commit 0159652058ca555b05db6a209fe9cf660c3bf8e6
Author: Stefan Pintilie <stefanp@ca.ibm.com>
Date:   Fri May 28 11:35:25 2021 -0500

    Revert "Return "[LoopDeletion] Break backedge if we can prove that the loop is exited on 1st iteration" (try 2)"
    
    This reverts commit be1a23203b1de655b8c7dac7549818d975a0cbbf.

diff --git a/llvm/lib/Transforms/Scalar/LoopDeletion.cpp b/llvm/lib/Transforms/Scalar/LoopDeletion.cpp
index 41be776ec141..fd0e983b6199 100644
--- a/llvm/lib/Transforms/Scalar/LoopDeletion.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopDeletion.cpp
@@ -17,7 +17,6 @@
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Analysis/GlobalsModRef.h"
-#include "llvm/Analysis/LoopIterator.h"
 #include "llvm/Analysis/LoopPass.h"
 #include "llvm/Analysis/MemorySSA.h"
 #include "llvm/Analysis/OptimizationRemarkEmitter.h"
@@ -136,168 +135,6 @@ static bool isLoopNeverExecuted(Loop *L) {
   return true;
 }
 
-static const SCEV *
-getSCEVOnFirstIteration(Value *V, Loop *L, ScalarEvolution &SE,
-                        DenseMap<Value *, const SCEV *> &FirstIterSCEV) {
-  // Fist, check in cache.
-  auto Existing = FirstIterSCEV.find(V);
-  if (Existing != FirstIterSCEV.end())
-    return Existing->second;
-  const SCEV *S = nullptr;
-  // TODO: Once ScalarEvolution supports getValueOnNthIteration for anything
-  // else but AddRecs, it's a good use case for it. So far, just consider some
-  // simple cases, like arithmetic operations.
-  Value *LHS, *RHS;
-  using namespace PatternMatch;
-  if (match(V, m_Add(m_Value(LHS), m_Value(RHS)))) {
-    const SCEV *LHSS = getSCEVOnFirstIteration(LHS, L, SE, FirstIterSCEV);
-    const SCEV *RHSS = getSCEVOnFirstIteration(RHS, L, SE, FirstIterSCEV);
-    S = SE.getAddExpr(LHSS, RHSS);
-  } else if (match(V, m_Sub(m_Value(LHS), m_Value(RHS)))) {
-    const SCEV *LHSS = getSCEVOnFirstIteration(LHS, L, SE, FirstIterSCEV);
-    const SCEV *RHSS = getSCEVOnFirstIteration(RHS, L, SE, FirstIterSCEV);
-    S = SE.getMinusSCEV(LHSS, RHSS);
-  } else if (match(V, m_Mul(m_Value(LHS), m_Value(RHS)))) {
-    const SCEV *LHSS = getSCEVOnFirstIteration(LHS, L, SE, FirstIterSCEV);
-    const SCEV *RHSS = getSCEVOnFirstIteration(RHS, L, SE, FirstIterSCEV);
-    S = SE.getMulExpr(LHSS, RHSS);
-  } else
-    S = SE.getSCEV(V);
-  assert(S && "Case not handled?");
-  FirstIterSCEV[V] = S;
-  return S;
-}
-
-// Try to prove that one of conditions that dominates the latch must exit on 1st
-// iteration.
-static bool canProveExitOnFirstIteration(Loop *L, DominatorTree &DT,
-                                         ScalarEvolution &SE, LoopInfo &LI) {
-  BasicBlock *Latch = L->getLoopLatch();
-
-  if (!Latch)
-    return false;
-
-  LoopBlocksRPO RPOT(L);
-  RPOT.perform(&LI);
-
-  BasicBlock *Header = L->getHeader();
-  // Blocks that are reachable on the 1st iteration.
-  SmallPtrSet<BasicBlock *, 4> LiveBlocks;
-  // Edges that are reachable on the 1st iteration.
-  DenseSet<BasicBlockEdge> LiveEdges;
-  LiveBlocks.insert(L->getHeader());
-
-  auto MarkLiveEdge = [&](BasicBlock *From, BasicBlock *To) {
-    assert(LiveBlocks.count(From) && "Must be live!");
-    LiveBlocks.insert(To);
-    LiveEdges.insert({ From, To });
-  };
-
-  auto MarkAllSuccessorsLive = [&](BasicBlock *BB) {
-    for (auto *Succ : successors(BB))
-      MarkLiveEdge(BB, Succ);
-  };
-
-  // Check if there is only one predecessor on 1st iteration. Note that because
-  // we iterate in RPOT, we have already visited all its (non-latch)
-  // predecessors.
