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1373 lines
59 KiB
1373 lines
59 KiB
/*
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* Copyright (C) 2015 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "induction_var_range.h"
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#include <limits>
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namespace art {
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/** Returns true if 64-bit constant fits in 32-bit constant. */
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static bool CanLongValueFitIntoInt(int64_t c) {
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return std::numeric_limits<int32_t>::min() <= c && c <= std::numeric_limits<int32_t>::max();
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}
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/** Returns true if 32-bit addition can be done safely. */
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static bool IsSafeAdd(int32_t c1, int32_t c2) {
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return CanLongValueFitIntoInt(static_cast<int64_t>(c1) + static_cast<int64_t>(c2));
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}
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/** Returns true if 32-bit subtraction can be done safely. */
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static bool IsSafeSub(int32_t c1, int32_t c2) {
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return CanLongValueFitIntoInt(static_cast<int64_t>(c1) - static_cast<int64_t>(c2));
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}
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/** Returns true if 32-bit multiplication can be done safely. */
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static bool IsSafeMul(int32_t c1, int32_t c2) {
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return CanLongValueFitIntoInt(static_cast<int64_t>(c1) * static_cast<int64_t>(c2));
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}
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/** Returns true if 32-bit division can be done safely. */
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static bool IsSafeDiv(int32_t c1, int32_t c2) {
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return c2 != 0 && CanLongValueFitIntoInt(static_cast<int64_t>(c1) / static_cast<int64_t>(c2));
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}
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/** Computes a * b for a,b > 0 (at least until first overflow happens). */
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static int64_t SafeMul(int64_t a, int64_t b, /*out*/ bool* overflow) {
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if (a > 0 && b > 0 && a > (std::numeric_limits<int64_t>::max() / b)) {
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*overflow = true;
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}
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return a * b;
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}
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/** Returns b^e for b,e > 0. Sets overflow if arithmetic wrap-around occurred. */
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static int64_t IntPow(int64_t b, int64_t e, /*out*/ bool* overflow) {
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DCHECK_LT(0, b);
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DCHECK_LT(0, e);
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int64_t pow = 1;
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while (e) {
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if (e & 1) {
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pow = SafeMul(pow, b, overflow);
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}
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e >>= 1;
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if (e) {
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b = SafeMul(b, b, overflow);
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}
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}
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return pow;
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}
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/** Hunts "under the hood" for a suitable instruction at the hint. */
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static bool IsMaxAtHint(
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HInstruction* instruction, HInstruction* hint, /*out*/HInstruction** suitable) {
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if (instruction->IsMin()) {
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// For MIN(x, y), return most suitable x or y as maximum.
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return IsMaxAtHint(instruction->InputAt(0), hint, suitable) ||
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IsMaxAtHint(instruction->InputAt(1), hint, suitable);
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} else {
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*suitable = instruction;
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return HuntForDeclaration(instruction) == hint;
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}
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}
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/** Post-analysis simplification of a minimum value that makes the bound more useful to clients. */
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static InductionVarRange::Value SimplifyMin(InductionVarRange::Value v) {
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if (v.is_known && v.a_constant == 1 && v.b_constant <= 0) {
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// If a == 1, instruction >= 0 and b <= 0, just return the constant b.
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// No arithmetic wrap-around can occur.
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if (IsGEZero(v.instruction)) {
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return InductionVarRange::Value(v.b_constant);
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}
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}
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return v;
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}
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/** Post-analysis simplification of a maximum value that makes the bound more useful to clients. */
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static InductionVarRange::Value SimplifyMax(InductionVarRange::Value v, HInstruction* hint) {
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if (v.is_known && v.a_constant >= 1) {
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// An upper bound a * (length / a) + b, where a >= 1, can be conservatively rewritten as
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// length + b because length >= 0 is true.
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int64_t value;
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if (v.instruction->IsDiv() &&
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v.instruction->InputAt(0)->IsArrayLength() &&
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IsInt64AndGet(v.instruction->InputAt(1), &value) && v.a_constant == value) {
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return InductionVarRange::Value(v.instruction->InputAt(0), 1, v.b_constant);
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}
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// If a == 1, the most suitable one suffices as maximum value.
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HInstruction* suitable = nullptr;
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if (v.a_constant == 1 && IsMaxAtHint(v.instruction, hint, &suitable)) {
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return InductionVarRange::Value(suitable, 1, v.b_constant);
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}
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}
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return v;
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}
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/** Tests for a constant value. */
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static bool IsConstantValue(InductionVarRange::Value v) {
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return v.is_known && v.a_constant == 0;
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}
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/** Corrects a value for type to account for arithmetic wrap-around in lower precision. */
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static InductionVarRange::Value CorrectForType(InductionVarRange::Value v, DataType::Type type) {
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switch (type) {
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case DataType::Type::kUint8:
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case DataType::Type::kInt8:
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case DataType::Type::kUint16:
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case DataType::Type::kInt16: {
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// Constants within range only.
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// TODO: maybe some room for improvement, like allowing widening conversions
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int32_t min = DataType::MinValueOfIntegralType(type);
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int32_t max = DataType::MaxValueOfIntegralType(type);
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return (IsConstantValue(v) && min <= v.b_constant && v.b_constant <= max)
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? v
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: InductionVarRange::Value();
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}
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default:
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return v;
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}
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}
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/** Inserts 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(block->GetLastInstruction() != nullptr) << block->GetBlockId();
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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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/** Obtains loop's control instruction. */
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static HInstruction* GetLoopControl(HLoopInformation* loop) {
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DCHECK(loop != nullptr);
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return loop->GetHeader()->GetLastInstruction();
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}
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//
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// Public class methods.
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//
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InductionVarRange::InductionVarRange(HInductionVarAnalysis* induction_analysis)
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: induction_analysis_(induction_analysis),
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chase_hint_(nullptr) {
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DCHECK(induction_analysis != nullptr);
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}
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bool InductionVarRange::GetInductionRange(HInstruction* context,
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HInstruction* instruction,
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HInstruction* chase_hint,
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/*out*/Value* min_val,
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/*out*/Value* max_val,
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/*out*/bool* needs_finite_test) {
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HLoopInformation* loop = nullptr;
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HInductionVarAnalysis::InductionInfo* info = nullptr;
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HInductionVarAnalysis::InductionInfo* trip = nullptr;
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if (!HasInductionInfo(context, instruction, &loop, &info, &trip)) {
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return false;
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}
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// Type int or lower (this is not too restrictive since intended clients, like
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// bounds check elimination, will have truncated higher precision induction
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// at their use point already).
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switch (info->type) {
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case DataType::Type::kUint8:
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case DataType::Type::kInt8:
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case DataType::Type::kUint16:
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case DataType::Type::kInt16:
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case DataType::Type::kInt32:
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break;
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default:
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return false;
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}
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// Find range.
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chase_hint_ = chase_hint;
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bool in_body = context->GetBlock() != loop->GetHeader();
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int64_t stride_value = 0;
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*min_val = SimplifyMin(GetVal(info, trip, in_body, /* is_min= */ true));
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*max_val = SimplifyMax(GetVal(info, trip, in_body, /* is_min= */ false), chase_hint);
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*needs_finite_test = NeedsTripCount(info, &stride_value) && IsUnsafeTripCount(trip);
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chase_hint_ = nullptr;
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// Retry chasing constants for wrap-around (merge sensitive).
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if (!min_val->is_known && info->induction_class == HInductionVarAnalysis::kWrapAround) {
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*min_val = SimplifyMin(GetVal(info, trip, in_body, /* is_min= */ true));
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}
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return true;
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}
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bool InductionVarRange::CanGenerateRange(HInstruction* context,
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HInstruction* instruction,
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/*out*/bool* needs_finite_test,
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/*out*/bool* needs_taken_test) {
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bool is_last_value = false;
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int64_t stride_value = 0;
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return GenerateRangeOrLastValue(context,
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instruction,
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is_last_value,
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nullptr,
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nullptr,
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nullptr,
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nullptr,
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nullptr, // nothing generated yet
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&stride_value,
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needs_finite_test,
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needs_taken_test)
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&& (stride_value == -1 ||
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stride_value == 0 ||
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stride_value == 1); // avoid arithmetic wrap-around anomalies.
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}
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void InductionVarRange::GenerateRange(HInstruction* context,
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HInstruction* instruction,
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HGraph* graph,
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HBasicBlock* block,
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/*out*/HInstruction** lower,
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/*out*/HInstruction** upper) {
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bool is_last_value = false;
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int64_t stride_value = 0;
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bool b1, b2; // unused
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if (!GenerateRangeOrLastValue(context,
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instruction,
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is_last_value,
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graph,
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block,
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lower,
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upper,
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nullptr,
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&stride_value,
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&b1,
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&b2)) {
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LOG(FATAL) << "Failed precondition: CanGenerateRange()";
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}
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}
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HInstruction* InductionVarRange::GenerateTakenTest(HInstruction* context,
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HGraph* graph,
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HBasicBlock* block) {
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HInstruction* taken_test = nullptr;
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bool is_last_value = false;
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int64_t stride_value = 0;
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bool b1, b2; // unused
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if (!GenerateRangeOrLastValue(context,
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context,
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is_last_value,
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graph,
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block,
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nullptr,
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nullptr,
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&taken_test,
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&stride_value,
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&b1,
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&b2)) {
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LOG(FATAL) << "Failed precondition: CanGenerateRange()";
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}
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return taken_test;
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}
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bool InductionVarRange::CanGenerateLastValue(HInstruction* instruction) {
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bool is_last_value = true;
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int64_t stride_value = 0;
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bool needs_finite_test = false;
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bool needs_taken_test = false;
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return GenerateRangeOrLastValue(instruction,
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instruction,
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is_last_value,
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nullptr,
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nullptr,
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nullptr,
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nullptr,
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nullptr, // nothing generated yet
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&stride_value,
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&needs_finite_test,
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&needs_taken_test)
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&& !needs_finite_test && !needs_taken_test;
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}
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HInstruction* InductionVarRange::GenerateLastValue(HInstruction* instruction,
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HGraph* graph,
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HBasicBlock* block) {
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HInstruction* last_value = nullptr;
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bool is_last_value = true;
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int64_t stride_value = 0;
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bool b1, b2; // unused
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if (!GenerateRangeOrLastValue(instruction,
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instruction,
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is_last_value,
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graph,
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block,
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&last_value,
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&last_value,
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nullptr,
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&stride_value,
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&b1,
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&b2)) {
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LOG(FATAL) << "Failed precondition: CanGenerateLastValue()";
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}
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return last_value;
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}
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void InductionVarRange::Replace(HInstruction* instruction,
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HInstruction* fetch,
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HInstruction* replacement) {
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for (HLoopInformation* lp = instruction->GetBlock()->GetLoopInformation(); // closest enveloping loop
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lp != nullptr;
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lp = lp->GetPreHeader()->GetLoopInformation()) {
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// Update instruction's information.
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ReplaceInduction(induction_analysis_->LookupInfo(lp, instruction), fetch, replacement);
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// Update loop's trip-count information.
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ReplaceInduction(induction_analysis_->LookupInfo(lp, GetLoopControl(lp)), fetch, replacement);
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}
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}
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bool InductionVarRange::IsFinite(HLoopInformation* loop, /*out*/ int64_t* trip_count) const {
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bool is_constant_unused = false;
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return CheckForFiniteAndConstantProps(loop, &is_constant_unused, trip_count);
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}
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bool InductionVarRange::HasKnownTripCount(HLoopInformation* loop,
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/*out*/ int64_t* trip_count) const {
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bool is_constant = false;
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CheckForFiniteAndConstantProps(loop, &is_constant, trip_count);
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return is_constant;
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}
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bool InductionVarRange::IsUnitStride(HInstruction* context,
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HInstruction* instruction,
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HGraph* graph,
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/*out*/ HInstruction** offset) const {
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HLoopInformation* loop = nullptr;
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HInductionVarAnalysis::InductionInfo* info = nullptr;
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HInductionVarAnalysis::InductionInfo* trip = nullptr;
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if (HasInductionInfo(context, instruction, &loop, &info, &trip)) {
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if (info->induction_class == HInductionVarAnalysis::kLinear &&
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!HInductionVarAnalysis::IsNarrowingLinear(info)) {
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int64_t stride_value = 0;
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if (IsConstant(info->op_a, kExact, &stride_value) && stride_value == 1) {
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int64_t off_value = 0;
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if (IsConstant(info->op_b, kExact, &off_value)) {
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*offset = graph->GetConstant(info->op_b->type, off_value);
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} else if (info->op_b->operation == HInductionVarAnalysis::kFetch) {
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*offset = info->op_b->fetch;
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} else {
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return false;
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}
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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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HInstruction* InductionVarRange::GenerateTripCount(HLoopInformation* loop,
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HGraph* graph,
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HBasicBlock* block) {
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HInductionVarAnalysis::InductionInfo *trip =
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induction_analysis_->LookupInfo(loop, GetLoopControl(loop));
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if (trip != nullptr && !IsUnsafeTripCount(trip)) {
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HInstruction* taken_test = nullptr;
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HInstruction* trip_expr = nullptr;
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if (IsBodyTripCount(trip)) {
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if (!GenerateCode(trip->op_b, nullptr, graph, block, &taken_test, false, false)) {
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return nullptr;
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}
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}
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if (GenerateCode(trip->op_a, nullptr, graph, block, &trip_expr, false, false)) {
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if (taken_test != nullptr) {
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HInstruction* zero = graph->GetConstant(trip->type, 0);
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ArenaAllocator* allocator = graph->GetAllocator();
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trip_expr = Insert(block, new (allocator) HSelect(taken_test, trip_expr, zero, kNoDexPc));
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}
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return trip_expr;
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}
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}
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return nullptr;
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}
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//
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// Private class methods.
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//
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bool InductionVarRange::CheckForFiniteAndConstantProps(HLoopInformation* loop,
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/*out*/ bool* is_constant,
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/*out*/ int64_t* trip_count) const {
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HInductionVarAnalysis::InductionInfo *trip =
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induction_analysis_->LookupInfo(loop, GetLoopControl(loop));
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if (trip != nullptr && !IsUnsafeTripCount(trip)) {
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*is_constant = IsConstant(trip->op_a, kExact, trip_count);
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return true;
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}
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return false;
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}
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bool InductionVarRange::IsConstant(HInductionVarAnalysis::InductionInfo* info,
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ConstantRequest request,
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/*out*/ int64_t* value) const {
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if (info != nullptr) {
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// A direct 32-bit or 64-bit constant fetch. This immediately satisfies
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// any of the three requests (kExact, kAtMost, and KAtLeast).
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if (info->induction_class == HInductionVarAnalysis::kInvariant &&
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info->operation == HInductionVarAnalysis::kFetch) {
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if (IsInt64AndGet(info->fetch, value)) {
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return true;
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}
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}
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// Try range analysis on the invariant, only accept a proper range
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// to avoid arithmetic wrap-around anomalies.
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Value min_val = GetVal(info, nullptr, /* in_body= */ true, /* is_min= */ true);
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Value max_val = GetVal(info, nullptr, /* in_body= */ true, /* is_min= */ false);
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if (IsConstantValue(min_val) &&
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IsConstantValue(max_val) && min_val.b_constant <= max_val.b_constant) {
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if ((request == kExact && min_val.b_constant == max_val.b_constant) || request == kAtMost) {
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*value = max_val.b_constant;
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return true;
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} else if (request == kAtLeast) {
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*value = min_val.b_constant;
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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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bool InductionVarRange::HasInductionInfo(
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HInstruction* context,
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HInstruction* instruction,
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/*out*/ HLoopInformation** loop,
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/*out*/ HInductionVarAnalysis::InductionInfo** info,
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/*out*/ HInductionVarAnalysis::InductionInfo** trip) const {
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DCHECK(context != nullptr);
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DCHECK(context->GetBlock() != nullptr);
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HLoopInformation* lp = context->GetBlock()->GetLoopInformation(); // closest enveloping loop
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if (lp != nullptr) {
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HInductionVarAnalysis::InductionInfo* i = induction_analysis_->LookupInfo(lp, instruction);
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if (i != nullptr) {
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*loop = lp;
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*info = i;
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*trip = induction_analysis_->LookupInfo(lp, GetLoopControl(lp));
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return true;
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}
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}
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return false;
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}
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bool InductionVarRange::IsWellBehavedTripCount(HInductionVarAnalysis::InductionInfo* trip) const {
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if (trip != nullptr) {
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// Both bounds that define a trip-count are well-behaved if they either are not defined
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// in any loop, or are contained in a proper interval. This allows finding the min/max
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// of an expression by chasing outward.
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InductionVarRange range(induction_analysis_);
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HInductionVarAnalysis::InductionInfo* lower = trip->op_b->op_a;
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HInductionVarAnalysis::InductionInfo* upper = trip->op_b->op_b;
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int64_t not_used = 0;
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return (!HasFetchInLoop(lower) || range.IsConstant(lower, kAtLeast, ¬_used)) &&
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(!HasFetchInLoop(upper) || range.IsConstant(upper, kAtLeast, ¬_used));
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}
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return true;
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}
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|
|
bool InductionVarRange::HasFetchInLoop(HInductionVarAnalysis::InductionInfo* info) const {
|
|
if (info != nullptr) {
|
|
if (info->induction_class == HInductionVarAnalysis::kInvariant &&
|
|
info->operation == HInductionVarAnalysis::kFetch) {
|
|
return info->fetch->GetBlock()->GetLoopInformation() != nullptr;
|
|
}
|
|
return HasFetchInLoop(info->op_a) || HasFetchInLoop(info->op_b);
|
|
}
|
|
return false;
|
|
}
|
|
|
|
bool InductionVarRange::NeedsTripCount(HInductionVarAnalysis::InductionInfo* info,
|
|
int64_t* stride_value) const {
|
|
if (info != nullptr) {
|
|
if (info->induction_class == HInductionVarAnalysis::kLinear) {
|
|
return IsConstant(info->op_a, kExact, stride_value);
|
|
} else if (info->induction_class == HInductionVarAnalysis::kPolynomial) {
|
|
return NeedsTripCount(info->op_a, stride_value);
|
|
} else if (info->induction_class == HInductionVarAnalysis::kWrapAround) {
|
|
return NeedsTripCount(info->op_b, stride_value);
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
bool InductionVarRange::IsBodyTripCount(HInductionVarAnalysis::InductionInfo* trip) const {
|
|
if (trip != nullptr) {
|
|
if (trip->induction_class == HInductionVarAnalysis::kInvariant) {
|
|
return trip->operation == HInductionVarAnalysis::kTripCountInBody ||
|
|
trip->operation == HInductionVarAnalysis::kTripCountInBodyUnsafe;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
bool InductionVarRange::IsUnsafeTripCount(HInductionVarAnalysis::InductionInfo* trip) const {
|
|
if (trip != nullptr) {
|
|
if (trip->induction_class == HInductionVarAnalysis::kInvariant) {
|
|
return trip->operation == HInductionVarAnalysis::kTripCountInBodyUnsafe ||
|
|
trip->operation == HInductionVarAnalysis::kTripCountInLoopUnsafe;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
InductionVarRange::Value InductionVarRange::GetLinear(HInductionVarAnalysis::InductionInfo* info,
|
|
HInductionVarAnalysis::InductionInfo* trip,
|
|
bool in_body,
|
|
bool is_min) const {
|
|
DCHECK(info != nullptr);
|
|
DCHECK_EQ(info->induction_class, HInductionVarAnalysis::kLinear);
|
|
// Detect common situation where an offset inside the trip-count cancels out during range
|
|
// analysis (finding max a * (TC - 1) + OFFSET for a == 1 and TC = UPPER - OFFSET or finding
|
|
// min a * (TC - 1) + OFFSET for a == -1 and TC = OFFSET - UPPER) to avoid losing information
|
|
// with intermediate results that only incorporate single instructions.
|
|
if (trip != nullptr) {
|
|
HInductionVarAnalysis::InductionInfo* trip_expr = trip->op_a;
|
|
if (trip_expr->type == info->type && trip_expr->operation == HInductionVarAnalysis::kSub) {
|
|
int64_t stride_value = 0;
|
|
if (IsConstant(info->op_a, kExact, &stride_value)) {
|
|
if (!is_min && stride_value == 1) {
|
|
// Test original trip's negative operand (trip_expr->op_b) against offset of induction.
|
|
if (HInductionVarAnalysis::InductionEqual(trip_expr->op_b, info->op_b)) {
|
|
// Analyze cancelled trip with just the positive operand (trip_expr->op_a).
|
|
HInductionVarAnalysis::InductionInfo cancelled_trip(
|
|
trip->induction_class,
|
|
trip->operation,
|
|
trip_expr->op_a,
|
|
trip->op_b,
|
|
nullptr,
|
|
trip->type);
|
|
return GetVal(&cancelled_trip, trip, in_body, is_min);
|
|
}
|
|
} else if (is_min && stride_value == -1) {
|
|
// Test original trip's positive operand (trip_expr->op_a) against offset of induction.
|
|
if (HInductionVarAnalysis::InductionEqual(trip_expr->op_a, info->op_b)) {
|
|
// Analyze cancelled trip with just the negative operand (trip_expr->op_b).
|
|
HInductionVarAnalysis::InductionInfo neg(
|
|
HInductionVarAnalysis::kInvariant,
|
|
HInductionVarAnalysis::kNeg,
|
|
nullptr,
|
|
trip_expr->op_b,
|
|
nullptr,
|
|
trip->type);
|
|
HInductionVarAnalysis::InductionInfo cancelled_trip(
|
|
trip->induction_class, trip->operation, &neg, trip->op_b, nullptr, trip->type);
|
|
return SubValue(Value(0), GetVal(&cancelled_trip, trip, in_body, !is_min));
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
// General rule of linear induction a * i + b, for normalized 0 <= i < TC.
|
|
return AddValue(GetMul(info->op_a, trip, trip, in_body, is_min),
|
|
GetVal(info->op_b, trip, in_body, is_min));
|
|
}
|
|
|
|
InductionVarRange::Value InductionVarRange::GetPolynomial(HInductionVarAnalysis::InductionInfo* info,
|
|
HInductionVarAnalysis::InductionInfo* trip,
|
|
bool in_body,
|
|
bool is_min) const {
|
|
DCHECK(info != nullptr);
|
|
DCHECK_EQ(info->induction_class, HInductionVarAnalysis::kPolynomial);
|
|
int64_t a = 0;
|
|
int64_t b = 0;
|
|
if (IsConstant(info->op_a->op_a, kExact, &a) && CanLongValueFitIntoInt(a) && a >= 0 &&
|
|
IsConstant(info->op_a->op_b, kExact, &b) && CanLongValueFitIntoInt(b) && b >= 0) {
|
|
// Evaluate bounds on sum_i=0^m-1(a * i + b) + c with a,b >= 0 for
|
|
// maximum index value m as a * (m * (m-1)) / 2 + b * m + c.
|
|
Value c = GetVal(info->op_b, trip, in_body, is_min);
|
|
if (is_min) {
|
|
return c;
|
|
} else {
|
|
Value m = GetVal(trip, trip, in_body, is_min);
|
|
Value t = DivValue(MulValue(m, SubValue(m, Value(1))), Value(2));
|
|
Value x = MulValue(Value(a), t);
|
|
Value y = MulValue(Value(b), m);
|
|
return AddValue(AddValue(x, y), c);
|
|
}
|
|
}
|
|
return Value();
|
|
}
|
|
|
|
InductionVarRange::Value InductionVarRange::GetGeometric(HInductionVarAnalysis::InductionInfo* info,
|
|
HInductionVarAnalysis::InductionInfo* trip,
|
|
bool in_body,
|
|
bool is_min) const {
|
|
DCHECK(info != nullptr);
|
|
DCHECK_EQ(info->induction_class, HInductionVarAnalysis::kGeometric);
|
|
int64_t a = 0;
|
|
int64_t f = 0;
|
|
if (IsConstant(info->op_a, kExact, &a) &&
|
|
CanLongValueFitIntoInt(a) &&
|
|
IsInt64AndGet(info->fetch, &f) && f >= 1) {
|
|
// Conservative bounds on a * f^-i + b with f >= 1 can be computed without
|
|
// trip count. Other forms would require a much more elaborate evaluation.
|
|
const bool is_min_a = a >= 0 ? is_min : !is_min;
|
|
if (info->operation == HInductionVarAnalysis::kDiv) {
|
|
Value b = GetVal(info->op_b, trip, in_body, is_min);
|
|
return is_min_a ? b : AddValue(Value(a), b);
|
|
}
|
|
}
|
|
return Value();
|
|
}
|
|
|
|
InductionVarRange::Value InductionVarRange::GetFetch(HInstruction* instruction,
|
|
HInductionVarAnalysis::InductionInfo* trip,
|
|
bool in_body,
|
|
bool is_min) const {
|
|
// Special case when chasing constants: single instruction that denotes trip count in the
|
|
// loop-body is minimal 1 and maximal, with safe trip-count, max int,
|
|
if (chase_hint_ == nullptr && in_body && trip != nullptr && instruction == trip->op_a->fetch) {
|
|
if (is_min) {
|
|
return Value(1);
|
|
} else if (!instruction->IsConstant() && !IsUnsafeTripCount(trip)) {
|
|
return Value(std::numeric_limits<int32_t>::max());
|
|
}
|
|
}
|
|
// Unless at a constant or hint, chase the instruction a bit deeper into the HIR tree, so that
|
|
// it becomes more likely range analysis will compare the same instructions as terminal nodes.
|
|
int64_t value;
|
|
if (IsInt64AndGet(instruction, &value) && CanLongValueFitIntoInt(value)) {
|
|
// Proper constant reveals best information.
|
|
return Value(static_cast<int32_t>(value));
|
|
} else if (instruction == chase_hint_) {
|
|
// At hint, fetch is represented by itself.
|
|
return Value(instruction, 1, 0);
|
|
} else if (instruction->IsAdd()) {
|
|
// Incorporate suitable constants in the chased value.
|
|
if (IsInt64AndGet(instruction->InputAt(0), &value) && CanLongValueFitIntoInt(value)) {
|
|
return AddValue(Value(static_cast<int32_t>(value)),
|
|
GetFetch(instruction->InputAt(1), trip, in_body, is_min));
|
|
} else if (IsInt64AndGet(instruction->InputAt(1), &value) && CanLongValueFitIntoInt(value)) {
|
|
return AddValue(GetFetch(instruction->InputAt(0), trip, in_body, is_min),
|
|
Value(static_cast<int32_t>(value)));
|
|
}
|
|
} else if (instruction->IsSub()) {
|
|
// Incorporate suitable constants in the chased value.
|
|
if (IsInt64AndGet(instruction->InputAt(0), &value) && CanLongValueFitIntoInt(value)) {
|
|
return SubValue(Value(static_cast<int32_t>(value)),
|
|
GetFetch(instruction->InputAt(1), trip, in_body, !is_min));
|
|
} else if (IsInt64AndGet(instruction->InputAt(1), &value) && CanLongValueFitIntoInt(value)) {
|
|
return SubValue(GetFetch(instruction->InputAt(0), trip, in_body, is_min),
|
|
Value(static_cast<int32_t>(value)));
|
|
}
|
|
} else if (instruction->IsArrayLength()) {
|
|
// Exploit length properties when chasing constants or chase into a new array declaration.
|
|
if (chase_hint_ == nullptr) {
|
|
return is_min ? Value(0) : Value(std::numeric_limits<int32_t>::max());
|
|
} else if (instruction->InputAt(0)->IsNewArray()) {
|
|
return GetFetch(instruction->InputAt(0)->AsNewArray()->GetLength(), trip, in_body, is_min);
|
|
}
|
|
} else if (instruction->IsTypeConversion()) {
|
|
// Since analysis is 32-bit (or narrower), chase beyond widening along the path.
|
|
// For example, this discovers the length in: for (long i = 0; i < a.length; i++);
|
|
if (instruction->AsTypeConversion()->GetInputType() == DataType::Type::kInt32 &&
|
|
instruction->AsTypeConversion()->GetResultType() == DataType::Type::kInt64) {
|
|
return GetFetch(instruction->InputAt(0), trip, in_body, is_min);
|
|
}
|
|
}
|
|
// Chase an invariant fetch that is defined by an outer loop if the trip-count used
|
|
// so far is well-behaved in both bounds and the next trip-count is safe.
|
|
// Example:
|
|
// for (int i = 0; i <= 100; i++) // safe
|
|
// for (int j = 0; j <= i; j++) // well-behaved
|
|
// j is in range [0, i ] (if i is chase hint)
|
|
// or in range [0, 100] (otherwise)
|
|
HLoopInformation* next_loop = nullptr;
|
|
HInductionVarAnalysis::InductionInfo* next_info = nullptr;
|
|
HInductionVarAnalysis::InductionInfo* next_trip = nullptr;
|
|
bool next_in_body = true; // inner loop is always in body of outer loop
|
|
if (HasInductionInfo(instruction, instruction, &next_loop, &next_info, &next_trip) &&
|
|
IsWellBehavedTripCount(trip) &&
|
|
!IsUnsafeTripCount(next_trip)) {
|
|
return GetVal(next_info, next_trip, next_in_body, is_min);
|
|
}
|
|
// Fetch is represented by itself.
|
|
return Value(instruction, 1, 0);
|
|
}
|
|
|
|
InductionVarRange::Value InductionVarRange::GetVal(HInductionVarAnalysis::InductionInfo* info,
|
|
HInductionVarAnalysis::InductionInfo* trip,
|
|
bool in_body,
|
|
bool is_min) const {
|
|
if (info != nullptr) {
|
|
switch (info->induction_class) {
|
|
case HInductionVarAnalysis::kInvariant:
|
|
// Invariants.
|
|
switch (info->operation) {
|
|
case HInductionVarAnalysis::kAdd:
|
|
return AddValue(GetVal(info->op_a, trip, in_body, is_min),
|
|
GetVal(info->op_b, trip, in_body, is_min));
|
|
case HInductionVarAnalysis::kSub: // second reversed!
|
|
return SubValue(GetVal(info->op_a, trip, in_body, is_min),
|
|
GetVal(info->op_b, trip, in_body, !is_min));
|
|
case HInductionVarAnalysis::kNeg: // second reversed!
|
|
return SubValue(Value(0),
|
|
GetVal(info->op_b, trip, in_body, !is_min));
|
|
case HInductionVarAnalysis::kMul:
|
|
return GetMul(info->op_a, info->op_b, trip, in_body, is_min);
|
|
case HInductionVarAnalysis::kDiv:
|
|
return GetDiv(info->op_a, info->op_b, trip, in_body, is_min);
|
|
case HInductionVarAnalysis::kRem:
|
|
return GetRem(info->op_a, info->op_b);
|
|
case HInductionVarAnalysis::kXor:
|
|
return GetXor(info->op_a, info->op_b);
|
|
case HInductionVarAnalysis::kFetch:
|
|
return GetFetch(info->fetch, trip, in_body, is_min);
|
|
case HInductionVarAnalysis::kTripCountInLoop:
|
|
case HInductionVarAnalysis::kTripCountInLoopUnsafe:
|
|
if (!in_body && !is_min) { // one extra!
|
|
return GetVal(info->op_a, trip, in_body, is_min);
|
|
}
|
|
FALLTHROUGH_INTENDED;
|
|
case HInductionVarAnalysis::kTripCountInBody:
|
|
case HInductionVarAnalysis::kTripCountInBodyUnsafe:
|
|
if (is_min) {
|
|
return Value(0);
|
|
} else if (in_body) {
|
|
return SubValue(GetVal(info->op_a, trip, in_body, is_min), Value(1));
|
|
}
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
break;
|
|
case HInductionVarAnalysis::kLinear:
|
|
return CorrectForType(GetLinear(info, trip, in_body, is_min), info->type);
|
|
case HInductionVarAnalysis::kPolynomial:
|
|
return GetPolynomial(info, trip, in_body, is_min);
|
|
case HInductionVarAnalysis::kGeometric:
|
|
return GetGeometric(info, trip, in_body, is_min);
|
|
case HInductionVarAnalysis::kWrapAround:
|
|
case HInductionVarAnalysis::kPeriodic:
|
|
return MergeVal(GetVal(info->op_a, trip, in_body, is_min),
|
|
GetVal(info->op_b, trip, in_body, is_min), is_min);
|
|
}
|
|
}
|
|
return Value();
|
|
}
|
|
|
|
InductionVarRange::Value InductionVarRange::GetMul(HInductionVarAnalysis::InductionInfo* info1,
|
|
HInductionVarAnalysis::InductionInfo* info2,
|
|
HInductionVarAnalysis::InductionInfo* trip,
|
|
bool in_body,
|
|
bool is_min) const {
|
|
// Constant times range.
