Fix two more memory leaks in threader

[Jeff Law]

These fix the remaining leaks in the threader that I'm aware of.  We 
failed to properly clean-up when we had to cancel certain jump threading 
opportunities.  So thankfully this wasn't a big leak.

Bootstrapped and regression tested on x86_64-unknown-linux-gnu. 
Installed on the trunk.

Jeff
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index fe4dfc4..27435c6 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2015-05-20  Jeff Law  <l...@redhat.com>
+
+       * tree-ssa-threadupdate.c (mark_threaded_blocks): Properly
+       dispose of the jump thread path when the jump threading
+       opportunity is cancelled.
+
 2015-05-20  Manuel López-Ibáñez  <m...@gcc.gnu.org>
 
        * diagnostic.c (diagnostic_print_caret_line): Fix off-by-one error
diff --git a/gcc/tree-ssa-threadupdate.c b/gcc/tree-ssa-threadupdate.c
index c5b78a4..4bccad0 100644
--- a/gcc/tree-ssa-threadupdate.c
+++ b/gcc/tree-ssa-threadupdate.c
@@ -2159,9 +2159,16 @@ mark_threaded_blocks (bitmap threaded_blocks)
         {
          /* Attach the path to the starting edge if none is yet recorded.  */
           if ((*path)[0]->e->aux == NULL)
-            (*path)[0]->e->aux = path;
-         else if (dump_file && (dump_flags & TDF_DETAILS))
-           dump_jump_thread_path (dump_file, *path, false);
+           {
+              (*path)[0]->e->aux = path;
+           }
+         else
+           {
+             paths.unordered_remove (i);
+             if (dump_file && (dump_flags & TDF_DETAILS))
+               dump_jump_thread_path (dump_file, *path, false);
+             delete_jump_thread_path (path);
+           }
         }
     }
   /* Second, look for paths that have any other jump thread attached to
@@ -2185,8 +2192,10 @@ mark_threaded_blocks (bitmap threaded_blocks)
          else
            {
              e->aux = NULL;
+             paths.unordered_remove (i);
              if (dump_file && (dump_flags & TDF_DETAILS))
                dump_jump_thread_path (dump_file, *path, false);
+             delete_jump_thread_path (path);
            }
        }
     }