1788 lines
69 KiB
C++
1788 lines
69 KiB
C++
/*
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* Copyright (C) 2016 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 "loop_optimization.h"
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#include "arch/instruction_set.h"
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#include "arch/arm/instruction_set_features_arm.h"
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#include "arch/arm64/instruction_set_features_arm64.h"
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#include "arch/mips/instruction_set_features_mips.h"
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#include "arch/mips64/instruction_set_features_mips64.h"
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#include "arch/x86/instruction_set_features_x86.h"
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#include "arch/x86_64/instruction_set_features_x86_64.h"
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#include "driver/compiler_driver.h"
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#include "linear_order.h"
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namespace art {
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// Enables vectorization (SIMDization) in the loop optimizer.
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static constexpr bool kEnableVectorization = true;
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// All current SIMD targets want 16-byte alignment.
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static constexpr size_t kAlignedBase = 16;
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// Remove the instruction from the graph. A bit more elaborate than the usual
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// instruction removal, since there may be a cycle in the use structure.
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static void RemoveFromCycle(HInstruction* instruction) {
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instruction->RemoveAsUserOfAllInputs();
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instruction->RemoveEnvironmentUsers();
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instruction->GetBlock()->RemoveInstructionOrPhi(instruction, /*ensure_safety=*/ false);
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}
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// Detect a goto block and sets succ to the single successor.
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static bool IsGotoBlock(HBasicBlock* block, /*out*/ HBasicBlock** succ) {
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if (block->GetPredecessors().size() == 1 &&
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block->GetSuccessors().size() == 1 &&
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block->IsSingleGoto()) {
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*succ = block->GetSingleSuccessor();
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return true;
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}
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return false;
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}
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// Detect an early exit loop.
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static bool IsEarlyExit(HLoopInformation* loop_info) {
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HBlocksInLoopReversePostOrderIterator it_loop(*loop_info);
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for (it_loop.Advance(); !it_loop.Done(); it_loop.Advance()) {
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for (HBasicBlock* successor : it_loop.Current()->GetSuccessors()) {
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if (!loop_info->Contains(*successor)) {
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return true;
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}
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}
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}
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return false;
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}
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// Detect a sign extension from the given type. Returns the promoted operand on success.
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static bool IsSignExtensionAndGet(HInstruction* instruction,
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Primitive::Type type,
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/*out*/ HInstruction** operand) {
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// Accept any already wider constant that would be handled properly by sign
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// extension when represented in the *width* of the given narrower data type
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// (the fact that char normally zero extends does not matter here).
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int64_t value = 0;
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if (IsInt64AndGet(instruction, /*out*/ &value)) {
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switch (type) {
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case Primitive::kPrimByte:
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if (std::numeric_limits<int8_t>::min() <= value &&
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std::numeric_limits<int8_t>::max() >= value) {
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*operand = instruction;
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return true;
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}
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return false;
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case Primitive::kPrimChar:
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case Primitive::kPrimShort:
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if (std::numeric_limits<int16_t>::min() <= value &&
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std::numeric_limits<int16_t>::max() <= value) {
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*operand = instruction;
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return true;
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}
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return false;
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default:
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return false;
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}
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}
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// An implicit widening conversion of a signed integer to an integral type sign-extends
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// the two's-complement representation of the integer value to fill the wider format.
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if (instruction->GetType() == type && (instruction->IsArrayGet() ||
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instruction->IsStaticFieldGet() ||
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instruction->IsInstanceFieldGet())) {
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switch (type) {
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case Primitive::kPrimByte:
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case Primitive::kPrimShort:
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*operand = instruction;
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return true;
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default:
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return false;
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}
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}
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// TODO: perhaps explicit conversions later too?
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// (this may return something different from instruction)
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return false;
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}
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// Detect a zero extension from the given type. Returns the promoted operand on success.
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static bool IsZeroExtensionAndGet(HInstruction* instruction,
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Primitive::Type type,
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/*out*/ HInstruction** operand) {
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// Accept any already wider constant that would be handled properly by zero
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// extension when represented in the *width* of the given narrower data type
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// (the fact that byte/short normally sign extend does not matter here).
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int64_t value = 0;
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if (IsInt64AndGet(instruction, /*out*/ &value)) {
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switch (type) {
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case Primitive::kPrimByte:
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if (std::numeric_limits<uint8_t>::min() <= value &&
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std::numeric_limits<uint8_t>::max() >= value) {
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*operand = instruction;
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return true;
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}
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return false;
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case Primitive::kPrimChar:
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case Primitive::kPrimShort:
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if (std::numeric_limits<uint16_t>::min() <= value &&
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std::numeric_limits<uint16_t>::max() <= value) {
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*operand = instruction;
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return true;
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}
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return false;
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default:
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return false;
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}
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}
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// An implicit widening conversion of a char to an integral type zero-extends
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// the representation of the char value to fill the wider format.
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if (instruction->GetType() == type && (instruction->IsArrayGet() ||
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instruction->IsStaticFieldGet() ||
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instruction->IsInstanceFieldGet())) {
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if (type == Primitive::kPrimChar) {
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*operand = instruction;
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return true;
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}
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}
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// A sign (or zero) extension followed by an explicit removal of just the
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// higher sign bits is equivalent to a zero extension of the underlying operand.
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if (instruction->IsAnd()) {
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int64_t mask = 0;
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HInstruction* a = instruction->InputAt(0);
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HInstruction* b = instruction->InputAt(1);
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// In (a & b) find (mask & b) or (a & mask) with sign or zero extension on the non-mask.
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if ((IsInt64AndGet(a, /*out*/ &mask) && (IsSignExtensionAndGet(b, type, /*out*/ operand) ||
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IsZeroExtensionAndGet(b, type, /*out*/ operand))) ||
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(IsInt64AndGet(b, /*out*/ &mask) && (IsSignExtensionAndGet(a, type, /*out*/ operand) ||
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IsZeroExtensionAndGet(a, type, /*out*/ operand)))) {
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switch ((*operand)->GetType()) {
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case Primitive::kPrimByte: return mask == std::numeric_limits<uint8_t>::max();
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case Primitive::kPrimChar:
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case Primitive::kPrimShort: return mask == std::numeric_limits<uint16_t>::max();
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default: return false;
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}
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}
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}
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// TODO: perhaps explicit conversions later too?
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return false;
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}
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// Detect situations with same-extension narrower operands.
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// Returns true on success and sets is_unsigned accordingly.
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static bool IsNarrowerOperands(HInstruction* a,
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HInstruction* b,
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Primitive::Type type,
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/*out*/ HInstruction** r,
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/*out*/ HInstruction** s,
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/*out*/ bool* is_unsigned) {
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if (IsSignExtensionAndGet(a, type, r) && IsSignExtensionAndGet(b, type, s)) {
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*is_unsigned = false;
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return true;
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} else if (IsZeroExtensionAndGet(a, type, r) && IsZeroExtensionAndGet(b, type, s)) {
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*is_unsigned = true;
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return true;
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}
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return false;
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}
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// As above, single operand.
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static bool IsNarrowerOperand(HInstruction* a,
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Primitive::Type type,
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/*out*/ HInstruction** r,
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/*out*/ bool* is_unsigned) {
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if (IsSignExtensionAndGet(a, type, r)) {
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*is_unsigned = false;
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return true;
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} else if (IsZeroExtensionAndGet(a, type, r)) {
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*is_unsigned = true;
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return true;
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}
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return false;
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}
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// Detect up to two instructions a and b, and an acccumulated constant c.
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static bool IsAddConstHelper(HInstruction* instruction,
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/*out*/ HInstruction** a,
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/*out*/ HInstruction** b,
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/*out*/ int64_t* c,
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int32_t depth) {
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static constexpr int32_t kMaxDepth = 8; // don't search too deep
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int64_t value = 0;
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if (IsInt64AndGet(instruction, &value)) {
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*c += value;
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return true;
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} else if (instruction->IsAdd() && depth <= kMaxDepth) {
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return IsAddConstHelper(instruction->InputAt(0), a, b, c, depth + 1) &&
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IsAddConstHelper(instruction->InputAt(1), a, b, c, depth + 1);
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} else if (*a == nullptr) {
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*a = instruction;
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return true;
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} else if (*b == nullptr) {
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*b = instruction;
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return true;
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}
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return false; // too many non-const operands
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}
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// Detect a + b + c for an optional constant c.
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static bool IsAddConst(HInstruction* instruction,
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/*out*/ HInstruction** a,
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/*out*/ HInstruction** b,
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/*out*/ int64_t* c) {
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if (instruction->IsAdd()) {
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// Try to find a + b and accumulated c.
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if (IsAddConstHelper(instruction->InputAt(0), a, b, c, /*depth*/ 0) &&
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IsAddConstHelper(instruction->InputAt(1), a, b, c, /*depth*/ 0) &&
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*b != nullptr) {
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return true;
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}
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// Found a + b.
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*a = instruction->InputAt(0);
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*b = instruction->InputAt(1);
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*c = 0;
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return true;
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}
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return false;
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}
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// Test vector restrictions.
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static bool HasVectorRestrictions(uint64_t restrictions, uint64_t tested) {
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return (restrictions & tested) != 0;
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}
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// Insert an instruction.
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static HInstruction* Insert(HBasicBlock* block, HInstruction* instruction) {
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DCHECK(block != nullptr);
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DCHECK(instruction != nullptr);
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block->InsertInstructionBefore(instruction, block->GetLastInstruction());
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return instruction;
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}
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//
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// Class methods.
