[clang] [llvm] [DropUnnecessaryAssumes] Add pass for dropping assumes (PR #159403)

[Nikita Popov via llvm-commits]

nikic wrote:

> Could a possible follow-up drop identical assumes? If so, would it be possible to schedule this pass late? We see some redundant identical assumes in LV.

The responsibility for removing redundant assumes falls largely to InstCombine, and to a lesser degree other passes that propagate assumes (like GVN, SCCP).

https://github.com/llvm/llvm-project/pull/159403