Index: avr.md
===================================================================
--- gcc/config/avr/avr.md	(revision 132947)
+++ gcc/config/avr/avr.md	(working copy)
@@ -585,13 +585,13 @@
 	adc %B0,__zero_reg__"
   [(set_attr "length" "2")
    (set_attr "cc" "set_n")])
-
+;disable this as reload has problems with it.
 (define_insn "*addhi3_zero_extend2"
   [(set (match_operand:HI 0 "register_operand" "=r")
 	(plus:HI
 	 (zero_extend:HI (match_operand:QI 1 "register_operand" "%0"))
 	 (zero_extend:HI (match_operand:QI 2 "register_operand" "r"))))]
-  ""
+  "0"
   "add %0,%2
 	mov %B0,__zero_reg__
 	adc %B0,__zero_reg__"