diff --git a/lib/Common/DataStructures/SparseBitVector.h b/lib/Common/DataStructures/SparseBitVector.h
index e7e148ee37e..4533cc1e997 100644
--- a/lib/Common/DataStructures/SparseBitVector.h
+++ b/lib/Common/DataStructures/SparseBitVector.h
@@ -80,7 +80,7 @@ struct BVSparseNode
 #endif
 };
 
-#if defined(_M_X64)
+#if defined(_M_ARM64) || defined(_M_X64)
 CompileAssert(sizeof(BVSparseNode) == 24); // Performance assert, BVSparseNode is heavily used in the backend, do perf measurement before changing this.
 #else
 CompileAssert(sizeof(BVSparseNode) == 16);