Collaboration diagram for _elim_graph:

Data Fields
int	size
vec< int >	nodes
vec< int >	edge_list
vec< source_location >	edge_locus
sbitmap	visited
vec< int >	stack
var_map	map
edge	e
vec< int >	const_dests
vec< tree >	const_copies
vec< source_location >	copy_locus

Detailed Description

@verbatim Convert a program in SSA form into Normal form.

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version.

GCC is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with GCC; see the file COPYING3. If not see http://www.gnu.org/licenses/.

FIXME: A lot of code here deals with expanding to RTL.  All that code
   should be in cfgexpand.c.

Used to hold all the components required to do SSA PHI elimination.
   The node and pred/succ list is a simple linear list of nodes and
   edges represented as pairs of nodes.

   The predecessor and successor list:  Nodes are entered in pairs, where
   [0] ->PRED, [1]->SUCC.  All the even indexes in the array represent
   predecessors, all the odd elements are successors.

   Rationale:
   When implemented as bitmaps, very large programs SSA->Normal times were
   being dominated by clearing the interference graph.

   Typically this list of edges is extremely small since it only includes
   PHI results and uses from a single edge which have not coalesced with
   each other.  This means that no virtual PHI nodes are included, and
   empirical evidence suggests that the number of edges rarely exceed
   3, and in a bootstrap of GCC, the maximum size encountered was 7.
   This also limits the number of possible nodes that are involved to
   rarely more than 6, and in the bootstrap of gcc, the maximum number
   of nodes encountered was 12.