[LLVMdev] Mandatory duplicated incoming nodes on phis

[Chris Lattner]

On Aug 27, 2008, at 3:37 AM, Gary Benson wrote:

> Hi,
>
> I noticed that if you create a switch with multiple cases going to
> the same destination, then if that destination contains phis you
> need to add the incoming value an equivalent number of times.  The
> attached code seems wrong, but it compiles as correct, and removing
> the duplicated incoming node causes an error.  Is this expected?

Hi Gary,

I agree that this is somewhat annoying, but it is required to maintain  
the invariant that a phi node in a block has the same number of  
entries as the block has predecessors.

-Chris