rtx reg
, enum emit_where where
)
746 rtx pop_insn
, pop_rtx
;
749 /* For complex types take care to pop both halves. These may survive in
750 CLOBBER and USE expressions. */
751 if (COMPLEX_MODE_P (GET_MODE (reg
)))
753 rtx reg1
= FP_MODE_REG (REGNO (reg
), DFmode
);
754 rtx reg2
= FP_MODE_REG (REGNO (reg
) + 1, DFmode
);
757 if (get_hard_regnum (regstack
, reg1
) >= 0)
758 pop_insn
= emit_pop_insn (insn
, regstack
, reg1
, where
);
759 if (get_hard_regnum (regstack
, reg2
) >= 0)
760 pop_insn
= emit_pop_insn (insn
, regstack
, reg2
, where
);
761 gcc_assert (pop_insn
);
765 hard_regno
= get_hard_regnum (regstack
, reg
);
767 gcc_assert (hard_regno
>= FIRST_STACK_REG
);
769 pop_rtx
= gen_rtx_SET (VOIDmode
, FP_MODE_REG (hard_regno
, DFmode
),
770 FP_MODE_REG (FIRST_STACK_REG
, DFmode
));
772 if (where
== EMIT_AFTER
)
773 pop_insn
= emit_insn_after (pop_rtx
, insn
);
775 pop_insn
= emit_insn_before (pop_rtx
, insn
);
777 add_reg_note (pop_insn
, REG_DEAD
, FP_MODE_REG (FIRST_STACK_REG
, DFmode
));
779 regstack
->reg
[regstack
->top
- (hard_regno
- FIRST_STACK_REG
)]
780 = regstack
->reg
[regstack
->top
];
782 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (reg
));
787 /* Emit an insn before or after INSN to swap virtual register REG with
788 the top of stack. REGSTACK is the stack state before the swap, and
789 is updated to reflect the swap. A swap insn is represented as a
790 PARALLEL of two patterns: each pattern moves one reg to the other.
792 If REG is already at the top of the stack, no insn is emitted. */
795 emit_swap_insn (rtx insn
, stack_ptr regstack
, rtx reg
)
799 int tmp
, other_reg
; /* swap regno temps */
800 rtx i1
; /* the stack-reg insn prior to INSN */
801 rtx i1set
= NULL_RTX
; /* the SET rtx within I1 */
803 hard_regno
= get_hard_regnum (regstack
, reg
);
805 if (hard_regno
== FIRST_STACK_REG
)
807 if (hard_regno
== -1)
809 /* Something failed if the register wasn't on the stack. If we had
810 malformed asms, we zapped the instruction itself, but that didn't
811 produce the same pattern of register sets as before. To prevent
812 further failure, adjust REGSTACK to include REG at TOP. */
813 gcc_assert (any_malformed_asm
);
814 regstack
->reg
[++regstack
->top
] = REGNO (reg
);
817 gcc_assert (hard_regno
>= FIRST_STACK_REG
);
819 other_reg
= regstack
->top
- (hard_regno
- FIRST_STACK_REG
);
821 tmp
= regstack
->reg
[other_reg
];
822 regstack
->reg
[other_reg
] = regstack
->reg
[regstack
->top
];
823 regstack
->reg
[regstack
->top
] = tmp
;
825 /* Find the previous insn involving stack regs, but don't pass a
828 if (current_block
&& insn
!= BB_HEAD (current_block
))
830 rtx tmp
= PREV_INSN (insn
);
831 rtx limit
= PREV_INSN (BB_HEAD (current_block
));
836 || NOTE_INSN_BASIC_BLOCK_P (tmp
)
837 || (NONJUMP_INSN_P (tmp
)
838 && stack_regs_mentioned (tmp
)))
843 tmp
= PREV_INSN (tmp
);
848 && (i1set
= single_set (i1
)) != NULL_RTX
)
850 rtx i1src
= *get_true_reg (&SET_SRC (i1set
));
851 rtx i1dest
= *get_true_reg (&SET_DEST (i1set
));
853 /* If the previous register stack push was from the reg we are to
854 swap with, omit the swap. */
856 if (REG_P (i1dest
) && REGNO (i1dest
) == FIRST_STACK_REG
858 && REGNO (i1src
) == (unsigned) hard_regno
- 1
859 && find_regno_note (i1
, REG_DEAD
, FIRST_STACK_REG
) == NULL_RTX
)
862 /* If the previous insn wrote to the reg we are to swap with,
865 if (REG_P (i1dest
) && REGNO (i1dest
) == (unsigned) hard_regno
866 && REG_P (i1src
) && REGNO (i1src
) == FIRST_STACK_REG
867 && find_regno_note (i1
, REG_DEAD
, FIRST_STACK_REG
) == NULL_RTX
)
871 /* Avoid emitting the swap if this is the first register stack insn
872 of the current_block. Instead update the current_block's stack_in
873 and let compensate edges take care of this for us. */
874 if (current_block
&& starting_stack_p
)
876 BLOCK_INFO (current_block
)->stack_in
= *regstack
;
877 starting_stack_p
= false;
881 swap_rtx
= gen_swapxf (FP_MODE_REG (hard_regno
, XFmode
),
882 FP_MODE_REG (FIRST_STACK_REG
, XFmode
));
885 emit_insn_after (swap_rtx
, i1
);
886 else if (current_block
)
887 emit_insn_before (swap_rtx
, BB_HEAD (current_block
));
889 emit_insn_before (swap_rtx
, insn
);
892 /* Emit an insns before INSN to swap virtual register SRC1 with
893 the top of stack and virtual register SRC2 with second stack
894 slot. REGSTACK is the stack state before the swaps, and
895 is updated to reflect the swaps. A swap insn is represented as a
896 PARALLEL of two patterns: each pattern moves one reg to the other.
898 If SRC1 and/or SRC2 are already at the right place, no swap insn
902 swap_to_top (rtx insn
, stack_ptr regstack
, rtx src1
, rtx src2
)
904 struct stack_def temp_stack
;
905 int regno
, j
, k
, temp
;
907 temp_stack
= *regstack
;
909 /* Place operand 1 at the top of stack. */
910 regno
= get_hard_regnum (&temp_stack
, src1
);
911 gcc_assert (regno
>= 0);
912 if (regno
!= FIRST_STACK_REG
)
914 k
= temp_stack
.top
- (regno
- FIRST_STACK_REG
);
917 temp
= temp_stack
.reg
[k
];
918 temp_stack
.reg
[k
] = temp_stack
.reg
[j
];
919 temp_stack
.reg
[j
] = temp
;
922 /* Place operand 2 next on the stack. */
923 regno
= get_hard_regnum (&temp_stack
, src2
);
924 gcc_assert (regno
>= 0);
925 if (regno
!= FIRST_STACK_REG
+ 1)
927 k
= temp_stack
.top
- (regno
- FIRST_STACK_REG
);
928 j
= temp_stack
.top
- 1;
930 temp
= temp_stack
.reg
[k
];
931 temp_stack
.reg
[k
] = temp_stack
.reg
[j
];
932 temp_stack
.reg
[j
] = temp
;
935 change_stack (insn
, regstack
, &temp_stack
, EMIT_BEFORE
);
938 /* Handle a move to or from a stack register in PAT, which is in INSN.
939 REGSTACK is the current stack. Return whether a control flow insn
940 was deleted in the process. */
943 move_for_stack_reg (rtx insn
, stack_ptr regstack
, rtx pat
)
945 rtx
*psrc
= get_true_reg (&SET_SRC (pat
));
946 rtx
*pdest
= get_true_reg (&SET_DEST (pat
));
949 bool control_flow_insn_deleted
= false;
951 src
= *psrc
; dest
= *pdest
;
953 if (STACK_REG_P (src
) && STACK_REG_P (dest
))
955 /* Write from one stack reg to another. If SRC dies here, then
956 just change the register mapping and delete the insn. */
958 note
= find_regno_note (insn
, REG_DEAD
, REGNO (src
));
963 /* If this is a no-op move, there must not be a REG_DEAD note. */
964 gcc_assert (REGNO (src
) != REGNO (dest
));
966 for (i
= regstack
->top
; i
>= 0; i
--)
967 if (regstack
->reg
[i
] == REGNO (src
))
970 /* The destination must be dead, or life analysis is borked. */
971 gcc_assert (get_hard_regnum (regstack
, dest
) < FIRST_STACK_REG
);
973 /* If the source is not live, this is yet another case of
974 uninitialized variables. Load up a NaN instead. */
976 return move_nan_for_stack_reg (insn
, regstack
, dest
);
978 /* It is possible that the dest is unused after this insn.
979 If so, just pop the src. */
981 if (find_regno_note (insn
, REG_UNUSED
, REGNO (dest
)))
982 emit_pop_insn (insn
, regstack
, src
, EMIT_AFTER
);
985 regstack
->reg
[i
] = REGNO (dest
);
986 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (dest
));
987 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (src
));
990 control_flow_insn_deleted
|= control_flow_insn_p (insn
);
992 return control_flow_insn_deleted
;
995 /* The source reg does not die. */
997 /* If this appears to be a no-op move, delete it, or else it
998 will confuse the machine description output patterns. But if
999 it is REG_UNUSED, we must pop the reg now, as per-insn processing
1000 for REG_UNUSED will not work for deleted insns. */
1002 if (REGNO (src
) == REGNO (dest
))
1004 if (find_regno_note (insn
, REG_UNUSED
, REGNO (dest
)))
1005 emit_pop_insn (insn
, regstack
, dest
, EMIT_AFTER
);
1007 control_flow_insn_deleted
|= control_flow_insn_p (insn
);
1009 return control_flow_insn_deleted
;
1012 /* The destination ought to be dead. */
1013 gcc_assert (get_hard_regnum (regstack
, dest
) < FIRST_STACK_REG
);
1015 replace_reg (psrc
, get_hard_regnum (regstack
, src
));
1017 regstack
->reg
[++regstack
->top
] = REGNO (dest
);
1018 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (dest
));
1019 replace_reg (pdest
, FIRST_STACK_REG
);
1021 else if (STACK_REG_P (src
))
1023 /* Save from a stack reg to MEM, or possibly integer reg. Since
1024 only top of stack may be saved, emit an exchange first if
1027 emit_swap_insn (insn
, regstack
, src
);
1029 note
= find_regno_note (insn
, REG_DEAD
, REGNO (src
));
1032 replace_reg (&XEXP (note
, 0), FIRST_STACK_REG
);
1034 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (src
));
1036 else if ((GET_MODE (src
) == XFmode
)
1037 && regstack
->top
< REG_STACK_SIZE
- 1)
1039 /* A 387 cannot write an XFmode value to a MEM without
1040 clobbering the source reg. The output code can handle
1041 this by reading back the value from the MEM.
