/* Move registers around to reduce number of move instructions needed.
- Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
- 1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
+ Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997,
+ 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
+ Free Software Foundation, Inc.
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
-Software Foundation; either version 2, or (at your option) any later
+Software Foundation; either version 3, or (at your option) any later
version.
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
for more details.
You should have received a copy of the GNU General Public License
-along with GCC; see the file COPYING. If not, write to the Free
-Software Foundation, 59 Temple Place - Suite 330, Boston, MA
-02111-1307, USA. */
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
-/* This module looks for cases where matching constraints would force
- an instruction to need a reload, and this reload would be a register
- to register move. It then attempts to change the registers used by the
- instruction to avoid the move instruction. */
+/* This module makes some simple RTL code transformations which
+ improve the subsequent register allocation. */
#include "config.h"
#include "system.h"
#include "except.h"
#include "toplev.h"
#include "reload.h"
+#include "timevar.h"
+#include "tree-pass.h"
+#include "df.h"
-
-/* Turn STACK_GROWS_DOWNWARD into a boolean. */
-#ifdef STACK_GROWS_DOWNWARD
-#undef STACK_GROWS_DOWNWARD
-#define STACK_GROWS_DOWNWARD 1
-#else
-#define STACK_GROWS_DOWNWARD 0
-#endif
-
-static int perhaps_ends_bb_p (rtx);
static int optimize_reg_copy_1 (rtx, rtx, rtx);
static void optimize_reg_copy_2 (rtx, rtx, rtx);
static void optimize_reg_copy_3 (rtx, rtx, rtx);
-static void copy_src_to_dest (rtx, rtx, rtx, int);
-static int *regmove_bb_head;
+static void copy_src_to_dest (rtx, rtx, rtx);
struct match {
int with[MAX_RECOG_OPERANDS];
int early_clobber[MAX_RECOG_OPERANDS];
};
-static rtx discover_flags_reg (void);
-static void mark_flags_life_zones (rtx);
-static void flags_set_1 (rtx, rtx, void *);
-
-static int try_auto_increment (rtx, rtx, rtx, rtx, HOST_WIDE_INT, int);
static int find_matches (rtx, struct match *);
-static void replace_in_call_usage (rtx *, unsigned int, rtx, rtx);
-static int fixup_match_1 (rtx, rtx, rtx, rtx, rtx, int, int, int, FILE *);
-static int reg_is_remote_constant_p (rtx, rtx, rtx);
-static int stable_and_no_regs_but_for_p (rtx, rtx, rtx);
static int regclass_compatible_p (int, int);
-static int replacement_quality (rtx);
-static int fixup_match_2 (rtx, rtx, rtx, rtx, FILE *);
+static int fixup_match_2 (rtx, rtx, rtx, rtx);
/* Return nonzero if registers with CLASS1 and CLASS2 can be merged without
causing too much register allocation problems. */
&& ! CLASS_LIKELY_SPILLED_P (class1)));
}
+\f
+#ifdef AUTO_INC_DEC
+
+/* Find the place in the rtx X where REG is used as a memory address.
+ Return the MEM rtx that so uses it.
+ If PLUSCONST is nonzero, search instead for a memory address equivalent to
+ (plus REG (const_int PLUSCONST)).
+
+ If such an address does not appear, return 0.
+ If REG appears more than once, or is used other than in such an address,
+ return (rtx) 1. */
+
+static rtx
+find_use_as_address (rtx x, rtx reg, HOST_WIDE_INT plusconst)
+{
+ enum rtx_code code = GET_CODE (x);
+ const char * const fmt = GET_RTX_FORMAT (code);
+ int i;
+ rtx value = 0;
+ rtx tem;
+
+ if (code == MEM && XEXP (x, 0) == reg && plusconst == 0)
+ return x;
+
+ if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS
+ && XEXP (XEXP (x, 0), 0) == reg
+ && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
+ && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst)
+ return x;
+
+ if (code == SIGN_EXTRACT || code == ZERO_EXTRACT)
+ {
+ /* If REG occurs inside a MEM used in a bit-field reference,
+ that is unacceptable. */
+ if (find_use_as_address (XEXP (x, 0), reg, 0) != 0)
+ return (rtx) (size_t) 1;
+ }
+
+ if (x == reg)
+ return (rtx) (size_t) 1;
+
+ for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
+ {
+ if (fmt[i] == 'e')
+ {
+ tem = find_use_as_address (XEXP (x, i), reg, plusconst);
+ if (value == 0)
+ value = tem;
+ else if (tem != 0)
+ return (rtx) (size_t) 1;
+ }
+ else if (fmt[i] == 'E')
+ {
+ int j;
+ for (j = XVECLEN (x, i) - 1; j >= 0; j--)
+ {
+ tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst);
+ if (value == 0)
+ value = tem;
+ else if (tem != 0)
+ return (rtx) (size_t) 1;
+ }
+ }
+ }
+
+ return value;
+}
+
+
/* INC_INSN is an instruction that adds INCREMENT to REG.
Try to fold INC_INSN as a post/pre in/decrement into INSN.
Iff INC_INSN_SET is nonzero, inc_insn has a destination different from src.
/* If there is a REG_DEAD note on this insn, we must
change this not to REG_UNUSED meaning that the register
is set, but the value is dead. Failure to do so will
- result in a sched1 abort -- when it recomputes lifetime
+ result in sched1 dying -- when it recomputes lifetime
information, the number of REG_DEAD notes will have
changed. */
rtx note = find_reg_note (insn, REG_DEAD, reg);
if (note)
PUT_MODE (note, REG_UNUSED);
- REG_NOTES (insn)
- = gen_rtx_EXPR_LIST (REG_INC,
- reg, REG_NOTES (insn));
+ add_reg_note (insn, REG_INC, reg);
+
if (! inc_insn_set)
delete_insn (inc_insn);
return 1;
}
return 0;
}
-\f
-/* Determine if the pattern generated by add_optab has a clobber,
- such as might be issued for a flags hard register. To make the
- code elsewhere simpler, we handle cc0 in this same framework.
-
- Return the register if one was discovered. Return NULL_RTX if
- if no flags were found. Return pc_rtx if we got confused. */
-
-static rtx
-discover_flags_reg (void)
-{
- rtx tmp;
- tmp = gen_rtx_REG (word_mode, 10000);
- tmp = gen_add3_insn (tmp, tmp, GEN_INT (2));
-
- /* If we get something that isn't a simple set, or a
- [(set ..) (clobber ..)], this whole function will go wrong. */
- if (GET_CODE (tmp) == SET)
- return NULL_RTX;
- else if (GET_CODE (tmp) == PARALLEL)
- {
- int found;
-
- if (XVECLEN (tmp, 0) != 2)
- return pc_rtx;
- tmp = XVECEXP (tmp, 0, 1);
- if (GET_CODE (tmp) != CLOBBER)
- return pc_rtx;
- tmp = XEXP (tmp, 0);
-
- /* Don't do anything foolish if the md wanted to clobber a
- scratch or something. We only care about hard regs.
- Moreover we don't like the notion of subregs of hard regs. */
- if (GET_CODE (tmp) == SUBREG
- && GET_CODE (SUBREG_REG (tmp)) == REG
- && REGNO (SUBREG_REG (tmp)) < FIRST_PSEUDO_REGISTER)
- return pc_rtx;
- found = (GET_CODE (tmp) == REG && REGNO (tmp) < FIRST_PSEUDO_REGISTER);
-
- return (found ? tmp : NULL_RTX);
- }
-
- return pc_rtx;
-}
-
-/* It is a tedious task identifying when the flags register is live and
- when it is safe to optimize. Since we process the instruction stream
- multiple times, locate and record these live zones by marking the
- mode of the instructions --
-
- QImode is used on the instruction at which the flags becomes live.
-
- HImode is used within the range (exclusive) that the flags are
- live. Thus the user of the flags is not marked.
