From 4ee7a92d834da3c3986c746242f320155edaa154 Mon Sep 17 00:00:00 2001
From: "olivf@chromium.org"
 <olivf@chromium.org@ce2b1a6d-e550-0410-aec6-3dcde31c8c00>
Date: Thu, 20 Jun 2013 11:50:50 +0000
Subject: [PATCH] Lithium codegen should not pass around block_ids. Rather
 encapsulate the basic block to assembly label mapping in the LInstruction.

BUG=
R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/17276002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15235 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
---
 src/arm/lithium-arm.h            |  41 ++++++++---
 src/arm/lithium-codegen-arm.cc   | 145 +++++++++++++-------------------------
 src/arm/lithium-codegen-arm.h    |   4 +-
 src/ia32/lithium-codegen-ia32.cc | 146 +++++++++++++--------------------------
 src/ia32/lithium-codegen-ia32.h  |   4 +-
 src/ia32/lithium-ia32.h          |  41 ++++++++---
 src/x64/lithium-codegen-x64.cc   | 143 +++++++++++++-------------------------
 src/x64/lithium-codegen-x64.h    |   4 +-
 src/x64/lithium-x64.h            |  41 ++++++++---
 9 files changed, 241 insertions(+), 328 deletions(-)

diff --git a/src/arm/lithium-arm.h b/src/arm/lithium-arm.h
index a3aea08..d3695b9 100644
--- a/src/arm/lithium-arm.h
+++ b/src/arm/lithium-arm.h
@@ -490,17 +490,44 @@ class LUnknownOSRValue: public LTemplateInstruction<1, 0, 0> {
 template<int I, int T>
 class LControlInstruction: public LTemplateInstruction<0, I, T> {
  public:
+  LControlInstruction() : false_label_(NULL), true_label_(NULL) { }
+
   virtual bool IsControl() const { return true; }
 
   int SuccessorCount() { return hydrogen()->SuccessorCount(); }
   HBasicBlock* SuccessorAt(int i) { return hydrogen()->SuccessorAt(i); }
-  int true_block_id() { return hydrogen()->SuccessorAt(0)->block_id(); }
-  int false_block_id() { return hydrogen()->SuccessorAt(1)->block_id(); }
+
+  int TrueDestination(LChunk* chunk) {
+    return chunk->LookupDestination(true_block_id());
+  }
+  int FalseDestination(LChunk* chunk) {
+    return chunk->LookupDestination(false_block_id());
+  }
+
+  Label* TrueLabel(LChunk* chunk) {
+    if (true_label_ == NULL) {
+      true_label_ = chunk->GetAssemblyLabel(TrueDestination(chunk));
+    }
+    return true_label_;
+  }
+  Label* FalseLabel(LChunk* chunk) {
+    if (false_label_ == NULL) {
+      false_label_ = chunk->GetAssemblyLabel(FalseDestination(chunk));
+    }
+    return false_label_;
+  }
+
+ protected:
+  int true_block_id() { return SuccessorAt(0)->block_id(); }
+  int false_block_id() { return SuccessorAt(1)->block_id(); }
 
  private:
   HControlInstruction* hydrogen() {
     return HControlInstruction::cast(this->hydrogen_value());
   }
+
+  Label* false_label_;
+  Label* true_label_;
 };
 
 
@@ -1237,7 +1264,7 @@ class LBranch: public LControlInstruction<1, 0> {
 };
 
 
-class LCmpMapAndBranch: public LTemplateInstruction<0, 1, 1> {
+class LCmpMapAndBranch: public LControlInstruction<1, 1> {
  public:
   LCmpMapAndBranch(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -1250,15 +1277,7 @@ class LCmpMapAndBranch: public LTemplateInstruction<0, 1, 1> {
   DECLARE_CONCRETE_INSTRUCTION(CmpMapAndBranch, "cmp-map-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(CompareMap)
 
-  virtual bool IsControl() const { return true; }
-
   Handle<Map> map() const { return hydrogen()->map(); }
-  int true_block_id() const {
-    return hydrogen()->FirstSuccessor()->block_id();
-  }
-  int false_block_id() const {
-    return hydrogen()->SecondSuccessor()->block_id();
-  }
 };
 
 
diff --git a/src/arm/lithium-codegen-arm.cc b/src/arm/lithium-codegen-arm.cc
index b5ed662..431bb38 100644
--- a/src/arm/lithium-codegen-arm.cc
+++ b/src/arm/lithium-codegen-arm.cc
@@ -2159,11 +2159,12 @@ int LCodeGen::GetNextEmittedBlock() const {
   return -1;
 }
 
+template<class InstrType>
+void LCodeGen::EmitBranch(InstrType instr, Condition cc) {
+  int right_block = instr->FalseDestination(chunk_);
+  int left_block = instr->TrueDestination(chunk_);
 
-void LCodeGen::EmitBranch(int left_block, int right_block, Condition cc) {
   int next_block = GetNextEmittedBlock();
-  right_block = chunk_->LookupDestination(right_block);
-  left_block = chunk_->LookupDestination(left_block);
 
   if (right_block == left_block) {
     EmitGoto(left_block);
@@ -2184,22 +2185,19 @@ void LCodeGen::DoDebugBreak(LDebugBreak* instr) {
 
 
 void LCodeGen::DoBranch(LBranch* instr) {
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-
   Representation r = instr->hydrogen()->value()->representation();
   if (r.IsInteger32() || r.IsSmi()) {
     ASSERT(!info()->IsStub());
     Register reg = ToRegister(instr->value());
     __ cmp(reg, Operand::Zero());
-    EmitBranch(true_block, false_block, ne);
+    EmitBranch(instr, ne);
   } else if (r.IsDouble()) {
     ASSERT(!info()->IsStub());
     DwVfpRegister reg = ToDoubleRegister(instr->value());
     // Test the double value. Zero and NaN are false.
     __ VFPCompareAndSetFlags(reg, 0.0);
     __ cmp(r0, r0, vs);  // If NaN, set the Z flag.
-    EmitBranch(true_block, false_block, ne);
+    EmitBranch(instr, ne);
   } else {
     ASSERT(r.IsTagged());
     Register reg = ToRegister(instr->value());
@@ -2207,15 +2205,12 @@ void LCodeGen::DoBranch(LBranch* instr) {
     if (type.IsBoolean()) {
       ASSERT(!info()->IsStub());
       __ CompareRoot(reg, Heap::kTrueValueRootIndex);
-      EmitBranch(true_block, false_block, eq);
+      EmitBranch(instr, eq);
     } else if (type.IsSmi()) {
       ASSERT(!info()->IsStub());
       __ cmp(reg, Operand::Zero());
-      EmitBranch(true_block, false_block, ne);
+      EmitBranch(instr, ne);
     } else {
-      Label* true_label = chunk_->GetAssemblyLabel(true_block);
-      Label* false_label = chunk_->GetAssemblyLabel(false_block);
-
       ToBooleanStub::Types expected = instr->hydrogen()->expected_input_types();
       // Avoid deopts in the case where we've never executed this path before.
       if (expected.IsEmpty()) expected = ToBooleanStub::all_types();
@@ -2223,26 +2218,26 @@ void LCodeGen::DoBranch(LBranch* instr) {
       if (expected.Contains(ToBooleanStub::UNDEFINED)) {
         // undefined -> false.
         __ CompareRoot(reg, Heap::kUndefinedValueRootIndex);
-        __ b(eq, false_label);
+        __ b(eq, instr->FalseLabel(chunk_));
       }
       if (expected.Contains(ToBooleanStub::BOOLEAN)) {
         // Boolean -> its value.
         __ CompareRoot(reg, Heap::kTrueValueRootIndex);
-        __ b(eq, true_label);
+        __ b(eq, instr->TrueLabel(chunk_));
         __ CompareRoot(reg, Heap::kFalseValueRootIndex);
-        __ b(eq, false_label);
+        __ b(eq, instr->FalseLabel(chunk_));
       }
       if (expected.Contains(ToBooleanStub::NULL_TYPE)) {
         // 'null' -> false.
         __ CompareRoot(reg, Heap::kNullValueRootIndex);
-        __ b(eq, false_label);
+        __ b(eq, instr->FalseLabel(chunk_));
       }
 
