llvm-project/clang/test/SemaCXX/constexpr-duffs-device.cpp

33 lines
942 B
C++

// RUN: %clang_cc1 -std=c++1y -verify %s
// expected-no-diagnostics
constexpr void copy(const char *from, unsigned long count, char *to) {
unsigned long n = (count + 7) / 8;
switch(count % 8) {
case 0: do { *to++ = *from++;
case 7: *to++ = *from++;
case 6: *to++ = *from++;
case 5: *to++ = *from++;
case 4: *to++ = *from++;
case 3: *to++ = *from++;
case 2: *to++ = *from++;
case 1: *to++ = *from++;
} while(--n > 0);
}
}
struct S {
char stuff[14];
constexpr S() : stuff{} {
copy("Hello, world!", 14, stuff);
}
};
constexpr bool streq(const char *a, const char *b) {
while (*a && *a == *b) ++a, ++b;
return *a == *b;
}
static_assert(streq(S().stuff, "Hello, world!"), "should be same");
static_assert(!streq(S().stuff, "Something else"), "should be different");