As discussed here: <https://gcc.gnu.org/ml/gcc-patches/2015-06/msg02223.html>.
Bootstrapped/regtested on x86_64-linux, applying to trunk.
2015-06-30 Marek Polacek <pola...@redhat.com>
* match.pd (~x | x): Don't use tree_nop_conversion_p. Build
the final expression with the operand's type and then convert
it to the type of the expression.
* gcc.dg/fold-ior-3.c: New test.
diff --git gcc/match.pd gcc/match.pd
index 682784b..adb7a52 100644
--- gcc/match.pd
+++ gcc/match.pd
@@ -286,8 +286,7 @@ along with GCC; see the file COPYING3. If not see
/* ~x | x -> -1 */
(simplify
(bit_ior:c (convert? @0) (convert? (bit_not @0)))
- (if (tree_nop_conversion_p (type, TREE_TYPE (@0)))
- { build_all_ones_cst (type); }))
+ (convert { build_all_ones_cst (TREE_TYPE (@0)); }))
/* x ^ x -> 0 */
(simplify
diff --git gcc/testsuite/gcc.dg/fold-ior-3.c gcc/testsuite/gcc.dg/fold-ior-3.c
index e69de29..ed89ff9 100644
--- gcc/testsuite/gcc.dg/fold-ior-3.c
+++ gcc/testsuite/gcc.dg/fold-ior-3.c
@@ -0,0 +1,35 @@
+/* { dg-do compile } */
+/* { dg-options "-O -fdump-tree-cddce1" } */
+
+int
+fn1 (_Bool a)
+{
+ return ((int) a) | ((int) ~a);
+}
+
+int
+fn2 (unsigned char a)
+{
+ return ((int) a) | ((int) ~a);
+}
+
+int
+fn3 (unsigned short a)
+{
+ return ((int) a) | ((int) ~a);
+}
+
+int
+fn4 (signed char a)
+{
+ return ((int) a) | ((int) ~a);
+}
+
+int
+fn5 (signed short a)
+{
+ return ((int) a) | ((int) ~a);
+}
+
+/* { dg-final { scan-tree-dump-not "~" "cddce1" } } */
+/* { dg-final { scan-tree-dump-not " \\| " "cddce1" } } */
Marek