-
- All other instructions are cleared to VOIDmode. */
-
-/* Used to communicate with flags_set_1. */
-static rtx flags_set_1_rtx;
-static int flags_set_1_set;
-
-static void
-mark_flags_life_zones (rtx flags)
-{
- int flags_regno;
- int flags_nregs;
- basic_block block;
-
-#ifdef HAVE_cc0
- /* If we found a flags register on a cc0 host, bail. */
- if (flags == NULL_RTX)
- flags = cc0_rtx;
- else if (flags != cc0_rtx)
- flags = pc_rtx;
-#endif
-
- /* Simple cases first: if no flags, clear all modes. If confusing,
- mark the entire function as being in a flags shadow. */
- if (flags == NULL_RTX || flags == pc_rtx)
- {
- enum machine_mode mode = (flags ? HImode : VOIDmode);
- rtx insn;
- for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
- PUT_MODE (insn, mode);
- return;
- }
-
-#ifdef HAVE_cc0
- flags_regno = -1;
- flags_nregs = 1;
-#else
- flags_regno = REGNO (flags);
- flags_nregs = HARD_REGNO_NREGS (flags_regno, GET_MODE (flags));
#endif
- flags_set_1_rtx = flags;
- /* Process each basic block. */
- FOR_EACH_BB_REVERSE (block)
- {
- rtx insn, end;
- int live;
-
- insn = block->head;
- end = block->end;
-
- /* Look out for the (unlikely) case of flags being live across
- basic block boundaries. */
- live = 0;
-#ifndef HAVE_cc0
- {
- int i;
- for (i = 0; i < flags_nregs; ++i)
- live |= REGNO_REG_SET_P (block->global_live_at_start,
- flags_regno + i);
- }
-#endif
-
- while (1)
- {
- /* Process liveness in reverse order of importance --
- alive, death, birth. This lets more important info
- overwrite the mode of lesser info. */
-
- if (INSN_P (insn))
- {
-#ifdef HAVE_cc0
- /* In the cc0 case, death is not marked in reg notes,
- but is instead the mere use of cc0 when it is alive. */
- if (live && reg_mentioned_p (cc0_rtx, PATTERN (insn)))
- live = 0;
-#else
- /* In the hard reg case, we watch death notes. */
- if (live && find_regno_note (insn, REG_DEAD, flags_regno))
- live = 0;
-#endif
- PUT_MODE (insn, (live ? HImode : VOIDmode));
-
- /* In either case, birth is denoted simply by it's presence
- as the destination of a set. */
- flags_set_1_set = 0;
- note_stores (PATTERN (insn), flags_set_1, NULL);
- if (flags_set_1_set)
- {
- live = 1;
- PUT_MODE (insn, QImode);
- }
- }
- else
- PUT_MODE (insn, (live ? HImode : VOIDmode));
-
- if (insn == end)
- break;
- insn = NEXT_INSN (insn);
- }
- }
-}
-
-/* A subroutine of mark_flags_life_zones, called through note_stores. */
-
-static void
-flags_set_1 (rtx x, rtx pat, void *data ATTRIBUTE_UNUSED)
-{
- if (GET_CODE (pat) == SET
- && reg_overlap_mentioned_p (x, flags_set_1_rtx))
- flags_set_1_set = 1;
-}
\f
static int *regno_src_regno;
-/* Indicate how good a choice REG (which appears as a source) is to replace
- a destination register with. The higher the returned value, the better
- the choice. The main objective is to avoid using a register that is
- a candidate for tying to a hard register, since the output might in
- turn be a candidate to be tied to a different hard register. */
-static int
-replacement_quality (rtx reg)
-{
- int src_regno;
-
- /* Bad if this isn't a register at all. */
- if (GET_CODE (reg) != REG)
- return 0;
-
- /* If this register is not meant to get a hard register,
- it is a poor choice. */
- if (REG_LIVE_LENGTH (REGNO (reg)) < 0)
- return 0;
-
- src_regno = regno_src_regno[REGNO (reg)];
-
- /* If it was not copied from another register, it is fine. */
- if (src_regno < 0)
- return 3;
-
- /* Copied from a hard register? */
- if (src_regno < FIRST_PSEUDO_REGISTER)
- return 1;
-
- /* Copied from a pseudo register - not as bad as from a hard register,
- yet still cumbersome, since the register live length will be lengthened
- when the registers get tied. */
- return 2;
-}
-\f
-/* Return 1 if INSN might end a basic block. */
-
-static int perhaps_ends_bb_p (rtx insn)
-{
- switch (GET_CODE (insn))
- {
- case CODE_LABEL:
- case JUMP_INSN:
- /* These always end a basic block. */
- return 1;
-
- case CALL_INSN:
- /* A CALL_INSN might be the last insn of a basic block, if it is inside
- an EH region or if there are nonlocal gotos. Note that this test is
- very conservative. */
- if (nonlocal_goto_handler_labels)
- return 1;
- /* FALLTHRU */
- default:
- return can_throw_internal (insn);
- }
-}
-\f
/* INSN is a copy from SRC to DEST, both registers, and SRC does not die
in INSN.
rtx dest_death = 0;
int sregno = REGNO (src);
int dregno = REGNO (dest);
+ basic_block bb = BLOCK_FOR_INSN (insn);
/* We don't want to mess with hard regs if register classes are small. */
if (sregno == dregno
for (p = NEXT_INSN (insn); p; p = NEXT_INSN (p))
{
- /* ??? We can't scan past the end of a basic block without updating
- the register lifetime info (REG_DEAD/basic_block_live_at_start). */
- if (perhaps_ends_bb_p (p))
- break;
- else if (! INSN_P (p))
+ if (! INSN_P (p))
continue;
+ if (BLOCK_FOR_INSN (p) != bb)
+ break;
if (reg_set_p (src, p) || reg_set_p (dest, p)
/* If SRC is an asm-declared register, it must not be replaced
|| (sregno < FIRST_PSEUDO_REGISTER
&& asm_noperands (PATTERN (p)) >= 0
&& reg_overlap_mentioned_p (src, PATTERN (p)))
+ /* Don't change hard registers used by a call. */
+ || (CALL_P (p) && sregno < FIRST_PSEUDO_REGISTER
+ && find_reg_fusage (p, USE, src))
/* Don't change a USE of a register. */
|| (GET_CODE (PATTERN (p)) == USE
&& reg_overlap_mentioned_p (src, XEXP (PATTERN (p), 0))))
int s_length = 0;
int d_n_calls = 0;
int s_n_calls = 0;
+ int s_freq_calls = 0;
+ int d_freq_calls = 0;
/* We can do the optimization. Scan forward from INSN again,
replacing regs as we go. Set FAILED if a replacement can't
if (sregno < FIRST_PSEUDO_REGISTER
&& reg_mentioned_p (dest, PATTERN (q)))
failed = 1;
+
+ /* Attempt to replace all uses. */
+ else if (!validate_replace_rtx (src, dest, q))
+ failed = 1;
- /* Replace all uses and make sure that the register
- isn't still present. */
- else if (validate_replace_rtx (src, dest, q)
- && (sregno >= FIRST_PSEUDO_REGISTER
- || ! reg_overlap_mentioned_p (src,
- PATTERN (q))))
- ;
- else
+ /* If this succeeded, but some part of the register
+ is still present, undo the replacement. */
+ else if (sregno < FIRST_PSEUDO_REGISTER
+ && reg_overlap_mentioned_p (src, PATTERN (q)))
{
validate_replace_rtx (dest, src, q);
failed = 1;
/* If the insn in which SRC dies is a CALL_INSN, don't count it
as a call that has been crossed. Otherwise, count it. */
- if (q != p && GET_CODE (q) == CALL_INSN)
+ if (q != p && CALL_P (q))
{
/* Similarly, total calls for SREGNO, total calls beyond
the death note for DREGNO. */
s_n_calls++;
+ s_freq_calls += REG_FREQ_FROM_BB (BLOCK_FOR_INSN (q));
if (dest_death)
- d_n_calls++;
+ {
+ d_n_calls++;
+ d_freq_calls += REG_FREQ_FROM_BB (BLOCK_FOR_INSN (q));
+ }
}
/* If DEST dies here, remove the death note and save it for
}
REG_N_CALLS_CROSSED (sregno) -= s_n_calls;
+ REG_FREQ_CALLS_CROSSED (sregno) -= s_freq_calls;
}
/* Move death note of SRC from P to INSN. */
if (REG_LIVE_LENGTH (dregno) >= 0)
REG_LIVE_LENGTH (dregno) += d_length;
REG_N_CALLS_CROSSED (dregno) += d_n_calls;
+ REG_FREQ_CALLS_CROSSED (dregno) += d_freq_calls;
}
}
rtx set;
int sregno = REGNO (src);
int dregno = REGNO (dest);
+ basic_block bb = BLOCK_FOR_INSN (insn);
for (p = NEXT_INSN (insn); p; p = NEXT_INSN (p))
{
- /* ??? We can't scan past the end of a basic block without updating
- the register lifetime info (REG_DEAD/basic_block_live_at_start). */
- if (perhaps_ends_bb_p (p))
- break;
- else if (! INSN_P (p))
+ if (! INSN_P (p))
continue;
+ if (BLOCK_FOR_INSN (p) != bb)
+ break;
set = single_set (p);
if (set && SET_SRC (set) == dest && SET_DEST (set) == src
if (INSN_P (q))
{
if (reg_mentioned_p (dest, PATTERN (q)))
- PATTERN (q) = replace_rtx (PATTERN (q), dest, src);
-
-
- if (GET_CODE (q) == CALL_INSN)
- {
- REG_N_CALLS_CROSSED (dregno)--;
- REG_N_CALLS_CROSSED (sregno)++;
- }
+ {
+ rtx note;
+
+ PATTERN (q) = replace_rtx (PATTERN (q), dest, src);
+ note = FIND_REG_INC_NOTE (q, dest);
+ if (note)
+ {
+ remove_note (q, note);
+ add_reg_note (q, REG_INC, src);
+ }
+ df_insn_rescan (q);
+ }
+
+ if (CALL_P (q))
+ {
+ int freq = REG_FREQ_FROM_BB (BLOCK_FOR_INSN (q));
+ REG_N_CALLS_CROSSED (dregno)--;
+ REG_N_CALLS_CROSSED (sregno)++;
+ REG_FREQ_CALLS_CROSSED (dregno) -= freq;
+ REG_FREQ_CALLS_CROSSED (sregno) += freq;
+ }
}
remove_note (p, find_reg_note (p, REG_DEAD, dest));
if (reg_set_p (src, p)
|| find_reg_note (p, REG_DEAD, dest)
- || (GET_CODE (p) == CALL_INSN && REG_N_CALLS_CROSSED (sregno) == 0))
+ || (CALL_P (p) && REG_N_CALLS_CROSSED (sregno) == 0))
break;
}
}
+
/* INSN is a ZERO_EXTEND or SIGN_EXTEND of SRC to DEST.
