clang/test/SemaCXX/builtin-assume-aligned.cpp

   1 // RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 -triple x86_64-linux-gnu %s
   2
   3 int n;
   4 constexpr int *p = 0;
   5 // expected-error@+1 {{must be initialized by a constant expression}}
   6 constexpr int *k = (int *) __builtin_assume_aligned(p, 16, n = 5);
   7
   8 constexpr void *l = __builtin_assume_aligned(p, 16);
   9
  10 // expected-error@+2 {{must be initialized by a constant expression}}
  11 // expected-note@+1 {{cast from 'void *' is not allowed in a constant expression}}
  12 constexpr int *c = (int *) __builtin_assume_aligned(p, 16);
  13
  14 // expected-error@+2 {{must be initialized by a constant expression}}
  15 // expected-note@+1 {{alignment of the base pointee object (4 bytes) is less than the asserted 16 bytes}}
  16 constexpr void *m = __builtin_assume_aligned(&n, 16);
  17
  18 // expected-error@+2 {{must be initialized by a constant expression}}
  19 // expected-note@+1 {{offset of the aligned pointer from the base pointee object (-2 bytes) is not a multiple of the asserted 4 bytes}}
  20 constexpr void *q1 = __builtin_assume_aligned(&n, 4, 2);
  21 // expected-error@+2 {{must be initialized by a constant expression}}
  22 // expected-note@+1 {{offset of the aligned pointer from the base pointee object (2 bytes) is not a multiple of the asserted 4 bytes}}
  23 constexpr void *q2 = __builtin_assume_aligned(&n, 4, -2);
  24 constexpr void *q3 = __builtin_assume_aligned(&n, 4, 4);
  25 constexpr void *q4 = __builtin_assume_aligned(&n, 4, -4);
  26
  27 static char ar1[6];
  28 // expected-error@+2 {{must be initialized by a constant expression}}
  29 // expected-note@+1 {{alignment of the base pointee object (1 byte) is less than the asserted 16 bytes}}
  30 constexpr void *r1 = __builtin_assume_aligned(&ar1[2], 16);
  31
  32 static char ar2[6] __attribute__((aligned(32)));
  33 // expected-error@+2 {{must be initialized by a constant expression}}
  34 // expected-note@+1 {{offset of the aligned pointer from the base pointee object (2 bytes) is not a multiple of the asserted 16 bytes}}
  35 constexpr void *r2 = __builtin_assume_aligned(&ar2[2], 16);
  36 constexpr void *r3 = __builtin_assume_aligned(&ar2[2], 16, 2);
  37 // expected-error@+2 {{must be initialized by a constant expression}}
  38 // expected-note@+1 {{offset of the aligned pointer from the base pointee object (1 byte) is not a multiple of the asserted 16 bytes}}
  39 constexpr void *r4 = __builtin_assume_aligned(&ar2[2], 16, 1);
  40
  41 constexpr int* x = __builtin_constant_p((int*)0xFF) ? (int*)0xFF : (int*)0xFF;
  42 // expected-error@+2 {{must be initialized by a constant expression}}
  43 // expected-note@+1 {{value of the aligned pointer (255) is not a multiple of the asserted 32 bytes}}
  44 constexpr void *s1 = __builtin_assume_aligned(x, 32);
  45 // expected-error@+2 {{must be initialized by a constant expression}}
  46 // expected-note@+1 {{value of the aligned pointer (250) is not a multiple of the asserted 32 bytes}}
  47 constexpr void *s2 = __builtin_assume_aligned(x, 32, 5);
  48 constexpr void *s3 = __builtin_assume_aligned(x, 32, -1);
  49