eliminate pnnx dropout

tools/pnnx/src/CMakeLists.txt

@@ -208,6 +208,7 @@ set(pnnx_pass_level4_SRCS
 )
 
 set(pnnx_pass_level5_SRCS
+    pass_level5/eliminate_dropout.cpp
     pass_level5/eliminate_maxpool_indices.cpp
     pass_level5/eliminate_slice.cpp
     pass_level5/eliminate_view_reshape.cpp
@@ -251,7 +252,7 @@ set(pnnx_pass_ncnn_SRCS
     pass_ncnn/F_adaptive_max_pool1d.cpp
     pass_ncnn/F_adaptive_max_pool2d.cpp
     pass_ncnn/F_adaptive_max_pool3d.cpp
-    pass_ncnn/F_alpha_dropout.cpp
+    #pass_ncnn/F_alpha_dropout.cpp
     pass_ncnn/F_avg_pool1d.cpp
     pass_ncnn/F_avg_pool2d.cpp
     pass_ncnn/F_avg_pool3d.cpp
@@ -260,12 +261,12 @@ set(pnnx_pass_ncnn_SRCS
     pass_ncnn/F_conv1d.cpp
     pass_ncnn/F_conv2d.cpp
     pass_ncnn/F_conv3d.cpp
-    pass_ncnn/F_dropout.cpp
-    pass_ncnn/F_dropout2d.cpp
-    pass_ncnn/F_dropout3d.cpp
+    #pass_ncnn/F_dropout.cpp
+    #pass_ncnn/F_dropout2d.cpp
+    #pass_ncnn/F_dropout3d.cpp
     pass_ncnn/F_elu.cpp
     pass_ncnn/F_embedding.cpp
-    pass_ncnn/F_feature_alpha_dropout.cpp
+    #pass_ncnn/F_feature_alpha_dropout.cpp
     pass_ncnn/F_gelu.cpp
     pass_ncnn/F_group_norm.cpp
     pass_ncnn/F_hardsigmoid.cpp
@@ -302,7 +303,7 @@ set(pnnx_pass_ncnn_SRCS
     pass_ncnn/nn_AdaptiveMaxPool1d.cpp
     pass_ncnn/nn_AdaptiveMaxPool2d.cpp
     pass_ncnn/nn_AdaptiveMaxPool3d.cpp
-    pass_ncnn/nn_AlphaDropout.cpp
+    #pass_ncnn/nn_AlphaDropout.cpp
     pass_ncnn/nn_AvgPool1d.cpp
     pass_ncnn/nn_AvgPool2d.cpp
     pass_ncnn/nn_AvgPool3d.cpp
@@ -317,9 +318,9 @@ set(pnnx_pass_ncnn_SRCS
     pass_ncnn/nn_Conv2d.cpp
     pass_ncnn/nn_Conv3d.cpp
     pass_ncnn/nn_ConvTranspose2d.cpp
-    pass_ncnn/nn_Dropout.cpp
-    pass_ncnn/nn_Dropout2d.cpp
-    pass_ncnn/nn_Dropout3d.cpp
+    #pass_ncnn/nn_Dropout.cpp
+    #pass_ncnn/nn_Dropout2d.cpp
+    #pass_ncnn/nn_Dropout3d.cpp
     pass_ncnn/nn_ELU.cpp
     pass_ncnn/nn_Embedding.cpp
     pass_ncnn/nn_GELU.cpp

tools/pnnx/src/pass_level5.cpp

@@ -14,6 +14,7 @@
 
 #include "pass_level5.h"
 
+#include "pass_level5/eliminate_dropout.h"
 #include "pass_level5/eliminate_slice.h"
 #include "pass_level5/eliminate_view_reshape.h"
 #include "pass_level5/eval_expression.h"
@@ -49,6 +50,8 @@ void pass_level5(Graph& g)
 
     eliminate_view_reshape(g);
 
+    eliminate_dropout(g);
+
     fuse_channel_shuffle(g);
 
     dead_code_elimination(g);

tools/pnnx/src/pass_level5/eliminate_dropout.cpp

@@ -0,0 +1,76 @@
+// Tencent is pleased to support the open source community by making ncnn available.
+//
+// Copyright (C) 2021 THL A29 Limited, a Tencent company. All rights reserved.
+//
+// Licensed under the BSD 3-Clause License (the "License"); you may not use this file except
+// in compliance with the License. You may obtain a copy of the License at
+//
+// https://opensource.org/licenses/BSD-3-Clause
+//
+// 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.
+
+#include "eliminate_dropout.h"
+
+#include <algorithm>
+#include "pass_level2.h"
+
+namespace pnnx {
+
+void eliminate_dropout(Graph& graph)
+{
+    while (1)
+    {
+        bool matched = false;
+
+        for (size_t i = 0; i < graph.ops.size(); i++)
+        {
+            Operator* op = graph.ops[i];
+
+            if (op->type != "F.alpha_dropout" && op->type != "F.dropout" && op->type != "F.dropout2d" && op->type != "F.dropout3d" && op->type != "F.feature_alpha_dropout" && op->type != "nn.AlphaDropout" && op->type != "nn.Dropout" && op->type != "nn.Dropout2d" && op->type != "nn.Dropout3d")
+                continue;
+
+            // delete noop-like dropout
+            matched = true;
+
+            for (auto& x : op->inputs)
+            {
+                x->remove_consumer(op);
+            }
+
+            Operand* slice_out = op->outputs[0];
+
+            for (auto& x : slice_out->consumers)
+            {
+                for (size_t j = 0; j < x->inputs.size(); j++)
+                {
+                    if (x->inputs[j] == slice_out)
+                        x->inputs[j] = op->inputs[0];
+                }
+
+                op->inputs[0]->consumers.push_back(x);
+            }
+
+            slice_out->producer = 0;
+            slice_out->consumers.clear();
+
+            graph.operands.erase(std::find(graph.operands.begin(), graph.operands.end(), slice_out));
+            delete slice_out;
+
+            op->inputs.clear();
+            op->outputs.clear();
+
+            graph.ops.erase(graph.ops.begin() + i);
+            delete op;
+
+            break;
+        }
+
+        if (!matched)
+            break;
+    }
+}
+
+} // namespace pnnx

tools/pnnx/src/pass_ncnn/nn_Dropout.cpp → tools/pnnx/src/pass_level5/eliminate_dropout.h

@@ -12,38 +12,10 @@
 // CONDITIONS OF ANY KIND, either express or implied. See the License for the
 // specific language governing permissions and limitations under the License.
 
-#include "pass_ncnn.h"
+#include "ir.h"
 
 namespace pnnx {
 
-namespace ncnn {
-
-class nn_Dropout : public GraphRewriterPass
-{
-public:
-    const char* match_pattern_graph() const
-    {
-        return R"PNNXIR(7767517
-3 2
-pnnx.Input              input       0 1 input
-nn.Dropout              op_0        1 1 input out
-pnnx.Output             output      1 0 out
-)PNNXIR";
-    }
-
-    const char* type_str() const
-    {
-        return "Noop";
-    }
-
-    const char* name_str() const
-    {
-        return "dropout";
-    }
-};
-
-REGISTER_GLOBAL_PNNX_NCNN_GRAPH_REWRITER_PASS(nn_Dropout, 20)
-
-} // namespace ncnn
+void eliminate_dropout(Graph& graph);
 
 } // namespace pnnx