Re: [PATCH] Fix ICE on _Fract division (PR tree-optimization/81428)

[Richard Biener <richard.guenther@gmail.com>]

On Thu, Jul 13, 2017 at 10:41 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> Hi!
>
> _Fract types can't express 1, other spots that call build_one_cst already
> make sure that the type is integral or uses the !ALL_FRACT_MODE_P (TYPE_MODE (type))
> check I've added in this patch.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux and tested with a
> cross to arm on the testcase.  Ok for trunk?

Ok.

> 2017-07-13  Jakub Jelinek  <jakub@redhat.com>
>
>         PR tree-optimization/81428
>         * match.pd (X / X -> one): Don't optimize _Fract divisions, as 1
>         can't be built for those types.
>
>         * gcc.dg/fixed-point/pr81428.c: New test.
>
> --- gcc/match.pd.jj     2017-07-13 15:37:34.000000000 +0200
> +++ gcc/match.pd        2017-07-13 15:46:11.194593051 +0200
> @@ -243,8 +243,9 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
>   /* X / X is one.  */
>   (simplify
>    (div @0 @0)
> -  /* But not for 0 / 0 so that we can get the proper warnings and errors.  */
> -  (if (!integer_zerop (@0))
> +  /* But not for 0 / 0 so that we can get the proper warnings and errors.
> +     And not for _Fract types where we can't build 1.  */
> +  (if (!integer_zerop (@0) && !ALL_FRACT_MODE_P (TYPE_MODE (type)))
>     { build_one_cst (type); }))
>   /* X / abs (X) is X < 0 ? -1 : 1.  */
>   (simplify
> --- gcc/testsuite/gcc.dg/fixed-point/pr81428.c.jj       2017-07-13 15:49:52.980806440 +0200
> +++ gcc/testsuite/gcc.dg/fixed-point/pr81428.c  2017-07-13 15:49:29.000000000 +0200
> @@ -0,0 +1,9 @@
> +/* PR tree-optimization/81428 */
> +/* { dg-do compile } */
> +/* { dg-options "-O2" } */
> +
> +void
> +foo (long _Fract *a, long _Fract *b)
> +{
> +  *b = *a / *a;
> +}
>
>         Jakub