1 /* Register to Stack convert for GNU compiler.
2 Copyright (C) 1992, 93-99, 2000 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.
79 There are several rules on the usage of stack-like regs in
80 asm_operands insns. These rules apply only to the operands that are
83 1. Given a set of input regs that die in an asm_operands, it is
84 necessary to know which are implicitly popped by the asm, and
85 which must be explicitly popped by gcc.
87 An input reg that is implicitly popped by the asm must be
88 explicitly clobbered, unless it is constrained to match an
91 2. For any input reg that is implicitly popped by an asm, it is
92 necessary to know how to adjust the stack to compensate for the pop.
93 If any non-popped input is closer to the top of the reg-stack than
94 the implicitly popped reg, it would not be possible to know what the
95 stack looked like - it's not clear how the rest of the stack "slides
98 All implicitly popped input regs must be closer to the top of
99 the reg-stack than any input that is not implicitly popped.
101 3. It is possible that if an input dies in an insn, reload might
102 use the input reg for an output reload. Consider this example:
104 asm ("foo" : "=t" (a) : "f" (b));
106 This asm says that input B is not popped by the asm, and that
107 the asm pushes a result onto the reg-stack, ie, the stack is one
108 deeper after the asm than it was before. But, it is possible that
109 reload will think that it can use the same reg for both the input and
110 the output, if input B dies in this insn.
112 If any input operand uses the "f" constraint, all output reg
113 constraints must use the "&" earlyclobber.
115 The asm above would be written as
117 asm ("foo" : "=&t" (a) : "f" (b));
119 4. Some operands need to be in particular places on the stack. All
120 output operands fall in this category - there is no other way to
121 know which regs the outputs appear in unless the user indicates
122 this in the constraints.
124 Output operands must specifically indicate which reg an output
125 appears in after an asm. "=f" is not allowed: the operand
126 constraints must select a class with a single reg.
128 5. Output operands may not be "inserted" between existing stack regs.
129 Since no 387 opcode uses a read/write operand, all output operands
130 are dead before the asm_operands, and are pushed by the asm_operands.
131 It makes no sense to push anywhere but the top of the reg-stack.
133 Output operands must start at the top of the reg-stack: output
134 operands may not "skip" a reg.
136 6. Some asm statements may need extra stack space for internal
137 calculations. This can be guaranteed by clobbering stack registers
138 unrelated to the inputs and outputs.
140 Here are a couple of reasonable asms to want to write. This asm
141 takes one input, which is internally popped, and produces two outputs.
143 asm ("fsincos" : "=t" (cos), "=u" (sin) : "0" (inp));
145 This asm takes two inputs, which are popped by the fyl2xp1 opcode,
146 and replaces them with one output. The user must code the "st(1)"
147 clobber for reg-stack.c to know that fyl2xp1 pops both inputs.
149 asm ("fyl2xp1" : "=t" (result) : "0" (x), "u" (y) : "st(1)");
158 #include "function.h"
159 #include "insn-config.h"
161 #include "hard-reg-set.h"
163 #include "insn-flags.h"
167 #include "basic-block.h"
172 #define REG_STACK_SIZE (LAST_STACK_REG - FIRST_STACK_REG + 1)
174 /* This is the basic stack record. TOP is an index into REG[] such
175 that REG[TOP] is the top of stack. If TOP is -1 the stack is empty.
177 If TOP is -2, REG[] is not yet initialized. Stack initialization
178 consists of placing each live reg in array `reg' and setting `top'
181 REG_SET indicates which registers are live. */
183 typedef struct stack_def
185 int top; /* index to top stack element */
186 HARD_REG_SET reg_set; /* set of live registers */
187 char reg[REG_STACK_SIZE]; /* register - stack mapping */
190 /* This is used to carry information about basic blocks. It is
191 attached to the AUX field of the standard CFG block. */
193 typedef struct block_info_def
195 struct stack_def stack_in; /* Input stack configuration. */
196 HARD_REG_SET out_reg_set; /* Stack regs live on output. */
197 int done; /* True if block already converted. */
200 #define BLOCK_INFO(B) ((block_info) (B)->aux)
202 /* Passed to change_stack to indicate where to emit insns. */
209 /* We use this array to cache info about insns, because otherwise we
210 spend too much time in stack_regs_mentioned_p.
212 Indexed by insn UIDs. A value of zero is uninitialized, one indicates
213 the insn uses stack registers, two indicates the insn does not use
215 static varray_type stack_regs_mentioned_data;
217 /* The block we're currently working on. */
218 static basic_block current_block;
220 /* This is the register file for all register after conversion */
222 FP_mode_reg[LAST_STACK_REG+1-FIRST_STACK_REG][(int) MAX_MACHINE_MODE];
224 #define FP_MODE_REG(regno,mode) \
225 (FP_mode_reg[(regno)-FIRST_STACK_REG][(int)(mode)])
227 /* Used to initialize uninitialized registers. */
230 /* Forward declarations */
232 static int stack_regs_mentioned_p PROTO((rtx pat));
233 static void straighten_stack PROTO((rtx, stack));
234 static void pop_stack PROTO((stack, int));
235 static rtx *get_true_reg PROTO((rtx *));
237 static int check_asm_stack_operands PROTO((rtx));
238 static int get_asm_operand_n_inputs PROTO((rtx));
239 static rtx stack_result PROTO((tree));
240 static void replace_reg PROTO((rtx *, int));
241 static void remove_regno_note PROTO((rtx, enum reg_note, int));
242 static int get_hard_regnum PROTO((stack, rtx));
243 static void delete_insn_for_stacker PROTO((rtx));
244 static rtx emit_pop_insn PROTO((rtx, stack, rtx,
246 static void emit_swap_insn PROTO((rtx, stack, rtx));
247 static void move_for_stack_reg PROTO((rtx, stack, rtx));
248 static int swap_rtx_condition_1 PROTO((rtx));
249 static int swap_rtx_condition PROTO((rtx));
250 static void compare_for_stack_reg PROTO((rtx, stack, rtx));
251 static void subst_stack_regs_pat PROTO((rtx, stack, rtx));
252 static void subst_asm_stack_regs PROTO((rtx, stack));
253 static void subst_stack_regs PROTO((rtx, stack));
254 static void change_stack PROTO((rtx, stack, stack,
256 static int convert_regs_entry PROTO((void));
257 static void convert_regs_exit PROTO((void));
258 static int convert_regs_1 PROTO((FILE *, basic_block));
259 static int convert_regs_2 PROTO((FILE *, basic_block));
260 static int convert_regs PROTO((FILE *));
261 static void print_stack PROTO((FILE *, stack));
263 /* Return non-zero if any stack register is mentioned somewhere within PAT. */
266 stack_regs_mentioned_p (pat)
269 register const char *fmt;
272 if (STACK_REG_P (pat))
275 fmt = GET_RTX_FORMAT (GET_CODE (pat));
276 for (i = GET_RTX_LENGTH (GET_CODE (pat)) - 1; i >= 0; i--)
282 for (j = XVECLEN (pat, i) - 1; j >= 0; j--)
283 if (stack_regs_mentioned_p (XVECEXP (pat, i, j)))
286 else if (fmt[i] == 'e' && stack_regs_mentioned_p (XEXP (pat, i)))
293 /* Return nonzero if INSN mentions stacked registers, else return zero. */
296 stack_regs_mentioned (insn)
299 unsigned int uid, max;
302 if (GET_RTX_CLASS (GET_CODE (insn)) != 'i')
305 uid = INSN_UID (insn);
306 max = VARRAY_SIZE (stack_regs_mentioned_data);
309 /* Allocate some extra size to avoid too many reallocs, but
310 do not grow too quickly. */
311 max = uid + uid / 20;
312 VARRAY_GROW (stack_regs_mentioned_data, max);
315 test = VARRAY_CHAR (stack_regs_mentioned_data, uid);
318 /* This insn has yet to be examined. Do so now. */
319 test = stack_regs_mentioned_p (PATTERN (insn)) ? 1 : 2;
320 VARRAY_CHAR (stack_regs_mentioned_data, uid) = test;
326 static rtx ix86_flags_rtx;
329 next_flags_user (insn)
332 /* Search forward looking for the first use of this value.
333 Stop at block boundaries. */
334 /* ??? This really cries for BLOCK_END! */
338 insn = NEXT_INSN (insn);
342 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i'
343 && reg_mentioned_p (ix86_flags_rtx, PATTERN (insn)))
346 if (GET_CODE (insn) == JUMP_INSN
347 || GET_CODE (insn) == CODE_LABEL
348 || GET_CODE (insn) == CALL_INSN)
353 /* Reorganise the stack into ascending numbers,
357 straighten_stack (insn, regstack)
361 struct stack_def temp_stack;
364 /* If there is only a single register on the stack, then the stack is
365 already in increasing order and no reorganization is needed.
