[all-commits] [llvm/llvm-project] ccf788: [IRCE] Drop SCEV of a Phi after adding a new input...

[Max Kazantsev via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: ccf788a5659430571d5970dfc766b235e413dde2
      https://github.com/llvm/llvm-project/commit/ccf788a5659430571d5970dfc766b235e413dde2
  Author: Max Kazantsev <mkazantsev at azul.com>
  Date:   2022-08-25 (Thu, 25 Aug 2022)

  Changed paths:
    M llvm/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp
    A llvm/test/Transforms/IRCE/pr57335.ll

  Log Message:
  -----------
  [IRCE] Drop SCEV of a Phi after adding a new input. PR57335

Since SCEV learned to look through single value phis with
20d798bd47ec5191de1b2a8a031da06a04e612e1, whenever we add
a new input to a Phi, we should make sure that the old cached
value is dropped. Otherwise, it may lead to various miscompiles,
such as breach of dominance as shown in the bug
https://github.com/llvm/llvm-project/issues/57335