1 /* Allocate registers within a basic block, for GNU compiler.
2 Copyright (C) 1987, 1988, 1991, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000 Free Software Foundation, Inc.
5 This file is part of GNU CC.
7 GNU CC is free software; you can redistribute it and/or modify
8 it 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 GNU CC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GNU CC; see the file COPYING. If not, write to
19 the Free Software Foundation, 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
22 /* Allocation of hard register numbers to pseudo registers is done in
23 two passes. In this pass we consider only regs that are born and
24 die once within one basic block. We do this one basic block at a
25 time. Then the next pass allocates the registers that remain.
26 Two passes are used because this pass uses methods that work only
27 on linear code, but that do a better job than the general methods
28 used in global_alloc, and more quickly too.
30 The assignments made are recorded in the vector reg_renumber
31 whose space is allocated here. The rtl code itself is not altered.
33 We assign each instruction in the basic block a number
34 which is its order from the beginning of the block.
35 Then we can represent the lifetime of a pseudo register with
36 a pair of numbers, and check for conflicts easily.
37 We can record the availability of hard registers with a
38 HARD_REG_SET for each instruction. The HARD_REG_SET
39 contains 0 or 1 for each hard reg.
41 To avoid register shuffling, we tie registers together when one
42 dies by being copied into another, or dies in an instruction that
43 does arithmetic to produce another. The tied registers are
44 allocated as one. Registers with different reg class preferences
45 can never be tied unless the class preferred by one is a subclass
46 of the one preferred by the other.
48 Tying is represented with "quantity numbers".
49 A non-tied register is given a new quantity number.
50 Tied registers have the same quantity number.
52 We have provision to exempt registers, even when they are contained
53 within the block, that can be tied to others that are not contained in it.
54 This is so that global_alloc could process them both and tie them then.
55 But this is currently disabled since tying in global_alloc is not
58 /* Pseudos allocated here can be reallocated by global.c if the hard register
59 is used as a spill register. Currently we don't allocate such pseudos
60 here if their preferred class is likely to be used by spills. */
67 #include "hard-reg-set.h"
68 #include "basic-block.h"
71 #include "insn-config.h"
72 #include "insn-attr.h"
77 /* Next quantity number available for allocation. */
81 /* Information we maitain about each quantity. */
84 /* The number of refs to quantity Q. */
88 /* Insn number (counting from head of basic block)
89 where quantity Q was born. -1 if birth has not been recorded. */
93 /* Insn number (counting from head of basic block)
94 where given quantity died. Due to the way tying is done,
95 and the fact that we consider in this pass only regs that die but once,
96 a quantity can die only once. Each quantity's life span
97 is a set of consecutive insns. -1 if death has not been recorded. */
101 /* Number of words needed to hold the data in given quantity.
102 This depends on its machine mode. It is used for these purposes:
103 1. It is used in computing the relative importances of qtys,
104 which determines the order in which we look for regs for them.
105 2. It is used in rules that prevent tying several registers of
106 different sizes in a way that is geometrically impossible
107 (see combine_regs). */
111 /* Number of times a reg tied to given qty lives across a CALL_INSN. */
115 /* The register number of one pseudo register whose reg_qty value is Q.
116 This register should be the head of the chain
117 maintained in reg_next_in_qty. */
121 /* Reg class contained in (smaller than) the preferred classes of all
122 the pseudo regs that are tied in given quantity.
123 This is the preferred class for allocating that quantity. */
125 enum reg_class min_class;
127 /* Register class within which we allocate given qty if we can't get
128 its preferred class. */
130 enum reg_class alternate_class;
132 /* This holds the mode of the registers that are tied to given qty,
133 or VOIDmode if registers with differing modes are tied together. */
135 enum machine_mode mode;
137 /* the hard reg number chosen for given quantity,
138 or -1 if none was found. */
142 /* Nonzero if this quantity has been used in a SUBREG in some
143 way that is illegal. */
149 static struct qty *qty;
151 /* These fields are kept separately to speedup their clearing. */
153 /* We maintain two hard register sets that indicate suggested hard registers
154 for each quantity. The first, phys_copy_sugg, contains hard registers
155 that are tied to the quantity by a simple copy. The second contains all
156 hard registers that are tied to the quantity via an arithmetic operation.
158 The former register set is given priority for allocation. This tends to
159 eliminate copy insns. */
161 /* Element Q is a set of hard registers that are suggested for quantity Q by
164 static HARD_REG_SET *qty_phys_copy_sugg;
166 /* Element Q is a set of hard registers that are suggested for quantity Q by
169 static HARD_REG_SET *qty_phys_sugg;
171 /* Element Q is the number of suggested registers in qty_phys_copy_sugg. */
173 static short *qty_phys_num_copy_sugg;
175 /* Element Q is the number of suggested registers in qty_phys_sugg. */
177 static short *qty_phys_num_sugg;
179 /* If (REG N) has been assigned a quantity number, is a register number
180 of another register assigned the same quantity number, or -1 for the
181 end of the chain. qty->first_reg point to the head of this chain. */
183 static int *reg_next_in_qty;
185 /* reg_qty[N] (where N is a pseudo reg number) is the qty number of that reg
187 of -1 if this register cannot be allocated by local-alloc,
188 or -2 if not known yet.
190 Note that if we see a use or death of pseudo register N with
191 reg_qty[N] == -2, register N must be local to the current block. If
192 it were used in more than one block, we would have reg_qty[N] == -1.
193 This relies on the fact that if reg_basic_block[N] is >= 0, register N
194 will not appear in any other block. We save a considerable number of
195 tests by exploiting this.
197 If N is < FIRST_PSEUDO_REGISTER, reg_qty[N] is undefined and should not
202 /* The offset (in words) of register N within its quantity.
203 This can be nonzero if register N is SImode, and has been tied
204 to a subreg of a DImode register. */
206 static char *reg_offset;
208 /* Vector of substitutions of register numbers,
209 used to map pseudo regs into hardware regs.
210 This is set up as a result of register allocation.
211 Element N is the hard reg assigned to pseudo reg N,
212 or is -1 if no hard reg was assigned.
213 If N is a hard reg number, element N is N. */
217 /* Set of hard registers live at the current point in the scan
218 of the instructions in a basic block. */
220 static HARD_REG_SET regs_live;
222 /* Each set of hard registers indicates registers live at a particular
223 point in the basic block. For N even, regs_live_at[N] says which
224 hard registers are needed *after* insn N/2 (i.e., they may not
225 conflict with the outputs of insn N/2 or the inputs of insn N/2 + 1.
227 If an object is to conflict with the inputs of insn J but not the
228 outputs of insn J + 1, we say it is born at index J*2 - 1. Similarly,
229 if it is to conflict with the outputs of insn J but not the inputs of
230 insn J + 1, it is said to die at index J*2 + 1. */
232 static HARD_REG_SET *regs_live_at;
234 /* Communicate local vars `insn_number' and `insn'
235 from `block_alloc' to `reg_is_set', `wipe_dead_reg', and `alloc_qty'. */
236 static int this_insn_number;
237 static rtx this_insn;
241 /* Set when an attempt should be made to replace a register
242 with the associated src entry. */
246 /* Set when a REG_EQUIV note is found or created. Use to
247 keep track of what memory accesses might be created later,
254 /* Loop depth is used to recognize equivalences which appear
255 to be present within the same loop (or in an inner loop). */
259 /* The list of each instruction which initializes this register. */
264 /* reg_equiv[N] (where N is a pseudo reg number) is the equivalence
265 structure for that register. */
267 static struct equivalence *reg_equiv;
269 /* Nonzero if we recorded an equivalence for a LABEL_REF. */
270 static int recorded_label_ref;
272 static void alloc_qty PARAMS ((int, enum machine_mode, int, int));
273 static void validate_equiv_mem_from_store PARAMS ((rtx, rtx, void *));
274 static int validate_equiv_mem PARAMS ((rtx, rtx, rtx));
275 static int equiv_init_varies_p PARAMS ((rtx));
276 static int equiv_init_movable_p PARAMS ((rtx, int));
277 static int contains_replace_regs PARAMS ((rtx));
278 static int memref_referenced_p PARAMS ((rtx, rtx));
279 static int memref_used_between_p PARAMS ((rtx, rtx, rtx));
280 static void update_equiv_regs PARAMS ((void));
281 static void no_equiv PARAMS ((rtx, rtx, void *));
282 static void block_alloc PARAMS ((int));
283 static int qty_sugg_compare PARAMS ((int, int));
284 static int qty_sugg_compare_1 PARAMS ((const PTR, const PTR));
285 static int qty_compare PARAMS ((int, int));
286 static int qty_compare_1 PARAMS ((const PTR, const PTR));
287 static int combine_regs PARAMS ((rtx, rtx, int, int, rtx, int));
288 static int reg_meets_class_p PARAMS ((int, enum reg_class));
289 static void update_qty_class PARAMS ((int, int));
290 static void reg_is_set PARAMS ((rtx, rtx, void *));
291 static void reg_is_born PARAMS ((rtx, int));
292 static void wipe_dead_reg PARAMS ((rtx, int));
293 static int find_free_reg PARAMS ((enum reg_class, enum machine_mode,
294 int, int, int, int, int));
295 static void mark_life PARAMS ((int, enum machine_mode, int));
296 static void post_mark_life PARAMS ((int, enum machine_mode, int, int, int));
297 static int no_conflict_p PARAMS ((rtx, rtx, rtx));
298 static int requires_inout PARAMS ((const char *));
300 /* Allocate a new quantity (new within current basic block)
301 for register number REGNO which is born at index BIRTH
302 within the block. MODE and SIZE are info on reg REGNO. */
305 alloc_qty (regno, mode, size, birth)
307 enum machine_mode mode;
310 register int qtyno = next_qty++;
312 reg_qty[regno] = qtyno;
313 reg_offset[regno] = 0;
314 reg_next_in_qty[regno] = -1;
316 qty[qtyno].first_reg = regno;
317 qty[qtyno].size = size;
318 qty[qtyno].mode = mode;
319 qty[qtyno].birth = birth;
320 qty[qtyno].n_calls_crossed = REG_N_CALLS_CROSSED (regno);
321 qty[qtyno].min_class = reg_preferred_class (regno);
322 qty[qtyno].alternate_class = reg_alternate_class (regno);
323 qty[qtyno].n_refs = REG_N_REFS (regno);
324 qty[qtyno].changes_mode = REG_CHANGES_MODE (regno);
327 /* Main entry point of this file. */
335 /* We need to keep track of whether or not we recorded a LABEL_REF so
336 that we know if the jump optimizer needs to be rerun. */
337 recorded_label_ref = 0;
339 /* Leaf functions and non-leaf functions have different needs.
