https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79932
Bug ID: 79932 Summary: _mm512_packus_epi32 does not compile under -O0 Product: gcc Version: 6.2.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: target Assignee: unassigned at gcc dot gnu.org Reporter: carloscastro10 at hotmail dot com Target Milestone: --- The _mm512_packus_epi32 intrinsic compiles fine under -Og, -O2, -O3, but does not compile under -O0. For a simple example consider the following code: #include <immintrin.h> __m512i packus(__m512i a) { return _mm512_packus_epi32(a,a); } Try compiling with "-march=skylake-avx512 -O0". It will fail. However, under -Og, -O2, or -O3 it will compile fine.