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// 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/simple_conditional_branch_to_branch_reduction_opportunity.h"
#include "source/reduce/reduction_util.h"
namespace spvtools {
namespace reduce {
SimpleConditionalBranchToBranchReductionOpportunity::
SimpleConditionalBranchToBranchReductionOpportunity(
opt::Instruction* conditional_branch_instruction)
: conditional_branch_instruction_(conditional_branch_instruction) {}
bool SimpleConditionalBranchToBranchReductionOpportunity::PreconditionHolds() {
// We find at most one opportunity per conditional branch and simplifying
// another branch cannot disable this opportunity.
return true;
}
void SimpleConditionalBranchToBranchReductionOpportunity::Apply() {
assert(conditional_branch_instruction_->opcode() ==
spv::Op::OpBranchConditional &&
"SimpleConditionalBranchToBranchReductionOpportunity: branch was not "
"a conditional branch");
assert(conditional_branch_instruction_->GetSingleWordInOperand(
kTrueBranchOperandIndex) ==
conditional_branch_instruction_->GetSingleWordInOperand(
kFalseBranchOperandIndex) &&
"SimpleConditionalBranchToBranchReductionOpportunity: branch was not "
"simple");
// OpBranchConditional %condition %block_id %block_id ...
// ->
// OpBranch %block_id
conditional_branch_instruction_->SetOpcode(spv::Op::OpBranch);
conditional_branch_instruction_->ReplaceOperands(
{{SPV_OPERAND_TYPE_ID,
{conditional_branch_instruction_->GetSingleWordInOperand(
kTrueBranchOperandIndex)}}});
conditional_branch_instruction_->context()->InvalidateAnalysesExceptFor(
opt::IRContext::kAnalysisNone);
}
} // namespace reduce
} // namespace spvtools