diff --git a/lib/mpi/longlong.h b/lib/mpi/longlong.h
index b90e255c2a68..93336502af08 100644
--- a/lib/mpi/longlong.h
+++ b/lib/mpi/longlong.h
@@ -216,7 +216,7 @@ extern UDItype __udiv_qrnnd(UDItype *, UDItype, UDItype, UDItype);
 	__asm__ ("%@ Inlined umul_ppmm\n" \
 		"umull %r1, %r0, %r2, %r3" \
 	: "=&r" ((USItype)(xh)), \
-			"=r" ((USItype)(xl)) \
+			"=&r" ((USItype)(xl)) \
 	: "r" ((USItype)(a)), \
 			"r" ((USItype)(b)) \
 	: "r0", "r1")