[Bug target/87077] missed optimization for horizontal add for x86 SSE

[glisse at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87077

--- Comment #1 from Marc Glisse <glisse at gcc dot gnu.org> ---
SLP doesn't like the completely unrolled code. With #pragma GCC unroll 1, we
get at least some kind of vectorization.