On Fri, Aug 25, 2023 at 6:22 PM Andrew Pinski via Gcc-patches <gcc-patches@gcc.gnu.org> wrote: > > 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.
OK. > 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 >