On Tue, Sep 24, 2024 at 10:58 AM Eikansh Gupta
<quic_eikag...@quicinc.com> wrote:
>
> This patch simplify `(trunc)copysign ((extend)x, CST)` to `copysign (x,
> -1.0/1.0)`
> depending on the sign of CST. Previously, it was simplified to `copysign (x,
> CST)`.
> It can be optimized as the sign of the CST matters, not the value.
>
> The patch also simplify `(trunc)abs (extend x)` to `abs (x)`.
Please always split unrelated transforms. The abs transform is OK.
We already have
/* Simplify (trunc)copysign ((extend)x, (extend)y) to copysignf (x, y),
x,y is float value, similar for _Float16/double. */
(for copysigns (COPYSIGN_ALL)
(simplify
(convert (copysigns (convert@2 @0) (convert @1)))
(if (optimize
&& !HONOR_SNANS (@2)
&& types_match (type, TREE_TYPE (@0))
&& types_match (type, TREE_TYPE (@1))
&& TYPE_PRECISION (type) < TYPE_PRECISION (TREE_TYPE (@2))
&& direct_internal_fn_supported_p (IFN_COPYSIGN,
type, OPTIMIZE_FOR_BOTH))
(IFN_COPYSIGN @0 @1))))
you could have extended that to cover the REAL_CST case via
matching
(convert (copysigns (convert@2 @0) (convert2? @1)))
I think. Can you try?
> PR tree-optimization/112472
>
> gcc/ChangeLog:
>
> * match.pd ((trunc)copysign ((extend)x, -CST) --> copysign (x,
> -1.0)): New pattern.
> ((trunc)abs (extend x) --> abs (x)): New pattern.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.dg/tree-ssa/pr112472.c: New test.
> ---
> gcc/match.pd | 24 +++++++++++++++++++++++-
> gcc/testsuite/gcc.dg/tree-ssa/pr112472.c | 22 ++++++++++++++++++++++
> 2 files changed, 45 insertions(+), 1 deletion(-)
> create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr112472.c
>
> diff --git a/gcc/match.pd b/gcc/match.pd
> index 940292d0d49..52dc8b539fc 100644
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -8535,7 +8535,29 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
> && TYPE_PRECISION (type) < TYPE_PRECISION (TREE_TYPE (@2))
> && direct_internal_fn_supported_p (IFN_COPYSIGN,
> type, OPTIMIZE_FOR_BOTH))
> - (IFN_COPYSIGN @0 @1))))
> + (IFN_COPYSIGN @0 @1)))
> + /* (trunc)copysign (extend)x, CST) to copysign (x, -1.0/1.0) */
> + (simplify
> + (convert (copysigns (convert@2 @0) REAL_CST@1))
> + (if (optimize
> + && !HONOR_SNANS (@2)
> + && types_match (type, TREE_TYPE (@0))
> + && TYPE_PRECISION (type) < TYPE_PRECISION (TREE_TYPE (@2))
> + && direct_internal_fn_supported_p (IFN_COPYSIGN,
> + type, OPTIMIZE_FOR_BOTH))
> + (if (REAL_VALUE_NEGATIVE (TREE_REAL_CST (@1)))
> + (IFN_COPYSIGN @0 { build_minus_one_cst (type); })
> + (IFN_COPYSIGN @0 { build_one_cst (type); })))))
> +
> +/* (trunc)abs (extend x) --> abs (x)
> + x is a float value */
> +(simplify
> + (convert (abs (convert@1 @0)))
> + (if (optimize
> + && !HONOR_SNANS (@1)
> + && types_match (type, TREE_TYPE (@0))
> + && TYPE_PRECISION (type) < TYPE_PRECISION (TREE_TYPE (@1)))
> + (abs @0)))
>
> (for froms (BUILT_IN_FMAF BUILT_IN_FMA BUILT_IN_FMAL)
> tos (IFN_FMA IFN_FMA IFN_FMA)
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr112472.c
> b/gcc/testsuite/gcc.dg/tree-ssa/pr112472.c
> new file mode 100644
> index 00000000000..8f97278ffe8
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr112472.c
> @@ -0,0 +1,22 @@
> +/* PR tree-optimization/109878 */
> +/* { dg-do compile } */
> +/* { dg-options "-O1 -fdump-tree-optimized" } */
> +
> +/* Optimized to .COPYSIGN(a, -1.0e+0) */
> +float f(float a)
> +{
> + return (float)__builtin_copysign(a, -3.0);
> +}
> +
> +/* This gets converted to (float) abs((double) a)
> + With the patch it is optimized to abs(a) */
> +float f2(float a)
> +{
> + return (float)__builtin_copysign(a, 5.0);
> +}
> +
> +/* { dg-final { scan-tree-dump-not "= __builtin_copysign" "optimized" } } */
> +/* { dg-final { scan-tree-dump-not " double " "optimized" { target
> ifn_copysign } } } */
> +/* { dg-final { scan-tree-dump-times ".COPYSIGN" 1 "optimized" { target
> ifn_copysign } } } */
> +/* { dg-final { scan-tree-dump-times "-1.0e\\+0" 1 "optimized" { target
> ifn_copysign } } } */
> +/* { dg-final { scan-tree-dump-times " ABS_EXPR " 1 "optimized" { target
> ifn_copysign } } } */
> --
> 2.17.1
>
