[llvm] GlobalISel: adapt MachineSSAUpdater for use in GlobalISel path (PR #78431)

[Matt Arsenault via llvm-commits]

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@@ -40,8 +40,8 @@ class MachineSSAUpdater {
   //typedef DenseMap<MachineBasicBlock*, Register> AvailableValsTy;
   void *AV = nullptr;
 
-  /// VRC - Register class of the current virtual register.
-  const TargetRegisterClass *VRC = nullptr;
+  /// RegAttrs - current virtual register, new registers copy its attributes.
+  Register RegAttrs;
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arsenm wrote:

Relying on an existing register (which may mutate?) may be cumbersome. Maybe would be better to store the RegClassOrRegBank + LLT?

https://github.com/llvm/llvm-project/pull/78431