340 If defined, let the machine say what kind of ordering we
342 #ifdef ORDER_REGS_FOR_LOCAL_ALLOC
343 ORDER_REGS_FOR_LOCAL_ALLOC;
346 /* Promote REG_EQUAL notes to REG_EQUIV notes and adjust status of affected
348 update_equiv_regs ();
350 /* This sets the maximum number of quantities we can have. Quantity
351 numbers start at zero and we can have one for each pseudo. */
352 max_qty = (max_regno - FIRST_PSEUDO_REGISTER);
354 /* Allocate vectors of temporary data.
355 See the declarations of these variables, above,
356 for what they mean. */
358 qty = (struct qty *) xmalloc (max_qty * sizeof (struct qty));
360 = (HARD_REG_SET *) xmalloc (max_qty * sizeof (HARD_REG_SET));
361 qty_phys_num_copy_sugg = (short *) xmalloc (max_qty * sizeof (short));
362 qty_phys_sugg = (HARD_REG_SET *) xmalloc (max_qty * sizeof (HARD_REG_SET));
363 qty_phys_num_sugg = (short *) xmalloc (max_qty * sizeof (short));
365 reg_qty = (int *) xmalloc (max_regno * sizeof (int));
366 reg_offset = (char *) xmalloc (max_regno * sizeof (char));
367 reg_next_in_qty = (int *) xmalloc (max_regno * sizeof (int));
369 /* Allocate the reg_renumber array. */
370 allocate_reg_info (max_regno, FALSE, TRUE);
372 /* Determine which pseudo-registers can be allocated by local-alloc.
373 In general, these are the registers used only in a single block and
376 We need not be concerned with which block actually uses the register
377 since we will never see it outside that block. */
379 for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
381 if (REG_BASIC_BLOCK (i) >= 0 && REG_N_DEATHS (i) == 1)
387 /* Force loop below to initialize entire quantity array. */
390 /* Allocate each block's local registers, block by block. */
392 for (b = 0; b < n_basic_blocks; b++)
394 /* NEXT_QTY indicates which elements of the `qty_...'
395 vectors might need to be initialized because they were used
396 for the previous block; it is set to the entire array before
397 block 0. Initialize those, with explicit loop if there are few,
398 else with bzero and bcopy. Do not initialize vectors that are
399 explicit set by `alloc_qty'. */
403 for (i = 0; i < next_qty; i++)
405 CLEAR_HARD_REG_SET (qty_phys_copy_sugg[i]);
406 qty_phys_num_copy_sugg[i] = 0;
407 CLEAR_HARD_REG_SET (qty_phys_sugg[i]);
408 qty_phys_num_sugg[i] = 0;
413 #define CLEAR(vector) \
414 memset ((char *) (vector), 0, (sizeof (*(vector))) * next_qty);
416 CLEAR (qty_phys_copy_sugg);
417 CLEAR (qty_phys_num_copy_sugg);
418 CLEAR (qty_phys_sugg);
419 CLEAR (qty_phys_num_sugg);
428 free (qty_phys_copy_sugg);
429 free (qty_phys_num_copy_sugg);
430 free (qty_phys_sugg);
431 free (qty_phys_num_sugg);
435 free (reg_next_in_qty);
437 return recorded_label_ref;
440 /* Used for communication between the following two functions: contains
441 a MEM that we wish to ensure remains unchanged. */
442 static rtx equiv_mem;
444 /* Set nonzero if EQUIV_MEM is modified. */
445 static int equiv_mem_modified;
447 /* If EQUIV_MEM is modified by modifying DEST, indicate that it is modified.
448 Called via note_stores. */
451 validate_equiv_mem_from_store (dest, set, data)
453 rtx set ATTRIBUTE_UNUSED;
454 void *data ATTRIBUTE_UNUSED;
456 if ((GET_CODE (dest) == REG
457 && reg_overlap_mentioned_p (dest, equiv_mem))
458 || (GET_CODE (dest) == MEM
459 && true_dependence (dest, VOIDmode, equiv_mem, rtx_varies_p)))
460 equiv_mem_modified = 1;
463 /* Verify that no store between START and the death of REG invalidates
464 MEMREF. MEMREF is invalidated by modifying a register used in MEMREF,
465 by storing into an overlapping memory location, or with a non-const
468 Return 1 if MEMREF remains valid. */
471 validate_equiv_mem (start, reg, memref)
480 equiv_mem_modified = 0;
482 /* If the memory reference has side effects or is volatile, it isn't a
483 valid equivalence. */
484 if (side_effects_p (memref))
487 for (insn = start; insn && ! equiv_mem_modified; insn = NEXT_INSN (insn))
492 if (find_reg_note (insn, REG_DEAD, reg))
495 if (GET_CODE (insn) == CALL_INSN && ! RTX_UNCHANGING_P (memref)
496 && ! CONST_CALL_P (insn))
499 note_stores (PATTERN (insn), validate_equiv_mem_from_store, NULL);
501 /* If a register mentioned in MEMREF is modified via an
502 auto-increment, we lose the equivalence. Do the same if one
503 dies; although we could extend the life, it doesn't seem worth
506 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
507 if ((REG_NOTE_KIND (note) == REG_INC
508 || REG_NOTE_KIND (note) == REG_DEAD)
509 && GET_CODE (XEXP (note, 0)) == REG
510 && reg_overlap_mentioned_p (XEXP (note, 0), memref))
517 /* Returns zero if X is known to be invariant. */
520 equiv_init_varies_p (x)
523 register RTX_CODE code = GET_CODE (x);
525 register const char *fmt;
530 return ! RTX_UNCHANGING_P (x) || equiv_init_varies_p (XEXP (x, 0));
543 return reg_equiv[REGNO (x)].replace == 0 && rtx_varies_p (x);
546 if (MEM_VOLATILE_P (x))
555 fmt = GET_RTX_FORMAT (code);
556 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
559 if (equiv_init_varies_p (XEXP (x, i)))
562 else if (fmt[i] == 'E')
565 for (j = 0; j < XVECLEN (x, i); j++)
566 if (equiv_init_varies_p (XVECEXP (x, i, j)))
573 /* Returns non-zero if X (used to initialize register REGNO) is movable.
574 X is only movable if the registers it uses have equivalent initializations
575 which appear to be within the same loop (or in an inner loop) and movable
576 or if they are not candidates for local_alloc and don't vary. */
579 equiv_init_movable_p (x, regno)
585 enum rtx_code code = GET_CODE (x);
590 return equiv_init_movable_p (SET_SRC (x), regno);
605 return (reg_equiv[REGNO (x)].loop_depth >= reg_equiv[regno].loop_depth
606 && reg_equiv[REGNO (x)].replace)
607 || (REG_BASIC_BLOCK (REGNO (x)) < 0 && ! rtx_varies_p (x));
609 case UNSPEC_VOLATILE:
613 if (MEM_VOLATILE_P (x))
622 fmt = GET_RTX_FORMAT (code);
623 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
627 if (! equiv_init_movable_p (XEXP (x, i), regno))
631 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
632 if (! equiv_init_movable_p (XVECEXP (x, i, j), regno))
640 /* TRUE if X uses any registers for which reg_equiv[REGNO].replace is true. */
643 contains_replace_regs (x)
648 enum rtx_code code = GET_CODE (x);
664 return reg_equiv[REGNO (x)].replace;
670 fmt = GET_RTX_FORMAT (code);
671 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
675 if (contains_replace_regs (XEXP (x, i)))
679 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
680 if (contains_replace_regs (XVECEXP (x, i, j)))
688 /* TRUE if X references a memory location that would be affected by a store
692 memref_referenced_p (memref, x)
698 enum rtx_code code = GET_CODE (x);
714 return (reg_equiv[REGNO (x)].replacement
715 && memref_referenced_p (memref,
716 reg_equiv[REGNO (x)].replacement));
719 if (true_dependence (memref, VOIDmode, x, rtx_varies_p))
724 /* If we are setting a MEM, it doesn't count (its address does), but any
725 other SET_DEST that has a MEM in it is referencing the MEM. */
726 if (GET_CODE (SET_DEST (x)) == MEM)
728 if (memref_referenced_p (memref, XEXP (SET_DEST (x), 0)))
731 else if (memref_referenced_p (memref, SET_DEST (x)))
734 return memref_referenced_p (memref, SET_SRC (x));
740 fmt = GET_RTX_FORMAT (code);
741 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
745 if (memref_referenced_p (memref, XEXP (x, i)))
749 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
750 if (memref_referenced_p (memref, XVECEXP (x, i, j)))
758 /* TRUE if some insn in the range (START, END] references a memory location
759 that would be affected by a store to MEMREF. */
762 memref_used_between_p (memref, start, end)
769 for (insn = NEXT_INSN (start); insn != NEXT_INSN (end);
770 insn = NEXT_INSN (insn))
771 if (INSN_P (insn) && memref_referenced_p (memref, PATTERN (insn)))
777 /* Return nonzero if the rtx X is invariant over the current function. */
779 function_invariant_p (x)
784 if (x == frame_pointer_rtx || x == arg_pointer_rtx)
786 if (GET_CODE (x) == PLUS
787 && (XEXP (x, 0) == frame_pointer_rtx || XEXP (x, 0) == arg_pointer_rtx)
788 && CONSTANT_P (XEXP (x, 1)))
793 /* Find registers that are equivalent to a single value throughout the
794 compilation (either because they can be referenced in memory or are set once
795 from a single constant). Lower their priority for a register.
