1 /* Register to Stack convert for GNU compiler.
2 Copyright (C) 1992, 93, 94, 95, 96, 97, 1998 Free Software Foundation, Inc.
4 This file is part of GNU CC.
6 GNU CC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GNU CC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU CC; see the file COPYING. If not, write to
18 the Free Software Foundation, 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
21 /* This pass converts stack-like registers from the "flat register
22 file" model that gcc uses, to a stack convention that the 387 uses.
24 * The form of the input:
26 On input, the function consists of insn that have had their
27 registers fully allocated to a set of "virtual" registers. Note that
28 the word "virtual" is used differently here than elsewhere in gcc: for
29 each virtual stack reg, there is a hard reg, but the mapping between
30 them is not known until this pass is run. On output, hard register
31 numbers have been substituted, and various pop and exchange insns have
32 been emitted. The hard register numbers and the virtual register
33 numbers completely overlap - before this pass, all stack register
34 numbers are virtual, and afterward they are all hard.
36 The virtual registers can be manipulated normally by gcc, and their
37 semantics are the same as for normal registers. After the hard
38 register numbers are substituted, the semantics of an insn containing
39 stack-like regs are not the same as for an insn with normal regs: for
40 instance, it is not safe to delete an insn that appears to be a no-op
41 move. In general, no insn containing hard regs should be changed
42 after this pass is done.
44 * The form of the output:
46 After this pass, hard register numbers represent the distance from
47 the current top of stack to the desired register. A reference to
48 FIRST_STACK_REG references the top of stack, FIRST_STACK_REG + 1,
49 represents the register just below that, and so forth. Also, REG_DEAD
50 notes indicate whether or not a stack register should be popped.
52 A "swap" insn looks like a parallel of two patterns, where each
53 pattern is a SET: one sets A to B, the other B to A.
55 A "push" or "load" insn is a SET whose SET_DEST is FIRST_STACK_REG
56 and whose SET_DEST is REG or MEM. Any other SET_DEST, such as PLUS,
57 will replace the existing stack top, not push a new value.
59 A store insn is a SET whose SET_DEST is FIRST_STACK_REG, and whose
60 SET_SRC is REG or MEM.
62 The case where the SET_SRC and SET_DEST are both FIRST_STACK_REG
63 appears ambiguous. As a special case, the presence of a REG_DEAD note
64 for FIRST_STACK_REG differentiates between a load insn and a pop.
66 If a REG_DEAD is present, the insn represents a "pop" that discards
67 the top of the register stack. If there is no REG_DEAD note, then the
68 insn represents a "dup" or a push of the current top of stack onto the
73 Existing REG_DEAD and REG_UNUSED notes for stack registers are
74 deleted and recreated from scratch. REG_DEAD is never created for a
75 SET_DEST, only REG_UNUSED.
77 Before life analysis, the mode of each insn is set based on whether
78 or not any stack registers are mentioned within that insn. VOIDmode
79 means that no regs are mentioned anyway, and QImode means that at
80 least one pattern within the insn mentions stack registers. This
81 information is valid until after reg_to_stack returns, and is used
86 There are several rules on the usage of stack-like regs in
87 asm_operands insns. These rules apply only to the operands that are
90 1. Given a set of input regs that die in an asm_operands, it is
91 necessary to know which are implicitly popped by the asm, and
92 which must be explicitly popped by gcc.
94 An input reg that is implicitly popped by the asm must be
95 explicitly clobbered, unless it is constrained to match an
98 2. For any input reg that is implicitly popped by an asm, it is
99 necessary to know how to adjust the stack to compensate for the pop.
100 If any non-popped input is closer to the top of the reg-stack than
101 the implicitly popped reg, it would not be possible to know what the
102 stack looked like - it's not clear how the rest of the stack "slides
105 All implicitly popped input regs must be closer to the top of
106 the reg-stack than any input that is not implicitly popped.
108 3. It is possible that if an input dies in an insn, reload might
109 use the input reg for an output reload. Consider this example:
111 asm ("foo" : "=t" (a) : "f" (b));
113 This asm says that input B is not popped by the asm, and that
114 the asm pushes a result onto the reg-stack, ie, the stack is one
115 deeper after the asm than it was before. But, it is possible that
116 reload will think that it can use the same reg for both the input and
117 the output, if input B dies in this insn.
119 If any input operand uses the "f" constraint, all output reg
120 constraints must use the "&" earlyclobber.
122 The asm above would be written as
124 asm ("foo" : "=&t" (a) : "f" (b));
126 4. Some operands need to be in particular places on the stack. All
127 output operands fall in this category - there is no other way to
128 know which regs the outputs appear in unless the user indicates
129 this in the constraints.
131 Output operands must specifically indicate which reg an output
132 appears in after an asm. "=f" is not allowed: the operand
133 constraints must select a class with a single reg.
135 5. Output operands may not be "inserted" between existing stack regs.
136 Since no 387 opcode uses a read/write operand, all output operands
137 are dead before the asm_operands, and are pushed by the asm_operands.
138 It makes no sense to push anywhere but the top of the reg-stack.
140 Output operands must start at the top of the reg-stack: output
141 operands may not "skip" a reg.
143 6. Some asm statements may need extra stack space for internal
144 calculations. This can be guaranteed by clobbering stack registers
145 unrelated to the inputs and outputs.
147 Here are a couple of reasonable asms to want to write. This asm
148 takes one input, which is internally popped, and produces two outputs.
150 asm ("fsincos" : "=t" (cos), "=u" (sin) : "0" (inp));
152 This asm takes two inputs, which are popped by the fyl2xp1 opcode,
153 and replaces them with one output. The user must code the "st(1)"
154 clobber for reg-stack.c to know that fyl2xp1 pops both inputs.
156 asm ("fyl2xp1" : "=t" (result) : "0" (x), "u" (y) : "st(1)");
164 #include "insn-config.h"
166 #include "hard-reg-set.h"
168 #include "insn-flags.h"
173 #define REG_STACK_SIZE (LAST_STACK_REG - FIRST_STACK_REG + 1)
175 /* This is the basic stack record. TOP is an index into REG[] such
176 that REG[TOP] is the top of stack. If TOP is -1 the stack is empty.
178 If TOP is -2, REG[] is not yet initialized. Stack initialization
179 consists of placing each live reg in array `reg' and setting `top'
182 REG_SET indicates which registers are live. */
184 typedef struct stack_def
186 int top; /* index to top stack element */
187 HARD_REG_SET reg_set; /* set of live registers */
188 char reg[REG_STACK_SIZE]; /* register - stack mapping */
191 /* highest instruction uid */
192 static int max_uid = 0;
194 /* Number of basic blocks in the current function. */
197 /* Element N is first insn in basic block N.
198 This info lasts until we finish compiling the function. */
199 static rtx *block_begin;
201 /* Element N is last insn in basic block N.
202 This info lasts until we finish compiling the function. */
203 static rtx *block_end;
205 /* Element N is nonzero if control can drop into basic block N */
206 static char *block_drops_in;
208 /* Element N says all about the stack at entry block N */
209 static stack block_stack_in;
211 /* Element N says all about the stack life at the end of block N */
212 static HARD_REG_SET *block_out_reg_set;
214 /* This is where the BLOCK_NUM values are really stored. This is set
215 up by find_blocks and used there and in life_analysis. It can be used
216 later, but only to look up an insn that is the head or tail of some
217 block. life_analysis and the stack register conversion process can
218 add insns within a block. */
219 static int *block_number;
221 /* This is the register file for all register after conversion */
223 FP_mode_reg[LAST_STACK_REG+1-FIRST_STACK_REG][(int) MAX_MACHINE_MODE];
225 #define FP_MODE_REG(regno,mode) \
226 (FP_mode_reg[(regno)-FIRST_STACK_REG][(int)(mode)])
228 /* Get the basic block number of an insn. See note at block_number
229 definition are validity of this information. */
231 #define BLOCK_NUM(INSN) \
232 ((INSN_UID (INSN) > max_uid) \
233 ? (abort() , -1) : block_number[INSN_UID (INSN)])
235 extern rtx forced_labels;
237 /* Forward declarations */
239 static void mark_regs_pat PROTO((rtx, HARD_REG_SET *));
240 static void straighten_stack PROTO((rtx, stack));
241 static void pop_stack PROTO((stack, int));
242 static void record_label_references PROTO((rtx, rtx));
243 static rtx *get_true_reg PROTO((rtx *));
244 static int constrain_asm_operands PROTO((int, rtx *, char **, int *,
247 static void record_asm_reg_life PROTO((rtx,stack, rtx *, char **,
249 static void record_reg_life_pat PROTO((rtx, HARD_REG_SET *,
250 HARD_REG_SET *, int));
251 static void get_asm_operand_lengths PROTO((rtx, int, int *, int *));
252 static void record_reg_life PROTO((rtx, int, stack));
253 static void find_blocks PROTO((rtx));
254 static rtx stack_result PROTO((tree));
255 static void stack_reg_life_analysis PROTO((rtx, HARD_REG_SET *));
256 static void replace_reg PROTO((rtx *, int));
257 static void remove_regno_note PROTO((rtx, enum reg_note, int));
258 static int get_hard_regnum PROTO((stack, rtx));
259 static void delete_insn_for_stacker PROTO((rtx));
260 static rtx emit_pop_insn PROTO((rtx, stack, rtx, rtx (*) ()));
261 static void emit_swap_insn PROTO((rtx, stack, rtx));
262 static void move_for_stack_reg PROTO((rtx, stack, rtx));
263 static void swap_rtx_condition PROTO((rtx));
264 static void compare_for_stack_reg PROTO((rtx, stack, rtx));
265 static void subst_stack_regs_pat PROTO((rtx, stack, rtx));
266 static void subst_asm_stack_regs PROTO((rtx, stack, rtx *, rtx **,
268 static void subst_stack_regs PROTO((rtx, stack));
269 static void change_stack PROTO((rtx, stack, stack, rtx (*) ()));
271 static void goto_block_pat PROTO((rtx, stack, rtx));
272 static void convert_regs PROTO((void));
273 static void print_blocks PROTO((FILE *, rtx, rtx));
274 static void dump_stack_info PROTO((FILE *));
276 /* Mark all registers needed for this pattern. */
279 mark_regs_pat (pat, set)
283 enum machine_mode mode;
287 if (GET_CODE (pat) == SUBREG)
289 mode = GET_MODE (pat);
290 regno = SUBREG_WORD (pat);
291 regno += REGNO (SUBREG_REG (pat));
294 regno = REGNO (pat), mode = GET_MODE (pat);
296 for (count = HARD_REGNO_NREGS (regno, mode);
297 count; count--, regno++)
298 SET_HARD_REG_BIT (*set, regno);
301 /* Reorganise the stack into ascending numbers,
305 straighten_stack (insn, regstack)
309 struct stack_def temp_stack;
312 temp_stack.reg_set = regstack->reg_set;
314 for (top = temp_stack.top = regstack->top; top >= 0; top--)
315 temp_stack.reg[top] = FIRST_STACK_REG + temp_stack.top - top;
317 change_stack (insn, regstack, &temp_stack, emit_insn_after);
320 /* Pop a register from the stack */
323 pop_stack (regstack, regno)
327 int top = regstack->top;
329 CLEAR_HARD_REG_BIT (regstack->reg_set, regno);
331 /* If regno was not at the top of stack then adjust stack */
332 if (regstack->reg [top] != regno)
335 for (i = regstack->top; i >= 0; i--)
336 if (regstack->reg [i] == regno)
339 for (j = i; j < top; j++)
340 regstack->reg [j] = regstack->reg [j + 1];
346 /* Return non-zero if any stack register is mentioned somewhere within PAT. */
349 stack_regs_mentioned_p (pat)
355 if (STACK_REG_P (pat))
358 fmt = GET_RTX_FORMAT (GET_CODE (pat));
359 for (i = GET_RTX_LENGTH (GET_CODE (pat)) - 1; i >= 0; i--)
365 for (j = XVECLEN (pat, i) - 1; j >= 0; j--)
366 if (stack_regs_mentioned_p (XVECEXP (pat, i, j)))
369 else if (fmt[i] == 'e' && stack_regs_mentioned_p (XEXP (pat, i)))
376 /* Convert register usage from "flat" register file usage to a "stack
377 register file. FIRST is the first insn in the function, FILE is the
380 First compute the beginning and end of each basic block. Do a
381 register life analysis on the stack registers, recording the result
382 for the head and tail of each basic block. The convert each insn one
383 by one. Run a last jump_optimize() pass, if optimizing, to eliminate
384 any cross-jumping created when the converter inserts pop insns.*/
387 reg_to_stack (first, file)
393 int stack_reg_seen = 0;
394 enum machine_mode mode;
395 HARD_REG_SET stackentry;
397 CLEAR_HARD_REG_SET (stackentry);
400 static int initialised;
404 initialised = 1; /* This array can not have been previously
405 initialised, because the rtx's are
406 thrown away between compilations of
409 for (i = FIRST_STACK_REG; i <= LAST_STACK_REG; i++)
411 for (mode = GET_CLASS_NARROWEST_MODE (MODE_FLOAT); mode != VOIDmode;
412 mode = GET_MODE_WIDER_MODE (mode))
413 FP_MODE_REG (i, mode) = gen_rtx_REG (mode, i);
414 for (mode = GET_CLASS_NARROWEST_MODE (MODE_COMPLEX_FLOAT); mode != VOIDmode;
415 mode = GET_MODE_WIDER_MODE (mode))
416 FP_MODE_REG (i, mode) = gen_rtx_REG (mode, i);
421 /* Count the basic blocks. Also find maximum insn uid. */
423 register RTX_CODE prev_code = BARRIER;
424 register RTX_CODE code;
425 register int before_function_beg = 1;
429 for (insn = first; insn; insn = NEXT_INSN (insn))
431 /* Note that this loop must select the same block boundaries
432 as code in find_blocks. Also note that this code is not the
433 same as that used in flow.c. */
435 if (INSN_UID (insn) > max_uid)
436 max_uid = INSN_UID (insn);
438 code = GET_CODE (insn);
440 if (code == CODE_LABEL
441 || (prev_code != INSN
442 && prev_code != CALL_INSN
443 && prev_code != CODE_LABEL
444 && GET_RTX_CLASS (code) == 'i'))
447 if (code == NOTE && NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_BEG)
448 before_function_beg = 0;
450 /* Remember whether or not this insn mentions an FP regs.
