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
18 // TODO: Implement the C++17 sequencing rules.
test()19 void test() {
20 int a;
21 int xs[10];
22 ++a = 0; // ok
23 a + ++a; // cxx11-warning {{unsequenced modification and access to 'a'}}
24 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
25 a = ++a; // ok
26 a + a++; // cxx11-warning {{unsequenced modification and access to 'a'}}
27 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
28 a = a++; // cxx11-warning {{multiple unsequenced modifications to 'a'}}
29 ++ ++a; // ok
30 (a++, a++); // ok
31 ++a + ++a; // cxx11-warning {{multiple unsequenced modifications to 'a'}}
32 // cxx17-warning@-1 {{multiple unsequenced modifications to 'a'}}
33 a++ + a++; // cxx11-warning {{multiple unsequenced modifications to 'a'}}
34 // cxx17-warning@-1 {{multiple unsequenced modifications to 'a'}}
35 (a++, a) = 0; // ok, increment is sequenced before value computation of LHS
36 a = xs[++a]; // ok
37 a = xs[a++]; // cxx11-warning {{multiple unsequenced modifications to 'a'}}
38 (a ? xs[0] : xs[1]) = ++a; // cxx11-warning {{unsequenced modification and access to 'a'}}
39 a = (++a, ++a); // ok
40 a = (a++, ++a); // ok
41 a = (a++, a++); // cxx11-warning {{multiple unsequenced modifications to 'a'}}
42 f(a, a); // ok
43 f(a = 0, a); // cxx11-warning {{unsequenced modification and access to 'a'}}
44 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
45 f(a, a += 0); // cxx11-warning {{unsequenced modification and access to 'a'}}
46 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
47 f(a = 0, a = 0); // cxx11-warning {{multiple unsequenced modifications to 'a'}}
48 // cxx17-warning@-1 {{multiple unsequenced modifications to 'a'}}
49 a = f(++a); // ok
50 a = f(a++); // ok
51 a = f(++a, a++); // cxx11-warning {{multiple unsequenced modifications to 'a'}}
52 // cxx17-warning@-1 {{multiple unsequenced modifications to 'a'}}
53
54 // Compound assignment "A OP= B" is equivalent to "A = A OP B" except that A
55 // is evaluated only once.
56 (++a, a) = 1; // ok
57 (++a, a) += 1; // ok
58 a = ++a; // ok
59 a += ++a; // cxx11-warning {{unsequenced modification and access to 'a'}}
60
61 A agg1 = { a++, a++ }; // ok
62 A agg2 = { a++ + a, a++ }; // cxx11-warning {{unsequenced modification and access to 'a'}}
63 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
64
65 S str1(a++, a++); // cxx11-warning {{multiple unsequenced modifications to 'a'}}
66 // cxx17-warning@-1 {{multiple unsequenced modifications to 'a'}}
67 S str2 = { a++, a++ }; // ok
68 S str3 = { a++ + a, a++ }; // cxx11-warning {{unsequenced modification and access to 'a'}}
69 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
70
71 struct Z { A a; S s; } z = { { ++a, ++a }, { ++a, ++a } }; // ok
72 a = S { ++a, a++ }.n; // ok
73 A { ++a, a++ }.x; // ok
74 a = A { ++a, a++ }.x; // cxx11-warning {{multiple unsequenced modifications to 'a'}}
75 A { ++a, a++ }.x + A { ++a, a++ }.y; // cxx11-warning {{multiple unsequenced modifications to 'a'}}
76 // cxx17-warning@-1 {{multiple unsequenced modifications to 'a'}}
77
78 (xs[2] && (a = 0)) + a; // cxx11-warning {{unsequenced modification and access to 'a'}}
79 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
80 (0 && (a = 0)) + a; // ok
81 (1 && (a = 0)) + a; // cxx11-warning {{unsequenced modification and access to 'a'}}
82 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
83
84 (xs[3] || (a = 0)) + a; // cxx11-warning {{unsequenced modification and access to 'a'}}
85 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
86 (0 || (a = 0)) + a; // cxx11-warning {{unsequenced modification and access to 'a'}}
87 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
88 (1 || (a = 0)) + a; // ok
89
90 (xs[4] ? a : ++a) + a; // cxx11-warning {{unsequenced modification and access to 'a'}}
91 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
92 (0 ? a : ++a) + a; // cxx11-warning {{unsequenced modification and access to 'a'}}
93 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
94 (1 ? a : ++a) + a; // ok
95 (0 ? a : a++) + a; // cxx11-warning {{unsequenced modification and access to 'a'}}
96 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
97 (1 ? a : a++) + a; // ok
98 (xs[5] ? ++a : ++a) + a; // cxx11-warning {{unsequenced modification and access to 'a'}}
99 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
100
101 (++a, xs[6] ? ++a : 0) + a; // cxx11-warning {{unsequenced modification and access to 'a'}}
102 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
103
104 // Here, the read of the fourth 'a' might happen before or after the write to
105 // the second 'a'.
