x & C -> x if we know that x & ~C == 0

2016-05-17  Marc Glisse  <marc.glisse@inria.fr>

gcc/
	* match.pd (X & C): New transformation.

gcc/testsuite/
	* gcc.dg/tree-ssa/and-1.c: New testcase.

From-SVN: r236338

gcc/ChangeLog

 2016-05-17  Marc Glisse  <marc.glisse@inria.fr>
 
+	* match.pd (X & C): New transformation.
+
+2016-05-17  Marc Glisse  <marc.glisse@inria.fr>
+
 	* match.pd (~X & Y): New transformation.
 
 2016-05-17  Marc Glisse  <marc.glisse@inria.fr>

gcc/match.pd

@@ -563,6 +563,15 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
   (bitop @0 @0)
   (non_lvalue @0)))
 
+/* x & C -> x if we know that x & ~C == 0.  */
+#if GIMPLE
+(simplify
+ (bit_and SSA_NAME@0 INTEGER_CST@1)
+ (if (INTEGRAL_TYPE_P (TREE_TYPE (@0))
+      && (get_nonzero_bits (@0) & wi::bit_not (@1)) == 0)
+  @0))
+#endif
+
 /* x + (x & 1) -> (x + 1) & ~1 */
 (simplify
  (plus:c @0 (bit_and:s @0 integer_onep@1))

gcc/testsuite/ChangeLog

 2016-05-17  Marc Glisse  <marc.glisse@inria.fr>
 
+	* gcc.dg/tree-ssa/and-1.c: New testcase.
+
+2016-05-17  Marc Glisse  <marc.glisse@inria.fr>
+
 	* gcc.dg/tree-ssa/pr69270.c: Adjust.
 	* gcc.dg/tree-ssa/andnot-1.c: New testcase.
 

gcc/testsuite/gcc.dg/tree-ssa/and-1.c

+/* { dg-do compile } */
+/* { dg-options "-O -fdump-tree-optimized-raw" } */
+
+int f(int in) {
+  in = in | 3;
+  in = in ^ 1;
+  in = (in & ~(unsigned long)1);
+  return in;
+}
+
+/* { dg-final { scan-tree-dump-not "bit_and_expr" "optimized" } } */