[PATCH] D70597: [PHIEliminate] skip dbg instruction when LowerPHINode

Wed Dec 4 16:41:10 PST 2019

yechunliang added a comment.

In D70597#1769185 <https://reviews.llvm.org/D70597#1769185>, @jmorse wrote:

> In D70597#1768869 <https://reviews.llvm.org/D70597#1768869>, @yechunliang wrote:
>
> > Another idea is to add one more helper like getFirstNonPHIsAndLabels(), replace getFirstNonPHI in ScheduleDAGSDNodes.cpp#L935.
> >  Insert dbg_values after PHIs and Labels, so that there will be no dbg_values barrier between PHI and LABELS.
>
>
> This sounds good to me -- there's an existing "SkipPHIsLabelsAndDebug" method in MachineBasicBlock, would that be sufficient?
>
> Not creating this scenario in the first place sounds is a good plan.

Yes, SkipPHIsAndLabels is workable as below,
MachineBasicBlock::iterator BBBegin = BB->SkipPHIsAndLabels(BB->begin());

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D70597/new/

https://reviews.llvm.org/D70597