On 12/17/2011 11:07 PM, Walter Dnes wrote:
Then I ran "gcc -march=native -Q --help=target" and got a major shock. It's a long output listing of what -march=native thinks about my cpu. Here are some relevant items... -march= core2 -mmmx [disabled] -msse [disabled] -msse2 [disabled] -msse3 [disabled] -mssse3 [disabled] It properly identified the cpu as "core2". But mmx, sse, sse2, sse3 (aka pni), and ssse3 are disabled!!!
The output lies. It's a known issue. Use this instead: echo | gcc -dM -E - -march=native You should see stuff like: #define __MMX__ 1 #define __SSE3__ 1
