[stubs,interpreter] Optimise SMI loading for 64-bit targets.

Adding new methods to the code stub assembler and interpreter
assembler to combine loading and untagging SMIs, so that on 64-bit
architectures we can avoid loading the full 64 bits and load the
32 interesting bits directly instead.

Review-Url: https://codereview.chromium.org/2183923003
Cr-Commit-Position: refs/heads/master@{#38361}

src/builtins/builtins-string.cc

@@ -51,11 +51,8 @@ void Builtins::Generate_StringFromCharCode(CodeStubAssembler* assembler) {
   assembler->Bind(&if_notoneargument);
   {
     // Determine the resulting string length.
-    Node* parent_frame_length =
-        assembler->Load(MachineType::Pointer(), parent_frame_pointer,
-                        assembler->IntPtrConstant(
-                            ArgumentsAdaptorFrameConstants::kLengthOffset));
-    Node* length = assembler->SmiToWord(parent_frame_length);
+    Node* length = assembler->LoadAndUntagSmi(
+        parent_frame_pointer, ArgumentsAdaptorFrameConstants::kLengthOffset);
 
     // Assume that the resulting string contains only one-byte characters.
     Node* result = assembler->AllocateSeqOneByteString(context, length);

src/code-stub-assembler.cc

@@ -74,7 +74,7 @@ Node* CodeStubAssembler::TheHoleConstant() {
 }
 
 Node* CodeStubAssembler::HashSeed() {
-  return SmiToWord32(LoadRoot(Heap::kHashSeedRootIndex));
+  return LoadAndUntagToWord32Root(Heap::kHashSeedRootIndex);
 }
 
 Node* CodeStubAssembler::StaleRegisterConstant() {
@@ -914,6 +914,60 @@ Node* CodeStubAssembler::LoadObjectField(Node* object, Node* offset,
   return Load(rep, object, IntPtrSub(offset, IntPtrConstant(kHeapObjectTag)));
 }
 
+Node* CodeStubAssembler::LoadAndUntagObjectField(Node* object, int offset) {
+  if (Is64()) {
+#if V8_TARGET_LITTLE_ENDIAN
+    offset += kPointerSize / 2;
+#endif
+    return ChangeInt32ToInt64(
+        LoadObjectField(object, offset, MachineType::Int32()));
+  } else {
+    return SmiToWord(LoadObjectField(object, offset, MachineType::AnyTagged()));
+  }
+}
+
+Node* CodeStubAssembler::LoadAndUntagToWord32ObjectField(Node* object,
+                                                         int offset) {
+  if (Is64()) {
+#if V8_TARGET_LITTLE_ENDIAN
+    offset += kPointerSize / 2;
+#endif
+    return LoadObjectField(object, offset, MachineType::Int32());
+  } else {
+    return SmiToWord32(
+        LoadObjectField(object, offset, MachineType::AnyTagged()));
+  }
+}
+
+Node* CodeStubAssembler::LoadAndUntagSmi(Node* base, int index) {
+  if (Is64()) {
+#if V8_TARGET_LITTLE_ENDIAN
+    index += kPointerSize / 2;
+#endif
+    return ChangeInt32ToInt64(
+        Load(MachineType::Int32(), base, IntPtrConstant(index)));
+  } else {
+    return SmiToWord(
+        Load(MachineType::AnyTagged(), base, IntPtrConstant(index)));
+  }
+}
+
+Node* CodeStubAssembler::LoadAndUntagToWord32Root(
+    Heap::RootListIndex root_index) {
+  Node* roots_array_start =
+      ExternalConstant(ExternalReference::roots_array_start(isolate()));
+  int index = root_index * kPointerSize;
+  if (Is64()) {
+#if V8_TARGET_LITTLE_ENDIAN
+    index += kPointerSize / 2;
+#endif
+    return Load(MachineType::Int32(), roots_array_start, IntPtrConstant(index));
+  } else {
+    return SmiToWord32(Load(MachineType::AnyTagged(), roots_array_start,
+                            IntPtrConstant(index)));
+  }
+}
+
 Node* CodeStubAssembler::LoadHeapNumberValue(Node* object) {
   return LoadObjectField(object, HeapNumber::kValueOffset,
                          MachineType::Float64());
@@ -940,8 +994,8 @@ Node* CodeStubAssembler::LoadElements(Node* object) {
   return LoadObjectField(object, JSObject::kElementsOffset);
 }
 
