[Bug libgcc/113604] runtime SIGFPE with _BitInt() division

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113604

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |jakub at gcc dot gnu.org

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
longlong.h documents that
   HIGH_NUMERATOR must be less
   than DENOMINATOR for correct operation.  If, in addition, the most
   significant bit of DENOMINATOR must be 1, then the pre-processor symbol
   UDIV_NEEDS_NORMALIZATION is defined to 1.
While UDIV_NEEDS_NORMALIZATION is 1 only on sh32 and arches which don't define
their udiv_qrnnd and fallback to C, the first requirement is there for all
arches.
0xffffffff'ffffffff'ffff8000'03e00001uwb / 0xffffffff'ffffffffuwb
is 0x1'00000000'00000000uwb and
0xffffffff'ffffffff'ffff8000'03e00001uwb % 0xffffffff'ffffffffuwb
is 0xffff8000'03e00001uwb, so the quotient isn't representable in 64-bit
number, which is why SIGFPE is triggered.