This patch adds a new optimization to match.pd. The pattern, -x & 1,
now gets simplified to x & 1, reducing the number of instructions
produced.
This patch also adds tests for the optimization rule.
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
PR tree-optimization/106243
gcc/ChangeLog:
* match.pd (-x & 1): New simplification.
gcc/testsuite/ChangeLog:
* gcc.dg/pr106243-1.c: New test.
* gcc.dg/pr106243.c: New test.
---
gcc/match.pd | 5 ++++
gcc/testsuite/gcc.dg/pr106243-1.c | 18 +++++++++++++
gcc/testsuite/gcc.dg/pr106243.c | 43 +++++++++++++++++++++++++++++++
3 files changed, 66 insertions(+)
create mode 100644 gcc/testsuite/gcc.dg/pr106243-1.c
create mode 100644 gcc/testsuite/gcc.dg/pr106243.c
diff --git a/gcc/match.pd b/gcc/match.pd
index 562138a8034..78b32567836 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -8061,3 +8061,8 @@ and,
(if (TYPE_UNSIGNED (TREE_TYPE (@0)))
(bit_and @0 @1)
(cond (le @0 @1) @0 (bit_and @0 @1))))))
+
+/* -x & 1 -> x & 1. */
+(simplify
+ (bit_and:c (negate @0) integer_onep@1)
+ (bit_and @0 @1))
diff --git a/gcc/testsuite/gcc.dg/pr106243-1.c
b/gcc/testsuite/gcc.dg/pr106243-1.c
new file mode 100644
index 00000000000..b1dbe5cbe44
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr106243-1.c
@@ -0,0 +1,18 @@
+/* PR tree-optimization/106243 */
+/* { dg-do run } */
+/* { dg-options "-O2" } */
+
+#include "pr106243.c"
+
+int main () {
+
+ if (foo(3) != 1
+ || bar(-6) != 0
+ || baz(17) != 1
+ || qux(-128) != 0
+ || foo(127) != 1) {
+ __builtin_abort();
+ }
+
+ return 0;
+}
diff --git a/gcc/testsuite/gcc.dg/pr106243.c b/gcc/testsuite/gcc.dg/pr106243.c
new file mode 100644
index 00000000000..ee2706f2bf9
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr106243.c
@@ -0,0 +1,43 @@
+/* PR tree-optimization/106243 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+#define vector __attribute__((vector_size(4*sizeof(int))))
+
+/* Test from PR. */
+__attribute__((noipa)) int foo (int x) {
+ return -x & 1;
+}
+
+/* Other test from PR. */
+__attribute__((noipa)) int bar (int x) {
+ return (0 - x) & 1;
+}
+
+/* Forward propogation. */
+__attribute__((noipa)) int baz (int x) {
+ x = -x;
+ return x & 1;
+}
+
+/* Commutative property. */
+__attribute__((noipa)) int qux (int x) {
+ return 1 & -x;
+}
+
+/* Vector test case. */
+__attribute__((noipa)) vector int waldo (vector int x) {
+ return -x & 1;
+}
+
+/* Should not simplify. */
+__attribute__((noipa)) int thud (int x) {
+ return -x & 2;
+}
+
+/* Should not simplify. */
+__attribute__((noipa)) int corge (int x) {
+ return -x & -1;
+}
+
+/* { dg-final {scan-tree-dump-times "-" 2 "optimized" } } */
base-commit: 388fbbd895e72669909173c3003ae65c6483a3c2
--
2.31.1
