[DAGCombiner] Push truncate through adde when the carry isn't used.

Summary: As per title.

Reviewers: mkuper, spatel, bkramer, RKSimon, zvi

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D29528

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@294394 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed