[llvm] LICM: extend hoistAddSub to unsigned case (PR #106373)

[Nikita Popov via llvm-commits]

https://github.com/nikic commented:

> Alive2 proofs: test_01_unsigned: https://alive2.llvm.org/ce/z/GXJ39G test_02_unsigned: https://alive2.llvm.org/ce/z/xWmcnT test_03_unsigned: https://alive2.llvm.org/ce/z/P9Bt4J test_04_unsigned: https://alive2.llvm.org/ce/z/AxBZ9R

For proofs it would be more useful to only prove the performed reassociation, without the loop, which is not really relevant here. It's easy to get false positive proofs when loops are involved.

Also, the proofs should encode the preconditions generically (e.g. using with.overflow intrinsics), not hardcode specific values.

https://github.com/llvm/llvm-project/pull/106373