       if (expected.Contains(ToBooleanStub::SMI)) {
         // Smis: 0 -> false, all other -> true.
         __ cmp(reg, Operand::Zero());
-        __ b(eq, false_label);
-        __ JumpIfSmi(reg, true_label);
+        __ b(eq, instr->FalseLabel(chunk_));
+        __ JumpIfSmi(reg, instr->TrueLabel(chunk_));
       } else if (expected.NeedsMap()) {
         // If we need a map later and have a Smi -> deopt.
         __ SmiTst(reg);
@@ -2257,14 +2252,14 @@ void LCodeGen::DoBranch(LBranch* instr) {
           // Undetectable -> false.
           __ ldrb(ip, FieldMemOperand(map, Map::kBitFieldOffset));
           __ tst(ip, Operand(1 << Map::kIsUndetectable));
-          __ b(ne, false_label);
+          __ b(ne, instr->FalseLabel(chunk_));
         }
       }
 
       if (expected.Contains(ToBooleanStub::SPEC_OBJECT)) {
         // spec object -> true.
         __ CompareInstanceType(map, ip, FIRST_SPEC_OBJECT_TYPE);
-        __ b(ge, true_label);
+        __ b(ge, instr->TrueLabel(chunk_));
       }
 
       if (expected.Contains(ToBooleanStub::STRING)) {
@@ -2274,15 +2269,15 @@ void LCodeGen::DoBranch(LBranch* instr) {
         __ b(ge, &not_string);
         __ ldr(ip, FieldMemOperand(reg, String::kLengthOffset));
         __ cmp(ip, Operand::Zero());
-        __ b(ne, true_label);
-        __ b(false_label);
+        __ b(ne, instr->TrueLabel(chunk_));
+        __ b(instr->FalseLabel(chunk_));
         __ bind(&not_string);
       }
 
       if (expected.Contains(ToBooleanStub::SYMBOL)) {
         // Symbol value -> true.
         __ CompareInstanceType(map, ip, SYMBOL_TYPE);
-        __ b(eq, true_label);
+        __ b(eq, instr->TrueLabel(chunk_));
       }
 
       if (expected.Contains(ToBooleanStub::HEAP_NUMBER)) {
@@ -2294,8 +2289,8 @@ void LCodeGen::DoBranch(LBranch* instr) {
         __ vldr(dbl_scratch, FieldMemOperand(reg, HeapNumber::kValueOffset));
         __ VFPCompareAndSetFlags(dbl_scratch, 0.0);
         __ cmp(r0, r0, vs);  // NaN -> false.
-        __ b(eq, false_label);  // +0, -0 -> false.
-        __ b(true_label);
+        __ b(eq, instr->FalseLabel(chunk_));  // +0, -0 -> false.
+        __ b(instr->TrueLabel(chunk_));
         __ bind(&not_heap_number);
       }
 
@@ -2308,7 +2303,7 @@ void LCodeGen::DoBranch(LBranch* instr) {
 
 void LCodeGen::EmitGoto(int block) {
   if (!IsNextEmittedBlock(block)) {
-    __ jmp(chunk_->GetAssemblyLabel(chunk_->LookupDestination(block)));
+    __ jmp(chunk_->GetAssemblyLabel(LookupDestination(block)));
   }
 }
 
@@ -2349,17 +2344,14 @@ Condition LCodeGen::TokenToCondition(Token::Value op, bool is_unsigned) {
 void LCodeGen::DoCmpIDAndBranch(LCmpIDAndBranch* instr) {
   LOperand* left = instr->left();
   LOperand* right = instr->right();
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
   Condition cond = TokenToCondition(instr->op(), false);
 
   if (left->IsConstantOperand() && right->IsConstantOperand()) {
     // We can statically evaluate the comparison.
     double left_val = ToDouble(LConstantOperand::cast(left));
     double right_val = ToDouble(LConstantOperand::cast(right));
-    int next_block =
-      EvalComparison(instr->op(), left_val, right_val) ? true_block
-                                                       : false_block;
+    int next_block = EvalComparison(instr->op(), left_val, right_val) ?
+        instr->TrueDestination(chunk_) : instr->FalseDestination(chunk_);
     EmitGoto(next_block);
   } else {
     if (instr->is_double()) {
@@ -2368,7 +2360,7 @@ void LCodeGen::DoCmpIDAndBranch(LCmpIDAndBranch* instr) {
       __ VFPCompareAndSetFlags(ToDoubleRegister(left), ToDoubleRegister(right));
       // If a NaN is involved, i.e. the result is unordered (V set),
       // jump to false block label.
-      __ b(vs, chunk_->GetAssemblyLabel(false_block));
+      __ b(vs, instr->FalseLabel(chunk_));
     } else {
       if (right->IsConstantOperand()) {
         int32_t value = ToInteger32(LConstantOperand::cast(right));
@@ -2390,7 +2382,7 @@ void LCodeGen::DoCmpIDAndBranch(LCmpIDAndBranch* instr) {
         __ cmp(ToRegister(left), ToRegister(right));
       }
     }
-    EmitBranch(true_block, false_block, cond);
+    EmitBranch(instr, cond);
   }
 }
 
@@ -2398,21 +2390,17 @@ void LCodeGen::DoCmpIDAndBranch(LCmpIDAndBranch* instr) {
 void LCodeGen::DoCmpObjectEqAndBranch(LCmpObjectEqAndBranch* instr) {
   Register left = ToRegister(instr->left());
   Register right = ToRegister(instr->right());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
 
   __ cmp(left, Operand(right));
-  EmitBranch(true_block, false_block, eq);
+  EmitBranch(instr, eq);
 }
 
 
 void LCodeGen::DoCmpConstantEqAndBranch(LCmpConstantEqAndBranch* instr) {
   Register left = ToRegister(instr->left());
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
 
   __ cmp(left, Operand(instr->hydrogen()->right()));
-  EmitBranch(true_block, false_block, eq);
+  EmitBranch(instr, eq);
 }
 
 
@@ -2447,15 +2435,11 @@ void LCodeGen::DoIsObjectAndBranch(LIsObjectAndBranch* instr) {
   Register reg = ToRegister(instr->value());
   Register temp1 = ToRegister(instr->temp());
 
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-  Label* true_label = chunk_->GetAssemblyLabel(true_block);
-  Label* false_label = chunk_->GetAssemblyLabel(false_block);
-
   Condition true_cond =
-      EmitIsObject(reg, temp1, false_label, true_label);
+      EmitIsObject(reg, temp1,
+          instr->FalseLabel(chunk_), instr->TrueLabel(chunk_));
 
-  EmitBranch(true_block, false_block, true_cond);
+  EmitBranch(instr, true_cond);
 }
 
 
@@ -2473,24 +2457,17 @@ void LCodeGen::DoIsStringAndBranch(LIsStringAndBranch* instr) {
   Register reg = ToRegister(instr->value());
   Register temp1 = ToRegister(instr->temp());
 
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-  Label* false_label = chunk_->GetAssemblyLabel(false_block);
-
   Condition true_cond =
-      EmitIsString(reg, temp1, false_label);
+      EmitIsString(reg, temp1, instr->FalseLabel(chunk_));
 
-  EmitBranch(true_block, false_block, true_cond);
+  EmitBranch(instr, true_cond);
 }
 
 
 void LCodeGen::DoIsSmiAndBranch(LIsSmiAndBranch* instr) {
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-
   Register input_reg = EmitLoadRegister(instr->value(), ip);
   __ SmiTst(input_reg);
-  EmitBranch(true_block, false_block, eq);
+  EmitBranch(instr, eq);
 }
 
