19224500338

Committed 10 Nov 2025 07:48AM UTC coverage: 61.286% (+0.1%) from 61.165%

Build # 19224500338

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Commit Message

Merge pull request #332 from daisytuner/constant-elimination

handle previous definitions before constants in elimination pass

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9 existing lines in 4 files now uncovered.

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70.07

/src/passes/dataflow/constant_elimination.cpp

#include "sdfg/passes/dataflow/constant_elimination.h"

#include "sdfg/analysis/data_dependency_analysis.h"
#include "sdfg/analysis/dominance_analysis.h"
#include "sdfg/analysis/users.h"

namespace sdfg {
namespace passes {

ConstantElimination::ConstantElimination() : Pass() {};

std::string ConstantElimination::name() { return "ConstantElimination"; };

std::unordered_set<analysis::User*>
inputs(const std::string& container, data_flow::AccessNode* access_node, analysis::Users& users) {
    std::unordered_set<analysis::User*> inputs;

    auto& graph = access_node->get_parent();
    data_flow::Tasklet* tasklet = nullptr;
    for (auto& iedge : graph.in_edges(*access_node)) {
        tasklet = dynamic_cast<data_flow::Tasklet*>(&iedge.src());
    }
    if (tasklet == nullptr) {
        return {};
    }
    for (auto& iedge : graph.in_edges(*tasklet)) {
        auto& src_node = static_cast<data_flow::AccessNode&>(iedge.src());
        if (dynamic_cast<data_flow::ConstantNode*>(&src_node) != nullptr) {
            continue;
        }

        inputs.insert(users.get_user(src_node.data(), &src_node, analysis::Use::READ));
    }
    return inputs;
}

std::unordered_set<analysis::User*>
inputs(const std::string& container, structured_control_flow::Transition* transition, analysis::Users& users) {
    std::unordered_set<analysis::User*> inputs;
    auto& assign = transition->assignments().at(symbolic::symbol(container));
    for (auto& sym : symbolic::atoms(assign)) {
        if (symbolic::eq(sym, symbolic::__nullptr__())) {
            continue;
        }
        inputs.insert(users.get_user(sym->get_name(), transition, analysis::Use::READ));
    }
    return inputs;
}

std::unordered_set<analysis::User*> inputs(analysis::User& user, analysis::Users& users) {
    if (auto access_node = dynamic_cast<data_flow::AccessNode*>(user.element())) {
        return inputs(user.container(), access_node, users);
    } else if (auto transition = dynamic_cast<structured_control_flow::Transition*>(user.element())) {
        return inputs(user.container(), transition, users);
    } else {
        return {};
    }
}

bool ConstantElimination::run_pass(builder::StructuredSDFGBuilder& builder, analysis::AnalysisManager& analysis_manager) {
    bool applied = false;

    auto& sdfg = builder.subject();
    auto& users = analysis_manager.get<analysis::Users>();
    auto& dominance_analysis = analysis_manager.get<analysis::DominanceAnalysis>();
    auto& data_dependency_analysis = analysis_manager.get<analysis::DataDependencyAnalysis>();

    std::unordered_set<std::string> dead;
    for (auto& name : sdfg.containers()) {
        // Criterion: No aliases
        if (!users.views(name).empty() || !users.moves(name).empty()) {
            continue;
        }

        // Criterion: Two definitions
        auto definitions = data_dependency_analysis.definitions(name);
        if (definitions.size() < 2 || definitions.size() > 3) {
            continue;
        }
        // Filter our undefined user
        std::unordered_set<analysis::User*> defines;
        for (auto& def : definitions) {
            if (data_dependency_analysis.is_undefined_user(*def.first)) {
                continue;
            }
            defines.insert(def.first);
        }
        if (defines.size() != 2) {
            continue;
        }
        auto define1 = *defines.begin();
        auto define2 = *(++defines.begin());

