http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50740
Bug #: 50740 Summary: CPUID leaf 7 for BMI/BMI2/AVX2 feature detection not qualified with max_level and doesn't use subleaf Classification: Unclassified Product: gcc Version: unknown Status: UNCONFIRMED Severity: normal Priority: P3 Component: driver AssignedTo: unassig...@gcc.gnu.org ReportedBy: craig.top...@gmail.com The cpuid code for detecting BMI, BMI2, and AVX2 support needs to be qualified with max_level >= 7. Additionally, it should use __cpuid_count instead of __cpuid because leaf 7 uses subleafs just like leaf 4. Relevant code from i386-driver.c __cpuid (0x7, eax, ebx, ecx, edx); has_bmi = ebx & bit_BMI; has_avx2 = ebx & bit_AVX2; has_bmi2 = ebx & bit_BMI2;