Re: [committed] c: C2x enums wider than int [PR36113]

[Jakub Jelinek <jakub@redhat.com>]

On Tue, Oct 18, 2022 at 02:08:40PM +0000, Joseph Myers wrote:
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/c2x-enum-1.c
> @@ -0,0 +1,104 @@
> +/* Test C2x enumerations with values not representable in int.  */
> +/* { dg-do compile } */
> +/* { dg-options "-std=c2x -pedantic-errors" } */
> +
> +/* Check a type while defining an enum (via a diagnostic for incompatible
> +   pointer types if the wrong type was chosen).  */
> +#define TYPE_CHECK(cst, type)						\
> +  cst ## _type_check = sizeof (1 ? (type *) 0 : (typeof (cst) *) 0)
> +
...

> +/* Likewise, for overflow from long to long long.  */
> +#if __LONG_LONG_MAX__ > __LONG_MAX__
> +enum e5 { e5a = __LONG_MAX__,
> +	  e5b, e5c, e5d = ((typeof (e5b)) -1) < 0,
> +	  e5e = (unsigned long) -1,
> +	  e5f, e5g = ((typeof (e5e)) -1) > 0,
> +	  TYPE_CHECK (e5a, long), TYPE_CHECK (e5e, unsigned long) };

This fails on x86_64-linux with -m32 and I assume most other 32-bit
targets, it works with
	  TYPE_CHECK (e5a, int), TYPE_CHECK (e5e, unsigned long) };
Haven't checked in detail, but if int and long have the same bitsize,
doesn't __LONG_MAX__ fit into int and so this new handling of large
enumerators doesn't apply?
Can we just change that unconditionally, or shall it be conditional
on #if __LONG_MAX__ > __INT_MAX__ (then use long, otherwise int)?

	Jakub