cmake: don't auto vectorize with AltiVec on PPC #13321
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Allowing GCC/Clang to auto-vectorize with AltiVec support breaks support for non-AltiVec compatible processors. Adding this option allows the existing AltiVec specific code to function as it always did, but prevents the compiler from inserting AltiVec instructions into arbitrary codepaths that SDL can't gate off via the existing CPUInfo code.
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Hmm...I think this is probably okay, because it fits the spirit of what that piece of CMake code is trying to do, and historically we've had to deal with (Apple) computers that might or might not have AltiVec support. But for systems with guaranteed AltiVec units, we probably do want the compiler to use those instructions wherever it can, even just in basic for-loops outside of the blitters. Unlike the Mac, I assume most PowerPC systems are special case devices that you build specific binaries for. So I think merge this, but let's add a FIXME to maybe adjust this at some point. |
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Description
Allowing GCC/Clang to auto-vectorize with AltiVec support breaks support for non-AltiVec compatible processors. Adding this option allows the existing AltiVec specific code to function as it always did, but prevents the compiler from inserting AltiVec instructions into arbitrary codepaths that SDL can't gate off via the existing CPUInfo code.
Existing Issue(s)
None found.