        // Criterion: Identical define
        auto subsets1 = define1->subsets();
        auto subsets2 = define2->subsets();
        if (subsets1.size() != 1 || subsets2.size() != 1) {
            continue;
        }
        if (subsets1.begin()->size() != subsets2.begin()->size()) {
            continue;
        }
        bool constant_write = true;
        for (size_t i = 0; i < subsets1.begin()->size(); i++) {
            auto dim1 = subsets1.begin()->at(i);
            auto dim2 = subsets2.begin()->at(i);
            if (!symbolic::eq(dim1, dim2)) {
                constant_write = false;
                break;
            }
            if (!SymEngine::is_a<SymEngine::Integer>(*dim1)) {
                constant_write = false;
                break;
            }
        }
        if (!constant_write) {
            continue;
        }

        // Criterion: One dominates the other
        if (!dominance_analysis.dominates(*define1, *define2)) {
            std::swap(define1, define2);
        }
        if (!dominance_analysis.dominates(*define1, *define2)) {
            continue;
        }

        // Criterion: Inputs of definition are constant
        auto inputs1 = inputs(*define1, users);
        if (inputs1.empty()) {
            continue;
        }
        auto inputs2 = inputs(*define2, users);
        if (inputs2.empty()) {
            continue;
        }
        if (inputs1.size() != inputs2.size()) {
            continue;
        }
        bool constant_inputs = true;
        for (auto& input : inputs1) {
            // Recursion
            if (input->container() == name) {
                constant_inputs = false;
                break;
            }

            // input1 is constant
            if (users.views(input->container()).size() > 0) {
                constant_inputs = false;
                break;
            }
            for (auto& write_user : users.writes(input->container())) {
                if (!dominance_analysis.dominates(*write_user, *define1)) {
                    constant_inputs = false;
                    break;
                }
            }
            for (auto& move_user : users.moves(input->container())) {
                if (!dominance_analysis.dominates(*move_user, *define1)) {
                    constant_inputs = false;
                    break;
                }
            }

            // Find identical input in inputs2
            analysis::User* input2 = nullptr;
            for (auto& inp : inputs2) {
                if (input->container() == inp->container()) {
                    input2 = inp;
                    break;
                }
            }
            if (input2 == nullptr) {
                constant_inputs = false;
                break;
            }

            // same subsets
            if (input->subsets().size() != 1 || input2->subsets().size() != 1) {
                constant_inputs = false;
                break;
            }

            auto subset1 = *input->subsets().begin();
            auto subset2 = *input2->subsets().begin();
            if (subset1.size() != subset2.size()) {
                constant_inputs = false;
                break;
            }
            for (size_t i = 0; i < subset1.size(); i++) {
                auto dim1 = subset1[i];
                auto dim2 = subset2[i];
                if (!symbolic::eq(dim1, dim2)) {
                    constant_inputs = false;
                    break;
                }
                if (!SymEngine::is_a<SymEngine::Integer>(*dim1)) {
                    constant_inputs = false;
                    break;
                }
            }
        }
        if (!constant_inputs) {
            continue;
        }

        // Eliminate the dominated definition
        auto write = define2->element();
        if (auto transition = dynamic_cast<structured_control_flow::Transition*>(write)) {
            transition->assignments().erase(symbolic::symbol(name));
            applied = true;
        } else if (auto access_node = dynamic_cast<data_flow::AccessNode*>(write)) {
            auto& graph = access_node->get_parent();
            if (graph.out_degree(*access_node) > 0) {
                continue;
            }
            auto& block = dynamic_cast<structured_control_flow::Block&>(*graph.get_parent());
            builder.clear_node(block, *access_node);
            applied = true;
        }
    }

    return applied;
};

