Message ID | 20240508032444.573884-1-quic_apinski@quicinc.com |
---|---|
State | New |
Headers | show |
Series | match: `a CMP nonnegative ? a : ABS<a>` simplified to just `ABS<a>` [PR112392] | expand |
On Wed, May 8, 2024 at 5:25 AM Andrew Pinski <quic_apinski@quicinc.com> wrote: > > We can optimize `a == nonnegative ? a : ABS<a>`, `a > nonnegative ? a : ABS<a>` > and `a >= nonnegative ? a : ABS<a>` into `ABS<a>`. This allows removal of > some extra comparison and extra conditional moves in some cases. > I don't remember where I had found though but it is simple to add so > let's add it. > > Bootstrapped and tested on x86_64-linux-gnu with no regressions. > > Note I have a secondary pattern for the equal case as either a or nonnegative > could be used. OK > PR tree-optimization/112392 > > gcc/ChangeLog: > > * match.pd (`x CMP nonnegative ? x : ABS<x>`): New pattern; > where CMP is ==, > and >=. > (`x CMP nonnegative@y ? y : ABS<x>`): New pattern. > > gcc/testsuite/ChangeLog: > > * gcc.dg/tree-ssa/phi-opt-41.c: New test. > > Signed-off-by: Andrew Pinski <quic_apinski@quicinc.com> > --- > gcc/match.pd | 15 ++++++++++ > gcc/testsuite/gcc.dg/tree-ssa/phi-opt-41.c | 34 ++++++++++++++++++++++ > 2 files changed, 49 insertions(+) > create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/phi-opt-41.c > > diff --git a/gcc/match.pd b/gcc/match.pd > index 03a03c31233..07e743ae464 100644 > --- a/gcc/match.pd > +++ b/gcc/match.pd > @@ -5876,6 +5876,21 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) > (convert (absu:utype @0))) > @3)))) > > +/* X > Positive ? X : ABS(X) -> ABS(X) */ > +/* X >= Positive ? X : ABS(X) -> ABS(X) */ > +/* X == Positive ? X : ABS(X) -> ABS(X) */ > +(for cmp (eq gt ge) > + (simplify > + (cond (cmp:c @0 tree_expr_nonnegative_p@1) @0 (abs@3 @0)) > + (if (INTEGRAL_TYPE_P (type)) > + @3))) > + > +/* X == Positive ? Positive : ABS(X) -> ABS(X) */ > +(simplify > + (cond (eq:c @0 tree_expr_nonnegative_p@1) @1 (abs@3 @0)) > + (if (INTEGRAL_TYPE_P (type)) > + @3)) > + > /* (X + 1) > Y ? -X : 1 simplifies to X >= Y ? -X : 1 when > X is unsigned, as when X + 1 overflows, X is -1, so -X == 1. */ > (simplify > diff --git a/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-41.c b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-41.c > new file mode 100644 > index 00000000000..9774e283a7b > --- /dev/null > +++ b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-41.c > @@ -0,0 +1,34 @@ > +/* { dg-do compile } */ > +/* { dg-options "-O1 -fdump-tree-phiopt1" } */ > +/* PR tree-optimization/112392 */ > + > +int feq_1(int a, unsigned char b) > +{ > + int absb = b; > + if (a == absb) return absb; > + return a > 0 ? a : -a; > +} > +int feq_2(int a, unsigned char b) > +{ > + int absb = b; > + if (a == absb) return a; > + return a > 0 ? a : -a; > +} > + > +int fgt(int a, unsigned char b) > +{ > + int absb = b; > + if (a > absb) return a; > + return a > 0 ? a : -a; > +} > + > +int fge(int a, unsigned char b) > +{ > + int absb = b; > + if (a >= absb) return a; > + return a > 0 ? a : -a; > +} > + > + > +/* { dg-final { scan-tree-dump-not "if " "phiopt1" } } */ > +/* { dg-final { scan-tree-dump-times "ABS_EXPR <" 4 "phiopt1" } } */ > -- > 2.43.0 >
diff --git a/gcc/match.pd b/gcc/match.pd index 03a03c31233..07e743ae464 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -5876,6 +5876,21 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) (convert (absu:utype @0))) @3)))) +/* X > Positive ? X : ABS(X) -> ABS(X) */ +/* X >= Positive ? X : ABS(X) -> ABS(X) */ +/* X == Positive ? X : ABS(X) -> ABS(X) */ +(for cmp (eq gt ge) + (simplify + (cond (cmp:c @0 tree_expr_nonnegative_p@1) @0 (abs@3 @0)) + (if (INTEGRAL_TYPE_P (type)) + @3))) + +/* X == Positive ? Positive : ABS(X) -> ABS(X) */ +(simplify + (cond (eq:c @0 tree_expr_nonnegative_p@1) @1 (abs@3 @0)) + (if (INTEGRAL_TYPE_P (type)) + @3)) + /* (X + 1) > Y ? -X : 1 simplifies to X >= Y ? -X : 1 when X is unsigned, as when X + 1 overflows, X is -1, so -X == 1. */ (simplify diff --git a/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-41.c b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-41.c new file mode 100644 index 00000000000..9774e283a7b --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-41.c @@ -0,0 +1,34 @@ +/* { dg-do compile } */ +/* { dg-options "-O1 -fdump-tree-phiopt1" } */ +/* PR tree-optimization/112392 */ + +int feq_1(int a, unsigned char b) +{ + int absb = b; + if (a == absb) return absb; + return a > 0 ? a : -a; +} +int feq_2(int a, unsigned char b) +{ + int absb = b; + if (a == absb) return a; + return a > 0 ? a : -a; +} + +int fgt(int a, unsigned char b) +{ + int absb = b; + if (a > absb) return a; + return a > 0 ? a : -a; +} + +int fge(int a, unsigned char b) +{ + int absb = b; + if (a >= absb) return a; + return a > 0 ? a : -a; +} + + +/* { dg-final { scan-tree-dump-not "if " "phiopt1" } } */ +/* { dg-final { scan-tree-dump-times "ABS_EXPR <" 4 "phiopt1" } } */
We can optimize `a == nonnegative ? a : ABS<a>`, `a > nonnegative ? a : ABS<a>` and `a >= nonnegative ? a : ABS<a>` into `ABS<a>`. This allows removal of some extra comparison and extra conditional moves in some cases. I don't remember where I had found though but it is simple to add so let's add it. Bootstrapped and tested on x86_64-linux-gnu with no regressions. Note I have a secondary pattern for the equal case as either a or nonnegative could be used. PR tree-optimization/112392 gcc/ChangeLog: * match.pd (`x CMP nonnegative ? x : ABS<x>`): New pattern; where CMP is ==, > and >=. (`x CMP nonnegative@y ? y : ABS<x>`): New pattern. gcc/testsuite/ChangeLog: * gcc.dg/tree-ssa/phi-opt-41.c: New test. Signed-off-by: Andrew Pinski <quic_apinski@quicinc.com> --- gcc/match.pd | 15 ++++++++++ gcc/testsuite/gcc.dg/tree-ssa/phi-opt-41.c | 34 ++++++++++++++++++++++ 2 files changed, 49 insertions(+) create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/phi-opt-41.c