[turbofan] Support for combining branches with <Operation>WithOverflow.

Also unify the handling of binops in the InstructionSelector
backends.

TEST=cctest/test-run-machops,cctest/test-instruction-selector-arm
R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/415403005

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22800 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/compiler/arm/instruction-selector-arm.cc

@@ -249,46 +249,12 @@ static inline bool TryMatchImmediateOrShift(InstructionSelector* selector,
 }
 
 
-// Shared routine for multiple binary operations.
 static void VisitBinop(InstructionSelector* selector, Node* node,
-                       InstructionCode opcode, InstructionCode reverse_opcode) {
-  ArmOperandGenerator g(selector);
-  Int32BinopMatcher m(node);
-  InstructionOperand* inputs[3];
-  size_t input_count = 0;
-  InstructionOperand* outputs[1] = {g.DefineAsRegister(node)};
-  const size_t output_count = ARRAY_SIZE(outputs);
-
-  if (TryMatchImmediateOrShift(selector, &opcode, m.right().node(),
-                               &input_count, &inputs[1])) {
-    inputs[0] = g.UseRegister(m.left().node());
-    input_count++;
-  } else if (TryMatchImmediateOrShift(selector, &reverse_opcode,
-                                      m.left().node(), &input_count,
-                                      &inputs[1])) {
-    inputs[0] = g.UseRegister(m.right().node());
-    opcode = reverse_opcode;
-    input_count++;
-  } else {
-    opcode |= AddressingModeField::encode(kMode_Operand2_R);
-    inputs[input_count++] = g.UseRegister(m.left().node());
-    inputs[input_count++] = g.UseRegister(m.right().node());
-  }
-
-  ASSERT_NE(0, input_count);
-  ASSERT_GE(ARRAY_SIZE(inputs), input_count);
-  ASSERT_NE(kMode_None, AddressingModeField::decode(opcode));
-
-  selector->Emit(opcode, output_count, outputs, input_count, inputs);
-}
-
-
-static void VisitBinopWithOverflow(InstructionSelector* selector, Node* node,
-                                   InstructionCode opcode,
-                                   InstructionCode reverse_opcode) {
+                       InstructionCode opcode, InstructionCode reverse_opcode,
+                       FlagsContinuation* cont) {
   ArmOperandGenerator g(selector);
   Int32BinopMatcher m(node);
-  InstructionOperand* inputs[3];
+  InstructionOperand* inputs[5];
   size_t input_count = 0;
   InstructionOperand* outputs[2];
   size_t output_count = 0;
@@ -309,16 +275,14 @@ static void VisitBinopWithOverflow(InstructionSelector* selector, Node* node,
     inputs[input_count++] = g.UseRegister(m.right().node());
   }
 
-  // Define outputs depending on the projections.
-  Node* projections[2];
-  node->CollectProjections(ARRAY_SIZE(projections), projections);
-  if (projections[0]) {
-    outputs[output_count++] = g.DefineAsRegister(projections[0]);
+  if (cont->IsBranch()) {
+    inputs[input_count++] = g.Label(cont->true_block());
+    inputs[input_count++] = g.Label(cont->false_block());
   }
-  if (projections[1]) {
-    opcode |= FlagsModeField::encode(kFlags_set);
-    opcode |= FlagsConditionField::encode(kOverflow);
-    outputs[output_count++] = g.DefineAsRegister(projections[1]);
+
+  outputs[output_count++] = g.DefineAsRegister(node);
+  if (cont->IsSet()) {
+    outputs[output_count++] = g.DefineAsRegister(cont->result());
   }
 
   ASSERT_NE(0, input_count);
@@ -327,7 +291,16 @@ static void VisitBinopWithOverflow(InstructionSelector* selector, Node* node,
   ASSERT_GE(ARRAY_SIZE(outputs), output_count);
   ASSERT_NE(kMode_None, AddressingModeField::decode(opcode));
 
-  selector->Emit(opcode, output_count, outputs, input_count, inputs);
+  Instruction* instr = selector->Emit(cont->Encode(opcode), output_count,
+                                      outputs, input_count, inputs);
+  if (cont->IsBranch()) instr->MarkAsControl();
+}
+
+
+static void VisitBinop(InstructionSelector* selector, Node* node,
+                       InstructionCode opcode, InstructionCode reverse_opcode) {
+  FlagsContinuation cont;
+  VisitBinop(selector, node, opcode, reverse_opcode, &cont);
 }
 
 
@@ -597,11 +570,6 @@ void InstructionSelector::VisitInt32Add(Node* node) {
 }
 
 
-void InstructionSelector::VisitInt32AddWithOverflow(Node* node) {
-  VisitBinopWithOverflow(this, node, kArmAdd, kArmAdd);
-}
-
-
 void InstructionSelector::VisitInt32Sub(Node* node) {
   ArmOperandGenerator g(this);
   Int32BinopMatcher m(node);
@@ -616,11 +584,6 @@ void InstructionSelector::VisitInt32Sub(Node* node) {
 }
 
 
-void InstructionSelector::VisitInt32SubWithOverflow(Node* node) {
-  VisitBinopWithOverflow(this, node, kArmSub, kArmRsb);
-}
-
-
 void InstructionSelector::VisitInt32Mul(Node* node) {
   ArmOperandGenerator g(this);
   Int32BinopMatcher m(node);
@@ -867,10 +830,22 @@ void InstructionSelector::VisitCall(Node* call, BasicBlock* continuation,
 }
 
