Since we're not checking for the more general AllocationInst first, we need to explicitly check
that Object is an Argument before casting it to one.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47268 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/BasicAliasAnalysis.cpp b/lib/Analysis/BasicAliasAnalysis.cpp
index 5124376..fa5c5b8 100644
--- a/lib/Analysis/BasicAliasAnalysis.cpp
+++ b/lib/Analysis/BasicAliasAnalysis.cpp
@@ -272,7 +272,7 @@
       // If this is a tail call and P points to a stack location, we know that
       // the tail call cannot access or modify the local stack.
       if (isa<AllocaInst>(Object) ||
-          cast<Argument>(Object)->hasByValAttr())
+          (isa<Argument>(Object) && cast<Argument>(Object)->hasByValAttr()))
         if (CallInst *CI = dyn_cast<CallInst>(CS.getInstruction()))
           if (CI->isTailCall())
             return NoModRef;