Look if SRC dies there, and if it is only set once, by loading
it from memory. If so, try to incorporate the zero/sign extension
rtx src_reg = XEXP (src, 0);
int src_no = REGNO (src_reg);
int dst_no = REGNO (dest);
- rtx p, set, subreg;
+ rtx p, set;
enum machine_mode old_mode;
+ basic_block bb = BLOCK_FOR_INSN (insn);
if (src_no < FIRST_PSEUDO_REGISTER
|| dst_no < FIRST_PSEUDO_REGISTER
|| REG_N_DEATHS (src_no) != 1
|| REG_N_SETS (src_no) != 1)
return;
+
for (p = PREV_INSN (insn); p && ! reg_set_p (src_reg, p); p = PREV_INSN (p))
- /* ??? We can't scan past the end of a basic block without updating
- the register lifetime info (REG_DEAD/basic_block_live_at_start). */
- if (perhaps_ends_bb_p (p))
+ if (INSN_P (p) && BLOCK_FOR_INSN (p) != bb)
break;
-
- if (! p)
+
+ if (! p || BLOCK_FOR_INSN (p) != bb)
return;
if (! (set = single_set (p))
- || GET_CODE (SET_SRC (set)) != MEM
+ || !MEM_P (SET_SRC (set))
/* If there's a REG_EQUIV note, this must be an insn that loads an
argument. Prefer keeping the note over doing this optimization. */
|| find_reg_note (p, REG_EQUIV, NULL_RTX)
/* Now walk forward making additional replacements. We want to be able
to undo all the changes if a later substitution fails. */
- subreg = gen_lowpart_SUBREG (old_mode, src_reg);
while (p = NEXT_INSN (p), p != insn)
{
if (! INSN_P (p))
continue;
- /* Make a tenative change. */
- validate_replace_rtx_group (src_reg, subreg, p);
+ /* Make a tentative change. */
+ validate_replace_rtx_group (src_reg,
+ gen_lowpart_SUBREG (old_mode, src_reg),
+ p);
}
validate_replace_rtx_group (src, src_reg, insn);
instead moving the value to dest directly before the operation. */
static void
-copy_src_to_dest (rtx insn, rtx src, rtx dest, int old_max_uid)
+copy_src_to_dest (rtx insn, rtx src, rtx dest)
{
rtx seq;
rtx link;
rtx *p_move_notes;
int src_regno;
int dest_regno;
- int bb;
int insn_uid;
int move_uid;
parameter when there is no frame pointer that is not allocated a register.
For now, we just reject them, rather than incrementing the live length. */
- if (GET_CODE (src) == REG
+ if (REG_P (src)
&& REG_LIVE_LENGTH (REGNO (src)) > 0
- && GET_CODE (dest) == REG
- && !RTX_UNCHANGING_P (dest)
+ && REG_P (dest)
&& REG_LIVE_LENGTH (REGNO (dest)) > 0
&& (set = single_set (insn)) != NULL_RTX
&& !reg_mentioned_p (dest, SET_SRC (set))
*p_move_notes = NULL_RTX;
*p_insn_notes = NULL_RTX;
- /* Is the insn the head of a basic block? If so extend it. */
insn_uid = INSN_UID (insn);
move_uid = INSN_UID (move_insn);
- if (insn_uid < old_max_uid)
- {
- bb = regmove_bb_head[insn_uid];
- if (bb >= 0)
- {
- BLOCK_HEAD (bb) = move_insn;
- regmove_bb_head[insn_uid] = -1;
- }
- }
/* Update the various register tables. */
dest_regno = REGNO (dest);
- REG_N_SETS (dest_regno) ++;
+ INC_REG_N_SETS (dest_regno, 1);
REG_LIVE_LENGTH (dest_regno)++;
- if (REGNO_FIRST_UID (dest_regno) == insn_uid)
- REGNO_FIRST_UID (dest_regno) = move_uid;
-
src_regno = REGNO (src);
if (! find_reg_note (move_insn, REG_DEAD, src))
REG_LIVE_LENGTH (src_regno)++;
+ }
+}
- if (REGNO_FIRST_UID (src_regno) == insn_uid)
- REGNO_FIRST_UID (src_regno) = move_uid;
+/* reg_set_in_bb[REGNO] points to basic block iff the register is set
+ only once in the given block and has REG_EQUAL note. */
- if (REGNO_LAST_UID (src_regno) == insn_uid)
- REGNO_LAST_UID (src_regno) = move_uid;
+static basic_block *reg_set_in_bb;
- if (REGNO_LAST_NOTE_UID (src_regno) == insn_uid)
- REGNO_LAST_NOTE_UID (src_regno) = move_uid;
- }
-}
+/* Size of reg_set_in_bb array. */
+static unsigned int max_reg_computed;
\f
/* Return whether REG is set in only one location, and is set to a
may increase register pressure and make reload harder. If REG is
set in the same basic block as INSN, we don't worry about it,
because we'll probably need a register anyhow (??? but what if REG
- is used in a different basic block as well as this one?). FIRST is
- the first insn in the function. */
+ is used in a different basic block as well as this one?). */
-static int
-reg_is_remote_constant_p (rtx reg, rtx insn, rtx first)
+static bool
+reg_is_remote_constant_p (rtx reg, rtx insn)
{
+ basic_block bb;
rtx p;
+ int max;
- if (REG_N_SETS (REGNO (reg)) != 1)
- return 0;
-
- /* Look for the set. */
- for (p = LOG_LINKS (insn); p; p = XEXP (p, 1))
+ if (!reg_set_in_bb)
{
- rtx s;
+ max_reg_computed = max = max_reg_num ();
+ reg_set_in_bb = XCNEWVEC (basic_block, max);
- if (REG_NOTE_KIND (p) != 0)
- continue;
- s = single_set (XEXP (p, 0));
- if (s != 0
- && GET_CODE (SET_DEST (s)) == REG
- && REGNO (SET_DEST (s)) == REGNO (reg))
- {
- /* The register is set in the same basic block. */
- return 0;
- }
- }
+ FOR_EACH_BB (bb)
+ FOR_BB_INSNS (bb, p)
+ {
+ rtx s;
- for (p = first; p && p != insn; p = NEXT_INSN (p))
- {
- rtx s;
-
- if (! INSN_P (p))
- continue;
- s = single_set (p);
- if (s != 0
- && GET_CODE (SET_DEST (s)) == REG
- && REGNO (SET_DEST (s)) == REGNO (reg))
- {
- /* This is the instruction which sets REG. If there is a
- REG_EQUAL note, then REG is equivalent to a constant. */
- if (find_reg_note (p, REG_EQUAL, NULL_RTX))
- return 1;
- return 0;
- }
+ if (!INSN_P (p))
+ continue;
+ s = single_set (p);
+ /* This is the instruction which sets REG. If there is a
+ REG_EQUAL note, then REG is equivalent to a constant. */
+ if (s != 0
+ && REG_P (SET_DEST (s))
+ && REG_N_SETS (REGNO (SET_DEST (s))) == 1
+ && find_reg_note (p, REG_EQUAL, NULL_RTX))
+ reg_set_in_bb[REGNO (SET_DEST (s))] = bb;
+ }
}
- return 0;
+ gcc_assert (REGNO (reg) < max_reg_computed);
+ if (reg_set_in_bb[REGNO (reg)] == NULL)
+ return false;
+ return (reg_set_in_bb[REGNO (reg)] != BLOCK_FOR_INSN (insn));
}
/* INSN is adding a CONST_INT to a REG. We search backwards looking for
hard register as ultimate source, like the frame pointer. */
static int
-fixup_match_2 (rtx insn, rtx dst, rtx src, rtx offset, FILE *regmove_dump_file)
+fixup_match_2 (rtx insn, rtx dst, rtx src, rtx offset)
{
rtx p, dst_death = 0;
- int length, num_calls = 0;
+ int length, num_calls = 0, freq_calls = 0;
+ basic_block bb = BLOCK_FOR_INSN (insn);
/* If SRC dies in INSN, we'd have to move the death note. This is
considered to be very unlikely, so we just skip the optimization
{
rtx pset;
- /* ??? We can't scan past the end of a basic block without updating
- the register lifetime info (REG_DEAD/basic_block_live_at_start). */
- if (perhaps_ends_bb_p (p))
- break;
- else if (! INSN_P (p))
+ if (! INSN_P (p))
continue;
+ if (BLOCK_FOR_INSN (p) != bb)
+ break;
if (find_regno_note (p, REG_DEAD, REGNO (dst)))
dst_death = p;
remove_death (REGNO (dst), dst_death);
REG_LIVE_LENGTH (REGNO (dst)) += length;
REG_N_CALLS_CROSSED (REGNO (dst)) += num_calls;
+ REG_FREQ_CALLS_CROSSED (REGNO (dst)) += freq_calls;
}
- if (regmove_dump_file)
- fprintf (regmove_dump_file,
+ if (dump_file)
+ fprintf (dump_file,
"Fixed operand of insn %d.\n",
INSN_UID (insn));
#ifdef AUTO_INC_DEC
for (p = PREV_INSN (insn); p; p = PREV_INSN (p))
{
- if (GET_CODE (p) == CODE_LABEL
- || GET_CODE (p) == JUMP_INSN)
- break;
if (! INSN_P (p))
continue;
+ if (BLOCK_FOR_INSN (p) != bb)
+ break;
if (reg_overlap_mentioned_p (dst, PATTERN (p)))
{
if (try_auto_increment (p, insn, 0, dst, newconst, 0))
}
for (p = NEXT_INSN (insn); p; p = NEXT_INSN (p))
{
- if (GET_CODE (p) == CODE_LABEL
- || GET_CODE (p) == JUMP_INSN)
- break;
if (! INSN_P (p))
continue;
+ if (BLOCK_FOR_INSN (p) != bb)
+ break;
if (reg_overlap_mentioned_p (dst, PATTERN (p)))
{
try_auto_increment (p, insn, 0, dst, newconst, 1);
/* reg_set_p is overly conservative for CALL_INSNS, thinks that all
hard regs are clobbered. Thus, we only use it for src for
non-call insns. */
- if (GET_CODE (p) == CALL_INSN)
+ if (CALL_P (p))
{
if (! dst_death)
- num_calls++;
+ {
+ num_calls++;
+ freq_calls += REG_FREQ_FROM_BB (BLOCK_FOR_INSN (p));
+ }
if (REG_N_CALLS_CROSSED (REGNO (src)) == 0)
break;
return 0;
}
-/* Main entry for the register move optimization.