1042 But it is more efficient to use a temp register if one is
1043 available. Push the source value here if the register
1044 stack is not full, and then write the value to memory via
1047 rtx top_stack_reg
= FP_MODE_REG (FIRST_STACK_REG
, GET_MODE (src
));
1049 push_rtx
= gen_movxf (top_stack_reg
, top_stack_reg
);
1050 emit_insn_before (push_rtx
, insn
);
1051 add_reg_note (insn
, REG_DEAD
, top_stack_reg
);
1054 replace_reg (psrc
, FIRST_STACK_REG
);
1058 rtx pat
= PATTERN (insn
);
1060 gcc_assert (STACK_REG_P (dest
));
1062 /* Load from MEM, or possibly integer REG or constant, into the
1063 stack regs. The actual target is always the top of the
1064 stack. The stack mapping is changed to reflect that DEST is
1065 now at top of stack. */
1067 /* The destination ought to be dead. However, there is a
1068 special case with i387 UNSPEC_TAN, where destination is live
1069 (an argument to fptan) but inherent load of 1.0 is modelled
1070 as a load from a constant. */
1071 if (GET_CODE (pat
) == PARALLEL
1072 && XVECLEN (pat
, 0) == 2
1073 && GET_CODE (XVECEXP (pat
, 0, 1)) == SET
1074 && GET_CODE (SET_SRC (XVECEXP (pat
, 0, 1))) == UNSPEC
1075 && XINT (SET_SRC (XVECEXP (pat
, 0, 1)), 1) == UNSPEC_TAN
)
1076 emit_swap_insn (insn
, regstack
, dest
);
1078 gcc_assert (get_hard_regnum (regstack
, dest
) < FIRST_STACK_REG
);
1080 gcc_assert (regstack
->top
< REG_STACK_SIZE
);
1082 regstack
->reg
[++regstack
->top
] = REGNO (dest
);
1083 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (dest
));
1084 replace_reg (pdest
, FIRST_STACK_REG
);
1087 return control_flow_insn_deleted
;
1090 /* A helper function which replaces INSN with a pattern that loads up
1091 a NaN into DEST, then invokes move_for_stack_reg. */
1094 move_nan_for_stack_reg (rtx insn
, stack_ptr regstack
, rtx dest
)
1098 dest
= FP_MODE_REG (REGNO (dest
), SFmode
);
1099 pat
= gen_rtx_SET (VOIDmode
, dest
, not_a_num
);
1100 PATTERN (insn
) = pat
;
1101 INSN_CODE (insn
) = -1;
1103 return move_for_stack_reg (insn
, regstack
, pat
);
1106 /* Swap the condition on a branch, if there is one. Return true if we
1107 found a condition to swap. False if the condition was not used as
1111 swap_rtx_condition_1 (rtx pat
)
1116 if (COMPARISON_P (pat
))
1118 PUT_CODE (pat
, swap_condition (GET_CODE (pat
)));
1123 fmt
= GET_RTX_FORMAT (GET_CODE (pat
));
1124 for (i
= GET_RTX_LENGTH (GET_CODE (pat
)) - 1; i
>= 0; i
--)
1130 for (j
= XVECLEN (pat
, i
) - 1; j
>= 0; j
--)
1131 r
|= swap_rtx_condition_1 (XVECEXP (pat
, i
, j
));
1133 else if (fmt
[i
] == 'e')
1134 r
|= swap_rtx_condition_1 (XEXP (pat
, i
));
1142 swap_rtx_condition (rtx insn
)
1144 rtx pat
= PATTERN (insn
);
1146 /* We're looking for a single set to cc0 or an HImode temporary. */
1148 if (GET_CODE (pat
) == SET
1149 && REG_P (SET_DEST (pat
))
1150 && REGNO (SET_DEST (pat
)) == FLAGS_REG
)
1152 insn
= next_flags_user (insn
);
1153 if (insn
== NULL_RTX
)
1155 pat
= PATTERN (insn
);
1158 /* See if this is, or ends in, a fnstsw. If so, we're not doing anything
1159 with the cc value right now. We may be able to search for one
1162 if (GET_CODE (pat
) == SET
1163 && GET_CODE (SET_SRC (pat
)) == UNSPEC
1164 && XINT (SET_SRC (pat
), 1) == UNSPEC_FNSTSW
)
1166 rtx dest
= SET_DEST (pat
);
1168 /* Search forward looking for the first use of this value.
1169 Stop at block boundaries. */
1170 while (insn
!= BB_END (current_block
))
1172 insn
= NEXT_INSN (insn
);
1173 if (INSN_P (insn
) && reg_mentioned_p (dest
, insn
))
1179 /* We haven't found it. */
1180 if (insn
== BB_END (current_block
))
1183 /* So we've found the insn using this value. If it is anything
1184 other than sahf or the value does not die (meaning we'd have
1185 to search further), then we must give up. */
1186 pat
= PATTERN (insn
);
1187 if (GET_CODE (pat
) != SET
1188 || GET_CODE (SET_SRC (pat
)) != UNSPEC
1189 || XINT (SET_SRC (pat
), 1) != UNSPEC_SAHF
1190 || ! dead_or_set_p (insn
, dest
))
1193 /* Now we are prepared to handle this as a normal cc0 setter. */
1194 insn
= next_flags_user (insn
);
1195 if (insn
== NULL_RTX
)
1197 pat
= PATTERN (insn
);
1200 if (swap_rtx_condition_1 (pat
))
1203 INSN_CODE (insn
) = -1;
1204 if (recog_memoized (insn
) == -1)
1206 /* In case the flags don't die here, recurse to try fix
1207 following user too. */
1208 else if (! dead_or_set_p (insn
, ix86_flags_rtx
))
1210 insn
= next_flags_user (insn
);
1211 if (!insn
|| !swap_rtx_condition (insn
))
1216 swap_rtx_condition_1 (pat
);
1224 /* Handle a comparison. Special care needs to be taken to avoid
1225 causing comparisons that a 387 cannot do correctly, such as EQ.
1227 Also, a pop insn may need to be emitted. The 387 does have an
1228 `fcompp' insn that can pop two regs, but it is sometimes too expensive
1229 to do this - a `fcomp' followed by a `fstpl %st(0)' may be easier to
1233 compare_for_stack_reg (rtx insn
, stack_ptr regstack
, rtx pat_src
)
1236 rtx src1_note
, src2_note
;
1238 src1
= get_true_reg (&XEXP (pat_src
, 0));
1239 src2
= get_true_reg (&XEXP (pat_src
, 1));
1241 /* ??? If fxch turns out to be cheaper than fstp, give priority to
1242 registers that die in this insn - move those to stack top first. */
1243 if ((! STACK_REG_P (*src1
)
1244 || (STACK_REG_P (*src2
)
1245 && get_hard_regnum (regstack
, *src2
) == FIRST_STACK_REG
))
1246 && swap_rtx_condition (insn
))
1249 temp
= XEXP (pat_src
, 0);
1250 XEXP (pat_src
, 0) = XEXP (pat_src
, 1);
1251 XEXP (pat_src
, 1) = temp
;
1253 src1
= get_true_reg (&XEXP (pat_src
, 0));
1254 src2
= get_true_reg (&XEXP (pat_src
, 1));
1256 INSN_CODE (insn
) = -1;
1259 /* We will fix any death note later. */
1261 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1263 if (STACK_REG_P (*src2
))
1264 src2_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src2
));
1266 src2_note
= NULL_RTX
;
1268 emit_swap_insn (insn
, regstack
, *src1
);
1270 replace_reg (src1
, FIRST_STACK_REG
);
1272 if (STACK_REG_P (*src2
))
1273 replace_reg (src2
, get_hard_regnum (regstack
, *src2
));
1277 pop_stack (regstack
, REGNO (XEXP (src1_note
, 0)));
1278 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1281 /* If the second operand dies, handle that. But if the operands are
1282 the same stack register, don't bother, because only one death is
1283 needed, and it was just handled. */
1286 && ! (STACK_REG_P (*src1
) && STACK_REG_P (*src2
)
1287 && REGNO (*src1
) == REGNO (*src2
)))
1289 /* As a special case, two regs may die in this insn if src2 is
1290 next to top of stack and the top of stack also dies. Since
1291 we have already popped src1, "next to top of stack" is really
1292 at top (FIRST_STACK_REG) now. */
1294 if (get_hard_regnum (regstack
, XEXP (src2_note
, 0)) == FIRST_STACK_REG
1297 pop_stack (regstack
, REGNO (XEXP (src2_note
, 0)));
1298 replace_reg (&XEXP (src2_note
, 0), FIRST_STACK_REG
+ 1);
1302 /* The 386 can only represent death of the first operand in
1303 the case handled above. In all other cases, emit a separate
1304 pop and remove the death note from here. */
1306 /* link_cc0_insns (insn); */
1308 remove_regno_note (insn
, REG_DEAD
, REGNO (XEXP (src2_note
, 0)));
1310 emit_pop_insn (insn
, regstack
, XEXP (src2_note
, 0),
1316 /* Substitute new registers in LOC, which is part of a debug insn.
1317 REGSTACK is the current register layout. */
1320 subst_stack_regs_in_debug_insn (rtx
*loc
, void *data
)
1322 stack_ptr regstack
= (stack_ptr
)data
;
1325 if (!STACK_REG_P (*loc
))
1328 hard_regno
= get_hard_regnum (regstack
, *loc
);
1330 /* If we can't find an active register, reset this debug insn. */
1331 if (hard_regno
== -1)
1334 gcc_assert (hard_regno
>= FIRST_STACK_REG
);
1336 replace_reg (loc
, hard_regno
);
1341 /* Substitute hardware stack regs in debug insn INSN, using stack
1342 layout REGSTACK. If we can't find a hardware stack reg for any of
1343 the REGs in it, reset the debug insn. */
1346 subst_all_stack_regs_in_debug_insn (rtx insn
, struct stack_def
*regstack
)
1348 int ret
= for_each_rtx (&INSN_VAR_LOCATION_LOC (insn
),
1349 subst_stack_regs_in_debug_insn
,
1353 INSN_VAR_LOCATION_LOC (insn
) = gen_rtx_UNKNOWN_VAR_LOC ();
1355 gcc_checking_assert (ret
== 0);
1358 /* Substitute new registers in PAT, which is part of INSN. REGSTACK
1359 is the current register layout. Return whether a control flow insn
1360 was deleted in the process. */
1363 subst_stack_regs_pat (rtx insn
, stack_ptr regstack
, rtx pat
)
1366 bool control_flow_insn_deleted
= false;
1368 switch (GET_CODE (pat
))
1371 /* Deaths in USE insns can happen in non optimizing compilation.
1372 Handle them by popping the dying register. */
1373 src
= get_true_reg (&XEXP (pat
, 0));
1374 if (STACK_REG_P (*src
)
1375 && find_regno_note (insn
, REG_DEAD
, REGNO (*src
)))
1377 /* USEs are ignored for liveness information so USEs of dead
1378 register might happen. */
1379 if (TEST_HARD_REG_BIT (regstack
->reg_set
, REGNO (*src
)))
1380 emit_pop_insn (insn
, regstack
, *src
, EMIT_AFTER
);
1381 return control_flow_insn_deleted
;
1383 /* Uninitialized USE might happen for functions returning uninitialized
1384 value. We will properly initialize the USE on the edge to EXIT_BLOCK,
1385 so it is safe to ignore the use here. This is consistent with behavior
1386 of dataflow analyzer that ignores USE too. (This also imply that
1387 forcibly initializing the register to NaN here would lead to ICE later,
1388 since the REG_DEAD notes are not issued.) */
1398 dest
= get_true_reg (&XEXP (pat
, 0));
1399 if (STACK_REG_P (*dest
))
1401 note
= find_reg_note (insn
, REG_DEAD
, *dest
);
1403 if (pat
!= PATTERN (insn
))
1405 /* The fix_truncdi_1 pattern wants to be able to
1406 allocate its own scratch register. It does this by
1407 clobbering an fp reg so that it is assured of an
1408 empty reg-stack register. If the register is live,
1409 kill it now. Remove the DEAD/UNUSED note so we
1410 don't try to kill it later too.
1412 In reality the UNUSED note can be absent in some
1413 complicated cases when the register is reused for
1414 partially set variable. */
1417 emit_pop_insn (insn
, regstack
, *dest
, EMIT_BEFORE
);
1419 note
= find_reg_note (insn
, REG_UNUSED
, *dest
);
1421 remove_note (insn
, note
);
1422 replace_reg (dest
, FIRST_STACK_REG
+ 1);
1426 /* A top-level clobber with no REG_DEAD, and no hard-regnum
1427 indicates an uninitialized value. Because reload removed
1428 all other clobbers, this must be due to a function
1429 returning without a value. Load up a NaN. */
1434 if (COMPLEX_MODE_P (GET_MODE (t
)))
1436 rtx u
= FP_MODE_REG (REGNO (t
) + 1, SFmode
);
1437 if (get_hard_regnum (regstack
, u
) == -1)
1439 rtx pat2
= gen_rtx_CLOBBER (VOIDmode
, u
);
1440 rtx insn2
= emit_insn_before (pat2
, insn
);
1441 control_flow_insn_deleted
1442 |= move_nan_for_stack_reg (insn2
, regstack
, u
);
1445 if (get_hard_regnum (regstack
, t
) == -1)
1446 control_flow_insn_deleted
1447 |= move_nan_for_stack_reg (insn
, regstack
, t
);
1456 rtx
*src1
= (rtx
*) 0, *src2
;
1457 rtx src1_note
, src2_note
;
1460 dest
= get_true_reg (&SET_DEST (pat
));
1461 src
= get_true_reg (&SET_SRC (pat
));
1462 pat_src
= SET_SRC (pat
);
1464 /* See if this is a `movM' pattern, and handle elsewhere if so. */
1465 if (STACK_REG_P (*src
)
1466 || (STACK_REG_P (*dest
)
1467 && (REG_P (*src
) || MEM_P (*src
)
1468 || CONST_DOUBLE_P (*src
))))
1470 control_flow_insn_deleted
|= move_for_stack_reg (insn
, regstack
, pat
);
1474 switch (GET_CODE (pat_src
))
1477 compare_for_stack_reg (insn
, regstack
, pat_src
);
1483 for (count
= hard_regno_nregs
[REGNO (*dest
)][GET_MODE (*dest
)];
1486 regstack
->reg
[++regstack
->top
] = REGNO (*dest
) + count
;
1487 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
) + count
);
1490 replace_reg (dest
, FIRST_STACK_REG
);
1494 /* This is a `tstM2' case. */
1495 gcc_assert (*dest
== cc0_rtx
);
1500 case FLOAT_TRUNCATE
:
1504 /* These insns only operate on the top of the stack. DEST might
1505 be cc0_rtx if we're processing a tstM pattern. Also, it's
1506 possible that the tstM case results in a REG_DEAD note on the
1510 src1
= get_true_reg (&XEXP (pat_src
, 0));
1512 emit_swap_insn (insn
, regstack
, *src1
);
1514 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1516 if (STACK_REG_P (*dest
))
1517 replace_reg (dest
, FIRST_STACK_REG
);
1521 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1523 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (*src1
));
1526 replace_reg (src1
, FIRST_STACK_REG
);
1531 /* On i386, reversed forms of subM3 and divM3 exist for
1532 MODE_FLOAT, so the same code that works for addM3 and mulM3
1536 /* These insns can accept the top of stack as a destination
1537 from a stack reg or mem, or can use the top of stack as a
1538 source and some other stack register (possibly top of stack)
1539 as a destination. */
1541 src1
= get_true_reg (&XEXP (pat_src
, 0));
1542 src2
= get_true_reg (&XEXP (pat_src
, 1));
1544 /* We will fix any death note later. */
1546 if (STACK_REG_P (*src1
))
1547 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1549 src1_note
= NULL_RTX
;
1550 if (STACK_REG_P (*src2
))
1551 src2_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src2
));
1553 src2_note
= NULL_RTX
;
1555 /* If either operand is not a stack register, then the dest
1556 must be top of stack. */
1558 if (! STACK_REG_P (*src1
) || ! STACK_REG_P (*src2
))
1559 emit_swap_insn (insn
, regstack
, *dest
);
1562 /* Both operands are REG. If neither operand is already
1563 at the top of stack, choose to make the one that is the
1564 dest the new top of stack. */
1566 int src1_hard_regnum
, src2_hard_regnum
;
1568 src1_hard_regnum
= get_hard_regnum (regstack
, *src1
);
1569 src2_hard_regnum
= get_hard_regnum (regstack
, *src2
);
1571 /* If the source is not live, this is yet another case of
1572 uninitialized variables. Load up a NaN instead. */
1573 if (src1_hard_regnum
== -1)
1575 rtx pat2
= gen_rtx_CLOBBER (VOIDmode
, *src1
);
1576 rtx insn2
= emit_insn_before (pat2
, insn
);
1577 control_flow_insn_deleted
1578 |= move_nan_for_stack_reg (insn2
, regstack
, *src1
);
1580 if (src2_hard_regnum
== -1)
1582 rtx pat2
= gen_rtx_CLOBBER (VOIDmode
, *src2
);
1583 rtx insn2
= emit_insn_before (pat2
, insn
);
1584 control_flow_insn_deleted
1585 |= move_nan_for_stack_reg (insn2
, regstack
, *src2
);
1588 if (src1_hard_regnum
!= FIRST_STACK_REG
1589 && src2_hard_regnum
!= FIRST_STACK_REG
)
1590 emit_swap_insn (insn
, regstack
, *dest
);
1593 if (STACK_REG_P (*src1
))
1594 replace_reg (src1
, get_hard_regnum (regstack
, *src1
));
1595 if (STACK_REG_P (*src2
))
1596 replace_reg (src2
, get_hard_regnum (regstack
, *src2
));
1600 rtx src1_reg
= XEXP (src1_note
, 0);
1602 /* If the register that dies is at the top of stack, then
1603 the destination is somewhere else - merely substitute it.
1604 But if the reg that dies is not at top of stack, then
1605 move the top of stack to the dead reg, as though we had
1606 done the insn and then a store-with-pop. */
1608 if (REGNO (src1_reg
) == regstack
->reg
[regstack
->top
])
1610 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1611 replace_reg (dest
, get_hard_regnum (regstack
, *dest
));
1615 int regno
= get_hard_regnum (regstack
, src1_reg
);
1617 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1618 replace_reg (dest
, regno
);
1620 regstack
->reg
[regstack
->top
- (regno
- FIRST_STACK_REG
)]
1621 = regstack
->reg
[regstack
->top
];
1624 CLEAR_HARD_REG_BIT (regstack
->reg_set
,
1625 REGNO (XEXP (src1_note
, 0)));
1626 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1631 rtx src2_reg
= XEXP (src2_note
, 0);
1632 if (REGNO (src2_reg
) == regstack
->reg
[regstack
->top
])
1634 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1635 replace_reg (dest
, get_hard_regnum (regstack
, *dest
));
1639 int regno
= get_hard_regnum (regstack
, src2_reg
);
1641 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1642 replace_reg (dest
, regno
);
1644 regstack
->reg
[regstack
->top
- (regno
- FIRST_STACK_REG
)]
1645 = regstack
->reg
[regstack
->top
];
1648 CLEAR_HARD_REG_BIT (regstack
->reg_set
,
1649 REGNO (XEXP (src2_note
, 0)));
1650 replace_reg (&XEXP (src2_note
, 0), FIRST_STACK_REG
);
1655 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1656 replace_reg (dest
, get_hard_regnum (regstack
, *dest
));
1659 /* Keep operand 1 matching with destination. */
1660 if (COMMUTATIVE_ARITH_P (pat_src
)
1661 && REG_P (*src1
) && REG_P (*src2
)
1662 && REGNO (*src1
) != REGNO (*dest
))
1664 int tmp
= REGNO (*src1
);
1665 replace_reg (src1
, REGNO (*src2
));
1666 replace_reg (src2
, tmp
);
1671 switch (XINT (pat_src
, 1))
1676 case UNSPEC_FIST_FLOOR
:
1677 case UNSPEC_FIST_CEIL
:
1679 /* These insns only operate on the top of the stack. */
1681 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1682 emit_swap_insn (insn
, regstack
, *src1
);
1684 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1686 if (STACK_REG_P (*dest
))
1687 replace_reg (dest
, FIRST_STACK_REG
);
1691 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1693 CLEAR_HARD_REG_BIT (regstack
->reg_set
, REGNO (*src1
));
1696 replace_reg (src1
, FIRST_STACK_REG
);
1701 /* This insn only operate on the top of the stack. */
1703 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1704 emit_swap_insn (insn
, regstack
, *src1
);
1706 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1708 replace_reg (src1
, FIRST_STACK_REG
);
1712 remove_regno_note (insn
, REG_DEAD
,
1713 REGNO (XEXP (src1_note
, 0)));
1714 emit_pop_insn (insn
, regstack
, XEXP (src1_note
, 0),
1722 case UNSPEC_FRNDINT
:
1725 case UNSPEC_FRNDINT_FLOOR
:
1726 case UNSPEC_FRNDINT_CEIL
:
1727 case UNSPEC_FRNDINT_TRUNC
:
1728 case UNSPEC_FRNDINT_MASK_PM
:
1730 /* Above insns operate on the top of the stack. */
1732 case UNSPEC_SINCOS_COS
:
1733 case UNSPEC_XTRACT_FRACT
:
1735 /* Above insns operate on the top two stack slots,
1736 first part of one input, double output insn. */
1738 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1740 emit_swap_insn (insn
, regstack
, *src1
);
1742 /* Input should never die, it is replaced with output. */
1743 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1744 gcc_assert (!src1_note
);
1746 if (STACK_REG_P (*dest
))
1747 replace_reg (dest
, FIRST_STACK_REG
);
1749 replace_reg (src1
, FIRST_STACK_REG
);
1752 case UNSPEC_SINCOS_SIN
:
1753 case UNSPEC_XTRACT_EXP
:
1755 /* These insns operate on the top two stack slots,
1756 second part of one input, double output insn. */
1763 /* For UNSPEC_TAN, regstack->top is already increased
1764 by inherent load of constant 1.0. */
1766 /* Output value is generated in the second stack slot.
