[LLVMdev] Optimization passes and debug info

[Mike Stump]

On Jul 8, 2008, at 3:33 AM, Matthijs Kooijman wrote:
> It would be simple to tell SimplifyCFG, for this particular  
> transformation,
> that a near-empty basic block (which can currently only contain phi  
> nodes and
> a single unconditional branch) can also contain stop points. This  
> would simply
> propagate the phi nodes where needed and throw away the stop point  
> (which
> really can't be propagated anywhere).

Well, technically you can move it back up before the merging and  
transform it to stop and then single step machine instructions until  
it hits the merged point.  One would just need a way to express this  
in the debug info and have a debugger that would do that for you.  :-)