1 // RUN: %clang_cc1 %s -triple x86_64-linux-gnu -std=c++2a -fsyntax-only -verify -pedantic -Wno-vla-extension
2 // RUN: %clang_cc1 %s -triple x86_64-linux-gnu -std=gnu++2a -fsyntax-only -verify -pedantic -Wno-vla-extension -DGNUMODE
3 // RUN: %clang_cc1 %s -triple x86_64-linux-gnu -std=c++2a -fsyntax-only -verify -pedantic -Wno-vla-extension -fno-signed-char
4 // RUN: %clang_cc1 %s -triple x86_64-linux-gnu -std=c++2a -fsyntax-only -verify -pedantic -Wno-vla-extension -fno-wchar -DNO_PREDEFINED_WCHAR_T
5 // RUN: %clang_cc1 %s -triple armebv7-unknown-linux -std=c++2a -fsyntax-only -verify -pedantic -Wno-vla-extension
6 // RUN: %clang_cc1 %s -triple armebv7-unknown-linux -std=gnu++2a -fsyntax-only -verify -pedantic -Wno-vla-extension -DGNUMODE
7 // RUN: %clang_cc1 %s -triple armebv7-unknown-linux -std=c++2a -fsyntax-only -verify -pedantic -Wno-vla-extension -fno-signed-char
8 // RUN: %clang_cc1 %s -triple armebv7-unknown-linux -std=c++2a -fsyntax-only -verify -pedantic -Wno-vla-extension -fno-wchar -DNO_PREDEFINED_WCHAR_T
9 
10 # 9 "/usr/include/string.h" 1 3 4
11 extern "C" {
12   typedef decltype(sizeof(int)) size_t;
13 
14   extern size_t strlen(const char *p);
15 
16   extern int strcmp(const char *s1, const char *s2);
17   extern int strncmp(const char *s1, const char *s2, size_t n);
18   extern int memcmp(const void *s1, const void *s2, size_t n);
19 
20 #ifdef GNUMODE
21   extern int bcmp(const void *s1, const void *s2, size_t n);
22 #endif
23 
24   extern char *strchr(const char *s, int c);
25   extern void *memchr(const void *s, int c, size_t n);
26 
27   extern void *memcpy(void *d, const void *s, size_t n);
28   extern void *memmove(void *d, const void *s, size_t n);
29 }
30 # 25 "SemaCXX/constexpr-string.cpp" 2
31 
32 # 27 "/usr/include/wchar.h" 1 3 4
33 extern "C" {
34 #if NO_PREDEFINED_WCHAR_T
35   typedef decltype(L'0') wchar_t;
36 #endif
37   extern size_t wcslen(const wchar_t *p);
38 
39   extern int wcscmp(const wchar_t *s1, const wchar_t *s2);
40   extern int wcsncmp(const wchar_t *s1, const wchar_t *s2, size_t n);
41   extern int wmemcmp(const wchar_t *s1, const wchar_t *s2, size_t n);
42 
43   extern wchar_t *wcschr(const wchar_t *s, wchar_t c);
44   extern wchar_t *wmemchr(const wchar_t *s, wchar_t c, size_t n);
45 
46   extern wchar_t *wmemcpy(wchar_t *d, const wchar_t *s, size_t n);
47   extern wchar_t *wmemmove(wchar_t *d, const wchar_t *s, size_t n);
48 }
49 
50 # 51 "SemaCXX/constexpr-string.cpp" 2
51 namespace Strlen {
52   constexpr int n = __builtin_strlen("hello"); // ok
53   static_assert(n == 5);
54   constexpr int wn = __builtin_wcslen(L"hello"); // ok
55   static_assert(wn == 5);
56   constexpr int m = strlen("hello"); // expected-error {{constant expression}} expected-note {{non-constexpr function 'strlen' cannot be used in a constant expression}}
57   constexpr int wm = wcslen(L"hello"); // expected-error {{constant expression}} expected-note {{non-constexpr function 'wcslen' cannot be used in a constant expression}}
58 
59   // Make sure we can evaluate a call to strlen.
60   int arr[3]; // expected-note 2{{here}}
61   int k = arr[strlen("hello")]; // expected-warning {{array index 5}}
62   int wk = arr[wcslen(L"hello")]; // expected-warning {{array index 5}}
63 }
64 
65 namespace StrcmpEtc {
66   constexpr char kFoobar[6] = {'f','o','o','b','a','r'};
67   constexpr char kFoobazfoobar[12] = {'f','o','o','b','a','z','f','o','o','b','a','r'};
68 
69   static_assert(__builtin_strcmp("abab", "abab") == 0);
70   static_assert(__builtin_strcmp("abab", "abba") == -1);
71   static_assert(__builtin_strcmp("abab", "abaa") == 1);
72   static_assert(__builtin_strcmp("ababa", "abab") == 1);
73   static_assert(__builtin_strcmp("abab", "ababa") == -1);
74   static_assert(__builtin_strcmp("a\203", "a") == 1);
75   static_assert(__builtin_strcmp("a\203", "a\003") == 1);
76   static_assert(__builtin_strcmp("abab\0banana", "abab") == 0);
77   static_assert(__builtin_strcmp("abab", "abab\0banana") == 0);
78   static_assert(__builtin_strcmp("abab\0banana", "abab\0canada") == 0);
79   static_assert(__builtin_strcmp(0, "abab") == 0); // expected-error {{not an integral constant}} expected-note {{dereferenced null}}
80   static_assert(__builtin_strcmp("abab", 0) == 0); // expected-error {{not an integral constant}} expected-note {{dereferenced null}}
81 
82   static_assert(__builtin_strcmp(kFoobar, kFoobazfoobar) == -1); // FIXME: Should we reject this?
83   static_assert(__builtin_strcmp(kFoobar, kFoobazfoobar + 6) == 0); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}}
84 
85   static_assert(__builtin_strncmp("abaa", "abba", 5) == -1);
86   static_assert(__builtin_strncmp("abaa", "abba", 4) == -1);
87   static_assert(__builtin_strncmp("abaa", "abba", 3) == -1);
88   static_assert(__builtin_strncmp("abaa", "abba", 2) == 0);
89   static_assert(__builtin_strncmp("abaa", "abba", 1) == 0);
90   static_assert(__builtin_strncmp("abaa", "abba", 0) == 0);
91   static_assert(__builtin_strncmp(0, 0, 0) == 0);
92   static_assert(__builtin_strncmp("abab\0banana", "abab\0canada", 100) == 0);
93 
94   static_assert(__builtin_strncmp(kFoobar, kFoobazfoobar, 6) == -1);
95   static_assert(__builtin_strncmp(kFoobar, kFoobazfoobar, 7) == -1); // FIXME: Should we reject this?