1767 Move current value from second slot to the top. */
1768 regstack
->reg
[regstack
->top
]
1769 = regstack
->reg
[regstack
->top
- 1];
1771 gcc_assert (STACK_REG_P (*dest
));
1773 regstack
->reg
[regstack
->top
- 1] = REGNO (*dest
);
1774 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1775 replace_reg (dest
, FIRST_STACK_REG
+ 1);
1777 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1779 replace_reg (src1
, FIRST_STACK_REG
);
1784 case UNSPEC_FYL2XP1
:
1785 /* These insns operate on the top two stack slots. */
1787 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1788 src2
= get_true_reg (&XVECEXP (pat_src
, 0, 1));
1790 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1791 src2_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src2
));
1793 swap_to_top (insn
, regstack
, *src1
, *src2
);
1795 replace_reg (src1
, FIRST_STACK_REG
);
1796 replace_reg (src2
, FIRST_STACK_REG
+ 1);
1799 replace_reg (&XEXP (src1_note
, 0), FIRST_STACK_REG
);
1801 replace_reg (&XEXP (src2_note
, 0), FIRST_STACK_REG
+ 1);
1803 /* Pop both input operands from the stack. */
1804 CLEAR_HARD_REG_BIT (regstack
->reg_set
,
1805 regstack
->reg
[regstack
->top
]);
1806 CLEAR_HARD_REG_BIT (regstack
->reg_set
,
1807 regstack
->reg
[regstack
->top
- 1]);
1810 /* Push the result back onto the stack. */
1811 regstack
->reg
[++regstack
->top
] = REGNO (*dest
);
1812 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1813 replace_reg (dest
, FIRST_STACK_REG
);
1816 case UNSPEC_FSCALE_FRACT
:
1817 case UNSPEC_FPREM_F
:
1818 case UNSPEC_FPREM1_F
:
1819 /* These insns operate on the top two stack slots,
1820 first part of double input, double output insn. */
1822 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1823 src2
= get_true_reg (&XVECEXP (pat_src
, 0, 1));
1825 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1826 src2_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src2
));
1828 /* Inputs should never die, they are
1829 replaced with outputs. */
1830 gcc_assert (!src1_note
);
1831 gcc_assert (!src2_note
);
1833 swap_to_top (insn
, regstack
, *src1
, *src2
);
1835 /* Push the result back onto stack. Empty stack slot
1836 will be filled in second part of insn. */
1837 if (STACK_REG_P (*dest
))
1839 regstack
->reg
[regstack
->top
] = REGNO (*dest
);
1840 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1841 replace_reg (dest
, FIRST_STACK_REG
);
1844 replace_reg (src1
, FIRST_STACK_REG
);
1845 replace_reg (src2
, FIRST_STACK_REG
+ 1);
1848 case UNSPEC_FSCALE_EXP
:
1849 case UNSPEC_FPREM_U
:
1850 case UNSPEC_FPREM1_U
:
1851 /* These insns operate on the top two stack slots,
1852 second part of double input, double output insn. */
1854 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1855 src2
= get_true_reg (&XVECEXP (pat_src
, 0, 1));
1857 /* Push the result back onto stack. Fill empty slot from
1858 first part of insn and fix top of stack pointer. */
1859 if (STACK_REG_P (*dest
))
1861 regstack
->reg
[regstack
->top
- 1] = REGNO (*dest
);
1862 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1863 replace_reg (dest
, FIRST_STACK_REG
+ 1);
1866 replace_reg (src1
, FIRST_STACK_REG
);
1867 replace_reg (src2
, FIRST_STACK_REG
+ 1);
1870 case UNSPEC_C2_FLAG
:
1871 /* This insn operates on the top two stack slots,
1872 third part of C2 setting double input insn. */
1874 src1
= get_true_reg (&XVECEXP (pat_src
, 0, 0));
1875 src2
= get_true_reg (&XVECEXP (pat_src
, 0, 1));
1877 replace_reg (src1
, FIRST_STACK_REG
);
1878 replace_reg (src2
, FIRST_STACK_REG
+ 1);
1882 /* (unspec [(unspec [(compare)] UNSPEC_FNSTSW)] UNSPEC_SAHF)
1883 The combination matches the PPRO fcomi instruction. */
1885 pat_src
= XVECEXP (pat_src
, 0, 0);
1886 gcc_assert (GET_CODE (pat_src
) == UNSPEC
);
1887 gcc_assert (XINT (pat_src
, 1) == UNSPEC_FNSTSW
);
1891 /* Combined fcomp+fnstsw generated for doing well with
1892 CSE. When optimizing this would have been broken
1895 pat_src
= XVECEXP (pat_src
, 0, 0);
1896 gcc_assert (GET_CODE (pat_src
) == COMPARE
);
1898 compare_for_stack_reg (insn
, regstack
, pat_src
);
1907 /* This insn requires the top of stack to be the destination. */
1909 src1
= get_true_reg (&XEXP (pat_src
, 1));
1910 src2
= get_true_reg (&XEXP (pat_src
, 2));
1912 src1_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src1
));
1913 src2_note
= find_regno_note (insn
, REG_DEAD
, REGNO (*src2
));
1915 /* If the comparison operator is an FP comparison operator,
1916 it is handled correctly by compare_for_stack_reg () who
1917 will move the destination to the top of stack. But if the
1918 comparison operator is not an FP comparison operator, we
1919 have to handle it here. */
1920 if (get_hard_regnum (regstack
, *dest
) >= FIRST_STACK_REG
1921 && REGNO (*dest
) != regstack
->reg
[regstack
->top
])
1923 /* In case one of operands is the top of stack and the operands
1924 dies, it is safe to make it the destination operand by
1925 reversing the direction of cmove and avoid fxch. */
1926 if ((REGNO (*src1
) == regstack
->reg
[regstack
->top
]
1928 || (REGNO (*src2
) == regstack
->reg
[regstack
->top
]
1931 int idx1
= (get_hard_regnum (regstack
, *src1
)
1933 int idx2
= (get_hard_regnum (regstack
, *src2
)
1936 /* Make reg-stack believe that the operands are already
1937 swapped on the stack */
1938 regstack
->reg
[regstack
->top
- idx1
] = REGNO (*src2
);
1939 regstack
->reg
[regstack
->top
- idx2
] = REGNO (*src1
);
1941 /* Reverse condition to compensate the operand swap.
1942 i386 do have comparison always reversible. */
1943 PUT_CODE (XEXP (pat_src
, 0),
1944 reversed_comparison_code (XEXP (pat_src
, 0), insn
));
1947 emit_swap_insn (insn
, regstack
, *dest
);
1955 src_note
[1] = src1_note
;
1956 src_note
[2] = src2_note
;
1958 if (STACK_REG_P (*src1
))
1959 replace_reg (src1
, get_hard_regnum (regstack
, *src1
));
1960 if (STACK_REG_P (*src2
))
1961 replace_reg (src2
, get_hard_regnum (regstack
, *src2
));
1963 for (i
= 1; i
<= 2; i
++)
1966 int regno
= REGNO (XEXP (src_note
[i
], 0));
1968 /* If the register that dies is not at the top of
1969 stack, then move the top of stack to the dead reg.
1970 Top of stack should never die, as it is the
1972 gcc_assert (regno
!= regstack
->reg
[regstack
->top
]);
1973 remove_regno_note (insn
, REG_DEAD
, regno
);
1974 emit_pop_insn (insn
, regstack
, XEXP (src_note
[i
], 0),
1979 /* Make dest the top of stack. Add dest to regstack if
1981 if (get_hard_regnum (regstack
, *dest
) < FIRST_STACK_REG
)
1982 regstack
->reg
[++regstack
->top
] = REGNO (*dest
);
1983 SET_HARD_REG_BIT (regstack
->reg_set
, REGNO (*dest
));
1984 replace_reg (dest
, FIRST_STACK_REG
);
1997 return control_flow_insn_deleted
;
2000 /* Substitute hard regnums for any stack regs in INSN, which has
2001 N_INPUTS inputs and N_OUTPUTS outputs. REGSTACK is the stack info
2002 before the insn, and is updated with changes made here.
