https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86677
Bug ID: 86677 Summary: popcount builtin detection is breaking some kernel build Product: gcc Version: 9.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: target Assignee: unassigned at gcc dot gnu.org Reporter: kugan at gcc dot gnu.org Target Milestone: --- Linux kernel build for arm/aarch64 (and possibly other targets) which does not provide appropriate patterns in the backend will break the kernel build. As for aarch64 this happens because kernel is built with -mgeneral-regs-only Also discussed in: https://gcc.gnu.org/ml/gcc-patches/2018-07/msg00489.html