[llvm] [CodeGen] Teach ReplaceWithVeclib split vector llvm.sincos when only sin/cos veclib mappings exist (PR #194639)

[Kito Cheng via llvm-commits]

kito-cheng wrote:

> Thanks, lgtm.
> 
> > The one of the common case is glibc libmvec on x86: it exposes `_ZGV{b,c,d,e}N{2,4,8,16}vvv_sincos{,f}` symbols
> 
> What about `_ZGV{b,c,d,e}N{2,4,8,16}{vl8l8_sincos,vl4l4_sincosf}`? I don't know why they aren't exported from libmvec.so, but they do exist in libmvec.a.

https://sourceware.org/git/?p=glibc.git;a=commit;h=92deb83907f771dc38614628c60309bb7ea84511

Seems like it's *wrong* vector ABI implementation so that isn't exported anymore, I guess right way to resolve this might be implement that ABI support in LLVM, but I might left that to other one who interested.

https://github.com/llvm/llvm-project/pull/194639