g++ -O2 -o test test.cpp
./test

Gauthier's counterexample:

$ gcc-4.7 -Ofast -o bench_alignment_unaligned bench_alignment_unaligned.c
$ gcc-4.7 -Ofast -o bench_alignment bench_alignment.c
$ ./bench_alignment
result = -1223964992, time = 38
$ ./bench_alignment_unaligned 
result = 490453024, time = 57
