diff options
Diffstat (limited to 'gcc/testsuite/gcc.dg/Wattributes-8.c')
| -rw-r--r-- | gcc/testsuite/gcc.dg/Wattributes-8.c | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/gcc/testsuite/gcc.dg/Wattributes-8.c b/gcc/testsuite/gcc.dg/Wattributes-8.c new file mode 100644 index 00000000000..a4b4c00c08f --- /dev/null +++ b/gcc/testsuite/gcc.dg/Wattributes-8.c @@ -0,0 +1,38 @@ +/* PR middle-end/84108 - incorrect -Wattributes warning for packed/aligned + conflict on struct members + { dg-do compile } + { dg-options "-Wall -Wattributes" } */ + +#define ATTR(list) __attribute__ (list) +#define ASSERT(e) _Static_assert (e, #e) + +/* GCC is inconsistent in how it treats attribute aligned between + variable and member declarations. Attribute aligned alone is + sufficient to reduce a variable's alignment requirement but + the attribute must be paired with packed to have the same + effect on a member. Worse, declaring a variable both aligned + and packed emits a warning. */ + +/* Avoid exercising this since emitting a warning for these given + the requirement for members seems like a misfeature: + int a ATTR ((packed, aligned (2))); // -Wattributes + int b ATTR ((aligned (2), packed)); // -Wattributes + ASSERT (_Alignof (a) == 2); + ASSERT (_Alignof (b) == 2); */ + +int c ATTR ((aligned (2))); // okay (reduces alignment) +ASSERT (_Alignof (c) == 2); + +struct { + int a ATTR ((packed, aligned (2))); /* { dg-bogus "\\\[-Wattributes" } */ + int b ATTR ((aligned (2), packed)); /* { dg-bogus "\\\[-Wattributes" } */ + + /* Avoid exercising this since the attribute has no effect yet + there is no warning. + int c ATTR ((aligned (2))); // missing warning? */ +} s; + +ASSERT (_Alignof (s.a) == 2); +ASSERT (_Alignof (s.b) == 2); + +/* ASSERT (_Alignof (s.c) == 4); */ |