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310 lines
10 KiB
310 lines
10 KiB
/*
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* Copyright (C) 2015 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "instruction_simplifier_arm.h"
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#include "code_generator.h"
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#include "common_arm.h"
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#include "instruction_simplifier_shared.h"
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#include "mirror/array-inl.h"
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#include "mirror/string.h"
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#include "nodes.h"
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namespace art {
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using helpers::CanFitInShifterOperand;
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using helpers::HasShifterOperand;
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using helpers::IsSubRightSubLeftShl;
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namespace arm {
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class InstructionSimplifierArmVisitor : public HGraphVisitor {
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public:
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InstructionSimplifierArmVisitor(HGraph* graph, OptimizingCompilerStats* stats)
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: HGraphVisitor(graph), stats_(stats) {}
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private:
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void RecordSimplification() {
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MaybeRecordStat(stats_, MethodCompilationStat::kInstructionSimplificationsArch);
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}
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bool TryMergeIntoUsersShifterOperand(HInstruction* instruction);
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bool TryMergeIntoShifterOperand(HInstruction* use, HInstruction* bitfield_op, bool do_merge);
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bool CanMergeIntoShifterOperand(HInstruction* use, HInstruction* bitfield_op) {
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return TryMergeIntoShifterOperand(use, bitfield_op, /* do_merge= */ false);
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}
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bool MergeIntoShifterOperand(HInstruction* use, HInstruction* bitfield_op) {
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DCHECK(CanMergeIntoShifterOperand(use, bitfield_op));
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return TryMergeIntoShifterOperand(use, bitfield_op, /* do_merge= */ true);
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}
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/**
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* This simplifier uses a special-purpose BB visitor.
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* (1) No need to visit Phi nodes.
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* (2) Since statements can be removed in a "forward" fashion,
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* the visitor should test if each statement is still there.
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*/
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void VisitBasicBlock(HBasicBlock* block) override {
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// TODO: fragile iteration, provide more robust iterators?
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for (HInstructionIterator it(block->GetInstructions()); !it.Done(); it.Advance()) {
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HInstruction* instruction = it.Current();
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if (instruction->IsInBlock()) {
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instruction->Accept(this);
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}
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}
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}
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void VisitAnd(HAnd* instruction) override;
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void VisitArrayGet(HArrayGet* instruction) override;
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void VisitArraySet(HArraySet* instruction) override;
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void VisitMul(HMul* instruction) override;
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void VisitOr(HOr* instruction) override;
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void VisitShl(HShl* instruction) override;
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void VisitShr(HShr* instruction) override;
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void VisitSub(HSub* instruction) override;
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void VisitTypeConversion(HTypeConversion* instruction) override;
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void VisitUShr(HUShr* instruction) override;
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OptimizingCompilerStats* stats_;
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};
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bool InstructionSimplifierArmVisitor::TryMergeIntoShifterOperand(HInstruction* use,
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HInstruction* bitfield_op,
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bool do_merge) {
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DCHECK(HasShifterOperand(use, InstructionSet::kArm));
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DCHECK(use->IsBinaryOperation());
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DCHECK(CanFitInShifterOperand(bitfield_op));
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DCHECK(!bitfield_op->HasEnvironmentUses());
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DataType::Type type = use->GetType();
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if (type != DataType::Type::kInt32 && type != DataType::Type::kInt64) {
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return false;
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}
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HInstruction* left = use->InputAt(0);
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HInstruction* right = use->InputAt(1);
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DCHECK(left == bitfield_op || right == bitfield_op);
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if (left == right) {
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// TODO: Handle special transformations in this situation?
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// For example should we transform `(x << 1) + (x << 1)` into `(x << 2)`?
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// Or should this be part of a separate transformation logic?
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return false;
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}
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bool is_commutative = use->AsBinaryOperation()->IsCommutative();
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HInstruction* other_input;
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if (bitfield_op == right) {
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other_input = left;
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} else {
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if (is_commutative) {
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other_input = right;
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} else {
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return false;
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}
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}
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HDataProcWithShifterOp::OpKind op_kind;
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int shift_amount = 0;
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HDataProcWithShifterOp::GetOpInfoFromInstruction(bitfield_op, &op_kind, &shift_amount);
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shift_amount &= use->GetType() == DataType::Type::kInt32
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? kMaxIntShiftDistance
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: kMaxLongShiftDistance;
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if (HDataProcWithShifterOp::IsExtensionOp(op_kind)) {
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if (!use->IsAdd() && (!use->IsSub() || use->GetType() != DataType::Type::kInt64)) {
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return false;
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}
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// Shift by 1 is a special case that results in the same number and type of instructions
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// as this simplification, but potentially shorter code.
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} else if (type == DataType::Type::kInt64 && shift_amount == 1) {
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return false;
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}
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if (do_merge) {
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HDataProcWithShifterOp* alu_with_op =
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new (GetGraph()->GetAllocator()) HDataProcWithShifterOp(use,
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other_input,
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bitfield_op->InputAt(0),
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op_kind,
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shift_amount,
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use->GetDexPc());
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use->GetBlock()->ReplaceAndRemoveInstructionWith(use, alu_with_op);
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if (bitfield_op->GetUses().empty()) {
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bitfield_op->GetBlock()->RemoveInstruction(bitfield_op);
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}
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RecordSimplification();
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}
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return true;
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}
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// Merge a bitfield move instruction into its uses if it can be merged in all of them.
