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