[llvm] [MachineScheduler] Make cluster check more efficient (PR #150884)

[Matt Arsenault via llvm-commits]

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@@ -4263,8 +4268,9 @@ void GenericScheduler::schedNode(SUnit *SU, bool IsTopNode) {
       reschedulePhysReg(SU, true);
   } else {
     SU->BotReadyCycle = std::max(SU->BotReadyCycle, Bot.getCurrCycle());
-    BotCluster = DAG->getCluster(SU->ParentClusterIdx);
-    LLVM_DEBUG(if (BotCluster) {
+    BotClusterID = SU->ParentClusterIdx;
+    LLVM_DEBUG(if (BotClusterID != InvalidClusterId) {
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arsenm wrote:

This would format better if you added a wrapping {} like `LLVM_DEBUG({})`

https://github.com/llvm/llvm-project/pull/150884