reduce: add remove_selection_reduction_opportunity (#2485)

Fix #2484
This commit is contained in:
Paul Thomson 2019-04-02 16:50:15 +01:00 committed by GitHub
parent c9874e5090
commit e2ddb9371e
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8 changed files with 840 additions and 0 deletions

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@ -30,6 +30,8 @@ set(SPIRV_TOOLS_REDUCE_SOURCES
remove_function_reduction_opportunity.h
remove_function_reduction_opportunity_finder.h
remove_opname_instruction_reduction_opportunity_finder.h
remove_selection_reduction_opportunity.h
remove_selection_reduction_opportunity_finder.h
remove_unreferenced_instruction_reduction_opportunity_finder.h
structured_loop_to_selection_reduction_opportunity.h
structured_loop_to_selection_reduction_opportunity_finder.h
@ -50,6 +52,8 @@ set(SPIRV_TOOLS_REDUCE_SOURCES
remove_function_reduction_opportunity.cpp
remove_function_reduction_opportunity_finder.cpp
remove_instruction_reduction_opportunity.cpp
remove_selection_reduction_opportunity.cpp
remove_selection_reduction_opportunity_finder.cpp
remove_unreferenced_instruction_reduction_opportunity_finder.cpp
remove_opname_instruction_reduction_opportunity_finder.cpp
structured_loop_to_selection_reduction_opportunity.cpp

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@ -21,6 +21,7 @@
#include "source/reduce/operand_to_undef_reduction_opportunity_finder.h"
#include "source/reduce/remove_function_reduction_opportunity_finder.h"
#include "source/reduce/remove_opname_instruction_reduction_opportunity_finder.h"
#include "source/reduce/remove_selection_reduction_opportunity_finder.h"
#include "source/reduce/remove_unreferenced_instruction_reduction_opportunity_finder.h"
#include "source/reduce/structured_loop_to_selection_reduction_opportunity_finder.h"
#include "source/spirv_reducer_options.h"
@ -185,6 +186,8 @@ void Reducer::AddDefaultReductionPasses() {
spvtools::MakeUnique<MergeBlocksReductionOpportunityFinder>());
AddReductionPass(
spvtools::MakeUnique<RemoveFunctionReductionOpportunityFinder>());
AddReductionPass(
spvtools::MakeUnique<RemoveSelectionReductionOpportunityFinder>());
}
void Reducer::AddReductionPass(

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@ -0,0 +1,31 @@
// Copyright (c) 2019 Google LLC
//
// 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 "source/reduce/remove_selection_reduction_opportunity.h"
#include "source/opt/basic_block.h"
#include "source/opt/ir_context.h"
namespace spvtools {
namespace reduce {
bool RemoveSelectionReductionOpportunity::PreconditionHolds() { return true; }
void RemoveSelectionReductionOpportunity::Apply() {
auto merge_instruction = header_block_->GetMergeInst();
merge_instruction->context()->KillInst(merge_instruction);
}
} // namespace reduce
} // namespace spvtools

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@ -0,0 +1,47 @@
// Copyright (c) 2019 Google LLC
//
// 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.
#ifndef SOURCE_REDUCE_REMOVE_SELECTION_REDUCTION_OPPORTUNITY_H_
#define SOURCE_REDUCE_REMOVE_SELECTION_REDUCTION_OPPORTUNITY_H_
#include "source/opt/basic_block.h"
#include "source/reduce/reduction_opportunity.h"
namespace spvtools {
namespace reduce {
// An opportunity for removing a selection construct by simply removing the
// OpSelectionMerge instruction; thus, the selection must have already been
// simplified to a point where the instruction can be trivially removed.
class RemoveSelectionReductionOpportunity : public ReductionOpportunity {
public:
// Constructs a reduction opportunity from the selection header |block| in
// |function|.
RemoveSelectionReductionOpportunity(opt::BasicBlock* header_block)
: header_block_(header_block) {}
bool PreconditionHolds() override;
protected:
void Apply() override;
private:
// The header block of the selection.
opt::BasicBlock* header_block_;
};
} // namespace reduce
} // namespace spvtools
#endif // SOURCE_REDUCE_REMOVE_SELECTION_REDUCTION_OPPORTUNITY_H_

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@ -0,0 +1,148 @@
// Copyright (c) 2019 Google Inc.
