This patch adds a simplification to match.pd that was discussed on the
thread for pr106243. It simplifies the pattern, abs(x) & 1, to x & 1.
There are also tests for the simplification in this patch. I couldn't
figure out how to get abs to work with vectors. If a test for that is
necessary, could I get some guidance on using abs with vector types?
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
PR tree-optimization/106243
gcc/ChangeLog:
* match.pd (abs(x) & 1): New simplification.
gcc/testsuite/ChangeLog:
* gcc.dg/pr106243-2.c: New test.
* gcc.dg/pr106243-3.c: New test.
---
gcc/match.pd | 5 +++++
gcc/testsuite/gcc.dg/pr106243-2.c | 31 +++++++++++++++++++++++++++++++
gcc/testsuite/gcc.dg/pr106243-3.c | 18 ++++++++++++++++++
3 files changed, 54 insertions(+)
create mode 100644 gcc/testsuite/gcc.dg/pr106243-2.c
create mode 100644 gcc/testsuite/gcc.dg/pr106243-3.c
diff --git a/gcc/match.pd b/gcc/match.pd
index f82f94ad1fe..c04e70f34c1 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -8071,3 +8071,8 @@ and,
(simplify
(bit_and (negate @0) integer_onep@1)
(bit_and @0 @1))
+
+/* abs(x) & 1 -> x & 1. */
+(simplify
+ (bit_and (abs @0) integer_onep@1)
+ (bit_and @0 @1))
diff --git a/gcc/testsuite/gcc.dg/pr106243-2.c
b/gcc/testsuite/gcc.dg/pr106243-2.c
new file mode 100644
index 00000000000..27e66f59160
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr106243-2.c
@@ -0,0 +1,31 @@
+/* PR tree-optimization/106243 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+#include <stdlib.h>
+
+__attribute__((noipa)) int foo (int x) {
+ return abs(x) & 1;
+}
+
+__attribute__((noipa)) int bar (int x) {
+ return (0 - abs(x)) & 1;
+}
+
+/* Commutative property. */
+__attribute__((noipa)) int baz (int x) {
+ return 1 & abs(x);
+}
+
+/* Forward propogation. */
+__attribute__((noipa)) int qux (int x) {
+ int y = abs(x);
+ return y & 1;
+}
+
+/* Should not simplify. */
+__attribute__((noipa)) int thud (int x) {
+ return abs(x) & -1;
+}
+
+/* { dg-final {scan-tree-dump-times " ABS_EXPR " 1 "optimized" } } */
diff --git a/gcc/testsuite/gcc.dg/pr106243-3.c
b/gcc/testsuite/gcc.dg/pr106243-3.c
new file mode 100644
index 00000000000..68800868751
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr106243-3.c
@@ -0,0 +1,18 @@
+/* PR tree-optimization/106243 */
+/* { dg-do run } */
+/* { dg-options "-O2" } */
+
+#include "pr106243-2.c"
+
+int main () {
+
+ if (foo(6) != 0
+ || bar(-3) != 1
+ || baz(32) != 0
+ || qux(-128) != 0
+ || foo (127) != 1) {
+ __builtin_abort();
+ }
+
+ return 0;
+}
base-commit: be58bf98e98bb431ed26ca8be84586075fe8be82
--
2.31.1