367 Similarly if the stack is empty. */
368 if (regstack->top <= 0)
371 COPY_HARD_REG_SET (temp_stack.reg_set, regstack->reg_set);
373 for (top = temp_stack.top = regstack->top; top >= 0; top--)
374 temp_stack.reg[top] = FIRST_STACK_REG + temp_stack.top - top;
376 change_stack (insn, regstack, &temp_stack, EMIT_AFTER);
379 /* Pop a register from the stack */
382 pop_stack (regstack, regno)
386 int top = regstack->top;
388 CLEAR_HARD_REG_BIT (regstack->reg_set, regno);
390 /* If regno was not at the top of stack then adjust stack */
391 if (regstack->reg [top] != regno)
394 for (i = regstack->top; i >= 0; i--)
395 if (regstack->reg [i] == regno)
398 for (j = i; j < top; j++)
399 regstack->reg [j] = regstack->reg [j + 1];
405 /* Convert register usage from "flat" register file usage to a "stack
406 register file. FIRST is the first insn in the function, FILE is the
409 Construct a CFG and run life analysis. Then convert each insn one
410 by one. Run a last jump_optimize pass, if optimizing, to eliminate
411 code duplication created when the converter inserts pop insns on
415 reg_to_stack (first, file)
423 /* See if there is something to do. Flow analysis is quite
424 expensive so we might save some compilation time. */
425 for (i = FIRST_STACK_REG; i <= LAST_STACK_REG; i++)
426 if (regs_ever_live[i])
428 if (i > LAST_STACK_REG)
431 /* Ok, floating point instructions exist. If not optimizing,
432 build the CFG and run life analysis. */
433 find_basic_blocks (first, max_reg_num (), file, 0);
434 count_or_remove_death_notes (NULL, 1);
435 life_analysis (first, max_reg_num (), file, 0);
437 /* Set up block info for each basic block. */
438 bi = (block_info) xcalloc ((n_basic_blocks + 1), sizeof (*bi));
439 for (i = n_basic_blocks - 1; i >= 0; --i)
440 BASIC_BLOCK (i)->aux = bi + i;
441 EXIT_BLOCK_PTR->aux = bi + n_basic_blocks;
443 /* Create the replacement registers up front. */
444 for (i = FIRST_STACK_REG; i <= LAST_STACK_REG; i++)
446 enum machine_mode mode;
447 for (mode = GET_CLASS_NARROWEST_MODE (MODE_FLOAT);
449 mode = GET_MODE_WIDER_MODE (mode))
450 FP_MODE_REG (i, mode) = gen_rtx_REG (mode, i);
451 for (mode = GET_CLASS_NARROWEST_MODE (MODE_COMPLEX_FLOAT);
453 mode = GET_MODE_WIDER_MODE (mode))
454 FP_MODE_REG (i, mode) = gen_rtx_REG (mode, i);
457 ix86_flags_rtx = gen_rtx_REG (CCmode, FLAGS_REG);
459 /* A QNaN for initializing uninitialized variables.
461 ??? We can't load from constant memory in PIC mode, because
462 we're insertting these instructions before the prologue and
463 the PIC register hasn't been set up. In that case, fall back
464 on zero, which we can get from `ldz'. */
467 nan = CONST0_RTX (SFmode);
470 nan = gen_lowpart (SFmode, GEN_INT (0x7fc00000));
471 nan = force_const_mem (SFmode, nan);
474 /* Allocate a cache for stack_regs_mentioned. */
475 max_uid = get_max_uid ();
476 VARRAY_CHAR_INIT (stack_regs_mentioned_data, max_uid + 1,
477 "stack_regs_mentioned cache");
479 if (convert_regs (file) && optimize)
481 jump_optimize (first, JUMP_CROSS_JUMP_DEATH_MATTERS,
482 !JUMP_NOOP_MOVES, !JUMP_AFTER_REGSCAN);
486 VARRAY_FREE (stack_regs_mentioned_data);
490 /* Check PAT, which is in INSN, for LABEL_REFs. Add INSN to the
491 label's chain of references, and note which insn contains each
495 record_label_references (insn, pat)
498 register enum rtx_code code = GET_CODE (pat);
500 register const char *fmt;
502 if (code == LABEL_REF)
504 register rtx label = XEXP (pat, 0);
507 if (GET_CODE (label) != CODE_LABEL)
510 /* If this is an undefined label, LABEL_REFS (label) contains
512 if (INSN_UID (label) == 0)
515 /* Don't make a duplicate in the code_label's chain. */
517 for (ref = LABEL_REFS (label);
519 ref = LABEL_NEXTREF (ref))
520 if (CONTAINING_INSN (ref) == insn)
523 CONTAINING_INSN (pat) = insn;
524 LABEL_NEXTREF (pat) = LABEL_REFS (label);
525 LABEL_REFS (label) = pat;
530 fmt = GET_RTX_FORMAT (code);
531 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
534 record_label_references (insn, XEXP (pat, i));
538 for (j = 0; j < XVECLEN (pat, i); j++)
539 record_label_references (insn, XVECEXP (pat, i, j));
544 /* Return a pointer to the REG expression within PAT. If PAT is not a
545 REG, possible enclosed by a conversion rtx, return the inner part of
546 PAT that stopped the search. */
553 switch (GET_CODE (*pat))
556 /* Eliminate FP subregister accesses in favour of the
557 actual FP register in use. */
560 if (FP_REG_P (subreg = SUBREG_REG (*pat)))
562 *pat = FP_MODE_REG (REGNO (subreg) + SUBREG_WORD (*pat),
571 pat = & XEXP (*pat, 0);
575 /* There are many rules that an asm statement for stack-like regs must
576 follow. Those rules are explained at the top of this file: the rule
577 numbers below refer to that explanation. */
580 check_asm_stack_operands (insn)
585 int malformed_asm = 0;
586 rtx body = PATTERN (insn);
588 char reg_used_as_output[FIRST_PSEUDO_REGISTER];
589 char implicitly_dies[FIRST_PSEUDO_REGISTER];
592 rtx *clobber_reg = 0;
593 int n_inputs, n_outputs;
595 /* Find out what the constraints require. If no constraint
596 alternative matches, this asm is malformed. */
598 constrain_operands (1);
599 alt = which_alternative;
601 preprocess_constraints ();
603 n_inputs = get_asm_operand_n_inputs (body);
604 n_outputs = recog_data.n_operands - n_inputs;
609 /* Avoid further trouble with this insn. */
610 PATTERN (insn) = gen_rtx_USE (VOIDmode, const0_rtx);
614 /* Strip SUBREGs here to make the following code simpler. */
615 for (i = 0; i < recog_data.n_operands; i++)
616 if (GET_CODE (recog_data.operand[i]) == SUBREG
617 && GET_CODE (SUBREG_REG (recog_data.operand[i])) == REG)
618 recog_data.operand[i] = SUBREG_REG (recog_data.operand[i]);
620 /* Set up CLOBBER_REG. */
624 if (GET_CODE (body) == PARALLEL)
626 clobber_reg = (rtx *) alloca (XVECLEN (body, 0) * sizeof (rtx));
628 for (i = 0; i < XVECLEN (body, 0); i++)
629 if (GET_CODE (XVECEXP (body, 0, i)) == CLOBBER)
631 rtx clobber = XVECEXP (body, 0, i);
632 rtx reg = XEXP (clobber, 0);
634 if (GET_CODE (reg) == SUBREG && GET_CODE (SUBREG_REG (reg)) == REG)
635 reg = SUBREG_REG (reg);
637 if (STACK_REG_P (reg))
639 clobber_reg[n_clobbers] = reg;
645 /* Enforce rule #4: Output operands must specifically indicate which
646 reg an output appears in after an asm. "=f" is not allowed: the
647 operand constraints must select a class with a single reg.
649 Also enforce rule #5: Output operands must start at the top of
650 the reg-stack: output operands may not "skip" a reg. */
652 memset (reg_used_as_output, 0, sizeof (reg_used_as_output));
653 for (i = 0; i < n_outputs; i++)
654 if (STACK_REG_P (recog_data.operand[i]))
656 if (reg_class_size[(int) recog_op_alt[i][alt].class] != 1)
658 error_for_asm (insn, "Output constraint %d must specify a single register", i);
662 reg_used_as_output[REGNO (recog_data.operand[i])] = 1;
666 /* Search for first non-popped reg. */
667 for (i = FIRST_STACK_REG; i < LAST_STACK_REG + 1; i++)
668 if (! reg_used_as_output[i])
671 /* If there are any other popped regs, that's an error. */
672 for (; i < LAST_STACK_REG + 1; i++)
673 if (reg_used_as_output[i])
676 if (i != LAST_STACK_REG + 1)
678 error_for_asm (insn, "Output regs must be grouped at top of stack");
682 /* Enforce rule #2: All implicitly popped input regs must be closer
683 to the top of the reg-stack than any input that is not implicitly
686 memset (implicitly_dies, 0, sizeof (implicitly_dies));
687 for (i = n_outputs; i < n_outputs + n_inputs; i++)
688 if (STACK_REG_P (recog_data.operand[i]))
690 /* An input reg is implicitly popped if it is tied to an
691 output, or if there is a CLOBBER for it. */
694 for (j = 0; j < n_clobbers; j++)
695 if (operands_match_p (clobber_reg[j], recog_data.operand[i]))
698 if (j < n_clobbers || recog_op_alt[i][alt].matches >= 0)
699 implicitly_dies[REGNO (recog_data.operand[i])] = 1;
702 /* Search for first non-popped reg. */
703 for (i = FIRST_STACK_REG; i < LAST_STACK_REG + 1; i++)
704 if (! implicitly_dies[i])
707 /* If there are any other popped regs, that's an error. */
708 for (; i < LAST_STACK_REG + 1; i++)
709 if (implicitly_dies[i])
712 if (i != LAST_STACK_REG + 1)
715 "Implicitly popped regs must be grouped at top of stack");
719 /* Enfore rule #3: If any input operand uses the "f" constraint, all
720 output constraints must use the "&" earlyclobber.