- F is the first instruction.
- NREGS is one plus the highest pseudo-reg number used in the instruction.
- REGMOVE_DUMP_FILE is a stream for output of a trace of actions taken
- (or 0 if none should be output). */
+/* A forward pass. Replace output operands with input operands. */
-void
-regmove_optimize (rtx f, int nregs, FILE *regmove_dump_file)
+static void
+regmove_forward_pass (void)
{
- int old_max_uid = get_max_uid ();
- rtx insn;
- struct match match;
- int pass;
- int i;
- rtx copy_src, copy_dst;
basic_block bb;
+ rtx insn;
- /* ??? Hack. Regmove doesn't examine the CFG, and gets mightily
- confused by non-call exceptions ending blocks. */
- if (flag_non_call_exceptions)
+ if (! flag_expensive_optimizations)
return;
- /* Find out where a potential flags register is live, and so that we
- can suppress some optimizations in those zones. */
- mark_flags_life_zones (discover_flags_reg ());
+ if (dump_file)
+ fprintf (dump_file, "Starting forward pass...\n");
- regno_src_regno = (int *) xmalloc (sizeof *regno_src_regno * nregs);
- for (i = nregs; --i >= 0; ) regno_src_regno[i] = -1;
-
- regmove_bb_head = (int *) xmalloc (sizeof (int) * (old_max_uid + 1));
- for (i = old_max_uid; i >= 0; i--) regmove_bb_head[i] = -1;
FOR_EACH_BB (bb)
- regmove_bb_head[INSN_UID (bb->head)] = bb->index;
-
- /* A forward/backward pass. Replace output operands with input operands. */
-
- for (pass = 0; pass <= 2; pass++)
{
- if (! flag_regmove && pass >= flag_expensive_optimizations)
- goto done;
-
- if (regmove_dump_file)
- fprintf (regmove_dump_file, "Starting %s pass...\n",
- pass ? "backward" : "forward");
-
- for (insn = pass ? get_last_insn () : f; insn;
- insn = pass ? PREV_INSN (insn) : NEXT_INSN (insn))
+ FOR_BB_INSNS (bb, insn)
{
- rtx set;
- int op_no, match_no;
-
- set = single_set (insn);
+ rtx set = single_set (insn);
if (! set)
continue;
- if (flag_expensive_optimizations && ! pass
- && (GET_CODE (SET_SRC (set)) == SIGN_EXTEND
- || GET_CODE (SET_SRC (set)) == ZERO_EXTEND)
- && GET_CODE (XEXP (SET_SRC (set), 0)) == REG
- && GET_CODE (SET_DEST (set)) == REG)
+ if ((GET_CODE (SET_SRC (set)) == SIGN_EXTEND
+ || GET_CODE (SET_SRC (set)) == ZERO_EXTEND)
+ && REG_P (XEXP (SET_SRC (set), 0))
+ && REG_P (SET_DEST (set)))
optimize_reg_copy_3 (insn, SET_DEST (set), SET_SRC (set));
- if (flag_expensive_optimizations && ! pass
- && GET_CODE (SET_SRC (set)) == REG
- && GET_CODE (SET_DEST (set)) == REG)
+ if (REG_P (SET_SRC (set))
+ && REG_P (SET_DEST (set)))
{
/* If this is a register-register copy where SRC is not dead,
see if we can optimize it. If this optimization succeeds,
}
}
}
- if (! flag_regmove)
- continue;
-
- if (! find_matches (insn, &match))
- continue;
-
- /* Now scan through the operands looking for a source operand
- which is supposed to match the destination operand.
- Then scan forward for an instruction which uses the dest
- operand.
- If it dies there, then replace the dest in both operands with
- the source operand. */
-
- for (op_no = 0; op_no < recog_data.n_operands; op_no++)
- {
- rtx src, dst, src_subreg;
- enum reg_class src_class, dst_class;
-
- match_no = match.with[op_no];
-
- /* Nothing to do if the two operands aren't supposed to match. */
- if (match_no < 0)
- continue;
-
- src = recog_data.operand[op_no];
- dst = recog_data.operand[match_no];
-
- if (GET_CODE (src) != REG)
- continue;
-
- src_subreg = src;
- if (GET_CODE (dst) == SUBREG
- && GET_MODE_SIZE (GET_MODE (dst))
- >= GET_MODE_SIZE (GET_MODE (SUBREG_REG (dst))))
- {
- src_subreg
- = gen_rtx_SUBREG (GET_MODE (SUBREG_REG (dst)),
- src, SUBREG_BYTE (dst));
- dst = SUBREG_REG (dst);
- }
- if (GET_CODE (dst) != REG
- || REGNO (dst) < FIRST_PSEUDO_REGISTER)
- continue;
-
- if (REGNO (src) < FIRST_PSEUDO_REGISTER)
- {
- if (match.commutative[op_no] < op_no)
- regno_src_regno[REGNO (dst)] = REGNO (src);
- continue;
- }
-
- if (REG_LIVE_LENGTH (REGNO (src)) < 0)
- continue;
-
- /* op_no/src must be a read-only operand, and
- match_operand/dst must be a write-only operand. */
- if (match.use[op_no] != READ
- || match.use[match_no] != WRITE)
- continue;
-
- if (match.early_clobber[match_no]
- && count_occurrences (PATTERN (insn), src, 0) > 1)
- continue;
-
- /* Make sure match_operand is the destination. */
- if (recog_data.operand[match_no] != SET_DEST (set))
- continue;
-
- /* If the operands already match, then there is nothing to do. */
- if (operands_match_p (src, dst))
- continue;
-
- /* But in the commutative case, we might find a better match. */
- if (match.commutative[op_no] >= 0)
- {
- rtx comm = recog_data.operand[match.commutative[op_no]];
- if (operands_match_p (comm, dst)
- && (replacement_quality (comm)
- >= replacement_quality (src)))
- continue;
- }
-
- src_class = reg_preferred_class (REGNO (src));
- dst_class = reg_preferred_class (REGNO (dst));
- if (! regclass_compatible_p (src_class, dst_class))
- continue;
-
- if (GET_MODE (src) != GET_MODE (dst))
- continue;
-
- if (fixup_match_1 (insn, set, src, src_subreg, dst, pass,
- op_no, match_no,
- regmove_dump_file))
- break;
- }
}
}
+}
- /* A backward pass. Replace input operands with output operands. */
+/* A backward pass. Replace input operands with output operands. */
+
+static void
+regmove_backward_pass (void)
+{
+ basic_block bb;
+ rtx insn, prev;
- if (regmove_dump_file)
- fprintf (regmove_dump_file, "Starting backward pass...\n");
+ if (dump_file)
+ fprintf (dump_file, "Starting backward pass...\n");
- for (insn = get_last_insn (); insn; insn = PREV_INSN (insn))
+ FOR_EACH_BB_REVERSE (bb)
{
- if (INSN_P (insn))
+ /* ??? Use the safe iterator because fixup_match_2 can remove
+ insns via try_auto_increment. */
+ FOR_BB_INSNS_REVERSE_SAFE (bb, insn, prev)
{
+ struct match match;
+ rtx copy_src, copy_dst;
int op_no, match_no;
int success = 0;
+ if (! INSN_P (insn))
+ continue;
+
if (! find_matches (insn, &match))
continue;
{
rtx set, p, src, dst;
rtx src_note, dst_note;
- int num_calls = 0;
+ int num_calls = 0, freq_calls = 0;
enum reg_class src_class, dst_class;
int length;
dst = recog_data.operand[match_no];
