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* [PATCH] match.pd: Add new abs pattern [PR94290]
@ 2022-07-13 19:24 Sam Feifer
  2022-07-13 19:35 ` Andrew Pinski
  0 siblings, 1 reply; 11+ messages in thread
From: Sam Feifer @ 2022-07-13 19:24 UTC (permalink / raw)
  To: gcc-patches

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


^ permalink raw reply	[flat|nested] 11+ messages in thread

end of thread, other threads:[~2022-07-19 13:48 UTC | newest]

Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-07-13 19:24 [PATCH] match.pd: Add new abs pattern [PR94290] Sam Feifer
2022-07-13 19:35 ` Andrew Pinski
2022-07-14  6:52   ` Richard Biener
2022-07-14 14:09   ` Sam Feifer
2022-07-14 17:24     ` Andrew Pinski
2022-07-14 19:38       ` Sam Feifer
2022-07-14 19:53         ` Andrew Pinski
2022-07-18 13:07           ` Sam Feifer
2022-07-18 17:30             ` Sam Feifer
2022-07-19  6:36               ` Richard Biener
2022-07-19 13:48                 ` Sam Feifer

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