[llvm] [AMDGPU][Scheduler] Refactor VGPR rematerialization during scheduling (PR #118722)

[Matt Arsenault via llvm-commits]

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@@ -945,20 +950,20 @@ bool PreRARematStage::initGCNSchedStage() {
     return false;
 
   const TargetInstrInfo *TII = MF.getSubtarget().getInstrInfo();
-  // Check maximum occupancy
+  // Rematerialization will not help if occupancy is LDS-limited.
   if (ST.computeOccupancy(MF.getFunction(), MFI.getLDSSize()) ==
       DAG.MinOccupancy)
     return false;
 
   // FIXME: This pass will invalidate cached MBBLiveIns for regions
-  // inbetween the defs and region we sinked the def to. Cached pressure
-  // for regions where a def is sinked from will also be invalidated. Will
-  // need to be fixed if there is another pass after this pass.
+  // inbetween the defs and region we sinked the def to. Will need to be fixed
+  // if there is another pass after this pass.
   assert(!S.hasNextStage());
 
-  collectRematerializableInstructions();
-  if (RematerializableInsts.empty() || !sinkTriviallyRematInsts(ST, TII))
+  std::vector<RematInstruction> RematInstructions;
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arsenm wrote:

Probably should be SmallVector

https://github.com/llvm/llvm-project/pull/118722