diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -4648,7 +4648,13 @@
                           InitDecl->getFlexibleArrayInitChars(getContext());
       CharUnits CstSize = CharUnits::fromQuantity(
           getDataLayout().getTypeAllocSize(Init->getType()));
-      assert(VarSize == CstSize && "Emitted constant has unexpected size");
+      // 'long double' is treated as 'double' in device code
+      const BuiltinType *BType = D->getType()->getAs<BuiltinType>();
+      bool IsLongDouble = BType && BType->getKind() == BuiltinType::LongDouble;
+      bool IsDevice = getLangOpts().HIP || getLangOpts().CUDA ||
+                      getLangOpts().OpenMPIsDevice;
+      assert((VarSize == CstSize || (IsDevice && IsLongDouble)) &&
+             "Emitted constant has unexpected size");
 #endif
     }
   }