[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, 11 insertions, 10 deletions

diff --git a/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp b/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
index 1e22eca..831b487 100644
--- a/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
@@ -105,8 +105,8 @@ static void ConnectProlog(Loop *L, Value *BECount, unsigned Count,
       // PrologLatch. When supporting multiple-exiting block loops, we can have
       // two or more blocks that have the LatchExit as the target in the
       // original loop.
-      PHINode *NewPN = PHINode::Create(PN.getType(), 2, PN.getName() + ".unr",
-                                       PrologExit->getFirstNonPHI());
+      PHINode *NewPN = PHINode::Create(PN.getType(), 2, PN.getName() + ".unr");
+      NewPN->insertBefore(PrologExit->getFirstNonPHIIt());
       // Adding a value to the new PHI node from the original loop preheader.
       // This is the value that skips all the prolog code.
       if (L->contains(&PN)) {
@@ -269,8 +269,8 @@ static void ConnectEpilog(Loop *L, Value *ModVal, BasicBlock *NewExit,
     for (PHINode &PN : Succ->phis()) {
       // Add new PHI nodes to the loop exit block and update epilog
       // PHIs with the new PHI values.
-      PHINode *NewPN = PHINode::Create(PN.getType(), 2, PN.getName() + ".unr",
-                                       NewExit->getFirstNonPHI());
+      PHINode *NewPN = PHINode::Create(PN.getType(), 2, PN.getName() + ".unr");
+      NewPN->insertBefore(NewExit->getFirstNonPHIIt());
       // Adding a value to the new PHI node from the unrolling loop preheader.
       NewPN->addIncoming(PN.getIncomingValueForBlock(NewPreHeader), PreHeader);
       // Adding a value to the new PHI node from the unrolling loop latch.
@@ -363,12 +363,13 @@ CloneLoopBlocks(Loop *L, Value *NewIter, const bool UseEpilogRemainder,
       BasicBlock *FirstLoopBB = cast<BasicBlock>(VMap[Header]);
       BranchInst *LatchBR = cast<BranchInst>(NewBB->getTerminator());
       IRBuilder<> Builder(LatchBR);
-      PHINode *NewIdx = PHINode::Create(NewIter->getType(), 2,
-                                        suffix + ".iter",
-                                        FirstLoopBB->getFirstNonPHI());
+      PHINode *NewIdx =
+          PHINode::Create(NewIter->getType(), 2, suffix + ".iter");
+      NewIdx->insertBefore(FirstLoopBB->getFirstNonPHIIt());
       auto *Zero = ConstantInt::get(NewIdx->getType(), 0);
       auto *One = ConstantInt::get(NewIdx->getType(), 1);
-      Value *IdxNext = Builder.CreateAdd(NewIdx, One, NewIdx->getName() + ".next");
+      Value *IdxNext =
+          Builder.CreateAdd(NewIdx, One, NewIdx->getName() + ".next");
       Value *IdxCmp = Builder.CreateICmpNE(IdxNext, NewIter, NewIdx->getName() + ".cmp");
       Builder.CreateCondBr(IdxCmp, FirstLoopBB, InsertBot);
       NewIdx->addIncoming(Zero, InsertTop);
@@ -912,8 +913,8 @@ bool llvm::UnrollRuntimeLoopRemainder(
     IRBuilder<> B2(NewPreHeader->getTerminator());
     Value *TestVal = B2.CreateSub(TripCount, ModVal, "unroll_iter");
     BranchInst *LatchBR = cast<BranchInst>(Latch->getTerminator());
-    PHINode *NewIdx = PHINode::Create(TestVal->getType(), 2, "niter",
-                                      Header->getFirstNonPHI());
+    PHINode *NewIdx = PHINode::Create(TestVal->getType(), 2, "niter");
+    NewIdx->insertBefore(Header->getFirstNonPHIIt());
     B2.SetInsertPoint(LatchBR);
     auto *Zero = ConstantInt::get(NewIdx->getType(), 0);
     auto *One = ConstantInt::get(NewIdx->getType(), 1);