llvm-project

e21ee41b - [SCEV] Try to re-use pointer LCSSA phis when expanding SCEVs. (#147824)

[SCEV] Try to re-use pointer LCSSA phis when expanding SCEVs. (#147824) Generalize the code added in https://github.com/llvm/llvm-project/pull/147214 to also support re-using pointer LCSSA phis when expanding SCEVs with AddRecs. A common source of integer AddRecs with pointer bases are runtime checks emitted by LV based on the distance between 2 pointer AddRecs. This improves codegen in some cases when vectorizing and prevents regressions with https://github.com/llvm/llvm-project/pull/142309, which turns some phis into single-entry ones, which SCEV will look through now (and expand the whole AddRec), whereas before it would have to treat the LCSSA phi as SCEVUnknown. Compile-time impact neutral: https://llvm-compile-time-tracker.com/compare.php?from=fd5fc76c91538871771be2c3be2ca3a5f2dcac31&to=ca5fc2b3d8e6efc09f1624a17fdbfbe909f14eb4&stat=instructions:u PR: https://github.com/llvm/llvm-project/pull/147824