diff --git a/Makefile b/Makefile
index 7daddbd955af..e7dcebc3c586 100644
--- a/Makefile
+++ b/Makefile
@@ -37,7 +37,7 @@ LIBHALIDEIR:
 	+ cd HalideIR; make lib/libHalideIR.a ; cd $(ROOTDIR)
 
 lint:
-	python2 dmlc-core/scripts/lint.py tvm cpp include src
+	python2 dmlc-core/scripts/lint.py tvm all include src python
 
 doc:
 	doxygen docs/Doxyfile
diff --git a/dmlc-core b/dmlc-core
index f294fc2271b2..749e570c1942 160000
--- a/dmlc-core
+++ b/dmlc-core
@@ -1 +1 @@
-Subproject commit f294fc2271b27b0b6e2b117003ed2dc3d3ba8fda
+Subproject commit 749e570c19423fe679a5f496e2394ba3bed75a16
diff --git a/include/tvm/buffer.h b/include/tvm/buffer.h
new file mode 100644
index 000000000000..beed7e9d1281
--- /dev/null
+++ b/include/tvm/buffer.h
@@ -0,0 +1,98 @@
+
+/*!
+ *  Copyright (c) 2016 by Contributors
+ * \file buffer.h
+ * \brief Symbolic n-dimensional array, to represent a memory buffer.
+ */
+#ifndef TVM_BUFFER_H_
+#define TVM_BUFFER_H_
+
+#include <tvm/container.h>
+#include <string>
+
+#include "./base.h"
+#include "./expr.h"
+
+namespace tvm {
+
+// Internal node container Buffer
+class BufferNode;
+/*!
+ * \brief Buffer is a symbolic n-darray structure.
+ *  It is a composition of primitive symbolic types,
+ *  used to specify input/output strcuture of the program.
+ */
+class Buffer : public NodeRef {
+ public:
+  Buffer() {}
+  explicit Buffer(std::shared_ptr<Node> n) : NodeRef(n) {}
+  /*!
+   * \brief construct a new buffer based on shape and strides.
+   */
+  explicit Buffer(Array<Expr> shape,
+                  Type dtype = Float(32),
+                  std::string name = "buffer");
+  /*!
+   * \brief Generate a load expression loading the index location of buffer.
+   * \param index The index to the buffer.
+   * \return The load expression.
+   */
+  Expr MakeLoad(Array<Expr> index) const;
+  /*!
+   * \brief Generate a store statement.
+   * \param index The index to the buffer.
+   * \param value The value to be stored.
+   * \return The load expression.
+   */
+  Stmt MakeStore(Array<Expr> index, Expr value) const;
+  /*!
+   * \brief access the internal node container
+   * \return the pointer to the internal node container
+   */
+  inline const BufferNode* operator->() const;
+};
+
+/*! \brief Node to represent a buffer */
+class BufferNode : public Node {
+ public:
+  /*! \brief optional name of the buffer */
+  std::string name;
+  /*! \brief The pointer to the head of the data */
+  Var ptr;
+  /*! \brief The shape of the buffer */
+  Array<Expr> shape;
+  /*!
+   * \brief The strides of each dimension
+   *  This can be an empty array, indicating array is contiguous
+   */
+  Array<Expr> strides;
+  /*! \brief data type in the content of the tensor */
+  Type dtype;
+  // Maybe need more information(alignment) later
+  /*! \brief constructor */
+  BufferNode() {}
+
+  void VisitAttrs(AttrVisitor* v) final {
+    v->Visit("name", &name);
+    v->Visit("ptr", &ptr);
+    v->Visit("shape", &shape);
+    v->Visit("strides", &strides);
+    v->Visit("dtype", &dtype);
+  }
+
+  static Buffer make(std::string name,
+                     Var ptr,
+                     Array<Expr> shape,
+                     Array<Expr> strides,
+                     Type dtype);
+
+  static constexpr const char* _type_key = "Buffer";
+  TVM_DECLARE_NODE_TYPE_INFO(BufferNode);
+};
+
+inline const BufferNode* Buffer::operator->() const {
+  return static_cast<const BufferNode*>(node_.get());
+}
+
+}  // namespace tvm
+#endif  // TVM_BUFFER_H_
diff --git a/include/tvm/ir_pass.h b/include/tvm/ir_pass.h
index c93d748a1856..d4456ed74cd4 100644
--- a/include/tvm/ir_pass.h
+++ b/include/tvm/ir_pass.h
@@ -13,6 +13,7 @@
 #include <unordered_map>
 #include <vector>
 #include "./expr.h"
+#include "./buffer.h"
 #include "./schedule.h"
 
