This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
GCC 8, ppc64-le and problems with -fstack-protector-strong
- From: Jeffrey Walton <noloader at gmail dot com>
- To: GCC Development <gcc at gcc dot gnu dot org>
- Date: Tue, 20 Feb 2018 03:40:05 -0500
- Subject: GCC 8, ppc64-le and problems with -fstack-protector-strong
- Authentication-results: sourceware.org; auth=none
- Reply-to: noloader at gmail dot com
Hi Everyone,
We are tracking an issue on ppc64-le and GCC 8. We can duplicate it on
GCC112 when using /opt/cfarm/gcc8-r257824 compiler. Also see
https://github.com/weidai11/cryptopp/issues/588.
We have the issue isolated, but its not really reduced yet. When '-O2
-fstack-protector-strong' is used during a compile then we have some
failed self tests. When '-O3 -fstack-protector-strong' is used during
a compile then everything is OK. (It is not backwards; -O3 is OK, and
-O2 is bad).
The source code is clean under the sanitizers on the platform. The
problem does not occur under GCC 4.8.5 (default compiler) and GCC 7
(installed at /opt/cfarm/gcc-latest).
The source file that is causing the problems under Power8 is
https://github.com/weidai11/cryptopp/blob/master/rijndael-simd.cpp#L536
. Its an awful file and nearly everything is inlined.
I've tried looking at the disassemblies but I don't have the knowledge
to spot the trouble. I'm not sure how to troubleshoot things further.
Suggestions on the next step would be very helpful.
Thanks in advance.