 
@@ -2498,14 +2475,11 @@ void LCodeGen::DoIsUndetectableAndBranch(LIsUndetectableAndBranch* instr) {
   Register input = ToRegister(instr->value());
   Register temp = ToRegister(instr->temp());
 
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-
-  __ JumpIfSmi(input, chunk_->GetAssemblyLabel(false_block));
+  __ JumpIfSmi(input, instr->FalseLabel(chunk_));
   __ ldr(temp, FieldMemOperand(input, HeapObject::kMapOffset));
   __ ldrb(temp, FieldMemOperand(temp, Map::kBitFieldOffset));
   __ tst(temp, Operand(1 << Map::kIsUndetectable));
-  EmitBranch(true_block, false_block, ne);
+  EmitBranch(instr, ne);
 }
 
 
@@ -2531,8 +2505,6 @@ static Condition ComputeCompareCondition(Token::Value op) {
 
 void LCodeGen::DoStringCompareAndBranch(LStringCompareAndBranch* instr) {
   Token::Value op = instr->op();
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
 
   Handle<Code> ic = CompareIC::GetUninitialized(isolate(), op);
   CallCode(ic, RelocInfo::CODE_TARGET, instr);
@@ -2541,7 +2513,7 @@ void LCodeGen::DoStringCompareAndBranch(LStringCompareAndBranch* instr) {
 
   Condition condition = ComputeCompareCondition(op);
 
-  EmitBranch(true_block, false_block, condition);
+  EmitBranch(instr, condition);
 }
 
 
@@ -2569,15 +2541,10 @@ void LCodeGen::DoHasInstanceTypeAndBranch(LHasInstanceTypeAndBranch* instr) {
   Register scratch = scratch0();
   Register input = ToRegister(instr->value());
 
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-
-  Label* false_label = chunk_->GetAssemblyLabel(false_block);
-
-  __ JumpIfSmi(input, false_label);
+  __ JumpIfSmi(input, instr->FalseLabel(chunk_));
 
   __ CompareObjectType(input, scratch, scratch, TestType(instr->hydrogen()));
-  EmitBranch(true_block, false_block, BranchCondition(instr->hydrogen()));
+  EmitBranch(instr, BranchCondition(instr->hydrogen()));
 }
 
 
@@ -2597,13 +2564,10 @@ void LCodeGen::DoHasCachedArrayIndexAndBranch(
   Register input = ToRegister(instr->value());
   Register scratch = scratch0();
 
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-
   __ ldr(scratch,
          FieldMemOperand(input, String::kHashFieldOffset));
   __ tst(scratch, Operand(String::kContainsCachedArrayIndexMask));
-  EmitBranch(true_block, false_block, eq);
+  EmitBranch(instr, eq);
 }
 
 
@@ -2680,27 +2644,20 @@ void LCodeGen::DoClassOfTestAndBranch(LClassOfTestAndBranch* instr) {
   Register temp2 = ToRegister(instr->temp());
   Handle<String> class_name = instr->hydrogen()->class_name();
 
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-
-  Label* true_label = chunk_->GetAssemblyLabel(true_block);
-  Label* false_label = chunk_->GetAssemblyLabel(false_block);
-
-  EmitClassOfTest(true_label, false_label, class_name, input, temp, temp2);
+  EmitClassOfTest(instr->TrueLabel(chunk_), instr->FalseLabel(chunk_),
+      class_name, input, temp, temp2);
 
-  EmitBranch(true_block, false_block, eq);
+  EmitBranch(instr, eq);
 }
 
 
 void LCodeGen::DoCmpMapAndBranch(LCmpMapAndBranch* instr) {
   Register reg = ToRegister(instr->value());
   Register temp = ToRegister(instr->temp());
-  int true_block = instr->true_block_id();
-  int false_block = instr->false_block_id();
 
   __ ldr(temp, FieldMemOperand(reg, HeapObject::kMapOffset));
   __ cmp(temp, Operand(instr->map()));
-  EmitBranch(true_block, false_block, eq);
+  EmitBranch(instr, eq);
 }
 
 
@@ -5597,17 +5554,13 @@ void LCodeGen::DoTypeof(LTypeof* instr) {
 
 void LCodeGen::DoTypeofIsAndBranch(LTypeofIsAndBranch* instr) {
   Register input = ToRegister(instr->value());
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-  Label* true_label = chunk_->GetAssemblyLabel(true_block);
-  Label* false_label = chunk_->GetAssemblyLabel(false_block);
 
-  Condition final_branch_condition = EmitTypeofIs(true_label,
-                                                  false_label,
+  Condition final_branch_condition = EmitTypeofIs(instr->TrueLabel(chunk_),
+                                                  instr->FalseLabel(chunk_),
                                                   input,
                                                   instr->type_literal());
   if (final_branch_condition != kNoCondition) {
-    EmitBranch(true_block, false_block, final_branch_condition);
+    EmitBranch(instr, final_branch_condition);
   }
 }
 
@@ -5692,11 +5645,9 @@ Condition LCodeGen::EmitTypeofIs(Label* true_label,
 
 void LCodeGen::DoIsConstructCallAndBranch(LIsConstructCallAndBranch* instr) {
   Register temp1 = ToRegister(instr->temp());
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
 
   EmitIsConstructCall(temp1, scratch0());
-  EmitBranch(true_block, false_block, eq);
+  EmitBranch(instr, eq);
 }
 
 
diff --git a/src/arm/lithium-codegen-arm.h b/src/arm/lithium-codegen-arm.h
index 3bdf6b0..9202dd5 100644
--- a/src/arm/lithium-codegen-arm.h
+++ b/src/arm/lithium-codegen-arm.h
@@ -79,7 +79,6 @@ class LCodeGen BASE_EMBEDDED {
   Heap* heap() const { return isolate()->heap(); }
   Zone* zone() const { return zone_; }
 
-  // TODO(svenpanne) Use this consistently.
   int LookupDestination(int block_id) const {
     return chunk()->LookupDestination(block_id);
   }
@@ -320,7 +319,8 @@ class LCodeGen BASE_EMBEDDED {
 
   static Condition TokenToCondition(Token::Value op, bool is_unsigned);
   void EmitGoto(int block);
-  void EmitBranch(int left_block, int right_block, Condition cc);
+  template<class InstrType>
+  void EmitBranch(InstrType instr, Condition cc);
   void EmitNumberUntagD(Register input,
                         DwVfpRegister result,
                         bool allow_undefined_as_nan,
diff --git a/src/ia32/lithium-codegen-ia32.cc b/src/ia32/lithium-codegen-ia32.cc
index 07e355f..28164c7 100644
--- a/src/ia32/lithium-codegen-ia32.cc
+++ b/src/ia32/lithium-codegen-ia32.cc
@@ -2087,10 +2087,12 @@ int LCodeGen::GetNextEmittedBlock() const {
 }
 
