Hi!
The fix for this PR didn't come with any test coverage, I've added
tests that make sure we optimize it no matter what order of the x ^ y ^ z
operands is used.
Bootstrapped/regtested on x86_64-linux and i686-linux, committed to trunk.
2021-01-15 Jakub Jelinek <ja...@redhat.com>
PR tree-optimization/96671
* gcc.dg/tree-ssa/pr96671-1.c: New test.
* gcc.dg/tree-ssa/pr96671-2.c: New test.
--- gcc/testsuite/gcc.dg/tree-ssa/pr96671-1.c.jj 2021-01-15
14:44:54.694936995 +0100
+++ gcc/testsuite/gcc.dg/tree-ssa/pr96671-1.c 2021-01-15 14:45:40.248419337
+0100
@@ -0,0 +1,51 @@
+/* PR tree-optimization/96671 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+/* { dg-final { scan-tree-dump-times " \\^ " 6 "optimized" } } */
+/* { dg-final { scan-tree-dump-times " ~" 6 "optimized" } } */
+/* { dg-final { scan-tree-dump-times " & " 6 "optimized" } } */
+
+int
+foo (int a, int b, int c)
+{
+ return (a ^ b) & ((b ^ c) ^ a);
+}
+
+int
+bar (int a, int b, int c)
+{
+ return (a ^ b) & ((b ^ a) ^ c);
+}
+
+int
+baz (int a, int b, int c)
+{
+ return (a ^ b) & ((a ^ c) ^ b);
+}
+
+int
+qux (int a, int b, int c)
+{
+ int d = a ^ b;
+ int e = b ^ c;
+ int f = e ^ a;
+ return d & f;
+}
+
+int
+corge (int a, int b, int c)
+{
+ int d = a ^ b;
+ int e = b ^ a;
+ int f = c ^ e;
+ return d & f;
+}
+
+int
+garply (int a, int b, int c)
+{
+ int d = a ^ b;
+ int e = a ^ c;
+ int f = b ^ e;
+ return d & f;
+}
--- gcc/testsuite/gcc.dg/tree-ssa/pr96671-2.c.jj 2021-01-15
14:44:57.665903235 +0100
+++ gcc/testsuite/gcc.dg/tree-ssa/pr96671-2.c 2021-01-15 14:45:49.565313469
+0100
@@ -0,0 +1,51 @@
+/* PR tree-optimization/96671 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+/* { dg-final { scan-tree-dump-times " \\^ " 6 "optimized" } } */
+/* { dg-final { scan-tree-dump-not " ~" "optimized" } } */
+/* { dg-final { scan-tree-dump-times " \\| " 6 "optimized" } } */
+
+int
+foo (int a, int b, int c)
+{
+ return (a ^ b) | ((b ^ c) ^ a);
+}
+
+int
+bar (int a, int b, int c)
+{
+ return (a ^ b) | ((b ^ a) ^ c);
+}
+
+int
+baz (int a, int b, int c)
+{
+ return (a ^ b) | ((a ^ c) ^ b);
+}
+
+int
+qux (int a, int b, int c)
+{
+ int d = a ^ b;
+ int e = b ^ c;
+ int f = e ^ a;
+ return d | f;
+}
+
+int
+corge (int a, int b, int c)
+{
+ int d = a ^ b;
+ int e = b ^ a;
+ int f = c ^ e;
+ return d | f;
+}
+
+int
+garply (int a, int b, int c)
+{
+ int d = a ^ b;
+ int e = a ^ c;
+ int f = b ^ e;
+ return d | f;
+}
Jakub
