According to System V i386 ABI: the "__m64" type paramater and return va passed by MMX registers. But current implementation treats "__m64" as "i which results in parameter passing by stack and returning by EDX and EAX This patch fixes the bug (https://bugs.llvm.org/show_bug.cgi?id=41029).

According to System V i386 ABI: the ` __m64` type paramater and return value are passed by MMX registers. But current implementation treats ` __m64` as ` i64` which results in parameter passing by stack and returning by EDX and EAX. This patch fixes the bug (https://bugs.llvm.org/show_bug.cgi?id=41029).

According to System V i386 ABI: the "` __m64"` type paramater and return value are passed by MMX registers. But current implementation treats "` __m64"` as "i` i64` which results in parameter passing by stack and returning by EDX and EAX. This patch fixes the bug (https://bugs.llvm.org/show_bug.cgi?id=41029).