797 If such a register is only referenced once, try substituting its value
798 into the using insn. If it succeeds, we can eliminate the register
808 reg_equiv = (struct equivalence *) xcalloc (max_regno, sizeof *reg_equiv);
810 init_alias_analysis ();
812 /* Scan the insns and find which registers have equivalences. Do this
813 in a separate scan of the insns because (due to -fcse-follow-jumps)
814 a register can be set below its use. */
816 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
823 if (GET_CODE (insn) == NOTE)
825 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)
827 else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END)
838 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
839 if (REG_NOTE_KIND (note) == REG_INC)
840 no_equiv (XEXP (note, 0), note, NULL);
842 set = single_set (insn);
844 /* If this insn contains more (or less) than a single SET,
845 only mark all destinations as having no known equivalence. */
848 note_stores (PATTERN (insn), no_equiv, NULL);
851 else if (GET_CODE (PATTERN (insn)) == PARALLEL)
855 for (i = XVECLEN (PATTERN (insn), 0) - 1; i >= 0; i--)
857 rtx part = XVECEXP (PATTERN (insn), 0, i);
859 note_stores (part, no_equiv, NULL);
863 dest = SET_DEST (set);
866 /* If this sets a MEM to the contents of a REG that is only used
867 in a single basic block, see if the register is always equivalent
868 to that memory location and if moving the store from INSN to the
869 insn that set REG is safe. If so, put a REG_EQUIV note on the
872 Don't add a REG_EQUIV note if the insn already has one. The existing
873 REG_EQUIV is likely more useful than the one we are adding.
875 If one of the regs in the address has reg_equiv[REGNO].replace set,
876 then we can't add this REG_EQUIV note. The reg_equiv[REGNO].replace
877 optimization may move the set of this register immediately before
878 insn, which puts it after reg_equiv[REGNO].init_insns, and hence
879 the mention in the REG_EQUIV note would be to an uninitialized
881 /* ????? This test isn't good enough; we might see a MEM with a use of
882 a pseudo register before we see its setting insn that will cause
883 reg_equiv[].replace for that pseudo to be set.
884 Equivalences to MEMs should be made in another pass, after the
885 reg_equiv[].replace information has been gathered. */
887 if (GET_CODE (dest) == MEM && GET_CODE (src) == REG
888 && (regno = REGNO (src)) >= FIRST_PSEUDO_REGISTER
889 && REG_BASIC_BLOCK (regno) >= 0
890 && REG_N_SETS (regno) == 1
891 && reg_equiv[regno].init_insns != 0
892 && reg_equiv[regno].init_insns != const0_rtx
893 && ! find_reg_note (XEXP (reg_equiv[regno].init_insns, 0),
895 && ! contains_replace_regs (XEXP (dest, 0)))
897 rtx init_insn = XEXP (reg_equiv[regno].init_insns, 0);
898 if (validate_equiv_mem (init_insn, src, dest)
899 && ! memref_used_between_p (dest, init_insn, insn))
900 REG_NOTES (init_insn)
901 = gen_rtx_EXPR_LIST (REG_EQUIV, dest, REG_NOTES (init_insn));
904 /* We only handle the case of a pseudo register being set
905 once, or always to the same value. */
906 /* ??? The mn10200 port breaks if we add equivalences for
907 values that need an ADDRESS_REGS register and set them equivalent
908 to a MEM of a pseudo. The actual problem is in the over-conservative
909 handling of INPADDR_ADDRESS / INPUT_ADDRESS / INPUT triples in
910 calculate_needs, but we traditionally work around this problem
911 here by rejecting equivalences when the destination is in a register
912 that's likely spilled. This is fragile, of course, since the
913 preferred class of a pseudo depends on all instructions that set
916 if (GET_CODE (dest) != REG
917 || (regno = REGNO (dest)) < FIRST_PSEUDO_REGISTER
918 || reg_equiv[regno].init_insns == const0_rtx
919 || (CLASS_LIKELY_SPILLED_P (reg_preferred_class (regno))
920 && GET_CODE (src) == MEM))
922 /* This might be seting a SUBREG of a pseudo, a pseudo that is
923 also set somewhere else to a constant. */
924 note_stores (set, no_equiv, NULL);
928 note = find_reg_note (insn, REG_EQUAL, NULL_RTX);
930 /* cse sometimes generates function invariants, but doesn't put a
931 REG_EQUAL note on the insn. Since this note would be redundant,
932 there's no point creating it earlier than here. */
933 if (! note && ! rtx_varies_p (src))
935 = note = gen_rtx_EXPR_LIST (REG_EQUAL, src, REG_NOTES (insn));
937 /* Don't bother considering a REG_EQUAL note containing an EXPR_LIST
938 since it represents a function call */
939 if (note && GET_CODE (XEXP (note, 0)) == EXPR_LIST)
942 if (REG_N_SETS (regno) != 1
944 || rtx_varies_p (XEXP (note, 0))
945 || (reg_equiv[regno].replacement
946 && ! rtx_equal_p (XEXP (note, 0),
947 reg_equiv[regno].replacement))))
949 no_equiv (dest, set, NULL);
952 /* Record this insn as initializing this register. */
953 reg_equiv[regno].init_insns
954 = gen_rtx_INSN_LIST (VOIDmode, insn, reg_equiv[regno].init_insns);
956 /* If this register is known to be equal to a constant, record that
957 it is always equivalent to the constant. */
958 if (note && ! rtx_varies_p (XEXP (note, 0)))
959 PUT_MODE (note, (enum machine_mode) REG_EQUIV);
961 /* If this insn introduces a "constant" register, decrease the priority
962 of that register. Record this insn if the register is only used once
963 more and the equivalence value is the same as our source.
965 The latter condition is checked for two reasons: First, it is an
966 indication that it may be more efficient to actually emit the insn
967 as written (if no registers are available, reload will substitute
968 the equivalence). Secondly, it avoids problems with any registers
969 dying in this insn whose death notes would be missed.
971 If we don't have a REG_EQUIV note, see if this insn is loading
972 a register used only in one basic block from a MEM. If so, and the
973 MEM remains unchanged for the life of the register, add a REG_EQUIV
976 note = find_reg_note (insn, REG_EQUIV, NULL_RTX);
978 if (note == 0 && REG_BASIC_BLOCK (regno) >= 0
979 && GET_CODE (SET_SRC (set)) == MEM
980 && validate_equiv_mem (insn, dest, SET_SRC (set)))
981 REG_NOTES (insn) = note = gen_rtx_EXPR_LIST (REG_EQUIV, SET_SRC (set),
986 int regno = REGNO (dest);
988 /* Record whether or not we created a REG_EQUIV note for a LABEL_REF.
989 We might end up substituting the LABEL_REF for uses of the
990 pseudo here or later. That kind of transformation may turn an
991 indirect jump into a direct jump, in which case we must rerun the
992 jump optimizer to ensure that the JUMP_LABEL fields are valid. */
993 if (GET_CODE (XEXP (note, 0)) == LABEL_REF
994 || (GET_CODE (XEXP (note, 0)) == CONST
995 && GET_CODE (XEXP (XEXP (note, 0), 0)) == PLUS
996 && (GET_CODE (XEXP (XEXP (XEXP (note, 0), 0), 0))
998 recorded_label_ref = 1;
1000 reg_equiv[regno].replacement = XEXP (note, 0);
1001 reg_equiv[regno].src = src;
1002 reg_equiv[regno].loop_depth = loop_depth;
1004 /* Don't mess with things live during setjmp. */
1005 if (REG_LIVE_LENGTH (regno) >= 0)
1007 /* Note that the statement below does not affect the priority
1009 REG_LIVE_LENGTH (regno) *= 2;
1012 /* If the register is referenced exactly twice, meaning it is
1013 set once and used once, indicate that the reference may be
1014 replaced by the equivalence we computed above. Do this
1015 even if the register is only used in one block so that
1016 dependencies can be handled where the last register is
1017 used in a different block (i.e. HIGH / LO_SUM sequences)
1018 and to reduce the number of registers alive across calls.
