[DebugInfo][RemoveDIs] Switch some insertion routines to use iterators (#75330)

As part of RemoveDIs, we need instruction insertion to be done with
iterators rather than instruction pointers, so that we can communicate
some debug-info facts about the position. This patch is an entirely
mechanical replacement of Instruction * with BasicBlock::iterator, plus
using insertBefore to insert some instructions because we don't have
iterator-taking constructors yet.

Sadly it's not NFC because it causes dbg.value intrinsics / their
DPValue equivalents to shift location.

1 files changed, 3 insertions, 2 deletions

diff --git a/llvm/lib/Transforms/Utils/LoopRotationUtils.cpp b/llvm/lib/Transforms/Utils/LoopRotationUtils.cpp
index 76280ed..504f443 100644
--- a/llvm/lib/Transforms/Utils/LoopRotationUtils.cpp
+++ b/llvm/lib/Transforms/Utils/LoopRotationUtils.cpp
@@ -708,12 +708,13 @@ bool LoopRotate::rotateLoop(Loop *L, bool SimplifiedLatch) {
       // as U1'' and U1' scopes will not be compatible wrt to the local restrict
 
       // Clone the llvm.experimental.noalias.decl again for the NewHeader.
-      Instruction *NewHeaderInsertionPoint = &(*NewHeader->getFirstNonPHI());
+      BasicBlock::iterator NewHeaderInsertionPoint =
+          NewHeader->getFirstNonPHIIt();
       for (NoAliasScopeDeclInst *NAD : NoAliasDeclInstructions) {
         LLVM_DEBUG(dbgs() << "  Cloning llvm.experimental.noalias.scope.decl:"
                           << *NAD << "\n");
         Instruction *NewNAD = NAD->clone();
-        NewNAD->insertBefore(NewHeaderInsertionPoint);
+        NewNAD->insertBefore(*NewHeader, NewHeaderInsertionPoint);
       }
 
       // Scopes must now be duplicated, once for OrigHeader and once for