451 Check JUMP_INSNs too, in case someone creates a funny PARALLEL. */
453 if (GET_RTX_CLASS (code) == 'i'
454 && stack_regs_mentioned_p (PATTERN (insn)))
457 PUT_MODE (insn, QImode);
459 /* Note any register passing parameters. */
461 if (before_function_beg && code == INSN
462 && GET_CODE (PATTERN (insn)) == USE)
463 record_reg_life_pat (PATTERN (insn), (HARD_REG_SET *) 0,
467 PUT_MODE (insn, VOIDmode);
469 if (code == CODE_LABEL)
470 LABEL_REFS (insn) = insn; /* delete old chain */
477 /* If no stack register reference exists in this insn, there isn't
478 anything to convert. */
480 if (! stack_reg_seen)
483 /* If there are stack registers, there must be at least one block. */
488 /* Allocate some tables that last till end of compiling this function
489 and some needed only in find_blocks and life_analysis. */
491 block_begin = (rtx *) alloca (blocks * sizeof (rtx));
492 block_end = (rtx *) alloca (blocks * sizeof (rtx));
493 block_drops_in = (char *) alloca (blocks);
495 block_stack_in = (stack) alloca (blocks * sizeof (struct stack_def));
496 block_out_reg_set = (HARD_REG_SET *) alloca (blocks * sizeof (HARD_REG_SET));
497 bzero ((char *) block_stack_in, blocks * sizeof (struct stack_def));
498 bzero ((char *) block_out_reg_set, blocks * sizeof (HARD_REG_SET));
500 block_number = (int *) alloca ((max_uid + 1) * sizeof (int));
503 stack_reg_life_analysis (first, &stackentry);
505 /* Dump the life analysis debug information before jump
506 optimization, as that will destroy the LABEL_REFS we keep the
510 dump_stack_info (file);
515 jump_optimize (first, 2, 0, 0);
518 /* Check PAT, which is in INSN, for LABEL_REFs. Add INSN to the
519 label's chain of references, and note which insn contains each
523 record_label_references (insn, pat)
526 register enum rtx_code code = GET_CODE (pat);
530 if (code == LABEL_REF)
532 register rtx label = XEXP (pat, 0);
535 if (GET_CODE (label) != CODE_LABEL)
538 /* If this is an undefined label, LABEL_REFS (label) contains
540 if (INSN_UID (label) == 0)
543 /* Don't make a duplicate in the code_label's chain. */
545 for (ref = LABEL_REFS (label);
547 ref = LABEL_NEXTREF (ref))
548 if (CONTAINING_INSN (ref) == insn)
551 CONTAINING_INSN (pat) = insn;
552 LABEL_NEXTREF (pat) = LABEL_REFS (label);
553 LABEL_REFS (label) = pat;
558 fmt = GET_RTX_FORMAT (code);
559 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
562 record_label_references (insn, XEXP (pat, i));
566 for (j = 0; j < XVECLEN (pat, i); j++)
567 record_label_references (insn, XVECEXP (pat, i, j));
572 /* Return a pointer to the REG expression within PAT. If PAT is not a
573 REG, possible enclosed by a conversion rtx, return the inner part of
574 PAT that stopped the search. */
581 switch (GET_CODE (*pat))
584 /* eliminate FP subregister accesses in favour of the
585 actual FP register in use. */
588 if (FP_REG_P (subreg = SUBREG_REG (*pat)))
590 *pat = FP_MODE_REG (REGNO (subreg) + SUBREG_WORD (*pat),
599 pat = & XEXP (*pat, 0);
603 /* Scan the OPERANDS and OPERAND_CONSTRAINTS of an asm_operands.
604 N_OPERANDS is the total number of operands. Return which alternative
605 matched, or -1 is no alternative matches.
607 OPERAND_MATCHES is an array which indicates which operand this
608 operand matches due to the constraints, or -1 if no match is required.
609 If two operands match by coincidence, but are not required to match by
610 the constraints, -1 is returned.
612 OPERAND_CLASS is an array which indicates the smallest class
613 required by the constraints. If the alternative that matches calls
614 for some class `class', and the operand matches a subclass of `class',
615 OPERAND_CLASS is set to `class' as required by the constraints, not to
616 the subclass. If an alternative allows more than one class,
617 OPERAND_CLASS is set to the smallest class that is a union of the
621 constrain_asm_operands (n_operands, operands, operand_constraints,
622 operand_matches, operand_class)
625 char **operand_constraints;
626 int *operand_matches;
627 enum reg_class *operand_class;
629 char **constraints = (char **) alloca (n_operands * sizeof (char *));
631 int this_alternative, this_operand;
635 for (j = 0; j < n_operands; j++)
636 constraints[j] = operand_constraints[j];
638 /* Compute the number of alternatives in the operands. reload has
639 already guaranteed that all operands have the same number of
647 for (q = constraints[0]; *q; q++)
648 n_alternatives += (*q == ',');
651 this_alternative = 0;
652 while (this_alternative < n_alternatives)
657 /* No operands match, no narrow class requirements yet. */
658 for (i = 0; i < n_operands; i++)
660 operand_matches[i] = -1;
661 operand_class[i] = NO_REGS;
664 for (this_operand = 0; this_operand < n_operands; this_operand++)
666 rtx op = operands[this_operand];
667 enum machine_mode mode = GET_MODE (op);
668 char *p = constraints[this_operand];
673 if (GET_CODE (op) == SUBREG)
675 if (GET_CODE (SUBREG_REG (op)) == REG
676 && REGNO (SUBREG_REG (op)) < FIRST_PSEUDO_REGISTER)
677 offset = SUBREG_WORD (op);
678 op = SUBREG_REG (op);
681 /* An empty constraint or empty alternative
682 allows anything which matched the pattern. */
683 if (*p == 0 || *p == ',')
686 while (*p && (c = *p++) != ',')
700 /* Ignore rest of this alternative. */
701 while (*p && *p != ',') p++;
710 /* This operand must be the same as a previous one.
711 This kind of constraint is used for instructions such
712 as add when they take only two operands.
714 Note that the lower-numbered operand is passed first. */
716 if (operands_match_p (operands[c - '0'],
717 operands[this_operand]))
719 operand_matches[this_operand] = c - '0';
725 /* p is used for address_operands. Since this is an asm,
726 just to make sure that the operand is valid for Pmode. */
728 if (strict_memory_address_p (Pmode, op))
733 /* Anything goes unless it is a REG and really has a hard reg
734 but the hard reg is not in the class GENERAL_REGS. */
735 if (GENERAL_REGS == ALL_REGS
736 || GET_CODE (op) != REG
737 || reg_fits_class_p (op, GENERAL_REGS, offset, mode))
739 if (GET_CODE (op) == REG)
740 operand_class[this_operand]
741 = reg_class_subunion[(int) operand_class[this_operand]][(int) GENERAL_REGS];
747 if (GET_CODE (op) == REG
748 && (GENERAL_REGS == ALL_REGS
749 || reg_fits_class_p (op, GENERAL_REGS, offset, mode)))
751 operand_class[this_operand]
752 = reg_class_subunion[(int) operand_class[this_operand]][(int) GENERAL_REGS];
758 /* This is used for a MATCH_SCRATCH in the cases when we
759 don't actually need anything. So anything goes any time. */
764 if (GET_CODE (op) == MEM)
769 if (GET_CODE (op) == MEM
770 && (GET_CODE (XEXP (op, 0)) == PRE_DEC
771 || GET_CODE (XEXP (op, 0)) == POST_DEC))
776 if (GET_CODE (op) == MEM
777 && (GET_CODE (XEXP (op, 0)) == PRE_INC
778 || GET_CODE (XEXP (op, 0)) == POST_INC))
783 /* Match any CONST_DOUBLE, but only if
784 we can examine the bits of it reliably. */
785 if ((HOST_FLOAT_FORMAT != TARGET_FLOAT_FORMAT
786 || HOST_BITS_PER_WIDE_INT != BITS_PER_WORD)
787 && GET_CODE (op) != VOIDmode && ! flag_pretend_float)
789 if (GET_CODE (op) == CONST_DOUBLE)
794 if (GET_CODE (op) == CONST_DOUBLE)
800 if (GET_CODE (op) == CONST_DOUBLE
801 && CONST_DOUBLE_OK_FOR_LETTER_P (op, c))
806 if (GET_CODE (op) == CONST_INT
807 || (GET_CODE (op) == CONST_DOUBLE
808 && GET_MODE (op) == VOIDmode))
817 if (GET_CODE (op) == CONST_INT
818 || (GET_CODE (op) == CONST_DOUBLE
819 && GET_MODE (op) == VOIDmode))
831 if (GET_CODE (op) == CONST_INT
832 && CONST_OK_FOR_LETTER_P (INTVAL (op), c))
836 #ifdef EXTRA_CONSTRAINT
842 if (EXTRA_CONSTRAINT (op, c))
848 if (GET_CODE (op) == MEM && ! offsettable_memref_p (op))
853 if (offsettable_memref_p (op))
858 if (GET_CODE (op) == REG
859 && reg_fits_class_p (op, REG_CLASS_FROM_LETTER (c),
862 operand_class[this_operand]
863 = reg_class_subunion[(int)operand_class[this_operand]][(int) REG_CLASS_FROM_LETTER (c)];
868 constraints[this_operand] = p;
869 /* If this operand did not win somehow,
870 this alternative loses. */
874 /* This alternative won; the operands are ok.
875 Change whichever operands this alternative says to change. */
882 /* For operands constrained to match another operand, copy the other
883 operand's class to this operand's class. */
884 for (j = 0; j < n_operands; j++)
885 if (operand_matches[j] >= 0)
886 operand_class[j] = operand_class[operand_matches[j]];
888 return this_alternative == n_alternatives ? -1 : this_alternative;
891 /* Record the life info of each stack reg in INSN, updating REGSTACK.
892 N_INPUTS is the number of inputs; N_OUTPUTS the outputs. CONSTRAINTS
893 is an array of the constraint strings used in the asm statement.
894 OPERANDS is an array of all operands for the insn, and is assumed to
895 contain all output operands, then all inputs operands.
897 There are many rules that an asm statement for stack-like regs must
898 follow. Those rules are explained at the top of this file: the rule
899 numbers below refer to that explanation. */
902 record_asm_reg_life (insn, regstack, operands, constraints,
908 int n_inputs, n_outputs;
911 int n_operands = n_inputs + n_outputs;
912 int first_input = n_outputs;
914 int malformed_asm = 0;
915 rtx body = PATTERN (insn);
917 int *operand_matches = (int *) alloca (n_operands * sizeof (int *));
919 enum reg_class *operand_class
920 = (enum reg_class *) alloca (n_operands * sizeof (enum reg_class *));
922 int reg_used_as_output[FIRST_PSEUDO_REGISTER];
923 int implicitly_dies[FIRST_PSEUDO_REGISTER];
927 /* Find out what the constraints require. If no constraint
928 alternative matches, this asm is malformed. */
929 i = constrain_asm_operands (n_operands, operands, constraints,
930 operand_matches, operand_class);
934 /* Strip SUBREGs here to make the following code simpler. */
935 for (i = 0; i < n_operands; i++)
936 if (GET_CODE (operands[i]) == SUBREG
937 && GET_CODE (SUBREG_REG (operands[i])) == REG)
938 operands[i] = SUBREG_REG (operands[i]);
940 /* Set up CLOBBER_REG. */
944 if (GET_CODE (body) == PARALLEL)
946 clobber_reg = (rtx *) alloca (XVECLEN (body, 0) * sizeof (rtx *));
948 for (i = 0; i < XVECLEN (body, 0); i++)
949 if (GET_CODE (XVECEXP (body, 0, i)) == CLOBBER)
951 rtx clobber = XVECEXP (body, 0, i);
952 rtx reg = XEXP (clobber, 0);
954 if (GET_CODE (reg) == SUBREG && GET_CODE (SUBREG_REG (reg)) == REG)
955 reg = SUBREG_REG (reg);
957 if (STACK_REG_P (reg))
959 clobber_reg[n_clobbers] = reg;
965 /* Enforce rule #4: Output operands must specifically indicate which
966 reg an output appears in after an asm. "=f" is not allowed: the
967 operand constraints must select a class with a single reg.
969 Also enforce rule #5: Output operands must start at the top of
970 the reg-stack: output operands may not "skip" a reg. */
972 bzero ((char *) reg_used_as_output, sizeof (reg_used_as_output));
973 for (i = 0; i < n_outputs; i++)
974 if (STACK_REG_P (operands[i]))
976 if (reg_class_size[(int) operand_class[i]] != 1)
978 error_for_asm (insn, "Output constraint %d must specify a single register", i);
982 reg_used_as_output[REGNO (operands[i])] = 1;
986 /* Search for first non-popped reg. */
987 for (i = FIRST_STACK_REG; i < LAST_STACK_REG + 1; i++)
988 if (! reg_used_as_output[i])
991 /* If there are any other popped regs, that's an error. */
992 for (; i < LAST_STACK_REG + 1; i++)
993 if (reg_used_as_output[i])
996 if (i != LAST_STACK_REG + 1)
998 error_for_asm (insn, "Output regs must be grouped at top of stack");
1002 /* Enforce rule #2: All implicitly popped input regs must be closer
1003 to the top of the reg-stack than any input that is not implicitly
1006 bzero ((char *) implicitly_dies, sizeof (implicitly_dies));
1007 for (i = first_input; i < first_input + n_inputs; i++)
1008 if (STACK_REG_P (operands[i]))
1010 /* An input reg is implicitly popped if it is tied to an
1011 output, or if there is a CLOBBER for it. */
1014 for (j = 0; j < n_clobbers; j++)
1015 if (operands_match_p (clobber_reg[j], operands[i]))
1018 if (j < n_clobbers || operand_matches[i] >= 0)
1019 implicitly_dies[REGNO (operands[i])] = 1;
1022 /* Search for first non-popped reg. */
1023 for (i = FIRST_STACK_REG; i < LAST_STACK_REG + 1; i++)
1024 if (! implicitly_dies[i])
1027 /* If there are any other popped regs, that's an error. */
1028 for (; i < LAST_STACK_REG + 1; i++)
1029 if (implicitly_dies[i])
1032 if (i != LAST_STACK_REG + 1)
1034 error_for_asm (insn,
1035 "Implicitly popped regs must be grouped at top of stack");
1039 /* Enfore rule #3: If any input operand uses the "f" constraint, all
1040 output constraints must use the "&" earlyclobber.
1042 ??? Detect this more deterministically by having constraint_asm_operands
1043 record any earlyclobber. */
1045 for (i = first_input; i < first_input + n_inputs; i++)
1046 if (operand_matches[i] == -1)
1050 for (j = 0; j < n_outputs; j++)
1051 if (operands_match_p (operands[j], operands[i]))
1053 error_for_asm (insn,
1054 "Output operand %d must use `&' constraint", j);
1061 /* Avoid further trouble with this insn. */
1062 PATTERN (insn) = gen_rtx_USE (VOIDmode, const0_rtx);
1063 PUT_MODE (insn, VOIDmode);
1067 /* Process all outputs */
1068 for (i = 0; i < n_outputs; i++)
1070 rtx op = operands[i];
1072 if (! STACK_REG_P (op))
1074 if (stack_regs_mentioned_p (op))
1080 /* Each destination is dead before this insn. If the
1081 destination is not used after this insn, record this with
1084 if (! TEST_HARD_REG_BIT (regstack->reg_set, REGNO (op)))
1085 REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_UNUSED, op,
1088 CLEAR_HARD_REG_BIT (regstack->reg_set, REGNO (op));
1091 /* Process all inputs */
1092 for (i = first_input; i < first_input + n_inputs; i++)
1094 if (! STACK_REG_P (operands[i]))
1096 if (stack_regs_mentioned_p (operands[i]))
1102 /* If an input is dead after the insn, record a death note.
1103 But don't record a death note if there is already a death note,
1104 or if the input is also an output. */
1106 if (! TEST_HARD_REG_BIT (regstack->reg_set, REGNO (operands[i]))
1107 && operand_matches[i] == -1
1108 && find_regno_note (insn, REG_DEAD, REGNO (operands[i])) == NULL_RTX)
1109 REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_DEAD, operands[i],
1112 SET_HARD_REG_BIT (regstack->reg_set, REGNO (operands[i]));
1116 /* Scan PAT, which is part of INSN, and record registers appearing in
1117 a SET_DEST in DEST, and other registers in SRC.
1119 This function does not know about SET_DESTs that are both input and
1120 output (such as ZERO_EXTRACT) - this cannot happen on a 387. */
1123 record_reg_life_pat (pat, src, dest, douse)
1125 HARD_REG_SET *src, *dest;
1131 if (STACK_REG_P (pat)
1132 || (GET_CODE (pat) == SUBREG && STACK_REG_P (SUBREG_REG (pat))))
1135 mark_regs_pat (pat, src);
1138 mark_regs_pat (pat, dest);
1143 if (GET_CODE (pat) == SET)
1145 record_reg_life_pat (XEXP (pat, 0), NULL_PTR, dest, 0);
1146 record_reg_life_pat (XEXP (pat, 1), src, NULL_PTR, 0);
1150 /* We don't need to consider either of these cases. */
1151 if ((GET_CODE (pat) == USE && !douse) || GET_CODE (pat) == CLOBBER)
1154 fmt = GET_RTX_FORMAT (GET_CODE (pat));
1155 for (i = GET_RTX_LENGTH (GET_CODE (pat)) - 1; i >= 0; i--)
1161 for (j = XVECLEN (pat, i) - 1; j >= 0; j--)
1162 record_reg_life_pat (XVECEXP (pat, i, j), src, dest, 0);
1164 else if (fmt[i] == 'e')
1165 record_reg_life_pat (XEXP (pat, i), src, dest, 0);
1169 /* Calculate the number of inputs and outputs in BODY, an
1170 asm_operands. N_OPERANDS is the total number of operands, and
1171 N_INPUTS and N_OUTPUTS are pointers to ints into which the results are
1175 get_asm_operand_lengths (body, n_operands, n_inputs, n_outputs)
1178 int *n_inputs, *n_outputs;
1180 if (GET_CODE (body) == SET && GET_CODE (SET_SRC (body)) == ASM_OPERANDS)
1181 *n_inputs = ASM_OPERANDS_INPUT_LENGTH (SET_SRC (body));
1183 else if (GET_CODE (body) == ASM_OPERANDS)
1184 *n_inputs = ASM_OPERANDS_INPUT_LENGTH (body);
1186 else if (GET_CODE (body) == PARALLEL
1187 && GET_CODE (XVECEXP (body, 0, 0)) == SET)
1188 *n_inputs = ASM_OPERANDS_INPUT_LENGTH (SET_SRC (XVECEXP (body, 0, 0)));
1190 else if (GET_CODE (body) == PARALLEL
1191 && GET_CODE (XVECEXP (body, 0, 0)) == ASM_OPERANDS)
1192 *n_inputs = ASM_OPERANDS_INPUT_LENGTH (XVECEXP (body, 0, 0));
1196 *n_outputs = n_operands - *n_inputs;
1199 /* Scan INSN, which is in BLOCK, and record the life & death of stack
1200 registers in REGSTACK. This function is called to process insns from
1201 the last insn in a block to the first. The actual scanning is done in
1202 record_reg_life_pat.
1204 If a register is live after a CALL_INSN, but is not a value return
1205 register for that CALL_INSN, then code is emitted to initialize that
1206 register. The block_end[] data is kept accurate.
1208 Existing death and unset notes for stack registers are deleted
1209 before processing the insn. */
1212 record_reg_life (insn, block, regstack)
1217 rtx note, *note_link;
1220 if ((GET_CODE (insn) != INSN && GET_CODE (insn) != CALL_INSN)
1221 || INSN_DELETED_P (insn))
1224 /* Strip death notes for stack regs from this insn */
1226 note_link = ®_NOTES(insn);
1227 for (note = *note_link; note; note = XEXP (note, 1))
1228 if (STACK_REG_P (XEXP (note, 0))
1229 && (REG_NOTE_KIND (note) == REG_DEAD
1230 || REG_NOTE_KIND (note) == REG_UNUSED))
1231 *note_link = XEXP (note, 1);
1233 note_link = &XEXP (note, 1);
1235 /* Process all patterns in the insn. */
1237 n_operands = asm_noperands (PATTERN (insn));
1238 if (n_operands >= 0)
1240 /* This insn is an `asm' with operands. Decode the operands,
1241 decide how many are inputs, and record the life information. */
1243 rtx operands[MAX_RECOG_OPERANDS];
1244 rtx body = PATTERN (insn);
1245 int n_inputs, n_outputs;
1246 char **constraints = (char **) alloca (n_operands * sizeof (char *));
1248 decode_asm_operands (body, operands, NULL_PTR, constraints, NULL_PTR);
1249 get_asm_operand_lengths (body, n_operands, &n_inputs, &n_outputs);
1250 record_asm_reg_life (insn, regstack, operands, constraints,
1251 n_inputs, n_outputs);
1256 HARD_REG_SET src, dest;
1259 CLEAR_HARD_REG_SET (src);
1260 CLEAR_HARD_REG_SET (dest);
1262 if (GET_CODE (insn) == CALL_INSN)
1263 for (note = CALL_INSN_FUNCTION_USAGE (insn);
1265 note = XEXP (note, 1))
1266 if (GET_CODE (XEXP (note, 0)) == USE)
1267 record_reg_life_pat (SET_DEST (XEXP (note, 0)), &src, NULL_PTR, 0);
1269 record_reg_life_pat (PATTERN (insn), &src, &dest, 0);
1270 for (regno = FIRST_STACK_REG; regno <= LAST_STACK_REG; regno++)
1271 if (! TEST_HARD_REG_BIT (regstack->reg_set, regno))
1273 if (TEST_HARD_REG_BIT (src, regno)
1274 && ! TEST_HARD_REG_BIT (dest, regno))
1275 REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_DEAD,
1276 FP_MODE_REG (regno, DFmode),
1278 else if (TEST_HARD_REG_BIT (dest, regno))
1279 REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_UNUSED,
1280 FP_MODE_REG (regno, DFmode),
1284 if (GET_CODE (insn) == CALL_INSN)
1288 /* There might be a reg that is live after a function call.