 
+void InstructionSelector::VisitInt32AddWithOverflow(Node* node,
+                                                    FlagsContinuation* cont) {
+  VisitBinop(this, node, kArmAdd, kArmAdd, cont);
+}
+
+
+void InstructionSelector::VisitInt32SubWithOverflow(Node* node,
+                                                    FlagsContinuation* cont) {
+  VisitBinop(this, node, kArmSub, kArmRsb, cont);
+}
+
+
 // Shared routine for multiple compare operations.
 static void VisitWordCompare(InstructionSelector* selector, Node* node,
                              InstructionCode opcode, FlagsContinuation* cont,
-                             bool commutative, bool requires_output) {
+                             bool commutative) {
   ArmOperandGenerator g(selector);
   Int32BinopMatcher m(node);
   InstructionOperand* inputs[5];
@@ -894,9 +869,6 @@ static void VisitWordCompare(InstructionSelector* selector, Node* node,
   }
 
   if (cont->IsBranch()) {
-    if (requires_output) {
-      outputs[output_count++] = g.DefineAsRegister(node);
-    }
     inputs[input_count++] = g.Label(cont->true_block());
     inputs[input_count++] = g.Label(cont->false_block());
   } else {
@@ -917,15 +889,15 @@ static void VisitWordCompare(InstructionSelector* selector, Node* node,
 void InstructionSelector::VisitWord32Test(Node* node, FlagsContinuation* cont) {
   switch (node->opcode()) {
     case IrOpcode::kInt32Add:
-      return VisitWordCompare(this, node, kArmCmn, cont, true, false);
+      return VisitWordCompare(this, node, kArmCmn, cont, true);
     case IrOpcode::kInt32Sub:
-      return VisitWordCompare(this, node, kArmCmp, cont, false, false);
+      return VisitWordCompare(this, node, kArmCmp, cont, false);
     case IrOpcode::kWord32And:
-      return VisitWordCompare(this, node, kArmTst, cont, true, false);
+      return VisitWordCompare(this, node, kArmTst, cont, true);
     case IrOpcode::kWord32Or:
-      return VisitWordCompare(this, node, kArmOrr, cont, true, true);
+      return VisitBinop(this, node, kArmOrr, kArmOrr, cont);
     case IrOpcode::kWord32Xor:
-      return VisitWordCompare(this, node, kArmTeq, cont, true, false);
+      return VisitWordCompare(this, node, kArmTeq, cont, true);
     default:
       break;
   }
@@ -946,7 +918,7 @@ void InstructionSelector::VisitWord32Test(Node* node, FlagsContinuation* cont) {
 
 void InstructionSelector::VisitWord32Compare(Node* node,
                                              FlagsContinuation* cont) {
-  VisitWordCompare(this, node, kArmCmp, cont, false, false);
+  VisitWordCompare(this, node, kArmCmp, cont, false);
 }
 
 

src/compiler/arm64/instruction-selector-arm64.cc

@@ -110,34 +110,26 @@ static void VisitRRO(InstructionSelector* selector, ArchOpcode opcode,
 
 // Shared routine for multiple binary operations.
 static void VisitBinop(InstructionSelector* selector, Node* node,
-                       ArchOpcode opcode, ImmediateMode operand_mode,
-                       bool commutative) {
-  VisitRRO(selector, opcode, node, operand_mode);
-}
-
-
-static void VisitBinopWithOverflow(InstructionSelector* selector, Node* node,
-                                   InstructionCode opcode) {
+                       InstructionCode opcode, ImmediateMode operand_mode,
+                       FlagsContinuation* cont) {
   Arm64OperandGenerator g(selector);
   Int32BinopMatcher m(node);
-  InstructionOperand* inputs[2];
+  InstructionOperand* inputs[4];
   size_t input_count = 0;
   InstructionOperand* outputs[2];
   size_t output_count = 0;
 
   inputs[input_count++] = g.UseRegister(m.left().node());
-  inputs[input_count++] = g.UseRegister(m.right().node());
+  inputs[input_count++] = g.UseOperand(m.right().node(), operand_mode);
 
-  // Define outputs depending on the projections.
-  Node* projections[2];
-  node->CollectProjections(ARRAY_SIZE(projections), projections);
-  if (projections[0]) {
-    outputs[output_count++] = g.DefineAsRegister(projections[0]);
+  if (cont->IsBranch()) {
+    inputs[input_count++] = g.Label(cont->true_block());
+    inputs[input_count++] = g.Label(cont->false_block());
   }
-  if (projections[1]) {
-    opcode |= FlagsModeField::encode(kFlags_set);
-    opcode |= FlagsConditionField::encode(kOverflow);
-    outputs[output_count++] = g.DefineAsRegister(projections[1]);
+
+  outputs[output_count++] = g.DefineAsRegister(node);
+  if (cont->IsSet()) {
+    outputs[output_count++] = g.DefineAsRegister(cont->result());
   }
 
   ASSERT_NE(0, input_count);
@@ -145,7 +137,17 @@ static void VisitBinopWithOverflow(InstructionSelector* selector, Node* node,
   ASSERT_GE(ARRAY_SIZE(inputs), input_count);
   ASSERT_GE(ARRAY_SIZE(outputs), output_count);
 
-  selector->Emit(opcode, output_count, outputs, input_count, inputs);
+  Instruction* instr = selector->Emit(cont->Encode(opcode), output_count,
+                                      outputs, input_count, inputs);
+  if (cont->IsBranch()) instr->MarkAsControl();
+}
+
+
+// Shared routine for multiple binary operations.
+static void VisitBinop(InstructionSelector* selector, Node* node,
+                       ArchOpcode opcode, ImmediateMode operand_mode) {
+  FlagsContinuation cont;
+  VisitBinop(selector, node, opcode, operand_mode);
 }
 
 
@@ -256,22 +258,22 @@ void InstructionSelector::VisitStore(Node* node) {
 
 
 void InstructionSelector::VisitWord32And(Node* node) {
-  VisitBinop(this, node, kArm64And32, kLogical32Imm, true);
+  VisitBinop(this, node, kArm64And32, kLogical32Imm);
 }
 
 
 void InstructionSelector::VisitWord64And(Node* node) {
-  VisitBinop(this, node, kArm64And, kLogical64Imm, true);
+  VisitBinop(this, node, kArm64And, kLogical64Imm);
 }
 
 
 void InstructionSelector::VisitWord32Or(Node* node) {
-  VisitBinop(this, node, kArm64Or32, kLogical32Imm, true);
+  VisitBinop(this, node, kArm64Or32, kLogical32Imm);
 }
 
 
 void InstructionSelector::VisitWord64Or(Node* node) {
-  VisitBinop(this, node, kArm64Or, kLogical64Imm, true);
+  VisitBinop(this, node, kArm64Or, kLogical64Imm);
 }
 
 
@@ -284,7 +286,7 @@ static void VisitXor(InstructionSelector* selector, Node* node,
     selector->Emit(not_opcode, g.DefineAsRegister(node),
                    g.UseRegister(m.left().node()));
   } else {
-    VisitBinop(selector, node, xor_opcode, kLogical32Imm, true);
+    VisitBinop(selector, node, xor_opcode, kLogical32Imm);
   }
 }
 
@@ -330,17 +332,12 @@ void InstructionSelector::VisitWord64Sar(Node* node) {
 
 
 void InstructionSelector::VisitInt32Add(Node* node) {
-  VisitBinop(this, node, kArm64Add32, kArithimeticImm, true);
-}
-
-
-void InstructionSelector::VisitInt32AddWithOverflow(Node* node) {
-  VisitBinopWithOverflow(this, node, kArm64Add32);
+  VisitBinop(this, node, kArm64Add32, kArithimeticImm);
 }
 
 
 void InstructionSelector::VisitInt64Add(Node* node) {
-  VisitBinop(this, node, kArm64Add, kArithimeticImm, true);
+  VisitBinop(this, node, kArm64Add, kArithimeticImm);
 }
 
 
@@ -353,7 +350,7 @@ static void VisitSub(InstructionSelector* selector, Node* node,
     selector->Emit(neg_opcode, g.DefineAsRegister(node),
                    g.UseRegister(m.right().node()));
   } else {
-    VisitBinop(selector, node, sub_opcode, kArithimeticImm, false);
+    VisitBinop(selector, node, sub_opcode, kArithimeticImm);
   }
 }
 
@@ -363,11 +360,6 @@ void InstructionSelector::VisitInt32Sub(Node* node) {
 }
 
 
-void InstructionSelector::VisitInt32SubWithOverflow(Node* node) {
-  VisitBinopWithOverflow(this, node, kArm64Sub32);
-}
-
-
 void InstructionSelector::VisitInt64Sub(Node* node) {
   VisitSub<int64_t>(this, node, kArm64Sub, kArm64Neg);
 }
@@ -489,6 +481,18 @@ void InstructionSelector::VisitFloat64Mod(Node* node) {
 }
 
 
+void InstructionSelector::VisitInt32AddWithOverflow(Node* node,
+                                                    FlagsContinuation* cont) {
+  VisitBinop(this, node, kArm64Add32, kArithimeticImm, cont);
+}
+
+
+void InstructionSelector::VisitInt32SubWithOverflow(Node* node,
+                                                    FlagsContinuation* cont) {
+  VisitBinop(this, node, kArm64Sub32, kArithimeticImm, cont);
+}
+
+
 // Shared routine for multiple compare operations.
 static void VisitCompare(InstructionSelector* selector, InstructionCode opcode,
                          InstructionOperand* left, InstructionOperand* right,

src/compiler/ia32/instruction-selector-ia32.cc

@@ -161,27 +161,10 @@ void InstructionSelector::VisitStore(Node* node) {
 
 // Shared routine for multiple binary operations.
 static void VisitBinop(InstructionSelector* selector, Node* node,
-                       ArchOpcode opcode) {
+                       InstructionCode opcode, FlagsContinuation* cont) {
   IA32OperandGenerator g(selector);
   Int32BinopMatcher m(node);
-  // TODO(turbofan): match complex addressing modes.
-  // TODO(turbofan): if commutative, pick the non-live-in operand as the left as
-  // this might be the last use and therefore its register can be reused.
-  if (g.CanBeImmediate(m.right().node())) {
-    selector->Emit(opcode, g.DefineSameAsFirst(node), g.Use(m.left().node()),
-                   g.UseImmediate(m.right().node()));
-  } else {
-    selector->Emit(opcode, g.DefineSameAsFirst(node),
-                   g.UseRegister(m.left().node()), g.Use(m.right().node()));
-  }
-}
-
-
-static void VisitBinopWithOverflow(InstructionSelector* selector, Node* node,
-                                   InstructionCode opcode) {
-  IA32OperandGenerator g(selector);
-  Int32BinopMatcher m(node);
-  InstructionOperand* inputs[2];
+  InstructionOperand* inputs[4];
   size_t input_count = 0;
   InstructionOperand* outputs[2];
   size_t output_count = 0;
@@ -197,19 +180,15 @@ static void VisitBinopWithOverflow(InstructionSelector* selector, Node* node,
     inputs[input_count++] = g.Use(m.right().node());
   }
 
-  // Define outputs depending on the projections.
-  Node* projections[2];
-  node->CollectProjections(ARRAY_SIZE(projections), projections);
-  if (projections[0]) {
-    outputs[output_count++] = g.DefineSameAsFirst(projections[0]);
+  if (cont->IsBranch()) {
+    inputs[input_count++] = g.Label(cont->true_block());
+    inputs[input_count++] = g.Label(cont->false_block());
   }
-  if (projections[1]) {
-    opcode |= FlagsModeField::encode(kFlags_set);
-    opcode |= FlagsConditionField::encode(kOverflow);
+
+  outputs[output_count++] = g.DefineSameAsFirst(node);
+  if (cont->IsSet()) {
     // TODO(turbofan): Use byte register here.
-    outputs[output_count++] =
-        (projections[0] ? g.DefineAsRegister(projections[1])
-                        : g.DefineSameAsFirst(projections[1]));
+    outputs[output_count++] = g.DefineAsRegister(cont->result());
   }
 
   ASSERT_NE(0, input_count);
@@ -217,7 +196,17 @@ static void VisitBinopWithOverflow(InstructionSelector* selector, Node* node,
   ASSERT_GE(ARRAY_SIZE(inputs), input_count);
   ASSERT_GE(ARRAY_SIZE(outputs), output_count);
 
-  selector->Emit(opcode, output_count, outputs, input_count, inputs);
+  Instruction* instr = selector->Emit(cont->Encode(opcode), output_count,
+                                      outputs, input_count, inputs);
+  if (cont->IsBranch()) instr->MarkAsControl();
+}
+
+
+// Shared routine for multiple binary operations.
+static void VisitBinop(InstructionSelector* selector, Node* node,
+                       InstructionCode opcode) {
+  FlagsContinuation cont;
+  VisitBinop(selector, node, opcode, &cont);
 }
 
