1 /* RTL-level loop invariant motion.
2 Copyright (C) 2004-2015 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published by the
8 Free Software Foundation; either version 3, or (at your option) any
11 GCC is distributed in the hope that it will be useful, but WITHOUT
12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
20 /* This implements the loop invariant motion pass. It is very simple
21 (no calls, no loads/stores, etc.). This should be sufficient to cleanup
22 things like address arithmetics -- other more complicated invariants should
23 be eliminated on GIMPLE either in tree-ssa-loop-im.c or in tree-ssa-pre.c.
25 We proceed loop by loop -- it is simpler than trying to handle things
26 globally and should not lose much. First we inspect all sets inside loop
27 and create a dependency graph on insns (saying "to move this insn, you must
28 also move the following insns").
30 We then need to determine what to move. We estimate the number of registers
31 used and move as many invariants as possible while we still have enough free
32 registers. We prefer the expensive invariants.
34 Then we move the selected invariants out of the loop, creating a new
35 temporaries for them if necessary. */
39 #include "coretypes.h"
41 #include "hard-reg-set.h"
52 #include "dominance.h"
55 #include "basic-block.h"
59 #include "statistics.h"
60 #include "double-int.h"
62 #include "fixed-value.h"
67 #include "insn-config.h"
79 #include "hash-table.h"
86 /* The data stored for the loop. */
90 struct loop
*outermost_exit
; /* The outermost exit of the loop. */
91 bool has_call
; /* True if the loop contains a call. */
92 /* Maximal register pressure inside loop for given register class
93 (defined only for the pressure classes). */
94 int max_reg_pressure
[N_REG_CLASSES
];
95 /* Loop regs referenced and live pseudo-registers. */
97 bitmap_head regs_live
;
100 #define LOOP_DATA(LOOP) ((struct loop_data *) (LOOP)->aux)
102 /* The description of an use. */
106 rtx
*pos
; /* Position of the use. */
107 rtx_insn
*insn
; /* The insn in that the use occurs. */
108 unsigned addr_use_p
; /* Whether the use occurs in an address. */
109 struct use
*next
; /* Next use in the list. */
112 /* The description of a def. */
116 struct use
*uses
; /* The list of uses that are uniquely reached
118 unsigned n_uses
; /* Number of such uses. */
119 unsigned n_addr_uses
; /* Number of uses in addresses. */
120 unsigned invno
; /* The corresponding invariant. */
123 /* The data stored for each invariant. */
127 /* The number of the invariant. */
130 /* The number of the invariant with the same value. */
133 /* The number of invariants which eqto this. */
136 /* If we moved the invariant out of the loop, the register that contains its
140 /* If we moved the invariant out of the loop, the original regno
141 that contained its value. */
144 /* The definition of the invariant. */
147 /* The insn in that it is defined. */
150 /* Whether it is always executed. */
151 bool always_executed
;
153 /* Whether to move the invariant. */
156 /* Whether the invariant is cheap when used as an address. */
159 /* Cost of the invariant. */
162 /* The invariants it depends on. */
165 /* Used for detecting already visited invariants during determining
166 costs of movements. */
170 /* Currently processed loop. */
171 static struct loop
*curr_loop
;
173 /* Table of invariants indexed by the df_ref uid field. */
175 static unsigned int invariant_table_size
= 0;
176 static struct invariant
** invariant_table
;
178 /* Entry for hash table of invariant expressions. */
180 struct invariant_expr_entry
183 struct invariant
*inv
;
195 /* The actual stamp for marking already visited invariants during determining
196 costs of movements. */
198 static unsigned actual_stamp
;
200 typedef struct invariant
*invariant_p
;
203 /* The invariants. */
205 static vec
<invariant_p
> invariants
;
207 /* Check the size of the invariant table and realloc if necessary. */
210 check_invariant_table_size (void)
212 if (invariant_table_size
< DF_DEFS_TABLE_SIZE ())
214 unsigned int new_size
= DF_DEFS_TABLE_SIZE () + (DF_DEFS_TABLE_SIZE () / 4);
215 invariant_table
= XRESIZEVEC (struct invariant
*, invariant_table
, new_size
);
216 memset (&invariant_table
[invariant_table_size
], 0,
217 (new_size
- invariant_table_size
) * sizeof (struct invariant
*));
218 invariant_table_size
= new_size
;
222 /* Test for possibility of invariantness of X. */
225 check_maybe_invariant (rtx x
)
227 enum rtx_code code
= GET_CODE (x
);
241 case UNSPEC_VOLATILE
:
249 /* Load/store motion is done elsewhere. ??? Perhaps also add it here?
250 It should not be hard, and might be faster than "elsewhere". */
252 /* Just handle the most trivial case where we load from an unchanging
253 location (most importantly, pic tables). */
254 if (MEM_READONLY_P (x
) && !MEM_VOLATILE_P (x
))
260 /* Don't mess with insns declared volatile. */
261 if (MEM_VOLATILE_P (x
))
269 fmt
= GET_RTX_FORMAT (code
);
270 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
274 if (!check_maybe_invariant (XEXP (x
, i
)))
277 else if (fmt
[i
] == 'E')
279 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
280 if (!check_maybe_invariant (XVECEXP (x
, i
, j
)))
288 /* Returns the invariant definition for USE, or NULL if USE is not
291 static struct invariant
*
292 invariant_for_use (df_ref use
)
294 struct df_link
*defs
;
296 basic_block bb
= DF_REF_BB (use
), def_bb
;
298 if (DF_REF_FLAGS (use
) & DF_REF_READ_WRITE
)
301 defs
= DF_REF_CHAIN (use
);
302 if (!defs
|| defs
->next
)
305 check_invariant_table_size ();
306 if (!invariant_table
[DF_REF_ID (def
)])
309 def_bb
= DF_REF_BB (def
);
310 if (!dominated_by_p (CDI_DOMINATORS
, bb
, def_bb
))
312 return invariant_table
[DF_REF_ID (def
)];
315 /* Computes hash value for invariant expression X in INSN. */
318 hash_invariant_expr_1 (rtx_insn
*insn
, rtx x
)
320 enum rtx_code code
= GET_CODE (x
);
323 hashval_t val
= code
;
326 struct invariant
*inv
;
334 return hash_rtx (x
, GET_MODE (x
