[llvm] [CodeGen][NewPM] Port RegisterUsageInfo to NPM (PR #113873)

[Matt Arsenault via llvm-commits]

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@@ -66,6 +63,52 @@ class PhysicalRegisterUsageInfo : public ImmutablePass {
   const LLVMTargetMachine *TM = nullptr;
 };
 
+class PhysicalRegisterUsageInfoWrapperLegacy : public ImmutablePass {
+  std::unique_ptr<PhysicalRegisterUsageInfo> PRUI;
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arsenm wrote:

No. I mean this analysis largely serves just as a place to hold allocated regmasks. There is a parallel mechanism for storing custom register masks in MachineRegisterInfo already. We need to consolidate these, and improve the serialization for them (i.e. introduce some kind of printed MachineFunction section for contained regmasks with an ID that the instructions can refer to them by inline, otherwise we'll have hundreds of lines printed for every call instruction) 

https://github.com/llvm/llvm-project/pull/113873