1 /* This file contains routines to construct and validate Cilk Plus
2 constructs within the C and C++ front ends.
3
4 Copyright (C) 2013-2016 Free Software Foundation, Inc.
5 Contributed by Aldy Hernandez <aldyh@redhat.com>.
6
7 This file is part of GCC.
8
9 GCC is free software; you can redistribute it and/or modify it
10 under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3, or (at your option)
12 any later version.
13
14 GCC is distributed in the hope that it will be useful, but
15 WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 General Public License for more details.
18
19 You should have received a copy of the GNU General Public License
20 along with GCC; see the file COPYING3. If not see
21 <http://www.gnu.org/licenses/>. */
22
23 #include "config.h"
24 #include "system.h"
25 #include "coretypes.h"
26 #include "c-common.h"
27
28 /* Validate the body of a _Cilk_for construct or a <#pragma simd> for
29 loop.
30
31 Returns true if there were no errors, false otherwise. */
32
33 bool
c_check_cilk_loop(location_t loc,tree decl)34 c_check_cilk_loop (location_t loc, tree decl)
35 {
36 if (TREE_THIS_VOLATILE (decl))
37 {
38 error_at (loc, "iteration variable cannot be volatile");
39 return false;
40 }
41 return true;
42 }
43
44 /* Validate and emit code for <#pragma simd> clauses. */
45
46 tree
c_finish_cilk_clauses(tree clauses)47 c_finish_cilk_clauses (tree clauses)
48 {
49 for (tree c = clauses; c; c = OMP_CLAUSE_CHAIN (c))
50 {
51 tree prev = clauses;
52
53 /* If a variable appears in a linear clause it cannot appear in
54 any other OMP clause. */
55 if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_LINEAR)
56 for (tree c2 = clauses; c2; c2 = OMP_CLAUSE_CHAIN (c2))
57 {
58 if (c == c2)
59 continue;
60 enum omp_clause_code code = OMP_CLAUSE_CODE (c2);
61
62 switch (code)
63 {
64 case OMP_CLAUSE_LINEAR:
65 case OMP_CLAUSE_PRIVATE:
66 case OMP_CLAUSE_FIRSTPRIVATE:
67 case OMP_CLAUSE_LASTPRIVATE:
68 case OMP_CLAUSE_REDUCTION:
69 break;
70
71 case OMP_CLAUSE_SAFELEN:
72 goto next;
73
74 default:
75 gcc_unreachable ();
76 }
77
78 if (OMP_CLAUSE_DECL (c) == OMP_CLAUSE_DECL (c2))
79 {
80 error_at (OMP_CLAUSE_LOCATION (c2),
81 "variable appears in more than one clause");
82 inform (OMP_CLAUSE_LOCATION (c),
83 "other clause defined here");
84 // Remove problematic clauses.
85 OMP_CLAUSE_CHAIN (prev) = OMP_CLAUSE_CHAIN (c2);
86 }
87 next:
88 prev = c2;
89 }
90 }
91 return clauses;
92 }
93
94 /* Calculate number of iterations of CILK_FOR. */
95
96 tree
cilk_for_number_of_iterations(tree cilk_for)97 cilk_for_number_of_iterations (tree cilk_for)
98 {
99 tree t, v, n1, n2, step, type, init, cond, incr, itype;
100 enum tree_code cond_code;
101 location_t loc = EXPR_LOCATION (cilk_for);
102
103 init = TREE_VEC_ELT (OMP_FOR_INIT (cilk_for), 0);
104 v = TREE_OPERAND (init, 0);
105 cond = TREE_VEC_ELT (OMP_FOR_COND (cilk_for), 0);
106 incr = TREE_VEC_ELT (OMP_FOR_INCR (cilk_for), 0);
107 type = TREE_TYPE (v);
108
109 gcc_assert (TREE_CODE (TREE_TYPE (v)) == INTEGER_TYPE
110 || TREE_CODE (TREE_TYPE (v)) == POINTER_TYPE);
111 n1 = TREE_OPERAND (init, 1);
112 cond_code = TREE_CODE (cond);
113 n2 = TREE_OPERAND (cond, 1);
114 switch (cond_code)
115 {
116 case LT_EXPR:
117 case GT_EXPR:
118 case NE_EXPR:
119 break;
120 case LE_EXPR:
121 if (POINTER_TYPE_P (TREE_TYPE (n2)))
122 n2 = fold_build_pointer_plus_hwi_loc (loc, n2, 1);
123 else
124 n2 = fold_build2_loc (loc, PLUS_EXPR, TREE_TYPE (n2), n2,
125 build_int_cst (TREE_TYPE (n2), 1));
126 cond_code = LT_EXPR;
127 break;
128 case GE_EXPR:
129 if (POINTER_TYPE_P (TREE_TYPE (n2)))
130 n2 = fold_build_pointer_plus_hwi_loc (loc, n2, -1);
131 else
132 n2 = fold_build2_loc (loc, MINUS_EXPR, TREE_TYPE (n2), n2,
133 build_int_cst (TREE_TYPE (n2), 1));
134 cond_code = GT_EXPR;
135 break;
136 default:
137 gcc_unreachable ();
138 }
139
140 step = NULL_TREE;
141 switch (TREE_CODE (incr))
142 {
143 case PREINCREMENT_EXPR:
144 case POSTINCREMENT_EXPR:
145 step = build_int_cst (TREE_TYPE (v), 1);
146 break;
147 case PREDECREMENT_EXPR:
148 case POSTDECREMENT_EXPR:
149 step = build_int_cst (TREE_TYPE (v), -1);
150 break;
151 case MODIFY_EXPR:
152 t = TREE_OPERAND (incr, 1);
153 gcc_assert (TREE_OPERAND (t, 0) == v);
154 switch (TREE_CODE (t))
155 {
156 case PLUS_EXPR:
157 step = TREE_OPERAND (t, 1);
158 break;
159 case POINTER_PLUS_EXPR:
160 step = fold_convert (ssizetype, TREE_OPERAND (t, 1));
161 break;
162 case MINUS_EXPR:
163 step = TREE_OPERAND (t, 1);
164 step = fold_build1_loc (loc, NEGATE_EXPR, TREE_TYPE (step), step);
165 break;
166 default:
167 gcc_unreachable ();
168 }
169 break;
170 default:
171 gcc_unreachable ();
172 }
173
174 itype = type;
175 if (POINTER_TYPE_P (itype))
176 itype = signed_type_for (itype);
177 if (cond_code == NE_EXPR)
178 {
179 /* For NE_EXPR, we need to find out if the iterator increases
180 or decreases from whether step is positive or negative. */
181 tree stype = itype;
182 if (TYPE_UNSIGNED (stype))
183 stype = signed_type_for (stype);
184 cond = fold_build2_loc (loc, GE_EXPR, boolean_type_node,
185 fold_convert_loc (loc, stype, step),
186 build_int_cst (stype, 0));
187 t = fold_build3_loc (loc, COND_EXPR, itype, cond,
188 build_int_cst (itype, -1),
189 build_int_cst (itype, 1));
190 }
191 else
192 t = build_int_cst (itype, (cond_code == LT_EXPR ? -1 : 1));
193 t = fold_build2_loc (loc, PLUS_EXPR, itype,
194 fold_convert_loc (loc, itype, step), t);
195 t = fold_build2_loc (loc, PLUS_EXPR, itype, t,
196 fold_convert_loc (loc, itype, n2));
197 t = fold_build2_loc (loc, MINUS_EXPR, itype, t,
198 fold_convert_loc (loc, itype, n1));
199 if (TYPE_UNSIGNED (itype) && cond_code == GT_EXPR)
200 t = fold_build2_loc (loc, TRUNC_DIV_EXPR, itype,
201 fold_build1_loc (loc, NEGATE_EXPR, itype, t),
202 fold_build1_loc (loc, NEGATE_EXPR, itype,
203 fold_convert_loc (loc, itype,
204 step)));
205 else if (TYPE_UNSIGNED (itype) && cond_code == NE_EXPR)
206 {
207 tree t1
208 = fold_build2_loc (loc, TRUNC_DIV_EXPR, itype, t,
209 fold_convert_loc (loc, itype, step));
210 tree t2
211 = fold_build2_loc (loc, TRUNC_DIV_EXPR, itype,
212 fold_build1_loc (loc, NEGATE_EXPR, itype, t),
213 fold_build1_loc (loc, NEGATE_EXPR, itype,
214 fold_convert_loc (loc, itype,
215 step)));
216 t = fold_build3_loc (loc, COND_EXPR, itype, cond, t1, t2);
217 }
218 else
219 t = fold_build2_loc (loc, TRUNC_DIV_EXPR, itype, t,
220 fold_convert_loc (loc, itype, step));
221 cond = fold_build2_loc (loc, cond_code, boolean_type_node, n1, n2);
222 t = fold_build3_loc (loc, COND_EXPR, itype, cond, t,
223 build_int_cst (itype, 0));
224 return t;
225 }
226