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90e88fd3 | 1 | /* Gimple range edge functionaluity. |
99dee823 | 2 | Copyright (C) 2020-2021 Free Software Foundation, Inc. |
90e88fd3 AM |
3 | Contributed by Andrew MacLeod <amacleod@redhat.com> |
4 | and Aldy Hernandez <aldyh@redhat.com>. | |
5 | ||
6 | This file is part of GCC. | |
7 | ||
8 | GCC is free software; you can redistribute it and/or modify | |
9 | it under the terms of the GNU General Public License as published by | |
10 | the Free Software Foundation; either version 3, or (at your option) | |
11 | any later version. | |
12 | ||
13 | GCC is distributed in the hope that it will be useful, | |
14 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | GNU General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
19 | along with GCC; see the file COPYING3. If not see | |
20 | <http://www.gnu.org/licenses/>. */ | |
21 | ||
22 | ||
23 | #include "config.h" | |
24 | #include "system.h" | |
25 | #include "coretypes.h" | |
26 | #include "backend.h" | |
27 | #include "tree.h" | |
28 | #include "gimple.h" | |
29 | #include "ssa.h" | |
30 | #include "gimple-pretty-print.h" | |
31 | #include "gimple-iterator.h" | |
32 | #include "tree-cfg.h" | |
33 | #include "gimple-range.h" | |
34 | ||
35 | // If there is a range control statment at the end of block BB, return it. | |
36 | // Otherwise return NULL. | |
37 | ||
38 | gimple * | |
39 | gimple_outgoing_range_stmt_p (basic_block bb) | |
40 | { | |
41 | gimple_stmt_iterator gsi = gsi_last_nondebug_bb (bb); | |
42 | if (!gsi_end_p (gsi)) | |
43 | { | |
44 | gimple *s = gsi_stmt (gsi); | |
45 | if (is_a<gcond *> (s) && gimple_range_handler (s)) | |
46 | return gsi_stmt (gsi); | |
47 | gswitch *sw = dyn_cast<gswitch *> (s); | |
48 | if (sw && irange::supports_type_p (TREE_TYPE (gimple_switch_index (sw)))) | |
49 | return gsi_stmt (gsi); | |
50 | } | |
51 | return NULL; | |
52 | } | |
53 | ||
54 | ||
55 | outgoing_range::outgoing_range () | |
56 | { | |
57 | m_edge_table = NULL; | |
58 | } | |
59 | ||
60 | outgoing_range::~outgoing_range () | |
61 | { | |
62 | if (m_edge_table) | |
63 | delete m_edge_table; | |
64 | } | |
65 | ||
66 | ||
67 | // Get a range for a switch edge E from statement S and return it in R. | |
68 | // Use a cached value if it exists, or calculate it if not. | |
69 | ||
70 | bool | |
71 | outgoing_range::get_edge_range (irange &r, gimple *s, edge e) | |
72 | { | |
73 | gcc_checking_assert (is_a<gswitch *> (s)); | |
74 | gswitch *sw = as_a<gswitch *> (s); | |
75 | ||
76 | // ADA currently has cases where the index is 64 bits and the case | |
77 | // arguments are 32 bit, causing a trap when we create a case_range. | |
78 | // Until this is resolved (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87798) | |
79 | // punt on switches where the labels dont match the argument. | |
80 | if (gimple_switch_num_labels (sw) > 1 && | |
81 | TYPE_PRECISION (TREE_TYPE (CASE_LOW (gimple_switch_label (sw, 1)))) != | |
82 | TYPE_PRECISION (TREE_TYPE (gimple_switch_index (sw)))) | |
83 | return false; | |
84 | ||
85 | if (!m_edge_table) | |
86 | m_edge_table = new hash_map<edge, irange *> (n_edges_for_fn (cfun)); | |
87 | ||
88 | irange **val = m_edge_table->get (e); | |
89 | if (!val) | |
90 | { | |
91 | calc_switch_ranges (sw); | |
92 | val = m_edge_table->get (e); | |
93 | gcc_checking_assert (val); | |
94 | } | |
95 | r = **val; | |
96 | return true; | |
97 | } | |
98 | ||
99 | ||
100 | // Calculate all switch edges from SW and cache them in the hash table. | |
