===================================================================
@@ -2502,6 +2502,7 @@ try_combine (rtx i3, rtx i2, rtx i1, rtx
rtx i3dest_killed = 0;
/* SET_DEST and SET_SRC of I2, I1 and I0. */
rtx i2dest = 0, i2src = 0, i1dest = 0, i1src = 0, i0dest = 0, i0src = 0;
+ /* Copy of SET_SRC of I1, if needed. */
rtx i1src_copy = 0;
/* Set if I2DEST was reused as a scratch register. */
bool i2scratch = false;
@@ -3072,23 +3073,23 @@ try_combine (rtx i3, rtx i2, rtx i1, rtx
}
n_occurrences = 0; /* `subst' counts here */
-
- /* If I1 feeds into I2 and I1DEST is in I1SRC, we need to make a
- unique copy of I2SRC each time we substitute it to avoid
- self-referential rtl. */
-
subst_low_luid = DF_INSN_LUID (i2);
+
+ /* If I1 feeds into I2 and I1DEST is in I1SRC, we need to make a unique
+ copy of I2SRC each time we substitute it, in order to avoid creating
+ self-referential RTL when we will be substituting I1SRC for I1DEST
+ later. Likewise if I0 feeds into I2 and I0DEST is in I0SRC. */
newpat = subst (PATTERN (i3), i2dest, i2src, 0,
- ((i1_feeds_i2_n && i1dest_in_i1src)
- || (i0_feeds_i2_n && i0dest_in_i0src)));
+ (i1_feeds_i2_n && i1dest_in_i1src)
+ || (i0_feeds_i2_n && i0dest_in_i0src));
substed_i2 = 1;
- /* Record whether i2's body now appears within i3's body. */
+ /* Record whether I2's body now appears within I3's body. */
i2_is_used = n_occurrences;
}
- /* If we already got a failure, don't try to do more. Otherwise,
- try to substitute in I1 if we have it. */
+ /* If we already got a failure, don't try to do more. Otherwise, try to
+ substitute I1 if we have it. */
if (i1 && GET_CODE (newpat) != CLOBBER)
{
@@ -3099,10 +3100,10 @@ try_combine (rtx i3, rtx i2, rtx i1, rtx
&& i1_feeds_i2_n
&& dead_or_set_p (i2, i1dest)
&& !reg_overlap_mentioned_p (i1dest, newpat))
- /* Before we can do this substitution, we must redo the test done
- above (see detailed comments there) that ensures that I1DEST
- isn't mentioned in any SETs in NEWPAT that are field assignments. */
- || !combinable_i3pat (NULL_RTX, &newpat, i1dest, NULL_RTX, NULL_RTX,
+ /* Before we can do this substitution, we must redo the test done
+ above (see detailed comments there) that ensures I1DEST isn't
+ mentioned in any SETs in NEWPAT that are field assignments. */
+ || !combinable_i3pat (NULL_RTX, &newpat, i1dest, NULL_RTX, NULL_RTX,
0, 0, 0))
{
undo_all ();
@@ -3111,33 +3112,42 @@ try_combine (rtx i3, rtx i2, rtx i1, rtx
n_occurrences = 0;
subst_low_luid = DF_INSN_LUID (i1);
+
+ /* If I0 feeds into I1 and I0DEST is in I0SRC, we need to make a unique
+ copy of I1SRC each time we substitute it, in order to avoid creating
+ self-referential RTL when we will be substituting I0SRC for I0DEST
+ later. */
newpat = subst (newpat, i1dest, i1src, 0,
i0_feeds_i1_n && i0dest_in_i0src);
substed_i1 = 1;
+
+ /* Record whether I1's body now appears within I3's body. */
i1_is_used = n_occurrences;
}
+
+ /* Likewise for I0 if we have it. */
+
if (i0 && GET_CODE (newpat) != CLOBBER)
{
if ((FIND_REG_INC_NOTE (i0, NULL_RTX) != 0
&& ((i0_feeds_i2_n && dead_or_set_p (i2, i0dest))
|| (i0_feeds_i1_n && dead_or_set_p (i1, i0dest)))
&& !reg_overlap_mentioned_p (i0dest, newpat))
- || !combinable_i3pat (NULL_RTX, &newpat, i0dest, NULL_RTX, NULL_RTX,
+ || !combinable_i3pat (NULL_RTX, &newpat, i0dest, NULL_RTX, NULL_RTX,
0, 0, 0))
{
undo_all ();
return 0;
}
- /* Following subst may modify i1src, make a copy of it
- before it is for added_sets_2 handling if needed. */
+ /* If the following substitution will modify I1SRC, make a copy of it
+ for the case where it is substituted for I1DEST in I2PAT later. */
if (i0_feeds_i1_n && added_sets_2 && i1_feeds_i2_n)
i1src_copy = copy_rtx (i1src);
n_occurrences = 0;
subst_low_luid = DF_INSN_LUID (i0);
- newpat = subst (newpat, i0dest, i0src, 0,
- i0_feeds_i1_n && i0dest_in_i0src);
+ newpat = subst (newpat, i0dest, i0src, 0, 0);
substed_i0 = 1;
}
> Here is what I have committed after bootstrap/regtest. Thanks. Here's what I have installed on top of your patch, after retesting. 2010-11-03 Eric Botcazou <ebotcazou@adacore.com> * combine.c (try_combine): Fix formatting issues, improve comments and fix a pasto.