src = recog_data.operand[op_no];
- if (GET_CODE (src) != REG)
+ if (!REG_P (src))
continue;
- if (GET_CODE (dst) != REG
+ if (!REG_P (dst)
|| REGNO (dst) < FIRST_PSEUDO_REGISTER
|| REG_LIVE_LENGTH (REGNO (dst)) < 0
- || RTX_UNCHANGING_P (dst)
|| GET_MODE (src) != GET_MODE (dst))
continue;
&& GET_CODE (XEXP (SET_SRC (set), 1)) == CONST_INT
&& XEXP (SET_SRC (set), 0) == src
&& fixup_match_2 (insn, dst, src,
- XEXP (SET_SRC (set), 1),
- regmove_dump_file))
+ XEXP (SET_SRC (set), 1)))
break;
continue;
}
it for this optimization, as this would make it
no longer equivalent to a constant. */
- if (reg_is_remote_constant_p (src, insn, f))
+ if (reg_is_remote_constant_p (src, insn))
{
if (!copy_src)
{
}
- if (regmove_dump_file)
- fprintf (regmove_dump_file,
+ if (dump_file)
+ fprintf (dump_file,
"Could fix operand %d of insn %d matching operand %d.\n",
op_no, INSN_UID (insn), match_no);
{
rtx pset;
- /* ??? We can't scan past the end of a basic block without
- updating the register lifetime info
- (REG_DEAD/basic_block_live_at_start). */
- if (perhaps_ends_bb_p (p))
- break;
- else if (! INSN_P (p))
+ if (! INSN_P (p))
continue;
+ if (BLOCK_FOR_INSN (p) != bb)
+ break;
length++;
break;
}
+ /* We can't make this change if SRC is read or
+ partially written in P, since we are going to
+ eliminate SRC. We can't make this change
+ if DST is mentioned at all in P,
+ since we are going to change its value. */
if (reg_overlap_mentioned_p (src, PATTERN (p))
- || reg_overlap_mentioned_p (dst, PATTERN (p)))
+ || reg_mentioned_p (dst, PATTERN (p)))
break;
/* If we have passed a call instruction, and the
pseudo-reg DST is not already live across a call,
then don't perform the optimization. */
- if (GET_CODE (p) == CALL_INSN)
+ if (CALL_P (p))
{
num_calls++;
+ freq_calls += REG_FREQ_FROM_BB (BLOCK_FOR_INSN (p));
if (REG_N_CALLS_CROSSED (REGNO (dst)) == 0)
break;
dstno = REGNO (dst);
srcno = REGNO (src);
- REG_N_SETS (dstno)++;
- REG_N_SETS (srcno)--;
+ INC_REG_N_SETS (dstno, 1);
+ INC_REG_N_SETS (srcno, -1);
REG_N_CALLS_CROSSED (dstno) += num_calls;
REG_N_CALLS_CROSSED (srcno) -= num_calls;
+ REG_FREQ_CALLS_CROSSED (dstno) += freq_calls;
+ REG_FREQ_CALLS_CROSSED (srcno) -= freq_calls;
REG_LIVE_LENGTH (dstno) += length;
if (REG_LIVE_LENGTH (srcno) >= 0)
REG_LIVE_LENGTH (srcno) = 2;
}
- if (regmove_dump_file)
- fprintf (regmove_dump_file,
+ if (dump_file)
+ fprintf (dump_file,
"Fixed operand %d of insn %d matching operand %d.\n",
op_no, INSN_UID (insn), match_no);
/* If we weren't able to replace any of the alternatives, try an
alternative approach of copying the source to the destination. */
if (!success && copy_src != NULL_RTX)
- copy_src_to_dest (insn, copy_src, copy_dst, old_max_uid);
-
+ copy_src_to_dest (insn, copy_src, copy_dst);
}
}
+}
- /* In fixup_match_1, some insns may have been inserted after basic block
- ends. Fix that here. */
- FOR_EACH_BB (bb)
- {
- rtx end = bb->end;
- rtx new = end;
- rtx next = NEXT_INSN (new);
- while (next != 0 && INSN_UID (next) >= old_max_uid
- && (bb->next_bb == EXIT_BLOCK_PTR || bb->next_bb->head != next))
- new = next, next = NEXT_INSN (new);
- bb->end = new;
- }
+/* Main entry for the register move optimization. */
+
+static unsigned int
+regmove_optimize (void)
+{
+ int i;
+ int nregs = max_reg_num ();
+
+ df_note_add_problem ();
+ df_analyze ();
+
+ regstat_init_n_sets_and_refs ();
+ regstat_compute_ri ();
+
+ regno_src_regno = XNEWVEC (int, nregs);
+ for (i = nregs; --i >= 0; )
+ regno_src_regno[i] = -1;
+
+ /* A forward pass. Replace output operands with input operands. */
+ regmove_forward_pass ();
+
+ /* A backward pass. Replace input operands with output operands. */
+ regmove_backward_pass ();
- done:
/* Clean up. */
free (regno_src_regno);
- free (regmove_bb_head);
+ if (reg_set_in_bb)
+ {
+ free (reg_set_in_bb);
+ reg_set_in_bb = NULL;
+ }
+ regstat_free_n_sets_and_refs ();
+ regstat_free_ri ();
+ return 0;
}
/* Returns nonzero if INSN's pattern has matching constraints for any operand.
return any_matches;
}
-/* Try to replace all occurrences of DST_REG with SRC in LOC, that is
- assumed to be in INSN. */
-
-static void
-replace_in_call_usage (rtx *loc, unsigned int dst_reg, rtx src, rtx insn)
-{
- rtx x = *loc;
- enum rtx_code code;
- const char *fmt;
- int i, j;
-
- if (! x)
- return;
-
- code = GET_CODE (x);
- if (code == REG)
- {
- if (REGNO (x) != dst_reg)
- return;
-
- validate_change (insn, loc, src, 1);
-
- return;
- }
-
- /* Process each of our operands recursively. */
- fmt = GET_RTX_FORMAT (code);
- for (i = 0; i < GET_RTX_LENGTH (code); i++, fmt++)
- if (*fmt == 'e')
- replace_in_call_usage (&XEXP (x, i), dst_reg, src, insn);
- else if (*fmt == 'E')
- for (j = 0; j < XVECLEN (x, i); j++)
- replace_in_call_usage (& XVECEXP (x, i, j), dst_reg, src, insn);
-}
-
-/* Try to replace output operand DST in SET, with input operand SRC. SET is
- the only set in INSN. INSN has just been recognized and constrained.
- SRC is operand number OPERAND_NUMBER in INSN.
- DST is operand number MATCH_NUMBER in INSN.
- If BACKWARD is nonzero, we have been called in a backward pass.
- Return nonzero for success. */
-
-static int
-fixup_match_1 (rtx insn, rtx set, rtx src, rtx src_subreg, rtx dst,
- int backward, int operand_number, int match_number,
- FILE *regmove_dump_file)
-{
- rtx p;
- rtx post_inc = 0, post_inc_set = 0, search_end = 0;
- int success = 0;
- int num_calls = 0, s_num_calls = 0;
- enum rtx_code code = NOTE;
- HOST_WIDE_INT insn_const = 0, newconst = 0;
- rtx overlap = 0; /* need to move insn ? */
- rtx src_note = find_reg_note (insn, REG_DEAD, src), dst_note = NULL_RTX;
- int length, s_length;
-
- /* If SRC is marked as unchanging, we may not change it.
- ??? Maybe we could get better code by removing the unchanging bit
- instead, and changing it back if we don't succeed? */
- if (RTX_UNCHANGING_P (src))
- return 0;
-
- if (! src_note)
- {
- /* Look for (set (regX) (op regA constX))
- (set (regY) (op regA constY))
- and change that to
- (set (regA) (op regA constX)).
- (set (regY) (op regA constY-constX)).
