Compiling the code below (with -O2 -Wall -std=c99, gcc 4.4.3) gives the warning
apa.c: In function 'f':
cc1: warning: dereferencing pointer '({anonymous})' does break strict-aliasing
rules
apa.c:9: note: initialized from here
which is both unhelpful and dubious - is the code really doing anything wrong
here?
static int g(const void *p) {
int x;
__builtin_memcpy(&x, p, sizeof x);
return x;
}
struct s { char d[5]; };
int f(struct s ss) {
int t = 0;
for (int i = 0; i < 2; i++)
t += g(ss.d);
return t;
}
--
Summary: strict-aliasing warning from innocent code
Product: gcc
Version: 4.4.3
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: mattiase at acm dot org
GCC build triplet: i686-pc-linux-gnu
GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43421
