This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: Re : gcc 3.4 > mainline performance regression
- From: Andrew Haley <aph at redhat dot com>
- To: Mick CORNUT <mick_cornut at yahoo dot fr>
- Cc: Steven Bosscher <stevenb dot gcc at gmail dot com>, David Edelsohn <dje at watson dot ibm dot com>, gcc at gcc dot gnu dot org
- Date: Fri, 5 Jan 2007 18:27:08 +0000
- Subject: Re: Re : gcc 3.4 > mainline performance regression
- References: <20070105182235.27516.qmail@web28008.mail.ukl.yahoo.com>
Please don't top-post. It's very confusing.
Mick CORNUT writes:
> I don't know exactly if I've understood all your previous
> explanation (excepted the load & store motion part), but we pointed
> out 2 different problems:
>
> Pb n°1: depending on the optimization level -03, a[0] and a[1] are
> being loaded and stored on each loop iteration
> Pb n°2: depending on the optimization level -0s, the max range
> limit value (1.000.000) is loaded on each loop iteration
> (previously in gcc 3.4.2, it was loaded once, then the register
> holding it was decremented by one until null flag detected)
>
> It seems to me that your current remaks only apply to Pb n°1, am I wrong?
That's right.
Andrew.