106 a += (a++, a) + a; // cxx11-warning {{unsequenced modification and access to 'a'}}
107 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
108
109 a = a++ && a; // ok
110
111 A *q = &agg1;
112 (q = &agg2)->y = q->x; // cxx11-warning {{unsequenced modification and access to 'q'}}
113
114 // This has undefined behavior if a == 0; otherwise, the side-effect of the
115 // increment is sequenced before the value computation of 'f(a, a)', which is
116 // sequenced before the value computation of the '&&', which is sequenced
117 // before the assignment. We treat the sequencing in '&&' as being
118 // unconditional.
119 a = a++ && f(a, a);
120
121 // This has undefined behavior if a != 0.
122 (a && a++) + a; // cxx11-warning {{unsequenced modification and access to 'a'}}
123 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
124
125 // FIXME: Don't warn here.
126 (xs[7] && ++a) * (!xs[7] && ++a); // cxx11-warning {{multiple unsequenced modifications to 'a'}}
127 // cxx17-warning@-1 {{multiple unsequenced modifications to 'a'}}
128
129 xs[0] = (a = 1, a); // ok
130 (a -= 128) &= 128; // ok
131 ++a += 1; // ok
132
133 xs[8] ? ++a + a++ : 0; // cxx11-warning {{multiple unsequenced modifications to 'a'}}
134 // cxx17-warning@-1 {{multiple unsequenced modifications to 'a'}}
135 xs[8] ? 0 : ++a + a++; // cxx11-warning {{multiple unsequenced modifications to 'a'}}
136 // cxx17-warning@-1 {{multiple unsequenced modifications to 'a'}}
137 xs[8] ? ++a : a++; // no-warning
138 xs[8] ? a+=1 : a+= 2; // no-warning
139 (xs[8] ? a+=1 : a+= 2) = a; // cxx11-warning {{unsequenced modification and access to 'a'}}
140 (xs[8] ? a+=1 : a) = a; // cxx11-warning {{unsequenced modification and access to 'a'}}
141 (xs[8] ? a : a+= 2) = a; // cxx11-warning {{unsequenced modification and access to 'a'}}
142 a = (xs[8] ? a+=1 : a+= 2); // no-warning
143 a += (xs[8] ? a+=1 : a+= 2); // cxx11-warning {{unsequenced modification and access to 'a'}}
144
145 (false ? a+=1 : a) = a; // no-warning
146 (true ? a+=1 : a) = a; // cxx11-warning {{unsequenced modification and access to 'a'}}
147 (false ? a : a+=2) = a; // cxx11-warning {{unsequenced modification and access to 'a'}}
148 (true ? a : a+=2) = a; // no-warning
149
150 xs[8] && (++a + a++); // cxx11-warning {{multiple unsequenced modifications to 'a'}}
151 // cxx17-warning@-1 {{multiple unsequenced modifications to 'a'}}
152 xs[8] || (++a + a++); // cxx11-warning {{multiple unsequenced modifications to 'a'}}
153 // cxx17-warning@-1 {{multiple unsequenced modifications to 'a'}}
154
155 ((a++, false) || (a++, false)); // no-warning PR39779
156 ((a++, true) && (a++, true)); // no-warning PR39779
157
158 int i,j;
159 (i = g1(), false) || (j = g2(i)); // no-warning PR22197
160 (i = g1(), true) && (j = g2(i)); // no-warning PR22197
161
162 (a++, false) || (a++, false) || (a++, false) || (a++, false); // no-warning
163 (a++, true) || (a++, true) || (a++, true) || (a++, true); // no-warning
164 a = ((a++, false) || (a++, false) || (a++, false) || (a++, false)); // no-warning
165 a = ((a++, true) && (a++, true) && (a++, true) && (a++, true)); // no-warning
166 a = ((a++, false) || (a++, false) || (a++, false) || a++); // cxx11-warning {{multiple unsequenced modifications to 'a'}}
167 a = ((a++, true) && (a++, true) && (a++, true) && a++); // cxx11-warning {{multiple unsequenced modifications to 'a'}}
168 a = ((a++, false) || (a++, false) || (a++, false) || (a + a, false)); // no-warning
169 a = ((a++, true) && (a++, true) && (a++, true) && (a + a, true)); // no-warning
170
171 a = (false && a++); // no-warning
172 a = (true && a++); // cxx11-warning {{multiple unsequenced modifications to 'a'}}
173 a = (true && ++a); // no-warning
174 a = (true || a++); // no-warning
175 a = (false || a++); // cxx11-warning {{multiple unsequenced modifications to 'a'}}
176 a = (false || ++a); // no-warning
177
178 (a++) | (a++); // cxx11-warning {{multiple unsequenced modifications to 'a'}}
179 // cxx17-warning@-1 {{multiple unsequenced modifications to 'a'}}
180 (a++) & (a++); // cxx11-warning {{multiple unsequenced modifications to 'a'}}
181 // cxx17-warning@-1 {{multiple unsequenced modifications to 'a'}}
182 (a++) ^ (a++); // cxx11-warning {{multiple unsequenced modifications to 'a'}}
183 // cxx17-warning@-1 {{multiple unsequenced modifications to 'a'}}
184
185 (__builtin_classify_type(++a) ? 1 : 0) + ++a; // ok
186 (__builtin_constant_p(++a) ? 1 : 0) + ++a; // ok
187 (__builtin_object_size(&(++a, a), 0) ? 1 : 0) + ++a; // ok
188 (__builtin_expect(++a, 0) ? 1 : 0) + ++a; // cxx11-warning {{multiple unsequenced modifications to 'a'}}
189 // cxx17-warning@-1 {{multiple unsequenced modifications to 'a'}}
190
191
192 int *p = xs;
193 a = *(a++, p); // no-warning
194 p[(long long unsigned)(p = 0)]; // cxx11-warning {{unsequenced modification and access to 'p'}}
195 (i++, xs)[i++]; // cxx11-warning {{multiple unsequenced modifications to 'i'}}
196 (++i, xs)[++i]; // cxx11-warning {{multiple unsequenced modifications to 'i'}}
197 (i, xs)[++i + ++i]; // cxx11-warning {{multiple unsequenced modifications to 'i'}}
198 // cxx17-warning@-1 {{multiple unsequenced modifications to 'i'}}
199 p++[p == xs]; // cxx11-warning {{unsequenced modification and access to 'p'}}
200 ++p[p++ == xs]; // cxx11-warning {{unsequenced modification and access to 'p'}}
201
202 struct S { int x; } s, *ps = &s;
203 int (S::*PtrMem);
204 (PtrMem = &S::x ,s).*(PtrMem); // cxx11-warning {{unsequenced modification and access to 'PtrMem'}}
205 (PtrMem = &S::x ,s).*(PtrMem = &S::x); // cxx11-warning {{multiple unsequenced modifications to 'PtrMem'}}
206 (PtrMem = &S::x ,ps)->*(PtrMem); // cxx11-warning {{unsequenced modification and access to 'PtrMem'}}
207 (PtrMem = &S::x ,ps)->*(PtrMem = &S::x); // cxx11-warning {{multiple unsequenced modifications to 'PtrMem'}}