96   static_assert(__builtin_strncmp(kFoobar, kFoobazfoobar + 6, 6) == 0);
97   static_assert(__builtin_strncmp(kFoobar, kFoobazfoobar + 6, 7) == 0); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}}
98 
99   static_assert(__builtin_memcmp("abaa", "abba", 3) == -1);
100   static_assert(__builtin_memcmp("abaa", "abba", 2) == 0);
101   static_assert(__builtin_memcmp("a\203", "a", 2) == 1);
102   static_assert(__builtin_memcmp("a\203", "a\003", 2) == 1);
103   static_assert(__builtin_memcmp(0, 0, 0) == 0);
104   static_assert(__builtin_memcmp("abab\0banana", "abab\0banana", 100) == 0); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}}
105   static_assert(__builtin_memcmp("abab\0banana", "abab\0canada", 100) == -1); // FIXME: Should we reject this?
106   static_assert(__builtin_memcmp("abab\0banana", "abab\0canada", 7) == -1);
107   static_assert(__builtin_memcmp("abab\0banana", "abab\0canada", 6) == -1);
108   static_assert(__builtin_memcmp("abab\0banana", "abab\0canada", 5) == 0);
109 
110   static_assert(__builtin_memcmp(u8"abaa", u8"abba", 3) == -1);
111   static_assert(__builtin_memcmp(u8"abaa", u8"abba", 2) == 0);
112   static_assert(__builtin_memcmp(u8"a\203", u8"a", 2) == 1);
113   static_assert(__builtin_memcmp(u8"a\203", u8"a\003", 2) == 1);
114   static_assert(__builtin_memcmp(0, 0, 0) == 0);
115   static_assert(__builtin_memcmp(u8"abab\0banana", u8"abab\0banana", 100) == 0); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}}
116   static_assert(__builtin_memcmp(u8"abab\0banana", u8"abab\0canada", 100) == -1); // FIXME: Should we reject this?
117   static_assert(__builtin_memcmp(u8"abab\0banana", u8"abab\0canada", 7) == -1);
118   static_assert(__builtin_memcmp(u8"abab\0banana", u8"abab\0canada", 6) == -1);
119   static_assert(__builtin_memcmp(u8"abab\0banana", u8"abab\0canada", 5) == 0);
120 
121   static_assert(__builtin_memcmp(u8"\u1234", "\xE1\x88\xB4", 4) == 0);
122   static_assert(__builtin_memcmp(u8"\u1234", "\xE1\x88\xB3", 4) == 1);
123 
124   static_assert(__builtin_bcmp("abaa", "abba", 3) != 0);
125   static_assert(__builtin_bcmp("abaa", "abba", 2) == 0);
126   static_assert(__builtin_bcmp("a\203", "a", 2) != 0);
127   static_assert(__builtin_bcmp("a\203", "a\003", 2) != 0);
128   static_assert(__builtin_bcmp(0, 0, 0) == 0);
129   static_assert(__builtin_bcmp("abab\0banana", "abab\0banana", 100) == 0); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}}
130   static_assert(__builtin_bcmp("abab\0banana", "abab\0canada", 100) != 0); // FIXME: Should we reject this?
131   static_assert(__builtin_bcmp("abab\0banana", "abab\0canada", 7) != 0);
132   static_assert(__builtin_bcmp("abab\0banana", "abab\0canada", 6) != 0);
133   static_assert(__builtin_bcmp("abab\0banana", "abab\0canada", 5) == 0);
134 
135   extern struct Incomplete incomplete;
136   static_assert(__builtin_memcmp(&incomplete, "", 0u) == 0);
137   static_assert(__builtin_memcmp("", &incomplete, 0u) == 0);
138   static_assert(__builtin_memcmp(&incomplete, "", 1u) == 42); // expected-error {{not an integral constant}} expected-note {{not supported}}
139   static_assert(__builtin_memcmp("", &incomplete, 1u) == 42); // expected-error {{not an integral constant}} expected-note {{not supported}}
140 
141   static_assert(__builtin_bcmp(&incomplete, "", 0u) == 0);
142   static_assert(__builtin_bcmp("", &incomplete, 0u) == 0);
143   static_assert(__builtin_bcmp(&incomplete, "", 1u) == 42); // expected-error {{not an integral constant}} expected-note {{not supported}}
144   static_assert(__builtin_bcmp("", &incomplete, 1u) == 42); // expected-error {{not an integral constant}} expected-note {{not supported}}
145 
146   constexpr unsigned char ku00fe00[] = {0x00, 0xfe, 0x00};
147   constexpr unsigned char ku00feff[] = {0x00, 0xfe, 0xff};
148   constexpr signed char ks00fe00[] = {0, -2, 0};
149   constexpr signed char ks00feff[] = {0, -2, -1};
150   static_assert(__builtin_memcmp(ku00feff, ks00fe00, 2) == 0);
151   static_assert(__builtin_memcmp(ku00feff, ks00fe00, 99) == 1);
152   static_assert(__builtin_memcmp(ku00fe00, ks00feff, 99) == -1);
153   static_assert(__builtin_memcmp(ks00feff, ku00fe00, 2) == 0);
154   static_assert(__builtin_memcmp(ks00feff, ku00fe00, 99) == 1);
155   static_assert(__builtin_memcmp(ks00fe00, ku00feff, 99) == -1);
156   static_assert(__builtin_memcmp(ks00fe00, ks00feff, 2) == 0);
157   static_assert(__builtin_memcmp(ks00feff, ks00fe00, 99) == 1);
158   static_assert(__builtin_memcmp(ks00fe00, ks00feff, 99) == -1);
159 
160   static_assert(__builtin_bcmp(ku00feff, ks00fe00, 2) == 0);
161   static_assert(__builtin_bcmp(ku00feff, ks00fe00, 99) != 0);
162   static_assert(__builtin_bcmp(ku00fe00, ks00feff, 99) != 0);
163   static_assert(__builtin_bcmp(ks00feff, ku00fe00, 2) == 0);
164   static_assert(__builtin_bcmp(ks00feff, ku00fe00, 99) != 0);
165   static_assert(__builtin_bcmp(ks00fe00, ku00feff, 99) != 0);
166   static_assert(__builtin_bcmp(ks00fe00, ks00feff, 2) == 0);
167   static_assert(__builtin_bcmp(ks00feff, ks00fe00, 99) != 0);
168   static_assert(__builtin_bcmp(ks00fe00, ks00feff, 99) != 0);
169 
170   struct Bool3Tuple { bool bb[3]; };
171   constexpr Bool3Tuple kb000100 = {{false, true, false}};
172   static_assert(sizeof(bool) != 1u || __builtin_memcmp(ks00fe00, kb000100.bb, 1) == 0); // expected-error {{constant}} expected-note {{not supported}}
173   static_assert(sizeof(bool) != 1u || __builtin_memcmp(ks00fe00, kb000100.bb, 2) == 1); // expected-error {{constant}} expected-note {{not supported}}
174 
175   static_assert(sizeof(bool) != 1u || __builtin_bcmp(ks00fe00, kb000100.bb, 1) == 0); // expected-error {{constant}} expected-note {{not supported}}
176   static_assert(sizeof(bool) != 1u || __builtin_bcmp(ks00fe00, kb000100.bb, 2) != 0); // expected-error {{constant}} expected-note {{not supported}}
177 
178   constexpr long ksl[] = {0, -1};
179   constexpr unsigned int kui[] = {0, 0u - 1};
180   constexpr unsigned long long kull[] = {0, 0ull - 1};
kuSizeofLong(void)181   constexpr const auto *kuSizeofLong(void) {
182     if constexpr(sizeof(long) == sizeof(int)) {
183       return kui;
184     } else if constexpr(sizeof(long) == sizeof(long long)) {
185       return kull;
186     } else {
187       return nullptr;
188     }
189   }
190   static_assert(__builtin_memcmp(ksl, kuSizeofLong(), sizeof(long) - 1) == 0); // expected-error {{constant}} expected-note {{not supported}}
191   static_assert(__builtin_memcmp(ksl, kuSizeofLong(), sizeof(long) + 0) == 0); // expected-error {{constant}} expected-note {{not supported}}
192   static_assert(__builtin_memcmp(ksl, kuSizeofLong(), sizeof(long) + 1) == 0); // expected-error {{constant}} expected-note {{not supported}}
193   static_assert(__builtin_memcmp(ksl, kuSizeofLong(), 2*sizeof(long) - 1) == 0); // expected-error {{constant}} expected-note {{not supported}}
194   static_assert(__builtin_memcmp(ksl, kuSizeofLong(), 2*sizeof(long) + 0) == 0); // expected-error {{constant}} expected-note {{not supported}}
195   static_assert(__builtin_memcmp(ksl, kuSizeofLong(), 2*sizeof(long) + 1) == 42); // expected-error {{constant}} expected-note {{not supported}}
196   static_assert(__builtin_memcmp(ksl + 1, kuSizeofLong() + 1, sizeof(long) - 1) == 0); // expected-error {{constant}} expected-note {{not supported}}
197   static_assert(__builtin_memcmp(ksl + 1, kuSizeofLong() + 1, sizeof(long) + 0) == 0); // expected-error {{constant}} expected-note {{not supported}}
198   static_assert(__builtin_memcmp(ksl + 1, kuSizeofLong() + 1, sizeof(long) + 1) == 42); // expected-error {{constant}} expected-note {{not supported}}
199 
200   static_assert(__builtin_bcmp(ksl, kuSizeofLong(), sizeof(long) - 1) == 0); // expected-error {{constant}} expected-note {{not supported}}
201   static_assert(__builtin_bcmp(ksl, kuSizeofLong(), sizeof(long) + 0) == 0); // expected-error {{constant}} expected-note {{not supported}}
202   static_assert(__builtin_bcmp(ksl, kuSizeofLong(), sizeof(long) + 1) == 0); // expected-error {{constant}} expected-note {{not supported}}
203   static_assert(__builtin_bcmp(ksl, kuSizeofLong(), 2*sizeof(long) - 1) == 0); // expected-error {{constant}} expected-note {{not supported}}
204   static_assert(__builtin_bcmp(ksl, kuSizeofLong(), 2*sizeof(long) + 0) == 0); // expected-error {{constant}} expected-note {{not supported}}
205   static_assert(__builtin_bcmp(ksl, kuSizeofLong(), 2*sizeof(long) + 1) == 42); // expected-error {{constant}} expected-note {{not supported}}
206   static_assert(__builtin_bcmp(ksl + 1, kuSizeofLong() + 1, sizeof(long) - 1) == 0); // expected-error {{constant}} expected-note {{not supported}}
207   static_assert(__builtin_bcmp(ksl + 1, kuSizeofLong() + 1, sizeof(long) + 0) == 0); // expected-error {{constant}} expected-note {{not supported}}
208   static_assert(__builtin_bcmp(ksl + 1, kuSizeofLong() + 1, sizeof(long) + 1) == 42); // expected-error {{constant}} expected-note {{not supported}}
209 
210   constexpr int a = strcmp("hello", "world"); // expected-error {{constant expression}} expected-note {{non-constexpr function 'strcmp' cannot be used in a constant expression}}
211   constexpr int b = strncmp("hello", "world", 3); // expected-error {{constant expression}} expected-note {{non-constexpr function 'strncmp' cannot be used in a constant expression}}
212   constexpr int c = memcmp("hello", "world", 3); // expected-error {{constant expression}} expected-note {{non-constexpr function 'memcmp' cannot be used in a constant expression}}
213 
214 #ifdef GNUMODE
215   constexpr int d = bcmp("hello", "world", 3); // expected-error {{constant expression}} expected-note {{non-constexpr function 'bcmp' cannot be used in a constant expression}}
216 #endif
217 }
218 
219 namespace MultibyteElementTests {
220 inline namespace Util {
221 #define STR2(X) #X
222 #define STR(X) STR2(X)
223 constexpr const char ByteOrderString[] = STR(__BYTE_ORDER__);
224 #undef STR
225 #undef STR2
226 constexpr bool LittleEndian{*ByteOrderString == '1'};
227 
228 constexpr size_t GoodFoldArraySize = 42, BadFoldArraySize = 43;
229 struct NotBadFoldResult {};
230 template <size_t> struct FoldResult;
231 template <> struct FoldResult<GoodFoldArraySize> : NotBadFoldResult {};
232 template <typename T, size_t N>
233 FoldResult<N> *foldResultImpl(T (*ptrToConstantSizeArray)[N]);
234 struct NotFolded : NotBadFoldResult {};
235 NotFolded *foldResultImpl(bool anyPtr);
236 template <auto Value> struct MetaValue;
237 template <typename Callable, size_t N, auto ExpectedFoldResult>
