1 // RUN: %clang_cc1 -fsyntax-only -verify=cxx11 -std=c++11 -Wno-unused -Wno-uninitialized \
2 // RUN: -Wunsequenced -Wno-c++17-extensions -Wno-c++14-extensions %s
3 // RUN: %clang_cc1 -fsyntax-only -verify=cxx17 -std=c++17 -Wno-unused -Wno-uninitialized \
4 // RUN: -Wunsequenced -Wno-c++17-extensions -Wno-c++14-extensions %s
5
6 int f(int, int = 0);
7 int g1();
8 int g2(int);
9
10 struct A {
11 int x, y;
12 };
13 struct S {
14 S(int, int);
15 int n;
16 };
17
test()18 void test() {
19 int a;
20 int xs[10];
21 ++a = 0; // ok
22 a + ++a; // cxx11-warning {{unsequenced modification and access to 'a'}}
23 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
24 a = ++a; // ok
25 a + a++; // cxx11-warning {{unsequenced modification and access to 'a'}}
26 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
27 a = a++; // cxx11-warning {{multiple unsequenced modifications to 'a'}}
28 ++ ++a; // ok
29 (a++, a++); // ok
30 ++a + ++a; // cxx11-warning {{multiple unsequenced modifications to 'a'}}
31 // cxx17-warning@-1 {{multiple unsequenced modifications to 'a'}}
32 a++ + a++; // cxx11-warning {{multiple unsequenced modifications to 'a'}}
33 // cxx17-warning@-1 {{multiple unsequenced modifications to 'a'}}
34 (a++, a) = 0; // ok, increment is sequenced before value computation of LHS
35 a = xs[++a]; // ok
36 a = xs[a++]; // cxx11-warning {{multiple unsequenced modifications to 'a'}}
37 (a ? xs[0] : xs[1]) = ++a; // cxx11-warning {{unsequenced modification and access to 'a'}}
38 a = (++a, ++a); // ok
39 a = (a++, ++a); // ok
40 a = (a++, a++); // cxx11-warning {{multiple unsequenced modifications to 'a'}}
41 f(a, a); // ok
42 f(a = 0, a); // cxx11-warning {{unsequenced modification and access to 'a'}}
43 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
44 f(a, a += 0); // cxx11-warning {{unsequenced modification and access to 'a'}}
45 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
46 f(a = 0, a = 0); // cxx11-warning {{multiple unsequenced modifications to 'a'}}
47 // cxx17-warning@-1 {{multiple unsequenced modifications to 'a'}}
48 a = f(++a); // ok
49 a = f(a++); // ok
50 a = f(++a, a++); // cxx11-warning {{multiple unsequenced modifications to 'a'}}
51 // cxx17-warning@-1 {{multiple unsequenced modifications to 'a'}}
52
53 // Compound assignment "A OP= B" is equivalent to "A = A OP B" except that A
54 // is evaluated only once.
55 (++a, a) = 1; // ok
56 (++a, a) += 1; // ok
57 a = ++a; // ok
58 a += ++a; // cxx11-warning {{unsequenced modification and access to 'a'}}
59
60 A agg1 = { a++, a++ }; // ok
61 A agg2 = { a++ + a, a++ }; // cxx11-warning {{unsequenced modification and access to 'a'}}
62 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
63
64 S str1(a++, a++); // cxx11-warning {{multiple unsequenced modifications to 'a'}}
65 // cxx17-warning@-1 {{multiple unsequenced modifications to 'a'}}
66 S str2 = { a++, a++ }; // ok
67 S str3 = { a++ + a, a++ }; // cxx11-warning {{unsequenced modification and access to 'a'}}
68 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
69
70 struct Z { A a; S s; } z = { { ++a, ++a }, { ++a, ++a } }; // ok
71 a = S { ++a, a++ }.n; // ok
72 A { ++a, a++ }.x; // ok
73 a = A { ++a, a++ }.x; // cxx11-warning {{multiple unsequenced modifications to 'a'}}
74 A { ++a, a++ }.x + A { ++a, a++ }.y; // cxx11-warning {{multiple unsequenced modifications to 'a'}}
75 // cxx17-warning@-1 {{multiple unsequenced modifications to 'a'}}
76
77 (xs[2] && (a = 0)) + a; // cxx11-warning {{unsequenced modification and access to 'a'}}
78 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
79 (0 && (a = 0)) + a; // ok
80 (1 && (a = 0)) + a; // cxx11-warning {{unsequenced modification and access to 'a'}}
81 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
82
83 (xs[3] || (a = 0)) + a; // cxx11-warning {{unsequenced modification and access to 'a'}}
84 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
85 (0 || (a = 0)) + a; // cxx11-warning {{unsequenced modification and access to 'a'}}
86 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
87 (1 || (a = 0)) + a; // ok
88
89 (xs[4] ? a : ++a) + a; // cxx11-warning {{unsequenced modification and access to 'a'}}
90 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
91 (0 ? a : ++a) + a; // cxx11-warning {{unsequenced modification and access to 'a'}}
92 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
93 (1 ? a : ++a) + a; // ok
94 (0 ? a : a++) + a; // cxx11-warning {{unsequenced modification and access to 'a'}}
95 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
96 (1 ? a : a++) + a; // ok
97 (xs[5] ? ++a : ++a) + a; // cxx11-warning {{unsequenced modification and access to 'a'}}
98 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
99
100 (++a, xs[6] ? ++a : 0) + a; // cxx11-warning {{unsequenced modification and access to 'a'}}
101 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
102
103 // Here, the read of the fourth 'a' might happen before or after the write to
104 // the second 'a'.
105 a += (a++, a) + a; // cxx11-warning {{unsequenced modification and access to 'a'}}
106 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
107
108 a = a++ && a; // ok
109
110 A *q = &agg1;
111 (q = &agg2)->y = q->x; // cxx11-warning {{unsequenced modification and access to 'q'}}
112
113 // This has undefined behavior if a == 0; otherwise, the side-effect of the
114 // increment is sequenced before the value computation of 'f(a, a)', which is
115 // sequenced before the value computation of the '&&', which is sequenced
116 // before the assignment. We treat the sequencing in '&&' as being
117 // unconditional.
118 a = a++ && f(a, a);
119
120 // This has undefined behavior if a != 0.
121 (a && a++) + a; // cxx11-warning {{unsequenced modification and access to 'a'}}
122 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
123
124 // FIXME: Don't warn here.
125 (xs[7] && ++a) * (!xs[7] && ++a); // cxx11-warning {{multiple unsequenced modifications to 'a'}}
126 // cxx17-warning@-1 {{multiple unsequenced modifications to 'a'}}
127
128 xs[0] = (a = 1, a); // ok
129 (a -= 128) &= 128; // ok
130 ++a += 1; // ok
131
132 xs[8] ? ++a + a++ : 0; // cxx11-warning {{multiple unsequenced modifications to 'a'}}
133 // cxx17-warning@-1 {{multiple unsequenced modifications to 'a'}}
134 xs[8] ? 0 : ++a + a++; // cxx11-warning {{multiple unsequenced modifications to 'a'}}
135 // cxx17-warning@-1 {{multiple unsequenced modifications to 'a'}}
136 xs[8] ? ++a : a++; // no-warning
137 xs[8] ? a+=1 : a+= 2; // no-warning
138 (xs[8] ? a+=1 : a+= 2) = a; // cxx11-warning {{unsequenced modification and access to 'a'}}
139 (xs[8] ? a+=1 : a) = a; // cxx11-warning {{unsequenced modification and access to 'a'}}
140 (xs[8] ? a : a+= 2) = a; // cxx11-warning {{unsequenced modification and access to 'a'}}
141 a = (xs[8] ? a+=1 : a+= 2); // no-warning
142 a += (xs[8] ? a+=1 : a+= 2); // cxx11-warning {{unsequenced modification and access to 'a'}}
143
144 (false ? a+=1 : a) = a; // no-warning
145 (true ? a+=1 : a) = a; // cxx11-warning {{unsequenced modification and access to 'a'}}
146 (false ? a : a+=2) = a; // cxx11-warning {{unsequenced modification and access to 'a'}}
147 (true ? a : a+=2) = a; // no-warning
148
149 xs[8] && (++a + a++); // cxx11-warning {{multiple unsequenced modifications to 'a'}}
150 // cxx17-warning@-1 {{multiple unsequenced modifications to 'a'}}
151 xs[8] || (++a + a++); // cxx11-warning {{multiple unsequenced modifications to 'a'}}
152 // cxx17-warning@-1 {{multiple unsequenced modifications to 'a'}}
153
154 ((a++, false) || (a++, false)); // no-warning PR39779
155 ((a++, true) && (a++, true)); // no-warning PR39779
156
157 int i,j;
158 (i = g1(), false) || (j = g2(i)); // no-warning PR22197
159 (i = g1(), true) && (j = g2(i)); // no-warning PR22197
160
161 (a++, false) || (a++, false) || (a++, false) || (a++, false); // no-warning
162 (a++, true) || (a++, true) || (a++, true) || (a++, true); // no-warning
163 a = ((a++, false) || (a++, false) || (a++, false) || (a++, false)); // no-warning
164 a = ((a++, true) && (a++, true) && (a++, true) && (a++, true)); // no-warning
165 a = ((a++, false) || (a++, false) || (a++, false) || a++); // cxx11-warning {{multiple unsequenced modifications to 'a'}}
166 a = ((a++, true) && (a++, true) && (a++, true) && a++); // cxx11-warning {{multiple unsequenced modifications to 'a'}}
167 a = ((a++, false) || (a++, false) || (a++, false) || (a + a, false)); // no-warning
168 a = ((a++, true) && (a++, true) && (a++, true) && (a + a, true)); // no-warning
169
170 a = (false && a++); // no-warning
171 a = (true && a++); // cxx11-warning {{multiple unsequenced modifications to 'a'}}
172 a = (true && ++a); // no-warning
173 a = (true || a++); // no-warning
174 a = (false || a++); // cxx11-warning {{multiple unsequenced modifications to 'a'}}
175 a = (false || ++a); // no-warning
176
177 (a++) | (a++); // cxx11-warning {{multiple unsequenced modifications to 'a'}}
