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regmove.c: Update.

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* regmove.c: Update.
	* flags.h (flag_regmove): Declare.
	* rtl.h (optimize_reg_copy_1, optimize_reg_copy_2): Don't declare.
	* local-alloc.c (optimize_reg_copy_1, optimize_reg_copy_2):
	Moved into regmove; changed caller.
	* toplev.c (rest_of_compilation): Call regmove_optimize also for
	expensive_optimizations.

From-SVN: r17669
This commit is contained in:
J"orn Rennecke 1998-02-05 16:34:02 +00:00 committed by Joern Rennecke
parent b1ad0392e4
commit 1230327b00
6 changed files with 278 additions and 293 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
gcc/ChangeLog
View File

@ -1,3 +1,13 @@
Fri Feb 6 00:27:36 1998 J"orn Rennecke <amylaar@cygnus.co.uk>
* regmove.c: Update.
* flags.h (flag_regmove): Declare.
* rtl.h (optimize_reg_copy_1, optimize_reg_copy_2): Don't declare.
* local-alloc.c (optimize_reg_copy_1, optimize_reg_copy_2):
Moved into regmove; changed caller.
* toplev.c (rest_of_compilation): Call regmove_optimize also for
expensive_optimizations.
Thu Feb 5 13:38:42 PST 1998 Jeff Law (law@cygnus.com)
* version.c: Bump for snapshot.

3
gcc/flags.h
View File

@ -436,6 +436,9 @@ extern int flag_argument_noalias;
/* Emit code to check for stack overflow; also may cause large objects
to be allocated dynamically. */
extern int flag_stack_check;
/* Do the full regmove optimization pass. */
extern int flag_regmove;
/* Other basic status info about current function. */

