Add a single pattern to reduce these patterns to "x ^ c":
x & c ? (x - c) | (x | c)
x & c ? (x & ~c) | (x | c)
As long as "c" has a single bit set.
PR 122615
PR 122616
gcc/ChangeLog:
* match.pd: New pattern.
gcc/testsuite/ChangeLog:
* gcc.dg/torture/pr122615.c: New test.
* gcc.dg/torture/pr122616.c: New test.
Co-authored-by: Jeff Law <[email protected]>
Signed-off-by: Daniel Barboza <[email protected]>
---
gcc/match.pd | 15 +++++++++++++++
gcc/testsuite/gcc.dg/torture/pr122615.c | 22 ++++++++++++++++++++++
gcc/testsuite/gcc.dg/torture/pr122616.c | 22 ++++++++++++++++++++++
3 files changed, 59 insertions(+)
create mode 100644 gcc/testsuite/gcc.dg/torture/pr122615.c
create mode 100644 gcc/testsuite/gcc.dg/torture/pr122616.c
diff --git a/gcc/match.pd b/gcc/match.pd
index 05c8b59eb9e..fbef7fd6e0f 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -6627,6 +6627,21 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(convert (minus { arg; } (convert:type1 @0))))))))))
#endif
+/* X & C1 ? (X + -C1) : (X | C1) -> X ^ C1
+ X & C1 ? (X & ~C1) : (X | C1) -> X ^ C1
+ when C1 has a single bit set. */
+(for op (plus bit_and)
+ (simplify
+ (cond (ne (bit_and @0 INTEGER_CST@1) integer_zerop)
+ (op @0 INTEGER_CST@2) (bit_ior @0 INTEGER_CST@1))
+ (with {
+ auto c1 = wi::to_wide (@1);
+ auto c2 = wi::to_wide (@2); }
+ (if (wi::popcount (c1) == 1
+ && ((op == PLUS_EXPR && wi::eq_p (wi::neg (c2), c1))
+ || (op == BIT_AND_EXPR && wi::eq_p (wi::bit_not (c2), c1))))
+ (bit_xor @0 @1)))))
+
(simplify
(convert (cond@0 @1 INTEGER_CST@2 INTEGER_CST@3))
(if (INTEGRAL_TYPE_P (type)
diff --git a/gcc/testsuite/gcc.dg/torture/pr122615.c
b/gcc/testsuite/gcc.dg/torture/pr122615.c
new file mode 100644
index 00000000000..9f4f3c49a01
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr122615.c
@@ -0,0 +1,22 @@
+/* { dg-do compile } */
+/* { dg-options "-fdump-tree-original" } */
+/* { dg-skip-if "" { *-*-* } { "-O0" } { "" } } */
+
+int f1 (int x)
+{
+ return x & 1 ? (x & ~1) : (x | 1);
+}
+
+int f2 (int x)
+{
+ return x & 2 ? (x & ~2) : (x | 2);
+}
+
+int f3 (int x)
+{
+ return x & 3 ? (x & ~3) : (x | 3);
+}
+
+/* { dg-final { scan-tree-dump-times "x \\^ 1" 1 "original" } } */
+/* { dg-final { scan-tree-dump-times "x \\^ 2" 1 "original" } } */
+/* { dg-final { scan-tree-dump-times "x \\^ 3" 0 "original" } } */
diff --git a/gcc/testsuite/gcc.dg/torture/pr122616.c
b/gcc/testsuite/gcc.dg/torture/pr122616.c
new file mode 100644
index 00000000000..77d364ef2f4
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr122616.c
@@ -0,0 +1,22 @@
+/* { dg-do compile } */
+/* { dg-options "-fdump-tree-original" } */
+/* { dg-skip-if "" { *-*-* } { "-O0" } { "" } } */
+
+int f1 (int x)
+{
+ return x & 1 ? (x - 1) : (x | 1);
+}
+
+int f2 (int x)
+{
+ return x & 2 ? (x - 2) : (x | 2);
+}
+
+int f3 (int x)
+{
+ return x & 3 ? (x - 3) : (x | 3);
+}
+
+/* { dg-final { scan-tree-dump-times "x \\^ 1" 1 "original" } } */
+/* { dg-final { scan-tree-dump-times "x \\^ 2" 1 "original" } } */
+/* { dg-final { scan-tree-dump-times "x \\^ 3" 0 "original" } } */
--
2.43.0