-  auto GetSolePredecessorOnFirstIteration = [&](BasicBlock * BB)->BasicBlock * {
-    if (BB == Header)
-      return L->getLoopPredecessor();
-    BasicBlock *OnlyPred = nullptr;
-    for (auto *Pred : predecessors(BB))
-      if (OnlyPred != Pred && LiveEdges.count({ Pred, BB })) {
-        // 2 live preds.
-        if (OnlyPred)
-          return nullptr;
-        OnlyPred = Pred;
-      }
-
-    assert(OnlyPred && "No live predecessors?");
-    return OnlyPred;
-  };
-  DenseMap<Value *, const SCEV *> FirstIterSCEV;
-  SmallPtrSet<BasicBlock *, 4> Visited;
-
-  // Use the following algorithm to prove we never take the latch on the 1st
-  // iteration:
-  // 1. Traverse in topological order, so that whenever we visit a block, all
-  //    its predecessors are already visited.
-  // 2. If we can prove that the block may have only 1 predecessor on the 1st
-  //    iteration, map all its phis onto input from this predecessor.
-  // 3a. If we can prove which successor of out block is taken on the 1st
-  //     iteration, mark this successor live.
-  // 3b. If we cannot prove it, conservatively assume that all successors are
-  //     live.
-  for (auto *BB : RPOT) {
-    Visited.insert(BB);
-
-    // This block is not reachable on the 1st iterations.
-    if (!LiveBlocks.count(BB))
-      continue;
-
-    // Skip inner loops.
-    if (LI.getLoopFor(BB) != L) {
-      MarkAllSuccessorsLive(BB);
-      continue;
-    }
-
-    // If RPOT exists, we should never visit a block before all of its
-    // predecessors are visited. The only situation when this can be broken is
-    // irreducible CFG. Do not deal with such cases.
-    if (BB != Header)
-      for (auto *Pred : predecessors(BB))
-        if (!Visited.count(Pred))
-          return false;
-
-    // If this block has only one live pred, map its phis onto their SCEVs.
-    if (auto *OnlyPred = GetSolePredecessorOnFirstIteration(BB))
-      for (auto &PN : BB->phis()) {
-        if (!SE.isSCEVable(PN.getType()))
-          continue;
-        auto *Incoming = PN.getIncomingValueForBlock(OnlyPred);
-        if (DT.dominates(Incoming, BB->getTerminator())) {
-          const SCEV *IncSCEV =
-              getSCEVOnFirstIteration(Incoming, L, SE, FirstIterSCEV);
-          FirstIterSCEV[&PN] = IncSCEV;
-        }
-      }
-
-    using namespace PatternMatch;
-    ICmpInst::Predicate Pred;
-    Value *LHS, *RHS;
-    const BasicBlock *IfTrue, *IfFalse;
-    // TODO: Handle switches.
-    if (!match(BB->getTerminator(),
-               m_Br(m_ICmp(Pred, m_Value(LHS), m_Value(RHS)),
-                    m_BasicBlock(IfTrue), m_BasicBlock(IfFalse)))) {
-      MarkAllSuccessorsLive(BB);
-      continue;
-    }
-
-    if (!SE.isSCEVable(LHS->getType())) {
-      MarkAllSuccessorsLive(BB);
-      continue;
-    }
-
-    // Can we prove constant true or false for this condition?
-    const SCEV *LHSS = getSCEVOnFirstIteration(LHS, L, SE, FirstIterSCEV);
-    const SCEV *RHSS = getSCEVOnFirstIteration(RHS, L, SE, FirstIterSCEV);
-    // TODO: isKnownPredicateAt is more powerful, but it's too compile time
-    // consuming. So we avoid using it here.
-    if (SE.isKnownPredicate(Pred, LHSS, RHSS))
-      MarkLiveEdge(BB, BB->getTerminator()->getSuccessor(0));
-    else if (SE.isKnownPredicate(ICmpInst::getInversePredicate(Pred), LHSS,
-                                 RHSS))
-      MarkLiveEdge(BB, BB->getTerminator()->getSuccessor(1));
-    else
-      MarkAllSuccessorsLive(BB);
-  }
-
-  // We can break the latch if it wasn't live.