279
gcc/local-alloc.c
View File

@ -739,268 +739,6 @@ memref_used_between_p (memref, start, end)
return 0;
}
/* INSN is a copy from SRC to DEST, both registers, and SRC does not die
in INSN.
Search forward to see if SRC dies before either it or DEST is modified,
but don't scan past the end of a basic block. If so, we can replace SRC
with DEST and let SRC die in INSN.
This will reduce the number of registers live in that range and may enable
DEST to be tied to SRC, thus often saving one register in addition to a
register-register copy. */
int
optimize_reg_copy_1 (insn, dest, src)
rtx insn;
rtx dest;
rtx src;
{
rtx p, q;
rtx note;
rtx dest_death = 0;
int sregno = REGNO (src);
int dregno = REGNO (dest);
if (sregno == dregno
/* We don't want to mess with hard regs if register classes are small. */
|| (SMALL_REGISTER_CLASSES
&& (sregno < FIRST_PSEUDO_REGISTER
|| dregno < FIRST_PSEUDO_REGISTER))
/* We don't see all updates to SP if they are in an auto-inc memory
reference, so we must disallow this optimization on them. */
|| sregno == STACK_POINTER_REGNUM || dregno == STACK_POINTER_REGNUM)
return 0;
for (p = NEXT_INSN (insn); p; p = NEXT_INSN (p))
{
if (GET_CODE (p) == CODE_LABEL || GET_CODE (p) == JUMP_INSN
|| (GET_CODE (p) == NOTE
&& (NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_BEG
|| NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_END)))
break;
if (GET_RTX_CLASS (GET_CODE (p)) != 'i')
continue;
if (reg_set_p (src, p) || reg_set_p (dest, p)
/* Don't change a USE of a register. */
|| (GET_CODE (PATTERN (p)) == USE
&& reg_overlap_mentioned_p (src, XEXP (PATTERN (p), 0))))
break;
/* See if all of SRC dies in P. This test is slightly more
conservative than it needs to be. */
if ((note = find_regno_note (p, REG_DEAD, sregno)) != 0
&& GET_MODE (XEXP (note, 0)) == GET_MODE (src))
{
int failed = 0;
int length = 0;
int d_length = 0;
int n_calls = 0;
int d_n_calls = 0;
/* We can do the optimization. Scan forward from INSN again,
replacing regs as we go. Set FAILED if a replacement can't
be done. In that case, we can't move the death note for SRC.
This should be rare. */
/* Set to stop at next insn. */
for (q = next_real_insn (insn);
q != next_real_insn (p);
q = next_real_insn (q))
{
if (reg_overlap_mentioned_p (src, PATTERN (q)))
{
/* If SRC is a hard register, we might miss some
overlapping registers with validate_replace_rtx,
so we would have to undo it. We can't if DEST is
present in the insn, so fail in that combination
of cases. */
if (sregno < FIRST_PSEUDO_REGISTER
&& reg_mentioned_p (dest, PATTERN (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))))
{
/* We assume that a register is used exactly once per
insn in the updates below. If this is not correct,
no great harm is done. */
if (sregno >= FIRST_PSEUDO_REGISTER)
REG_N_REFS (sregno) -= loop_depth;
if (dregno >= FIRST_PSEUDO_REGISTER)
REG_N_REFS (dregno) += loop_depth;
}
else
{
validate_replace_rtx (dest, src, q);
failed = 1;
}
}
/* Count the insns and CALL_INSNs passed. If we passed the
death note of DEST, show increased live length. */
length++;
if (dest_death)
d_length++;
/* 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)
{
n_calls++;
if (dest_death)
d_n_calls++;
}
/* If DEST dies here, remove the death note and save it for
later. Make sure ALL of DEST dies here; again, this is
overly conservative. */
if (dest_death == 0
&& (dest_death = find_regno_note (q, REG_DEAD, dregno)) != 0)
{
if (GET_MODE (XEXP (dest_death, 0)) != GET_MODE (dest))
failed = 1, dest_death = 0;
else
remove_note (q, dest_death);
}
}
if (! failed)
{
if (sregno >= FIRST_PSEUDO_REGISTER)
{
if (REG_LIVE_LENGTH (sregno) >= 0)
{
REG_LIVE_LENGTH (sregno) -= 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 (sregno) < 2)
REG_LIVE_LENGTH (sregno) = 2;
}
REG_N_CALLS_CROSSED (sregno) -= n_calls;
}
if (dregno >= FIRST_PSEUDO_REGISTER)
{
if (REG_LIVE_LENGTH (dregno) >= 0)
REG_LIVE_LENGTH (dregno) += d_length;
REG_N_CALLS_CROSSED (dregno) += d_n_calls;
}
/* Move death note of SRC from P to INSN. */
