From owner-freebsd-hackers  Fri Aug 24 13:36:28 2001
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Date: Fri, 24 Aug 2001 15:36:23 -0500
From: Dan Nelson <dnelson@emsphone.com>
To: John Baldwin <jhb@FreeBSD.ORG>
Cc: Leo Bicknell <bicknell@ufp.org>,
	"David O'Brien" <obrien@FreeBSD.ORG>, freebsd-hackers@FreeBSD.ORG,
	Steve Roome <stephen_roome@yahoo.com>
Subject: Re: function calls/rets in assembly
Message-ID: <20010824153622.A17762@dan.emsphone.com>
References: <20010824161024.A45122@ussenterprise.ufp.org> <XFMail.010824133134.jhb@FreeBSD.org>
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In the last episode (Aug 24), John Baldwin said:
> On 24-Aug-01 Leo Bicknell wrote:
> > Someone suggested to me privately turning on optimization, for the
> > record that doesn't help much: (with -O2)
> 
> Actually, it's fairly close to what I proposed.  It even axed the
> addl after the call.  The only weirdness is the subl/addl dinking
> with gcc.  I've no idea what that is about.  Perhaps it is using that
> to align code to a certain boundary to optimize the ret inside
> printf?  (Make it fetch at the start of a cache line or some such.)

For what it's worth, gcc30 -O produces:

        .align 4
.globl printasint
        .type   printasint,@function
printasint:
        pushl   %ebp
        movl    %esp, %ebp
        subl    $16, %esp
        pushl   8(%ebp)
        pushl   $.LC0
        call    printf
        leave
        ret
 
-- 
	Dan Nelson
	dnelson@emsphone.com

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