 
-void LCodeGen::EmitBranch(int left_block, int right_block, Condition cc) {
+template<class InstrType>
+void LCodeGen::EmitBranch(InstrType instr, Condition cc) {
+  int right_block = instr->FalseDestination(chunk_);
+  int left_block = instr->TrueDestination(chunk_);
+
   int next_block = GetNextEmittedBlock();
-  right_block = chunk_->LookupDestination(right_block);
-  left_block = chunk_->LookupDestination(left_block);
 
   if (right_block == left_block) {
     EmitGoto(left_block);
@@ -2106,22 +2108,19 @@ void LCodeGen::EmitBranch(int left_block, int right_block, Condition cc) {
 
 
 void LCodeGen::DoBranch(LBranch* instr) {
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-
   Representation r = instr->hydrogen()->value()->representation();
   if (r.IsSmiOrInteger32()) {
     ASSERT(!info()->IsStub());
     Register reg = ToRegister(instr->value());
     __ test(reg, Operand(reg));
-    EmitBranch(true_block, false_block, not_zero);
+    EmitBranch(instr, not_zero);
   } else if (r.IsDouble()) {
     ASSERT(!info()->IsStub());
     CpuFeatureScope scope(masm(), SSE2);
     XMMRegister reg = ToDoubleRegister(instr->value());
     __ xorps(xmm0, xmm0);
     __ ucomisd(reg, xmm0);
-    EmitBranch(true_block, false_block, not_equal);
+    EmitBranch(instr, not_equal);
   } else {
     ASSERT(r.IsTagged());
     Register reg = ToRegister(instr->value());
@@ -2129,15 +2128,12 @@ void LCodeGen::DoBranch(LBranch* instr) {
     if (type.IsBoolean()) {
       ASSERT(!info()->IsStub());
       __ cmp(reg, factory()->true_value());
-      EmitBranch(true_block, false_block, equal);
+      EmitBranch(instr, equal);
     } else if (type.IsSmi()) {
       ASSERT(!info()->IsStub());
       __ test(reg, Operand(reg));
-      EmitBranch(true_block, false_block, not_equal);
+      EmitBranch(instr, not_equal);
     } else {
-      Label* true_label = chunk_->GetAssemblyLabel(true_block);
-      Label* false_label = chunk_->GetAssemblyLabel(false_block);
-
       ToBooleanStub::Types expected = instr->hydrogen()->expected_input_types();
       // Avoid deopts in the case where we've never executed this path before.
       if (expected.IsEmpty()) expected = ToBooleanStub::all_types();
@@ -2145,27 +2141,27 @@ void LCodeGen::DoBranch(LBranch* instr) {
       if (expected.Contains(ToBooleanStub::UNDEFINED)) {
         // undefined -> false.
         __ cmp(reg, factory()->undefined_value());
-        __ j(equal, false_label);
+        __ j(equal, instr->FalseLabel(chunk_));
       }
       if (expected.Contains(ToBooleanStub::BOOLEAN)) {
         // true -> true.
         __ cmp(reg, factory()->true_value());
-        __ j(equal, true_label);
+        __ j(equal, instr->TrueLabel(chunk_));
         // false -> false.
         __ cmp(reg, factory()->false_value());
-        __ j(equal, false_label);
+        __ j(equal, instr->FalseLabel(chunk_));
       }
       if (expected.Contains(ToBooleanStub::NULL_TYPE)) {
         // 'null' -> false.
         __ cmp(reg, factory()->null_value());
-        __ j(equal, false_label);
+        __ j(equal, instr->FalseLabel(chunk_));
       }
 
       if (expected.Contains(ToBooleanStub::SMI)) {
         // Smis: 0 -> false, all other -> true.
         __ test(reg, Operand(reg));
-        __ j(equal, false_label);
-        __ JumpIfSmi(reg, true_label);
+        __ j(equal, instr->FalseLabel(chunk_));
+        __ JumpIfSmi(reg, instr->TrueLabel(chunk_));
       } else if (expected.NeedsMap()) {
         // If we need a map later and have a Smi -> deopt.
         __ test(reg, Immediate(kSmiTagMask));
@@ -2182,14 +2178,14 @@ void LCodeGen::DoBranch(LBranch* instr) {
           // Undetectable -> false.
           __ test_b(FieldOperand(map, Map::kBitFieldOffset),
                     1 << Map::kIsUndetectable);
-          __ j(not_zero, false_label);
+          __ j(not_zero, instr->FalseLabel(chunk_));
         }
       }
 
       if (expected.Contains(ToBooleanStub::SPEC_OBJECT)) {
         // spec object -> true.
         __ CmpInstanceType(map, FIRST_SPEC_OBJECT_TYPE);
-        __ j(above_equal, true_label);
+        __ j(above_equal, instr->TrueLabel(chunk_));
       }
 
       if (expected.Contains(ToBooleanStub::STRING)) {
@@ -2198,15 +2194,15 @@ void LCodeGen::DoBranch(LBranch* instr) {
         __ CmpInstanceType(map, FIRST_NONSTRING_TYPE);
         __ j(above_equal, &not_string, Label::kNear);
         __ cmp(FieldOperand(reg, String::kLengthOffset), Immediate(0));
-        __ j(not_zero, true_label);
-        __ jmp(false_label);
+        __ j(not_zero, instr->TrueLabel(chunk_));
+        __ jmp(instr->FalseLabel(chunk_));
         __ bind(&not_string);
       }
 
       if (expected.Contains(ToBooleanStub::SYMBOL)) {
         // Symbol value -> true.
         __ CmpInstanceType(map, SYMBOL_TYPE);
-        __ j(equal, true_label);
+        __ j(equal, instr->TrueLabel(chunk_));
       }
 
       if (expected.Contains(ToBooleanStub::HEAP_NUMBER)) {
@@ -2224,8 +2220,8 @@ void LCodeGen::DoBranch(LBranch* instr) {
           __ fld_d(FieldOperand(reg, HeapNumber::kValueOffset));
           __ FCmp();
         }
-        __ j(zero, false_label);
-        __ jmp(true_label);
+        __ j(zero, instr->FalseLabel(chunk_));
+        __ jmp(instr->TrueLabel(chunk_));
         __ bind(&not_heap_number);
       }
 
@@ -2238,7 +2234,7 @@ void LCodeGen::DoBranch(LBranch* instr) {
 
 void LCodeGen::EmitGoto(int block) {
   if (!IsNextEmittedBlock(block)) {
-    __ jmp(chunk_->GetAssemblyLabel(chunk_->LookupDestination(block)));
+    __ jmp(chunk_->GetAssemblyLabel(LookupDestination(block)));
   }
 }
 
@@ -2279,17 +2275,14 @@ Condition LCodeGen::TokenToCondition(Token::Value op, bool is_unsigned) {
 void LCodeGen::DoCmpIDAndBranch(LCmpIDAndBranch* instr) {
   LOperand* left = instr->left();
   LOperand* right = instr->right();
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
   Condition cc = TokenToCondition(instr->op(), instr->is_double());
 
   if (left->IsConstantOperand() && right->IsConstantOperand()) {
     // We can statically evaluate the comparison.
     double left_val = ToDouble(LConstantOperand::cast(left));
     double right_val = ToDouble(LConstantOperand::cast(right));
-    int next_block =
-      EvalComparison(instr->op(), left_val, right_val) ? true_block
-                                                       : false_block;
+    int next_block = EvalComparison(instr->op(), left_val, right_val) ?
+        instr->TrueDestination(chunk_) : instr->FalseDestination(chunk_);
     EmitGoto(next_block);
   } else {
     if (instr->is_double()) {
@@ -2297,7 +2290,7 @@ void LCodeGen::DoCmpIDAndBranch(LCmpIDAndBranch* instr) {
       // Don't base result on EFLAGS when a NaN is involved. Instead
       // jump to the false block.
       __ ucomisd(ToDoubleRegister(left), ToDoubleRegister(right));
-      __ j(parity_even, chunk_->GetAssemblyLabel(false_block));
+      __ j(parity_even, instr->FalseLabel(chunk_));
     } else {
       if (right->IsConstantOperand()) {
         int32_t const_value = ToInteger32(LConstantOperand::cast(right));
@@ -2319,15 +2312,13 @@ void LCodeGen::DoCmpIDAndBranch(LCmpIDAndBranch* instr) {
         __ cmp(ToRegister(left), ToOperand(right));
       }
     }
-    EmitBranch(true_block, false_block, cc);
+    EmitBranch(instr, cc);
   }
 }
 
 
 void LCodeGen::DoCmpObjectEqAndBranch(LCmpObjectEqAndBranch* instr) {
   Register left = ToRegister(instr->left());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
 
   if (instr->right()->IsConstantOperand()) {
     Handle<Object> right = ToHandle(LConstantOperand::cast(instr->right()));
@@ -2336,17 +2327,15 @@ void LCodeGen::DoCmpObjectEqAndBranch(LCmpObjectEqAndBranch* instr) {
     Operand right = ToOperand(instr->right());
     __ cmp(left, right);
   }
-  EmitBranch(true_block, false_block, equal);
+  EmitBranch(instr, equal);
 }
 
 
 void LCodeGen::DoCmpConstantEqAndBranch(LCmpConstantEqAndBranch* instr) {
   Register left = ToRegister(instr->left());
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
 
