Gentoo Archives: gentoo-user

From: Richard Fish <bigfish@××××××××××.org>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] How to properly change CFLAGS ?
Date: Thu, 31 Aug 2006 11:20:08
1 On 8/30/06, Vladimir G. Ivanovic <vgivanovic@×××××××.net> wrote:
2 > On Mon, 2006-08-21 at 20:06 -0700, Richard Fish wrote:
3 > > -Os seems to take much less time and memory to compile than -O2 or -O3. And being a
4 > > ~arch user, time-to-compile is a nice thing to reduce.
5 >
6 > It is possible that one of my usual CFLAGS options (-Wall -march=k8
7 > -msse3 -pipe -O2 -ffast-math) overwhelms any -Os/-O2 execution time
9 Well it looks like I'll have to retract that statement in relation to
10 -Os/-O2. My current tests with -march=pentium4 -fweb -pipe
11 -fomit-frame-pointer for my laptop or -march=athlon64 -fweb -pipe for
12 my AMD box show a <5% difference in compile time between -Os and -O2.
14 I think there was a bigger difference in previous versions of gcc, but
15 I can't seem to find any notes or anything to support that belief...
17 Cheers,
18 -Richard
19 --
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