[PATCH] Shrink tree_block

[Richard Guenther <rguenther@suse.de>]

This shrinks tree_block by noting that with mapped location the
block locus now pairs with the flags.  Also blocks do not need
a type and access to the chain member of tree_common is conveniently
wrapped with BLOCK_CHAIN.

So, bootstrapped and tested on x86_64-unknown-linux-gnu, I'll apply
this as a memory-savings regression fix later.

Richard.

2007-11-24  Richard Guenther  <rguenther@suse.de>

	* tree.h (BLOCK_CHAIN): Use tree_block.chain.
	(struct tree_block): Inherit from tree_base, add chain
	member.  Move locus member next to flags.

Index: tree.h
===================================================================
*** tree.h	(revision 130396)
--- tree.h	(working copy)
*************** struct varray_head_tag;
*** 2007,2013 ****
  #define BLOCK_SUPERCONTEXT(NODE) (BLOCK_CHECK (NODE)->block.supercontext)
  /* Note: when changing this, make sure to find the places
     that use chainon or nreverse.  */
! #define BLOCK_CHAIN(NODE) TREE_CHAIN (BLOCK_CHECK (NODE))
  #define BLOCK_ABSTRACT_ORIGIN(NODE) (BLOCK_CHECK (NODE)->block.abstract_origin)
  #define BLOCK_ABSTRACT(NODE) (BLOCK_CHECK (NODE)->block.abstract_flag)
  
--- 2008,2014 ----
  #define BLOCK_SUPERCONTEXT(NODE) (BLOCK_CHECK (NODE)->block.supercontext)
  /* Note: when changing this, make sure to find the places
     that use chainon or nreverse.  */
! #define BLOCK_CHAIN(NODE) (BLOCK_CHECK (NODE)->block.chain)
  #define BLOCK_ABSTRACT_ORIGIN(NODE) (BLOCK_CHECK (NODE)->block.abstract_origin)
  #define BLOCK_ABSTRACT(NODE) (BLOCK_CHECK (NODE)->block.abstract_flag)
  
*************** struct varray_head_tag;
*** 2054,2072 ****
  
  struct tree_block GTY(())
  {
!   struct tree_common common;
  
    unsigned handler_block_flag : 1;
    unsigned abstract_flag : 1;
    unsigned block_num : 30;
  
    tree vars;
    tree subblocks;
    tree supercontext;
    tree abstract_origin;
    tree fragment_origin;
    tree fragment_chain;
-   location_t locus;
  };
  \f
  /* Define fields and accessors for nodes representing data types.  */
--- 2055,2075 ----
  
  struct tree_block GTY(())
  {
!   struct tree_base base;
!   tree chain;
  
    unsigned handler_block_flag : 1;
    unsigned abstract_flag : 1;
    unsigned block_num : 30;
  
+   location_t locus;
+ 
    tree vars;
    tree subblocks;
    tree supercontext;
    tree abstract_origin;
    tree fragment_origin;
    tree fragment_chain;
  };
  \f
  /* Define fields and accessors for nodes representing data types.  */