GCC Middle and Back End API Reference
ddg.h
Go to the documentation of this file.
1/* DDG - Data Dependence Graph - interface.
2 Copyright (C) 2004-2024 Free Software Foundation, Inc.
3 Contributed by Ayal Zaks and Mustafa Hagog <zaks,mustafa@il.ibm.com>
4
5This file is part of GCC.
6
7GCC is free software; you can redistribute it and/or modify it under
8the terms of the GNU General Public License as published by the Free
9Software Foundation; either version 3, or (at your option) any later
10version.
11
12GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13WARRANTY; without even the implied warranty of MERCHANTABILITY or
14FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15for more details.
16
17You should have received a copy of the GNU General Public License
18along with GCC; see the file COPYING3. If not see
19<http://www.gnu.org/licenses/>. */
20
21#ifndef GCC_DDG_H
22#define GCC_DDG_H
23
24/* For sbitmap. */
25
26typedef struct ddg_node *ddg_node_ptr;
27typedef struct ddg_edge *ddg_edge_ptr;
28typedef struct ddg *ddg_ptr;
29typedef struct ddg_scc *ddg_scc_ptr;
31
34
35/* The following two macros enables direct access to the successors and
36 predecessors bitmaps held in each ddg_node. Do not make changes to
37 these bitmaps, unless you want to change the DDG. */
38#define NODE_SUCCESSORS(x) ((x)->successors)
39#define NODE_PREDECESSORS(x) ((x)->predecessors)
40
41/* A structure that represents a node in the DDG. */
43{
44 /* Each node has a unique CUID index. These indices increase monotonically
45 (according to the order of the corresponding INSN in the BB), starting
46 from 0 with no gaps. */
47 int cuid;
48
49 /* The insn represented by the node. */
51
52 /* A note preceding INSN (or INSN itself), such that all insns linked
53 from FIRST_NOTE until INSN (inclusive of both) are moved together
54 when reordering the insns. This takes care of notes that should
55 continue to precede INSN. */
57
58 /* Incoming and outgoing dependency edges. */
61
62 /* Each bit corresponds to a ddg_node according to its cuid, and is
63 set iff the node is a successor/predecessor of "this" node. */
66
67 /* Temporary array used for Floyd-Warshall algorithm to find
68 scc recurrence length. */
70
71 /* For general use by algorithms manipulating the ddg. */
72 union {
73 int count;
74 void *info;
75 } aux;
76};
77
78/* A structure that represents an edge in the DDG. */
80{
81 /* The source and destination nodes of the dependency edge. */
84
85 /* TRUE, OUTPUT or ANTI dependency. */
87
88 /* REG or MEM dependency. */
90
91 /* Latency of the dependency. */
93
94 /* The distance: number of loop iterations the dependency crosses. */
96
97 /* The following two fields are used to form a linked list of the in/out
98 going edges to/from each node. */
101
102 /* Is true when edge is already in scc. */
103 bool in_scc;
104};
105
106/* This structure holds the Data Dependence Graph for a basic block. */
107struct ddg
108{
109 /* The basic block for which this DDG is built. */
111
112 /* Number of instructions in the basic block. */
114
115 /* Number of load/store instructions in the BB - statistics. */
118
119 /* This array holds the nodes in the graph; it is indexed by the node
120 cuid, which follows the order of the instructions in the BB. */
122
123 /* The branch closing the loop. */
125
126 /* Build dependence edges for closing_branch, when set. In certain cases,
127 the closing branch can be dealt with separately from the insns of the
