For some reason it was missing.
Bootstrapped / tested on x86_64-unknown-linux-gnu, applied.
Richard.
2016-08-19 Richard Biener <rguent...@suse.de>
* match.pd (x | 0 -> x): Add.
Index: gcc/match.pd
===================================================================
--- gcc/match.pd (revision 239570)
+++ gcc/match.pd (working copy)
@@ -541,13 +541,18 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
/* x | ~0 -> ~0 */
(simplify
- (bit_ior @0 integer_all_onesp@1)
- @1)
+ (bit_ior @0 integer_all_onesp@1)
+ @1)
+
+/* x | 0 -> x */
+(simplify
+ (bit_ior @0 integer_zerop)
+ @0)
/* x & 0 -> 0 */
(simplify
- (bit_and @0 integer_zerop@1)
- @1)
+ (bit_and @0 integer_zerop@1)
+ @1)
/* ~x | x -> -1 */
/* ~x ^ x -> -1 */
