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

[Matt Arsenault via Phabricator via llvm-commits]

arsenm 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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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 


Repository:
  rG LLVM Github Monorepo

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

https://reviews.llvm.org/D137407