|
|
int64_t value = 0;
|
|
if (IsConstant(info1, kExact, &value)) {
|
|
return MulRangeAndConstant(value, info2, trip, in_body, is_min);
|
|
} else if (IsConstant(info2, kExact, &value)) {
|
|
return MulRangeAndConstant(value, info1, trip, in_body, is_min);
|
|
}
|
|
// Interval ranges.
|
|
Value v1_min = GetVal(info1, trip, in_body, /* is_min= */ true);
|
|
Value v1_max = GetVal(info1, trip, in_body, /* is_min= */ false);
|
|
Value v2_min = GetVal(info2, trip, in_body, /* is_min= */ true);
|
|
Value v2_max = GetVal(info2, trip, in_body, /* is_min= */ false);
|
|
// Positive range vs. positive or negative range.
|
|
if (IsConstantValue(v1_min) && v1_min.b_constant >= 0) {
|
|
if (IsConstantValue(v2_min) && v2_min.b_constant >= 0) {
|
|
return is_min ? MulValue(v1_min, v2_min) : MulValue(v1_max, v2_max);
|
|
} else if (IsConstantValue(v2_max) && v2_max.b_constant <= 0) {
|
|
return is_min ? MulValue(v1_max, v2_min) : MulValue(v1_min, v2_max);
|
|
}
|
|
}
|
|
// Negative range vs. positive or negative range.
|
|
if (IsConstantValue(v1_max) && v1_max.b_constant <= 0) {
|
|
if (IsConstantValue(v2_min) && v2_min.b_constant >= 0) {
|
|
return is_min ? MulValue(v1_min, v2_max) : MulValue(v1_max, v2_min);
|
|
} else if (IsConstantValue(v2_max) && v2_max.b_constant <= 0) {
|
|
return is_min ? MulValue(v1_max, v2_max) : MulValue(v1_min, v2_min);
|
|
}
|
|
}
|
|
return Value();
|
|
}
|
|
|
|
InductionVarRange::Value InductionVarRange::GetDiv(HInductionVarAnalysis::InductionInfo* info1,
|
|
HInductionVarAnalysis::InductionInfo* info2,
|
|
HInductionVarAnalysis::InductionInfo* trip,
|
|
bool in_body,
|
|
bool is_min) const {
|
|
// Range divided by constant.
|
|
int64_t value = 0;
|
|
if (IsConstant(info2, kExact, &value)) {
|
|
return DivRangeAndConstant(value, info1, trip, in_body, is_min);
|
|
}
|
|
// Interval ranges.
|
|
Value v1_min = GetVal(info1, trip, in_body, /* is_min= */ true);
|
|
Value v1_max = GetVal(info1, trip, in_body, /* is_min= */ false);
|
|
Value v2_min = GetVal(info2, trip, in_body, /* is_min= */ true);
|
|
Value v2_max = GetVal(info2, trip, in_body, /* is_min= */ false);
|
|
// Positive range vs. positive or negative range.
|
|
if (IsConstantValue(v1_min) && v1_min.b_constant >= 0) {
|
|
if (IsConstantValue(v2_min) && v2_min.b_constant >= 0) {
|
|
return is_min ? DivValue(v1_min, v2_max) : DivValue(v1_max, v2_min);
|
|
} else if (IsConstantValue(v2_max) && v2_max.b_constant <= 0) {
|
|
return is_min ? DivValue(v1_max, v2_max) : DivValue(v1_min, v2_min);
|
|
}
|
|
}
|
|
// Negative range vs. positive or negative range.
|
|
if (IsConstantValue(v1_max) && v1_max.b_constant <= 0) {
|
|
if (IsConstantValue(v2_min) && v2_min.b_constant >= 0) {
|
|
return is_min ? DivValue(v1_min, v2_min) : DivValue(v1_max, v2_max);
|
|
} else if (IsConstantValue(v2_max) && v2_max.b_constant <= 0) {
|
|
return is_min ? DivValue(v1_max, v2_min) : DivValue(v1_min, v2_max);
|
|
}
|
|
}
|
|
return Value();
|
|
}
|
|
|
|
InductionVarRange::Value InductionVarRange::GetRem(
|
|
HInductionVarAnalysis::InductionInfo* info1,
|
|
HInductionVarAnalysis::InductionInfo* info2) const {
|
|
int64_t v1 = 0;
|
|
int64_t v2 = 0;
|
|
// Only accept exact values.
|
|
if (IsConstant(info1, kExact, &v1) && IsConstant(info2, kExact, &v2) && v2 != 0) {
|
|
int64_t value = v1 % v2;
|
|
if (CanLongValueFitIntoInt(value)) {
|
|
return Value(static_cast<int32_t>(value));
|
|
}
|
|
}
|
|
return Value();
|
|
}
|
|
|
|
InductionVarRange::Value InductionVarRange::GetXor(
|
|
HInductionVarAnalysis::InductionInfo* info1,
|
|
HInductionVarAnalysis::InductionInfo* info2) const {
|
|
int64_t v1 = 0;
|
|
int64_t v2 = 0;
|
|
// Only accept exact values.