178 // cxx17-warning@-1 {{multiple unsequenced modifications to 'a'}}
179 (a++) & (a++); // cxx11-warning {{multiple unsequenced modifications to 'a'}}
180 // cxx17-warning@-1 {{multiple unsequenced modifications to 'a'}}
181 (a++) ^ (a++); // cxx11-warning {{multiple unsequenced modifications to 'a'}}
182 // cxx17-warning@-1 {{multiple unsequenced modifications to 'a'}}
183
184 (__builtin_classify_type(++a) ? 1 : 0) + ++a; // ok
185 (__builtin_constant_p(++a) ? 1 : 0) + ++a; // ok
186 (__builtin_object_size(&(++a, a), 0) ? 1 : 0) + ++a; // ok
187 (__builtin_expect(++a, 0) ? 1 : 0) + ++a; // cxx11-warning {{multiple unsequenced modifications to 'a'}}
188 // cxx17-warning@-1 {{multiple unsequenced modifications to 'a'}}
189
190
191 int *p = xs;
192 a = *(a++, p); // no-warning
193 p[(long long unsigned)(p = 0)]; // cxx11-warning {{unsequenced modification and access to 'p'}}
194 (i++, xs)[i++]; // cxx11-warning {{multiple unsequenced modifications to 'i'}}
195 (++i, xs)[++i]; // cxx11-warning {{multiple unsequenced modifications to 'i'}}
196 (i, xs)[++i + ++i]; // cxx11-warning {{multiple unsequenced modifications to 'i'}}
197 // cxx17-warning@-1 {{multiple unsequenced modifications to 'i'}}
198 p++[p == xs]; // cxx11-warning {{unsequenced modification and access to 'p'}}
199 ++p[p++ == xs]; // cxx11-warning {{unsequenced modification and access to 'p'}}
200
201 struct S { int x; } s, *ps = &s;
202 int (S::*PtrMem);
203 (PtrMem = &S::x ,s).*(PtrMem); // cxx11-warning {{unsequenced modification and access to 'PtrMem'}}
204 (PtrMem = &S::x ,s).*(PtrMem = &S::x); // cxx11-warning {{multiple unsequenced modifications to 'PtrMem'}}
205 (PtrMem = &S::x ,ps)->*(PtrMem); // cxx11-warning {{unsequenced modification and access to 'PtrMem'}}
206 (PtrMem = &S::x ,ps)->*(PtrMem = &S::x); // cxx11-warning {{multiple unsequenced modifications to 'PtrMem'}}
207 (PtrMem = nullptr) == (PtrMem = nullptr); // cxx11-warning {{multiple unsequenced modifications to 'PtrMem'}}
208 // cxx17-warning@-1 {{multiple unsequenced modifications to 'PtrMem'}}
209 (PtrMem = nullptr) == PtrMem; // cxx11-warning {{unsequenced modification and access to 'PtrMem'}}
210 // cxx17-warning@-1 {{unsequenced modification and access to 'PtrMem'}}
211
212 i++ << i++; // cxx11-warning {{multiple unsequenced modifications to 'i'}}
213 ++i << ++i; // cxx11-warning {{multiple unsequenced modifications to 'i'}}
214 i++ << i; // cxx11-warning {{unsequenced modification and access to 'i'}}
215 i << i++; // cxx11-warning {{unsequenced modification and access to 'i'}}
216 i++ >> i++; // cxx11-warning {{multiple unsequenced modifications to 'i'}}
217 ++i >> ++i; // cxx11-warning {{multiple unsequenced modifications to 'i'}}
218 i++ >> i; // cxx11-warning {{unsequenced modification and access to 'i'}}
219 i >> i++; // cxx11-warning {{unsequenced modification and access to 'i'}}
220 (i++ << i) + i; // cxx11-warning {{unsequenced modification and access to 'i'}}
221 // cxx17-warning@-1 {{unsequenced modification and access to 'i'}}
222 (i++ << i) << i++; // cxx11-warning {{unsequenced modification and access to 'i'}}
223
224 ++i = i++; // cxx11-warning {{multiple unsequenced modifications to 'i'}}
225 i = i+= 1; // no-warning
226 i = i++ + ++i; // cxx11-warning {{multiple unsequenced modifications to 'i'}}
227 // cxx17-warning@-1 {{multiple unsequenced modifications to 'i'}}
228 ++i += ++i; // cxx11-warning {{multiple unsequenced modifications to 'i'}}
229 ++i += i++; // cxx11-warning {{multiple unsequenced modifications to 'i'}}
230 (i++, i) += ++i; // cxx11-warning {{multiple unsequenced modifications to 'i'}}
231 (i++, i) += i++; // cxx11-warning {{multiple unsequenced modifications to 'i'}}
232 i += i+= 1; // cxx11-warning {{unsequenced modification and access to 'i'}}
233 i += i++; // cxx11-warning {{unsequenced modification and access to 'i'}}
234 i += ++i; // cxx11-warning {{unsequenced modification and access to 'i'}}