 
@@ -287,11 +276,6 @@ void InstructionSelector::VisitInt32Add(Node* node) {
 }
 
 
-void InstructionSelector::VisitInt32AddWithOverflow(Node* node) {
-  VisitBinopWithOverflow(this, node, kIA32Add);
-}
-
-
 void InstructionSelector::VisitInt32Sub(Node* node) {
   IA32OperandGenerator g(this);
   Int32BinopMatcher m(node);
@@ -303,11 +287,6 @@ void InstructionSelector::VisitInt32Sub(Node* node) {
 }
 
 
-void InstructionSelector::VisitInt32SubWithOverflow(Node* node) {
-  VisitBinopWithOverflow(this, node, kIA32Sub);
-}
-
-
 void InstructionSelector::VisitInt32Mul(Node* node) {
   IA32OperandGenerator g(this);
   Node* left = node->InputAt(0);
@@ -438,6 +417,18 @@ void InstructionSelector::VisitFloat64Mod(Node* node) {
 }
 
 
+void InstructionSelector::VisitInt32AddWithOverflow(Node* node,
+                                                    FlagsContinuation* cont) {
+  VisitBinop(this, node, kIA32Add, cont);
+}
+
+
+void InstructionSelector::VisitInt32SubWithOverflow(Node* node,
+                                                    FlagsContinuation* cont) {
+  VisitBinop(this, node, kIA32Sub, cont);
+}
+
+
 // Shared routine for multiple compare operations.
 static inline void VisitCompare(InstructionSelector* selector,
                                 InstructionCode opcode,

src/compiler/instruction-selector-impl.h

@@ -48,6 +48,7 @@ class OperandGenerator {
   }
 
   InstructionOperand* DefineAsConstant(Node* node) {
+    selector()->MarkAsDefined(node);
     sequence()->AddConstant(node->id(), ToConstant(node));
     return ConstantOperand::Create(node->id(), zone());
   }
@@ -179,12 +180,16 @@ class OperandGenerator {
     ASSERT_NOT_NULL(node);
     ASSERT_NOT_NULL(operand);
     operand->set_virtual_register(node->id());
+    selector()->MarkAsDefined(node);
     return operand;
   }
 
   UnallocatedOperand* Use(Node* node, UnallocatedOperand* operand) {
-    selector_->MarkAsUsed(node);
-    return Define(node, operand);
+    ASSERT_NOT_NULL(node);
+    ASSERT_NOT_NULL(operand);
+    operand->set_virtual_register(node->id());
+    selector()->MarkAsUsed(node);
+    return operand;
   }
 
   UnallocatedOperand* ToUnallocatedOperand(LinkageLocation location) {
@@ -215,6 +220,8 @@ class OperandGenerator {
 // instruction and the branch or set it should be combined with.
 class FlagsContinuation V8_FINAL {
  public:
+  FlagsContinuation() : mode_(kFlags_none) {}
+
   // Creates a new flags continuation from the given condition and true/false
   // blocks.
   FlagsContinuation(FlagsCondition condition, BasicBlock* true_block,
@@ -236,7 +243,10 @@ class FlagsContinuation V8_FINAL {
   bool IsNone() const { return mode_ == kFlags_none; }
   bool IsBranch() const { return mode_ == kFlags_branch; }
   bool IsSet() const { return mode_ == kFlags_set; }
-  FlagsCondition condition() const { return condition_; }
+  FlagsCondition condition() const {
+    ASSERT(!IsNone());
+    return condition_;
+  }
   Node* result() const {
     ASSERT(IsSet());
     return result_;
@@ -250,9 +260,13 @@ class FlagsContinuation V8_FINAL {
     return false_block_;
   }
 
-  void Negate() { condition_ = static_cast<FlagsCondition>(condition_ ^ 1); }
+  void Negate() {
+    ASSERT(!IsNone());
+    condition_ = static_cast<FlagsCondition>(condition_ ^ 1);
+  }
 
   void Commute() {
+    ASSERT(!IsNone());
     switch (condition_) {
       case kEqual:
       case kNotEqual:
@@ -312,8 +326,11 @@ class FlagsContinuation V8_FINAL {
 
   // Encodes this flags continuation into the given opcode.
   InstructionCode Encode(InstructionCode opcode) {
-    return opcode | FlagsModeField::encode(mode_) |
-           FlagsConditionField::encode(condition_);
+    opcode |= FlagsModeField::encode(mode_);
+    if (mode_ != kFlags_none) {
+      opcode |= FlagsConditionField::encode(condition_);
+    }
+    return opcode;
   }
 
  private:

src/compiler/instruction-selector.cc

@@ -20,6 +20,7 @@ InstructionSelector::InstructionSelector(InstructionSequence* sequence,
       source_positions_(source_positions),
       current_block_(NULL),
       instructions_(InstructionDeque::allocator_type(zone())),
+      defined_(graph()->NodeCount(), false, BoolVector::allocator_type(zone())),
       used_(graph()->NodeCount(), false, BoolVector::allocator_type(zone())) {}
 
 
@@ -149,6 +150,24 @@ bool InstructionSelector::CanCover(Node* user, Node* node) const {
 }
 
 
+bool InstructionSelector::IsDefined(Node* node) const {
+  ASSERT_NOT_NULL(node);
+  NodeId id = node->id();
+  ASSERT(id >= 0);
+  ASSERT(id < static_cast<NodeId>(defined_.size()));
+  return defined_[id];
+}
+
+
+void InstructionSelector::MarkAsDefined(Node* node) {
+  ASSERT_NOT_NULL(node);
+  NodeId id = node->id();
+  ASSERT(id >= 0);
+  ASSERT(id < static_cast<NodeId>(defined_.size()));
+  defined_[id] = true;
+}
+
+
 bool InstructionSelector::IsUsed(Node* node) const {
   if (!node->op()->HasProperty(Operator::kEliminatable)) return true;
   NodeId id = node->id();
@@ -347,7 +366,8 @@ void InstructionSelector::VisitBlock(BasicBlock* block) {
   for (BasicBlock::reverse_iterator i = block->rbegin(); i != block->rend();
        ++i) {
     Node* node = *i;
-    if (!IsUsed(node)) continue;
+    // Skip nodes that are unused or already defined.
+    if (!IsUsed(node) || IsDefined(node)) continue;
     // Generate code for this node "top down", but schedule the code "bottom
     // up".
     size_t current_node_end = instructions_.size();
@@ -630,6 +650,26 @@ void InstructionSelector::VisitWord64Equal(Node* node) {
 }
 
