[llvm] [InstCombine] Fold copysign of selects from sign comparison to sign operand (PR #85627)

[Nikita Popov via llvm-commits]

nikic wrote:

The copysign is important here. The transform is valid only because only the sign is demanded, you can't do it for all selects. So the root instruction for this transform should be copysign, not select.

https://github.com/llvm/llvm-project/pull/85627