------- Comment #6 from pinskia at gcc dot gnu dot org 2006-10-25 17:18 ------- (In reply to comment #5) > Yeah, I know, but why gcc generate good code if we add that printf to test1.c > (test2.c) ? It's still wchar * -> char * still aliasing violation.
Yes but there is a barrier which cause optimizations not to happen. > > or if we replace: > __SN(&str, 1); with > str = (CHAR_T *) (((char *) str) + 1); > > it generate good code too. it's still aliasing violation? No, that is legal as you are not accessing str (wchar_t*) as a "char*" any longer but as a "wchar_t*". You access str as a "wchar_t*" and then cast that value to a "char*" and then add one and then cast back to "wchar_t*" which causes the above code to be valid and defined. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29592