[llvm] [CodeGen] Remove static member function Register::virtReg2Index. NFC (PR #127962)

[Matt Arsenault via llvm-commits]

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@@ -93,7 +93,7 @@ bool WebAssemblyReplacePhysRegs::runOnMachineFunction(MachineFunction &MF) {
             FI->setFrameBaseVreg(VReg);
             LLVM_DEBUG({
               dbgs() << "replacing preg " << PReg << " with " << VReg << " ("
-                     << Register::virtReg2Index(VReg) << ")\n";
+                     << Register(VReg).virtRegIndex() << ")\n";
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arsenm wrote:

This should use printReg 

https://github.com/llvm/llvm-project/pull/127962