------- Comment #23 from rguenth at gcc dot gnu dot org 2008-11-21 11:09
-------
We actually usually never ask for the alias set of an indirect reference, but
instead we seem to use the pointed-to type instead which doesn't inherit the
restrict handling. Otherwise we would miscompile even the trivial
int foo (int *__restrict p)
{
int *__restrict q;
int v;
q = p + 1;
q = q - 1;
v = *q;
*p = 1;
return v + *q;
}
extern void abort (void);
int main()
{
int i = 0;
if (foo (&i) != 1)
abort ();
return 0;
}
because q is not based on the restrict p and both pointers would get
distinct alias-sets which you can verify by calling get_alias_set on
the indirect-refs.
So one way to fix the issue in the vectorizer is to avoid calling
get_alias_set on the indirect-refs as well. Or to rip out all the
broken restrict handling from the compiler.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37742