235 i -= i++; // cxx11-warning {{unsequenced modification and access to 'i'}}
236 i -= ++i; // cxx11-warning {{unsequenced modification and access to 'i'}}
237 i *= i++; // cxx11-warning {{unsequenced modification and access to 'i'}}
238 i *= ++i; // cxx11-warning {{unsequenced modification and access to 'i'}}
239 i /= i++; // cxx11-warning {{unsequenced modification and access to 'i'}}
240 i /= ++i; // cxx11-warning {{unsequenced modification and access to 'i'}}
241 i %= i++; // cxx11-warning {{unsequenced modification and access to 'i'}}
242 i %= ++i; // cxx11-warning {{unsequenced modification and access to 'i'}}
243 i ^= i++; // cxx11-warning {{unsequenced modification and access to 'i'}}
244 i ^= ++i; // cxx11-warning {{unsequenced modification and access to 'i'}}
245 i |= i++; // cxx11-warning {{unsequenced modification and access to 'i'}}
246 i |= ++i; // cxx11-warning {{unsequenced modification and access to 'i'}}
247 i &= i++; // cxx11-warning {{unsequenced modification and access to 'i'}}
248 i &= ++i; // cxx11-warning {{unsequenced modification and access to 'i'}}
249 i <<= i++; // cxx11-warning {{unsequenced modification and access to 'i'}}
250 i <<= ++i; // cxx11-warning {{unsequenced modification and access to 'i'}}
251 i >>= i++; // cxx11-warning {{unsequenced modification and access to 'i'}}
252 i >>= ++i; // cxx11-warning {{unsequenced modification and access to 'i'}}
253
254 p[i++] = i; // cxx11-warning {{unsequenced modification and access to 'i'}}
255 p[i++] = (i = 42); // cxx11-warning {{multiple unsequenced modifications to 'i'}}
256 p++[i++] = (i = p ? i++ : i++); // cxx11-warning {{unsequenced modification and access to 'p'}}
257 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
258
259 (i++, f)(i++, 42); // cxx11-warning {{multiple unsequenced modifications to 'i'}}
260 (i++ + i++, f)(42, 42); // cxx11-warning {{multiple unsequenced modifications to 'i'}}
261 // cxx17-warning@-1 {{multiple unsequenced modifications to 'i'}}
262 int (*pf)(int, int);
263 (pf = f)(pf != nullptr, pf != nullptr); // cxx11-warning {{unsequenced modification and access to 'pf'}}
264 pf((pf = f) != nullptr, 42); // cxx11-warning {{unsequenced modification and access to 'pf'}}
265 f((pf = f, 42), (pf = f, 42)); // cxx11-warning {{multiple unsequenced modifications to 'pf'}}
266 // cxx17-warning@-1 {{multiple unsequenced modifications to 'pf'}}
267 pf((pf = f) != nullptr, pf == nullptr); // cxx11-warning {{unsequenced modification and access to 'pf'}}
268 // cxx17-warning@-1 {{unsequenced modification and access to 'pf'}}
269 }
270
271 namespace PR20819 {
272 struct foo { void bar(int); };
273 foo get_foo(int);
274
g()275 void g() {
276 int a = 0;
277 get_foo(a).bar(a++); // cxx11-warning {{unsequenced modification and access to 'a'}}
278 }
279 }
280
281 namespace overloaded_operators {
282 struct E {
283 E &operator=(E &);
284 E operator()(E);
285 E operator()(E, E);
286 E operator[](E);
287 } e;
288 // Binary operators with unsequenced operands.
289 E operator+(E,E);
290 E operator-(E,E);
291 E operator*(E,E);
292 E operator/(E,E);
293 E operator%(E,E);
294 E operator^(E,E);
295 E operator&(E,E);
296 E operator|(E,E);
297
298 E operator<(E,E);
299 E operator>(E,E);
300 E operator==(E,E);
301 E operator!=(E,E);
302 E operator>=(E,E);
303 E operator<=(E,E);
304
305 // Binary operators where the RHS is sequenced before the LHS in C++17.
306 E operator+=(E,E);
307 E operator-=(E,E);
308 E operator*=(E,E);
309 E operator/=(E,E);
310 E operator%=(E,E);
311 E operator^=(E,E);
312 E operator&=(E,E);
313 E operator|=(E,E);
314 E operator<<=(E,E);
315 E operator>>=(E,E);
316
317 // Binary operators where the LHS is sequenced before the RHS in C++17.
318 E operator<<(E,E);
319 E operator>>(E,E);
320 E operator&&(E,E);
321 E operator||(E,E);
322 E operator,(E,E);
323 E operator->*(E,E);
324
test()325 void test() {
326 int i = 0;
327 // Binary operators with unsequenced operands.