2004 There are several requirements and assumptions about the use of
2005 stack-like regs in asm statements. These rules are enforced by
2006 record_asm_stack_regs; see comments there for details. Any
2007 asm_operands left in the RTL at this point may be assume to meet the
2008 requirements, since record_asm_stack_regs removes any problem asm. */
2011 subst_asm_stack_regs (rtx insn
, stack_ptr regstack
)
2013 rtx body
= PATTERN (insn
);
2016 rtx
*note_reg
; /* Array of note contents */
2017 rtx
**note_loc
; /* Address of REG field of each note */
2018 enum reg_note
*note_kind
; /* The type of each note */
2020 rtx
*clobber_reg
= 0;
2021 rtx
**clobber_loc
= 0;
2023 struct stack_def temp_stack
;
2028 int n_inputs
, n_outputs
;
2030 if (! check_asm_stack_operands (insn
))
2033 /* Find out what the constraints required. If no constraint
2034 alternative matches, that is a compiler bug: we should have caught
2035 such an insn in check_asm_stack_operands. */
2036 extract_insn (insn
);
2037 constrain_operands (1);
2038 alt
= which_alternative
;
2040 preprocess_constraints ();
2042 get_asm_operands_in_out (body
, &n_outputs
, &n_inputs
);
2044 gcc_assert (alt
>= 0);
2046 /* Strip SUBREGs here to make the following code simpler. */
2047 for (i
= 0; i
< recog_data
.n_operands
; i
++)
2048 if (GET_CODE (recog_data
.operand
[i
]) == SUBREG
2049 && REG_P (SUBREG_REG (recog_data
.operand
[i
])))
2051 recog_data
.operand_loc
[i
] = & SUBREG_REG (recog_data
.operand
[i
]);
2052 recog_data
.operand
[i
] = SUBREG_REG (recog_data
.operand
[i
]);
2055 /* Set up NOTE_REG, NOTE_LOC and NOTE_KIND. */
2057 for (i
= 0, note
= REG_NOTES (insn
); note
; note
= XEXP (note
, 1))
2060 note_reg
= XALLOCAVEC (rtx
, i
);
2061 note_loc
= XALLOCAVEC (rtx
*, i
);
2062 note_kind
= XALLOCAVEC (enum reg_note
, i
);
2065 for (note
= REG_NOTES (insn
); note
; note
= XEXP (note
, 1))
2067 rtx reg
= XEXP (note
, 0);
2068 rtx
*loc
= & XEXP (note
, 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
)
2077 && (REG_NOTE_KIND (note
) == REG_DEAD
2078 || REG_NOTE_KIND (note
) == REG_UNUSED
))
2080 note_reg
[n_notes
] = reg
;
2081 note_loc
[n_notes
] = loc
;
2082 note_kind
[n_notes
] = REG_NOTE_KIND (note
);
2087 /* Set up CLOBBER_REG and CLOBBER_LOC. */
2091 if (GET_CODE (body
) == PARALLEL
)
2093 clobber_reg
= XALLOCAVEC (rtx
, XVECLEN (body
, 0));
2094 clobber_loc
= XALLOCAVEC (rtx
*, XVECLEN (body
, 0));
2096 for (i
= 0; i
< XVECLEN (body
, 0); i
++)
2097 if (GET_CODE (XVECEXP (body
, 0, i
)) == CLOBBER
)
2099 rtx clobber
= XVECEXP (body
, 0, i
);
2100 rtx reg
= XEXP (clobber
, 0);
2101 rtx
*loc
= & XEXP (clobber
, 0);
2103 if (GET_CODE (reg
) == SUBREG
&& REG_P (SUBREG_REG (reg
)))
2105 loc
= & SUBREG_REG (reg
);
2106 reg
= SUBREG_REG (reg
);
2109 if (STACK_REG_P (reg
))
2111 clobber_reg
[n_clobbers
] = reg
;
2112 clobber_loc
[n_clobbers
] = loc
;
2118 temp_stack
= *regstack
;
2120 /* Put the input regs into the desired place in TEMP_STACK. */
2122 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
2123 if (STACK_REG_P (recog_data
.operand
[i
])
2124 && reg_class_subset_p (recog_op_alt
[i
][alt
].cl
,
2126 && recog_op_alt
[i
][alt
].cl
!= FLOAT_REGS
)
2128 /* If an operand needs to be in a particular reg in
2129 FLOAT_REGS, the constraint was either 't' or 'u'. Since
2130 these constraints are for single register classes, and
2131 reload guaranteed that operand[i] is already in that class,
2132 we can just use REGNO (recog_data.operand[i]) to know which
2133 actual reg this operand needs to be in. */
2135 int regno
= get_hard_regnum (&temp_stack
, recog_data
.operand
[i
]);
2137 gcc_assert (regno
>= 0);
2139 if ((unsigned int) regno
!= REGNO (recog_data
.operand
[i
]))
2141 /* recog_data.operand[i] is not in the right place. Find
2142 it and swap it with whatever is already in I's place.
2143 K is where recog_data.operand[i] is now. J is where it
2147 k
= temp_stack
.top
- (regno
- FIRST_STACK_REG
);
2149 - (REGNO (recog_data
.operand
[i
]) - FIRST_STACK_REG
));
2151 temp
= temp_stack
.reg
[k
];
2152 temp_stack
.reg
[k
] = temp_stack
.reg
[j
];
2153 temp_stack
.reg
[j
] = temp
;
2157 /* Emit insns before INSN to make sure the reg-stack is in the right
2160 change_stack (insn
, regstack
, &temp_stack
, EMIT_BEFORE
);
2162 /* Make the needed input register substitutions. Do death notes and
2163 clobbers too, because these are for inputs, not outputs. */
2165 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
2166 if (STACK_REG_P (recog_data
.operand
[i
]))
2168 int regnum
= get_hard_regnum (regstack
, recog_data
.operand
[i
]);
2170 gcc_assert (regnum
>= 0);
2172 replace_reg (recog_data
.operand_loc
[i
], regnum
);
2175 for (i
= 0; i
< n_notes
; i
++)
2176 if (note_kind
[i
] == REG_DEAD
)
2178 int regnum
= get_hard_regnum (regstack
, note_reg
[i
]);
2180 gcc_assert (regnum
>= 0);
2182 replace_reg (note_loc
[i
], regnum
);
2185 for (i
= 0; i
< n_clobbers
; i
++)
2187 /* It's OK for a CLOBBER to reference a reg that is not live.
2188 Don't try to replace it in that case. */
2189 int regnum
= get_hard_regnum (regstack
, clobber_reg
[i
]);
2193 /* Sigh - clobbers always have QImode. But replace_reg knows
2194 that these regs can't be MODE_INT and will assert. Just put
2195 the right reg there without calling replace_reg. */
2197 *clobber_loc
[i
] = FP_MODE_REG (regnum
, DFmode
);
2201 /* Now remove from REGSTACK any inputs that the asm implicitly popped. */
2203 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
2204 if (STACK_REG_P (recog_data
.operand
[i
]))
2206 /* An input reg is implicitly popped if it is tied to an
2207 output, or if there is a CLOBBER for it. */
2210 for (j
= 0; j
< n_clobbers
; j
++)
2211 if (operands_match_p (clobber_reg
[j
], recog_data
.operand
[i
]))
2214 if (j
< n_clobbers
|| recog_op_alt
[i
][alt
].matches
>= 0)
2216 /* recog_data.operand[i] might not be at the top of stack.
2217 But that's OK, because all we need to do is pop the
2218 right number of regs off of the top of the reg-stack.
2219 record_asm_stack_regs guaranteed that all implicitly
2220 popped regs were grouped at the top of the reg-stack. */
2222 CLEAR_HARD_REG_BIT (regstack
->reg_set
,
2223 regstack
->reg
[regstack
->top
]);
2228 /* Now add to REGSTACK any outputs that the asm implicitly pushed.
2229 Note that there isn't any need to substitute register numbers.
2230 ??? Explain why this is true. */
2232 for (i
= LAST_STACK_REG
; i
>= FIRST_STACK_REG
; i
--)
2234 /* See if there is an output for this hard reg. */
2237 for (j
= 0; j
< n_outputs
; j
++)
2238 if (STACK_REG_P (recog_data
.operand
[j
])
2239 && REGNO (recog_data
.operand
[j
]) == (unsigned) i
)
2241 regstack
->reg
[++regstack
->top
] = i
;
2242 SET_HARD_REG_BIT (regstack
->reg_set
, i
);
2247 /* Now emit a pop insn for any REG_UNUSED output, or any REG_DEAD
2248 input that the asm didn't implicitly pop. If the asm didn't
2249 implicitly pop an input reg, that reg will still be live.
2251 Note that we can't use find_regno_note here: the register numbers
2252 in the death notes have already been substituted. */
2254 for (i
= 0; i
< n_outputs
; 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_UNUSED
)
2263 insn
= emit_pop_insn (insn
, regstack
, recog_data
.operand
[i
],
2269 for (i
= n_outputs
; i
< n_outputs
+ n_inputs
; i
++)
2270 if (STACK_REG_P (recog_data
.operand
[i
]))
2274 for (j
= 0; j
< n_notes
; j
++)
2275 if (REGNO (recog_data
.operand
[i
]) == REGNO (note_reg
[j
])
2276 && note_kind
[j
] == REG_DEAD
2277 && TEST_HARD_REG_BIT (regstack
->reg_set
,
2278 REGNO (recog_data
.operand
[i
])))
2280 insn
= emit_pop_insn (insn
, regstack
, recog_data
.operand
[i
],
2287 /* Substitute stack hard reg numbers for stack virtual registers in
2288 INSN. Non-stack register numbers are not changed. REGSTACK is the
2289 current stack content. Insns may be emitted as needed to arrange the
2290 stack for the 387 based on the contents of the insn. Return whether
2291 a control flow insn was deleted in the process. */
2294 subst_stack_regs (rtx insn
, stack_ptr regstack
)
2296 rtx
*note_link
, note
;
2297 bool control_flow_insn_deleted
= false;
2302 int top
= regstack
->top
;
2304 /* If there are any floating point parameters to be passed in
2305 registers for this call, make sure they are in the right
2310 straighten_stack (insn
, regstack
);
2312 /* Now mark the arguments as dead after the call. */
2314 while (regstack
->top
>= 0)
2316 CLEAR_HARD_REG_BIT (regstack
->reg_set
, FIRST_STACK_REG
+ regstack
->top
);
2322 /* Do the actual substitution if any stack regs are mentioned.
2323 Since we only record whether entire insn mentions stack regs, and
2324 subst_stack_regs_pat only works for patterns that contain stack regs,
2325 we must check each pattern in a parallel here. A call_value_pop could
2328 if (stack_regs_mentioned (insn
))
2330 int n_operands
= asm_noperands (PATTERN (insn
));
2331 if (n_operands
>= 0)
2333 /* This insn is an `asm' with operands. Decode the operands,
2334 decide how many are inputs, and do register substitution.
