[llvm-commits] Edge dominance in the presence of multiple edges between two BB

[Rafael Espíndola]

> The point is that we don't need to share the logic with GVN; if we
> reject this case in the verifier, the existing dominance code is
> sufficient everywhere else.

Unfortunately it is not. While no other value is created at edges in
the LLVM IR, some facts are only true when dominated by and edge. For
example, once we branch on cmp checking that a==42, we can replace a
with 42 in any use dominated by the edge.

Check my followup patch that makes GVN use these functions for some examples.

> -Eli

Cheers,
Rafael