[x86] don't try to create a vector integer inst for an SSE1 target
(PR30512)
This bug was introduced with:
http://reviews.llvm.org/rL272511
We need to restrict the lowering to v4f32 comparisons because that's
all SSE1 can handle.
This should fix:
https://llvm.org/bugs/show_bug.cgi?id=28044
This avoids a "Do not know how to custom type legalize this operation"
error when building the multimedia/ffmpeg port on i386 with SSE enabled.