   __ cmp(left, instr->hydrogen()->right());
-  EmitBranch(true_block, false_block, equal);
+  EmitBranch(instr, equal);
 }
 
 
@@ -2377,14 +2366,10 @@ void LCodeGen::DoIsObjectAndBranch(LIsObjectAndBranch* instr) {
   Register reg = ToRegister(instr->value());
   Register temp = ToRegister(instr->temp());
 
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-  Label* true_label = chunk_->GetAssemblyLabel(true_block);
-  Label* false_label = chunk_->GetAssemblyLabel(false_block);
-
-  Condition true_cond = EmitIsObject(reg, temp, false_label, true_label);
+  Condition true_cond = EmitIsObject(
+      reg, temp, instr->FalseLabel(chunk_), instr->TrueLabel(chunk_));
 
-  EmitBranch(true_block, false_block, true_cond);
+  EmitBranch(instr, true_cond);
 }
 
 
@@ -2403,24 +2388,17 @@ void LCodeGen::DoIsStringAndBranch(LIsStringAndBranch* instr) {
   Register reg = ToRegister(instr->value());
   Register temp = ToRegister(instr->temp());
 
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-  Label* false_label = chunk_->GetAssemblyLabel(false_block);
+  Condition true_cond = EmitIsString(reg, temp, instr->FalseLabel(chunk_));
 
-  Condition true_cond = EmitIsString(reg, temp, false_label);
-
-  EmitBranch(true_block, false_block, true_cond);
+  EmitBranch(instr, true_cond);
 }
 
 
 void LCodeGen::DoIsSmiAndBranch(LIsSmiAndBranch* instr) {
   Operand input = ToOperand(instr->value());
 
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-
   __ test(input, Immediate(kSmiTagMask));
-  EmitBranch(true_block, false_block, zero);
+  EmitBranch(instr, zero);
 }
 
 
@@ -2428,15 +2406,12 @@ void LCodeGen::DoIsUndetectableAndBranch(LIsUndetectableAndBranch* instr) {
   Register input = ToRegister(instr->value());
   Register temp = ToRegister(instr->temp());
 
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-
   STATIC_ASSERT(kSmiTag == 0);
-  __ JumpIfSmi(input, chunk_->GetAssemblyLabel(false_block));
+  __ JumpIfSmi(input, instr->FalseLabel(chunk_));
   __ mov(temp, FieldOperand(input, HeapObject::kMapOffset));
   __ test_b(FieldOperand(temp, Map::kBitFieldOffset),
             1 << Map::kIsUndetectable);
-  EmitBranch(true_block, false_block, not_zero);
+  EmitBranch(instr, not_zero);
 }
 
 
@@ -2462,8 +2437,6 @@ static Condition ComputeCompareCondition(Token::Value op) {
 
 void LCodeGen::DoStringCompareAndBranch(LStringCompareAndBranch* instr) {
   Token::Value op = instr->op();
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
 
   Handle<Code> ic = CompareIC::GetUninitialized(isolate(), op);
   CallCode(ic, RelocInfo::CODE_TARGET, instr);
@@ -2471,7 +2444,7 @@ void LCodeGen::DoStringCompareAndBranch(LStringCompareAndBranch* instr) {
   Condition condition = ComputeCompareCondition(op);
   __ test(eax, Operand(eax));
 
-  EmitBranch(true_block, false_block, condition);
+  EmitBranch(instr, condition);
 }
 
 
@@ -2499,15 +2472,10 @@ void LCodeGen::DoHasInstanceTypeAndBranch(LHasInstanceTypeAndBranch* instr) {
   Register input = ToRegister(instr->value());
   Register temp = ToRegister(instr->temp());
 
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-
-  Label* false_label = chunk_->GetAssemblyLabel(false_block);
-
-  __ JumpIfSmi(input, false_label);
+  __ JumpIfSmi(input, instr->FalseLabel(chunk_));
 
   __ CmpObjectType(input, TestType(instr->hydrogen()), temp);
-  EmitBranch(true_block, false_block, BranchCondition(instr->hydrogen()));
+  EmitBranch(instr, BranchCondition(instr->hydrogen()));
 }
 
 
@@ -2526,12 +2494,9 @@ void LCodeGen::DoHasCachedArrayIndexAndBranch(
     LHasCachedArrayIndexAndBranch* instr) {
   Register input = ToRegister(instr->value());
 
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-
   __ test(FieldOperand(input, String::kHashFieldOffset),
           Immediate(String::kContainsCachedArrayIndexMask));
-  EmitBranch(true_block, false_block, equal);
+  EmitBranch(instr, equal);
 }
 
 
@@ -2607,25 +2572,17 @@ void LCodeGen::DoClassOfTestAndBranch(LClassOfTestAndBranch* instr) {
 
   Handle<String> class_name = instr->hydrogen()->class_name();
 
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
+  EmitClassOfTest(instr->TrueLabel(chunk_), instr->FalseLabel(chunk_),
+      class_name, input, temp, temp2);
 
-  Label* true_label = chunk_->GetAssemblyLabel(true_block);
-  Label* false_label = chunk_->GetAssemblyLabel(false_block);
-
-  EmitClassOfTest(true_label, false_label, class_name, input, temp, temp2);
-
-  EmitBranch(true_block, false_block, equal);
+  EmitBranch(instr, equal);
 }
 
 
 void LCodeGen::DoCmpMapAndBranch(LCmpMapAndBranch* instr) {
   Register reg = ToRegister(instr->value());
-  int true_block = instr->true_block_id();
-  int false_block = instr->false_block_id();
-
   __ cmp(FieldOperand(reg, HeapObject::kMapOffset), instr->map());
-  EmitBranch(true_block, false_block, equal);
+  EmitBranch(instr, equal);
 }
 
 
@@ -6243,15 +6200,12 @@ void LCodeGen::DoTypeof(LTypeof* instr) {
 
 void LCodeGen::DoTypeofIsAndBranch(LTypeofIsAndBranch* instr) {
   Register input = ToRegister(instr->value());
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-  Label* true_label = chunk_->GetAssemblyLabel(true_block);
-  Label* false_label = chunk_->GetAssemblyLabel(false_block);
 
   Condition final_branch_condition =
-      EmitTypeofIs(true_label, false_label, input, instr->type_literal());
+      EmitTypeofIs(instr->TrueLabel(chunk_), instr->FalseLabel(chunk_),
+          input, instr->type_literal());
   if (final_branch_condition != no_condition) {
-    EmitBranch(true_block, false_block, final_branch_condition);
+    EmitBranch(instr, final_branch_condition);
   }
 }
 
@@ -6332,11 +6286,9 @@ Condition LCodeGen::EmitTypeofIs(Label* true_label,
 
 void LCodeGen::DoIsConstructCallAndBranch(LIsConstructCallAndBranch* instr) {
   Register temp = ToRegister(instr->temp());
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
 
   EmitIsConstructCall(temp);
-  EmitBranch(true_block, false_block, equal);
+  EmitBranch(instr, equal);
 }
 
 
diff --git a/src/ia32/lithium-codegen-ia32.h b/src/ia32/lithium-codegen-ia32.h
index 260711b..e684527 100644
--- a/src/ia32/lithium-codegen-ia32.h
+++ b/src/ia32/lithium-codegen-ia32.h
@@ -83,7 +83,6 @@ class LCodeGen BASE_EMBEDDED {
   Heap* heap() const { return isolate()->heap(); }
   Zone* zone() const { return zone_; }
 
