[PATCH] D124678: [AMDGPU] Allow for MFMA Inst Clustering

[Austin Kerbow via Phabricator via llvm-commits]

kerbowa added inline comments.


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Comment at: llvm/lib/Target/AMDGPU/AMDGPUSubtarget.cpp:856
+      if (!TII->isMAI(MAI) ||
+          MAI.getOpcode() == AMDGPU::V_ACCVGPR_WRITE_B32_e64 ||
+          MAI.getOpcode() == AMDGPU::V_ACCVGPR_READ_B32_e64)
----------------
jrbyrnes wrote:
> rampitec wrote:
> > kerbowa wrote:
> > > arsenm wrote:
> > > > What about copies before they are lowered to accvgpr_write?
> > > I guess isMAI above would handle that?
> > They are not MAI. This ideom used to filter MFMA from 2 other MAI encoded instructions.
> Thanks for your comments. I looked into it, and these types of copies are not flagged as MAI to begin with -- the check to exclude accvgpr_write is thus irrelevant.
I'm not sure, I think it will be flagged. We use this idiom enough that we really should just add an isMFMA function to siinstrinfo.


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Comment at: llvm/lib/Target/AMDGPU/AMDGPUSubtarget.cpp:898
+        if (MFMAOpa->NodeNum > MFMAOpb->NodeNum)
+          std::swap(MFMAOpa, MFMAOpb);
+
----------------
rampitec wrote:
> What if one feeds another and you swap them?
This is only looking at independent MFMA.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D124678/new/

https://reviews.llvm.org/D124678