[llvm] [IPSCCP] Add range attribute handling. (PR #86747)

[Antonio Frighetto via llvm-commits]

https://github.com/antoniofrighetto approved this pull request.

LGTM, `markConstantRange` implementation looks good. Let's wait for `@nikic` as well when he's back though.

https://github.com/llvm/llvm-project/pull/86747