| // Copyright 2014 the V8 project authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "src/compiler/common-operator-reducer.h" |
| |
| #include <algorithm> |
| |
| #include "src/compiler/common-operator.h" |
| #include "src/compiler/graph.h" |
| #include "src/compiler/machine-operator.h" |
| #include "src/compiler/node.h" |
| #include "src/compiler/node-matchers.h" |
| #include "src/compiler/node-properties.h" |
| |
| namespace v8 { |
| namespace internal { |
| namespace compiler { |
| |
| namespace { |
| |
| Decision DecideCondition(Node* const cond) { |
| switch (cond->opcode()) { |
| case IrOpcode::kInt32Constant: { |
| Int32Matcher mcond(cond); |
| return mcond.Value() ? Decision::kTrue : Decision::kFalse; |
| } |
| case IrOpcode::kHeapConstant: { |
| HeapObjectMatcher mcond(cond); |
| return mcond.Value()->BooleanValue() ? Decision::kTrue : Decision::kFalse; |
| } |
| default: |
| return Decision::kUnknown; |
| } |
| } |
| |
| } // namespace |
| |
| |
| CommonOperatorReducer::CommonOperatorReducer(Editor* editor, Graph* graph, |
| CommonOperatorBuilder* common, |
| MachineOperatorBuilder* machine) |
| : AdvancedReducer(editor), |
| graph_(graph), |
| common_(common), |
| machine_(machine), |
| dead_(graph->NewNode(common->Dead())) {} |
| |
| |
| Reduction CommonOperatorReducer::Reduce(Node* node) { |
| switch (node->opcode()) { |
| case IrOpcode::kBranch: |
| return ReduceBranch(node); |
| case IrOpcode::kDeoptimizeIf: |
| case IrOpcode::kDeoptimizeUnless: |
| return ReduceDeoptimizeConditional(node); |
| case IrOpcode::kMerge: |
| return ReduceMerge(node); |
| case IrOpcode::kEffectPhi: |
| return ReduceEffectPhi(node); |
| case IrOpcode::kPhi: |
| return ReducePhi(node); |
| case IrOpcode::kReturn: |
| return ReduceReturn(node); |
| case IrOpcode::kSelect: |
| return ReduceSelect(node); |
| default: |
| break; |
| } |
| return NoChange(); |
| } |
| |
| |
| Reduction CommonOperatorReducer::ReduceBranch(Node* node) { |
| DCHECK_EQ(IrOpcode::kBranch, node->opcode()); |
| Node* const cond = node->InputAt(0); |
| // Swap IfTrue/IfFalse on {branch} if {cond} is a BooleanNot and use the input |
| // to BooleanNot as new condition for {branch}. Note we assume that {cond} was |
| // already properly optimized before we get here (as guaranteed by the graph |
| // reduction logic). |
| if (cond->opcode() == IrOpcode::kBooleanNot) { |
| for (Node* const use : node->uses()) { |
| switch (use->opcode()) { |
| case IrOpcode::kIfTrue: |
| NodeProperties::ChangeOp(use, common()->IfFalse()); |
| break; |
| case IrOpcode::kIfFalse: |
| NodeProperties::ChangeOp(use, common()->IfTrue()); |
| break; |
| default: |
| UNREACHABLE(); |
| } |
| } |
| // Update the condition of {branch}. No need to mark the uses for revisit, |
| // since we tell the graph reducer that the {branch} was changed and the |
| // graph reduction logic will ensure that the uses are revisited properly. |
| node->ReplaceInput(0, cond->InputAt(0)); |
| // Negate the hint for {branch}. |
| NodeProperties::ChangeOp( |
| node, common()->Branch(NegateBranchHint(BranchHintOf(node->op())))); |
| return Changed(node); |
| } |
| Decision const decision = DecideCondition(cond); |
| if (decision == Decision::kUnknown) return NoChange(); |
| Node* const control = node->InputAt(1); |
| for (Node* const use : node->uses()) { |
| switch (use->opcode()) { |
| case IrOpcode::kIfTrue: |
| Replace(use, (decision == Decision::kTrue) ? control : dead()); |
| break; |
| case IrOpcode::kIfFalse: |
| Replace(use, (decision == Decision::kFalse) ? control : dead()); |
| break; |
| default: |
| UNREACHABLE(); |
| } |
| } |
| return Replace(dead()); |
| } |
| |
| Reduction CommonOperatorReducer::ReduceDeoptimizeConditional(Node* node) { |
| DCHECK(node->opcode() == IrOpcode::kDeoptimizeIf || |
| node->opcode() == IrOpcode::kDeoptimizeUnless); |
| bool condition_is_true = node->opcode() == IrOpcode::kDeoptimizeUnless; |
| Node* condition = NodeProperties::GetValueInput(node, 0); |
| Node* frame_state = NodeProperties::GetValueInput(node, 1); |
| Node* effect = NodeProperties::GetEffectInput(node); |
| Node* control = NodeProperties::GetControlInput(node); |
| // Swap DeoptimizeIf/DeoptimizeUnless on {node} if {cond} is a BooleaNot |
| // and use the input to BooleanNot as new condition for {node}. Note we |
| // assume that {cond} was already properly optimized before we get here |
| // (as guaranteed by the graph reduction logic). |
| if (condition->opcode() == IrOpcode::kBooleanNot) { |
| NodeProperties::ReplaceValueInput(node, condition->InputAt(0), 0); |
| NodeProperties::ChangeOp(node, condition_is_true |
| ? common()->DeoptimizeIf() |
| : common()->DeoptimizeUnless()); |
| return Changed(node); |
| } |
| Decision const decision = DecideCondition(condition); |
| if (decision == Decision::kUnknown) return NoChange(); |
| if (condition_is_true == (decision == Decision::kTrue)) { |
| ReplaceWithValue(node, dead(), effect, control); |
| } else { |
| control = graph()->NewNode(common()->Deoptimize(DeoptimizeKind::kEager), |
| frame_state, effect, control); |
| // TODO(bmeurer): This should be on the AdvancedReducer somehow. |
| NodeProperties::MergeControlToEnd(graph(), common(), control); |
| Revisit(graph()->end()); |
| } |
| return Replace(dead()); |
| } |
| |
| Reduction CommonOperatorReducer::ReduceMerge(Node* node) { |
| DCHECK_EQ(IrOpcode::kMerge, node->opcode()); |
| // |
| // Check if this is a merge that belongs to an unused diamond, which means |
| // that: |
| // |
| // a) the {Merge} has no {Phi} or {EffectPhi} uses, and |
| // b) the {Merge} has two inputs, one {IfTrue} and one {IfFalse}, which are |
| // both owned by the Merge, and |
| // c) and the {IfTrue} and {IfFalse} nodes point to the same {Branch}. |
| // |
| if (node->InputCount() == 2) { |
| for (Node* const use : node->uses()) { |
| if (IrOpcode::IsPhiOpcode(use->opcode())) return NoChange(); |
| } |
| Node* if_true = node->InputAt(0); |
| Node* if_false = node->InputAt(1); |
| if (if_true->opcode() != IrOpcode::kIfTrue) std::swap(if_true, if_false); |
| if (if_true->opcode() == IrOpcode::kIfTrue && |
| if_false->opcode() == IrOpcode::kIfFalse && |
| if_true->InputAt(0) == if_false->InputAt(0) && if_true->OwnedBy(node) && |
| if_false->OwnedBy(node)) { |
| Node* const branch = if_true->InputAt(0); |
| DCHECK_EQ(IrOpcode::kBranch, branch->opcode()); |
| DCHECK(branch->OwnedBy(if_true, if_false)); |
| Node* const control = branch->InputAt(1); |
| // Mark the {branch} as {Dead}. |
| branch->TrimInputCount(0); |
| NodeProperties::ChangeOp(branch, common()->Dead()); |
| return Replace(control); |
| } |
| } |
| return NoChange(); |
| } |
| |
| |
| Reduction CommonOperatorReducer::ReduceEffectPhi(Node* node) { |
| DCHECK_EQ(IrOpcode::kEffectPhi, node->opcode()); |
| int const input_count = node->InputCount() - 1; |
| DCHECK_LE(1, input_count); |
| Node* const merge = node->InputAt(input_count); |
| DCHECK(IrOpcode::IsMergeOpcode(merge->opcode())); |
| DCHECK_EQ(input_count, merge->InputCount()); |
| Node* const effect = node->InputAt(0); |
| DCHECK_NE(node, effect); |
| for (int i = 1; i < input_count; ++i) { |
| Node* const input = node->InputAt(i); |
| if (input == node) { |
| // Ignore redundant inputs. |
| DCHECK_EQ(IrOpcode::kLoop, merge->opcode()); |
| continue; |
| } |
| if (input != effect) return NoChange(); |
| } |
| // We might now be able to further reduce the {merge} node. |
| Revisit(merge); |
| return Replace(effect); |
| } |
| |
| |
| Reduction CommonOperatorReducer::ReducePhi(Node* node) { |
| DCHECK_EQ(IrOpcode::kPhi, node->opcode()); |