722 ??? Detect this more deterministically by having constrain_asm_operands
723 record any earlyclobber. */
725 for (i = n_outputs; i < n_outputs + n_inputs; i++)
726 if (recog_op_alt[i][alt].matches == -1)
730 for (j = 0; j < n_outputs; j++)
731 if (operands_match_p (recog_data.operand[j], recog_data.operand[i]))
734 "Output operand %d must use `&' constraint", j);
741 /* Avoid further trouble with this insn. */
742 PATTERN (insn) = gen_rtx_USE (VOIDmode, const0_rtx);
749 /* Calculate the number of inputs and outputs in BODY, an
750 asm_operands. N_OPERANDS is the total number of operands, and
751 N_INPUTS and N_OUTPUTS are pointers to ints into which the results are
755 get_asm_operand_n_inputs (body)
758 if (GET_CODE (body) == SET && GET_CODE (SET_SRC (body)) == ASM_OPERANDS)
759 return ASM_OPERANDS_INPUT_LENGTH (SET_SRC (body));
761 else if (GET_CODE (body) == ASM_OPERANDS)
762 return ASM_OPERANDS_INPUT_LENGTH (body);
764 else if (GET_CODE (body) == PARALLEL
765 && GET_CODE (XVECEXP (body, 0, 0)) == SET)
766 return ASM_OPERANDS_INPUT_LENGTH (SET_SRC (XVECEXP (body, 0, 0)));
768 else if (GET_CODE (body) == PARALLEL
769 && GET_CODE (XVECEXP (body, 0, 0)) == ASM_OPERANDS)
770 return ASM_OPERANDS_INPUT_LENGTH (XVECEXP (body, 0, 0));
775 /* If current function returns its result in an fp stack register,
776 return the REG. Otherwise, return 0. */
784 /* If the value is supposed to be returned in memory, then clearly
785 it is not returned in a stack register. */
786 if (aggregate_value_p (DECL_RESULT (decl)))
789 result = DECL_RTL (DECL_RESULT (decl));
790 /* ?!? What is this code supposed to do? Can this code actually
791 trigger if we kick out aggregates above? */
793 && ! (GET_CODE (result) == REG
794 && REGNO (result) < FIRST_PSEUDO_REGISTER))
796 #ifdef FUNCTION_OUTGOING_VALUE
798 = FUNCTION_OUTGOING_VALUE (TREE_TYPE (DECL_RESULT (decl)), decl);
800 result = FUNCTION_VALUE (TREE_TYPE (DECL_RESULT (decl)), decl);
804 return result != 0 && STACK_REG_P (result) ? result : 0;
809 * This section deals with stack register substitution, and forms the second
813 /* Replace REG, which is a pointer to a stack reg RTX, with an RTX for
814 the desired hard REGNO. */
817 replace_reg (reg, regno)
821 if (regno < FIRST_STACK_REG || regno > LAST_STACK_REG
822 || ! STACK_REG_P (*reg))
825 switch (GET_MODE_CLASS (GET_MODE (*reg)))
829 case MODE_COMPLEX_FLOAT:;
832 *reg = FP_MODE_REG (regno, GET_MODE (*reg));
835 /* Remove a note of type NOTE, which must be found, for register
836 number REGNO from INSN. Remove only one such note. */
839 remove_regno_note (insn, note, regno)
844 register rtx *note_link, this;
846 note_link = ®_NOTES(insn);
847 for (this = *note_link; this; this = XEXP (this, 1))
848 if (REG_NOTE_KIND (this) == note
849 && REG_P (XEXP (this, 0)) && REGNO (XEXP (this, 0)) == regno)
851 *note_link = XEXP (this, 1);
855 note_link = &XEXP (this, 1);
860 /* Find the hard register number of virtual register REG in REGSTACK.
861 The hard register number is relative to the top of the stack. -1 is
862 returned if the register is not found. */
865 get_hard_regnum (regstack, reg)
871 if (! STACK_REG_P (reg))
874 for (i = regstack->top; i >= 0; i--)
875 if (regstack->reg[i] == REGNO (reg))
878 return i >= 0 ? (FIRST_STACK_REG + regstack->top - i) : -1;
881 /* Delete INSN from the RTL. Mark the insn, but don't remove it from
882 the chain of insns. Doing so could confuse block_begin and block_end
883 if this were the only insn in the block. */
886 delete_insn_for_stacker (insn)
889 PUT_CODE (insn, NOTE);
890 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
891 NOTE_SOURCE_FILE (insn) = 0;
894 /* Emit an insn to pop virtual register REG before or after INSN.
895 REGSTACK is the stack state after INSN and is updated to reflect this
896 pop. WHEN is either emit_insn_before or emit_insn_after. A pop insn
897 is represented as a SET whose destination is the register to be popped
898 and source is the top of stack. A death note for the top of stack
899 cases the movdf pattern to pop. */
902 emit_pop_insn (insn, regstack, reg, where)
906 enum emit_where where;
908 rtx pop_insn, pop_rtx;
911 hard_regno = get_hard_regnum (regstack, reg);
913 if (hard_regno < FIRST_STACK_REG)
916 pop_rtx = gen_rtx_SET (VOIDmode, FP_MODE_REG (hard_regno, DFmode),
917 FP_MODE_REG (FIRST_STACK_REG, DFmode));
919 if (where == EMIT_AFTER)
920 pop_insn = emit_block_insn_after (pop_rtx, insn, current_block);
922 pop_insn = emit_block_insn_before (pop_rtx, insn, current_block);
925 = gen_rtx_EXPR_LIST (REG_DEAD, FP_MODE_REG (FIRST_STACK_REG, DFmode),
926 REG_NOTES (pop_insn));
928 regstack->reg[regstack->top - (hard_regno - FIRST_STACK_REG)]
929 = regstack->reg[regstack->top];
931 CLEAR_HARD_REG_BIT (regstack->reg_set, REGNO (reg));
936 /* Emit an insn before or after INSN to swap virtual register REG with
937 the top of stack. REGSTACK is the stack state before the swap, and
938 is updated to reflect the swap. A swap insn is represented as a
939 PARALLEL of two patterns: each pattern moves one reg to the other.
941 If REG is already at the top of the stack, no insn is emitted. */
944 emit_swap_insn (insn, regstack, reg)
951 int tmp, other_reg; /* swap regno temps */
952 rtx i1; /* the stack-reg insn prior to INSN */
953 rtx i1set = NULL_RTX; /* the SET rtx within I1 */
955 hard_regno = get_hard_regnum (regstack, reg);
957 if (hard_regno < FIRST_STACK_REG)
959 if (hard_regno == FIRST_STACK_REG)
962 other_reg = regstack->top - (hard_regno - FIRST_STACK_REG);
964 tmp = regstack->reg[other_reg];
965 regstack->reg[other_reg] = regstack->reg[regstack->top];
966 regstack->reg[regstack->top] = tmp;
968 /* Find the previous insn involving stack regs, but don't pass a
971 if (current_block && insn != current_block->head)
973 rtx tmp = PREV_INSN (insn);
974 while (tmp != current_block->head)
976 if (GET_CODE (tmp) == CODE_LABEL
977 || (GET_CODE (tmp) == NOTE
978 && NOTE_LINE_NUMBER (tmp) == NOTE_INSN_BASIC_BLOCK)
979 || (GET_CODE (tmp) == INSN
980 && stack_regs_mentioned (tmp)))
985 tmp = PREV_INSN (tmp);
990 && (i1set = single_set (i1)) != NULL_RTX)
992 rtx i1src = *get_true_reg (&SET_SRC (i1set));
993 rtx i1dest = *get_true_reg (&SET_DEST (i1set));
995 /* If the previous register stack push was from the reg we are to
996 swap with, omit the swap. */
998 if (GET_CODE (i1dest) == REG && REGNO (i1dest) == FIRST_STACK_REG
999 && GET_CODE (i1src) == REG && REGNO (i1src) == hard_regno - 1
1000 && find_regno_note (i1, REG_DEAD, FIRST_STACK_REG) == NULL_RTX)
1003 /* If the previous insn wrote to the reg we are to swap with,
1006 if (GET_CODE (i1dest) == REG && REGNO (i1dest) == hard_regno
1007 && GET_CODE (i1src) == REG && REGNO (i1src) == FIRST_STACK_REG
1008 && find_regno_note (i1, REG_DEAD, FIRST_STACK_REG) == NULL_RTX)
1012 swap_rtx = gen_swapxf (FP_MODE_REG (hard_regno, XFmode),
1013 FP_MODE_REG (FIRST_STACK_REG, XFmode));
1016 emit_block_insn_after (swap_rtx, i1, current_block);
1017 else if (current_block)
1019 i1 = emit_insn_before (swap_rtx, current_block->head);
1020 current_block->head = i1;
1023 emit_insn_before (swap_rtx, insn);
1026 /* Handle a move to or from a stack register in PAT, which is in INSN.
1027 REGSTACK is the current stack. */
1030 move_for_stack_reg (insn, regstack, pat)
1035 rtx *psrc = get_true_reg (&SET_SRC (pat));
1036 rtx *pdest = get_true_reg (&SET_DEST (pat));
1040 src = *psrc; dest = *pdest;
1042 if (STACK_REG_P (src) && STACK_REG_P (dest))
1044 /* Write from one stack reg to another. If SRC dies here, then
1045 just change the register mapping and delete the insn. */
1047 note = find_regno_note (insn, REG_DEAD, REGNO (src));
1052 /* If this is a no-op move, there must not be a REG_DEAD note. */
1053 if (REGNO (src) == REGNO (dest))
1056 for (i = regstack->top; i >= 0; i--)
1057 if (regstack->reg[i] == REGNO (src))
1060 /* The source must be live, and the dest must be dead. */
1061 if (i < 0 || get_hard_regnum (regstack, dest) >= FIRST_STACK_REG)
1064 /* It is possible that the dest is unused after this insn.