|
|
if (IsConstant(info1, kExact, &v1) && IsConstant(info2, kExact, &v2)) {
|
|
int64_t value = v1 ^ v2;
|
|
if (CanLongValueFitIntoInt(value)) {
|
|
return Value(static_cast<int32_t>(value));
|
|
}
|
|
}
|
|
return Value();
|
|
}
|
|
|
|
InductionVarRange::Value InductionVarRange::MulRangeAndConstant(
|
|
int64_t value,
|
|
HInductionVarAnalysis::InductionInfo* info,
|
|
HInductionVarAnalysis::InductionInfo* trip,
|
|
bool in_body,
|
|
bool is_min) const {
|
|
if (CanLongValueFitIntoInt(value)) {
|
|
Value c(static_cast<int32_t>(value));
|
|
return MulValue(GetVal(info, trip, in_body, is_min == value >= 0), c);
|
|
}
|
|
return Value();
|
|
}
|
|
|
|
InductionVarRange::Value InductionVarRange::DivRangeAndConstant(
|
|
int64_t value,
|
|
HInductionVarAnalysis::InductionInfo* info,
|
|
HInductionVarAnalysis::InductionInfo* trip,
|
|
bool in_body,
|
|
bool is_min) const {
|
|
if (CanLongValueFitIntoInt(value)) {
|
|
Value c(static_cast<int32_t>(value));
|
|
return DivValue(GetVal(info, trip, in_body, is_min == value >= 0), c);
|
|
}
|
|
return Value();
|
|
}
|
|
|
|
InductionVarRange::Value InductionVarRange::AddValue(Value v1, Value v2) const {
|
|
if (v1.is_known && v2.is_known && IsSafeAdd(v1.b_constant, v2.b_constant)) {
|
|
int32_t b = v1.b_constant + v2.b_constant;
|
|
if (v1.a_constant == 0) {
|
|
return Value(v2.instruction, v2.a_constant, b);
|
|
} else if (v2.a_constant == 0) {
|
|
return Value(v1.instruction, v1.a_constant, b);
|
|
} else if (v1.instruction == v2.instruction && IsSafeAdd(v1.a_constant, v2.a_constant)) {
|
|
return Value(v1.instruction, v1.a_constant + v2.a_constant, b);
|
|
}
|
|
}
|
|
return Value();
|
|
}
|
|
|
|
InductionVarRange::Value InductionVarRange::SubValue(Value v1, Value v2) const {
|
|
if (v1.is_known && v2.is_known && IsSafeSub(v1.b_constant, v2.b_constant)) {
|
|
int32_t b = v1.b_constant - v2.b_constant;
|
|
if (v1.a_constant == 0 && IsSafeSub(0, v2.a_constant)) {
|
|
return Value(v2.instruction, -v2.a_constant, b);
|
|
} else if (v2.a_constant == 0) {
|
|
return Value(v1.instruction, v1.a_constant, b);
|
|
} else if (v1.instruction == v2.instruction && IsSafeSub(v1.a_constant, v2.a_constant)) {
|
|
return Value(v1.instruction, v1.a_constant - v2.a_constant, b);
|
|
}
|
|
}
|
|
return Value();
|
|
}
|
|
|
|
InductionVarRange::Value InductionVarRange::MulValue(Value v1, Value v2) const {
|
|
if (v1.is_known && v2.is_known) {
|
|
if (v1.a_constant == 0) {
|
|
if (IsSafeMul(v1.b_constant, v2.a_constant) && IsSafeMul(v1.b_constant, v2.b_constant)) {
|
|
return Value(v2.instruction, v1.b_constant * v2.a_constant, v1.b_constant * v2.b_constant);
|
|
}
|
|
} else if (v2.a_constant == 0) {
|
|
if (IsSafeMul(v1.a_constant, v2.b_constant) && IsSafeMul(v1.b_constant, v2.b_constant)) {
|
|
return Value(v1.instruction, v1.a_constant * v2.b_constant, v1.b_constant * v2.b_constant);
|
|
}
|
|
}
|
|
}
|
|
return Value();
|
|
}
|
|
|
|
InductionVarRange::Value InductionVarRange::DivValue(Value v1, Value v2) const {
|
|
if (v1.is_known && v2.is_known && v1.a_constant == 0 && v2.a_constant == 0) {
|
|
if (IsSafeDiv(v1.b_constant, v2.b_constant)) {
|
|
return Value(v1.b_constant / v2.b_constant);
|
|
}
|
|
}
|
|
return Value();
|
|
}
|
|
|
|
InductionVarRange::Value InductionVarRange::MergeVal(Value v1, Value v2, bool is_min) const {
|
|
if (v1.is_known && v2.is_known) {
|
|
if (v1.instruction == v2.instruction && v1.a_constant == v2.a_constant) {
|
|
return Value(v1.instruction, v1.a_constant,
|
|
is_min ? std::min(v1.b_constant, v2.b_constant)
|
|
: std::max(v1.b_constant, v2.b_constant));
|
|
}
|
|
}
|
|
return Value();
|
|
}
|
|
|
|
bool InductionVarRange::GenerateRangeOrLastValue(HInstruction* context,
|
|
HInstruction* instruction,
|
|
bool is_last_value,
|
|
HGraph* graph,
|
|
HBasicBlock* block,
|
|
/*out*/HInstruction** lower,
|
|
/*out*/HInstruction** upper,
|
|
/*out*/HInstruction** taken_test,
|
|
/*out*/int64_t* stride_value,
|
|
/*out*/bool* needs_finite_test,
|
|
/*out*/bool* needs_taken_test) const {
|
|
HLoopInformation* loop = nullptr;
|
|
HInductionVarAnalysis::InductionInfo* info = nullptr;
|
|
HInductionVarAnalysis::InductionInfo* trip = nullptr;
|
|
if (!HasInductionInfo(context, instruction, &loop, &info, &trip) || trip == nullptr) {
|
|
return false; // codegen needs all information, including tripcount
|
|
}
|
|
// Determine what tests are needed. A finite test is needed if the evaluation code uses the
|
|
// trip-count and the loop maybe unsafe (because in such cases, the index could "overshoot"
|
|
// the computed range). A taken test is needed for any unknown trip-count, even if evaluation
|
|
// code does not use the trip-count explicitly (since there could be an implicit relation
|
|
// between e.g. an invariant subscript and a not-taken condition).
|
|
bool in_body = context->GetBlock() != loop->GetHeader();
|
|
*stride_value = 0;
|
|
*needs_finite_test = NeedsTripCount(info, stride_value) && IsUnsafeTripCount(trip);
|
|
*needs_taken_test = IsBodyTripCount(trip);
|
|
// Handle last value request.
|
|
if (is_last_value) {
|
|
DCHECK(!in_body);
|
|
switch (info->induction_class) {
|
|
case HInductionVarAnalysis::kLinear:
|
|
if (*stride_value > 0) {
|
|
lower = nullptr;
|
|
} else {
|
|
upper = nullptr;
|
|
}
|
|
break;
|
|
case HInductionVarAnalysis::kPolynomial:
|
|
return GenerateLastValuePolynomial(info, trip, graph, block, lower);
|
|
case HInductionVarAnalysis::kGeometric:
|
|
return GenerateLastValueGeometric(info, trip, graph, block, lower);
|
|
case HInductionVarAnalysis::kWrapAround:
|
|
return GenerateLastValueWrapAround(info, trip, graph, block, lower);
|
|
case HInductionVarAnalysis::kPeriodic:
|
|
return GenerateLastValuePeriodic(info, trip, graph, block, lower, needs_taken_test);
|
|
default:
|
|
return false;
|
|
}
|
|
}
|
|
// Code generation for taken test: generate the code when requested or otherwise analyze
|
|
// if code generation is feasible when taken test is needed.
|
|
if (taken_test != nullptr) {
|
|
return GenerateCode(trip->op_b, nullptr, graph, block, taken_test, in_body, /* is_min= */ false);
|
|
} else if (*needs_taken_test) {
|
|
if (!GenerateCode(
|
|
trip->op_b, nullptr, nullptr, nullptr, nullptr, in_body, /* is_min= */ false)) {
|
|
return false;
|
|
}
|
|
}
|
|
// Code generation for lower and upper.
|
|
return
|
|
// Success on lower if invariant (not set), or code can be generated.
|
|
((info->induction_class == HInductionVarAnalysis::kInvariant) ||
|
|
GenerateCode(info, trip, graph, block, lower, in_body, /* is_min= */ true)) &&
|
|
// And success on upper.
|
|
GenerateCode(info, trip, graph, block, upper, in_body, /* is_min= */ false);
|
|
}
|
|
|
|
bool InductionVarRange::GenerateLastValuePolynomial(HInductionVarAnalysis::InductionInfo* info,
|
|
HInductionVarAnalysis::InductionInfo* trip,
|
|
HGraph* graph,
|
|
HBasicBlock* block,
|
|
/*out*/HInstruction** result) const {
|
|
DCHECK(info != nullptr);
|
|
DCHECK_EQ(info->induction_class, HInductionVarAnalysis::kPolynomial);
|
|
// Detect known coefficients and trip count (always taken).
|
|
int64_t a = 0;
|
|
int64_t b = 0;
|
|
int64_t m = 0;
|
|
if (IsConstant(info->op_a->op_a, kExact, &a) &&
|
|
IsConstant(info->op_a->op_b, kExact, &b) &&
|
|
IsConstant(trip->op_a, kExact, &m) && m >= 1) {
|
|
// Evaluate bounds on sum_i=0^m-1(a * i + b) + c for known
|
|
// maximum index value m as a * (m * (m-1)) / 2 + b * m + c.
|
|
HInstruction* c = nullptr;
|
|
if (GenerateCode(info->op_b, nullptr, graph, block, graph ? &c : nullptr, false, false)) {
|
|
if (graph != nullptr) {
|
|
DataType::Type type = info->type;
|
|
int64_t sum = a * ((m * (m - 1)) / 2) + b * m;
|
|
if (type != DataType::Type::kInt64) {
|
|
sum = static_cast<int32_t>(sum); // okay to truncate
|
|
}
|
|
*result =
|
|
Insert(block, new (graph->GetAllocator()) HAdd(type, graph->GetConstant(type, sum), c));
|
|
}
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
bool InductionVarRange::GenerateLastValueGeometric(HInductionVarAnalysis::InductionInfo* info,
|
|
HInductionVarAnalysis::InductionInfo* trip,
|
|
HGraph* graph,
|
|
HBasicBlock* block,
|
|
/*out*/HInstruction** result) const {
|
|
DCHECK(info != nullptr);
|
|
DCHECK_EQ(info->induction_class, HInductionVarAnalysis::kGeometric);
|
|
// Detect known base and trip count (always taken).
|
|
int64_t f = 0;
|
|
int64_t m = 0;
|
|
if (IsInt64AndGet(info->fetch, &f) && f >= 1 && IsConstant(trip->op_a, kExact, &m) && m >= 1) {
|
|
HInstruction* opa = nullptr;
|
|
HInstruction* opb = nullptr;
|
|
if (GenerateCode(info->op_a, nullptr, graph, block, &opa, false, false) &&
|
|
GenerateCode(info->op_b, nullptr, graph, block, &opb, false, false)) {
|
|
if (graph != nullptr) {
|
|
DataType::Type type = info->type;
|
|
// Compute f ^ m for known maximum index value m.
|
|
bool overflow = false;
|
|
int64_t fpow = IntPow(f, m, &overflow);
|
|
if (info->operation == HInductionVarAnalysis::kDiv) {
|
|
// For division, any overflow truncates to zero.
|
|
if (overflow || (type != DataType::Type::kInt64 && !CanLongValueFitIntoInt(fpow))) {
|
|
fpow = 0;
|
|
}
|
|
} else if (type != DataType::Type::kInt64) {
|
|
// For multiplication, okay to truncate to required precision.
|
|
DCHECK(info->operation == HInductionVarAnalysis::kMul);
|
|
fpow = static_cast<int32_t>(fpow);
|
|
}
|
|
// Generate code.
|
|
if (fpow == 0) {
|
|
// Special case: repeated mul/div always yields zero.
|
|
*result = graph->GetConstant(type, 0);
|
|
} else {
|
|
// Last value: a * f ^ m + b or a * f ^ -m + b.
|
|
HInstruction* e = nullptr;
|
|
ArenaAllocator* allocator = graph->GetAllocator();
|
|
if (info->operation == HInductionVarAnalysis::kMul) {
|
|
e = new (allocator) HMul(type, opa, graph->GetConstant(type, fpow));
|
|
} else {
|
|
e = new (allocator) HDiv(type, opa, graph->GetConstant(type, fpow), kNoDexPc);
|
|
}
|
|
*result = Insert(block, new (allocator) HAdd(type, Insert(block, e), opb));
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
bool InductionVarRange::GenerateLastValueWrapAround(HInductionVarAnalysis::InductionInfo* info,
|
|
HInductionVarAnalysis::InductionInfo* trip,
|
|
HGraph* graph,
|
|
HBasicBlock* block,
|
|
/*out*/HInstruction** result) const {
|
|
DCHECK(info != nullptr);
|
|
DCHECK_EQ(info->induction_class, HInductionVarAnalysis::kWrapAround);
|
|
// Count depth.
|
|
int32_t depth = 0;
|
|
for (; info->induction_class == HInductionVarAnalysis::kWrapAround;
|
|
info = info->op_b, ++depth) {}
|
|
// Handle wrap(x, wrap(.., y)) if trip count reaches an invariant at end.
|
|
// TODO: generalize, but be careful to adjust the terminal.
|
|
int64_t m = 0;
|
|
if (info->induction_class == HInductionVarAnalysis::kInvariant &&
|
|
IsConstant(trip->op_a, kExact, &m) && m >= depth) {
|
|
return GenerateCode(info, nullptr, graph, block, result, false, false);
|
|
}
|
|
return false;
|
|
}
|
|
|
|
bool InductionVarRange::GenerateLastValuePeriodic(HInductionVarAnalysis::InductionInfo* info,
|
|
HInductionVarAnalysis::InductionInfo* trip,
|
|
HGraph* graph,
|
|
HBasicBlock* block,
|
|
/*out*/HInstruction** result,
|
|
/*out*/bool* needs_taken_test) const {
|
|
DCHECK(info != nullptr);
|
|
DCHECK_EQ(info->induction_class, HInductionVarAnalysis::kPeriodic);
|
|
// Count period and detect all-invariants.
|
|
int64_t period = 1;
|
|
bool all_invariants = true;
|
|
HInductionVarAnalysis::InductionInfo* p = info;
|
|
for (; p->induction_class == HInductionVarAnalysis::kPeriodic; p = p->op_b, ++period) {
|
|
DCHECK_EQ(p->op_a->induction_class, HInductionVarAnalysis::kInvariant);
|
|
if (p->op_a->operation != HInductionVarAnalysis::kFetch) {
|
|
all_invariants = false;
|
|
}
|
|
}
|
|
DCHECK_EQ(p->induction_class, HInductionVarAnalysis::kInvariant);
|
|
if (p->operation != HInductionVarAnalysis::kFetch) {
|
|
all_invariants = false;
|
|
}
|
|
// Don't rely on FP arithmetic to be precise, unless the full period
|
|
// consist of pre-computed expressions only.
|
|
if (info->type == DataType::Type::kFloat32 || info->type == DataType::Type::kFloat64) {
|
|
if (!all_invariants) {
|
|
return false;
|
|
}
|
|
}
|
|
// Handle any periodic(x, periodic(.., y)) for known maximum index value m.
|
|
int64_t m = 0;
|
|
if (IsConstant(trip->op_a, kExact, &m) && m >= 1) {
|
|
int64_t li = m % period;
|
|
for (int64_t i = 0; i < li; info = info->op_b, i++) {}
|
|
if (info->induction_class == HInductionVarAnalysis::kPeriodic) {
|
|
info = info->op_a;
|
|
}
|
|
return GenerateCode(info, nullptr, graph, block, result, false, false);
|
|
}
|
|
// Handle periodic(x, y) using even/odd-select on trip count. Enter trip count expression
|
|
// directly to obtain the maximum index value t even if taken test is needed.
|
|
HInstruction* x = nullptr;
|
|
HInstruction* y = nullptr;
|
|
HInstruction* t = nullptr;
|
|
if (period == 2 &&
|
|
GenerateCode(info->op_a, nullptr, graph, block, graph ? &x : nullptr, false, false) &&
|
|
GenerateCode(info->op_b, nullptr, graph, block, graph ? &y : nullptr, false, false) &&
|
|
GenerateCode(trip->op_a, nullptr, graph, block, graph ? &t : nullptr, false, false)) {
|
|
// During actual code generation (graph != nullptr), generate is_even ? x : y.
|
|
if (graph != nullptr) {
|
|
DataType::Type type = trip->type;
|
|
ArenaAllocator* allocator = graph->GetAllocator();
|
|
HInstruction* msk =
|
|
Insert(block, new (allocator) HAnd(type, t, graph->GetConstant(type, 1)));
|
|
HInstruction* is_even =
|
|
Insert(block, new (allocator) HEqual(msk, graph->GetConstant(type, 0), kNoDexPc));
|
|
*result = Insert(block, new (graph->GetAllocator()) HSelect(is_even, x, y, kNoDexPc));
|
|
}
|
|
// Guard select with taken test if needed.
|
|
if (*needs_taken_test) {
|
|
HInstruction* is_taken = nullptr;
|
|
if (GenerateCode(trip->op_b, nullptr, graph, block, graph ? &is_taken : nullptr, false, false)) {
|
|
if (graph != nullptr) {
|
|
ArenaAllocator* allocator = graph->GetAllocator();
|
|
*result = Insert(block, new (allocator) HSelect(is_taken, *result, x, kNoDexPc));
|
|
}
|
|
*needs_taken_test = false; // taken care of
|
|
} else {
|
|
return false;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
bool InductionVarRange::GenerateCode(HInductionVarAnalysis::InductionInfo* info,
|
|
HInductionVarAnalysis::InductionInfo* trip,
|
|
HGraph* graph, // when set, code is generated
|
|
HBasicBlock* block,
|
|
/*out*/HInstruction** result,
|
|
bool in_body,
|
|
bool is_min) const {
|
|
if (info != nullptr) {
|
|
// If during codegen, the result is not needed (nullptr), simply return success.
|
|
if (graph != nullptr && result == nullptr) {
|
|
return true;
|
|
}
|
|
// Handle current operation.
