Reuse the values if they are constants: this is important so that we index into the right structure field
This fixes bug: BasicAA/2003-07-03-BasicAACrash.ll


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@7093 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/BasicAliasAnalysis.cpp b/lib/Analysis/BasicAliasAnalysis.cpp
index b56782b..8b34d25 100644
--- a/lib/Analysis/BasicAliasAnalysis.cpp
+++ b/lib/Analysis/BasicAliasAnalysis.cpp
@@ -288,8 +288,13 @@
     const Value *Op1 = GEP1->getOperand(i);
     const Value *Op2 = GEP2->getOperand(i);
     if (Op1 == Op2) {   // If they are equal, use a zero index...
-      Indices1.push_back(Constant::getNullValue(Op1->getType()));
-      Indices2.push_back(Indices1.back());
+      if (!isa<Constant>(Op1)) {
+        Indices1.push_back(Constant::getNullValue(Op1->getType()));
+        Indices2.push_back(Indices1.back());
+      } else {
+        Indices1.push_back((Value*)Op1);
+        Indices2.push_back((Value*)Op2);
+      }
     } else {
       if (const ConstantInt *Op1C = dyn_cast<ConstantInt>(Op1)) {
         // If this is an array index, make sure the array element is in range...