File: constexpr-duffs-device.cpp

package info (click to toggle)
llvm-toolchain-14 1%3A14.0.6-12
  • links: PTS, VCS
  • area: main
  • in suites: bookworm
  • size: 1,496,180 kB
  • sloc: cpp: 5,593,972; ansic: 986,872; asm: 585,869; python: 184,223; objc: 72,530; lisp: 31,119; f90: 27,793; javascript: 9,780; pascal: 9,762; sh: 9,482; perl: 7,468; ml: 5,432; awk: 3,523; makefile: 2,538; xml: 953; cs: 573; fortran: 567
file content (32 lines) | stat: -rw-r--r-- 942 bytes parent folder | download | duplicates (28) 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
 
// 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");