2335 Any REG_UNUSED notes will be handled by subst_asm_stack_regs. */
2337 subst_asm_stack_regs (insn
, regstack
);
2338 return control_flow_insn_deleted
;
2341 if (GET_CODE (PATTERN (insn
)) == PARALLEL
)
2342 for (i
= 0; i
< XVECLEN (PATTERN (insn
), 0); i
++)
2344 if (stack_regs_mentioned_p (XVECEXP (PATTERN (insn
), 0, i
)))
2346 if (GET_CODE (XVECEXP (PATTERN (insn
), 0, i
)) == CLOBBER
)
2347 XVECEXP (PATTERN (insn
), 0, i
)
2348 = shallow_copy_rtx (XVECEXP (PATTERN (insn
), 0, i
));
2349 control_flow_insn_deleted
2350 |= subst_stack_regs_pat (insn
, regstack
,
2351 XVECEXP (PATTERN (insn
), 0, i
));
2355 control_flow_insn_deleted
2356 |= subst_stack_regs_pat (insn
, regstack
, PATTERN (insn
));
2359 /* subst_stack_regs_pat may have deleted a no-op insn. If so, any
2360 REG_UNUSED will already have been dealt with, so just return. */
2362 if (NOTE_P (insn
) || INSN_DELETED_P (insn
))
2363 return control_flow_insn_deleted
;
2365 /* If this a noreturn call, we can't insert pop insns after it.
2366 Instead, reset the stack state to empty. */
2368 && find_reg_note (insn
, REG_NORETURN
, NULL
))
2371 CLEAR_HARD_REG_SET (regstack
->reg_set
);
2372 return control_flow_insn_deleted
;
2375 /* If there is a REG_UNUSED note on a stack register on this insn,
2376 the indicated reg must be popped. The REG_UNUSED note is removed,
2377 since the form of the newly emitted pop insn references the reg,
2378 making it no longer `unset'. */
2380 note_link
= ®_NOTES (insn
);
2381 for (note
= *note_link
; note
; note
= XEXP (note
, 1))
2382 if (REG_NOTE_KIND (note
) == REG_UNUSED
&& STACK_REG_P (XEXP (note
, 0)))
2384 *note_link
= XEXP (note
, 1);
2385 insn
= emit_pop_insn (insn
, regstack
, XEXP (note
, 0), EMIT_AFTER
);
2388 note_link
= &XEXP (note
, 1);
2390 return control_flow_insn_deleted
;
2393 /* Change the organization of the stack so that it fits a new basic
2394 block. Some registers might have to be popped, but there can never be
2395 a register live in the new block that is not now live.
2397 Insert any needed insns before or after INSN, as indicated by
2398 WHERE. OLD is the original stack layout, and NEW is the desired
2399 form. OLD is updated to reflect the code emitted, i.e., it will be
2400 the same as NEW upon return.
2402 This function will not preserve block_end[]. But that information
2403 is no longer needed once this has executed. */
2406 change_stack (rtx insn
, stack_ptr old
, stack_ptr new_stack
, enum emit_where where
)
2412 /* Stack adjustments for the first insn in a block update the
2413 current_block's stack_in instead of inserting insns directly.
2414 compensate_edges will add the necessary code later. */
2417 && where
== EMIT_BEFORE
)
2419 BLOCK_INFO (current_block
)->stack_in
= *new_stack
;
2420 starting_stack_p
= false;
2425 /* We will be inserting new insns "backwards". If we are to insert
2426 after INSN, find the next insn, and insert before it. */
2428 if (where
== EMIT_AFTER
)
2430 if (current_block
&& BB_END (current_block
) == insn
)
2432 insn
= NEXT_INSN (insn
);
2435 /* Initialize partially dead variables. */
2436 for (i
= FIRST_STACK_REG
; i
< LAST_STACK_REG
+ 1; i
++)
2437 if (TEST_HARD_REG_BIT (new_stack
->reg_set
, i
)
2438 && !TEST_HARD_REG_BIT (old
->reg_set
, i
))
2440 old
->reg
[++old
->top
] = i
;
2441 SET_HARD_REG_BIT (old
->reg_set
, i
);
2442 emit_insn_before (gen_rtx_SET (VOIDmode
,
2443 FP_MODE_REG (i
, SFmode
), not_a_num
), insn
);
2446 /* Pop any registers that are not needed in the new block. */
2448 /* If the destination block's stack already has a specified layout
2449 and contains two or more registers, use a more intelligent algorithm
2450 to pop registers that minimizes the number number of fxchs below. */
2451 if (new_stack
->top
> 0)
2453 bool slots
[REG_STACK_SIZE
];
2454 int pops
[REG_STACK_SIZE
];
2455 int next
, dest
, topsrc
;
2457 /* First pass to determine the free slots. */
2458 for (reg
= 0; reg
<= new_stack
->top
; reg
++)
2459 slots
[reg
] = TEST_HARD_REG_BIT (new_stack
->reg_set
, old
->reg
[reg
]);
2461 /* Second pass to allocate preferred slots. */
2463 for (reg
= old
->top
; reg
> new_stack
->top
; reg
--)
2464 if (TEST_HARD_REG_BIT (new_stack
->reg_set
, old
->reg
[reg
]))
2467 for (next
= 0; next
<= new_stack
->top
; next
++)
2468 if (!slots
[next
] && new_stack
->reg
[next
] == old
->reg
[reg
])
2470 /* If this is a preference for the new top of stack, record
2471 the fact by remembering it's old->reg in topsrc. */
2472 if (next
== new_stack
->top
)
2483 /* Intentionally, avoid placing the top of stack in it's correct
2484 location, if we still need to permute the stack below and we
2485 can usefully place it somewhere else. This is the case if any
2486 slot is still unallocated, in which case we should place the
2487 top of stack there. */
2489 for (reg
= 0; reg
< new_stack
->top
; reg
++)
2493 slots
[new_stack
->top
] = false;
2498 /* Third pass allocates remaining slots and emits pop insns. */
2499 next
= new_stack
->top
;
2500 for (reg
= old
->top
; reg
> new_stack
->top
; reg
--)
2505 /* Find next free slot. */
2510 emit_pop_insn (insn
, old
, FP_MODE_REG (old
->reg
[dest
], DFmode
),
2516 /* The following loop attempts to maximize the number of times we
2517 pop the top of the stack, as this permits the use of the faster
2518 ffreep instruction on platforms that support it. */
2522 for (reg
= 0; reg
<= old
->top
; reg
++)
2523 if (TEST_HARD_REG_BIT (new_stack
->reg_set
, old
->reg
[reg
]))
2527 while (old
->top
>= live
)
2528 if (TEST_HARD_REG_BIT (new_stack
->reg_set
, old
->reg
[old
->top
]))
2530 while (TEST_HARD_REG_BIT (new_stack
->reg_set
, old
->reg
[next
]))
2532 emit_pop_insn (insn
, old
, FP_MODE_REG (old
->reg
[next
], DFmode
),
2536 emit_pop_insn (insn
, old
, FP_MODE_REG (old
->reg
[old
->top
], DFmode
),
2540 if (new_stack
->top
== -2)
2542 /* If the new block has never been processed, then it can inherit
2543 the old stack order. */
2545 new_stack
->top
= old
->top
;
2546 memcpy (new_stack
->reg
, old
->reg
, sizeof (new_stack
->reg
));
2550 /* This block has been entered before, and we must match the
2551 previously selected stack order. */
2553 /* By now, the only difference should be the order of the stack,
2554 not their depth or liveliness. */
2556 gcc_assert (hard_reg_set_equal_p (old
->reg_set
, new_stack
->reg_set
));
2557 gcc_assert (old
->top
== new_stack
->top
);
2559 /* If the stack is not empty (new_stack->top != -1), loop here emitting
2560 swaps until the stack is correct.
2562 The worst case number of swaps emitted is N + 2, where N is the
2563 depth of the stack. In some cases, the reg at the top of
2564 stack may be correct, but swapped anyway in order to fix
2565 other regs. But since we never swap any other reg away from
2566 its correct slot, this algorithm will converge. */
2568 if (new_stack
->top
!= -1)
2571 /* Swap the reg at top of stack into the position it is
2572 supposed to be in, until the correct top of stack appears. */
2574 while (old
->reg
[old
->top
] != new_stack
->reg
[new_stack
->top
])
2576 for (reg
= new_stack
->top
; reg
>= 0; reg
--)
2577 if (new_stack
->reg
[reg
] == old
->reg
[old
->top
])
2580 gcc_assert (reg
!= -1);
2582 emit_swap_insn (insn
, old
,
2583 FP_MODE_REG (old
->reg
[reg
], DFmode
));
2586 /* See if any regs remain incorrect. If so, bring an
2587 incorrect reg to the top of stack, and let the while loop
2590 for (reg
= new_stack
->top
; reg
>= 0; reg
--)
2591 if (new_stack
->reg
[reg
] != old
->reg
[reg
])
2593 emit_swap_insn (insn
, old
,
2594 FP_MODE_REG (old
->reg
[reg
], DFmode
));
2599 /* At this point there must be no differences. */
2601 for (reg
= old
->top
; reg
>= 0; reg
--)
2602 gcc_assert (old
->reg
[reg
] == new_stack
->reg
[reg
]);
2606 BB_END (current_block
) = PREV_INSN (insn
);
2609 /* Print stack configuration. */
2612 print_stack (FILE *file
, stack_ptr s
)
2618 fprintf (file
, "uninitialized\n");
2619 else if (s
->top
== -1)
2620 fprintf (file
, "empty\n");
2625 for (i
= 0; i
<= s
->top
; ++i
)
2626 fprintf (file
, "%d ", s
->reg
[i
]);
2627 fputs ("]\n", file
);
2631 /* This function was doing life analysis. We now let the regular live
2632 code do it's job, so we only need to check some extra invariants
2633 that reg-stack expects. Primary among these being that all registers
2634 are initialized before use.
2636 The function returns true when code was emitted to CFG edges and
2637 commit_edge_insertions needs to be called. */
2640 convert_regs_entry (void)
2646 /* Load something into each stack register live at function entry.
2647 Such live registers can be caused by uninitialized variables or
2648 functions not returning values on all paths. In order to keep
2649 the push/pop code happy, and to not scrog the register stack, we
2650 must put something in these registers. Use a QNaN.