328 ((void)i++,e) + ((void)i++,e);
329 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
330 // cxx17-warning@-2 {{multiple unsequenced modifications to 'i'}}
331 ((void)i++,e) - ((void)i++,e);
332 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
333 // cxx17-warning@-2 {{multiple unsequenced modifications to 'i'}}
334 ((void)i++,e) * ((void)i++,e);
335 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
336 // cxx17-warning@-2 {{multiple unsequenced modifications to 'i'}}
337 ((void)i++,e) / ((void)i++,e);
338 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
339 // cxx17-warning@-2 {{multiple unsequenced modifications to 'i'}}
340 ((void)i++,e) % ((void)i++,e);
341 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
342 // cxx17-warning@-2 {{multiple unsequenced modifications to 'i'}}
343 ((void)i++,e) ^ ((void)i++,e);
344 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
345 // cxx17-warning@-2 {{multiple unsequenced modifications to 'i'}}
346 ((void)i++,e) & ((void)i++,e);
347 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
348 // cxx17-warning@-2 {{multiple unsequenced modifications to 'i'}}
349 ((void)i++,e) | ((void)i++,e);
350 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
351 // cxx17-warning@-2 {{multiple unsequenced modifications to 'i'}}
352
353 ((void)i++,e) < ((void)i++,e);
354 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
355 // cxx17-warning@-2 {{multiple unsequenced modifications to 'i'}}
356 ((void)i++,e) > ((void)i++,e);
357 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
358 // cxx17-warning@-2 {{multiple unsequenced modifications to 'i'}}
359 ((void)i++,e) == ((void)i++,e);
360 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
361 // cxx17-warning@-2 {{multiple unsequenced modifications to 'i'}}
362 ((void)i++,e) != ((void)i++,e);
363 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
364 // cxx17-warning@-2 {{multiple unsequenced modifications to 'i'}}
365 ((void)i++,e) <= ((void)i++,e);
366 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
367 // cxx17-warning@-2 {{multiple unsequenced modifications to 'i'}}
368 ((void)i++,e) >= ((void)i++,e);
369 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
370 // cxx17-warning@-2 {{multiple unsequenced modifications to 'i'}}
371
372 // Binary operators where the RHS is sequenced before the LHS in C++17.
373 ((void)i++,e) = ((void)i++,e);
374 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
375 ((void)i++,e) += ((void)i++,e);
376 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
377 ((void)i++,e) -= ((void)i++,e);
378 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
379 ((void)i++,e) *= ((void)i++,e);
380 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
381 ((void)i++,e) /= ((void)i++,e);
382 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
383 ((void)i++,e) %= ((void)i++,e);
384 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
385 ((void)i++,e) ^= ((void)i++,e);
386 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
387 ((void)i++,e) &= ((void)i++,e);
388 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
389 ((void)i++,e) |= ((void)i++,e);
390 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
391 ((void)i++,e) <<= ((void)i++,e);
392 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
393 ((void)i++,e) >>= ((void)i++,e);
394 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
395
396 operator+=(((void)i++,e), ((void)i++,e));
397 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
398 // cxx17-warning@-2 {{multiple unsequenced modifications to 'i'}}
399
400 // Binary operators where the LHS is sequenced before the RHS in C++17.
401 ((void)i++,e) << ((void)i++,e);
402 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
403 ((void)i++,e) >> ((void)i++,e);
404 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
405 ((void)i++,e) || ((void)i++,e);
406 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
407 ((void)i++,e) && ((void)i++,e);
408 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
409 ((void)i++,e) , ((void)i++,e);
410 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
411 ((void)i++,e)->*((void)i++,e);
412 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
413
414 operator<<(((void)i++,e), ((void)i++,e));
415 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
416 // cxx17-warning@-2 {{multiple unsequenced modifications to 'i'}}
417
418 ((void)i++,e)[((void)i++,e)];
419 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
420
421 ((void)i++,e)(((void)i++,e));
422 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
423 e(((void)i++,e), ((void)i++,e));
424 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
425 // cxx17-warning@-2 {{multiple unsequenced modifications to 'i'}}
426
427 ((void)i++,e).operator()(((void)i++,e));
428 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
429
430 }
431 }
432
433 namespace PR35340 {
434 struct S {};
435 S &operator<<(S &, int);
436
test()437 void test() {
438 S s;
439 int i = 0;
440 s << i++ << i++;
441 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
442
443 operator<<(operator<<(s, i++), i++);
444 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
445 // cxx17-warning@-2 {{multiple unsequenced modifications to 'i'}}
446 }
447 }
448
449 namespace members {
450
451 struct S1 {
452 unsigned bf1 : 2;
453 unsigned bf2 : 2;
454 unsigned a;
455 unsigned b;
456 static unsigned x;
457 void member_f(S1 &s);
458 };
459
member_f(S1 & s)460 void S1::member_f(S1 &s) {
461 ++a + ++a; // cxx11-warning {{multiple unsequenced modifications to 'a'}}
462 // cxx17-warning@-1 {{multiple unsequenced modifications to 'a'}}
463 a + ++a; // cxx11-warning {{unsequenced modification and access to 'a'}}
464 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
465 ++a + ++b; // no-warning
466 a + ++b; // no-warning
467
468 // TODO: Warn here.
469 ++s.a + ++s.a; // no-warning TODO {{multiple unsequenced modifications to}}
470 s.a + ++s.a; // no-warning TODO {{unsequenced modification and access to}}
471 ++s.a + ++s.b; // no-warning
472 s.a + ++s.b; // no-warning
473
474 ++a + ++s.a; // no-warning
475 a + ++s.a; // no-warning
476 ++a + ++s.b; // no-warning
477 a + ++s.b; // no-warning
478
479 // TODO Warn here for bit-fields in the same memory location.