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//
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HLoopOptimization::HLoopOptimization(HGraph* graph,
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CompilerDriver* compiler_driver,
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HInductionVarAnalysis* induction_analysis)
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: HOptimization(graph, kLoopOptimizationPassName),
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compiler_driver_(compiler_driver),
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induction_range_(induction_analysis),
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loop_allocator_(nullptr),
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global_allocator_(graph_->GetArena()),
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top_loop_(nullptr),
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last_loop_(nullptr),
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iset_(nullptr),
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induction_simplication_count_(0),
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simplified_(false),
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vector_length_(0),
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vector_refs_(nullptr),
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vector_peeling_candidate_(nullptr),
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vector_runtime_test_a_(nullptr),
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vector_runtime_test_b_(nullptr),
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vector_map_(nullptr) {
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}
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void HLoopOptimization::Run() {
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// Skip if there is no loop or the graph has try-catch/irreducible loops.
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// TODO: make this less of a sledgehammer.
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if (!graph_->HasLoops() || graph_->HasTryCatch() || graph_->HasIrreducibleLoops()) {
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return;
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}
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// Phase-local allocator that draws from the global pool. Since the allocator
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// itself resides on the stack, it is destructed on exiting Run(), which
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// implies its underlying memory is released immediately.
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ArenaAllocator allocator(global_allocator_->GetArenaPool());
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loop_allocator_ = &allocator;
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// Perform loop optimizations.
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LocalRun();
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if (top_loop_ == nullptr) {
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graph_->SetHasLoops(false); // no more loops
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}
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// Detach.
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loop_allocator_ = nullptr;
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last_loop_ = top_loop_ = nullptr;
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}
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void HLoopOptimization::LocalRun() {
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// Build the linear order using the phase-local allocator. This step enables building
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// a loop hierarchy that properly reflects the outer-inner and previous-next relation.
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ArenaVector<HBasicBlock*> linear_order(loop_allocator_->Adapter(kArenaAllocLinearOrder));
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LinearizeGraph(graph_, loop_allocator_, &linear_order);
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// Build the loop hierarchy.
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for (HBasicBlock* block : linear_order) {
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if (block->IsLoopHeader()) {
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AddLoop(block->GetLoopInformation());
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}
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}
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// Traverse the loop hierarchy inner-to-outer and optimize. Traversal can use
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// temporary data structures using the phase-local allocator. All new HIR
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// should use the global allocator.
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if (top_loop_ != nullptr) {
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ArenaSet<HInstruction*> iset(loop_allocator_->Adapter(kArenaAllocLoopOptimization));
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ArenaSet<ArrayReference> refs(loop_allocator_->Adapter(kArenaAllocLoopOptimization));
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ArenaSafeMap<HInstruction*, HInstruction*> map(
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std::less<HInstruction*>(), loop_allocator_->Adapter(kArenaAllocLoopOptimization));
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// Attach.
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iset_ = &iset;
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vector_refs_ = &refs;
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vector_map_ = ↦
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// Traverse.
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TraverseLoopsInnerToOuter(top_loop_);
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// Detach.
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iset_ = nullptr;
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vector_refs_ = nullptr;
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vector_map_ = nullptr;
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}
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}
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void HLoopOptimization::AddLoop(HLoopInformation* loop_info) {
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DCHECK(loop_info != nullptr);
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LoopNode* node = new (loop_allocator_) LoopNode(loop_info);
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if (last_loop_ == nullptr) {
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// First loop.
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DCHECK(top_loop_ == nullptr);
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last_loop_ = top_loop_ = node;
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} else if (loop_info->IsIn(*last_loop_->loop_info)) {
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// Inner loop.
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node->outer = last_loop_;
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DCHECK(last_loop_->inner == nullptr);
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last_loop_ = last_loop_->inner = node;
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} else {
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// Subsequent loop.
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while (last_loop_->outer != nullptr && !loop_info->IsIn(*last_loop_->outer->loop_info)) {
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last_loop_ = last_loop_->outer;
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}
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node->outer = last_loop_->outer;
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node->previous = last_loop_;
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DCHECK(last_loop_->next == nullptr);
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last_loop_ = last_loop_->next = node;
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}
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}
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void HLoopOptimization::RemoveLoop(LoopNode* node) {
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DCHECK(node != nullptr);
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DCHECK(node->inner == nullptr);
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if (node->previous != nullptr) {
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// Within sequence.
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node->previous->next = node->next;
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if (node->next != nullptr) {
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node->next->previous = node->previous;
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}
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} else {
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// First of sequence.
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if (node->outer != nullptr) {
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node->outer->inner = node->next;
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} else {
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top_loop_ = node->next;
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}
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if (node->next != nullptr) {
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node->next->outer = node->outer;
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node->next->previous = nullptr;
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}
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}
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}
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void HLoopOptimization::TraverseLoopsInnerToOuter(LoopNode* node) {
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for ( ; node != nullptr; node = node->next) {
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// Visit inner loops first.
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uint32_t current_induction_simplification_count = induction_simplication_count_;
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if (node->inner != nullptr) {
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TraverseLoopsInnerToOuter(node->inner);
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}
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// Recompute induction information of this loop if the induction
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// of any inner loop has been simplified.
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if (current_induction_simplification_count != induction_simplication_count_) {
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induction_range_.ReVisit(node->loop_info);
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}
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// Repeat simplifications in the loop-body until no more changes occur.
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// Note that since each simplification consists of eliminating code (without
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// introducing new code), this process is always finite.
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do {
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simplified_ = false;
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SimplifyInduction(node);
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SimplifyBlocks(node);
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} while (simplified_);
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// Optimize inner loop.
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if (node->inner == nullptr) {
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OptimizeInnerLoop(node);
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}
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}
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}
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//
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// Optimization.
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//
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void HLoopOptimization::SimplifyInduction(LoopNode* node) {
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HBasicBlock* header = node->loop_info->GetHeader();
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HBasicBlock* preheader = node->loop_info->GetPreHeader();
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// Scan the phis in the header to find opportunities to simplify an induction
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// cycle that is only used outside the loop. Replace these uses, if any, with
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// the last value and remove the induction cycle.
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// Examples: for (int i = 0; x != null; i++) { .... no i .... }
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// for (int i = 0; i < 10; i++, k++) { .... no k .... } return k;
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for (HInstructionIterator it(header->GetPhis()); !it.Done(); it.Advance()) {
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HPhi* phi = it.Current()->AsPhi();
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iset_->clear(); // prepare phi induction
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if (TrySetPhiInduction(phi, /*restrict_uses*/ true) &&
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TryAssignLastValue(node->loop_info, phi, preheader, /*collect_loop_uses*/ false)) {
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// Note that it's ok to have replaced uses after the loop with the last value, without
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// being able to remove the cycle. Environment uses (which are the reason we may not be
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// able to remove the cycle) within the loop will still hold the right value.
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if (CanRemoveCycle()) {
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for (HInstruction* i : *iset_) {
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RemoveFromCycle(i);
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}
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simplified_ = true;
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}
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}
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}
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}
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void HLoopOptimization::SimplifyBlocks(LoopNode* node) {
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// Iterate over all basic blocks in the loop-body.
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for (HBlocksInLoopIterator it(*node->loop_info); !it.Done(); it.Advance()) {
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HBasicBlock* block = it.Current();
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// Remove dead instructions from the loop-body.
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RemoveDeadInstructions(block->GetPhis());
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RemoveDeadInstructions(block->GetInstructions());
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// Remove trivial control flow blocks from the loop-body.
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if (block->GetPredecessors().size() == 1 &&
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block->GetSuccessors().size() == 1 &&
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block->GetSingleSuccessor()->GetPredecessors().size() == 1) {
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simplified_ = true;
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block->MergeWith(block->GetSingleSuccessor());
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} else if (block->GetSuccessors().size() == 2) {
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// Trivial if block can be bypassed to either branch.
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HBasicBlock* succ0 = block->GetSuccessors()[0];
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HBasicBlock* succ1 = block->GetSuccessors()[1];
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HBasicBlock* meet0 = nullptr;
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HBasicBlock* meet1 = nullptr;
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if (succ0 != succ1 &&
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IsGotoBlock(succ0, &meet0) &&
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IsGotoBlock(succ1, &meet1) &&
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meet0 == meet1 && // meets again
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meet0 != block && // no self-loop
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meet0->GetPhis().IsEmpty()) { // not used for merging
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simplified_ = true;
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succ0->DisconnectAndDelete();
|
|
if (block->Dominates(meet0)) {
|
|
block->RemoveDominatedBlock(meet0);
|
|
succ1->AddDominatedBlock(meet0);
|
|
meet0->SetDominator(succ1);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void HLoopOptimization::OptimizeInnerLoop(LoopNode* node) {
|
|
HBasicBlock* header = node->loop_info->GetHeader();
|
|
HBasicBlock* preheader = node->loop_info->GetPreHeader();
|
|
// Ensure loop header logic is finite.
|
|
int64_t trip_count = 0;
|
|
if (!induction_range_.IsFinite(node->loop_info, &trip_count)) {
|
|
return;
|
|
}
|
|
|
|
// Ensure there is only a single loop-body (besides the header).
|
|
HBasicBlock* body = nullptr;
|
|
for (HBlocksInLoopIterator it(*node->loop_info); !it.Done(); it.Advance()) {
|
|
if (it.Current() != header) {
|
|
if (body != nullptr) {
|
|
return;
|
|
}
|
|
body = it.Current();
|
|
}
|
|
}
|
|
CHECK(body != nullptr);
|
|
// Ensure there is only a single exit point.
|
|
if (header->GetSuccessors().size() != 2) {
|
|
return;
|
|
}
|
|
HBasicBlock* exit = (header->GetSuccessors()[0] == body)
|
|
? header->GetSuccessors()[1]
|
|
: header->GetSuccessors()[0];
|
|
// Ensure exit can only be reached by exiting loop.
|
|
if (exit->GetPredecessors().size() != 1) {
|
|
return;
|
|
}
|
|
// Detect either an empty loop (no side effects other than plain iteration) or
|
|
// a trivial loop (just iterating once). Replace subsequent index uses, if any,
|
|
// with the last value and remove the loop, possibly after unrolling its body.