208 (PtrMem = nullptr) == (PtrMem = nullptr); // cxx11-warning {{multiple unsequenced modifications to 'PtrMem'}}
209 // cxx17-warning@-1 {{multiple unsequenced modifications to 'PtrMem'}}
210 (PtrMem = nullptr) == PtrMem; // cxx11-warning {{unsequenced modification and access to 'PtrMem'}}
211 // cxx17-warning@-1 {{unsequenced modification and access to 'PtrMem'}}
212
213 i++ << i++; // cxx11-warning {{multiple unsequenced modifications to 'i'}}
214 ++i << ++i; // cxx11-warning {{multiple unsequenced modifications to 'i'}}
215 i++ << i; // cxx11-warning {{unsequenced modification and access to 'i'}}
216 i << i++; // cxx11-warning {{unsequenced modification and access to 'i'}}
217 i++ >> i++; // cxx11-warning {{multiple unsequenced modifications to 'i'}}
218 ++i >> ++i; // cxx11-warning {{multiple unsequenced modifications to 'i'}}
219 i++ >> i; // cxx11-warning {{unsequenced modification and access to 'i'}}
220 i >> i++; // cxx11-warning {{unsequenced modification and access to 'i'}}
221 (i++ << i) + i; // cxx11-warning {{unsequenced modification and access to 'i'}}
222 // cxx17-warning@-1 {{unsequenced modification and access to 'i'}}
223 (i++ << i) << i++; // cxx11-warning {{unsequenced modification and access to 'i'}}
224
225 ++i = i++; // cxx11-warning {{multiple unsequenced modifications to 'i'}}
226 i = i+= 1; // no-warning
227 i = i++ + ++i; // cxx11-warning {{multiple unsequenced modifications to 'i'}}
228 // cxx17-warning@-1 {{multiple unsequenced modifications to 'i'}}
229 ++i += ++i; // cxx11-warning {{multiple unsequenced modifications to 'i'}}
230 ++i += i++; // cxx11-warning {{multiple unsequenced modifications to 'i'}}
231 (i++, i) += ++i; // cxx11-warning {{multiple unsequenced modifications to 'i'}}
232 (i++, i) += i++; // cxx11-warning {{multiple unsequenced modifications to 'i'}}
233 i += i+= 1; // 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 i >>= ++i; // cxx11-warning {{unsequenced modification and access to 'i'}}
254
255 p[i++] = i; // cxx11-warning {{unsequenced modification and access to 'i'}}
256 p[i++] = (i = 42); // cxx11-warning {{multiple unsequenced modifications to 'i'}}
257 p++[i++] = (i = p ? i++ : i++); // cxx11-warning {{unsequenced modification and access to 'p'}}
258 // cxx11-warning@-1 {{multiple unsequenced modifications to 'i'}}
259 }
260
261 namespace members {
262
263 struct S1 {
264 unsigned bf1 : 2;
265 unsigned bf2 : 2;
266 unsigned a;
267 unsigned b;
268 static unsigned x;
269 void member_f(S1 &s);
270 };
271
member_f(S1 & s)272 void S1::member_f(S1 &s) {
273 ++a + ++a; // cxx11-warning {{multiple unsequenced modifications to 'a'}}
274 // cxx17-warning@-1 {{multiple unsequenced modifications to 'a'}}
275 a + ++a; // cxx11-warning {{unsequenced modification and access to 'a'}}
276 // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
277 ++a + ++b; // no-warning
278 a + ++b; // no-warning
279
280 // TODO: Warn here.
