Index: lib/Analysis/LoopInfo.cpp
===================================================================
--- lib/Analysis/LoopInfo.cpp
+++ lib/Analysis/LoopInfo.cpp
@@ -360,12 +360,16 @@
 }
 
 BranchInst *Loop::getLoopGuardBranch() const {
-  assert(isLoopSimplifyForm() && "Only valid for loop in simplify form");
+  if (!isLoopSimplifyForm())
+    return nullptr;
+
   BasicBlock *Preheader = getLoopPreheader();
   BasicBlock *Latch = getLoopLatch();
-  assert(Preheader && Latch &&
-         "Expecting a loop with valid preheader and latch");
-  assert(isLoopExiting(Latch) && "Only valid for rotated loop");
+
+  // Expecting a loop with valid preheader and latch,
+  // and loop should be in rotate form.
+  if (!Preheader || !Latch || !isLoopExiting(Latch))
+    return nullptr;
 
   Instruction *LatchTI = Latch->getTerminator();
   if (!LatchTI || LatchTI->getNumSuccessors() != 2)