[SystemZ::TTI]  Recognize the higher cost of scalar i1 -> fp conversion

Scalar i1 to fp conversions are done with a branch sequence, so it should
have a higher cost.

Review: Ulrich Weigand
https://reviews.llvm.org/D53924

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@345818 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed