[patch RFA middle-end] Fix PR target/41993

[Kaz Kojima]

Hi,

The attached patch is to solve PR target/41993 which will affect
targets using MODE_EXIT.
Without it, we can't find all return registers for __builtin_return
in mode-switching.c:create_pre_exit.  See the trail #4 by Uros in
the PR for the details.  The patch is tested with bootstrap and
regtested on i686-pc-linux-gnu with no new failures.  It's also
tested on cross sh4-unknown-linux-gnu.
OK for trunk?

Regards,
	kaz
--
2012-11-05  Uros Bizjak  <ubizjak@gmail.com>
	    Kaz Kojima  <kkojima@gcc.gnu.org>

	PR target/41993
	* mode-switching.c (create_pre_exit): Set return_copy to
	last_insn when copy_start is a pseudo reg.

--- ORIG/trunk/gcc/mode-switching.c	2012-11-05 08:07:55.000000000 +0900
+++ trunk/gcc/mode-switching.c	2012-11-05 19:22:56.000000000 +0900
@@ -324,7 +324,10 @@ create_pre_exit (int n_entities, int *en
 		    else
 		      break;
 		    if (copy_start >= FIRST_PSEUDO_REGISTER)
-		      break;
+		      {
+			last_insn = return_copy;
+			continue;
+		      }
 		    copy_num
 		      = hard_regno_nregs[copy_start][GET_MODE (copy_reg)];