- This works for add and shift operations, if
- regA is dead after or set by the second insn. */
-
- code = GET_CODE (SET_SRC (set));
- if ((code == PLUS || code == LSHIFTRT
- || code == ASHIFT || code == ASHIFTRT)
- && XEXP (SET_SRC (set), 0) == src
- && GET_CODE (XEXP (SET_SRC (set), 1)) == CONST_INT)
- insn_const = INTVAL (XEXP (SET_SRC (set), 1));
- else if (! stable_and_no_regs_but_for_p (SET_SRC (set), src, dst))
- return 0;
- else
- /* We might find a src_note while scanning. */
- code = NOTE;
- }
-
- if (regmove_dump_file)
- fprintf (regmove_dump_file,
- "Could fix operand %d of insn %d matching operand %d.\n",
- operand_number, INSN_UID (insn), match_number);
-
- /* If SRC is equivalent to a constant set in a different basic block,
- then do not use it for this optimization. We want the equivalence
- so that if we have to reload this register, we can reload the
- constant, rather than extending the lifespan of the register. */
- if (reg_is_remote_constant_p (src, insn, get_insns ()))
- return 0;
-
- /* Scan forward to find the next instruction that
- uses the output operand. If the operand dies here,
- then replace it in both instructions with
- operand_number. */
-
- for (length = s_length = 0, p = NEXT_INSN (insn); p; p = NEXT_INSN (p))
- {
- if (GET_CODE (p) == CALL_INSN)
- replace_in_call_usage (& CALL_INSN_FUNCTION_USAGE (p),
- REGNO (dst), src, p);
-
- /* ??? We can't scan past the end of a basic block without updating
- the register lifetime info (REG_DEAD/basic_block_live_at_start). */
- if (perhaps_ends_bb_p (p))
- break;
- else if (! INSN_P (p))
- continue;
-
- length++;
- if (src_note)
- s_length++;
-
- if (reg_set_p (src, p) || reg_set_p (dst, p)
- || (GET_CODE (PATTERN (p)) == USE
- && reg_overlap_mentioned_p (src, XEXP (PATTERN (p), 0))))
- break;
-
- /* See if all of DST dies in P. This test is
- slightly more conservative than it needs to be. */
- if ((dst_note = find_regno_note (p, REG_DEAD, REGNO (dst)))
- && (GET_MODE (XEXP (dst_note, 0)) == GET_MODE (dst)))
- {
- /* If we would be moving INSN, check that we won't move it
- into the shadow of a live a live flags register. */
- /* ??? We only try to move it in front of P, although
- we could move it anywhere between OVERLAP and P. */
- if (overlap && GET_MODE (PREV_INSN (p)) != VOIDmode)
- break;
-
- if (! src_note)
- {
- rtx q;
- rtx set2 = NULL_RTX;
-
- /* If an optimization is done, the value of SRC while P
- is executed will be changed. Check that this is OK. */
- if (reg_overlap_mentioned_p (src, PATTERN (p)))
- break;
- for (q = p; q; q = NEXT_INSN (q))
- {
- /* ??? We can't scan past the end of a basic block without
- updating the register lifetime info
- (REG_DEAD/basic_block_live_at_start). */
- if (perhaps_ends_bb_p (q))
- {
- q = 0;
- break;
- }
- else if (! INSN_P (q))
- continue;
- else if (reg_overlap_mentioned_p (src, PATTERN (q))
- || reg_set_p (src, q))
- break;
- }
- if (q)
- set2 = single_set (q);
- if (! q || ! set2 || GET_CODE (SET_SRC (set2)) != code
- || XEXP (SET_SRC (set2), 0) != src
- || GET_CODE (XEXP (SET_SRC (set2), 1)) != CONST_INT
- || (SET_DEST (set2) != src
- && ! find_reg_note (q, REG_DEAD, src)))
- {
- /* If this is a PLUS, we can still save a register by doing
- src += insn_const;
- P;
- src -= insn_const; .
- This also gives opportunities for subsequent
- optimizations in the backward pass, so do it there. */
- if (code == PLUS && backward
- /* Don't do this if we can likely tie DST to SET_DEST
- of P later; we can't do this tying here if we got a
- hard register. */
- && ! (dst_note && ! REG_N_CALLS_CROSSED (REGNO (dst))
- && single_set (p)
- && GET_CODE (SET_DEST (single_set (p))) == REG
- && (REGNO (SET_DEST (single_set (p)))
- < FIRST_PSEUDO_REGISTER))
- /* We may only emit an insn directly after P if we
- are not in the shadow of a live flags register. */
- && GET_MODE (p) == VOIDmode)
- {
- search_end = q;
- q = insn;
- set2 = set;
- newconst = -insn_const;
- code = MINUS;
- }
- else
- break;
- }
- else
- {
- newconst = INTVAL (XEXP (SET_SRC (set2), 1)) - insn_const;
- /* Reject out of range shifts. */
- if (code != PLUS
- && (newconst < 0
- || ((unsigned HOST_WIDE_INT) newconst
- >= (GET_MODE_BITSIZE (GET_MODE
- (SET_SRC (set2)))))))
- break;
- if (code == PLUS)
- {
- post_inc = q;
- if (SET_DEST (set2) != src)
- post_inc_set = set2;
- }
- }
- /* We use 1 as last argument to validate_change so that all
- changes are accepted or rejected together by apply_change_group
- when it is called by validate_replace_rtx . */
- validate_change (q, &XEXP (SET_SRC (set2), 1),
- GEN_INT (newconst), 1);
- }
- validate_change (insn, recog_data.operand_loc[match_number], src, 1);
- if (validate_replace_rtx (dst, src_subreg, p))
- success = 1;
- break;
- }
-
- if (reg_overlap_mentioned_p (dst, PATTERN (p)))
- break;
- if (! src_note && reg_overlap_mentioned_p (src, PATTERN (p)))
- {
- /* INSN was already checked to be movable wrt. the registers that it
- sets / uses when we found no REG_DEAD note for src on it, but it
- still might clobber the flags register. We'll have to check that
- we won't insert it into the shadow of a live flags register when
- we finally know where we are to move it. */
- overlap = p;
- src_note = find_reg_note (p, REG_DEAD, src);
- }
-
- /* If we have passed a call instruction, and the pseudo-reg SRC is not
- already live across a call, then don't perform the optimization. */
- if (GET_CODE (p) == CALL_INSN)
- {
- if (REG_N_CALLS_CROSSED (REGNO (src)) == 0)
- break;
-
- num_calls++;
-
- if (src_note)
- s_num_calls++;
-
- }
- }
-
- if (! success)
- return 0;
-
- /* Remove the death note for DST from P. */
- remove_note (p, dst_note);
- if (code == MINUS)
- {
- post_inc = emit_insn_after (copy_rtx (PATTERN (insn)), p);
- if ((HAVE_PRE_INCREMENT || HAVE_PRE_DECREMENT)
- && search_end
- && try_auto_increment (search_end, post_inc, 0, src, newconst, 1))
- post_inc = 0;
- validate_change (insn, &XEXP (SET_SRC (set), 1), GEN_INT (insn_const), 0);
- REG_N_SETS (REGNO (src))++;
- REG_LIVE_LENGTH (REGNO (src))++;
- }
- if (overlap)
- {
- /* The lifetime of src and dest overlap,
- but we can change this by moving insn. */
- rtx pat = PATTERN (insn);
- if (src_note)
- remove_note (overlap, src_note);
- if ((HAVE_POST_INCREMENT || HAVE_POST_DECREMENT)
- && code == PLUS
- && try_auto_increment (overlap, insn, 0, src, insn_const, 0))
- insn = overlap;
- else
- {
- rtx notes = REG_NOTES (insn);
-
- emit_insn_after_with_line_notes (pat, PREV_INSN (p), insn);
- delete_insn (insn);
- /* emit_insn_after_with_line_notes has no
- return value, so search for the new insn. */
- insn = p;
- while (! INSN_P (insn) || PATTERN (insn) != pat)
- insn = PREV_INSN (insn);
-
- REG_NOTES (insn) = notes;
- }
- }
- /* Sometimes we'd generate src = const; src += n;
- if so, replace the instruction that set src
- in the first place. */
-
- if (! overlap && (code == PLUS || code == MINUS))
- {
- rtx note = find_reg_note (insn, REG_EQUAL, NULL_RTX);
- rtx q, set2 = NULL_RTX;
- int num_calls2 = 0, s_length2 = 0;
-
- if (note && CONSTANT_P (XEXP (note, 0)))
- {
- for (q = PREV_INSN (insn); q; q = PREV_INSN (q))
- {
- /* ??? We can't scan past the end of a basic block without
- updating the register lifetime info
- (REG_DEAD/basic_block_live_at_start). */
- if (perhaps_ends_bb_p (q))
- {
- q = 0;
- break;
- }
- else if (! INSN_P (q))
- continue;
-
- s_length2++;
- if (reg_set_p (src, q))
- {
- set2 = single_set (q);
- break;
- }
- if (reg_overlap_mentioned_p (src, PATTERN (q)))
- {
- q = 0;
- break;
- }
- if (GET_CODE (p) == CALL_INSN)
- num_calls2++;
- }
- if (q && set2 && SET_DEST (set2) == src && CONSTANT_P (SET_SRC (set2))
- && validate_change (insn, &SET_SRC (set), XEXP (note, 0), 0))
- {
- delete_insn (q);
- REG_N_SETS (REGNO (src))--;
- REG_N_CALLS_CROSSED (REGNO (src)) -= num_calls2;
- REG_LIVE_LENGTH (REGNO (src)) -= s_length2;
- insn_const = 0;
- }
- }
- }
-
- if ((HAVE_PRE_INCREMENT || HAVE_PRE_DECREMENT)
- && (code == PLUS || code == MINUS) && insn_const
- && try_auto_increment (p, insn, 0, src, insn_const, 1))
- insn = p;
- else if ((HAVE_POST_INCREMENT || HAVE_POST_DECREMENT)
- && post_inc
- && try_auto_increment (p, post_inc, post_inc_set, src, newconst, 0))
- post_inc = 0;
- /* If post_inc still prevails, try to find an
- insn where it can be used as a pre-in/decrement.
