[SystemZ::TTI]  Accurate costs for i1->double vector conversions

This factors out a new method getBoolVecToIntConversionCost() containing the
code for vector sext/zext of i1, in order to reuse it for i1 to double vector
conversions.

Review: Ulrich Weigand
https://reviews.llvm.org/D53923

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@345817 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed