[llvm-commits] [llvm] r85016 - /llvm/trunk/lib/Transforms/Scalar/LoopRotation.cpp

[Sylvere Teissier]

Dan Gohman a écrit :
> 
> One problem I'm seeing is redundant PHIs. Sphereflake for example
> now gets code like this:
> 
>    %p.013.i = phi %struct.node_t* [ %p.0.be.i, %bb5.backedge.i ],  
> [ %78, %bb9.i ] ; <%struct.node_t*> [#uses=1]
>    %p.012.i = phi %struct.node_t* [ %p.0.be.i, %bb5.backedge.i ],  
> [ %78, %bb9.i ] ; <%struct.node_t*> [#uses=1]
>    %p.011.i = phi %struct.node_t* [ %p.0.be.i, %bb5.backedge.i ],  
> [ %78, %bb9.i ] ; <%struct.node_t*> [#uses=1]
>    %p.010.i = phi %struct.node_t* [ %p.0.be.i, %bb5.backedge.i ],  
> [ %78, %bb9.i ] ; <%struct.node_t*> [#uses=1]
>    %p.09.i = phi %struct.node_t* [ %p.0.be.i, %bb5.backedge.i ],  
> [ %78, %bb9.i ] ; <%struct.node_t*> [#uses=7]
> 
> Indvars can't eliminate these because they aren't a function of the
> canonical induction variable.   These PHIs stick around and end up
> being allocated registers, which is suboptimal.
> 

Any news about this problem ?
Do I need to create a bug report ?

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