[clang] [X86] Finally handle target of __builtin_ia32_cmp[p|s][s|d] from avx into sse/sse2/avx (PR #84136)

[Paul T Robinson via cfe-commits]

https://github.com/pogo59 commented:

The example for `\fn` in the [doxygen documentation](https://www.doxygen.nl/manual/commands.html#cmdfn) puts the directive at the top of the comment block, not at the end. Do we know whether putting it at the end will produce the expected result?

https://github.com/llvm/llvm-project/pull/84136