1065 If so, just pop the src. */
1067 if (find_regno_note (insn, REG_UNUSED, REGNO (dest)))
1069 emit_pop_insn (insn, regstack, src, EMIT_AFTER);
1071 delete_insn_for_stacker (insn);
1075 regstack->reg[i] = REGNO (dest);
1077 SET_HARD_REG_BIT (regstack->reg_set, REGNO (dest));
1078 CLEAR_HARD_REG_BIT (regstack->reg_set, REGNO (src));
1080 delete_insn_for_stacker (insn);
1085 /* The source reg does not die. */
1087 /* If this appears to be a no-op move, delete it, or else it
1088 will confuse the machine description output patterns. But if
1089 it is REG_UNUSED, we must pop the reg now, as per-insn processing
1090 for REG_UNUSED will not work for deleted insns. */
1092 if (REGNO (src) == REGNO (dest))
1094 if (find_regno_note (insn, REG_UNUSED, REGNO (dest)))
1095 emit_pop_insn (insn, regstack, dest, EMIT_AFTER);
1097 delete_insn_for_stacker (insn);
1101 /* The destination ought to be dead */
1102 if (get_hard_regnum (regstack, dest) >= FIRST_STACK_REG)
1105 replace_reg (psrc, get_hard_regnum (regstack, src));
1107 regstack->reg[++regstack->top] = REGNO (dest);
1108 SET_HARD_REG_BIT (regstack->reg_set, REGNO (dest));
1109 replace_reg (pdest, FIRST_STACK_REG);
1111 else if (STACK_REG_P (src))
1113 /* Save from a stack reg to MEM, or possibly integer reg. Since
1114 only top of stack may be saved, emit an exchange first if
1117 emit_swap_insn (insn, regstack, src);
1119 note = find_regno_note (insn, REG_DEAD, REGNO (src));
1122 replace_reg (&XEXP (note, 0), FIRST_STACK_REG);
1124 CLEAR_HARD_REG_BIT (regstack->reg_set, REGNO (src));
1126 else if (GET_MODE (src) == XFmode && regstack->top < REG_STACK_SIZE - 1)
1128 /* A 387 cannot write an XFmode value to a MEM without
1129 clobbering the source reg. The output code can handle
1130 this by reading back the value from the MEM.
1131 But it is more efficient to use a temp register if one is
1132 available. Push the source value here if the register
1133 stack is not full, and then write the value to memory via
1135 rtx push_rtx, push_insn;
1136 rtx top_stack_reg = FP_MODE_REG (FIRST_STACK_REG, XFmode);
1138 push_rtx = gen_movxf (top_stack_reg, top_stack_reg);
1139 push_insn = emit_insn_before (push_rtx, insn);
1140 REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_DEAD, top_stack_reg,
1144 replace_reg (psrc, FIRST_STACK_REG);
1146 else if (STACK_REG_P (dest))
1148 /* Load from MEM, or possibly integer REG or constant, into the
1149 stack regs. The actual target is always the top of the
1150 stack. The stack mapping is changed to reflect that DEST is
1151 now at top of stack. */
1153 /* The destination ought to be dead */
1154 if (get_hard_regnum (regstack, dest) >= FIRST_STACK_REG)
1157 if (regstack->top >= REG_STACK_SIZE)
1160 regstack->reg[++regstack->top] = REGNO (dest);
1161 SET_HARD_REG_BIT (regstack->reg_set, REGNO (dest));
1162 replace_reg (pdest, FIRST_STACK_REG);
1168 /* Swap the condition on a branch, if there is one. Return true if we
1169 found a condition to swap. False if the condition was not used as
1173 swap_rtx_condition_1 (pat)
1176 register const char *fmt;
1177 register int i, r = 0;
1179 if (GET_RTX_CLASS (GET_CODE (pat)) == '<')
1181 PUT_CODE (pat, swap_condition (GET_CODE (pat)));
1186 fmt = GET_RTX_FORMAT (GET_CODE (pat));
1187 for (i = GET_RTX_LENGTH (GET_CODE (pat)) - 1; i >= 0; i--)
1193 for (j = XVECLEN (pat, i) - 1; j >= 0; j--)
1194 r |= swap_rtx_condition_1 (XVECEXP (pat, i, j));
1196 else if (fmt[i] == 'e')
1197 r |= swap_rtx_condition_1 (XEXP (pat, i));
1205 swap_rtx_condition (insn)
1208 rtx pat = PATTERN (insn);
1210 /* We're looking for a single set to cc0 or an HImode temporary. */
1212 if (GET_CODE (pat) == SET
1213 && GET_CODE (SET_DEST (pat)) == REG
1214 && REGNO (SET_DEST (pat)) == FLAGS_REG)
1216 insn = next_flags_user (insn);
1217 if (insn == NULL_RTX)
1219 pat = PATTERN (insn);
1222 /* See if this is, or ends in, a fnstsw, aka unspec 9. If so, we're
1223 not doing anything with the cc value right now. We may be able to
1224 search for one though. */
1226 if (GET_CODE (pat) == SET
1227 && GET_CODE (SET_SRC (pat)) == UNSPEC
1228 && XINT (SET_SRC (pat), 1) == 9)
1230 rtx dest = SET_DEST (pat);
1232 /* Search forward looking for the first use of this value.
1233 Stop at block boundaries. */
1234 /* ??? This really cries for BLOCK_END! */
1237 insn = NEXT_INSN (insn);
1238 if (insn == NULL_RTX)
1240 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i'
1241 && reg_mentioned_p (dest, insn))
1243 if (GET_CODE (insn) == JUMP_INSN)
1245 if (GET_CODE (insn) == CODE_LABEL)
1249 /* So we've found the insn using this value. If it is anything
1250 other than sahf, aka unspec 10, or the value does not die
1251 (meaning we'd have to search further), then we must give up. */
1252 pat = PATTERN (insn);
1253 if (GET_CODE (pat) != SET
1254 || GET_CODE (SET_SRC (pat)) != UNSPEC
1255 || XINT (SET_SRC (pat), 1) != 10
1256 || ! dead_or_set_p (insn, dest))
1259 /* Now we are prepared to handle this as a normal cc0 setter. */
1260 insn = next_flags_user (insn);
1261 if (insn == NULL_RTX)
1263 pat = PATTERN (insn);
1266 return swap_rtx_condition_1 (pat);
1269 /* Handle a comparison. Special care needs to be taken to avoid
1270 causing comparisons that a 387 cannot do correctly, such as EQ.
1272 Also, a pop insn may need to be emitted. The 387 does have an
1273 `fcompp' insn that can pop two regs, but it is sometimes too expensive
1274 to do this - a `fcomp' followed by a `fstpl %st(0)' may be easier to
1278 compare_for_stack_reg (insn, regstack, pat_src)
1284 rtx src1_note, src2_note;
1287 src1 = get_true_reg (&XEXP (pat_src, 0));
1288 src2 = get_true_reg (&XEXP (pat_src, 1));
1289 flags_user = next_flags_user (insn);
1291 /* ??? If fxch turns out to be cheaper than fstp, give priority to
1292 registers that die in this insn - move those to stack top first. */
1293 if ((! STACK_REG_P (*src1)
1294 || (STACK_REG_P (*src2)
1295 && get_hard_regnum (regstack, *src2) == FIRST_STACK_REG))
1296 && swap_rtx_condition (insn))
1299 temp = XEXP (pat_src, 0);
1300 XEXP (pat_src, 0) = XEXP (pat_src, 1);
1301 XEXP (pat_src, 1) = temp;
1303 src1 = get_true_reg (&XEXP (pat_src, 0));
1304 src2 = get_true_reg (&XEXP (pat_src, 1));
1306 INSN_CODE (insn) = -1;
1309 /* We will fix any death note later. */
1311 src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
1313 if (STACK_REG_P (*src2))
1314 src2_note = find_regno_note (insn, REG_DEAD, REGNO (*src2));
1316 src2_note = NULL_RTX;
1318 emit_swap_insn (insn, regstack, *src1);
1320 replace_reg (src1, FIRST_STACK_REG);
1322 if (STACK_REG_P (*src2))
1323 replace_reg (src2, get_hard_regnum (regstack, *src2));
1327 pop_stack (regstack, REGNO (XEXP (src1_note, 0)));
1328 replace_reg (&XEXP (src1_note, 0), FIRST_STACK_REG);
1331 /* If the second operand dies, handle that. But if the operands are
1332 the same stack register, don't bother, because only one death is
1333 needed, and it was just handled. */
1336 && ! (STACK_REG_P (*src1) && STACK_REG_P (*src2)
1337 && REGNO (*src1) == REGNO (*src2)))
1339 /* As a special case, two regs may die in this insn if src2 is
1340 next to top of stack and the top of stack also dies. Since
1341 we have already popped src1, "next to top of stack" is really
1342 at top (FIRST_STACK_REG) now. */
1344 if (get_hard_regnum (regstack, XEXP (src2_note, 0)) == FIRST_STACK_REG
1347 pop_stack (regstack, REGNO (XEXP (src2_note, 0)));
1348 replace_reg (&XEXP (src2_note, 0), FIRST_STACK_REG + 1);
1352 /* The 386 can only represent death of the first operand in
1353 the case handled above. In all other cases, emit a separate
1354 pop and remove the death note from here. */
1356 /* link_cc0_insns (insn); */
1358 remove_regno_note (insn, REG_DEAD, REGNO (XEXP (src2_note, 0)));
1360 emit_pop_insn (insn, regstack, XEXP (src2_note, 0),
1366 /* Substitute new registers in PAT, which is part of INSN. REGSTACK
1367 is the current register layout. */
1370 subst_stack_regs_pat (insn, regstack, pat)
1377 switch (GET_CODE (pat))
1380 /* Deaths in USE insns can happen in non optimizing compilation.
1381 Handle them by popping the dying register. */
1382 src = get_true_reg (&XEXP (pat, 0));
1383 if (STACK_REG_P (*src)
1384 && find_regno_note (insn, REG_DEAD, REGNO (*src)))
1386 /* In stupid allocation the USE might be used to extend lifetime
1387 of variable to given scope. This may end up as USE of dead
1389 if (optimize || get_hard_regnum (regstack, *src) != -1)
1390 emit_pop_insn (insn, regstack, *src, EMIT_AFTER);
1393 else if (get_hard_regnum (regstack, *src) == -1)
1397 if (GET_CODE (PATTERN (insn)) != USE)
1399 PATTERN (insn) = gen_rtx_SET (GET_MODE (*src), *src,
1400 CONST0_RTX (GET_MODE (*src)));
1401 subst_stack_regs_pat (insn, regstack, PATTERN (insn));
1410 dest = get_true_reg (&XEXP (pat, 0));
1411 if (STACK_REG_P (*dest))
1413 note = find_reg_note (insn, REG_DEAD, *dest);
1415 if (pat != PATTERN (insn))
1417 /* The fix_truncdi_1 pattern wants to be able to allocate
1418 it's own scratch register. It does this by clobbering
1419 an fp reg so that it is assured of an empty reg-stack
1420 register. If the register is live, kill it now.
1421 Remove the DEAD/UNUSED note so we don't try to kill it
1425 emit_pop_insn (insn, regstack, *dest, EMIT_BEFORE);
1428 note = find_reg_note (insn, REG_UNUSED, *dest);
1432 remove_note (insn, note);
1433 replace_reg (dest, LAST_STACK_REG);
1437 /* A top-level clobber with no REG_DEAD, and no hard-regnum
1438 indicates an uninitialized value. Because reload removed
1439 all other clobbers, this must be due to a function
1440 returning without a value. Load up a NaN. */
1443 && get_hard_regnum (regstack, *dest) == -1)
1445 pat = gen_rtx_SET (VOIDmode,
1446 FP_MODE_REG (REGNO (*dest), SFmode),
1448 PATTERN (insn) = pat;
1449 move_for_stack_reg (insn, regstack, pat);
1458 rtx *src1 = (rtx *) NULL_PTR, *src2;
1459 rtx src1_note, src2_note;
1462 dest = get_true_reg (&SET_DEST (pat));
1463 src = get_true_reg (&SET_SRC (pat));
1464 pat_src = SET_SRC (pat);
1466 /* See if this is a `movM' pattern, and handle elsewhere if so. */
1467 if (STACK_REG_P (*src)
1468 || (STACK_REG_P (*dest)
1469 && (GET_CODE (*src) == REG || GET_CODE (*src) == MEM
1470 || GET_CODE (*src) == CONST_DOUBLE)))
1472 move_for_stack_reg (insn, regstack, pat);
1476 switch (GET_CODE (pat_src))
1479 compare_for_stack_reg (insn, regstack, pat_src);
1485 for (count = HARD_REGNO_NREGS (REGNO (*dest), GET_MODE (*dest));
1488 regstack->reg[++regstack->top] = REGNO (*dest) + count;
1489 SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest) + count);
1492 replace_reg (dest, FIRST_STACK_REG);
1496 /* This is a `tstM2' case. */
1497 if (*dest != cc0_rtx)
1503 case FLOAT_TRUNCATE:
1507 /* These insns only operate on the top of the stack. DEST might
1508 be cc0_rtx if we're processing a tstM pattern. Also, it's
1509 possible that the tstM case results in a REG_DEAD note on the
1513 src1 = get_true_reg (&XEXP (pat_src, 0));
1515 emit_swap_insn (insn, regstack, *src1);
1517 src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
1519 if (STACK_REG_P (*dest))
1520 replace_reg (dest, FIRST_STACK_REG);
1524 replace_reg (&XEXP (src1_note, 0), FIRST_STACK_REG);
1526 CLEAR_HARD_REG_BIT (regstack->reg_set, REGNO (*src1));
1529 replace_reg (src1, FIRST_STACK_REG);
1534 /* On i386, reversed forms of subM3 and divM3 exist for
1535 MODE_FLOAT, so the same code that works for addM3 and mulM3
1539 /* These insns can accept the top of stack as a destination
1540 from a stack reg or mem, or can use the top of stack as a
1541 source and some other stack register (possibly top of stack)
1542 as a destination. */
1544 src1 = get_true_reg (&XEXP (pat_src, 0));
1545 src2 = get_true_reg (&XEXP (pat_src, 1));
1547 /* We will fix any death note later. */
1549 if (STACK_REG_P (*src1))
1550 src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
1552 src1_note = NULL_RTX;
1553 if (STACK_REG_P (*src2))
1554 src2_note = find_regno_note (insn, REG_DEAD, REGNO (*src2));
1556 src2_note = NULL_RTX;
1558 /* If either operand is not a stack register, then the dest
1559 must be top of stack. */
1561 if (! STACK_REG_P (*src1) || ! STACK_REG_P (*src2))
1562 emit_swap_insn (insn, regstack, *dest);
1565 /* Both operands are REG. If neither operand is already
1566 at the top of stack, choose to make the one that is the dest
1567 the new top of stack. */
1569 int src1_hard_regnum, src2_hard_regnum;
1571 src1_hard_regnum = get_hard_regnum (regstack, *src1);
1572 src2_hard_regnum = get_hard_regnum (regstack, *src2);
1573 if (src1_hard_regnum == -1 || src2_hard_regnum == -1)
1576 if (src1_hard_regnum != FIRST_STACK_REG
1577 && src2_hard_regnum != FIRST_STACK_REG)
1578 emit_swap_insn (insn, regstack, *dest);
1581 if (STACK_REG_P (*src1))
1582 replace_reg (src1, get_hard_regnum (regstack, *src1));
1583 if (STACK_REG_P (*src2))
1584 replace_reg (src2, get_hard_regnum (regstack, *src2));
1588 rtx src1_reg = XEXP (src1_note, 0);
1590 /* If the register that dies is at the top of stack, then
1591 the destination is somewhere else - merely substitute it.
1592 But if the reg that dies is not at top of stack, then
1593 move the top of stack to the dead reg, as though we had
1594 done the insn and then a store-with-pop. */
1596 if (REGNO (src1_reg) == regstack->reg[regstack->top])
1598 SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
1599 replace_reg (dest, get_hard_regnum (regstack, *dest));
1603 int regno = get_hard_regnum (regstack, src1_reg);
1605 SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
1606 replace_reg (dest, regno);
1608 regstack->reg[regstack->top - (regno - FIRST_STACK_REG)]
1609 = regstack->reg[regstack->top];
1612 CLEAR_HARD_REG_BIT (regstack->reg_set,
1613 REGNO (XEXP (src1_note, 0)));
1614 replace_reg (&XEXP (src1_note, 0), FIRST_STACK_REG);
1619 rtx src2_reg = XEXP (src2_note, 0);
1620 if (REGNO (src2_reg) == regstack->reg[regstack->top])
1622 SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
1623 replace_reg (dest, get_hard_regnum (regstack, *dest));
1627 int regno = get_hard_regnum (regstack, src2_reg);
1629 SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
1630 replace_reg (dest, regno);
1632 regstack->reg[regstack->top - (regno - FIRST_STACK_REG)]
1633 = regstack->reg[regstack->top];
1636 CLEAR_HARD_REG_BIT (regstack->reg_set,
1637 REGNO (XEXP (src2_note, 0)));
1638 replace_reg (&XEXP (src2_note, 0), FIRST_STACK_REG);
1643 SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
1644 replace_reg (dest, get_hard_regnum (regstack, *dest));
1647 /* Keep operand 1 maching with destination. */
1648 if (GET_RTX_CLASS (GET_CODE (pat_src)) == 'c'
1649 && REG_P (*src1) && REG_P (*src2)
1650 && REGNO (*src1) != REGNO (*dest))
1659 switch (XINT (pat_src, 1))
1663 /* These insns only operate on the top of the stack. */
1665 src1 = get_true_reg (&XVECEXP (pat_src, 0, 0));
1667 emit_swap_insn (insn, regstack, *src1);
1669 src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
1671 if (STACK_REG_P (*dest))
1672 replace_reg (dest, FIRST_STACK_REG);
1676 replace_reg (&XEXP (src1_note, 0), FIRST_STACK_REG);
1678 CLEAR_HARD_REG_BIT (regstack->reg_set, REGNO (*src1));
1681 replace_reg (src1, FIRST_STACK_REG);
1685 /* (unspec [(unspec [(compare ..)] 9)] 10)
1686 Unspec 9 is fnstsw; unspec 10 is sahf. The combination
1687 matches the PPRO fcomi instruction. */
1689 pat_src = XVECEXP (pat_src, 0, 0);
1690 if (GET_CODE (pat_src) != UNSPEC
1691 || XINT (pat_src, 1) != 9)
1696 /* (unspec [(compare ..)] 9) */
1697 /* Combined fcomp+fnstsw generated for doing well with
1698 CSE. When optimizing this would have been broken
1701 pat_src = XVECEXP (pat_src, 0, 0);
1702 if (GET_CODE (pat_src) != COMPARE)
1705 compare_for_stack_reg (insn, regstack, pat_src);
1714 /* This insn requires the top of stack to be the destination. */
1716 /* If the comparison operator is an FP comparison operator,
1717 it is handled correctly by compare_for_stack_reg () who
1718 will move the destination to the top of stack. But if the
1719 comparison operator is not an FP comparison operator, we
1720 have to handle it here. */
1721 if (get_hard_regnum (regstack, *dest) >= FIRST_STACK_REG
1722 && REGNO (*dest) != regstack->reg[regstack->top])
1723 emit_swap_insn (insn, regstack, *dest);
1725 src1 = get_true_reg (&XEXP (pat_src, 1));
1726 src2 = get_true_reg (&XEXP (pat_src, 2));
1728 src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
1729 src2_note = find_regno_note (insn, REG_DEAD, REGNO (*src2));
1736 src_note[1] = src1_note;
1737 src_note[2] = src2_note;
1739 if (STACK_REG_P (*src1))
1740 replace_reg (src1, get_hard_regnum (regstack, *src1));
1741 if (STACK_REG_P (*src2))
1742 replace_reg (src2, get_hard_regnum (regstack, *src2));
1744 for (i = 1; i <= 2; i++)
1747 int regno = REGNO (XEXP (src_note[i], 0));
1749 /* If the register that dies is not at the top of
1750 stack, then move the top of stack to the dead reg */
1751 if (regno != regstack->reg[regstack->top])
1753 remove_regno_note (insn, REG_DEAD, regno);
1754 emit_pop_insn (insn, regstack, XEXP (src_note[i], 0),
1759 CLEAR_HARD_REG_BIT (regstack->reg_set, regno);
1760 replace_reg (&XEXP (src_note[i], 0), FIRST_STACK_REG);
1766 /* Make dest the top of stack. Add dest to regstack if
1768 if (get_hard_regnum (regstack, *dest) < FIRST_STACK_REG)
1769 regstack->reg[++regstack->top] = REGNO (*dest);
1770 SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
1771 replace_reg (dest, FIRST_STACK_REG);
1785 /* Substitute hard regnums for any stack regs in INSN, which has
1786 N_INPUTS inputs and N_OUTPUTS outputs. REGSTACK is the stack info
1787 before the insn, and is updated with changes made here.
1789 There are several requirements and assumptions about the use of
1790 stack-like regs in asm statements. These rules are enforced by
1791 record_asm_stack_regs; see comments there for details. Any
1792 asm_operands left in the RTL at this point may be assume to meet the
1793 requirements, since record_asm_stack_regs removes any problem asm. */
1796 subst_asm_stack_regs (insn, regstack)
1800 rtx body = PATTERN (insn);
1803 rtx *note_reg; /* Array of note contents */
1804 rtx **note_loc; /* Address of REG field of each note */
1805 enum reg_note *note_kind; /* The type of each note */
1807 rtx *clobber_reg = 0;
1808 rtx **clobber_loc = 0;
1810 struct stack_def temp_stack;
1815 int n_inputs, n_outputs;
1817 if (! check_asm_stack_operands (insn))
1820 /* Find out what the constraints required. If no constraint
1821 alternative matches, that is a compiler bug: we should have caught
1822 such an insn in check_asm_stack_operands. */
1823 extract_insn (insn);
1824 constrain_operands (1);
1825 alt = which_alternative;
1827 preprocess_constraints ();
1829 n_inputs = get_asm_operand_n_inputs (body);
1830 n_outputs = recog_data.n_operands - n_inputs;
1835 /* Strip SUBREGs here to make the following code simpler. */
1836 for (i = 0; i < recog_data.n_operands; i++)
1837 if (GET_CODE (recog_data.operand[i]) == SUBREG
1838 && GET_CODE (SUBREG_REG (recog_data.operand[i])) == REG)
1840 recog_data.operand_loc[i] = & SUBREG_REG (recog_data.operand[i]);
1841 recog_data.operand[i] = SUBREG_REG (recog_data.operand[i]);
1844 /* Set up NOTE_REG, NOTE_LOC and NOTE_KIND. */
1846 for (i = 0, note = REG_NOTES (insn); note; note = XEXP (note, 1))
1849 note_reg = (rtx *) alloca (i * sizeof (rtx));
1850 note_loc = (rtx **) alloca (i * sizeof (rtx *));
1851 note_kind = (enum reg_note *) alloca (i * sizeof (enum reg_note));
1854 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
1856 rtx reg = XEXP (note, 0);
1857 rtx *loc = & XEXP (note, 0);
1859 if (GET_CODE (reg) == SUBREG && GET_CODE (SUBREG_REG (reg)) == REG)
1861 loc = & SUBREG_REG (reg);
1862 reg = SUBREG_REG (reg);
1865 if (STACK_REG_P (reg)
1866 && (REG_NOTE_KIND (note) == REG_DEAD
1867 || REG_NOTE_KIND (note) == REG_UNUSED))
1869 note_reg[n_notes] = reg;
1870 note_loc[n_notes] = loc;
1871 note_kind[n_notes] = REG_NOTE_KIND (note);
1876 /* Set up CLOBBER_REG and CLOBBER_LOC. */
1880 if (GET_CODE (body) == PARALLEL)
1882 clobber_reg = (rtx *) alloca (XVECLEN (body, 0) * sizeof (rtx));
1883 clobber_loc = (rtx **) alloca (XVECLEN (body, 0) * sizeof (rtx *));
1885 for (i = 0; i < XVECLEN (body, 0); i++)
1886 if (GET_CODE (XVECEXP (body, 0, i)) == CLOBBER)
1888 rtx clobber = XVECEXP (body, 0, i);
1889 rtx reg = XEXP (clobber, 0);
1890 rtx *loc = & XEXP (clobber, 0);
1892 if (GET_CODE (reg) == SUBREG && GET_CODE (SUBREG_REG (reg)) == REG)
1894 loc = & SUBREG_REG (reg);
1895 reg = SUBREG_REG (reg);
1898 if (STACK_REG_P (reg))
1900 clobber_reg[n_clobbers] = reg;
1901 clobber_loc[n_clobbers] = loc;
1907 temp_stack = *regstack;
1909 /* Put the input regs into the desired place in TEMP_STACK. */
1911 for (i = n_outputs; i < n_outputs + n_inputs; i++)
1912 if (STACK_REG_P (recog_data.operand[i])
1913 && reg_class_subset_p (recog_op_alt[i][alt].class,
1915 && recog_op_alt[i][alt].class != FLOAT_REGS)
1917 /* If an operand needs to be in a particular reg in
1918 FLOAT_REGS, the constraint was either 't' or 'u'. Since
1919 these constraints are for single register classes, and
1920 reload guaranteed that operand[i] is already in that class,
1921 we can just use REGNO (recog_data.operand[i]) to know which
1922 actual reg this operand needs to be in. */
1924 int regno = get_hard_regnum (&temp_stack, recog_data.operand[i]);
1929 if (regno != REGNO (recog_data.operand[i]))
1931 /* recog_data.operand[i] is not in the right place. Find
1932 it and swap it with whatever is already in I's place.
1933 K is where recog_data.operand[i] is now. J is where it
1937 k = temp_stack.top - (regno - FIRST_STACK_REG);
1939 - (REGNO (recog_data.operand[i]) - FIRST_STACK_REG));
1941 temp = temp_stack.reg[k];
1942 temp_stack.reg[k] = temp_stack.reg[j];
1943 temp_stack.reg[j] = temp;
1947 /* Emit insns before INSN to make sure the reg-stack is in the right
1950 change_stack (insn, regstack, &temp_stack, EMIT_BEFORE);
1952 /* Make the needed input register substitutions. Do death notes and
1953 clobbers too, because these are for inputs, not outputs. */
1955 for (i = n_outputs; i < n_outputs + n_inputs; i++)
1956 if (STACK_REG_P (recog_data.operand[i]))
1958 int regnum = get_hard_regnum (regstack, recog_data.operand[i]);
1963 replace_reg (recog_data.operand_loc[i], regnum);
1966 for (i = 0; i < n_notes; i++)
1967 if (note_kind[i] == REG_DEAD)
1969 int regnum = get_hard_regnum (regstack, note_reg[i]);
1974 replace_reg (note_loc[i], regnum);
1977 for (i = 0; i < n_clobbers; i++)
1979 /* It's OK for a CLOBBER to reference a reg that is not live.
1980 Don't try to replace it in that case. */
1981 int regnum = get_hard_regnum (regstack, clobber_reg[i]);
1985 /* Sigh - clobbers always have QImode. But replace_reg knows
1986 that these regs can't be MODE_INT and will abort. Just put
1987 the right reg there without calling replace_reg. */
1989 *clobber_loc[i] = FP_MODE_REG (regnum, DFmode);
1993 /* Now remove from REGSTACK any inputs that the asm implicitly popped. */
1995 for (i = n_outputs; i < n_outputs + n_inputs; i++)
1996 if (STACK_REG_P (recog_data.operand[i]))
1998 /* An input reg is implicitly popped if it is tied to an
1999 output, or if there is a CLOBBER for it. */
2002 for (j = 0; j < n_clobbers; j++)
2003 if (operands_match_p (clobber_reg[j], recog_data.operand[i]))
2006 if (j < n_clobbers || recog_op_alt[i][alt].matches >= 0)
2008 /* recog_data.operand[i] might not be at the top of stack.
2009 But that's OK, because all we need to do is pop the
2010 right number of regs off of the top of the reg-stack.
2011 record_asm_stack_regs guaranteed that all implicitly
2012 popped regs were grouped at the top of the reg-stack. */
2014 CLEAR_HARD_REG_BIT (regstack->reg_set,
2015 regstack->reg[regstack->top]);
2020 /* Now add to REGSTACK any outputs that the asm implicitly pushed.
2021 Note that there isn't any need to substitute register numbers.
2022 ??? Explain why this is true. */
2024 for (i = LAST_STACK_REG; i >= FIRST_STACK_REG; i--)
2026 /* See if there is an output for this hard reg. */
2029 for (j = 0; j < n_outputs; j++)
2030 if (STACK_REG_P (recog_data.operand[j])
2031 && REGNO (recog_data.operand[j]) == i)
2033 regstack->reg[++regstack->top] = i;
2034 SET_HARD_REG_BIT (regstack->reg_set, i);
2039 /* Now emit a pop insn for any REG_UNUSED output, or any REG_DEAD
2040 input that the asm didn't implicitly pop. If the asm didn't
2041 implicitly pop an input reg, that reg will still be live.
2043 Note that we can't use find_regno_note here: the register numbers
2044 in the death notes have already been substituted. */
2046 for (i = 0; i < n_outputs; i++)
2047 if (STACK_REG_P (recog_data.operand[i]))
2051 for (j = 0; j < n_notes; j++)
2052 if (REGNO (recog_data.operand[i]) == REGNO (note_reg[j])
2053 && note_kind[j] == REG_UNUSED)
2055 insn = emit_pop_insn (insn, regstack, recog_data.operand[i],
2061 for (i = n_outputs; i < n_outputs + n_inputs; i++)
2062 if (STACK_REG_P (recog_data.operand[i]))
2066 for (j = 0; j < n_notes; j++)
2067 if (REGNO (recog_data.operand[i]) == REGNO (note_reg[j])
2068 && note_kind[j] == REG_DEAD
2069 && TEST_HARD_REG_BIT (regstack->reg_set,
2070 REGNO (recog_data.operand[i])))
2072 insn = emit_pop_insn (insn, regstack, recog_data.operand[i],
2079 /* Substitute stack hard reg numbers for stack virtual registers in
2080 INSN. Non-stack register numbers are not changed. REGSTACK is the
2081 current stack content. Insns may be emitted as needed to arrange the
2082 stack for the 387 based on the contents of the insn. */
2085 subst_stack_regs (insn, regstack)
2089 register rtx *note_link, note;
2092 if (GET_CODE (insn) == CALL_INSN)
2094 int top = regstack->top;
2096 /* If there are any floating point parameters to be passed in
2097 registers for this call, make sure they are in the right
2102 straighten_stack (PREV_INSN (insn), regstack);
2104 /* Now mark the arguments as dead after the call. */
2106 while (regstack->top >= 0)
2108 CLEAR_HARD_REG_BIT (regstack->reg_set, FIRST_STACK_REG + regstack->top);
2114 /* Do the actual substitution if any stack regs are mentioned.
2115 Since we only record whether entire insn mentions stack regs, and
2116 subst_stack_regs_pat only works for patterns that contain stack regs,
2117 we must check each pattern in a parallel here. A call_value_pop could
2120 if (stack_regs_mentioned (insn))
2122 int n_operands = asm_noperands (PATTERN (insn));
2123 if (n_operands >= 0)
2125 /* This insn is an `asm' with operands. Decode the operands,
2126 decide how many are inputs, and do register substitution.
2127 Any REG_UNUSED notes will be handled by subst_asm_stack_regs. */
2129 subst_asm_stack_regs (insn, regstack);
2133 if (GET_CODE (PATTERN (insn)) == PARALLEL)
2134 for (i = 0; i < XVECLEN (PATTERN (insn), 0); i++)
2136 if (stack_regs_mentioned_p (XVECEXP (PATTERN (insn), 0, i)))
2137 subst_stack_regs_pat (insn, regstack,
2138 XVECEXP (PATTERN (insn), 0, i));
2141 subst_stack_regs_pat (insn, regstack, PATTERN (insn));
2144 /* subst_stack_regs_pat may have deleted a no-op insn. If so, any
2145 REG_UNUSED will already have been dealt with, so just return. */
2147 if (GET_CODE (insn) == NOTE)
2150 /* If there is a REG_UNUSED note on a stack register on this insn,
2151 the indicated reg must be popped. The REG_UNUSED note is removed,
2152 since the form of the newly emitted pop insn references the reg,
2153 making it no longer `unset'. */
2155 note_link = ®_NOTES(insn);
2156 for (note = *note_link; note; note = XEXP (note, 1))
2157 if (REG_NOTE_KIND (note) == REG_UNUSED && STACK_REG_P (XEXP (note, 0)))
2159 *note_link = XEXP (note, 1);
2160 insn = emit_pop_insn (insn, regstack, XEXP (note, 0), EMIT_AFTER);
2163 note_link = &XEXP (note, 1);
2166 /* Change the organization of the stack so that it fits a new basic
2167 block. Some registers might have to be popped, but there can never be
2168 a register live in the new block that is not now live.
2170 Insert any needed insns before or after INSN, as indicated by
2171 WHERE. OLD is the original stack layout, and NEW is the desired
2172 form. OLD is updated to reflect the code emitted, ie, it will be
2173 the same as NEW upon return.
2175 This function will not preserve block_end[]. But that information
2176 is no longer needed once this has executed. */
2179 change_stack (insn, old, new, where)
2183 enum emit_where where;
2188 /* We will be inserting new insns "backwards". If we are to insert
2189 after INSN, find the next insn, and insert before it. */
2191 if (where == EMIT_AFTER)
2193 if (current_block && current_block->end == insn)
2195 insn = NEXT_INSN (insn);
2198 /* Pop any registers that are not needed in the new block. */
2200 for (reg = old->top; reg >= 0; reg--)
2201 if (! TEST_HARD_REG_BIT (new->reg_set, old->reg[reg]))
2202 emit_pop_insn (insn, old, FP_MODE_REG (old->reg[reg], DFmode),
2207 /* If the new block has never been processed, then it can inherit
2208 the old stack order. */
2210 new->top = old->top;
2211 memcpy (new->reg, old->reg, sizeof (new->reg));
2215 /* This block has been entered before, and we must match the
2216 previously selected stack order. */
2218 /* By now, the only difference should be the order of the stack,
2219 not their depth or liveliness. */
2221 GO_IF_HARD_REG_EQUAL (old->reg_set, new->reg_set, win);
2224 if (old->top != new->top)
2227 /* If the stack is not empty (new->top != -1), loop here emitting
2228 swaps until the stack is correct.
2230 The worst case number of swaps emitted is N + 2, where N is the
2231 depth of the stack. In some cases, the reg at the top of
2232 stack may be correct, but swapped anyway in order to fix
2233 other regs. But since we never swap any other reg away from
2234 its correct slot, this algorithm will converge. */
2239 /* Swap the reg at top of stack into the position it is
2240 supposed to be in, until the correct top of stack appears. */
2242 while (old->reg[old->top] != new->reg[new->top])
2244 for (reg = new->top; reg >= 0; reg--)
2245 if (new->reg[reg] == old->reg[old->top])
2251 emit_swap_insn (insn, old,
2252 FP_MODE_REG (old->reg[reg], DFmode));
2255 /* See if any regs remain incorrect. If so, bring an
2256 incorrect reg to the top of stack, and let the while loop
2259 for (reg = new->top; reg >= 0; reg--)
2260 if (new->reg[reg] != old->reg[reg])
2262 emit_swap_insn (insn, old,
2263 FP_MODE_REG (old->reg[reg], DFmode));
2268 /* At this point there must be no differences. */
2270 for (reg = old->top; reg >= 0; reg--)
2271 if (old->reg[reg] != new->reg[reg])
2276 current_block->end = PREV_INSN (insn);
2279 /* Print stack configuration. */
2282 print_stack (file, s)
2290 fprintf (file, "uninitialized\n");
2291 else if (s->top == -1)
2292 fprintf (file, "empty\n");
2297 for (i = 0; i <= s->top; ++i)
2298 fprintf (file, "%d ", s->reg[i]);
2299 fputs ("]\n", file);
2303 /* This function was doing life analysis. We now let the regular live
2304 code do it's job, so we only need to check some extra invariants
2305 that reg-stack expects. Primary among these being that all registers
2306 are initialized before use.
2308 The function returns true when code was emitted to CFG edges and
2309 commit_edge_insertions needs to be called. */
2312 convert_regs_entry ()
2314 int inserted = 0, i;
2317 for (i = n_basic_blocks - 1; i >= 0; --i)
2319 basic_block block = BASIC_BLOCK (i);
2320 block_info bi = BLOCK_INFO (block);
2323 /* Set current register status at last instruction `uninitialized'. */
2324 bi->stack_in.top = -2;
2326 /* Copy live_at_end and live_at_start into temporaries. */
2327 for (reg = FIRST_STACK_REG; reg <= LAST_STACK_REG; reg++)
2329 if (REGNO_REG_SET_P (block->global_live_at_end, reg))
2330 SET_HARD_REG_BIT (bi->out_reg_set, reg);
2331 if (REGNO_REG_SET_P (block->global_live_at_start, reg))
2332 SET_HARD_REG_BIT (bi->stack_in.reg_set, reg);
2336 /* Load something into each stack register live at function entry.
2337 Such live registers can be caused by uninitialized variables or
2338 functions not returning values on all paths. In order to keep
2339 the push/pop code happy, and to not scrog the register stack, we
2340 must put something in these registers. Use a QNaN.