1020 It would be nice to use "loop_depth * 2" in the compare
1021 below. Unfortunately, LOOP_DEPTH need not be constant within
1022 a basic block so this would be too complicated.
1024 This case normally occurs when a parameter is read from
1025 memory and then used exactly once, not in a loop. */
1027 if (REG_N_REFS (regno) == 2
1028 && (rtx_equal_p (XEXP (note, 0), src)
1029 || ! equiv_init_varies_p (src))
1030 && GET_CODE (insn) == INSN
1031 && equiv_init_movable_p (PATTERN (insn), regno))
1032 reg_equiv[regno].replace = 1;
1037 /* Now scan all regs killed in an insn to see if any of them are
1038 registers only used that once. If so, see if we can replace the
1039 reference with the equivalent from. If we can, delete the
1040 initializing reference and this register will go away. If we
1041 can't replace the reference, and the initialzing reference is
1042 within the same loop (or in an inner loop), then move the register
1043 initialization just before the use, so that they are in the same
1046 Skip this optimization if loop_depth isn't initially zero since
1047 that indicates a mismatch between loop begin and loop end notes
1048 (i.e. gcc.dg/noncompile/920721-2.c). */
1049 block = n_basic_blocks - 1;
1050 for (insn = (loop_depth == 0) ? get_last_insn () : NULL_RTX;
1051 insn; insn = PREV_INSN (insn))
1055 if (! INSN_P (insn))
1057 if (GET_CODE (insn) == NOTE)
1059 if (NOTE_INSN_BASIC_BLOCK_P (insn))
1060 block = NOTE_BASIC_BLOCK (insn)->index - 1;
1061 else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)
1067 else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END)
1074 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
1076 if (REG_NOTE_KIND (link) == REG_DEAD
1077 /* Make sure this insn still refers to the register. */
1078 && reg_mentioned_p (XEXP (link, 0), PATTERN (insn)))
1080 int regno = REGNO (XEXP (link, 0));
1083 if (! reg_equiv[regno].replace
1084 || reg_equiv[regno].loop_depth < loop_depth)
1087 /* reg_equiv[REGNO].replace gets set only when
1088 REG_N_REFS[REGNO] is 2, i.e. the register is set
1089 once and used once. (If it were only set, but not used,
1090 flow would have deleted the setting insns.) Hence
1091 there can only be one insn in reg_equiv[REGNO].init_insns. */
1092 if (reg_equiv[regno].init_insns == NULL_RTX
1093 || XEXP (reg_equiv[regno].init_insns, 1) != NULL_RTX)
1095 equiv_insn = XEXP (reg_equiv[regno].init_insns, 0);
1097 if (asm_noperands (PATTERN (equiv_insn)) < 0
1098 && validate_replace_rtx (regno_reg_rtx[regno],
1099 reg_equiv[regno].src, insn))
1105 /* Find the last note. */
1106 for (last_link = link; XEXP (last_link, 1);
1107 last_link = XEXP (last_link, 1))
1110 /* Append the REG_DEAD notes from equiv_insn. */
1111 equiv_link = REG_NOTES (equiv_insn);
1115 equiv_link = XEXP (equiv_link, 1);
1116 if (REG_NOTE_KIND (note) == REG_DEAD)
1118 remove_note (equiv_insn, note);
1119 XEXP (last_link, 1) = note;
1120 XEXP (note, 1) = NULL_RTX;
1125 remove_death (regno, insn);
1126 REG_N_REFS (regno) = 0;
1127 PUT_CODE (equiv_insn, NOTE);
1128 NOTE_LINE_NUMBER (equiv_insn) = NOTE_INSN_DELETED;
1129 NOTE_SOURCE_FILE (equiv_insn) = 0;
1131 reg_equiv[regno].init_insns =
1132 XEXP (reg_equiv[regno].init_insns, 1);
1134 /* Move the initialization of the register to just before
1135 INSN. Update the flow information. */
1136 else if (PREV_INSN (insn) != equiv_insn)
1141 new_insn = emit_insn_before (copy_rtx (PATTERN (equiv_insn)),
1143 REG_NOTES (PREV_INSN (insn)) = REG_NOTES (equiv_insn);
1144 REG_NOTES (equiv_insn) = 0;
1146 PUT_CODE (equiv_insn, NOTE);
1147 NOTE_LINE_NUMBER (equiv_insn) = NOTE_INSN_DELETED;
1148 NOTE_SOURCE_FILE (equiv_insn) = 0;
1150 XEXP (reg_equiv[regno].init_insns, 0) = new_insn;
1152 REG_BASIC_BLOCK (regno) = block >= 0 ? block : 0;
1153 REG_N_CALLS_CROSSED (regno) = 0;
1154 REG_LIVE_LENGTH (regno) = 2;
1156 if (block >= 0 && insn == BLOCK_HEAD (block))
1157 BLOCK_HEAD (block) = PREV_INSN (insn);
1159 for (l = 0; l < n_basic_blocks; l++)
1161 CLEAR_REGNO_REG_SET (
1162 BASIC_BLOCK (l)->global_live_at_start,
1164 CLEAR_REGNO_REG_SET (
1165 BASIC_BLOCK (l)->global_live_at_end,
1174 end_alias_analysis ();
1178 /* Mark REG as having no known equivalence.
1179 Some instructions might have been proceessed before and furnished
1180 with REG_EQUIV notes for this register; these notes will have to be
1182 STORE is the piece of RTL that does the non-constant / conflicting
1183 assignment - a SET, CLOBBER or REG_INC note. It is currently not used,
1184 but needs to be there because this function is called from note_stores. */
1186 no_equiv (reg, store, data)
1187 rtx reg, store ATTRIBUTE_UNUSED;
1188 void *data ATTRIBUTE_UNUSED;
1193 if (GET_CODE (reg) != REG)
1195 regno = REGNO (reg);
1196 list = reg_equiv[regno].init_insns;
1197 if (list == const0_rtx)
1199 for (; list; list = XEXP (list, 1))
1201 rtx insn = XEXP (list, 0);
1202 remove_note (insn, find_reg_note (insn, REG_EQUIV, NULL_RTX));
1204 reg_equiv[regno].init_insns = const0_rtx;
1205 reg_equiv[regno].replacement = NULL_RTX;
1208 /* Allocate hard regs to the pseudo regs used only within block number B.
1209 Only the pseudos that die but once can be handled. */
1218 int insn_number = 0;
1220 int max_uid = get_max_uid ();
1222 int no_conflict_combined_regno = -1;
1224 /* Count the instructions in the basic block. */
1226 insn = BLOCK_END (b);
1229 if (GET_CODE (insn) != NOTE)
1230 if (++insn_count > max_uid)
1232 if (insn == BLOCK_HEAD (b))
1234 insn = PREV_INSN (insn);
1237 /* +2 to leave room for a post_mark_life at the last insn and for
1238 the birth of a CLOBBER in the first insn. */
1239 regs_live_at = (HARD_REG_SET *) xcalloc ((2 * insn_count + 2),
1240 sizeof (HARD_REG_SET));
1242 /* Initialize table of hardware registers currently live. */
1244 REG_SET_TO_HARD_REG_SET (regs_live, BASIC_BLOCK (b)->global_live_at_start);
1246 /* This loop scans the instructions of the basic block
1247 and assigns quantities to registers.
1248 It computes which registers to tie. */
1250 insn = BLOCK_HEAD (b);
1253 if (GET_CODE (insn) != NOTE)
1258 register rtx link, set;
1259 register int win = 0;
1260 register rtx r0, r1 = NULL_RTX;
1261 int combined_regno = -1;
1264 this_insn_number = insn_number;
1267 extract_insn (insn);
1268 which_alternative = -1;
1270 /* Is this insn suitable for tying two registers?
1271 If so, try doing that.
1272 Suitable insns are those with at least two operands and where
1273 operand 0 is an output that is a register that is not
1276 We can tie operand 0 with some operand that dies in this insn.
1277 First look for operands that are required to be in the same
1278 register as operand 0. If we find such, only try tying that
1279 operand or one that can be put into that operand if the
1280 operation is commutative. If we don't find an operand
1281 that is required to be in the same register as operand 0,
1282 we can tie with any operand.
1284 Subregs in place of regs are also ok.
1286 If tying is done, WIN is set nonzero. */
1289 && recog_data.n_operands > 1
1290 && recog_data.constraints[0][0] == '='
1291 && recog_data.constraints[0][1] != '&')
1293 /* If non-negative, is an operand that must match operand 0. */
1294 int must_match_0 = -1;
1295 /* Counts number of alternatives that require a match with
1297 int n_matching_alts = 0;
1299 for (i = 1; i < recog_data.n_operands; i++)
1301 const char *p = recog_data.constraints[i];
1302 int this_match = (requires_inout (p));
1304 n_matching_alts += this_match;
1305 if (this_match == recog_data.n_alternatives)
1309 r0 = recog_data.operand[0];
1310 for (i = 1; i < recog_data.n_operands; i++)
1312 /* Skip this operand if we found an operand that
1313 must match operand 0 and this operand isn't it
1314 and can't be made to be it by commutativity. */
1316 if (must_match_0 >= 0 && i != must_match_0
1317 && ! (i == must_match_0 + 1
1318 && recog_data.constraints[i-1][0] == '%')
1319 && ! (i == must_match_0 - 1
1320 && recog_data.constraints[i][0] == '%'))
1323 /* Likewise if each alternative has some operand that
1324 must match operand zero. In that case, skip any
1325 operand that doesn't list operand 0 since we know that
1326 the operand always conflicts with operand 0. We
1327 ignore commutatity in this case to keep things simple. */
1328 if (n_matching_alts == recog_data.n_alternatives
1329 && 0 == requires_inout (recog_data.constraints[i]))
1332 r1 = recog_data.operand[i];
1334 /* If the operand is an address, find a register in it.
