1 /* Register to Stack convert for GNU compiler.
2 Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
3 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 GCC is distributed in the hope that it will be useful, but WITHOUT
13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
15 License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
22 /* This pass converts stack-like registers from the "flat register
23 file" model that gcc uses, to a stack convention that the 387 uses.
25 * The form of the input:
27 On input, the function consists of insn that have had their
28 registers fully allocated to a set of "virtual" registers. Note that
29 the word "virtual" is used differently here than elsewhere in gcc: for
30 each virtual stack reg, there is a hard reg, but the mapping between
31 them is not known until this pass is run. On output, hard register
32 numbers have been substituted, and various pop and exchange insns have
33 been emitted. The hard register numbers and the virtual register
34 numbers completely overlap - before this pass, all stack register
35 numbers are virtual, and afterward they are all hard.
37 The virtual registers can be manipulated normally by gcc, and their
38 semantics are the same as for normal registers. After the hard
39 register numbers are substituted, the semantics of an insn containing
40 stack-like regs are not the same as for an insn with normal regs: for
41 instance, it is not safe to delete an insn that appears to be a no-op
42 move. In general, no insn containing hard regs should be changed
43 after this pass is done.
45 * The form of the output:
47 After this pass, hard register numbers represent the distance from
48 the current top of stack to the desired register. A reference to
49 FIRST_STACK_REG references the top of stack, FIRST_STACK_REG + 1,
50 represents the register just below that, and so forth. Also, REG_DEAD
51 notes indicate whether or not a stack register should be popped.
53 A "swap" insn looks like a parallel of two patterns, where each
54 pattern is a SET: one sets A to B, the other B to A.
56 A "push" or "load" insn is a SET whose SET_DEST is FIRST_STACK_REG
57 and whose SET_DEST is REG or MEM. Any other SET_DEST, such as PLUS,
58 will replace the existing stack top, not push a new value.
60 A store insn is a SET whose SET_DEST is FIRST_STACK_REG, and whose
61 SET_SRC is REG or MEM.
63 The case where the SET_SRC and SET_DEST are both FIRST_STACK_REG
64 appears ambiguous. As a special case, the presence of a REG_DEAD note
65 for FIRST_STACK_REG differentiates between a load insn and a pop.
67 If a REG_DEAD is present, the insn represents a "pop" that discards
68 the top of the register stack. If there is no REG_DEAD note, then the
69 insn represents a "dup" or a push of the current top of stack onto the
74 Existing REG_DEAD and REG_UNUSED notes for stack registers are
75 deleted and recreated from scratch. REG_DEAD is never created for a
76 SET_DEST, only REG_UNUSED.
80 There are several rules on the usage of stack-like regs in
81 asm_operands insns. These rules apply only to the operands that are
84 1. Given a set of input regs that die in an asm_operands, it is
85 necessary to know which are implicitly popped by the asm, and
86 which must be explicitly popped by gcc.
88 An input reg that is implicitly popped by the asm must be
89 explicitly clobbered, unless it is constrained to match an
92 2. For any input reg that is implicitly popped by an asm, it is
93 necessary to know how to adjust the stack to compensate for the pop.
94 If any non-popped input is closer to the top of the reg-stack than
95 the implicitly popped reg, it would not be possible to know what the
96 stack looked like - it's not clear how the rest of the stack "slides
99 All implicitly popped input regs must be closer to the top of
100 the reg-stack than any input that is not implicitly popped.
102 3. It is possible that if an input dies in an insn, reload might
103 use the input reg for an output reload. Consider this example:
105 asm ("foo" : "=t" (a) : "f" (b));
107 This asm says that input B is not popped by the asm, and that
108 the asm pushes a result onto the reg-stack, ie, the stack is one
109 deeper after the asm than it was before. But, it is possible that
110 reload will think that it can use the same reg for both the input and
111 the output, if input B dies in this insn.
113 If any input operand uses the "f" constraint, all output reg
114 constraints must use the "&" earlyclobber.
116 The asm above would be written as
118 asm ("foo" : "=&t" (a) : "f" (b));
120 4. Some operands need to be in particular places on the stack. All
121 output operands fall in this category - there is no other way to
122 know which regs the outputs appear in unless the user indicates
123 this in the constraints.
125 Output operands must specifically indicate which reg an output
126 appears in after an asm. "=f" is not allowed: the operand
127 constraints must select a class with a single reg.
129 5. Output operands may not be "inserted" between existing stack regs.
130 Since no 387 opcode uses a read/write operand, all output operands
131 are dead before the asm_operands, and are pushed by the asm_operands.
132 It makes no sense to push anywhere but the top of the reg-stack.
134 Output operands must start at the top of the reg-stack: output
135 operands may not "skip" a reg.
137 6. Some asm statements may need extra stack space for internal
138 calculations. This can be guaranteed by clobbering stack registers
139 unrelated to the inputs and outputs.
141 Here are a couple of reasonable asms to want to write. This asm
142 takes one input, which is internally popped, and produces two outputs.
144 asm ("fsincos" : "=t" (cos), "=u" (sin) : "0" (inp));
146 This asm takes two inputs, which are popped by the fyl2xp1 opcode,
147 and replaces them with one output. The user must code the "st(1)"
148 clobber for reg-stack.c to know that fyl2xp1 pops both inputs.
150 asm ("fyl2xp1" : "=t" (result) : "0" (x), "u" (y) : "st(1)");
156 #include "coretypes.h"
161 #include "function.h"
162 #include "insn-config.h"
164 #include "hard-reg-set.h"
169 #include "basic-block.h"
174 /* We use this array to cache info about insns, because otherwise we
175 spend too much time in stack_regs_mentioned_p.
177 Indexed by insn UIDs. A value of zero is uninitialized, one indicates
178 the insn uses stack registers, two indicates the insn does not use
180 static GTY(()) varray_type stack_regs_mentioned_data;
184 #define REG_STACK_SIZE (LAST_STACK_REG - FIRST_STACK_REG + 1)
186 /* This is the basic stack record. TOP is an index into REG[] such
187 that REG[TOP] is the top of stack. If TOP is -1 the stack is empty.
189 If TOP is -2, REG[] is not yet initialized. Stack initialization
190 consists of placing each live reg in array `reg' and setting `top'
193 REG_SET indicates which registers are live. */
195 typedef struct stack_def
197 int top; /* index to top stack element */
198 HARD_REG_SET reg_set; /* set of live registers */
199 unsigned char reg[REG_STACK_SIZE];/* register - stack mapping */
202 /* This is used to carry information about basic blocks. It is
203 attached to the AUX field of the standard CFG block. */
205 typedef struct block_info_def
207 struct stack_def stack_in; /* Input stack configuration. */
208 struct stack_def stack_out; /* Output stack configuration. */
209 HARD_REG_SET out_reg_set; /* Stack regs live on output. */
210 int done; /* True if block already converted. */
211 int predecessors; /* Number of predecessors that needs
215 #define BLOCK_INFO(B) ((block_info) (B)->aux)
217 /* Passed to change_stack to indicate where to emit insns. */
224 /* The block we're currently working on. */
225 static basic_block current_block;
227 /* This is the register file for all register after conversion. */
229 FP_mode_reg[LAST_STACK_REG+1-FIRST_STACK_REG][(int) MAX_MACHINE_MODE];
231 #define FP_MODE_REG(regno,mode) \
232 (FP_mode_reg[(regno)-FIRST_STACK_REG][(int) (mode)])
234 /* Used to initialize uninitialized registers. */
237 /* Forward declarations */
239 static int stack_regs_mentioned_p (rtx pat);
240 static void straighten_stack (rtx, stack);
241 static void pop_stack (stack, int);
242 static rtx *get_true_reg (rtx *);
244 static int check_asm_stack_operands (rtx);
245 static int get_asm_operand_n_inputs (rtx);
246 static rtx stack_result (tree);
247 static void replace_reg (rtx *, int);
248 static void remove_regno_note (rtx, enum reg_note, unsigned int);
249 static int get_hard_regnum (stack, rtx);
250 static rtx emit_pop_insn (rtx, stack, rtx, enum emit_where);
251 static void emit_swap_insn (rtx, stack, rtx);
252 static bool move_for_stack_reg (rtx, stack, rtx);
253 static int swap_rtx_condition_1 (rtx);
254 static int swap_rtx_condition (rtx);
255 static void compare_for_stack_reg (rtx, stack, rtx);
256 static bool subst_stack_regs_pat (rtx, stack, rtx);
257 static void subst_asm_stack_regs (rtx, stack);
258 static bool subst_stack_regs (rtx, stack);
259 static void change_stack (rtx, stack, stack, enum emit_where);
260 static int convert_regs_entry (void);
261 static void convert_regs_exit (void);
262 static int convert_regs_1 (FILE *, basic_block);
263 static int convert_regs_2 (FILE *, basic_block);
264 static int convert_regs (FILE *);
265 static void print_stack (FILE *, stack);
266 static rtx next_flags_user (rtx);
267 static void record_label_references (rtx, rtx);
268 static bool compensate_edge (edge, FILE *);
270 /* Return nonzero if any stack register is mentioned somewhere within PAT. */
273 stack_regs_mentioned_p (rtx pat)
278 if (STACK_REG_P (pat))
281 fmt = GET_RTX_FORMAT (GET_CODE (pat));
282 for (i = GET_RTX_LENGTH (GET_CODE (pat)) - 1; i >= 0; i--)
288 for (j = XVECLEN (pat, i) - 1; j >= 0; j--)
289 if (stack_regs_mentioned_p (XVECEXP (pat, i, j)))
292 else if (fmt[i] == 'e' && stack_regs_mentioned_p (XEXP (pat, i)))
299 /* Return nonzero if INSN mentions stacked registers, else return zero. */
302 stack_regs_mentioned (rtx insn)
304 unsigned int uid, max;
307 if (! INSN_P (insn) || !stack_regs_mentioned_data)
310 uid = INSN_UID (insn);
311 max = VARRAY_SIZE (stack_regs_mentioned_data);
314 /* Allocate some extra size to avoid too many reallocs, but
315 do not grow too quickly. */
316 max = uid + uid / 20;
317 VARRAY_GROW (stack_regs_mentioned_data, max);
320 test = VARRAY_CHAR (stack_regs_mentioned_data, uid);
323 /* This insn has yet to be examined. Do so now. */
324 test = stack_regs_mentioned_p (PATTERN (insn)) ? 1 : 2;
325 VARRAY_CHAR (stack_regs_mentioned_data, uid) = test;
331 static rtx ix86_flags_rtx;
334 next_flags_user (rtx insn)
336 /* Search forward looking for the first use of this value.
337 Stop at block boundaries. */
339 while (insn != BB_END (current_block))
341 insn = NEXT_INSN (insn);
343 if (INSN_P (insn) && reg_mentioned_p (ix86_flags_rtx, PATTERN (insn)))
346 if (GET_CODE (insn) == CALL_INSN)
352 /* Reorganize the stack into ascending numbers,
356 straighten_stack (rtx insn, stack regstack)
358 struct stack_def temp_stack;
361 /* If there is only a single register on the stack, then the stack is
362 already in increasing order and no reorganization is needed.
