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rtlanal.c (single_set_1): Do not require USE and CLOBBERs to come last.

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* rtlanal.c (single_set_1): Do not require USE and CLOBBERs
	to come last.

From-SVN: r36699
This commit is contained in:
Jan Hubicka 2000-10-03 07:26:42 +00:00 committed by Jan Hubicka
parent 81bce466fe
commit c9b89a214a
2 changed files with 43 additions and 84 deletions
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5
gcc/ChangeLog
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@ -1,3 +1,8 @@
Mon Oct 2 14:50:14 MET DST 2000 Jan Hubicka <jh@suse.cz>
* rtlanal.c (single_set_1): Do not require USE and CLOBBERs
to come last.
2000-10-03 Michael Hayes <m.hayes@elec.canterbury.ac.nz>
* config/float-c4x.h: New.

122
gcc/rtlanal.c
View File

@ -846,98 +846,52 @@ rtx
single_set_1 (insn)
rtx insn;
{
rtx set;
rtx set = NULL;
int set_verified = 1;
rtx pat = PATTERN (insn);
int i;
if (GET_CODE (pat) == PARALLEL)
{
rtx x, sub;
/* This part is is performance critical for targets that use a lot of
parallels, such as i386. We want to accept as single set
instructions even an instructions with multiple sets where only
one has live result, but we attempt to delay this tests only for
multiple set instructions to reduce amount of calls to
find_reg_note and side_effects_p.
We expect the "common" instruction to be parallel with first SET
followed by the clobbers. So first we get the set, then look
if it is followed by USE or CLOBBER. If so, we just return expect
no SETs after these. When SET is followed by another SET, we
continue by the clomplex loop trought all members of PARALLEL.
*/
#ifdef ENABLE_CHECKING
if (XVECLEN (pat, 0) < 2)
abort ();
#endif
set = XVECEXP (pat, 0, 0);
switch (GET_CODE (set))
for (i = 0; i < XVECLEN (pat, 0); i++)
{
#ifdef ENABLE_CHECKING
case USE:
case CLOBBER:
/* Instruction should not consist only from USEs and CLOBBERS,
since then gcc is allowed to remove it entirely. In case
something else is present, it should be first in the pattern. */
fatal_insn ("USE or CLOBBER before SET:", insn);
#endif
case SET:
break;
default:
return NULL_RTX;
}
x = XVECEXP (pat, 0, 1);
switch (GET_CODE (x))
{
case USE:
case CLOBBER:
#ifdef ENABLE_CHECKING
/* The USEs and CLOBBERs should always come last in the pattern. */
for (i = XVECLEN (pat, 0) - 1; i > 1; i--)
if (GET_CODE (XVECEXP (pat, 0, i)) != USE
&& GET_CODE (XVECEXP (pat, 0, i)) != CLOBBER)
fatal_insn ("USE or CLOBBER before SET:", insn);
#endif
return set;
case SET:
{
int seen_clobber = 0;
rtx sub = XVECEXP (pat, 0, i);
switch (GET_CODE (sub))
{
case USE:
case CLOBBER:
break;
/* Multiple set insns - we are off the critical path now. */
for (i = 1; i < XVECLEN (pat, 0); i++)
{
sub = XVECEXP (pat, 0, i);
switch GET_CODE (sub)
{
case USE:
case CLOBBER:
seen_clobber = 1;
break;
case SET:
if (seen_clobber)
fatal_insn ("USE or CLOBBER before SET:", insn);
if (!set
|| (find_reg_note (insn, REG_UNUSED, SET_DEST (set))
&& side_effects_p (set)))
set = sub;
else if (! find_reg_note (insn, REG_UNUSED, SET_DEST (sub))
|| side_effects_p (sub))
return NULL_RTX;
break;
default:
return NULL_RTX;
}
}
}
return set;
default:
return NULL_RTX;
case SET:
/* We can consider insns having multiple sets, where all
but one are dead as single set insns. In common case
only single set is present in the pattern so we want
to avoid checking for REG_UNUSED notes unless neccesary.
When we reach set first time, we just expect this is
the single set we are looking for and only when more
sets are found in the insn, we check them. */
if (!set_verified)
{
if (find_reg_note (insn, REG_UNUSED, SET_DEST (set))
&& !side_effects_p (set))
set = NULL;
else
set_verified = 1;
}
if (!set)
set = sub, set_verified = 0;
else if (!find_reg_note (insn, REG_UNUSED, SET_DEST (sub))
|| side_effects_p (sub))
return NULL_RTX;
break;
default:
return NULL_RTX;
}
}
}
return 0;
return set;
}
/* Given an INSN, return nonzero if it has more than one SET, else return