//
// 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 "source/reduce/remove_selection_reduction_opportunity_finder.h"
#include "source/reduce/remove_selection_reduction_opportunity.h"
namespace spvtools {
namespace reduce {
using namespace opt;
namespace {
const uint32_t kMergeNodeIndex = 0;
const uint32_t kContinueNodeIndex = 1;
} // namespace
std::string RemoveSelectionReductionOpportunityFinder::GetName() const {
return "RemoveSelectionReductionOpportunityFinder";
}
std::vector<std::unique_ptr<ReductionOpportunity>>
RemoveSelectionReductionOpportunityFinder::GetAvailableOpportunities(
opt::IRContext* context) const {
// Get all loop merge and continue blocks so we can check for these later.
std::unordered_set<uint32_t> merge_and_continue_blocks_from_loops;
for (auto& function : *context->module()) {
for (auto& block : function) {
if (auto merge_instruction = block.GetMergeInst()) {
if (merge_instruction->opcode() == SpvOpLoopMerge) {
uint32_t merge_block_id =
merge_instruction->GetSingleWordOperand(kMergeNodeIndex);
uint32_t continue_block_id =
merge_instruction->GetSingleWordOperand(kContinueNodeIndex);
merge_and_continue_blocks_from_loops.insert(merge_block_id);
merge_and_continue_blocks_from_loops.insert(continue_block_id);
}
}
}
}
// Return all selection headers where the OpSelectionMergeInstruction can be
// removed.
std::vector<std::unique_ptr<ReductionOpportunity>> result;
for (auto& function : *context->module()) {
for (auto& block : function) {
if (auto merge_instruction = block.GetMergeInst()) {
if (merge_instruction->opcode() == SpvOpSelectionMerge) {
if (CanOpSelectionMergeBeRemoved(
context, block, merge_instruction,
merge_and_continue_blocks_from_loops)) {
result.push_back(
MakeUnique<RemoveSelectionReductionOpportunity>(&block));
}
}
}
}
}
return result;
}
bool RemoveSelectionReductionOpportunityFinder::CanOpSelectionMergeBeRemoved(
opt::IRContext* context, const opt::BasicBlock& header_block,
opt::Instruction* merge_instruction,
std::unordered_set<uint32_t> merge_and_continue_blocks_from_loops) {
assert(header_block.GetMergeInst() == merge_instruction &&
"CanOpSelectionMergeBeRemoved(...): header block and merge "
"instruction mismatch");
// The OpSelectionMerge instruction is needed if either of the following are
// true.
//
// 1. The header block has at least two (unique) successors that are not
// merge or continue blocks of a loop.
//
// 2. The predecessors of the merge block are "using" the merge block to avoid
// divergence. In other words, there exists a predecessor of the merge block
// that has a successor that is not the merge block of this construct and not
// a merge or continue block of a loop.
// 1.
{
uint32_t divergent_successor_count = 0;
std::unordered_set<uint32_t> seen_successors;
header_block.ForEachSuccessorLabel(
[&seen_successors, &merge_and_continue_blocks_from_loops,
&divergent_successor_count](uint32_t successor) {
// Not already seen.
if (seen_successors.find(successor) == seen_successors.end()) {
seen_successors.insert(successor);
// Not a loop continue or merge.
if (merge_and_continue_blocks_from_loops.find(successor) ==
merge_and_continue_blocks_from_loops.end()) {
++divergent_successor_count;
}
}
});
if (divergent_successor_count > 1) {
return false;
}
}
// 2.
{
uint32_t merge_block_id =
merge_instruction->GetSingleWordOperand(kMergeNodeIndex);
for (uint32_t predecessor_block_id :
context->cfg()->preds(merge_block_id)) {
const BasicBlock* predecessor_block =
context->cfg()->block(predecessor_block_id);
assert(predecessor_block);
bool found_divergent_successor = false;
predecessor_block->ForEachSuccessorLabel(
[&found_divergent_successor, merge_block_id,
&merge_and_continue_blocks_from_loops](uint32_t successor_id) {
// The successor is not the merge block, nor a loop merge or
// continue.
if (successor_id != merge_block_id &&
merge_and_continue_blocks_from_loops.find(successor_id) ==
merge_and_continue_blocks_from_loops.end()) {
found_divergent_successor = true;
}
});
if (found_divergent_successor) {
return false;
}
}
}
return true;
}
} // namespace reduce
} // namespace spvtools

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@ -0,0 +1,49 @@
// Copyright (c) 2019 Google LLC
//
// 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.
