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Currently, I am compiling:

clang -Oz -g

But I would like to apply an -mtune and if possible an -march flag, and anything else that will be valid on all Intel architectures that OS X Leopard supports.

Specifically I am asking: which -mtune and -march flag should I specify so that my binary is optimized for 10.5, and will run on all supported Intel processors for 10.5?

In addition, I would like to apply different tunings to the 32 bit and 64 bit portions, is this possible? If so what should I tune the 64 bit portion to?

For bonus points, I am interested in the same for PowerPC, for future reference, though currently I do not support that.

mxcl
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1 Answers1

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You can build separate binaries using different -march and other flags, though be aware that -march can use instructions not available on earlier processors. -mtune and -mcpu can choose instructions, alignment, etc., that will favour a particular processor, yet run on all processors in that family.

To tune to different architectures (i386, x86-64, ppc, ppc64) you would have to consult the manual pages for clang / gcc. After separate builds it should be possible to use lipo to create a universal binary. There's a simple example here.

For Apple's compilers, you should use the -arch specification, and -mmacosx-version-min=10.5, provided you still have the SDKs for 10.5.

Brett Hale
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