-  return !LiveEdges.count({ Latch, Header });
-}
-
 /// If we can prove the backedge is untaken, remove it.  This destroys the
 /// loop, but leaves the (now trivially loop invariant) control flow and
 /// side effects (if any) in place.
@@ -311,7 +148,7 @@ breakBackedgeIfNotTaken(Loop *L, DominatorTree &DT, ScalarEvolution &SE,
     return LoopDeletionResult::Unmodified;
 
   auto *BTC = SE.getBackedgeTakenCount(L);
-  if (!BTC->isZero() && !canProveExitOnFirstIteration(L, DT, SE, LI))
+  if (!BTC->isZero())
     return LoopDeletionResult::Unmodified;
 
   breakLoopBackedge(L, DT, SE, LI, MSSA);
diff --git a/llvm/test/Transforms/LoopDeletion/eval_first_iteration.ll b/llvm/test/Transforms/LoopDeletion/eval_first_iteration.ll
index bed479e408eb..98dafebe0df0 100644
--- a/llvm/test/Transforms/LoopDeletion/eval_first_iteration.ll
+++ b/llvm/test/Transforms/LoopDeletion/eval_first_iteration.ll
@@ -344,19 +344,17 @@ define i32 @test_ne_const() {
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    br label [[LOOP:%.*]]
 ; CHECK:       loop:
-; CHECK-NEXT:    [[SUM:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ]
+; CHECK-NEXT:    [[SUM:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[SUM_NEXT:%.*]], [[BACKEDGE:%.*]] ]
 ; CHECK-NEXT:    [[SUB:%.*]] = sub i32 4, [[SUM]]
 ; CHECK-NEXT:    [[IS_POSITIVE:%.*]] = icmp sgt i32 [[SUB]], 0
-; CHECK-NEXT:    br i1 [[IS_POSITIVE]], label [[BACKEDGE:%.*]], label [[IF_FALSE:%.*]]
+; CHECK-NEXT:    br i1 [[IS_POSITIVE]], label [[BACKEDGE]], label [[IF_FALSE:%.*]]
 ; CHECK:       if.false:
 ; CHECK-NEXT:    br label [[BACKEDGE]]
 ; CHECK:       backedge:
 ; CHECK-NEXT:    [[MERGE_PHI:%.*]] = phi i32 [ 0, [[IF_FALSE]] ], [ [[SUB]], [[LOOP]] ]
-; CHECK-NEXT:    [[SUM_NEXT:%.*]] = add i32 [[SUM]], [[MERGE_PHI]]
+; CHECK-NEXT:    [[SUM_NEXT]] = add i32 [[SUM]], [[MERGE_PHI]]
 ; CHECK-NEXT:    [[LOOP_COND:%.*]] = icmp ne i32 [[SUM_NEXT]], 4
-; CHECK-NEXT:    br i1 [[LOOP_COND]], label [[BACKEDGE_LOOP_CRIT_EDGE:%.*]], label [[DONE:%.*]]
-; CHECK:       backedge.loop_crit_edge:
-; CHECK-NEXT:    unreachable
+; CHECK-NEXT:    br i1 [[LOOP_COND]], label [[LOOP]], label [[DONE:%.*]]
 ; CHECK:       done:
 ; CHECK-NEXT:    [[SUM_NEXT_LCSSA:%.*]] = phi i32 [ [[SUM_NEXT]], [[BACKEDGE]] ]
 ; CHECK-NEXT:    ret i32 [[SUM_NEXT_LCSSA]]
@@ -396,19 +394,17 @@ define i32 @test_slt_const() {
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    br label [[LOOP:%.*]]
 ; CHECK:       loop:
-; CHECK-NEXT:    [[SUM:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ]
+; CHECK-NEXT:    [[SUM:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[SUM_NEXT:%.*]], [[BACKEDGE:%.*]] ]
 ; CHECK-NEXT:    [[SUB:%.*]] = sub i32 4, [[SUM]]
