[PATCH] D38789: MachineInstr: Force isDef to match in isIdenticalTo

[Krzysztof Parzyszek via Phabricator via llvm-commits]

kparzysz added a comment.

Here's a comment from `include/llvm/CodeGen/MachineInstr.h` (definition of `MachineInstrExpressionTrait`)

  /// Special DenseMapInfo traits to compare MachineInstr* by *value* of the
  /// instruction rather than by pointer value.
  /// The hashing and equality testing functions ignore definitions so this is
  /// useful for CSE, etc.

The `isEqual` function explicitly requests `IgnoreVRegDefs`, supposedly on the basis that `getHashValue` would do the same.  Your observation is that this is not the case.  Assuming that this comment was true at some point, it may be worthwhile to check how the deviation was introduced.


https://reviews.llvm.org/D38789