The fixed bugs:

1. The condition sub-graph is not pruned
2. When backward graph is extremely simple, the whole backward ops are pruned.

* fix compiled error of butil when with_pslib=on and with_testing=on
* test=develop

* fc-dequantize squash
test=develop

* change according to reviews
test=develop

* change PADDLE_ENFORCE
test=develop

* add second test when fc-dequant do not fuse
test=develop

* change all related PADDLE_ENFORCE
test=develop

* Add reshape int8 op

test=develop

* Change test to CPUPlace

test=develop

* Correct tests

test=develop

* add fake init for the trainer, fix large memory hold in the trainer
* do not merge recv vars from a remote endpoint, test=develop
* add recv and save op, merge slice var in one op, save memory
* remove hsigmoid with pull sparse, test=develop

* make OperatorWithKernel::InferShape virtual, test=develop

* fix test_prepare_op by relu, test=develop

* MKLDNN v1.0 rebase to Paddle 1.6
test=develop

* Add hacky paddle::string::to_string() implementation

* vectorize<int64-t>() -> vectorize() cleanup
test=develop

* PADDLE_ENFORCE and void_cast fixes
test=develop

* Rebase changes
test=develop

* Cosmetics
test=develop

* Delete MKL from mkldnn.cmake
test=develop

* CMake debug commands
test=develop

* Delete MKLDNN_VERBOSE and rebase fixes
test=develop

* Rebase fixes
test=develop

* Temporarily disable int8 resnet101 vgg16 and vgg19 tests
test=develop

* Add libmkldnn.so.1 to python setup
test=develop

* Add libmkldnn.so.1 to inference_lib cmake after rebase
test=develop

* Post rebase fixes + FC int8 changes
test=develop

* Fix LRN NHWC
test=develop

* Fix NHWC conv3d
test=develop

* Windows build fix + next conv3d fix
test=develop

* Fix conv2d on AVX2 machines
test=develop

* fix master patch when slot is dense
* test=develop

* fix code style of fleet_wrapper
* test=develop

* remove optimize_for in framework.proto
* test=develop

* polish infer shape registry, test=develop

* modify some operators registry, test=develop

* Add a single_process_multi_thread transpiler.
* Add some UTs.
* Fix some API description.

* add file check_op_desc.py and add interface to get default value. test=develop

* add test for c++ coverage rate. test=develop

* Correct typo. test=develop

* make DisableGlogInfo able to mute all logs in inference. 

* add jeston compile support
test=develop

* refine the cmake
test=develop

* fix -Wno-error=sign-compare warning in gcc8

test=develop

* fix warning in distributed codes

test=develop

* add unused input vars check for OpWithKernel, test=develop

* remove unused vars in some ops, test=develop

* fix batch_norm, test=develop

* add white list, test=develop

* add CI check for white list, test=develop

* :ove white list to c++, test=develop

* solve failure of CI, test=develop

* add unittest for unused_var_check, test=develop

* refine code, enable check in operator_test, test=develop

* skip mkldnn, test=develop

* extend white list, test=develop

* refine condition of mkldnn, test=develop

* fix paddle_build, test=develop

* follow comments, test=develop

* fix GetExpectedKernelType

* add wiki ref to err_msg, test=develop

* follow comment, test=develop

* Commit before merging develop

test=develop

* Backup after working with Huihuang logs

* Commit before deleting Huihuang debug loggings

* Commit before debug

test=develop

* Fix bug commit

test=develop

* Backup of fixing bugs

test=develop

* Clean up code

test=develop

* Fix a bug in sum_op

test=develop

* add_dygraph_execution_context

* add dygraph infershape context and execution context; test=develop

* fix imperative bug; test=develop

* remove inputs outputs interface from execution context,
because it have same function with inputNames;
test=develop