 namespace tvm {
@@ -56,10 +57,22 @@ Stmt ConvertSSA(Stmt stmt);
  *
  * \note All the passes in this file uses SSA form and outputs SSA form.
  */
-Stmt Inline(FunctionRef f,
+Stmt Inline(Stmt stmt,
+            FunctionRef f,
             Array<Var> args,
-            Expr body,
-            Stmt stmt);
+            Expr body);
+
+
+/*!
+ * \brief Flatten the multi-dimensional read/write
+ *  to single dimensional Load/Store
+ *
+ * \param stmt The stmt to be trasnformed.
+ * \param extern_buffer Map specifies external
+ *    buffer assignment of input and outputs.
+ */
+Stmt StorageFlatten(Stmt stmt,
+                    Map<Tensor, Buffer> extern_buffer);
 
 }  // namespace ir
 }  // namespace tvm
diff --git a/python/tvm/__init__.py b/python/tvm/__init__.py
index 07fca6ecab39..3725cd62c15d 100644
--- a/python/tvm/__init__.py
+++ b/python/tvm/__init__.py
@@ -1,3 +1,4 @@
+# pylint: disable=redefined-builtin, wildcard-import
 """C++ backend related python scripts"""
 from __future__ import absolute_import as _abs
 from ._ctypes._api import register_node
diff --git a/python/tvm/_base.py b/python/tvm/_base.py
index 88ac476ecc6f..b67275cb4030 100644
--- a/python/tvm/_base.py
+++ b/python/tvm/_base.py
@@ -1,10 +1,9 @@
 # coding: utf-8
-# pylint: disable=invalid-name
+# pylint: disable=invalid-name, no-member
 """ ctypes library of nnvm and helper functions """
 from __future__ import absolute_import
 
 import sys
-import os
 import ctypes
 import numpy as np
 from . import libinfo
diff --git a/python/tvm/_ctypes/_api.py b/python/tvm/_ctypes/_api.py
index c9d980928967..4de64f9db4b6 100644
--- a/python/tvm/_ctypes/_api.py
+++ b/python/tvm/_ctypes/_api.py
@@ -1,5 +1,6 @@
 # coding: utf-8
 # pylint: disable=invalid-name, protected-access, too-many-arguments, too-many-lines
+# pylint: disable=attribute-defined-outside-init, no-member, missing-docstring
 """Symbolic configuration API."""
 from __future__ import absolute_import as _abs
 
@@ -14,6 +15,7 @@
 from .. import _function_internal
 
 class ArgVariant(ctypes.Union):
+    """ArgVariant in C API"""
     _fields_ = [("v_long", ctypes.c_long),
                 ("v_double", ctypes.c_double),
                 ("v_str", ctypes.c_char_p),
@@ -30,8 +32,8 @@ class ArgVariant(ctypes.Union):
 
 def _return_node(x):
     handle = x.v_handle
-    if not isinstance(handle, ctypes.c_void_p):
-        handle = ctypes.c_void_p(handle)
+    if not isinstance(handle, NodeHandle):
+        handle = NodeHandle(handle)
     ret_val = ArgVariant()
     ret_typeid = ctypes.c_int()
     ret_success = ctypes.c_int()
@@ -47,7 +49,7 @@ def _return_node(x):
     kLong: lambda x: x.v_long,
     kDouble: lambda x: x.v_double,
     kStr: lambda x: py_str(x.v_str),
-    kNodeHandle: lambda x: _return_node(x)
+    kNodeHandle: _return_node
 }
 
