Fix integer undefined behavior due to signed left shift overflow in LLVM.
Reviewed offline by chandlerc.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162623 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index f4fe892..3ab0b46 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -1097,10 +1097,9 @@
          "Cannot set target flags on target-independent globals");
 
   // Truncate (with sign-extension) the offset value to the pointer size.
-  EVT PTy = TLI.getPointerTy();
-  unsigned BitWidth = PTy.getSizeInBits();
+  unsigned BitWidth = TLI.getPointerTy().getSizeInBits();
   if (BitWidth < 64)
-    Offset = (Offset << (64 - BitWidth) >> (64 - BitWidth));
+    Offset = SignExtend64(Offset, BitWidth);
 
   const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV);
   if (!GVar) {