This patch brings three new patterns for match.pd. I think these are rare, but it shouldn't hurt to have them. (I suppose you'd be happier if I was moving patterns from fold-const to match.pd. I'll work on that as well.)
Given previous discussion, I don't think there's much to say otherwise, but I'd appreciate if someone could glance over this. Bootstrapped/regtested on x86_64-linux, ok for trunk? 2015-06-12 Marek Polacek <pola...@redhat.com> * match.pd ((x & y) + (x ^ y) -> x | y, (x & y) + (x | y) -> x + y, (x | y) - (x ^ y) -> x & y): New patterns. * gcc.dg/fold-plus-1.c: New test. * gcc.dg/fold-plus-2.c: New test. * gcc.dg/fold-minus-2.c: New test. --- gcc/match.pd +++ gcc/match.pd @@ -325,6 +325,21 @@ along with GCC; see the file COPYING3. If not see (bit_xor:c (bit_and @0 @1) (bit_ior @0 @1)) (bit_xor @0 @1)) +/* (x & y) + (x ^ y) -> x | y */ +(simplify + (plus:c (bit_and @0 @1) (bit_xor @0 @1)) + (bit_ior @0 @1)) + +/* (x & y) + (x | y) -> x + y */ +(simplify + (plus:c (bit_and @0 @1) (bit_ior @0 @1)) + (plus @0 @1)) + +/* (x | y) - (x ^ y) -> x & y */ +(simplify + (minus (bit_ior @0 @1) (bit_xor @0 @1)) + (bit_and @0 @1)) + (simplify (abs (negate @0)) (abs @0)) --- gcc/testsuite/gcc.dg/fold-plus-1.c +++ gcc/testsuite/gcc.dg/fold-plus-1.c @@ -0,0 +1,70 @@ +/* { dg-do compile } */ +/* { dg-options "-O -fdump-tree-cddce1" } */ + +int +fn1 (int a, int b) +{ + int tem1 = a & b; + int tem2 = a ^ b; + return tem1 + tem2; +} + +int +fn2 (int a, int b) +{ + int tem1 = b & a; + int tem2 = a ^ b; + return tem1 + tem2; +} + +int +fn3 (int a, int b) +{ + int tem1 = a & b; + int tem2 = b ^ a; + return tem1 + tem2; +} + +int +fn4 (int a, int b) +{ + int tem1 = b & a; + int tem2 = b ^ a; + return tem1 + tem2; +} + +int +fn5 (int a, int b) +{ + int tem1 = a ^ b; + int tem2 = a & b; + return tem1 + tem2; +} + +int +fn6 (int a, int b) +{ + int tem1 = b ^ a; + int tem2 = a & b; + return tem1 + tem2; +} + +int +fn7 (int a, int b) +{ + int tem1 = a ^ b; + int tem2 = b & a; + return tem1 + tem2; +} + +int +fn8 (int a, int b) +{ + int tem1 = b ^ a; + int tem2 = b & a; + return tem1 + tem2; +} + +/* { dg-final { scan-tree-dump-not " & " "cddce1" } } */ +/* { dg-final { scan-tree-dump-not " \\^ " "cddce1" } } */ +/* { dg-final { scan-tree-dump-not " \\+ " "cddce1" } } */ --- gcc/testsuite/gcc.dg/fold-plus-2.c +++ gcc/testsuite/gcc.dg/fold-plus-2.c @@ -0,0 +1,69 @@ +/* { dg-do compile } */ +/* { dg-options "-O -fdump-tree-cddce1" } */ + +int +fn1 (int a, int b) +{ + int tem1 = a & b; + int tem2 = a | b; + return tem1 + tem2; +} + +int +fn2 (int a, int b) +{ + int tem1 = b & a; + int tem2 = a | b; + return tem1 + tem2; +} + +int +fn3 (int a, int b) +{ + int tem1 = a & b; + int tem2 = b | a; + return tem1 + tem2; +} + +int +fn4 (int a, int b) +{ + int tem1 = b & a; + int tem2 = b | a; + return tem1 + tem2; +} + +int +fn5 (int a, int b) +{ + int tem1 = a | b; + int tem2 = a & b; + return tem1 + tem2; +} + +int +fn6 (int a, int b) +{ + int tem1 = b | a; + int tem2 = a & b; + return tem1 + tem2; +} + +int +fn7 (int a, int b) +{ + int tem1 = a | b; + int tem2 = b & a; + return tem1 + tem2; +} + +int +fn8 (int a, int b) +{ + int tem1 = b | a; + int tem2 = b & a; + return tem1 + tem2; +} + +/* { dg-final { scan-tree-dump-not " & " "cddce1" } } */ +/* { dg-final { scan-tree-dump-not " \\| " "cddce1" } } */ --- gcc/testsuite/gcc.dg/fold-minus-2.c +++ gcc/testsuite/gcc.dg/fold-minus-2.c @@ -0,0 +1,37 @@ +/* { dg-do compile } */ +/* { dg-options "-O -fdump-tree-cddce1" } */ + +int +fn1 (int a, int b) +{ + int tem1 = a | b; + int tem2 = a ^ b; + return tem1 - tem2; +} + +int +fn2 (int a, int b) +{ + int tem1 = b | a; + int tem2 = a ^ b; + return tem1 - tem2; +} + +int +fn3 (int a, int b) +{ + int tem1 = a | b; + int tem2 = b ^ a; + return tem1 - tem2; +} + +int +fn4 (int a, int b) +{ + int tem1 = b | a; + int tem2 = b ^ a; + return tem1 - tem2; +} + +/* { dg-final { scan-tree-dump-not " \\^ " "cddce1" } } */ +/* { dg-final { scan-tree-dump-not " \\| " "cddce1" } } */ Marek