[TLI] Refactor "is integer division cheap" queries.

This removes the isPow2SDivCheap() query, as it is not currently used in
any meaningful way. isIntDivCheap() no longer relies on a state variable
(as all in-tree target set it to false), but the interface allows querying
based on the type optimization level.

NFC.

Differential Revision: http://reviews.llvm.org/D12082

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245430 91177308-0d34-0410-b5e6-96231b3b80d8
6 files changed