Message-ID: <3E29919E.B202D5DD@yahoo.com>
Date: Sat, 18 Jan 2003 12:40:46 -0500
From: CBFalconer <cbfalconer AT yahoo DOT com>
Organization: Ched Research
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To: djgpp-workers AT delorie DOT com
Subject: Re: gcc 3.2.1 optimizer degradation (strlen, -O2)
References: <2 DOT 7 DOT 9 DOT 181SX DOT H8JVM1 AT pauzner DOT dnttm DOT ru>
	    <2561-Sat11Jan2003175230+0200-eliz AT is DOT elta DOT co DOT il> <2 DOT 7 DOT 9 DOT 2 DOT H8WXRK AT pauzner DOT dnttm DOT ru>
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Reply-To: djgpp-workers AT delorie DOT com

Leonid Pauzner wrote:
> 11-Jan-2003 23:33 Marcel Cox wrote:
> 
> > 3) Except for Pentium4, GCC 3.2.1 does not inline the strlen
> > function in your code as it considers the gain to be not
> > worthwhile. You can however force it to do so anyway by using
> > the option -minline-all-stringops and see if that makes a
> > difference.
> 
> Apparently, gcc 3.2.1 __builtin_strlen() never inlined on
> Pentium 90MHz so the following function hangs:

I tried the following and got no hangs, but nothing seems to cause
the very simple inline string instructions to be used.  Running on
a 486, gcc 3.2.1.  I am surprised, because I found earlier that
memcpy() does use them.

/* Compile with -Wa,-alhn=strlgh.s to show code generated */
/*  also try -minline-all-stringops */

#include <stdio.h>
#include <string.h>

char *s = "This is a string";

int main(int argc, char *argv[])
{
   int lgh;

   lgh = strlen(s);
   printf("%d %s\n", lgh, s);
   if (argc)
      while (--argc) {
         lgh = strlen(argv[argc]);
         printf("%d %s\n", lgh, argv[argc]);
      }
   return 0;
}

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Chuck F (cbfalconer AT yahoo DOT com) (cbfalconer AT worldnet DOT att DOT net)
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