 class SliceBase(object):
@@ -251,6 +253,7 @@ def register_node(type_key=None):
     """
     if isinstance(type_key, str):
         def register(cls):
+            """internal register function"""
             NODE_TYPE[type_key] = cls
             return cls
         return register
@@ -273,9 +276,9 @@ def _init_function_module(root_namespace):
     module_obj = sys.modules["%s.function" % root_namespace]
     module_internal = sys.modules["%s._function_internal" % root_namespace]
     namespace_match = {
-        "_make_" : sys.modules["%s.make" % root_namespace],
-        "_pass_" : sys.modules["%s.ir_pass" % root_namespace],
-        "_schedule_" : sys.modules["%s.schedule" % root_namespace]
+        "_make_": sys.modules["%s.make" % root_namespace],
+        "_pass_": sys.modules["%s.ir_pass" % root_namespace],
+        "_schedule_": sys.modules["%s.schedule" % root_namespace]
     }
 
     for name in op_names:
diff --git a/python/tvm/collections.py b/python/tvm/collections.py
index eb988930408d..85e629cc96da 100644
--- a/python/tvm/collections.py
+++ b/python/tvm/collections.py
@@ -1,3 +1,4 @@
+# pylint: disable=protected-access, no-member
 """Collection structure in the high level DSL."""
 from __future__ import absolute_import as _abs
 from ._ctypes._api import NodeBase, register_node
@@ -6,6 +7,7 @@
 
 @register_node
 class Array(NodeBase):
+    """Array container of TVM"""
     def __getitem__(self, i):
         if i >= len(self):
             raise IndexError("array index out ot range")
@@ -19,6 +21,7 @@ def __repr__(self):
 
 @register_node
 class Map(NodeBase):
+    """Map container of TVM"""
     def __getitem__(self, k):
         return _function_internal._MapGetItem(self, k)
 
@@ -26,6 +29,7 @@ def __contains__(self, k):
         return _function_internal._MapCount(self, k) != 0
 
     def items(self):
+        """Get the items from the map"""
         akvs = _function_internal._MapItems(self)
         return [(akvs[i], akvs[i+1]) for i in range(0, len(akvs), 2)]
 
@@ -38,9 +42,17 @@ def __repr__(self):
 
 @register_node
 class Range(NodeBase):
+    """Represent range in TVM"""
     pass
 
 
 @register_node
 class IterVar(NodeBase, _expr.ExprOp):
+    """Represent iteration variable."""
+    pass
+
+
+@register_node
+class Buffer(NodeBase):
+    """Represent a Buffer in TVM."""
     pass
diff --git a/python/tvm/expr.py b/python/tvm/expr.py
index a6de17f8cb55..3d75fa4c7d3f 100644
--- a/python/tvm/expr.py
+++ b/python/tvm/expr.py
@@ -1,3 +1,4 @@
+# pylint: disable=protected-access, no-member, missing-docstring
 from __future__ import absolute_import as _abs
 from ._ctypes._api import NodeBase, register_node
 from . import make as _make
@@ -174,7 +175,7 @@ class Call(Expr):
     Halide = 3
     Intrinsic = 4
     PureIntrinsic = 5
-    pass
+
 
 @register_node
 class Let(Expr):
diff --git a/python/tvm/function.py b/python/tvm/function.py
index 43e688276362..78491404d7b1 100644
--- a/python/tvm/function.py
+++ b/python/tvm/function.py
@@ -1,5 +1,8 @@
+# pylint: disable=protected-access, no-member, invalid-name
+# pylint: disable=redefined-builtin, undefined-variable
+"""Functions defined in TVM."""
 from __future__ import absolute_import as _abs
-from numbers import Number as _Number, Integral as _Integral
+from numbers import Integral as _Integral
 from ._ctypes._api import _init_function_module, convert
 from . import _function_internal
 from . import make as _make
@@ -8,6 +11,7 @@
 
 int32 = "int32"
 float32 = "float32"
+handle = "handle"
 
 def const(value, dtype=None):
     """construct a constant"""
@@ -65,7 +69,7 @@ def Var(name="tindex", dtype=int32):
     return _function_internal._Var(name, dtype)
 
 
-def placeholder(shape, dtype = None, name="placeholder"):
+def placeholder(shape, dtype=None, name="placeholder"):
     """Construct an empty tensor object.
 