-Node* CodeStubAssembler::LoadFixedArrayBaseLength(Node* array) {
-  return LoadObjectField(array, FixedArrayBase::kLengthOffset);
+Node* CodeStubAssembler::LoadAndUntagFixedArrayBaseLength(Node* array) {
+  return LoadAndUntagObjectField(array, FixedArrayBase::kLengthOffset);
 }
 
 Node* CodeStubAssembler::LoadMapBitField(Node* map) {
@@ -1056,6 +1110,25 @@ Node* CodeStubAssembler::LoadFixedArrayElement(Node* object, Node* index_node,
   return Load(MachineType::AnyTagged(), object, offset);
 }
 
+Node* CodeStubAssembler::LoadAndUntagToWord32FixedArrayElement(
+    Node* object, Node* index_node, int additional_offset,
+    ParameterMode parameter_mode) {
+  int32_t header_size =
+      FixedArray::kHeaderSize + additional_offset - kHeapObjectTag;
+#if V8_TARGET_LITTLE_ENDIAN
+  if (Is64()) {
+    header_size += kPointerSize / 2;
+  }
+#endif
+  Node* offset = ElementOffsetFromIndex(index_node, FAST_HOLEY_ELEMENTS,
+                                        parameter_mode, header_size);
+  if (Is64()) {
+    return Load(MachineType::Int32(), object, offset);
+  } else {
+    return SmiToWord32(Load(MachineType::AnyTagged(), object, offset));
+  }
+}
+
 Node* CodeStubAssembler::LoadFixedDoubleArrayElement(
     Node* object, Node* index_node, MachineType machine_type,
     int additional_offset, ParameterMode parameter_mode) {
@@ -1915,7 +1988,7 @@ Node* CodeStubAssembler::StringCharCodeAt(Node* string, Node* index) {
         {
           // The {string} is a SlicedString, continue with its parent.
           Node* string_offset =
-              SmiToWord(LoadObjectField(string, SlicedString::kOffsetOffset));
+              LoadAndUntagObjectField(string, SlicedString::kOffsetOffset);
           Node* string_parent =
               LoadObjectField(string, SlicedString::kParentOffset);
           var_index.Bind(IntPtrAdd(index, string_offset));
@@ -2086,8 +2159,8 @@ void CodeStubAssembler::NameDictionaryLookup(Node* dictionary,
   DCHECK_EQ(MachineRepresentation::kWord32, var_name_index->rep());
   Comment("NameDictionaryLookup");
 
-  Node* capacity = SmiToWord32(LoadFixedArrayElement(
-      dictionary, Int32Constant(Dictionary::kCapacityIndex)));
+  Node* capacity = LoadAndUntagToWord32FixedArrayElement(
+      dictionary, Int32Constant(Dictionary::kCapacityIndex));
   Node* mask = Int32Sub(capacity, Int32Constant(1));
   Node* hash = LoadNameHash(unique_name);
 
@@ -2166,8 +2239,8 @@ void CodeStubAssembler::NumberDictionaryLookup(Node* dictionary, Node* key,
   DCHECK_EQ(MachineRepresentation::kWord32, var_entry->rep());
   Comment("NumberDictionaryLookup");
 
-  Node* capacity = SmiToWord32(LoadFixedArrayElement(
-      dictionary, Int32Constant(Dictionary::kCapacityIndex)));
+  Node* capacity = LoadAndUntagToWord32FixedArrayElement(
+      dictionary, Int32Constant(Dictionary::kCapacityIndex));
   Node* mask = Int32Sub(capacity, Int32Constant(1));
 
   Node* seed;
@@ -2358,8 +2431,8 @@ void CodeStubAssembler::LoadPropertyFromFastObject(Node* object, Node* map,
       (DescriptorArray::kDescriptorValue - DescriptorArray::kDescriptorKey) *
       kPointerSize;
 
-  Node* details = SmiToWord32(
-      LoadFixedArrayElement(descriptors, name_index, name_to_details_offset));
+  Node* details = LoadAndUntagToWord32FixedArrayElement(descriptors, name_index,
+                                                        name_to_details_offset);
   var_details->Bind(details);
 
   Node* location = BitFieldDecode<PropertyDetails::LocationField>(details);
@@ -2465,8 +2538,8 @@ void CodeStubAssembler::LoadPropertyFromNameDictionary(Node* dictionary,
       (NameDictionary::kEntryValueIndex - NameDictionary::kEntryKeyIndex) *
       kPointerSize;
 