|
|
HInstruction* phi = header->GetFirstPhi();
|
|
iset_->clear(); // prepare phi induction
|
|
if (TrySetSimpleLoopHeader(header)) {
|
|
bool is_empty = IsEmptyBody(body);
|
|
if ((is_empty || trip_count == 1) &&
|
|
TryAssignLastValue(node->loop_info, phi, preheader, /*collect_loop_uses*/ true)) {
|
|
if (!is_empty) {
|
|
// Unroll the loop-body, which sees initial value of the index.
|
|
phi->ReplaceWith(phi->InputAt(0));
|
|
preheader->MergeInstructionsWith(body);
|
|
}
|
|
body->DisconnectAndDelete();
|
|
exit->RemovePredecessor(header);
|
|
header->RemoveSuccessor(exit);
|
|
header->RemoveDominatedBlock(exit);
|
|
header->DisconnectAndDelete();
|
|
preheader->AddSuccessor(exit);
|
|
preheader->AddInstruction(new (global_allocator_) HGoto());
|
|
preheader->AddDominatedBlock(exit);
|
|
exit->SetDominator(preheader);
|
|
RemoveLoop(node); // update hierarchy
|
|
return;
|
|
}
|
|
}
|
|
|
|
// Vectorize loop, if possible and valid.
|
|
if (kEnableVectorization) {
|
|
iset_->clear(); // prepare phi induction
|
|
if (TrySetSimpleLoopHeader(header) &&
|
|
ShouldVectorize(node, body, trip_count) &&
|
|
TryAssignLastValue(node->loop_info, phi, preheader, /*collect_loop_uses*/ true)) {
|
|
Vectorize(node, body, exit, trip_count);
|
|
graph_->SetHasSIMD(true); // flag SIMD usage
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
//
|
|
// Loop vectorization. The implementation is based on the book by Aart J.C. Bik:
|
|
// "The Software Vectorization Handbook. Applying Multimedia Extensions for Maximum Performance."
|
|
// Intel Press, June, 2004 (http://www.aartbik.com/).
|
|
//
|
|
|
|
bool HLoopOptimization::ShouldVectorize(LoopNode* node, HBasicBlock* block, int64_t trip_count) {
|
|
// Reset vector bookkeeping.
|
|
vector_length_ = 0;
|
|
vector_refs_->clear();
|
|
vector_peeling_candidate_ = nullptr;
|
|
vector_runtime_test_a_ =
|
|
vector_runtime_test_b_= nullptr;
|
|
|
|
// Phis in the loop-body prevent vectorization.
|
|
if (!block->GetPhis().IsEmpty()) {
|
|
return false;
|
|
}
|
|
|
|
// Scan the loop-body, starting a right-hand-side tree traversal at each left-hand-side
|
|
// occurrence, which allows passing down attributes down the use tree.
|
|
for (HInstructionIterator it(block->GetInstructions()); !it.Done(); it.Advance()) {
|
|
if (!VectorizeDef(node, it.Current(), /*generate_code*/ false)) {
|
|
return false; // failure to vectorize a left-hand-side
|
|
}
|
|
}
|
|
|
|
// Does vectorization seem profitable?
|
|
if (!IsVectorizationProfitable(trip_count)) {
|
|
return false;
|
|
}
|
|
|
|
// Data dependence analysis. Find each pair of references with same type, where
|
|
// at least one is a write. Each such pair denotes a possible data dependence.
|
|
// This analysis exploits the property that differently typed arrays cannot be
|
|
// aliased, as well as the property that references either point to the same
|
|
// array or to two completely disjoint arrays, i.e., no partial aliasing.
|
|
// Other than a few simply heuristics, no detailed subscript analysis is done.
|
|
for (auto i = vector_refs_->begin(); i != vector_refs_->end(); ++i) {
|
|
for (auto j = i; ++j != vector_refs_->end(); ) {
|
|
if (i->type == j->type && (i->lhs || j->lhs)) {
|
|
// Found same-typed a[i+x] vs. b[i+y], where at least one is a write.
|
|
HInstruction* a = i->base;
|
|
HInstruction* b = j->base;
|
|
HInstruction* x = i->offset;
|
|
HInstruction* y = j->offset;
|
|
if (a == b) {
|
|
// Found a[i+x] vs. a[i+y]. Accept if x == y (loop-independent data dependence).
|
|
// Conservatively assume a loop-carried data dependence otherwise, and reject.
|
|
if (x != y) {
|
|
return false;
|
|
}
|
|
} else {
|
|
// Found a[i+x] vs. b[i+y]. Accept if x == y (at worst loop-independent data dependence).
|
|
// Conservatively assume a potential loop-carried data dependence otherwise, avoided by
|
|
// generating an explicit a != b disambiguation runtime test on the two references.
|
|
if (x != y) {
|
|
// To avoid excessive overhead, we only accept one a != b test.
|
|
if (vector_runtime_test_a_ == nullptr) {
|
|
// First test found.
|
|
vector_runtime_test_a_ = a;
|
|
vector_runtime_test_b_ = b;
|
|
} else if ((vector_runtime_test_a_ != a || vector_runtime_test_b_ != b) &&
|
|
(vector_runtime_test_a_ != b || vector_runtime_test_b_ != a)) {
|
|
return false; // second test would be needed
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// Consider dynamic loop peeling for alignment.
|
|
SetPeelingCandidate(trip_count);
|
|
|
|
// Success!
|
|
return true;
|
|
}
|
|
|
|
void HLoopOptimization::Vectorize(LoopNode* node,
|
|
HBasicBlock* block,
|
|
HBasicBlock* exit,
|
|
int64_t trip_count) {
|
|
Primitive::Type induc_type = Primitive::kPrimInt;
|
|
HBasicBlock* header = node->loop_info->GetHeader();
|
|
HBasicBlock* preheader = node->loop_info->GetPreHeader();
|
|
|
|
// Pick a loop unrolling factor for the vector loop.
|
|
uint32_t unroll = GetUnrollingFactor(block, trip_count);
|
|
uint32_t chunk = vector_length_ * unroll;
|
|
|
|
// A cleanup loop is needed, at least, for any unknown trip count or
|
|
// for a known trip count with remainder iterations after vectorization.
|
|
bool needs_cleanup = trip_count == 0 || (trip_count % chunk) != 0;
|
|
|
|
// Adjust vector bookkeeping.
|
|
iset_->clear(); // prepare phi induction
|
|
bool is_simple_loop_header = TrySetSimpleLoopHeader(header); // fills iset_
|
|
DCHECK(is_simple_loop_header);
|
|
vector_header_ = header;
|
|
vector_body_ = block;
|
|
|
|
// Generate dynamic loop peeling trip count, if needed:
|
|
// ptc = <peeling-needed-for-candidate>
|
|
HInstruction* ptc = nullptr;
|
|
if (vector_peeling_candidate_ != nullptr) {
|
|
DCHECK_LT(vector_length_, trip_count) << "dynamic peeling currently requires known trip count";
|
|
//
|
|
// TODO: Implement this. Compute address of first access memory location and
|
|
// compute peeling factor to obtain kAlignedBase alignment.
|
|
//
|
|
needs_cleanup = true;
|
|
}
|
|
|
|
// Generate loop control:
|
|
// stc = <trip-count>;
|
|
// vtc = stc - (stc - ptc) % chunk;
|
|
// i = 0;
|
|
HInstruction* stc = induction_range_.GenerateTripCount(node->loop_info, graph_, preheader);
|
|
HInstruction* vtc = stc;
|
|
if (needs_cleanup) {
|
|
DCHECK(IsPowerOfTwo(chunk));
|
|
HInstruction* diff = stc;
|
|
if (ptc != nullptr) {
|
|
diff = Insert(preheader, new (global_allocator_) HSub(induc_type, stc, ptc));
|
|
}
|
|
HInstruction* rem = Insert(
|
|
preheader, new (global_allocator_) HAnd(induc_type,
|
|
diff,
|
|
graph_->GetIntConstant(chunk - 1)));
|
|
vtc = Insert(preheader, new (global_allocator_) HSub(induc_type, stc, rem));
|
|
}
|
|
vector_index_ = graph_->GetIntConstant(0);
|
|
|
|
// Generate runtime disambiguation test:
|
|
// vtc = a != b ? vtc : 0;
|
|
if (vector_runtime_test_a_ != nullptr) {
|
|
HInstruction* rt = Insert(
|
|
preheader,
|
|
new (global_allocator_) HNotEqual(vector_runtime_test_a_, vector_runtime_test_b_));
|
|
vtc = Insert(preheader,
|
|
new (global_allocator_) HSelect(rt, vtc, graph_->GetIntConstant(0), kNoDexPc));
|
|
needs_cleanup = true;
|
|
}
|
|
|
|
// Generate dynamic peeling loop for alignment, if needed:
|
|
// for ( ; i < ptc; i += 1)
|
|
// <loop-body>
|
|
if (ptc != nullptr) {
|
|
vector_mode_ = kSequential;
|
|
GenerateNewLoop(node,
|
|
block,
|
|
graph_->TransformLoopForVectorization(vector_header_, vector_body_, exit),
|
|
vector_index_,
|
|
ptc,
|
|
graph_->GetIntConstant(1),
|
|
/*unroll*/ 1);
|
|
}
|
|
|
|
// Generate vector loop, possibly further unrolled:
|
|
// for ( ; i < vtc; i += chunk)
|
|
// <vectorized-loop-body>
|
|
vector_mode_ = kVector;
|
|
GenerateNewLoop(node,
|
|
block,
|
|
graph_->TransformLoopForVectorization(vector_header_, vector_body_, exit),
|
|
vector_index_,
|
|
vtc,
|
|
graph_->GetIntConstant(vector_length_), // increment per unroll
|
|
unroll);
|
|
HLoopInformation* vloop = vector_header_->GetLoopInformation();
|
|
|
|
// Generate cleanup loop, if needed:
|
|
// for ( ; i < stc; i += 1)
|
|
// <loop-body>
|
|
if (needs_cleanup) {
|
|
vector_mode_ = kSequential;
|
|
GenerateNewLoop(node,
|
|
block,
|
|
graph_->TransformLoopForVectorization(vector_header_, vector_body_, exit),
|
|
vector_index_,
|
|
stc,
|
|
graph_->GetIntConstant(1),
|
|
/*unroll*/ 1);
|
|
}
|
|
|
|
// Remove the original loop by disconnecting the body block
|
|
// and removing all instructions from the header.
|
|
block->DisconnectAndDelete();
|
|
while (!header->GetFirstInstruction()->IsGoto()) {
|
|
header->RemoveInstruction(header->GetFirstInstruction());
|
|
}
|
|
// Update loop hierarchy: the old header now resides in the same outer loop
|
|
// as the old preheader. Note that we don't bother putting sequential
|
|
// loops back in the hierarchy at this point.
|
|
header->SetLoopInformation(preheader->GetLoopInformation()); // outward
|
|
node->loop_info = vloop;
|
|
}
|
|
|
|
void HLoopOptimization::GenerateNewLoop(LoopNode* node,
|
|
HBasicBlock* block,
|
|
HBasicBlock* new_preheader,
|
|
HInstruction* lo,
|
|
HInstruction* hi,
|
|
HInstruction* step,
|
|
uint32_t unroll) {
|
|
DCHECK(unroll == 1 || vector_mode_ == kVector);
|
|
Primitive::Type induc_type = Primitive::kPrimInt;
|
|
// Prepare new loop.
|
|
vector_preheader_ = new_preheader,
|
|
vector_header_ = vector_preheader_->GetSingleSuccessor();
|
|
vector_body_ = vector_header_->GetSuccessors()[1];
|
|
HPhi* phi = new (global_allocator_) HPhi(global_allocator_,
|
|
kNoRegNumber,
|
|
0,
|
|
HPhi::ToPhiType(induc_type));
|
|
// Generate header and prepare body.
|
|
// for (i = lo; i < hi; i += step)
|
|
// <loop-body>
|
|
HInstruction* cond = new (global_allocator_) HAboveOrEqual(phi, hi);
|
|
vector_header_->AddPhi(phi);
|
|
vector_header_->AddInstruction(cond);
|
|
vector_header_->AddInstruction(new (global_allocator_) HIf(cond));
|
|
vector_index_ = phi;
|
|
for (uint32_t u = 0; u < unroll; u++) {
|
|
// Clear map, leaving loop invariants setup during unrolling.
|
|
if (u == 0) {
|
|
vector_map_->clear();
|
|
} else {
|
|
for (auto i = vector_map_->begin(); i != vector_map_->end(); ) {
|
|
if (i->second->IsVecReplicateScalar()) {
|
|
DCHECK(node->loop_info->IsDefinedOutOfTheLoop(i->first));
|
|
++i;
|
|
} else {
|
|
i = vector_map_->erase(i);
|
|
}
|
|
}
|
|
}
|
|
// Generate instruction map.
|
|
for (HInstructionIterator it(block->GetInstructions()); !it.Done(); it.Advance()) {
|
|
bool vectorized_def = VectorizeDef(node, it.Current(), /*generate_code*/ true);
|
|
DCHECK(vectorized_def);
|
|
}
|
|
// Generate body from the instruction map, but in original program order.
|
|
HEnvironment* env = vector_header_->GetFirstInstruction()->GetEnvironment();
|
|
for (HInstructionIterator it(block->GetInstructions()); !it.Done(); it.Advance()) {
|
|
auto i = vector_map_->find(it.Current());
|
|
if (i != vector_map_->end() && !i->second->IsInBlock()) {
|
|
Insert(vector_body_, i->second);
|
|
// Deal with instructions that need an environment, such as the scalar intrinsics.
|
|
if (i->second->NeedsEnvironment()) {
|
|
i->second->CopyEnvironmentFromWithLoopPhiAdjustment(env, vector_header_);
|
|
}
|
|
}
|
|
}
|
|
vector_index_ = new (global_allocator_) HAdd(induc_type, vector_index_, step);
|
|
Insert(vector_body_, vector_index_);
|
|
}
|
|
// Finalize phi for the loop index.
|
|
phi->AddInput(lo);
|
|
phi->AddInput(vector_index_);
|
|
vector_index_ = phi;
|
|
}
|
|
|
|
// TODO: accept reductions at left-hand-side, mixed-type store idioms, etc.
|
|
bool HLoopOptimization::VectorizeDef(LoopNode* node,
|
|
HInstruction* instruction,
|
|
bool generate_code) {
|
|
// Accept a left-hand-side array base[index] for
|
|
// (1) supported vector type,
|
|
// (2) loop-invariant base,
|
|
// (3) unit stride index,
|
|
// (4) vectorizable right-hand-side value.
|
|
uint64_t restrictions = kNone;
|
|
if (instruction->IsArraySet()) {
|
|
Primitive::Type type = instruction->AsArraySet()->GetComponentType();
|
|
HInstruction* base = instruction->InputAt(0);
|
|
HInstruction* index = instruction->InputAt(1);
|
|
HInstruction* value = instruction->InputAt(2);
|
|
HInstruction* offset = nullptr;
|
|
if (TrySetVectorType(type, &restrictions) &&
|
|
node->loop_info->IsDefinedOutOfTheLoop(base) &&
|
|
induction_range_.IsUnitStride(instruction, index, graph_, &offset) &&
|
|
VectorizeUse(node, value, generate_code, type, restrictions)) {
|
|
if (generate_code) {
|
|
GenerateVecSub(index, offset);
|
|
GenerateVecMem(instruction, vector_map_->Get(index), vector_map_->Get(value), offset, type);
|
|
} else {
|
|
vector_refs_->insert(ArrayReference(base, offset, type, /*lhs*/ true));
|
|
}
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
// Branch back okay.
|
|
if (instruction->IsGoto()) {
|
|
return true;
|
|
}
|
|
// Otherwise accept only expressions with no effects outside the immediate loop-body.
|
|
// Note that actual uses are inspected during right-hand-side tree traversal.
|
|
return !IsUsedOutsideLoop(node->loop_info, instruction) && !instruction->DoesAnyWrite();
|
|
}
|
|
|
|
// TODO: saturation arithmetic.
|
|
bool HLoopOptimization::VectorizeUse(LoopNode* node,
|
|
HInstruction* instruction,
|
|
bool generate_code,
|
|
Primitive::Type type,
|
|
uint64_t restrictions) {
|
|
// Accept anything for which code has already been generated.
|
|
if (generate_code) {
|
|
if (vector_map_->find(instruction) != vector_map_->end()) {
|
|
return true;
|
|
}
|
|
}
|
|
// Continue the right-hand-side tree traversal, passing in proper
|
|
// types and vector restrictions along the way. During code generation,
|
|
// all new nodes are drawn from the global allocator.
|
|
if (node->loop_info->IsDefinedOutOfTheLoop(instruction)) {
|
|
// Accept invariant use, using scalar expansion.
|
|
if (generate_code) {
|
|
GenerateVecInv(instruction, type);
|
|
}
|
|
return true;
|
|
} else if (instruction->IsArrayGet()) {
|
|
// Deal with vector restrictions.
|
|
if (instruction->AsArrayGet()->IsStringCharAt() &&
|
|
HasVectorRestrictions(restrictions, kNoStringCharAt)) {
|
|
return false;
|
|
}
|
|
// Accept a right-hand-side array base[index] for
|
|
// (1) exact matching vector type,
|
|
// (2) loop-invariant base,
|
|
// (3) unit stride index,
|
|
// (4) vectorizable right-hand-side value.
|
|
HInstruction* base = instruction->InputAt(0);
|
|
HInstruction* index = instruction->InputAt(1);
|
|
HInstruction* offset = nullptr;
|
|
if (type == instruction->GetType() &&
|
|
node->loop_info->IsDefinedOutOfTheLoop(base) &&
|
|
induction_range_.IsUnitStride(instruction, index, graph_, &offset)) {
|
|
if (generate_code) {
|
|
GenerateVecSub(index, offset);
|
|
GenerateVecMem(instruction, vector_map_->Get(index), nullptr, offset, type);
|
|
} else {
|
|
vector_refs_->insert(ArrayReference(base, offset, type, /*lhs*/ false));
|
|
}
|
|
return true;
|
|
}
|
|
} else if (instruction->IsTypeConversion()) {
|
|
// Accept particular type conversions.
|
|
HTypeConversion* conversion = instruction->AsTypeConversion();
|
|
HInstruction* opa = conversion->InputAt(0);
|
|
Primitive::Type from = conversion->GetInputType();
|
|
Primitive::Type to = conversion->GetResultType();
|
|
if ((to == Primitive::kPrimByte ||
|
|
to == Primitive::kPrimChar ||
|
|
to == Primitive::kPrimShort) && from == Primitive::kPrimInt) {
|
|
// Accept a "narrowing" type conversion from a "wider" computation for
|
|
// (1) conversion into final required type,
|
|
// (2) vectorizable operand,
|
|
// (3) "wider" operations cannot bring in higher order bits.
|
|
if (to == type && VectorizeUse(node, opa, generate_code, type, restrictions | kNoHiBits)) {
|
|
if (generate_code) {
|
|
if (vector_mode_ == kVector) {
|
|
vector_map_->Put(instruction, vector_map_->Get(opa)); // operand pass-through
|
|
} else {
|
|
GenerateVecOp(instruction, vector_map_->Get(opa), nullptr, type);
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
} else if (to == Primitive::kPrimFloat && from == Primitive::kPrimInt) {
|
|
DCHECK_EQ(to, type);
|
|
// Accept int to float conversion for
|
|
// (1) supported int,
|
|
// (2) vectorizable operand.