-  // TODO(svenpanne) Use this consistently.
   int LookupDestination(int block_id) const {
     return chunk()->LookupDestination(block_id);
   }
@@ -318,7 +317,8 @@ class LCodeGen BASE_EMBEDDED {
 
   static Condition TokenToCondition(Token::Value op, bool is_unsigned);
   void EmitGoto(int block);
-  void EmitBranch(int left_block, int right_block, Condition cc);
+  template<class InstrType>
+  void EmitBranch(InstrType instr, Condition cc);
   void EmitNumberUntagD(
       Register input,
       Register temp,
diff --git a/src/ia32/lithium-ia32.h b/src/ia32/lithium-ia32.h
index 5529759..b04f3ee 100644
--- a/src/ia32/lithium-ia32.h
+++ b/src/ia32/lithium-ia32.h
@@ -483,17 +483,44 @@ class LUnknownOSRValue: public LTemplateInstruction<1, 0, 0> {
 template<int I, int T>
 class LControlInstruction: public LTemplateInstruction<0, I, T> {
  public:
+  LControlInstruction() : false_label_(NULL), true_label_(NULL) { }
+
   virtual bool IsControl() const { return true; }
 
   int SuccessorCount() { return hydrogen()->SuccessorCount(); }
   HBasicBlock* SuccessorAt(int i) { return hydrogen()->SuccessorAt(i); }
-  int true_block_id() { return hydrogen()->SuccessorAt(0)->block_id(); }
-  int false_block_id() { return hydrogen()->SuccessorAt(1)->block_id(); }
+
+  int TrueDestination(LChunk* chunk) {
+    return chunk->LookupDestination(true_block_id());
+  }
+  int FalseDestination(LChunk* chunk) {
+    return chunk->LookupDestination(false_block_id());
+  }
+
+  Label* TrueLabel(LChunk* chunk) {
+    if (true_label_ == NULL) {
+      true_label_ = chunk->GetAssemblyLabel(TrueDestination(chunk));
+    }
+    return true_label_;
+  }
+  Label* FalseLabel(LChunk* chunk) {
+    if (false_label_ == NULL) {
+      false_label_ = chunk->GetAssemblyLabel(FalseDestination(chunk));
+    }
+    return false_label_;
+  }
+
+ protected:
+  int true_block_id() { return SuccessorAt(0)->block_id(); }
+  int false_block_id() { return SuccessorAt(1)->block_id(); }
 
  private:
   HControlInstruction* hydrogen() {
     return HControlInstruction::cast(this->hydrogen_value());
   }
+
+  Label* false_label_;
+  Label* true_label_;
 };
 
 
@@ -1207,7 +1234,7 @@ class LBranch: public LControlInstruction<1, 1> {
 };
 
 
-class LCmpMapAndBranch: public LTemplateInstruction<0, 1, 0> {
+class LCmpMapAndBranch: public LControlInstruction<1, 0> {
  public:
   explicit LCmpMapAndBranch(LOperand* value) {
     inputs_[0] = value;
@@ -1218,15 +1245,7 @@ class LCmpMapAndBranch: public LTemplateInstruction<0, 1, 0> {
   DECLARE_CONCRETE_INSTRUCTION(CmpMapAndBranch, "cmp-map-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(CompareMap)
 
-  virtual bool IsControl() const { return true; }
-
   Handle<Map> map() const { return hydrogen()->map(); }
-  int true_block_id() const {
-    return hydrogen()->FirstSuccessor()->block_id();
-  }
-  int false_block_id() const {
-    return hydrogen()->SecondSuccessor()->block_id();
-  }
 };
 
 
diff --git a/src/x64/lithium-codegen-x64.cc b/src/x64/lithium-codegen-x64.cc
index 5960726..1dac13d 100644
--- a/src/x64/lithium-codegen-x64.cc
+++ b/src/x64/lithium-codegen-x64.cc
@@ -1862,10 +1862,12 @@ int LCodeGen::GetNextEmittedBlock() const {
 }
 
 
-void LCodeGen::EmitBranch(int left_block, int right_block, Condition cc) {
+template<class InstrType>
+void LCodeGen::EmitBranch(InstrType instr, Condition cc) {
+  int right_block = instr->FalseDestination(chunk_);
+  int left_block = instr->TrueDestination(chunk_);
+
   int next_block = GetNextEmittedBlock();
-  right_block = chunk_->LookupDestination(right_block);
-  left_block = chunk_->LookupDestination(left_block);
 
   if (right_block == left_block) {
     EmitGoto(left_block);
@@ -1888,26 +1890,23 @@ void LCodeGen::DoDebugBreak(LDebugBreak* instr) {
 
 
 void LCodeGen::DoBranch(LBranch* instr) {
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-
   Representation r = instr->hydrogen()->value()->representation();
   if (r.IsInteger32()) {
     ASSERT(!info()->IsStub());
     Register reg = ToRegister(instr->value());
     __ testl(reg, reg);
-    EmitBranch(true_block, false_block, not_zero);
+    EmitBranch(instr, not_zero);
   } else if (r.IsSmi()) {
     ASSERT(!info()->IsStub());
     Register reg = ToRegister(instr->value());
     __ testq(reg, reg);
-    EmitBranch(true_block, false_block, not_zero);
+    EmitBranch(instr, not_zero);
   } else if (r.IsDouble()) {
     ASSERT(!info()->IsStub());
     XMMRegister reg = ToDoubleRegister(instr->value());
     __ xorps(xmm0, xmm0);
     __ ucomisd(reg, xmm0);
-    EmitBranch(true_block, false_block, not_equal);
+    EmitBranch(instr, not_equal);
   } else {
     ASSERT(r.IsTagged());
     Register reg = ToRegister(instr->value());
@@ -1915,15 +1914,12 @@ void LCodeGen::DoBranch(LBranch* instr) {
     if (type.IsBoolean()) {
       ASSERT(!info()->IsStub());
       __ CompareRoot(reg, Heap::kTrueValueRootIndex);
-      EmitBranch(true_block, false_block, equal);
+      EmitBranch(instr, equal);
     } else if (type.IsSmi()) {
       ASSERT(!info()->IsStub());
       __ SmiCompare(reg, Smi::FromInt(0));
-      EmitBranch(true_block, false_block, not_equal);
+      EmitBranch(instr, not_equal);
     } else {
-      Label* true_label = chunk_->GetAssemblyLabel(true_block);
-      Label* false_label = chunk_->GetAssemblyLabel(false_block);
-
       ToBooleanStub::Types expected = instr->hydrogen()->expected_input_types();
       // Avoid deopts in the case where we've never executed this path before.
       if (expected.IsEmpty()) expected = ToBooleanStub::all_types();
@@ -1931,27 +1927,27 @@ void LCodeGen::DoBranch(LBranch* instr) {
       if (expected.Contains(ToBooleanStub::UNDEFINED)) {
         // undefined -> false.
         __ CompareRoot(reg, Heap::kUndefinedValueRootIndex);
-        __ j(equal, false_label);
+        __ j(equal, instr->FalseLabel(chunk_));
       }
       if (expected.Contains(ToBooleanStub::BOOLEAN)) {
         // true -> true.
         __ CompareRoot(reg, Heap::kTrueValueRootIndex);
-        __ j(equal, true_label);
+        __ j(equal, instr->TrueLabel(chunk_));
         // false -> false.
         __ CompareRoot(reg, Heap::kFalseValueRootIndex);
-        __ j(equal, false_label);
+        __ j(equal, instr->FalseLabel(chunk_));
       }
       if (expected.Contains(ToBooleanStub::NULL_TYPE)) {
         // 'null' -> false.
         __ CompareRoot(reg, Heap::kNullValueRootIndex);
-        __ j(equal, false_label);
+        __ j(equal, instr->FalseLabel(chunk_));
       }
 