- If code is MINUS, this was already tried. */
- if (post_inc && code == PLUS
- /* Check that newconst is likely to be usable
- in a pre-in/decrement before starting the search. */
- && ((HAVE_PRE_INCREMENT && newconst > 0 && newconst <= MOVE_MAX)
- || (HAVE_PRE_DECREMENT && newconst < 0 && newconst >= -MOVE_MAX))
- && exact_log2 (newconst))
- {
- rtx q, inc_dest;
-
- inc_dest = post_inc_set ? SET_DEST (post_inc_set) : src;
- for (q = post_inc; (q = NEXT_INSN (q)); )
- {
- /* ??? We can't scan past the end of a basic block without updating
- the register lifetime info
- (REG_DEAD/basic_block_live_at_start). */
- if (perhaps_ends_bb_p (q))
- break;
- else if (! INSN_P (q))
- continue;
- else if (src != inc_dest
- && (reg_overlap_mentioned_p (src, PATTERN (q))
- || reg_set_p (src, q)))
- break;
- else if (reg_set_p (inc_dest, q))
- break;
- else if (reg_overlap_mentioned_p (inc_dest, PATTERN (q)))
- {
- try_auto_increment (q, post_inc,
- post_inc_set, inc_dest, newconst, 1);
- break;
- }
- }
- }
-
- /* Move the death note for DST to INSN if it is used
- there. */
- if (reg_overlap_mentioned_p (dst, PATTERN (insn)))
- {
- XEXP (dst_note, 1) = REG_NOTES (insn);
- REG_NOTES (insn) = dst_note;
- }
-
- if (src_note)
- {
- /* Move the death note for SRC from INSN to P. */
- if (! overlap)
- remove_note (insn, src_note);
- XEXP (src_note, 1) = REG_NOTES (p);
- REG_NOTES (p) = src_note;
-
- REG_N_CALLS_CROSSED (REGNO (src)) += s_num_calls;
- }
-
- REG_N_SETS (REGNO (src))++;
- REG_N_SETS (REGNO (dst))--;
-
- REG_N_CALLS_CROSSED (REGNO (dst)) -= num_calls;
-
- REG_LIVE_LENGTH (REGNO (src)) += s_length;
- if (REG_LIVE_LENGTH (REGNO (dst)) >= 0)
- {
- REG_LIVE_LENGTH (REGNO (dst)) -= length;
- /* REG_LIVE_LENGTH is only an approximation after
- combine if sched is not run, so make sure that we
- still have a reasonable value. */
- if (REG_LIVE_LENGTH (REGNO (dst)) < 2)
- REG_LIVE_LENGTH (REGNO (dst)) = 2;
- }
- if (regmove_dump_file)
- fprintf (regmove_dump_file,
- "Fixed operand %d of insn %d matching operand %d.\n",
- operand_number, INSN_UID (insn), match_number);
- return 1;
-}
-
-
-/* return nonzero if X is stable and mentions no registers but for
- mentioning SRC or mentioning / changing DST . If in doubt, presume
- it is unstable.
- The rationale is that we want to check if we can move an insn easily
- while just paying attention to SRC and DST. A register is considered
- stable if it has the RTX_UNCHANGING_P bit set, but that would still
- leave the burden to update REG_DEAD / REG_UNUSED notes, so we don't
- want any registers but SRC and DST. */
-static int
-stable_and_no_regs_but_for_p (rtx x, rtx src, rtx dst)
-{
- RTX_CODE code = GET_CODE (x);
- switch (GET_RTX_CLASS (code))
- {
- case '<': case '1': case 'c': case '2': case 'b': case '3':
- {
- int i;
- const char *fmt = GET_RTX_FORMAT (code);
- for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
- if (fmt[i] == 'e'
- && ! stable_and_no_regs_but_for_p (XEXP (x, i), src, dst))
- return 0;
- return 1;
- }
- case 'o':
- if (code == REG)
- return x == src || x == dst;
- /* If this is a MEM, look inside - there might be a register hidden in
- the address of an unchanging MEM. */
- if (code == MEM
- && ! stable_and_no_regs_but_for_p (XEXP (x, 0), src, dst))
- return 0;
- /* fall through */
- default:
- return ! rtx_unstable_p (x);
- }
-}
\f
-/* Track stack adjustments and stack memory references. Attempt to
- reduce the number of stack adjustments by back-propagating across
- the memory references.
-
- This is intended primarily for use with targets that do not define
- ACCUMULATE_OUTGOING_ARGS. It is of significantly more value to
- targets that define PREFERRED_STACK_BOUNDARY more aligned than
- STACK_BOUNDARY (e.g. x86), or if not all registers can be pushed
- (e.g. x86 fp regs) which would ordinarily have to be implemented
- as a sub/mov pair due to restrictions in calls.c.
-
- Propagation stops when any of the insns that need adjusting are
- (a) no longer valid because we've exceeded their range, (b) a
- non-trivial push instruction, or (c) a call instruction.
-
- Restriction B is based on the assumption that push instructions
- are smaller or faster. If a port really wants to remove all
- pushes, it should have defined ACCUMULATE_OUTGOING_ARGS. The
- one exception that is made is for an add immediately followed
- by a push. */
-
-/* This structure records stack memory references between stack adjusting
- instructions. */
-
-struct csa_memlist
-{
- HOST_WIDE_INT sp_offset;
- rtx insn, *mem;
- struct csa_memlist *next;
-};
-
-static int stack_memref_p (rtx);
-static rtx single_set_for_csa (rtx);
-static void free_csa_memlist (struct csa_memlist *);
-static struct csa_memlist *record_one_stack_memref (rtx, rtx *,
- struct csa_memlist *);
-static int try_apply_stack_adjustment (rtx, struct csa_memlist *,
- HOST_WIDE_INT, HOST_WIDE_INT);
-static void combine_stack_adjustments_for_block (basic_block);
-static int record_stack_memrefs (rtx *, void *);
-
-
-/* Main entry point for stack adjustment combination. */
-
-void
-combine_stack_adjustments (void)
-{
- basic_block bb;
-
- FOR_EACH_BB (bb)
- combine_stack_adjustments_for_block (bb);
-}
-
-/* Recognize a MEM of the form (sp) or (plus sp const). */
-
-static int
-stack_memref_p (rtx x)
-{
- if (GET_CODE (x) != MEM)
- return 0;
- x = XEXP (x, 0);
-
- if (x == stack_pointer_rtx)
- return 1;
- if (GET_CODE (x) == PLUS
- && XEXP (x, 0) == stack_pointer_rtx
- && GET_CODE (XEXP (x, 1)) == CONST_INT)
- return 1;
-
- return 0;
-}
-/* Recognize either normal single_set or the hack in i386.md for
- tying fp and sp adjustments. */
-
-static rtx
-single_set_for_csa (rtx insn)
+static bool
+gate_handle_regmove (void)
{
- int i;
- rtx tmp = single_set (insn);
- if (tmp)
- return tmp;
-
- if (GET_CODE (insn) != INSN
- || GET_CODE (PATTERN (insn)) != PARALLEL)
- return NULL_RTX;
-
- tmp = PATTERN (insn);
- if (GET_CODE (XVECEXP (tmp, 0, 0)) != SET)
- return NULL_RTX;
-
- for (i = 1; i < XVECLEN (tmp, 0); ++i)
- {
- rtx this = XVECEXP (tmp, 0, i);
-
- /* The special case is allowing a no-op set. */
- if (GET_CODE (this) == SET
- && SET_SRC (this) == SET_DEST (this))
- ;
- else if (GET_CODE (this) != CLOBBER
- && GET_CODE (this) != USE)
- return NULL_RTX;
- }
-
- return XVECEXP (tmp, 0, 0);
+ return (optimize > 0 && flag_regmove);
}
-/* Free the list of csa_memlist nodes. */
-
-static void
-free_csa_memlist (struct csa_memlist *memlist)
-{
- struct csa_memlist *next;
- for (; memlist ; memlist = next)
- {
- next = memlist->next;
- free (memlist);
- }
-}
-
-/* Create a new csa_memlist node from the given memory reference.
