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

[Rafael Espíndola]

> define i32 @f(i32 %i) {
> bb0:
>   switch i32 %i, label %bb1 [
>     i32 1, label %bb2
>     i32 2, label %bb2
>   ]
> bb1:
>   br label %bb2
> bb2:
>   %r = phi i32 [ 1, %bb0 ], [ 2, %bb0 ], [ 5, %bb1 ]
>   ret i32 %r
> }

I found out that the verifier rejects this:

PHI node has multiple entries for the same basic block with different
incoming values!

Which suggests that we can use a simpler definition of edge dominance
that simply checks if there are multiple edges between two basic
blocks. An updated patch is attached.

Cheers,
Rafael
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