match.pd: Improve y == MIN || x < y optimization [PR105983]

On the following testcase, we only optimize bar where this optimization
is performed at GENERIC folding time, but on GIMPLE it doesn't trigger
anymore, as we actually don't see
  (bit_and (ne @1 min_value) (ge @0 @1))
but
  (bit_and (ne @1 min_value) (le @1 @0))
genmatch handles :c modifier not just on commutative operations, but
also comparisons and in that case it means it swaps the comparison.

2022-06-16  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/105983
	* match.pd (y == XXX_MIN || x < y -> x <= y - 1,
	y != XXX_MIN && x >= y -> x > y - 1): Use :cs instead of :s
	on non-equality comparisons.

	* gcc.dg/tree-ssa/pr105983.c: New test.

diff --git a/gcc/match.pd b/gcc/match.pd
index ae5dc820fa5d9ff9ea2a9b1a6c05d60070a47212..3e9572e4c9cbc276a374cffc9747a019ff824e0b 100644 (file)
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -2460,14 +2460,14 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
 
 /* y == XXX_MIN || x < y --> x <= y - 1 */
 (simplify
- (bit_ior:c (eq:s @1 min_value) (lt:s @0 @1))
+ (bit_ior:c (eq:s @1 min_value) (lt:cs @0 @1))
   (if (INTEGRAL_TYPE_P (TREE_TYPE (@1))
        && TYPE_OVERFLOW_WRAPS (TREE_TYPE (@1)))
   (le @0 (minus @1 { build_int_cst (TREE_TYPE (@1), 1); }))))
 
 /* y != XXX_MIN && x >= y --> x > y - 1 */
 (simplify
- (bit_and:c (ne:s @1 min_value) (ge:s @0 @1))
+ (bit_and:c (ne:s @1 min_value) (ge:cs @0 @1))
   (if (INTEGRAL_TYPE_P (TREE_TYPE (@1))
        && TYPE_OVERFLOW_WRAPS (TREE_TYPE (@1)))
   (gt @0 (minus @1 { build_int_cst (TREE_TYPE (@1), 1); }))))

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr105983.c b/gcc/testsuite/gcc.dg/tree-ssa/pr105983.c
new file mode 100644 (file)
index 0000000..46418c2
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr105983.c
@@ -0,0 +1,17 @@
+/* PR tree-optimization/105983 */
+/* { dg-do compile } */
+/* { dg-options "-O2 --param=logical-op-non-short-circuit=1 -fdump-tree-optimized" } */
+/* { dg-final { scan-tree-dump-not " != 0;" "optimized" } } */
+/* { dg-final { scan-tree-dump-not " & " "optimized" } } */
+
+int
+foo (unsigned a, unsigned b)
+{
+  return b != 0 && a >= b;
+}
+
+int
+bar (unsigned a, unsigned b)
+{
+  return b != 0 & a >= b;
+}