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Description of problem:
The builtin strlen() produced a wrong value in the
short test program I included below.  Certain conditions
had to be met to reproduce the bug:
    * the char pointer variable had to be of global scope
    * the variable had to be referred to before
      incrementing

Upgrading Rawhide gcc RPMs from 3.1-0.11 to 3.1-0.21 has
fixed the bug. However, I could not find a bug report on
strlen() builtin in GNATS or RedHat Bugzilla.

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

// Compile this with Rawhide RPMs pertaining to gcc-3.1-0.11:
//     gcc -O2 -o strlen strlen.c

char *start;	// Must be of global scope to trigger the bug

int main()
{
	char *s = "test";
	start = s;
	// Must refer to "start" before incrementing to trigger the bug:
	printf("s \"%s\", len %d\n", s, start - s);
	start += strlen(s);
	printf("s \"%s\", len %d\n", s, start - s);
	return 0;
}

==============================================================


Version-Release number of selected component (if applicable):
gcc-3.1-0.11 et al.

How reproducible:
Always

Steps to Reproduce:
$ gcc -O2 -o strlen strlen.c
$ ./strlen



Actual Results:  
s "test", len 0
s "test", len 5



Expected Results:  
s "test", len 0
s "test", len 4



Additional info:

I submitted a similar report to GCC GNATS bug tracking
system today.