 
+void InstructionSelector::VisitInt32AddWithOverflow(Node* node) {
+  if (Node* ovf = node->FindProjection(1)) {
+    FlagsContinuation cont(kOverflow, ovf);
+    return VisitInt32AddWithOverflow(node, &cont);
+  }
+  FlagsContinuation cont;
+  VisitInt32AddWithOverflow(node, &cont);
+}
+
+
+void InstructionSelector::VisitInt32SubWithOverflow(Node* node) {
+  if (Node* ovf = node->FindProjection(1)) {
+    FlagsContinuation cont(kOverflow, ovf);
+    return VisitInt32SubWithOverflow(node, &cont);
+  }
+  FlagsContinuation cont;
+  VisitInt32SubWithOverflow(node, &cont);
+}
+
+
 void InstructionSelector::VisitInt64LessThan(Node* node) {
   FlagsContinuation cont(kSignedLessThan, node);
   VisitWord64Compare(node, &cont);
@@ -748,8 +788,20 @@ void InstructionSelector::VisitPhi(Node* node) {
 
 
 void InstructionSelector::VisitProjection(Node* node) {
-  for (InputIter i = node->inputs().begin(); i != node->inputs().end(); ++i) {
-    MarkAsUsed(*i);
+  OperandGenerator g(this);
+  Node* value = node->InputAt(0);
+  switch (value->opcode()) {
+    case IrOpcode::kInt32AddWithOverflow:
+    case IrOpcode::kInt32SubWithOverflow:
+      if (OpParameter<int32_t>(node) == 0) {
+        Emit(kArchNop, g.DefineSameAsFirst(node), g.Use(value));
+      } else {
+        ASSERT_EQ(1, OpParameter<int32_t>(node));
+        MarkAsUsed(value);
+      }
+      break;
+    default:
+      break;
   }
 }
 
@@ -849,6 +901,31 @@ void InstructionSelector::VisitBranch(Node* branch, BasicBlock* tbranch,
       case IrOpcode::kFloat64LessThanOrEqual:
         cont.OverwriteAndNegateIfEqual(kUnorderedLessThanOrEqual);
         return VisitFloat64Compare(value, &cont);
+      case IrOpcode::kProjection:
+        // Check if this is the overflow output projection of an
+        // <Operation>WithOverflow node.
+        if (OpParameter<int32_t>(value) == 1) {
+          // We cannot combine the <Operation>WithOverflow with this branch
+          // unless the 0th projection (the use of the actual value of the
+          // <Operation> is either NULL, which means there's no use of the
+          // actual value, or was already defined, which means it is scheduled
+          // *AFTER* this branch).
+          Node* node = value->InputAt(0);
+          Node* result = node->FindProjection(0);
+          if (result == NULL || IsDefined(result)) {
+            switch (node->opcode()) {
+              case IrOpcode::kInt32AddWithOverflow:
+                cont.OverwriteAndNegateIfEqual(kOverflow);
+                return VisitInt32AddWithOverflow(node, &cont);
+              case IrOpcode::kInt32SubWithOverflow:
+                cont.OverwriteAndNegateIfEqual(kOverflow);
+                return VisitInt32SubWithOverflow(node, &cont);
+              default:
+                break;
+            }
+          }
+        }
+        break;
       default:
         break;
     }
@@ -885,6 +962,7 @@ void InstructionSelector::VisitDeoptimization(Node* deopt) {
   Emit(kArchDeoptimize | MiscField::encode(deoptimization_id), NULL);
 }
 
+
 #if !V8_TURBOFAN_TARGET
 
 #define DECLARE_UNIMPLEMENTED_SELECTOR(x) \
@@ -893,6 +971,18 @@ MACHINE_OP_LIST(DECLARE_UNIMPLEMENTED_SELECTOR)
 #undef DECLARE_UNIMPLEMENTED_SELECTOR
 
 
+void InstructionSelector::VisitInt32AddWithOverflow(Node* node,
+                                                    FlagsContinuation* cont) {
+  UNIMPLEMENTED();
+}
+
+
+void InstructionSelector::VisitInt32SubWithOverflow(Node* node,
+                                                    FlagsContinuation* cont) {
+  UNIMPLEMENTED();
+}
+
+
 void InstructionSelector::VisitWord32Test(Node* node, FlagsContinuation* cont) {
   UNIMPLEMENTED();
 }
@@ -913,7 +1003,7 @@ void InstructionSelector::VisitFloat64Compare(Node* node,
 void InstructionSelector::VisitCall(Node* call, BasicBlock* continuation,
                                     BasicBlock* deoptimization) {}
 
-#endif
+#endif  // !V8_TURBOFAN_TARGET
 
 }  // namespace compiler
 }  // namespace internal

src/compiler/instruction-selector.h

@@ -71,6 +71,13 @@ class InstructionSelector V8_FINAL {
   // edge and the two are in the same basic block.
   bool CanCover(Node* user, Node* node) const;
 
+  // Checks if {node} was already defined, and therefore code was already
+  // generated for it.
+  bool IsDefined(Node* node) const;
+
+  // Inform the instruction selection that {node} was just defined.
+  void MarkAsDefined(Node* node);
+
   // Checks if {node} has any uses, and therefore code has to be generated for
   // it.
   bool IsUsed(Node* node) const;
@@ -123,6 +130,9 @@ class InstructionSelector V8_FINAL {
   MACHINE_OP_LIST(DECLARE_GENERATOR)
 #undef DECLARE_GENERATOR
 
