This moves the pattern `(X & ~Y) | (~X & Y)` to use bitwise_inverted_equal_p so we can simplify earlier the case where X and Y are defined by comparisons. We were able to optimize to (!X)^(!Y) in the end due to the pattern added in r14-3110-g7fb65f102851248bafa0815 and the older pattern r13-4620-g4d9db4bdd458 . But folding it earlier is better.
OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions. Note pr87009.c now gets `return x ^ s; in one case where the test had been expecting `return s ^ x;` both are valid and would be expectly the same; just we now chose a slightly different order of simplification which causes the order of the operands to be different. gcc/ChangeLog: * match.pd (`(X & ~Y) | (~X & Y)`): Use bitwise_inverted_equal_p instead of specifically checking for ~X. gcc/testsuite/ChangeLog: * gcc.dg/tree-ssa/cmpbit-3.c: New test. * gcc.dg/pr87009.c: Update test. --- gcc/match.pd | 13 +++++----- gcc/testsuite/gcc.dg/pr87009.c | 2 +- gcc/testsuite/gcc.dg/tree-ssa/cmpbit-3.c | 33 ++++++++++++++++++++++++ 3 files changed, 41 insertions(+), 7 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/cmpbit-3.c diff --git a/gcc/match.pd b/gcc/match.pd index 70884bd48eb..e41403664d0 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -1228,12 +1228,13 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) /* Simplify (X & ~Y) |^+ (~X & Y) -> X ^ Y. */ (for op (bit_ior bit_xor plus) (simplify - (op (bit_and:c @0 (bit_not @1)) (bit_and:c (bit_not @0) @1)) - (bit_xor @0 @1)) - (simplify - (op:c (bit_and @0 INTEGER_CST@2) (bit_and (bit_not @0) INTEGER_CST@1)) - (if (~wi::to_wide (@2) == wi::to_wide (@1)) - (bit_xor @0 @1)))) + (op (bit_and:c @0 @2) (bit_and:c @3 @1)) + (with { bool wascmp0, wascmp1; } + (if (bitwise_inverted_equal_p (@2, @1, wascmp0) + && bitwise_inverted_equal_p (@0, @3, wascmp1) + && ((!wascmp0 && !wascmp1) + || element_precision (type) == 1)) + (bit_xor @0 @1))))) /* PR53979: Transform ((a ^ b) | a) -> (a | b) */ (simplify diff --git a/gcc/testsuite/gcc.dg/pr87009.c b/gcc/testsuite/gcc.dg/pr87009.c index eb8a4ecd920..6f0341d17cc 100644 --- a/gcc/testsuite/gcc.dg/pr87009.c +++ b/gcc/testsuite/gcc.dg/pr87009.c @@ -1,6 +1,6 @@ /* { dg-do compile } */ /* { dg-options "-O -fdump-tree-original" } */ -/* { dg-final { scan-tree-dump-times "return s \\^ x;" 4 "original" } } */ +/* { dg-final { scan-tree-dump-times "return s \\^ x;|return x \\^ s;" 4 "original" } } */ int f1 (int x, int s) { diff --git a/gcc/testsuite/gcc.dg/tree-ssa/cmpbit-3.c b/gcc/testsuite/gcc.dg/tree-ssa/cmpbit-3.c new file mode 100644 index 00000000000..936c0934a10 --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/cmpbit-3.c @@ -0,0 +1,33 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fdump-tree-optimized-raw -fdump-tree-dse1-raw -fdump-tree-forwprop1" } */ + +_Bool f(int a, int b) +{ + _Bool X = a==1, Y = b == 2; +return (X & !Y) | (!X & Y); +} + + +_Bool f1(int a, int b) +{ + _Bool X = a==1, Y = b == 2; + _Bool c = (X & !Y); + _Bool d = (!X & Y); + return c | d; +} + +/* Both of these should be optimized to (a==1) ^ (b==2) or (a != 1) ^ (b != 2) */ +/* { dg-final { scan-tree-dump-not "gimple_cond " "optimized" } } */ +/* { dg-final { scan-tree-dump-not "gimple_phi " "optimized" } } */ +/* { dg-final { scan-tree-dump-times "ne_expr|eq_expr, " 4 "optimized" } } */ +/* { dg-final { scan-tree-dump-times "bit_xor_expr, " 2 "optimized" } } */ +/* { dg-final { scan-tree-dump-times "gimple_assign " 6 "optimized" } } */ + +/* Both of these should be optimized early in the pipeline after forwprop1 */ +/* { dg-final { scan-tree-dump-times "ne_expr|eq_expr, " 4 "forwprop1" { xfail *-*-* } } } */ +/* { dg-final { scan-tree-dump-times "bit_xor_expr, " 2 "forwprop1" { xfail *-*-* } } } */ +/* { dg-final { scan-tree-dump-times "gimple_assign " 6 "forwprop1" { xfail *-*-* } } } */ +/* Note forwprop1 does not remove all unused statements sometimes so test dse1 also. */ +/* { dg-final { scan-tree-dump-times "ne_expr|eq_expr, " 4 "dse1" } } */ +/* { dg-final { scan-tree-dump-times "bit_xor_expr, " 2 "dse1" } } */ +/* { dg-final { scan-tree-dump-times "gimple_assign " 6 "dse1" } } */ -- 2.31.1