llvm-project

8ba341ee - [BranchFolding] Kill common hoisted debug instructions (#140091)

[BranchFolding] Kill common hoisted debug instructions (#140091) branch-folder hoists common instructions from TBB and FBB into their pred. Without this patch it achieves this by splicing the instructions from TBB and deleting the common ones in FBB. That moves the debug locations and debug instructions from TBB into the pred without modification, which is not ideal. Debug locations are handled in pull request 140063. This patch handles debug instructions - in the simplest way possible, which is to just kill (undef) them. We kill and hoist the ones in FBB as well as TBB because otherwise the fact there's an assignment on the code path is deleted (which might lead to a prior location extending further than it should). We might be able to do something smarter to preserve some variable locations in some cases, but this is the easiest not-incorrect thing to do.