https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78809
--- Comment #16 from Wilco <wdijkstr at arm dot com> ---
(In reply to Qing Zhao from comment #15)
> (In reply to Wilco from comment 14)
> > The only reason we have to do a character by character comparison is
> > because we
> > cannot read beyond the end of a string. However when we know the size or
> > alignment we can safely process a string one word at a time.
>
> is it possible that “NULL_terminator” is in the middle of the string even
> though we
> know the size or alignment? for example:
>
> const char s[8] = “abcd\0abc”; // null byte in the middle of the string
> int f2(void) { return __builtin_strcmp(s, "abc") != 0; }
> int f3(void) { return __builtin_strcmp(s, “abc”); }
>
> can either of the above f2 or f3 been optimized to memcmp? seems not.
You never get that to the null byte as the memcmp only compares strlen("abc"+1)
characters. However do you mean an input string which is shorter than the
constant string? That's fine as this will compare not-equal in the memcmp.
