http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50712
--- Comment #2 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-10-13 10:06:04 UTC --- Reduced testcase (suspicious because of address-taking of a valist): typedef __builtin_va_list __va_list; typedef __va_list __gnuc_va_list; typedef __gnuc_va_list va_list; struct MSVCRT__iobuf { }; typedef struct MSVCRT__iobuf MSVCRT_FILE; typedef union _printf_arg { } printf_arg; MSVCRT_FILE MSVCRT__iob[20]; int pf_print_a (va_list *); int __attribute__((__cdecl__)) MSVCRT_vfprintf_s(MSVCRT_FILE* file, const char *format, va_list valist) { if(!((file != ((void *)0)) || (MSVCRT__invalid_parameter(((void *)0), ((void *)0), ((void *)0), 0, 0),0))) return -1; return pf_printf_a(&valist); } int __attribute__((__cdecl__)) MSVCRT_vprintf_s(const char *format, va_list valist) { return MSVCRT_vfprintf_s((MSVCRT__iob+1),format,valist); } int __attribute__((__cdecl__)) MSVCRT_fprintf_s(MSVCRT_FILE* file, const char *format, ...) { va_list valist; va_start (valist, format); return MSVCRT_vfprintf_s(file, format, valist); }