[llvm] [LV] Teach the vectorizer to cost and vectorize llvm.sincos intrinsics (PR #123210)

[David Sherwood via llvm-commits]

https://github.com/david-arm commented:

Given you've got explicit cost model tests in llvm/test/Analysis/CostModel/AArch64/sincos.ll for the BasicTTIImpl changes I wonder if it's worth pulling the vectoriser changes out into a follow-on PR? That way you at least get to keep most of the changes upstream if the vectoriser bits get reverted for some reason.

https://github.com/llvm/llvm-project/pull/123210