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[PATCH] Fix cc_use tweaks in combiner (PR rtl-optimization/38774)
- From: Jakub Jelinek <jakub at redhat dot com>
- To: gcc-patches at gcc dot gnu dot org
- Date: Tue, 13 Jan 2009 23:29:42 +0100
- Subject: [PATCH] Fix cc_use tweaks in combiner (PR rtl-optimization/38774)
- Reply-to: Jakub Jelinek <jakub at redhat dot com>
Hi!
When simplify_set contemplates changing the CC using comparison in
*cc_use, but then decides not to do that, *cc_use remains the newly
created comparison, but with the old code, i.e. it is rtx_equal_p
with the old one, but not the same pointer. As in this case the
other insn possibly won't have df_rescan_insn called on it, this
confuses df.
Fixed by restoring the old rtx pointer instead.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2009-01-13 Jakub Jelinek <jakub@redhat.com>
PR rtl-optimization/38774
* combine.c (simplify_set): When undoing cc_use change, don't do
PUT_CODE on the newly created comparison, but instead put back the
old comparison.
* gcc.dg/torture/pr38774.c: New test.
--- gcc/combine.c.jj 2009-01-13 18:32:17.000000000 +0100
+++ gcc/combine.c 2009-01-13 21:50:41.000000000 +0100
@@ -5706,6 +5706,7 @@ simplify_set (rtx x)
{
int other_changed_previously = other_changed;
unsigned HOST_WIDE_INT mask;
+ rtx old_cc_use = *cc_use;
SUBST (*cc_use, gen_rtx_fmt_ee (new_code, GET_MODE (*cc_use),
dest, const0_rtx));
@@ -5728,7 +5729,7 @@ simplify_set (rtx x)
if ((recog_for_combine (&pat, other_insn, ¬e) < 0
&& ! check_asm_operands (pat)))
{
- PUT_CODE (*cc_use, old_code);
+ *cc_use = old_cc_use;
other_changed = 0;
op0 = simplify_gen_binary (XOR, GET_MODE (op0),
--- gcc/testsuite/gcc.dg/torture/pr38774.c.jj 2009-01-13 21:53:10.000000000 +0100
+++ gcc/testsuite/gcc.dg/torture/pr38774.c 2009-01-13 21:53:01.000000000 +0100
@@ -0,0 +1,16 @@
+/* PR rtl-optimization/38774 */
+/* { dg-do compile } */
+/* { dg-options "" } */
+/* { dg-options "-march=i686" { target { { i?86-*-* x86_64-*-* } && ilp32 } } } */
+
+extern int bar (void);
+volatile int g;
+
+int
+foo (void)
+{
+ int a = 1 >= bar ();
+ if ((1 > 9223372036854775807LL - a && 1 - a ? : 1 + a) & 1)
+ return g;
+ return 0;
+}
Jakub