Hi all, One week ago I proposed a patch that catches ~(~x | y), (~x | y) & (x | ~y) and (~x | y) ^ (x | ~y) Although it was straightforward, it got only one review. Could you please review it? If you find it OK, I don't have push access. Is it possible for you to push it?
Best regards. History: patch: https://gcc.gnu.org/ml/gcc-patches/2018-08/msg01159.html review 1: https://gcc.gnu.org/ml/gcc-patches/2018-08/msg01169.html updated patch: https://gcc.gnu.org/ml/gcc-patches/2018-08/msg01299.html Below is an exact copy of the updated patch: 2018-08-21 MCC CS <deswurs...@users.noreply.github.com> gcc/ PR tree-optimization/87009 * match.pd: Add boolean optimizations. 2018-08-21 MCC CS <deswurs...@users.noreply.github.com> gcc/testsuite/ PR tree-optimization/87009 * gcc.dg/pr87009.c: New test. Index: gcc/match.pd =================================================================== --- gcc/match.pd (revision 263646) +++ gcc/match.pd (working copy) @@ -776,6 +776,11 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) (bit_not (bit_and:cs (bit_not @0) @1)) (bit_ior @0 (bit_not @1))) +/* ~(~a | b) --> a & ~b */ +(simplify + (bit_not (bit_ior:cs (bit_not @0) @1)) + (bit_and @0 (bit_not @1))) + /* Simplify (~X & Y) to X ^ Y if we know that (X & ~Y) is 0. */ #if GIMPLE (simplify @@ -981,6 +986,16 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) (bit_and:c (bit_ior:c @0 @1) (bit_xor:c @1 (bit_not @0))) (bit_and @0 @1)) +/* (~x | y) & (x | ~y) -> ~(x ^ y) */ +(simplify + (bit_and (bit_ior:c (bit_not @0) @1) (bit_ior:c @0 (bit_not @1))) + (bit_not (bit_xor @0 @1))) + +/* (~x | y) ^ (x | ~y) -> x ^ y */ +(simplify + (bit_xor (bit_ior:c (bit_not @0) @1) (bit_ior:c @0 (bit_not @1))) + (bit_xor @0 @1)) + /* ~x & ~y -> ~(x | y) ~x | ~y -> ~(x & y) */ (for op (bit_and bit_ior) Index: gcc/testsuite/gcc.dg/pr87009.c =================================================================== --- gcc/testsuite/gcc.dg/pr87009.c (nonexistent) +++ gcc/testsuite/gcc.dg/pr87009.c (working copy) @@ -0,0 +1,23 @@ +/* { dg-do compile } */ +/* { dg-options "-O -fdump-tree-original" } */ +/* { dg-final { scan-tree-dump-times "return s \\^ x;" 4 "original" } } */ + +int f1 (int x, int s) +{ + return ~(~(x|s)|x)|~(~(x|s)|s); +} + +int f2 (int x, int s) +{ + return ~(~(~x&s)&~(x&~s)); +} + +int f3 (int x, int s) +{ + return ~((x|~s)&(~x|s)); +} + +int f4 (int x, int s) +{ + return (x|~s)^(~x|s); +}