|
|
if (TrySetVectorType(from, &restrictions) &&
|
|
VectorizeUse(node, opa, generate_code, from, restrictions)) {
|
|
if (generate_code) {
|
|
GenerateVecOp(instruction, vector_map_->Get(opa), nullptr, type);
|
|
}
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
} else if (instruction->IsNeg() || instruction->IsNot() || instruction->IsBooleanNot()) {
|
|
// Accept unary operator for vectorizable operand.
|
|
HInstruction* opa = instruction->InputAt(0);
|
|
if (VectorizeUse(node, opa, generate_code, type, restrictions)) {
|
|
if (generate_code) {
|
|
GenerateVecOp(instruction, vector_map_->Get(opa), nullptr, type);
|
|
}
|
|
return true;
|
|
}
|
|
} else if (instruction->IsAdd() || instruction->IsSub() ||
|
|
instruction->IsMul() || instruction->IsDiv() ||
|
|
instruction->IsAnd() || instruction->IsOr() || instruction->IsXor()) {
|
|
// Deal with vector restrictions.
|
|
if ((instruction->IsMul() && HasVectorRestrictions(restrictions, kNoMul)) ||
|
|
(instruction->IsDiv() && HasVectorRestrictions(restrictions, kNoDiv))) {
|
|
return false;
|
|
}
|
|
// Accept binary operator for vectorizable operands.
|
|
HInstruction* opa = instruction->InputAt(0);
|
|
HInstruction* opb = instruction->InputAt(1);
|
|
if (VectorizeUse(node, opa, generate_code, type, restrictions) &&
|
|
VectorizeUse(node, opb, generate_code, type, restrictions)) {
|
|
if (generate_code) {
|
|
GenerateVecOp(instruction, vector_map_->Get(opa), vector_map_->Get(opb), type);
|
|
}
|
|
return true;
|
|
}
|
|
} else if (instruction->IsShl() || instruction->IsShr() || instruction->IsUShr()) {
|
|
// Recognize vectorization idioms.
|
|
if (VectorizeHalvingAddIdiom(node, instruction, generate_code, type, restrictions)) {
|
|
return true;
|
|
}
|
|
// Deal with vector restrictions.
|
|
HInstruction* opa = instruction->InputAt(0);
|
|
HInstruction* opb = instruction->InputAt(1);
|
|
HInstruction* r = opa;
|
|
bool is_unsigned = false;
|
|
if ((HasVectorRestrictions(restrictions, kNoShift)) ||
|
|
(instruction->IsShr() && HasVectorRestrictions(restrictions, kNoShr))) {
|
|
return false; // unsupported instruction
|
|
} else if (HasVectorRestrictions(restrictions, kNoHiBits)) {
|
|
// Shifts right need extra care to account for higher order bits.
|
|
// TODO: less likely shr/unsigned and ushr/signed can by flipping signess.
|
|
if (instruction->IsShr() &&
|
|
(!IsNarrowerOperand(opa, type, &r, &is_unsigned) || is_unsigned)) {
|
|
return false; // reject, unless all operands are sign-extension narrower
|
|
} else if (instruction->IsUShr() &&
|
|
(!IsNarrowerOperand(opa, type, &r, &is_unsigned) || !is_unsigned)) {
|
|
return false; // reject, unless all operands are zero-extension narrower
|
|
}
|
|
}
|
|
// Accept shift operator for vectorizable/invariant operands.
|
|
// TODO: accept symbolic, albeit loop invariant shift factors.
|
|
DCHECK(r != nullptr);
|
|
if (generate_code && vector_mode_ != kVector) { // de-idiom
|
|
r = opa;
|
|
}
|
|
int64_t distance = 0;
|
|
if (VectorizeUse(node, r, generate_code, type, restrictions) &&
|
|
IsInt64AndGet(opb, /*out*/ &distance)) {
|
|
// Restrict shift distance to packed data type width.
|
|
int64_t max_distance = Primitive::ComponentSize(type) * 8;
|
|
if (0 <= distance && distance < max_distance) {
|
|
if (generate_code) {
|
|
GenerateVecOp(instruction, vector_map_->Get(r), opb, type);
|
|
}
|
|
return true;
|
|
}
|
|
}
|
|
} else if (instruction->IsInvokeStaticOrDirect()) {
|
|
// Accept particular intrinsics.
|
|
HInvokeStaticOrDirect* invoke = instruction->AsInvokeStaticOrDirect();
|
|
switch (invoke->GetIntrinsic()) {
|
|
case Intrinsics::kMathAbsInt:
|
|
case Intrinsics::kMathAbsLong:
|
|
case Intrinsics::kMathAbsFloat:
|
|
case Intrinsics::kMathAbsDouble: {
|
|
// Deal with vector restrictions.
|
|
HInstruction* opa = instruction->InputAt(0);
|
|
HInstruction* r = opa;
|
|
bool is_unsigned = false;
|
|
if (HasVectorRestrictions(restrictions, kNoAbs)) {
|
|
return false;
|
|
} else if (HasVectorRestrictions(restrictions, kNoHiBits) &&
|
|
(!IsNarrowerOperand(opa, type, &r, &is_unsigned) || is_unsigned)) {
|
|
return false; // reject, unless operand is sign-extension narrower
|
|
}
|
|
// Accept ABS(x) for vectorizable operand.
|
|
DCHECK(r != nullptr);
|
|
if (generate_code && vector_mode_ != kVector) { // de-idiom
|
|
r = opa;
|
|
}
|
|
if (VectorizeUse(node, r, generate_code, type, restrictions)) {
|
|
if (generate_code) {
|
|
GenerateVecOp(instruction, vector_map_->Get(r), nullptr, type);
|
|
}
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
case Intrinsics::kMathMinIntInt:
|
|
case Intrinsics::kMathMinLongLong:
|
|
case Intrinsics::kMathMinFloatFloat:
|
|
case Intrinsics::kMathMinDoubleDouble:
|
|
case Intrinsics::kMathMaxIntInt:
|
|
case Intrinsics::kMathMaxLongLong:
|
|
case Intrinsics::kMathMaxFloatFloat:
|
|
case Intrinsics::kMathMaxDoubleDouble: {
|
|
// Deal with vector restrictions.
|
|
HInstruction* opa = instruction->InputAt(0);
|
|
HInstruction* opb = instruction->InputAt(1);
|
|
HInstruction* r = opa;
|
|
HInstruction* s = opb;
|
|
bool is_unsigned = false;
|
|
if (HasVectorRestrictions(restrictions, kNoMinMax)) {
|
|
return false;
|
|
} else if (HasVectorRestrictions(restrictions, kNoHiBits) &&
|
|
!IsNarrowerOperands(opa, opb, type, &r, &s, &is_unsigned)) {
|
|
return false; // reject, unless all operands are same-extension narrower
|
|
}
|
|
// Accept MIN/MAX(x, y) for vectorizable operands.
|
|
DCHECK(r != nullptr && s != nullptr);
|
|
if (generate_code && vector_mode_ != kVector) { // de-idiom
|
|
r = opa;
|
|
s = opb;
|
|
}
|
|
if (VectorizeUse(node, r, generate_code, type, restrictions) &&
|
|
VectorizeUse(node, s, generate_code, type, restrictions)) {
|
|
if (generate_code) {
|
|
GenerateVecOp(
|
|
instruction, vector_map_->Get(r), vector_map_->Get(s), type, is_unsigned);
|
|
}
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
default:
|
|
return false;
|
|
} // switch
|
|
}
|
|
return false;
|
|
}
|
|
|
|
bool HLoopOptimization::TrySetVectorType(Primitive::Type type, uint64_t* restrictions) {
|
|
const InstructionSetFeatures* features = compiler_driver_->GetInstructionSetFeatures();
|
|
switch (compiler_driver_->GetInstructionSet()) {
|
|
case kArm:
|
|
case kThumb2:
|
|
// Allow vectorization for all ARM devices, because Android assumes that
|
|
// ARM 32-bit always supports advanced SIMD.
|
|
switch (type) {
|
|
case Primitive::kPrimBoolean:
|
|
case Primitive::kPrimByte:
|
|
*restrictions |= kNoDiv;
|
|
return TrySetVectorLength(8);
|
|
case Primitive::kPrimChar:
|
|
case Primitive::kPrimShort:
|
|
*restrictions |= kNoDiv | kNoStringCharAt;
|
|
return TrySetVectorLength(4);
|
|
case Primitive::kPrimInt:
|
|
*restrictions |= kNoDiv;
|
|
return TrySetVectorLength(2);
|
|
default:
|
|
break;
|
|
}
|
|
return false;
|
|
case kArm64:
|
|
// Allow vectorization for all ARM devices, because Android assumes that
|
|
// ARMv8 AArch64 always supports advanced SIMD.
|
|
switch (type) {
|
|
case Primitive::kPrimBoolean:
|
|
case Primitive::kPrimByte:
|
|
*restrictions |= kNoDiv;
|
|
return TrySetVectorLength(16);
|
|
case Primitive::kPrimChar:
|
|
case Primitive::kPrimShort:
|
|
*restrictions |= kNoDiv;
|
|
return TrySetVectorLength(8);
|
|
case Primitive::kPrimInt:
|
|
*restrictions |= kNoDiv;
|
|
return TrySetVectorLength(4);
|
|
case Primitive::kPrimLong:
|
|
*restrictions |= kNoDiv | kNoMul | kNoMinMax;
|
|
return TrySetVectorLength(2);
|
|
case Primitive::kPrimFloat:
|
|
return TrySetVectorLength(4);
|
|
case Primitive::kPrimDouble:
|
|
return TrySetVectorLength(2);
|
|
default:
|
|
return false;
|
|
}
|
|
case kX86:
|
|
case kX86_64:
|
|
// Allow vectorization for SSE4-enabled X86 devices only (128-bit vectors).
