Consider this code:
struct p {
short x, y;
};
struct s {
int i;
struct p p;
};
struct s f()
{
struct s s;
s.p = (struct p){};
s.i = (s.p.x || s.p.y);
return s;
}
When compiled with gcc -Wall -O -c, it reports:
t.c: In function 'f':
t.c:14: warning: 's.i' is used uninitialized in this function
That's not right. Furthermore, I think the generated assembly might be wrong
(this is with -O):
f:
movl $0, %eax
ret
The return value should be a full 64 bits (%rax), but only the bottom 32 are
initialized (unless this clears the high ones on x86_64 or the calling
convention says they are already -- I don't really know).
--
Summary: uninitialized structure member after assignment
Product: gcc
Version: 4.0.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: dylan at dylex dot net
GCC build triplet: x86_64-pc-linux-gnu
GCC host triplet: x86_64-pc-linux-gnu
GCC target triplet: x86_64-pc-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24931
