This moves a simple optimization. Here it's plain to see how :c
removes the need to duplicate code to handle commutativity.
I put some more converts into the pattern, but then it's turned
out that I also need the tree_nop_conversion_p (otherwise we'd
regress binop-notor2.c that uses booleans).
I did a regtest with the patterns in fold-const.c removed to see
whether we have some testing for this folding -- and there were
no regressions, so I had to write a test.
Bootstrapped/regtested on x86_64-linux, ok for trunk?
2015-06-29 Marek Polacek <pola...@redhat.com>
* fold-const.c (fold_binary_loc): Move ~X | X folding ...
* match.pd: ... here.
* gcc.dg/fold-ior-2.c: New test.
diff --git gcc/fold-const.c gcc/fold-const.c
index a447452..caba0cf 100644
--- gcc/fold-const.c
+++ gcc/fold-const.c
@@ -10928,24 +10928,6 @@ fold_binary_loc (location_t loc,
case BIT_IOR_EXPR:
bit_ior:
- /* ~X | X is -1. */
- if (TREE_CODE (arg0) == BIT_NOT_EXPR
- && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0))
- {
- t1 = build_zero_cst (type);
- t1 = fold_unary_loc (loc, BIT_NOT_EXPR, type, t1);
- return omit_one_operand_loc (loc, type, t1, arg1);
- }
-
- /* X | ~X is -1. */
- if (TREE_CODE (arg1) == BIT_NOT_EXPR
- && operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0))
- {
- t1 = build_zero_cst (type);
- t1 = fold_unary_loc (loc, BIT_NOT_EXPR, type, t1);
- return omit_one_operand_loc (loc, type, t1, arg0);
- }
-
/* Canonicalize (X & C1) | C2. */
if (TREE_CODE (arg0) == BIT_AND_EXPR
&& TREE_CODE (arg1) == INTEGER_CST
diff --git gcc/match.pd gcc/match.pd
index 0cf3d21..5dcbc1a 100644
--- gcc/match.pd
+++ gcc/match.pd
@@ -283,6 +283,12 @@ along with GCC; see the file COPYING3. If not see
(bit_and @0 integer_zerop@1)
@1)
+/* ~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); }))
+
/* x ^ x -> 0 */
(simplify
(bit_xor @0 @0)
diff --git gcc/testsuite/gcc.dg/fold-ior-2.c gcc/testsuite/gcc.dg/fold-ior-2.c
index e69de29..6abac9e 100644
--- gcc/testsuite/gcc.dg/fold-ior-2.c
+++ gcc/testsuite/gcc.dg/fold-ior-2.c
@@ -0,0 +1,47 @@
+/* { dg-do compile } */
+/* { dg-options "-O -fdump-tree-cddce1" } */
+
+int
+fn1 (int x)
+{
+ return ~x | x;
+}
+
+int
+fn2 (int x)
+{
+ return x | ~x;
+}
+
+unsigned int
+fn3 (unsigned int x)
+{
+ return ~x | x;
+}
+
+unsigned int
+fn4 (unsigned int x)
+{
+ return ~x | x;
+}
+
+int
+fn5 (int x)
+{
+ return ~x | (unsigned) x;
+}
+
+int
+fn6 (int x)
+{
+ return (unsigned) ~x | x;
+}
+
+int
+fn7 (int x)
+{
+ return ~(unsigned) x | x;
+}
+
+/* { dg-final { scan-tree-dump-not "~" "cddce1" } } */
+/* { dg-final { scan-tree-dump-not " \\| " "cddce1" } } */
Marek
