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diff --git a/intern/cycles/scene/constant_fold.h b/intern/cycles/scene/constant_fold.h
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+++ b/intern/cycles/scene/constant_fold.h
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+/*
+ * Copyright 2011-2013 Blender Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef __CONSTANT_FOLD_H__
+#define __CONSTANT_FOLD_H__
+
+#include "kernel/svm/types.h"
+#include "util/types.h"
+
+CCL_NAMESPACE_BEGIN
+
+class Scene;
+class ShaderGraph;
+class ShaderInput;
+class ShaderNode;
+class ShaderOutput;
+
+class ConstantFolder {
+ public:
+  ShaderGraph *const graph;
+  ShaderNode *const node;
+  ShaderOutput *const output;
+
+  Scene *scene;
+
+  ConstantFolder(ShaderGraph *graph, ShaderNode *node, ShaderOutput *output, Scene *scene);
+
+  bool all_inputs_constant() const;
+
+  /* Constant folding helpers */
+  void make_constant(float value) const;
+  void make_constant(float3 value) const;
+  void make_constant_clamp(float value, bool clamp) const;
+  void make_constant_clamp(float3 value, bool clamp) const;
+  void make_zero() const;
+  void make_one() const;
+
+  /* Bypass node, relinking to another output socket. */
+  void bypass(ShaderOutput *output) const;
+
+  /* For closure nodes, discard node entirely or bypass to one of its inputs. */
+  void discard() const;
+  void bypass_or_discard(ShaderInput *input) const;
+
+  /* Bypass or make constant, unless we can't due to clamp being true. */
+  bool try_bypass_or_make_constant(ShaderInput *input, bool clamp = false) const;
+
+  /* Test if shader inputs of the current nodes have fixed values. */
+  bool is_zero(ShaderInput *input) const;
+  bool is_one(ShaderInput *input) const;
+
+  /* Specific nodes. */
+  void fold_mix(NodeMix type, bool clamp) const;
+  void fold_math(NodeMathType type) const;
+  void fold_vector_math(NodeVectorMathType type) const;
+  void fold_mapping(NodeMappingType type) const;
+};
+
+CCL_NAMESPACE_END
+
+#endif /* __CONSTANT_FOLD_H__ */