+  void VisitInt32AddWithOverflow(Node* node, FlagsContinuation* cont);
+  void VisitInt32SubWithOverflow(Node* node, FlagsContinuation* cont);
+
   void VisitWord32Test(Node* node, FlagsContinuation* cont);
   void VisitWord64Test(Node* node, FlagsContinuation* cont);
   void VisitWord32Compare(Node* node, FlagsContinuation* cont);
@@ -160,6 +170,7 @@ class InstructionSelector V8_FINAL {
   SourcePositionTable* source_positions_;
   BasicBlock* current_block_;
   Instructions instructions_;
+  BoolVector defined_;
   BoolVector used_;
 };
 

src/compiler/machine-node-factory.h

@@ -199,20 +199,14 @@ class MachineNodeFactory {
   Node* Int32Add(Node* a, Node* b) {
     return NEW_NODE_2(MACHINE()->Int32Add(), a, b);
   }
-  void Int32AddWithOverflow(Node* a, Node* b, Node** val_return,
-                            Node** ovf_return) {
-    Node* add = NEW_NODE_2(MACHINE()->Int32AddWithOverflow(), a, b);
-    if (val_return) *val_return = Projection(0, add);
-    if (ovf_return) *ovf_return = Projection(1, add);
+  Node* Int32AddWithOverflow(Node* a, Node* b) {
+    return NEW_NODE_2(MACHINE()->Int32AddWithOverflow(), a, b);
   }
   Node* Int32Sub(Node* a, Node* b) {
     return NEW_NODE_2(MACHINE()->Int32Sub(), a, b);
   }
-  void Int32SubWithOverflow(Node* a, Node* b, Node** val_return,
-                            Node** ovf_return) {
-    Node* add = NEW_NODE_2(MACHINE()->Int32SubWithOverflow(), a, b);
-    if (val_return) *val_return = Projection(0, add);
-    if (ovf_return) *ovf_return = Projection(1, add);
+  Node* Int32SubWithOverflow(Node* a, Node* b) {
+    return NEW_NODE_2(MACHINE()->Int32SubWithOverflow(), a, b);
   }
   Node* Int32Mul(Node* a, Node* b) {
     return NEW_NODE_2(MACHINE()->Int32Mul(), a, b);

src/compiler/node.cc

@@ -23,6 +23,17 @@ void Node::CollectProjections(int projection_count, Node** projections) {
 }
 
 
+Node* Node::FindProjection(int32_t projection_index) {
+  for (UseIter i = uses().begin(); i != uses().end(); ++i) {
+    if ((*i)->opcode() == IrOpcode::kProjection &&
+        OpParameter<int32_t>(*i) == projection_index) {
+      return *i;
+    }
+  }
+  return NULL;
+}
+
+
 OStream& operator<<(OStream& os, const Operator& op) { return op.PrintTo(os); }
 
 

src/compiler/node.h

@@ -55,6 +55,7 @@ class Node : public GenericNode<NodeData, Node> {
   void Initialize(Operator* op) { set_op(op); }
 
   void CollectProjections(int projection_count, Node** projections);
+  Node* FindProjection(int32_t projection_index);
 };
 
 OStream& operator<<(OStream& os, const Node& n);

src/compiler/x64/instruction-selector-x64.cc

@@ -176,31 +176,10 @@ void InstructionSelector::VisitStore(Node* node) {
 
 // Shared routine for multiple binary operations.
 static void VisitBinop(InstructionSelector* selector, Node* node,
-                       ArchOpcode opcode, bool commutative) {
-  X64OperandGenerator g(selector);
-  Node* left = node->InputAt(0);
-  Node* right = node->InputAt(1);
-  // TODO(turbofan): match complex addressing modes.
-  // TODO(turbofan): if commutative, pick the non-live-in operand as the left as
-  // this might be the last use and therefore its register can be reused.
-  if (g.CanBeImmediate(right)) {
-    selector->Emit(opcode, g.DefineSameAsFirst(node), g.Use(left),
-                   g.UseImmediate(right));
-  } else if (commutative && g.CanBeImmediate(left)) {
-    selector->Emit(opcode, g.DefineSameAsFirst(node), g.Use(right),
-                   g.UseImmediate(left));
-  } else {
-    selector->Emit(opcode, g.DefineSameAsFirst(node), g.UseRegister(left),
-                   g.Use(right));
-  }
-}
-
-
-static void VisitBinopWithOverflow(InstructionSelector* selector, Node* node,
-                                   InstructionCode opcode) {
+                       InstructionCode opcode, FlagsContinuation* cont) {
   X64OperandGenerator g(selector);
   Int32BinopMatcher m(node);
-  InstructionOperand* inputs[2];
+  InstructionOperand* inputs[4];
   size_t input_count = 0;
   InstructionOperand* outputs[2];
   size_t output_count = 0;
@@ -216,18 +195,14 @@ static void VisitBinopWithOverflow(InstructionSelector* selector, Node* node,
     inputs[input_count++] = g.Use(m.right().node());
   }
 
-  // Define outputs depending on the projections.
-  Node* projections[2];
-  node->CollectProjections(ARRAY_SIZE(projections), projections);
-  if (projections[0]) {
-    outputs[output_count++] = g.DefineSameAsFirst(projections[0]);
+  if (cont->IsBranch()) {
+    inputs[input_count++] = g.Label(cont->true_block());
+    inputs[input_count++] = g.Label(cont->false_block());
   }
-  if (projections[1]) {
-    opcode |= FlagsModeField::encode(kFlags_set);
-    opcode |= FlagsConditionField::encode(kOverflow);
-    outputs[output_count++] =
-        (projections[0] ? g.DefineAsRegister(projections[1])
-                        : g.DefineSameAsFirst(projections[1]));
+
+  outputs[output_count++] = g.DefineSameAsFirst(node);
+  if (cont->IsSet()) {
+    outputs[output_count++] = g.DefineAsRegister(cont->result());
   }
 
   ASSERT_NE(0, input_count);
@@ -235,27 +210,37 @@ static void VisitBinopWithOverflow(InstructionSelector* selector, Node* node,
   ASSERT_GE(ARRAY_SIZE(inputs), input_count);
   ASSERT_GE(ARRAY_SIZE(outputs), output_count);
 
