* add support to gcc8, add docker env test=develop

* Add multihead fuse pass for ernie opt

* Refine softmax

test=develop

* Refine cuda kernel

* Refine cuda version

* Refine cmake

test=develop

* refine header file

* refine test case and pass
* refine comments

* Add ConvTranspose + BatchNorm fuse pass
test=develop

* Add tests for conv+bn and conv_transpose+bn passes
test=develop

* Follow Wangzhen's comment in PR 18970, test=develop

* Review comments, test=develop

* Leave fake quantization around mul

test=develop

* Replace Fake with Real Quantized Mul

test=develop

* Fix bug in quantize placement pass

Nodes in the graph now have checked type instead of node name when they are to be marked for quantization test=develop

* Fix conv2d+dequantize squash for residual fusion

test=develop

* Disable conv-requant squash

test=develop

* codegen code for reconstruction test=develop

* fix the cmake test=develop

* fix review advice test=develop

Add dtype for coalesce_tensor_op

* Fix conv2d+dequantize squash for residual fusion

test=develop

* Change condition

test=develop

* Add fc_elementwise_layernorm_fuse pass and unittest.

* Add fused_fc_elementwise_layernorm op and its GPU kernel.
test=develop

* Apply fc_elementwise_layernorm_fuse_pass to GPU inference.

* Add the setting of attrs in the definition of binary_op.
test=develop

* Add comment.

* Implement the unittest.
test=develop

* Change the unittest name of layer_norm.
test=develop

* fix memory reuse bug on feeding variables, test=develop

* add comments to reference count members, test=develop

* fix warning info
test=develop

* fix bug of all_reduce_deps_pass
test=develop

* Refine the codes related to fc op.

* Add GPU implementation for fc functor.

* Apply fc_fuse_pass in GPU inference.
test=develop

* Change the cmake for fc op.

* Change PADDLE_ENFORCE to PADDLE_ENFORCE_EQ.

* Add an attribute to set the activation type in fc_op.

* Enhance the unittest of fc_op.
test=develop

* Remove the declaration of FCOpGrad back to the header file.
test=develop

* Set default value for newly added arguments in test_fc_op.
test=develop

* Enhance fc_fuse_pass to enable fusing relu.

* Allow print the shapes of var_desc in graph.
test=develop

* Enhance fc_fuse_pass_tester.

* Remove the use of PADDLE_ENFORCE.
test=develop

* Correct the number of ops after fusing.
test=develop

* Fix a typo.
test=develop

* Set activation_type to null when there is no relu in fc.
test=develop

* Refine fc_fuse_pass's codes.

* Enable the set of shape for tensor.

* Refine repeated_fc_relu_pass and add unittest.
test=develop

* Open fuse all reduce op
test=develop

* Add Fuse optimization op log

* Add log in fuse_optimizer op pass and fuse all_reduce op pass

* replace with boost::optional<bool>
test=develop

* Polish code
test=develop

* fix code coverage
test=develop

* fix vlog level and fuse option type
test=develop

* Refine the codes related to fc op.

* Add GPU implementation for fc functor.

* Apply fc_fuse_pass in GPU inference.
test=develop

* Change the cmake for fc op.

* Change PADDLE_ENFORCE to PADDLE_ENFORCE_EQ.

* Add an attribute to set the activation type in fc_op.

* Enhance the unittest of fc_op.
test=develop

* Remove the declaration of FCOpGrad back to the header file.
test=develop

* Set default value for newly added arguments in test_fc_op.
test=develop

* Enable fused_all_reduce_op_handle support GPU and CPU Gradients

* test=develop codegen for fused elementwise operation

* fix test=develop

* enable ngraph throught build_strategy test=develop

* add unittest test=develop

* put use_ngraph unconditional test=develop

* remove paddle_enforce test=develop

* remove paddle_enforce test=develop

* fix copyright test=develop

* limit for ngraph only test=develop

test=develop

* Add a interface to enable cudnn for inference.

* Add cudnn_placement_pass.
test=develop

* Set the default value of cudnn_enabled_op_types to null.
test=develop

* Write the common basic class, placement_pass_base, to refine the codes.
test=develop

* Call EnableCUDNN in unittest.
test=develop

* Refine cudnn_placement_pass tester.

* Enable the testing of cudnn_placement_pass in inference's unittest.
test=develop

* Add the check of op kernels.
test=develop

* Add simplify_with_basic_ops_pass to replace dropout_op with scale_op when is_test is true.
test=develop

* Delete dropout_op directly when upscale_in_train is true.
test=develop

* Improve the debug string, adding the print of op_desc information.

* Fix the case when dropout's input x is reused as the next op's output.

* Add the pass to inference.
test=develop

* Change the log level.
test=develop

* Add unittest for inplace case.

* Add comment to explain the pass.

* Apply the pass for CPU inference.
test=develop

* Fix the typo.
test=develop

* Add the check of AttrType.
test=develop

* fix correctness of the communicator

* fix a bug in send thread when sending var context is empty, test=develop

* add lookup_table_prefetch_op and prefetch optimize, test=develop

* remove remote prefetch GPU supported

* word2vec force with CPU, test=develop

* test dist remote lookup table force with CPU, test=develop

test=develop

* Add generalized Conv+Activation MKLDNN fuse pass creation Part2
test=develop

* Undefined behaviour of GetAttrIfExists<> FIX
test=develop

* fix mask rcnn bug:
1. affine channel fuse (diff)
2. condition block op (memory leak)
3. merge lod tensor op (diff)
4. memroy optim (diff)
test=develop

* fix ci aboud PADDLE_ENFOCE
fix merge lod infer op ut
test=develop

* fix compilation issue in windows vs2017, test=develop

* fix gtest lib not found issue, test=develop

remove the warning for reminding user to avoid using the OriginProgram method, test=develop (#19244)

This log information may annoy users who don't need to care about it.

test=develop

* Add requantize squash

test=develop

* Add more precise tests
test=develop

* REname and REfactor tester

test=develop

test=develop

test=develop

* Enhance fuse optimization op pass
test=develop

* open gc by default, test=develop

* fix test_train_recognize_digits and disable gc when ngraph is enabled, test=develop

* fix conditional_block op eager deletion bug, test=develop

* add some comments to reviewers, test=develop