From bf9cd7ba2118a75f5aa9b56241c4d5fa00dedeb8 Mon Sep 17 00:00:00 2001 From: Roland Levillain Date: Tue, 30 Sep 2014 16:15:14 +0100 Subject: Introduce a class to implement optimization passes. - Add art::HOptimization. - Rename art::ConstantPropagation to art::HConstantFolding in compiler/optimizing/constant_folding.h to avoid name clashes with a class of the same name in compiler/dex/post_opt_passes.h. - Rename art::DeadCodeElimination to art::HDeadCodeElimination for consistency reasons. - Have art::HDeadCodeElimination and art::HConstantFolding derive from art::HOptimization. - Start to use these optimizations in art:OptimizingCompiler::TryCompile. Change-Id: Iaab350c122d87b2333b3760312b15c0592d7e010 --- compiler/optimizing/constant_folding.cc | 47 +++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) create mode 100644 compiler/optimizing/constant_folding.cc (limited to 'compiler/optimizing/constant_folding.cc') diff --git a/compiler/optimizing/constant_folding.cc b/compiler/optimizing/constant_folding.cc new file mode 100644 index 0000000000..0b3ad9809f --- /dev/null +++ b/compiler/optimizing/constant_folding.cc @@ -0,0 +1,47 @@ +/* + * Copyright (C) 2014 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 "constant_folding.h" + +namespace art { + +void HConstantFolding::Run() { + // Process basic blocks in reverse post-order in the dominator tree, + // so that an instruction turned into a constant, used as input of + // another instruction, may possibly be used to turn that second + // instruction into a constant as well. + for (HReversePostOrderIterator it(*graph_); !it.Done(); it.Advance()) { + HBasicBlock* block = it.Current(); + // Traverse this block's instructions in (forward) order and + // replace the ones that can be statically evaluated by a + // compile-time counterpart. + for (HInstructionIterator it(block->GetInstructions()); + !it.Done(); it.Advance()) { + HInstruction* inst = it.Current(); + // Constant folding: replace `c <- a op b' with a compile-time + // evaluation of `a op b' if `a' and `b' are constant. + if (inst->IsBinaryOperation()) { + HConstant* constant = + inst->AsBinaryOperation()->TryStaticEvaluation(graph_->GetArena()); + if (constant != nullptr) { + inst->GetBlock()->ReplaceAndRemoveInstructionWith(inst, constant); + } + } + } + } +} + +} // namespace art -- cgit v1.2.3-59-g8ed1b