[PATCH] D28193: NewGVN: Add UnknownExpression and create them for things we can't symbolize. Kill fragile machinery for handling null expressions.

[Daniel Berlin via Phabricator via llvm-commits]

dberlin marked an inline comment as done.
dberlin added a comment.

The testcase we'd want, i think, is to have an invoke and a catchswitch that both return values.
Previously, it should have considered them the same value, i think.

I actually discovered that part while looking at this comment:

  // FIXME: We should eventually be able to replace everything still
  // in the initial class with undef, as they should be unreachable.
  // Right now, initial still contains some things we skip value
  // numbering of (UNREACHABLE's, for example)."

it contained a few invoke's, so i went hunting why.


https://reviews.llvm.org/D28193