-  Node* details = SmiToWord32(
-      LoadFixedArrayElement(dictionary, name_index, name_to_details_offset));
+  Node* details = LoadAndUntagToWord32FixedArrayElement(dictionary, name_index,
+                                                        name_to_details_offset);
 
   var_details->Bind(details);
   var_value->Bind(
@@ -2494,8 +2567,8 @@ void CodeStubAssembler::LoadPropertyFromGlobalDictionary(Node* dictionary,
 
   var_value->Bind(value);
 
-  Node* details =
-      SmiToWord32(LoadObjectField(property_cell, PropertyCell::kDetailsOffset));
+  Node* details = LoadAndUntagToWord32ObjectField(property_cell,
+                                                  PropertyCell::kDetailsOffset);
   var_details->Bind(details);
 
   Comment("] LoadPropertyFromGlobalDictionary");
@@ -2633,9 +2706,9 @@ void CodeStubAssembler::TryLookupElement(Node* object, Node* map,
   Bind(&if_isobjectorsmi);
   {
     Node* elements = LoadElements(object);
-    Node* length = LoadFixedArrayBaseLength(elements);
+    Node* length = LoadAndUntagFixedArrayBaseLength(elements);
 
-    GotoUnless(Uint32LessThan(index, SmiToWord32(length)), if_not_found);
+    GotoUnless(Uint32LessThan(index, length), if_not_found);
 
     Node* element = LoadFixedArrayElement(elements, index);
     Node* the_hole = TheHoleConstant();
@@ -2644,9 +2717,9 @@ void CodeStubAssembler::TryLookupElement(Node* object, Node* map,
   Bind(&if_isdouble);
   {
     Node* elements = LoadElements(object);
-    Node* length = LoadFixedArrayBaseLength(elements);
+    Node* length = LoadAndUntagFixedArrayBaseLength(elements);
 
-    GotoUnless(Uint32LessThan(index, SmiToWord32(length)), if_not_found);
+    GotoUnless(Uint32LessThan(index, length), if_not_found);
 
     if (kPointerSize == kDoubleSize) {
       Node* element =
@@ -3053,7 +3126,7 @@ void CodeStubAssembler::HandlePolymorphicCase(
 
     Bind(&next_entry);
   }
-  Node* length = SmiToWord32(LoadFixedArrayBaseLength(feedback));
+  Node* length = LoadAndUntagFixedArrayBaseLength(feedback);
 
   // Loop from {unroll_count}*kEntrySize to {length}.
   Variable var_index(this, MachineRepresentation::kWord32);

src/code-stub-assembler.h

@@ -156,6 +156,15 @@ class CodeStubAssembler : public compiler::CodeAssembler {
   compiler::Node* LoadObjectField(compiler::Node* object,
                                   compiler::Node* offset,
                                   MachineType rep = MachineType::AnyTagged());
+  // Load a SMI field and untag it.
+  compiler::Node* LoadAndUntagObjectField(compiler::Node* object, int offset);
+  // Load a SMI field, untag it, and convert to Word32.
+  compiler::Node* LoadAndUntagToWord32ObjectField(compiler::Node* object,
+                                                  int offset);
+  // Load a SMI and untag it.
+  compiler::Node* LoadAndUntagSmi(compiler::Node* base, int index);
+  // Load a SMI root, untag it, and convert to Word32.
+  compiler::Node* LoadAndUntagToWord32Root(Heap::RootListIndex root_index);
 
   // Load the floating point value of a HeapNumber.
   compiler::Node* LoadHeapNumberValue(compiler::Node* object);
@@ -170,7 +179,7 @@ class CodeStubAssembler : public compiler::CodeAssembler {
   // Load the elements backing store of a JSObject.
   compiler::Node* LoadElements(compiler::Node* object);
   // Load the length of a fixed array base instance.
-  compiler::Node* LoadFixedArrayBaseLength(compiler::Node* array);
+  compiler::Node* LoadAndUntagFixedArrayBaseLength(compiler::Node* array);
   // Load the bit field of a Map.
   compiler::Node* LoadMapBitField(compiler::Node* map);
   // Load bit field 2 of a map.
@@ -212,6 +221,11 @@ class CodeStubAssembler : public compiler::CodeAssembler {
       compiler::Node* object, compiler::Node* int32_index,
       int additional_offset = 0,
       ParameterMode parameter_mode = INTEGER_PARAMETERS);
+  // Load an array element from a FixedArray, untag it and return it as Word32.
+  compiler::Node* LoadAndUntagToWord32FixedArrayElement(
+      compiler::Node* object, compiler::Node* int32_index,
+      int additional_offset = 0,
+      ParameterMode parameter_mode = INTEGER_PARAMETERS);
   // Load an array element from a FixedDoubleArray.
   compiler::Node* LoadFixedDoubleArrayElement(
       compiler::Node* object, compiler::Node* int32_index,

