https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88671
--- Comment #2 from Uroš Bizjak <ubizjak at gmail dot com> --- This is required by ABI, please see section 2.3.3 of i386 PSABI, where: The exceptions to parameters passed on stack are as follows: • The first three parameters of type __m64 are passed in %mm0, %mm1, and %mm2. So, clang is wrong.
