diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
--- a/clang/lib/Sema/SemaStmt.cpp
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -379,6 +379,12 @@
     return;
   }
 
+  if (ExprEvalContexts.back().Context ==
+      ExpressionEvaluationContext::ConstantEvaluated) {
+    Diag(Loc, DiagID) << R1 << R2;
+    return;
+  }
+
   DiagRuntimeBehavior(Loc, nullptr, PDiag(DiagID) << R1 << R2);
 }
 
diff --git a/clang/test/SemaCXX/warn-unused-value.cpp b/clang/test/SemaCXX/warn-unused-value.cpp
--- a/clang/test/SemaCXX/warn-unused-value.cpp
+++ b/clang/test/SemaCXX/warn-unused-value.cpp
@@ -138,3 +138,10 @@
   (void)arr3;
   (void)arr4;
 }
+
+#if __cplusplus >= 201103L // C++11 or later
+namespace test5 {
+int v[(5, 6)];                   // expected-warning {{expression result unused}}
+auto p1 = new double[4][(5, 6)]; // expected-warning {{expression result unused}}
+} // namespace test5
+#endif