diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -5247,6 +5247,9 @@
       for (Expr *A : Args.slice(ArgIx)) {
         ExprResult Arg = DefaultVariadicArgumentPromotion(A, CallType, FDecl);
         Invalid |= Arg.isInvalid();
+        // Copy blocks to the heap.
+        if (A->getType()->isBlockPointerType())
+          maybeExtendBlockObject(Arg);
         AllArgs.push_back(Arg.get());
       }
     }
diff --git a/clang/test/CodeGenObjC/arc-blocks.m b/clang/test/CodeGenObjC/arc-blocks.m
--- a/clang/test/CodeGenObjC/arc-blocks.m
+++ b/clang/test/CodeGenObjC/arc-blocks.m
@@ -730,5 +730,15 @@
   test20_callee(^{ (void)x; });
 }
 
+// CHECK-LABEL: define void @test21(
+// CHECK: %[[V6:.*]] = call i8* @llvm.objc.retainBlock(
+// CHECK: %[[V7:.*]] = bitcast i8* %[[V6]] to void ()*
+// CHECK: call void (i32, ...) @test21_callee(i32 1, void ()* %[[V7]]),
+
+void test21_callee(int n, ...);
+void test21(id x) {
+  test21_callee(1, ^{ (void)x; });
+}
+
 // CHECK: attributes [[NUW]] = { nounwind }
 // CHECK-UNOPT: attributes [[NUW]] = { nounwind }