foldResult(const Callable &,MetaValue<N> *,MetaValue<ExpectedFoldResult> *)238 auto foldResult(const Callable &, MetaValue<N> *,
239                 MetaValue<ExpectedFoldResult> *) {
240   int (*maybeVLAPtr)[Callable{}(N) == ExpectedFoldResult
241                          ? GoodFoldArraySize
242                          : BadFoldArraySize] = 0;
243   return foldResultImpl(maybeVLAPtr);
244 }
245 template <typename FoldResultKind, typename Callable, typename NWrap,
246           typename ExpectedWrap>
checkFoldResult(const Callable & c,NWrap * n,ExpectedWrap * e)247 constexpr bool checkFoldResult(const Callable &c, NWrap *n, ExpectedWrap *e) {
248   decltype(static_cast<FoldResultKind *>(foldResult(c, n, e))) *chk{};
249   return true;
250 }
withN()251 template <size_t N> constexpr MetaValue<N> *withN() { return nullptr; }
withExpected()252 template <auto Expected> constexpr MetaValue<Expected> *withExpected() {
253   return nullptr;
254 }
255 } // namespace Util
256 } // namespace MultibyteElementTests
257 
258 namespace MultibyteElementTests::Memcmp {
259 #ifdef __SIZEOF_INT128__
260 constexpr __int128 i128_ff_8_00_8 = -(__int128)1 - -1ull;
261 constexpr __int128 i128_00_16 = 0;
262 static_assert(checkFoldResult<NotBadFoldResult>(
__anon8420feec0602(size_t n) 263     [](size_t n) constexpr {
264       return __builtin_memcmp(&i128_ff_8_00_8, &i128_00_16, n);
265     },
266     withN<1u>(), withExpected<LittleEndian ? 0 : 1>()));
267 #endif
268 
269 constexpr const signed char ByteOrderStringReduced[] = {
270     ByteOrderString[0] - '0', ByteOrderString[1] - '0',
271     ByteOrderString[2] - '0', ByteOrderString[3] - '0',
272 };
273 constexpr signed int i04030201 = 0x04030201;
274 constexpr unsigned int u04030201 = 0x04030201u;
275 static_assert(checkFoldResult<NotBadFoldResult>(
__anon8420feec0702(size_t n) 276     [](size_t n) constexpr {
277       return __builtin_memcmp(ByteOrderStringReduced, &i04030201, n);
278     },
279     withN<sizeof(int)>(), withExpected<0>()));
280 static_assert(checkFoldResult<NotBadFoldResult>(
__anon8420feec0802(size_t n) 281     [](size_t n) constexpr {
282       return __builtin_memcmp(&u04030201, ByteOrderStringReduced, n);
283     },
284     withN<sizeof(int)>(), withExpected<0>()));
285 
286 constexpr unsigned int ui0000FEFF = 0x0000feffU;
287 constexpr unsigned short usFEFF = 0xfeffU;
288 static_assert(checkFoldResult<NotBadFoldResult>(
__anon8420feec0902(size_t n) 289     [](size_t n) constexpr {
290       return __builtin_memcmp(&ui0000FEFF, &usFEFF, n);
291     },
292     withN<1u>(), withExpected<LittleEndian ? 0 : -1>()));
293 
294 constexpr unsigned int ui08038700 = 0x08038700u;
295 constexpr unsigned int ui08048600 = 0x08048600u;
296 static_assert(checkFoldResult<NotBadFoldResult>(
__anon8420feec0a02(size_t n) 297     [](size_t n) constexpr {
298       return __builtin_memcmp(&ui08038700, &ui08048600, n);
299     },
300     withN<sizeof(int)>(), withExpected<LittleEndian ? 1 : -1>()));
301 }
302 
303 namespace WcscmpEtc {
304   constexpr wchar_t kFoobar[6] = {L'f',L'o',L'o',L'b',L'a',L'r'};
305   constexpr wchar_t kFoobazfoobar[12] = {L'f',L'o',L'o',L'b',L'a',L'z',L'f',L'o',L'o',L'b',L'a',L'r'};
306 
307   static_assert(__builtin_wcscmp(L"abab", L"abab") == 0);
308   static_assert(__builtin_wcscmp(L"abab", L"abba") == -1);
309   static_assert(__builtin_wcscmp(L"abab", L"abaa") == 1);
310   static_assert(__builtin_wcscmp(L"ababa", L"abab") == 1);
311   static_assert(__builtin_wcscmp(L"abab", L"ababa") == -1);
312   static_assert(__builtin_wcscmp(L"abab\0banana", L"abab") == 0);
313   static_assert(__builtin_wcscmp(L"abab", L"abab\0banana") == 0);
314   static_assert(__builtin_wcscmp(L"abab\0banana", L"abab\0canada") == 0);
315 #if __WCHAR_WIDTH__ == 32
316   static_assert(__builtin_wcscmp(L"a\x83838383", L"a") == (wchar_t)-1U >> 31);
317 #endif
318   static_assert(__builtin_wcscmp(0, L"abab") == 0); // expected-error {{not an integral constant}} expected-note {{dereferenced null}}
319   static_assert(__builtin_wcscmp(L"abab", 0) == 0); // expected-error {{not an integral constant}} expected-note {{dereferenced null}}
320 
321   static_assert(__builtin_wcscmp(kFoobar, kFoobazfoobar) == -1); // FIXME: Should we reject this?
322   static_assert(__builtin_wcscmp(kFoobar, kFoobazfoobar + 6) == 0); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}}
323 
324   static_assert(__builtin_wcsncmp(L"abaa", L"abba", 5) == -1);
325   static_assert(__builtin_wcsncmp(L"abaa", L"abba", 4) == -1);
326   static_assert(__builtin_wcsncmp(L"abaa", L"abba", 3) == -1);
327   static_assert(__builtin_wcsncmp(L"abaa", L"abba", 2) == 0);
328   static_assert(__builtin_wcsncmp(L"abaa", L"abba", 1) == 0);
329   static_assert(__builtin_wcsncmp(L"abaa", L"abba", 0) == 0);
330   static_assert(__builtin_wcsncmp(0, 0, 0) == 0);
331   static_assert(__builtin_wcsncmp(L"abab\0banana", L"abab\0canada", 100) == 0);
332 #if __WCHAR_WIDTH__ == 32
333   static_assert(__builtin_wcsncmp(L"a\x83838383", L"aa", 2) ==
334                 (wchar_t)-1U >> 31);
335 #endif
336 
337   static_assert(__builtin_wcsncmp(kFoobar, kFoobazfoobar, 6) == -1);
338   static_assert(__builtin_wcsncmp(kFoobar, kFoobazfoobar, 7) == -1); // FIXME: Should we reject this?
