From: Aart Bik Date: Thu, 23 Jun 2016 18:20:41 +0000 (-0700) Subject: Improvements in induction range analysis. X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=52be7e759acecc3841dca0ac1b703034d8cad60d;p=android-x86%2Fart.git Improvements in induction range analysis. Rationale: Uses range analysis while determining whether trip-counts are "safe", which improves analysis of triangular loops. Also implements more effective triangular loop analysis by evaluating induction information only once and using a top level hint (instead of the "iterative refinement" that was used earlier). Also fixes analysis of triangular trip counts that may wrap-around. All with tests. Test: see induction_var_range_test/530-checker-loops* BUG=27151190 Change-Id: I1877c8ce0c9a52005900eb9dfdbb1918df100278 --- diff --git a/compiler/optimizing/bounds_check_elimination.cc b/compiler/optimizing/bounds_check_elimination.cc index e9fcfe2be..d786e82d1 100644 --- a/compiler/optimizing/bounds_check_elimination.cc +++ b/compiler/optimizing/bounds_check_elimination.cc @@ -847,7 +847,7 @@ class BCEVisitor : public HGraphVisitor { } // Try index range obtained by induction variable analysis. // Disables dynamic bce if OOB is certain. - if (InductionRangeFitsIn(&array_range, bounds_check, index, &try_dynamic_bce)) { + if (InductionRangeFitsIn(&array_range, bounds_check, &try_dynamic_bce)) { ReplaceInstruction(bounds_check, index); return; } @@ -1299,33 +1299,30 @@ class BCEVisitor : public HGraphVisitor { * parameter try_dynamic_bce is set to false if OOB is certain. */ bool InductionRangeFitsIn(ValueRange* array_range, - HInstruction* context, - HInstruction* index, + HBoundsCheck* context, bool* try_dynamic_bce) { InductionVarRange::Value v1; InductionVarRange::Value v2; bool needs_finite_test = false; - if (induction_range_.GetInductionRange(context, index, &v1, &v2, &needs_finite_test)) { - do { - if (v1.is_known && (v1.a_constant == 0 || v1.a_constant == 1) && - v2.is_known && (v2.a_constant == 0 || v2.a_constant == 1)) { - DCHECK(v1.a_constant == 1 || v1.instruction == nullptr); - DCHECK(v2.a_constant == 1 || v2.instruction == nullptr); - ValueRange index_range(GetGraph()->GetArena(), - ValueBound(v1.instruction, v1.b_constant), - ValueBound(v2.instruction, v2.b_constant)); - // If analysis reveals a certain OOB, disable dynamic BCE. - if (index_range.GetLower().LessThan(array_range->GetLower()) || - index_range.GetUpper().GreaterThan(array_range->GetUpper())) { - *try_dynamic_bce = false; - return false; - } - // Use analysis for static bce only if loop is finite. - if (!needs_finite_test && index_range.FitsIn(array_range)) { - return true; - } + HInstruction* index = context->InputAt(0); + HInstruction* hint = ValueBound::HuntForDeclaration(context->InputAt(1)); + if (induction_range_.GetInductionRange(context, index, hint, &v1, &v2, &needs_finite_test)) { + if (v1.is_known && (v1.a_constant == 0 || v1.a_constant == 1) && + v2.is_known && (v2.a_constant == 0 || v2.a_constant == 1)) { + DCHECK(v1.a_constant == 1 || v1.instruction == nullptr); + DCHECK(v2.a_constant == 1 || v2.instruction == nullptr); + ValueRange index_range(GetGraph()->GetArena(), + ValueBound(v1.instruction, v1.b_constant), + ValueBound(v2.instruction, v2.b_constant)); + // If analysis reveals a certain OOB, disable dynamic BCE. Otherwise, + // use analysis for static bce only if loop is finite. + if (index_range.GetLower().LessThan(array_range->GetLower()) || + index_range.GetUpper().GreaterThan(array_range->GetUpper())) { + *try_dynamic_bce = false; + } else if (!needs_finite_test && index_range.FitsIn(array_range)) { + return true; } - } while (induction_range_.RefineOuter(&v1, &v2)); + } } return false; } diff --git a/compiler/optimizing/induction_var_analysis.h b/compiler/optimizing/induction_var_analysis.h index f1965f07b..7c74816c2 100644 --- a/compiler/optimizing/induction_var_analysis.h +++ b/compiler/optimizing/induction_var_analysis.h @@ -132,7 +132,7 @@ class HInductionVarAnalysis : public HOptimization { InductionInfo* a, InductionInfo* b, Primitive::Type type) { - DCHECK(a != nullptr); + DCHECK(a != nullptr && b != nullptr); return new (graph_->GetArena()) InductionInfo(kInvariant, op, a, b, nullptr, type); } diff --git a/compiler/optimizing/induction_var_range.cc b/compiler/optimizing/induction_var_range.cc index bc920d96b..5e587e081 100644 --- a/compiler/optimizing/induction_var_range.cc +++ b/compiler/optimizing/induction_var_range.cc @@ -73,9 +73,12 @@ static InductionVarRange::Value SimplifyMax(InductionVarRange::Value v) { return v; } -/** - * Corrects a value for type to account for arithmetic wrap-around in lower precision. - */ +/** Helper method to test for a constant value. */ +static bool IsConstantValue(InductionVarRange::Value v) { + return v.is_known && v.a_constant == 0; +} + +/** Corrects a value for type to account for arithmetic wrap-around in lower precision. */ static InductionVarRange::Value CorrectForType(InductionVarRange::Value v, Primitive::Type type) { switch (type) { case Primitive::kPrimShort: @@ -85,26 +88,15 @@ static InductionVarRange::Value CorrectForType(InductionVarRange::Value v, Primi // TODO: maybe some room for improvement, like allowing widening conversions const int32_t min = Primitive::MinValueOfIntegralType(type); const int32_t max = Primitive::MaxValueOfIntegralType(type); - return (v.is_known && v.a_constant == 0 && min <= v.b_constant && v.b_constant <= max) + return (IsConstantValue(v) && min <= v.b_constant && v.b_constant <= max) ? v : InductionVarRange::Value(); } default: - // At int or higher. return v; } } -/** Helper method to test for a constant value. */ -static bool IsConstantValue(InductionVarRange::Value v) { - return v.is_known && v.a_constant == 0; -} - -/** Helper method to test for same constant value. */ -static bool IsSameConstantValue(InductionVarRange::Value v1, InductionVarRange::Value v2) { - return IsConstantValue(v1) && IsConstantValue(v2) && v1.b_constant == v2.b_constant; -} - /** Helper method to insert an instruction. */ static HInstruction* Insert(HBasicBlock* block, HInstruction* instruction) { DCHECK(block != nullptr); @@ -119,22 +111,22 @@ static HInstruction* Insert(HBasicBlock* block, HInstruction* instruction) { // InductionVarRange::InductionVarRange(HInductionVarAnalysis* induction_analysis) - : induction_analysis_(induction_analysis) { + : induction_analysis_(induction_analysis), + chase_hint_(nullptr) { DCHECK(induction_analysis != nullptr); } bool InductionVarRange::GetInductionRange(HInstruction* context, HInstruction* instruction, + HInstruction* chase_hint, /*out*/Value* min_val, /*out*/Value* max_val, /*out*/bool* needs_finite_test) { - HLoopInformation* loop = context->GetBlock()->GetLoopInformation(); // closest enveloping loop - if (loop == nullptr) { - return false; // no loop - } - HInductionVarAnalysis::InductionInfo* info = induction_analysis_->LookupInfo(loop, instruction); - if (info == nullptr) { - return false; // no induction information + HLoopInformation* loop = nullptr; + HInductionVarAnalysis::InductionInfo* info = nullptr; + HInductionVarAnalysis::InductionInfo* trip = nullptr; + if (!HasInductionInfo(context, instruction, &loop, &info, &trip)) { + return false; } // Type int or lower (this is not too restrictive since intended clients, like // bounds check elimination, will have truncated higher precision induction @@ -148,45 +140,15 @@ bool InductionVarRange::GetInductionRange(HInstruction* context, default: return false; } - // Set up loop information. - HBasicBlock* header = loop->GetHeader(); - bool in_body = context->GetBlock() != header; - HInductionVarAnalysis::InductionInfo* trip = - induction_analysis_->LookupInfo(loop, header->GetLastInstruction()); // Find range. + chase_hint_ = chase_hint; + bool in_body = context->GetBlock() != loop->GetHeader(); *min_val = GetVal(info, trip, in_body, /* is_min */ true); *max_val = SimplifyMax(GetVal(info, trip, in_body, /* is_min */ false)); *needs_finite_test = NeedsTripCount(info) && IsUnsafeTripCount(trip); return true; } -bool InductionVarRange::RefineOuter(/*in-out*/ Value* min_val, - /*in-out*/ Value* max_val) const { - if (min_val->instruction != nullptr || max_val->instruction != nullptr) { - Value v1_min = RefineOuter(*min_val, /* is_min */ true); - Value v2_max = RefineOuter(*max_val, /* is_min */ false); - // The refined range is safe if both sides refine the same instruction. Otherwise, since two - // different ranges are combined, the new refined range is safe to pass back to the client if - // the extremes of the computed ranges ensure no arithmetic wrap-around anomalies occur. - if (min_val->instruction != max_val->instruction) { - Value v1_max = RefineOuter(*min_val, /* is_min */ false); - Value v2_min = RefineOuter(*max_val, /* is_min */ true); - if (!IsConstantValue(v1_max) || - !IsConstantValue(v2_min) || - v1_max.b_constant > v2_min.b_constant) { - return false; - } - } - // Did something change? - if (v1_min.instruction != min_val->instruction || v2_max.instruction != max_val->instruction) { - *min_val = v1_min; - *max_val = v2_max; - return true; - } - } - return false; -} - bool InductionVarRange::CanGenerateCode(HInstruction* context, HInstruction* instruction, /*out*/bool* needs_finite_test, @@ -226,7 +188,7 @@ void InductionVarRange::GenerateTakenTest(HInstruction* context, bool InductionVarRange::IsConstant(HInductionVarAnalysis::InductionInfo* info, ConstantRequest request, - /*out*/ int64_t *value) const { + /*out*/ int64_t* value) const { if (info != nullptr) { // A direct 32-bit or 64-bit constant fetch. This immediately satisfies // any of the three requests (kExact, kAtMost, and KAtLeast). @@ -236,27 +198,16 @@ bool InductionVarRange::IsConstant(HInductionVarAnalysis::InductionInfo* info, return true; } } - // Try range analysis while traversing outward on loops. - bool in_body = true; // no known trip count - Value v_min = GetVal(info, nullptr, in_body, /* is_min */ true); - Value v_max = GetVal(info, nullptr, in_body, /* is_min */ false); - do { - // Make sure *both* extremes are known to avoid arithmetic wrap-around anomalies. - if (IsConstantValue(v_min) && IsConstantValue(v_max) && v_min.b_constant <= v_max.b_constant) { - if ((request == kExact && v_min.b_constant == v_max.b_constant) || request == kAtMost) { - *value = v_max.b_constant; - return true; - } else if (request == kAtLeast) { - *value = v_min.b_constant; - return true; - } - } - } while (RefineOuter(&v_min, &v_max)); - // Exploit array length + c >= c, with c <= 0 to avoid arithmetic wrap-around anomalies - // (e.g. array length == maxint and c == 1 would yield minint). - if (request == kAtLeast) { - if (v_min.a_constant == 1 && v_min.b_constant <= 0 && v_min.instruction->IsArrayLength()) { - *value = v_min.b_constant; + // Try range analysis on the invariant, but only on proper range to avoid wrap-around anomalies. + Value min_val = GetVal(info, nullptr, /* in_body */ true, /* is_min */ true); + Value max_val = GetVal(info, nullptr, /* in_body */ true, /* is_min */ false); + if (IsConstantValue(min_val) && + IsConstantValue(max_val) && min_val.b_constant <= max_val.b_constant) { + if ((request == kExact && min_val.b_constant == max_val.b_constant) || request == kAtMost) { + *value = max_val.b_constant; + return true; + } else if (request == kAtLeast) { + *value = min_val.b_constant; return true; } } @@ -264,6 +215,51 @@ bool InductionVarRange::IsConstant(HInductionVarAnalysis::InductionInfo* info, return false; } +bool InductionVarRange::HasInductionInfo( + HInstruction* context, + HInstruction* instruction, + /*out*/ HLoopInformation** loop, + /*out*/ HInductionVarAnalysis::InductionInfo** info, + /*out*/ HInductionVarAnalysis::InductionInfo** trip) const { + HLoopInformation* l = context->GetBlock()->GetLoopInformation(); // closest enveloping loop + if (l != nullptr) { + HInductionVarAnalysis::InductionInfo* i = induction_analysis_->LookupInfo(l, instruction); + if (i != nullptr) { + *loop = l; + *info = i; + *trip = induction_analysis_->LookupInfo(l, l->GetHeader()->GetLastInstruction()); + return true; + } + } + return false; +} + +bool InductionVarRange::IsWellBehavedTripCount(HInductionVarAnalysis::InductionInfo* trip) const { + if (trip != nullptr) { + // Both bounds that define a trip-count are well-behaved if they either are not defined + // in any loop, or are contained in a proper interval. This allows finding the min/max + // of an expression by chasing outward. + InductionVarRange range(induction_analysis_); + HInductionVarAnalysis::InductionInfo* lower = trip->op_b->op_a; + HInductionVarAnalysis::InductionInfo* upper = trip->op_b->op_b; + int64_t not_used = 0; + return (!HasFetchInLoop(lower) || range.IsConstant(lower, kAtLeast, ¬_used)) && + (!HasFetchInLoop(upper) || range.IsConstant(upper, kAtLeast, ¬_used)); + } + return true; +} + +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) const { if (info != nullptr) { if (info->induction_class == HInductionVarAnalysis::kLinear) { @@ -299,13 +295,13 @@ InductionVarRange::Value InductionVarRange::GetLinear(HInductionVarAnalysis::Ind HInductionVarAnalysis::InductionInfo* trip, bool in_body, bool is_min) const { - // Detect common situation where an offset inside the trip count cancels out during range + // 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->operation == HInductionVarAnalysis::kSub) { + 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) { @@ -349,12 +345,25 @@ InductionVarRange::Value InductionVarRange::GetFetch(HInstruction* instruction, HInductionVarAnalysis::InductionInfo* trip, bool in_body, bool is_min) const { - // Detect constants and chase the fetch a bit deeper into the HIR tree, so that it becomes - // more likely range analysis will compare the same instructions as terminal nodes. + // Stop chasing the instruction at constant or hint. int64_t value; - if (IsIntAndGet(instruction, &value) && CanLongValueFitIntoInt(value)) { + if (IsIntAndGet(instruction, &value) && CanLongValueFitIntoInt(value)) { return Value(static_cast(value)); - } else if (instruction->IsAdd()) { + } else if (instruction == chase_hint_) { + return Value(instruction, 1, 0); + } + // Special cases when encountering a single instruction that denotes trip count in the + // loop-body: min is 1 and, when chasing constants, max of safe trip-count is max int + if (in_body && trip != nullptr && instruction == trip->op_a->fetch) { + if (is_min) { + return Value(1); + } else if (chase_hint_ == nullptr && !IsUnsafeTripCount(trip)) { + return Value(std::numeric_limits::max()); + } + } + // 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. + if (instruction->IsAdd()) { if (IsIntAndGet(instruction->InputAt(0), &value) && CanLongValueFitIntoInt(value)) { return AddValue(Value(static_cast(value)), GetFetch(instruction->InputAt(1), trip, in_body, is_min)); @@ -362,19 +371,35 @@ InductionVarRange::Value InductionVarRange::GetFetch(HInstruction* instruction, return AddValue(GetFetch(instruction->InputAt(0), trip, in_body, is_min), Value(static_cast(value))); } - } else if (instruction->IsArrayLength() && instruction->InputAt(0)->IsNewArray()) { - return GetFetch(instruction->InputAt(0)->InputAt(0), trip, in_body, is_min); + } else if (instruction->IsArrayLength()) { + // Return extreme values when chasing constants. Otherwise, chase deeper. + if (chase_hint_ == nullptr) { + return is_min ? Value(0) : Value(std::numeric_limits::max()); + } else if (instruction->InputAt(0)->IsNewArray()) { + return GetFetch(instruction->InputAt(0)->InputAt(0), trip, in_body, is_min); + } } else if (instruction->IsTypeConversion()) { // Since analysis is 32-bit (or narrower) we allow a widening along the path. if (instruction->AsTypeConversion()->GetInputType() == Primitive::kPrimInt && instruction->AsTypeConversion()->GetResultType() == Primitive::kPrimLong) { return GetFetch(instruction->InputAt(0), trip, in_body, is_min); } - } else if (is_min) { - // Special case for finding minimum: minimum of trip-count in loop-body is 1. - if (trip != nullptr && in_body && instruction == trip->op_a->fetch) { - return Value(1); - } + } + // 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); } return Value(instruction, 1, 0); } @@ -421,9 +446,8 @@ InductionVarRange::Value InductionVarRange::GetVal(HInductionVarAnalysis::Induct break; } break; - case HInductionVarAnalysis::kLinear: { + case HInductionVarAnalysis::kLinear: return CorrectForType(GetLinear(info, trip, in_body, is_min), info->type); - } case HInductionVarAnalysis::kWrapAround: case HInductionVarAnalysis::kPeriodic: return MergeVal(GetVal(info->op_a, trip, in_body, is_min), @@ -438,20 +462,18 @@ InductionVarRange::Value InductionVarRange::GetMul(HInductionVarAnalysis::Induct 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); - // Try to refine first operand. - if (!IsConstantValue(v1_min) && !IsConstantValue(v1_max)) { - RefineOuter(&v1_min, &v1_max); - } - // Constant times range. - if (IsSameConstantValue(v1_min, v1_max)) { - return MulRangeAndConstant(v2_min, v2_max, v1_min, is_min); - } else if (IsSameConstantValue(v2_min, v2_max)) { - return MulRangeAndConstant(v1_min, v1_max, v2_min, is_min); - } // 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) { @@ -476,14 +498,16 @@ InductionVarRange::Value InductionVarRange::GetDiv(HInductionVarAnalysis::Induct 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); - // Range divided by constant. - if (IsSameConstantValue(v2_min, v2_max)) { - return DivRangeAndConstant(v1_min, v1_max, v2_min, is_min); - } // 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) { @@ -503,18 +527,30 @@ InductionVarRange::Value InductionVarRange::GetDiv(HInductionVarAnalysis::Induct return Value(); } -InductionVarRange::Value InductionVarRange::MulRangeAndConstant(Value v_min, - Value v_max, - Value c, - bool is_min) const { - return is_min == (c.b_constant >= 0) ? MulValue(v_min, c) : MulValue(v_max, c); +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(value)); + return MulValue(GetVal(info, trip, in_body, is_min == value >= 0), c); + } + return Value(); } -InductionVarRange::Value InductionVarRange::DivRangeAndConstant(Value v_min, - Value v_max, - Value c, - bool is_min) const { - return is_min == (c.b_constant >= 0) ? DivValue(v_min, c) : DivValue(v_max, c); +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(value)); + return DivValue(GetVal(info, trip, in_body, is_min == value >= 0), c); + } + return Value(); } InductionVarRange::Value InductionVarRange::AddValue(Value v1, Value v2) const { @@ -580,28 +616,6 @@ InductionVarRange::Value InductionVarRange::MergeVal(Value v1, Value v2, bool is return Value(); } -InductionVarRange::Value InductionVarRange::RefineOuter(Value v, bool is_min) const { - if (v.instruction == nullptr) { - return v; // nothing to refine - } - HLoopInformation* loop = - v.instruction->GetBlock()->GetLoopInformation(); // closest enveloping loop - if (loop == nullptr) { - return v; // no loop - } - HInductionVarAnalysis::InductionInfo* info = induction_analysis_->LookupInfo(loop, v.instruction); - if (info == nullptr) { - return v; // no induction information - } - // Set up loop information. - HBasicBlock* header = loop->GetHeader(); - bool in_body = true; // inner always in more outer - HInductionVarAnalysis::InductionInfo* trip = - induction_analysis_->LookupInfo(loop, header->GetLastInstruction()); - // Try to refine "a x instruction + b" with outer loop range information on instruction. - return AddValue(MulValue(Value(v.a_constant), GetVal(info, trip, in_body, is_min)), Value(v.b_constant)); -} - bool InductionVarRange::GenerateCode(HInstruction* context, HInstruction* instruction, HGraph* graph, @@ -611,27 +625,18 @@ bool InductionVarRange::GenerateCode(HInstruction* context, /*out*/HInstruction** taken_test, /*out*/bool* needs_finite_test, /*out*/bool* needs_taken_test) const { - HLoopInformation* loop = context->GetBlock()->GetLoopInformation(); // closest enveloping loop - if (loop == nullptr) { - return false; // no loop - } - HInductionVarAnalysis::InductionInfo* info = induction_analysis_->LookupInfo(loop, instruction); - if (info == nullptr) { - return false; // no induction information - } - // Set up loop information. - HBasicBlock* header = loop->GetHeader(); - bool in_body = context->GetBlock() != header; - HInductionVarAnalysis::InductionInfo* trip = - induction_analysis_->LookupInfo(loop, header->GetLastInstruction()); - if (trip == nullptr) { - return false; // codegen relies on trip count + 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(); *needs_finite_test = NeedsTripCount(info) && IsUnsafeTripCount(trip); *needs_taken_test = IsBodyTripCount(trip); // Code generation for taken test: generate the code when requested or otherwise analyze diff --git a/compiler/optimizing/induction_var_range.h b/compiler/optimizing/induction_var_range.h index 0af41560f..00aaa167f 100644 --- a/compiler/optimizing/induction_var_range.h +++ b/compiler/optimizing/induction_var_range.h @@ -57,21 +57,19 @@ class InductionVarRange { explicit InductionVarRange(HInductionVarAnalysis* induction); /** - * Given a context denoted by the first instruction, returns a possibly conservative - * lower and upper bound on the instruction's value in the output parameters min_val - * and max_val, respectively. The need_finite_test flag denotes if an additional finite-test - * is needed to protect the range evaluation inside its loop. Returns false on failure. + * Given a context denoted by the first instruction, returns a possibly conservative lower + * and upper bound on the instruction's value in the output parameters min_val and max_val, + * respectively. The need_finite_test flag denotes if an additional finite-test is needed + * to protect the range evaluation inside its loop. The parameter chase_hint defines an + * instruction at which chasing may stop. Returns false on failure. */ bool GetInductionRange(HInstruction* context, HInstruction* instruction, + HInstruction* chase_hint, /*out*/ Value* min_val, /*out*/ Value* max_val, /*out*/ bool* needs_finite_test); - /** Refines the values with induction of next outer loop. Returns true on change. */ - bool RefineOuter(/*in-out*/ Value* min_val, - /*in-out*/ Value* max_val) const; - /** * Returns true if range analysis is able to generate code for the lower and upper * bound expressions on the instruction in the given context. The need_finite_test @@ -132,11 +130,20 @@ class InductionVarRange { */ bool IsConstant(HInductionVarAnalysis::InductionInfo* info, ConstantRequest request, - /*out*/ int64_t *value) const; + /*out*/ int64_t* value) const; + + /** Returns whether induction information can be obtained. */ + bool HasInductionInfo(HInstruction* context, + HInstruction* instruction, + /*out*/ HLoopInformation** loop, + /*out*/ HInductionVarAnalysis::InductionInfo** info, + /*out*/ HInductionVarAnalysis::InductionInfo** trip) const; + bool HasFetchInLoop(HInductionVarAnalysis::InductionInfo* info) const; bool NeedsTripCount(HInductionVarAnalysis::InductionInfo* info) const; bool IsBodyTripCount(HInductionVarAnalysis::InductionInfo* trip) const; bool IsUnsafeTripCount(HInductionVarAnalysis::InductionInfo* trip) const; + bool IsWellBehavedTripCount(HInductionVarAnalysis::InductionInfo* trip) const; Value GetLinear(HInductionVarAnalysis::InductionInfo* info, HInductionVarAnalysis::InductionInfo* trip, @@ -161,8 +168,16 @@ class InductionVarRange { bool in_body, bool is_min) const; - Value MulRangeAndConstant(Value v1, Value v2, Value c, bool is_min) const; - Value DivRangeAndConstant(Value v1, Value v2, Value c, bool is_min) const; + Value MulRangeAndConstant(int64_t value, + HInductionVarAnalysis::InductionInfo* info, + HInductionVarAnalysis::InductionInfo* trip, + bool in_body, + bool is_min) const; + Value DivRangeAndConstant(int64_t value, + HInductionVarAnalysis::InductionInfo* info, + HInductionVarAnalysis::InductionInfo* trip, + bool in_body, + bool is_min) const; Value AddValue(Value v1, Value v2) const; Value SubValue(Value v1, Value v2) const; @@ -171,12 +186,6 @@ class InductionVarRange { Value MergeVal(Value v1, Value v2, bool is_min) const; /** - * Returns refined value using induction of next outer loop or the input value if no - * further refinement is possible. - */ - Value RefineOuter(Value val, bool is_min) const; - - /** * Generates code for lower/upper/taken-test in the HIR. Returns true on success. * With values nullptr, the method can be used to determine if code generation * would be successful without generating actual code yet. @@ -200,7 +209,10 @@ class InductionVarRange { bool is_min) const; /** Results of prior induction variable analysis. */ - HInductionVarAnalysis *induction_analysis_; + HInductionVarAnalysis* induction_analysis_; + + /** Instruction at which chasing may stop. */ + HInstruction* chase_hint_; friend class HInductionVarAnalysis; friend class InductionVarRangeTest; diff --git a/compiler/optimizing/induction_var_range_test.cc b/compiler/optimizing/induction_var_range_test.cc index dc04dc2c4..4ea170f65 100644 --- a/compiler/optimizing/induction_var_range_test.cc +++ b/compiler/optimizing/induction_var_range_test.cc @@ -66,6 +66,8 @@ class InductionVarRangeTest : public CommonCompilerTest { entry_block_->AddInstruction(x_); y_ = new (&allocator_) HParameterValue(graph_->GetDexFile(), 0, 0, Primitive::kPrimInt); entry_block_->AddInstruction(y_); + // Set arbitrary range analysis hint while testing private methods. + SetHint(x_); } /** Constructs loop with given upper bound. */ @@ -111,6 +113,11 @@ class InductionVarRangeTest : public CommonCompilerTest { iva_->Run(); } + /** Sets hint. */ + void SetHint(HInstruction* hint) { + range_.chase_hint_ = hint; + } + /** Constructs an invariant. */ HInductionVarAnalysis::InductionInfo* CreateInvariant(char opc, HInductionVarAnalysis::InductionInfo* a, @@ -122,6 +129,7 @@ class InductionVarRangeTest : public CommonCompilerTest { case 'n': op = HInductionVarAnalysis::kNeg; break; case '*': op = HInductionVarAnalysis::kMul; break; case '/': op = HInductionVarAnalysis::kDiv; break; + case '<': op = HInductionVarAnalysis::kLT; break; default: op = HInductionVarAnalysis::kNop; break; } return iva_->CreateInvariantOp(op, a, b); @@ -137,22 +145,21 @@ class InductionVarRangeTest : public CommonCompilerTest { return CreateFetch(graph_->GetIntConstant(c)); } - /** Constructs a trip-count. */ + /** Constructs a constant trip-count. */ HInductionVarAnalysis::InductionInfo* CreateTripCount(int32_t tc, bool in_loop, bool safe) { - Primitive::Type type = Primitive::kPrimInt; + HInductionVarAnalysis::InductionOp op = HInductionVarAnalysis::kTripCountInBodyUnsafe; if (in_loop && safe) { - return iva_->CreateTripCount( - HInductionVarAnalysis::kTripCountInLoop, CreateConst(tc), nullptr, type); + op = HInductionVarAnalysis::kTripCountInLoop; } else if (in_loop) { - return iva_->CreateTripCount( - HInductionVarAnalysis::kTripCountInLoopUnsafe, CreateConst(tc), nullptr, type); + op = HInductionVarAnalysis::kTripCountInLoopUnsafe; } else if (safe) { - return iva_->CreateTripCount( - HInductionVarAnalysis::kTripCountInBody, CreateConst(tc), nullptr, type); - } else { - return iva_->CreateTripCount( - HInductionVarAnalysis::kTripCountInBodyUnsafe, CreateConst(tc), nullptr, type); + op = HInductionVarAnalysis::kTripCountInBody; } + // Return TC with taken-test 0 < TC. + return iva_->CreateTripCount(op, + CreateConst(tc), + CreateInvariant('<', CreateConst(0), CreateConst(tc)), + Primitive::kPrimInt); } /** Constructs a linear a * i + b induction. */ @@ -197,13 +204,13 @@ class InductionVarRangeTest : public CommonCompilerTest { } Value GetMin(HInductionVarAnalysis::InductionInfo* info, - HInductionVarAnalysis::InductionInfo* induc) { - return range_.GetVal(info, induc, /* in_body */ true, /* is_min */ true); + HInductionVarAnalysis::InductionInfo* trip) { + return range_.GetVal(info, trip, /* in_body */ true, /* is_min */ true); } Value GetMax(HInductionVarAnalysis::InductionInfo* info, - HInductionVarAnalysis::InductionInfo* induc) { - return range_.GetVal(info, induc, /* in_body */ true, /* is_min */ false); + HInductionVarAnalysis::InductionInfo* trip) { + return range_.GetVal(info, trip, /* in_body */ true, /* is_min */ false); } Value GetMul(HInductionVarAnalysis::InductionInfo* info1, @@ -558,6 +565,31 @@ TEST_F(InductionVarRangeTest, MaxValue) { ExpectEqual(Value(), MaxValue(Value(55), Value(y_, 1, -50))); } +TEST_F(InductionVarRangeTest, ArrayLengthAndHints) { + HInstruction* new_array = new (&allocator_) + HNewArray(x_, + graph_->GetCurrentMethod(), + 0, Primitive::kPrimInt, + graph_->GetDexFile(), + kQuickAllocArray); + entry_block_->AddInstruction(new_array); + HInstruction* array_length = new (&allocator_) HArrayLength(new_array, 0); + entry_block_->AddInstruction(array_length); + // With null hint: yields extreme constants. + const int32_t max_value = std::numeric_limits::max(); + SetHint(nullptr); + ExpectEqual(Value(0), GetMin(CreateFetch(array_length), nullptr)); + ExpectEqual(Value(max_value), GetMax(CreateFetch(array_length), nullptr)); + // With explicit hint: yields the length instruction. + SetHint(array_length); + ExpectEqual(Value(array_length, 1, 0), GetMin(CreateFetch(array_length), nullptr)); + ExpectEqual(Value(array_length, 1, 0), GetMax(CreateFetch(array_length), nullptr)); + // With any non-null hint: chases beyond the length instruction. + SetHint(x_); + ExpectEqual(Value(x_, 1, 0), GetMin(CreateFetch(array_length), nullptr)); + ExpectEqual(Value(x_, 1, 0), GetMax(CreateFetch(array_length), nullptr)); +} + // // Tests on public methods. // @@ -570,23 +602,20 @@ TEST_F(InductionVarRangeTest, ConstantTripCountUp) { bool needs_finite_test = true; // In context of header: known. - range_.GetInductionRange(condition_, condition_->InputAt(0), &v1, &v2, &needs_finite_test); + range_.GetInductionRange(condition_, condition_->InputAt(0), x_, &v1, &v2, &needs_finite_test); EXPECT_FALSE(needs_finite_test); ExpectEqual(Value(0), v1); ExpectEqual(Value(1000), v2); - EXPECT_FALSE(range_.RefineOuter(&v1, &v2)); // In context of loop-body: known. - range_.GetInductionRange(increment_, condition_->InputAt(0), &v1, &v2, &needs_finite_test); + range_.GetInductionRange(increment_, condition_->InputAt(0), x_, &v1, &v2, &needs_finite_test); EXPECT_FALSE(needs_finite_test); ExpectEqual(Value(0), v1); ExpectEqual(Value(999), v2); - EXPECT_FALSE(range_.RefineOuter(&v1, &v2)); - range_.GetInductionRange(increment_, increment_, &v1, &v2, &needs_finite_test); + range_.GetInductionRange(increment_, increment_, x_, &v1, &v2, &needs_finite_test); EXPECT_FALSE(needs_finite_test); ExpectEqual(Value(1), v1); ExpectEqual(Value(1000), v2); - EXPECT_FALSE(range_.RefineOuter(&v1, &v2)); } TEST_F(InductionVarRangeTest, ConstantTripCountDown) { @@ -597,23 +626,20 @@ TEST_F(InductionVarRangeTest, ConstantTripCountDown) { bool needs_finite_test = true; // In context of header: known. - range_.GetInductionRange(condition_, condition_->InputAt(0), &v1, &v2, &needs_finite_test); + range_.GetInductionRange(condition_, condition_->InputAt(0), x_, &v1, &v2, &needs_finite_test); EXPECT_FALSE(needs_finite_test); ExpectEqual(Value(0), v1); ExpectEqual(Value(1000), v2); - EXPECT_FALSE(range_.RefineOuter(&v1, &v2)); // In context of loop-body: known. - range_.GetInductionRange(increment_, condition_->InputAt(0), &v1, &v2, &needs_finite_test); + range_.GetInductionRange(increment_, condition_->InputAt(0), x_, &v1, &v2, &needs_finite_test); EXPECT_FALSE(needs_finite_test); ExpectEqual(Value(1), v1); ExpectEqual(Value(1000), v2); - EXPECT_FALSE(range_.RefineOuter(&v1, &v2)); - range_.GetInductionRange(increment_, increment_, &v1, &v2, &needs_finite_test); + range_.GetInductionRange(increment_, increment_, x_, &v1, &v2, &needs_finite_test); EXPECT_FALSE(needs_finite_test); ExpectEqual(Value(0), v1); ExpectEqual(Value(999), v2); - EXPECT_FALSE(range_.RefineOuter(&v1, &v2)); } TEST_F(InductionVarRangeTest, SymbolicTripCountUp) { @@ -625,23 +651,20 @@ TEST_F(InductionVarRangeTest, SymbolicTripCountUp) { bool needs_taken_test = true; // In context of header: upper unknown. - range_.GetInductionRange(condition_, condition_->InputAt(0), &v1, &v2, &needs_finite_test); + range_.GetInductionRange(condition_, condition_->InputAt(0), x_, &v1, &v2, &needs_finite_test); EXPECT_FALSE(needs_finite_test); ExpectEqual(Value(0), v1); ExpectEqual(Value(), v2); - EXPECT_FALSE(range_.RefineOuter(&v1, &v2)); // In context of loop-body: known. - range_.GetInductionRange(increment_, condition_->InputAt(0), &v1, &v2, &needs_finite_test); + range_.GetInductionRange(increment_, condition_->InputAt(0), x_, &v1, &v2, &needs_finite_test); EXPECT_FALSE(needs_finite_test); ExpectEqual(Value(0), v1); ExpectEqual(Value(x_, 1, -1), v2); - EXPECT_FALSE(range_.RefineOuter(&v1, &v2)); - range_.GetInductionRange(increment_, increment_, &v1, &v2, &needs_finite_test); + range_.GetInductionRange(increment_, increment_, x_, &v1, &v2, &needs_finite_test); EXPECT_FALSE(needs_finite_test); ExpectEqual(Value(1), v1); ExpectEqual(Value(x_, 1, 