2652 Note that we are inserting converted code here. This code is
2653 never seen by the convert_regs pass. */
2655 FOR_EACH_EDGE (e
, ei
, ENTRY_BLOCK_PTR
->succs
)
2657 basic_block block
= e
->dest
;
2658 block_info bi
= BLOCK_INFO (block
);
2661 for (reg
= LAST_STACK_REG
; reg
>= FIRST_STACK_REG
; --reg
)
2662 if (TEST_HARD_REG_BIT (bi
->stack_in
.reg_set
, reg
))
2666 bi
->stack_in
.reg
[++top
] = reg
;
2668 init
= gen_rtx_SET (VOIDmode
,
2669 FP_MODE_REG (FIRST_STACK_REG
, SFmode
),
2671 insert_insn_on_edge (init
, e
);
2675 bi
->stack_in
.top
= top
;
2681 /* Construct the desired stack for function exit. This will either
2682 be `empty', or the function return value at top-of-stack. */
2685 convert_regs_exit (void)
2687 int value_reg_low
, value_reg_high
;
2688 stack_ptr output_stack
;
2691 retvalue
= stack_result (current_function_decl
);
2692 value_reg_low
= value_reg_high
= -1;
2695 value_reg_low
= REGNO (retvalue
);
2696 value_reg_high
= END_HARD_REGNO (retvalue
) - 1;
2699 output_stack
= &BLOCK_INFO (EXIT_BLOCK_PTR
)->stack_in
;
2700 if (value_reg_low
== -1)
2701 output_stack
->top
= -1;
2706 output_stack
->top
= value_reg_high
- value_reg_low
;
2707 for (reg
= value_reg_low
; reg
<= value_reg_high
; ++reg
)
2709 output_stack
->reg
[value_reg_high
- reg
] = reg
;
2710 SET_HARD_REG_BIT (output_stack
->reg_set
, reg
);
2715 /* Copy the stack info from the end of edge E's source block to the
2716 start of E's destination block. */
2719 propagate_stack (edge e
)
2721 stack_ptr src_stack
= &BLOCK_INFO (e
->src
)->stack_out
;
2722 stack_ptr dest_stack
= &BLOCK_INFO (e
->dest
)->stack_in
;
2725 /* Preserve the order of the original stack, but check whether
2726 any pops are needed. */
2727 dest_stack
->top
= -1;
2728 for (reg
= 0; reg
<= src_stack
->top
; ++reg
)
2729 if (TEST_HARD_REG_BIT (dest_stack
->reg_set
, src_stack
->reg
[reg
]))
2730 dest_stack
->reg
[++dest_stack
->top
] = src_stack
->reg
[reg
];
2732 /* Push in any partially dead values. */
2733 for (reg
= FIRST_STACK_REG
; reg
< LAST_STACK_REG
+ 1; reg
++)
2734 if (TEST_HARD_REG_BIT (dest_stack
->reg_set
, reg
)
2735 && !TEST_HARD_REG_BIT (src_stack
->reg_set
, reg
))
2736 dest_stack
->reg
[++dest_stack
->top
] = reg
;
2740 /* Adjust the stack of edge E's source block on exit to match the stack
2741 of it's target block upon input. The stack layouts of both blocks
2742 should have been defined by now. */
2745 compensate_edge (edge e
)
2747 basic_block source
= e
->src
, target
= e
->dest
;
2748 stack_ptr target_stack
= &BLOCK_INFO (target
)->stack_in
;
2749 stack_ptr source_stack
= &BLOCK_INFO (source
)->stack_out
;
2750 struct stack_def regstack
;
2754 fprintf (dump_file
, "Edge %d->%d: ", source
->index
, target
->index
);
2756 gcc_assert (target_stack
->top
!= -2);
2758 /* Check whether stacks are identical. */
2759 if (target_stack
->top
== source_stack
->top
)
2761 for (reg
= target_stack
->top
; reg
>= 0; --reg
)
2762 if (target_stack
->reg
[reg
] != source_stack
->reg
[reg
])
2768 fprintf (dump_file
, "no changes needed\n");
2775 fprintf (dump_file
, "correcting stack to ");
2776 print_stack (dump_file
, target_stack
);
2779 /* Abnormal calls may appear to have values live in st(0), but the
2780 abnormal return path will not have actually loaded the values. */
2781 if (e
->flags
& EDGE_ABNORMAL_CALL
)
2783 /* Assert that the lifetimes are as we expect -- one value
2784 live at st(0) on the end of the source block, and no
2785 values live at the beginning of the destination block.
2786 For complex return values, we may have st(1) live as well. */
2787 gcc_assert (source_stack
->top
== 0 || source_stack
->top
== 1);
2788 gcc_assert (target_stack
->top
== -1);
2792 /* Handle non-call EH edges specially. The normal return path have
2793 values in registers. These will be popped en masse by the unwind
2795 if (e
->flags
& EDGE_EH
)
2797 gcc_assert (target_stack
->top
== -1);
2801 /* We don't support abnormal edges. Global takes care to
2802 avoid any live register across them, so we should never
2803 have to insert instructions on such edges. */
2804 gcc_assert (! (e
->flags
& EDGE_ABNORMAL
));
2806 /* Make a copy of source_stack as change_stack is destructive. */
2807 regstack
= *source_stack
;
2809 /* It is better to output directly to the end of the block
2810 instead of to the edge, because emit_swap can do minimal
2811 insn scheduling. We can do this when there is only one
2812 edge out, and it is not abnormal. */
2813 if (EDGE_COUNT (source
->succs
) == 1)
2815 current_block
= source
;
2816 change_stack (BB_END (source
), ®stack
, target_stack
,
2817 (JUMP_P (BB_END (source
)) ? EMIT_BEFORE
: EMIT_AFTER
));
2823 current_block
= NULL
;
2826 /* ??? change_stack needs some point to emit insns after. */
2827 after
= emit_note (NOTE_INSN_DELETED
);
2829 change_stack (after
, ®stack
, target_stack
, EMIT_BEFORE
);
2834 insert_insn_on_edge (seq
, e
);
2840 /* Traverse all non-entry edges in the CFG, and emit the necessary
2841 edge compensation code to change the stack from stack_out of the
2842 source block to the stack_in of the destination block. */
2845 compensate_edges (void)
2847 bool inserted
= false;
2850 starting_stack_p
= false;
2853 if (bb
!= ENTRY_BLOCK_PTR
)
2858 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2859 inserted
|= compensate_edge (e
);
2864 /* Select the better of two edges E1 and E2 to use to determine the
2865 stack layout for their shared destination basic block. This is
2866 typically the more frequently executed. The edge E1 may be NULL
2867 (in which case E2 is returned), but E2 is always non-NULL. */
2870 better_edge (edge e1
, edge e2
)
2875 if (EDGE_FREQUENCY (e1
) > EDGE_FREQUENCY (e2
))
2877 if (EDGE_FREQUENCY (e1
) < EDGE_FREQUENCY (e2
))
2880 if (e1
->count
> e2
->count
)
2882 if (e1
->count
< e2
->count
)
2885 /* Prefer critical edges to minimize inserting compensation code on
2888 if (EDGE_CRITICAL_P (e1
) != EDGE_CRITICAL_P (e2
))
2889 return EDGE_CRITICAL_P (e1
) ? e1
: e2
;
2891 /* Avoid non-deterministic behavior. */
2892 return (e1
->src
->index
< e2
->src
->index
) ? e1
: e2
;
2895 /* Convert stack register references in one block. Return true if the CFG
2896 has been modified in the process. */
2899 convert_regs_1 (basic_block block
)
2901 struct stack_def regstack
;
2902 block_info bi
= BLOCK_INFO (block
);
2905 bool control_flow_insn_deleted
= false;
2906 bool cfg_altered
= false;
2907 int debug_insns_with_starting_stack
= 0;
2909 any_malformed_asm
= false;
2911 /* Choose an initial stack layout, if one hasn't already been chosen. */
2912 if (bi
->stack_in
.top
== -2)
2914 edge e
, beste
= NULL
;
2917 /* Select the best incoming edge (typically the most frequent) to
2918 use as a template for this basic block. */
2919 FOR_EACH_EDGE (e
, ei
, block
->preds
)
2920 if (BLOCK_INFO (e
->src
)->done
)
2921 beste
= better_edge (beste
, e
);
2924 propagate_stack (beste
);
2927 /* No predecessors. Create an arbitrary input stack. */
2928 bi
->stack_in
.top
= -1;
2929 for (reg
= LAST_STACK_REG
; reg
>= FIRST_STACK_REG
; --reg
)
2930 if (TEST_HARD_REG_BIT (bi
->stack_in
.reg_set
, reg
))
2931 bi
->stack_in
.reg
[++bi
->stack_in
.top
] = reg
;
2937 fprintf (dump_file
, "\nBasic block %d\nInput stack: ", block
->index
);
2938 print_stack (dump_file
, &bi
->stack_in
);
2941 /* Process all insns in this block. Keep track of NEXT so that we
2942 don't process insns emitted while substituting in INSN. */
2943 current_block
= block
;
2944 next
= BB_HEAD (block
);
2945 regstack
= bi
->stack_in
;
2946 starting_stack_p
= true;
2951 next
= NEXT_INSN (insn
);
2953 /* Ensure we have not missed a block boundary. */
2955 if (insn
== BB_END (block
))
2958 /* Don't bother processing unless there is a stack reg
2959 mentioned or if it's a CALL_INSN. */
2960 if (DEBUG_INSN_P (insn
))
2962 if (starting_stack_p
)
2963 debug_insns_with_starting_stack
++;
2966 subst_all_stack_regs_in_debug_insn (insn
, ®stack
);
2968 /* Nothing must ever die at a debug insn. If something
2969 is referenced in it that becomes dead, it should have
2970 died before and the reference in the debug insn
2971 should have been removed so as to avoid changing code
2973 gcc_assert (!find_reg_note (insn
, REG_DEAD
, NULL
));
2976 else if (stack_regs_mentioned (insn
)
2981 fprintf (dump_file
, " insn %d input stack: ",
2983 print_stack (dump_file
, ®stack
);
2985 control_flow_insn_deleted
|= subst_stack_regs (insn
, ®stack
);
2986 starting_stack_p
= false;
2991 if (debug_insns_with_starting_stack
)
2993 /* Since it's the first non-debug instruction that determines
2994 the stack requirements of the current basic block, we refrain
2995 from updating debug insns before it in the loop above, and
2996 fix them up here. */
2997 for (insn
= BB_HEAD (block
); debug_insns_with_starting_stack
;
2998 insn
= NEXT_INSN (insn
))
3000 if (!DEBUG_INSN_P (insn
))
3003 debug_insns_with_starting_stack
--;
3004 subst_all_stack_regs_in_debug_insn (insn
, &bi
->stack_in
);
3010 fprintf (dump_file
, "Expected live registers [");
3011 for (reg
= FIRST_STACK_REG
; reg
<= LAST_STACK_REG
; ++reg
)
3012 if (TEST_HARD_REG_BIT (bi
->out_reg_set
, reg
))
3013 fprintf (dump_file
, " %d", reg
);
3014 fprintf (dump_file
, " ]\nOutput stack: ");
3015 print_stack (dump_file
, ®stack
);
3018 insn
= BB_END (block
);
3020 insn
= PREV_INSN (insn
);
3022 /* If the function is declared to return a value, but it returns one
3023 in only some cases, some registers might come live here. Emit
3024 necessary moves for them. */
3026 for (reg
= FIRST_STACK_REG
; reg
<= LAST_STACK_REG
; ++reg
)
3028 if (TEST_HARD_REG_BIT (bi
->out_reg_set
, reg
)
3029 && ! TEST_HARD_REG_BIT (regstack
.reg_set
, reg
))
3034 fprintf (dump_file
, "Emitting insn initializing reg %d\n", reg
);
3036 set
= gen_rtx_SET (VOIDmode
, FP_MODE_REG (reg
, SFmode
), not_a_num
);
3037 insn
= emit_insn_after (set
, insn
);
3038 control_flow_insn_deleted
|= subst_stack_regs (insn
, ®stack
);
3042 /* Amongst the insns possibly deleted during the substitution process above,
3043 might have been the only trapping insn in the block. We purge the now
3044 possibly dead EH edges here to avoid an ICE from fixup_abnormal_edges,
3045 called at the end of convert_regs. The order in which we process the
3046 blocks ensures that we never delete an already processed edge.