       if (expected.Contains(ToBooleanStub::SMI)) {
         // Smis: 0 -> false, all other -> true.
         __ Cmp(reg, Smi::FromInt(0));
-        __ j(equal, false_label);
-        __ JumpIfSmi(reg, true_label);
+        __ j(equal, instr->FalseLabel(chunk_));
+        __ JumpIfSmi(reg, instr->TrueLabel(chunk_));
       } else if (expected.NeedsMap()) {
         // If we need a map later and have a Smi -> deopt.
         __ testb(reg, Immediate(kSmiTagMask));
@@ -1966,14 +1962,14 @@ void LCodeGen::DoBranch(LBranch* instr) {
           // Undetectable -> false.
           __ testb(FieldOperand(map, Map::kBitFieldOffset),
                    Immediate(1 << Map::kIsUndetectable));
-          __ j(not_zero, false_label);
+          __ j(not_zero, instr->FalseLabel(chunk_));
         }
       }
 
       if (expected.Contains(ToBooleanStub::SPEC_OBJECT)) {
         // spec object -> true.
         __ CmpInstanceType(map, FIRST_SPEC_OBJECT_TYPE);
-        __ j(above_equal, true_label);
+        __ j(above_equal, instr->TrueLabel(chunk_));
       }
 
       if (expected.Contains(ToBooleanStub::STRING)) {
@@ -1982,8 +1978,8 @@ void LCodeGen::DoBranch(LBranch* instr) {
         __ CmpInstanceType(map, FIRST_NONSTRING_TYPE);
         __ j(above_equal, &not_string, Label::kNear);
         __ cmpq(FieldOperand(reg, String::kLengthOffset), Immediate(0));
-        __ j(not_zero, true_label);
-        __ jmp(false_label);
+        __ j(not_zero, instr->TrueLabel(chunk_));
+        __ jmp(instr->FalseLabel(chunk_));
         __ bind(&not_string);
       }
 
@@ -1994,8 +1990,8 @@ void LCodeGen::DoBranch(LBranch* instr) {
         __ j(not_equal, &not_heap_number, Label::kNear);
         __ xorps(xmm0, xmm0);
         __ ucomisd(xmm0, FieldOperand(reg, HeapNumber::kValueOffset));
-        __ j(zero, false_label);
-        __ jmp(true_label);
+        __ j(zero, instr->FalseLabel(chunk_));
+        __ jmp(instr->TrueLabel(chunk_));
         __ bind(&not_heap_number);
       }
 
@@ -2049,24 +2045,21 @@ inline Condition LCodeGen::TokenToCondition(Token::Value op, bool is_unsigned) {
 void LCodeGen::DoCmpIDAndBranch(LCmpIDAndBranch* instr) {
   LOperand* left = instr->left();
   LOperand* right = instr->right();
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
   Condition cc = TokenToCondition(instr->op(), instr->is_double());
 
   if (left->IsConstantOperand() && right->IsConstantOperand()) {
     // We can statically evaluate the comparison.
     double left_val = ToDouble(LConstantOperand::cast(left));
     double right_val = ToDouble(LConstantOperand::cast(right));
-    int next_block =
-      EvalComparison(instr->op(), left_val, right_val) ? true_block
-                                                       : false_block;
+    int next_block = EvalComparison(instr->op(), left_val, right_val) ?
+        instr->TrueDestination(chunk_) : instr->FalseDestination(chunk_);
     EmitGoto(next_block);
   } else {
     if (instr->is_double()) {
       // Don't base result on EFLAGS when a NaN is involved. Instead
       // jump to the false block.
       __ ucomisd(ToDoubleRegister(left), ToDoubleRegister(right));
-      __ j(parity_even, chunk_->GetAssemblyLabel(false_block));
+      __ j(parity_even, instr->FalseLabel(chunk_));
     } else {
       int32_t value;
       if (right->IsConstantOperand()) {
@@ -2105,15 +2098,13 @@ void LCodeGen::DoCmpIDAndBranch(LCmpIDAndBranch* instr) {
         }
       }
     }
-    EmitBranch(true_block, false_block, cc);
+    EmitBranch(instr, cc);
   }
 }
 
 
 void LCodeGen::DoCmpObjectEqAndBranch(LCmpObjectEqAndBranch* instr) {
   Register left = ToRegister(instr->left());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
 
   if (instr->right()->IsConstantOperand()) {
     Handle<Object> right = ToHandle(LConstantOperand::cast(instr->right()));
@@ -2122,17 +2113,15 @@ void LCodeGen::DoCmpObjectEqAndBranch(LCmpObjectEqAndBranch* instr) {
     Register right = ToRegister(instr->right());
     __ cmpq(left, right);
   }
-  EmitBranch(true_block, false_block, equal);
+  EmitBranch(instr, equal);
 }
 
 
 void LCodeGen::DoCmpConstantEqAndBranch(LCmpConstantEqAndBranch* instr) {
   Register left = ToRegister(instr->left());
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
 
   __ cmpq(left, Immediate(instr->hydrogen()->right()));
-  EmitBranch(true_block, false_block, equal);
+  EmitBranch(instr, equal);
 }
 
 
@@ -2164,14 +2153,10 @@ Condition LCodeGen::EmitIsObject(Register input,
 void LCodeGen::DoIsObjectAndBranch(LIsObjectAndBranch* instr) {
   Register reg = ToRegister(instr->value());
 
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-  Label* true_label = chunk_->GetAssemblyLabel(true_block);
-  Label* false_label = chunk_->GetAssemblyLabel(false_block);
+  Condition true_cond = EmitIsObject(
+      reg, instr->FalseLabel(chunk_), instr->TrueLabel(chunk_));
 
-  Condition true_cond = EmitIsObject(reg, false_label, true_label);
-
-  EmitBranch(true_block, false_block, true_cond);
+  EmitBranch(instr, true_cond);
 }
 
 
@@ -2189,20 +2174,13 @@ void LCodeGen::DoIsStringAndBranch(LIsStringAndBranch* instr) {
   Register reg = ToRegister(instr->value());
   Register temp = ToRegister(instr->temp());
 
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-  Label* false_label = chunk_->GetAssemblyLabel(false_block);
-
-  Condition true_cond = EmitIsString(reg, temp, false_label);
+  Condition true_cond = EmitIsString(reg, temp, instr->FalseLabel(chunk_));
 
-  EmitBranch(true_block, false_block, true_cond);
+  EmitBranch(instr, true_cond);
 }
 
 
 void LCodeGen::DoIsSmiAndBranch(LIsSmiAndBranch* instr) {
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-
   Condition is_smi;
   if (instr->value()->IsRegister()) {
     Register input = ToRegister(instr->value());
@@ -2211,7 +2189,7 @@ void LCodeGen::DoIsSmiAndBranch(LIsSmiAndBranch* instr) {
     Operand input = ToOperand(instr->value());
     is_smi = masm()->CheckSmi(input);
   }
-  EmitBranch(true_block, false_block, is_smi);
+  EmitBranch(instr, is_smi);
 }
 
 
@@ -2219,21 +2197,16 @@ void LCodeGen::DoIsUndetectableAndBranch(LIsUndetectableAndBranch* instr) {
   Register input = ToRegister(instr->value());
   Register temp = ToRegister(instr->temp());
 
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-
-  __ JumpIfSmi(input, chunk_->GetAssemblyLabel(false_block));
+  __ JumpIfSmi(input, instr->FalseLabel(chunk_));
   __ movq(temp, FieldOperand(input, HeapObject::kMapOffset));
   __ testb(FieldOperand(temp, Map::kBitFieldOffset),
            Immediate(1 << Map::kIsUndetectable));
-  EmitBranch(true_block, false_block, not_zero);
+  EmitBranch(instr, not_zero);
 }
 
 
 void LCodeGen::DoStringCompareAndBranch(LStringCompareAndBranch* instr) {
   Token::Value op = instr->op();
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
 
   Handle<Code> ic = CompareIC::GetUninitialized(isolate(), op);
   CallCode(ic, RelocInfo::CODE_TARGET, instr);
@@ -2241,7 +2214,7 @@ void LCodeGen::DoStringCompareAndBranch(LStringCompareAndBranch* instr) {
   Condition condition = TokenToCondition(op, false);
   __ testq(rax, rax);
 
