/*
* Copyright (C) 2015 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 "instruction_simplifier_arm64.h"
#include "common_arm64.h"
#include "instruction_simplifier_shared.h"
#include "mirror/array-inl.h"
namespace art {
namespace arm64 {
using helpers::CanFitInShifterOperand;
using helpers::HasShifterOperand;
using helpers::ShifterOperandSupportsExtension;
void InstructionSimplifierArm64Visitor::TryExtractArrayAccessAddress(HInstruction* access,
HInstruction* array,
HInstruction* index,
int access_size) {
if (kEmitCompilerReadBarrier) {
// The read barrier instrumentation does not support the
// HArm64IntermediateAddress instruction yet.
//
// TODO: Handle this case properly in the ARM64 code generator and
// re-enable this optimization; otherwise, remove this TODO.
// b/26601270
return;
}
if (index->IsConstant() ||
(index->IsBoundsCheck() && index->AsBoundsCheck()->GetIndex()->IsConstant())) {
// When the index is a constant all the addressing can be fitted in the
// memory access instruction, so do not split the access.
return;
}
if (access->IsArraySet() &&
access->AsArraySet()->GetValue()->GetType() == Primitive::kPrimNot) {
// The access may require a runtime call or the original array pointer.
return;
}
// Proceed to extract the base address computation.
ArenaAllocator* arena = GetGraph()->GetArena();
HIntConstant* offset =
GetGraph()->GetIntConstant(mirror::Array::DataOffset(access_size).Uint32Value());
HArm64IntermediateAddress* address =
new (arena) HArm64IntermediateAddress(array, offset, kNoDexPc);
address->SetReferenceTypeInfo(array->GetReferenceTypeInfo());
access->GetBlock()->InsertInstructionBefore(address, access);
access->ReplaceInput(address, 0);
// Both instructions must depend on GC to prevent any instruction that can
// trigger GC to be inserted between the two.
access->AddSideEffects(SideEffects::DependsOnGC());
DCHECK(address->GetSideEffects().Includes(SideEffects::DependsOnGC()));
DCHECK(access->GetSideEffects().Includes(SideEffects::DependsOnGC()));
// TODO: Code generation for HArrayGet and HArraySet will check whether the input address
// is an HArm64IntermediateAddress and generate appropriate code.
// We would like to replace the `HArrayGet` and `HArraySet` with custom instructions (maybe
// `HArm64Load` and `HArm64Store`). We defer these changes because these new instructions would
// not bring any advantages yet.
// Also see the comments in
// `InstructionCodeGeneratorARM64::VisitArrayGet()` and
// `InstructionCodeGeneratorARM64::VisitArraySet()`.
RecordSimplification();
}
bool InstructionSimplifierArm64Visitor::TryMergeIntoShifterOperand(HInstruction* use,
HInstruction* bitfield_op,
bool do_merge) {
DCHECK(HasShifterOperand(use));
DCHECK(use->IsBinaryOperation() || use->IsNeg());
DCHECK(CanFitInShifterOperand(bitfield_op));
DCHECK(!bitfield_op->HasEnvironmentUses());
Primitive::Type type = use->GetType();
if (type != Primitive::kPrimInt && type != Primitive::kPrimLong) {
return false;
}
HInstruction* left;
HInstruction* right;
if (use->IsBinaryOperation()) {
left = use->InputAt(0);
right = use->InputAt(1);
} else {
DCHECK(use->IsNeg());
right = use->AsNeg()->InputAt(0);
left = GetGraph()->GetConstant(right->GetType(), 0);
}
DCHECK(left == bitfield_op || right == bitfield_op);
if (left == right) {
// TODO: Handle special transformations in this situation?
// For example should we transform `(x << 1) + (x << 1)` into `(x << 2)`?