364 Similarly if the stack is empty. */
365 if (regstack->top <= 0)
368 COPY_HARD_REG_SET (temp_stack.reg_set, regstack->reg_set);
370 for (top = temp_stack.top = regstack->top; top >= 0; top--)
371 temp_stack.reg[top] = FIRST_STACK_REG + temp_stack.top - top;
373 change_stack (insn, regstack, &temp_stack, EMIT_AFTER);
376 /* Pop a register from the stack. */
379 pop_stack (stack regstack, int regno)
381 int top = regstack->top;
383 CLEAR_HARD_REG_BIT (regstack->reg_set, regno);
385 /* If regno was not at the top of stack then adjust stack. */
386 if (regstack->reg [top] != regno)
389 for (i = regstack->top; i >= 0; i--)
390 if (regstack->reg [i] == regno)
393 for (j = i; j < top; j++)
394 regstack->reg [j] = regstack->reg [j + 1];
400 /* Convert register usage from "flat" register file usage to a "stack
401 register file. FIRST is the first insn in the function, FILE is the
404 Construct a CFG and run life analysis. Then convert each insn one
405 by one. Run a last cleanup_cfg pass, if optimizing, to eliminate
406 code duplication created when the converter inserts pop insns on
410 reg_to_stack (rtx first, FILE *file)
416 /* Clean up previous run. */
417 stack_regs_mentioned_data = 0;
419 /* See if there is something to do. Flow analysis is quite
420 expensive so we might save some compilation time. */
421 for (i = FIRST_STACK_REG; i <= LAST_STACK_REG; i++)
422 if (regs_ever_live[i])
424 if (i > LAST_STACK_REG)
427 /* Ok, floating point instructions exist. If not optimizing,
428 build the CFG and run life analysis.
429 Also need to rebuild life when superblock scheduling is done
430 as it don't update liveness yet. */
432 || (flag_sched2_use_superblocks
433 && flag_schedule_insns_after_reload))
435 count_or_remove_death_notes (NULL, 1);
436 life_analysis (first, file, PROP_DEATH_NOTES);
438 mark_dfs_back_edges ();
440 /* Set up block info for each basic block. */
441 alloc_aux_for_blocks (sizeof (struct block_info_def));
442 FOR_EACH_BB_REVERSE (bb)
445 for (e = bb->pred; e; e = e->pred_next)
446 if (!(e->flags & EDGE_DFS_BACK)
447 && e->src != ENTRY_BLOCK_PTR)
448 BLOCK_INFO (bb)->predecessors++;
451 /* Create the replacement registers up front. */
452 for (i = FIRST_STACK_REG; i <= LAST_STACK_REG; i++)
454 enum machine_mode mode;
455 for (mode = GET_CLASS_NARROWEST_MODE (MODE_FLOAT);
457 mode = GET_MODE_WIDER_MODE (mode))
458 FP_MODE_REG (i, mode) = gen_rtx_REG (mode, i);
459 for (mode = GET_CLASS_NARROWEST_MODE (MODE_COMPLEX_FLOAT);
461 mode = GET_MODE_WIDER_MODE (mode))
462 FP_MODE_REG (i, mode) = gen_rtx_REG (mode, i);
465 ix86_flags_rtx = gen_rtx_REG (CCmode, FLAGS_REG);
467 /* A QNaN for initializing uninitialized variables.
469 ??? We can't load from constant memory in PIC mode, because
470 we're inserting these instructions before the prologue and
471 the PIC register hasn't been set up. In that case, fall back
472 on zero, which we can get from `ldz'. */
475 nan = CONST0_RTX (SFmode);
478 nan = gen_lowpart (SFmode, GEN_INT (0x7fc00000));
479 nan = force_const_mem (SFmode, nan);
482 /* Allocate a cache for stack_regs_mentioned. */
483 max_uid = get_max_uid ();
484 VARRAY_CHAR_INIT (stack_regs_mentioned_data, max_uid + 1,
485 "stack_regs_mentioned cache");
489 free_aux_for_blocks ();
493 /* Check PAT, which is in INSN, for LABEL_REFs. Add INSN to the
494 label's chain of references, and note which insn contains each
498 record_label_references (rtx insn, rtx pat)
500 enum rtx_code code = GET_CODE (pat);
504 if (code == LABEL_REF)
506 rtx label = XEXP (pat, 0);
509 if (GET_CODE (label) != CODE_LABEL)
512 /* If this is an undefined label, LABEL_REFS (label) contains
514 if (INSN_UID (label) == 0)
517 /* Don't make a duplicate in the code_label's chain. */
519 for (ref = LABEL_REFS (label);
521 ref = LABEL_NEXTREF (ref))
522 if (CONTAINING_INSN (ref) == insn)
525 CONTAINING_INSN (pat) = insn;
526 LABEL_NEXTREF (pat) = LABEL_REFS (label);
527 LABEL_REFS (label) = pat;
532 fmt = GET_RTX_FORMAT (code);
533 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
536 record_label_references (insn, XEXP (pat, i));
540 for (j = 0; j < XVECLEN (pat, i); j++)
541 record_label_references (insn, XVECEXP (pat, i, j));
546 /* Return a pointer to the REG expression within PAT. If PAT is not a
547 REG, possible enclosed by a conversion rtx, return the inner part of
548 PAT that stopped the search. */
551 get_true_reg (rtx *pat)
554 switch (GET_CODE (*pat))
557 /* Eliminate FP subregister accesses in favor of the
558 actual FP register in use. */
561 if (FP_REG_P (subreg = SUBREG_REG (*pat)))
563 int regno_off = subreg_regno_offset (REGNO (subreg),
567 *pat = FP_MODE_REG (REGNO (subreg) + regno_off,
576 pat = & XEXP (*pat, 0);
580 if (!flag_unsafe_math_optimizations)
582 pat = & XEXP (*pat, 0);
587 /* Set if we find any malformed asms in a block. */
588 static bool any_malformed_asm;
590 /* There are many rules that an asm statement for stack-like regs must
591 follow. Those rules are explained at the top of this file: the rule
592 numbers below refer to that explanation. */
595 check_asm_stack_operands (rtx insn)
599 int malformed_asm = 0;
600 rtx body = PATTERN (insn);
602 char reg_used_as_output[FIRST_PSEUDO_REGISTER];
603 char implicitly_dies[FIRST_PSEUDO_REGISTER];
606 rtx *clobber_reg = 0;
607 int n_inputs, n_outputs;
609 /* Find out what the constraints require. If no constraint
610 alternative matches, this asm is malformed. */
612 constrain_operands (1);
613 alt = which_alternative;
615 preprocess_constraints ();
617 n_inputs = get_asm_operand_n_inputs (body);
618 n_outputs = recog_data.n_operands - n_inputs;
623 /* Avoid further trouble with this insn. */
624 PATTERN (insn) = gen_rtx_USE (VOIDmode, const0_rtx);
628 /* Strip SUBREGs here to make the following code simpler. */
629 for (i = 0; i < recog_data.n_operands; i++)
630 if (GET_CODE (recog_data.operand[i]) == SUBREG
631 && GET_CODE (SUBREG_REG (recog_data.operand[i])) == REG)
632 recog_data.operand[i] = SUBREG_REG (recog_data.operand[i]);
634 /* Set up CLOBBER_REG. */
638 if (GET_CODE (body) == PARALLEL)
640 clobber_reg = alloca (XVECLEN (body, 0) * sizeof (rtx));
642 for (i = 0; i < XVECLEN (body, 0); i++)
643 if (GET_CODE (XVECEXP (body, 0, i)) == CLOBBER)
645 rtx clobber = XVECEXP (body, 0, i);
646 rtx reg = XEXP (clobber, 0);
648 if (GET_CODE (reg) == SUBREG && GET_CODE (SUBREG_REG (reg)) == REG)
649 reg = SUBREG_REG (reg);
651 if (STACK_REG_P (reg))
653 clobber_reg[n_clobbers] = reg;
659 /* Enforce rule #4: Output operands must specifically indicate which
660 reg an output appears in after an asm. "=f" is not allowed: the
661 operand constraints must select a class with a single reg.
663 Also enforce rule #5: Output operands must start at the top of
664 the reg-stack: output operands may not "skip" a reg. */
666 memset (reg_used_as_output, 0, sizeof (reg_used_as_output));
667 for (i = 0; i < n_outputs; i++)
668 if (STACK_REG_P (recog_data.operand[i]))
670 if (reg_class_size[(int) recog_op_alt[i][alt].class] != 1)
672 error_for_asm (insn, "output constraint %d must specify a single register", i);
679 for (j = 0; j < n_clobbers; j++)
680 if (REGNO (recog_data.operand[i]) == REGNO (clobber_reg[j]))
682 error_for_asm (insn, "output constraint %d cannot be specified together with \"%s\" clobber",
683 i, reg_names [REGNO (clobber_reg[j])]);
688 reg_used_as_output[REGNO (recog_data.operand[i])] = 1;
693 /* Search for first non-popped reg. */
694 for (i = FIRST_STACK_REG; i < LAST_STACK_REG + 1; i++)
695 if (! reg_used_as_output[i])
698 /* If there are any other popped regs, that's an error. */
699 for (; i < LAST_STACK_REG + 1; i++)
700 if (reg_used_as_output[i])
703 if (i != LAST_STACK_REG + 1)
705 error_for_asm (insn, "output regs must be grouped at top of stack");
709 /* Enforce rule #2: All implicitly popped input regs must be closer
710 to the top of the reg-stack than any input that is not implicitly
713 memset (implicitly_dies, 0, sizeof (implicitly_dies));
714 for (i = n_outputs; i < n_outputs + n_inputs; i++)
715 if (STACK_REG_P (recog_data.operand[i]))
717 /* An input reg is implicitly popped if it is tied to an
718 output, or if there is a CLOBBER for it. */
721 for (j = 0; j < n_clobbers; j++)
722 if (operands_match_p (clobber_reg[j], recog_data.operand[i]))
725 if (j < n_clobbers || recog_op_alt[i][alt].matches >= 0)
726 implicitly_dies[REGNO (recog_data.operand[i])] = 1;
729 /* Search for first non-popped reg. */
730 for (i = FIRST_STACK_REG; i < LAST_STACK_REG + 1; i++)
731 if (! implicitly_dies[i])
734 /* If there are any other popped regs, that's an error. */
735 for (; i < LAST_STACK_REG + 1; i++)
736 if (implicitly_dies[i])
739 if (i != LAST_STACK_REG + 1)
742 "implicitly popped regs must be grouped at top of stack");
746 /* Enforce rule #3: If any input operand uses the "f" constraint, all
747 output constraints must use the "&" earlyclobber.
