https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61773
--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
Proper testcase (string init was missing):
char *stpcpy (char*, const char *);
char *foo (void)
{
char *p = __builtin_calloc (64, 1);
char *q = __builtin_calloc (64, 1);
__builtin_strcat (q, "abcde");
__builtin_strcat (p, "ab");
p[1] = 'a';
__builtin_strcat (p, q);
return q;
}
this isn't optimized either, only when p[0] = 'a'; is there the last
strcat will be optimized with known strlen of p. Hmm, a p[1] = '\0'
isn't optimized either.
Unfortunately strlen isn't very verbose in its -details dump.