|
|
DataType::Type type = info->type;
|
|
HInstruction* opa = nullptr;
|
|
HInstruction* opb = nullptr;
|
|
switch (info->induction_class) {
|
|
case HInductionVarAnalysis::kInvariant:
|
|
// Invariants (note that since invariants only have other invariants as
|
|
// sub expressions, viz. no induction, there is no need to adjust is_min).
|
|
switch (info->operation) {
|
|
case HInductionVarAnalysis::kAdd:
|
|
case HInductionVarAnalysis::kSub:
|
|
case HInductionVarAnalysis::kMul:
|
|
case HInductionVarAnalysis::kDiv:
|
|
case HInductionVarAnalysis::kRem:
|
|
case HInductionVarAnalysis::kXor:
|
|
case HInductionVarAnalysis::kLT:
|
|
case HInductionVarAnalysis::kLE:
|
|
case HInductionVarAnalysis::kGT:
|
|
case HInductionVarAnalysis::kGE:
|
|
if (GenerateCode(info->op_a, trip, graph, block, &opa, in_body, is_min) &&
|
|
GenerateCode(info->op_b, trip, graph, block, &opb, in_body, is_min)) {
|
|
if (graph != nullptr) {
|
|
HInstruction* operation = nullptr;
|
|
switch (info->operation) {
|
|
case HInductionVarAnalysis::kAdd:
|
|
operation = new (graph->GetAllocator()) HAdd(type, opa, opb); break;
|
|
case HInductionVarAnalysis::kSub:
|
|
operation = new (graph->GetAllocator()) HSub(type, opa, opb); break;
|
|
case HInductionVarAnalysis::kMul:
|
|
operation = new (graph->GetAllocator()) HMul(type, opa, opb, kNoDexPc); break;
|
|
case HInductionVarAnalysis::kDiv:
|
|
operation = new (graph->GetAllocator()) HDiv(type, opa, opb, kNoDexPc); break;
|
|
case HInductionVarAnalysis::kRem:
|
|
operation = new (graph->GetAllocator()) HRem(type, opa, opb, kNoDexPc); break;
|
|
case HInductionVarAnalysis::kXor:
|
|
operation = new (graph->GetAllocator()) HXor(type, opa, opb); break;
|
|
case HInductionVarAnalysis::kLT:
|
|
operation = new (graph->GetAllocator()) HLessThan(opa, opb); break;
|
|
case HInductionVarAnalysis::kLE:
|
|
operation = new (graph->GetAllocator()) HLessThanOrEqual(opa, opb); break;
|
|
case HInductionVarAnalysis::kGT:
|
|
operation = new (graph->GetAllocator()) HGreaterThan(opa, opb); break;
|
|
case HInductionVarAnalysis::kGE:
|
|
operation = new (graph->GetAllocator()) HGreaterThanOrEqual(opa, opb); break;
|
|
default:
|
|
LOG(FATAL) << "unknown operation";
|
|
}
|
|
*result = Insert(block, operation);
|
|
}
|
|
return true;
|
|
}
|
|
break;
|
|
case HInductionVarAnalysis::kNeg:
|
|
if (GenerateCode(info->op_b, trip, graph, block, &opb, in_body, !is_min)) {
|
|
if (graph != nullptr) {
|
|
*result = Insert(block, new (graph->GetAllocator()) HNeg(type, opb));
|
|
}
|
|
return true;
|
|
}
|
|
break;
|
|
case HInductionVarAnalysis::kFetch:
|
|
if (graph != nullptr) {
|
|
*result = info->fetch; // already in HIR
|
|
}
|
|
return true;
|
|
case HInductionVarAnalysis::kTripCountInLoop:
|
|
case HInductionVarAnalysis::kTripCountInLoopUnsafe:
|
|
if (!in_body && !is_min) { // one extra!
|
|
return GenerateCode(info->op_a, trip, graph, block, result, in_body, is_min);
|
|
}
|
|
FALLTHROUGH_INTENDED;
|
|
case HInductionVarAnalysis::kTripCountInBody:
|
|
case HInductionVarAnalysis::kTripCountInBodyUnsafe:
|
|
if (is_min) {
|
|
if (graph != nullptr) {
|
|
*result = graph->GetConstant(type, 0);
|
|
}
|
|
return true;
|
|
} else if (in_body) {
|
|
if (GenerateCode(info->op_a, trip, graph, block, &opb, in_body, is_min)) {
|
|
if (graph != nullptr) {
|
|
ArenaAllocator* allocator = graph->GetAllocator();
|
|
*result =
|
|
Insert(block, new (allocator) HSub(type, opb, graph->GetConstant(type, 1)));
|
|
}
|
|
return true;
|
|
}
|
|
}
|
|
break;
|
|
case HInductionVarAnalysis::kNop:
|
|
LOG(FATAL) << "unexpected invariant nop";
|
|
} // switch invariant operation
|
|
break;
|
|
case HInductionVarAnalysis::kLinear: {
|
|
// Linear induction a * i + b, for normalized 0 <= i < TC. For ranges, this should
|
|
// be restricted to a unit stride to avoid arithmetic wrap-around situations that
|
|
// are harder to guard against. For a last value, requesting min/max based on any
|
|
// known stride yields right value. Always avoid any narrowing linear induction or
|
|
// any type mismatch between the linear induction and the trip count expression.
|
|
// TODO: careful runtime type conversions could generalize this latter restriction.
|
|
if (!HInductionVarAnalysis::IsNarrowingLinear(info) && trip->type == type) {
|
|
int64_t stride_value = 0;
|
|
if (IsConstant(info->op_a, kExact, &stride_value) &&
|
|
CanLongValueFitIntoInt(stride_value)) {
|
|
const bool is_min_a = stride_value >= 0 ? is_min : !is_min;
|
|
if (GenerateCode(trip, trip, graph, block, &opa, in_body, is_min_a) &&
|
|
GenerateCode(info->op_b, trip, graph, block, &opb, in_body, is_min)) {
|
|
if (graph != nullptr) {
|
|
ArenaAllocator* allocator = graph->GetAllocator();
|
|
HInstruction* oper;
|
|
if (stride_value == 1) {
|
|
oper = new (allocator) HAdd(type, opa, opb);
|
|
} else if (stride_value == -1) {
|
|
oper = new (graph->GetAllocator()) HSub(type, opb, opa);
|
|
} else {
|
|
HInstruction* mul =
|
|
new (allocator) HMul(type, graph->GetConstant(type, stride_value), opa);
|
|
oper = new (allocator) HAdd(type, Insert(block, mul), opb);
|
|
}
|
|
*result = Insert(block, oper);
|
|
}
|
|
return true;
|
|
}
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
case HInductionVarAnalysis::kPolynomial:
|
|
case HInductionVarAnalysis::kGeometric:
|
|
break;
|
|
case HInductionVarAnalysis::kWrapAround:
|
|
case HInductionVarAnalysis::kPeriodic: {
|
|
// Wrap-around and periodic inductions are restricted to constants only, so that extreme
|
|
// values are easy to test at runtime without complications of arithmetic wrap-around.
|
|
Value extreme = GetVal(info, trip, in_body, is_min);
|
|
if (IsConstantValue(extreme)) {
|
|
if (graph != nullptr) {
|
|
*result = graph->GetConstant(type, extreme.b_constant);
|
|
}
|
|
return true;
|
|
}
|
|
break;
|
|
}
|
|
} // switch induction class
|
|
}
|
|
return false;
|
|
}
|
|
|
|
void InductionVarRange::ReplaceInduction(HInductionVarAnalysis::InductionInfo* info,
|
|
HInstruction* fetch,
|
|
HInstruction* replacement) {
|
|
if (info != nullptr) {
|
|
if (info->induction_class == HInductionVarAnalysis::kInvariant &&
|
|
info->operation == HInductionVarAnalysis::kFetch &&
|
|
info->fetch == fetch) {
|
|
info->fetch = replacement;
|
|
}
|
|
ReplaceInduction(info->op_a, fetch, replacement);
|
|
ReplaceInduction(info->op_b, fetch, replacement);
|
|
}
|
|
}
|
|
|
|
} // namespace art
|