), &do_not_record_p
, NULL
, false);
337 use
= df_find_use (insn
, x
);
339 return hash_rtx (x
, GET_MODE (x
), &do_not_record_p
, NULL
, false);
340 inv
= invariant_for_use (use
);
342 return hash_rtx (x
, GET_MODE (x
), &do_not_record_p
, NULL
, false);
344 gcc_assert (inv
->eqto
!= ~0u);
351 fmt
= GET_RTX_FORMAT (code
);
352 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
355 val
^= hash_invariant_expr_1 (insn
, XEXP (x
, i
));
356 else if (fmt
[i
] == 'E')
358 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
359 val
^= hash_invariant_expr_1 (insn
, XVECEXP (x
, i
, j
));
361 else if (fmt
[i
] == 'i' || fmt
[i
] == 'n')
368 /* Returns true if the invariant expressions E1 and E2 used in insns INSN1
369 and INSN2 have always the same value. */
372 invariant_expr_equal_p (rtx_insn
*insn1
, rtx e1
, rtx_insn
*insn2
, rtx e2
)
374 enum rtx_code code
= GET_CODE (e1
);
378 struct invariant
*inv1
= NULL
, *inv2
= NULL
;
381 /* If mode of only one of the operands is VOIDmode, it is not equivalent to
382 the other one. If both are VOIDmode, we rely on the caller of this
383 function to verify that their modes are the same. */
384 if (code
!= GET_CODE (e2
) || GET_MODE (e1
) != GET_MODE (e2
))
393 return rtx_equal_p (e1
, e2
);
396 use1
= df_find_use (insn1
, e1
);
397 use2
= df_find_use (insn2
, e2
);
399 inv1
= invariant_for_use (use1
);
401 inv2
= invariant_for_use (use2
);
404 return rtx_equal_p (e1
, e2
);
409 gcc_assert (inv1
->eqto
!= ~0u);
410 gcc_assert (inv2
->eqto
!= ~0u);
411 return inv1
->eqto
== inv2
->eqto
;
417 fmt
= GET_RTX_FORMAT (code
);
418 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
425 if (!invariant_expr_equal_p (insn1
, sub1
, insn2
, sub2
))
429 else if (fmt
[i
] == 'E')
431 if (XVECLEN (e1
, i
) != XVECLEN (e2
, i
))
434 for (j
= 0; j
< XVECLEN (e1
, i
); j
++)
436 sub1
= XVECEXP (e1
, i
, j
);
437 sub2
= XVECEXP (e2
, i
, j
);
439 if (!invariant_expr_equal_p (insn1
, sub1
, insn2
, sub2
))
443 else if (fmt
[i
] == 'i' || fmt
[i
] == 'n')
445 if (XINT (e1
, i
) != XINT (e2
, i
))
448 /* Unhandled type of subexpression, we fail conservatively. */
456 struct invariant_expr_hasher
: typed_free_remove
<invariant_expr_entry
>
458 typedef invariant_expr_entry
*value_type
;
459 typedef invariant_expr_entry
*compare_type
;
460 static inline hashval_t
hash (const invariant_expr_entry
*);
461 static inline bool equal (const invariant_expr_entry
*,
462 const invariant_expr_entry
*);
465 /* Returns hash value for invariant expression entry ENTRY. */
468 invariant_expr_hasher::hash (const invariant_expr_entry
*entry
)
473 /* Compares invariant expression entries ENTRY1 and ENTRY2. */
476 invariant_expr_hasher::equal (const invariant_expr_entry
*entry1
,
477 const invariant_expr_entry
*entry2
)
479 if (entry1
->mode
!= entry2
->mode
)
482 return invariant_expr_equal_p (entry1
->inv
->insn
, entry1
->expr
,
483 entry2
->inv
->insn
, entry2
->expr
);
486 typedef hash_table
<invariant_expr_hasher
> invariant_htab_type
;
488 /* Checks whether invariant with value EXPR in machine mode MODE is
489 recorded in EQ. If this is the case, return the invariant. Otherwise
490 insert INV to the table for this expression and return INV. */
492 static struct invariant
*
493 find_or_insert_inv (invariant_htab_type
*eq
, rtx expr
, machine_mode mode
,
494 struct invariant
*inv
)
496 hashval_t hash
= hash_invariant_expr_1 (inv
->insn
, expr
);
497 struct invariant_expr_entry
*entry
;
498 struct invariant_expr_entry pentry
;
499 invariant_expr_entry
**slot
;
504 slot
= eq
->find_slot_with_hash (&pentry
, hash
, INSERT
);
510 entry
= XNEW (struct invariant_expr_entry
);
520 /* Finds invariants identical to INV and records the equivalence. EQ is the
521 hash table of the invariants. */
524 find_identical_invariants (invariant_htab_type
*eq
, struct invariant
*inv
)
528 struct invariant
*dep
;
531 struct invariant
*tmp
;
533 if (inv
->eqto
!= ~0u)
536 EXECUTE_IF_SET_IN_BITMAP (inv
->depends_on
, 0, depno
, bi
)
538 dep
= invariants
[depno
];
539 find_identical_invariants (eq
, dep
);
542 set
= single_set (inv
->insn
);
543 expr
= SET_SRC (set
);
544 mode
= GET_MODE (expr
);
545 if (mode
== VOIDmode
)
546 mode
= GET_MODE (SET_DEST (set
));
548 tmp
= find_or_insert_inv (eq
, expr
, mode
, inv
);
549 inv
->eqto
= tmp
->invno
;
551 if (tmp
->invno
!= inv
->invno
&& inv
->always_executed
)
554 if (dump_file
&& inv
->eqto
!= inv
->invno
)
556 "Invariant %d is equivalent to invariant %d.\n",
557 inv
->invno
, inv
->eqto
);
560 /* Find invariants with the same value and record the equivalences. */
563 merge_identical_invariants (void)
566 struct invariant
*inv
;
567 invariant_htab_type
eq (invariants
.length ());
569 FOR_EACH_VEC_ELT (invariants
, i
, inv
)
570 find_identical_invariants (&eq
, inv
);
573 /* Determines the basic blocks inside LOOP that are always executed and
574 stores their bitmap to ALWAYS_REACHED. MAY_EXIT is a bitmap of
575 basic blocks that may either exit the loop, or contain the call that
576 does not have to return. BODY is body of the loop obtained by
577 get_loop_body_in_dom_order. */
580 compute_always_reached (struct loop
*loop
, basic_block
*body
,
581 bitmap may_exit
, bitmap always_reached
)
585 for (i
= 0; i
< loop
->num_nodes
; i
++)
587 if (dominated_by_p (CDI_DOMINATORS
, loop
->latch
, body
[i
]))
588 bitmap_set_bit (always_reached
, i
);
590 if (bitmap_bit_p (may_exit
, i
))
595 /* Finds exits out of the LOOP with body BODY. Marks blocks in that we may
596 exit the loop by cfg edge to HAS_EXIT and MAY_EXIT. In MAY_EXIT
597 additionally mark blocks that may exit due to a call. */
600 find_exits (struct loop
*loop
, basic_block
*body
,
601 bitmap may_exit
, bitmap has_exit
)
606 struct loop
*outermost_exit
= loop
, *aexit
;
607 bool has_call
= false;
610 for (i
= 0; i
< loop
->num_nodes
; i
++)
612 if (body
[i
]->loop_father
== loop
)
614 FOR_BB_INSNS (body
[i
], insn
)
617 && (RTL_LOOPING_CONST_OR_PURE_CALL_P (insn
)
618 || !RTL_CONST_OR_PURE_CALL_P (insn
)))
