mindspore2022/mindspore/ccsrc/frontend/optimizer/cse.cc

232 lines
7.7 KiB
C++

/**
* This is the C++ adaptation and derivative work of Myia (https://github.com/mila-iqia/myia/).
*
* Copyright 2019 Huawei Technologies Co., Ltd
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* 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 "frontend/optimizer/cse.h"
#include <vector>
#include <set>
#include <unordered_map>
#include "./common.h"
namespace mindspore {
/* namespace to support opt */
namespace opt {
using mindspore::abstract::AbstractBase;
using mindspore::abstract::AbstractFunction;
using mindspore::abstract::AbstractFunctionPtr;
BasePtr AbsOf(const AnfNodePtr &node) {
MS_EXCEPTION_IF_NULL(node);
auto node_abs = node->abstract();
// in testcase: TestOptOpt.CSE, node->abstract() is null;
if (node_abs == nullptr) {
return kAnyValue;
}
return node_abs;
}
bool CSE::BuildOrderGroupAndDoReplace(const FuncGraphManagerPtr manager) const {
bool changed = false;
for (FuncGraphPtr fg : manager->func_graphs()) {
MS_EXCEPTION_IF_NULL(fg);
std::vector<std::size_t> order_group;
std::unordered_map<std::size_t, std::vector<AnfNodePtr>> groups;
std::unordered_map<AnfNodePtr, std::size_t> hashes;
std::vector<AnfNodePtr> toposet = TopoSort(fg->get_return());
for (auto node : toposet) {
MS_EXCEPTION_IF_NULL(node);
if (hashes.find(node) != hashes.end()) {
continue;
}
std::size_t h = 0;
if (node->isa<ValueNode>()) {
ValueNodePtr value_node = node->cast<ValueNodePtr>();
auto value = value_node->value();
MS_EXCEPTION_IF_NULL(value);
h = hash_combine(value->hash(), (AbsOf(value_node)->hash()));
} else if (node->isa<CNode>()) {
auto cnode = node->cast<CNodePtr>();
auto &inputs = cnode->inputs();
size_t init = 0;
h = std::accumulate(inputs.begin(), inputs.end(), init, [&hashes](std::size_t hash, const AnfNodePtr &node_in) {
return hash_combine(hash, hashes[node_in]);
});
} else if (node->isa<Parameter>()) {
h = node->hash();
} else {
MS_LOG(ERROR) << "Unknow node type";
}
hashes[node] = h;
if (groups.find(h) == groups.end()) {
std::vector<AnfNodePtr> innervec({node});
groups[h] = innervec;
order_group.emplace_back(h);
} else {
groups[h].push_back(node);
}
}
changed = DoReplace(manager, order_group, &groups) || changed;
}
return changed;
}
// The op like print, summary, or the op do not has true output, and always as a depend node input.
static bool HasSideEffect(const AnfNodePtr &node) {
auto prim = GetCNodePrimitive(node);
if (prim == nullptr) {
return false;
}
auto side_effect_v = prim->GetAttr(GRAPH_FLAG_SIDE_EFFECT);
if (side_effect_v != nullptr && side_effect_v->isa<BoolImm>()) {
return GetValue<bool>(side_effect_v);
}
return false;
}
// If true do not merge the node.
bool CSE::CheckRandomEffect(const AnfNodePtr &main, const AnfNodePtr &node) const {
bool has_random_effect = false;
auto prim_main = GetCNodePrimitive(main);
auto prim_node = GetCNodePrimitive(node);
// if has random effect, when generate by different op (not same object), do not merge.