// Or should this be part of a separate transformation logic?
return false;
}
bool is_commutative = use->IsBinaryOperation() && use->AsBinaryOperation()->IsCommutative();
HInstruction* other_input;
if (bitfield_op == right) {
other_input = left;
} else {
if (is_commutative) {
other_input = right;
} else {
return false;
}
}
HArm64DataProcWithShifterOp::OpKind op_kind;
int shift_amount = 0;
HArm64DataProcWithShifterOp::GetOpInfoFromInstruction(bitfield_op, &op_kind, &shift_amount);
if (HArm64DataProcWithShifterOp::IsExtensionOp(op_kind) &&
!ShifterOperandSupportsExtension(use)) {
return false;
}
if (do_merge) {
HArm64DataProcWithShifterOp* alu_with_op =
new (GetGraph()->GetArena()) HArm64DataProcWithShifterOp(use,
other_input,
bitfield_op->InputAt(0),
op_kind,
shift_amount,
use->GetDexPc());
use->GetBlock()->ReplaceAndRemoveInstructionWith(use, alu_with_op);
if (bitfield_op->GetUses().empty()) {
bitfield_op->GetBlock()->RemoveInstruction(bitfield_op);
}
RecordSimplification();
}
return true;
}
// Merge a bitfield move instruction into its uses if it can be merged in all of them.
bool InstructionSimplifierArm64Visitor::TryMergeIntoUsersShifterOperand(HInstruction* bitfield_op) {
DCHECK(CanFitInShifterOperand(bitfield_op));
if (bitfield_op->HasEnvironmentUses()) {
return false;
}
const HUseList<HInstruction*>& uses = bitfield_op->GetUses();
// Check whether we can merge the instruction in all its users' shifter operand.
for (const HUseListNode<HInstruction*>& use : uses) {
HInstruction* user = use.GetUser();
if (!HasShifterOperand(user)) {
return false;
}
if (!CanMergeIntoShifterOperand(user, bitfield_op)) {
return false;
}
}
// Merge the instruction into its uses.
for (auto it = uses.begin(), end = uses.end(); it != end; /* ++it below */) {
HInstruction* user = it->GetUser();
// Increment `it` now because `*it` will disappear thanks to MergeIntoShifterOperand().
++it;
bool merged = MergeIntoShifterOperand(user, bitfield_op);
DCHECK(merged);
}
return true;
}
void InstructionSimplifierArm64Visitor::VisitAnd(HAnd* instruction) {
if (TryMergeNegatedInput(instruction)) {
RecordSimplification();
}
}
void InstructionSimplifierArm64Visitor::VisitArrayGet(HArrayGet* instruction) {
TryExtractArrayAccessAddress(instruction,
instruction->GetArray(),
instruction->GetIndex(),
Primitive::ComponentSize(instruction->GetType()));
}
void InstructionSimplifierArm64Visitor::VisitArraySet(HArraySet* instruction) {
TryExtractArrayAccessAddress(instruction,
instruction->GetArray(),
instruction->GetIndex(),
Primitive::ComponentSize(instruction->GetComponentType()));
}
void InstructionSimplifierArm64Visitor::VisitMul(HMul* instruction) {
if (TryCombineMultiplyAccumulate(instruction, kArm64)) {
RecordSimplification();
}
}
void InstructionSimplifierArm64Visitor::VisitOr(HOr* instruction) {
if (TryMergeNegatedInput(instruction)) {
RecordSimplification();
}
}
void InstructionSimplifierArm64Visitor::VisitShl(HShl* instruction) {
if (instruction->InputAt(1)->IsConstant()) {
TryMergeIntoUsersShifterOperand(instruction);
}
}
void InstructionSimplifierArm64Visitor::VisitShr(HShr* instruction) {
if (instruction->InputAt(1)->IsConstant()) {
TryMergeIntoUsersShifterOperand(instruction);
}
}
void InstructionSimplifierArm64Visitor::VisitTypeConversion(HTypeConversion* instruction) {
Primitive::Type result_type = instruction->GetResultType();
Primitive::Type input_type = instruction->GetInputType();
if (input_type == result_type) {
// We let the arch-independent code handle this.
return;
}
if (Primitive::IsIntegralType(result_type) && Primitive::IsIntegralType(input_type)) {
TryMergeIntoUsersShifterOperand(instruction);
}
}
void InstructionSimplifierArm64Visitor::VisitUShr(HUShr* instruction) {
if (instruction->InputAt(1)->IsConstant()) {
TryMergeIntoUsersShifterOperand(instruction);
}
}
void InstructionSimplifierArm64Visitor::VisitXor(HXor* instruction) {
if (TryMergeNegatedInput(instruction)) {
RecordSimplification();
}
}
} // namespace arm64
} // namespace art