Function matmul_row_dispatch 

pub unsafe fn matmul_row_dispatch(
    left_row: *const f32,
    right: *const f32,
    out_row: *mut f32,
    k: usize,
    n: usize,
)

Dispatch to the best available SIMD path for a single matmul output row.

Safety

• left_row must point to at least k valid f32 elements.
• right must point to at least k * n valid f32 elements (row-major B).
• out_row must point to at least n valid f32 elements.
• The caller must ensure no aliasing between out_row and the input pointers.