http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59634
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- http://gcc.gnu.org/onlinedocs/gcc-4.8.2/gcc/Optimize-Options.html#index-param-935 l1-cache-line-size The size of cache line in L1 cache, in bytes. l1-cache-size The size of L1 cache, in kilobytes. l2-cache-size The size of L2 cache, in kilobytes. This is talking about data cache size.