diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -10718,7 +10718,11 @@
                                               const SCEVAddRecExpr *LHS,
                                               const SCEV *RHS) {
   const Loop *L = LHS->getLoop();
-  return isLoopEntryGuardedByCond(L, Pred, LHS->getStart(), RHS) &&
+  const SCEV *Start = LHS->getStart();
+  if (!isAvailableAtLoopEntry(Start, L))
+    return false;
+
+  return isLoopEntryGuardedByCond(L, Pred, Start, RHS) &&
          isLoopBackedgeGuardedByCond(L, Pred, LHS->getPostIncExpr(*this), RHS);
 }
 
diff --git a/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp b/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
--- a/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
+++ b/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
@@ -1282,6 +1282,7 @@
     MadeAnyChanges = true;
     ToMove->moveBefore(*ExitBlock, InsertPt);
     SE->forgetBlockAndLoopDispositions(ToMove);
+    SE->forgetValue(ToMove);
     if (Done) break;
     InsertPt = ToMove->getIterator();
   }