Fix pdp11 building with the current trunk

[Jeff Law]

Additional checking of MD files has exposed a bug in the pdp11 backend. 
Namely it has a scratch operand with a lower number than other operands.

This patch adjusts the operand numbers.  I've verified this allows the 
pdp11 backend to build again.  Installed on the trunk.

Jeff

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index a4cd56f..124dca3 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2017-03-13  Jeff Law  <l...@redhat.com>
+
+       * config/pdp11/pdp11.md (movmemhi): Adjust operand numbers to
+       match_scratch operand is highest.
+
 2017-03-13  Martin Liska  <mli...@suse.cz>
 
        PR middle-end/78339
diff --git a/gcc/config/pdp11/pdp11.md b/gcc/config/pdp11/pdp11.md
index ee820f2..dde7711 100644
--- a/gcc/config/pdp11/pdp11.md
+++ b/gcc/config/pdp11/pdp11.md
@@ -373,9 +373,9 @@
                   (match_operand:BLK 1 "general_operand" "g,g"))
              (use (match_operand:HI 2 "general_operand" "n,mr"))
              (use (match_operand:HI 3 "immediate_operand" "i,i"))
-             (clobber (match_scratch:HI 4 "=&r,X"))
+             (clobber (match_scratch:HI 6 "=&r,X"))
+             (clobber (match_dup 4))
              (clobber (match_dup 5))
-             (clobber (match_dup 6))
              (clobber (match_dup 2))])]
   "(TARGET_BCOPY_BUILTIN)"
   "
@@ -387,8 +387,8 @@
     = replace_equiv_address (operands[1],
                             copy_to_mode_reg (Pmode, XEXP (operands[1], 0)));
 
-  operands[5] = XEXP (operands[0], 0);
-  operands[6] = XEXP (operands[1], 0);
+  operands[4] = XEXP (operands[0], 0);
+  operands[5] = XEXP (operands[1], 0);
 }")