[llvm] [SimplifyLibCalls] Simplify cabs libcall if real or imaginary part of input is zero (PR #97976)

[Hendrik Hübner via llvm-commits]

HendrikHuebner wrote:

> IIRC `ConstantFolder::FoldExtractValue` should handle this case. You can just push the array tests then I can have a look :)

Hmm... I dont think the array is a constant when it is passed to the cabs function. So this probably means its not so trivial to check whether one of its elements is constant..? In that case I will skip the optimization for array inputs.

https://github.com/llvm/llvm-project/pull/97976