SPIRV-Tools/source/reduce/remove_block_reduction_opportunity.cpp
Alastair Donaldson de7d57984d
spirv-reduce: Refactoring (#3793)
Avoids the use of "using" in favour of explicit qualification, to be
consistent with spirv-fuzz. Fixes indentation in a TODO comment.
Addresses and removes two existing TODO comments by moving some helper
functionality into reduction_util.

Related issue: #2184.
2020-09-10 22:03:40 +01:00

55 lines
1.8 KiB
C++

// 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_block_reduction_opportunity.h"
#include "source/opt/ir_context.h"
namespace spvtools {
namespace reduce {
RemoveBlockReductionOpportunity::RemoveBlockReductionOpportunity(
opt::Function* function, opt::BasicBlock* block)
: function_(function), block_(block) {
// precondition:
assert(block_->begin() != block_->end() &&
block_->begin()->context()->get_def_use_mgr()->NumUsers(
block_->id()) == 0 &&
"RemoveBlockReductionOpportunity block must have 0 references");
}
bool RemoveBlockReductionOpportunity::PreconditionHolds() {
// Removing other blocks cannot disable this opportunity.
return true;
}
void RemoveBlockReductionOpportunity::Apply() {
// We need an iterator pointing to the block, hence the loop.
for (auto bi = function_->begin(); bi != function_->end(); ++bi) {
if (bi->id() == block_->id()) {
bi->KillAllInsts(true);
bi.Erase();
// Block removal changes the function, but we don't use analyses, so no
// need to invalidate them.
return;
}
}
assert(false &&
"Unreachable: we should have found a block with the desired id.");
}
} // namespace reduce
} // namespace spvtools