[Bug tree-optimization/35200] [4.3 Regression] bogus aliasing warning

[rguenth at gcc dot gnu dot org]

------- Comment #7 from rguenth at gcc dot gnu dot org  2008-02-14 21:19 -------
ISO C even disallows type-punning with unions (which is in fact a GNU
extension):

union { int i; float f } u;
u.i = 1;
return u.f;

invokes undefined behavior in ISO C.  You have to use memcpy and two different
memory objects like

int i = 1;
float f;
memcpy (&f, &i, 4);
return f;

to be portable and ISO C conformant.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35200