re PR tree-optimization/53979 (((a ^ b) | a) not optimized to (a | b))

2016-10-20  Prathamesh Kulkarni  <prathamesh.kulkarni@linaro.org>

	PR tree-optimization/53979
	* match.pd ((a ^ b) | a -> a | b): New pattern.

testsuite/
	* gcc.dg/pr53979-1.c: New test-case.
	* gcc.dg/pr53979-2.c: Likewise.

From-SVN: r241360

gcc/ChangeLog

+2016-10-20  Prathamesh Kulkarni  <prathamesh.kulkarni@linaro.org>
+
+	PR tree-optimization/53979
+	* match.pd ((a ^ b) | a -> a | b): New pattern.
+
 2016-10-19  John David Anglin  <danglin@gcc.gnu.org>
 
 	* config/pa/pa64-hpux.h (PA_INIT_FRAME_DUMMY_ASM_OP): Move to

gcc/match.pd

@@ -541,6 +541,12 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
  (bit_ior:c (bit_and @0 INTEGER_CST@2) (bit_and (bit_not @0) INTEGER_CST@1))
  (if (wi::bit_not (@2) == @1)
   (bit_xor @0 @1)))
+
+/* PR53979: Transform ((a ^ b) | a) -> (a | b) */
+(simplify
+  (bit_ior:c (bit_xor:c @0 @1) @0)
+  (bit_ior @0 @1))
+
 /* Simplify (~X & Y) to X ^ Y if we know that (X & ~Y) is 0.  */
 #if GIMPLE
 (simplify

gcc/testsuite/ChangeLog

+2016-10-20  Prathamesh Kulkarni  <prathamesh.kulkarni@linaro.org>
+
+	PR tree-optimization/53979
+	* gcc.dg/pr53979-1.c: New test-case.
+	* gcc.dg/pr53979-2.c: Likewise.
+
 2016-10-19  Bernd Edlinger  <bernd.edlinger@hotmail.de>
 
 	* c-c++-common/Wint-in-bool-context-2.c: New test.

gcc/testsuite/gcc.dg/pr53979-1.c

+/* { dg-do compile } */
+/* { dg-options "-fdump-tree-gimple" } */
+
+unsigned f1(unsigned a, unsigned b)
+{
+  return (a ^ b) | a; 
+}
+
+/* { dg-final { scan-tree-dump "a | b" "gimple" } } */

gcc/testsuite/gcc.dg/pr53979-2.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-forwprop-details" } */
+
+unsigned f(unsigned a, unsigned b)
+{
+  unsigned t1 = a ^ b;
+  unsigned t2 = t1 | a;
+  return t2;
+}
+
+/* { dg-final { scan-tree-dump "gimple_simplified to t2_\[0-9\] = a_\[0-9\]*\\(D\\) | b_\[0-9\]*\\(D\\)" "forwprop1" } } */