#ifndef SOURCE_REDUCE_REMOVE_SELECTION_REDUCTION_OPPORTUNITY_FINDER_H_
#define SOURCE_REDUCE_REMOVE_SELECTION_REDUCTION_OPPORTUNITY_FINDER_H_
#include "source/reduce/reduction_opportunity_finder.h"
namespace spvtools {
namespace reduce {
// A finder for opportunities for removing a selection construct by simply
// removing the OpSelectionMerge instruction; thus, the selections must have
// already been simplified to a point where they can be trivially removed.
class RemoveSelectionReductionOpportunityFinder
: public ReductionOpportunityFinder {
public:
RemoveSelectionReductionOpportunityFinder() = default;
~RemoveSelectionReductionOpportunityFinder() override = default;
std::string GetName() const final;
std::vector<std::unique_ptr<ReductionOpportunity>> GetAvailableOpportunities(
opt::IRContext* context) const final;
// Returns true if the OpSelectionMerge instruction |merge_instruction| in
// block |header_block| can be removed.
static bool CanOpSelectionMergeBeRemoved(
opt::IRContext* context, const opt::BasicBlock& header_block,
opt::Instruction* merge_instruction,
std::unordered_set<uint32_t> merge_and_continue_blocks_from_loops);
};
} // namespace reduce
} // namespace spvtools
#endif // SOURCE_REDUCE_REMOVE_SELECTION_REDUCTION_OPPORTUNITY_FINDER_H_

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@ -23,6 +23,7 @@ add_spvtools_unittest(TARGET reduce
remove_block_test.cpp
remove_function_test.cpp
remove_opname_instruction_test.cpp
remove_selection_test.cpp
remove_unreferenced_instruction_test.cpp
structured_loop_to_selection_test.cpp
validation_during_reduction_test.cpp

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@ -0,0 +1,557 @@
// Copyright (c) 2019 Google LLC
//
// 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 "source/opt/build_module.h"
#include "source/reduce/reduction_opportunity.h"
#include "source/reduce/reduction_pass.h"
#include "source/reduce/remove_selection_reduction_opportunity_finder.h"
#include "test/reduce/reduce_test_util.h"
namespace spvtools {
namespace reduce {
namespace {
TEST(RemoveSelectionTest, OpportunityBecauseSameTargetBlock) {
// A test with the following structure. The OpSelectionMerge instruction
// should be removed.
//
// header
// ||
// block
// |
// merge
std::string shader = R"(
OpCapability Shader
%1 = OpExtInstImport "GLSL.std.450"
OpMemoryModel Logical GLSL450
OpEntryPoint Fragment %2 "main"
OpExecutionMode %2 OriginUpperLeft
OpSource ESSL 310
OpName %2 "main"
%3 = OpTypeVoid
%4 = OpTypeFunction %3
%5 = OpTypeInt 32 1
%6 = OpTypePointer Function %5
%7 = OpTypeBool
%8 = OpConstantTrue %7
%2 = OpFunction %3 None %4
%9 = OpLabel
OpSelectionMerge %10 None
OpBranchConditional %8 %11 %11
%11 = OpLabel
OpBranch %10
%10 = OpLabel
OpReturn
OpFunctionEnd
)";
const auto env = SPV_ENV_UNIVERSAL_1_3;
const auto context = BuildModule(env, nullptr, shader, kReduceAssembleOption);
auto ops =
RemoveSelectionReductionOpportunityFinder().GetAvailableOpportunities(
context.get());
ASSERT_EQ(1, ops.size());
ASSERT_TRUE(ops[0]->PreconditionHolds());
ops[0]->TryToApply();
CheckValid(env, context.get());
std::string after = R"(
OpCapability Shader
%1 = OpExtInstImport "GLSL.std.450"
OpMemoryModel Logical GLSL450
OpEntryPoint Fragment %2 "main"
OpExecutionMode %2 OriginUpperLeft
OpSource ESSL 310
OpName %2 "main"
%3 = OpTypeVoid
%4 = OpTypeFunction %3
%5 = OpTypeInt 32 1
%6 = OpTypePointer Function %5
%7 = OpTypeBool
%8 = OpConstantTrue %7
%2 = OpFunction %3 None %4
%9 = OpLabel
OpBranchConditional %8 %11 %11
%11 = OpLabel
OpBranch %10
%10 = OpLabel
OpReturn
OpFunctionEnd
)";
CheckEqual(env, after, context.get());
ops = RemoveSelectionReductionOpportunityFinder().GetAvailableOpportunities(
context.get());
ASSERT_EQ(0, ops.size());
}
TEST(RemoveSelectionTest, OpportunityBecauseSameTargetBlockMerge) {
// A test with the following structure. The OpSelectionMerge instruction
// should be removed.
