Re: Bison 3.0 updates

On 2013-07-29 07:11:13 -0400, Stephen Frost wrote:
> * Tom Lane (tgl(at)sss(dot)pgh(dot)pa(dot)us) wrote:
> > Stephen Frost <sfrost(at)snowman(dot)net> writes:
> > > However, I comment on this mainly because anchovy has had issues with
> > > 9.1 and older for some time, which looks like an issue with GCC 4.8.0.
> > > Did you happen to resolve or identify what is happening there..?
> >
> > Yeah, we know about that:
> > http://www.postgresql.org/message-id/14242.1365200084@sss.pgh.pa.us
>
> Ah, right, read the thread but didn't attach it to anchovy.
>
> > 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. Like concluding some
conditional block isn't reachable. (1) would be back branches only,
right?

If others aggree I'll happily (ok, that's a blatant lie), provide
patches if that actually helps $committer.

Greetings,

Andres Freund

--
Andres Freund http://www.2ndQuadrant.com/
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