http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57862
--- Comment #2 from Gaetano Mendola <mendola at gmail dot com> --- I had 0. Putting 2 or 3 fixed the problem. Now my question is: who is faulty? Kernel configuration on this platform, the architecture, the compiler or even me ? BTW, compiling that code with clang even with 0 in /proc/cpu/alignment gives the right "result".