clang/test/C/C99/n736.c

   1 // RUN: %clang_cc1 -verify %s
   2
   3 /* WG14 N736: yes
   4  * preprocessor arithmetic done in intmax_t/uintmax_t
   5  */
   6
   7 // There is not a standard requirement that this relationships holds. If these
   8 // asserts fail, it means we have another test scenario to consider.
   9 _Static_assert(__INTMAX_MAX__ == __LONG_LONG_MAX__,
  10                "intmax_t is not the same width as long long?");
  11 _Static_assert((-__INTMAX_MAX__ - 1) == (-__LONG_LONG_MAX__ - 1LL),
  12                "intmax_t is not the same width as long long?");
  13 _Static_assert(__UINTMAX_MAX__ == (__LONG_LONG_MAX__ * 2ULL + 1ULL),
  14                "uintmax_t is not the same width as unsigned long long?");
  15
  16 // Test that arithmetic on the largest positive signed intmax_t works.
  17 #if 9223372036854775807LL + 0LL != 9223372036854775807LL
  18 #error "uh oh"
  19 #endif
  20
  21 // Same for negative.
  22 #if -9223372036854775807LL - 1LL + 0LL != -9223372036854775807LL - 1LL
  23 #error "uh oh"
  24 #endif
  25
  26 // Then test the same for unsigned
  27 #if 18446744073709551615ULL + 0ULL != 18446744073709551615ULL
  28 #error "uh oh"
  29 #endif
  30
  31 // Test that unsigned overflow causes silent wraparound.
  32 #if 18446744073709551615ULL + 1ULL != 0 // Silently wraps to 0.
  33 #error "uh oh"
  34 #endif
  35
  36 #if 0ULL - 1ULL != 18446744073709551615ULL // Silently wraps to 0xFFFF'FFFF'FFFF'FFFF.
  37 #error "uh oh"
  38 #endif
  39
  40 // Now test that signed arithmetic that pushes us over a limit is properly
  41 // diagnosed.
  42 #if 9223372036854775807LL + 1LL // expected-warning {{integer overflow in preprocessor expression}}
  43 #endif
  44
  45 #if -9223372036854775807LL - 2LL // expected-warning {{integer overflow in preprocessor expression}}
  46 #endif
  47