Subject: Re: bug#76559: 31.0.50; [-O3 + PGTK] Crash when 'copying as kill'/'killing word'

From: Eli Zaretskii <[email-masked]>
Date: Thu, 27 Feb 2025 10:41:30 +0200

> From: Po Lu <[email-masked]>
> Cc: Iurie Marian <[email-masked]>,  [email-masked],
>   [email-masked],  [email-masked]
> Date: Thu, 27 Feb 2025 13:36:59 +0800
> 
> Eli Zaretskii <[email-masked]> writes:
> 
> >  Po Lu, any suggestions or ideas?
> 
> I replied to Pip Cet.  It's likely a GCC bug, and one which I cannot
> reproduce in 14.2.1 or the recentest GCC 15 snapshot, rather than
> undefined behavior in any sense...

Thanks.

I believe we should recommend against using -O3.  Too many bad bugs
happened recently, especially in the latest and hottest versions of
GCC to justify such a recommendation.  Especially since using -O3 is
extremely unlikely to produce tangible performance advantages (if
someone has data to the contrary, I'd be interested in seeing it), due
to very large inner loops in our code.  Moreover, the excessive
inlining affected by -O3 could well cause CPU caches to overflow, so
it could well be a net loss in performance.