On 28.09.2022 16:27, Roger Pau Monné wrote: > On Wed, Sep 28, 2022 at 02:12:30PM +0200, Jan Beulich wrote: >> While for some of the functions there's locking involved, the acquiring >> and releasing of a lock doesn't alter program state when comparing >> "before" and "after" the function invocations. Furthermore without >> (further) locking by callers, return values are stale anyway by the time >> they can be evaluated. Hence both CSE and DCE are okay to occur for >> invocations of these functions. >> >> Signed-off-by: Jan Beulich <jbeul...@suse.com> >> --- >> RFC for the (imo) ambiguous wording in documentation. > > What happens if the contents of the rangeset is modified outside of > the scope of the function. Ie: would for example: > > while ( !rangeset_is_empty(...) ); > > Become an infinite loop then, without taking into account that the > rangeset can be externally modified? > > It's not clear to me whether the elimination of repeated calls take > into account that the observed variable can be externally modified?
Hmm, right, this actually matches the feof() counter-example that the gcc doc has. So I guess I need to withdraw the patch and we will need to live with these functions not being possible to eliminate even in cases where it would be okay (and helpful). Jan