281 ++s.a + ++s.a; // no-warning TODO {{multiple unsequenced modifications to}}
282 s.a + ++s.a; // no-warning TODO {{unsequenced modification and access to}}
283 ++s.a + ++s.b; // no-warning
284 s.a + ++s.b; // no-warning
285
286 ++a + ++s.a; // no-warning
287 a + ++s.a; // no-warning
288 ++a + ++s.b; // no-warning
289 a + ++s.b; // no-warning
290
291 // TODO Warn here for bit-fields in the same memory location.
292 ++bf1 + ++bf1; // cxx11-warning {{multiple unsequenced modifications to 'bf1'}}
293 // cxx17-warning@-1 {{multiple unsequenced modifications to 'bf1'}}
294 bf1 + ++bf1; // cxx11-warning {{unsequenced modification and access to 'bf1'}}
295 // cxx17-warning@-1 {{unsequenced modification and access to 'bf1'}}
296 ++bf1 + ++bf2; // no-warning TODO {{multiple unsequenced modifications to}}
297 bf1 + ++bf2; // no-warning TODO {{unsequenced modification and access to}}
298
299 // TODO Warn here for bit-fields in the same memory location.
300 ++s.bf1 + ++s.bf1; // no-warning TODO {{multiple unsequenced modifications to}}
301 s.bf1 + ++s.bf1; // no-warning TODO {{unsequenced modification and access to}}
302 ++s.bf1 + ++s.bf2; // no-warning TODO {{multiple unsequenced modifications to}}
303 s.bf1 + ++s.bf2; // no-warning TODO {{unsequenced modification and access to}}
304
305 ++bf1 + ++s.bf1; // no-warning
306 bf1 + ++s.bf1; // no-warning
307 ++bf1 + ++s.bf2; // no-warning
308 bf1 + ++s.bf2; // no-warning
309
310 struct Der : S1 {};
311 Der d;
312 Der &d_ref = d;
313 S1 &s1_ref = d_ref;
314
315 ++s1_ref.a + ++d_ref.a; // no-warning TODO {{multiple unsequenced modifications to member 'a' of 'd'}}
316 ++s1_ref.a + d_ref.a; // no-warning TODO {{unsequenced modification and access to member 'a' of 'd'}}
317 ++s1_ref.a + ++d_ref.b; // no-warning
318 ++s1_ref.a + d_ref.b; // no-warning
319
320 ++x + ++x; // cxx11-warning {{multiple unsequenced modifications to 'x'}}
321 // cxx17-warning@-1 {{multiple unsequenced modifications to 'x'}}
322 ++x + x; // cxx11-warning {{unsequenced modification and access to 'x'}}
323 // cxx17-warning@-1 {{unsequenced modification and access to 'x'}}
324 ++s.x + x; // no-warning TODO {{unsequenced modification and access to static member 'x' of 'S1'}}
325 ++this->x + x; // cxx11-warning {{unsequenced modification and access to 'x'}}
326 // cxx17-warning@-1 {{unsequenced modification and access to 'x'}}
327 ++d_ref.x + ++S1::x; // no-warning TODO {{unsequenced modification and access to static member 'x' of 'S1'}}
328 }
329
330 struct S2 {
331 union { unsigned x, y; };
332 void f2();
333 };
334
f2()335 void S2::f2() {
336 ++x + ++x; // no-warning TODO {{multiple unsequenced modifications to}}
337 x + ++x; // no-warning TODO {{unsequenced modification and access to}}
338 ++x + ++y; // no-warning
339 x + ++y; // no-warning
340 }
341
f2(S2 & s)342 void f2(S2 &s) {
343 ++s.x + ++s.x; // no-warning TODO {{multiple unsequenced modifications to}}
