This patch is intended to fix a missed optimization in match.pd. It optimizes
(x >= 0 ? x : 0) + (x <= 0 ? -x : 0) to just abs(x). I had to write a second
simplification in match.pd to handle the commutative property as the match was
not ocurring otherwise. Additionally, the pattern (x <= 0 ? -x : 0) now gets
optimized to max(-x, 0), which helps with the other simplification rule.
Tests are also included to be added to the testsuite.
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
PR tree-optimization/94290
gcc/ChangeLog:
* match.pd (x >= 0 ? x : 0) + (x <= 0 ? -x : 0): New simplification.
* match.pd (x <= 0 ? -x : 0): New Simplification.
gcc/testsuite/ChangeLog:
* gcc.c-torture/execute/pr94290-1.c: New test.
* gcc.dg/pr94290-2.c: New test.
* gcc.dg/pr94290.c: New test.
---
gcc/match.pd | 15 ++++++
.../gcc.c-torture/execute/pr94290-1.c | 16 +++++++
gcc/testsuite/gcc.dg/pr94290-2.c | 15 ++++++
gcc/testsuite/gcc.dg/pr94290.c | 46 +++++++++++++++++++
4 files changed, 92 insertions(+)
create mode 100644 gcc/testsuite/gcc.c-torture/execute/pr94290-1.c
create mode 100644 gcc/testsuite/gcc.dg/pr94290-2.c
create mode 100644 gcc/testsuite/gcc.dg/pr94290.c
diff --git a/gcc/match.pd b/gcc/match.pd
index 45aefd96688..55ca79d7ac9 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -7848,3 +7848,18 @@ and,
(if (TYPE_UNSIGNED (TREE_TYPE (@0)))
(bit_and @0 @1)
(cond (le @0 @1) @0 (bit_and @0 @1))))))
+
+/* (x >= 0 ? x : 0) + (x <= 0 ? -x : 0) -> abs x. */
+(simplify
+ (plus (max @0 integer_zerop) (max (negate @0) integer_zerop))
+ (abs @0))
+
+/* (x <= 0 ? -x : 0) + (x >= 0 ? x : 0) -> abs x. */
+(simplify
+ (plus (max (negate @0) integer_zerop) (max @0 integer_zerop) )
+ (abs @0))
+
+/* (x <= 0 ? -x : 0) -> max(-x, 0). */
+(simplify
+ (cond (le @0 integer_zerop@1) (negate @0) integer_zerop@1)
+ (max (negate @0) @1))
diff --git a/gcc/testsuite/gcc.c-torture/execute/pr94290-1.c
b/gcc/testsuite/gcc.c-torture/execute/pr94290-1.c
new file mode 100644
index 00000000000..93b80d569aa
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr94290-1.c
@@ -0,0 +1,16 @@
+/* PR tree-optimization/94290 */
+
+#include "../../gcc.dg/pr94290.c"
+
+int main() {
+
+ if (foo(0) != 0
+ || foo(-42) != 42
+ || foo(42) != 42
+ || baz(-10) != 10
+ || baz(-10) != 10) {
+ __builtin_abort();
+ }
+
+ return 0;
+}
diff --git a/gcc/testsuite/gcc.dg/pr94290-2.c b/gcc/testsuite/gcc.dg/pr94290-2.c
new file mode 100644
index 00000000000..ea6e55755f5
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr94290-2.c
@@ -0,0 +1,15 @@
+/* PR tree-optimization/94290 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+/* Form from PR. */
+__attribute__((noipa)) unsigned int foo(int x) {
+ return x <= 0 ? -x : 0;
+}
+
+/* Changed order. */
+__attribute__((noipa)) unsigned int bar(int x) {
+ return 0 >= x ? -x : 0;
+}
+
+/* { dg-final {scan-tree-dump-times " MAX_EXPR " 2 "optimized" } } */
diff --git a/gcc/testsuite/gcc.dg/pr94290.c b/gcc/testsuite/gcc.dg/pr94290.c
new file mode 100644
index 00000000000..47617c36c02
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr94290.c
@@ -0,0 +1,46 @@
+/* PR tree-optimization/94290 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+
+/* Same form as PR. */
+__attribute__((noipa)) unsigned int foo(int x) {
+ return (x >= 0 ? x : 0) + (x <= 0 ? -x : 0);
+}
+
+/* Signed function. */
+__attribute__((noipa)) int bar(int x) {
+ return (x >= 0 ? x : 0) + (x <= 0 ? -x : 0);
+}
+
+/* Commutative property. */
+__attribute__((noipa)) unsigned int baz(int x) {
+ return (x <= 0 ? -x : 0) + (x >= 0 ? x : 0);
+}
+
+/* Flipped order for max expressions. */
+__attribute__((noipa)) unsigned int quux(int x) {
+ return (0 <= x ? x : 0) + (0 >= x ? -x : 0);
+}
+
+/* Not zero so should not optimize. */
+__attribute__((noipa)) unsigned int waldo(int x) {
+ return (x >= 4 ? x : 4) + (x <= 4 ? -x : 4);
+}
+
+/* Not zero so should not optimize. */
+__attribute__((noipa)) unsigned int fred(int x) {
+ return (x >= -4 ? x : -4) + (x <= -4 ? -x : -4);
+}
+
+/* Incorrect pattern. */
+__attribute__((noipa)) unsigned int goo(int x) {
+ return (x <= 0 ? x : 0) + (x >= 0 ? -x : 0);
+}
+
+/* Incorrect pattern. */
+__attribute__((noipa)) int qux(int x) {
+ return (x >= 0 ? x : 0) + (x >= 0 ? x : 0);
+}
+
+/* { dg-final {scan-tree-dump-times " ABS_EXPR " 4 "optimized" } } */
base-commit: 6af530f914801f5e561057da55c41480f28751f7
--
2.31.1
