[llvm] [NewPM][CodeGen] Port MachineLICM to NPM (PR #107376)

[Matt Arsenault via llvm-commits]

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@@ -352,6 +386,11 @@ bool MachineLICMBase::runOnMachineFunction(MachineFunction &MF) {
   MRI = &MF.getRegInfo();
   SchedModel.init(&ST);
 
+  // FIXME: Remove this assignment or convert to an assert?
+  // MachineLICM and PostRAMachineLICM were distinguished by introducing
+  // EarlyMachineLICM and MachineLICM respectively to avoid "using an unreliable
+  // MRI::isSSA() check to determine whether register allocation has happened"
+  // (See 4a7c8e7).
   PreRegAlloc = MRI->isSSA();
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arsenm wrote:

It's not an unreliable check 

https://github.com/llvm/llvm-project/pull/107376