344 s.x + ++s.x; // no-warning TODO {{unsequenced modification and access to}}
345 ++s.x + ++s.y; // no-warning
346 s.x + ++s.y; // no-warning
347 }
348
349 struct S3 {
350 union {
351 union {
352 unsigned x;
353 };
354 };
355 unsigned y;
356 void f3();
357 };
358
f3()359 void S3::f3() {
360 ++x + ++x; // no-warning TODO {{multiple unsequenced modifications to}}
361 x + ++x; // no-warning TODO {{unsequenced modification and access to}}
362 ++x + ++y; // no-warning
363 x + ++y; // no-warning
364 }
365
f3(S3 & s)366 void f3(S3 &s) {
367 ++s.x + ++s.x; // no-warning TODO {{multiple unsequenced modifications to}}
368 s.x + ++s.x; // no-warning TODO {{unsequenced modification and access to}}
369 ++s.x + ++s.y; // no-warning
370 s.x + ++s.y; // no-warning
371 }
372
373 struct S4 : S3 {
374 unsigned y;
375 void f4();
376 };
377
f4()378 void S4::f4() {
379 ++x + ++x; // no-warning TODO {{multiple unsequenced modifications to}}
380 x + ++x; // no-warning TODO {{unsequenced modification and access to}}
381 ++x + ++y; // no-warning
382 x + ++y; // no-warning
383 ++S3::y + ++y; // no-warning
384 S3::y + ++y; // no-warning
385 }
386
f4(S4 & s)387 void f4(S4 &s) {
388 ++s.x + ++s.x; // no-warning TODO {{multiple unsequenced modifications to}}
389 s.x + ++s.x; // no-warning TODO {{unsequenced modification and access to}}
390 ++s.x + ++s.y; // no-warning
391 s.x + ++s.y; // no-warning
392 ++s.S3::y + ++s.y; // no-warning
393 s.S3::y + ++s.y; // no-warning
394 }
395
396 static union {
397 unsigned Ux;
398 unsigned Uy;
399 };
400
f5()401 void f5() {
402 ++Ux + ++Ux; // no-warning TODO {{multiple unsequenced modifications to}}
403 Ux + ++Ux; // no-warning TODO {{unsequenced modification and access to}}
404 ++Ux + ++Uy; // no-warning
405 Ux + ++Uy; // no-warning
406 }
407
f6()408 void f6() {
409 struct S { unsigned x, y; } s;
410 ++s.x + ++s.x; // no-warning TODO {{multiple unsequenced modifications to}}
411 s.x + ++s.x; // no-warning TODO {{unsequenced modification and access to}}
412 ++s.x + ++s.y; // no-warning
413 s.x + ++s.y; // no-warning
414
415 struct { unsigned x, y; } t;
416 ++t.x + ++t.x; // no-warning TODO {{multiple unsequenced modifications to}}
417 t.x + ++t.x; // no-warning TODO {{unsequenced modification and access to}}
418 ++t.x + ++t.y; // no-warning
419 t.x + ++t.y; // no-warning
420 }
421
422 } // namespace members
423
424 namespace references {
reference_f()425 void reference_f() {
426 // TODO: Check that we can see through references.
427 // For now this is completely unhandled.
428 int a;
429 int xs[10];
430 int &b = a;
431 int &c = b;
432 int &ra1 = c;
433 int &ra2 = b;
434 int other;
435
436 ++ra1 + ++ra2; // no-warning TODO {{multiple unsequenced modifications to}}
437 ra1 + ++ra2; // no-warning TODO {{unsequenced modification and access to}}
438 ++ra1 + ++other; // no-warning
439 ra1 + ++other; // no-warning
440
441 // Make sure we handle reference cycles.