remove_note (p, note);
XEXP (note, 1) = REG_NOTES (insn);
REG_NOTES (insn) = note;
}
/* Put death note of DEST on P if we saw it die. */
if (dest_death)
{
XEXP (dest_death, 1) = REG_NOTES (p);
REG_NOTES (p) = dest_death;
}
return ! failed;
}
/* If SRC is a hard register which is set or killed in some other
way, we can't do this optimization. */
else if (sregno < FIRST_PSEUDO_REGISTER
&& dead_or_set_p (p, src))
break;
}
return 0;
}
/* INSN is a copy of SRC to DEST, in which SRC dies. See if we now have
a sequence of insns that modify DEST followed by an insn that sets
SRC to DEST in which DEST dies, with no prior modification of DEST.
(There is no need to check if the insns in between actually modify
DEST. We should not have cases where DEST is not modified, but
the optimization is safe if no such modification is detected.)
In that case, we can replace all uses of DEST, starting with INSN and
ending with the set of SRC to DEST, with SRC. We do not do this
optimization if a CALL_INSN is crossed unless SRC already crosses a
call or if DEST dies before the copy back to SRC.
It is assumed that DEST and SRC are pseudos; it is too complicated to do
this for hard registers since the substitutions we may make might fail. */
void
optimize_reg_copy_2 (insn, dest, src)
rtx insn;
rtx dest;
rtx src;
{
rtx p, q;
rtx set;
int sregno = REGNO (src);
int dregno = REGNO (dest);
for (p = NEXT_INSN (insn); p; p = NEXT_INSN (p))
{
if (GET_CODE (p) == CODE_LABEL || GET_CODE (p) == JUMP_INSN
|| (GET_CODE (p) == NOTE
&& (NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_BEG
|| NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_END)))
break;
if (GET_RTX_CLASS (GET_CODE (p)) != 'i')
continue;
set = single_set (p);
if (set && SET_SRC (set) == dest && SET_DEST (set) == src
&& find_reg_note (p, REG_DEAD, dest))
{
/* We can do the optimization. Scan forward from INSN again,
replacing regs as we go. */
/* Set to stop at next insn. */
for (q = insn; q != NEXT_INSN (p); q = NEXT_INSN (q))
if (GET_RTX_CLASS (GET_CODE (q)) == 'i')
{
if (reg_mentioned_p (dest, PATTERN (q)))
{
PATTERN (q) = replace_rtx (PATTERN (q), dest, src);
/* We assume that a register is used exactly once per
insn in the updates below. If this is not correct,
no great harm is done. */
REG_N_REFS (dregno) -= loop_depth;
REG_N_REFS (sregno) += loop_depth;
}
if (GET_CODE (q) == CALL_INSN)
{
REG_N_CALLS_CROSSED (dregno)--;
REG_N_CALLS_CROSSED (sregno)++;
}
}
remove_note (p, find_reg_note (p, REG_DEAD, dest));
REG_N_DEATHS (dregno)--;
remove_note (insn, find_reg_note (insn, REG_DEAD, src));
REG_N_DEATHS (sregno)--;
return;
}
if (reg_set_p (src, p)
|| find_reg_note (p, REG_DEAD, dest)
|| (GET_CODE (p) == CALL_INSN && REG_N_CALLS_CROSSED (sregno) == 0))
break;
}
}
/* Find registers that are equivalent to a single value throughout the
compilation (either because they can be referenced in memory or are set once
from a single constant). Lower their priority for a register.
@ -1085,22 +823,7 @@ update_equiv_regs ()
= gen_rtx_EXPR_LIST (REG_EQUIV, dest,
REG_NOTES (reg_equiv_init_insn[regno]));
/* If this is a register-register copy where SRC is not dead, see if we
can optimize it. */
if (flag_expensive_optimizations && GET_CODE (dest) == REG
&& GET_CODE (SET_SRC (set)) == REG
&& ! find_reg_note (insn, REG_DEAD, SET_SRC (set)))
optimize_reg_copy_1 (insn, dest, SET_SRC (set));
/* Similarly for a pseudo-pseudo copy when SRC is dead. */
else if (flag_expensive_optimizations && GET_CODE (dest) == REG
&& REGNO (dest) >= FIRST_PSEUDO_REGISTER
&& GET_CODE (SET_SRC (set)) == REG
&& REGNO (SET_SRC (set)) >= FIRST_PSEUDO_REGISTER
&& find_reg_note (insn, REG_DEAD, SET_SRC (set)))
optimize_reg_copy_2 (insn, dest, SET_SRC (set));
/* Otherwise, we only handle the case of a pseudo register being set
/* We only handle the case of a pseudo register being set
once and only if neither the source nor the destination are
in a register class that's likely to be spilled. */
if (GET_CODE (dest) != REG

