Fix PR47612

[Bernd Schmidt]

This fixes a problem on cc0 machines where we split a sequence of insns
at a point where we shouldn't - between a cc0 setter and a cc0 user.

The fix is simple enough; just make sure not to pick a cc0 setter as the
end of such a sequence. The patch below was regression tested on
m68k-rtems4.11 by Joel Sherrill; I'll commit it as obvious in a few days
unless someone tells me it isn't.


Bernd

        * df-problems.c (can_move_insns_across): Don't pick a cc0 setter
        as the last insn of the sequence to be moved.

Index: df-problems.c
===================================================================
--- df-problems.c       (revision 172094)
+++ df-problems.c       (working copy)
@@ -4001,7 +4001,10 @@ can_move_insns_across (rtx from, rtx to,
          if (bitmap_intersect_p (merge_set, test_use)
              || bitmap_intersect_p (merge_use, test_set))
            break;
-         max_to = insn;
+#ifdef HAVE_cc0
+         if (!sets_cc0_p (insn))
+#endif
+           max_to = insn;
        }
       next = NEXT_INSN (insn);
       if (insn == to)
@@ -4038,7 +4041,11 @@ can_move_insns_across (rtx from, rtx to,
     {
       if (NONDEBUG_INSN_P (insn))
        {
-         if (!bitmap_intersect_p (test_set, local_merge_live))
+         if (!bitmap_intersect_p (test_set, local_merge_live)
+#ifdef HAVE_cc0
+             && !sets_cc0_p (insn)
+#endif
+             )
            {
              max_to = insn;
              break;