749 ??? Detect this more deterministically by having constrain_asm_operands
750 record any earlyclobber. */
752 for (i = n_outputs; i < n_outputs + n_inputs; i++)
753 if (recog_op_alt[i][alt].matches == -1)
757 for (j = 0; j < n_outputs; j++)
758 if (operands_match_p (recog_data.operand[j], recog_data.operand[i]))
761 "output operand %d must use `&' constraint", j);
768 /* Avoid further trouble with this insn. */
769 PATTERN (insn) = gen_rtx_USE (VOIDmode, const0_rtx);
770 any_malformed_asm = true;
777 /* Calculate the number of inputs and outputs in BODY, an
778 asm_operands. N_OPERANDS is the total number of operands, and
779 N_INPUTS and N_OUTPUTS are pointers to ints into which the results are
783 get_asm_operand_n_inputs (rtx body)
785 if (GET_CODE (body) == SET && GET_CODE (SET_SRC (body)) == ASM_OPERANDS)
786 return ASM_OPERANDS_INPUT_LENGTH (SET_SRC (body));
788 else if (GET_CODE (body) == ASM_OPERANDS)
789 return ASM_OPERANDS_INPUT_LENGTH (body);
791 else if (GET_CODE (body) == PARALLEL
792 && GET_CODE (XVECEXP (body, 0, 0)) == SET)
793 return ASM_OPERANDS_INPUT_LENGTH (SET_SRC (XVECEXP (body, 0, 0)));
795 else if (GET_CODE (body) == PARALLEL
796 && GET_CODE (XVECEXP (body, 0, 0)) == ASM_OPERANDS)
797 return ASM_OPERANDS_INPUT_LENGTH (XVECEXP (body, 0, 0));
802 /* If current function returns its result in an fp stack register,
803 return the REG. Otherwise, return 0. */
806 stack_result (tree decl)
810 /* If the value is supposed to be returned in memory, then clearly
811 it is not returned in a stack register. */
812 if (aggregate_value_p (DECL_RESULT (decl), decl))
815 result = DECL_RTL_IF_SET (DECL_RESULT (decl));
818 #ifdef FUNCTION_OUTGOING_VALUE
820 = FUNCTION_OUTGOING_VALUE (TREE_TYPE (DECL_RESULT (decl)), decl);
822 result = FUNCTION_VALUE (TREE_TYPE (DECL_RESULT (decl)), decl);
826 return result != 0 && STACK_REG_P (result) ? result : 0;
831 * This section deals with stack register substitution, and forms the second
835 /* Replace REG, which is a pointer to a stack reg RTX, with an RTX for
836 the desired hard REGNO. */
839 replace_reg (rtx *reg, int regno)
841 if (regno < FIRST_STACK_REG || regno > LAST_STACK_REG
842 || ! STACK_REG_P (*reg))
845 switch (GET_MODE_CLASS (GET_MODE (*reg)))
849 case MODE_COMPLEX_FLOAT:;
852 *reg = FP_MODE_REG (regno, GET_MODE (*reg));
855 /* Remove a note of type NOTE, which must be found, for register
856 number REGNO from INSN. Remove only one such note. */
859 remove_regno_note (rtx insn, enum reg_note note, unsigned int regno)
861 rtx *note_link, this;
863 note_link = ®_NOTES (insn);
864 for (this = *note_link; this; this = XEXP (this, 1))
865 if (REG_NOTE_KIND (this) == note
866 && REG_P (XEXP (this, 0)) && REGNO (XEXP (this, 0)) == regno)
868 *note_link = XEXP (this, 1);
872 note_link = &XEXP (this, 1);
877 /* Find the hard register number of virtual register REG in REGSTACK.
878 The hard register number is relative to the top of the stack. -1 is
879 returned if the register is not found. */
882 get_hard_regnum (stack regstack, rtx reg)
886 if (! STACK_REG_P (reg))
889 for (i = regstack->top; i >= 0; i--)
890 if (regstack->reg[i] == REGNO (reg))
893 return i >= 0 ? (FIRST_STACK_REG + regstack->top - i) : -1;
896 /* Emit an insn to pop virtual register REG before or after INSN.
897 REGSTACK is the stack state after INSN and is updated to reflect this
898 pop. WHEN is either emit_insn_before or emit_insn_after. A pop insn
899 is represented as a SET whose destination is the register to be popped
900 and source is the top of stack. A death note for the top of stack
901 cases the movdf pattern to pop. */
904 emit_pop_insn (rtx insn, stack regstack, rtx reg, enum emit_where where)
906 rtx pop_insn, pop_rtx;
909 /* For complex types take care to pop both halves. These may survive in
910 CLOBBER and USE expressions. */
911 if (COMPLEX_MODE_P (GET_MODE (reg)))
913 rtx reg1 = FP_MODE_REG (REGNO (reg), DFmode);
914 rtx reg2 = FP_MODE_REG (REGNO (reg) + 1, DFmode);
917 if (get_hard_regnum (regstack, reg1) >= 0)
918 pop_insn = emit_pop_insn (insn, regstack, reg1, where);
919 if (get_hard_regnum (regstack, reg2) >= 0)
920 pop_insn = emit_pop_insn (insn, regstack, reg2, where);
926 hard_regno = get_hard_regnum (regstack, reg);
928 if (hard_regno < FIRST_STACK_REG)
931 pop_rtx = gen_rtx_SET (VOIDmode, FP_MODE_REG (hard_regno, DFmode),
932 FP_MODE_REG (FIRST_STACK_REG, DFmode));
934 if (where == EMIT_AFTER)
935 pop_insn = emit_insn_after (pop_rtx, insn);
937 pop_insn = emit_insn_before (pop_rtx, insn);
940 = gen_rtx_EXPR_LIST (REG_DEAD, FP_MODE_REG (FIRST_STACK_REG, DFmode),
941 REG_NOTES (pop_insn));
943 regstack->reg[regstack->top - (hard_regno - FIRST_STACK_REG)]
944 = regstack->reg[regstack->top];
946 CLEAR_HARD_REG_BIT (regstack->reg_set, REGNO (reg));
951 /* Emit an insn before or after INSN to swap virtual register REG with
952 the top of stack. REGSTACK is the stack state before the swap, and
953 is updated to reflect the swap. A swap insn is represented as a
954 PARALLEL of two patterns: each pattern moves one reg to the other.
956 If REG is already at the top of the stack, no insn is emitted. */
959 emit_swap_insn (rtx insn, stack regstack, rtx reg)
963 int tmp, other_reg; /* swap regno temps */
964 rtx i1; /* the stack-reg insn prior to INSN */
965 rtx i1set = NULL_RTX; /* the SET rtx within I1 */
967 hard_regno = get_hard_regnum (regstack, reg);
969 if (hard_regno < FIRST_STACK_REG)
971 if (hard_regno == FIRST_STACK_REG)
974 other_reg = regstack->top - (hard_regno - FIRST_STACK_REG);
976 tmp = regstack->reg[other_reg];
977 regstack->reg[other_reg] = regstack->reg[regstack->top];
978 regstack->reg[regstack->top] = tmp;
980 /* Find the previous insn involving stack regs, but don't pass a
983 if (current_block && insn != BB_HEAD (current_block))
985 rtx tmp = PREV_INSN (insn);
986 rtx limit = PREV_INSN (BB_HEAD (current_block));
989 if (GET_CODE (tmp) == CODE_LABEL
990 || GET_CODE (tmp) == CALL_INSN
991 || NOTE_INSN_BASIC_BLOCK_P (tmp)
992 || (GET_CODE (tmp) == INSN
993 && stack_regs_mentioned (tmp)))
998 tmp = PREV_INSN (tmp);
1003 && (i1set = single_set (i1)) != NULL_RTX)
1005 rtx i1src = *get_true_reg (&SET_SRC (i1set));
1006 rtx i1dest = *get_true_reg (&SET_DEST (i1set));
1008 /* If the previous register stack push was from the reg we are to
1009 swap with, omit the swap. */
1011 if (GET_CODE (i1dest) == REG && REGNO (i1dest) == FIRST_STACK_REG
1012 && GET_CODE (i1src) == REG
1013 && REGNO (i1src) == (unsigned) hard_regno - 1
1014 && find_regno_note (i1, REG_DEAD, FIRST_STACK_REG) == NULL_RTX)
1017 /* If the previous insn wrote to the reg we are to swap with,
1020 if (GET_CODE (i1dest) == REG && REGNO (i1dest) == (unsigned) hard_regno
1021 && GET_CODE (i1src) == REG && REGNO (i1src) == FIRST_STACK_REG
1022 && find_regno_note (i1, REG_DEAD, FIRST_STACK_REG) == NULL_RTX)
1026 swap_rtx = gen_swapxf (FP_MODE_REG (hard_regno, XFmode),
1027 FP_MODE_REG (FIRST_STACK_REG, XFmode));
1030 emit_insn_after (swap_rtx, i1);
1031 else if (current_block)
1032 emit_insn_before (swap_rtx, BB_HEAD (current_block));
1034 emit_insn_before (swap_rtx, insn);
1037 /* Handle a move to or from a stack register in PAT, which is in INSN.
1038 REGSTACK is the current stack. Return whether a control flow insn
1039 was deleted in the process. */
1042 move_for_stack_reg (rtx insn, stack regstack, rtx pat)
1044 rtx *psrc = get_true_reg (&SET_SRC (pat));
1045 rtx *pdest = get_true_reg (&SET_DEST (pat));
1048 bool control_flow_insn_deleted = false;
1050 src = *psrc; dest = *pdest;
1052 if (STACK_REG_P (src) && STACK_REG_P (dest))
1054 /* Write from one stack reg to another. If SRC dies here, then
1055 just change the register mapping and delete the insn. */
1057 note = find_regno_note (insn, REG_DEAD, REGNO (src));
1062 /* If this is a no-op move, there must not be a REG_DEAD note. */
1063 if (REGNO (src) == REGNO (dest))
1066 for (i = regstack->top; i >= 0; i--)
1067 if (regstack->reg[i] == REGNO (src))
1070 /* The source must be live, and the dest must be dead. */
1071 if (i < 0 || get_hard_regnum (regstack, dest) >= FIRST_STACK_REG)
1074 /* It is possible that the dest is unused after this insn.
1075 If so, just pop the src. */
1077 if (find_regno_note (insn, REG_UNUSED, REGNO (dest)))
1078 emit_pop_insn (insn, regstack, src, EMIT_AFTER);
1081 regstack->reg[i] = REGNO (dest);
1082 SET_HARD_REG_BIT (regstack->reg_set, REGNO (dest));
1083 CLEAR_HARD_REG_BIT (regstack->reg_set, REGNO (src));
1086 control_flow_insn_deleted |= control_flow_insn_p (insn);
1088 return control_flow_insn_deleted;
1091 /* The source reg does not die. */
1093 /* If this appears to be a no-op move, delete it, or else it
1094 will confuse the machine description output patterns. But if
1095 it is REG_UNUSED, we must pop the reg now, as per-insn processing
1096 for REG_UNUSED will not work for deleted insns. */
1098 if (REGNO (src) == REGNO (dest))
1100 if (find_regno_note (insn, REG_UNUSED, REGNO (dest)))
1101 emit_pop_insn (insn, regstack, dest, EMIT_AFTER);
1103 control_flow_insn_deleted |= control_flow_insn_p (insn);
1105 return control_flow_insn_deleted;
1108 /* The destination ought to be dead. */
1109 if (get_hard_regnum (regstack, dest) >= FIRST_STACK_REG)
1112 replace_reg (psrc, get_hard_regnum (regstack, src));
1114 regstack->reg[++regstack->top] = REGNO (dest);
1115 SET_HARD_REG_BIT (regstack->reg_set, REGNO (dest));
1116 replace_reg (pdest, FIRST_STACK_REG);
1118 else if (STACK_REG_P (src))
1120 /* Save from a stack reg to MEM, or possibly integer reg. Since
1121 only top of stack may be saved, emit an exchange first if
1124 emit_swap_insn (insn, regstack, src);
1126 note = find_regno_note (insn, REG_DEAD, REGNO (src));
1129 replace_reg (&XEXP (note, 0), FIRST_STACK_REG);
1131 CLEAR_HARD_REG_BIT (regstack->reg_set, REGNO (src));
1133 else if ((GET_MODE (src) == XFmode)
1134 && regstack->top < REG_STACK_SIZE - 1)
1136 /* A 387 cannot write an XFmode value to a MEM without
1137 clobbering the source reg. The output code can handle
1138 this by reading back the value from the MEM.
1139 But it is more efficient to use a temp register if one is
1140 available. Push the source value here if the register
1141 stack is not full, and then write the value to memory via
1143 rtx push_rtx, push_insn;
1144 rtx top_stack_reg = FP_MODE_REG (FIRST_STACK_REG, GET_MODE (src));
1146 push_rtx = gen_movxf (top_stack_reg, top_stack_reg);
1147 push_insn = emit_insn_before (push_rtx, insn);
1148 REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_DEAD, top_stack_reg,
1152 replace_reg (psrc, FIRST_STACK_REG);
1154 else if (STACK_REG_P (dest))
1156 /* Load from MEM, or possibly integer REG or constant, into the
1157 stack regs. The actual target is always the top of the
1158 stack. The stack mapping is changed to reflect that DEST is
1159 now at top of stack. */
1161 /* The destination ought to be dead. */
1162 if (get_hard_regnum (regstack, dest) >= FIRST_STACK_REG)
1165 if (regstack->top >= REG_STACK_SIZE)
1168 regstack->reg[++regstack->top] = REGNO (dest);
1169 SET_HARD_REG_BIT (regstack->reg_set, REGNO (dest));
1170 replace_reg (pdest, FIRST_STACK_REG);
1175 return control_flow_insn_deleted;
1178 /* Swap the condition on a branch, if there is one. Return true if we
1179 found a condition to swap. False if the condition was not used as
1183 swap_rtx_condition_1 (rtx pat)
1188 if (COMPARISON_P (pat))
1190 PUT_CODE (pat, swap_condition (GET_CODE (pat)));
1195 fmt = GET_RTX_FORMAT (GET_CODE (pat));
1196 for (i = GET_RTX_LENGTH (GET_CODE (pat)) - 1; i >= 0; i--)
1202 for (j = XVECLEN (pat, i) - 1; j >= 0; j--)
1203 r |= swap_rtx_condition_1 (XVECEXP (pat, i, j));
1205 else if (fmt[i] == 'e')
1206 r |= swap_rtx_condition_1 (XEXP (pat, i));
1214 swap_rtx_condition (rtx insn)
1216 rtx pat = PATTERN (insn);
1218 /* We're looking for a single set to cc0 or an HImode temporary. */
1220 if (GET_CODE (pat) == SET
1221 && GET_CODE (SET_DEST (pat)) == REG
1222 && REGNO (SET_DEST (pat)) == FLAGS_REG)
1224 insn = next_flags_user (insn);
1225 if (insn == NULL_RTX)
1227 pat = PATTERN (insn);
1230 /* See if this is, or ends in, a fnstsw, aka unspec 9. If so, we're
1231 not doing anything with the cc value right now. We may be able to
1232 search for one though. */
1234 if (GET_CODE (pat) == SET
1235 && GET_CODE (SET_SRC (pat)) == UNSPEC
1236 && XINT (SET_SRC (pat), 1) == UNSPEC_FNSTSW)
1238 rtx dest = SET_DEST (pat);
1240 /* Search forward looking for the first use of this value.
1241 Stop at block boundaries. */
1242 while (insn != BB_END (current_block))
1244 insn = NEXT_INSN (insn);
1245 if (INSN_P (insn) && reg_mentioned_p (dest, insn))
1247 if (GET_CODE (insn) == CALL_INSN)
1251 /* So we've found the insn using this value. If it is anything
1252 other than sahf, aka unspec 10, or the value does not die
1253 (meaning we'd have to search further), then we must give up. */
1254 pat = PATTERN (insn);
1255 if (GET_CODE (pat) != SET
1256 || GET_CODE (SET_SRC (pat)) != UNSPEC
1257 || XINT (SET_SRC (pat), 1) != UNSPEC_SAHF
1258 || ! dead_or_set_p (insn, dest))
1261 /* Now we are prepared to handle this as a normal cc0 setter. */
1262 insn = next_flags_user (insn);
1263 if (insn == NULL_RTX)
1265 pat = PATTERN (insn);
1268 if (swap_rtx_condition_1 (pat))
1271 INSN_CODE (insn) = -1;
1272 if (recog_memoized (insn) == -1)
1274 /* In case the flags don't die here, recurse to try fix
1275 following user too. */
1276 else if (! dead_or_set_p (insn, ix86_flags_rtx))
1278 insn = next_flags_user (insn);
1279 if (!insn || !swap_rtx_condition (insn))
1284 swap_rtx_condition_1 (pat);
1292 /* Handle a comparison. Special care needs to be taken to avoid
1293 causing comparisons that a 387 cannot do correctly, such as EQ.
1295 Also, a pop insn may need to be emitted. The 387 does have an
1296 `fcompp' insn that can pop two regs, but it is sometimes too expensive
1297 to do this - a `fcomp' followed by a `fstpl %st(0)' may be easier to
1301 compare_for_stack_reg (rtx insn, stack regstack, rtx pat_src)
1304 rtx src1_note, src2_note;
1307 src1 = get_true_reg (&XEXP (pat_src, 0));
1308 src2 = get_true_reg (&XEXP (pat_src, 1));
1309 flags_user = next_flags_user (insn);
1311 /* ??? If fxch turns out to be cheaper than fstp, give priority to
1312 registers that die in this insn - move those to stack top first. */
1313 if ((! STACK_REG_P (*src1)
1314 || (STACK_REG_P (*src2)
1315 && get_hard_regnum (regstack, *src2) == FIRST_STACK_REG))
1316 && swap_rtx_condition (insn))
1319 temp = XEXP (pat_src, 0);
1320 XEXP (pat_src, 0) = XEXP (pat_src, 1);
1321 XEXP (pat_src, 1) = temp;
1323 src1 = get_true_reg (&XEXP (pat_src, 0));
1324 src2 = get_true_reg (&XEXP (pat_src, 1));
1326 INSN_CODE (insn) = -1;
1329 /* We will fix any death note later. */
1331 src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
1333 if (STACK_REG_P (*src2))
1334 src2_note = find_regno_note (insn, REG_DEAD, REGNO (*src2));
1336 src2_note = NULL_RTX;
1338 emit_swap_insn (insn, regstack, *src1);
1340 replace_reg (src1, FIRST_STACK_REG);
1342 if (STACK_REG_P (*src2))
1343 replace_reg (src2, get_hard_regnum (regstack, *src2));
1347 pop_stack (regstack, REGNO (XEXP (src1_note, 0)));
1348 replace_reg (&XEXP (src1_note, 0), FIRST_STACK_REG);
1351 /* If the second operand dies, handle that. But if the operands are
1352 the same stack register, don't bother, because only one death is
1353 needed, and it was just handled. */
1356 && ! (STACK_REG_P (*src1) && STACK_REG_P (*src2)
1357 && REGNO (*src1) == REGNO (*src2)))
1359 /* As a special case, two regs may die in this insn if src2 is
1360 next to top of stack and the top of stack also dies. Since
1361 we have already popped src1, "next to top of stack" is really
1362 at top (FIRST_STACK_REG) now. */
1364 if (get_hard_regnum (regstack, XEXP (src2_note, 0)) == FIRST_STACK_REG
1367 pop_stack (regstack, REGNO (XEXP (src2_note, 0)));
1368 replace_reg (&XEXP (src2_note, 0), FIRST_STACK_REG + 1);
1372 /* The 386 can only represent death of the first operand in
1373 the case handled above. In all other cases, emit a separate
1374 pop and remove the death note from here. */
1376 /* link_cc0_insns (insn); */
1378 remove_regno_note (insn, REG_DEAD, REGNO (XEXP (src2_note, 0)));
1380 emit_pop_insn (insn, regstack, XEXP (src2_note, 0),
1386 /* Substitute new registers in PAT, which is part of INSN. REGSTACK
1387 is the current register layout. Return whether a control flow insn
1388 was deleted in the process. */
1391 subst_stack_regs_pat (rtx insn, stack regstack, rtx pat)
1394 bool control_flow_insn_deleted = false;
1396 switch (GET_CODE (pat))
1399 /* Deaths in USE insns can happen in non optimizing compilation.
1400 Handle them by popping the dying register. */
1401 src = get_true_reg (&XEXP (pat, 0));
1402 if (STACK_REG_P (*src)
1403 && find_regno_note (insn, REG_DEAD, REGNO (*src)))
1405 emit_pop_insn (insn, regstack, *src, EMIT_AFTER);
1406 return control_flow_insn_deleted;
1408 /* ??? Uninitialized USE should not happen. */
1409 else if (get_hard_regnum (regstack, *src) == -1)
1417 dest = get_true_reg (&XEXP (pat, 0));
1418 if (STACK_REG_P (*dest))
1420 note = find_reg_note (insn, REG_DEAD, *dest);
1422 if (pat != PATTERN (insn))
1424 /* The fix_truncdi_1 pattern wants to be able to allocate
1425 it's own scratch register. It does this by clobbering
1426 an fp reg so that it is assured of an empty reg-stack
1427 register. If the register is live, kill it now.
1428 Remove the DEAD/UNUSED note so we don't try to kill it
1432 emit_pop_insn (insn, regstack, *dest, EMIT_BEFORE);
1435 note = find_reg_note (insn, REG_UNUSED, *dest);
1439 remove_note (insn, note);
1440 replace_reg (dest, FIRST_STACK_REG + 1);
1444 /* A top-level clobber with no REG_DEAD, and no hard-regnum
1445 indicates an uninitialized value. Because reload removed
1446 all other clobbers, this must be due to a function
1447 returning without a value. Load up a NaN. */
1450 && get_hard_regnum (regstack, *dest) == -1)
1452 pat = gen_rtx_SET (VOIDmode,
1453 FP_MODE_REG (REGNO (*dest), SFmode),
1455 PATTERN (insn) = pat;
1456 control_flow_insn_deleted |= move_for_stack_reg (insn, regstack, pat);
1458 if (! note && COMPLEX_MODE_P (GET_MODE (*dest))
1459 && get_hard_regnum (regstack, FP_MODE_REG (REGNO (*dest), DFmode)) == -1)
1461 pat = gen_rtx_SET (VOIDmode,
1462 FP_MODE_REG (REGNO (*dest) + 1, SFmode),
1464 PATTERN (insn) = pat;
1465 control_flow_insn_deleted |= move_for_stack_reg (insn, regstack, pat);
1474 rtx *src1 = (rtx *) 0, *src2;
1475 rtx src1_note, src2_note;
1478 dest = get_true_reg (&SET_DEST (pat));
1479 src = get_true_reg (&SET_SRC (pat));
1480 pat_src = SET_SRC (pat);
1482 /* See if this is a `movM' pattern, and handle elsewhere if so. */
1483 if (STACK_REG_P (*src)
1484 || (STACK_REG_P (*dest)
1485 && (GET_CODE (*src) == REG || GET_CODE (*src) == MEM
1486 || GET_CODE (*src) == CONST_DOUBLE)))
1488 control_flow_insn_deleted |= move_for_stack_reg (insn, regstack, pat);
1492 switch (GET_CODE (pat_src))
1495 compare_for_stack_reg (insn, regstack, pat_src);
1501 for (count = hard_regno_nregs[REGNO (*dest)][GET_MODE (*dest)];
1504 regstack->reg[++regstack->top] = REGNO (*dest) + count;
1505 SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest) + count);
1508 replace_reg (dest, FIRST_STACK_REG);
1512 /* This is a `tstM2' case. */
1513 if (*dest != cc0_rtx)
1519 case FLOAT_TRUNCATE:
1523 /* These insns only operate on the top of the stack. DEST might
1524 be cc0_rtx if we're processing a tstM pattern. Also, it's
1525 possible that the tstM case results in a REG_DEAD note on the
1529 src1 = get_true_reg (&XEXP (pat_src, 0));
1531 emit_swap_insn (insn, regstack, *src1);
1533 src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
1535 if (STACK_REG_P (*dest))
1536 replace_reg (dest, FIRST_STACK_REG);
1540 replace_reg (&XEXP (src1_note, 0), FIRST_STACK_REG);
1542 CLEAR_HARD_REG_BIT (regstack->reg_set, REGNO (*src1));
1545 replace_reg (src1, FIRST_STACK_REG);
1550 /* On i386, reversed forms of subM3 and divM3 exist for
1551 MODE_FLOAT, so the same code that works for addM3 and mulM3
1555 /* These insns can accept the top of stack as a destination
1556 from a stack reg or mem, or can use the top of stack as a
1557 source and some other stack register (possibly top of stack)
1558 as a destination. */
1560 src1 = get_true_reg (&XEXP (pat_src, 0));
1561 src2 = get_true_reg (&XEXP (pat_src, 1));
1563 /* We will fix any death note later. */
1565 if (STACK_REG_P (*src1))
1566 src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
1568 src1_note = NULL_RTX;
1569 if (STACK_REG_P (*src2))
1570 src2_note = find_regno_note (insn, REG_DEAD, REGNO (*src2));
1572 src2_note = NULL_RTX;
1574 /* If either operand is not a stack register, then the dest
1575 must be top of stack. */
1577 if (! STACK_REG_P (*src1) || ! STACK_REG_P (*src2))
1578 emit_swap_insn (insn, regstack, *dest);
1581 /* Both operands are REG. If neither operand is already
1582 at the top of stack, choose to make the one that is the dest
1583 the new top of stack. */
1585 int src1_hard_regnum, src2_hard_regnum;
1587 src1_hard_regnum = get_hard_regnum (regstack, *src1);
1588 src2_hard_regnum = get_hard_regnum (regstack, *src2);
1589 if (src1_hard_regnum == -1 || src2_hard_regnum == -1)
1592 if (src1_hard_regnum != FIRST_STACK_REG
1593 && src2_hard_regnum != FIRST_STACK_REG)
1594 emit_swap_insn (insn, regstack, *dest);
1597 if (STACK_REG_P (*src1))
1598 replace_reg (src1, get_hard_regnum (regstack, *src1));
1599 if (STACK_REG_P (*src2))
1600 replace_reg (src2, get_hard_regnum (regstack, *src2));
1604 rtx src1_reg = XEXP (src1_note, 0);
1606 /* If the register that dies is at the top of stack, then
1607 the destination is somewhere else - merely substitute it.
1608 But if the reg that dies is not at top of stack, then
1609 move the top of stack to the dead reg, as though we had
1610 done the insn and then a store-with-pop. */
1612 if (REGNO (src1_reg) == regstack->reg[regstack->top])
1614 SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
1615 replace_reg (dest, get_hard_regnum (regstack, *dest));
1619 int regno = get_hard_regnum (regstack, src1_reg);
1621 SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
1622 replace_reg (dest, regno);
1624 regstack->reg[regstack->top - (regno - FIRST_STACK_REG)]
1625 = regstack->reg[regstack->top];
1628 CLEAR_HARD_REG_BIT (regstack->reg_set,
1629 REGNO (XEXP (src1_note, 0)));
1630 replace_reg (&XEXP (src1_note, 0), FIRST_STACK_REG);
1635 rtx src2_reg = XEXP (src2_note, 0);
1636 if (REGNO (src2_reg) == regstack->reg[regstack->top])
1638 SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
1639 replace_reg (dest, get_hard_regnum (regstack, *dest));
1643 int regno = get_hard_regnum (regstack, src2_reg);
1645 SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
1646 replace_reg (dest, regno);
1648 regstack->reg[regstack->top - (regno - FIRST_STACK_REG)]
1649 = regstack->reg[regstack->top];
1652 CLEAR_HARD_REG_BIT (regstack->reg_set,
1653 REGNO (XEXP (src2_note, 0)));
1654 replace_reg (&XEXP (src2_note, 0), FIRST_STACK_REG);
1659 SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
1660 replace_reg (dest, get_hard_regnum (regstack, *dest));
1663 /* Keep operand 1 matching with destination. */
1664 if (COMMUTATIVE_ARITH_P (pat_src)
1665 && REG_P (*src1) && REG_P (*src2)
1666 && REGNO (*src1) != REGNO (*dest))
1668 int tmp = REGNO (*src1);
1669 replace_reg (src1, REGNO (*src2));
1670 replace_reg (src2, tmp);
1675 switch (XINT (pat_src, 1))
1679 case UNSPEC_FRNDINT:
1681 /* These insns only operate on the top of the stack. */
1683 src1 = get_true_reg (&XVECEXP (pat_src, 0, 0));
1685 emit_swap_insn (insn, regstack, *src1);
1687 src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
1689 if (STACK_REG_P (*dest))
1690 replace_reg (dest, FIRST_STACK_REG);
1694 replace_reg (&XEXP (src1_note, 0), FIRST_STACK_REG);
1696 CLEAR_HARD_REG_BIT (regstack->reg_set, REGNO (*src1));
1699 replace_reg (src1, FIRST_STACK_REG);
1705 /* These insns operate on the top two stack slots. */
1707 src1 = get_true_reg (&XVECEXP (pat_src, 0, 0));
1708 src2 = get_true_reg (&XVECEXP (pat_src, 0, 1));
1710 src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
1711 src2_note = find_regno_note (insn, REG_DEAD, REGNO (*src2));
1714 struct stack_def temp_stack;
1715 int regno, j, k, temp;
1717 temp_stack = *regstack;
1719 /* Place operand 1 at the top of stack. */
1720 regno = get_hard_regnum (&temp_stack, *src1);
1723 if (regno != FIRST_STACK_REG)
1725 k = temp_stack.top - (regno - FIRST_STACK_REG);
1728 temp = temp_stack.reg[k];
1729 temp_stack.reg[k] = temp_stack.reg[j];
1730 temp_stack.reg[j] = temp;
1733 /* Place operand 2 next on the stack. */
1734 regno = get_hard_regnum (&temp_stack, *src2);
1737 if (regno != FIRST_STACK_REG + 1)
1739 k = temp_stack.top - (regno - FIRST_STACK_REG);
1740 j = temp_stack.top - 1;
1742 temp = temp_stack.reg[k];
1743 temp_stack.reg[k] = temp_stack.reg[j];
1744 temp_stack.reg[j] = temp;
1747 change_stack (insn, regstack, &temp_stack, EMIT_BEFORE);
1750 replace_reg (src1, FIRST_STACK_REG);
1751 replace_reg (src2, FIRST_STACK_REG + 1);
1754 replace_reg (&XEXP (src1_note, 0), FIRST_STACK_REG);
1756 replace_reg (&XEXP (src2_note, 0), FIRST_STACK_REG + 1);
1758 /* Pop both input operands from the stack. */
1759 CLEAR_HARD_REG_BIT (regstack->reg_set,
1760 regstack->reg[regstack->top]);
1761 CLEAR_HARD_REG_BIT (regstack->reg_set,
1762 regstack->reg[regstack->top - 1]);
1765 /* Push the result back onto the stack. */
1766 regstack->reg[++regstack->top] = REGNO (*dest);
1767 SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
1768 replace_reg (dest, FIRST_STACK_REG);
1772 /* (unspec [(unspec [(compare)] UNSPEC_FNSTSW)] UNSPEC_SAHF)
1773 The combination matches the PPRO fcomi instruction. */
1775 pat_src = XVECEXP (pat_src, 0, 0);
1776 if (GET_CODE (pat_src) != UNSPEC
1777 || XINT (pat_src, 1) != UNSPEC_FNSTSW)
1782 /* Combined fcomp+fnstsw generated for doing well with
1783 CSE. When optimizing this would have been broken
1786 pat_src = XVECEXP (pat_src, 0, 0);
1787 if (GET_CODE (pat_src) != COMPARE)
1790 compare_for_stack_reg (insn, regstack, pat_src);
1799 /* This insn requires the top of stack to be the destination. */
1801 src1 = get_true_reg (&XEXP (pat_src, 1));
1802 src2 = get_true_reg (&XEXP (pat_src, 2));
1804 src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
1805 src2_note = find_regno_note (insn, REG_DEAD, REGNO (*src2));
1807 /* If the comparison operator is an FP comparison operator,
1808 it is handled correctly by compare_for_stack_reg () who
1809 will move the destination to the top of stack. But if the
1810 comparison operator is not an FP comparison operator, we
1811 have to handle it here. */
1812 if (get_hard_regnum (regstack, *dest) >= FIRST_STACK_REG
1813 && REGNO (*dest) != regstack->reg[regstack->top])
1815 /* In case one of operands is the top of stack and the operands
1816 dies, it is safe to make it the destination operand by
1817 reversing the direction of cmove and avoid fxch. */
1818 if ((REGNO (*src1) == regstack->reg[regstack->top]
1820 || (REGNO (*src2) == regstack->reg[regstack->top]
1823 int idx1 = (get_hard_regnum (regstack, *src1)
1825 int idx2 = (get_hard_regnum (regstack, *src2)
1828 /* Make reg-stack believe that the operands are already
1829 swapped on the stack */
1830 regstack->reg[regstack->top - idx1] = REGNO (*src2);
1831 regstack->reg[regstack->top - idx2] = REGNO (*src1);
1833 /* Reverse condition to compensate the operand swap.
1834 i386 do have comparison always reversible. */
1835 PUT_CODE (XEXP (pat_src, 0),
1836 reversed_comparison_code (XEXP (pat_src, 0), insn));
1839 emit_swap_insn (insn, regstack, *dest);
1847 src_note[1] = src1_note;
1848 src_note[2] = src2_note;
1850 if (STACK_REG_P (*src1))
1851 replace_reg (src1, get_hard_regnum (regstack, *src1));
1852 if (STACK_REG_P (*src2))
1853 replace_reg (src2, get_hard_regnum (regstack, *src2));
1855 for (i = 1; i <= 2; i++)
1858 int regno = REGNO (XEXP (src_note[i], 0));
1860 /* If the register that dies is not at the top of
1861 stack, then move the top of stack to the dead reg */
1862 if (regno != regstack->reg[regstack->top])
1864 remove_regno_note (insn, REG_DEAD, regno);
1865 emit_pop_insn (insn, regstack, XEXP (src_note[i], 0),
1869 /* Top of stack never dies, as it is the
1875 /* Make dest the top of stack. Add dest to regstack if
1877 if (get_hard_regnum (regstack, *dest) < FIRST_STACK_REG)
1878 regstack->reg[++regstack->top] = REGNO (*dest);
1879 SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
1880 replace_reg (dest, FIRST_STACK_REG);
1893 return control_flow_insn_deleted;
1896 /* Substitute hard regnums for any stack regs in INSN, which has
1897 N_INPUTS inputs and N_OUTPUTS outputs. REGSTACK is the stack info
1898 before the insn, and is updated with changes made here.
1900 There are several requirements and assumptions about the use of
1901 stack-like regs in asm statements. These rules are enforced by
1902 record_asm_stack_regs; see comments there for details. Any
1903 asm_operands left in the RTL at this point may be assume to meet the
1904 requirements, since record_asm_stack_regs removes any problem asm. */
1907 subst_asm_stack_regs (rtx insn, stack regstack)
1909 rtx body = PATTERN (insn);
1912 rtx *note_reg; /* Array of note contents */
1913 rtx **note_loc; /* Address of REG field of each note */
1914 enum reg_note *note_kind; /* The type of each note */
1916 rtx *clobber_reg = 0;
1917 rtx **clobber_loc = 0;
1919 struct stack_def temp_stack;
1924 int n_inputs, n_outputs;
1926 if (! check_asm_stack_operands (insn))
1929 /* Find out what the constraints required. If no constraint
1930 alternative matches, that is a compiler bug: we should have caught
1931 such an insn in check_asm_stack_operands. */
1932 extract_insn (insn);
1933 constrain_operands (1);
1934 alt = which_alternative;
1936 preprocess_constraints ();
1938 n_inputs = get_asm_operand_n_inputs (body);
1939 n_outputs = recog_data.n_operands - n_inputs;
1944 /* Strip SUBREGs here to make the following code simpler. */
1945 for (i = 0; i < recog_data.n_operands; i++)
1946 if (GET_CODE (recog_data.operand[i]) == SUBREG
1947 && GET_CODE (SUBREG_REG (recog_data.operand[i])) == REG)
1949 recog_data.operand_loc[i] = & SUBREG_REG (recog_data.operand[i]);
1950 recog_data.operand[i] = SUBREG_REG (recog_data.operand[i]);
1953 /* Set up NOTE_REG, NOTE_LOC and NOTE_KIND. */
1955 for (i = 0, note = REG_NOTES (insn); note; note = XEXP (note, 1))
1958 note_reg = alloca (i * sizeof (rtx));
1959 note_loc = alloca (i * sizeof (rtx *));
1960 note_kind = alloca (i * sizeof (enum reg_note));
1963 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
1965 rtx reg = XEXP (note, 0);
1966 rtx *loc = & XEXP (note, 0);
1968 if (GET_CODE (reg) == SUBREG && GET_CODE (SUBREG_REG (reg)) == REG)
1970 loc = & SUBREG_REG (reg);
1971 reg = SUBREG_REG (reg);
1974 if (STACK_REG_P (reg)
1975 && (REG_NOTE_KIND (note) == REG_DEAD
1976 || REG_NOTE_KIND (note) == REG_UNUSED))
1978 note_reg[n_notes] = reg;
1979 note_loc[n_notes] = loc;
1980 note_kind[n_notes] = REG_NOTE_KIND (note);
1985 /* Set up CLOBBER_REG and CLOBBER_LOC. */
1989 if (GET_CODE (body) == PARALLEL)
1991 clobber_reg = alloca (XVECLEN (body, 0) * sizeof (rtx));
1992 clobber_loc = alloca (XVECLEN (body, 0) * sizeof (rtx *));
1994 for (i = 0; i < XVECLEN (body, 0); i++)
1995 if (GET_CODE (XVECEXP (body, 0, i)) == CLOBBER)
1997 rtx clobber = XVECEXP (body, 0, i);
1998 rtx reg = XEXP (clobber, 0);
1999 rtx *loc = & XEXP (clobber, 0);
2001 if (GET_CODE (reg) == SUBREG && GET_CODE (SUBREG_REG (reg)) == REG)
2003 loc = & SUBREG_REG (reg);
2004 reg = SUBREG_REG (reg);
2007 if (STACK_REG_P (reg))
2009 clobber_reg[n_clobbers] = reg;
2010 clobber_loc[n_clobbers] = loc;
2016 temp_stack = *regstack;
2018 /* Put the input regs into the desired place in TEMP_STACK. */
2020 for (i = n_outputs; i < n_outputs + n_inputs; i++)
2021 if (STACK_REG_P (recog_data.operand[i])
2022 && reg_class_subset_p (recog_op_alt[i][alt].class,
2024 && recog_op_alt[i][alt].class != FLOAT_REGS)
2026 /* If an operand needs to be in a particular reg in
2027 FLOAT_REGS, the constraint was either 't' or 'u'. Since
2028 these constraints are for single register classes, and
2029 reload guaranteed that operand[i] is already in that class,
2030 we can just use REGNO (recog_data.operand[i]) to know which
2031 actual reg this operand needs to be in. */
2033 int regno = get_hard_regnum (&temp_stack, recog_data.operand[i]);
2038 if ((unsigned int) regno != REGNO (recog_data.operand[i]))
2040 /* recog_data.operand[i] is not in the right place. Find
2041 it and swap it with whatever is already in I's place.
2042 K is where recog_data.operand[i] is now. J is where it
2046 k = temp_stack.top - (regno - FIRST_STACK_REG);
2048 - (REGNO (recog_data.operand[i]) - FIRST_STACK_REG));
2050 temp = temp_stack.reg[k];
2051 temp_stack.reg[k] = temp_stack.reg[j];
2052 temp_stack.reg[j] = temp;
2056 /* Emit insns before INSN to make sure the reg-stack is in the right
2059 change_stack (insn, regstack, &temp_stack, EMIT_BEFORE);
2061 /* Make the needed input register substitutions. Do death notes and
2062 clobbers too, because these are for inputs, not outputs. */
2064 for (i = n_outputs; i < n_outputs + n_inputs; i++)
2065 if (STACK_REG_P (recog_data.operand[i]))
2067 int regnum = get_hard_regnum (regstack, recog_data.operand[i]);
2072 replace_reg (recog_data.operand_loc[i], regnum);
2075 for (i = 0; i < n_notes; i++)
2076 if (note_kind[i] == REG_DEAD)
2078 int regnum = get_hard_regnum (regstack, note_reg[i]);
2083 replace_reg (note_loc[i], regnum);
2086 for (i = 0; i < n_clobbers; i++)
2088 /* It's OK for a CLOBBER to reference a reg that is not live.
2089 Don't try to replace it in that case. */
2090 int regnum = get_hard_regnum (regstack, clobber_reg[i]);
2094 /* Sigh - clobbers always have QImode. But replace_reg knows
2095 that these regs can't be MODE_INT and will abort. Just put
2096 the right reg there without calling replace_reg. */
2098 *clobber_loc[i] = FP_MODE_REG (regnum, DFmode);
2102 /* Now remove from REGSTACK any inputs that the asm implicitly popped. */
2104 for (i = n_outputs; i < n_outputs + n_inputs; i++)
2105 if (STACK_REG_P (recog_data.operand[i]))
2107 /* An input reg is implicitly popped if it is tied to an
2108 output, or if there is a CLOBBER for it. */
2111 for (j = 0; j < n_clobbers; j++)
2112 if (operands_match_p (clobber_reg[j], recog_data.operand[i]))
2115 if (j < n_clobbers || recog_op_alt[i][alt].matches >= 0)
2117 /* recog_data.operand[i] might not be at the top of stack.
2118 But that's OK, because all we need to do is pop the
2119 right number of regs off of the top of the reg-stack.
2120 record_asm_stack_regs guaranteed that all implicitly
2121 popped regs were grouped at the top of the reg-stack. */
2123 CLEAR_HARD_REG_BIT (regstack->reg_set,
2124 regstack->reg[regstack->top]);
2129 /* Now add to REGSTACK any outputs that the asm implicitly pushed.
2130 Note that there isn't any need to substitute register numbers.
2131 ??? Explain why this is true. */
2133 for (i = LAST_STACK_REG; i >= FIRST_STACK_REG; i--)
2135 /* See if there is an output for this hard reg. */
2138 for (j = 0; j < n_outputs; j++)
2139 if (STACK_REG_P (recog_data.operand[j])
2140 && REGNO (recog_data.operand[j]) == (unsigned) i)
2142 regstack->reg[++regstack->top] = i;
2143 SET_HARD_REG_BIT (regstack->reg_set, i);
2148 /* Now emit a pop insn for any REG_UNUSED output, or any REG_DEAD
2149 input that the asm didn't implicitly pop. If the asm didn't
2150 implicitly pop an input reg, that reg will still be live.
2152 Note that we can't use find_regno_note here: the register numbers
2153 in the death notes have already been substituted. */
2155 for (i = 0; i < n_outputs; i++)
2156 if (STACK_REG_P (recog_data.operand[i]))
2160 for (j = 0; j < n_notes; j++)
2161 if (REGNO (recog_data.operand[i]) == REGNO (note_reg[j])
2162 && note_kind[j] == REG_UNUSED)
2164 insn = emit_pop_insn (insn, regstack, recog_data.operand[i],
2170 for (i = n_outputs; i < n_outputs + n_inputs; i++)
2171 if (STACK_REG_P (recog_data.operand[i]))
2175 for (j = 0; j < n_notes; j++)
2176 if (REGNO (recog_data.operand[i]) == REGNO (note_reg[j])
2177 && note_kind[j] == REG_DEAD
2178 && TEST_HARD_REG_BIT (regstack->reg_set,
2179 REGNO (recog_data.operand[i])))
2181 insn = emit_pop_insn (insn, regstack, recog_data.operand[i],
2188 /* Substitute stack hard reg numbers for stack virtual registers in
2189 INSN. Non-stack register numbers are not changed. REGSTACK is the
2190 current stack content. Insns may be emitted as needed to arrange the
2191 stack for the 387 based on the contents of the insn. Return whether
2192 a control flow insn was deleted in the process. */
2195 subst_stack_regs (rtx insn, stack regstack)
2197 rtx *note_link, note;
2198 bool control_flow_insn_deleted = false;
2201 if (GET_CODE (insn) == CALL_INSN)
2203 int top = regstack->top;
2205 /* If there are any floating point parameters to be passed in
2206 registers for this call, make sure they are in the right
2211 straighten_stack (PREV_INSN (insn), regstack);
2213 /* Now mark the arguments as dead after the call. */
2215 while (regstack->top >= 0)
2217 CLEAR_HARD_REG_BIT (regstack->reg_set, FIRST_STACK_REG + regstack->top);
2223 /* Do the actual substitution if any stack regs are mentioned.
