[PATCH] D139780: [AMDGPU] Unify divergent nodes if the PostDom tree has one root

Tue Jan 3 22:07:42 PST 2023

ruiling added inline comments.

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Comment at: llvm/lib/Target/AMDGPU/AMDGPUUnifyDivergentExitNodes.cpp:109
   // This is a cluster of orthogonal Transforms
   AU.addPreservedID(LowerSwitchID);
   FunctionPass::getAnalysisUsage(AU);
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arsenm wrote:
> ruiling wrote:
> > gandhi21299 wrote:
> > > arsenm wrote:
> > > > We should have a required LowerSwitchID too
> > > I will have a seperate patch for that, it seems to be causing difficulties when the pass manager schedules UnifyDivergentExitNodes.
> > I think for function pass dependency or pass ordering, I still prefer they are managed by compiler developer. If I remember correctly, the new pass manager does not support dependency between function passes?
> The important part is verification. We shouldn't have arbitrary pass contracts not enforced by a verifier
I agree that pass contracts or assumption should be enforced by verification. For this specific issue, can we verify within this pass that a terminator should not be SwitchInst?

Repository:
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CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D139780/new/

https://reviews.llvm.org/D139780