Add detection of function multi-versioning in the compiler #234
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This support is used so that the SSE2 version of memcpy_nontemporal is selected only if the CPU supports SSE2 at runtime. On x86-64 there is guaranteed to be runtime support, so this only affects i386. Note that i386 is not currently tested. The real motivation is that it lays the groundwork for adding more specialised variants e.g. AVX, AVX-512, MOVDIR64B etc.
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@james-smith-za I think hold off the reviewing for now - it's going to need some tweaks to make it play nice with MacOS's universal binaries. |
Why we are bothering to support macOS is still beyond me... Does the Apple silicon even support SSE2? |
Some applications that use spead2 are developed by people who have Macs (like @ludwigschwardt).
It doesn't. But the Python builder tries to build universal binaries that have code for both x86-64 and ARM64, which confuses things. |
Never use it on non-x86 architectures. This is a workaround for MacOS universal binary Python builds, where detection happens on x86 but the ARM branch of the build fails because it's not supported there.
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@james-smith-za looks like I've got the MacOS support fixed. |
To further support this point: in SKA there are several developers that use Macs and either indirectly use spead2, or actually develop applications on top of it. |
This support is used so that the SSE2 version of memcpy_nontemporal is selected only if the CPU supports SSE2 at runtime.
On x86-64 there is guaranteed to be runtime support, so this only affects i386. Note that i386 is not currently tested. The real motivation is that it lays the groundwork for adding more specialised variants e.g. AVX, AVX-512, MOVDIR64B etc.