-  selector->Emit(opcode, output_count, outputs, input_count, inputs);
+  Instruction* instr = selector->Emit(cont->Encode(opcode), output_count,
+                                      outputs, input_count, inputs);
+  if (cont->IsBranch()) instr->MarkAsControl();
+}
+
+
+// Shared routine for multiple binary operations.
+static void VisitBinop(InstructionSelector* selector, Node* node,
+                       InstructionCode opcode) {
+  FlagsContinuation cont;
+  VisitBinop(selector, node, opcode, &cont);
 }
 
 
 void InstructionSelector::VisitWord32And(Node* node) {
-  VisitBinop(this, node, kX64And32, true);
+  VisitBinop(this, node, kX64And32);
 }
 
 
 void InstructionSelector::VisitWord64And(Node* node) {
-  VisitBinop(this, node, kX64And, true);
+  VisitBinop(this, node, kX64And);
 }
 
 
 void InstructionSelector::VisitWord32Or(Node* node) {
-  VisitBinop(this, node, kX64Or32, true);
+  VisitBinop(this, node, kX64Or32);
 }
 
 
 void InstructionSelector::VisitWord64Or(Node* node) {
-  VisitBinop(this, node, kX64Or, true);
+  VisitBinop(this, node, kX64Or);
 }
 
 
@@ -268,7 +253,7 @@ static void VisitXor(InstructionSelector* selector, Node* node,
     selector->Emit(not_opcode, g.DefineSameAsFirst(node),
                    g.Use(m.left().node()));
   } else {
-    VisitBinop(selector, node, xor_opcode, true);
+    VisitBinop(selector, node, xor_opcode);
   }
 }
 
@@ -366,17 +351,12 @@ void InstructionSelector::VisitWord64Sar(Node* node) {
 
 
 void InstructionSelector::VisitInt32Add(Node* node) {
-  VisitBinop(this, node, kX64Add32, true);
-}
-
-
-void InstructionSelector::VisitInt32AddWithOverflow(Node* node) {
-  VisitBinopWithOverflow(this, node, kX64Add32);
+  VisitBinop(this, node, kX64Add32);
 }
 
 
 void InstructionSelector::VisitInt64Add(Node* node) {
-  VisitBinop(this, node, kX64Add, true);
+  VisitBinop(this, node, kX64Add);
 }
 
 
@@ -389,7 +369,7 @@ static void VisitSub(InstructionSelector* selector, Node* node,
     selector->Emit(neg_opcode, g.DefineSameAsFirst(node),
                    g.Use(m.right().node()));
   } else {
-    VisitBinop(selector, node, sub_opcode, false);
+    VisitBinop(selector, node, sub_opcode);
   }
 }
 
@@ -399,11 +379,6 @@ void InstructionSelector::VisitInt32Sub(Node* node) {
 }
 
 
-void InstructionSelector::VisitInt32SubWithOverflow(Node* node) {
-  VisitBinopWithOverflow(this, node, kX64Sub32);
-}
-
-
 void InstructionSelector::VisitInt64Sub(Node* node) {
   VisitSub<int64_t>(this, node, kX64Sub, kX64Neg);
 }
@@ -584,6 +559,18 @@ void InstructionSelector::VisitConvertInt32ToInt64(Node* node) {
 }
 
 
+void InstructionSelector::VisitInt32AddWithOverflow(Node* node,
+                                                    FlagsContinuation* cont) {
+  VisitBinop(this, node, kX64Add32, cont);
+}
+
+
+void InstructionSelector::VisitInt32SubWithOverflow(Node* node,
+                                                    FlagsContinuation* cont) {
+  VisitBinop(this, node, kX64Sub32, cont);
+}
+
+
 // Shared routine for multiple compare operations.
 static void VisitCompare(InstructionSelector* selector, InstructionCode opcode,
                          InstructionOperand* left, InstructionOperand* right,

test/cctest/compiler/test-run-machops.cc

@@ -3903,8 +3903,9 @@ TEST(RunInt32AddWithOverflowP) {
   int32_t actual_val = -1;
   RawMachineAssemblerTester<int32_t> m;
   Int32BinopTester bt(&m);
-  Node* val, *ovf;
-  m.Int32AddWithOverflow(bt.param0, bt.param1, &val, &ovf);
+  Node* add = m.Int32AddWithOverflow(bt.param0, bt.param1);
+  Node* val = m.Projection(0, add);
+  Node* ovf = m.Projection(1, add);
   m.StoreToPointer(&actual_val, kMachineWord32, val);
   bt.AddReturn(ovf);
   FOR_INT32_INPUTS(i) {
@@ -3923,8 +3924,9 @@ TEST(RunInt32AddWithOverflowImm) {
   FOR_INT32_INPUTS(i) {
     {
       RawMachineAssemblerTester<int32_t> m(kMachineWord32);
-      Node* val, *ovf;
-      m.Int32AddWithOverflow(m.Int32Constant(*i), m.Parameter(0), &val, &ovf);
+      Node* add = m.Int32AddWithOverflow(m.Int32Constant(*i), m.Parameter(0));
+      Node* val = m.Projection(0, add);
+      Node* ovf = m.Projection(1, add);
       m.StoreToPointer(&actual_val, kMachineWord32, val);
       m.Return(ovf);
       FOR_INT32_INPUTS(j) {
@@ -3935,8 +3937,9 @@ TEST(RunInt32AddWithOverflowImm) {
     }
     {
       RawMachineAssemblerTester<int32_t> m(kMachineWord32);
-      Node* val, *ovf;
-      m.Int32AddWithOverflow(m.Parameter(0), m.Int32Constant(*i), &val, &ovf);
+      Node* add = m.Int32AddWithOverflow(m.Parameter(0), m.Int32Constant(*i));
+      Node* val = m.Projection(0, add);
+      Node* ovf = m.Projection(1, add);
       m.StoreToPointer(&actual_val, kMachineWord32, val);
       m.Return(ovf);
       FOR_INT32_INPUTS(j) {
@@ -3947,9 +3950,10 @@ TEST(RunInt32AddWithOverflowImm) {
     }
     FOR_INT32_INPUTS(j) {
       RawMachineAssemblerTester<int32_t> m;
-      Node* val, *ovf;
-      m.Int32AddWithOverflow(m.Int32Constant(*i), m.Int32Constant(*j), &val,
-                             &ovf);
+      Node* add =
+          m.Int32AddWithOverflow(m.Int32Constant(*i), m.Int32Constant(*j));
+      Node* val = m.Projection(0, add);
+      Node* ovf = m.Projection(1, add);
       m.StoreToPointer(&actual_val, kMachineWord32, val);
       m.Return(ovf);
       int expected_ovf = sadd_overflow(*i, *j, &expected_val);
@@ -3961,20 +3965,22 @@ TEST(RunInt32AddWithOverflowImm) {
 