1335 There may be more than one register, but we only try one
1337 if (recog_data.constraints[i][0] == 'p')
1338 while (GET_CODE (r1) == PLUS || GET_CODE (r1) == MULT)
1341 if (GET_CODE (r0) == REG || GET_CODE (r0) == SUBREG)
1343 /* We have two priorities for hard register preferences.
1344 If we have a move insn or an insn whose first input
1345 can only be in the same register as the output, give
1346 priority to an equivalence found from that insn. */
1348 = (r1 == recog_data.operand[i] && must_match_0 >= 0);
1350 if (GET_CODE (r1) == REG || GET_CODE (r1) == SUBREG)
1351 win = combine_regs (r1, r0, may_save_copy,
1352 insn_number, insn, 0);
1359 /* Recognize an insn sequence with an ultimate result
1360 which can safely overlap one of the inputs.
1361 The sequence begins with a CLOBBER of its result,
1362 and ends with an insn that copies the result to itself
1363 and has a REG_EQUAL note for an equivalent formula.
1364 That note indicates what the inputs are.
1365 The result and the input can overlap if each insn in
1366 the sequence either doesn't mention the input
1367 or has a REG_NO_CONFLICT note to inhibit the conflict.
1369 We do the combining test at the CLOBBER so that the
1370 destination register won't have had a quantity number
1371 assigned, since that would prevent combining. */
1374 && GET_CODE (PATTERN (insn)) == CLOBBER
1375 && (r0 = XEXP (PATTERN (insn), 0),
1376 GET_CODE (r0) == REG)
1377 && (link = find_reg_note (insn, REG_LIBCALL, NULL_RTX)) != 0
1378 && XEXP (link, 0) != 0
1379 && GET_CODE (XEXP (link, 0)) == INSN
1380 && (set = single_set (XEXP (link, 0))) != 0
1381 && SET_DEST (set) == r0 && SET_SRC (set) == r0
1382 && (note = find_reg_note (XEXP (link, 0), REG_EQUAL,
1385 if (r1 = XEXP (note, 0), GET_CODE (r1) == REG
1386 /* Check that we have such a sequence. */
1387 && no_conflict_p (insn, r0, r1))
1388 win = combine_regs (r1, r0, 1, insn_number, insn, 1);
1389 else if (GET_RTX_FORMAT (GET_CODE (XEXP (note, 0)))[0] == 'e'
1390 && (r1 = XEXP (XEXP (note, 0), 0),
1391 GET_CODE (r1) == REG || GET_CODE (r1) == SUBREG)
1392 && no_conflict_p (insn, r0, r1))
1393 win = combine_regs (r1, r0, 0, insn_number, insn, 1);
1395 /* Here we care if the operation to be computed is
1397 else if ((GET_CODE (XEXP (note, 0)) == EQ
1398 || GET_CODE (XEXP (note, 0)) == NE
1399 || GET_RTX_CLASS (GET_CODE (XEXP (note, 0))) == 'c')
1400 && (r1 = XEXP (XEXP (note, 0), 1),
1401 (GET_CODE (r1) == REG || GET_CODE (r1) == SUBREG))
1402 && no_conflict_p (insn, r0, r1))
1403 win = combine_regs (r1, r0, 0, insn_number, insn, 1);
1405 /* If we did combine something, show the register number
1406 in question so that we know to ignore its death. */
1408 no_conflict_combined_regno = REGNO (r1);
1411 /* If registers were just tied, set COMBINED_REGNO
1412 to the number of the register used in this insn
1413 that was tied to the register set in this insn.
1414 This register's qty should not be "killed". */
1418 while (GET_CODE (r1) == SUBREG)
1419 r1 = SUBREG_REG (r1);
1420 combined_regno = REGNO (r1);
1423 /* Mark the death of everything that dies in this instruction,
1424 except for anything that was just combined. */
1426 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
1427 if (REG_NOTE_KIND (link) == REG_DEAD
1428 && GET_CODE (XEXP (link, 0)) == REG
1429 && combined_regno != (int) REGNO (XEXP (link, 0))
1430 && (no_conflict_combined_regno != (int) REGNO (XEXP (link, 0))
1431 || ! find_reg_note (insn, REG_NO_CONFLICT,
1433 wipe_dead_reg (XEXP (link, 0), 0);
1435 /* Allocate qty numbers for all registers local to this block
1436 that are born (set) in this instruction.
1437 A pseudo that already has a qty is not changed. */
1439 note_stores (PATTERN (insn), reg_is_set, NULL);
1441 /* If anything is set in this insn and then unused, mark it as dying
1442 after this insn, so it will conflict with our outputs. This
1443 can't match with something that combined, and it doesn't matter
1444 if it did. Do this after the calls to reg_is_set since these
1445 die after, not during, the current insn. */
1447 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
1448 if (REG_NOTE_KIND (link) == REG_UNUSED
1449 && GET_CODE (XEXP (link, 0)) == REG)
1450 wipe_dead_reg (XEXP (link, 0), 1);
1452 /* If this is an insn that has a REG_RETVAL note pointing at a
1453 CLOBBER insn, we have reached the end of a REG_NO_CONFLICT
1454 block, so clear any register number that combined within it. */
1455 if ((note = find_reg_note (insn, REG_RETVAL, NULL_RTX)) != 0
1456 && GET_CODE (XEXP (note, 0)) == INSN
1457 && GET_CODE (PATTERN (XEXP (note, 0))) == CLOBBER)
1458 no_conflict_combined_regno = -1;
1461 /* Set the registers live after INSN_NUMBER. Note that we never
1462 record the registers live before the block's first insn, since no
1463 pseudos we care about are live before that insn. */
1465 IOR_HARD_REG_SET (regs_live_at[2 * insn_number], regs_live);
1466 IOR_HARD_REG_SET (regs_live_at[2 * insn_number + 1], regs_live);
1468 if (insn == BLOCK_END (b))
1471 insn = NEXT_INSN (insn);
1474 /* Now every register that is local to this basic block
1475 should have been given a quantity, or else -1 meaning ignore it.
1476 Every quantity should have a known birth and death.
1478 Order the qtys so we assign them registers in order of the
1479 number of suggested registers they need so we allocate those with
1480 the most restrictive needs first. */
1482 qty_order = (int *) xmalloc (next_qty * sizeof (int));
1483 for (i = 0; i < next_qty; i++)
1486 #define EXCHANGE(I1, I2) \
1487 { i = qty_order[I1]; qty_order[I1] = qty_order[I2]; qty_order[I2] = i; }
1492 /* Make qty_order[2] be the one to allocate last. */
1493 if (qty_sugg_compare (0, 1) > 0)
1495 if (qty_sugg_compare (1, 2) > 0)
1498 /* ... Fall through ... */
1500 /* Put the best one to allocate in qty_order[0]. */
1501 if (qty_sugg_compare (0, 1) > 0)
1504 /* ... Fall through ... */
1508 /* Nothing to do here. */
1512 qsort (qty_order, next_qty, sizeof (int), qty_sugg_compare_1);
1515 /* Try to put each quantity in a suggested physical register, if it has one.
1516 This may cause registers to be allocated that otherwise wouldn't be, but
1517 this seems acceptable in local allocation (unlike global allocation). */
1518 for (i = 0; i < next_qty; i++)
1521 if (qty_phys_num_sugg[q] != 0 || qty_phys_num_copy_sugg[q] != 0)
1522 qty[q].phys_reg = find_free_reg (qty[q].min_class, qty[q].mode, q,
1523 0, 1, qty[q].birth, qty[q].death);
1525 qty[q].phys_reg = -1;
1528 /* Order the qtys so we assign them registers in order of
1529 decreasing length of life. Normally call qsort, but if we
1530 have only a very small number of quantities, sort them ourselves. */
1532 for (i = 0; i < next_qty; i++)
1535 #define EXCHANGE(I1, I2) \
1536 { i = qty_order[I1]; qty_order[I1] = qty_order[I2]; qty_order[I2] = i; }
1541 /* Make qty_order[2] be the one to allocate last. */
1542 if (qty_compare (0, 1) > 0)
1544 if (qty_compare (1, 2) > 0)
1547 /* ... Fall through ... */
1549 /* Put the best one to allocate in qty_order[0]. */
1550 if (qty_compare (0, 1) > 0)
1553 /* ... Fall through ... */
1557 /* Nothing to do here. */
1561 qsort (qty_order, next_qty, sizeof (int), qty_compare_1);
1564 /* Now for each qty that is not a hardware register,
1565 look for a hardware register to put it in.
1566 First try the register class that is cheapest for this qty,
1567 if there is more than one class. */
1569 for (i = 0; i < next_qty; i++)
1572 if (qty[q].phys_reg < 0)
1574 #ifdef INSN_SCHEDULING
1575 /* These values represent the adjusted lifetime of a qty so
1576 that it conflicts with qtys which appear near the start/end
1577 of this qty's lifetime.
1579 The purpose behind extending the lifetime of this qty is to
1580 discourage the register allocator from creating false
1583 The adjustment value is choosen to indicate that this qty
1584 conflicts with all the qtys in the instructions immediately
1585 before and after the lifetime of this qty.
