[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:

The problem is then you can't properly serialize the MIR. If your testcase depends on the IPRA state, -start-before to run the RA pipeline does not work 

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