621 bitmap_set_bit (may_exit
, i
);
626 FOR_EACH_EDGE (e
, ei
, body
[i
]->succs
)
628 if (flow_bb_inside_loop_p (loop
, e
->dest
))
631 bitmap_set_bit (may_exit
, i
);
632 bitmap_set_bit (has_exit
, i
);
633 outermost_exit
= find_common_loop (outermost_exit
,
634 e
->dest
->loop_father
);
639 /* Use the data stored for the subloop to decide whether we may exit
640 through it. It is sufficient to do this for header of the loop,
641 as other basic blocks inside it must be dominated by it. */
642 if (body
[i
]->loop_father
->header
!= body
[i
])
645 if (LOOP_DATA (body
[i
]->loop_father
)->has_call
)
648 bitmap_set_bit (may_exit
, i
);
650 aexit
= LOOP_DATA (body
[i
]->loop_father
)->outermost_exit
;
653 bitmap_set_bit (may_exit
, i
);
654 bitmap_set_bit (has_exit
, i
);
656 if (flow_loop_nested_p (aexit
, outermost_exit
))
657 outermost_exit
= aexit
;
661 if (loop
->aux
== NULL
)
663 loop
->aux
= xcalloc (1, sizeof (struct loop_data
));
664 bitmap_initialize (&LOOP_DATA (loop
)->regs_ref
, ®_obstack
);
665 bitmap_initialize (&LOOP_DATA (loop
)->regs_live
, ®_obstack
);
667 LOOP_DATA (loop
)->outermost_exit
= outermost_exit
;
668 LOOP_DATA (loop
)->has_call
= has_call
;
671 /* Check whether we may assign a value to X from a register. */
674 may_assign_reg_p (rtx x
)
676 return (GET_MODE (x
) != VOIDmode
677 && GET_MODE (x
) != BLKmode
678 && can_copy_p (GET_MODE (x
))
680 || !HARD_REGISTER_P (x
)
681 || REGNO_REG_CLASS (REGNO (x
)) != NO_REGS
));
684 /* Finds definitions that may correspond to invariants in LOOP with body
688 find_defs (struct loop
*loop
)
693 "*****starting processing of loop %d ******\n",
697 df_remove_problem (df_chain
);
698 df_process_deferred_rescans ();
699 df_chain_add_problem (DF_UD_CHAIN
);
700 df_set_flags (DF_RD_PRUNE_DEAD_DEFS
);
701 df_analyze_loop (loop
);
702 check_invariant_table_size ();
706 df_dump_region (dump_file
);
708 "*****ending processing of loop %d ******\n",
713 /* Creates a new invariant for definition DEF in INSN, depending on invariants
714 in DEPENDS_ON. ALWAYS_EXECUTED is true if the insn is always executed,
715 unless the program ends due to a function call. The newly created invariant
718 static struct invariant
*
719 create_new_invariant (struct def
*def
, rtx_insn
*insn
, bitmap depends_on
,
720 bool always_executed
)
722 struct invariant
*inv
= XNEW (struct invariant
);
723 rtx set
= single_set (insn
);
724 bool speed
= optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn
));
727 inv
->always_executed
= always_executed
;
728 inv
->depends_on
= depends_on
;
730 /* If the set is simple, usually by moving it we move the whole store out of
731 the loop. Otherwise we save only cost of the computation. */
734 inv
->cost
= set_rtx_cost (set
, speed
);
735 /* ??? Try to determine cheapness of address computation. Unfortunately
736 the address cost is only a relative measure, we can't really compare
737 it with any absolute number, but only with other address costs.
738 But here we don't have any other addresses, so compare with a magic
739 number anyway. It has to be large enough to not regress PR33928
740 (by avoiding to move reg+8,reg+16,reg+24 invariants), but small
741 enough to not regress 410.bwaves either (by still moving reg+reg
743 See http://gcc.gnu.org/ml/gcc-patches/2009-10/msg01210.html . */
744 inv
->cheap_address
= address_cost (SET_SRC (set
), word_mode
,
745 ADDR_SPACE_GENERIC
, speed
) < 3;
749 inv
->cost
= set_src_cost (SET_SRC (set
), speed
);
750 inv
->cheap_address
= false;
755 inv
->orig_regno
= -1;
759 inv
->invno
= invariants
.length ();
766 def
->invno
= inv
->invno
;
767 invariants
.safe_push (inv
);
772 "Set in insn %d is invariant (%d), cost %d, depends on ",
773 INSN_UID (insn
), inv
->invno
, inv
->cost
);
774 dump_bitmap (dump_file
, inv
->depends_on
);
780 /* Record USE at DEF. */
783 record_use (struct def
*def
, df_ref use
)
785 struct use
*u
= XNEW (struct use
);
787 u
->pos
= DF_REF_REAL_LOC (use
);
788 u
->insn
= DF_REF_INSN (use
);
789 u
->addr_use_p
= (DF_REF_TYPE (use
) == DF_REF_REG_MEM_LOAD
790 || DF_REF_TYPE (use
) == DF_REF_REG_MEM_STORE
);
798 /* Finds the invariants USE depends on and store them to the DEPENDS_ON
799 bitmap. Returns true if all dependencies of USE are known to be
800 loop invariants, false otherwise. */
803 check_dependency (basic_block bb
, df_ref use
, bitmap depends_on
)
807 struct df_link
*defs
;
808 struct def
*def_data
;
809 struct invariant
*inv
;
811 if (DF_REF_FLAGS (use
) & DF_REF_READ_WRITE
)
814 defs
= DF_REF_CHAIN (use
);
817 unsigned int regno
= DF_REF_REGNO (use
);
819 /* If this is the use of an uninitialized argument register that is
820 likely to be spilled, do not move it lest this might extend its
821 lifetime and cause reload to die. This can occur for a call to
822 a function taking complex number arguments and moving the insns
823 preparing the arguments without moving the call itself wouldn't
824 gain much in practice. */
825 if ((DF_REF_FLAGS (use
) & DF_HARD_REG_LIVE
)
826 && FUNCTION_ARG_REGNO_P (regno
)
827 && targetm
.class_likely_spilled_p (REGNO_REG_CLASS (regno
)))
837 check_invariant_table_size ();
838 inv
= invariant_table
[DF_REF_ID (def
)];
843 gcc_assert (def_data
!= NULL
);
845 def_bb
= DF_REF_BB (def
);
846 /* Note that in case bb == def_bb, we know that the definition
847 dominates insn, because def has invariant_table[DF_REF_ID(def)]
848 defined and we process the insns in the basic block bb
850 if (!dominated_by_p (CDI_DOMINATORS
, bb
, def_bb
))
853 bitmap_set_bit (depends_on
, def_data
->invno
);
858 /* Finds the invariants INSN depends on and store them to the DEPENDS_ON
859 bitmap. Returns true if all dependencies of INSN are known to be
860 loop invariants, false otherwise. */
863 check_dependencies (rtx_insn
*insn
, bitmap depends_on
)
865 struct df_insn_info
*insn_info
= DF_INSN_INFO_GET (insn
);
867 basic_block bb
= BLOCK_FOR_INSN (insn
);
869 FOR_EACH_INSN_INFO_USE (use
, insn_info
)
870 if (!check_dependency (bb
, use
, depends_on
))
