[DAGCombiner] Add one use check to fold (not (and x, y)) -> (or (not x), (not y))

Summary:
If the and has an additional use we shouldn't invert it. That creates an additional instruction.

While there add a one use check to the transform above that looked similar.

Reviewers: spatel, RKSimon

Reviewed By: RKSimon

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D43225

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@325019 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed