https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102404
Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Target|x86_64 |x86_64-*-* Status|UNCONFIRMED |NEW Ever confirmed|0 |1 Last reconfirmed| |2021-09-20 --- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> --- 32 bytes are 256 bits (ymm), 64 bytes are 512 bits (zmm). GCC does not consider zmm vectorization because t.c:25:37: missed: loop does not have enough iterations to support vectorization. because t.c:25:37: note: vectorization_factor = 16, niters = 8 the memory accesses cannot be related so we fail to SLP this. Does clang use vpgathers/scatters on %zmm here?