* remove tracer_test ctest; test=develop

* fix split op bug; test=develop

* fix unitests bug; test=develop

* fix distribute test bug; test=develop

* fix ngraph compile bug; test=develop

* fix grad maker bug; test=develop

* fix load op bugs; test=develop

* fix operator.cc construct bug; test=develop

* remove useless name find in operator; test=develop

* add tracer_test; test=develop

* fix concat, split bug; test=develop

* remove tracer_test unitest; test=develop

* fix attribute check bug; test=develop

* add test code to fix converage; test=develop

* remove useless code, change check backward input in engin; test=develop

* unlock var type infer shape;test=develop

* add ShareAllLoD api; test=develop

* add dygraph infershape context unitest; test=develop

* remove increase and decrease lod in dygraph; test=develop

* addd override; test=develop

* fix increase descrease lod; test=develop

* fix paddle_enforce; test=develop

* disable lod op dygraph check; test=develop

* fix paddle enforce error; test=develop

* add comment for op_registry and OperatorBase; test=develop

* optimize the comment of op_registry; test=develop

* fix format of comment; test=develop

* fix format of comment; test=develop

* optimize the format of comment; test=develop

* optimize the format of the comment; test=develop

* optimize comment of op_registry; test=develop

* use system allocator in unittests, test=develop

* fix op bugs, test=develop

* fix tensor copy bug when src and dst are the same, test=develop

* remove -Wno-error=sign-compare, make warning as error

test=develop test=document_fix

* fix exist compile warning

test=develop

* fix ref_cnt pass, test=develop

* add cpp unittests to reference_count_pass, test=develop

* follow comments, test=develop

* add numpy bridge

* fix template compile

* add unittest, add default
test=develop

* fix unittest
test=develop

* fix unittest
test=develop

* zero_copy=True for to_variable,
test=develop

* bug fix
test=develop

* disable deprecated NumPy API
test=develop

* use better design of NumpyAllocator
test=develop

* fix Py_None check
test=develop

* reset c++ tracer when jump out dygraph guard
test=develop

* refine PADDLE_ENFORCE_xx format
test=develop

* bug fix of tracer switch
test=develop

* update decref
test=develop

test=develop

* Implement Int8 FC

* Integrate FC into INT8v2

test=develop

* int8 FC: transpose weights before computing scales

test=develop

* Add support for activation_type string in FC

test=develop

* Disable MKL-DNN's FC in VGG16 and 19

test=develop

* Disable FC quantization when mkldnn FC is disabled

test=develop

* Solve PADDLE_ENFORCES in FC int8

* Fix Paddle enforces and remove const cast

test=develop

* Fix style changes

test=develop

* Fix quantizer_tester test and add fc quantization

test=develop

* Fix FC test fail on CUDA

* Remove unnecessary log from quantize placement pass

test=develop

* Add Thread ID to FC hash key

test=develop

* Add comments to MKL-DNN FC Kernel

test=develop

* Refactor quantizer

test=develop

* Fix linter issues

test=develop

* Fix crash in slim googlenet

test=develop

* Fix PADDLE_ENFORCE messages

test=develop

* Add fc padding to solve mkl performance
test=develop

* fix gpu pass and error information
test=develop

* fix fc_fuse_pass_test
test=develop

* fix error information
test=develop

* fix error information
test=develop

* fix name and add fc op padding test
test=develop

* fix attributes
test=develop

* optimize fc padding
test=develop

* fix test
test=develop

* print table stat
test=develop

* notes
test=develop

* notes
test=develop

* fix fetch handler problem and refactor
when a user define FetchHandler class, he or she should initialize a handler
with variable dict. the key of a variable dict is a user defined name,
the value of a variable dict is a Varaible generated from python API.

For each fetching, a user should implement handler function in which
fetched_result_dict will be available and the user can access the fetched value
with user defined keys.

* Disable fusion_group pass for windows and mac. We will do some experiments on Linux first.
test=develop

* Print the subgraph when check failed.
test=develop

* polish code details, test=develop

* futher polish hint msg, test=develop