(relax_delay_slots): Delete jump around insn identical

to the insn in its delay slot.

From-SVN: r3606

diff --git a/gcc/reorg.c b/gcc/reorg.c
index efbc078e1198f1ccf265a887b53b62c93a3d743e..e78c44c4d3b7d6d2894db65010108536e5cfdb9a 100644 (file)
--- a/gcc/reorg.c
+++ b/gcc/reorg.c
@@ -3440,6 +3440,19 @@ relax_delay_slots (first)
          continue;
        }
 
+      /* See if this is an unconditional jump around a single insn which is
+        identical to the one in its delay slot.  In this case, we can just
+        delete the branch and the insn in its delay slot.  */
+      if (next && GET_CODE (next) == INSN
+         && prev_label (next_active_insn (next)) == target_label
+         && simplejump_p (insn)
+         && XVECLEN (pat, 0) == 2
+         && rtx_equal_p (PATTERN (next), PATTERN (XVECEXP (pat, 0, 1))))
+       {
+         delete_insn (insn);
+         continue;
+       }
+
       /* See if this jump (with its delay slots) branches around another
         jump (without delay slots).  If so, invert this jump and point
         it to the target of the second jump.  We cannot do this for