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combine.c (try_combine): Do not run subst on i1src and i2src in the case of generating a PARALLEL for a...

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* combine.c (try_combine): Do not run subst on i1src and i2src in
	the case of generating a PARALLEL for a comparison.

From-SVN: r107273
This commit is contained in:
Joseph Myers 2005-11-21 01:19:00 +00:00 • committed by Joseph Myers
parent d116ffa6c2
commit 7cf3d07976
2 changed files with 40 additions and 29 deletions
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5
gcc/ChangeLog
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@ -1,3 +1,8 @@
2005-11-20 Joseph S. Myers <joseph@codesourcery.com>
* combine.c (try_combine): Do not run subst on i1src and i2src in
the case of generating a PARALLEL for a comparison.
2005-11-20 Richard Henderson <rth@redhat.com>
PR 24931

64
gcc/combine.c
View file

@ -2080,35 +2080,6 @@ try_combine (rtx i3, rtx i2, rtx i1, int *new_direct_jump_p)
subst_insn = i3;
/* It is possible that the source of I2 or I1 may be performing an
unneeded operation, such as a ZERO_EXTEND of something that is known
to have the high part zero. Handle that case by letting subst look at
the innermost one of them.
Another way to do this would be to have a function that tries to
simplify a single insn instead of merging two or more insns. We don't
do this because of the potential of infinite loops and because
of the potential extra memory required. However, doing it the way
we are is a bit of a kludge and doesn't catch all cases.
But only do this if -fexpensive-optimizations since it slows things down
and doesn't usually win. */
if (flag_expensive_optimizations)
{
/* Pass pc_rtx so no substitutions are done, just simplifications. */
if (i1)
{
subst_low_cuid = INSN_CUID (i1);
i1src = subst (i1src, pc_rtx, pc_rtx, 0, 0);
}
else
{
subst_low_cuid = INSN_CUID (i2);
i2src = subst (i2src, pc_rtx, pc_rtx, 0, 0);
}
}
#ifndef HAVE_cc0
/* Many machines that don't use CC0 have insns that can both perform an
arithmetic operation and set the condition code. These operations will
@ -2171,6 +2142,41 @@ try_combine (rtx i3, rtx i2, rtx i1, int *new_direct_jump_p)
else
#endif
{
/* It is possible that the source of I2 or I1 may be performing
an unneeded operation, such as a ZERO_EXTEND of something
that is known to have the high part zero. Handle that case
by letting subst look at the innermost one of them.
Another way to do this would be to have a function that tries
to simplify a single insn instead of merging two or more
insns. We don't do this because of the potential of infinite
loops and because of the potential extra memory required.
However, doing it the way we are is a bit of a kludge and
doesn't catch all cases.
But only do this if -fexpensive-optimizations since it slows
things down and doesn't usually win.
This is not done in the COMPARE case above because the
unmodified I2PAT is used in the PARALLEL and so a pattern
with a modified I2SRC would not match. */
if (flag_expensive_optimizations)
{
/* Pass pc_rtx so no substitutions are done, just
simplifications. */
if (i1)
{
subst_low_cuid = INSN_CUID (i1);
i1src = subst (i1src, pc_rtx, pc_rtx, 0, 0);
}
else
{
subst_low_cuid = INSN_CUID (i2);
i2src = subst (i2src, pc_rtx, pc_rtx, 0, 0);
}
}
n_occurrences = 0; /* `subst' counts here */
/* If I1 feeds into I2 (not into I3) and I1DEST is in I1SRC, we