480 ++bf1 + ++bf1; // cxx11-warning {{multiple unsequenced modifications to 'bf1'}}
481 // cxx17-warning@-1 {{multiple unsequenced modifications to 'bf1'}}
482 bf1 + ++bf1; // cxx11-warning {{unsequenced modification and access to 'bf1'}}
483 // cxx17-warning@-1 {{unsequenced modification and access to 'bf1'}}
484 ++bf1 + ++bf2; // no-warning TODO {{multiple unsequenced modifications to}}
485 bf1 + ++bf2; // no-warning TODO {{unsequenced modification and access to}}
486
487 // TODO Warn here for bit-fields in the same memory location.
488 ++s.bf1 + ++s.bf1; // no-warning TODO {{multiple unsequenced modifications to}}
489 s.bf1 + ++s.bf1; // no-warning TODO {{unsequenced modification and access to}}
490 ++s.bf1 + ++s.bf2; // no-warning TODO {{multiple unsequenced modifications to}}
491 s.bf1 + ++s.bf2; // no-warning TODO {{unsequenced modification and access to}}
492
493 ++bf1 + ++s.bf1; // no-warning
494 bf1 + ++s.bf1; // no-warning
495 ++bf1 + ++s.bf2; // no-warning
496 bf1 + ++s.bf2; // no-warning
497
498 struct Der : S1 {};
499 Der d;
500 Der &d_ref = d;
501 S1 &s1_ref = d_ref;
502
503 ++s1_ref.a + ++d_ref.a; // no-warning TODO {{multiple unsequenced modifications to member 'a' of 'd'}}
504 ++s1_ref.a + d_ref.a; // no-warning TODO {{unsequenced modification and access to member 'a' of 'd'}}
505 ++s1_ref.a + ++d_ref.b; // no-warning
506 ++s1_ref.a + d_ref.b; // no-warning
507
508 ++x + ++x; // cxx11-warning {{multiple unsequenced modifications to 'x'}}
509 // cxx17-warning@-1 {{multiple unsequenced modifications to 'x'}}
510 ++x + x; // cxx11-warning {{unsequenced modification and access to 'x'}}
511 // cxx17-warning@-1 {{unsequenced modification and access to 'x'}}
512 ++s.x + x; // no-warning TODO {{unsequenced modification and access to static member 'x' of 'S1'}}
513 ++this->x + x; // cxx11-warning {{unsequenced modification and access to 'x'}}
514 // cxx17-warning@-1 {{unsequenced modification and access to 'x'}}
515 ++d_ref.x + ++S1::x; // no-warning TODO {{unsequenced modification and access to static member 'x' of 'S1'}}
516 }
517
518 struct S2 {
519 union { unsigned x, y; };
520 void f2();
521 };
522
f2()523 void S2::f2() {
524 ++x + ++x; // no-warning TODO {{multiple unsequenced modifications to}}
525 x + ++x; // no-warning TODO {{unsequenced modification and access to}}
526 ++x + ++y; // no-warning
527 x + ++y; // no-warning
528 }
529
f2(S2 & s)530 void f2(S2 &s) {
531 ++s.x + ++s.x; // no-warning TODO {{multiple unsequenced modifications to}}
532 s.x + ++s.x; // no-warning TODO {{unsequenced modification and access to}}
533 ++s.x + ++s.y; // no-warning
534 s.x + ++s.y; // no-warning
535 }
536
537 struct S3 {
538 union {
539 union {
540 unsigned x;
541 };
542 };
543 unsigned y;
544 void f3();
545 };
546
f3()547 void S3::f3() {
548 ++x + ++x; // no-warning TODO {{multiple unsequenced modifications to}}
549 x + ++x; // no-warning TODO {{unsequenced modification and access to}}
550 ++x + ++y; // no-warning
551 x + ++y; // no-warning
552 }
553
f3(S3 & s)554 void f3(S3 &s) {
555 ++s.x + ++s.x; // no-warning TODO {{multiple unsequenced modifications to}}
556 s.x + ++s.x; // no-warning TODO {{unsequenced modification and access to}}
557 ++s.x + ++s.y; // no-warning
558 s.x + ++s.y; // no-warning
559 }
560
561 struct S4 : S3 {
562 unsigned y;
563 void f4();
564 };
565
f4()566 void S4::f4() {
567 ++x + ++x; // no-warning TODO {{multiple unsequenced modifications to}}
568 x + ++x; // no-warning TODO {{unsequenced modification and access to}}
569 ++x + ++y; // no-warning
570 x + ++y; // no-warning
571 ++S3::y + ++y; // no-warning
572 S3::y + ++y; // no-warning
573 }
574
f4(S4 & s)575 void f4(S4 &s) {
576 ++s.x + ++s.x; // no-warning TODO {{multiple unsequenced modifications to}}
577 s.x + ++s.x; // no-warning TODO {{unsequenced modification and access to}}
578 ++s.x + ++s.y; // no-warning
579 s.x + ++s.y; // no-warning
580 ++s.S3::y + ++s.y; // no-warning
581 s.S3::y + ++s.y; // no-warning
582 }
583
584 static union {
585 unsigned Ux;
586 unsigned Uy;
587 };
588
f5()589 void f5() {
590 ++Ux + ++Ux; // no-warning TODO {{multiple unsequenced modifications to}}
591 Ux + ++Ux; // no-warning TODO {{unsequenced modification and access to}}
592 ++Ux + ++Uy; // no-warning
593 Ux + ++Uy; // no-warning
594 }
595
f6()596 void f6() {
597 struct S { unsigned x, y; } s;
598 ++s.x + ++s.x; // no-warning TODO {{multiple unsequenced modifications to}}
599 s.x + ++s.x; // no-warning TODO {{unsequenced modification and access to}}
600 ++s.x + ++s.y; // no-warning
601 s.x + ++s.y; // no-warning
602
603 struct { unsigned x, y; } t;
604 ++t.x + ++t.x; // no-warning TODO {{multiple unsequenced modifications to}}
605 t.x + ++t.x; // no-warning TODO {{unsequenced modification and access to}}
606 ++t.x + ++t.y; // no-warning
607 t.x + ++t.y; // no-warning
608 }
609
610 } // namespace members
611
612 namespace references {
reference_f()613 void reference_f() {
614 // TODO: Check that we can see through references.
