GCC 4.8.4 generates faulty code with -O2 on aarch64

[Shay Gal-On]

How to replicate:

wget http://repo.varnish-cache.org/source/varnish-3.0.7.tar.gz
tar xf varnish-3.0.7.tar.gz
cd varnish-3.0.7
./configure && make -j
make check

make check fails (as does any use of varnish).
Same is passing with gcc 4.8.2 or if setting optimization to -O1.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: gcc-4.8 4.8.4-2ubuntu1~14.04
ProcVersionSignature: Ubuntu 3.18.0-14.20.15+thunder.2-generic 3.18.7
Uname: Linux 3.18.0-14.20-generic aarch64
ApportVersion: 2.14.1-0ubuntu3.13
Architecture: arm64
CurrentDesktop: XFCE
Date: Thu Sep 17 14:26:03 2015
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: gcc-4.8
UpgradeStatus: No upgrade log present (probably fresh install)

[Shay Gal-On (sgalon)]

This may be a bug in varnish instead of GCC.