[tree-ssa] Small cleanup for dominator optimizers

[Steven Bosscher <s dot bosscher at student dot tudelft dot nl>]

If we're going to iterate a few times in the dominator optimizers, then
creating/deleting the hash table should be done outside the loop.  OK?

Gr.
Steven


2003-07-23  Steven Bosscher  <steven@gcc.gnu.org>

	* tree-ssa-dom.c (tree_ssa_dominator_optimize): Make
	found_unreachable a bool.  Create/delete hash tables for
	copies and available exprs outside the main loop.  Use
	htab_clean to whipe them after each iteration.

Index: tree-ssa-dom.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/Attic/tree-ssa-dom.c,v
retrieving revision 1.1.2.8
diff -c -3 -p -r1.1.2.8 tree-ssa-dom.c
*** tree-ssa-dom.c	22 Jul 2003 02:50:15 -0000	1.1.2.8
--- tree-ssa-dom.c	23 Jul 2003 08:55:58 -0000
*************** static void htab_statistics (FILE *, hta
*** 107,113 ****
  bool
  tree_ssa_dominator_optimize (tree fndecl)
  {
!   int found_unreachable;
    bitmap unreachable_bitmap = BITMAP_XMALLOC ();
  
    timevar_push (TV_TREE_SSA_DOMINATOR_OPTS);
--- 107,113 ----
  bool
  tree_ssa_dominator_optimize (tree fndecl)
  {
!   bool found_unreachable;
    bitmap unreachable_bitmap = BITMAP_XMALLOC ();
  
    timevar_push (TV_TREE_SSA_DOMINATOR_OPTS);
*************** tree_ssa_dominator_optimize (tree fndecl
*** 115,120 ****
--- 115,124 ----
    /* Set up debugging dump files.  */
    dump_file = dump_begin (TDI_dom, &dump_flags);
  
+   /* Create our hash tables.  */
+   const_and_copies = htab_create (1024, var_value_hash, var_value_eq, free);
+   avail_exprs = htab_create (1024, avail_expr_hash, avail_expr_eq, NULL);
+ 
    /* Indicate that we have not propagated any ADDR_EXPRs.  */
    addr_expr_propagated_p = false;
  
*************** tree_ssa_dominator_optimize (tree fndecl
*** 127,142 ****
      {
        int i;
  
!       /* Create our hash tables.  */
!       const_and_copies = htab_create (1024, var_value_hash, var_value_eq, free);
!       avail_exprs = htab_create (1024, avail_expr_hash, avail_expr_eq, NULL);
! 
!       /* Now optimize the dominator tree.  */
        optimize_block (ENTRY_BLOCK_PTR, NULL, 0);
  
        /* Wipe the hash tables.  */
!       htab_delete (const_and_copies);
!       htab_delete (avail_exprs);
  
        /* We may have made some basic blocks unreachable.  We do not
  	 want to call tree_cleanup_cfg here as it renumbers the blocks
--- 131,142 ----
      {
        int i;
  
!       /* Optimize the dominator tree.  */
        optimize_block (ENTRY_BLOCK_PTR, NULL, 0);
  
        /* Wipe the hash tables.  */
!       htab_empty (const_and_copies);
!       htab_empty (avail_exprs);
  
        /* We may have made some basic blocks unreachable.  We do not
  	 want to call tree_cleanup_cfg here as it renumbers the blocks
*************** tree_ssa_dominator_optimize (tree fndecl
*** 147,153 ****
  	 complete removal of the unreachable blocks.  */
        find_unreachable_blocks ();
  
!       found_unreachable = 0;
  
        for (i = 0; i < n_basic_blocks; i++)
  	{
--- 147,153 ----
  	 complete removal of the unreachable blocks.  */
        find_unreachable_blocks ();
  
!       found_unreachable = false;
  
        for (i = 0; i < n_basic_blocks; i++)
  	{
*************** tree_ssa_dominator_optimize (tree fndecl
*** 160,166 ****
  	      if (bitmap_bit_p (unreachable_bitmap, bb->index))
  		continue;
  
! 	      found_unreachable = 1;
  	      bitmap_set_bit (unreachable_bitmap, bb->index);
  	      remove_phi_nodes_and_edges_for_unreachable_block (bb);
  	    }
--- 160,166 ----
  	      if (bitmap_bit_p (unreachable_bitmap, bb->index))
  		continue;
  
! 	      found_unreachable = true;
  	      bitmap_set_bit (unreachable_bitmap, bb->index);
  	      remove_phi_nodes_and_edges_for_unreachable_block (bb);
  	    }
*************** tree_ssa_dominator_optimize (tree fndecl
*** 168,173 ****
--- 168,175 ----
      }
    while (found_unreachable);
  
+   htab_delete (const_and_copies);
+   htab_delete (avail_exprs);
    BITMAP_XFREE (unreachable_bitmap);
  
    /* Debugging dumps.  */