1587 Experiments have shown that higher values tend to hurt
1588 overall code performance.
1590 If allocation using the extended lifetime fails we will try
1591 again with the qty's unadjusted lifetime. */
1592 int fake_birth = MAX (0, qty[q].birth - 2 + qty[q].birth % 2);
1593 int fake_death = MIN (insn_number * 2 + 1,
1594 qty[q].death + 2 - qty[q].death % 2);
1597 if (N_REG_CLASSES > 1)
1599 #ifdef INSN_SCHEDULING
1600 /* We try to avoid using hard registers allocated to qtys which
1601 are born immediately after this qty or die immediately before
1604 This optimization is only appropriate when we will run
1605 a scheduling pass after reload and we are not optimizing
1607 if (flag_schedule_insns_after_reload
1609 && !SMALL_REGISTER_CLASSES)
1611 qty[q].phys_reg = find_free_reg (qty[q].min_class,
1612 qty[q].mode, q, 0, 0,
1613 fake_birth, fake_death);
1614 if (qty[q].phys_reg >= 0)
1618 qty[q].phys_reg = find_free_reg (qty[q].min_class,
1619 qty[q].mode, q, 0, 0,
1620 qty[q].birth, qty[q].death);
1621 if (qty[q].phys_reg >= 0)
1625 #ifdef INSN_SCHEDULING
1626 /* Similarly, avoid false dependencies. */
1627 if (flag_schedule_insns_after_reload
1629 && !SMALL_REGISTER_CLASSES
1630 && qty[q].alternate_class != NO_REGS)
1631 qty[q].phys_reg = find_free_reg (qty[q].alternate_class,
1632 qty[q].mode, q, 0, 0,
1633 fake_birth, fake_death);
1635 if (qty[q].alternate_class != NO_REGS)
1636 qty[q].phys_reg = find_free_reg (qty[q].alternate_class,
1637 qty[q].mode, q, 0, 0,
1638 qty[q].birth, qty[q].death);
1642 /* Now propagate the register assignments
1643 to the pseudo regs belonging to the qtys. */
1645 for (q = 0; q < next_qty; q++)
1646 if (qty[q].phys_reg >= 0)
1648 for (i = qty[q].first_reg; i >= 0; i = reg_next_in_qty[i])
1649 reg_renumber[i] = qty[q].phys_reg + reg_offset[i];
1653 free (regs_live_at);
1657 /* Compare two quantities' priority for getting real registers.
1658 We give shorter-lived quantities higher priority.
1659 Quantities with more references are also preferred, as are quantities that
1660 require multiple registers. This is the identical prioritization as
1661 done by global-alloc.
1663 We used to give preference to registers with *longer* lives, but using
1664 the same algorithm in both local- and global-alloc can speed up execution
1665 of some programs by as much as a factor of three! */
1667 /* Note that the quotient will never be bigger than
1668 the value of floor_log2 times the maximum number of
1669 times a register can occur in one insn (surely less than 100).
1670 Multiplying this by 10000 can't overflow.
1671 QTY_CMP_PRI is also used by qty_sugg_compare. */
1673 #define QTY_CMP_PRI(q) \
1674 ((int) (((double) (floor_log2 (qty[q].n_refs) * qty[q].n_refs * qty[q].size) \
1675 / (qty[q].death - qty[q].birth)) * 10000))
1678 qty_compare (q1, q2)
1681 return QTY_CMP_PRI (q2) - QTY_CMP_PRI (q1);
1685 qty_compare_1 (q1p, q2p)
1689 register int q1 = *(const int *) q1p, q2 = *(const int *) q2p;
1690 register int tem = QTY_CMP_PRI (q2) - QTY_CMP_PRI (q1);
1695 /* If qtys are equally good, sort by qty number,
1696 so that the results of qsort leave nothing to chance. */
1700 /* Compare two quantities' priority for getting real registers. This version
1701 is called for quantities that have suggested hard registers. First priority
1702 goes to quantities that have copy preferences, then to those that have
1703 normal preferences. Within those groups, quantities with the lower
1704 number of preferences have the highest priority. Of those, we use the same
1705 algorithm as above. */
1707 #define QTY_CMP_SUGG(q) \
1708 (qty_phys_num_copy_sugg[q] \
1709 ? qty_phys_num_copy_sugg[q] \
1710 : qty_phys_num_sugg[q] * FIRST_PSEUDO_REGISTER)
1713 qty_sugg_compare (q1, q2)
1716 register int tem = QTY_CMP_SUGG (q1) - QTY_CMP_SUGG (q2);
1721 return QTY_CMP_PRI (q2) - QTY_CMP_PRI (q1);
1725 qty_sugg_compare_1 (q1p, q2p)
1729 register int q1 = *(const int *) q1p, q2 = *(const int *) q2p;
1730 register int tem = QTY_CMP_SUGG (q1) - QTY_CMP_SUGG (q2);
1735 tem = QTY_CMP_PRI (q2) - QTY_CMP_PRI (q1);
1739 /* If qtys are equally good, sort by qty number,
1740 so that the results of qsort leave nothing to chance. */
1747 /* Attempt to combine the two registers (rtx's) USEDREG and SETREG.
1748 Returns 1 if have done so, or 0 if cannot.
1750 Combining registers means marking them as having the same quantity
1751 and adjusting the offsets within the quantity if either of
1754 We don't actually combine a hard reg with a pseudo; instead
1755 we just record the hard reg as the suggestion for the pseudo's quantity.
1756 If we really combined them, we could lose if the pseudo lives
1757 across an insn that clobbers the hard reg (eg, movstr).
1759 ALREADY_DEAD is non-zero if USEDREG is known to be dead even though
1760 there is no REG_DEAD note on INSN. This occurs during the processing
1761 of REG_NO_CONFLICT blocks.
1763 MAY_SAVE_COPYCOPY is non-zero if this insn is simply copying USEDREG to
1764 SETREG or if the input and output must share a register.
1765 In that case, we record a hard reg suggestion in QTY_PHYS_COPY_SUGG.
1767 There are elaborate checks for the validity of combining. */
1770 combine_regs (usedreg, setreg, may_save_copy, insn_number, insn, already_dead)
1771 rtx usedreg, setreg;
1777 register int ureg, sreg;
1778 register int offset = 0;
1782 /* Determine the numbers and sizes of registers being used. If a subreg
1783 is present that does not change the entire register, don't consider
1784 this a copy insn. */
1786 while (GET_CODE (usedreg) == SUBREG)
1788 if (GET_MODE_SIZE (GET_MODE (SUBREG_REG (usedreg))) > UNITS_PER_WORD)
1790 offset += SUBREG_WORD (usedreg);
1791 usedreg = SUBREG_REG (usedreg);
1793 if (GET_CODE (usedreg) != REG)
1795 ureg = REGNO (usedreg);
1796 usize = REG_SIZE (usedreg);
1798 while (GET_CODE (setreg) == SUBREG)
1800 if (GET_MODE_SIZE (GET_MODE (SUBREG_REG (setreg))) > UNITS_PER_WORD)
1802 offset -= SUBREG_WORD (setreg);
1803 setreg = SUBREG_REG (setreg);
1805 if (GET_CODE (setreg) != REG)
1807 sreg = REGNO (setreg);
1808 ssize = REG_SIZE (setreg);
1810 /* If UREG is a pseudo-register that hasn't already been assigned a
1811 quantity number, it means that it is not local to this block or dies
1812 more than once. In either event, we can't do anything with it. */
1813 if ((ureg >= FIRST_PSEUDO_REGISTER && reg_qty[ureg] < 0)
1814 /* Do not combine registers unless one fits within the other. */
1815 || (offset > 0 && usize + offset > ssize)
1816 || (offset < 0 && usize + offset < ssize)
1817 /* Do not combine with a smaller already-assigned object
1818 if that smaller object is already combined with something bigger. */
1819 || (ssize > usize && ureg >= FIRST_PSEUDO_REGISTER
1820 && usize < qty[reg_qty[ureg]].size)
1821 /* Can't combine if SREG is not a register we can allocate. */
1822 || (sreg >= FIRST_PSEUDO_REGISTER && reg_qty[sreg] == -1)
1823 /* Don't combine with a pseudo mentioned in a REG_NO_CONFLICT note.
1824 These have already been taken care of. This probably wouldn't
1825 combine anyway, but don't take any chances. */
1826 || (ureg >= FIRST_PSEUDO_REGISTER
1827 && find_reg_note (insn, REG_NO_CONFLICT, usedreg))
1828 /* Don't tie something to itself. In most cases it would make no
1829 difference, but it would screw up if the reg being tied to itself
1830 also dies in this insn. */
1832 /* Don't try to connect two different hardware registers. */
1833 || (ureg < FIRST_PSEUDO_REGISTER && sreg < FIRST_PSEUDO_REGISTER)
1834 /* Don't connect two different machine modes if they have different
1835 implications as to which registers may be used. */
1836 || !MODES_TIEABLE_P (GET_MODE (usedreg), GET_MODE (setreg)))
1839 /* Now, if UREG is a hard reg and SREG is a pseudo, record the hard reg in
1840 qty_phys_sugg for the pseudo instead of tying them.