|
|
if (features->AsX86InstructionSetFeatures()->HasSSE4_1()) {
|
|
switch (type) {
|
|
case Primitive::kPrimBoolean:
|
|
case Primitive::kPrimByte:
|
|
*restrictions |= kNoMul | kNoDiv | kNoShift | kNoAbs | kNoSignedHAdd | kNoUnroundedHAdd;
|
|
return TrySetVectorLength(16);
|
|
case Primitive::kPrimChar:
|
|
case Primitive::kPrimShort:
|
|
*restrictions |= kNoDiv | kNoAbs | kNoSignedHAdd | kNoUnroundedHAdd;
|
|
return TrySetVectorLength(8);
|
|
case Primitive::kPrimInt:
|
|
*restrictions |= kNoDiv;
|
|
return TrySetVectorLength(4);
|
|
case Primitive::kPrimLong:
|
|
*restrictions |= kNoMul | kNoDiv | kNoShr | kNoAbs | kNoMinMax;
|
|
return TrySetVectorLength(2);
|
|
case Primitive::kPrimFloat:
|
|
*restrictions |= kNoMinMax; // -0.0 vs +0.0
|
|
return TrySetVectorLength(4);
|
|
case Primitive::kPrimDouble:
|
|
*restrictions |= kNoMinMax; // -0.0 vs +0.0
|
|
return TrySetVectorLength(2);
|
|
default:
|
|
break;
|
|
} // switch type
|
|
}
|
|
return false;
|
|
case kMips:
|
|
if (features->AsMipsInstructionSetFeatures()->HasMsa()) {
|
|
switch (type) {
|
|
case Primitive::kPrimBoolean:
|
|
case Primitive::kPrimByte:
|
|
*restrictions |= kNoDiv;
|
|
return TrySetVectorLength(16);
|
|
case Primitive::kPrimChar:
|
|
case Primitive::kPrimShort:
|
|
*restrictions |= kNoDiv | kNoStringCharAt;
|
|
return TrySetVectorLength(8);
|
|
case Primitive::kPrimInt:
|
|
*restrictions |= kNoDiv;
|
|
return TrySetVectorLength(4);
|
|
case Primitive::kPrimLong:
|
|
*restrictions |= kNoDiv;
|
|
return TrySetVectorLength(2);
|
|
case Primitive::kPrimFloat:
|
|
*restrictions |= kNoMinMax; // min/max(x, NaN)
|
|
return TrySetVectorLength(4);
|
|
case Primitive::kPrimDouble:
|
|
*restrictions |= kNoMinMax; // min/max(x, NaN)
|
|
return TrySetVectorLength(2);
|
|
default:
|
|
break;
|
|
} // switch type
|
|
}
|
|
return false;
|
|
case kMips64:
|
|
if (features->AsMips64InstructionSetFeatures()->HasMsa()) {
|
|
switch (type) {
|
|
case Primitive::kPrimBoolean:
|
|
case Primitive::kPrimByte:
|
|
*restrictions |= kNoDiv;
|
|
return TrySetVectorLength(16);
|
|
case Primitive::kPrimChar:
|
|
case Primitive::kPrimShort:
|
|
*restrictions |= kNoDiv | kNoStringCharAt;
|
|
return TrySetVectorLength(8);
|
|
case Primitive::kPrimInt:
|
|
*restrictions |= kNoDiv;
|
|
return TrySetVectorLength(4);
|
|
case Primitive::kPrimLong:
|
|
*restrictions |= kNoDiv;
|
|
return TrySetVectorLength(2);
|
|
case Primitive::kPrimFloat:
|
|
*restrictions |= kNoMinMax; // min/max(x, NaN)
|
|
return TrySetVectorLength(4);
|
|
case Primitive::kPrimDouble:
|
|
*restrictions |= kNoMinMax; // min/max(x, NaN)
|
|
return TrySetVectorLength(2);
|
|
default:
|
|
break;
|
|
} // switch type
|
|
}
|
|
return false;
|
|
default:
|
|
return false;
|
|
} // switch instruction set
|
|
}
|
|
|
|
bool HLoopOptimization::TrySetVectorLength(uint32_t length) {
|
|
DCHECK(IsPowerOfTwo(length) && length >= 2u);
|
|
// First time set?
|
|
if (vector_length_ == 0) {
|
|
vector_length_ = length;
|
|
}
|
|
// Different types are acceptable within a loop-body, as long as all the corresponding vector
|
|
// lengths match exactly to obtain a uniform traversal through the vector iteration space
|
|
// (idiomatic exceptions to this rule can be handled by further unrolling sub-expressions).
|
|
return vector_length_ == length;
|
|
}
|
|
|
|
void HLoopOptimization::GenerateVecInv(HInstruction* org, Primitive::Type type) {
|
|
if (vector_map_->find(org) == vector_map_->end()) {
|
|
// In scalar code, just use a self pass-through for scalar invariants
|
|
// (viz. expression remains itself).
|
|
if (vector_mode_ == kSequential) {
|
|
vector_map_->Put(org, org);
|
|
return;
|
|
}
|
|
// In vector code, explicit scalar expansion is needed.
|
|
HInstruction* vector = new (global_allocator_) HVecReplicateScalar(
|
|
global_allocator_, org, type, vector_length_);
|
|
vector_map_->Put(org, Insert(vector_preheader_, vector));
|
|
}
|
|
}
|
|
|
|
void HLoopOptimization::GenerateVecSub(HInstruction* org, HInstruction* offset) {
|
|
if (vector_map_->find(org) == vector_map_->end()) {
|
|
HInstruction* subscript = vector_index_;
|
|
int64_t value = 0;
|
|
if (!IsInt64AndGet(offset, &value) || value != 0) {
|
|
subscript = new (global_allocator_) HAdd(Primitive::kPrimInt, subscript, offset);
|
|
if (org->IsPhi()) {
|
|
Insert(vector_body_, subscript); // lacks layout placeholder
|
|
}
|
|
}
|
|
vector_map_->Put(org, subscript);
|
|
}
|
|
}
|
|
|
|
void HLoopOptimization::GenerateVecMem(HInstruction* org,
|
|
HInstruction* opa,
|
|
HInstruction* opb,
|
|
HInstruction* offset,
|
|
Primitive::Type type) {
|
|
HInstruction* vector = nullptr;
|
|
if (vector_mode_ == kVector) {
|
|
// Vector store or load.
|
|
HInstruction* base = org->InputAt(0);
|
|
if (opb != nullptr) {
|
|
vector = new (global_allocator_) HVecStore(
|
|
global_allocator_, base, opa, opb, type, vector_length_);
|
|
} else {
|
|
bool is_string_char_at = org->AsArrayGet()->IsStringCharAt();
|
|
vector = new (global_allocator_) HVecLoad(
|
|
global_allocator_, base, opa, type, vector_length_, is_string_char_at);
|
|
}
|
|
// Known dynamically enforced alignment?
|
|
// TODO: detect offset + constant differences.
|
|
// TODO: long run, static alignment analysis?
|
|
if (vector_peeling_candidate_ != nullptr &&
|
|
vector_peeling_candidate_->base == base &&
|
|
vector_peeling_candidate_->offset == offset) {
|
|
vector->AsVecMemoryOperation()->SetAlignment(Alignment(kAlignedBase, 0));
|
|
}
|
|
} else {
|
|
// Scalar store or load.
|
|
DCHECK(vector_mode_ == kSequential);
|
|
if (opb != nullptr) {
|
|
vector = new (global_allocator_) HArraySet(org->InputAt(0), opa, opb, type, kNoDexPc);
|
|
} else {
|
|
bool is_string_char_at = org->AsArrayGet()->IsStringCharAt();
|
|
vector = new (global_allocator_) HArrayGet(
|
|
org->InputAt(0), opa, type, kNoDexPc, is_string_char_at);
|
|
}
|
|
}
|
|
vector_map_->Put(org, vector);
|
|
}
|
|
|
|
#define GENERATE_VEC(x, y) \
|
|
if (vector_mode_ == kVector) { \
|
|
vector = (x); \
|
|
} else { \
|
|
DCHECK(vector_mode_ == kSequential); \
|
|
vector = (y); \
|
|
} \
|
|
break;
|
|
|
|
void HLoopOptimization::GenerateVecOp(HInstruction* org,
|
|
HInstruction* opa,
|
|
HInstruction* opb,
|
|
Primitive::Type type,
|
|
bool is_unsigned) {
|
|
if (vector_mode_ == kSequential) {
|
|
// Non-converting scalar code follows implicit integral promotion.