872 FOR_EACH_INSN_INFO_EQ_USE (use
, insn_info
)
873 if (!check_dependency (bb
, use
, depends_on
))
879 /* Pre-check candidate DEST to skip the one which can not make a valid insn
880 during move_invariant_reg. SIMPLE is to skip HARD_REGISTER. */
882 pre_check_invariant_p (bool simple
, rtx dest
)
884 if (simple
&& REG_P (dest
) && DF_REG_DEF_COUNT (REGNO (dest
)) > 1)
888 unsigned int i
= REGNO (dest
);
889 struct df_insn_info
*insn_info
;
892 for (use
= DF_REG_USE_CHAIN (i
); use
; use
= DF_REF_NEXT_REG (use
))
894 ref
= DF_REF_INSN (use
);
895 insn_info
= DF_INSN_INFO_GET (ref
);
897 FOR_EACH_INSN_INFO_DEF (def_rec
, insn_info
)
898 if (DF_REF_REGNO (def_rec
) == i
)
900 /* Multi definitions at this stage, most likely are due to
901 instruction constraints, which requires both read and write
902 on the same register. Since move_invariant_reg is not
903 powerful enough to handle such cases, just ignore the INV
904 and leave the chance to others. */
912 /* Finds invariant in INSN. ALWAYS_REACHED is true if the insn is always
913 executed. ALWAYS_EXECUTED is true if the insn is always executed,
914 unless the program ends due to a function call. */
917 find_invariant_insn (rtx_insn
*insn
, bool always_reached
, bool always_executed
)
924 struct invariant
*inv
;
927 /* We can't move a CC0 setter without the user. */
928 if (sets_cc0_p (insn
))
932 set
= single_set (insn
);
935 dest
= SET_DEST (set
);
938 || HARD_REGISTER_P (dest
))
941 if (!may_assign_reg_p (dest
)
942 || !pre_check_invariant_p (simple
, dest
)
943 || !check_maybe_invariant (SET_SRC (set
)))
946 /* If the insn can throw exception, we cannot move it at all without changing
948 if (can_throw_internal (insn
))
951 /* We cannot make trapping insn executed, unless it was executed before. */
952 if (may_trap_or_fault_p (PATTERN (insn
)) && !always_reached
)
955 depends_on
= BITMAP_ALLOC (NULL
);
956 if (!check_dependencies (insn
, depends_on
))
958 BITMAP_FREE (depends_on
);
963 def
= XCNEW (struct def
);
967 inv
= create_new_invariant (def
, insn
, depends_on
, always_executed
);
971 ref
= df_find_def (insn
, dest
);
972 check_invariant_table_size ();
973 invariant_table
[DF_REF_ID (ref
)] = inv
;
977 /* Record registers used in INSN that have a unique invariant definition. */
980 record_uses (rtx_insn
*insn
)
982 struct df_insn_info
*insn_info
= DF_INSN_INFO_GET (insn
);
984 struct invariant
*inv
;
986 FOR_EACH_INSN_INFO_USE (use
, insn_info
)
988 inv
= invariant_for_use (use
);
990 record_use (inv
->def
, use
);
992 FOR_EACH_INSN_INFO_EQ_USE (use
, insn_info
)
994 inv
= invariant_for_use (use
);
996 record_use (inv
->def
, use
);
1000 /* Finds invariants in INSN. ALWAYS_REACHED is true if the insn is always
1001 executed. ALWAYS_EXECUTED is true if the insn is always executed,
1002 unless the program ends due to a function call. */
1005 find_invariants_insn (rtx_insn
*insn
, bool always_reached
, bool always_executed
)
1007 find_invariant_insn (insn
, always_reached
, always_executed
);
1011 /* Finds invariants in basic block BB. ALWAYS_REACHED is true if the
1012 basic block is always executed. ALWAYS_EXECUTED is true if the basic
1013 block is always executed, unless the program ends due to a function
1017 find_invariants_bb (basic_block bb
, bool always_reached
, bool always_executed
)
1021 FOR_BB_INSNS (bb
, insn
)
1023 if (!NONDEBUG_INSN_P (insn
))
1026 find_invariants_insn (insn
, always_reached
, always_executed
);
1030 && (RTL_LOOPING_CONST_OR_PURE_CALL_P (insn
)
1031 || ! RTL_CONST_OR_PURE_CALL_P (insn
)))
1032 always_reached
= false;
1036 /* Finds invariants in LOOP with body BODY. ALWAYS_REACHED is the bitmap of
1037 basic blocks in BODY that are always executed. ALWAYS_EXECUTED is the
1038 bitmap of basic blocks in BODY that are always executed unless the program
1039 ends due to a function call. */
1042 find_invariants_body (struct loop
*loop
, basic_block
*body
,
1043 bitmap always_reached
, bitmap always_executed
)
1047 for (i
= 0; i
< loop
->num_nodes
; i
++)
1048 find_invariants_bb (body
[i
],
1049 bitmap_bit_p (always_reached
, i
),
1050 bitmap_bit_p (always_executed
, i
));
1053 /* Finds invariants in LOOP. */
1056 find_invariants (struct loop
*loop
)
1058 bitmap may_exit
= BITMAP_ALLOC (NULL
);
1059 bitmap always_reached
= BITMAP_ALLOC (NULL
);
1060 bitmap has_exit
= BITMAP_ALLOC (NULL
);
1061 bitmap always_executed
= BITMAP_ALLOC (NULL
);
1062 basic_block
*body
= get_loop_body_in_dom_order (loop
);
1064 find_exits (loop
, body
, may_exit
, has_exit
);
1065 compute_always_reached (loop
, body
, may_exit
, always_reached
);
1066 compute_always_reached (loop
, body
, has_exit
, always_executed
);
1069 find_invariants_body (loop
, body
, always_reached
, always_executed
);
1070 merge_identical_invariants ();
1072 BITMAP_FREE (always_reached
);
1073 BITMAP_FREE (always_executed
);
1074 BITMAP_FREE (may_exit
);
1075 BITMAP_FREE (has_exit
);
1079 /* Frees a list of uses USE. */
1082 free_use_list (struct use
*use
)
1086 for (; use
; use
= next
)
1093 /* Return pressure class and number of hard registers (through *NREGS)
1094 for destination of INSN. */
1095 static enum reg_class
1096 get_pressure_class_and_nregs (rtx_insn
*insn
, int *nregs
)
1099 enum reg_class pressure_class
;
1100 rtx set
= single_set (insn
);
1102 /* Considered invariant insns have only one set. */
1103 gcc_assert (set
!= NULL_RTX
);
1104 reg
= SET_DEST (set
);
1105 if (GET_CODE (reg
) == SUBREG
)
1106 reg
= SUBREG_REG (reg
);
1110 pressure_class
= NO_REGS
;
1116 if (reg
== NULL_RTX
)
1117 pressure_class
= GENERAL_REGS
;
1120 pressure_class
= reg_allocno_class (REGNO (reg
));
1121 pressure_class
= ira_pressure_class_translate
[pressure_class
];
1124 = ira_reg_class_max_nregs
[pressure_class
][GET_MODE (SET_SRC (set
))];
1126 return pressure_class
;
1129 /* Calculates cost and number of registers needed for moving invariant INV
1130 out of the loop and stores them to *COST and *REGS_NEEDED. *CL will be
1131 the REG_CLASS of INV. Return
1132 -1: if INV is invalid.
1133 0: if INV and its depends_on have same reg_class
1134 1: if INV and its depends_on have different reg_classes. */
1137 get_inv_cost (struct invariant
*inv
, int *comp_cost
, unsigned *regs_needed
,
1141 unsigned aregs_needed
[N_REG_CLASSES
];
1143 struct invariant
*dep
;
1147 /* Find the representative of the class of the equivalent invariants. */
1148 inv
= invariants
[inv
->eqto
];
1151 if (! flag_ira_loop_pressure
)
1155 for (i
= 0; i
< ira_pressure_classes_num
; i
++)
1156 regs_needed
[ira_pressure_classes
[i
]] = 0;
1160 || inv
->stamp
== actual_stamp
)
1162 inv
->stamp
= actual_stamp
;
1164 if (! flag_ira_loop_pressure
)
1169 enum reg_class pressure_class
;
1171 pressure_class
= get_pressure_class_and_nregs (inv
->insn
, &nregs
);
1172 regs_needed
[pressure_class
] += nregs
;
1173 *cl
= pressure_class
;
1177 if (!inv
->cheap_address
1178 || inv
->def
->n_addr_uses
< inv
->def
->n_uses
)
1179 (*comp_cost
) += inv
->cost
* inv
->eqno
;
1183 /* Hoisting constant pool constants into stack regs may cost more than
1184 just single register. On x87, the balance is affected both by the
1185 small number of FP registers, and by its register stack organization,
1186 that forces us to add compensation code in and around the loop to
1187 shuffle the operands to the top of stack before use, and pop them
1188 from the stack after the loop finishes.
1190 To model this effect, we increase the number of registers needed for
1191 stack registers by two: one register push, and one register pop.
1192 This usually has the effect that FP constant loads from the constant
1193 pool are not moved out of the loop.
1195 Note that this also means that dependent invariants can not be moved.
1196 However, the primary purpose of this pass is to move loop invariant
1197 address arithmetic out of loops, and address arithmetic that depends
1198 on floating point constants is unlikely to ever occur. */
1199 rtx set
= single_set (inv
->insn
);
1201 && IS_STACK_MODE (GET_MODE (SET_SRC (set
)))
1202 && constant_pool_constant_p (SET_SRC (set
)))
1204 if (flag_ira_loop_pressure
)
1205 regs_needed
[ira_stack_reg_pressure_class
] += 2;
1207 regs_needed
[0] += 2;
1212 EXECUTE_IF_SET_IN_BITMAP (inv
->depends_on
, 0, depno
, bi
)
1215 enum reg_class dep_cl
= ALL_REGS
;
1218 dep
= invariants
[depno
];
1220 /* If DEP is moved out of the loop, it is not a depends_on any more. */
1224 dep_ret
= get_inv_cost (dep
, &acomp_cost
, aregs_needed
, &dep_cl
);
1226 if (! flag_ira_loop_pressure
)
1227 check_p
= aregs_needed
[0] != 0;
1230 for (i
= 0; i
< ira_pressure_classes_num
; i
++)
1231 if (aregs_needed
[ira_pressure_classes
[i
]] != 0)
1233 check_p
= i
< ira_pressure_classes_num
;
1235 if ((dep_ret
== 1) || ((dep_ret
== 0) && (*cl
!= dep_cl
)))
1242 /* We need to check always_executed, since if the original value of
1243 the invariant may be preserved, we may need to keep it in a
1244 separate register. TODO check whether the register has an
1245 use outside of the loop. */
1246 && dep
->always_executed
1247 && !dep
->def
->uses
->next
)
1249 /* If this is a single use, after moving the dependency we will not
1250 need a new register. */
1251 if (! flag_ira_loop_pressure
)
1256 enum reg_class pressure_class
;
1258 pressure_class
= get_pressure_class_and_nregs (inv
->insn
, &nregs
);
1259 aregs_needed
[pressure_class
] -= nregs
;
1263 if (! flag_ira_loop_pressure
)
1264 regs_needed
[0] += aregs_needed
[0];
1267 for (i
= 0; i
< ira_pressure_classes_num
; i
++)
1268 regs_needed
[ira_pressure_classes
[i
]]
1269 += aregs_needed
[ira_pressure_classes
[i
]];
1271 (*comp_cost
) += acomp_cost
;
1276 /* Calculates gain for eliminating invariant INV. REGS_USED is the number
1277 of registers used in the loop, NEW_REGS is the number of new variables
1278 already added due to the invariant motion. The number of registers needed
1279 for it is stored in *REGS_NEEDED. SPEED and CALL_P are flags passed
1280 through to estimate_reg_pressure_cost. */
1283 gain_for_invariant (struct invariant
*inv
, unsigned *regs_needed
,
1284 unsigned *new_regs
, unsigned regs_used
,
1285 bool speed
, bool call_p
)
1287 int comp_cost
, size_cost
;
1288 /* Workaround -Wmaybe-uninitialized false positive during
1289 profiledbootstrap by initializing it. */
1290 enum reg_class cl
= NO_REGS
;
1295 ret
= get_inv_cost (inv
, &comp_cost
, regs_needed
, &cl
);
1297 if (! flag_ira_loop_pressure
)
1299 size_cost
= (estimate_reg_pressure_cost (new_regs
[0] + regs_needed
[0],
1300 regs_used
, speed
, call_p
)
1301 - estimate_reg_pressure_cost (new_regs
[0],
1302 regs_used
, speed
, call_p
));
1306 else if ((ret
== 0) && (cl
== NO_REGS
))
1307 /* Hoist it anyway since it does not impact register pressure. */
1312 enum reg_class pressure_class
;
1314 for (i
= 0; i
< ira_pressure_classes_num
; i
++)
1316 pressure_class
= ira_pressure_classes
[i
];
1318 if (!reg_classes_intersect_p (pressure_class
, cl
))
1321 if ((int) new_regs
[pressure_class
]
1322 + (int) regs_needed
[pressure_class
]
1323 + LOOP_DATA (curr_loop
)->max_reg_pressure
[pressure_class
]
1324 + IRA_LOOP_RESERVED_REGS
1325 > ira_class_hard_regs_num
[pressure_class
])
1328 if (i
< ira_pressure_classes_num
)
1329 /* There will be register pressure excess and we want not to
1330 make this loop invariant motion. All loop invariants with
1331 non-positive gains will be rejected in function
1332 find_invariants_to_move. Therefore we return the negative
1335 One could think that this rejects also expensive loop
1336 invariant motions and this will hurt code performance.
1337 However numerous experiments with different heuristics
1338 taking invariant cost into account did not confirm this
1339 assumption. There are possible explanations for this
1341 o probably all expensive invariants were already moved out
1342 of the loop by PRE and gimple invariant motion pass.
1343 o expensive invariant execution will be hidden by insn
1344 scheduling or OOO processor hardware because usually such
1345 invariants have a lot of freedom to be executed
1347 Another reason for ignoring invariant cost vs spilling cost
1348 heuristics is also in difficulties to evaluate accurately
1349 spill cost at this stage. */
1355 return comp_cost
- size_cost
;
1358 /* Finds invariant with best gain for moving. Returns the gain, stores
1359 the invariant in *BEST and number of registers needed for it to
1360 *REGS_NEEDED. REGS_USED is the number of registers used in the loop.
1361 NEW_REGS is the number of new variables already added due to invariant
1365 best_gain_for_invariant (struct invariant
**best
, unsigned *regs_needed
,
1366 unsigned *new_regs
, unsigned regs_used
,
1367 bool speed
, bool call_p
)
1369 struct invariant
*inv
;
1370 int i
, gain
= 0, again
;
1371 unsigned aregs_needed
[N_REG_CLASSES
], invno
;
1373 FOR_EACH_VEC_ELT (invariants
, invno
, inv
)
1378 /* Only consider the "representatives" of equivalent invariants. */
1379 if (inv
->eqto
!= inv
->invno
)
1382 again
= gain_for_invariant (inv
, aregs_needed
, new_regs
, regs_used
,
1388 if (! flag_ira_loop_pressure
)
1389 regs_needed
[0] = aregs_needed
[0];
1392 for (i
= 0; i
< ira_pressure_classes_num
; i
++)
1393 regs_needed
[ira_pressure_classes
[i
]]
1394 = aregs_needed
[ira_pressure_classes
[i
]];
1402 /* Marks invariant INVNO and all its dependencies for moving. */
1405 set_move_mark (unsigned invno
, int gain
)
1407 struct invariant
*inv
= invariants
[invno
];
1410 /* Find the representative of the class of the equivalent invariants. */
1411 inv
= invariants
[inv
->eqto
];
1420 fprintf (dump_file
, "Decided to move invariant %d -- gain %d\n",
1423 fprintf (dump_file
, "Decided to move dependent invariant %d\n",
1427 EXECUTE_IF_SET_IN_BITMAP (inv
->depends_on
, 0, invno
, bi
)
1429 set_move_mark (invno
, -1);
1433 /* Determines which invariants to move. */
1436 find_invariants_to_move (bool speed
, bool call_p
)
1439 unsigned i
, regs_used
, regs_needed
[N_REG_CLASSES
], new_regs
[N_REG_CLASSES
];
1440 struct invariant
*inv
= NULL
;
1442 if (!invariants
.length ())
1445 if (flag_ira_loop_pressure
)
1446 /* REGS_USED is actually never used when the flag is on. */
1449 /* We do not really do a good job in estimating number of
1450 registers used; we put some initial bound here to stand for
1451 induction variables etc. that we do not detect. */
1453 unsigned int n_regs
= DF_REG_SIZE (df
);
1457 for (i
= 0; i
< n_regs
; i
++)
1459 if (!DF_REGNO_FIRST_DEF (i
) && DF_REGNO_LAST_USE (i
))
1461 /* This is a value that is used but not changed inside loop. */
1467 if (! flag_ira_loop_pressure
)
1468 new_regs
[0] = regs_needed
[0] = 0;
1471 for (i
= 0; (int) i
< ira_pressure_classes_num
; i
++)
1472 new_regs
[ira_pressure_classes
[i
]] = 0;
1474 while ((gain
= best_gain_for_invariant (&inv
, regs_needed
,
1475 new_regs
, regs_used
,
1476 speed
, call_p
)) > 0)
1478 set_move_mark (inv
->invno
, gain
);
1479 if (! flag_ira_loop_pressure
)
1480 new_regs
[0] += regs_needed
[0];
1483 for (i
= 0; (int) i
< ira_pressure_classes_num
; i
++)
1484 new_regs
[ira_pressure_classes
[i
]]
1485 += regs_needed
[ira_pressure_classes
[i
]];
1490 /* Replace the uses, reached by the definition of invariant INV, by REG.
1492 IN_GROUP is nonzero if this is part of a group of changes that must be
1493 performed as a group. In that case, the changes will be stored. The
1494 function `apply_change_group' will validate and apply the changes. */
1497 replace_uses (struct invariant
*inv
, rtx reg
, bool in_group
)
1499 /* Replace the uses we know to be dominated. It saves work for copy
1500 propagation, and also it is necessary so that dependent invariants
1501 are computed right. */
1505 for (use
= inv
->def
->uses
; use
; use
= use
->next
)
1506 validate_change (use
->insn
, use
->pos
, reg
, true);
1508 /* If we aren't part of a larger group, apply the changes now. */
1510 return apply_change_group ();
1516 /* Move invariant INVNO out of the LOOP. Returns true if this succeeds, false
1520 move_invariant_reg (struct loop
*loop
, unsigned invno
)
1522 struct invariant
*inv
= invariants
[invno
];
1523 struct invariant
*repr
= invariants
[inv
->eqto
];
1525 basic_block preheader
= loop_preheader_edge (loop
)->src
;
1526 rtx reg
, set
, dest
, note
;
1535 /* If this is a representative of the class of equivalent invariants,
1536 really move the invariant. Otherwise just replace its use with
1537 the register used for the representative. */
1540 if (inv
->depends_on
)
1542 EXECUTE_IF_SET_IN_BITMAP (inv
->depends_on
, 0, i
, bi
)
1544 if (!move_invariant_reg (loop
, i
))
1549 /* Move the set out of the loop. If the set is always executed (we could
1550 omit this condition if we know that the register is unused outside of
1551 the loop, but it does not seem worth finding out) and it has no uses
1552 that would not be dominated by it, we may just move it (TODO).
1553 Otherwise we need to create a temporary register. */
1554 set
= single_set (inv
->insn
);
1555 reg
= dest
= SET_DEST (set
);
1556 if (GET_CODE (reg
) == SUBREG
)
1557 reg
= SUBREG_REG (reg
);
1559 regno
= REGNO (reg
);
1561 reg
= gen_reg_rtx_and_attrs (dest
);
1563 /* Try replacing the destination by a new pseudoregister. */
1564 validate_change (inv
->insn
, &SET_DEST (set
), reg
, true);
1566 /* As well as all the dominated uses. */
1567 replace_uses (inv
, reg
, true);
1569 /* And validate all the changes. */
1570 if (!apply_change_group ())
1573 emit_insn_after (gen_move_insn (dest
, reg
), inv
->insn
);
1574 reorder_insns (inv
->insn
, inv
->insn
, BB_END (preheader
));
1576 /* If there is a REG_EQUAL note on the insn we just moved, and the
1577 insn is in a basic block that is not always executed or the note
1578 contains something for which we don't know the invariant status,
1579 the note may no longer be valid after we move the insn. Note that
1580 uses in REG_EQUAL notes are taken into account in the computation
1581 of invariants, so it is safe to retain the note even if it contains
1582 register references for which we know the invariant status. */
1583 if ((note
= find_reg_note (inv
->insn
, REG_EQUAL
, NULL_RTX
))
1584 && (!inv
->always_executed
1585 || !check_maybe_invariant (XEXP (note
, 0))))
1586 remove_note (inv
->insn
, note
);
1590 if (!move_invariant_reg (loop
, repr
->invno
))
1593 regno
= repr
->orig_regno
;
1594 if (!replace_uses (inv
, reg
, false))
1596 set
= single_set (inv
->insn
);
1597 emit_insn_after (gen_move_insn (SET_DEST (set
), reg
), inv
->insn
);
1598 delete_insn (inv
->insn
);
1602 inv
->orig_regno
= regno
;
1607 /* If we failed, clear move flag, so that we do not try to move inv
1610 fprintf (dump_file
, "Failed to move invariant %d\n", invno
);
1612 inv
->reg
= NULL_RTX
;
1613 inv
->orig_regno
= -1;
1618 /* Move selected invariant out of the LOOP. Newly created regs are marked
1619 in TEMPORARY_REGS. */
1622 move_invariants (struct loop
*loop
)
1624 struct invariant
*inv
;
1627 FOR_EACH_VEC_ELT (invariants
, i
, inv
)
1628 move_invariant_reg (loop
, i
);
1629 if (flag_ira_loop_pressure
&& resize_reg_info ())
1631 FOR_EACH_VEC_ELT (invariants
, i
, inv
)
1632 if (inv
->reg
!= NULL_RTX
)
1634 if (inv
->orig_regno
>= 0)
1635 setup_reg_classes (REGNO (inv
->reg
),
1636 reg_preferred_class (inv
->orig_regno
),
1637 reg_alternate_class (inv
->orig_regno
),
1638 reg_allocno_class (inv
->orig_regno
));
1640 setup_reg_classes (REGNO (inv
->reg
),
1641 GENERAL_REGS
, NO_REGS
, GENERAL_REGS
);
1646 /* Initializes invariant motion data. */
1649 init_inv_motion_data (void)
1653 invariants
.create (100);
1656 /* Frees the data allocated by invariant motion. */
1659 free_inv_motion_data (void)
1663 struct invariant
*inv
;
1665 check_invariant_table_size ();
1666 for (i
= 0; i
< DF_DEFS_TABLE_SIZE (); i
++)
1668 inv
= invariant_table
[i
];
1672 gcc_assert (def
!= NULL
);
1674 free_use_list (def
->uses
);
1676 invariant_table
[i
] = NULL
;
1680 FOR_EACH_VEC_ELT (invariants
, i
, inv
)
1682 BITMAP_FREE (inv
->depends_on
);
1685 invariants
.release ();
1688 /* Move the invariants out of the LOOP. */
1691 move_single_loop_invariants (struct loop
*loop
)
1693 init_inv_motion_data ();
1695 find_invariants (loop
);
1696 find_invariants_to_move (optimize_loop_for_speed_p (loop
),
1697 LOOP_DATA (loop
)->has_call
);
1698 move_invariants (loop
);
1700 free_inv_motion_data ();
1703 /* Releases the auxiliary data for LOOP. */
1706 free_loop_data (struct loop
*loop
)
1708 struct loop_data
*data
= LOOP_DATA (loop
);
1712 bitmap_clear (&LOOP_DATA (loop
)->regs_ref
);
1713 bitmap_clear (&LOOP_DATA (loop
)->regs_live
);
1720 /* Registers currently living. */
1721 static bitmap_head curr_regs_live
;
1723 /* Current reg pressure for each pressure class. */
1724 static int curr_reg_pressure
[N_REG_CLASSES
];
1726 /* Record all regs that are set in any one insn. Communication from
1727 mark_reg_{store,clobber} and global_conflicts. Asm can refer to
1728 all hard-registers. */
1729 static rtx regs_set
[(FIRST_PSEUDO_REGISTER
> MAX_RECOG_OPERANDS
1730 ? FIRST_PSEUDO_REGISTER
: MAX_RECOG_OPERANDS
) * 2];
1731 /* Number of regs stored in the previous array. */
1732 static int n_regs_set
;
1734 /* Return pressure class and number of needed hard registers (through
1735 *NREGS) of register REGNO. */
1736 static enum reg_class
1737 get_regno_pressure_class (int regno
, int *nregs
)
1739 if (regno
>= FIRST_PSEUDO_REGISTER
)
1741 enum reg_class pressure_class
;
1743 pressure_class
= reg_allocno_class (regno
);
1744 pressure_class
= ira_pressure_class_translate
[pressure_class
];
1746 = ira_reg_class_max_nregs
[pressure_class
][PSEUDO_REGNO_MODE (regno
)];
1747 return pressure_class
;
1749 else if (! TEST_HARD_REG_BIT (ira_no_alloc_regs
, regno
)
1750 && ! TEST_HARD_REG_BIT (eliminable_regset
, regno
))
1753 return ira_pressure_class_translate
[REGNO_REG_CLASS (regno
)];
1762 /* Increase (if INCR_P) or decrease current register pressure for
1765 change_pressure (int regno
, bool incr_p
)
1768 enum reg_class pressure_class
;
1770 pressure_class
= get_regno_pressure_class (regno
, &nregs
);
1772 curr_reg_pressure
[pressure_class
] -= nregs
;
1775 curr_reg_pressure
[pressure_class
] += nregs
;
1776 if (LOOP_DATA (curr_loop
)->max_reg_pressure
[pressure_class
]
1777 < curr_reg_pressure
[pressure_class
])
1778 LOOP_DATA (curr_loop
)->max_reg_pressure
[pressure_class
]
1779 = curr_reg_pressure
[pressure_class
];
1783 /* Mark REGNO birth. */
1785 mark_regno_live (int regno
)
1789 for (loop
= curr_loop
;
1790 loop
!= current_loops
->tree_root
;
1791 loop
= loop_outer (loop
))
1792 bitmap_set_bit (&LOOP_DATA (loop
)->regs_live
, regno
);
1793 if (!bitmap_set_bit (&curr_regs_live
, regno
))
1795 change_pressure (regno
, true);
1798 /* Mark REGNO death. */
1800 mark_regno_death (int regno
)
1802 if (! bitmap_clear_bit (&curr_regs_live
, regno
))
1804 change_pressure (regno
, false);
1807 /* Mark setting register REG. */
1809 mark_reg_store (rtx reg
, const_rtx setter ATTRIBUTE_UNUSED
,
1810 void *data ATTRIBUTE_UNUSED
)
1814 if (GET_CODE (reg
) == SUBREG
)
1815 reg
= SUBREG_REG (reg
);
1820 regs_set
[n_regs_set
++] = reg
;
1822 regno
= REGNO (reg
);
1824 if (regno
>= FIRST_PSEUDO_REGISTER
)
1825 mark_regno_live (regno
);
1828 int last
= regno
+ hard_regno_nregs
[regno
][GET_MODE (reg
)];
1830 while (regno
< last
)
1832 mark_regno_live (regno
);
1838 /* Mark clobbering register REG. */
1840 mark_reg_clobber (rtx reg
, const_rtx setter
, void *data
)
1842 if (GET_CODE (setter
) == CLOBBER
)
1843 mark_reg_store (reg
, setter
, data
);
1846 /* Mark register REG death. */
1848 mark_reg_death (rtx reg
)
1850 int regno
= REGNO (reg
);
1852 if (regno
>= FIRST_PSEUDO_REGISTER
)
1853 mark_regno_death (regno
);
1856 int last
= regno
+ hard_regno_nregs
[regno
][GET_MODE (reg
)];
1858 while (regno
< last
)
1860 mark_regno_death (regno
);
1866 /* Mark occurrence of registers in X for the current loop. */
1868 mark_ref_regs (rtx x
)
1877 code
= GET_CODE (x
);
1882 for (loop
= curr_loop
;
1883 loop
!= current_loops
->tree_root
;
1884 loop
= loop_outer (loop
))
1885 bitmap_set_bit (&LOOP_DATA (loop
)->regs_ref
, REGNO (x
));
1889 fmt
= GET_RTX_FORMAT (code
);
1890 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
1892 mark_ref_regs (XEXP (x
, i
));
1893 else if (fmt
[i
] == 'E')
1897 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
1898 mark_ref_regs (XVECEXP (x
, i
, j
));
1902 /* Calculate register pressure in the loops. */
1904 calculate_loop_reg_pressure (void)
1912 struct loop
*loop
, *parent
;
1914 FOR_EACH_LOOP (loop
, 0)
1915 if (loop
->aux
== NULL
)
1917 loop
->aux
= xcalloc (1, sizeof (struct loop_data
));
1918 bitmap_initialize (&LOOP_DATA (loop
)->regs_ref
, ®_obstack
);
1919 bitmap_initialize (&LOOP_DATA (loop
)->regs_live
, ®_obstack
);
1921 ira_setup_eliminable_regset ();
1922 bitmap_initialize (&curr_regs_live
, ®_obstack
);
1923 FOR_EACH_BB_FN (bb
, cfun
)
1925 curr_loop
= bb
->loop_father
;
1926 if (curr_loop
== current_loops
->tree_root
)
1929 for (loop
= curr_loop
;
1930 loop
!= current_loops
->tree_root
;
1931 loop
= loop_outer (loop
))
1932 bitmap_ior_into (&LOOP_DATA (loop
)->regs_live
, DF_LR_IN (bb
));
1934 bitmap_copy (&curr_regs_live
, DF_LR_IN (bb
));
1935 for (i
= 0; i
< ira_pressure_classes_num
; i
++)
1936 curr_reg_pressure
[ira_pressure_classes
[i
]] = 0;
1937 EXECUTE_IF_SET_IN_BITMAP (&curr_regs_live
, 0, j
, bi
)
1938 change_pressure (j
, true);
1940 FOR_BB_INSNS (bb
, insn
)
1942 if (! NONDEBUG_INSN_P (insn
))
1945 mark_ref_regs (PATTERN (insn
));
1947 note_stores (PATTERN (insn
), mark_reg_clobber
, NULL
);
1949 /* Mark any registers dead after INSN as dead now. */
1951 for (link
= REG_NOTES (insn
); link
; link
= XEXP (link
, 1))
1952 if (REG_NOTE_KIND (link
) == REG_DEAD
)
1953 mark_reg_death (XEXP (link
, 0));
1955 /* Mark any registers set in INSN as live,
1956 and mark them as conflicting with all other live regs.
1957 Clobbers are processed again, so they conflict with
1958 the registers that are set. */
1960 note_stores (PATTERN (insn
), mark_reg_store
, NULL
);
1963 for (link
= REG_NOTES (insn
); link
; link
= XEXP (link
, 1))
1964 if (REG_NOTE_KIND (link
) == REG_INC
)
1965 mark_reg_store (XEXP (link
, 0), NULL_RTX
, NULL
);
1967 while (n_regs_set
-- > 0)
1969 rtx note
= find_regno_note (insn
, REG_UNUSED
,
1970 REGNO (regs_set
[n_regs_set
]));
1974 mark_reg_death (XEXP (note
, 0));
1978 bitmap_clear (&curr_regs_live
);
1979 if (flag_ira_region
== IRA_REGION_MIXED
1980 || flag_ira_region
== IRA_REGION_ALL
)
1981 FOR_EACH_LOOP (loop
, 0)
1983 EXECUTE_IF_SET_IN_BITMAP (&LOOP_DATA (loop
)->regs_live
, 0, j
, bi
)
1984 if (! bitmap_bit_p (&LOOP_DATA (loop
)->regs_ref
, j
))
1986 enum reg_class pressure_class
;
1989 pressure_class
= get_regno_pressure_class (j
, &nregs
);
1990 LOOP_DATA (loop
)->max_reg_pressure
[pressure_class
] -= nregs
;
1993 if (dump_file
== NULL
)
1995 FOR_EACH_LOOP (loop
, 0)
1997 parent
= loop_outer (loop
);
1998 fprintf (dump_file
, "\n Loop %d (parent %d, header bb%d, depth %d)\n",
1999 loop
->num
, (parent
== NULL
? -1 : parent
->num
),
2000 loop
->header
->index
, loop_depth (loop
));
2001 fprintf (dump_file
, "\n ref. regnos:");
2002 EXECUTE_IF_SET_IN_BITMAP (&LOOP_DATA (loop
)->regs_ref
, 0, j
, bi
)
2003 fprintf (dump_file
, " %d", j
);
2004 fprintf (dump_file
, "\n live regnos:");
2005 EXECUTE_IF_SET_IN_BITMAP (&LOOP_DATA (loop
)->regs_live
, 0, j
, bi
)
2006 fprintf (dump_file
, " %d", j
);
2007 fprintf (dump_file
, "\n Pressure:");
2008 for (i
= 0; (int) i
< ira_pressure_classes_num
; i
++)
2010 enum reg_class pressure_class
;
2012 pressure_class
= ira_pressure_classes
[i
];
2013 if (LOOP_DATA (loop
)->max_reg_pressure
[pressure_class
] == 0)
2015 fprintf (dump_file
, " %s=%d", reg_class_names
[pressure_class
],
2016 LOOP_DATA (loop
)->max_reg_pressure
[pressure_class
]);
2018 fprintf (dump_file
, "\n");
2024 /* Move the invariants out of the loops. */
2027 move_loop_invariants (void)
2031 if (flag_ira_loop_pressure
)
2034 regstat_init_n_sets_and_refs ();
2035 ira_set_pseudo_classes (true, dump_file
);
2036 calculate_loop_reg_pressure ();
2037 regstat_free_n_sets_and_refs ();
2039 df_set_flags (DF_EQ_NOTES
+ DF_DEFER_INSN_RESCAN
);
2040 /* Process the loops, innermost first. */
2041 FOR_EACH_LOOP (loop
, LI_FROM_INNERMOST
)
2044 /* move_single_loop_invariants for very large loops
2045 is time consuming and might need a lot of memory. */
2046 if (loop
->num_nodes
<= (unsigned) LOOP_INVARIANT_MAX_BBS_IN_LOOP
)
2047 move_single_loop_invariants (loop
);
2050 FOR_EACH_LOOP (loop
, 0)
2052 free_loop_data (loop
);
2055 if (flag_ira_loop_pressure
)
2056 /* There is no sense to keep this info because it was most
2057 probably outdated by subsequent passes. */
2059 free (invariant_table
);
2060 invariant_table
= NULL
;
2061 invariant_table_size
= 0;
2063 #ifdef ENABLE_CHECKING
2064 verify_flow_info ();