1842 Return "failure" so that the lifespan of UREG is terminated here;
1843 that way the two lifespans will be disjoint and nothing will prevent
1844 the pseudo reg from being given this hard reg. */
1846 if (ureg < FIRST_PSEUDO_REGISTER)
1848 /* Allocate a quantity number so we have a place to put our
1850 if (reg_qty[sreg] == -2)
1851 reg_is_born (setreg, 2 * insn_number);
1853 if (reg_qty[sreg] >= 0)
1856 && ! TEST_HARD_REG_BIT (qty_phys_copy_sugg[reg_qty[sreg]], ureg))
1858 SET_HARD_REG_BIT (qty_phys_copy_sugg[reg_qty[sreg]], ureg);
1859 qty_phys_num_copy_sugg[reg_qty[sreg]]++;
1861 else if (! TEST_HARD_REG_BIT (qty_phys_sugg[reg_qty[sreg]], ureg))
1863 SET_HARD_REG_BIT (qty_phys_sugg[reg_qty[sreg]], ureg);
1864 qty_phys_num_sugg[reg_qty[sreg]]++;
1870 /* Similarly for SREG a hard register and UREG a pseudo register. */
1872 if (sreg < FIRST_PSEUDO_REGISTER)
1875 && ! TEST_HARD_REG_BIT (qty_phys_copy_sugg[reg_qty[ureg]], sreg))
1877 SET_HARD_REG_BIT (qty_phys_copy_sugg[reg_qty[ureg]], sreg);
1878 qty_phys_num_copy_sugg[reg_qty[ureg]]++;
1880 else if (! TEST_HARD_REG_BIT (qty_phys_sugg[reg_qty[ureg]], sreg))
1882 SET_HARD_REG_BIT (qty_phys_sugg[reg_qty[ureg]], sreg);
1883 qty_phys_num_sugg[reg_qty[ureg]]++;
1888 /* At this point we know that SREG and UREG are both pseudos.
1889 Do nothing if SREG already has a quantity or is a register that we
1891 if (reg_qty[sreg] >= -1
1892 /* If we are not going to let any regs live across calls,
1893 don't tie a call-crossing reg to a non-call-crossing reg. */
1894 || (current_function_has_nonlocal_label
1895 && ((REG_N_CALLS_CROSSED (ureg) > 0)
1896 != (REG_N_CALLS_CROSSED (sreg) > 0))))
1899 /* We don't already know about SREG, so tie it to UREG
1900 if this is the last use of UREG, provided the classes they want
1903 if ((already_dead || find_regno_note (insn, REG_DEAD, ureg))
1904 && reg_meets_class_p (sreg, qty[reg_qty[ureg]].min_class))
1906 /* Add SREG to UREG's quantity. */
1907 sqty = reg_qty[ureg];
1908 reg_qty[sreg] = sqty;
1909 reg_offset[sreg] = reg_offset[ureg] + offset;
1910 reg_next_in_qty[sreg] = qty[sqty].first_reg;
1911 qty[sqty].first_reg = sreg;
1913 /* If SREG's reg class is smaller, set qty[SQTY].min_class. */
1914 update_qty_class (sqty, sreg);
1916 /* Update info about quantity SQTY. */
1917 qty[sqty].n_calls_crossed += REG_N_CALLS_CROSSED (sreg);
1918 qty[sqty].n_refs += REG_N_REFS (sreg);
1923 for (i = qty[sqty].first_reg; i >= 0; i = reg_next_in_qty[i])
1924 reg_offset[i] -= offset;
1926 qty[sqty].size = ssize;
1927 qty[sqty].mode = GET_MODE (setreg);
1936 /* Return 1 if the preferred class of REG allows it to be tied
1937 to a quantity or register whose class is CLASS.
1938 True if REG's reg class either contains or is contained in CLASS. */
1941 reg_meets_class_p (reg, class)
1943 enum reg_class class;
1945 register enum reg_class rclass = reg_preferred_class (reg);
1946 return (reg_class_subset_p (rclass, class)
1947 || reg_class_subset_p (class, rclass));
1950 /* Update the class of QTYNO assuming that REG is being tied to it. */
1953 update_qty_class (qtyno, reg)
1957 enum reg_class rclass = reg_preferred_class (reg);
1958 if (reg_class_subset_p (rclass, qty[qtyno].min_class))
1959 qty[qtyno].min_class = rclass;
1961 rclass = reg_alternate_class (reg);
1962 if (reg_class_subset_p (rclass, qty[qtyno].alternate_class))
1963 qty[qtyno].alternate_class = rclass;
1965 if (REG_CHANGES_MODE (reg))
1966 qty[qtyno].changes_mode = 1;
1969 /* Handle something which alters the value of an rtx REG.
1971 REG is whatever is set or clobbered. SETTER is the rtx that
1972 is modifying the register.
1974 If it is not really a register, we do nothing.
1975 The file-global variables `this_insn' and `this_insn_number'
1976 carry info from `block_alloc'. */
1979 reg_is_set (reg, setter, data)
1982 void *data ATTRIBUTE_UNUSED;
1984 /* Note that note_stores will only pass us a SUBREG if it is a SUBREG of
1985 a hard register. These may actually not exist any more. */
1987 if (GET_CODE (reg) != SUBREG
1988 && GET_CODE (reg) != REG)
1991 /* Mark this register as being born. If it is used in a CLOBBER, mark
1992 it as being born halfway between the previous insn and this insn so that
1993 it conflicts with our inputs but not the outputs of the previous insn. */
1995 reg_is_born (reg, 2 * this_insn_number - (GET_CODE (setter) == CLOBBER));
1998 /* Handle beginning of the life of register REG.
1999 BIRTH is the index at which this is happening. */
2002 reg_is_born (reg, birth)
2008 if (GET_CODE (reg) == SUBREG)
2009 regno = REGNO (SUBREG_REG (reg)) + SUBREG_WORD (reg);
2011 regno = REGNO (reg);
2013 if (regno < FIRST_PSEUDO_REGISTER)
2015 mark_life (regno, GET_MODE (reg), 1);
2017 /* If the register was to have been born earlier that the present
2018 insn, mark it as live where it is actually born. */
2019 if (birth < 2 * this_insn_number)
2020 post_mark_life (regno, GET_MODE (reg), 1, birth, 2 * this_insn_number);
2024 if (reg_qty[regno] == -2)
2025 alloc_qty (regno, GET_MODE (reg), PSEUDO_REGNO_SIZE (regno), birth);
2027 /* If this register has a quantity number, show that it isn't dead. */
2028 if (reg_qty[regno] >= 0)
2029 qty[reg_qty[regno]].death = -1;
2033 /* Record the death of REG in the current insn. If OUTPUT_P is non-zero,
2034 REG is an output that is dying (i.e., it is never used), otherwise it
2035 is an input (the normal case).
2036 If OUTPUT_P is 1, then we extend the life past the end of this insn. */
2039 wipe_dead_reg (reg, output_p)
2043 register int regno = REGNO (reg);
2045 /* If this insn has multiple results,
2046 and the dead reg is used in one of the results,
2047 extend its life to after this insn,
2048 so it won't get allocated together with any other result of this insn.
2050 It is unsafe to use !single_set here since it will ignore an unused
2051 output. Just because an output is unused does not mean the compiler
2052 can assume the side effect will not occur. Consider if REG appears
2053 in the address of an output and we reload the output. If we allocate
2054 REG to the same hard register as an unused output we could set the hard
2055 register before the output reload insn. */
2056 if (GET_CODE (PATTERN (this_insn)) == PARALLEL
2057 && multiple_sets (this_insn))
2060 for (i = XVECLEN (PATTERN (this_insn), 0) - 1; i >= 0; i--)
2062 rtx set = XVECEXP (PATTERN (this_insn), 0, i);
2063 if (GET_CODE (set) == SET
2064 && GET_CODE (SET_DEST (set)) != REG
2065 && !rtx_equal_p (reg, SET_DEST (set))
2066 && reg_overlap_mentioned_p (reg, SET_DEST (set)))
2071 /* If this register is used in an auto-increment address, then extend its
2072 life to after this insn, so that it won't get allocated together with
2073 the result of this insn. */
2074 if (! output_p && find_regno_note (this_insn, REG_INC, regno))
2077 if (regno < FIRST_PSEUDO_REGISTER)
2079 mark_life (regno, GET_MODE (reg), 0);
2081 /* If a hard register is dying as an output, mark it as in use at
2082 the beginning of this insn (the above statement would cause this
2085 post_mark_life (regno, GET_MODE (reg), 1,
2086 2 * this_insn_number, 2 * this_insn_number + 1);
2089 else if (reg_qty[regno] >= 0)
2090 qty[reg_qty[regno]].death = 2 * this_insn_number + output_p;
2093 /* Find a block of SIZE words of hard regs in reg_class CLASS
2094 that can hold something of machine-mode MODE
2095 (but actually we test only the first of the block for holding MODE)
2096 and still free between insn BORN_INDEX and insn DEAD_INDEX,
2097 and return the number of the first of them.
2098 Return -1 if such a block cannot be found.
2099 If QTYNO crosses calls, insist on a register preserved by calls,
2100 unless ACCEPT_CALL_CLOBBERED is nonzero.
