Even though this gets optimized by reassociation, catching it more often will always be better.
Note the reason why I didn't add `(X ^ ~Y) ^ Y` is that it gets caught by prefering `~(X ^ Y)` to `(X ^ ~Y)` which then it is caught by the the pattern for `(X ^ Y) ^ Y` already. PR tree-optimization/111543 gcc/ChangeLog: * match.pd (`(X & ~Y) & Y`, `(X | ~Y) | Y`): New patterns. gcc/testsuite/ChangeLog: * gcc.dg/tree-ssa/bitops-4.c: New test. --- gcc/match.pd | 17 +++++++++++++++++ gcc/testsuite/gcc.dg/tree-ssa/bitops-4.c | 18 ++++++++++++++++++ 2 files changed, 35 insertions(+) create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/bitops-4.c diff --git a/gcc/match.pd b/gcc/match.pd index 0aa815f4118..a17778fbaa6 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -1806,6 +1806,23 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) (simplify (bit_xor:c (convert1? (bit_xor:c @0 @@1)) (convert2? @1)) (convert @0)) + +/* (X & ~Y) & Y -> 0 */ +(simplify + (bit_and:c (bit_and @0 @1) @2) + (with { bool wascmp; } + (if (bitwise_inverted_equal_p (@0, @2, wascmp) + || bitwise_inverted_equal_p (@1, @2, wascmp)) + { wascmp ? constant_boolean_node (false, type) : build_zero_cst (type); }))) +/* (X | ~Y) | Y -> -1 */ +(simplify + (bit_ior:c (bit_ior @0 @1) @2) + (with { bool wascmp; } + (if ((bitwise_inverted_equal_p (@0, @2, wascmp) + || bitwise_inverted_equal_p (@1, @2, wascmp)) + && (!wascmp || element_precision (type) == 1)) + { build_all_ones_cst (TREE_TYPE (@0)); }))) + /* (X & Y) & (X & Z) -> (X & Y) & Z (X | Y) | (X | Z) -> (X | Y) | Z */ (for op (bit_and bit_ior) diff --git a/gcc/testsuite/gcc.dg/tree-ssa/bitops-4.c b/gcc/testsuite/gcc.dg/tree-ssa/bitops-4.c new file mode 100644 index 00000000000..73c8f39d28f --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/bitops-4.c @@ -0,0 +1,18 @@ +/* { dg-do compile } */ +/* { dg-options "-O1 -fdump-tree-optimized -fdump-tree-ccp1" } */ +/* PR tree-optimization/111543 */ + +void f_or(int a, int b, int *por) +{ + int c = ~a; + *por = (c | b) | a; +} +void f_and(int a, int b, int *pand) +{ + int c = ~a; + *pand = (c & b) & a; +} +/* { dg-final { scan-tree-dump-times "pand_\[0-9\]+.D. = 0" 1 "optimized" } } */ +/* { dg-final { scan-tree-dump-times "por_\[0-9\]+.D. = -1" 1 "optimized" } } */ +/* { dg-final { scan-tree-dump-times "pand_\[0-9\]+.D. = 0" 1 "ccp1" } } */ +/* { dg-final { scan-tree-dump-times "por_\[0-9\]+.D. = -1" 1 "ccp1" } } */ -- 2.31.1