#include <gimple-range-gori.h>

Inheritance diagram for range_def_chain:

Collaboration diagram for range_def_chain:

[legend]

Data Structures
struct	rdc

Public Member Functions
	range_def_chain ()
	~range_def_chain ()
tree	depend1 (tree name) const
tree	depend2 (tree name) const
bool	in_chain_p (tree name, tree def)
bool	chain_import_p (tree name, tree import)
void	register_dependency (tree name, tree ssa1, basic_block bb=NULL)
void	dump (FILE f, basic_block bb, const char prefix=NULL)

Protected Member Functions
bool	has_def_chain (tree name)
bool	def_chain_in_bitmap_p (tree name, bitmap b)
void	add_def_chain_to_bitmap (bitmap b, tree name)
bitmap	get_def_chain (tree name)
bitmap	get_imports (tree name)

Protected Attributes
bitmap_obstack	m_bitmaps

Private Member Functions
void	set_import (struct rdc &data, tree imp, bitmap b)

Private Attributes
vec< rdc >	m_def_chain
int	m_logical_depth

Detailed Description

Header file for gimple range GORI structures.
   Copyright (C) 2017-2025 Free Software Foundation, Inc.
   Contributed by Andrew MacLeod <amacleod@redhat.com>
   and Aldy Hernandez <aldyh@redhat.com>.

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/>.

Constructor & Destructor Documentation

◆ range_def_chain()

range_def_chain::range_def_chain ( )

RANGE_DEF_CHAIN is used to determine which SSA names in a block can
have range information calculated for them, and what the
dependencies on each other are.

Information for a basic block is calculated once and stored.  It is
only calculated the first time a query is made, so if no queries
are made, there is little overhead.

The def_chain bitmap is indexed by SSA_NAME_VERSION.  Bits are set
within this bitmap to indicate SSA names that are defined in the
SAME block and used to calculate this SSA name.


 <bb 2> :
   _1 = x_4(D) + -2;
   _2 = _1 * 4;
   j_7 = foo ();
   q_5 = _2 + 3;
   if (q_5 <= 13)

 _1  : x_4(D)
 _2  : 1  x_4(D)
 q_5  : _1  _2  x_4(D)

 This dump indicates the bits set in the def_chain vector.
 as well as demonstrates the def_chain bits for the related ssa_names.

 Checking the chain for _2 indicates that _1 and x_4 are used in
 its evaluation.

 Def chains also only include statements which are valid gimple
 so a def chain will only span statements for which the range
 engine implements operations for.

References bitmap_obstack_initialize(), m_bitmaps, m_def_chain, m_logical_depth, and num_ssa_names.