     Parameters
@@ -84,6 +88,7 @@ def placeholder(shape, dtype = None, name="placeholder"):
     tensor: tensor.Tensor
         The created tensor
     """
+    shape = (shape,) if isinstance(shape, _expr.Expr) else shape
     dtype = float32 if dtype is None else dtype
     return _function_internal._Placeholder(
         shape, dtype, name)
@@ -111,8 +116,7 @@ def compute(shape, fcompute, name="compute"):
     tensor: tensor.Tensor
         The created tensor
     """
-    if isinstance(shape, _expr.Expr):
-        shape = (shape, )
+    shape = (shape,) if isinstance(shape, _expr.Expr) else shape
 
     ndim = len(shape)
     arg_names = fcompute.__code__.co_varnames
@@ -125,7 +129,44 @@ def compute(shape, fcompute, name="compute"):
     op_node = _function_internal._ComputeOp(
         name, dim_var, body)
     return _function_internal._Tensor(
-        shape, name, body.dtype, op_node, 0)
+        shape, body.dtype, op_node, 0)
+
+
+def Buffer(shape, dtype=None,
+           name="buffer", ptr=None,
+           strides=None):
+    """Create a new buffer
+
+    Parameters
+    ----------
+    shape : tuple of Expr
+        The shape of the buffer.
+
+    dtype : str, optional
+        The data type of the buffer.
+
+    name : str, optional
+        The name of the buffer.
+
+    ptr : Var, optional
+        The data pointer in the buffer.
+
+    strides: array of Expr
+        The stride of the buffer.
+
+    Returns
+    -------
+    buffer : Buffer
+        The created buffer
+    """
+    shape = (shape,) if isinstance(shape, _expr.Expr) else shape
+    dtype = float32 if dtype is None else dtype
+    strides = () if strides is None else strides
+    if ptr is None:
+        ptr = Var(name, "handle")
+
+    return _function_internal._Buffer(
+        name, ptr, shape, strides, dtype)
 
 
 def IterVar(dom, name='iter', thread_tag=''):
@@ -170,7 +211,7 @@ def sum(expr, rdom):
         The reduction domainx
     """
     rdom = rdom if isinstance(rdom, list) else [rdom]
-    x =  _make.Reduce("Add", expr, rdom)
+    x = _make.Reduce("Add", expr, rdom)
     return x
 
 
@@ -186,7 +227,7 @@ def min(expr, rdom):
         The reduction domainx
     """
     rdom = rdom if isinstance(rdom, list) else [rdom]
-    x =  _make.Reduce("Min", expr, rdom)
+    x = _make.Reduce("Min", expr, rdom)
     return x
 
 
@@ -202,7 +243,7 @@ def max(expr, rdom):
         The reduction domainx
     """
     rdom = rdom if isinstance(rdom, list) else [rdom]
-    x =  _make.Reduce("Max", expr, rdom)
+    x = _make.Reduce("Max", expr, rdom)
     return x
 
 
diff --git a/python/tvm/schedule.py b/python/tvm/schedule.py
index 7a5282b1219f..a8ecb97bf27b 100644
--- a/python/tvm/schedule.py
+++ b/python/tvm/schedule.py
@@ -1,3 +1,4 @@
+# pylint: disable=protected-access, no-member
 """Collection structure in the high level DSL."""
 from __future__ import absolute_import as _abs
 from ._ctypes._api import NodeBase, register_node
@@ -6,15 +7,18 @@
 
 @register_node
 class Split(NodeBase):
+    """Split operation on axis."""
     pass
 
 @register_node
 class Fuse(NodeBase):
+    """Fuse operation on axis."""
     pass
 
 
 @register_node
 class Schedule(NodeBase):
+    """Schedule for all the stages."""
     def __getitem__(self, k):
         if isinstance(k, _tensor.Tensor):
             k = k.op
@@ -26,6 +30,7 @@ def __getitem__(self, k):
 
 @register_node
 class Stage(NodeBase):
+    """A Stage represents schedule for one operation."""
     def split(self, parent, factor=None, outer=None):
         """Split the stage either by factor providing outer scope, or both
 