//
// header
// ||
// merge
std::string shader = R"(
OpCapability Shader
%1 = OpExtInstImport "GLSL.std.450"
OpMemoryModel Logical GLSL450
OpEntryPoint Fragment %2 "main"
OpExecutionMode %2 OriginUpperLeft
OpSource ESSL 310
OpName %2 "main"
%3 = OpTypeVoid
%4 = OpTypeFunction %3
%5 = OpTypeInt 32 1
%6 = OpTypePointer Function %5
%7 = OpTypeBool
%8 = OpConstantTrue %7
%2 = OpFunction %3 None %4
%9 = OpLabel
OpSelectionMerge %10 None
OpBranchConditional %8 %10 %10
%10 = OpLabel
OpReturn
OpFunctionEnd
)";
const auto env = SPV_ENV_UNIVERSAL_1_3;
const auto context = BuildModule(env, nullptr, shader, kReduceAssembleOption);
auto ops =
RemoveSelectionReductionOpportunityFinder().GetAvailableOpportunities(
context.get());
ASSERT_EQ(1, ops.size());
ASSERT_TRUE(ops[0]->PreconditionHolds());
ops[0]->TryToApply();
CheckValid(env, context.get());
std::string after = R"(
OpCapability Shader
%1 = OpExtInstImport "GLSL.std.450"
OpMemoryModel Logical GLSL450
OpEntryPoint Fragment %2 "main"
OpExecutionMode %2 OriginUpperLeft
OpSource ESSL 310
OpName %2 "main"
%3 = OpTypeVoid
%4 = OpTypeFunction %3
%5 = OpTypeInt 32 1
%6 = OpTypePointer Function %5
%7 = OpTypeBool
%8 = OpConstantTrue %7
%2 = OpFunction %3 None %4
%9 = OpLabel
OpBranchConditional %8 %10 %10
%10 = OpLabel
OpReturn
OpFunctionEnd
)";
CheckEqual(env, after, context.get());
ops = RemoveSelectionReductionOpportunityFinder().GetAvailableOpportunities(
context.get());
ASSERT_EQ(0, ops.size());
}
TEST(RemoveSelectionTest, NoOpportunityBecauseDifferentTargetBlocksOneMerge) {
// A test with the following structure. The OpSelectionMerge instruction
// should NOT be removed.
//
// header
// | |
// | block
// | |
// merge
std::string shader = R"(
OpCapability Shader
%1 = OpExtInstImport "GLSL.std.450"
OpMemoryModel Logical GLSL450
OpEntryPoint Fragment %2 "main"
OpExecutionMode %2 OriginUpperLeft
OpSource ESSL 310
OpName %2 "main"
%3 = OpTypeVoid
%4 = OpTypeFunction %3
%5 = OpTypeInt 32 1
%6 = OpTypePointer Function %5
%7 = OpTypeBool
%8 = OpConstantTrue %7
%2 = OpFunction %3 None %4
%9 = OpLabel
OpSelectionMerge %10 None
OpBranchConditional %8 %10 %11
%11 = OpLabel
OpBranch %10
%10 = OpLabel
OpReturn
OpFunctionEnd
)";
const auto env = SPV_ENV_UNIVERSAL_1_3;
const auto context = BuildModule(env, nullptr, shader, kReduceAssembleOption);
auto ops =
RemoveSelectionReductionOpportunityFinder().GetAvailableOpportunities(
context.get());
ASSERT_EQ(0, ops.size());
}
TEST(RemoveSelectionTest, NoOpportunityBecauseDifferentTargetBlocks) {
// A test with the following structure. The OpSelectionMerge instruction
// should NOT be removed.