615 // For now this is completely unhandled.
616 int a;
617 int xs[10];
618 int &b = a;
619 int &c = b;
620 int &ra1 = c;
621 int &ra2 = b;
622 int other;
623
624 ++ra1 + ++ra2; // no-warning TODO {{multiple unsequenced modifications to}}
625 ra1 + ++ra2; // no-warning TODO {{unsequenced modification and access to}}
626 ++ra1 + ++other; // no-warning
627 ra1 + ++other; // no-warning
628
629 // Make sure we handle reference cycles.
630 int &ref_cycle = ref_cycle;
631 ++ref_cycle + ++ref_cycle; // cxx11-warning {{multiple unsequenced modifications to 'ref_cycle'}}
632 // cxx17-warning@-1 {{multiple unsequenced modifications to 'ref_cycle'}}
633 ref_cycle + ++ref_cycle; // cxx11-warning {{unsequenced modification and access to 'ref_cycle'}}
634 // cxx17-warning@-1 {{unsequenced modification and access to 'ref_cycle'}}
635 }
636 } // namespace references
637
638 namespace std {
639 using size_t = decltype(sizeof(0));
640 template<typename> struct tuple_size;
641 template<size_t, typename> struct tuple_element { using type = int; };
642 }
643 namespace bindings {
644
645 struct A { int x, y; };
646 typedef int B[2];
647 struct C { template<int> int get(); };
648 struct D : A {};
649
650 } // namespace bindings
651 template<> struct std::tuple_size<bindings::C> { enum { value = 2 }; };
652 namespace bindings {
testa()653 void testa() {
654 A a;
655 {
656 auto [x, y] = a;
657 ++x + ++x; // cxx11-warning {{multiple unsequenced modifications to 'x'}}
658 // cxx17-warning@-1 {{multiple unsequenced modifications to 'x'}}
659 ++x + x; // cxx11-warning {{unsequenced modification and access to 'x'}}
660 // cxx17-warning@-1 {{unsequenced modification and access to 'x'}}
661 ++x + ++y; // no-warning
662 ++x + y; // no-warning
663 ++x + ++a.x; // no-warning
664 ++x + a.x; // no-warning
665 }
666 {
667 auto &[x, y] = a;
668 ++x + ++x; // cxx11-warning {{multiple unsequenced modifications to 'x'}}
669 // cxx17-warning@-1 {{multiple unsequenced modifications to 'x'}}
670 ++x + x; // cxx11-warning {{unsequenced modification and access to 'x'}}
671 // cxx17-warning@-1 {{unsequenced modification and access to 'x'}}
672 ++x + ++y; // no-warning
673 ++x + y; // no-warning
674 ++x + ++a.x; // no-warning TODO
675 ++x + a.x; // no-warning TODO
676 }
677 }
testb()678 void testb() {
679 B b;
680 {
681 auto [x, y] = b;
682 ++x + ++x; // cxx11-warning {{multiple unsequenced modifications to 'x'}}
683 // cxx17-warning@-1 {{multiple unsequenced modifications to 'x'}}
684 ++x + x; // cxx11-warning {{unsequenced modification and access to 'x'}}
685 // cxx17-warning@-1 {{unsequenced modification and access to 'x'}}
686 ++x + ++y; // no-warning
687 ++x + y; // no-warning
688 ++x + ++b[0]; // no-warning
689 ++x + b[0]; // no-warning
690 }
691 {
692 auto &[x, y] = b;
693 ++x + ++x; // cxx11-warning {{multiple unsequenced modifications to 'x'}}
694 // cxx17-warning@-1 {{multiple unsequenced modifications to 'x'}}
695 ++x + x; // cxx11-warning {{unsequenced modification and access to 'x'}}
696 // cxx17-warning@-1 {{unsequenced modification and access to 'x'}}
697 ++x + ++y; // no-warning
698 ++x + y; // no-warning
699 ++x + ++b[0]; // no-warning TODO
700 ++x + b[0]; // no-warning TODO
701 }
702 }
testc()703 void testc() {
704 C c;
705 {
706 auto [x, y] = c;
707 ++x + ++x; // cxx11-warning {{multiple unsequenced modifications to 'x'}}
708 // cxx17-warning@-1 {{multiple unsequenced modifications to 'x'}}
709 ++x + x; // cxx11-warning {{unsequenced modification and access to 'x'}}
710 // cxx17-warning@-1 {{unsequenced modification and access to 'x'}}
711 ++x + ++y; // no-warning
712 ++x + y; // no-warning
713 }
714 {
715 auto &[x, y] = c;
716 ++x + ++x; // cxx11-warning {{multiple unsequenced modifications to 'x'}}