| int const input_count = node->InputCount() - 1; |
| DCHECK_LE(1, input_count); |
| Node* const merge = node->InputAt(input_count); |
| DCHECK(IrOpcode::IsMergeOpcode(merge->opcode())); |
| DCHECK_EQ(input_count, merge->InputCount()); |
| if (input_count == 2) { |
| Node* vtrue = node->InputAt(0); |
| Node* vfalse = node->InputAt(1); |
| Node* if_true = merge->InputAt(0); |
| Node* if_false = merge->InputAt(1); |
| if (if_true->opcode() != IrOpcode::kIfTrue) { |
| std::swap(if_true, if_false); |
| std::swap(vtrue, vfalse); |
| } |
| if (if_true->opcode() == IrOpcode::kIfTrue && |
| if_false->opcode() == IrOpcode::kIfFalse && |
| if_true->InputAt(0) == if_false->InputAt(0)) { |
| Node* const branch = if_true->InputAt(0); |
| // Check that the branch is not dead already. |
| if (branch->opcode() != IrOpcode::kBranch) return NoChange(); |
| Node* const cond = branch->InputAt(0); |
| if (cond->opcode() == IrOpcode::kFloat32LessThan) { |
| Float32BinopMatcher mcond(cond); |
| if (mcond.left().Is(0.0) && mcond.right().Equals(vtrue) && |
| vfalse->opcode() == IrOpcode::kFloat32Sub) { |
| Float32BinopMatcher mvfalse(vfalse); |
| if (mvfalse.left().IsZero() && mvfalse.right().Equals(vtrue)) { |
| // We might now be able to further reduce the {merge} node. |
| Revisit(merge); |
| return Change(node, machine()->Float32Abs(), vtrue); |
| } |
| } |
| if (mcond.left().Equals(vtrue) && mcond.right().Equals(vfalse) && |
| machine()->Float32Min().IsSupported()) { |
| // We might now be able to further reduce the {merge} node. |
| Revisit(merge); |
| return Change(node, machine()->Float32Min().op(), vtrue, vfalse); |
| } else if (mcond.left().Equals(vfalse) && mcond.right().Equals(vtrue) && |
| machine()->Float32Max().IsSupported()) { |
| // We might now be able to further reduce the {merge} node. |
| Revisit(merge); |
| return Change(node, machine()->Float32Max().op(), vtrue, vfalse); |
| } |
| } else if (cond->opcode() == IrOpcode::kFloat64LessThan) { |
| Float64BinopMatcher mcond(cond); |
| if (mcond.left().Is(0.0) && mcond.right().Equals(vtrue) && |
| vfalse->opcode() == IrOpcode::kFloat64Sub) { |
| Float64BinopMatcher mvfalse(vfalse); |
| if (mvfalse.left().IsZero() && mvfalse.right().Equals(vtrue)) { |
| // We might now be able to further reduce the {merge} node. |
| Revisit(merge); |
| return Change(node, machine()->Float64Abs(), vtrue); |
| } |
| } |
| if (mcond.left().Equals(vtrue) && mcond.right().Equals(vfalse) && |
| machine()->Float64Min().IsSupported()) { |
| // We might now be able to further reduce the {merge} node. |
| Revisit(merge); |
| return Change(node, machine()->Float64Min().op(), vtrue, vfalse); |
| } else if (mcond.left().Equals(vfalse) && mcond.right().Equals(vtrue) && |
| machine()->Float64Max().IsSupported()) { |
| // We might now be able to further reduce the {merge} node. |
| Revisit(merge); |
| return Change(node, machine()->Float64Max().op(), vtrue, vfalse); |
| } |
| } |
| } |
| } |
| Node* const value = node->InputAt(0); |
| DCHECK_NE(node, value); |
| for (int i = 1; i < input_count; ++i) { |
| Node* const input = node->InputAt(i); |
| if (input == node) { |
| // Ignore redundant inputs. |
| DCHECK_EQ(IrOpcode::kLoop, merge->opcode()); |
| continue; |
| } |
| if (input != value) return NoChange(); |
| } |
| // We might now be able to further reduce the {merge} node. |
| Revisit(merge); |
| return Replace(value); |
| } |
| |
| |
| Reduction CommonOperatorReducer::ReduceReturn(Node* node) { |
| DCHECK_EQ(IrOpcode::kReturn, node->opcode()); |
| Node* const value = node->InputAt(0); |
| Node* const effect = node->InputAt(1); |
| Node* const control = node->InputAt(2); |
| if (value->opcode() == IrOpcode::kPhi && |
| NodeProperties::GetControlInput(value) == control && |
| effect->opcode() == IrOpcode::kEffectPhi && |
