[Bug target/115362] fixed_size_simd dot product recognition and sign of determinant not working for stdx::reduce

[jondaniel879 at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115362

--- Comment #11 from Jon Daniel <jondaniel879 at gmail dot com> ---
g++ output:

dot_product stdx::reduce: -16.000000
dot_product    _mm_dp_ps: -16.000000
determinant: dot_product: 717.000000
determinant: submatrices: -717.000000

clang++ output:

dot_product stdx::reduce: -16.000000
dot_product    _mm_dp_ps: -16.000000
determinant: dot_product: -717.000000
determinant: submatrices: -717.000000