 ; CHECK-NEXT:    [[IS_POSITIVE:%.*]] = icmp sgt i32 [[SUB]], 0
-; CHECK-NEXT:    br i1 [[IS_POSITIVE]], label [[BACKEDGE:%.*]], label [[IF_FALSE:%.*]]
+; CHECK-NEXT:    br i1 [[IS_POSITIVE]], label [[BACKEDGE]], label [[IF_FALSE:%.*]]
 ; CHECK:       if.false:
 ; CHECK-NEXT:    br label [[BACKEDGE]]
 ; CHECK:       backedge:
 ; CHECK-NEXT:    [[MERGE_PHI:%.*]] = phi i32 [ 0, [[IF_FALSE]] ], [ [[SUB]], [[LOOP]] ]
-; CHECK-NEXT:    [[SUM_NEXT:%.*]] = add i32 [[SUM]], [[MERGE_PHI]]
+; CHECK-NEXT:    [[SUM_NEXT]] = add i32 [[SUM]], [[MERGE_PHI]]
 ; CHECK-NEXT:    [[LOOP_COND:%.*]] = icmp slt i32 [[SUM_NEXT]], 4
-; CHECK-NEXT:    br i1 [[LOOP_COND]], label [[BACKEDGE_LOOP_CRIT_EDGE:%.*]], label [[DONE:%.*]]
-; CHECK:       backedge.loop_crit_edge:
-; CHECK-NEXT:    unreachable
+; CHECK-NEXT:    br i1 [[LOOP_COND]], label [[LOOP]], label [[DONE:%.*]]
 ; CHECK:       done:
 ; CHECK-NEXT:    [[SUM_NEXT_LCSSA:%.*]] = phi i32 [ [[SUM_NEXT]], [[BACKEDGE]] ]
 ; CHECK-NEXT:    ret i32 [[SUM_NEXT_LCSSA]]
@@ -448,19 +444,17 @@ define i32 @test_ult_const() {
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    br label [[LOOP:%.*]]
 ; CHECK:       loop:
-; CHECK-NEXT:    [[SUM:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ]
+; CHECK-NEXT:    [[SUM:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[SUM_NEXT:%.*]], [[BACKEDGE:%.*]] ]
 ; CHECK-NEXT:    [[SUB:%.*]] = sub i32 4, [[SUM]]
 ; CHECK-NEXT:    [[IS_POSITIVE:%.*]] = icmp sgt i32 [[SUB]], 0
-; CHECK-NEXT:    br i1 [[IS_POSITIVE]], label [[BACKEDGE:%.*]], label [[IF_FALSE:%.*]]
+; CHECK-NEXT:    br i1 [[IS_POSITIVE]], label [[BACKEDGE]], label [[IF_FALSE:%.*]]
 ; CHECK:       if.false:
 ; CHECK-NEXT:    br label [[BACKEDGE]]
 ; CHECK:       backedge:
 ; CHECK-NEXT:    [[MERGE_PHI:%.*]] = phi i32 [ 0, [[IF_FALSE]] ], [ [[SUB]], [[LOOP]] ]
-; CHECK-NEXT:    [[SUM_NEXT:%.*]] = add i32 [[SUM]], [[MERGE_PHI]]
+; CHECK-NEXT:    [[SUM_NEXT]] = add i32 [[SUM]], [[MERGE_PHI]]
 ; CHECK-NEXT:    [[LOOP_COND:%.*]] = icmp ult i32 [[SUM_NEXT]], 4
-; CHECK-NEXT:    br i1 [[LOOP_COND]], label [[BACKEDGE_LOOP_CRIT_EDGE:%.*]], label [[DONE:%.*]]
-; CHECK:       backedge.loop_crit_edge:
-; CHECK-NEXT:    unreachable
+; CHECK-NEXT:    br i1 [[LOOP_COND]], label [[LOOP]], label [[DONE:%.*]]
 ; CHECK:       done:
 ; CHECK-NEXT:    [[SUM_NEXT_LCSSA:%.*]] = phi i32 [ [[SUM_NEXT]], [[BACKEDGE]] ]
 ; CHECK-NEXT:    ret i32 [[SUM_NEXT_LCSSA]]
@@ -500,19 +494,17 @@ define i32 @test_sgt_const() {
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    br label [[LOOP:%.*]]
 ; CHECK:       loop:
-; CHECK-NEXT:    [[SUM:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ]
+; CHECK-NEXT:    [[SUM:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[SUM_NEXT:%.*]], [[BACKEDGE:%.*]] ]