//
// header
// | |
// b b
// | |
// merge
std::string shader = R"(
OpCapability Shader
%1 = OpExtInstImport "GLSL.std.450"
OpMemoryModel Logical GLSL450
OpEntryPoint Fragment %2 "main"
OpExecutionMode %2 OriginUpperLeft
OpSource ESSL 310
OpName %2 "main"
%3 = OpTypeVoid
%4 = OpTypeFunction %3
%5 = OpTypeInt 32 1
%6 = OpTypePointer Function %5
%7 = OpTypeBool
%8 = OpConstantTrue %7
%2 = OpFunction %3 None %4
%9 = OpLabel
OpSelectionMerge %10 None
OpBranchConditional %8 %11 %12
%11 = OpLabel
OpBranch %10
%12 = OpLabel
OpBranch %10
%10 = OpLabel
OpReturn
OpFunctionEnd
)";
const auto env = SPV_ENV_UNIVERSAL_1_3;
const auto context = BuildModule(env, nullptr, shader, kReduceAssembleOption);
auto ops =
RemoveSelectionReductionOpportunityFinder().GetAvailableOpportunities(
context.get());
ASSERT_EQ(0, ops.size());
}
TEST(RemoveSelectionTest, NoOpportunityBecauseMergeUsed) {
// A test with the following structure. The OpSelectionMerge instruction
// should NOT be removed.
//
// header
// ||
// block
// | |
// | block
// | |
// merge
std::string shader = R"(
OpCapability Shader
%1 = OpExtInstImport "GLSL.std.450"
OpMemoryModel Logical GLSL450
OpEntryPoint Fragment %2 "main"
OpExecutionMode %2 OriginUpperLeft
OpSource ESSL 310
OpName %2 "main"
%3 = OpTypeVoid
%4 = OpTypeFunction %3
%5 = OpTypeInt 32 1
%6 = OpTypePointer Function %5
%7 = OpTypeBool
%8 = OpConstantTrue %7
%2 = OpFunction %3 None %4
%9 = OpLabel
OpSelectionMerge %10 None
OpBranchConditional %8 %11 %12
%11 = OpLabel
OpBranchConditional %8 %10 %12
%12 = OpLabel
OpBranch %10
%10 = OpLabel
OpReturn
OpFunctionEnd
)";
const auto env = SPV_ENV_UNIVERSAL_1_3;
const auto context = BuildModule(env, nullptr, shader, kReduceAssembleOption);
auto ops =
RemoveSelectionReductionOpportunityFinder().GetAvailableOpportunities(
context.get());
ASSERT_EQ(0, ops.size());
}
TEST(RemoveSelectionTest, OpportunityBecauseLoopMergeUsed) {
// A test with the following structure. The OpSelectionMerge instruction
// should be removed.
//
// loop header
// |
// |
// s.header
// ||
// block
// | |
// | |
// | | ^ (to loop header)
// s.merge | |
// | / loop continue target (unreachable)
// loop merge
//
//
// which becomes:
//
// loop header
// |
// |
// block
// ||
// block
// | |
// | |
// | | ^ (to loop header)
// block | |
// | / loop continue target (unreachable)
// loop merge
std::string shader = R"(
OpCapability Shader
%1 = OpExtInstImport "GLSL.std.450"
OpMemoryModel Logical GLSL450
OpEntryPoint Fragment %2 "main"
OpExecutionMode %2 OriginUpperLeft
OpSource ESSL 310
OpName %2 "main"
%3 = OpTypeVoid
%4 = OpTypeFunction %3
%5 = OpTypeInt 32 1
%6 = OpTypePointer Function %5
%7 = OpTypeBool
%8 = OpConstantTrue %7
%2 = OpFunction %3 None %4
%9 = OpLabel
OpBranch %10
%10 = OpLabel
OpLoopMerge %11 %12 None
OpBranch %13
%13 = OpLabel
OpSelectionMerge %14 None
OpBranchConditional %8 %15 %15
%15 = OpLabel
OpBranchConditional %8 %14 %11
%14 = OpLabel
OpBranch %11
%12 = OpLabel
OpBranch %10
%11 = OpLabel
OpReturn
OpFunctionEnd
)";
const auto env = SPV_ENV_UNIVERSAL_1_3;
const auto context = BuildModule(env, nullptr, shader, kReduceAssembleOption);
CheckValid(env, context.get());
auto ops =
RemoveSelectionReductionOpportunityFinder().GetAvailableOpportunities(
context.get());
ASSERT_EQ(1, ops.size());
ASSERT_TRUE(ops[0]->PreconditionHolds());
ops[0]->TryToApply();
CheckValid(env, context.get());
std::string after = R"(
OpCapability Shader
%1 = OpExtInstImport "GLSL.std.450"
OpMemoryModel Logical GLSL450
OpEntryPoint Fragment %2 "main"
OpExecutionMode %2 OriginUpperLeft
OpSource ESSL 310
OpName %2 "main"
%3 = OpTypeVoid
%4 = OpTypeFunction %3
%5 = OpTypeInt 32 1
%6 = OpTypePointer Function %5
%7 = OpTypeBool
%8 = OpConstantTrue %7
%2 = OpFunction %3 None %4
%9 = OpLabel
OpBranch %10
%10 = OpLabel
OpLoopMerge %11 %12 None
OpBranch %13
%13 = OpLabel
OpBranchConditional %8 %15 %15
%15 = OpLabel
OpBranchConditional %8 %14 %11
%14 = OpLabel
OpBranch %11
%12 = OpLabel
OpBranch %10
%11 = OpLabel
OpReturn
OpFunctionEnd
)";
CheckEqual(env, after, context.get());
ops = RemoveSelectionReductionOpportunityFinder().GetAvailableOpportunities(
context.get());
ASSERT_EQ(0, ops.size());
}
TEST(RemoveSelectionTest, OpportunityBecauseLoopContinueUsed) {
// A test with the following structure. The OpSelectionMerge instruction
// should be removed.
