diff --git a/clang/lib/CIR/CodeGen/CIRGenRecordLayoutBuilder.cpp b/clang/lib/CIR/CodeGen/CIRGenRecordLayoutBuilder.cpp
index bf812c8a1793b..2baeb43c48b2e 100644
--- a/clang/lib/CIR/CodeGen/CIRGenRecordLayoutBuilder.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenRecordLayoutBuilder.cpp
@@ -824,7 +824,7 @@ void CIRRecordLowering::lowerUnion() {
     appendPaddingBytes(layoutSize - getSize(storageType));
 
   // Set packed if we need it.
-  if (layoutSize % getAlignment(storageType))
+  if (!layoutSize.isMultipleOf(getAlignment(storageType)))
     packed = true;
 }