[Bug target/88234] UBsan and runtime error: signed integer overflow using unsigned vector

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88234

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |segher at gcc dot gnu.org,
                   |                            |willschm at gcc dot gnu.org

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
I guess it depends on how vec_add is supposed to be defined.
It is certainly expanded as signed int vector addition, already gimple dump
(and original too) has something like:
        _1 = VIEW_CONVERT_EXPR<__vector signed int>(a);
        _2 = VIEW_CONVERT_EXPR<__vector signed int>(b);
        _3 = _1 + _2;
        c = VIEW_CONVERT_EXPR<__vector unsigned int>(_3);
        _4 = VIEW_CONVERT_EXPR<__vector signed char>(c);
So, either the testcase is wrong (if vec_add is defined to operate on signed
vectors) or the powerpc __builtin_vec_add lowering is incorrect.