On Wed, May 8, 2024 at 5:25 AM Andrew Pinski <quic_apin...@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_apin...@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
>
