From a447e0f38f9236a61407ebed49cd16d08ddb3676 Mon Sep 17 00:00:00 2001
From: Nick Lewycky <nicholas@mxc.ca>
Date: Fri, 14 Oct 2011 09:38:46 +0000
Subject: [PATCH] An instruction's operands aren't necessarily instructions or
 constants. They could be arguments, for example.

No testcase because this is a bug-fix broken out of a larger optimization patch.

llvm-svn: 141951
---
 llvm/lib/Analysis/ScalarEvolution.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index f09f357c61cd..e0ac56c65e76 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -4764,7 +4764,8 @@ static Constant *EvaluateExpression(Value *V, const Loop *L,
   for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
     Instruction *Operand = dyn_cast<Instruction>(I->getOperand(i));
     if (!Operand) {
-      Operands[i] = cast<Constant>(I->getOperand(i));
+      Operands[i] = dyn_cast<Constant>(I->getOperand(i));
+      if (!Operands[i]) return 0;
       continue;
     }
     Constant *C = EvaluateExpression(Operand, L, Vals, TD);