[PATCH] Fix loop preserving in loop header copying

[Richard Biener]

There's a simple mistake in gimple_duplicate_sese_region that
causes all loop-header copied loops to be thrown away (but soon
re-discovered, hopefully without somebody inbetween messing things up).

Fixed like the following, bootstrapped on x86_64-unknown-linux-gnu,
testing in progress.

Richard.

2014-02-05  Richard Biener  <rguent...@suse.de>

        * tree-cfg.c (gimple_duplicate_sese_region): Fix ordering of
        set_loop_copy and initialize_original_copy_tables.

Index: gcc/tree-cfg.c
===================================================================
*** gcc/tree-cfg.c      (revision 207497)
--- gcc/tree-cfg.c      (working copy)
*************** gimple_duplicate_sese_region (edge entry
*** 5879,5892 ****
        return false;
      }
  
-   set_loop_copy (loop, loop);
- 
    /* In case the function is used for loop header copying (which is the 
primary
       use), ensure that EXIT and its copy will be new latch and entry edges.  
*/
    if (loop->header == entry->dest)
      {
        copying_header = true;
-       set_loop_copy (loop, loop_outer (loop));
  
        if (!dominated_by_p (CDI_DOMINATORS, loop->latch, exit->src))
        return false;
--- 5905,5915 ----
*************** gimple_duplicate_sese_region (edge entry
*** 5897,5910 ****
          return false;
      }
  
    if (!region_copy)
      {
        region_copy = XNEWVEC (basic_block, n_region);
        free_region_copy = true;
      }
  
-   initialize_original_copy_tables ();
- 
    /* Record blocks outside the region that are dominated by something
       inside.  */
    if (update_dominance)
--- 5920,5938 ----
          return false;
      }
  
+   initialize_original_copy_tables ();
+ 
+   if (copying_header)
+     set_loop_copy (loop, loop_outer (loop));
+   else
+     set_loop_copy (loop, loop);
+ 
    if (!region_copy)
      {
        region_copy = XNEWVEC (basic_block, n_region);
        free_region_copy = true;
      }
  
    /* Record blocks outside the region that are dominated by something
       inside.  */
    if (update_dominance)