[llvm] [CodeGen] Add listener support to the rematerializer (NFC) (PR #184338)

[Lucas Ramirez via llvm-commits]

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@@ -574,9 +577,10 @@ RegisterIdx Rematerializer::getDefRegIdx(const MachineInstr &MI) const {
 RegisterIdx Rematerializer::rematerializeReg(
     RegisterIdx RegIdx, MachineBasicBlock::iterator InsertPos,
     SmallVectorImpl<Reg::Dependency> &&Dependencies) {
-  unsigned UseRegion = MIRegion.at(&*InsertPos);
   RegisterIdx NewRegIdx = Regs.size();
+  notifyListeners(&Listener::beforeRegRematerialized, RegIdx, NewRegIdx);
 
+  unsigned UseRegion = MIRegion.at(&*InsertPos);
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lucas-rami wrote:

It has a few uses in the function.

https://github.com/llvm/llvm-project/pull/184338