 ; CHECK-NEXT:    [[SUB:%.*]] = sub i32 4, [[SUM]]
 ; CHECK-NEXT:    [[IS_POSITIVE:%.*]] = icmp sgt i32 [[SUB]], 0
-; CHECK-NEXT:    br i1 [[IS_POSITIVE]], label [[BACKEDGE:%.*]], label [[IF_FALSE:%.*]]
+; CHECK-NEXT:    br i1 [[IS_POSITIVE]], label [[BACKEDGE]], label [[IF_FALSE:%.*]]
 ; CHECK:       if.false:
 ; CHECK-NEXT:    br label [[BACKEDGE]]
 ; CHECK:       backedge:
 ; CHECK-NEXT:    [[MERGE_PHI:%.*]] = phi i32 [ 0, [[IF_FALSE]] ], [ [[SUB]], [[LOOP]] ]
-; CHECK-NEXT:    [[SUM_NEXT:%.*]] = add i32 [[SUM]], [[MERGE_PHI]]
+; CHECK-NEXT:    [[SUM_NEXT]] = add i32 [[SUM]], [[MERGE_PHI]]
 ; CHECK-NEXT:    [[LOOP_COND:%.*]] = icmp sgt i32 [[SUM_NEXT]], 4
-; CHECK-NEXT:    br i1 [[LOOP_COND]], label [[BACKEDGE_LOOP_CRIT_EDGE:%.*]], label [[DONE:%.*]]
-; CHECK:       backedge.loop_crit_edge:
-; CHECK-NEXT:    unreachable
+; CHECK-NEXT:    br i1 [[LOOP_COND]], label [[LOOP]], label [[DONE:%.*]]
 ; CHECK:       done:
 ; CHECK-NEXT:    [[SUM_NEXT_LCSSA:%.*]] = phi i32 [ [[SUM_NEXT]], [[BACKEDGE]] ]
 ; CHECK-NEXT:    ret i32 [[SUM_NEXT_LCSSA]]
@@ -552,19 +544,17 @@ define i32 @test_ugt_const() {
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    br label [[LOOP:%.*]]
 ; CHECK:       loop:
-; CHECK-NEXT:    [[SUM:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ]
+; CHECK-NEXT:    [[SUM:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[SUM_NEXT:%.*]], [[BACKEDGE:%.*]] ]
 ; CHECK-NEXT:    [[SUB:%.*]] = sub i32 4, [[SUM]]
 ; CHECK-NEXT:    [[IS_POSITIVE:%.*]] = icmp sgt i32 [[SUB]], 0
-; CHECK-NEXT:    br i1 [[IS_POSITIVE]], label [[BACKEDGE:%.*]], label [[IF_FALSE:%.*]]
+; CHECK-NEXT:    br i1 [[IS_POSITIVE]], label [[BACKEDGE]], label [[IF_FALSE:%.*]]
 ; CHECK:       if.false:
 ; CHECK-NEXT:    br label [[BACKEDGE]]
 ; CHECK:       backedge:
 ; CHECK-NEXT:    [[MERGE_PHI:%.*]] = phi i32 [ 0, [[IF_FALSE]] ], [ [[SUB]], [[LOOP]] ]
-; CHECK-NEXT:    [[SUM_NEXT:%.*]] = add i32 [[SUM]], [[MERGE_PHI]]
+; CHECK-NEXT:    [[SUM_NEXT]] = add i32 [[SUM]], [[MERGE_PHI]]
 ; CHECK-NEXT:    [[LOOP_COND:%.*]] = icmp ugt i32 [[SUM_NEXT]], 4
-; CHECK-NEXT:    br i1 [[LOOP_COND]], label [[BACKEDGE_LOOP_CRIT_EDGE:%.*]], label [[DONE:%.*]]
-; CHECK:       backedge.loop_crit_edge:
-; CHECK-NEXT:    unreachable
+; CHECK-NEXT:    br i1 [[LOOP_COND]], label [[LOOP]], label [[DONE:%.*]]
 ; CHECK:       done:
 ; CHECK-NEXT:    [[SUM_NEXT_LCSSA:%.*]] = phi i32 [ [[SUM_NEXT]], [[BACKEDGE]] ]
 ; CHECK-NEXT:    ret i32 [[SUM_NEXT_LCSSA]]
@@ -604,24 +594,22 @@ define i32 @test_multiple_pred_const() {
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    br label [[LOOP:%.*]]
 ; CHECK:       loop:
-; CHECK-NEXT:    [[SUM:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ]
