[NFC][DebugInfo] Use iterator moveBefore at many call-sites (#123583)

As part of the "RemoveDIs" project, BasicBlock::iterator now carries a
debug-info bit that's needed when getFirstNonPHI and similar feed into
instruction insertion positions. Call-sites where that's necessary were
updated a year ago; but to ensure some type safety however, we'd like to
have all calls to moveBefore use iterators.

This patch adds a (guaranteed dereferenceable) iterator-taking
moveBefore, and changes a bunch of call-sites where it's obviously safe
to change to use it by just calling getIterator() on an instruction
pointer. A follow-up patch will contain less-obviously-safe changes.

We'll eventually deprecate and remove the instruction-pointer
insertBefore, but not before adding concise documentation of what
considerations are needed (very few).

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp b/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
index 1454305..7811677 100644
--- a/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
+++ b/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
@@ -886,7 +886,7 @@ BasicBlock *llvm::ehAwareSplitEdge(BasicBlock *BB, BasicBlock *Succ,
   if (LandingPadReplacement) {
     auto *NewLP = OriginalPad->clone();
     auto *Terminator = BranchInst::Create(Succ, NewBB);
-    NewLP->insertBefore(Terminator);
+    NewLP->insertBefore(Terminator->getIterator());
     LandingPadReplacement->addIncoming(NewLP, NewBB);
   } else {
     Value *ParentPad = nullptr;