2342 Note that we are insertting converted code here. This code is
2343 never seen by the convert_regs pass. */
2345 for (e = ENTRY_BLOCK_PTR->succ; e ; e = e->succ_next)
2347 basic_block block = e->dest;
2348 block_info bi = BLOCK_INFO (block);
2351 for (reg = LAST_STACK_REG; reg >= FIRST_STACK_REG; --reg)
2352 if (TEST_HARD_REG_BIT (bi->stack_in.reg_set, reg))
2356 bi->stack_in.reg[++top] = reg;
2358 init = gen_rtx_SET (VOIDmode,
2359 FP_MODE_REG (FIRST_STACK_REG, SFmode),
2361 insert_insn_on_edge (init, e);
2365 bi->stack_in.top = top;
2371 /* Construct the desired stack for function exit. This will either
2372 be `empty', or the function return value at top-of-stack. */
2375 convert_regs_exit ()
2377 int value_reg_low, value_reg_high;
2381 retvalue = stack_result (current_function_decl);
2382 value_reg_low = value_reg_high = -1;
2385 value_reg_low = REGNO (retvalue);
2386 value_reg_high = value_reg_low
2387 + HARD_REGNO_NREGS (value_reg_low, GET_MODE (retvalue)) - 1;
2390 output_stack = &BLOCK_INFO (EXIT_BLOCK_PTR)->stack_in;
2391 if (value_reg_low == -1)
2392 output_stack->top = -1;
2397 output_stack->top = value_reg_high - value_reg_low;
2398 for (reg = value_reg_low; reg <= value_reg_high; ++reg)
2400 output_stack->reg[reg - value_reg_low] = reg;
2401 SET_HARD_REG_BIT (output_stack->reg_set, reg);
2406 /* Convert stack register references in one block. */
2409 convert_regs_1 (file, block)
2413 struct stack_def regstack, tmpstack;
2414 block_info bi = BLOCK_INFO (block);
2419 current_block = block;
2423 fprintf (file, "\nBasic block %d\nInput stack: ", block->index);
2424 print_stack (file, &bi->stack_in);
2427 /* Process all insns in this block. Keep track of NEXT so that we
2428 don't process insns emitted while substituting in INSN. */
2430 regstack = bi->stack_in;
2434 next = NEXT_INSN (insn);
2436 /* Ensure we have not missed a block boundary. */
2439 if (insn == block->end)
2442 /* Don't bother processing unless there is a stack reg
2443 mentioned or if it's a CALL_INSN. */
2444 if (stack_regs_mentioned (insn)
2445 || GET_CODE (insn) == CALL_INSN)
2449 fprintf (file, " insn %d input stack: ",
2451 print_stack (file, ®stack);
2453 subst_stack_regs (insn, ®stack);
2460 fprintf (file, "Expected live registers [");
2461 for (reg = FIRST_STACK_REG; reg <= LAST_STACK_REG; ++reg)
2462 if (TEST_HARD_REG_BIT (bi->out_reg_set, reg))
2463 fprintf (file, " %d", reg);
2464 fprintf (file, " ]\nOutput stack: ");
2465 print_stack (file, ®stack);
2469 if (GET_CODE (insn) == JUMP_INSN)
2470 insn = PREV_INSN (insn);
2472 /* If the function is declared to return a value, but it returns one
2473 in only some cases, some registers might come live here. Emit
2474 necessary moves for them. */
2476 for (reg = FIRST_STACK_REG; reg <= LAST_STACK_REG; ++reg)
2478 if (TEST_HARD_REG_BIT (bi->out_reg_set, reg)
2479 && ! TEST_HARD_REG_BIT (regstack.reg_set, reg))
2485 fprintf (file, "Emitting insn initializing reg %d\n",
2489 set = gen_rtx_SET (VOIDmode, FP_MODE_REG (reg, SFmode),
2491 insn = emit_block_insn_after (set, insn, block);
2492 subst_stack_regs (insn, ®stack);
2496 /* Something failed if the stack lives don't match. */
2497 GO_IF_HARD_REG_EQUAL (regstack.reg_set, bi->out_reg_set, win);
2501 /* Adjust the stack of this block on exit to match the stack of the
2502 target block, or copy stack info into the stack of the successor
2503 of the successor hasn't been processed yet. */
2505 for (e = block->succ; e ; e = e->succ_next)
2507 basic_block target = e->dest;
2508 stack target_stack = &BLOCK_INFO (target)->stack_in;
2511 fprintf (file, "Edge to block %d: ", target->index);
2513 if (target_stack->top == -2)
2515 /* The target block hasn't had a stack order selected.
2516 We need merely ensure that no pops are needed. */
2517 for (reg = regstack.top; reg >= 0; --reg)
2518 if (! TEST_HARD_REG_BIT (target_stack->reg_set,
2525 fprintf (file, "new block; copying stack position\n");
2527 /* change_stack kills values in regstack. */
2528 tmpstack = regstack;
2530 change_stack (block->end, &tmpstack,
2531 target_stack, EMIT_AFTER);
2536 fprintf (file, "new block; pops needed\n");
2540 if (target_stack->top == regstack.top)
2542 for (reg = target_stack->top; reg >= 0; --reg)
2543 if (target_stack->reg[reg] != regstack.reg[reg])
2549 fprintf (file, "no changes needed\n");
2556 fprintf (file, "correcting stack to ");
2557 print_stack (file, target_stack);
2561 /* Care for EH edges specially. The normal return path may return
2562 a value in st(0), but the EH path will not, and there's no need
2563 to add popping code to the edge. */
2564 if (e->flags & EDGE_EH)
2566 /* Assert that the lifetimes are as we expect -- one value
2567 live at st(0) on the end of the source block, and no
2568 values live at the beginning of the destination block. */
2571 CLEAR_HARD_REG_SET (tmp);
2572 GO_IF_HARD_REG_EQUAL (target_stack->reg_set, tmp, eh1);
2576 SET_HARD_REG_BIT (tmp, FIRST_STACK_REG);
2577 GO_IF_HARD_REG_EQUAL (regstack.reg_set, tmp, eh2);
2581 target_stack->top = -1;
2584 /* It is better to output directly to the end of the block
2585 instead of to the edge, because emit_swap can do minimal
2586 insn scheduling. We can do this when there is only one
2587 edge out, and it is not abnormal. */
2588 else if (block->succ->succ_next == NULL
2589 && ! (e->flags & EDGE_ABNORMAL))
2591 /* change_stack kills values in regstack. */
2592 tmpstack = regstack;
2594 change_stack (block->end, &tmpstack, target_stack,
2595 (GET_CODE (block->end) == JUMP_INSN
2596 ? EMIT_BEFORE : EMIT_AFTER));
2602 /* We don't support abnormal edges. Global takes care to
2603 avoid any live register across them, so we should never
2604 have to insert instructions on such edges. */
2605 if (e->flags & EDGE_ABNORMAL)
2608 current_block = NULL;
2611 /* ??? change_stack needs some point to emit insns after.
2612 Also needed to keep gen_sequence from returning a
2613 pattern as opposed to a sequence, which would lose
2615 after = emit_note (NULL, NOTE_INSN_DELETED);
2617 tmpstack = regstack;
2618 change_stack (after, &tmpstack, target_stack, EMIT_BEFORE);
2620 seq = gen_sequence ();
2623 insert_insn_on_edge (seq, e);
2625 current_block = block;
2632 /* Convert registers in all blocks reachable from BLOCK. */
2635 convert_regs_2 (file, block)
2639 basic_block *stack, *sp;
2642 stack = (basic_block *) xmalloc (sizeof (*stack) * n_basic_blocks);
2646 BLOCK_INFO (block)->done = 1;
2654 inserted |= convert_regs_1 (file, block);
2656 for (e = block->succ; e ; e = e->succ_next)
2657 if (! BLOCK_INFO (e->dest)->done)
2660 BLOCK_INFO (e->dest)->done = 1;
2663 while (sp != stack);
2668 /* Traverse all basic blocks in a function, converting the register
2669 references in each insn from the "flat" register file that gcc uses,
2670 to the stack-like registers the 387 uses. */
2679 /* Initialize uninitialized registers on function entry. */
2680 inserted = convert_regs_entry ();
2682 /* Construct the desired stack for function exit. */
2683 convert_regs_exit ();
2684 BLOCK_INFO (EXIT_BLOCK_PTR)->done = 1;
2686 /* ??? Future: process inner loops first, and give them arbitrary
2687 initial stacks which emit_swap_insn can modify. This ought to
2688 prevent double fxch that aften appears at the head of a loop. */
2690 /* Process all blocks reachable from all entry points. */
2691 for (e = ENTRY_BLOCK_PTR->succ; e ; e = e->succ_next)
2692 inserted |= convert_regs_2 (file, e->dest);
2694 /* ??? Process all unreachable blocks. Though there's no excuse
2695 for keeping these even when not optimizing. */
2696 for (i = 0; i < n_basic_blocks; ++i)
2698 basic_block b = BASIC_BLOCK (i);
2699 block_info bi = BLOCK_INFO (b);
2705 /* Create an arbitrary input stack. */
2706 bi->stack_in.top = -1;
2707 for (reg = LAST_STACK_REG; reg >= FIRST_STACK_REG; --reg)
2708 if (TEST_HARD_REG_BIT (bi->stack_in.reg_set, reg))
2709 bi->stack_in.reg[++bi->stack_in.top] = reg;
2711 inserted |= convert_regs_2 (file, b);
2716 commit_edge_insertions ();
2723 #endif /* STACK_REGS */