[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/IR/DIBuilder.cpp b/llvm/lib/IR/DIBuilder.cpp
index d9bd4f1..8f9462ab 100644
--- a/llvm/lib/IR/DIBuilder.cpp
+++ b/llvm/lib/IR/DIBuilder.cpp
@@ -1013,7 +1013,7 @@ DbgInstPtr DIBuilder::insertDbgAssign(Instruction *LinkedInstr, Value *Val,
   B.SetCurrentDebugLocation(DL);
 
   auto *DVI = cast<DbgAssignIntrinsic>(B.CreateCall(AssignFn, Args));
-  DVI->insertAfter(LinkedInstr);
+  DVI->insertAfter(LinkedInstr->getIterator());
   return DVI;
 }