[NFC][RemoveDIs] Prefer iterator-insertion over instructions

Continuing the patch series to get rid of debug intrinsics [0], instruction
insertion needs to be done with iterators rather than instruction pointers,
so that we can communicate information in the iterator class. This patch
adds an iterator-taking insertBefore method and converts various call sites
to take iterators. These are all sites where such debug-info needs to be
preserved so that a stage2 clang can be built identically; it's likely that
many more will need to be changed in the future.

At this stage, this is just changing the spelling of a few operations,
which will eventually become signifiant once the debug-info bearing
iterator is used.

[0] https://discourse.llvm.org/t/rfc-instruction-api-changes-needed-to-eliminate-debug-intrinsics-from-ir/68939

Differential Revision: https://reviews.llvm.org/D152537

1 files changed, 5 insertions, 3 deletions

diff --git a/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp b/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
index 629062d8..7c081cb 100644
--- a/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
+++ b/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
@@ -852,9 +852,11 @@ void llvm::createPHIsForSplitLoopExit(ArrayRef<BasicBlock *> Preds,
         continue;
 
     // Otherwise a new PHI is needed. Create one and populate it.
-    PHINode *NewPN = PHINode::Create(
-        PN.getType(), Preds.size(), "split",
-        SplitBB->isLandingPad() ? &SplitBB->front() : SplitBB->getTerminator());
+    PHINode *NewPN = PHINode::Create(PN.getType(), Preds.size(), "split");
+    BasicBlock::iterator InsertPos =
+        SplitBB->isLandingPad() ? SplitBB->begin()
+                                : SplitBB->getTerminator()->getIterator();
+    NewPN->insertBefore(InsertPos);
     for (BasicBlock *BB : Preds)
       NewPN->addIncoming(V, BB);