[llvm] [ConstraintElim] Add facts about non-poison intrinsics on demand (PR #136558)

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

> I don't really understand the approach you are using here.

If an instruction is guaranteed not to be a poison and not to produce a poison, its operands are also non-poison (except for select). We collect a set of non-poison values used as conditions first, then find the closure of the set with the rule above. Finally we add constraints for non-poison intrinsics.


https://github.com/llvm/llvm-project/pull/136558