[Bug middle-end/111369] [14 Regression] ICE in handle_cast, gimple-lower-bitint.cc:1486 with -Os

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111369

--- Comment #2 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:64eeec25f11e31bed844ef0a95ef0f9661c3ab37

commit r14-4392-g64eeec25f11e31bed844ef0a95ef0f9661c3ab37
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Wed Oct 4 09:30:15 2023 +0200

    match.pd: Avoid other build_nonstandard_integer_type calls [PR111369]

    In the light of the PR111668 patch which shows that
    build_nonstandard_integer_type is needed (at least for some signed prec > 1
    BOOLEAN_TYPEs if we use e.g. negation), I've reworked this patch and
handled
    the last problematic build_nonstandard_integer_type call in there as well.

    In the x == cstN ? cst4 : cst3 optimization it uses
    build_nonstandard_integer_type solely for BOOLEAN_TYPEs (I really don't see
    why ENUMERAL_TYPEs would be a problem, we treat them in GIMPLE as uselessly
    convertible to same precision/sign INTEGER_TYPEs), for INTEGER_TYPEs it is
    really a no-op (might return a different type, but always INTEGER_TYPE
    with same TYPE_PRECISION same TYPE_UNSIGNED) and for BITINT_TYPE with
larger
    precisions really harmful (we shouldn't create large precision
    INTEGER_TYPEs).

    The a?~t:t optimization just omits the negation of a in type for 1-bit
    precision types or any BOOLEAN_TYPEs.  I think that is correct, because
    for both signed and unsigned 1-bit precision type, cast to type of a bool
    value yields already 0, -1 or 0, 1 values and for 1-bit precision negation
    of that is still 0, -1 or 0, 1 (except for invoking sometimes UB).
    And for signed larger precision BOOLEAN_TYPEs I think it is correct as
well,
    cast of [0, 1] to type yields 0, -1 and those can be xored with 0 or -1
    to yield the proper result, any other values would be UB.

    This fixes PR111369, where one of the bitint*.c tests FAILs with
    GCC_TEST_RUN_EXPENSIVE=1.

    2023-10-04  Jakub Jelinek  <jakub@redhat.com>

            PR middle-end/111369
            * match.pd (x == cstN ? cst4 : cst3): Use
            build_nonstandard_integer_type only if type1 is BOOLEAN_TYPE.
            Fix comment typo.  Formatting fix.
            (a?~t:t -> (-(a))^t): Always convert to type rather
            than using build_nonstandard_integer_type.  Perform negation
            only if type has precision > 1 and is not signed BOOLEAN_TYPE.