PR middle-end/23673

	* fold-const.c (fold_binary) <EQ_EXPR>:  Fold (X^Y) == 0 as X == Y
	and (X^Y) != 0 as X != Y.  Fold (X^Y) == Y as X == 0, and some
	symmetry related transformations.  Fold (X^C1) == C2 as
	X == (C1^C2).

	* gcc.dg/fold-eqxor-1.c: New test case.
	* gcc.dg/fold-eqxor-2.c: Likewise.
	* gcc.dg/fold-eqxor-3.c: Likewise.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@111442 138bc75d-0d04-0410-961f-82ee72b054a4

4 files changed, 91 insertions, 0 deletions

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 387e690134b..9656f4ee3ff 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,10 @@
+2006-02-25  Roger Sayle  <roger@eyesopen.com>
+
+	PR middle-end/23673
+	* gcc.dg/fold-eqxor-1.c: New test case.
+	* gcc.dg/fold-eqxor-2.c: Likewise.
+	* gcc.dg/fold-eqxor-3.c: Likewise.
+
 2006-02-25  Thomas Koenig  <Thomas.Koenig@online.de>
 
 	PR fortran/23092
diff --git a/gcc/testsuite/gcc.dg/fold-eqxor-1.c b/gcc/testsuite/gcc.dg/fold-eqxor-1.c
new file mode 100644
index 00000000000..d220e42bbfa
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/fold-eqxor-1.c
@@ -0,0 +1,28 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-original" } */
+
+int test1(int a, int b)
+{
+  return (a ^ b) == 0;
+}
+
+int test2(int c, int d)
+{
+  return (c ^ d) != 0;
+}
+
+unsigned int test3(unsigned int e, unsigned int f)
+{
+  return (e ^ f) == 0;
+}
+
+unsigned int test4(unsigned int g, unsigned int h)
+{
+  return (g ^ h) != 0;
+}
+
+/* { dg-final { scan-tree-dump-times "a == b" 1 "original" } } */
+/* { dg-final { scan-tree-dump-times "c != d" 1 "original" } } */
+/* { dg-final { scan-tree-dump-times "e == f" 1 "original" } } */
+/* { dg-final { scan-tree-dump-times "g != h" 1 "original" } } */
+/* { dg-final { cleanup-tree-dump "original" } } */
diff --git a/gcc/testsuite/gcc.dg/fold-eqxor-2.c b/gcc/testsuite/gcc.dg/fold-eqxor-2.c
new file mode 100644
index 00000000000..ee5ec9fa5ae
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/fold-eqxor-2.c
@@ -0,0 +1,28 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-original" } */
+
+int test1(int a, int b)
+{
+  return (a ^ b) == a;
+}
+
+int test2(int c, int d)
+{
+  return (c ^ d) != c;
+}
+
+int test3(int e, int f)
+{
+  return (e ^ f) == f;
+}
+
+int test4(int g, int h)
+{
+  return (g ^ h) != h;
+}
+
+/* { dg-final { scan-tree-dump-times "b == 0" 1 "original" } } */
+/* { dg-final { scan-tree-dump-times "d != 0" 1 "original" } } */
+/* { dg-final { scan-tree-dump-times "e == 0" 1 "original" } } */
+/* { dg-final { scan-tree-dump-times "g != 0" 1 "original" } } */
+/* { dg-final { cleanup-tree-dump "original" } } */
diff --git a/gcc/testsuite/gcc.dg/fold-eqxor-3.c b/gcc/testsuite/gcc.dg/fold-eqxor-3.c
new file mode 100644
index 00000000000..a087375aee9
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/fold-eqxor-3.c
@@ -0,0 +1,28 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-original" } */
+
+int test1(int a, int b)
+{
+  return (a ^ 2) == 2;
+}
+
+int test2(int c, int d)
+{
+  return (c ^ 4) != 4;
+}
+
+int test3(int e, int f)
+{
+  return (e ^ 2) == 6;
+}
+
+int test4(int g, int h)
+{
+  return (g ^ 6) != 4;
+}
+
+/* { dg-final { scan-tree-dump-times "a == 0" 1 "original" } } */
+/* { dg-final { scan-tree-dump-times "c != 0" 1 "original" } } */
+/* { dg-final { scan-tree-dump-times "e == 4" 1 "original" } } */
+/* { dg-final { scan-tree-dump-times "g != 2" 1 "original" } } */
+/* { dg-final { cleanup-tree-dump "original" } } */