rs6000: Correct the "length" attribute for trunctddd2

	* config/rs6000/dfp.md (trunctddd2): Correct the "length" attribute.

From-SVN: r237026

gcc/ChangeLog

+2016-06-02  Segher Boessenkool  <segher@kernel.crashing.org>
+
+	* config/rs6000/dfp.md (trunctddd2): Correct the "length" attribute.
+
 2016-06-01  David Malcolm  <dmalcolm@redhat.com>
 
 	* config/rl78/rl78.c (rl78_expand_prologue): Convert local

gcc/config/rs6000/dfp.md

@@ -173,7 +173,8 @@
    (clobber (match_scratch:TD 2 "=d"))]
   "TARGET_DFP"
   "drdpq %2,%1\;fmr %0,%2"
-  [(set_attr "type" "fp")])
+  [(set_attr "type" "fp")
+   (set_attr "length" "8")])
 
 (define_insn "adddd3"
   [(set (match_operand:DD 0 "gpc_reg_operand" "=d")