[llvm] [AArch64] Convert `CSEL(X, 1)` into `CSINC(X, XZR)` in early-ifcvt (PR #162993)

[Paul Walker via llvm-commits]

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@@ -753,17 +777,17 @@ static unsigned canFoldIntoCSel(const MachineRegisterInfo &MRI, unsigned VReg,
     unsigned ZReg = removeCopies(MRI, DefMI->getOperand(1).getReg());
     if (ZReg != AArch64::XZR && ZReg != AArch64::WZR)
       return 0;
-    SrcOpNum = 2;
+    SrcReg = DefMI->getOperand(2).getReg();
     Opc = Is64Bit ? AArch64::CSNEGXr : AArch64::CSNEGWr;
     break;
   }
   default:
     return 0;
   }
-  assert(Opc && SrcOpNum && "Missing parameters");
+  assert(Opc && SrcReg && "Missing parameters");
 
   if (NewVReg)
-    *NewVReg = DefMI->getOperand(SrcOpNum).getReg();
+    *NewVReg = SrcReg;
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paulwalker-arm wrote:

It's worth renaming NewVReg to NewReg now it's not guaranteed to be a virtual register.

https://github.com/llvm/llvm-project/pull/162993