[PATCH] D137407: [GlobalIsel] Handle carry output generated in narrowScalarAddSub legalize action

[Yashwant Singh via Phabricator via llvm-commits]

yassingh added inline comments.


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Comment at: llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp:5128-5131
+  const TargetRegisterInfo *TRI = MF.getSubtarget().getRegisterInfo();
+  for (MachineInstr &Use : MRI.use_instructions(CarryDst)) {
+    Use.substituteRegister(CarryDst, CarryIn, 0, *TRI);
+  }
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arsenm wrote:
> Changing the uses from here isn't the way the legalizer expects to work. Each instruction is legalized on its own without modifying other instructions, and using intermediate cast operations. The artifact combiner is then responsible for cleaning out illegal intermediate types 
The artifact combiner is not automatically doing this. Can you direct where or how should I modify ArtifactCombiner? 


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D137407/new/

https://reviews.llvm.org/D137407