2224 Since we only record whether entire insn mentions stack regs, and
2225 subst_stack_regs_pat only works for patterns that contain stack regs,
2226 we must check each pattern in a parallel here. A call_value_pop could
2229 if (stack_regs_mentioned (insn))
2231 int n_operands = asm_noperands (PATTERN (insn));
2232 if (n_operands >= 0)
2234 /* This insn is an `asm' with operands. Decode the operands,
2235 decide how many are inputs, and do register substitution.
2236 Any REG_UNUSED notes will be handled by subst_asm_stack_regs. */
2238 subst_asm_stack_regs (insn, regstack);
2239 return control_flow_insn_deleted;
2242 if (GET_CODE (PATTERN (insn)) == PARALLEL)
2243 for (i = 0; i < XVECLEN (PATTERN (insn), 0); i++)
2245 if (stack_regs_mentioned_p (XVECEXP (PATTERN (insn), 0, i)))
2247 if (GET_CODE (XVECEXP (PATTERN (insn), 0, i)) == CLOBBER)
2248 XVECEXP (PATTERN (insn), 0, i)
2249 = shallow_copy_rtx (XVECEXP (PATTERN (insn), 0, i));
2250 control_flow_insn_deleted
2251 |= subst_stack_regs_pat (insn, regstack,
2252 XVECEXP (PATTERN (insn), 0, i));
2256 control_flow_insn_deleted
2257 |= subst_stack_regs_pat (insn, regstack, PATTERN (insn));
2260 /* subst_stack_regs_pat may have deleted a no-op insn. If so, any
2261 REG_UNUSED will already have been dealt with, so just return. */
2263 if (GET_CODE (insn) == NOTE || INSN_DELETED_P (insn))
2264 return control_flow_insn_deleted;
2266 /* If there is a REG_UNUSED note on a stack register on this insn,
2267 the indicated reg must be popped. The REG_UNUSED note is removed,
2268 since the form of the newly emitted pop insn references the reg,
2269 making it no longer `unset'. */
2271 note_link = ®_NOTES (insn);
2272 for (note = *note_link; note; note = XEXP (note, 1))
2273 if (REG_NOTE_KIND (note) == REG_UNUSED && STACK_REG_P (XEXP (note, 0)))
2275 *note_link = XEXP (note, 1);
2276 insn = emit_pop_insn (insn, regstack, XEXP (note, 0), EMIT_AFTER);
2279 note_link = &XEXP (note, 1);
2281 return control_flow_insn_deleted;
2284 /* Change the organization of the stack so that it fits a new basic
2285 block. Some registers might have to be popped, but there can never be
2286 a register live in the new block that is not now live.
2288 Insert any needed insns before or after INSN, as indicated by
2289 WHERE. OLD is the original stack layout, and NEW is the desired
2290 form. OLD is updated to reflect the code emitted, ie, it will be
2291 the same as NEW upon return.
2293 This function will not preserve block_end[]. But that information
2294 is no longer needed once this has executed. */
2297 change_stack (rtx insn, stack old, stack new, enum emit_where where)
2302 /* We will be inserting new insns "backwards". If we are to insert
2303 after INSN, find the next insn, and insert before it. */
2305 if (where == EMIT_AFTER)
2307 if (current_block && BB_END (current_block) == insn)
2309 insn = NEXT_INSN (insn);
2312 /* Pop any registers that are not needed in the new block. */
2314 for (reg = old->top; reg >= 0; reg--)
2315 if (! TEST_HARD_REG_BIT (new->reg_set, old->reg[reg]))
2316 emit_pop_insn (insn, old, FP_MODE_REG (old->reg[reg], DFmode),
2321 /* If the new block has never been processed, then it can inherit
2322 the old stack order. */
2324 new->top = old->top;
2325 memcpy (new->reg, old->reg, sizeof (new->reg));
2329 /* This block has been entered before, and we must match the
2330 previously selected stack order. */
2332 /* By now, the only difference should be the order of the stack,
2333 not their depth or liveliness. */
2335 GO_IF_HARD_REG_EQUAL (old->reg_set, new->reg_set, win);
2338 if (old->top != new->top)
2341 /* If the stack is not empty (new->top != -1), loop here emitting
2342 swaps until the stack is correct.
2344 The worst case number of swaps emitted is N + 2, where N is the
2345 depth of the stack. In some cases, the reg at the top of
2346 stack may be correct, but swapped anyway in order to fix
2347 other regs. But since we never swap any other reg away from
2348 its correct slot, this algorithm will converge. */
2353 /* Swap the reg at top of stack into the position it is
2354 supposed to be in, until the correct top of stack appears. */
2356 while (old->reg[old->top] != new->reg[new->top])
2358 for (reg = new->top; reg >= 0; reg--)
2359 if (new->reg[reg] == old->reg[old->top])
2365 emit_swap_insn (insn, old,
2366 FP_MODE_REG (old->reg[reg], DFmode));
2369 /* See if any regs remain incorrect. If so, bring an
2370 incorrect reg to the top of stack, and let the while loop
2373 for (reg = new->top; reg >= 0; reg--)
2374 if (new->reg[reg] != old->reg[reg])
2376 emit_swap_insn (insn, old,
2377 FP_MODE_REG (old->reg[reg], DFmode));
2382 /* At this point there must be no differences. */
2384 for (reg = old->top; reg >= 0; reg--)
2385 if (old->reg[reg] != new->reg[reg])
2390 BB_END (current_block) = PREV_INSN (insn);
2393 /* Print stack configuration. */
2396 print_stack (FILE *file, stack s)
2402 fprintf (file, "uninitialized\n");
2403 else if (s->top == -1)
2404 fprintf (file, "empty\n");
2409 for (i = 0; i <= s->top; ++i)
2410 fprintf (file, "%d ", s->reg[i]);
2411 fputs ("]\n", file);
2415 /* This function was doing life analysis. We now let the regular live
2416 code do it's job, so we only need to check some extra invariants
2417 that reg-stack expects. Primary among these being that all registers
2418 are initialized before use.
2420 The function returns true when code was emitted to CFG edges and
2421 commit_edge_insertions needs to be called. */
2424 convert_regs_entry (void)
2430 FOR_EACH_BB_REVERSE (block)
2432 block_info bi = BLOCK_INFO (block);
2435 /* Set current register status at last instruction `uninitialized'. */
2436 bi->stack_in.top = -2;
2438 /* Copy live_at_end and live_at_start into temporaries. */
2439 for (reg = FIRST_STACK_REG; reg <= LAST_STACK_REG; reg++)
2441 if (REGNO_REG_SET_P (block->global_live_at_end, reg))
2442 SET_HARD_REG_BIT (bi->out_reg_set, reg);
2443 if (REGNO_REG_SET_P (block->global_live_at_start, reg))
2444 SET_HARD_REG_BIT (bi->stack_in.reg_set, reg);
2448 /* Load something into each stack register live at function entry.
2449 Such live registers can be caused by uninitialized variables or
2450 functions not returning values on all paths. In order to keep
2451 the push/pop code happy, and to not scrog the register stack, we
2452 must put something in these registers. Use a QNaN.
2454 Note that we are inserting converted code here. This code is
2455 never seen by the convert_regs pass. */
2457 for (e = ENTRY_BLOCK_PTR->succ; e ; e = e->succ_next)
2459 basic_block block = e->dest;
2460 block_info bi = BLOCK_INFO (block);
2463 for (reg = LAST_STACK_REG; reg >= FIRST_STACK_REG; --reg)
2464 if (TEST_HARD_REG_BIT (bi->stack_in.reg_set, reg))
2468 bi->stack_in.reg[++top] = reg;
2470 init = gen_rtx_SET (VOIDmode,
2471 FP_MODE_REG (FIRST_STACK_REG, SFmode),
2473 insert_insn_on_edge (init, e);
2477 bi->stack_in.top = top;
2483 /* Construct the desired stack for function exit. This will either
2484 be `empty', or the function return value at top-of-stack. */
2487 convert_regs_exit (void)
2489 int value_reg_low, value_reg_high;
2493 retvalue = stack_result (current_function_decl);
2494 value_reg_low = value_reg_high = -1;
2497 value_reg_low = REGNO (retvalue);
2498 value_reg_high = value_reg_low
2499 + hard_regno_nregs[value_reg_low][GET_MODE (retvalue)] - 1;
2502 output_stack = &BLOCK_INFO (EXIT_BLOCK_PTR)->stack_in;
2503 if (value_reg_low == -1)
2504 output_stack->top = -1;
2509 output_stack->top = value_reg_high - value_reg_low;
2510 for (reg = value_reg_low; reg <= value_reg_high; ++reg)
2512 output_stack->reg[value_reg_high - reg] = reg;
2513 SET_HARD_REG_BIT (output_stack->reg_set, reg);
2518 /* Adjust the stack of this block on exit to match the stack of the
2519 target block, or copy stack info into the stack of the successor
2520 of the successor hasn't been processed yet. */
2522 compensate_edge (edge e, FILE *file)
2524 basic_block block = e->src, target = e->dest;
2525 block_info bi = BLOCK_INFO (block);
2526 struct stack_def regstack, tmpstack;
2527 stack target_stack = &BLOCK_INFO (target)->stack_in;
2530 current_block = block;
2531 regstack = bi->stack_out;
2533 fprintf (file, "Edge %d->%d: ", block->index, target->index);
2535 if (target_stack->top == -2)
2537 /* The target block hasn't had a stack order selected.
2538 We need merely ensure that no pops are needed. */
2539 for (reg = regstack.top; reg >= 0; --reg)
2540 if (!TEST_HARD_REG_BIT (target_stack->reg_set, regstack.reg[reg]))
2546 fprintf (file, "new block; copying stack position\n");
2548 /* change_stack kills values in regstack. */
2549 tmpstack = regstack;
2551 change_stack (BB_END (block), &tmpstack, target_stack, EMIT_AFTER);
2556 fprintf (file, "new block; pops needed\n");
2560 if (target_stack->top == regstack.top)
2562 for (reg = target_stack->top; reg >= 0; --reg)
2563 if (target_stack->reg[reg] != regstack.reg[reg])
2569 fprintf (file, "no changes needed\n");
2576 fprintf (file, "correcting stack to ");
2577 print_stack (file, target_stack);
2581 /* Care for non-call EH edges specially. The normal return path have
2582 values in registers. These will be popped en masse by the unwind
2584 if ((e->flags & (EDGE_EH | EDGE_ABNORMAL_CALL)) == EDGE_EH)
2585 target_stack->top = -1;
2587 /* Other calls may appear to have values live in st(0), but the
2588 abnormal return path will not have actually loaded the values. */
2589 else if (e->flags & EDGE_ABNORMAL_CALL)
2591 /* Assert that the lifetimes are as we expect -- one value
2592 live at st(0) on the end of the source block, and no
2593 values live at the beginning of the destination block. */
2596 CLEAR_HARD_REG_SET (tmp);
2597 GO_IF_HARD_REG_EQUAL (target_stack->reg_set, tmp, eh1);
2601 /* We are sure that there is st(0) live, otherwise we won't compensate.