442 int &ref_cycle = ref_cycle;
443 ++ref_cycle + ++ref_cycle; // cxx11-warning {{multiple unsequenced modifications to 'ref_cycle'}}
444 // cxx17-warning@-1 {{multiple unsequenced modifications to 'ref_cycle'}}
445 ref_cycle + ++ref_cycle; // cxx11-warning {{unsequenced modification and access to 'ref_cycle'}}
446 // cxx17-warning@-1 {{unsequenced modification and access to 'ref_cycle'}}
447 }
448 } // namespace references
449
450 namespace std {
451 using size_t = decltype(sizeof(0));
452 template<typename> struct tuple_size;
453 template<size_t, typename> struct tuple_element { using type = int; };
454 }
455 namespace bindings {
456
457 struct A { int x, y; };
458 typedef int B[2];
459 struct C { template<int> int get(); };
460 struct D : A {};
461
462 } // namespace bindings
463 template<> struct std::tuple_size<bindings::C> { enum { value = 2 }; };
464 namespace bindings {
testa()465 void testa() {
466 A a;
467 {
468 auto [x, y] = a;
469 ++x + ++x; // cxx11-warning {{multiple unsequenced modifications to 'x'}}
470 // cxx17-warning@-1 {{multiple unsequenced modifications to 'x'}}
471 ++x + x; // cxx11-warning {{unsequenced modification and access to 'x'}}
472 // cxx17-warning@-1 {{unsequenced modification and access to 'x'}}
473 ++x + ++y; // no-warning
474 ++x + y; // no-warning
475 ++x + ++a.x; // no-warning
476 ++x + a.x; // no-warning
477 }
478 {
479 auto &[x, y] = a;
480 ++x + ++x; // cxx11-warning {{multiple unsequenced modifications to 'x'}}
481 // cxx17-warning@-1 {{multiple unsequenced modifications to 'x'}}
482 ++x + x; // cxx11-warning {{unsequenced modification and access to 'x'}}
483 // cxx17-warning@-1 {{unsequenced modification and access to 'x'}}
484 ++x + ++y; // no-warning
485 ++x + y; // no-warning
486 ++x + ++a.x; // no-warning TODO
487 ++x + a.x; // no-warning TODO
488 }
489 }
testb()490 void testb() {
491 B b;
492 {
493 auto [x, y] = b;
494 ++x + ++x; // cxx11-warning {{multiple unsequenced modifications to 'x'}}
495 // cxx17-warning@-1 {{multiple unsequenced modifications to 'x'}}
496 ++x + x; // cxx11-warning {{unsequenced modification and access to 'x'}}
497 // cxx17-warning@-1 {{unsequenced modification and access to 'x'}}
498 ++x + ++y; // no-warning
499 ++x + y; // no-warning
500 ++x + ++b[0]; // no-warning
501 ++x + b[0]; // no-warning
502 }
503 {
504 auto &[x, y] = b;
505 ++x + ++x; // cxx11-warning {{multiple unsequenced modifications to 'x'}}
506 // cxx17-warning@-1 {{multiple unsequenced modifications to 'x'}}
507 ++x + x; // cxx11-warning {{unsequenced modification and access to 'x'}}
508 // cxx17-warning@-1 {{unsequenced modification and access to 'x'}}
509 ++x + ++y; // no-warning
510 ++x + y; // no-warning
511 ++x + ++b[0]; // no-warning TODO
512 ++x + b[0]; // no-warning TODO
513 }
514 }
testc()515 void testc() {
516 C c;
517 {
518 auto [x, y] = c;
519 ++x + ++x; // cxx11-warning {{multiple unsequenced modifications to 'x'}}
520 // cxx17-warning@-1 {{multiple unsequenced modifications to 'x'}}
521 ++x + x; // cxx11-warning {{unsequenced modification and access to 'x'}}
522 // cxx17-warning@-1 {{unsequenced modification and access to 'x'}}
523 ++x + ++y; // no-warning
524 ++x + y; // no-warning
525 }
526 {
527 auto &[x, y] = c;
528 ++x + ++x; // cxx11-warning {{multiple unsequenced modifications to 'x'}}
529 // cxx17-warning@-1 {{multiple unsequenced modifications to 'x'}}
530 ++x + x; // cxx11-warning {{unsequenced modification and access to 'x'}}
531 // cxx17-warning@-1 {{unsequenced modification and access to 'x'}}
532 ++x + ++y; // no-warning
533 ++x + y; // no-warning
534 }
535 }
testd()536 void testd() {
537 D d;