101 | ||
102 | void | |
103 | outgoing_range::calc_switch_ranges (gswitch *sw) | |
104 | { | |
105 | bool existed; | |
106 | unsigned x, lim; | |
107 | lim = gimple_switch_num_labels (sw); | |
108 | tree type = TREE_TYPE (gimple_switch_index (sw)); | |
90e88fd3 | 109 | edge default_edge = gimple_switch_default_edge (cfun, sw); |
90e88fd3 | 110 | |
739526a1 AH |
111 | // This should be the first call into this switch. |
112 | // | |
113 | // Allocate an int_range_max for the default range case, start with | |
114 | // varying and intersect each other case from it. | |
115 | irange *default_range = m_range_allocator.allocate (255); | |
116 | default_range->set_varying (type); | |
90e88fd3 AM |
117 | |
118 | for (x = 1; x < lim; x++) | |
119 | { | |
120 | edge e = gimple_switch_edge (cfun, sw, x); | |
121 | ||
122 | // If this edge is the same as the default edge, do nothing else. | |
123 | if (e == default_edge) | |
124 | continue; | |
125 | ||
126 | tree low = CASE_LOW (gimple_switch_label (sw, x)); | |
127 | tree high = CASE_HIGH (gimple_switch_label (sw, x)); | |
128 | if (!high) | |
129 | high = low; | |
130 | ||
131 | // Remove the case range from the default case. | |
132 | int_range_max def_range (low, high); | |
133 | range_cast (def_range, type); | |
134 | def_range.invert (); | |
739526a1 | 135 | default_range->intersect (def_range); |
90e88fd3 AM |
136 | |
137 | // Create/union this case with anything on else on the edge. | |
138 | int_range_max case_range (low, high); | |
139 | range_cast (case_range, type); | |
140 | irange *&slot = m_edge_table->get_or_insert (e, &existed); | |
141 | if (existed) | |
142 | { | |
143 | case_range.union_ (*slot); | |
144 | if (slot->fits_p (case_range)) | |
145 | { | |
146 | *slot = case_range; | |
147 | continue; | |
148 | } | |
149 | } | |
150 | // If there was an existing range and it doesn't fit, we lose the memory. | |
151 | // It'll get reclaimed when the obstack is freed. This seems less | |
152 | // intrusive than allocating max ranges for each case. | |
153 | slot = m_range_allocator.allocate (case_range); | |
154 | } | |
739526a1 AH |
155 | |
156 | irange *&slot = m_edge_table->get_or_insert (default_edge, &existed); | |
157 | // This should be the first call into this switch. | |
158 | gcc_checking_assert (!existed); | |
159 | slot = default_range; | |
90e88fd3 AM |
160 | } |
161 | ||
162 | ||
163 | // Calculate the range forced on on edge E by control flow, return it | |
164 | // in R. Return the statment which defines the range, otherwise | |
165 | // return NULL | |
166 | ||
167 | gimple * | |
168 | outgoing_range::edge_range_p (irange &r, edge e) | |
169 | { | |
170 | // Determine if there is an outgoing edge. | |
171 | gimple *s = gimple_outgoing_range_stmt_p (e->src); | |
172 | if (!s) | |
173 | return NULL; | |
174 | ||
175 | if (is_a<gcond *> (s)) | |
176 | { | |
177 | if (e->flags & EDGE_TRUE_VALUE) | |
178 | r = int_range<2> (boolean_true_node, boolean_true_node); | |
179 | else if (e->flags & EDGE_FALSE_VALUE) | |
180 | r = int_range<2> (boolean_false_node, boolean_false_node); | |
181 | else | |
182 | gcc_unreachable (); | |
183 | return s; | |
184 | } | |
185 | ||
186 | gcc_checking_assert (is_a<gswitch *> (s)); | |
187 | gswitch *sw = as_a<gswitch *> (s); | |
188 | tree type = TREE_TYPE (gimple_switch_index (sw)); | |
189 | ||
190 | if (!irange::supports_type_p (type)) | |
191 | return NULL; | |
192 | ||
193 | if (get_edge_range (r, sw, e)) | |
194 | return s; | |
195 | ||
196 | return NULL; | |
197 | } |