http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53712
--- Comment #6 from Jeroen van Bemmel <jbemmel at zonnet dot nl> 2012-06-19 00:08:01 UTC --- There are more SSE4.2 instruction which allow an unaligned memory operand: * pcmpistri * pcmpistrm * pcmpestri * pcmpestrm * crc32 (and maybe others?) Did you catch them all?