538 {
539 auto [x, y] = d;
540 ++x + ++x; // cxx11-warning {{multiple unsequenced modifications to 'x'}}
541 // cxx17-warning@-1 {{multiple unsequenced modifications to 'x'}}
542 ++x + x; // cxx11-warning {{unsequenced modification and access to 'x'}}
543 // cxx17-warning@-1 {{unsequenced modification and access to 'x'}}
544 ++x + ++y; // no-warning
545 ++x + y; // no-warning
546 ++x + ++d.x; // no-warning
547 ++x + d.x; // no-warning
548 }
549 {
550 auto &[x, y] = d;
551 ++x + ++x; // cxx11-warning {{multiple unsequenced modifications to 'x'}}
552 // cxx17-warning@-1 {{multiple unsequenced modifications to 'x'}}
553 ++x + x; // cxx11-warning {{unsequenced modification and access to 'x'}}
554 // cxx17-warning@-1 {{unsequenced modification and access to 'x'}}
555 ++x + ++y; // no-warning
556 ++x + y; // no-warning
557 ++x + ++d.x; // no-warning TODO
558 ++x + d.x; // no-warning TODO
559 }
560 }
561 } // namespace bindings
562
563 namespace templates {
564
565 template <typename T>
566 struct Bar {
gettemplates::Bar567 T get() { return 0; }
568 };
569
570 template <typename X>
571 struct Foo {
572 int Run();
573 Bar<int> bar;
574 };
575
576 enum E {e1, e2};
577 bool operator&&(E, E);
578
579 void foo(int, int);
580
581 template <typename X>
Run()582 int Foo<X>::Run() {
583 char num = 0;
584
585 // Before instantiation, Clang may consider the builtin operator here as
586 // unresolved function calls, and treat the arguments as unordered when
587 // the builtin operator evaluatation is well-ordered. Waiting until
588 // instantiation to check these expressions will prevent false positives.
589 if ((num = bar.get()) < 5 && num < 10) { }
590 if ((num = bar.get()) < 5 || num < 10) { }
591 if (static_cast<E>((num = bar.get()) < 5) || static_cast<E>(num < 10)) { }
592
593 if (static_cast<E>((num = bar.get()) < 5) && static_cast<E>(num < 10)) { }
594 // cxx11-warning@-1 {{unsequenced modification and access to 'num'}}
595 // cxx17-warning@-2 {{unsequenced modification and access to 'num'}}
596
597 foo(num++, num++);
598 // cxx11-warning@-1 {{multiple unsequenced modifications to 'num'}}
599 // cxx17-warning@-2 {{multiple unsequenced modifications to 'num'}}
600 return 1;
601 }
602
603 int x = Foo<int>().Run();
604 // cxx11-note@-1 {{in instantiation of member function 'templates::Foo<int>::Run'}}
605 // cxx17-note@-2 {{in instantiation of member function 'templates::Foo<int>::Run'}}
606
607
608 template <typename T>
Run2()609 int Run2() {
610 T t = static_cast<T>(0);
611 return (t = static_cast<T>(1)) && t;
612 // cxx11-warning@-1 {{unsequenced modification and access to 't'}}
613 // cxx17-warning@-2 {{unsequenced modification and access to 't'}}
614 }
615
616 int y = Run2<bool>();
617 int z = Run2<E>();
618 // cxx11-note@-1{{in instantiation of function template specialization 'templates::Run2<templates::E>' requested here}}
619 // cxx17-note@-2{{in instantiation of function template specialization 'templates::Run2<templates::E>' requested here}}
620
621 template <typename T> int var = sizeof(T);
test_var()622 void test_var() {
623 var<int>++ + var<int>++; // cxx11-warning {{multiple unsequenced modifications to 'var<int>'}}
624 // cxx17-warning@-1 {{multiple unsequenced modifications to 'var<int>'}}
625 var<int>++ + var<int>; // cxx11-warning {{unsequenced modification and access to 'var<int>'}}
626 // cxx17-warning@-1 {{unsequenced modification and access to 'var<int>'}}
627 int &r = var<int>;
628 r++ + var<int>++; // no-warning TODO {{multiple unsequenced modifications to 'var<int>'}}
629 r++ + var<long>++; // no-warning
630 }
631
632 } // namespace templates
633