Tools versions:
# uname -a
Linux Beast 2.6.11-gentoo-r11 #2 Wed Jun 15 09:13:40 CEST 2005 x86_64 x86_64
x86_64 GNU/Linux

# gcc -v
Reading specs from /usr/lib/gcc/x86_64-pc-linux-gnu/3.4.4/specs
Configured with: ../gcc-3.4.4/configure --libexecdir=/usr/lib --enable-shared
--enable-languages=c,c++,f77,objc --enable-clocale=gnu --enable-threads=posix
--enable-__cxa_atexit
Thread model: posix
gcc version 3.4.4

# as --version
GNU assembler 2.16.1
Copyright 2005 Free Software Foundation, Inc.
This program is free software; you may redistribute it under the terms of
the GNU General Public License.  This program has absolutely no warranty.
This assembler was configured for a target of `x86_64-pc-linux-gnu'.

# /lib/libc.so.6
GNU C Library stable release version 2.3.5, by Roland McGrath et al. Copyright
(C) 2005 Free Software Foundation, Inc. This is free software; see the source
for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.
Compiled by GNU CC version 3.4.4.
Compiled on a Linux 2.6.11 system on 2005-07-05.
Available extensions:
        GNU libio by Per Bothner
        crypt add-on version 2.1 by Michael Glad and others
        Native POSIX Threads Library by Ulrich Drepper et al
        BIND-8.2.3-T5B
        NIS(YP)/NIS+ NSS modules 0.19 by Thorsten Kukuk
Thread-local storage support included.
For bug reporting instructions, please see:
<http://www.gnu.org/software/libc/bugs.html>.

Reproducible: Always

Steps to reproduce:

1. Untar release distribution of GCC 3.4.4
2. Make gcc-build directory
3. Configure GCC for building;
# CFLAGS="-pipe -O2 -march=athlon64 -fweb -ftracer -frename-registers
-fprofile-generate" LDFLAGS="${LDFLAGS} -fprofile-generate"
../gcc-3.4.4/configure --libexecdir=/usr/lib --enable-shared
--enable-languages=c,c++,objc,f77 --enable-clocale=gnu --enable-threads=posix
--enable-__cxa_atexit
4. Build GCC;
# make LDFLAGS="${LDFLAGS} -fprofile-generate"
5. Run testsuite on newly built GCC;
# make -k check

Result:

The testsuite barks out on one of torture tests;

Executing on host: /root/gcc-build/gcc/xgcc -B/root/gcc-build/gcc/   -O1  -w -c
 -o 20010404-1.o
/root/gcc-3.4.4/gcc/testsuite/gcc.c-torture/compile/20010404-1.c    (timeout = 300)
profiling:/root/gcc-build/gcc/simplify-rtx.gcda:Overflow writing
output is: profiling:/root/gcc-build/gcc/simplify-rtx.gcda:Overflow writing

and continues barking onwards with;

profiling:/root/gcc-build/gcc/simplify-rtx.gcda:Overflow writing
output is: profiling:/root/gcc-build/gcc/simplify-rtx.gcda:Overflow writing

on every test that follows for gcc suite.

Expected result:

The same as without -fprofile-generate.

Notes:

I have marked this critical since there is no way I can use coverage for second
build;
# gcov -f /root/gcc-build/gcc/simplify-rtx
simplify-rtx.gcno:cannot open graph file
Though the file is there and readable, IMHO the format is corrupted by libgcov
itself because of the "Overflow writing" error. I have seen this error with
-fprofile-generate in other packages also (Python 2.4.1), so this is not GCC
coverage profile specific. 

Regards