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On Sun, 12 Dec 2010 13:09:08 -0500 |
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ross smith <rjsm@×××××.edu> wrote: |
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> Perhaps something along the lines of: If CPU_FLAGS is empty or not defined, |
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> set flags based on the -march and -mtune variables. If CPU_FLAGS is set, |
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> respect what has been set there and ignore the other logic for defaults. |
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-march flags are the lowest common denominator for an architecture. For |
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example, core2 enables MMX, SSE, SSE2, SSE3, and SSSE3 while a Core i7 |
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processor also supports SSE4.1, SSE4.2, and AES instructions. It might be |
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useful to use -march as a base and leave it up to the user to set any |
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additional flags, but I don't see how that is any different than what we have |
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now. |
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In addition it would require us to maintain accurate mappings of what -march |
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enables what flags and deal with the fact that these flags may not exist |
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between gcc versions. It also falls apart with -march=native. |
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-- |
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fonts, gcc-porting, it makes no sense how it makes no sense |
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toolchain, wxwidgets but i'll take it free anytime |
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