| NodeProperties::GetControlInput(effect) == control && |
| control->opcode() == IrOpcode::kMerge) { |
| int const control_input_count = control->InputCount(); |
| DCHECK_NE(0, control_input_count); |
| DCHECK_EQ(control_input_count, value->InputCount() - 1); |
| DCHECK_EQ(control_input_count, effect->InputCount() - 1); |
| DCHECK_EQ(IrOpcode::kEnd, graph()->end()->opcode()); |
| DCHECK_NE(0, graph()->end()->InputCount()); |
| for (int i = 0; i < control_input_count; ++i) { |
| // Create a new {Return} and connect it to {end}. We don't need to mark |
| // {end} as revisit, because we mark {node} as {Dead} below, which was |
| // previously connected to {end}, so we know for sure that at some point |
| // the reducer logic will visit {end} again. |
| Node* ret = graph()->NewNode(common()->Return(), value->InputAt(i), |
| effect->InputAt(i), control->InputAt(i)); |
| NodeProperties::MergeControlToEnd(graph(), common(), ret); |
| } |
| // Mark the merge {control} and return {node} as {dead}. |
| Replace(control, dead()); |
| return Replace(dead()); |
| } |
| return NoChange(); |
| } |
| |
| |
| Reduction CommonOperatorReducer::ReduceSelect(Node* node) { |
| DCHECK_EQ(IrOpcode::kSelect, node->opcode()); |
| Node* const cond = node->InputAt(0); |
| Node* const vtrue = node->InputAt(1); |
| Node* const vfalse = node->InputAt(2); |
| if (vtrue == vfalse) return Replace(vtrue); |
| switch (DecideCondition(cond)) { |
| case Decision::kTrue: |
| return Replace(vtrue); |
| case Decision::kFalse: |
| return Replace(vfalse); |
| case Decision::kUnknown: |
| break; |
| } |
| switch (cond->opcode()) { |
| case IrOpcode::kFloat32LessThan: { |
| Float32BinopMatcher mcond(cond); |
| if (mcond.left().Is(0.0) && mcond.right().Equals(vtrue) && |
| vfalse->opcode() == IrOpcode::kFloat32Sub) { |
| Float32BinopMatcher mvfalse(vfalse); |
| if (mvfalse.left().IsZero() && mvfalse.right().Equals(vtrue)) { |
| return Change(node, machine()->Float32Abs(), vtrue); |
| } |
| } |
| if (mcond.left().Equals(vtrue) && mcond.right().Equals(vfalse) && |
| machine()->Float32Min().IsSupported()) { |
| return Change(node, machine()->Float32Min().op(), vtrue, vfalse); |
| } else if (mcond.left().Equals(vfalse) && mcond.right().Equals(vtrue) && |
| machine()->Float32Max().IsSupported()) { |
| return Change(node, machine()->Float32Max().op(), vtrue, vfalse); |
| } |
| break; |
| } |
| case IrOpcode::kFloat64LessThan: { |
| Float64BinopMatcher mcond(cond); |
| if (mcond.left().Is(0.0) && mcond.right().Equals(vtrue) && |
| vfalse->opcode() == IrOpcode::kFloat64Sub) { |
| Float64BinopMatcher mvfalse(vfalse); |
| if (mvfalse.left().IsZero() && mvfalse.right().Equals(vtrue)) { |
| return Change(node, machine()->Float64Abs(), vtrue); |
| } |
| } |
| if (mcond.left().Equals(vtrue) && mcond.right().Equals(vfalse) && |
| machine()->Float64Min().IsSupported()) { |
| return Change(node, machine()->Float64Min().op(), vtrue, vfalse); |
| } else if (mcond.left().Equals(vfalse) && mcond.right().Equals(vtrue) && |
| machine()->Float64Max().IsSupported()) { |
| return Change(node, machine()->Float64Max().op(), vtrue, vfalse); |
| } |
| break; |
| } |
| default: |
| break; |
| } |
| return NoChange(); |
| } |
| |
| |
| Reduction CommonOperatorReducer::Change(Node* node, Operator const* op, |
| Node* a) { |
| node->ReplaceInput(0, a); |
| node->TrimInputCount(1); |
| NodeProperties::ChangeOp(node, op); |
| return Changed(node); |
| } |
| |
| |
| Reduction CommonOperatorReducer::Change(Node* node, Operator const* op, Node* a, |
| Node* b) { |
| node->ReplaceInput(0, a); |
| node->ReplaceInput(1, b); |
| node->TrimInputCount(2); |
| NodeProperties::ChangeOp(node, op); |
| return Changed(node); |
| } |
| |
| } // namespace compiler |
| } // namespace internal |
| } // namespace v8 |