Collaboration diagram for st_expr:

Data Fields
rtx	pattern
rtx	pattern_regs
rtx	antic_stores
rtx	avail_stores
struct st_expr *	next
int	index
unsigned int	hash_index
rtx	reaching_reg

Detailed Description

@verbatim Store motion via Lazy Code Motion on the reverse CFG.

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/.

This pass implements downward store motion.
   As of May 1, 2009, the pass is not enabled by default on any target,
   but bootstrap completes on ia64 and x86_64 with the pass enabled.

TODO:
   - remove_reachable_equiv_notes is an incomprehensible pile of goo and
     a compile time hog that needs a rewrite (maybe cache st_exprs to
     invalidate REG_EQUAL/REG_EQUIV notes for?).
   - pattern_regs in st_expr should be a regset (on its own obstack).
   - antic_stores and avail_stores should be VECs instead of lists.
   - store_motion_mems should be a vec instead of a list.
   - there should be an alloc pool for struct st_expr objects.
   - investigate whether it is helpful to make the address of an st_expr
     a cselib VALUE.
   - when GIMPLE alias information is exported, the effectiveness of this
     pass should be re-evaluated.

This is a list of store expressions (MEMs).  The structure is used
   as an expression table to track stores which look interesting, and
   might be moveable towards the exit block.