717 // cxx17-warning@-1 {{multiple unsequenced modifications to 'x'}}
718 ++x + x; // cxx11-warning {{unsequenced modification and access to 'x'}}
719 // cxx17-warning@-1 {{unsequenced modification and access to 'x'}}
720 ++x + ++y; // no-warning
721 ++x + y; // no-warning
722 }
723 }
testd()724 void testd() {
725 D d;
726 {
727 auto [x, y] = d;
728 ++x + ++x; // cxx11-warning {{multiple unsequenced modifications to 'x'}}
729 // cxx17-warning@-1 {{multiple unsequenced modifications to 'x'}}
730 ++x + x; // cxx11-warning {{unsequenced modification and access to 'x'}}
731 // cxx17-warning@-1 {{unsequenced modification and access to 'x'}}
732 ++x + ++y; // no-warning
733 ++x + y; // no-warning
734 ++x + ++d.x; // no-warning
735 ++x + d.x; // no-warning
736 }
737 {
738 auto &[x, y] = d;
739 ++x + ++x; // cxx11-warning {{multiple unsequenced modifications to 'x'}}
740 // cxx17-warning@-1 {{multiple unsequenced modifications to 'x'}}
741 ++x + x; // cxx11-warning {{unsequenced modification and access to 'x'}}
742 // cxx17-warning@-1 {{unsequenced modification and access to 'x'}}
743 ++x + ++y; // no-warning
744 ++x + y; // no-warning
745 ++x + ++d.x; // no-warning TODO
746 ++x + d.x; // no-warning TODO
747 }
748 }
749 } // namespace bindings
750
751 namespace templates {
752
753 template <typename T>
754 struct Bar {
gettemplates::Bar755 T get() { return 0; }
756 };
757
758 template <typename X>
759 struct Foo {
760 int Run();
761 Bar<int> bar;
762 };
763
764 enum E {e1, e2};
765 bool operator&&(E, E);
766
767 void foo(int, int);
768
769 template <typename X>
Run()770 int Foo<X>::Run() {
771 char num = 0;
772
773 // Before instantiation, Clang may consider the builtin operator here as
774 // unresolved function calls, and treat the arguments as unordered when
775 // the builtin operator evaluatation is well-ordered. Waiting until
776 // instantiation to check these expressions will prevent false positives.
777 if ((num = bar.get()) < 5 && num < 10) { }
778 if ((num = bar.get()) < 5 || num < 10) { }
779 if (static_cast<E>((num = bar.get()) < 5) || static_cast<E>(num < 10)) { }
780
781 if (static_cast<E>((num = bar.get()) < 5) && static_cast<E>(num < 10)) { }
782 // cxx11-warning@-1 {{unsequenced modification and access to 'num'}}
783
784 foo(num++, num++);
785 // cxx11-warning@-1 {{multiple unsequenced modifications to 'num'}}
786 // cxx17-warning@-2 {{multiple unsequenced modifications to 'num'}}
787 return 1;
788 }
789
790 int x = Foo<int>().Run();
791 // cxx11-note@-1 {{in instantiation of member function 'templates::Foo<int>::Run'}}
792 // cxx17-note@-2 {{in instantiation of member function 'templates::Foo<int>::Run'}}
793
794
795 template <typename T>
Run2()796 int Run2() {
797 T t = static_cast<T>(0);
798 return (t = static_cast<T>(1)) && t;
799 // cxx11-warning@-1 {{unsequenced modification and access to 't'}}
800 }
801
802 int y = Run2<bool>();
803 int z = Run2<E>();
804 // cxx11-note@-1{{in instantiation of function template specialization 'templates::Run2<templates::E>' requested here}}
805
806 template <typename T> int var = sizeof(T);
test_var()807 void test_var() {
808 var<int>++ + var<int>++; // cxx11-warning {{multiple unsequenced modifications to 'var<int>'}}
809 // cxx17-warning@-1 {{multiple unsequenced modifications to 'var<int>'}}
810 var<int>++ + var<int>; // cxx11-warning {{unsequenced modification and access to 'var<int>'}}
811 // cxx17-warning@-1 {{unsequenced modification and access to 'var<int>'}}
812 int &r = var<int>;
813 r++ + var<int>++; // no-warning TODO {{multiple unsequenced modifications to 'var<int>'}}
814 r++ + var<long>++; // no-warning
815 }
816
817 } // namespace templates
818