https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65178
Manuel López-Ibáñez <manu at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |diagnostic
Status|UNCONFIRMED |NEW
Last reconfirmed| |2015-02-23
CC| |manu at gcc dot gnu.org
Blocks| |24639
Ever confirmed|0 |1
--- Comment #1 from Manuel López-Ibáñez <manu at gcc dot gnu.org> ---
A minimized testcase:
void *bar(int);
char *
foo (void)
{
char *c = "bla";
char *buf;
for (int a = 1;; a = 0)
{
for (char *s = c; *s; ++s)
{
}
if (!a) break;
buf = (char *) bar (1);
}
return buf;
}
It fails in GCC 5.0 with -O1, -O2 and -O3. I think we have several reports
about this: GCC simply does not understand that the loop body is executed at
least once, thus there should be no (default) entry edge for the PHI node of
buf.
I think it is a missed optimization also: If buf were initialized, the initial
value could be dropped.
