diff options
Diffstat (limited to 'm4/stdalign.m4')
| -rw-r--r-- | m4/stdalign.m4 | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/m4/stdalign.m4 b/m4/stdalign.m4 index 9752ba568..6659c9c3e 100644 --- a/m4/stdalign.m4 +++ b/m4/stdalign.m4 @@ -14,13 +14,27 @@ AC_DEFUN([gl_STDALIGN_H], [AC_COMPILE_IFELSE( [AC_LANG_PROGRAM( [[#include <stdalign.h> - int align_int = alignof (int) + _Alignof (double); + #include <stddef.h> + + /* Test that alignof yields a result consistent with offsetof. + This catches GCC bug 52023 + <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52023>. */ + #ifdef __cplusplus + template <class t> struct alignof_helper { char a; t b; }; + # define ao(type) offsetof (alignof_helper<type>, b) + #else + # define ao(type) offsetof (struct { char a; type b; }, b) + #endif + char test_double[ao (double) % _Alignof (double) == 0 ? 1 : -1]; + char test_long[ao (long int) % _Alignof (long int) == 0 ? 1 : -1]; + char test_alignof[alignof (double) == _Alignof (double) ? 1 : -1]; /* Test _Alignas only on platforms where gnulib can help. */ #if \ (__GNUC__ || __IBMC__ || __IBMCPP__ \ || 0x5110 <= __SUNPRO_C || 1300 <= _MSC_VER) int alignas (8) alignas_int = 1; + char test_alignas[_Alignof (alignas_int) == 8 ? 1 : -1]; #endif ]])], [gl_cv_header_working_stdalign_h=yes], |