 
 TEST(RunInt32AddWithOverflowInBranchP) {
+  int constant = 911777;
   MLabel blocka, blockb;
   RawMachineAssemblerTester<int32_t> m;
   Int32BinopTester bt(&m);
-  Node* val, *ovf;
-  m.Int32AddWithOverflow(bt.param0, bt.param1, &val, &ovf);
+  Node* add = m.Int32AddWithOverflow(bt.param0, bt.param1);
+  Node* ovf = m.Projection(1, add);
   m.Branch(ovf, &blocka, &blockb);
   m.Bind(&blocka);
-  bt.AddReturn(m.Word32Not(val));
+  bt.AddReturn(m.Int32Constant(constant));
   m.Bind(&blockb);
+  Node* val = m.Projection(0, add);
   bt.AddReturn(val);
   FOR_UINT32_INPUTS(i) {
     FOR_UINT32_INPUTS(j) {
       int32_t expected;
-      if (sadd_overflow(*i, *j, &expected)) expected = ~expected;
+      if (sadd_overflow(*i, *j, &expected)) expected = constant;
       CHECK_EQ(expected, bt.call(*i, *j));
     }
   }
@@ -3985,8 +3991,9 @@ TEST(RunInt32SubWithOverflowP) {
   int32_t actual_val = -1;
   RawMachineAssemblerTester<int32_t> m;
   Int32BinopTester bt(&m);
-  Node* val, *ovf;
-  m.Int32SubWithOverflow(bt.param0, bt.param1, &val, &ovf);
+  Node* add = m.Int32SubWithOverflow(bt.param0, bt.param1);
+  Node* val = m.Projection(0, add);
+  Node* ovf = m.Projection(1, add);
   m.StoreToPointer(&actual_val, kMachineWord32, val);
   bt.AddReturn(ovf);
   FOR_INT32_INPUTS(i) {
@@ -4005,8 +4012,9 @@ TEST(RunInt32SubWithOverflowImm) {
   FOR_INT32_INPUTS(i) {
     {
       RawMachineAssemblerTester<int32_t> m(kMachineWord32);
-      Node* val, *ovf;
-      m.Int32SubWithOverflow(m.Int32Constant(*i), m.Parameter(0), &val, &ovf);
+      Node* add = m.Int32SubWithOverflow(m.Int32Constant(*i), m.Parameter(0));
+      Node* val = m.Projection(0, add);
+      Node* ovf = m.Projection(1, add);
       m.StoreToPointer(&actual_val, kMachineWord32, val);
       m.Return(ovf);
       FOR_INT32_INPUTS(j) {
@@ -4017,8 +4025,9 @@ TEST(RunInt32SubWithOverflowImm) {
     }
     {
       RawMachineAssemblerTester<int32_t> m(kMachineWord32);
-      Node* val, *ovf;
-      m.Int32SubWithOverflow(m.Parameter(0), m.Int32Constant(*i), &val, &ovf);
+      Node* add = m.Int32SubWithOverflow(m.Parameter(0), m.Int32Constant(*i));
+      Node* val = m.Projection(0, add);
+      Node* ovf = m.Projection(1, add);
       m.StoreToPointer(&actual_val, kMachineWord32, val);
       m.Return(ovf);
       FOR_INT32_INPUTS(j) {
@@ -4029,9 +4038,10 @@ TEST(RunInt32SubWithOverflowImm) {
     }
     FOR_INT32_INPUTS(j) {
       RawMachineAssemblerTester<int32_t> m;
-      Node* val, *ovf;
-      m.Int32SubWithOverflow(m.Int32Constant(*i), m.Int32Constant(*j), &val,
-                             &ovf);
+      Node* add =
+          m.Int32SubWithOverflow(m.Int32Constant(*i), m.Int32Constant(*j));
+      Node* val = m.Projection(0, add);
+      Node* ovf = m.Projection(1, add);
       m.StoreToPointer(&actual_val, kMachineWord32, val);
       m.Return(ovf);
       int expected_ovf = ssub_overflow(*i, *j, &expected_val);
@@ -4043,20 +4053,22 @@ TEST(RunInt32SubWithOverflowImm) {
 
 
 TEST(RunInt32SubWithOverflowInBranchP) {
+  int constant = 911999;
   MLabel blocka, blockb;
   RawMachineAssemblerTester<int32_t> m;
   Int32BinopTester bt(&m);
-  Node* val, *ovf;
-  m.Int32SubWithOverflow(bt.param0, bt.param1, &val, &ovf);
+  Node* sub = m.Int32SubWithOverflow(bt.param0, bt.param1);
+  Node* ovf = m.Projection(1, sub);
   m.Branch(ovf, &blocka, &blockb);
   m.Bind(&blocka);
-  bt.AddReturn(m.Word32Not(val));
+  bt.AddReturn(m.Int32Constant(constant));
   m.Bind(&blockb);
+  Node* val = m.Projection(0, sub);
   bt.AddReturn(val);
   FOR_UINT32_INPUTS(i) {
     FOR_UINT32_INPUTS(j) {
       int32_t expected;
-      if (ssub_overflow(*i, *j, &expected)) expected = ~expected;
+      if (ssub_overflow(*i, *j, &expected)) expected = constant;
       CHECK_EQ(expected, bt.call(*i, *j));
     }
   }