273
gcc/regmove.c
View File

@ -44,18 +44,10 @@ the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
#include "expr.h"
#include "insn-flags.h"
#ifndef REG_N_CALLS_CROSSED
#define REG_N_CALLS_CROSSED(x) (reg_n_calls_crossed[(x)])
#define REG_N_SETS(x) (reg_n_sets[(x)])
#define REG_N_REFS(x) (reg_n_refs[(x)])
#define REG_N_DEATHS(x) (reg_n_deaths[(x)])
#define REG_LIVE_LENGTH(x) (reg_live_length[(x)])
#endif
static int optimize_reg_copy_1 PROTO((rtx, rtx, rtx));
static void optimize_reg_copy_2 PROTO((rtx, rtx, rtx));
static void optimize_reg_copy_3 PROTO((rtx, rtx, rtx));
extern int flag_regmove;
struct match {
int with[MAX_RECOG_OPERANDS];
enum { READ, WRITE, READWRITE } use[MAX_RECOG_OPERANDS];
@ -173,6 +165,267 @@ replacement_quality(reg)
return 2;
}
/* INSN is a copy from SRC to DEST, both registers, and SRC does not die
in INSN.
Search forward to see if SRC dies before either it or DEST is modified,
but don't scan past the end of a basic block. If so, we can replace SRC
with DEST and let SRC die in INSN.
This will reduce the number of registers live in that range and may enable
DEST to be tied to SRC, thus often saving one register in addition to a
register-register copy. */
static int
optimize_reg_copy_1 (insn, dest, src)
rtx insn;
rtx dest;
rtx src;
{
rtx p, q;
rtx note;
rtx dest_death = 0;
int sregno = REGNO (src);
int dregno = REGNO (dest);
/* We don't want to mess with hard regs if register classes are small. */
if (sregno == dregno
|| (SMALL_REGISTER_CLASSES
&& (sregno < FIRST_PSEUDO_REGISTER
|| dregno < FIRST_PSEUDO_REGISTER))
/* We don't see all updates to SP if they are in an auto-inc memory
reference, so we must disallow this optimization on them. */
|| sregno == STACK_POINTER_REGNUM || dregno == STACK_POINTER_REGNUM)
return 0;
for (p = NEXT_INSN (insn); p; p = NEXT_INSN (p))
{
if (GET_CODE (p) == CODE_LABEL || GET_CODE (p) == JUMP_INSN
|| (GET_CODE (p) == NOTE
&& (NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_BEG
|| NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_END)))
break;
if (GET_RTX_CLASS (GET_CODE (p)) != 'i')
continue;
if (reg_set_p (src, p) || reg_set_p (dest, p)
/* Don't change a USE of a register. */
|| (GET_CODE (PATTERN (p)) == USE
&& reg_overlap_mentioned_p (src, XEXP (PATTERN (p), 0))))
break;
/* See if all of SRC dies in P. This test is slightly more
conservative than it needs to be. */
if ((note = find_regno_note (p, REG_DEAD, sregno)) != 0
&& GET_MODE (XEXP (note, 0)) == GET_MODE (src))
{
int failed = 0;
int length = 0;
int d_length = 0;
int n_calls = 0;
int d_n_calls = 0;
/* We can do the optimization. Scan forward from INSN again,
replacing regs as we go. Set FAILED if a replacement can't
be done. In that case, we can't move the death note for SRC.
This should be rare. */
/* Set to stop at next insn. */
for (q = next_real_insn (insn);
q != next_real_insn (p);
q = next_real_insn (q))
{
if (reg_overlap_mentioned_p (src, PATTERN (q)))
{
/* If SRC is a hard register, we might miss some
overlapping registers with validate_replace_rtx,
so we would have to undo it. We can't if DEST is
present in the insn, so fail in that combination
of cases. */
if (sregno < FIRST_PSEUDO_REGISTER
&& reg_mentioned_p (dest, PATTERN (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))))
{
/* We assume that a register is used exactly once per
insn in the updates below. If this is not correct,
no great harm is done. */
if (sregno >= FIRST_PSEUDO_REGISTER)
REG_N_REFS (sregno) -= loop_depth;
if (dregno >= FIRST_PSEUDO_REGISTER)
REG_N_REFS (dregno) += loop_depth;
}
else
{
validate_replace_rtx (dest, src, q);
failed = 1;
}
}
/* Count the insns and CALL_INSNs passed. If we passed the
death note of DEST, show increased live length. */
length++;
if (dest_death)
d_length++;
/* 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)
{
n_calls++;
if (dest_death)
d_n_calls++;
}
/* If DEST dies here, remove the death note and save it for
later. Make sure ALL of DEST dies here; again, this is
overly conservative. */
if (dest_death == 0
&& (dest_death = find_regno_note (q, REG_DEAD, dregno)) != 0)