0), v2); - EXPECT_FALSE(range_.RefineOuter(&v1, &v2)); HInstruction* lower = nullptr; HInstruction* upper = nullptr; @@ -695,23 +718,20 @@ TEST_F(InductionVarRangeTest, SymbolicTripCountDown) { bool needs_taken_test = true; // In context of header: lower unknown. - range_.GetInductionRange(condition_, condition_->InputAt(0), &v1, &v2, &needs_finite_test); + range_.GetInductionRange(condition_, condition_->InputAt(0), x_, &v1, &v2, &needs_finite_test); EXPECT_FALSE(needs_finite_test); ExpectEqual(Value(), v1); ExpectEqual(Value(1000), v2); - EXPECT_FALSE(range_.RefineOuter(&v1, &v2)); // In context of loop-body: known. - range_.GetInductionRange(increment_, condition_->InputAt(0), &v1, &v2, &needs_finite_test); + range_.GetInductionRange(increment_, condition_->InputAt(0), x_, &v1, &v2, &needs_finite_test); EXPECT_FALSE(needs_finite_test); ExpectEqual(Value(x_, 1, 1), v1); ExpectEqual(Value(1000), v2); - EXPECT_FALSE(range_.RefineOuter(&v1, &v2)); - range_.GetInductionRange(increment_, increment_, &v1, &v2, &needs_finite_test); + range_.GetInductionRange(increment_, increment_, x_, &v1, &v2, &needs_finite_test); EXPECT_FALSE(needs_finite_test); ExpectEqual(Value(x_, 1, 0), v1); ExpectEqual(Value(999), v2); - EXPECT_FALSE(range_.RefineOuter(&v1, &v2)); HInstruction* lower = nullptr; HInstruction* upper = nullptr; diff --git a/test/530-checker-loops1/src/Main.java b/test/530-checker-loops1/src/Main.java index 948a7b7dc..dde4d6247 100644 --- a/test/530-checker-loops1/src/Main.java +++ b/test/530-checker-loops1/src/Main.java @@ -562,7 +562,7 @@ public class Main { // /// CHECK-START: void Main.linearTriangularOnTwoArrayLengths(int) BCE (after) /// CHECK-NOT: BoundsCheck - // TODO: also CHECK-NOT: Deoptimize, see b/27151190 + /// CHECK-NOT: Deoptimize private static void linearTriangularOnTwoArrayLengths(int n) { int[] a = new int[n]; for (int i = 0; i < a.length; i++) { @@ -604,7 +604,7 @@ public class Main { // /// CHECK-START: void Main.linearTriangularOnParameter(int) BCE (after) /// CHECK-NOT: BoundsCheck - // TODO: also CHECK-NOT: Deoptimize, see b/27151190 + /// CHECK-NOT: Deoptimize private static void linearTriangularOnParameter(int n) { int[] a = new int[n]; for (int i = 0; i < n; i++) { @@ -619,56 +619,56 @@ public class Main { } } - /// CHECK-START: void Main.linearTriangularVariationsInnerStrict(int) BCE (before) + /// CHECK-START: void Main.linearTriangularStrictLower(int) BCE (before) /// CHECK-DAG: BoundsCheck /// CHECK-DAG: BoundsCheck /// CHECK-DAG: BoundsCheck /// CHECK-DAG: BoundsCheck // - /// CHECK-START: void Main.linearTriangularVariationsInnerStrict(int) BCE (after) + /// CHECK-START: void Main.linearTriangularStrictLower(int) BCE (after) /// CHECK-NOT: BoundsCheck - // TODO: also CHECK-NOT: Deoptimize, see b/27151190 - private static void linearTriangularVariationsInnerStrict(int n) { + /// CHECK-NOT: Deoptimize + private static void linearTriangularStrictLower(int n) { int[] a = new int[n]; for (int i = 0; i < n; i++) { for (int j = 0; j < i; j++) { a[j] += 1; } - for (int j = i - 1; j > -1; j--) { + for (int j = i - 1; j >= 0; j--) { a[j] += 1; } for (int j = i; j < n; j++) { a[j] += 1; } - for (int j = n - 1; j > i - 1; j--) { + for (int j = n - 1; j >= i; j--) { a[j] += 1; } } verifyTriangular(a); } - /// CHECK-START: void Main.linearTriangularVariationsInnerNonStrict(int) BCE (before) + /// CHECK-START: void Main.linearTriangularStrictUpper(int) BCE (before) /// CHECK-DAG: BoundsCheck /// CHECK-DAG: BoundsCheck /// CHECK-DAG: BoundsCheck /// CHECK-DAG: BoundsCheck // - /// CHECK-START: void Main.linearTriangularVariationsInnerNonStrict(int) BCE (after) + /// CHECK-START: void Main.linearTriangularStrictUpper(int) BCE (after) /// CHECK-NOT: BoundsCheck - // TODO: also CHECK-NOT: Deoptimize, see b/27151190 - private static void linearTriangularVariationsInnerNonStrict(int n) { + /// CHECK-NOT: Deoptimize + private static void linearTriangularStrictUpper(int n) { int[] a = new int[n]; for (int i = 0; i < n; i++) { - for (int j = 0; j <= i - 1; j++) { + for (int j = 0; j <= i; j++) { a[j] += 1; } - for (int j = i - 1; j >= 0; j--) { + for (int j = i; j >= 0; j--) { a[j] += 1; } - for (int j = i; j <= n - 1; j++) { + for (int j = i + 1; j < n; j++) { a[j] += 1; } - for (int j = n - 1; j >= i; j--) { + for (int j = n - 1; j >= i + 1; j--) { a[j] += 1; } } @@ -802,8 +802,8 @@ public class Main { linearTriangularOnTwoArrayLengths(10); linearTriangularOnOneArrayLength(10); linearTriangularOnParameter(10); - linearTriangularVariationsInnerStrict(10); - linearTriangularVariationsInnerNonStrict(10); + linearTriangularStrictLower(10); + linearTriangularStrictUpper(10); { int[] t = linearTriangularOOB(); for (int i = 0; i < 200; i++) { diff --git a/test/530-checker-loops2/src/Main.java b/test/530-checker-loops2/src/Main.java index b12fbd609..7acf0080f 100644 --- a/test/530-checker-loops2/src/Main.java +++ b/test/530-checker-loops2/src/Main.java @@ -31,7 +31,7 @@ public class Main { // /// CHECK-START: void Main.bubble(int[]) BCE (after) /// CHECK-NOT: BoundsCheck - // TODO: also CHECK-NOT: Deoptimize, see b/27151190 + /// CHECK-NOT: Deoptimize private static void bubble(int[] a) { for (int i = a.length; --i >= 0;) { for (int j = 0; j < i; j++) { @@ -301,6 +301,53 @@ public class Main { } while (-1 <= i); } + /// CHECK-START: void Main.justRightTriangular1() BCE (before) + /// CHECK-DAG: BoundsCheck + // + /// CHECK-START: void Main.justRightTriangular1() BCE (after) + /// CHECK-NOT: BoundsCheck + /// CHECK-NOT: Deoptimize + private static void justRightTriangular1() { + int[] a = { 1 } ; + for (int i = Integer.MIN_VALUE + 5; i <= Integer.MIN_VALUE + 10; i++) { + for (int j = Integer.MIN_VALUE + 4; j < i - 5; j++) { + sResult += a[j - (Integer.MIN_VALUE + 4)]; + } + } + } + + /// CHECK-START: void Main.justRightTriangular2() BCE (before) + /// CHECK-DAG: BoundsCheck + // + /// CHECK-START: void Main.justRightTriangular2() BCE (after) + /// CHECK-NOT: BoundsCheck + /// CHECK-NOT: Deoptimize + private static void justRightTriangular2() { + int[] a = { 1 } ; + for (int i = Integer.MIN_VALUE + 5; i <= 10; i++) { + for (int j = 4; j < i - 5; j++) { + sResult += a[j - 4]; + } + } + } + + /// CHECK-START: void Main.justOOBTriangular() BCE (before) + /// CHECK-DAG: BoundsCheck + // + /// CHECK-START: void Main.justOOBTriangular() BCE (after) + /// CHECK-DAG: Deoptimize + // + /// CHECK-START: void Main.justOOBTriangular() BCE (after) + /// CHECK-NOT: BoundsCheck + private static void justOOBTriangular() { + int[] a = { 1 } ; + for (int i = Integer.MIN_VALUE + 4; i <= 10; i++) { + for (int j = 4; j < i - 5; j++) { + sResult += a[j - 4]; + } + } + } + /// CHECK-START: void Main.hiddenOOB1(int) BCE (before) /// CHECK-DAG: BoundsCheck // @@ -315,7 +362,6 @@ public class Main { // Dangerous loop where careless static range analysis would yield strict upper bound // on index j of 5. When, for instance, lo and thus i = -2147483648, the upper bound // becomes really positive due to arithmetic wrap-around, causing OOB. - // Dynamic BCE is feasible though, since it checks the range. for (int j = 4; j < i - 5; j++) { sResult += a[j - 4]; } @@ -336,13 +382,32 @@ public class Main { // Dangerous loop where careless static range analysis would yield strict lower bound // on index j of 5. When, for instance, hi and thus i = 2147483647, the upper bound // becomes really negative due to arithmetic wrap-around, causing OOB. - // Dynamic BCE is feasible though, since it checks the range. for (int j = 6; j > i + 5; j--) { sResult += a[j - 6]; } } } + /// CHECK-START: void Main.hiddenOOB3(int) BCE (before) + /// CHECK-DAG: BoundsCheck + // + /// CHECK-START: void Main.hiddenOOB3(int) BCE (after) + /// CHECK-DAG: Deoptimize + // + /// CHECK-START: void Main.hiddenOOB3(int) BCE (after) + /// CHECK-NOT: BoundsCheck + private static void hiddenOOB3(int hi) { + int[] a = { 11 } ; + for (int i = -1; i <= hi; i++) { + // Dangerous loop where careless static range analysis would yield strict lower bound + // on index j of 0. For large i, the initial value of j becomes really negative due + // to arithmetic wrap-around, causing OOB. + for (int j = i + 1; j < 1; j++) { + sResult += a[j]; + } + } + } + /// CHECK-START: void Main.hiddenInfiniteOOB() BCE (before) /// CHECK-DAG: BoundsCheck // @@ -376,7 +441,6 @@ public class Main { for (int i = -1; i <= 0; i++) { // Dangerous loop similar as above where the loop is now finite, but the // loop still goes out of bounds for i = -1 due to the large upper bound. - // Dynamic BCE is feasible though, since it checks the range. for (int j = -4; j < 2147483646 * i - 3; j++) { sResult += a[j + 4]; } @@ -432,6 +496,25 @@ public class Main { } } + /// CHECK-START: int Main.doNotHoist(int[]) BCE (before) + /// CHECK-DAG: BoundsCheck + // + /// CHECK-START: int Main.doNotHoist(int[]) BCE (after) + /// CHECK-NOT: BoundsCheck + public static int doNotHoist(int[] a) { + int n = a.length; + int x = 0; + // BCE applies, but hoisting would crash the loop. + for (int i = -10000; i < 10000; i++) { + for (int j = 0; j <= 1; j++) { + if (0 <= i && i < n) + x += a[i]; + } + } + return x; + } + + /// CHECK-START: int[] Main.add() BCE (before) /// CHECK-DAG: BoundsCheck // @@ -687,7 +770,7 @@ public class Main { /// CHECK-START: int Main.dynamicBCEAndConstantIndices(int[], int[][], int, int) BCE (after) // Order matters: /// CHECK: Deoptimize loop:<> - // CHECK-NOT: Goto loop:<> + /// CHECK-NOT: Goto loop:<> /// CHECK-DAG: {{l\d+}} ArrayGet loop:<> /// CHECK-DAG: {{l\d+}} ArrayGet loop:<> /// CHECK-DAG: {{l\d+}} ArrayGet loop:<> @@ -839,6 +922,8 @@ public class Main { expectEquals(55, justRightDown1()); expectEquals(55, justRightDown2()); expectEquals(55, justRightDown3()); + + // Large bounds OOB. sResult = 0; try { justOOBUp(); @@ -890,6 +975,23 @@ public class Main { } expectEquals(1055, sResult); + // Triangular. + sResult = 0; + justRightTriangular1(); + expectEquals(1, sResult); + if (HEAVY) { + sResult = 0; + justRightTriangular2(); + expectEquals(1, sResult); + } + sResult = 0; + try { + justOOBTriangular(); + } catch (ArrayIndexOutOfBoundsException e) { + sResult += 1000; + } + expectEquals(1001, sResult); + // Hidden OOB. sResult = 0; try { @@ -912,6 +1014,15 @@ public class Main { sResult += 1000; } expectEquals(1, sResult); + sResult = 0; + try { + hiddenOOB3(-1); // no OOB + } catch (ArrayIndexOutOfBoundsException e) { + sResult += 1000; + } + expectEquals(11, sResult); + + // Expensive hidden OOB test. if (HEAVY) { sResult = 0; try { @@ -920,7 +1031,16 @@ public class Main { sResult += 1000; } expectEquals(1002, sResult); + sResult = 0; + try { + hiddenOOB3(2147483647); // OOB + } catch (ArrayIndexOutOfBoundsException e) { + sResult += 1000; + } + expectEquals(1011, sResult); } + + // More hidden OOB. sResult = 0; try { hiddenInfiniteOOB(); @@ -966,6 +1086,9 @@ public class Main { expectEquals(i < 128 ? i : 0, a200[i]); } + // No hoisting after BCE. + expectEquals(110, doNotHoist(x)); + // Addition. { int[] e1 ={ 1, 2, 3, 4, 4, 4, 4, 3, 2, 1 };