Re: [COMMITTERS] pgsql: Disable -faggressive-loop-optimizations in gcc 4.8+ for pre-9.2

From: Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: [COMMITTERS] pgsql: Disable -faggressive-loop-optimizations in gcc 4.8+ for pre-9.2
Date: 2015-01-20 15:30:21
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Tom Lane wrote:
> Disable -faggressive-loop-optimizations in gcc 4.8+ for pre-9.2 branches.
> With this optimization flag enabled, recent versions of gcc can generate
> incorrect code that assumes variable-length arrays (such as oidvector)
> are actually fixed-length because they're embedded in some larger struct.
> The known instance of this problem was fixed in 9.2 and up by commit
> 8137f2c32322c624e0431fac1621e8e9315202f9 and followon work, which hides
> actually-variable-length catalog fields from the compiler altogether.
> And we plan to gradually convert variable-length fields to official
> "flexible array member" notation over time, which should prevent this type
> of bug from reappearing as gcc gets smarter. We're not going to try to
> back-port those changes into older branches, though, so apply this
> band-aid instead.

Would anybody object to me pushing this commit to branches 8.2 and 8.3?

Álvaro Herrera
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

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