1289 Initialize it to zero so that the program does not crash. See
1290 comment towards the end of stack_reg_life_analysis(). */
1292 for (reg = FIRST_STACK_REG; reg <= LAST_STACK_REG; reg++)
1293 if (! TEST_HARD_REG_BIT (dest, reg)
1294 && TEST_HARD_REG_BIT (regstack->reg_set, reg))
1298 /* The insn will use virtual register numbers, and so
1299 convert_regs is expected to process these. But BLOCK_NUM
1300 cannot be used on these insns, because they do not appear in
1303 pat = gen_rtx_SET (VOIDmode, FP_MODE_REG (reg, DFmode),
1304 CONST0_RTX (DFmode));
1305 init = emit_insn_after (pat, insn);
1306 PUT_MODE (init, QImode);
1308 CLEAR_HARD_REG_BIT (regstack->reg_set, reg);
1310 /* If the CALL_INSN was the end of a block, move the
1311 block_end to point to the new insn. */
1313 if (block_end[block] == insn)
1314 block_end[block] = init;
1317 /* Some regs do not survive a CALL */
1318 AND_COMPL_HARD_REG_SET (regstack->reg_set, call_used_reg_set);
1321 AND_COMPL_HARD_REG_SET (regstack->reg_set, dest);
1322 IOR_HARD_REG_SET (regstack->reg_set, src);
1326 /* Find all basic blocks of the function, which starts with FIRST.
1327 For each JUMP_INSN, build the chain of LABEL_REFS on each CODE_LABEL. */
1335 register RTX_CODE prev_code = BARRIER;
1336 register RTX_CODE code;
1337 rtx label_value_list = 0;
1339 /* Record where all the blocks start and end.
1340 Record which basic blocks control can drop in to. */
1343 for (insn = first; insn; insn = NEXT_INSN (insn))
1345 /* Note that this loop must select the same block boundaries
1346 as code in reg_to_stack, but that these are not the same
1347 as those selected in flow.c. */
1349 code = GET_CODE (insn);
1351 if (code == CODE_LABEL
1352 || (prev_code != INSN
1353 && prev_code != CALL_INSN
1354 && prev_code != CODE_LABEL
1355 && GET_RTX_CLASS (code) == 'i'))
1357 block_begin[++block] = insn;
1358 block_end[block] = insn;
1359 block_drops_in[block] = prev_code != BARRIER;
1361 else if (GET_RTX_CLASS (code) == 'i')
1362 block_end[block] = insn;
1364 if (GET_RTX_CLASS (code) == 'i')
1368 /* Make a list of all labels referred to other than by jumps. */
1369 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
1370 if (REG_NOTE_KIND (note) == REG_LABEL)
1371 label_value_list = gen_rtx_EXPR_LIST (VOIDmode, XEXP (note, 0),
1375 block_number[INSN_UID (insn)] = block;
1381 if (block + 1 != blocks)
1384 /* generate all label references to the corresponding jump insn */
1385 for (block = 0; block < blocks; block++)
1387 insn = block_end[block];
1389 if (GET_CODE (insn) == JUMP_INSN)
1391 rtx pat = PATTERN (insn);
1394 if (computed_jump_p (insn))
1396 for (x = label_value_list; x; x = XEXP (x, 1))
1397 record_label_references (insn,
1398 gen_rtx_LABEL_REF (VOIDmode,
1401 for (x = forced_labels; x; x = XEXP (x, 1))
1402 record_label_references (insn,
1403 gen_rtx_LABEL_REF (VOIDmode,
1407 record_label_references (insn, pat);
1412 /* If current function returns its result in an fp stack register,
1413 return the REG. Otherwise, return 0. */
1419 rtx result = DECL_RTL (DECL_RESULT (decl));
1422 && ! (GET_CODE (result) == REG
1423 && REGNO (result) < FIRST_PSEUDO_REGISTER))
1425 #ifdef FUNCTION_OUTGOING_VALUE
1427 = FUNCTION_OUTGOING_VALUE (TREE_TYPE (DECL_RESULT (decl)), decl);
1429 result = FUNCTION_VALUE (TREE_TYPE (DECL_RESULT (decl)), decl);
1433 return result != 0 && STACK_REG_P (result) ? result : 0;
1436 /* Determine the which registers are live at the start of each basic
1437 block of the function whose first insn is FIRST.
1439 First, if the function returns a real_type, mark the function
1440 return type as live at each return point, as the RTL may not give any
1441 hint that the register is live.
1443 Then, start with the last block and work back to the first block.
1444 Similarly, work backwards within each block, insn by insn, recording
1445 which regs are dead and which are used (and therefore live) in the
1446 hard reg set of block_stack_in[].
1448 After processing each basic block, if there is a label at the start
1449 of the block, propagate the live registers to all jumps to this block.
1451 As a special case, if there are regs live in this block, that are
1452 not live in a block containing a jump to this label, and the block
1453 containing the jump has already been processed, we must propagate this
1454 block's entry register life back to the block containing the jump, and
1455 restart life analysis from there.
1457 In the worst case, this function may traverse the insns
1458 REG_STACK_SIZE times. This is necessary, since a jump towards the end
1459 of the insns may not know that a reg is live at a target that is early
1460 in the insns. So we back up and start over with the new reg live.
1462 If there are registers that are live at the start of the function,
1463 insns are emitted to initialize these registers. Something similar is
1464 done after CALL_INSNs in record_reg_life. */
1467 stack_reg_life_analysis (first, stackentry)
1469 HARD_REG_SET *stackentry;
1472 struct stack_def regstack;
1477 if ((retvalue = stack_result (current_function_decl)))
1479 /* Find all RETURN insns and mark them. */
1481 for (block = blocks - 1; --block >= 0;)
1482 if (GET_CODE (block_end[block]) == JUMP_INSN
1483 && GET_CODE (PATTERN (block_end[block])) == RETURN)
1484 mark_regs_pat (retvalue, block_out_reg_set+block);
1486 /* Mark off the end of last block if we "fall off" the end of the
1487 function into the epilogue. */
1489 if (GET_CODE (block_end[blocks-1]) != JUMP_INSN
1490 || GET_CODE (PATTERN (block_end[blocks-1])) == RETURN)
1491 mark_regs_pat (retvalue, block_out_reg_set+blocks-1);
1495 /* now scan all blocks backward for stack register use */
1500 register rtx insn, prev;
1502 /* current register status at last instruction */
1504 COPY_HARD_REG_SET (regstack.reg_set, block_out_reg_set[block]);
1506 prev = block_end[block];
1510 prev = PREV_INSN (insn);
1512 /* If the insn is a CALL_INSN, we need to ensure that
1513 everything dies. But otherwise don't process unless there
1514 are some stack regs present. */
1516 if (GET_MODE (insn) == QImode || GET_CODE (insn) == CALL_INSN)
1517 record_reg_life (insn, block, ®stack);
1519 } while (insn != block_begin[block]);
1521 /* Set the state at the start of the block. Mark that no
1522 register mapping information known yet. */
1524 COPY_HARD_REG_SET (block_stack_in[block].reg_set, regstack.reg_set);
1525 block_stack_in[block].top = -2;
1527 /* If there is a label, propagate our register life to all jumps
1530 if (GET_CODE (insn) == CODE_LABEL)
1533 int must_restart = 0;
1535 for (label = LABEL_REFS (insn); label != insn;
1536 label = LABEL_NEXTREF (label))
1538 int jump_block = BLOCK_NUM (CONTAINING_INSN (label));
1540 if (jump_block < block)
1541 IOR_HARD_REG_SET (block_out_reg_set[jump_block],
1542 block_stack_in[block].reg_set);
1545 /* The block containing the jump has already been
1546 processed. If there are registers that were not known
1547 to be live then, but are live now, we must back up
1548 and restart life analysis from that point with the new
1549 life information. */
1551 GO_IF_HARD_REG_SUBSET (block_stack_in[block].reg_set,
1552 block_out_reg_set[jump_block],
1555 IOR_HARD_REG_SET (block_out_reg_set[jump_block],
1556 block_stack_in[block].reg_set);
1570 if (block_drops_in[block])
1571 IOR_HARD_REG_SET (block_out_reg_set[block-1],
1572 block_stack_in[block].reg_set);
1577 /* If any reg is live at the start of the first block of a
1578 function, then we must guarantee that the reg holds some value by
1579 generating our own "load" of that register. Otherwise a 387 would
1580 fault trying to access an empty register. */
1582 /* Load zero into each live register. The fact that a register
1583 appears live at the function start necessarily implies an error
1584 in the user program: it means that (unless the offending code is *never*
1585 executed) this program is using uninitialised floating point
1586 variables. In order to keep broken code like this happy, we initialise
1587 those variables with zero.
1589 Note that we are inserting virtual register references here:
1590 these insns must be processed by convert_regs later. Also, these
1591 insns will not be in block_number, so BLOCK_NUM() will fail for them. */
1593 for (reg = LAST_STACK_REG; reg >= FIRST_STACK_REG; reg--)
1594 if (TEST_HARD_REG_BIT (block_stack_in[0].reg_set, reg)
1595 && ! TEST_HARD_REG_BIT (*stackentry, reg))
1599 init_rtx = gen_rtx_SET (VOIDmode, FP_MODE_REG(reg, DFmode),
1600 CONST0_RTX (DFmode));
1601 block_begin[0] = emit_insn_after (init_rtx, first);
1602 PUT_MODE (block_begin[0], QImode);
1604 CLEAR_HARD_REG_BIT (block_stack_in[0].reg_set, reg);
1608 /*****************************************************************************
1609 This section deals with stack register substitution, and forms the second
1611 *****************************************************************************/
1613 /* Replace REG, which is a pointer to a stack reg RTX, with an RTX for
1614 the desired hard REGNO. */
1617 replace_reg (reg, regno)
1621 if (regno < FIRST_STACK_REG || regno > LAST_STACK_REG
1622 || ! STACK_REG_P (*reg))
1625 switch (GET_MODE_CLASS (GET_MODE (*reg)))
1629 case MODE_COMPLEX_FLOAT:;
1632 *reg = FP_MODE_REG (regno, GET_MODE (*reg));
1635 /* Remove a note of type NOTE, which must be found, for register
1636 number REGNO from INSN. Remove only one such note. */
1639 remove_regno_note (insn, note, regno)
1644 register rtx *note_link, this;
1646 note_link = ®_NOTES(insn);
1647 for (this = *note_link; this; this = XEXP (this, 1))
1648 if (REG_NOTE_KIND (this) == note
1649 && REG_P (XEXP (this, 0)) && REGNO (XEXP (this, 0)) == regno)
1651 *note_link = XEXP (this, 1);
1655 note_link = &XEXP (this, 1);
1660 /* Find the hard register number of virtual register REG in REGSTACK.