@@ -132,6 +137,32 @@ def reorder(self, *args):
         _function_internal._StageReorder(self, args)
 
     def tile(self, x_parent, y_parent, x_factor, y_factor):
+        """ Perform tiling on two dimensions
+
+        The final loop order from outmost to inner most are
+        [x_outer, y_outer, x_inner, y_inner]
+
+        Parameters
+        ----------
+        x_parent : IterVar
+            The original x dimension
+        y_parent : IterVar
+            The original y dimension
+        x_factor : Expr
+            The stride factor on x axis
+        y_factor : Expr The stride factor on y axis
+
+        Returns
+        -------
+        x_outer : IterVar
+            Outer axis of x dimension
+        y_outer : IterVar
+            Outer axis of y dimension
+        x_inner : IterVar
+            Inner axis of x dimension
+        p_y_inner : IterVar
+            Inner axis of y dimension
+        """
         x_outer, y_outer, x_inner, y_inner = _function_internal._StageTile(
             self, x_parent, y_parent, x_factor, y_factor)
         return x_outer, y_outer, x_inner, y_inner
diff --git a/python/tvm/stmt.py b/python/tvm/stmt.py
index cc22e168782a..97ef3b6b3c8c 100644
--- a/python/tvm/stmt.py
+++ b/python/tvm/stmt.py
@@ -1,6 +1,6 @@
+# pylint: disable=protected-access, no-member, missing-docstring
 from __future__ import absolute_import as _abs
 from ._ctypes._api import NodeBase, register_node
-from . import make as _make
 
 class Stmt(NodeBase):
     pass
@@ -23,7 +23,6 @@ class For(Stmt):
     Parallel = 1
     Vectorized = 2
     Unrolled = 3
-    pass
 
 @register_node
 class Store(Stmt):
diff --git a/python/tvm/tensor.py b/python/tvm/tensor.py
index 99e14180aa7b..fdaec1d33c25 100644
--- a/python/tvm/tensor.py
+++ b/python/tvm/tensor.py
@@ -1,3 +1,5 @@
+# pylint: disable=protected-access, no-member, invalid-name
+"""Tensor related abstractions"""
 from __future__ import absolute_import as _abs
 from ._ctypes._api import NodeBase, SliceBase, register_node, convert
 from . import collections as _collections
@@ -51,10 +53,12 @@ def __eq__(self, other):
 
     @property
     def ndim(self):
+        """Dimension of the tensor."""
         return len(self.shape)
 
 
 class Operation(NodeBase):
+    """Represent an operation that generate a tensor"""
     def output(self, index):
         """Get the index-th output of the operation
 
@@ -72,8 +76,10 @@ def output(self, index):
 
 @register_node
 class ComputeOp(Operation):
+    """Compute operation."""
     pass
 
 @register_node
 class PlaceholderOp(Operation):
+    """Placeholder operation."""
     pass
diff --git a/src/base/common.h b/src/base/common.h
index 66ffffef5cc2..0485bdfc4af0 100644
--- a/src/base/common.h
+++ b/src/base/common.h
@@ -12,6 +12,7 @@
 namespace tvm {
 
 inline std::string Type2String(const Type& t) {
+  if (t.code()  ==Type::Handle) return "handle";
   std::ostringstream os;
   os << t;
   return os.str();
@@ -28,6 +29,8 @@ inline Type String2Type(std::string s) {
     code = Type::Float; s = s.substr(5);
   } else if (s.substr(0, 5) == "float") {
     code = Type::Float; s = s.substr(5);
+  } else if (s == "handle") {
+    return Type(Type::Handle, 0, 0);
   } else {
     LOG(FATAL) << "unknown type " << s;
   }
diff --git a/src/c_api/c_api_ir.cc b/src/c_api/c_api_ir.cc
index af66e9db6690..c2110c76d9f6 100644
--- a/src/c_api/c_api_ir.cc
+++ b/src/c_api/c_api_ir.cc
@@ -123,6 +123,7 @@ REGISTER_MAKE3(Let);
 REGISTER_MAKE3(LetStmt);
 REGISTER_MAKE2(AssertStmt);
 REGISTER_MAKE3(ProducerConsumer);
+REGISTER_MAKE3(Load);
 REGISTER_MAKE3(Store);
 REGISTER_MAKE4(Provide);
 REGISTER_MAKE1(Free);
diff --git a/src/c_api/c_api_lang.cc b/src/c_api/c_api_lang.cc
index 3f2b4e2a0abd..948783966dfd 100644
--- a/src/c_api/c_api_lang.cc
+++ b/src/c_api/c_api_lang.cc
@@ -5,6 +5,7 @@
  */
 #include <tvm/expr.h>
 #include <tvm/tensor.h>
+#include <tvm/buffer.h>
 #include <tvm/schedule.h>
 #include "./c_api_registry.h"
 
