Fix MSVC 2012 warning about a 32-bit shift that should be 64-bit

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173454 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/IR/Attributes.cpp b/lib/IR/Attributes.cpp
index 8ee7057..cbbf484 100644
--- a/lib/IR/Attributes.cpp
+++ b/lib/IR/Attributes.cpp
@@ -524,12 +524,12 @@
 
 uint64_t AttributeImpl::getAlignment() const {
   uint64_t Mask = Raw() & getAttrMask(Attribute::Alignment);
-  return 1U << ((Mask >> 16) - 1);
+  return 1ULL << ((Mask >> 16) - 1);
 }
 
 uint64_t AttributeImpl::getStackAlignment() const {
   uint64_t Mask = Raw() & getAttrMask(Attribute::StackAlignment);
-  return 1U << ((Mask >> 26) - 1);
+  return 1ULL << ((Mask >> 26) - 1);
 }
 
 void AttributeImpl::Profile(FoldingSetNodeID &ID, Constant *Data,