diff --git a/include/clang/AST/Expr.h b/include/clang/AST/Expr.h
index d75d366..3745866 100644
--- a/include/clang/AST/Expr.h
+++ b/include/clang/AST/Expr.h
@@ -2051,9 +2051,11 @@
 class BlockExpr : public Expr {
 protected:
   BlockDecl *TheBlock;
+  bool HasBlockDeclRefExprs;
 public:
-  BlockExpr(BlockDecl *BD, QualType ty) : Expr(BlockExprClass, ty), 
-            TheBlock(BD) {}
+  BlockExpr(BlockDecl *BD, QualType ty, bool hasBlockDeclRefExprs)
+    : Expr(BlockExprClass, ty), 
+      TheBlock(BD), HasBlockDeclRefExprs(hasBlockDeclRefExprs) {}
 
   const BlockDecl *getBlockDecl() const { return TheBlock; }
   BlockDecl *getBlockDecl() { return TheBlock; }
@@ -2070,6 +2072,10 @@
   /// getFunctionType - Return the underlying function type for this block.
   const FunctionType *getFunctionType() const;
 
+  /// hasBlockDeclRefExprs - Return true iff the block has BlockDeclRefExpr
+  /// contained inside.
+  bool hasBlockDeclRefExprs() const { return HasBlockDeclRefExprs; }
+
   static bool classof(const Stmt *T) { 
     return T->getStmtClass() == BlockExprClass;
   }
diff --git a/lib/AST/ExprConstant.cpp b/lib/AST/ExprConstant.cpp
index 540a637..51c581a 100644
--- a/lib/AST/ExprConstant.cpp
+++ b/lib/AST/ExprConstant.cpp
@@ -260,7 +260,11 @@
   APValue VisitAddrLabelExpr(AddrLabelExpr *E)
       { return APValue(E, 0); }
   APValue VisitCallExpr(CallExpr *E);
-  APValue VisitBlockExpr(BlockExpr *E) { return APValue(E, 0); }
+  APValue VisitBlockExpr(BlockExpr *E) {
+    if (!E->hasBlockDeclRefExprs())
+      return APValue(E, 0);
+    return APValue();
+  }
   APValue VisitConditionalOperator(ConditionalOperator *E);
 };
 } // end anonymous namespace
diff --git a/lib/AST/StmtSerialization.cpp b/lib/AST/StmtSerialization.cpp
index a6cf01f..009a2dd 100644
--- a/lib/AST/StmtSerialization.cpp
+++ b/lib/AST/StmtSerialization.cpp
@@ -1290,11 +1290,14 @@
 void BlockExpr::EmitImpl(Serializer& S) const {
   S.Emit(getType());
   S.EmitOwnedPtr(TheBlock);
+  S.EmitBool(HasBlockDeclRefExprs);
 }
 
 BlockExpr* BlockExpr::CreateImpl(Deserializer& D, ASTContext& C) {
   QualType T = QualType::ReadVal(D);
-  return new BlockExpr(cast<BlockDecl>(D.ReadOwnedPtr<Decl>(C)),T);
+  BlockDecl *B = cast<BlockDecl>(D.ReadOwnedPtr<Decl>(C));
+  bool H = D.ReadBool();
+  return new BlockExpr(B,T,H);
 }
 
 void BlockDeclRefExpr::EmitImpl(Serializer& S) const {
diff --git a/lib/CodeGen/CGExprConstant.cpp b/lib/CodeGen/CGExprConstant.cpp
index 523014f..8cfd60c 100644
--- a/lib/CodeGen/CGExprConstant.cpp
+++ b/lib/CodeGen/CGExprConstant.cpp
@@ -382,6 +382,8 @@
   }
     
   llvm::Constant *VisitBlockExpr(const BlockExpr *E) {
+    assert (!E->hasBlockDeclRefExprs() && "global block with BlockDeclRefs");
+
     const char *Name = "";
     if (const NamedDecl *ND = dyn_cast<NamedDecl>(CGF->CurFuncDecl))
       Name = ND->getNameAsString().c_str();
@@ -615,7 +617,9 @@
       return CGM.GetAddrOfConstantCFString(S);
     }
     case Expr::BlockExprClass: {
-      return CGF->BuildBlockLiteralTmp(cast<BlockExpr>(E));
+      BlockExpr *B = cast<BlockExpr>(E);
+      if (!B->hasBlockDeclRefExprs())
+        return CGF->BuildBlockLiteralTmp(B);
     }
     }
 
diff --git a/lib/Sema/Sema.h b/lib/Sema/Sema.h
index 3eb68b5..2a4b465 100644
--- a/lib/Sema/Sema.h
+++ b/lib/Sema/Sema.h
@@ -2004,7 +2004,8 @@
   llvm::SmallVector<ParmVarDecl*, 8> Params;
   bool hasPrototype;
   bool isVariadic;
-  
+  bool hasBlockDeclRefExprs;
+
   BlockDecl *TheDecl;
   
   /// TheScope - This is the scope for the block itself, which contains
diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index 5d1d935..c95b5ee 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -865,6 +865,9 @@
   // as they do not get snapshotted.
   //
   if (CurBlock && ShouldSnapshotBlockValueReference(CurBlock, VD)) {
+    // Blocks that have these can't be constant.
+    CurBlock->hasBlockDeclRefExprs = true;
+
     // The BlocksAttr indicates the variable is bound by-reference.
     if (VD->getAttr<BlocksAttr>())
       return Owned(new (Context) BlockDeclRefExpr(VD, 
@@ -4331,6 +4334,7 @@
 
   BSI->ReturnType = 0;
   BSI->TheScope = BlockScope;
+  BSI->hasBlockDeclRefExprs = false;
 
   BSI->TheDecl = BlockDecl::Create(Context, CurContext, CaretLoc);
   PushDeclContext(BlockScope, BSI->TheDecl);
@@ -4442,7 +4446,7 @@
   BlockTy = Context.getBlockPointerType(BlockTy);
 
   BSI->TheDecl->setBody(Body.take());
-  return new (Context) BlockExpr(BSI->TheDecl, BlockTy);
+  return new (Context) BlockExpr(BSI->TheDecl, BlockTy, BSI->hasBlockDeclRefExprs);
 }
 
 Sema::ExprResult Sema::ActOnVAArg(SourceLocation BuiltinLoc,