-  EmitBranch(true_block, false_block, condition);
+  EmitBranch(instr, condition);
 }
 
 
@@ -2268,15 +2241,10 @@ static Condition BranchCondition(HHasInstanceTypeAndBranch* instr) {
 void LCodeGen::DoHasInstanceTypeAndBranch(LHasInstanceTypeAndBranch* instr) {
   Register input = ToRegister(instr->value());
 
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-
-  Label* false_label = chunk_->GetAssemblyLabel(false_block);
-
-  __ JumpIfSmi(input, false_label);
+  __ JumpIfSmi(input, instr->FalseLabel(chunk_));
 
   __ CmpObjectType(input, TestType(instr->hydrogen()), kScratchRegister);
-  EmitBranch(true_block, false_block, BranchCondition(instr->hydrogen()));
+  EmitBranch(instr, BranchCondition(instr->hydrogen()));
 }
 
 
@@ -2296,12 +2264,9 @@ void LCodeGen::DoHasCachedArrayIndexAndBranch(
     LHasCachedArrayIndexAndBranch* instr) {
   Register input = ToRegister(instr->value());
 
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-
   __ testl(FieldOperand(input, String::kHashFieldOffset),
            Immediate(String::kContainsCachedArrayIndexMask));
-  EmitBranch(true_block, false_block, equal);
+  EmitBranch(instr, equal);
 }
 
 
@@ -2379,25 +2344,18 @@ void LCodeGen::DoClassOfTestAndBranch(LClassOfTestAndBranch* instr) {
   Register temp2 = ToRegister(instr->temp2());
   Handle<String> class_name = instr->hydrogen()->class_name();
 
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-
-  Label* true_label = chunk_->GetAssemblyLabel(true_block);
-  Label* false_label = chunk_->GetAssemblyLabel(false_block);
-
-  EmitClassOfTest(true_label, false_label, class_name, input, temp, temp2);
+  EmitClassOfTest(instr->TrueLabel(chunk_), instr->FalseLabel(chunk_),
+      class_name, input, temp, temp2);
 
-  EmitBranch(true_block, false_block, equal);
+  EmitBranch(instr, equal);
 }
 
 
 void LCodeGen::DoCmpMapAndBranch(LCmpMapAndBranch* instr) {
   Register reg = ToRegister(instr->value());
-  int true_block = instr->true_block_id();
-  int false_block = instr->false_block_id();
 
   __ Cmp(FieldOperand(reg, HeapObject::kMapOffset), instr->map());
-  EmitBranch(true_block, false_block, equal);
+  EmitBranch(instr, equal);
 }
 
 
@@ -5347,15 +5305,12 @@ void LCodeGen::EmitPushTaggedOperand(LOperand* operand) {
 
 void LCodeGen::DoTypeofIsAndBranch(LTypeofIsAndBranch* instr) {
   Register input = ToRegister(instr->value());
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-  Label* true_label = chunk_->GetAssemblyLabel(true_block);
-  Label* false_label = chunk_->GetAssemblyLabel(false_block);
 
   Condition final_branch_condition =
-      EmitTypeofIs(true_label, false_label, input, instr->type_literal());
+      EmitTypeofIs(instr->TrueLabel(chunk_),
+          instr->FalseLabel(chunk_), input, instr->type_literal());
   if (final_branch_condition != no_condition) {
-    EmitBranch(true_block, false_block, final_branch_condition);
+    EmitBranch(instr, final_branch_condition);
   }
 }
 
@@ -5438,11 +5393,9 @@ Condition LCodeGen::EmitTypeofIs(Label* true_label,
 
 void LCodeGen::DoIsConstructCallAndBranch(LIsConstructCallAndBranch* instr) {
   Register temp = ToRegister(instr->temp());
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
 
   EmitIsConstructCall(temp);
-  EmitBranch(true_block, false_block, equal);
+  EmitBranch(instr, equal);
 }
 
 
diff --git a/src/x64/lithium-codegen-x64.h b/src/x64/lithium-codegen-x64.h
index b0114d0..116f875 100644
--- a/src/x64/lithium-codegen-x64.h
+++ b/src/x64/lithium-codegen-x64.h
@@ -79,7 +79,6 @@ class LCodeGen BASE_EMBEDDED {
   Heap* heap() const { return isolate()->heap(); }
   Zone* zone() const { return zone_; }
 
-  // TODO(svenpanne) Use this consistently.
   int LookupDestination(int block_id) const {
     return chunk()->LookupDestination(block_id);
   }
@@ -283,7 +282,8 @@ class LCodeGen BASE_EMBEDDED {
 
   static Condition TokenToCondition(Token::Value op, bool is_unsigned);
   void EmitGoto(int block);
-  void EmitBranch(int left_block, int right_block, Condition cc);
+  template<class InstrType>
+  void EmitBranch(InstrType instr, Condition cc);
   void EmitNumberUntagD(
       Register input,
       XMMRegister result,
diff --git a/src/x64/lithium-x64.h b/src/x64/lithium-x64.h
index 94efc29..c1a4817 100644
--- a/src/x64/lithium-x64.h
+++ b/src/x64/lithium-x64.h
@@ -490,17 +490,44 @@ class LUnknownOSRValue: public LTemplateInstruction<1, 0, 0> {
 template<int I, int T>
 class LControlInstruction: public LTemplateInstruction<0, I, T> {
  public:
+  LControlInstruction() : false_label_(NULL), true_label_(NULL) { }
+
   virtual bool IsControl() const { return true; }
 
   int SuccessorCount() { return hydrogen()->SuccessorCount(); }
   HBasicBlock* SuccessorAt(int i) { return hydrogen()->SuccessorAt(i); }
-  int true_block_id() { return hydrogen()->SuccessorAt(0)->block_id(); }
-  int false_block_id() { return hydrogen()->SuccessorAt(1)->block_id(); }
+
+  int TrueDestination(LChunk* chunk) {
+    return chunk->LookupDestination(true_block_id());
+  }
+  int FalseDestination(LChunk* chunk) {
+    return chunk->LookupDestination(false_block_id());
+  }
+
+  Label* TrueLabel(LChunk* chunk) {
+    if (true_label_ == NULL) {
+      true_label_ = chunk->GetAssemblyLabel(TrueDestination(chunk));
+    }
+    return true_label_;
+  }
+  Label* FalseLabel(LChunk* chunk) {
+    if (false_label_ == NULL) {
+      false_label_ = chunk->GetAssemblyLabel(FalseDestination(chunk));
+    }
+    return false_label_;
+  }
+
+ protected:
+  int true_block_id() { return SuccessorAt(0)->block_id(); }
+  int false_block_id() { return SuccessorAt(1)->block_id(); }
 
  private:
   HControlInstruction* hydrogen() {
     return HControlInstruction::cast(this->hydrogen_value());
   }
+
+  Label* false_label_;
+  Label* true_label_;
 };
 
 
@@ -1191,7 +1218,7 @@ class LDebugBreak: public LTemplateInstruction<0, 0, 0> {
 };
 
 
-class LCmpMapAndBranch: public LTemplateInstruction<0, 1, 0> {
+class LCmpMapAndBranch: public LControlInstruction<1, 0> {
  public:
   explicit LCmpMapAndBranch(LOperand* value) {
     inputs_[0] = value;
@@ -1202,15 +1229,7 @@ class LCmpMapAndBranch: public LTemplateInstruction<0, 1, 0> {
   DECLARE_CONCRETE_INSTRUCTION(CmpMapAndBranch, "cmp-map-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(CompareMap)
 
-  virtual bool IsControl() const { return true; }
-
   Handle<Map> map() const { return hydrogen()->map(); }
-  int true_block_id() const {
-    return hydrogen()->FirstSuccessor()->block_id();
-  }
-  int false_block_id() const {
-    return hydrogen()->SecondSuccessor()->block_id();
-  }
 };
 
 
-- 
2.7.4