1661 The hard register number is relative to the top of the stack. -1 is
1662 returned if the register is not found. */
1665 get_hard_regnum (regstack, reg)
1671 if (! STACK_REG_P (reg))
1674 for (i = regstack->top; i >= 0; i--)
1675 if (regstack->reg[i] == REGNO (reg))
1678 return i >= 0 ? (FIRST_STACK_REG + regstack->top - i) : -1;
1681 /* Delete INSN from the RTL. Mark the insn, but don't remove it from
1682 the chain of insns. Doing so could confuse block_begin and block_end
1683 if this were the only insn in the block. */
1686 delete_insn_for_stacker (insn)
1689 PUT_CODE (insn, NOTE);
1690 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
1691 NOTE_SOURCE_FILE (insn) = 0;
1694 /* Emit an insn to pop virtual register REG before or after INSN.
1695 REGSTACK is the stack state after INSN and is updated to reflect this
1696 pop. WHEN is either emit_insn_before or emit_insn_after. A pop insn
1697 is represented as a SET whose destination is the register to be popped
1698 and source is the top of stack. A death note for the top of stack
1699 cases the movdf pattern to pop. */
1702 emit_pop_insn (insn, regstack, reg, when)
1708 rtx pop_insn, pop_rtx;
1711 hard_regno = get_hard_regnum (regstack, reg);
1713 if (hard_regno < FIRST_STACK_REG)
1716 pop_rtx = gen_rtx_SET (VOIDmode, FP_MODE_REG (hard_regno, DFmode),
1717 FP_MODE_REG (FIRST_STACK_REG, DFmode));
1719 pop_insn = (*when) (pop_rtx, insn);
1720 /* ??? This used to be VOIDmode, but that seems wrong. */
1721 PUT_MODE (pop_insn, QImode);
1723 REG_NOTES (pop_insn) = gen_rtx_EXPR_LIST (REG_DEAD,
1724 FP_MODE_REG (FIRST_STACK_REG, DFmode),
1725 REG_NOTES (pop_insn));
1727 regstack->reg[regstack->top - (hard_regno - FIRST_STACK_REG)]
1728 = regstack->reg[regstack->top];
1730 CLEAR_HARD_REG_BIT (regstack->reg_set, REGNO (reg));
1735 /* Emit an insn before or after INSN to swap virtual register REG with the
1736 top of stack. WHEN should be `emit_insn_before' or `emit_insn_before'
1737 REGSTACK is the stack state before the swap, and is updated to reflect
1738 the swap. A swap insn is represented as a PARALLEL of two patterns:
1739 each pattern moves one reg to the other.
1741 If REG is already at the top of the stack, no insn is emitted. */
1744 emit_swap_insn (insn, regstack, reg)
1751 rtx swap_rtx, swap_insn;
1752 int tmp, other_reg; /* swap regno temps */
1753 rtx i1; /* the stack-reg insn prior to INSN */
1754 rtx i1set = NULL_RTX; /* the SET rtx within I1 */
1756 hard_regno = get_hard_regnum (regstack, reg);
1758 if (hard_regno < FIRST_STACK_REG)
1760 if (hard_regno == FIRST_STACK_REG)
1763 other_reg = regstack->top - (hard_regno - FIRST_STACK_REG);
1765 tmp = regstack->reg[other_reg];
1766 regstack->reg[other_reg] = regstack->reg[regstack->top];
1767 regstack->reg[regstack->top] = tmp;
1769 /* Find the previous insn involving stack regs, but don't go past
1770 any labels, calls or jumps. */
1771 i1 = prev_nonnote_insn (insn);
1772 while (i1 && GET_CODE (i1) == INSN && GET_MODE (i1) != QImode)
1773 i1 = prev_nonnote_insn (i1);
1776 i1set = single_set (i1);
1780 rtx i1src = *get_true_reg (&SET_SRC (i1set));
1781 rtx i1dest = *get_true_reg (&SET_DEST (i1set));
1783 /* If the previous register stack push was from the reg we are to
1784 swap with, omit the swap. */
1786 if (GET_CODE (i1dest) == REG && REGNO (i1dest) == FIRST_STACK_REG
1787 && GET_CODE (i1src) == REG && REGNO (i1src) == hard_regno - 1
1788 && find_regno_note (i1, REG_DEAD, FIRST_STACK_REG) == NULL_RTX)
1791 /* If the previous insn wrote to the reg we are to swap with,
1794 if (GET_CODE (i1dest) == REG && REGNO (i1dest) == hard_regno
1795 && GET_CODE (i1src) == REG && REGNO (i1src) == FIRST_STACK_REG
1796 && find_regno_note (i1, REG_DEAD, FIRST_STACK_REG) == NULL_RTX)
1800 if (GET_RTX_CLASS (GET_CODE (i1)) == 'i' && sets_cc0_p (PATTERN (i1)))
1802 i1 = next_nonnote_insn (i1);
1807 swap_rtx = gen_swapdf (FP_MODE_REG (hard_regno, DFmode),
1808 FP_MODE_REG (FIRST_STACK_REG, DFmode));
1809 swap_insn = emit_insn_after (swap_rtx, i1);
1810 /* ??? This used to be VOIDmode, but that seems wrong. */
1811 PUT_MODE (swap_insn, QImode);
1814 /* Handle a move to or from a stack register in PAT, which is in INSN.
1815 REGSTACK is the current stack. */
1818 move_for_stack_reg (insn, regstack, pat)
1823 rtx *psrc = get_true_reg (&SET_SRC (pat));
1824 rtx *pdest = get_true_reg (&SET_DEST (pat));
1828 src = *psrc; dest = *pdest;
1830 if (STACK_REG_P (src) && STACK_REG_P (dest))
1832 /* Write from one stack reg to another. If SRC dies here, then
1833 just change the register mapping and delete the insn. */
1835 note = find_regno_note (insn, REG_DEAD, REGNO (src));
1840 /* If this is a no-op move, there must not be a REG_DEAD note. */
1841 if (REGNO (src) == REGNO (dest))
1844 for (i = regstack->top; i >= 0; i--)
1845 if (regstack->reg[i] == REGNO (src))
1848 /* The source must be live, and the dest must be dead. */
1849 if (i < 0 || get_hard_regnum (regstack, dest) >= FIRST_STACK_REG)
1852 /* It is possible that the dest is unused after this insn.
1853 If so, just pop the src. */
1855 if (find_regno_note (insn, REG_UNUSED, REGNO (dest)))
1857 emit_pop_insn (insn, regstack, src, emit_insn_after);
1859 delete_insn_for_stacker (insn);
1863 regstack->reg[i] = REGNO (dest);
1865 SET_HARD_REG_BIT (regstack->reg_set, REGNO (dest));
1866 CLEAR_HARD_REG_BIT (regstack->reg_set, REGNO (src));
1868 delete_insn_for_stacker (insn);
1873 /* The source reg does not die. */
1875 /* If this appears to be a no-op move, delete it, or else it
1876 will confuse the machine description output patterns. But if
1877 it is REG_UNUSED, we must pop the reg now, as per-insn processing
1878 for REG_UNUSED will not work for deleted insns. */
1880 if (REGNO (src) == REGNO (dest))
1882 if (find_regno_note (insn, REG_UNUSED, REGNO (dest)))
1883 emit_pop_insn (insn, regstack, dest, emit_insn_after);
1885 delete_insn_for_stacker (insn);
1889 /* The destination ought to be dead */
1890 if (get_hard_regnum (regstack, dest) >= FIRST_STACK_REG)
1893 replace_reg (psrc, get_hard_regnum (regstack, src));
1895 regstack->reg[++regstack->top] = REGNO (dest);
1896 SET_HARD_REG_BIT (regstack->reg_set, REGNO (dest));
1897 replace_reg (pdest, FIRST_STACK_REG);
1899 else if (STACK_REG_P (src))
1901 /* Save from a stack reg to MEM, or possibly integer reg. Since
1902 only top of stack may be saved, emit an exchange first if
1905 emit_swap_insn (insn, regstack, src);
1907 note = find_regno_note (insn, REG_DEAD, REGNO (src));
1910 replace_reg (&XEXP (note, 0), FIRST_STACK_REG);
1912 CLEAR_HARD_REG_BIT (regstack->reg_set, REGNO (src));
1914 else if (GET_MODE (src) == XFmode && regstack->top < REG_STACK_SIZE - 1)
1916 /* A 387 cannot write an XFmode value to a MEM without
1917 clobbering the source reg. The output code can handle
1918 this by reading back the value from the MEM.
1919 But it is more efficient to use a temp register if one is
1920 available. Push the source value here if the register
1921 stack is not full, and then write the value to memory via
1923 rtx push_rtx, push_insn;
1924 rtx top_stack_reg = FP_MODE_REG (FIRST_STACK_REG, XFmode);
1926 push_rtx = gen_movxf (top_stack_reg, top_stack_reg);
1927 push_insn = emit_insn_before (push_rtx, insn);
1928 PUT_MODE (push_insn, QImode);
1929 REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_DEAD, top_stack_reg,
1933 replace_reg (psrc, FIRST_STACK_REG);
1935 else if (STACK_REG_P (dest))
1937 /* Load from MEM, or possibly integer REG or constant, into the
1938 stack regs. The actual target is always the top of the
1939 stack. The stack mapping is changed to reflect that DEST is
1940 now at top of stack. */
1942 /* The destination ought to be dead */
1943 if (get_hard_regnum (regstack, dest) >= FIRST_STACK_REG)
1946 if (regstack->top >= REG_STACK_SIZE)
1949 regstack->reg[++regstack->top] = REGNO (dest);
1950 SET_HARD_REG_BIT (regstack->reg_set, REGNO (dest));
1951 replace_reg (pdest, FIRST_STACK_REG);
1958 swap_rtx_condition (pat)
1964 if (GET_RTX_CLASS (GET_CODE (pat)) == '<')
1966 PUT_CODE (pat, swap_condition (GET_CODE (pat)));
1970 fmt = GET_RTX_FORMAT (GET_CODE (pat));
1971 for (i = GET_RTX_LENGTH (GET_CODE (pat)) - 1; i >= 0; i--)
1977 for (j = XVECLEN (pat, i) - 1; j >= 0; j--)
1978 swap_rtx_condition (XVECEXP (pat, i, j));
1980 else if (fmt[i] == 'e')
1981 swap_rtx_condition (XEXP (pat, i));
1985 /* Handle a comparison. Special care needs to be taken to avoid
1986 causing comparisons that a 387 cannot do correctly, such as EQ.
