[AMDGPU] Add llvm_unreachable to switch statement added in d7100b398.

diff --git a/llvm/lib/Target/AMDGPU/GCNSchedStrategy.cpp b/llvm/lib/Target/AMDGPU/GCNSchedStrategy.cpp
index 1d83f2e..f8f1d02 100644 (file)
--- a/llvm/lib/Target/AMDGPU/GCNSchedStrategy.cpp
+++ b/llvm/lib/Target/AMDGPU/GCNSchedStrategy.cpp
@@ -460,6 +460,8 @@ GCNScheduleDAGMILive::createSchedStage(GCNSchedStageID SchedStageID) {
   case GCNSchedStageID::ILPInitialSchedule:
     return std::make_unique<ILPInitialScheduleStage>(SchedStageID, *this);
   }
+
+  llvm_unreachable("Unknown SchedStageID.");
 }
 
 void GCNScheduleDAGMILive::schedule() {