[llvm] Use range attribute to constant fold comparisons with constant values. (PR #84627)

[Andreas Jonson via llvm-commits]

andjo403 wrote:

> It might make sense to add getRange() on Argument/CallBase, which always returns a ConstantRange, using Full range if attribute is not present. 

it feels a bit strange maybe when the argument/result is e.g. a pointer typ, what shall the bit width be for the Full range in that case?

https://github.com/llvm/llvm-project/pull/84627