339   static_assert(__builtin_wcsncmp(kFoobar, kFoobazfoobar + 6, 6) == 0);
340   static_assert(__builtin_wcsncmp(kFoobar, kFoobazfoobar + 6, 7) == 0); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}}
341 
342   static_assert(__builtin_wmemcmp(L"abaa", L"abba", 3) == -1);
343   static_assert(__builtin_wmemcmp(L"abaa", L"abba", 2) == 0);
344   static_assert(__builtin_wmemcmp(0, 0, 0) == 0);
345 #if __WCHAR_WIDTH__ == 32
346   static_assert(__builtin_wmemcmp(L"a\x83838383", L"aa", 2) ==
347                 (wchar_t)-1U >> 31);
348 #endif
349   static_assert(__builtin_wmemcmp(L"abab\0banana", L"abab\0banana", 100) == 0); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}}
350   static_assert(__builtin_wmemcmp(L"abab\0banana", L"abab\0canada", 100) == -1); // FIXME: Should we reject this?
351   static_assert(__builtin_wmemcmp(L"abab\0banana", L"abab\0canada", 7) == -1);
352   static_assert(__builtin_wmemcmp(L"abab\0banana", L"abab\0canada", 6) == -1);
353   static_assert(__builtin_wmemcmp(L"abab\0banana", L"abab\0canada", 5) == 0);
354 
355   constexpr int a = wcscmp(L"hello", L"world"); // expected-error {{constant expression}} expected-note {{non-constexpr function 'wcscmp' cannot be used in a constant expression}}
356   constexpr int b = wcsncmp(L"hello", L"world", 3); // expected-error {{constant expression}} expected-note {{non-constexpr function 'wcsncmp' cannot be used in a constant expression}}
357   constexpr int c = wmemcmp(L"hello", L"world", 3); // expected-error {{constant expression}} expected-note {{non-constexpr function 'wmemcmp' cannot be used in a constant expression}}
358 }
359 
360 namespace StrchrEtc {
361   constexpr const char *kStr = "abca\xff\0d";
362   constexpr char kFoo[] = {'f', 'o', 'o'};
363   static_assert(__builtin_strchr(kStr, 'a') == kStr);
364   static_assert(__builtin_strchr(kStr, 'b') == kStr + 1);
365   static_assert(__builtin_strchr(kStr, 'c') == kStr + 2);
366   static_assert(__builtin_strchr(kStr, 'd') == nullptr);
367   static_assert(__builtin_strchr(kStr, 'e') == nullptr);
368   static_assert(__builtin_strchr(kStr, '\0') == kStr + 5);
369   static_assert(__builtin_strchr(kStr, 'a' + 256) == nullptr);
370   static_assert(__builtin_strchr(kStr, 'a' - 256) == nullptr);
371   static_assert(__builtin_strchr(kStr, '\xff') == kStr + 4);
372   static_assert(__builtin_strchr(kStr, '\xff' + 256) == nullptr);
373   static_assert(__builtin_strchr(kStr, '\xff' - 256) == nullptr);
374   static_assert(__builtin_strchr(kFoo, 'o') == kFoo + 1);
375   static_assert(__builtin_strchr(kFoo, 'x') == nullptr); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}}
376   static_assert(__builtin_strchr(nullptr, 'x') == nullptr); // expected-error {{not an integral constant}} expected-note {{dereferenced null}}
377 
378   static_assert(__builtin_memchr(kStr, 'a', 0) == nullptr);
379   static_assert(__builtin_memchr(kStr, 'a', 1) == kStr);
380   static_assert(__builtin_memchr(kStr, '\0', 5) == nullptr);
381   static_assert(__builtin_memchr(kStr, '\0', 6) == kStr + 5);
382   static_assert(__builtin_memchr(kStr, '\xff', 8) == kStr + 4);
383   static_assert(__builtin_memchr(kStr, '\xff' + 256, 8) == kStr + 4);
384   static_assert(__builtin_memchr(kStr, '\xff' - 256, 8) == kStr + 4);
385   static_assert(__builtin_memchr(kFoo, 'x', 3) == nullptr);
386   static_assert(__builtin_memchr(kFoo, 'x', 4) == nullptr); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}}
387   static_assert(__builtin_memchr(nullptr, 'x', 3) == nullptr); // expected-error {{not an integral constant}} expected-note {{dereferenced null}}
388   static_assert(__builtin_memchr(nullptr, 'x', 0) == nullptr); // FIXME: Should we reject this?
389 
390   constexpr const char8_t *kU8Str = u8"abca\xff\0d";
391   constexpr char8_t kU8Foo[] = {u8'f', u8'o', u8'o'};
392   static_assert(__builtin_memchr(kU8Str, u8'a', 0) == nullptr);
393   static_assert(__builtin_memchr(kU8Str, u8'a', 1) == kU8Str);
394   static_assert(__builtin_memchr(kU8Str, u8'\0', 5) == nullptr);
395   static_assert(__builtin_memchr(kU8Str, u8'\0', 6) == kU8Str + 5);
396   static_assert(__builtin_memchr(kU8Str, u8'\xff', 8) == kU8Str + 4);
397   static_assert(__builtin_memchr(kU8Str, u8'\xff' + 256, 8) == kU8Str + 4);
398   static_assert(__builtin_memchr(kU8Str, u8'\xff' - 256, 8) == kU8Str + 4);
399   static_assert(__builtin_memchr(kU8Foo, u8'x', 3) == nullptr);
400   static_assert(__builtin_memchr(kU8Foo, u8'x', 4) == nullptr); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}}
401   static_assert(__builtin_memchr(nullptr, u8'x', 3) == nullptr); // expected-error {{not an integral constant}} expected-note {{dereferenced null}}
402   static_assert(__builtin_memchr(nullptr, u8'x', 0) == nullptr); // FIXME: Should we reject this?
