diff --git a/src/longlong.h b/src/longlong.h
index e880587..023f47e 100644
--- a/src/longlong.h
+++ b/src/longlong.h
@@ -530,23 +530,16 @@ extern UWtype __MPN(udiv_qrnnd) (UWtype *, UWtype, UWtype, UWtype);
 #endif /* __arm__ */
 
 #if defined (__aarch64__) && W_TYPE_SIZE == 64
+/* FIXME: Extend the immediate range for the low word by using both
+   ADDS and SUBS, since they set carry in the same way.  */
 #define add_ssaaaa(sh, sl, ah, al, bh, bl) \
-  __asm__ ("adds\t%1, %4, %5\n\tadc\t%0, %2, %3"			\
+  __asm__ ("adds\t%1, %x4, %5\n\tadc\t%0, %x2, %x3"                     \
 	   : "=r" (sh), "=&r" (sl)					\
-	   : "r" (ah), "rZ" (bh), "%r" (al), "rI" (bl) __CLOBBER_CC)
+           : "rZ" (ah), "rZ" (bh), "%r" (al), "rI" (bl) __CLOBBER_CC)
 #define sub_ddmmss(sh, sl, ah, al, bh, bl) \
-  do {									\
-    if (__builtin_constant_p (bl))					\
-      {									\
-	__asm__ ("subs\t%1, %4, %5\n\tsbc\t%0, %2, %3"			\
-		 : "=r" (sh), "=&r" (sl)				\
-		 : "r" (ah), "r" (bh), "r" (al), "rI" (bl) __CLOBBER_CC); \
-      }									\
-    else /* only bh might be a constant */				\
-      __asm__ ("subs\t%1, %4, %5\n\tsbc\t%0, %2, %3"			\
-	       : "=r" (sh), "=&r" (sl)					\
-	       : "r" (ah), "rZ" (bh), "r" (al), "rI" (bl) __CLOBBER_CC);\
-    } while (0)
+  __asm__ ("subs\t%1, %x4, %5\n\tsbc\t%0, %x2, %x3"                     \
+           : "=r,r" (sh), "=&r,&r" (sl)                                 \
+           : "rZ,rZ" (ah), "rZ,rZ" (bh), "r,Z" (al), "rI,r" (bl) __CLOBBER_CC)
 #define umul_ppmm(ph, pl, m0, m1) \
   do {									\
     UDItype __m0 = (m0), __m1 = (m1);					\