128 loop, and then no such deps are needed. */
130
131 /* Array and number of backarcs (edges with distance > 0) in the DDG. */
134};
135
136
137/* Holds information on an SCC (Strongly Connected Component) of the DDG. */
139{
140 /* A bitmap that represents the nodes of the DDG that are in the SCC. */
142
143 /* Array and number of backarcs (edges with distance > 0) in the SCC. */
146
147 /* The maximum of (total_latency/total_distance) over all cycles in SCC. */
149};
150
151/* This structure holds the SCCs of the DDG. */
153{
154 /* Array that holds the SCCs in the DDG, and their number. */
157
159};
160
161
162ddg_ptr create_ddg (basic_block, int closing_branch_deps);
164
165void print_ddg (FILE *, ddg_ptr);
166void vcg_print_ddg (FILE *, ddg_ptr);
169
171
174
177
179
181
182#endif /* GCC_DDG_H */
int find_nodes_on_paths(sbitmap result, ddg_ptr, sbitmap from, sbitmap to)
void find_successors(sbitmap result, ddg_ptr, sbitmap)
struct ddg_scc * ddg_scc_ptr
Definition ddg.h:29
void free_ddg_all_sccs(ddg_all_sccs_ptr)
dep_data_type
Definition ddg.h:33
@ REG_DEP
Definition ddg.h:33
@ REG_OR_MEM_DEP
Definition ddg.h:33
@ MEM_DEP
Definition ddg.h:33
@ REG_AND_MEM_DEP
Definition ddg.h:33
ddg_all_sccs_ptr create_ddg_all_sccs(ddg_ptr)
struct ddg * ddg_ptr
Definition ddg.h:28
void free_ddg(ddg_ptr)
void print_ddg(FILE *, ddg_ptr)
struct ddg_edge * ddg_edge_ptr
Definition ddg.h:27
struct ddg_node * ddg_node_ptr
Definition ddg.h:26
ddg_node_ptr get_node_of_insn(ddg_ptr, rtx_insn *)
void print_ddg_edge(FILE *, ddg_edge_ptr)
struct ddg_all_sccs * ddg_all_sccs_ptr
Definition ddg.h:30
void vcg_print_ddg(FILE *, ddg_ptr)
dep_type
Definition ddg.h:32
@ TRUE_DEP
Definition ddg.h:32
@ OUTPUT_DEP
Definition ddg.h:32
@ ANTI_DEP
Definition ddg.h:32
void find_predecessors(sbitmap result, ddg_ptr, sbitmap)
void print_sccs(FILE *, ddg_all_sccs_ptr, ddg_ptr)
ddg_ptr create_ddg(basic_block, int closing_branch_deps)
bool autoinc_var_is_used_p(rtx_insn *, rtx_insn *)
Definition basic-block.h:117
Definition ddg.h:153
ddg_scc_ptr * sccs
Definition ddg.h:155
int num_sccs
Definition ddg.h:156
ddg_ptr ddg
Definition ddg.h:158
Definition ddg.h:80
int latency
Definition ddg.h:92
ddg_edge_ptr next_in
Definition ddg.h:99
bool in_scc
Definition ddg.h:103
ddg_node_ptr src
Definition ddg.h:82
int distance
Definition ddg.h:95
ddg_edge_ptr next_out
Definition ddg.h:100
dep_data_type data_type
Definition ddg.h:89
dep_type type
Definition ddg.h:86
ddg_node_ptr dest
Definition ddg.h:83
Definition ddg.h:43
union ddg_node::@14 aux
rtx_insn * insn
Definition ddg.h:50
ddg_edge_ptr in
Definition ddg.h:59
rtx_insn * first_note
Definition ddg.h:56
int * max_dist
Definition ddg.h:69
int cuid
Definition ddg.h:47
sbitmap predecessors
Definition ddg.h:65
sbitmap successors
Definition ddg.h:64
void * info
Definition ddg.h:74
ddg_edge_ptr out
Definition ddg.h:60
int count
Definition ddg.h:73
Definition ddg.h:139
sbitmap nodes
Definition ddg.h:141
int recurrence_length
Definition ddg.h:148
int num_backarcs
Definition ddg.h:145
ddg_edge_ptr * backarcs
Definition ddg.h:144
Definition ddg.h:108
int num_backarcs
Definition ddg.h:132
ddg_node_ptr nodes
Definition ddg.h:121
basic_block bb
Definition ddg.h:110
ddg_edge_ptr * backarcs
Definition ddg.h:133
int closing_branch_deps
Definition ddg.h:129
int num_loads
Definition ddg.h:116
int num_stores
Definition ddg.h:117
ddg_node_ptr closing_branch
Definition ddg.h:124
int num_nodes
Definition ddg.h:113
Definition rtl.h:545
Definition sbitmap.h:87