[CSP, Cloning] Update DuplicateInstructionsInSplitBetween to use DomTreeUpdater.

This patch updates DuplicateInstructionsInSplitBetween to update a DTU
instead of applying updates to the DT directly.

Given that there only are 2 users, also updated them in this patch to
avoid churn.

I slightly moved the code in CallSiteSplitting around to reduce the
places where we have to pass in DTU. If necessary, I could split those
changes in a separate patch.

This fixes missing DT updates when dealing with musttail calls in
CallSiteSplitting, by using DTU->deleteBB.

Reviewers: junbuml, kuhar, NutshellySima, indutny, brzycki

Reviewed By: NutshellySima




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@346769 91177308-0d34-0410-b5e6-96231b3b80d8
6 files changed