diff --git a/llvm/include/llvm/CodeGen/MachineScheduler.h b/llvm/include/llvm/CodeGen/MachineScheduler.h
index efda7eb8ffc8d..5a2aee2fa7643 100644
--- a/llvm/include/llvm/CodeGen/MachineScheduler.h
+++ b/llvm/include/llvm/CodeGen/MachineScheduler.h
@@ -1303,8 +1303,8 @@ class LLVM_ABI GenericScheduler : public GenericSchedulerBase {
   SchedBoundary Top;
   SchedBoundary Bot;
 
-  ClusterInfo *TopCluster;
-  ClusterInfo *BotCluster;
+  unsigned TopClusterID;
+  unsigned BotClusterID;
 
   /// Candidate last picked from Top boundary.
   SchedCandidate TopCand;
@@ -1346,8 +1346,8 @@ class LLVM_ABI PostGenericScheduler : public GenericSchedulerBase {
   /// Candidate last picked from Bot boundary.
   SchedCandidate BotCand;
 
-  ClusterInfo *TopCluster;
-  ClusterInfo *BotCluster;
+  unsigned TopClusterID;
+  unsigned BotClusterID;
 
 public:
   PostGenericScheduler(const MachineSchedContext *C)
diff --git a/llvm/include/llvm/CodeGen/ScheduleDAG.h b/llvm/include/llvm/CodeGen/ScheduleDAG.h
index 3a0a31b1930b0..122b7be96b46a 100644
--- a/llvm/include/llvm/CodeGen/ScheduleDAG.h
+++ b/llvm/include/llvm/CodeGen/ScheduleDAG.h
@@ -240,6 +240,11 @@ class TargetRegisterInfo;
   typedef SmallSet<SUnit *, 8> ClusterInfo;
   constexpr unsigned InvalidClusterId = ~0u;
 
+  /// Return whether the input cluster ID's are the same and valid.
+  inline bool isTheSameCluster(unsigned A, unsigned B) {
+    return A != InvalidClusterId && A == B;
+  }
+
   /// Scheduling unit. This is a node in the scheduling DAG.
   class SUnit {
   private:
diff --git a/llvm/lib/CodeGen/MachineScheduler.cpp b/llvm/lib/CodeGen/MachineScheduler.cpp
index 9d5c39ce7ae76..c6fa8f42757db 100644
--- a/llvm/lib/CodeGen/MachineScheduler.cpp
+++ b/llvm/lib/CodeGen/MachineScheduler.cpp
@@ -3676,8 +3676,8 @@ void GenericScheduler::initialize(ScheduleDAGMI *dag) {
   TopCand.SU = nullptr;
   BotCand.SU = nullptr;
 
-  TopCluster = nullptr;
-  BotCluster = nullptr;
+  TopClusterID = InvalidClusterId;
+  BotClusterID = InvalidClusterId;
 }
 
 /// Initialize the per-region scheduling policy.
@@ -3988,10 +3988,14 @@ bool GenericScheduler::tryCandidate(SchedCandidate &Cand,
   // This is a best effort to set things up for a post-RA pass. Optimizations
   // like generating loads of multiple registers should ideally be done within
   // the scheduler pass by combining the loads during DAG postprocessing.
-  const ClusterInfo *CandCluster = Cand.AtTop ? TopCluster : BotCluster;
-  const ClusterInfo *TryCandCluster = TryCand.AtTop ? TopCluster : BotCluster;
-  if (tryGreater(TryCandCluster && TryCandCluster->contains(TryCand.SU),
-                 CandCluster && CandCluster->contains(Cand.SU), TryCand, Cand,
+  unsigned CandZoneCluster = Cand.AtTop ? TopClusterID : BotClusterID;
+  unsigned TryCandZoneCluster = TryCand.AtTop ? TopClusterID : BotClusterID;
+  bool CandIsClusterSucc =
+      isTheSameCluster(CandZoneCluster, Cand.SU->ParentClusterIdx);
+  bool TryCandIsClusterSucc =
+      isTheSameCluster(TryCandZoneCluster, TryCand.SU->ParentClusterIdx);
+
+  if (tryGreater(TryCandIsClusterSucc, CandIsClusterSucc, TryCand, Cand,
                  Cluster))
     return TryCand.Reason != NoCand;
 
@@ -4251,24 +4255,30 @@ void GenericScheduler::reschedulePhysReg(SUnit *SU, bool isTop) {
 void GenericScheduler::schedNode(SUnit *SU, bool IsTopNode) {
   if (IsTopNode) {
     SU->TopReadyCycle = std::max(SU->TopReadyCycle, Top.getCurrCycle());
-    TopCluster = DAG->getCluster(SU->ParentClusterIdx);
-    LLVM_DEBUG(if (TopCluster) {
-      dbgs() << "  Top Cluster: ";
-      for (auto *N : *TopCluster)
-        dbgs() << N->NodeNum << '\t';
-      dbgs() << '\n';
+    TopClusterID = SU->ParentClusterIdx;
+    LLVM_DEBUG({
+      if (TopClusterID != InvalidClusterId) {
+        ClusterInfo *TopCluster = DAG->getCluster(TopClusterID);
+        dbgs() << "  Top Cluster: ";
+        for (auto *N : *TopCluster)
+          dbgs() << N->NodeNum << '\t';
+        dbgs() << '\n';
+      }
     });
     Top.bumpNode(SU);
     if (SU->hasPhysRegUses)
       reschedulePhysReg(SU, true);
   } else {
     SU->BotReadyCycle = std::max(SU->BotReadyCycle, Bot.getCurrCycle());
-    BotCluster = DAG->getCluster(SU->ParentClusterIdx);
-    LLVM_DEBUG(if (BotCluster) {
-      dbgs() << "  Bot Cluster: ";
-      for (auto *N : *BotCluster)
-        dbgs() << N->NodeNum << '\t';
-      dbgs() << '\n';
+    BotClusterID = SU->ParentClusterIdx;
+    LLVM_DEBUG({
+      if (BotClusterID != InvalidClusterId) {
+        ClusterInfo *BotCluster = DAG->getCluster(BotClusterID);
+        dbgs() << "  Bot Cluster: ";
+        for (auto *N : *BotCluster)
+          dbgs() << N->NodeNum << '\t';
+        dbgs() << '\n';
+      }
     });
     Bot.bumpNode(SU);
     if (SU->hasPhysRegDefs)
@@ -4306,8 +4316,8 @@ void PostGenericScheduler::initialize(ScheduleDAGMI *Dag) {
   if (!Bot.HazardRec) {
     Bot.HazardRec = DAG->TII->CreateTargetMIHazardRecognizer(Itin, DAG);
   }
-  TopCluster = nullptr;
-  BotCluster = nullptr;
+  TopClusterID = InvalidClusterId;
+  BotClusterID = InvalidClusterId;
 }
 
 void PostGenericScheduler::initPolicy(MachineBasicBlock::iterator Begin,
@@ -4373,10 +4383,14 @@ bool PostGenericScheduler::tryCandidate(SchedCandidate &Cand,
     return TryCand.Reason != NoCand;
 
   // Keep clustered nodes together.
-  const ClusterInfo *CandCluster = Cand.AtTop ? TopCluster : BotCluster;
-  const ClusterInfo *TryCandCluster = TryCand.AtTop ? TopCluster : BotCluster;
-  if (tryGreater(TryCandCluster && TryCandCluster->contains(TryCand.SU),
-                 CandCluster && CandCluster->contains(Cand.SU), TryCand, Cand,
+  unsigned CandZoneCluster = Cand.AtTop ? TopClusterID : BotClusterID;
+  unsigned TryCandZoneCluster = TryCand.AtTop ? TopClusterID : BotClusterID;
+  bool CandIsClusterSucc =
+      isTheSameCluster(CandZoneCluster, Cand.SU->ParentClusterIdx);
+  bool TryCandIsClusterSucc =
+      isTheSameCluster(TryCandZoneCluster, TryCand.SU->ParentClusterIdx);
+
+  if (tryGreater(TryCandIsClusterSucc, CandIsClusterSucc, TryCand, Cand,
                  Cluster))
     return TryCand.Reason != NoCand;
   // Avoid critical resource consumption and balance the schedule.
@@ -4575,11 +4589,11 @@ SUnit *PostGenericScheduler::pickNode(bool &IsTopNode) {
 void PostGenericScheduler::schedNode(SUnit *SU, bool IsTopNode) {
   if (IsTopNode) {
     SU->TopReadyCycle = std::max(SU->TopReadyCycle, Top.getCurrCycle());
-    TopCluster = DAG->getCluster(SU->ParentClusterIdx);
+    TopClusterID = SU->ParentClusterIdx;
     Top.bumpNode(SU);
   } else {
     SU->BotReadyCycle = std::max(SU->BotReadyCycle, Bot.getCurrCycle());
-    BotCluster = DAG->getCluster(SU->ParentClusterIdx);
+    BotClusterID = SU->ParentClusterIdx;
     Bot.bumpNode(SU);
   }
 }
diff --git a/llvm/lib/Target/AMDGPU/GCNSchedStrategy.cpp b/llvm/lib/Target/AMDGPU/GCNSchedStrategy.cpp
index a6553083d722b..b7622d143dabd 100644
--- a/llvm/lib/Target/AMDGPU/GCNSchedStrategy.cpp
+++ b/llvm/lib/Target/AMDGPU/GCNSchedStrategy.cpp
@@ -592,10 +592,13 @@ bool GCNMaxILPSchedStrategy::tryCandidate(SchedCandidate &Cand,
   // This is a best effort to set things up for a post-RA pass. Optimizations
   // like generating loads of multiple registers should ideally be done within
   // the scheduler pass by combining the loads during DAG postprocessing.
-  const ClusterInfo *CandCluster = Cand.AtTop ? TopCluster : BotCluster;
-  const ClusterInfo *TryCandCluster = TryCand.AtTop ? TopCluster : BotCluster;
-  if (tryGreater(TryCandCluster && TryCandCluster->contains(TryCand.SU),
-                 CandCluster && CandCluster->contains(Cand.SU), TryCand, Cand,
+  unsigned CandZoneCluster = Cand.AtTop ? TopClusterID : BotClusterID;
+  unsigned TryCandZoneCluster = TryCand.AtTop ? TopClusterID : BotClusterID;
+  bool CandIsClusterSucc =
+      isTheSameCluster(CandZoneCluster, Cand.SU->ParentClusterIdx);
+  bool TryCandIsClusterSucc =
+      isTheSameCluster(TryCandZoneCluster, TryCand.SU->ParentClusterIdx);
+  if (tryGreater(TryCandIsClusterSucc, CandIsClusterSucc, TryCand, Cand,
                  Cluster))
     return TryCand.Reason != NoCand;
 
@@ -666,10 +669,13 @@ bool GCNMaxMemoryClauseSchedStrategy::tryCandidate(SchedCandidate &Cand,
 
   // MaxMemoryClause-specific: We prioritize clustered instructions as we would
   // get more benefit from clausing these memory instructions.
-  const ClusterInfo *CandCluster = Cand.AtTop ? TopCluster : BotCluster;
-  const ClusterInfo *TryCandCluster = TryCand.AtTop ? TopCluster : BotCluster;
-  if (tryGreater(TryCandCluster && TryCandCluster->contains(TryCand.SU),
-                 CandCluster && CandCluster->contains(Cand.SU), TryCand, Cand,
+  unsigned CandZoneCluster = Cand.AtTop ? TopClusterID : BotClusterID;
+  unsigned TryCandZoneCluster = TryCand.AtTop ? TopClusterID : BotClusterID;
+  bool CandIsClusterSucc =
+      isTheSameCluster(CandZoneCluster, Cand.SU->ParentClusterIdx);
+  bool TryCandIsClusterSucc =
+      isTheSameCluster(TryCandZoneCluster, TryCand.SU->ParentClusterIdx);
+  if (tryGreater(TryCandIsClusterSucc, CandIsClusterSucc, TryCand, Cand,
                  Cluster))
     return TryCand.Reason != NoCand;
 
diff --git a/llvm/lib/Target/PowerPC/PPCMachineScheduler.cpp b/llvm/lib/Target/PowerPC/PPCMachineScheduler.cpp
index 5eb1f0128643d..b7e2263424863 100644
--- a/llvm/lib/Target/PowerPC/PPCMachineScheduler.cpp
+++ b/llvm/lib/Target/PowerPC/PPCMachineScheduler.cpp
@@ -100,10 +100,14 @@ bool PPCPreRASchedStrategy::tryCandidate(SchedCandidate &Cand,
   // This is a best effort to set things up for a post-RA pass. Optimizations
   // like generating loads of multiple registers should ideally be done within
   // the scheduler pass by combining the loads during DAG postprocessing.
-  const ClusterInfo *CandCluster = Cand.AtTop ? TopCluster : BotCluster;
-  const ClusterInfo *TryCandCluster = TryCand.AtTop ? TopCluster : BotCluster;
-  if (tryGreater(TryCandCluster && TryCandCluster->contains(TryCand.SU),
-                 CandCluster && CandCluster->contains(Cand.SU), TryCand, Cand,
+  unsigned CandZoneCluster = Cand.AtTop ? TopClusterID : BotClusterID;
+  unsigned TryCandZoneCluster = TryCand.AtTop ? TopClusterID : BotClusterID;
+  bool CandIsClusterSucc =
+      isTheSameCluster(CandZoneCluster, Cand.SU->ParentClusterIdx);
+  bool TryCandIsClusterSucc =
+      isTheSameCluster(TryCandZoneCluster, TryCand.SU->ParentClusterIdx);
+
+  if (tryGreater(TryCandIsClusterSucc, CandIsClusterSucc, TryCand, Cand,
                  Cluster))
     return TryCand.Reason != NoCand;
 
@@ -189,10 +193,14 @@ bool PPCPostRASchedStrategy::tryCandidate(SchedCandidate &Cand,
     return TryCand.Reason != NoCand;
 
   // Keep clustered nodes together.
-  const ClusterInfo *CandCluster = Cand.AtTop ? TopCluster : BotCluster;
-  const ClusterInfo *TryCandCluster = TryCand.AtTop ? TopCluster : BotCluster;
-  if (tryGreater(TryCandCluster && TryCandCluster->contains(TryCand.SU),
-                 CandCluster && CandCluster->contains(Cand.SU), TryCand, Cand,
+  unsigned CandZoneCluster = Cand.AtTop ? TopClusterID : BotClusterID;
+  unsigned TryCandZoneCluster = TryCand.AtTop ? TopClusterID : BotClusterID;
+  bool CandIsClusterSucc =
+      isTheSameCluster(CandZoneCluster, Cand.SU->ParentClusterIdx);
+  bool TryCandIsClusterSucc =
+      isTheSameCluster(TryCandZoneCluster, TryCand.SU->ParentClusterIdx);
+
+  if (tryGreater(TryCandIsClusterSucc, CandIsClusterSucc, TryCand, Cand,
                  Cluster))
     return TryCand.Reason != NoCand;