File size: 2,690 Bytes
be903e2 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 | // 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 "dead_code_elimination.h"
namespace pnnx {
void dead_code_elimination(Graph& graph)
{
// dead op elimination
for (;;)
{
bool need_eliminate = false;
for (int i = (int)graph.ops.size() - 1; i >= 0; i--)
{
Operator* op = graph.ops[i];
if (op->type == "pnnx.Output")
continue;
int consumers = 0;
for (const Operand* operand : op->outputs)
{
consumers += (int)operand->consumers.size();
}
if (consumers == 0)
{
need_eliminate = true;
// fprintf(stderr, "delete %s %s\n", op->type.c_str(), op->name.c_str());
for (Operand* operand : op->inputs)
{
operand->remove_consumer(op);
}
op->inputs.clear();
for (Operand* operand : op->outputs)
{
operand->producer = 0;
}
op->outputs.clear();
graph.ops.erase(graph.ops.begin() + i);
delete op;
break;
}
}
if (!need_eliminate)
break;
}
// dead operand elimination
for (;;)
{
bool need_eliminate = false;
for (int i = (int)graph.operands.size() - 1; i >= 0; i--)
{
Operand* operand = graph.operands[i];
int consumers = (int)operand->consumers.size();
if (operand->producer == 0 && consumers == 0)
{
need_eliminate = true;
// fprintf(stderr, "delete operand %s\n", operand->name.c_str());
graph.operands.erase(graph.operands.begin() + i);
delete operand;
break;
}
}
if (!need_eliminate)
break;
}
}
} // namespace pnnx
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