The "gcc.dg/compat/vector-1 -m32" test was broken after the MMX rewrite. The

function parameters weren't converted to use the correct type (x86_mmx). Add a
check, similar to the one in llvm-gcc, to see if we need the x86_mmx type for
that function parameter. If so, it coerces the type to be that.

llvm-svn: 116684