1988 Also, a pop insn may need to be emitted. The 387 does have an
1989 `fcompp' insn that can pop two regs, but it is sometimes too expensive
1990 to do this - a `fcomp' followed by a `fstpl %st(0)' may be easier to
1994 compare_for_stack_reg (insn, regstack, pat)
2000 rtx src1_note, src2_note;
2004 src1 = get_true_reg (&XEXP (SET_SRC (pat), 0));
2005 src2 = get_true_reg (&XEXP (SET_SRC (pat), 1));
2006 cc0_user = next_cc0_user (insn);
2008 /* If the insn that uses cc0 is an FP-conditional move, then the destination
2009 must be the top of stack */
2010 if (GET_CODE (PATTERN (cc0_user)) == SET
2011 && SET_DEST (PATTERN (cc0_user)) != pc_rtx
2012 && GET_CODE (SET_SRC (PATTERN (cc0_user))) == IF_THEN_ELSE
2013 && (GET_MODE_CLASS (GET_MODE (SET_DEST (PATTERN (cc0_user))))
2018 dest = get_true_reg (&SET_DEST (PATTERN (cc0_user)));
2021 if (get_hard_regnum (regstack, *dest) >= FIRST_STACK_REG
2022 && REGNO (*dest) != regstack->reg[regstack->top])
2024 emit_swap_insn (insn, regstack, *dest);
2030 /* ??? If fxch turns out to be cheaper than fstp, give priority to
2031 registers that die in this insn - move those to stack top first. */
2032 if (! STACK_REG_P (*src1)
2033 || (STACK_REG_P (*src2)
2034 && get_hard_regnum (regstack, *src2) == FIRST_STACK_REG))
2038 temp = XEXP (SET_SRC (pat), 0);
2039 XEXP (SET_SRC (pat), 0) = XEXP (SET_SRC (pat), 1);
2040 XEXP (SET_SRC (pat), 1) = temp;
2042 src1 = get_true_reg (&XEXP (SET_SRC (pat), 0));
2043 src2 = get_true_reg (&XEXP (SET_SRC (pat), 1));
2045 next = next_cc0_user (insn);
2046 if (next == NULL_RTX)
2049 swap_rtx_condition (PATTERN (next));
2050 INSN_CODE (next) = -1;
2051 INSN_CODE (insn) = -1;
2054 /* We will fix any death note later. */
2056 src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
2058 if (STACK_REG_P (*src2))
2059 src2_note = find_regno_note (insn, REG_DEAD, REGNO (*src2));
2061 src2_note = NULL_RTX;
2064 emit_swap_insn (insn, regstack, *src1);
2066 replace_reg (src1, FIRST_STACK_REG);
2068 if (STACK_REG_P (*src2))
2069 replace_reg (src2, get_hard_regnum (regstack, *src2));
2073 pop_stack (regstack, REGNO (XEXP (src1_note, 0)));
2074 replace_reg (&XEXP (src1_note, 0), FIRST_STACK_REG);
2077 /* If the second operand dies, handle that. But if the operands are
2078 the same stack register, don't bother, because only one death is
2079 needed, and it was just handled. */
2082 && ! (STACK_REG_P (*src1) && STACK_REG_P (*src2)
2083 && REGNO (*src1) == REGNO (*src2)))
2085 /* As a special case, two regs may die in this insn if src2 is
2086 next to top of stack and the top of stack also dies. Since
2087 we have already popped src1, "next to top of stack" is really
2088 at top (FIRST_STACK_REG) now. */
2090 if (get_hard_regnum (regstack, XEXP (src2_note, 0)) == FIRST_STACK_REG
2093 pop_stack (regstack, REGNO (XEXP (src2_note, 0)));
2094 replace_reg (&XEXP (src2_note, 0), FIRST_STACK_REG + 1);
2098 /* The 386 can only represent death of the first operand in
2099 the case handled above. In all other cases, emit a separate
2100 pop and remove the death note from here. */
2102 link_cc0_insns (insn);
2104 remove_regno_note (insn, REG_DEAD, REGNO (XEXP (src2_note, 0)));
2106 emit_pop_insn (insn, regstack, XEXP (src2_note, 0),
2112 /* Substitute new registers in PAT, which is part of INSN. REGSTACK
2113 is the current register layout. */
2116 subst_stack_regs_pat (insn, regstack, pat)
2122 rtx *src1 = (rtx *) NULL_PTR, *src2;
2123 rtx src1_note, src2_note;
2125 if (GET_CODE (pat) != SET)
2128 dest = get_true_reg (&SET_DEST (pat));
2129 src = get_true_reg (&SET_SRC (pat));
2131 /* See if this is a `movM' pattern, and handle elsewhere if so. */
2133 if (*dest != cc0_rtx
2134 && (STACK_REG_P (*src)
2135 || (STACK_REG_P (*dest)
2136 && (GET_CODE (*src) == REG || GET_CODE (*src) == MEM
2137 || GET_CODE (*src) == CONST_DOUBLE))))
2138 move_for_stack_reg (insn, regstack, pat);
2140 switch (GET_CODE (SET_SRC (pat)))
2143 compare_for_stack_reg (insn, regstack, pat);
2149 for (count = HARD_REGNO_NREGS (REGNO (*dest), GET_MODE (*dest));
2152 regstack->reg[++regstack->top] = REGNO (*dest) + count;
2153 SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest) + count);
2156 replace_reg (dest, FIRST_STACK_REG);
2160 /* This is a `tstM2' case. */
2161 if (*dest != cc0_rtx)
2168 case FLOAT_TRUNCATE:
2172 /* These insns only operate on the top of the stack. DEST might
2173 be cc0_rtx if we're processing a tstM pattern. Also, it's
2174 possible that the tstM case results in a REG_DEAD note on the
2178 src1 = get_true_reg (&XEXP (SET_SRC (pat), 0));
2180 emit_swap_insn (insn, regstack, *src1);
2182 src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
2184 if (STACK_REG_P (*dest))
2185 replace_reg (dest, FIRST_STACK_REG);
2189 replace_reg (&XEXP (src1_note, 0), FIRST_STACK_REG);
2191 CLEAR_HARD_REG_BIT (regstack->reg_set, REGNO (*src1));
2194 replace_reg (src1, FIRST_STACK_REG);
2200 /* On i386, reversed forms of subM3 and divM3 exist for
2201 MODE_FLOAT, so the same code that works for addM3 and mulM3
2205 /* These insns can accept the top of stack as a destination
2206 from a stack reg or mem, or can use the top of stack as a
2207 source and some other stack register (possibly top of stack)
2208 as a destination. */
2210 src1 = get_true_reg (&XEXP (SET_SRC (pat), 0));
2211 src2 = get_true_reg (&XEXP (SET_SRC (pat), 1));
2213 /* We will fix any death note later. */
2215 if (STACK_REG_P (*src1))
2216 src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
2218 src1_note = NULL_RTX;
2219 if (STACK_REG_P (*src2))
2220 src2_note = find_regno_note (insn, REG_DEAD, REGNO (*src2));
2222 src2_note = NULL_RTX;
2224 /* If either operand is not a stack register, then the dest
2225 must be top of stack. */
2227 if (! STACK_REG_P (*src1) || ! STACK_REG_P (*src2))
2228 emit_swap_insn (insn, regstack, *dest);
2231 /* Both operands are REG. If neither operand is already
2232 at the top of stack, choose to make the one that is the dest
2233 the new top of stack. */
2235 int src1_hard_regnum, src2_hard_regnum;
2237 src1_hard_regnum = get_hard_regnum (regstack, *src1);
2238 src2_hard_regnum = get_hard_regnum (regstack, *src2);
2239 if (src1_hard_regnum == -1 || src2_hard_regnum == -1)
2242 if (src1_hard_regnum != FIRST_STACK_REG
2243 && src2_hard_regnum != FIRST_STACK_REG)
2244 emit_swap_insn (insn, regstack, *dest);
2247 if (STACK_REG_P (*src1))
2248 replace_reg (src1, get_hard_regnum (regstack, *src1));
2249 if (STACK_REG_P (*src2))
2250 replace_reg (src2, get_hard_regnum (regstack, *src2));
2254 /* If the register that dies is at the top of stack, then
2255 the destination is somewhere else - merely substitute it.
2256 But if the reg that dies is not at top of stack, then
2257 move the top of stack to the dead reg, as though we had
2258 done the insn and then a store-with-pop. */
2260 if (REGNO (XEXP (src1_note, 0)) == regstack->reg[regstack->top])
2262 SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
2263 replace_reg (dest, get_hard_regnum (regstack, *dest));
2267 int regno = get_hard_regnum (regstack, XEXP (src1_note, 0));
2269 SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
2270 replace_reg (dest, regno);
2272 regstack->reg[regstack->top - (regno - FIRST_STACK_REG)]
2273 = regstack->reg[regstack->top];
2276 CLEAR_HARD_REG_BIT (regstack->reg_set,
2277 REGNO (XEXP (src1_note, 0)));
2278 replace_reg (&XEXP (src1_note, 0), FIRST_STACK_REG);
2283 if (REGNO (XEXP (src2_note, 0)) == regstack->reg[regstack->top])
2285 SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
2286 replace_reg (dest, get_hard_regnum (regstack, *dest));
2290 int regno = get_hard_regnum (regstack, XEXP (src2_note, 0));
2292 SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
2293 replace_reg (dest, regno);
2295 regstack->reg[regstack->top - (regno - FIRST_STACK_REG)]
2296 = regstack->reg[regstack->top];
2299 CLEAR_HARD_REG_BIT (regstack->reg_set,
2300 REGNO (XEXP (src2_note, 0)));
2301 replace_reg (&XEXP (src2_note, 0), FIRST_STACK_REG);
2306 SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
2307 replace_reg (dest, get_hard_regnum (regstack, *dest));
2313 switch (XINT (SET_SRC (pat), 1))
2317 /* These insns only operate on the top of the stack. */
2319 src1 = get_true_reg (&XVECEXP (SET_SRC (pat), 0, 0));
2321 emit_swap_insn (insn, regstack, *src1);
2323 src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
2325 if (STACK_REG_P (*dest))
2326 replace_reg (dest, FIRST_STACK_REG);
2330 replace_reg (&XEXP (src1_note, 0), FIRST_STACK_REG);
2332 CLEAR_HARD_REG_BIT (regstack->reg_set, REGNO (*src1));
2335 replace_reg (src1, FIRST_STACK_REG);
2345 /* This insn requires the top of stack to be the destination. */
2347 /* If the comparison operator is an FP comparison operator,
2348 it is handled correctly by compare_for_stack_reg () who
2349 will move the destination to the top of stack. But if the
2350 comparison operator is not an FP comparison operator, we
2351 have to handle it here. */
2352 if (get_hard_regnum (regstack, *dest) >= FIRST_STACK_REG
2353 && REGNO (*dest) != regstack->reg[regstack->top])
2354 emit_swap_insn (insn, regstack, *dest);
2356 src1 = get_true_reg (&XEXP (SET_SRC (pat), 1));
2357 src2 = get_true_reg (&XEXP (SET_SRC (pat), 2));
2359 src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
2360 src2_note = find_regno_note (insn, REG_DEAD, REGNO (*src2));
2367 src_note[1] = src1_note;
2368 src_note[2] = src2_note;
2370 if (STACK_REG_P (*src1))
2371 replace_reg (src1, get_hard_regnum (regstack, *src1));
2372 if (STACK_REG_P (*src2))
2373 replace_reg (src2, get_hard_regnum (regstack, *src2));
2375 for (i = 1; i <= 2; i++)
2378 /* If the register that dies is not at the top of stack, then
2379 move the top of stack to the dead reg */
2380 if (REGNO (XEXP (src_note[i], 0))
2381 != regstack->reg[regstack->top])
2383 remove_regno_note (insn, REG_DEAD,
2384 REGNO (XEXP (src_note [i], 0)));
2385 emit_pop_insn (insn, regstack, XEXP (src_note[i], 0),
2390 CLEAR_HARD_REG_BIT (regstack->reg_set,
2391 REGNO (XEXP (src_note[i], 0)));
2392 replace_reg (&XEXP (src_note[i], 0), FIRST_STACK_REG);
2398 /* Make dest the top of stack. Add dest to regstack if not present. */
2399 if (get_hard_regnum (regstack, *dest) < FIRST_STACK_REG)
2400 regstack->reg[++regstack->top] = REGNO (*dest);
2401 SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
2402 replace_reg (dest, FIRST_STACK_REG);
2411 /* Substitute hard regnums for any stack regs in INSN, which has
2412 N_INPUTS inputs and N_OUTPUTS outputs. REGSTACK is the stack info
2413 before the insn, and is updated with changes made here. CONSTRAINTS is
2414 an array of the constraint strings used in the asm statement.
2416 OPERANDS is an array of the operands, and OPERANDS_LOC is a
2417 parallel array of where the operands were found. The output operands
2418 all precede the input operands.
