Date: Fri, 26 Jul 2013 11:54:25 -0700 From: John-Mark Gurney <jmg@funkthat.com> To: Andriy Gapon <avg@freebsd.org> Cc: freebsd-arch@freebsd.org Subject: Re: amd64: -O2 even with DEBUG Message-ID: <20130726185425.GS26412@funkthat.com> In-Reply-To: <51F221D4.8040308@FreeBSD.org> References: <51F221D4.8040308@FreeBSD.org>
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Andriy Gapon wrote this message on Fri, Jul 26, 2013 at 10:14 +0300:
> I wonder why amd64 is distinguished to have -O2 in COPTFLAGS even when DEBUG is
> defined. For all other archs it's -O for that case.
>
> Perhaps, this was discussed / explained in the past, but I would appreciate it
> being said again (or even written as a comment in kern.pre.mk).
It's probably because at least gcc produces terrible amd64 code w/o
it... It will constantly reload the register it uses to do relative
loads w/ the same value even though nothing changed... makes performance
suck...
--
John-Mark Gurney Voice: +1 415 225 5579
"All that I will do, has been done, All that I have, has not."
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