[PATCH] D99032: GlobalISel: Add FoldBinOpIntoSelect combine

Jessica Paquette via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Mon Mar 22 17:39:33 PDT 2021


paquette added inline comments.


================
Comment at: llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp:3365
+  Register RHS = MI.getOperand(2).getReg();
+  MachineInstr *Select = MRI.getVRegDef(MI.getOperand(SelectOperand).getReg());
+
----------------
In the match function, you found the G_SELECT using `getOpcodeDef`, which walks through COPY instructions. If that walked through a COPY, I think this will give you the wrong instruction.


================
Comment at: llvm/lib/CodeGen/GlobalISel/Utils.cpp:882
+  const unsigned Opcode = MI.getOpcode();
+  if (!isBuildVectorOp(Opcode))
+    return false;
----------------
Opcode is only used here?


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D99032/new/

https://reviews.llvm.org/D99032



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