|
|
if (!org->IsTypeConversion() && (type == Primitive::kPrimBoolean ||
|
|
type == Primitive::kPrimByte ||
|
|
type == Primitive::kPrimChar ||
|
|
type == Primitive::kPrimShort)) {
|
|
type = Primitive::kPrimInt;
|
|
}
|
|
}
|
|
HInstruction* vector = nullptr;
|
|
switch (org->GetKind()) {
|
|
case HInstruction::kNeg:
|
|
DCHECK(opb == nullptr);
|
|
GENERATE_VEC(
|
|
new (global_allocator_) HVecNeg(global_allocator_, opa, type, vector_length_),
|
|
new (global_allocator_) HNeg(type, opa));
|
|
case HInstruction::kNot:
|
|
DCHECK(opb == nullptr);
|
|
GENERATE_VEC(
|
|
new (global_allocator_) HVecNot(global_allocator_, opa, type, vector_length_),
|
|
new (global_allocator_) HNot(type, opa));
|
|
case HInstruction::kBooleanNot:
|
|
DCHECK(opb == nullptr);
|
|
GENERATE_VEC(
|
|
new (global_allocator_) HVecNot(global_allocator_, opa, type, vector_length_),
|
|
new (global_allocator_) HBooleanNot(opa));
|
|
case HInstruction::kTypeConversion:
|
|
DCHECK(opb == nullptr);
|
|
GENERATE_VEC(
|
|
new (global_allocator_) HVecCnv(global_allocator_, opa, type, vector_length_),
|
|
new (global_allocator_) HTypeConversion(type, opa, kNoDexPc));
|
|
case HInstruction::kAdd:
|
|
GENERATE_VEC(
|
|
new (global_allocator_) HVecAdd(global_allocator_, opa, opb, type, vector_length_),
|
|
new (global_allocator_) HAdd(type, opa, opb));
|
|
case HInstruction::kSub:
|
|
GENERATE_VEC(
|
|
new (global_allocator_) HVecSub(global_allocator_, opa, opb, type, vector_length_),
|
|
new (global_allocator_) HSub(type, opa, opb));
|
|
case HInstruction::kMul:
|
|
GENERATE_VEC(
|
|
new (global_allocator_) HVecMul(global_allocator_, opa, opb, type, vector_length_),
|
|
new (global_allocator_) HMul(type, opa, opb));
|
|
case HInstruction::kDiv:
|
|
GENERATE_VEC(
|
|
new (global_allocator_) HVecDiv(global_allocator_, opa, opb, type, vector_length_),
|
|
new (global_allocator_) HDiv(type, opa, opb, kNoDexPc));
|
|
case HInstruction::kAnd:
|
|
GENERATE_VEC(
|
|
new (global_allocator_) HVecAnd(global_allocator_, opa, opb, type, vector_length_),
|
|
new (global_allocator_) HAnd(type, opa, opb));
|
|
case HInstruction::kOr:
|
|
GENERATE_VEC(
|
|
new (global_allocator_) HVecOr(global_allocator_, opa, opb, type, vector_length_),
|
|
new (global_allocator_) HOr(type, opa, opb));
|
|
case HInstruction::kXor:
|
|
GENERATE_VEC(
|
|
new (global_allocator_) HVecXor(global_allocator_, opa, opb, type, vector_length_),
|
|
new (global_allocator_) HXor(type, opa, opb));
|
|
case HInstruction::kShl:
|
|
GENERATE_VEC(
|
|
new (global_allocator_) HVecShl(global_allocator_, opa, opb, type, vector_length_),
|
|
new (global_allocator_) HShl(type, opa, opb));
|
|
case HInstruction::kShr:
|
|
GENERATE_VEC(
|
|
new (global_allocator_) HVecShr(global_allocator_, opa, opb, type, vector_length_),
|
|
new (global_allocator_) HShr(type, opa, opb));
|
|
case HInstruction::kUShr:
|
|
GENERATE_VEC(
|
|
new (global_allocator_) HVecUShr(global_allocator_, opa, opb, type, vector_length_),
|
|
new (global_allocator_) HUShr(type, opa, opb));
|
|
case HInstruction::kInvokeStaticOrDirect: {
|
|
HInvokeStaticOrDirect* invoke = org->AsInvokeStaticOrDirect();
|
|
if (vector_mode_ == kVector) {
|
|
switch (invoke->GetIntrinsic()) {
|
|
case Intrinsics::kMathAbsInt:
|
|
case Intrinsics::kMathAbsLong:
|
|
case Intrinsics::kMathAbsFloat:
|
|
case Intrinsics::kMathAbsDouble:
|
|
DCHECK(opb == nullptr);
|
|
vector = new (global_allocator_) HVecAbs(global_allocator_, opa, type, vector_length_);
|
|
break;
|
|
case Intrinsics::kMathMinIntInt:
|
|
case Intrinsics::kMathMinLongLong:
|
|
case Intrinsics::kMathMinFloatFloat:
|
|
case Intrinsics::kMathMinDoubleDouble: {
|
|
vector = new (global_allocator_)
|
|
HVecMin(global_allocator_, opa, opb, type, vector_length_, is_unsigned);
|
|
break;
|
|
}
|
|
case Intrinsics::kMathMaxIntInt:
|
|
case Intrinsics::kMathMaxLongLong:
|
|
case Intrinsics::kMathMaxFloatFloat:
|
|
case Intrinsics::kMathMaxDoubleDouble: {
|
|
vector = new (global_allocator_)
|
|
HVecMax(global_allocator_, opa, opb, type, vector_length_, is_unsigned);
|
|
break;
|
|
}
|
|
default:
|
|
LOG(FATAL) << "Unsupported SIMD intrinsic";
|
|
UNREACHABLE();
|
|
} // switch invoke
|
|
} else {
|
|
// In scalar code, simply clone the method invoke, and replace its operands with the
|
|
// corresponding new scalar instructions in the loop. The instruction will get an
|
|
// environment while being inserted from the instruction map in original program order.
|
|
DCHECK(vector_mode_ == kSequential);
|
|
size_t num_args = invoke->GetNumberOfArguments();
|
|
HInvokeStaticOrDirect* new_invoke = new (global_allocator_) HInvokeStaticOrDirect(
|
|
global_allocator_,
|
|
num_args,
|
|
invoke->GetType(),
|
|
invoke->GetDexPc(),
|
|
invoke->GetDexMethodIndex(),
|
|
invoke->GetResolvedMethod(),
|
|
invoke->GetDispatchInfo(),
|
|
invoke->GetInvokeType(),
|
|
invoke->GetTargetMethod(),
|
|
invoke->GetClinitCheckRequirement());
|
|
HInputsRef inputs = invoke->GetInputs();
|
|
size_t num_inputs = inputs.size();
|
|
DCHECK_LE(num_args, num_inputs);
|
|
DCHECK_EQ(num_inputs, new_invoke->GetInputs().size()); // both invokes agree
|
|
for (size_t index = 0; index < num_inputs; ++index) {
|
|
HInstruction* new_input = index < num_args
|
|
? vector_map_->Get(inputs[index])
|
|
: inputs[index]; // beyond arguments: just pass through
|
|
new_invoke->SetArgumentAt(index, new_input);
|
|
}
|
|
new_invoke->SetIntrinsic(invoke->GetIntrinsic(),
|
|
kNeedsEnvironmentOrCache,
|
|
kNoSideEffects,
|
|
kNoThrow);
|
|
vector = new_invoke;
|
|
}
|
|
break;
|
|
}
|
|
default:
|
|
break;
|
|
} // switch
|
|
CHECK(vector != nullptr) << "Unsupported SIMD operator";
|
|
vector_map_->Put(org, vector);
|
|
}
|
|
|
|
#undef GENERATE_VEC
|
|
|
|
//
|
|
// Vectorization idioms.
|
|
//
|
|
|
|
// Method recognizes the following idioms:
|
|
// rounding halving add (a + b + 1) >> 1 for unsigned/signed operands a, b
|
|
// regular halving add (a + b) >> 1 for unsigned/signed operands a, b
|
|
// Provided that the operands are promoted to a wider form to do the arithmetic and
|
|
// then cast back to narrower form, the idioms can be mapped into efficient SIMD
|
|
// implementation that operates directly in narrower form (plus one extra bit).
|
|
// TODO: current version recognizes implicit byte/short/char widening only;
|
|
// explicit widening from int to long could be added later.
|
|
bool HLoopOptimization::VectorizeHalvingAddIdiom(LoopNode* node,
|
|
HInstruction* instruction,
|
|
bool generate_code,
|
|
Primitive::Type type,
|
|
uint64_t restrictions) {
|
|
// Test for top level arithmetic shift right x >> 1 or logical shift right x >>> 1
|
|
// (note whether the sign bit in wider precision is shifted in has no effect
|
|
// on the narrow precision computed by the idiom).
|
|
int64_t distance = 0;
|
|
if ((instruction->IsShr() ||
|
|
instruction->IsUShr()) &&
|
|
IsInt64AndGet(instruction->InputAt(1), /*out*/ &distance) && distance == 1) {
|
|
// Test for (a + b + c) >> 1 for optional constant c.
|
|
HInstruction* a = nullptr;
|
|
HInstruction* b = nullptr;
|
|
int64_t c = 0;
|
|
if (IsAddConst(instruction->InputAt(0), /*out*/ &a, /*out*/ &b, /*out*/ &c)) {
|
|
DCHECK(a != nullptr && b != nullptr);
|
|
// Accept c == 1 (rounded) or c == 0 (not rounded).
|
|
bool is_rounded = false;
|
|
if (c == 1) {
|
|
is_rounded = true;
|
|
} else if (c != 0) {
|
|
return false;
|
|
}
|
|
// Accept consistent zero or sign extension on operands a and b.
|
|
HInstruction* r = nullptr;
|
|
HInstruction* s = nullptr;
|
|
bool is_unsigned = false;
|
|
if (!IsNarrowerOperands(a, b, type, &r, &s, &is_unsigned)) {
|
|
return false;
|
|
}
|
|
// Deal with vector restrictions.
|
|
if ((!is_unsigned && HasVectorRestrictions(restrictions, kNoSignedHAdd)) ||
|
|
(!is_rounded && HasVectorRestrictions(restrictions, kNoUnroundedHAdd))) {
|
|
return false;
|
|
}
|
|
// Accept recognized halving add for vectorizable operands. Vectorized code uses the
|
|
// shorthand idiomatic operation. Sequential code uses the original scalar expressions.
|
|
DCHECK(r != nullptr && s != nullptr);
|
|
if (generate_code && vector_mode_ != kVector) { // de-idiom
|
|
r = instruction->InputAt(0);
|
|
s = instruction->InputAt(1);
|
|
}
|
|
if (VectorizeUse(node, r, generate_code, type, restrictions) &&
|
|
VectorizeUse(node, s, generate_code, type, restrictions)) {
|
|
if (generate_code) {
|
|
if (vector_mode_ == kVector) {
|
|
vector_map_->Put(instruction, new (global_allocator_) HVecHalvingAdd(
|
|
global_allocator_,
|
|
vector_map_->Get(r),
|
|
vector_map_->Get(s),
|
|
type,
|
|
vector_length_,
|
|
is_unsigned,
|
|
is_rounded));
|
|
} else {
|
|
GenerateVecOp(instruction, vector_map_->Get(r), vector_map_->Get(s), type);
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
//
|
|
// Vectorization heuristics.
