On 2013-07-29 08:02:49 -0400, Tom Lane wrote: > Andres Freund <and...@2ndquadrant.com> writes: > > On 2013-07-29 07:11:13 -0400, Stephen Frost wrote: > >> * Tom Lane (t...@sss.pgh.pa.us) wrote: > >>> The bottom line was: > >>> It looks like our choices are (1) teach configure to enable > >>> -fno-aggressive-loop-optimizations if the compiler recognizes it, > >>> or (2) back-port commit 8137f2c32322c624e0431fac1621e8e9315202f9. > >>> > >>> I am in favor of fixing the back branches via (1), because it's less > >>> work and much less likely to break third-party extensions. Some other > >>> people argued for (2), but I've not seen any patch emerge from them, > >>> and you can bet I'm not going to do it. > > >> Yea, just passing -fno-aggressive-loop-optimizations seems like the > >> safest and best option to me also.. > > > I think we need to do both. There very well might be other optimizations > > made based on the unreachability information. > > If we turn off the optimization, that will fix any other cases as well, > no? So why would we risk breaking third-party code by back-porting the > struct declaration changes?
The -fno-agressive-loop thingie afaics only controls the optimization with regard to loopey constructs, not in general. I *think* there are independent hazards with general unreachability detection. Not sure whether they trigger at -O2 or only at -O3 though. Greetings, Andres Freund -- Andres Freund http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
