ppcf128 to i32 conversion and expand it into a code
sequence like in LegalizeDAG. This needs custom
ppc lowering of FP_ROUND_INREG, so turn that on and
make it work with LegalizeTypes. Probably PPC should
simply custom lower the original conversion.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58329 91177308-0d34-0410-b5e6-96231b3b80d8