Change LowerFP_TO_SINT to create the specific code it needs instead of

Change LowerFP_TO_SINT to create the specific code it needs instead of
unconditionally creating an i64 bitcast.  With the future legalizer
design, operation legalization can't introduce new nodes with illegal
types.

This fixes the rest of olden on ppc32.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43005 91177308-0d34-0410-b5e6-96231b3b80d8