[Bug c/102989] Implement C2x's n2763 (_BitInt)

["cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102989

--- Comment #105 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:f76ae4369cb6f38e17510704e5b6e53847d2a648

commit r14-3754-gf76ae4369cb6f38e17510704e5b6e53847d2a648
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Wed Sep 6 17:39:15 2023 +0200

    C _BitInt incremental fixes [PR102989]

    On Wed, Aug 09, 2023 at 09:17:57PM +0000, Joseph Myers wrote:
    > > - _Complex _BitInt(N) isn't supported; again mainly because none of the
psABIs
    > >   mention how those should be passed/returned; in a limited way they
are
    > >   supported internally because the internal functions into which
    > >   __builtin_{add,sub,mul}_overflow{,_p} is lowered return COMPLEX_TYPE
as a
    > >   hack to return 2 values without using references/pointers
    >
    > What happens when the usual arithmetic conversions are applied to
    > operands, one of which is a complex integer type and the other of which
is
    > a wider _BitInt type?  I don't see anything in the code to disallow this
    > case (which would produce an expression with a _Complex _BitInt type), or
    > any testcases for it.

    I've added a sorry for that case (+ return the narrower COMPLEX_TYPE).
    Also added testcase to verify we don't create VECTOR_TYPEs of BITINT_TYPE
    even if they have mode precision and suitable size (others were rejected
    already before).

    > Other testcases I think should be present (along with any corresponding
    > changes needed to the code itself):
    >
    > * Verifying that the new integer constant suffix is rejected for C++.

    Done.

    > * Verifying appropriate pedwarn-if-pedantic for the new constant suffix
    > for versions of C before C2x (and probably for use of _BitInt type
    > specifiers before C2x as well) - along with the expected -Wc11-c2x-compat
    > handling (in C2x mode) / -pedantic -Wno-c11-c2x-compat in older modes.

    Done.

    Here is an incremental patch which does that.

    2023-09-06  Jakub Jelinek  <jakub@redhat.com>

            PR c/102989
    gcc/c/
            * c-decl.cc (finish_declspecs): Emit pedwarn_c11 on _BitInt.
            * c-typeck.cc (c_common_type): Emit sorry for common type between
            _Complex integer and larger _BitInt and return the _Complex
integer.
    gcc/c-family/
            * c-attribs.cc (type_valid_for_vector_size): Reject vector types
            with BITINT_TYPE elements even if they have mode precision and
            suitable size.
    gcc/testsuite/
            * gcc.dg/bitint-19.c: New test.
            * gcc.dg/bitint-20.c: New test.
            * gcc.dg/bitint-21.c: New test.
            * gcc.dg/bitint-22.c: New test.
            * gcc.dg/bitint-23.c: New test.
            * gcc.dg/bitint-24.c: New test.
            * gcc.dg/bitint-25.c: New test.
            * gcc.dg/bitint-26.c: New test.
            * gcc.dg/bitint-27.c: New test.
            * g++.dg/ext/bitint1.C: New test.
            * g++.dg/ext/bitint2.C: New test.
            * g++.dg/ext/bitint3.C: New test.
            * g++.dg/ext/bitint4.C: New test.
    libcpp/
            * expr.cc (cpp_classify_number): Diagnose wb literal suffixes
            for -pedantic* before C2X or -Wc11-c2x-compat.