2420 There are several requirements and assumptions about the use of
2421 stack-like regs in asm statements. These rules are enforced by
2422 record_asm_stack_regs; see comments there for details. Any
2423 asm_operands left in the RTL at this point may be assume to meet the
2424 requirements, since record_asm_stack_regs removes any problem asm. */
2427 subst_asm_stack_regs (insn, regstack, operands, operands_loc, constraints,
2428 n_inputs, n_outputs)
2431 rtx *operands, **operands_loc;
2433 int n_inputs, n_outputs;
2435 int n_operands = n_inputs + n_outputs;
2436 int first_input = n_outputs;
2437 rtx body = PATTERN (insn);
2439 int *operand_matches = (int *) alloca (n_operands * sizeof (int *));
2440 enum reg_class *operand_class
2441 = (enum reg_class *) alloca (n_operands * sizeof (enum reg_class *));
2443 rtx *note_reg; /* Array of note contents */
2444 rtx **note_loc; /* Address of REG field of each note */
2445 enum reg_note *note_kind; /* The type of each note */
2450 struct stack_def temp_stack;
2456 /* Find out what the constraints required. If no constraint
2457 alternative matches, that is a compiler bug: we should have caught
2458 such an insn during the life analysis pass (and reload should have
2459 caught it regardless). */
2461 i = constrain_asm_operands (n_operands, operands, constraints,
2462 operand_matches, operand_class);
2466 /* Strip SUBREGs here to make the following code simpler. */
2467 for (i = 0; i < n_operands; i++)
2468 if (GET_CODE (operands[i]) == SUBREG
2469 && GET_CODE (SUBREG_REG (operands[i])) == REG)
2471 operands_loc[i] = & SUBREG_REG (operands[i]);
2472 operands[i] = SUBREG_REG (operands[i]);
2475 /* Set up NOTE_REG, NOTE_LOC and NOTE_KIND. */
2477 for (i = 0, note = REG_NOTES (insn); note; note = XEXP (note, 1))
2480 note_reg = (rtx *) alloca (i * sizeof (rtx));
2481 note_loc = (rtx **) alloca (i * sizeof (rtx *));
2482 note_kind = (enum reg_note *) alloca (i * sizeof (enum reg_note));
2485 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
2487 rtx reg = XEXP (note, 0);
2488 rtx *loc = & XEXP (note, 0);
2490 if (GET_CODE (reg) == SUBREG && GET_CODE (SUBREG_REG (reg)) == REG)
2492 loc = & SUBREG_REG (reg);
2493 reg = SUBREG_REG (reg);
2496 if (STACK_REG_P (reg)
2497 && (REG_NOTE_KIND (note) == REG_DEAD
2498 || REG_NOTE_KIND (note) == REG_UNUSED))
2500 note_reg[n_notes] = reg;
2501 note_loc[n_notes] = loc;
2502 note_kind[n_notes] = REG_NOTE_KIND (note);
2507 /* Set up CLOBBER_REG and CLOBBER_LOC. */
2511 if (GET_CODE (body) == PARALLEL)
2513 clobber_reg = (rtx *) alloca (XVECLEN (body, 0) * sizeof (rtx *));
2514 clobber_loc = (rtx **) alloca (XVECLEN (body, 0) * sizeof (rtx **));
2516 for (i = 0; i < XVECLEN (body, 0); i++)
2517 if (GET_CODE (XVECEXP (body, 0, i)) == CLOBBER)
2519 rtx clobber = XVECEXP (body, 0, i);
2520 rtx reg = XEXP (clobber, 0);
2521 rtx *loc = & XEXP (clobber, 0);
2523 if (GET_CODE (reg) == SUBREG && GET_CODE (SUBREG_REG (reg)) == REG)
2525 loc = & SUBREG_REG (reg);
2526 reg = SUBREG_REG (reg);
2529 if (STACK_REG_P (reg))
2531 clobber_reg[n_clobbers] = reg;
2532 clobber_loc[n_clobbers] = loc;
2538 bcopy ((char *) regstack, (char *) &temp_stack, sizeof (temp_stack));
2540 /* Put the input regs into the desired place in TEMP_STACK. */
2542 for (i = first_input; i < first_input + n_inputs; i++)
2543 if (STACK_REG_P (operands[i])
2544 && reg_class_subset_p (operand_class[i], FLOAT_REGS)
2545 && operand_class[i] != FLOAT_REGS)
2547 /* If an operand needs to be in a particular reg in
2548 FLOAT_REGS, the constraint was either 't' or 'u'. Since
2549 these constraints are for single register classes, and reload
2550 guaranteed that operand[i] is already in that class, we can
2551 just use REGNO (operands[i]) to know which actual reg this
2552 operand needs to be in. */
2554 int regno = get_hard_regnum (&temp_stack, operands[i]);
2559 if (regno != REGNO (operands[i]))
2561 /* operands[i] is not in the right place. Find it
2562 and swap it with whatever is already in I's place.
2563 K is where operands[i] is now. J is where it should
2567 k = temp_stack.top - (regno - FIRST_STACK_REG);
2569 - (REGNO (operands[i]) - FIRST_STACK_REG));
2571 temp = temp_stack.reg[k];
2572 temp_stack.reg[k] = temp_stack.reg[j];
2573 temp_stack.reg[j] = temp;
2577 /* emit insns before INSN to make sure the reg-stack is in the right
2580 change_stack (insn, regstack, &temp_stack, emit_insn_before);
2582 /* Make the needed input register substitutions. Do death notes and
2583 clobbers too, because these are for inputs, not outputs. */
2585 for (i = first_input; i < first_input + n_inputs; i++)
2586 if (STACK_REG_P (operands[i]))
2588 int regnum = get_hard_regnum (regstack, operands[i]);
2593 replace_reg (operands_loc[i], regnum);
2596 for (i = 0; i < n_notes; i++)
2597 if (note_kind[i] == REG_DEAD)
2599 int regnum = get_hard_regnum (regstack, note_reg[i]);
2604 replace_reg (note_loc[i], regnum);
2607 for (i = 0; i < n_clobbers; i++)
2609 /* It's OK for a CLOBBER to reference a reg that is not live.
2610 Don't try to replace it in that case. */
2611 int regnum = get_hard_regnum (regstack, clobber_reg[i]);
2615 /* Sigh - clobbers always have QImode. But replace_reg knows
2616 that these regs can't be MODE_INT and will abort. Just put
2617 the right reg there without calling replace_reg. */
2619 *clobber_loc[i] = FP_MODE_REG (regnum, DFmode);
2623 /* Now remove from REGSTACK any inputs that the asm implicitly popped. */
2625 for (i = first_input; i < first_input + n_inputs; i++)
2626 if (STACK_REG_P (operands[i]))
2628 /* An input reg is implicitly popped if it is tied to an
2629 output, or if there is a CLOBBER for it. */
2632 for (j = 0; j < n_clobbers; j++)
2633 if (operands_match_p (clobber_reg[j], operands[i]))
2636 if (j < n_clobbers || operand_matches[i] >= 0)
2638 /* operands[i] might not be at the top of stack. But that's OK,
2639 because all we need to do is pop the right number of regs
2640 off of the top of the reg-stack. record_asm_stack_regs
2641 guaranteed that all implicitly popped regs were grouped
2642 at the top of the reg-stack. */
2644 CLEAR_HARD_REG_BIT (regstack->reg_set,
2645 regstack->reg[regstack->top]);
2650 /* Now add to REGSTACK any outputs that the asm implicitly pushed.
2651 Note that there isn't any need to substitute register numbers.
2652 ??? Explain why this is true. */
2654 for (i = LAST_STACK_REG; i >= FIRST_STACK_REG; i--)
2656 /* See if there is an output for this hard reg. */
2659 for (j = 0; j < n_outputs; j++)
2660 if (STACK_REG_P (operands[j]) && REGNO (operands[j]) == i)
2662 regstack->reg[++regstack->top] = i;
2663 SET_HARD_REG_BIT (regstack->reg_set, i);
2668 /* Now emit a pop insn for any REG_UNUSED output, or any REG_DEAD
2669 input that the asm didn't implicitly pop. If the asm didn't
2670 implicitly pop an input reg, that reg will still be live.
2672 Note that we can't use find_regno_note here: the register numbers
2673 in the death notes have already been substituted. */
2675 for (i = 0; i < n_outputs; i++)
2676 if (STACK_REG_P (operands[i]))
2680 for (j = 0; j < n_notes; j++)
2681 if (REGNO (operands[i]) == REGNO (note_reg[j])
2682 && note_kind[j] == REG_UNUSED)
2684 insn = emit_pop_insn (insn, regstack, operands[i],
2690 for (i = first_input; i < first_input + n_inputs; i++)
2691 if (STACK_REG_P (operands[i]))
2695 for (j = 0; j < n_notes; j++)
2696 if (REGNO (operands[i]) == REGNO (note_reg[j])
2697 && note_kind[j] == REG_DEAD
2698 && TEST_HARD_REG_BIT (regstack->reg_set, REGNO (operands[i])))
2700 insn = emit_pop_insn (insn, regstack, operands[i],
2707 /* Substitute stack hard reg numbers for stack virtual registers in
2708 INSN. Non-stack register numbers are not changed. REGSTACK is the
2709 current stack content. Insns may be emitted as needed to arrange the
2710 stack for the 387 based on the contents of the insn. */
2713 subst_stack_regs (insn, regstack)
2717 register rtx *note_link, note;
2721 if (GET_CODE (insn) == CALL_INSN)
2723 int top = regstack->top;
2725 /* If there are any floating point parameters to be passed in
2726 registers for this call, make sure they are in the right
2731 straighten_stack (PREV_INSN (insn), regstack);
2733 /* Now mark the arguments as dead after the call. */
2735 while (regstack->top >= 0)
2737 CLEAR_HARD_REG_BIT (regstack->reg_set, FIRST_STACK_REG + regstack->top);
2743 /* Do the actual substitution if any stack regs are mentioned.
2744 Since we only record whether entire insn mentions stack regs, and
2745 subst_stack_regs_pat only works for patterns that contain stack regs,
2746 we must check each pattern in a parallel here. A call_value_pop could
2749 if (GET_MODE (insn) == QImode)
2751 n_operands = asm_noperands (PATTERN (insn));
2752 if (n_operands >= 0)
2754 /* This insn is an `asm' with operands. Decode the operands,
2755 decide how many are inputs, and do register substitution.
2756 Any REG_UNUSED notes will be handled by subst_asm_stack_regs. */
2758 rtx operands[MAX_RECOG_OPERANDS];
2759 rtx *operands_loc[MAX_RECOG_OPERANDS];
2760 rtx body = PATTERN (insn);
2761 int n_inputs, n_outputs;
2763 = (char **) alloca (n_operands * sizeof (char *));
2765 decode_asm_operands (body, operands, operands_loc,
2766 constraints, NULL_PTR);
2767 get_asm_operand_lengths (body, n_operands, &n_inputs, &n_outputs);
2768 subst_asm_stack_regs (insn, regstack, operands, operands_loc,
2769 constraints, n_inputs, n_outputs);
2773 if (GET_CODE (PATTERN (insn)) == PARALLEL)
2774 for (i = 0; i < XVECLEN (PATTERN (insn), 0); i++)
2776 if (stack_regs_mentioned_p (XVECEXP (PATTERN (insn), 0, i)))
2777 subst_stack_regs_pat (insn, regstack,
2778 XVECEXP (PATTERN (insn), 0, i));
2781 subst_stack_regs_pat (insn, regstack, PATTERN (insn));
2784 /* subst_stack_regs_pat may have deleted a no-op insn. If so, any
2785 REG_UNUSED will already have been dealt with, so just return. */
2787 if (GET_CODE (insn) == NOTE)
2790 /* If there is a REG_UNUSED note on a stack register on this insn,
2791 the indicated reg must be popped. The REG_UNUSED note is removed,
2792 since the form of the newly emitted pop insn references the reg,
2793 making it no longer `unset'. */
2795 note_link = ®_NOTES(insn);
2796 for (note = *note_link; note; note = XEXP (note, 1))
2797 if (REG_NOTE_KIND (note) == REG_UNUSED && STACK_REG_P (XEXP (note, 0)))
2799 *note_link = XEXP (note, 1);
2800 insn = emit_pop_insn (insn, regstack, XEXP (note, 0), emit_insn_after);
2803 note_link = &XEXP (note, 1);
2806 /* Change the organization of the stack so that it fits a new basic
2807 block. Some registers might have to be popped, but there can never be
2808 a register live in the new block that is not now live.
2810 Insert any needed insns before or after INSN. WHEN is emit_insn_before
2811 or emit_insn_after. OLD is the original stack layout, and NEW is
2812 the desired form. OLD is updated to reflect the code emitted, ie, it
2813 will be the same as NEW upon return.
