Take:
struct a
{
union
{
int a;
int b;
};
union
{
int c;
int d;
};
};
int f(struct a *c)
{
int d = c->a;
c->c = 1;
return c->a + d;
}
--- CUT ---
There should only be one load from c->a but currently there is two
--
Summary: Union in structs are not well optimized
Product: gcc
Version: 4.4.0
Status: UNCONFIRMED
Keywords: missed-optimization
Severity: normal
Priority: P3
Component: tree-optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: pinskia at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38207
