Re: [PATCH] range-op-float: Remove inappropriate frange_drop_infs call [PR126549]

On 2026-08-04 09:15, Jakub Jelinek wrote:

OK

> Hi!
> 
> For integer to floating conversions I've added frange_drop_infs
> call into the handler.  Supposedly I thought that integers converted
> to floating point are never +-inf, but that is clearly not the case
> as the testcases show.  For _Float16 it can be +-inf very easily,
> as the finite range is just [-65504.0f16,65504.0f16], for others
> all one needs is a large enough _BitInt.
> 
> The following patch just drops that call.  In the common cases,
> +-inf will not appear in the range anyway, lb and ub will be usually
> finite.
> 
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
> 
> 2026-08-04  Jakub Jelinek  <[email protected]>
> 
> 	PR tree-optimization/126549
> 	* range-op-float.cc (operator_cast::fold_range): Don't call
> 	frange_drop_infs.
> 
> 	* gcc.dg/torture/pr126549.c: New test.
> 	* gcc.dg/torture/bitint-107.c: New test.
> 
> --- gcc/range-op-float.cc.jj	2026-07-31 08:55:56.406542081 +0200
> +++ gcc/range-op-float.cc	2026-08-03 13:45:49.794387749 +0200
> @@ -3148,7 +3148,6 @@ operator_cast::fold_range (frange &r, tr
>  	frange_nextafter (mode, ub, dconstinf);
>      }
>    r.set (type, lb, ub, nan_state (false));
> -  frange_drop_infs (r, type);
>    if (r.undefined_p ())
>      r.set_varying (type);
>    return true;
> --- gcc/testsuite/gcc.dg/torture/pr126549.c.jj	2026-08-03
> 13:58:12.124012322 +0200
> +++ gcc/testsuite/gcc.dg/torture/pr126549.c	2026-08-03 
> 13:57:58.915179144 +0200
> @@ -0,0 +1,18 @@
> +/* PR tree-optimization/126549 */
> +/* { dg-do run { target float16 } } */
> +/* { dg-add-options float16 } */
> +
> +[[gnu::noipa]] int
> +foo (unsigned a)
> +{
> +  unsigned u = a % 100001U;
> +  _Float16 h = (_Float16) u;
> +  return h > 65504.0f16;
> +}
> +
> +int
> +main ()
> +{
> +  if (foo (70000U) != 1)
> +    __builtin_abort ();
> +}
> --- gcc/testsuite/gcc.dg/torture/bitint-107.c.jj	2026-08-03
> 13:58:50.906522507 +0200
> +++ gcc/testsuite/gcc.dg/torture/bitint-107.c	2026-08-03
> 13:59:20.568147890 +0200
> @@ -0,0 +1,18 @@
> +/* PR tree-optimization/126549 */
> +/* { dg-do run { target { float32 && bitint575 } } } */
> +/* { dg-add-options float32 } */
> +
> +[[gnu::noipa]] int
> +foo (unsigned _BitInt(133) a)
> +{
> +  unsigned _BitInt(133) u = a % 
> 5444517870735015415413993718908291383300uwb;
> +  _Float32 h = (_Float32) u;
> +  return h > __FLT32_MAX__;
> +}
> +
> +int
> +main ()
> +{
> +  if (foo (5444517870735015415413993718908291383295uwb) != 1)
> +    __builtin_abort ();
> +}
> 
> 	Jakub