[all-commits] [llvm/llvm-project] 0b4a4c: [IndVarSimplify] Forget phi value after changing i...

[Florian Hahn via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 0b4a4cc72d81a522230a7270abdfa804aa49d89b
      https://github.com/llvm/llvm-project/commit/0b4a4cc72d81a522230a7270abdfa804aa49d89b
  Author: Florian Hahn <flo at fhahn.com>
  Date:   2021-09-29 (Wed, 29 Sep 2021)

  Changed paths:
    M llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
    A llvm/test/Transforms/IndVarSimplify/invalidate-modified-lcssa-phi.ll

  Log Message:
  -----------
  [IndVarSimplify] Forget phi value after changing incoming value.

This fixes an issue exposed by D71539, where IndVarSimplify tries
to access an invalid cached SCEV expression after making changes to the
underlying PHI instruction earlier.

When changing the incoming value of a PHI, forget the cached SCEV for
the PHI.