https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65950
Gian-Carlo Pascutto <gcp at sjeng dot org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |gcp at sjeng dot org --- Comment #6 from Gian-Carlo Pascutto <gcp at sjeng dot org> --- I'm seeing similar behavior in gcc-4.9.2 (debian stable) and gcc-5.3.1 (Ubuntu 16.04 prelease). Adding -flto causes certain loops not to get vectorized, adding -fno-lto to affected files fixes it. Unfortunately producing a reduced testcase is not so easy, but program source is available to gcc devs on request.