[dev.simd] simd, cmd/compile: mark simd vectors uncomparable
SIMD vector types are opqaue, and are expected to be operated with
methods. It is not always possible to compare the two vectors
efficiently. Instead of adding more magic to the compiler to
handle the == operator, mark the vector types uncomparable.
Change-Id: I4ca5d5e80ca7d8992dffa7b3c0386b75eb19cfa8
Reviewed-on: https://go-review.googlesource.com/c/go/+/705855 Reviewed-by: Junyang Shao <shaojunyang@google.com>
TryBot-Bypass: Cherry Mui <cherryyz@google.com> Reviewed-by: David Chase <drchase@google.com>