From: Michel LESPINASSE <walken@zoy.org>
To: Carlo Wood <carlo@alinoe.com>
Cc: gcc@gcc.gnu.org
Subject: Re: issues with inlining
Date: Thu, 09 Jan 2003 21:40:00 -0000 [thread overview]
Message-ID: <20030109193921.GB31311@zoy.org> (raw)
In-Reply-To: <20021219012212.GA26426@alinoe.com>
Hi Carlo,
On Thu, Dec 19, 2002 at 02:22:12AM +0100, Carlo Wood wrote:
> The following problems have been spotted:
[quoted below]
Did you get any replies to your email ? I've complained about just the
same issues previously without much success... issues 1) and 2) being
the most important for me.
Cheers,
> 1) -Winline doesn't give me a warning when a function is
> not inlined, even while I am using the inline keyword
> for it.
> 2) g++ 3.2.1 seems to totally ignore the inline keyword
> and do as it pleases when being used with -O3.
> Unfortunately, I know better than the compiler what
> should be inlined - so, ignoring the inline keyword
> and inlining other functions results in much slower
> code.
> 3) Apparently gcc is still inlining "top down", meaning
> that when a() calls b() which calls c() which calls d(),
> then b() is inlined into a(), c() is inlined into
> d() and when then the function becomes too big, it
> stops. THIS IS HORRIBLE!!! This *definitely* needs
> to be changed into that d() is inlined into c(),
> and if the function isn't getting too big, then c()
> into b() etc.
> 4) The instruction limit that can be set with -finline-limit
> seems to count instructions before optimization...
> This means that I need to give a limit of 8000 instructions
> before everything is inlined - although after optimization
> hardly anything is left (maybe 50 to 100 instructions, way
> below the default 600 threshold).
> By the time I get my inner functions inlined this way,
> EVERYTHING is inlined (I get one big function call of
> 120,000 instructions :/ (after compiling 60 minutes)).
--
Michel "Walken" LESPINASSE
Is this the best that god can do ? Then I'm not impressed.
next prev parent reply other threads:[~2003-01-09 19:39 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-12-18 18:32 Carlo Wood
2003-01-09 21:40 ` Michel LESPINASSE [this message]
2003-01-09 21:50 ` Andrew Haley
2003-01-09 22:52 ` Michel LESPINASSE
2003-01-10 0:15 ` Carlo Wood
2003-01-19 19:16 ` Alexandre Oliva
2003-01-19 20:49 ` Diego Novillo
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