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combine.c (try_combine): Delay modifying of insns which cannot be easily undone.

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* combine.c (try_combine): Delay modifying of insns which cannot
        be easily undone.

From-SVN: r87025
This commit is contained in:
Roman Zippel 2004-09-03 04:12:12 +00:00 • committed by Richard Henderson
parent 6df9867e91
commit 9e42ab3e45
2 changed files with 44 additions and 34 deletions
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5
gcc/ChangeLog
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@ -1,3 +1,8 @@
2004-09-02 Roman Zippel <zippel@linux-m68k.org>
* combine.c (try_combine): Delay modifying of insns which cannot
be easily undone.
2004-09-02 Daniel Berlin <dberlin@dberlin.org>
* gcc/common.opt: Rename ivcanon to tree-loop-ivcanon, tree-lim to

73
gcc/combine.c
View file

@ -1602,6 +1602,7 @@ try_combine (rtx i3, rtx i2, rtx i1, int *new_direct_jump_p)
int i3_subst_into_i2 = 0;
/* Notes that I1, I2 or I3 is a MULT operation. */
int have_mult = 0;
int swap_i2i3 = 0;
int maxreg;
rtx temp;
@ -2468,40 +2469,7 @@ try_combine (rtx i3, rtx i2, rtx i1, int *new_direct_jump_p)
insn_code_number = recog_for_combine (&newpat, i3, &new_i3_notes);
if (insn_code_number >= 0)
{
rtx insn;
rtx link;
/* If we will be able to accept this, we have made a change to the
destination of I3. This requires us to do a few adjustments. */
PATTERN (i3) = newpat;
adjust_for_new_dest (i3);
/* I3 now uses what used to be its destination and which is
now I2's destination. That means we need a LOG_LINK from
I3 to I2. But we used to have one, so we still will.
However, some later insn might be using I2's dest and have
a LOG_LINK pointing at I3. We must remove this link.
The simplest way to remove the link is to point it at I1,
which we know will be a NOTE. */
for (insn = NEXT_INSN (i3);
insn && (this_basic_block->next_bb == EXIT_BLOCK_PTR
|| insn != BB_HEAD (this_basic_block->next_bb));
insn = NEXT_INSN (insn))
{
if (INSN_P (insn) && reg_referenced_p (ni2dest, PATTERN (insn)))
{
for (link = LOG_LINKS (insn); link;
link = XEXP (link, 1))
if (XEXP (link, 0) == i3)
XEXP (link, 0) = i1;
break;
}
}
}
swap_i2i3 = 1;
}
/* Similarly, check for a case where we have a PARALLEL of two independent
@ -2631,6 +2599,43 @@ try_combine (rtx i3, rtx i2, rtx i1, int *new_direct_jump_p)
/* We now know that we can do this combination. Merge the insns and
update the status of registers and LOG_LINKS. */
if (swap_i2i3)
{
rtx insn;
rtx link;
rtx ni2dest;
/* I3 now uses what used to be its destination and which is now
I2's destination. This requires us to do a few adjustments. */
PATTERN (i3) = newpat;
adjust_for_new_dest (i3);
/* We need a LOG_LINK from I3 to I2. But we used to have one,
so we still will.
However, some later insn might be using I2's dest and have
a LOG_LINK pointing at I3. We must remove this link.
The simplest way to remove the link is to point it at I1,
which we know will be a NOTE. */
ni2dest = SET_DEST (newi2pat);
for (insn = NEXT_INSN (i3);
insn && (this_basic_block->next_bb == EXIT_BLOCK_PTR
|| insn != BB_HEAD (this_basic_block->next_bb));
insn = NEXT_INSN (insn))
{
if (INSN_P (insn) && reg_referenced_p (ni2dest, PATTERN (insn)))
{
for (link = LOG_LINKS (insn); link;
link = XEXP (link, 1))
if (XEXP (link, 0) == i3)
XEXP (link, 0) = i1;
break;
}
}
}
{
rtx i3notes, i2notes, i1notes = 0;
rtx i3links, i2links, i1links = 0;