@@ -140,14 +141,23 @@ TVM_REGISTER_API(Range)
 .add_argument("begin", "Expr", "beginning of the range.")
 .add_argument("end", "Expr", "extent of the range");
 
-TVM_REGISTER_API(_Tensor)
+TVM_REGISTER_API(_Buffer)
 .set_body([](const ArgStack& args,  RetValue *ret) {
-    *ret = TensorNode::make(args.at(0),
+    *ret = BufferNode::make(args.at(0),
+                            args.at(1),
                             args.at(2),
                             args.at(3),
                             args.at(4));
   });
 
+TVM_REGISTER_API(_Tensor)
+.set_body([](const ArgStack& args,  RetValue *ret) {
+    *ret = TensorNode::make(args.at(0),
+                            args.at(1),
+                            args.at(2),
+                            args.at(3));
+  });
+
 TVM_REGISTER_API(_TensorEqual)
 .set_body([](const ArgStack& args,  RetValue *ret) {
     *ret = args.at(0).operator Tensor() == args.at(1).operator Tensor();
diff --git a/src/lang/buffer.cc b/src/lang/buffer.cc
new file mode 100644
index 000000000000..02cd05224e53
--- /dev/null
+++ b/src/lang/buffer.cc
@@ -0,0 +1,78 @@
+/*!
+ *  Copyright (c) 2016 by Contributors
+ * \file buffer.cc
+ */
+#include <tvm/buffer.h>
+#include <tvm/ir.h>
+
+namespace tvm {
+
+Array<Expr> GetStrides(Array<Expr> shape) {
+  CHECK_NE(shape.size(), 0U);
+  std::vector<Expr> vec{make_const(shape[0].type(), 1)};
+  for (size_t i = shape.size() - 1; i != 0; --i) {
+    vec.push_back(shape[i - 1] * vec.back());
+  }
+  return Array<Expr>(vec.rbegin(), vec.rend());
+}
+
+Buffer::Buffer(Array<Expr> shape,
+               Type dtype,
+               std::string name)
+    : Buffer(BufferNode::make(
+          name,
+          Var(name, Type(Type::Handle, 0, 0)),
+          shape, Array<Expr>(), dtype)) {
+}
+
+inline Expr BufferOffset(const BufferNode* n, Array<Expr> index) {
+  Expr base;
+  if (n->strides.size() == 0) {
+    CHECK_EQ(n->shape.size(), index.size());
+    base = index[0];
+    for (size_t i = 1; i < index.size(); ++i) {
+      base = base * n->shape[i] + index[i];
+    }
+  } else {
+    CHECK_EQ(n->strides.size(), index.size());
+    base = index[0] * n->strides[0];
+    for (size_t i = 1; i < index.size(); ++i) {
+      base = base + index[i] * n->strides[i];
+    }
+  }
+  return base;
+}
+
+Expr Buffer::MakeLoad(Array<Expr> index) const {
+  const BufferNode* n = operator->();
+  return ir::Load::make(n->dtype, n->ptr, BufferOffset(n, index));
+}
+
+Stmt Buffer::MakeStore(Array<Expr> index, Expr value) const {
+  const BufferNode* n = operator->();
+  CHECK_EQ(value.type(), n->dtype);
+  return ir::Store::make(n->ptr, BufferOffset(n, index), value);
+}
+
+Buffer BufferNode::make(std::string name,
+                        Var ptr,
+                        Array<Expr> shape,
+                        Array<Expr> strides,
+                        Type dtype) {
+  auto n = std::make_shared<BufferNode>();
+  n->name = name;
+  n->ptr = ptr;
+  n->shape = shape;
+  n->strides = strides;
+  n->dtype = dtype;
+  return Buffer(n);
+}
+
+TVM_STATIC_IR_FUNCTOR(IRPrinter, vtable)
+.set_dispatch<BufferNode>([](const BufferNode *op, IRPrinter *p) {
+    p->stream << "buffer(" << op->name << ", " << op << ")";
+});
+
+TVM_REGISTER_NODE_TYPE(BufferNode);
+
+}  // namespace tvm
diff --git a/src/lang/operation.cc b/src/lang/operation.cc
index 1883a5eacff3..ce26e65da8fe 100644
--- a/src/lang/operation.cc
+++ b/src/lang/operation.cc
@@ -1,4 +1,3 @@
-
 /*!
  *  Copyright (c) 2016 by Contributors
  * \file operation.cc
diff --git a/src/pass/inline.cc b/src/pass/inline.cc
index b912e30897db..085fe738eaeb 100644
--- a/src/pass/inline.cc
+++ b/src/pass/inline.cc
@@ -8,7 +8,6 @@
 
