On Tue, 19 Sep 2023, Jakub Jelinek wrote:
> Hi!
>
> On Tue, Sep 12, 2023 at 05:27:30PM +0000, Joseph Myers wrote:
> > On Tue, 12 Sep 2023, Jakub Jelinek via Gcc-patches wrote:
> >
> > > And by ensuring we never create 1-bit signed BITINT_TYPE e.g. the backends
> > > don't need to worry about them.
> > >
> > > But I admit I don't feel strongly about that.
> > >
> > > Joseph, what do you think about this?
> >
> > I think it's appropriate to avoid 1-bit signed BITINT_TYPE consistently.
>
> Here is a patch which does that. In addition to the previously changed two
> hunks it also adds a checking assertion that we don't create
> signed _BitInt(0), unsigned _BitInt(0) or signed _BitInt(1) types.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
OK.
Thanks,
Richard.
> 2023-09-18 Jakub Jelinek <ja...@redhat.com>
>
> gcc/
> * tree.cc (build_bitint_type): Assert precision is not 0, or
> for signed types 1.
> (signed_or_unsigned_type_for): Return INTEGER_TYPE for signed variant
> of unsigned _BitInt(1).
> gcc/c-family/
> * c-common.cc (c_common_signed_or_unsigned_type): Return INTEGER_TYPE
> for signed variant of unsigned _BitInt(1).
>
> --- gcc/tree.cc.jj 2023-09-11 17:01:17.612714178 +0200
> +++ gcc/tree.cc 2023-09-18 12:36:37.598912717 +0200
> @@ -7179,6 +7179,8 @@ build_bitint_type (unsigned HOST_WIDE_IN
> {
> tree itype, ret;
>
> + gcc_checking_assert (precision >= 1 + !unsignedp);
> +
> if (unsignedp)
> unsignedp = MAX_INT_CACHED_PREC + 1;
>
> @@ -11096,7 +11098,7 @@ signed_or_unsigned_type_for (int unsigne
> else
> return NULL_TREE;
>
> - if (TREE_CODE (type) == BITINT_TYPE)
> + if (TREE_CODE (type) == BITINT_TYPE && (unsignedp || bits > 1))
> return build_bitint_type (bits, unsignedp);
> return build_nonstandard_integer_type (bits, unsignedp);
> }
> --- gcc/c-family/c-common.cc.jj 2023-09-11 17:01:17.517715431 +0200
> +++ gcc/c-family/c-common.cc 2023-09-18 12:35:06.829126858 +0200
> @@ -2739,7 +2739,9 @@ c_common_signed_or_unsigned_type (int un
> || TYPE_UNSIGNED (type) == unsignedp)
> return type;
>
> - if (TREE_CODE (type) == BITINT_TYPE)
> + if (TREE_CODE (type) == BITINT_TYPE
> + /* signed _BitInt(1) is invalid, avoid creating that. */
> + && (unsignedp || TYPE_PRECISION (type) > 1))
> return build_bitint_type (TYPE_PRECISION (type), unsignedp);
>
> #define TYPE_OK(node)
> \
>
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)