403 
404   extern struct Incomplete incomplete;
405   static_assert(__builtin_memchr(&incomplete, 0, 0u) == nullptr);
406   static_assert(__builtin_memchr(&incomplete, 0, 1u) == nullptr); // expected-error {{not an integral constant}} expected-note {{read of incomplete type 'struct Incomplete'}}
407 
408   const unsigned char &u1 = 0xf0;
409   auto &&i1 = (const signed char []){-128}; // expected-warning {{compound literals are a C99-specific feature}}
410   static_assert(__builtin_memchr(&u1, -(0x0f + 1), 1) == &u1);
411   static_assert(__builtin_memchr(i1, 0x80, 1) == i1);
412 
413   enum class E : unsigned char {};
414   struct EPair { E e, f; };
415   constexpr EPair ee{E{240}};
416   static_assert(__builtin_memchr(&ee.e, 240, 1) == &ee.e); // expected-error {{constant}} expected-note {{not supported}}
417 
418   constexpr bool kBool[] = {false, true, false};
419   constexpr const bool *const kBoolPastTheEndPtr = kBool + 3;
420   static_assert(sizeof(bool) != 1u || __builtin_memchr(kBoolPastTheEndPtr - 3, 1, 99) == kBool + 1); // expected-error {{constant}} expected-note {{not supported}}
421   static_assert(sizeof(bool) != 1u || __builtin_memchr(kBool + 1, 0, 99) == kBoolPastTheEndPtr - 1); // expected-error {{constant}} expected-note {{not supported}}
422   static_assert(sizeof(bool) != 1u || __builtin_memchr(kBoolPastTheEndPtr - 3, -1, 3) == nullptr); // expected-error {{constant}} expected-note {{not supported}}
423   static_assert(sizeof(bool) != 1u || __builtin_memchr(kBoolPastTheEndPtr, 0, 1) == nullptr); // expected-error {{constant}} expected-note {{not supported}}
424 
425   static_assert(__builtin_char_memchr(kStr, 'a', 0) == nullptr);
426   static_assert(__builtin_char_memchr(kStr, 'a', 1) == kStr);
427   static_assert(__builtin_char_memchr(kStr, '\0', 5) == nullptr);
428   static_assert(__builtin_char_memchr(kStr, '\0', 6) == kStr + 5);
429   static_assert(__builtin_char_memchr(kStr, '\xff', 8) == kStr + 4);
430   static_assert(__builtin_char_memchr(kStr, '\xff' + 256, 8) == kStr + 4);
431   static_assert(__builtin_char_memchr(kStr, '\xff' - 256, 8) == kStr + 4);
432   static_assert(__builtin_char_memchr(kFoo, 'x', 3) == nullptr);
433   static_assert(__builtin_char_memchr(kFoo, 'x', 4) == nullptr); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}}
434   static_assert(__builtin_char_memchr(nullptr, 'x', 3) == nullptr); // expected-error {{not an integral constant}} expected-note {{dereferenced null}}
435   static_assert(__builtin_char_memchr(nullptr, 'x', 0) == nullptr); // FIXME: Should we reject this?
436 
437   static_assert(*__builtin_char_memchr(kStr, '\xff', 8) == '\xff');
438   constexpr bool char_memchr_mutable() {
439     char buffer[] = "mutable";
440     *__builtin_char_memchr(buffer, 't', 8) = 'r';
441     *__builtin_char_memchr(buffer, 'm', 8) = 'd';
442     return __builtin_strcmp(buffer, "durable") == 0;
443   }
444   static_assert(char_memchr_mutable());
445 
446   constexpr bool a = !strchr("hello", 'h'); // expected-error {{constant expression}} expected-note {{non-constexpr function 'strchr' cannot be used in a constant expression}}
447   constexpr bool b = !memchr("hello", 'h', 3); // expected-error {{constant expression}} expected-note {{non-constexpr function 'memchr' cannot be used in a constant expression}}
448 }
449 
450 namespace MultibyteElementTests::Memchr {
451 constexpr unsigned int u04030201 = 0x04030201;
452 static_assert(checkFoldResult<NotBadFoldResult>(
453     [](size_t n) constexpr {
454       return __builtin_memchr(&u04030201, *ByteOrderString - '0', n);
455     },
456     withN<1u>(), withExpected<&u04030201>()));
457 
458 constexpr unsigned int uED = 0xEDU;
459 static_assert(checkFoldResult<NotBadFoldResult>(
460     [](size_t n) constexpr {
461       return __builtin_memchr(&uED, 0xED, n);
462     },
463     withN<1u>(), withExpected<LittleEndian ? &uED : nullptr>()));
464 }
465 
466 namespace WcschrEtc {
467   constexpr const wchar_t *kStr = L"abca\xffff\0dL";
468   constexpr wchar_t kFoo[] = {L'f', L'o', L'o'};
469   static_assert(__builtin_wcschr(kStr, L'a') == kStr);
470   static_assert(__builtin_wcschr(kStr, L'b') == kStr + 1);
471   static_assert(__builtin_wcschr(kStr, L'c') == kStr + 2);
472   static_assert(__builtin_wcschr(kStr, L'd') == nullptr);
473   static_assert(__builtin_wcschr(kStr, L'e') == nullptr);
474   static_assert(__builtin_wcschr(kStr, L'\0') == kStr + 5);
475   static_assert(__builtin_wcschr(kStr, L'a' + 256) == nullptr);
476   static_assert(__builtin_wcschr(kStr, L'a' - 256) == nullptr);
477   static_assert(__builtin_wcschr(kStr, L'\xffff') == kStr + 4);
478   static_assert(__builtin_wcschr(kFoo, L'o') == kFoo + 1);
479   static_assert(__builtin_wcschr(kFoo, L'x') == nullptr); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}}
480   static_assert(__builtin_wcschr(nullptr, L'x') == nullptr); // expected-error {{not an integral constant}} expected-note {{dereferenced null}}
481 
482   static_assert(__builtin_wmemchr(kStr, L'a', 0) == nullptr);
483   static_assert(__builtin_wmemchr(kStr, L'a', 1) == kStr);
484   static_assert(__builtin_wmemchr(kStr, L'\0', 5) == nullptr);
485   static_assert(__builtin_wmemchr(kStr, L'\0', 6) == kStr + 5);
486   static_assert(__builtin_wmemchr(kStr, L'\xffff', 8) == kStr + 4);
487   static_assert(__builtin_wmemchr(kFoo, L'x', 3) == nullptr);
488   static_assert(__builtin_wmemchr(kFoo, L'x', 4) == nullptr); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}}
489   static_assert(__builtin_wmemchr(nullptr, L'x', 3) == nullptr); // expected-error {{not an integral constant}} expected-note {{dereferenced null}}
490   static_assert(__builtin_wmemchr(nullptr, L'x', 0) == nullptr); // FIXME: Should we reject this?
