switch the VRBaseMap in the scheduler from an std::map to a DenseMap.  This
speeds up the isel pass from 2.5570s to 2.4722s on kc++ (3.4%).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@33879 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/ScheduleDAGSimple.cpp b/lib/CodeGen/SelectionDAG/ScheduleDAGSimple.cpp
index 442b8ef..e4133ce 100644
--- a/lib/CodeGen/SelectionDAG/ScheduleDAGSimple.cpp
+++ b/lib/CodeGen/SelectionDAG/ScheduleDAGSimple.cpp
@@ -682,7 +682,7 @@
                           LI->first, RegMap->getRegClass(LI->second));
   }
   
-  std::map<SDNode*, unsigned> VRBaseMap;
+  DenseMap<SDNode*, unsigned> VRBaseMap;
   
   // For each node in the ordering
   for (unsigned i = 0, N = Ordering.size(); i < N; i++) {