[LLVMdev] Copy Instructions?

[Chris Lattner]

On Jan 28, 2009, at 9:50 AM, David Greene wrote:
>> Why is this a problem?  All phis execute "atomically".  What problem
>> are you seeing in practice?
>
> I'm getting incorrect answers.
>
> How can a set of phis with a dependence execute simultaenously?
> There is only one definition of x and it has to happen before the  
> use of
> x in the phi defining y, doesn't it?

PHIs can't depend on each other.

> Again, how can simultaenous execution of statements with a  
> dependence have any
> meaning?

There is no such thing.

>  For practical reasons, as Owen says, LLVM does not treat phis as
> executing simultaneously.

He's wrong.

-Chris