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/*
* Copyright (C) 2016 The Android Open Source Project
*
* 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 "loop_optimization.h"
#include "optimizing_unit_test.h"
namespace art {
/**
* Fixture class for the loop optimization tests. These unit tests focus
* constructing the loop hierarchy. Actual optimizations are tested
* through the checker tests.
*/
class LoopOptimizationTest : public CommonCompilerTest {
public:
LoopOptimizationTest()
: pool_(),
allocator_(&pool_),
graph_(CreateGraph(&allocator_)),
iva_(new (&allocator_) HInductionVarAnalysis(graph_)),
loop_opt_(new (&allocator_) HLoopOptimization(graph_, nullptr, iva_)) {
BuildGraph();
}
~LoopOptimizationTest() { }
/** Constructs bare minimum graph. */
void BuildGraph() {
graph_->SetNumberOfVRegs(1);
entry_block_ = new (&allocator_) HBasicBlock(graph_);
return_block_ = new (&allocator_) HBasicBlock(graph_);
exit_block_ = new (&allocator_) HBasicBlock(graph_);
graph_->AddBlock(entry_block_);
graph_->AddBlock(return_block_);
graph_->AddBlock(exit_block_);
graph_->SetEntryBlock(entry_block_);
graph_->SetExitBlock(exit_block_);
parameter_ = new (&allocator_) HParameterValue(graph_->GetDexFile(),
dex::TypeIndex(0),
0,
Primitive::kPrimInt);
entry_block_->AddInstruction(parameter_);
return_block_->AddInstruction(new (&allocator_) HReturnVoid());
exit_block_->AddInstruction(new (&allocator_) HExit());
entry_block_->AddSuccessor(return_block_);
return_block_->AddSuccessor(exit_block_);
}
/** Adds a loop nest at given position before successor. */
HBasicBlock* AddLoop(HBasicBlock* position, HBasicBlock* successor) {
HBasicBlock* header = new (&allocator_) HBasicBlock(graph_);
HBasicBlock* body = new (&allocator_) HBasicBlock(graph_);
graph_->AddBlock(header);
graph_->AddBlock(body);
// Control flow.
position->ReplaceSuccessor(successor, header);
header->AddSuccessor(body);
header->AddSuccessor(successor);
header->AddInstruction(new (&allocator_) HIf(parameter_));
body->AddSuccessor(header);
body->AddInstruction(new (&allocator_) HGoto());
return header;
}
/** Performs analysis. */
void PerformAnalysis() {
graph_->BuildDominatorTree();
iva_->Run();
// Do not release the loop hierarchy.
loop_opt_->loop_allocator_ = &allocator_;
loop_opt_->LocalRun();
}
/** Constructs string representation of computed loop hierarchy. */
std::string LoopStructure() {
return LoopStructureRecurse(loop_opt_->top_loop_);
}
// Helper method
std::string LoopStructureRecurse(HLoopOptimization::LoopNode* node) {
std::string s;
for ( ; node != nullptr; node = node->next) {
s.append("[");
s.append(LoopStructureRecurse(node->inner));
s.append("]");
}
return s;
}
// General building fields.
ArenaPool pool_;
ArenaAllocator allocator_;
HGraph* graph_;
HInductionVarAnalysis* iva_;
HLoopOptimization* loop_opt_;
HBasicBlock* entry_block_;
HBasicBlock* return_block_;
HBasicBlock* exit_block_;
HInstruction* parameter_;
};
//
// The actual tests.
//
TEST_F(LoopOptimizationTest, NoLoops) {
PerformAnalysis();
EXPECT_EQ("", LoopStructure());
}
TEST_F(LoopOptimizationTest, SingleLoop) {
AddLoop(entry_block_, return_block_);
PerformAnalysis();
EXPECT_EQ("[]", LoopStructure());
}
TEST_F(LoopOptimizationTest, LoopNest10) {
HBasicBlock* b = entry_block_;
HBasicBlock* s = return_block_;
for (int i = 0; i < 10; i++) {
s = AddLoop(b, s);
b = s->GetSuccessors()[0];
}
PerformAnalysis();
EXPECT_EQ("[[[[[[[[[[]]]]]]]]]]", LoopStructure());
}
TEST_F(LoopOptimizationTest, LoopSequence10) {
HBasicBlock* b = entry_block_;
HBasicBlock* s = return_block_;
for (int i = 0; i < 10; i++) {
b = AddLoop(b, s);
s = b->GetSuccessors()[1];
}
PerformAnalysis();
EXPECT_EQ("[][][][][][][][][][]", LoopStructure());
}
TEST_F(LoopOptimizationTest, LoopSequenceOfNests) {
HBasicBlock* b = entry_block_;
HBasicBlock* s = return_block_;
for (int i = 0; i < 10; i++) {
b = AddLoop(b, s);
s = b->GetSuccessors()[1];
HBasicBlock* bi = b->GetSuccessors()[0];
HBasicBlock* si = b;
for (int j = 0; j < i; j++) {
si = AddLoop(bi, si);
bi = si->GetSuccessors()[0];
}
}
PerformAnalysis();
EXPECT_EQ("[]"
"[[]]"
"[[[]]]"
"[[[[]]]]"
"[[[[[]]]]]"
"[[[[[[]]]]]]"
"[[[[[[[]]]]]]]"
"[[[[[[[[]]]]]]]]"
"[[[[[[[[[]]]]]]]]]"
"[[[[[[[[[[]]]]]]]]]]",
LoopStructure());
}
TEST_F(LoopOptimizationTest, LoopNestWithSequence) {
HBasicBlock* b = entry_block_;
HBasicBlock* s = return_block_;
for (int i = 0; i < 10; i++) {
s = AddLoop(b, s);
b = s->GetSuccessors()[0];
}
b = s;
s = b->GetSuccessors()[1];
for (int i = 0; i < 9; i++) {
b = AddLoop(b, s);
s = b->GetSuccessors()[1];
}
PerformAnalysis();
EXPECT_EQ("[[[[[[[[[[][][][][][][][][][]]]]]]]]]]", LoopStructure());
}
// Check that SimplifyLoop() doesn't invalidate data flow when ordering loop headers'
// predecessors.
TEST_F(LoopOptimizationTest, SimplifyLoop) {
// Can't use AddLoop as we want special order for blocks predecessors.
HBasicBlock* header = new (&allocator_) HBasicBlock(graph_);
HBasicBlock* body = new (&allocator_) HBasicBlock(graph_);
graph_->AddBlock(header);
graph_->AddBlock(body);
// Control flow: make a loop back edge first in the list of predecessors.
entry_block_->RemoveSuccessor(return_block_);
body->AddSuccessor(header);
entry_block_->AddSuccessor(header);
header->AddSuccessor(body);
header->AddSuccessor(return_block_);
DCHECK(header->GetSuccessors()[1] == return_block_);
// Data flow.
header->AddInstruction(new (&allocator_) HIf(parameter_));
body->AddInstruction(new (&allocator_) HGoto());
HPhi* phi = new (&allocator_) HPhi(&allocator_, 0, 0, Primitive::kPrimInt);
HInstruction* add = new (&allocator_) HAdd(Primitive::kPrimInt, phi, parameter_);
header->AddPhi(phi);
body->AddInstruction(add);
phi->AddInput(add);
phi->AddInput(parameter_);
graph_->ClearLoopInformation();
graph_->ClearDominanceInformation();
graph_->BuildDominatorTree();
// Check that after optimizations in BuildDominatorTree()/SimplifyCFG() phi inputs
// are still mapped correctly to the block predecessors.
for (size_t i = 0, e = phi->InputCount(); i < e; i++) {
HInstruction* input = phi->InputAt(i);
ASSERT_TRUE(input->GetBlock()->Dominates(header->GetPredecessors()[i]));
}
}
} // namespace art
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