https://gcc.gnu.org/bugzilla/show_bug.cgi?id=127452
--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> --- The promised late rewrite to scalar MULT_HIGHPART_EXPR happens, but we seem to prefer generating imul over mulx. even though x86 has imul over mulx even with explicit -mbmi2 - that might be a target thing though, we do not seem to have direct scalar 64bit mulh expanders?
