[TargetLowering] Add support for non-uniform vectors to BuildSDIV

This patch refactors the existing TargetLowering::BuildSDIV base implementation to support non-uniform constant vector denominators.

This is the last patch necessary to close PR36545

Differential Revision: https://reviews.llvm.org/D50765

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@339908 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed