Index: lib/CodeGen/CGCXX.cpp
===================================================================
--- lib/CodeGen/CGCXX.cpp
+++ lib/CodeGen/CGCXX.cpp
@@ -224,6 +224,11 @@
   } else {
     const auto *CD = cast<CXXConstructorDecl>(MD);
     GD = GlobalDecl(CD, toCXXCtorType(Type));
+
+    // As long as `this` argument always comes first
+    // we hardcode the position of the `src` argument
+    if (CD->isCopyOrMoveConstructor())
+      Fn->addParamAttr(1, llvm::Attribute::NoAlias);
   }
 
   setFunctionLinkage(GD, Fn);