getCopyToParts problem was noticed by the new
LegalizeTypes infrastructure. In order to avoid
this kind of thing in the future I've added a
check that EXTRACT_ELEMENT is only used with
integers. Once LegalizeTypes is up and running
most likely BUILD_PAIR and EXTRACT_ELEMENT can
be removed, in favour of using apints instead.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48294 91177308-0d34-0410-b5e6-96231b3b80d8