Update DebugLoc while merging nodes at -O0.

Patch by Kyriakos Georgiou!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146670 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 477ec80..3c95059 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -266,7 +266,7 @@
                                    CodeGenOpt::Level OL) :
   MachineFunctionPass(ID), TM(tm), TLI(*tm.getTargetLowering()),
   FuncInfo(new FunctionLoweringInfo(TLI)),
-  CurDAG(new SelectionDAG(tm)),
+  CurDAG(new SelectionDAG(tm, OL)),
   SDB(new SelectionDAGBuilder(*CurDAG, *FuncInfo, OL)),
   GFI(),
   OptLevel(OL),