From 8ea94524ed4dee3238689f49f28e616fb183514c Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Mon, 18 May 2009 16:03:58 +0000
Subject: [PATCH] Fix ScalarEvolution::isLoopGuardedByCond to accept a null
 Loop*, for consistency with other routines that use a null Loop* to mean code
 not contained by any loop.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72008 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Analysis/ScalarEvolution.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index 30d6e7088c8..c53ec8a5f1a 100644
--- a/lib/Analysis/ScalarEvolution.cpp
+++ b/lib/Analysis/ScalarEvolution.cpp
@@ -3328,6 +3328,10 @@ ScalarEvolution::getPredecessorWithUniqueSuccessorForBB(BasicBlock *BB) {
 bool ScalarEvolution::isLoopGuardedByCond(const Loop *L,
                                           ICmpInst::Predicate Pred,
                                           const SCEV *LHS, const SCEV *RHS) {
+  // Interpret a null as meaning no loop, where there is obviously no guard
+  // (interprocedural conditions notwithstanding).
+  if (!L) return false;
+
   BasicBlock *Predecessor = getLoopPredecessor(L);
   BasicBlock *PredecessorDest = L->getHeader();