diff --git a/lldb/source/Utility/Scalar.cpp b/lldb/source/Utility/Scalar.cpp
--- a/lldb/source/Utility/Scalar.cpp
+++ b/lldb/source/Utility/Scalar.cpp
@@ -331,7 +331,7 @@
 
 Scalar &Scalar::operator=(long long v) {
   m_type = e_slonglong;
-  m_integer = llvm::APInt(sizeof(long) * 8, v, true);
+  m_integer = llvm::APInt(sizeof(long long) * 8, v, true);
   return *this;
 }
 
diff --git a/lldb/unittests/Utility/ScalarTest.cpp b/lldb/unittests/Utility/ScalarTest.cpp
--- a/lldb/unittests/Utility/ScalarTest.cpp
+++ b/lldb/unittests/Utility/ScalarTest.cpp
@@ -188,6 +188,16 @@
             ScalarGetValue(std::numeric_limits<unsigned long long>::max()));
 }
 
+TEST(ScalarTest, LongLongAssigmentOperator) {
+  Scalar ull;
+  ull = std::numeric_limits<unsigned long long>::max();
+  EXPECT_EQ(std::numeric_limits<unsigned long long>::max(), ull.ULongLong());
+
+  Scalar sll;
+  sll = std::numeric_limits<signed long long>::max();
+  EXPECT_EQ(std::numeric_limits<signed long long>::max(), sll.SLongLong());
+}
+
 TEST(ScalarTest, Division) {
   Scalar lhs(5.0);
   Scalar rhs(2.0);