if (prim_main != nullptr) {
if (prim_main == prim_node) {
return false;
}
auto effect_val = prim_main->GetAttr(GRAPH_FLAG_RANDOM_EFFECT);
if (effect_val != nullptr && effect_val->isa<BoolImm>()) {
has_random_effect = GetValue<bool>(effect_val);
}
}
return has_random_effect;
}
bool CSE::CheckReplace(const AnfNodePtr &main, const AnfNodePtr &node, bool check_side_effect) const {
MS_EXCEPTION_IF_NULL(main);
MS_EXCEPTION_IF_NULL(node);
if (main->isa<ValueNode>() && node->isa<ValueNode>()) {
auto main_value = GetValueNode(main);
auto node_value = GetValueNode(node);
return (AbsOf(main) == AbsOf(node)) && (*main_value == *node_value);
} else if (main->isa<CNode>() && node->isa<CNode>()) {
auto c_main = main->cast<CNodePtr>();
auto c_node = node->cast<CNodePtr>();
// When appsame is true, check if has side effect, do not merge.
if (check_side_effect && HasSideEffect(main)) {
return false;
}
const auto &inp1 = c_main->inputs();
const auto &inp2 = c_node->inputs();
if (inp1.size() != inp2.size()) {
return false;
}
for (size_t j = 0; j < inp1.size(); j++) {
auto inp1_j = inp1[j];
auto inp2_j = inp2[j];
MS_EXCEPTION_IF_NULL(inp1_j);
MS_EXCEPTION_IF_NULL(inp2_j);
if (!(*inp1_j == *inp2_j)) {
// Handle the case of two different Tensor, but with the same value
if (IsValueNode<tensor::Tensor>(inp1_j) && IsValueNode<tensor::Tensor>(inp2_j)) {
auto tensor1 = GetValueNode<tensor::TensorPtr>(inp1_j);
auto tensor2 = GetValueNode<tensor::TensorPtr>(inp2_j);
if (tensor1->ValueEqual(*tensor2)) {
continue;
}
} else if (HasSideEffect(inp1_j) && HasSideEffect(inp2_j)) {
// When the same side effect node as another two nodes' inputs, we still merge the node.
// Because the node only can be the inputs of `depend`, when the `depend` is duplicated merge the depend the
// node.
if (CheckReplace(inp1_j, inp2_j, false)) {
continue;
}
}
return false;
}
}
// When appsame is true, check if has random effect do not merge
if (CheckRandomEffect(c_main, c_node)) {
return false;
}
return true;
}
// a parameter node.
return false;
}
bool CSE::DoReplace(const FuncGraphManagerPtr manager, const std::vector<std::size_t> &order_group,
std::unordered_map<std::size_t, std::vector<AnfNodePtr>> *groups) const {
bool changes = false;
std::set<size_t> clear_set;
for (auto &h : order_group) {
std::vector<AnfNodePtr> &group = (*groups)[h];
// If there are more than 2 node in that group, they may be same common expression can be eliminated.
if (group.size() > 1) {
for (size_t k = 0; k < group.size() - 1; k++) {
AnfNodePtr main = group[k];
MS_EXCEPTION_IF_NULL(main);
// When all node in group has been replaced
// or a valuenode node, skip compare in group
if ((k + 1 + clear_set.size() == group.size()) || (k > 0 && main->isa<ValueNode>())) {
break;
}
// skip node has been replaced
if (clear_set.find(k) != clear_set.end()) {
continue;
}
// Compare with rest elements in this group.
for (size_t i = k + 1; i < group.size(); i++) {
auto node = group[i];
MS_EXCEPTION_IF_NULL(node);
if (clear_set.find(i) != clear_set.end()) {
continue;
}
if (main->func_graph() != node->func_graph()) {
continue;
}
if (CheckReplace(node, main)) {
changes = true;
(void)manager->Replace(node, main);
(void)clear_set.insert(i);
}
}
}
clear_set.clear();
}
}
return changes;
}
bool CSE::Cse(const FuncGraphPtr root, const FuncGraphManagerPtr manager) const {
MS_EXCEPTION_IF_NULL(manager);
manager->AddFuncGraph(root);
return BuildOrderGroupAndDoReplace(manager);
}
} // namespace opt
} // namespace mindspore