} // namespace passes
} // namespace sdfg

1	#include "sdfg/passes/dataflow/constant_elimination.h"
2
3	#include "sdfg/analysis/data_dependency_analysis.h"
4	#include "sdfg/analysis/dominance_analysis.h"
5	#include "sdfg/analysis/users.h"
6
7	namespace sdfg {
8	namespace passes {
9
10	ConstantElimination::ConstantElimination() : Pass() {};	7✔
11
12	std::string ConstantElimination::name() { return "ConstantElimination"; };	×
13
14	std::unordered_set<analysis::User*>
15	inputs(const std::string& container, data_flow::AccessNode* access_node, analysis::Users& users) {	4✔
16	std::unordered_set<analysis::User*> inputs;	4✔
17
18	auto& graph = access_node->get_parent();	4✔
19	data_flow::Tasklet* tasklet = nullptr;	4✔
20	for (auto& iedge : graph.in_edges(*access_node)) {	8✔
21	tasklet = dynamic_cast<data_flow::Tasklet*>(&iedge.src());	4✔
22	}
23	if (tasklet == nullptr) {	4✔
24	return {};	×
25	}
26	for (auto& iedge : graph.in_edges(*tasklet)) {	8✔
27	auto& src_node = static_cast<data_flow::AccessNode&>(iedge.src());	4✔
28	if (dynamic_cast<data_flow::ConstantNode*>(&src_node) != nullptr) {	4✔
29	continue;	×
30	}
31
32	inputs.insert(users.get_user(src_node.data(), &src_node, analysis::Use::READ));	4✔
33	}
34	return inputs;	4✔
35	}	4✔
36
37	std::unordered_set<analysis::User*>
38	inputs(const std::string& container, structured_control_flow::Transition* transition, analysis::Users& users) {	8✔
39	std::unordered_set<analysis::User*> inputs;	8✔
40	auto& assign = transition->assignments().at(symbolic::symbol(container));	8✔
41	for (auto& sym : symbolic::atoms(assign)) {	16✔
42	if (symbolic::eq(sym, symbolic::__nullptr__())) {	8✔
UNCOV 43	continue;	×
44	}
45	inputs.insert(users.get_user(sym->get_name(), transition, analysis::Use::READ));	8✔
46	}
47	return inputs;	8✔
48	}	8✔
49
50	std::unordered_set<analysis::User*> inputs(analysis::User& user, analysis::Users& users) {	12✔
51	if (auto access_node = dynamic_cast<data_flow::AccessNode*>(user.element())) {	12✔
52	return inputs(user.container(), access_node, users);	4✔
53	} else if (auto transition = dynamic_cast<structured_control_flow::Transition*>(user.element())) {	8✔
54	return inputs(user.container(), transition, users);	8✔
55	} else {
56	return {};	×
57	}
58	}	12✔
59
60	bool ConstantElimination::run_pass(builder::StructuredSDFGBuilder& builder, analysis::AnalysisManager& analysis_manager) {	6✔
61	bool applied = false;	6✔
62
63	auto& sdfg = builder.subject();	6✔
64	auto& users = analysis_manager.get<analysis::Users>();	6✔
65	auto& dominance_analysis = analysis_manager.get<analysis::DominanceAnalysis>();	6✔
66	auto& data_dependency_analysis = analysis_manager.get<analysis::DataDependencyAnalysis>();	6✔
67
68	std::unordered_set<std::string> dead;	6✔
69	for (auto& name : sdfg.containers()) {	18✔
70	// Criterion: No aliases
71	if (!users.views(name).empty() \|\| !users.moves(name).empty()) {	12✔
72	continue;	×
73	}
74
75	// Criterion: Two definitions
76	auto definitions = data_dependency_analysis.definitions(name);	12✔
77	if (definitions.size() < 2 \|\| definitions.size() > 3) {	12✔
78	continue;	6✔
79	}
80	// Filter our undefined user
81	std::unordered_set<analysis::User*> defines;	6✔
82	for (auto& def : definitions) {	19✔
83	if (data_dependency_analysis.is_undefined_user(*def.first)) {	13✔
84	continue;	1✔
85	}
86	defines.insert(def.first);	12✔
87	}
88	if (defines.size() != 2) {	6✔
UNCOV 89	continue;	×
90	}
91	auto define1 = *defines.begin();	6✔
92	auto define2 = *(++defines.begin());	6✔
93
94	// Criterion: Identical define
95	auto subsets1 = define1->subsets();	6✔
96	auto subsets2 = define2->subsets();	6✔
97	if (subsets1.size() != 1 \|\| subsets2.size() != 1) {	6✔
98	continue;	×
