llvm-project

b2fe5d14 - [SimplifyCFG] Hoist common code when succ is unreachable block (#165570)

[SimplifyCFG] Hoist common code when succ is unreachable block (#165570) Previously, `hoistCommonCodeFromSuccessors` returned early if one of the succ of BB has >1 predecessors. However, if the succ is an unreachable BB, we can relax the condition to perform `hoistCommonCodeFromSuccessors` based on the assumption of not reaching UB. See discussion https://github.com/dtcxzyw/llvm-opt-benchmark/pull/2989 for details. Alive2 proof: https://alive2.llvm.org/ce/z/OJOw0s Promising optimization impact: https://github.com/dtcxzyw/llvm-opt-benchmark/pull/2995