//
// loop header
// |
// |
// s.header
// ||
// block
// | |
// | |
// | | ^ (to loop header)
// s.merge | |
// | loop continue target
// loop merge
//
//
// which becomes:
//
// loop header
// |
// |
// block
// ||
// block
// | |
// | |
// | | ^ (to loop header)
// block | |
// | loop continue target
// loop merge
std::string shader = R"(
OpCapability Shader
%1 = OpExtInstImport "GLSL.std.450"
OpMemoryModel Logical GLSL450
OpEntryPoint Fragment %2 "main"
OpExecutionMode %2 OriginUpperLeft
OpSource ESSL 310
OpName %2 "main"
%3 = OpTypeVoid
%4 = OpTypeFunction %3
%5 = OpTypeInt 32 1
%6 = OpTypePointer Function %5
%7 = OpTypeBool
%8 = OpConstantTrue %7
%2 = OpFunction %3 None %4
%9 = OpLabel
OpBranch %10
%10 = OpLabel
OpLoopMerge %11 %12 None
OpBranch %13
%13 = OpLabel
OpSelectionMerge %14 None
OpBranchConditional %8 %15 %15
%15 = OpLabel
OpBranchConditional %8 %14 %12
%14 = OpLabel
OpBranch %11
%12 = OpLabel
OpBranch %10
%11 = OpLabel
OpReturn
OpFunctionEnd
)";
const auto env = SPV_ENV_UNIVERSAL_1_3;
const auto context = BuildModule(env, nullptr, shader, kReduceAssembleOption);
CheckValid(env, context.get());
auto ops =
RemoveSelectionReductionOpportunityFinder().GetAvailableOpportunities(
context.get());
ASSERT_EQ(1, ops.size());
ASSERT_TRUE(ops[0]->PreconditionHolds());
ops[0]->TryToApply();
CheckValid(env, context.get());
std::string after = R"(
OpCapability Shader
%1 = OpExtInstImport "GLSL.std.450"
OpMemoryModel Logical GLSL450
OpEntryPoint Fragment %2 "main"
OpExecutionMode %2 OriginUpperLeft
OpSource ESSL 310
OpName %2 "main"
%3 = OpTypeVoid
%4 = OpTypeFunction %3
%5 = OpTypeInt 32 1
%6 = OpTypePointer Function %5
%7 = OpTypeBool
%8 = OpConstantTrue %7
%2 = OpFunction %3 None %4
%9 = OpLabel
OpBranch %10
%10 = OpLabel
OpLoopMerge %11 %12 None
OpBranch %13
%13 = OpLabel
OpBranchConditional %8 %15 %15
%15 = OpLabel
OpBranchConditional %8 %14 %12
%14 = OpLabel
OpBranch %11
%12 = OpLabel
OpBranch %10
%11 = OpLabel
OpReturn
OpFunctionEnd
)";
CheckEqual(env, after, context.get());
ops = RemoveSelectionReductionOpportunityFinder().GetAvailableOpportunities(
context.get());
ASSERT_EQ(0, ops.size());
}
} // namespace
} // namespace reduce
} // namespace spvtools