Date: Mon, 9 Jul 2001 22:09:41 +1000 (EST) From: Bruce Evans <bde@zeta.org.au> To: Dag-Erling Smorgrav <des@ofug.org> Cc: arch@FreeBSD.ORG Subject: Re: -fno-builtin Message-ID: <Pine.BSF.4.21.0107092158160.87629-100000@besplex.bde.org> In-Reply-To: <xzpr8vqtjwh.fsf@flood.ping.uio.no>
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On 9 Jul 2001, Dag-Erling Smorgrav wrote:
> Bruce Evans <bde@zeta.org.au> writes:
> > Unfortunately, the inline function version doesn't work right, at least
> > on i386's: __builtin_strlen("foo") gives code that loads the constant
> > result 3, but the inline strlen("foo") gives code that scans the string.
>
> What about a macro?
>
> #define strlen(s) __builtin_strlen(s)
>
> Would this work?
I think it would work right except in broken code which "knows" that
strlen isn't a macro, e.g.:
size_t (*p)(const char *s) = strlen;
and in non-broken code that avoids the macro, e.g.:
size_t foo = (strlen)("123");
It only loses the optimization (if any) of using the builtin for non-broken
code.
This is only practical because there aren't many builtins for standard
functions.
Bruce
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