mi-sched: Load clustering is a bit to expensive to enable unconditionally.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189990 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/MachineScheduler.cpp b/lib/CodeGen/MachineScheduler.cpp
index 0aacc3a..d9da838 100644
--- a/lib/CodeGen/MachineScheduler.cpp
+++ b/lib/CodeGen/MachineScheduler.cpp
@@ -2753,7 +2753,7 @@
   // data and pass it to later mutations. Have a single mutation that gathers
   // the interesting nodes in one pass.
   DAG->addMutation(new CopyConstrain(DAG->TII, DAG->TRI));
-  if (EnableLoadCluster)
+  if (EnableLoadCluster && DAG->TII->enableClusterLoads())
     DAG->addMutation(new LoadClusterMutation(DAG->TII, DAG->TRI));
   if (EnableMacroFusion)
     DAG->addMutation(new MacroFusion(DAG->TII));