491 
492   constexpr bool a = !wcschr(L"hello", L'h'); // expected-error {{constant expression}} expected-note {{non-constexpr function 'wcschr' cannot be used in a constant expression}}
493   constexpr bool b = !wmemchr(L"hello", L'h', 3); // expected-error {{constant expression}} expected-note {{non-constexpr function 'wmemchr' cannot be used in a constant expression}}
494 }
495 
496 namespace MemcpyEtc {
497   template<typename T>
498   constexpr T result(T (&arr)[4]) {
499     return arr[0] * 1000 + arr[1] * 100 + arr[2] * 10 + arr[3];
500   }
501 
502   constexpr int test_memcpy(int a, int b, int n) {
503     int arr[4] = {1, 2, 3, 4};
504     __builtin_memcpy(arr + a, arr + b, n);
505     // expected-note@-1 2{{overlapping memory regions}}
506     // expected-note@-2 {{size to copy (1) is not a multiple of size of element type 'int'}}
507     // expected-note@-3 {{source is not a contiguous array of at least 2 elements of type 'int'}}
508     // expected-note@-4 {{destination is not a contiguous array of at least 3 elements of type 'int'}}
509     return result(arr);
510   }
511   constexpr int test_memmove(int a, int b, int n) {
512     int arr[4] = {1, 2, 3, 4};
513     __builtin_memmove(arr + a, arr + b, n);
514     // expected-note@-1 {{size to copy (1) is not a multiple of size of element type 'int'}}
515     // expected-note@-2 {{source is not a contiguous array of at least 2 elements of type 'int'}}
516     // expected-note@-3 {{destination is not a contiguous array of at least 3 elements of type 'int'}}
517     return result(arr);
518   }
519   constexpr int test_wmemcpy(int a, int b, int n) {
520     wchar_t arr[4] = {1, 2, 3, 4};
521     __builtin_wmemcpy(arr + a, arr + b, n);
522     // expected-note@-1 2{{overlapping memory regions}}
523     // expected-note@-2 {{source is not a contiguous array of at least 2 elements of type 'wchar_t'}}
524     // expected-note@-3 {{destination is not a contiguous array of at least 3 elements of type 'wchar_t'}}
525     return result(arr);
526   }
527   constexpr int test_wmemmove(int a, int b, int n) {
528     wchar_t arr[4] = {1, 2, 3, 4};
529     __builtin_wmemmove(arr + a, arr + b, n);
530     // expected-note@-1 {{source is not a contiguous array of at least 2 elements of type 'wchar_t'}}
531     // expected-note@-2 {{destination is not a contiguous array of at least 3 elements of type 'wchar_t'}}
532     return result(arr);
533   }
534 
535   static_assert(test_memcpy(1, 2, 4) == 1334);
536   static_assert(test_memcpy(2, 1, 4) == 1224);
537   static_assert(test_memcpy(0, 1, 8) == 2334); // expected-error {{constant}} expected-note {{in call}}
538   static_assert(test_memcpy(1, 0, 8) == 1124); // expected-error {{constant}} expected-note {{in call}}
539   static_assert(test_memcpy(1, 2, 1) == 1334); // expected-error {{constant}} expected-note {{in call}}
540   static_assert(test_memcpy(0, 3, 4) == 4234);
541   static_assert(test_memcpy(0, 3, 8) == 4234); // expected-error {{constant}} expected-note {{in call}}
542   static_assert(test_memcpy(2, 0, 12) == 4234); // expected-error {{constant}} expected-note {{in call}}
543 
544   static_assert(test_memmove(1, 2, 4) == 1334);
545   static_assert(test_memmove(2, 1, 4) == 1224);
546   static_assert(test_memmove(0, 1, 8) == 2334);
547   static_assert(test_memmove(1, 0, 8) == 1124);
548   static_assert(test_memmove(1, 2, 1) == 1334); // expected-error {{constant}} expected-note {{in call}}
549   static_assert(test_memmove(0, 3, 4) == 4234);
550   static_assert(test_memmove(0, 3, 8) == 4234); // expected-error {{constant}} expected-note {{in call}}
551   static_assert(test_memmove(2, 0, 12) == 4234); // expected-error {{constant}} expected-note {{in call}}
552 
553   static_assert(test_wmemcpy(1, 2, 1) == 1334);
554   static_assert(test_wmemcpy(2, 1, 1) == 1224);
555   static_assert(test_wmemcpy(0, 1, 2) == 2334); // expected-error {{constant}} expected-note {{in call}}
556   static_assert(test_wmemcpy(1, 0, 2) == 1124); // expected-error {{constant}} expected-note {{in call}}
557   static_assert(test_wmemcpy(1, 2, 1) == 1334);
558   static_assert(test_wmemcpy(0, 3, 1) == 4234);
559   static_assert(test_wmemcpy(0, 3, 2) == 4234); // expected-error {{constant}} expected-note {{in call}}
560   static_assert(test_wmemcpy(2, 0, 3) == 4234); // expected-error {{constant}} expected-note {{in call}}
561 
562   static_assert(test_wmemmove(1, 2, 1) == 1334);
563   static_assert(test_wmemmove(2, 1, 1) == 1224);
564   static_assert(test_wmemmove(0, 1, 2) == 2334);
565   static_assert(test_wmemmove(1, 0, 2) == 1124);
566   static_assert(test_wmemmove(1, 2, 1) == 1334);
567   static_assert(test_wmemmove(0, 3, 1) == 4234);
568   static_assert(test_wmemmove(0, 3, 2) == 4234); // expected-error {{constant}} expected-note {{in call}}
569   static_assert(test_wmemmove(2, 0, 3) == 4234); // expected-error {{constant}} expected-note {{in call}}
570 
571 #define fold(x) (__builtin_constant_p(0) ? (x) : (x))
572 
573   wchar_t global;
574   constexpr wchar_t *null = 0;
575   static_assert(__builtin_memcpy(&global, null, sizeof(wchar_t))); // expected-error {{}} expected-note {{source of 'memcpy' is nullptr}}
576   static_assert(__builtin_memmove(&global, null, sizeof(wchar_t))); // expected-error {{}} expected-note {{source of 'memmove' is nullptr}}
577   static_assert(__builtin_wmemcpy(&global, null, sizeof(wchar_t))); // expected-error {{}} expected-note {{source of 'wmemcpy' is nullptr}}
578   static_assert(__builtin_wmemmove(&global, null, sizeof(wchar_t))); // expected-error {{}} expected-note {{source of 'wmemmove' is nullptr}}
579   static_assert(__builtin_memcpy(null, &global, sizeof(wchar_t))); // expected-error {{}} expected-note {{destination of 'memcpy' is nullptr}}
580   static_assert(__builtin_memmove(null, &global, sizeof(wchar_t))); // expected-error {{}} expected-note {{destination of 'memmove' is nullptr}}
581   static_assert(__builtin_wmemcpy(null, &global, sizeof(wchar_t))); // expected-error {{}} expected-note {{destination of 'wmemcpy' is nullptr}}
582   static_assert(__builtin_wmemmove(null, &global, sizeof(wchar_t))); // expected-error {{}} expected-note {{destination of 'wmemmove' is nullptr}}
583   static_assert(__builtin_memcpy(&global, fold((wchar_t*)123), sizeof(wchar_t))); // expected-error {{}} expected-note {{source of 'memcpy' is (void *)123}}
584   static_assert(__builtin_memcpy(fold(reinterpret_cast<wchar_t*>(123)), &global, sizeof(wchar_t))); // expected-error {{}} expected-note {{destination of 'memcpy' is (void *)123}}
585   constexpr struct Incomplete *null_incomplete = 0;
586   static_assert(__builtin_memcpy(null_incomplete, null_incomplete, sizeof(wchar_t))); // expected-error {{}} expected-note {{source of 'memcpy' is nullptr}}
587 
588   // Copying is permitted for any trivially-copyable type.
