MATCH: Move `(x | y) & (~x ^ y)` over to use bitwise_inverted_equal_p

This moves the match pattern `(x | y) & (~x ^ y)` over to use bitwise_inverted_equal_p.
This now also allows to optmize comparisons and also catches the missed `(~x | y) & (x ^ y)`
transformation into `~x & y`.

OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.

gcc/ChangeLog:

	PR tree-optimization/111147
	* match.pd (`(x | y) & (~x ^ y)`) Use bitwise_inverted_equal_p
	instead of matching bit_not.

gcc/testsuite/ChangeLog:

	PR tree-optimization/111147
	* gcc.dg/tree-ssa/cmpbit-4.c: New test.

diff --git a/gcc/match.pd b/gcc/match.pd
index e6bdc3149b67427b3d88de4b830b15ec5dc5c87a..47d2733211a0c074e430b68cc21e85fbe9125a3b 100644 (file)
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -1616,8 +1616,11 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
 
 /* (x | y) & (~x ^ y) -> x & y */
 (simplify
- (bit_and:c (bit_ior:c @0 @1) (bit_xor:c @1 (bit_not @0)))
- (bit_and @0 @1))
+ (bit_and:c (bit_ior:c @0 @1) (bit_xor:c @1 @2))
+ (with { bool wascmp; }
+  (if (bitwise_inverted_equal_p (@0, @2, wascmp)
+       && (!wascmp || element_precision (type) == 1))
+   (bit_and @0 @1))))
 
 /* (~x | y) & (x | ~y) -> ~(x ^ y) */
 (simplify

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/cmpbit-4.c b/gcc/testsuite/gcc.dg/tree-ssa/cmpbit-4.c
new file mode 100644 (file)
index 0000000..cdba5d6
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/cmpbit-4.c
@@ -0,0 +1,47 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized-raw" } */
+
+int g(int x, int y)
+{
+  int xp = ~x;
+  return (x | y) & (xp ^ y); // x & y
+}
+int g0(int x, int y)
+{
+  int xp = ~x;
+  return (xp | y) & (x ^ y); // ~x & y
+}
+
+_Bool gb(_Bool x, _Bool y)
+{
+  _Bool xp = !x;
+  return (x | y) & (xp ^ y); // x & y
+}
+_Bool gb0(_Bool x, _Bool y)
+{
+  _Bool xp = !x;
+  return (xp | y) & (x ^ y); // !x & y
+}
+
+
+_Bool gbi(int a, int b)
+{
+  _Bool x = a < 2;
+  _Bool y = b < 3;
+  _Bool xp = !x;
+  return (x | y) & (xp ^ y); // x & y
+}
+_Bool gbi0(int a, int b)
+{
+  _Bool x = a < 2;
+  _Bool y = b < 3;
+  _Bool xp = !x;
+  return (xp | y) & (x ^ y); // !x & y
+}
+
+/* All of these should be optimized to `x & y` or `~x & y` */
+/* { dg-final { scan-tree-dump-times "le_expr, " 3 "optimized" } } */
+/* { dg-final { scan-tree-dump-times "gt_expr, " 1 "optimized" } } */
+/* { dg-final { scan-tree-dump-not "bit_xor_expr, " "optimized" } } */
+/* { dg-final { scan-tree-dump-times "bit_and_expr, " 6 "optimized" } } */
+/* { dg-final { scan-tree-dump-times "bit_not_expr, " 2 "optimized" } } */