 namespace tvm {
 namespace ir {
-namespace {
 
 // inliner to inline a function
 // the result may not be SSA,
@@ -50,12 +49,10 @@ class IRInline : public IRMutator {
   }
 };
 
-}  // namespace
-
-Stmt Inline(FunctionRef f,
+Stmt Inline(Stmt stmt,
+            FunctionRef f,
             Array<Var> args,
-            Expr body,
-            Stmt stmt) {
+            Expr body) {
   CHECK_EQ(f->num_outputs(), 1)
       << "can only inline output single value operation";
   return ConvertSSA(IRInline(f, args, body).Mutate(stmt));
diff --git a/src/pass/schedule_ops.cc b/src/pass/schedule_ops.cc
index 3cdb8f171a7f..a62cf678b8cf 100644
--- a/src/pass/schedule_ops.cc
+++ b/src/pass/schedule_ops.cc
@@ -13,7 +13,6 @@
 
 namespace tvm {
 namespace ir {
-namespace {
 
 /*!
  * \brief use message passing to calculate the assignment of each Var inside the loop body.
@@ -256,7 +255,7 @@ Stmt MakePipeline(const Stage& sch,
   if (sch->op.as<ComputeOpNode>()) {
     provide = MakeProvide(sch->op.as<ComputeOpNode>(), tensors);
   } else {
-    LOG(FATAL) << "not supported op";
+    LOG(FATAL) << "not supported op " << sch->op->type_key();
   }
   std::vector<std::vector<Stmt> > nest = MakeLoopNest(sch, dom_map);
   Stmt producer = MergeNest(nest, provide);
@@ -317,10 +316,9 @@ Stmt InjectInline(const Operation op, Stmt body) {
   for (auto iv : compute->axis) {
     args.push_back(iv->var);
   }
-  return Inline(op, args, compute->body, body);
+  return Inline(body, op, args, compute->body);
 }
 