589   struct Trivial { char k; short s; constexpr bool ok() { return k == 3 && s == 4; } };
590   constexpr bool test_trivial() {
591     Trivial arr[3] = {{1, 2}, {3, 4}, {5, 6}};
592     __builtin_memcpy(arr, arr+1, sizeof(Trivial));
593     __builtin_memmove(arr+1, arr, 2 * sizeof(Trivial));
594     return arr[0].ok() && arr[1].ok() && arr[2].ok();
595   }
596   static_assert(test_trivial());
597 
598   // But not for a non-trivially-copyable type.
599   struct NonTrivial {
600     constexpr NonTrivial() : n(0) {}
601     constexpr NonTrivial(const NonTrivial &) : n(1) {}
602     int n;
603   };
604   constexpr bool test_nontrivial_memcpy() { // expected-error {{never produces a constant}}
605     NonTrivial arr[3] = {};
606     __builtin_memcpy(arr, arr + 1, sizeof(NonTrivial)); // expected-note 2{{non-trivially-copyable}}
607     return true;
608   }
609   static_assert(test_nontrivial_memcpy()); // expected-error {{constant}} expected-note {{in call}}
610   constexpr bool test_nontrivial_memmove() { // expected-error {{never produces a constant}}
611     NonTrivial arr[3] = {};
612     __builtin_memcpy(arr, arr + 1, sizeof(NonTrivial)); // expected-note 2{{non-trivially-copyable}}
613     return true;
614   }
615   static_assert(test_nontrivial_memmove()); // expected-error {{constant}} expected-note {{in call}}
616 
617   // Type puns via constant evaluated memcpy are not supported yet.
618   constexpr float type_pun(const unsigned &n) {
619     float f = 0.0f;
620     __builtin_memcpy(&f, &n, 4); // expected-note {{cannot constant evaluate 'memcpy' from object of type 'const unsigned int' to object of type 'float'}}
621     return f;
622   }
623   static_assert(type_pun(0x3f800000) == 1.0f); // expected-error {{constant}} expected-note {{in call}}
624 
625   // Make sure we're not confused by derived-to-base conversions.
626   struct Base { int a; };
627   struct Derived : Base { int b; };
628   constexpr int test_derived_to_base(int n) {
629     Derived arr[2] = {1, 2, 3, 4};
630     Base *p = &arr[0];
631     Base *q = &arr[1];
632     __builtin_memcpy(p, q, sizeof(Base) * n); // expected-note {{source is not a contiguous array of at least 2 elements of type 'MemcpyEtc::Base'}}
633     return arr[0].a * 1000 + arr[0].b * 100 + arr[1].a * 10 + arr[1].b;
634   }
635   static_assert(test_derived_to_base(0) == 1234);
636   static_assert(test_derived_to_base(1) == 3234);
637   // FIXME: We could consider making this work by stripping elements off both
638   // designators until we have a long enough matching size, if both designators
639   // point to the start of their respective final elements.
640   static_assert(test_derived_to_base(2) == 3434); // expected-error {{constant}} expected-note {{in call}}
641 
642   // Check that when address-of an array is passed to a tested function the
643   // array can be fully copied.
644   constexpr int test_address_of_const_array_type() {
645     int arr[4] = {1, 2, 3, 4};
646     __builtin_memmove(&arr, &arr, sizeof(arr));
647     return arr[0] * 1000 + arr[1] * 100 + arr[2] * 10 + arr[3];
648   }
649   static_assert(test_address_of_const_array_type() == 1234);
650 
651   // Check that an incomplete array is rejected.
652   constexpr int test_incomplete_array_type() { // expected-error {{never produces a constant}}
653     extern int arr[];
654     __builtin_memmove(arr, arr, 4 * sizeof(arr[0]));
655     // expected-note@-1 2{{'memmove' not supported: source is not a contiguous array of at least 4 elements of type 'int'}}
656     return arr[0] * 1000 + arr[1] * 100 + arr[2] * 10 + arr[3];
657   }
658   static_assert(test_incomplete_array_type() == 1234); // expected-error {{constant}} expected-note {{in call}}
659 
660   // Check that a pointer to an incomplete array is rejected.
661   constexpr int test_address_of_incomplete_array_type() { // expected-error {{never produces a constant}}
662     extern int arr[];
663     __builtin_memmove(&arr, &arr, 4 * sizeof(arr[0]));
664     // expected-note@-1 2{{cannot constant evaluate 'memmove' between objects of incomplete type 'int []'}}
665     return arr[0] * 1000 + arr[1] * 100 + arr[2] * 10 + arr[3];
666   }
667   static_assert(test_address_of_incomplete_array_type() == 1234); // expected-error {{constant}} expected-note {{in call}}
668 
669   // Check that a pointer to an incomplete struct is rejected.
670   constexpr bool test_address_of_incomplete_struct_type() { // expected-error {{never produces a constant}}
671     struct Incomplete;
672     extern Incomplete x, y;
673     __builtin_memcpy(&x, &x, 4);
674     // expected-note@-1 2{{cannot constant evaluate 'memcpy' between objects of incomplete type 'Incomplete'}}
675     return true;
676   }
677   static_assert(test_address_of_incomplete_struct_type()); // expected-error {{constant}} expected-note {{in call}}
678 }
679