diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -13533,7 +13533,9 @@
       return Info.Ctx.getTypeSize(DestType) == Info.Ctx.getTypeSize(SrcType);
     }
 
-    if (Info.Ctx.getLangOpts().CPlusPlus && DestType->isEnumeralType()) {
+    if (Info.Ctx.getLangOpts().CPlusPlus &&
+        Info.EvalMode == EvalInfo::EM_ConstantExpression &&
+        DestType->isEnumeralType()) {
       const EnumType *ET = dyn_cast<EnumType>(DestType.getCanonicalType());
       const EnumDecl *ED = ET->getDecl();
       // Check that the value is within the range of the enumeration values.
diff --git a/clang/test/SemaCXX/constant-expression-cxx11.cpp b/clang/test/SemaCXX/constant-expression-cxx11.cpp
--- a/clang/test/SemaCXX/constant-expression-cxx11.cpp
+++ b/clang/test/SemaCXX/constant-expression-cxx11.cpp
@@ -2421,6 +2421,7 @@
   constexpr E1 x1 = static_cast<E1>(-8);
   constexpr E1 x2 = static_cast<E1>(8);
   // expected-error@-1 {{integer value 8 is outside the valid range of values [-8, 7] for this enumeration type}}
+  E1 x2b = static_cast<E1>(8); // ok, not a constant expression context
 
   constexpr E2 x3 = static_cast<E2>(-8);
   // expected-error@-1 {{integer value -8 is outside the valid range of values [0, 7] for this enumeration type}}