https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103393
Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Target Milestone|--- |12.0 Ever confirmed|0 |1 Status|UNCONFIRMED |NEW CC| |hjl.tools at gmail dot com Summary|[ 12 Regression ] Auto |[12 Regression] Generating |vectorizer generating |256bit register usage with |256bit register usage with |-mprefer-avx128 |-mprefer-avx128 |-mprefer-vector-width=128 |-mprefer-vector-width=128 | Target| |x86_64-*-* i?86-*-* Last reconfirmed| |2021-11-24 --- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> --- It isn't the vectorizer but memmove inline expansion. I'm not sure it's really a bug, but there isn't a way to disable %ymm use besides disabling AVX entirely. HJ?