{
if (GET_MODE (XEXP (dest_death, 0)) != GET_MODE (dest))
failed = 1, dest_death = 0;
else
remove_note (q, dest_death);
}
}
if (! failed)
{
if (sregno >= FIRST_PSEUDO_REGISTER)
{
if (REG_LIVE_LENGTH (sregno) >= 0)
{
REG_LIVE_LENGTH (sregno) -= 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 (sregno) < 2)
REG_LIVE_LENGTH (sregno) = 2;
}
REG_N_CALLS_CROSSED (sregno) -= n_calls;
}
if (dregno >= FIRST_PSEUDO_REGISTER)
{
if (REG_LIVE_LENGTH (dregno) >= 0)
REG_LIVE_LENGTH (dregno) += d_length;
REG_N_CALLS_CROSSED (dregno) += d_n_calls;
}
/* Move death note of SRC from P to INSN. */
remove_note (p, note);
XEXP (note, 1) = REG_NOTES (insn);
REG_NOTES (insn) = note;
}
/* Put death note of DEST on P if we saw it die. */
if (dest_death)
{
XEXP (dest_death, 1) = REG_NOTES (p);
REG_NOTES (p) = dest_death;
}
return ! failed;
}
/* If SRC is a hard register which is set or killed in some other
way, we can't do this optimization. */
else if (sregno < FIRST_PSEUDO_REGISTER
&& dead_or_set_p (p, src))
break;
}
return 0;
}
/* INSN is a copy of SRC to DEST, in which SRC dies. See if we now have
a sequence of insns that modify DEST followed by an insn that sets
SRC to DEST in which DEST dies, with no prior modification of DEST.
(There is no need to check if the insns in between actually modify
DEST. We should not have cases where DEST is not modified, but
the optimization is safe if no such modification is detected.)
In that case, we can replace all uses of DEST, starting with INSN and
ending with the set of SRC to DEST, with SRC. We do not do this
optimization if a CALL_INSN is crossed unless SRC already crosses a
call or if DEST dies before the copy back to SRC.
It is assumed that DEST and SRC are pseudos; it is too complicated to do
this for hard registers since the substitutions we may make might fail. */
static void
optimize_reg_copy_2 (insn, dest, src)
rtx insn;
rtx dest;
rtx src;
{
rtx p, q;
rtx set;
int sregno = REGNO (src);
int dregno = REGNO (dest);
for (p = NEXT_INSN (insn); p; p = NEXT_INSN (p))
{
if (GET_CODE (p) == CODE_LABEL || GET_CODE (p) == JUMP_INSN
|| (GET_CODE (p) == NOTE
&& (NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_BEG
|| NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_END)))
break;
if (GET_RTX_CLASS (GET_CODE (p)) != 'i')
continue;
set = single_set (p);
if (set && SET_SRC (set) == dest && SET_DEST (set) == src
&& find_reg_note (p, REG_DEAD, dest))
{
/* We can do the optimization. Scan forward from INSN again,
replacing regs as we go. */
/* Set to stop at next insn. */
for (q = insn; q != NEXT_INSN (p); q = NEXT_INSN (q))
if (GET_RTX_CLASS (GET_CODE (q)) == 'i')
{
if (reg_mentioned_p (dest, PATTERN (q)))
{
PATTERN (q) = replace_rtx (PATTERN (q), dest, src);
/* We assume that a register is used exactly once per
insn in the updates below. If this is not correct,
no great harm is done. */
REG_N_REFS (dregno) -= loop_depth;
REG_N_REFS (sregno) += loop_depth;
}
if (GET_CODE (q) == CALL_INSN)
{
REG_N_CALLS_CROSSED (dregno)--;
REG_N_CALLS_CROSSED (sregno)++;
}
}
remove_note (p, find_reg_note (p, REG_DEAD, dest));
REG_N_DEATHS (dregno)--;
remove_note (insn, find_reg_note (insn, REG_DEAD, src));
REG_N_DEATHS (sregno)--;
return;
}
if (reg_set_p (src, p)
|| find_reg_note (p, REG_DEAD, dest)
|| (GET_CODE (p) == CALL_INSN && 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 encorporate the zero/sign extension

4
gcc/rtl.h
View File

@ -1373,8 +1373,4 @@ extern void init_alias_once PROTO ((void));
extern void init_alias_analysis PROTO ((void));
extern void end_alias_analysis PROTO ((void));
/* In local-alloc.c */
extern int optimize_reg_copy_1 PROTO((rtx, rtx, rtx));
extern void optimize_reg_copy_2 PROTO((rtx, rtx, rtx));
#endif /* _RTL_H */

2
gcc/toplev.c
View File

@ -3408,7 +3408,7 @@ rest_of_compilation (decl)
/* Register allocation pre-pass, to reduce number of moves
necessary for two-address machines. */
if (optimize > 0 && flag_regmove)
if (optimize > 0 && (flag_regmove || flag_expensive_optimizations))
{
if (regmove_dump)
open_dump_file (".regmove", decl_printable_name (decl, 2));