On Sat, 2009-06-20 at 17:01 +0200, Richard Guenther wrote:
> On Sat, Jun 20, 2009 at 4:54 PM, Jeff Law<[email protected]> wrote:
> >
> > Imagine a loop like this
> >
> > EXECUTE_IF_SET_IN_BITMAP (something, 0, i, bi)
> > {
> > bitmap_clear_bit (something, i)
> > [ ... whatever code we want to process i, ... ]
> > }
> >
> > This code is unsafe.
[snip]
> It is known (but maybe not appropriately documented) that deleting
> bits in the bitmap you iterate over is not safe. If it would be me I would
> see if I could make it safe though.
FYI, that's what I did with the sparseset implementation, so:
EXECUTE_IF_SET_IN_SPARSESET (something, i)
{
sparseset_clear_bit (something, i);
[ ... whatever code we want to process i, ... ]
}
is safe. In fact, we use it for one of the special cases in
sparseset_and() and sparseset_and_compl().
Peter