2102 If JUST_TRY_SUGGESTED is non-zero, only try to see if the suggested
2103 register is available. If not, return -1. */
2106 find_free_reg (class, mode, qtyno, accept_call_clobbered, just_try_suggested,
2107 born_index, dead_index)
2108 enum reg_class class;
2109 enum machine_mode mode;
2111 int accept_call_clobbered;
2112 int just_try_suggested;
2113 int born_index, dead_index;
2115 register int i, ins;
2117 /* Declare it register if it's a scalar. */
2120 HARD_REG_SET used, first_used;
2121 #ifdef ELIMINABLE_REGS
2122 static struct {int from, to; } eliminables[] = ELIMINABLE_REGS;
2125 /* Validate our parameters. */
2126 if (born_index < 0 || born_index > dead_index)
2129 /* Don't let a pseudo live in a reg across a function call
2130 if we might get a nonlocal goto. */
2131 if (current_function_has_nonlocal_label
2132 && qty[qtyno].n_calls_crossed > 0)
2135 if (accept_call_clobbered)
2136 COPY_HARD_REG_SET (used, call_fixed_reg_set);
2137 else if (qty[qtyno].n_calls_crossed == 0)
2138 COPY_HARD_REG_SET (used, fixed_reg_set);
2140 COPY_HARD_REG_SET (used, call_used_reg_set);
2142 if (accept_call_clobbered)
2143 IOR_HARD_REG_SET (used, losing_caller_save_reg_set);
2145 for (ins = born_index; ins < dead_index; ins++)
2146 IOR_HARD_REG_SET (used, regs_live_at[ins]);
2148 IOR_COMPL_HARD_REG_SET (used, reg_class_contents[(int) class]);
2150 /* Don't use the frame pointer reg in local-alloc even if
2151 we may omit the frame pointer, because if we do that and then we
2152 need a frame pointer, reload won't know how to move the pseudo
2153 to another hard reg. It can move only regs made by global-alloc.
2155 This is true of any register that can be eliminated. */
2156 #ifdef ELIMINABLE_REGS
2157 for (i = 0; i < (int) ARRAY_SIZE (eliminables); i++)
2158 SET_HARD_REG_BIT (used, eliminables[i].from);
2159 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2160 /* If FRAME_POINTER_REGNUM is not a real register, then protect the one
2161 that it might be eliminated into. */
2162 SET_HARD_REG_BIT (used, HARD_FRAME_POINTER_REGNUM);
2165 SET_HARD_REG_BIT (used, FRAME_POINTER_REGNUM);
2168 #ifdef CLASS_CANNOT_CHANGE_MODE
2169 if (qty[qtyno].changes_mode)
2170 IOR_HARD_REG_SET (used,
2171 reg_class_contents[(int) CLASS_CANNOT_CHANGE_MODE]);
2174 /* Normally, the registers that can be used for the first register in
2175 a multi-register quantity are the same as those that can be used for
2176 subsequent registers. However, if just trying suggested registers,
2177 restrict our consideration to them. If there are copy-suggested
2178 register, try them. Otherwise, try the arithmetic-suggested
2180 COPY_HARD_REG_SET (first_used, used);
2182 if (just_try_suggested)
2184 if (qty_phys_num_copy_sugg[qtyno] != 0)
2185 IOR_COMPL_HARD_REG_SET (first_used, qty_phys_copy_sugg[qtyno]);
2187 IOR_COMPL_HARD_REG_SET (first_used, qty_phys_sugg[qtyno]);
2190 /* If all registers are excluded, we can't do anything. */
2191 GO_IF_HARD_REG_SUBSET (reg_class_contents[(int) ALL_REGS], first_used, fail);
2193 /* If at least one would be suitable, test each hard reg. */
2195 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
2197 #ifdef REG_ALLOC_ORDER
2198 int regno = reg_alloc_order[i];
2202 if (! TEST_HARD_REG_BIT (first_used, regno)
2203 && HARD_REGNO_MODE_OK (regno, mode)
2204 && (qty[qtyno].n_calls_crossed == 0
2205 || accept_call_clobbered
2206 || ! HARD_REGNO_CALL_PART_CLOBBERED (regno, mode)))
2209 register int size1 = HARD_REGNO_NREGS (regno, mode);
2210 for (j = 1; j < size1 && ! TEST_HARD_REG_BIT (used, regno + j); j++);
2213 /* Mark that this register is in use between its birth and death
2215 post_mark_life (regno, mode, 1, born_index, dead_index);
2218 #ifndef REG_ALLOC_ORDER
2219 /* Skip starting points we know will lose. */
2226 /* If we are just trying suggested register, we have just tried copy-
2227 suggested registers, and there are arithmetic-suggested registers,
2230 /* If it would be profitable to allocate a call-clobbered register
2231 and save and restore it around calls, do that. */
2232 if (just_try_suggested && qty_phys_num_copy_sugg[qtyno] != 0
2233 && qty_phys_num_sugg[qtyno] != 0)
2235 /* Don't try the copy-suggested regs again. */
2236 qty_phys_num_copy_sugg[qtyno] = 0;
2237 return find_free_reg (class, mode, qtyno, accept_call_clobbered, 1,
2238 born_index, dead_index);
2241 /* We need not check to see if the current function has nonlocal
2242 labels because we don't put any pseudos that are live over calls in
2243 registers in that case. */
2245 if (! accept_call_clobbered
2246 && flag_caller_saves
2247 && ! just_try_suggested
2248 && qty[qtyno].n_calls_crossed != 0
2249 && CALLER_SAVE_PROFITABLE (qty[qtyno].n_refs,
2250 qty[qtyno].n_calls_crossed))
2252 i = find_free_reg (class, mode, qtyno, 1, 0, born_index, dead_index);
2254 caller_save_needed = 1;
2260 /* Mark that REGNO with machine-mode MODE is live starting from the current
2261 insn (if LIFE is non-zero) or dead starting at the current insn (if LIFE
2265 mark_life (regno, mode, life)
2267 enum machine_mode mode;
2270 register int j = HARD_REGNO_NREGS (regno, mode);
2273 SET_HARD_REG_BIT (regs_live, regno + j);
2276 CLEAR_HARD_REG_BIT (regs_live, regno + j);
2279 /* Mark register number REGNO (with machine-mode MODE) as live (if LIFE
2280 is non-zero) or dead (if LIFE is zero) from insn number BIRTH (inclusive)
2281 to insn number DEATH (exclusive). */
2284 post_mark_life (regno, mode, life, birth, death)
2286 enum machine_mode mode;
2287 int life, birth, death;
2289 register int j = HARD_REGNO_NREGS (regno, mode);
2291 /* Declare it register if it's a scalar. */
2294 HARD_REG_SET this_reg;
2296 CLEAR_HARD_REG_SET (this_reg);
2298 SET_HARD_REG_BIT (this_reg, regno + j);
2301 while (birth < death)
2303 IOR_HARD_REG_SET (regs_live_at[birth], this_reg);
2307 while (birth < death)
2309 AND_COMPL_HARD_REG_SET (regs_live_at[birth], this_reg);
2314 /* INSN is the CLOBBER insn that starts a REG_NO_NOCONFLICT block, R0
2315 is the register being clobbered, and R1 is a register being used in
2316 the equivalent expression.
2318 If R1 dies in the block and has a REG_NO_CONFLICT note on every insn
2319 in which it is used, return 1.
2321 Otherwise, return 0. */
2324 no_conflict_p (insn, r0, r1)
2325 rtx insn, r0 ATTRIBUTE_UNUSED, r1;
2328 rtx note = find_reg_note (insn, REG_LIBCALL, NULL_RTX);
2331 /* If R1 is a hard register, return 0 since we handle this case
2332 when we scan the insns that actually use it. */
2335 || (GET_CODE (r1) == REG && REGNO (r1) < FIRST_PSEUDO_REGISTER)
2336 || (GET_CODE (r1) == SUBREG && GET_CODE (SUBREG_REG (r1)) == REG
2337 && REGNO (SUBREG_REG (r1)) < FIRST_PSEUDO_REGISTER))
2340 last = XEXP (note, 0);
2342 for (p = NEXT_INSN (insn); p && p != last; p = NEXT_INSN (p))
2345 if (find_reg_note (p, REG_DEAD, r1))
2348 /* There must be a REG_NO_CONFLICT note on every insn, otherwise
2349 some earlier optimization pass has inserted instructions into
2350 the sequence, and it is not safe to perform this optimization.
2351 Note that emit_no_conflict_block always ensures that this is
2352 true when these sequences are created. */
2353 if (! find_reg_note (p, REG_NO_CONFLICT, r1))
2360 /* Return the number of alternatives for which the constraint string P
2361 indicates that the operand must be equal to operand 0 and that no register
2370 int reg_allowed = 0;
2371 int num_matching_alts = 0;
2376 case '=': case '+': case '?':
2377 case '#': case '&': case '!':
2379 case '1': case '2': case '3': case '4': case '5':
2380 case '6': case '7': case '8': case '9':
2381 case 'm': case '<': case '>': case 'V': case 'o':
2382 case 'E': case 'F': case 'G': case 'H':
2383 case 's': case 'i': case 'n':
2384 case 'I': case 'J': case 'K': case 'L':
2385 case 'M': case 'N': case 'O': case 'P':
2387 /* These don't say anything we care about. */
2391 if (found_zero && ! reg_allowed)
2392 num_matching_alts++;
2394 found_zero = reg_allowed = 0;
2402 if (REG_CLASS_FROM_LETTER (c) == NO_REGS)
2411 if (found_zero && ! reg_allowed)
2412 num_matching_alts++;
2414 return num_matching_alts;
2418 dump_local_alloc (file)
2422 for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
2423 if (reg_renumber[i] != -1)
2424 fprintf (file, ";; Register %d in %d.\n", i, reg_renumber[i]);