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bool InstructionSimplifierArmVisitor::TryMergeIntoUsersShifterOperand(HInstruction* bitfield_op) {
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DCHECK(CanFitInShifterOperand(bitfield_op));
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if (bitfield_op->HasEnvironmentUses()) {
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return false;
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}
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const HUseList<HInstruction*>& uses = bitfield_op->GetUses();
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// Check whether we can merge the instruction in all its users' shifter operand.
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for (const HUseListNode<HInstruction*>& use : uses) {
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HInstruction* user = use.GetUser();
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if (!HasShifterOperand(user, InstructionSet::kArm)) {
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return false;
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}
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if (!CanMergeIntoShifterOperand(user, bitfield_op)) {
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return false;
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}
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}
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// Merge the instruction into its uses.
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for (auto it = uses.begin(), end = uses.end(); it != end; /* ++it below */) {
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HInstruction* user = it->GetUser();
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// Increment `it` now because `*it` will disappear thanks to MergeIntoShifterOperand().
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++it;
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bool merged = MergeIntoShifterOperand(user, bitfield_op);
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DCHECK(merged);
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}
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return true;
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}
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void InstructionSimplifierArmVisitor::VisitAnd(HAnd* instruction) {
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if (TryMergeNegatedInput(instruction)) {
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RecordSimplification();
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}
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}
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void InstructionSimplifierArmVisitor::VisitArrayGet(HArrayGet* instruction) {
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size_t data_offset = CodeGenerator::GetArrayDataOffset(instruction);
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DataType::Type type = instruction->GetType();
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// TODO: Implement reading (length + compression) for String compression feature from
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// negative offset (count_offset - data_offset). Thumb2Assembler (now removed) did
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// not support T4 encoding of "LDR (immediate)", but ArmVIXLMacroAssembler might.
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// Don't move array pointer if it is charAt because we need to take the count first.
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if (mirror::kUseStringCompression && instruction->IsStringCharAt()) {
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return;
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}
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// TODO: Support intermediate address for object arrays on arm.
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if (type == DataType::Type::kReference) {
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return;
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}
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if (type == DataType::Type::kInt64
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|| type == DataType::Type::kFloat32
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|| type == DataType::Type::kFloat64) {
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// T32 doesn't support ShiftedRegOffset mem address mode for these types
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// to enable optimization.
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return;
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}
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if (TryExtractArrayAccessAddress(instruction,
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instruction->GetArray(),
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instruction->GetIndex(),
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data_offset)) {
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RecordSimplification();
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}
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}
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void InstructionSimplifierArmVisitor::VisitArraySet(HArraySet* instruction) {
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size_t access_size = DataType::Size(instruction->GetComponentType());
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size_t data_offset = mirror::Array::DataOffset(access_size).Uint32Value();
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DataType::Type type = instruction->GetComponentType();
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if (type == DataType::Type::kInt64
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|| type == DataType::Type::kFloat32
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|| type == DataType::Type::kFloat64) {
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// T32 doesn't support ShiftedRegOffset mem address mode for these types
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// to enable optimization.
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return;
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}
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if (TryExtractArrayAccessAddress(instruction,
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instruction->GetArray(),
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instruction->GetIndex(),
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data_offset)) {
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RecordSimplification();
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}
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}
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void InstructionSimplifierArmVisitor::VisitMul(HMul* instruction) {
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if (TryCombineMultiplyAccumulate(instruction, InstructionSet::kArm)) {
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RecordSimplification();
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}
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}
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void InstructionSimplifierArmVisitor::VisitOr(HOr* instruction) {
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if (TryMergeNegatedInput(instruction)) {
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RecordSimplification();
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}
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}
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void InstructionSimplifierArmVisitor::VisitShl(HShl* instruction) {
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if (instruction->InputAt(1)->IsConstant()) {
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TryMergeIntoUsersShifterOperand(instruction);
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}
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}
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void InstructionSimplifierArmVisitor::VisitShr(HShr* instruction) {
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if (instruction->InputAt(1)->IsConstant()) {
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TryMergeIntoUsersShifterOperand(instruction);
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}
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}
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void InstructionSimplifierArmVisitor::VisitSub(HSub* instruction) {
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if (IsSubRightSubLeftShl(instruction)) {
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HInstruction* shl = instruction->GetRight()->InputAt(0);
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if (shl->InputAt(1)->IsConstant() && TryReplaceSubSubWithSubAdd(instruction)) {
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TryMergeIntoUsersShifterOperand(shl);
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}
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}
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}
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void InstructionSimplifierArmVisitor::VisitTypeConversion(HTypeConversion* instruction) {
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DataType::Type result_type = instruction->GetResultType();
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DataType::Type input_type = instruction->GetInputType();
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if (input_type == result_type) {
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// We let the arch-independent code handle this.
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return;
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}
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if (DataType::IsIntegralType(result_type) && DataType::IsIntegralType(input_type)) {
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TryMergeIntoUsersShifterOperand(instruction);
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}
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}
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void InstructionSimplifierArmVisitor::VisitUShr(HUShr* instruction) {
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if (instruction->InputAt(1)->IsConstant()) {
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TryMergeIntoUsersShifterOperand(instruction);
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}
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}
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bool InstructionSimplifierArm::Run() {
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InstructionSimplifierArmVisitor visitor(graph_, stats_);
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visitor.VisitReversePostOrder();
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return true;
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}
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} // namespace arm
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} // namespace art
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