2815 This function will not preserve block_end[]. But that information
2816 is no longer needed once this has executed. */
2819 change_stack (insn, old, new, when)
2827 /* We will be inserting new insns "backwards", by calling emit_insn_before.
2828 If we are to insert after INSN, find the next insn, and insert before
2831 if (when == emit_insn_after)
2832 insn = NEXT_INSN (insn);
2834 /* Pop any registers that are not needed in the new block. */
2836 for (reg = old->top; reg >= 0; reg--)
2837 if (! TEST_HARD_REG_BIT (new->reg_set, old->reg[reg]))
2838 emit_pop_insn (insn, old, FP_MODE_REG (old->reg[reg], DFmode),
2843 /* If the new block has never been processed, then it can inherit
2844 the old stack order. */
2846 new->top = old->top;
2847 bcopy (old->reg, new->reg, sizeof (new->reg));
2851 /* This block has been entered before, and we must match the
2852 previously selected stack order. */
2854 /* By now, the only difference should be the order of the stack,
2855 not their depth or liveliness. */
2857 GO_IF_HARD_REG_EQUAL (old->reg_set, new->reg_set, win);
2863 if (old->top != new->top)
2866 /* Loop here emitting swaps until the stack is correct. The
2867 worst case number of swaps emitted is N + 2, where N is the
2868 depth of the stack. In some cases, the reg at the top of
2869 stack may be correct, but swapped anyway in order to fix
2870 other regs. But since we never swap any other reg away from
2871 its correct slot, this algorithm will converge. */
2875 /* Swap the reg at top of stack into the position it is
2876 supposed to be in, until the correct top of stack appears. */
2878 while (old->reg[old->top] != new->reg[new->top])
2880 for (reg = new->top; reg >= 0; reg--)
2881 if (new->reg[reg] == old->reg[old->top])
2887 emit_swap_insn (insn, old,
2888 FP_MODE_REG (old->reg[reg], DFmode));
2891 /* See if any regs remain incorrect. If so, bring an
2892 incorrect reg to the top of stack, and let the while loop
2895 for (reg = new->top; reg >= 0; reg--)
2896 if (new->reg[reg] != old->reg[reg])
2898 emit_swap_insn (insn, old,
2899 FP_MODE_REG (old->reg[reg], DFmode));
2904 /* At this point there must be no differences. */
2906 for (reg = old->top; reg >= 0; reg--)
2907 if (old->reg[reg] != new->reg[reg])
2912 /* Check PAT, which points to RTL in INSN, for a LABEL_REF. If it is
2913 found, ensure that a jump from INSN to the code_label to which the
2914 label_ref points ends up with the same stack as that at the
2915 code_label. Do this by inserting insns just before the code_label to
2916 pop and rotate the stack until it is in the correct order. REGSTACK
2917 is the order of the register stack in INSN.
2919 Any code that is emitted here must not be later processed as part
2920 of any block, as it will already contain hard register numbers. */
2923 goto_block_pat (insn, regstack, pat)
2929 rtx new_jump, new_label, new_barrier;
2932 struct stack_def temp_stack;
2935 switch (GET_CODE (pat))
2938 straighten_stack (PREV_INSN (insn), regstack);
2943 char *fmt = GET_RTX_FORMAT (GET_CODE (pat));
2945 for (i = GET_RTX_LENGTH (GET_CODE (pat)) - 1; i >= 0; i--)
2948 goto_block_pat (insn, regstack, XEXP (pat, i));
2950 for (j = 0; j < XVECLEN (pat, i); j++)
2951 goto_block_pat (insn, regstack, XVECEXP (pat, i, j));
2958 label = XEXP (pat, 0);
2959 if (GET_CODE (label) != CODE_LABEL)
2962 /* First, see if in fact anything needs to be done to the stack at all. */
2963 if (INSN_UID (label) <= 0)
2966 label_stack = &block_stack_in[BLOCK_NUM (label)];
2968 if (label_stack->top == -2)
2970 /* If the target block hasn't had a stack order selected, then
2971 we need merely ensure that no pops are needed. */
2973 for (reg = regstack->top; reg >= 0; reg--)
2974 if (! TEST_HARD_REG_BIT (label_stack->reg_set, regstack->reg[reg]))
2979 /* change_stack will not emit any code in this case. */
2981 change_stack (label, regstack, label_stack, emit_insn_after);
2985 else if (label_stack->top == regstack->top)
2987 for (reg = label_stack->top; reg >= 0; reg--)
2988 if (label_stack->reg[reg] != regstack->reg[reg])
2995 /* At least one insn will need to be inserted before label. Insert
2996 a jump around the code we are about to emit. Emit a label for the new
2997 code, and point the original insn at this new label. We can't use
2998 redirect_jump here, because we're using fld[4] of the code labels as
2999 LABEL_REF chains, no NUSES counters. */
3001 new_jump = emit_jump_insn_before (gen_jump (label), label);
3002 record_label_references (new_jump, PATTERN (new_jump));
3003 JUMP_LABEL (new_jump) = label;
3005 new_barrier = emit_barrier_after (new_jump);
3007 new_label = gen_label_rtx ();
3008 emit_label_after (new_label, new_barrier);
3009 LABEL_REFS (new_label) = new_label;
3011 /* The old label_ref will no longer point to the code_label if now uses,
3012 so strip the label_ref from the code_label's chain of references. */
3014 for (ref = &LABEL_REFS (label); *ref != label; ref = &LABEL_NEXTREF (*ref))
3021 *ref = LABEL_NEXTREF (*ref);
3023 XEXP (pat, 0) = new_label;
3024 record_label_references (insn, PATTERN (insn));
3026 if (JUMP_LABEL (insn) == label)
3027 JUMP_LABEL (insn) = new_label;
3029 /* Now emit the needed code. */
3031 temp_stack = *regstack;
3033 change_stack (new_label, &temp_stack, label_stack, emit_insn_after);
3036 /* Traverse all basic blocks in a function, converting the register
3037 references in each insn from the "flat" register file that gcc uses, to
3038 the stack-like registers the 387 uses. */
3043 register int block, reg;
3044 register rtx insn, next;
3045 struct stack_def regstack;
3047 for (block = 0; block < blocks; block++)
3049 if (block_stack_in[block].top == -2)
3051 /* This block has not been previously encountered. Choose a
3052 default mapping for any stack regs live on entry */
3054 block_stack_in[block].top = -1;
3056 for (reg = LAST_STACK_REG; reg >= FIRST_STACK_REG; reg--)
3057 if (TEST_HARD_REG_BIT (block_stack_in[block].reg_set, reg))
3058 block_stack_in[block].reg[++block_stack_in[block].top] = reg;
3061 /* Process all insns in this block. Keep track of `next' here,
3062 so that we don't process any insns emitted while making
3063 substitutions in INSN. */
3065 next = block_begin[block];
3066 regstack = block_stack_in[block];
3070 next = NEXT_INSN (insn);
3072 /* Don't bother processing unless there is a stack reg
3073 mentioned or if it's a CALL_INSN (register passing of
3074 floating point values). */
3076 if (GET_MODE (insn) == QImode || GET_CODE (insn) == CALL_INSN)
3077 subst_stack_regs (insn, ®stack);
3079 } while (insn != block_end[block]);
3081 /* For all further actions, INSN needs to be the last insn in
3082 this basic block. If subst_stack_regs inserted additional
3083 instructions after INSN, it is no longer the last one at
3085 next = PREV_INSN (next);
3087 /* If subst_stack_regs inserted something after a JUMP_INSN, that
3088 is almost certainly a bug. */
3089 if (GET_CODE (insn) == JUMP_INSN && insn != next)
3093 /* Something failed if the stack life doesn't match. */
3095 GO_IF_HARD_REG_EQUAL (regstack.reg_set, block_out_reg_set[block], win);
3101 /* Adjust the stack of this block on exit to match the stack of
3102 the target block, or copy stack information into stack of
3103 jump target if the target block's stack order hasn't been set
3106 if (GET_CODE (insn) == JUMP_INSN)
3107 goto_block_pat (insn, ®stack, PATTERN (insn));
3109 /* Likewise handle the case where we fall into the next block. */
3111 if ((block < blocks - 1) && block_drops_in[block+1])
3112 change_stack (insn, ®stack, &block_stack_in[block+1],
3116 /* If the last basic block is the end of a loop, and that loop has
3117 regs live at its start, then the last basic block will have regs live
3118 at its end that need to be popped before the function returns. */
3121 int value_reg_low, value_reg_high;
3122 value_reg_low = value_reg_high = -1;
3125 if ((retvalue = stack_result (current_function_decl)))
3127 value_reg_low = REGNO (retvalue);
3128 value_reg_high = value_reg_low +
3129 HARD_REGNO_NREGS (value_reg_low, GET_MODE (retvalue)) - 1;
3133 for (reg = regstack.top; reg >= 0; reg--)
3134 if (regstack.reg[reg] < value_reg_low
3135 || regstack.reg[reg] > value_reg_high)
3136 insn = emit_pop_insn (insn, ®stack,
3137 FP_MODE_REG (regstack.reg[reg], DFmode),
3140 straighten_stack (insn, ®stack);
3143 /* Check expression PAT, which is in INSN, for label references. if
3144 one is found, print the block number of destination to FILE. */
3147 print_blocks (file, insn, pat)
3151 register RTX_CODE code = GET_CODE (pat);
3155 if (code == LABEL_REF)
3157 register rtx label = XEXP (pat, 0);
3159 if (GET_CODE (label) != CODE_LABEL)
3162 fprintf (file, " %d", BLOCK_NUM (label));
3167 fmt = GET_RTX_FORMAT (code);
3168 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3171 print_blocks (file, insn, XEXP (pat, i));
3175 for (j = 0; j < XVECLEN (pat, i); j++)
3176 print_blocks (file, insn, XVECEXP (pat, i, j));
3181 /* Write information about stack registers and stack blocks into FILE.
3182 This is part of making a debugging dump. */
3185 dump_stack_info (file)
3190 fprintf (file, "\n%d stack blocks.\n", blocks);
3191 for (block = 0; block < blocks; block++)
3193 register rtx head, jump, end;
3196 fprintf (file, "\nStack block %d: first insn %d, last %d.\n",
3197 block, INSN_UID (block_begin[block]),
3198 INSN_UID (block_end[block]));
3200 head = block_begin[block];
3202 fprintf (file, "Reached from blocks: ");
3203 if (GET_CODE (head) == CODE_LABEL)
3204 for (jump = LABEL_REFS (head);
3206 jump = LABEL_NEXTREF (jump))
3208 register int from_block = BLOCK_NUM (CONTAINING_INSN (jump));
3209 fprintf (file, " %d", from_block);
3211 if (block_drops_in[block])
3212 fprintf (file, " previous");
3214 fprintf (file, "\nlive stack registers on block entry: ");
3215 for (regno = FIRST_STACK_REG; regno <= LAST_STACK_REG; regno++)
3217 if (TEST_HARD_REG_BIT (block_stack_in[block].reg_set, regno))
3218 fprintf (file, "%d ", regno);
3221 fprintf (file, "\nlive stack registers on block exit: ");
3222 for (regno = FIRST_STACK_REG; regno <= LAST_STACK_REG; regno++)
3224 if (TEST_HARD_REG_BIT (block_out_reg_set[block], regno))
3225 fprintf (file, "%d ", regno);
3228 end = block_end[block];
3230 fprintf (file, "\nJumps to blocks: ");
3231 if (GET_CODE (end) == JUMP_INSN)
3232 print_blocks (file, end, PATTERN (end));
3234 if (block + 1 < blocks && block_drops_in[block+1])
3235 fprintf (file, " next");
3236 else if (block + 1 == blocks
3237 || (GET_CODE (end) == JUMP_INSN
3238 && GET_CODE (PATTERN (end)) == RETURN))
3239 fprintf (file, " return");
3241 fprintf (file, "\n");
3244 #endif /* STACK_REGS */