-}  // namespace
 
 Stmt ScheduleOps(
     Schedule sch, Map<IterVar, Range> dom_map) {
@@ -328,6 +326,8 @@ Stmt ScheduleOps(
   // reverse the post DFS order.
   for (size_t i = sch->stages.size(); i != 0; --i) {
     Stage s = sch->stages[i - 1];
+    // no need to specify place holder op.
+    if (s->op.as<PlaceholderOpNode>()) continue;
     if (s->attach_type == kInline) {
       body = InjectInline(s->op, body);
     } else if (s->attach_type == kRoot || s-> attach_type == kNone) {
diff --git a/src/schedule/bound.cc b/src/schedule/bound.cc
index 9ac720305590..6a23f48d8c90 100644
--- a/src/schedule/bound.cc
+++ b/src/schedule/bound.cc
@@ -151,8 +151,10 @@ BoundProp(const Array<Operation>& post_order,
         }
       };
       ir::PostOrderVisit(op.as<ComputeOpNode>()->body, fvisit);
+    } else if (op.as<PlaceholderOpNode>()) {
+      // do nothing
     } else {
-      LOG(FATAL) << "unknown operation mode";
+      LOG(FATAL) << "unknown operation mode " << op->type_key();
     }
   }
   return result;
diff --git a/src/schedule/graph.cc b/src/schedule/graph.cc
index 5b13c1569078..530eecaac971 100644
--- a/src/schedule/graph.cc
+++ b/src/schedule/graph.cc
@@ -42,10 +42,11 @@ ReadGraph CreateReadGraph(const Array<Operation>& roots) {
       };
       ir::PostOrderVisit(op.as<ComputeOpNode>()->body, fvisit);
       rmap.Set(op, deps);
+    } else if (op.as<PlaceholderOpNode>()) {
+      // empty set of deps
+      rmap.Set(op, deps);
     } else {
-      if (!op.as<PlaceholderOpNode>()) {
-        LOG(FATAL) << "unknown Operation" << op->type_key();
-      }
+      LOG(FATAL) << "unknown Operation" << op->type_key();
     }
   }
   return rmap;
@@ -56,7 +57,7 @@ void PostDFSOrder(const Operation& op,
                   const ReadGraph& g,
                   std::unordered_set<Operation>* visited,
                   Array<Operation>* post_order) {
-  if (op.as<PlaceholderOpNode>() || visited->count(op)) return;
+  if (visited->count(op)) return;
   visited->insert(op);
   for (const auto& t : g.at(op)) {
     PostDFSOrder(t->op, g, visited, post_order);
diff --git a/tests/python/test_lang_buffer.py b/tests/python/test_lang_buffer.py
new file mode 100644
index 000000000000..b1b6b7d9b8fb
--- /dev/null
+++ b/tests/python/test_lang_buffer.py
@@ -0,0 +1,16 @@
+import tvm
+
+def test_buffer():
+    m = tvm.Var('m')
+    n = tvm.Var('n')
+    l = tvm.Var('l')
+    Ab = tvm.Buffer((m, n), tvm.float32)
+    Bb = tvm.Buffer((n, l), tvm.float32)
+
+    assert isinstance(Ab, tvm.collections.Buffer)
+    assert Ab.dtype == tvm.float32
+    assert tuple(Ab.shape) == (m, n)
+
+
+if __name__ == "__main__":
+    test_buffer()
diff --git a/tests/python/test_lang_tensor.py b/tests/python/test_lang_tensor.py
index af0632866404..01ab5109f628 100644
--- a/tests/python/test_lang_tensor.py
+++ b/tests/python/test_lang_tensor.py
@@ -33,6 +33,7 @@ def test_tensor_reduce():
     assert(isinstance(C_loaded, tvm.tensor.Tensor))
     assert(str(C_loaded) == str(C))
 
+
 if __name__ == "__main__":
     test_tensor()
     test_tensor_reduce()
diff --git a/tests/python/test_pass_inline.py b/tests/python/test_pass_inline.py
index 858864c60b75..43149fd3d966 100644
--- a/tests/python/test_pass_inline.py
+++ b/tests/python/test_pass_inline.py
@@ -6,7 +6,7 @@ def test_inline():
     T = tvm.compute((m,), lambda i,: A[i] + 10, name='T')
     stmt = tvm.make.Evaluate(T[10] + 11 * T[100])
     stmt = tvm.ir_pass.Inline(
-        T.op, [x.var for x in T.op.axis], T.op.body, stmt)
+        stmt, T.op, [x.var for x in T.op.axis], T.op.body)
     print(stmt)
     assert(tvm.ir_pass.VerifySSA(stmt))
 
diff --git a/tests/python/test_schedule_bound_inference.py b/tests/python/test_schedule_bound_inference.py
index 9e8c70cac66b..e80fb275c561 100644
--- a/tests/python/test_schedule_bound_inference.py
+++ b/tests/python/test_schedule_bound_inference.py
@@ -63,8 +63,8 @@ def test_create_read_graph():
     assert g[A2.op][0] == A1
     assert g[A1.op][0] == A
     post_order = tvm.schedule.PostDFSOrder([A2.op], g)
-    assert(post_order[0] == A1.op)
-    assert(post_order[1] == A2.op)
+    assert(post_order[0] == A.op)
+    assert(post_order[1] == A1.op)
 
 
 if __name__ == "__main__":