2602 For complex return values, we may have st(1) live as well. */
2603 SET_HARD_REG_BIT (tmp, FIRST_STACK_REG);
2604 if (TEST_HARD_REG_BIT (regstack.reg_set, FIRST_STACK_REG + 1))
2605 SET_HARD_REG_BIT (tmp, FIRST_STACK_REG + 1);
2606 GO_IF_HARD_REG_EQUAL (regstack.reg_set, tmp, eh2);
2610 target_stack->top = -1;
2613 /* It is better to output directly to the end of the block
2614 instead of to the edge, because emit_swap can do minimal
2615 insn scheduling. We can do this when there is only one
2616 edge out, and it is not abnormal. */
2617 else if (block->succ->succ_next == NULL && !(e->flags & EDGE_ABNORMAL))
2619 /* change_stack kills values in regstack. */
2620 tmpstack = regstack;
2622 change_stack (BB_END (block), &tmpstack, target_stack,
2623 (GET_CODE (BB_END (block)) == JUMP_INSN
2624 ? EMIT_BEFORE : EMIT_AFTER));
2630 /* We don't support abnormal edges. Global takes care to
2631 avoid any live register across them, so we should never
2632 have to insert instructions on such edges. */
2633 if (e->flags & EDGE_ABNORMAL)
2636 current_block = NULL;
2639 /* ??? change_stack needs some point to emit insns after. */
2640 after = emit_note (NOTE_INSN_DELETED);
2642 tmpstack = regstack;
2643 change_stack (after, &tmpstack, target_stack, EMIT_BEFORE);
2648 insert_insn_on_edge (seq, e);
2654 /* Convert stack register references in one block. */
2657 convert_regs_1 (FILE *file, basic_block block)
2659 struct stack_def regstack;
2660 block_info bi = BLOCK_INFO (block);
2661 int deleted, inserted, reg;
2663 edge e, beste = NULL;
2664 bool control_flow_insn_deleted = false;
2668 any_malformed_asm = false;
2670 /* Find the edge we will copy stack from. It should be the most frequent
2671 one as it will get cheapest after compensation code is generated,
2672 if multiple such exists, take one with largest count, prefer critical
2673 one (as splitting critical edges is more expensive), or one with lowest
2674 index, to avoid random changes with different orders of the edges. */
2675 for (e = block->pred; e ; e = e->pred_next)
2677 if (e->flags & EDGE_DFS_BACK)
2681 else if (EDGE_FREQUENCY (beste) < EDGE_FREQUENCY (e))
2683 else if (EDGE_FREQUENCY (beste) > EDGE_FREQUENCY (e))
2685 else if (beste->count < e->count)
2687 else if (beste->count > e->count)
2689 else if ((EDGE_CRITICAL_P (e) != 0)
2690 != (EDGE_CRITICAL_P (beste) != 0))
2692 if (EDGE_CRITICAL_P (e))
2695 else if (e->src->index < beste->src->index)
2699 /* Initialize stack at block entry. */
2700 if (bi->stack_in.top == -2)
2703 inserted |= compensate_edge (beste, file);
2706 /* No predecessors. Create an arbitrary input stack. */
2709 bi->stack_in.top = -1;
2710 for (reg = LAST_STACK_REG; reg >= FIRST_STACK_REG; --reg)
2711 if (TEST_HARD_REG_BIT (bi->stack_in.reg_set, reg))
2712 bi->stack_in.reg[++bi->stack_in.top] = reg;
2716 /* Entry blocks do have stack already initialized. */
2719 current_block = block;
2723 fprintf (file, "\nBasic block %d\nInput stack: ", block->index);
2724 print_stack (file, &bi->stack_in);
2727 /* Process all insns in this block. Keep track of NEXT so that we
2728 don't process insns emitted while substituting in INSN. */
2729 next = BB_HEAD (block);
2730 regstack = bi->stack_in;
2734 next = NEXT_INSN (insn);
2736 /* Ensure we have not missed a block boundary. */
2739 if (insn == BB_END (block))
2742 /* Don't bother processing unless there is a stack reg
2743 mentioned or if it's a CALL_INSN. */
2744 if (stack_regs_mentioned (insn)
2745 || GET_CODE (insn) == CALL_INSN)
2749 fprintf (file, " insn %d input stack: ",
2751 print_stack (file, ®stack);
2753 control_flow_insn_deleted |= subst_stack_regs (insn, ®stack);
2760 fprintf (file, "Expected live registers [");
2761 for (reg = FIRST_STACK_REG; reg <= LAST_STACK_REG; ++reg)
2762 if (TEST_HARD_REG_BIT (bi->out_reg_set, reg))
2763 fprintf (file, " %d", reg);
2764 fprintf (file, " ]\nOutput stack: ");
2765 print_stack (file, ®stack);
2768 insn = BB_END (block);
2769 if (GET_CODE (insn) == JUMP_INSN)
2770 insn = PREV_INSN (insn);
2772 /* If the function is declared to return a value, but it returns one
2773 in only some cases, some registers might come live here. Emit
2774 necessary moves for them. */
2776 for (reg = FIRST_STACK_REG; reg <= LAST_STACK_REG; ++reg)
2778 if (TEST_HARD_REG_BIT (bi->out_reg_set, reg)
2779 && ! TEST_HARD_REG_BIT (regstack.reg_set, reg))
2785 fprintf (file, "Emitting insn initializing reg %d\n",
2789 set = gen_rtx_SET (VOIDmode, FP_MODE_REG (reg, SFmode),
2791 insn = emit_insn_after (set, insn);
2792 control_flow_insn_deleted |= subst_stack_regs (insn, ®stack);
2796 /* Amongst the insns possibly deleted during the substitution process above,
2797 might have been the only trapping insn in the block. We purge the now
2798 possibly dead EH edges here to avoid an ICE from fixup_abnormal_edges,
2799 called at the end of convert_regs. The order in which we process the
2800 blocks ensures that we never delete an already processed edge.
2802 Note that, at this point, the CFG may have been damaged by the emission
2803 of instructions after an abnormal call, which moves the basic block end
2804 (and is the reason why we call fixup_abnormal_edges later). So we must
2805 be sure that the trapping insn has been deleted before trying to purge
2806 dead edges, otherwise we risk purging valid edges.
2808 ??? We are normally supposed not to delete trapping insns, so we pretend
2809 that the insns deleted above don't actually trap. It would have been
2810 better to detect this earlier and avoid creating the EH edge in the first
2811 place, still, but we don't have enough information at that time. */
2813 if (control_flow_insn_deleted)
2814 purge_dead_edges (block);
2816 /* Something failed if the stack lives don't match. If we had malformed
2817 asms, we zapped the instruction itself, but that didn't produce the
2818 same pattern of register kills as before. */
2819 GO_IF_HARD_REG_EQUAL (regstack.reg_set, bi->out_reg_set, win);
2820 if (!any_malformed_asm)
2823 bi->stack_out = regstack;
2825 /* Compensate the back edges, as those wasn't visited yet. */
2826 for (e = block->succ; e ; e = e->succ_next)
2828 if (e->flags & EDGE_DFS_BACK
2829 || (e->dest == EXIT_BLOCK_PTR))
2831 if (!BLOCK_INFO (e->dest)->done
2832 && e->dest != block)
2834 inserted |= compensate_edge (e, file);
2837 for (e = block->pred; e ; e = e->pred_next)
2839 if (e != beste && !(e->flags & EDGE_DFS_BACK)
2840 && e->src != ENTRY_BLOCK_PTR)
2842 if (!BLOCK_INFO (e->src)->done)
2844 inserted |= compensate_edge (e, file);
2851 /* Convert registers in all blocks reachable from BLOCK. */
2854 convert_regs_2 (FILE *file, basic_block block)
2856 basic_block *stack, *sp;
2859 /* We process the blocks in a top-down manner, in a way such that one block
2860 is only processed after all its predecessors. The number of predecessors
2861 of every block has already been computed. */
2863 stack = xmalloc (sizeof (*stack) * n_basic_blocks);
2875 /* Processing BLOCK is achieved by convert_regs_1, which may purge
2876 some dead EH outgoing edge after the deletion of the trapping
2877 insn inside the block. Since the number of predecessors of
2878 BLOCK's successors was computed based on the initial edge set,
2879 we check the necessity to process some of these successors
2880 before such an edge deletion may happen. However, there is
2881 a pitfall: if BLOCK is the only predecessor of a successor and
2882 the edge between them happens to be deleted, the successor
2883 becomes unreachable and should not be processed. The problem
2884 is that there is no way to preventively detect this case so we
2885 stack the successor in all cases and hand over the task of
2886 fixing up the discrepancy to convert_regs_1. */
2888 for (e = block->succ; e ; e = e->succ_next)
2889 if (! (e->flags & EDGE_DFS_BACK))
2891 BLOCK_INFO (e->dest)->predecessors--;
2892 if (!BLOCK_INFO (e->dest)->predecessors)
2896 inserted |= convert_regs_1 (file, block);
2897 BLOCK_INFO (block)->done = 1;
2899 while (sp != stack);
2904 /* Traverse all basic blocks in a function, converting the register
2905 references in each insn from the "flat" register file that gcc uses,
2906 to the stack-like registers the 387 uses. */
2909 convert_regs (FILE *file)
2915 /* Initialize uninitialized registers on function entry. */
2916 inserted = convert_regs_entry ();
2918 /* Construct the desired stack for function exit. */
2919 convert_regs_exit ();
2920 BLOCK_INFO (EXIT_BLOCK_PTR)->done = 1;
2922 /* ??? Future: process inner loops first, and give them arbitrary
2923 initial stacks which emit_swap_insn can modify. This ought to
2924 prevent double fxch that aften appears at the head of a loop. */
2926 /* Process all blocks reachable from all entry points. */
2927 for (e = ENTRY_BLOCK_PTR->succ; e ; e = e->succ_next)
2928 inserted |= convert_regs_2 (file, e->dest);
2930 /* ??? Process all unreachable blocks. Though there's no excuse
2931 for keeping these even when not optimizing. */
2934 block_info bi = BLOCK_INFO (b);
2937 inserted |= convert_regs_2 (file, b);
2939 clear_aux_for_blocks ();
2941 fixup_abnormal_edges ();
2943 commit_edge_insertions ();
2950 #endif /* STACK_REGS */
2952 #include "gt-reg-stack.h"