+; CHECK-NEXT:    [[SUM:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[SUM_NEXT:%.*]], [[BACKEDGE:%.*]] ]
 ; CHECK-NEXT:    [[SUB:%.*]] = sub i32 4, [[SUM]]
 ; CHECK-NEXT:    [[IS_POSITIVE:%.*]] = icmp sgt i32 [[SUB]], 0
 ; CHECK-NEXT:    br i1 [[IS_POSITIVE]], label [[IF_TRUE:%.*]], label [[IF_FALSE:%.*]]
 ; CHECK:       if.true:
 ; CHECK-NEXT:    switch i32 4, label [[FAILURE:%.*]] [
-; CHECK-NEXT:    i32 100, label [[BACKEDGE:%.*]]
+; CHECK-NEXT:    i32 100, label [[BACKEDGE]]
 ; CHECK-NEXT:    i32 200, label [[BACKEDGE]]
 ; CHECK-NEXT:    ]
 ; CHECK:       if.false:
 ; CHECK-NEXT:    br label [[BACKEDGE]]
 ; CHECK:       backedge:
 ; CHECK-NEXT:    [[MERGE_PHI:%.*]] = phi i32 [ 0, [[IF_FALSE]] ], [ [[SUB]], [[IF_TRUE]] ], [ [[SUB]], [[IF_TRUE]] ]
-; CHECK-NEXT:    [[SUM_NEXT:%.*]] = add i32 [[SUM]], [[MERGE_PHI]]
+; CHECK-NEXT:    [[SUM_NEXT]] = add i32 [[SUM]], [[MERGE_PHI]]
 ; CHECK-NEXT:    [[LOOP_COND:%.*]] = icmp ne i32 [[SUM_NEXT]], 4
-; CHECK-NEXT:    br i1 [[LOOP_COND]], label [[BACKEDGE_LOOP_CRIT_EDGE:%.*]], label [[DONE:%.*]]
-; CHECK:       backedge.loop_crit_edge:
-; CHECK-NEXT:    unreachable
+; CHECK-NEXT:    br i1 [[LOOP_COND]], label [[LOOP]], label [[DONE:%.*]]
 ; CHECK:       done:
 ; CHECK-NEXT:    [[SUM_NEXT_LCSSA:%.*]] = phi i32 [ [[SUM_NEXT]], [[BACKEDGE]] ]
 ; CHECK-NEXT:    ret i32 [[SUM_NEXT_LCSSA]]
diff --git a/llvm/test/Transforms/LoopDeletion/zero-btc.ll b/llvm/test/Transforms/LoopDeletion/zero-btc.ll
index 958de0505af7..413b0a877dd4 100644
--- a/llvm/test/Transforms/LoopDeletion/zero-btc.ll
+++ b/llvm/test/Transforms/LoopDeletion/zero-btc.ll
@@ -161,16 +161,14 @@ define void @test_multi_exit3(i1 %cond1) {
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    br label [[LOOP:%.*]]
 ; CHECK:       loop:
-; CHECK-NEXT:    [[IV:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ]
+; CHECK-NEXT:    [[IV:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[IV_INC:%.*]], [[LATCH:%.*]] ]
 ; CHECK-NEXT:    store i32 0, i32* @G, align 4
-; CHECK-NEXT:    br i1 [[COND1:%.*]], label [[LATCH:%.*]], label [[EXIT:%.*]]
+; CHECK-NEXT:    br i1 [[COND1:%.*]], label [[LATCH]], label [[EXIT:%.*]]
 ; CHECK:       latch:
 ; CHECK-NEXT:    store i32 1, i32* @G, align 4
-; CHECK-NEXT:    [[IV_INC:%.*]] = add i32 [[IV]], 1
+; CHECK-NEXT:    [[IV_INC]] = add i32 [[IV]], 1
 ; CHECK-NEXT:    [[BE_TAKEN:%.*]] = icmp ne i32 [[IV_INC]], 1
-; CHECK-NEXT:    br i1 [[BE_TAKEN]], label [[LATCH_LOOP_CRIT_EDGE:%.*]], label [[EXIT]]
-; CHECK:       latch.loop_crit_edge:
-; CHECK-NEXT:    unreachable
+; CHECK-NEXT:    br i1 [[BE_TAKEN]], label [[LOOP]], label [[EXIT]]
 ; CHECK:       exit:
 ; CHECK-NEXT:    ret void
 ;