On Tue, May 12, 2026 at 11:58 PM Andrew Pinski
<[email protected]> wrote:
>
> Canonicalize `(type) (a CMP b)` to `(a CMP b) ? (type) true : (type) false`
> for
> floating point types. fold-const already does this so it makes sense to do it
> on
> the gimple level too. This also improves vectorization because a conversion
> from a comparison to a float does not need to implemented and also if it is
> implemented then selection of 1.0/0.0 is easier than the conversion would be.
>
> Bootstrapped and tested on x86_64-linux-gnu with no regressions.
>
> PR tree-optimization/115571
>
> gcc/ChangeLog:
>
> * match.pd (`(float)(a CMP b)`): New pattern.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.dg/tree-ssa/float-conv-1.c: New test.
>
> Signed-off-by: Andrew Pinski <[email protected]>
> ---
> gcc/match.pd | 6 ++++++
> gcc/testsuite/gcc.dg/tree-ssa/float-conv-1.c | 16 ++++++++++++++++
> 2 files changed, 22 insertions(+)
> create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/float-conv-1.c
>
> diff --git a/gcc/match.pd b/gcc/match.pd
> index 8dcf8c318cf..6f1c53e5d7b 100644
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -2733,6 +2733,12 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
> )
> )
>
> +/* Canonicalize `(type) (a CMP b)` to `(a CMP b) ? (type) true : (type)
> false`
> + for floating point types. */
> +(simplify
> + (float (convert:s (tcc_comparison@0 @1 @2)))
So we'll never end up with (float (tcc_comparison ...))?
Patch is OK, I was just curious.
Richard.
> + (cond @0 { build_one_cst (type); } { build_zero_cst (type); } ))
> +
> /* For integral types with undefined overflow and C != 0 fold
> x * C EQ/NE y * C into x EQ/NE y. */
> (for cmp (eq ne)
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/float-conv-1.c
> b/gcc/testsuite/gcc.dg/tree-ssa/float-conv-1.c
> new file mode 100644
> index 00000000000..ffb07c4b94d
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/float-conv-1.c
> @@ -0,0 +1,16 @@
> +/* PR tree-optimization/115571 */
> +/* { dg-do compile } */
> +/* { dg-options "-O1 -fdump-tree-optimized-raw" } */
> +
> +float f(float a)
> +{
> + int t = a < 0.5;
> + return t;
> +}
> +
> +float f0(float a)
> +{
> + return (short)(a < 0.5);
> +}
> +
> +/* { dg-final { scan-tree-dump-times "gimple_cond |gimple_assign <cond_expr"
> 2 "optimized" } } */
> --
> 2.43.0
>