- It is already known that the memory is stack_memref_p. */
-
-static struct csa_memlist *
-record_one_stack_memref (rtx insn, rtx *mem, struct csa_memlist *next_memlist)
-{
- struct csa_memlist *ml;
-
- ml = (struct csa_memlist *) xmalloc (sizeof (*ml));
-
- if (XEXP (*mem, 0) == stack_pointer_rtx)
- ml->sp_offset = 0;
- else
- ml->sp_offset = INTVAL (XEXP (XEXP (*mem, 0), 1));
-
- ml->insn = insn;
- ml->mem = mem;
- ml->next = next_memlist;
-
- return ml;
-}
-
-/* Attempt to apply ADJUST to the stack adjusting insn INSN, as well
- as each of the memories in MEMLIST. Return true on success. */
-
-static int
-try_apply_stack_adjustment (rtx insn, struct csa_memlist *memlist, HOST_WIDE_INT new_adjust,
- HOST_WIDE_INT delta)
-{
- struct csa_memlist *ml;
- rtx set;
-
- set = single_set_for_csa (insn);
- validate_change (insn, &XEXP (SET_SRC (set), 1), GEN_INT (new_adjust), 1);
-
- for (ml = memlist; ml ; ml = ml->next)
- validate_change
- (ml->insn, ml->mem,
- replace_equiv_address_nv (*ml->mem,
- plus_constant (stack_pointer_rtx,
- ml->sp_offset - delta)), 1);
-
- if (apply_change_group ())
- {
- /* Succeeded. Update our knowledge of the memory references. */
- for (ml = memlist; ml ; ml = ml->next)
- ml->sp_offset -= delta;
-
- return 1;
- }
- else
- return 0;
-}
-/* Called via for_each_rtx and used to record all stack memory references in
- the insn and discard all other stack pointer references. */
-struct record_stack_memrefs_data
+struct rtl_opt_pass pass_regmove =
{
- rtx insn;
- struct csa_memlist *memlist;
+ {
+ RTL_PASS,
+ "regmove", /* name */
+ gate_handle_regmove, /* gate */
+ regmove_optimize, /* execute */
+ NULL, /* sub */
+ NULL, /* next */
+ 0, /* static_pass_number */
+ TV_REGMOVE, /* tv_id */
+ 0, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ TODO_df_finish | TODO_verify_rtl_sharing |
+ TODO_dump_func |
+ TODO_ggc_collect /* todo_flags_finish */
+ }
};
-static int
-record_stack_memrefs (rtx *xp, void *data)
-{
- rtx x = *xp;
- struct record_stack_memrefs_data *d =
- (struct record_stack_memrefs_data *) data;
- if (!x)
- return 0;
- switch (GET_CODE (x))
- {
- case MEM:
- if (!reg_mentioned_p (stack_pointer_rtx, x))
- return -1;
- /* We are not able to handle correctly all possible memrefs containing
- stack pointer, so this check is necessary. */
- if (stack_memref_p (x))
- {
- d->memlist = record_one_stack_memref (d->insn, xp, d->memlist);
- return -1;
- }
- return 1;
- case REG:
- /* ??? We want be able to handle non-memory stack pointer
- references later. For now just discard all insns referring to
- stack pointer outside mem expressions. We would probably
- want to teach validate_replace to simplify expressions first.
-
- We can't just compare with STACK_POINTER_RTX because the
- reference to the stack pointer might be in some other mode.
- In particular, an explicit clobber in an asm statement will
- result in a QImode clobber. */
- if (REGNO (x) == STACK_POINTER_REGNUM)
- return 1;
- break;
- default:
- break;
- }
- return 0;
-}
-
-/* Subroutine of combine_stack_adjustments, called for each basic block. */
-
-static void
-combine_stack_adjustments_for_block (basic_block bb)
-{
- HOST_WIDE_INT last_sp_adjust = 0;
- rtx last_sp_set = NULL_RTX;
- struct csa_memlist *memlist = NULL;
- rtx insn, next, set;
- struct record_stack_memrefs_data data;
- bool end_of_block = false;
-
- for (insn = bb->head; !end_of_block ; insn = next)
- {
- end_of_block = insn == bb->end;
- next = NEXT_INSN (insn);
-
- if (! INSN_P (insn))
- continue;
-
- set = single_set_for_csa (insn);
- if (set)
- {
- rtx dest = SET_DEST (set);
- rtx src = SET_SRC (set);
-
- /* Find constant additions to the stack pointer. */
- if (dest == stack_pointer_rtx
- && GET_CODE (src) == PLUS
- && XEXP (src, 0) == stack_pointer_rtx
- && GET_CODE (XEXP (src, 1)) == CONST_INT)
- {
- HOST_WIDE_INT this_adjust = INTVAL (XEXP (src, 1));
-
- /* If we've not seen an adjustment previously, record
- it now and continue. */
- if (! last_sp_set)
- {
- last_sp_set = insn;
- last_sp_adjust = this_adjust;
- continue;
- }
-
- /* If not all recorded memrefs can be adjusted, or the
- adjustment is now too large for a constant addition,
- we cannot merge the two stack adjustments.
-
- Also we need to be careful to not move stack pointer
- such that we create stack accesses outside the allocated
- area. We can combine an allocation into the first insn,
- or a deallocation into the second insn. We can not
- combine an allocation followed by a deallocation.
-
- The only somewhat frequent occurrence of the later is when
- a function allocates a stack frame but does not use it.
- For this case, we would need to analyze rtl stream to be
- sure that allocated area is really unused. This means not
- only checking the memory references, but also all registers
- or global memory references possibly containing a stack
- frame address.
-
- Perhaps the best way to address this problem is to teach
- gcc not to allocate stack for objects never used. */
-
- /* Combine an allocation into the first instruction. */
- if (STACK_GROWS_DOWNWARD ? this_adjust <= 0 : this_adjust >= 0)
- {
- if (try_apply_stack_adjustment (last_sp_set, memlist,
- last_sp_adjust + this_adjust,
- this_adjust))
- {
- /* It worked! */
- delete_insn (insn);
- last_sp_adjust += this_adjust;
- continue;
- }
- }
-
- /* Otherwise we have a deallocation. Do not combine with
- a previous allocation. Combine into the second insn. */
- else if (STACK_GROWS_DOWNWARD
- ? last_sp_adjust >= 0 : last_sp_adjust <= 0)
- {
- if (try_apply_stack_adjustment (insn, memlist,
- last_sp_adjust + this_adjust,
- -last_sp_adjust))
- {
- /* It worked! */
- delete_insn (last_sp_set);
- last_sp_set = insn;
- last_sp_adjust += this_adjust;
- free_csa_memlist (memlist);
- memlist = NULL;
- continue;
- }
- }
-
- /* Combination failed. Restart processing from here. If
- deallocation+allocation conspired to cancel, we can
- delete the old deallocation insn. */
- if (last_sp_set && last_sp_adjust == 0)
- delete_insn (insn);
- free_csa_memlist (memlist);
- memlist = NULL;
- last_sp_set = insn;
- last_sp_adjust = this_adjust;
- continue;
- }
-
- /* Find a predecrement of exactly the previous adjustment and
- turn it into a direct store. Obviously we can't do this if
- there were any intervening uses of the stack pointer. */
- if (memlist == NULL
- && GET_CODE (dest) == MEM
- && ((GET_CODE (XEXP (dest, 0)) == PRE_DEC
- && (last_sp_adjust
- == (HOST_WIDE_INT) GET_MODE_SIZE (GET_MODE (dest))))
- || (GET_CODE (XEXP (dest, 0)) == PRE_MODIFY
- && GET_CODE (XEXP (XEXP (dest, 0), 1)) == PLUS
- && XEXP (XEXP (XEXP (dest, 0), 1), 0) == stack_pointer_rtx
- && (GET_CODE (XEXP (XEXP (XEXP (dest, 0), 1), 1))
- == CONST_INT)
- && (INTVAL (XEXP (XEXP (XEXP (dest, 0), 1), 1))
- == -last_sp_adjust)))
- && XEXP (XEXP (dest, 0), 0) == stack_pointer_rtx
- && ! reg_mentioned_p (stack_pointer_rtx, src)
- && memory_address_p (GET_MODE (dest), stack_pointer_rtx)
- && validate_change (insn, &SET_DEST (set),
- replace_equiv_address (dest,
- stack_pointer_rtx),
- 0))
- {
- delete_insn (last_sp_set);
- free_csa_memlist (memlist);
- memlist = NULL;
- last_sp_set = NULL_RTX;
- last_sp_adjust = 0;
- continue;
- }
- }
-
- data.insn = insn;
- data.memlist = memlist;
- if (GET_CODE (insn) != CALL_INSN && last_sp_set
- && !for_each_rtx (&PATTERN (insn), record_stack_memrefs, &data))
- {
- memlist = data.memlist;
- continue;
- }
- memlist = data.memlist;
-
- /* Otherwise, we were not able to process the instruction.
- Do not continue collecting data across such a one. */
- if (last_sp_set
- && (GET_CODE (insn) == CALL_INSN
- || reg_mentioned_p (stack_pointer_rtx, PATTERN (insn))))
- {
- if (last_sp_set && last_sp_adjust == 0)
- delete_insn (last_sp_set);
- free_csa_memlist (memlist);
- memlist = NULL;
- last_sp_set = NULL_RTX;
- last_sp_adjust = 0;
- }
- }
-
- if (last_sp_set && last_sp_adjust == 0)
- delete_insn (last_sp_set);
-}
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