99	}
100	if (subsets1.begin()->size() != subsets2.begin()->size()) {	6✔
101	continue;	×
102	}
103	bool constant_write = true;	6✔
104	for (size_t i = 0; i < subsets1.begin()->size(); i++) {	6✔
105	auto dim1 = subsets1.begin()->at(i);	×
106	auto dim2 = subsets2.begin()->at(i);	×
107	if (!symbolic::eq(dim1, dim2)) {	×
108	constant_write = false;	×
109	break;	×
110	}
111	if (!SymEngine::is_a<SymEngine::Integer>(*dim1)) {	×
112	constant_write = false;	×
113	break;	×
114	}
115	}	×
116	if (!constant_write) {	6✔
117	continue;	×
118	}
119
120	// Criterion: One dominates the other
121	if (!dominance_analysis.dominates(define1, define2)) {	6✔
122	std::swap(define1, define2);	4✔
123	}	4✔
124	if (!dominance_analysis.dominates(define1, define2)) {	6✔
125	continue;	×
126	}
127
128	// Criterion: Inputs of definition are constant
129	auto inputs1 = inputs(*define1, users);	6✔
130	if (inputs1.empty()) {	6✔
131	continue;	×
132	}
133	auto inputs2 = inputs(*define2, users);	6✔
134	if (inputs2.empty()) {	6✔
135	continue;	×
136	}
137	if (inputs1.size() != inputs2.size()) {	6✔
138	continue;	×
139	}
140	bool constant_inputs = true;	6✔
141	for (auto& input : inputs1) {	12✔
142	// Recursion
143	if (input->container() == name) {	6✔
144	constant_inputs = false;	×
145	break;	×
146	}
147
148	// input1 is constant
149	if (users.views(input->container()).size() > 0) {	6✔
UNCOV 150	constant_inputs = false;	×
151	break;	×
152	}
153	for (auto& write_user : users.writes(input->container())) {	10✔
154	if (!dominance_analysis.dominates(write_user, define1)) {	4✔
NEW 155	constant_inputs = false;	×
NEW 156	break;	×
157	}
158	}
159	for (auto& move_user : users.moves(input->container())) {	6✔
NEW 160	if (!dominance_analysis.dominates(move_user, define1)) {	×
NEW 161	constant_inputs = false;	×
NEW 162	break;	×
163	}
164	}
165
166	// Find identical input in inputs2
167	analysis::User* input2 = nullptr;	6✔
168	for (auto& inp : inputs2) {	6✔
169	if (input->container() == inp->container()) {	6✔
170	input2 = inp;	6✔
171	break;	6✔
172	}
173	}
174	if (input2 == nullptr) {	6✔
175	constant_inputs = false;	×
176	break;	×
177	}
178
179	// same subsets
180	if (input->subsets().size() != 1 \|\| input2->subsets().size() != 1) {	6✔
181	constant_inputs = false;	×
182	break;	×
183	}
184
185	auto subset1 = *input->subsets().begin();	6✔
186	auto subset2 = *input2->subsets().begin();	6✔
187	if (subset1.size() != subset2.size()) {	6✔
188	constant_inputs = false;	×
189	break;	×
190	}
191	for (size_t i = 0; i < subset1.size(); i++) {	8✔
192	auto dim1 = subset1[i];	2✔
193	auto dim2 = subset2[i];	2✔
194	if (!symbolic::eq(dim1, dim2)) {	2✔
195	constant_inputs = false;	×
196	break;	×
197	}
198	if (!SymEngine::is_a<SymEngine::Integer>(*dim1)) {	2✔
199	constant_inputs = false;	×
200	break;	×
201	}
202	}	2✔
203	}	6✔
204	if (!constant_inputs) {	6✔
205	continue;	×
206	}
207
208	// Eliminate the dominated definition
209	auto write = define2->element();	6✔
210	if (auto transition = dynamic_cast<structured_control_flow::Transition*>(write)) {	6✔
211	transition->assignments().erase(symbolic::symbol(name));	4✔
212	applied = true;	4✔
213	} else if (auto access_node = dynamic_cast<data_flow::AccessNode*>(write)) {	6✔
214	auto& graph = access_node->get_parent();	2✔
215	if (graph.out_degree(*access_node) > 0) {	2✔
216	continue;	×
217	}
218	auto& block = dynamic_cast<structured_control_flow::Block&>(*graph.get_parent());	2✔
219	builder.clear_node(block, *access_node);	2✔
220	applied = true;	2✔
221	}	2✔
222	}	12✔
223
224	return applied;	6✔
225	};	6✔
226
227	} // namespace passes
228	} // namespace sdfg

daisytuner / sdfglib / 19224500338

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