Turn effective assert(0) into llvm_unreachable

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237379 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/TargetSchedule.cpp

@@ -242,13 +242,11 @@ unsigned TargetSchedModel::computeInstrLatency(unsigned Opcode) const {
 
   unsigned SCIdx = TII->get(Opcode).getSchedClass();
   const MCSchedClassDesc *SCDesc = SchedModel.getSchedClassDesc(SCIdx);
-  unsigned Latency = 0;
 
   if (SCDesc->isValid() && !SCDesc->isVariant())
     return computeInstrLatency(*SCDesc);
 
-  assert(Latency && "No MI sched latency");
-  return 0;
+  llvm_unreachable("No MI sched latency");
 }
 
 unsigned