|
|
//
|
|
|
|
bool HLoopOptimization::IsVectorizationProfitable(int64_t trip_count) {
|
|
// Current heuristic: non-empty body with sufficient number
|
|
// of iterations (if known).
|
|
// TODO: refine by looking at e.g. operation count, alignment, etc.
|
|
if (vector_length_ == 0) {
|
|
return false; // nothing found
|
|
} else if (0 < trip_count && trip_count < vector_length_) {
|
|
return false; // insufficient iterations
|
|
}
|
|
return true;
|
|
}
|
|
|
|
void HLoopOptimization::SetPeelingCandidate(int64_t trip_count ATTRIBUTE_UNUSED) {
|
|
// Current heuristic: none.
|
|
// TODO: implement
|
|
}
|
|
|
|
uint32_t HLoopOptimization::GetUnrollingFactor(HBasicBlock* block, int64_t trip_count) {
|
|
// Current heuristic: unroll by 2 on ARM64/X86 for large known trip
|
|
// counts and small loop bodies.
|
|
// TODO: refine with operation count, remaining iterations, etc.
|
|
// Artem had some really cool ideas for this already.
|
|
switch (compiler_driver_->GetInstructionSet()) {
|
|
case kArm64:
|
|
case kX86:
|
|
case kX86_64: {
|
|
size_t num_instructions = block->GetInstructions().CountSize();
|
|
if (num_instructions <= 10 && trip_count >= 4 * vector_length_) {
|
|
return 2;
|
|
}
|
|
return 1;
|
|
}
|
|
default:
|
|
return 1;
|
|
}
|
|
}
|
|
|
|
//
|
|
// Helpers.
|
|
//
|
|
|
|
bool HLoopOptimization::TrySetPhiInduction(HPhi* phi, bool restrict_uses) {
|
|
// Special case Phis that have equivalent in a debuggable setup. Our graph checker isn't
|
|
// smart enough to follow strongly connected components (and it's probably not worth
|
|
// it to make it so). See b/33775412.
|
|
if (graph_->IsDebuggable() && phi->HasEquivalentPhi()) {
|
|
return false;
|
|
}
|
|
DCHECK(iset_->empty());
|
|
ArenaSet<HInstruction*>* set = induction_range_.LookupCycle(phi);
|
|
if (set != nullptr) {
|
|
for (HInstruction* i : *set) {
|
|
// Check that, other than instructions that are no longer in the graph (removed earlier)
|
|
// each instruction is removable and, when restrict uses are requested, other than for phi,
|
|
// all uses are contained within the cycle.
|
|
if (!i->IsInBlock()) {
|
|
continue;
|
|
} else if (!i->IsRemovable()) {
|
|
return false;
|
|
} else if (i != phi && restrict_uses) {
|
|
for (const HUseListNode<HInstruction*>& use : i->GetUses()) {
|
|
if (set->find(use.GetUser()) == set->end()) {
|
|
return false;
|
|
}
|
|
}
|
|
}
|
|
iset_->insert(i); // copy
|
|
}
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
// Find: phi: Phi(init, addsub)
|
|
// s: SuspendCheck
|
|
// c: Condition(phi, bound)
|
|
// i: If(c)
|
|
// TODO: Find a less pattern matching approach?
|
|
bool HLoopOptimization::TrySetSimpleLoopHeader(HBasicBlock* block) {
|
|
DCHECK(iset_->empty());
|
|
HInstruction* phi = block->GetFirstPhi();
|
|
if (phi != nullptr &&
|
|
phi->GetNext() == nullptr &&
|
|
TrySetPhiInduction(phi->AsPhi(), /*restrict_uses*/ false)) {
|
|
HInstruction* s = block->GetFirstInstruction();
|
|
if (s != nullptr && s->IsSuspendCheck()) {
|
|
HInstruction* c = s->GetNext();
|
|
if (c != nullptr &&
|
|
c->IsCondition() &&
|
|
c->GetUses().HasExactlyOneElement() && // only used for termination
|
|
!c->HasEnvironmentUses()) { // unlikely, but not impossible
|
|
HInstruction* i = c->GetNext();
|
|
if (i != nullptr && i->IsIf() && i->InputAt(0) == c) {
|
|
iset_->insert(c);
|
|
iset_->insert(s);
|
|
return true;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
bool HLoopOptimization::IsEmptyBody(HBasicBlock* block) {
|
|
if (!block->GetPhis().IsEmpty()) {
|
|
return false;
|
|
}
|
|
for (HInstructionIterator it(block->GetInstructions()); !it.Done(); it.Advance()) {
|
|
HInstruction* instruction = it.Current();
|
|
if (!instruction->IsGoto() && iset_->find(instruction) == iset_->end()) {
|
|
return false;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
bool HLoopOptimization::IsUsedOutsideLoop(HLoopInformation* loop_info,
|
|
HInstruction* instruction) {
|
|
for (const HUseListNode<HInstruction*>& use : instruction->GetUses()) {
|
|
if (use.GetUser()->GetBlock()->GetLoopInformation() != loop_info) {
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
bool HLoopOptimization::IsOnlyUsedAfterLoop(HLoopInformation* loop_info,
|
|
HInstruction* instruction,
|
|
bool collect_loop_uses,
|
|
/*out*/ int32_t* use_count) {
|
|
for (const HUseListNode<HInstruction*>& use : instruction->GetUses()) {
|
|
HInstruction* user = use.GetUser();
|
|
if (iset_->find(user) == iset_->end()) { // not excluded?
|
|
HLoopInformation* other_loop_info = user->GetBlock()->GetLoopInformation();
|
|
if (other_loop_info != nullptr && other_loop_info->IsIn(*loop_info)) {
|
|
// If collect_loop_uses is set, simply keep adding those uses to the set.
|
|
// Otherwise, reject uses inside the loop that were not already in the set.
|
|
if (collect_loop_uses) {
|
|
iset_->insert(user);
|
|
continue;
|
|
}
|
|
return false;
|
|
}
|
|
++*use_count;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
bool HLoopOptimization::TryReplaceWithLastValue(HLoopInformation* loop_info,
|
|
HInstruction* instruction,
|
|
HBasicBlock* block) {
|
|
// Try to replace outside uses with the last value.
|
|
if (induction_range_.CanGenerateLastValue(instruction)) {
|
|
HInstruction* replacement = induction_range_.GenerateLastValue(instruction, graph_, block);
|
|
const HUseList<HInstruction*>& uses = instruction->GetUses();
|
|
for (auto it = uses.begin(), end = uses.end(); it != end;) {
|
|
HInstruction* user = it->GetUser();
|
|
size_t index = it->GetIndex();
|
|
++it; // increment before replacing
|
|
if (iset_->find(user) == iset_->end()) { // not excluded?
|
|
if (kIsDebugBuild) {
|
|
// We have checked earlier in 'IsOnlyUsedAfterLoop' that the use is after the loop.
|
|
HLoopInformation* other_loop_info = user->GetBlock()->GetLoopInformation();
|
|
CHECK(other_loop_info == nullptr || !other_loop_info->IsIn(*loop_info));
|
|
}
|
|
user->ReplaceInput(replacement, index);
|
|
induction_range_.Replace(user, instruction, replacement); // update induction
|
|
}
|
|
}
|
|
const HUseList<HEnvironment*>& env_uses = instruction->GetEnvUses();
|
|
for (auto it = env_uses.begin(), end = env_uses.end(); it != end;) {
|
|
HEnvironment* user = it->GetUser();
|
|
size_t index = it->GetIndex();
|
|
++it; // increment before replacing
|
|
if (iset_->find(user->GetHolder()) == iset_->end()) { // not excluded?
|
|
// Only update environment uses after the loop.
|
|
HLoopInformation* other_loop_info = user->GetHolder()->GetBlock()->GetLoopInformation();
|
|
if (other_loop_info == nullptr || !other_loop_info->IsIn(*loop_info)) {
|
|
user->RemoveAsUserOfInput(index);
|
|
user->SetRawEnvAt(index, replacement);
|
|
replacement->AddEnvUseAt(user, index);
|
|
}
|
|
}
|
|
}
|
|
induction_simplication_count_++;
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
bool HLoopOptimization::TryAssignLastValue(HLoopInformation* loop_info,
|
|
HInstruction* instruction,
|
|
HBasicBlock* block,
|
|
bool collect_loop_uses) {
|
|
// Assigning the last value is always successful if there are no uses.
|
|
// Otherwise, it succeeds in a no early-exit loop by generating the
|
|
// proper last value assignment.
|
|
int32_t use_count = 0;
|
|
return IsOnlyUsedAfterLoop(loop_info, instruction, collect_loop_uses, &use_count) &&
|
|
(use_count == 0 ||
|
|
(!IsEarlyExit(loop_info) && TryReplaceWithLastValue(loop_info, instruction, block)));
|
|
}
|
|
|
|
void HLoopOptimization::RemoveDeadInstructions(const HInstructionList& list) {
|
|
for (HBackwardInstructionIterator i(list); !i.Done(); i.Advance()) {
|
|
HInstruction* instruction = i.Current();
|
|
if (instruction->IsDeadAndRemovable()) {
|
|
simplified_ = true;
|
|
instruction->GetBlock()->RemoveInstructionOrPhi(instruction);
|
|
}
|
|
}
|
|
}
|
|
|
|
bool HLoopOptimization::CanRemoveCycle() {
|
|
for (HInstruction* i : *iset_) {
|
|
// We can never remove instructions that have environment
|
|
// uses when we compile 'debuggable'.
|
|
if (i->HasEnvironmentUses() && graph_->IsDebuggable()) {
|
|
return false;
|
|
}
|
|
// A deoptimization should never have an environment input removed.
|
|
for (const HUseListNode<HEnvironment*>& use : i->GetEnvUses()) {
|
|
if (use.GetUser()->GetHolder()->IsDeoptimize()) {
|
|
return false;
|
|
}
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
} // namespace art
|