[clang] [llvm] Clang: convert `__m64` intrinsics to unconditionally use SSE2 instead of MMX. (PR #96540)

[Phoebe Wang via cfe-commits]

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+USE_XMM=
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phoebewang wrote:

How about we move these old implementations in to a seperate file (or leave them where they are if you like) and rename them to xxxx_dept, so that we don't rely on old compilers? We can then remove them as well as the tests in the next release.

https://github.com/llvm/llvm-project/pull/96540