[Bug c/127486] New: Implicitly zero-initialized hardbool object uses zero bits instead of its false representation

[bic60176 at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=127486

            Bug ID: 127486
           Summary: Implicitly zero-initialized hardbool object uses zero
                    bits instead of its false representation
           Product: gcc
           Version: 17.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: bic60176 at gmail dot com
  Target Milestone: ---

typedef char __attribute__((__hardbool__(0x5a))) hbool;

static hbool zeroinit;

int main(void)
{
    unsigned char rep;
    __builtin_memcpy(&rep, &zeroinit, 1);

    if (rep != 0x5a)
        return 2;
    if (zeroinit)
        return 3;
    return 0;
}

gcc -O0 test.c -o test && ./test
echo $?

Actual: returns 2; storage contains zero.
Expected: returns 0; implicit initialization should produce the declared false
representation 0x5a.