[llvm] [AMDGPU] NFC: Provide RPTracker interface for external iterators (PR #93088)

[Matt Arsenault via llvm-commits]

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@@ -517,7 +519,9 @@ void GCNUpwardRPTracker::bumpUpwardPressure(const MachineInstr *MI) {
 
   // Account for register pressure similar to RegPressureTracker::recede().
   RegisterOperands RegOpers;
-  const TargetRegisterInfo *TRI = MRI->getTargetRegisterInfo();
+
+  const SIRegisterInfo *TRI =
+      MI->getMF()->getSubtarget<GCNSubtarget>().getRegisterInfo();
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arsenm wrote:

Shouldn't need to crawl through MI to get o the function? This should be locally available somewhere? 

https://github.com/llvm/llvm-project/pull/93088