https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109141
Bug ID: 109141
Summary: failure to diagnose -Wuse-after-free early
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: rguenth at gcc dot gnu.org
Target Milestone: ---
gcc.dg/Wuse-after-free-2.c contains
int warn_cond_loop (char *p)
{
char *q = p;
/* -fno-tree-loop-distribute-patterns ensures this does not get converted
into rawmemchr (making q and p unrelated). Also, -fno-ivopts is required
for some targets, to not lose track of the pointer. */
while (*q)
++q;
free (p); // { dg-message "call to 'free'" }
return *q; // { dg-warning "pointer 'q' used after 'free'" }
}
which only is diagnosed in the late access warning pass. If you enable
-Wuse-after-free in the early passes it isn't diagnosed even though the
IL isn't very different. This looks like an issue in handling PHIs
in pointer query?
