re PR target/52667 (sh_reorg segfault)

2012-03-27  Chung-Lin Tang  <cltang@codesourcery.com>

	PR target/52667
	* config/sh/sh.c (find_barrier): Add equality check of last_got
	to avoid going above orig insn. Update comments.

From-SVN: r185867

gcc/ChangeLog

+2012-03-27  Chung-Lin Tang  <cltang@codesourcery.com>
+
+	PR target/52667
+	* config/sh/sh.c (find_barrier): Add equality check of last_got
+	to avoid going above orig insn. Update comments.
+
 2012-03-27  Richard Guenther  <rguenther@suse.de>
 
 	PR middle-end/52720

gcc/config/sh/sh.c

@@ -4751,8 +4751,12 @@ find_barrier (int num_mova, rtx mova, rtx from)
       /* Don't emit a constant table int the middle of global pointer setting,
 	 since that that would move the addressing base GOT into another table. 
 	 We need the first mov instruction before the _GLOBAL_OFFSET_TABLE_
-	 in the pool anyway, so just move up the whole constant pool.  */
-      if (last_got)
+	 in the pool anyway, so just move up the whole constant pool.
+
+	 However, avoid doing so when the last single GOT mov is the starting
+	 insn itself. Going past above the start insn would create a negative
+	 offset, causing errors.  */
+      if (last_got && last_got != orig)
         from = PREV_INSN (last_got);
 
       /* Don't insert the constant pool table at the position which