3048 Note that, at this point, the CFG may have been damaged by the emission
3049 of instructions after an abnormal call, which moves the basic block end
3050 (and is the reason why we call fixup_abnormal_edges later). So we must
3051 be sure that the trapping insn has been deleted before trying to purge
3052 dead edges, otherwise we risk purging valid edges.
3054 ??? We are normally supposed not to delete trapping insns, so we pretend
3055 that the insns deleted above don't actually trap. It would have been
3056 better to detect this earlier and avoid creating the EH edge in the first
3057 place, still, but we don't have enough information at that time. */
3059 if (control_flow_insn_deleted
)
3060 cfg_altered
|= purge_dead_edges (block
);
3062 /* Something failed if the stack lives don't match. If we had malformed
3063 asms, we zapped the instruction itself, but that didn't produce the
3064 same pattern of register kills as before. */
3066 gcc_assert (hard_reg_set_equal_p (regstack
.reg_set
, bi
->out_reg_set
)
3067 || any_malformed_asm
);
3068 bi
->stack_out
= regstack
;
3074 /* Convert registers in all blocks reachable from BLOCK. Return true if the
3075 CFG has been modified in the process. */
3078 convert_regs_2 (basic_block block
)
3080 basic_block
*stack
, *sp
;
3081 bool cfg_altered
= false;
3083 /* We process the blocks in a top-down manner, in a way such that one block
3084 is only processed after all its predecessors. The number of predecessors
3085 of every block has already been computed. */
3087 stack
= XNEWVEC (basic_block
, n_basic_blocks
);
3099 /* Processing BLOCK is achieved by convert_regs_1, which may purge
3100 some dead EH outgoing edge after the deletion of the trapping
3101 insn inside the block. Since the number of predecessors of
3102 BLOCK's successors was computed based on the initial edge set,
3103 we check the necessity to process some of these successors
3104 before such an edge deletion may happen. However, there is
3105 a pitfall: if BLOCK is the only predecessor of a successor and
3106 the edge between them happens to be deleted, the successor
3107 becomes unreachable and should not be processed. The problem
3108 is that there is no way to preventively detect this case so we
3109 stack the successor in all cases and hand over the task of
3110 fixing up the discrepancy to convert_regs_1. */
3112 FOR_EACH_EDGE (e
, ei
, block
->succs
)
3113 if (! (e
->flags
& EDGE_DFS_BACK
))
3115 BLOCK_INFO (e
->dest
)->predecessors
--;
3116 if (!BLOCK_INFO (e
->dest
)->predecessors
)
3120 cfg_altered
|= convert_regs_1 (block
);
3122 while (sp
!= stack
);
3129 /* Traverse all basic blocks in a function, converting the register
3130 references in each insn from the "flat" register file that gcc uses,
3131 to the stack-like registers the 387 uses. */
3136 bool cfg_altered
= false;
3142 /* Initialize uninitialized registers on function entry. */
3143 inserted
= convert_regs_entry ();
3145 /* Construct the desired stack for function exit. */
3146 convert_regs_exit ();
3147 BLOCK_INFO (EXIT_BLOCK_PTR
)->done
= 1;
3149 /* ??? Future: process inner loops first, and give them arbitrary
3150 initial stacks which emit_swap_insn can modify. This ought to
3151 prevent double fxch that often appears at the head of a loop. */
3153 /* Process all blocks reachable from all entry points. */
3154 FOR_EACH_EDGE (e
, ei
, ENTRY_BLOCK_PTR
->succs
)
3155 cfg_altered
|= convert_regs_2 (e
->dest
);
3157 /* ??? Process all unreachable blocks. Though there's no excuse
3158 for keeping these even when not optimizing. */
3161 block_info bi
= BLOCK_INFO (b
);
3164 cfg_altered
|= convert_regs_2 (b
);
3167 /* We must fix up abnormal edges before inserting compensation code
3168 because both mechanisms insert insns on edges. */
3169 inserted
|= fixup_abnormal_edges ();
3171 inserted
|= compensate_edges ();
3173 clear_aux_for_blocks ();
3176 commit_edge_insertions ();
3182 fputc ('\n', dump_file
);
3185 /* Convert register usage from "flat" register file usage to a "stack
3186 register file. FILE is the dump file, if used.
3188 Construct a CFG and run life analysis. Then convert each insn one
3189 by one. Run a last cleanup_cfg pass, if optimizing, to eliminate
3190 code duplication created when the converter inserts pop insns on
3200 /* Clean up previous run. */
3201 stack_regs_mentioned_data
.release ();
3203 /* See if there is something to do. Flow analysis is quite
3204 expensive so we might save some compilation time. */
3205 for (i
= FIRST_STACK_REG
; i
<= LAST_STACK_REG
; i
++)
3206 if (df_regs_ever_live_p (i
))
3208 if (i
> LAST_STACK_REG
)
3211 df_note_add_problem ();
3214 mark_dfs_back_edges ();
3216 /* Set up block info for each basic block. */
3217 alloc_aux_for_blocks (sizeof (struct block_info_def
));
3220 block_info bi
= BLOCK_INFO (bb
);
3225 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3226 if (!(e
->flags
& EDGE_DFS_BACK
)
3227 && e
->src
!= ENTRY_BLOCK_PTR
)
3230 /* Set current register status at last instruction `uninitialized'. */
3231 bi
->stack_in
.top
= -2;
3233 /* Copy live_at_end and live_at_start into temporaries. */
3234 for (reg
= FIRST_STACK_REG
; reg
<= LAST_STACK_REG
; reg
++)
3236 if (REGNO_REG_SET_P (DF_LR_OUT (bb
), reg
))
3237 SET_HARD_REG_BIT (bi
->out_reg_set
, reg
);
3238 if (REGNO_REG_SET_P (DF_LR_IN (bb
), reg
))
3239 SET_HARD_REG_BIT (bi
->stack_in
.reg_set
, reg
);
3243 /* Create the replacement registers up front. */
3244 for (i
= FIRST_STACK_REG
; i
<= LAST_STACK_REG
; i
++)
3246 enum machine_mode mode
;
3247 for (mode
= GET_CLASS_NARROWEST_MODE (MODE_FLOAT
);
3249 mode
= GET_MODE_WIDER_MODE (mode
))
3250 FP_MODE_REG (i
, mode
) = gen_rtx_REG (mode
, i
);
3251 for (mode
= GET_CLASS_NARROWEST_MODE (MODE_COMPLEX_FLOAT
);
3253 mode
= GET_MODE_WIDER_MODE (mode
))
3254 FP_MODE_REG (i
, mode
) = gen_rtx_REG (mode
, i
);
3257 ix86_flags_rtx
= gen_rtx_REG (CCmode
, FLAGS_REG
);
3259 /* A QNaN for initializing uninitialized variables.
3261 ??? We can't load from constant memory in PIC mode, because
3262 we're inserting these instructions before the prologue and
3263 the PIC register hasn't been set up. In that case, fall back
3264 on zero, which we can get from `fldz'. */
3266 if ((flag_pic
&& !TARGET_64BIT
)
3267 || ix86_cmodel
== CM_LARGE
|| ix86_cmodel
== CM_LARGE_PIC
)
3268 not_a_num
= CONST0_RTX (SFmode
);
3273 real_nan (&r
, "", 1, SFmode
);
3274 not_a_num
= CONST_DOUBLE_FROM_REAL_VALUE (r
, SFmode
);
3275 not_a_num
= force_const_mem (SFmode
, not_a_num
);
3278 /* Allocate a cache for stack_regs_mentioned. */
3279 max_uid
= get_max_uid ();
3280 stack_regs_mentioned_data
.create (max_uid
+ 1);
3281 memset (stack_regs_mentioned_data
.address (),
3282 0, sizeof (char) * (max_uid
+ 1));
3286 free_aux_for_blocks ();
3289 #endif /* STACK_REGS */
3292 gate_handle_stack_regs (void)
3301 struct rtl_opt_pass pass_stack_regs
=
3305 "*stack_regs", /* name */
3306 OPTGROUP_NONE
, /* optinfo_flags */
3307 gate_handle_stack_regs
, /* gate */
3311 0, /* static_pass_number */
3312 TV_REG_STACK
, /* tv_id */
3313 0, /* properties_required */
3314 0, /* properties_provided */
3315 0, /* properties_destroyed */
3316 0, /* todo_flags_start */
3317 0 /* todo_flags_finish */
3321 /* Convert register usage from flat register file usage to a stack
3324 rest_of_handle_stack_regs (void)
3328 regstack_completed
= 1;
3333 struct rtl_opt_pass pass_stack_regs_run
=
3338 OPTGROUP_NONE
, /* optinfo_flags */
3340 rest_of_handle_stack_regs
, /* execute */
3343 0, /* static_pass_number */
3344 TV_REG_STACK
, /* tv_id */
3345 0, /* properties_required */
3346 0, /* properties_provided */
3347 0, /* properties_destroyed */
3348 0, /* todo_flags_start */
3349 TODO_df_finish
| TODO_verify_rtl_sharing
|
3350 TODO_ggc_collect
/* todo_flags_finish */