[PATCH] D108830: [AMDGPU] Propagate defining src reg for AGPR to AGPR Copys

[Stanislav Mekhanoshin via Phabricator via llvm-commits]

rampitec added inline comments.


================
Comment at: llvm/lib/Target/AMDGPU/GCNPreRAOptimizations.cpp:101
+      // accvgpr_write to avoid temporary registers.
+      Register DstReg = I.getOperand(0).getReg();
+      Register SrcReg = I.getOperand(1).getReg();
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rampitec wrote:
> You know you are dealing with an AGPR or SGPR right at the beginning of the function. You can quickly bail from here based on that.
DstReg always the same as Reg or at least should be unless it is not an implicit-def. At maximum I would expect assert(Reg == I.getOperand(0).getReg()) here.


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Comment at: llvm/lib/Target/AMDGPU/GCNPreRAOptimizations.cpp:104
+
+      if (!Reg.isVirtual() || !SrcReg.isVirtual())
+        break;
----------------
Reg is always virtual, it is a result of index2VirtReg() call.


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CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D108830/new/

https://reviews.llvm.org/D108830