src/compiler/arm64/code-generator-arm64.cc

@@ -1531,6 +1531,9 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
     case kArm64Strh:
       __ Strh(i.InputOrZeroRegister64(0), i.MemoryOperand(1));
       break;
+    case kArm64Ldrsw:
+      __ Ldrsw(i.OutputRegister(), i.MemoryOperand());
+      break;
     case kArm64LdrW:
       __ Ldr(i.OutputRegister32(), i.MemoryOperand());
       break;

src/compiler/arm64/instruction-codes-arm64.h

@@ -147,6 +147,7 @@ namespace compiler {
   V(Arm64Ldrh)                     \
   V(Arm64Ldrsh)                    \
   V(Arm64Strh)                     \
+  V(Arm64Ldrsw)                    \
   V(Arm64LdrW)                     \
   V(Arm64StrW)                     \
   V(Arm64Ldr)                      \

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

@@ -144,6 +144,7 @@ int InstructionScheduler::GetTargetInstructionFlags(
     case kArm64Ldrsb:
     case kArm64Ldrh:
     case kArm64Ldrsh:
+    case kArm64Ldrsw:
     case kArm64LdrW:
     case kArm64Ldr:
       return kIsLoadOperation;
@@ -236,6 +237,7 @@ int InstructionScheduler::GetInstructionLatency(const Instruction* instr) {
     case kArm64Ldrh:
     case kArm64Ldrsb:
     case kArm64Ldrsh:
+    case kArm64Ldrsw:
       return 11;
 
     case kCheckedLoadInt8:

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

@@ -161,7 +161,6 @@ void VisitRRO(InstructionSelector* selector, ArchOpcode opcode, Node* node,
                  g.UseOperand(node->InputAt(1), operand_mode));
 }
 
-
 bool TryMatchAnyShift(InstructionSelector* selector, Node* node,
                       Node* input_node, InstructionCode* opcode, bool try_ror) {
   Arm64OperandGenerator g(selector);
@@ -458,18 +457,43 @@ int32_t LeftShiftForReducedMultiply(Matcher* m) {
 
 }  // namespace
 
-
-void InstructionSelector::VisitLoad(Node* node) {
-  LoadRepresentation load_rep = LoadRepresentationOf(node->op());
-  MachineRepresentation rep = load_rep.representation();
-  Arm64OperandGenerator g(this);
+void EmitLoad(InstructionSelector* selector, Node* node, InstructionCode opcode,
+              ImmediateMode immediate_mode, MachineRepresentation rep,
+              Node* output = nullptr) {
+  Arm64OperandGenerator g(selector);
   Node* base = node->InputAt(0);
   Node* index = node->InputAt(1);
-  InstructionCode opcode = kArchNop;
-  ImmediateMode immediate_mode = kNoImmediate;
   InstructionOperand inputs[3];
   size_t input_count = 0;
   InstructionOperand outputs[1];
+
+  // If output is not nullptr, use that as the output register. This
+  // is used when we merge a conversion into the load.
+  outputs[0] = g.DefineAsRegister(output == nullptr ? node : output);
+  inputs[0] = g.UseRegister(base);
+
+  if (g.CanBeImmediate(index, immediate_mode)) {
+    input_count = 2;
+    inputs[1] = g.UseImmediate(index);
+    opcode |= AddressingModeField::encode(kMode_MRI);
+  } else if (TryMatchLoadStoreShift(&g, selector, rep, node, index, &inputs[1],
+                                    &inputs[2])) {
+    input_count = 3;
+    opcode |= AddressingModeField::encode(kMode_Operand2_R_LSL_I);
+  } else {
+    input_count = 2;
+    inputs[1] = g.UseRegister(index);
+    opcode |= AddressingModeField::encode(kMode_MRR);
+  }
+
+  selector->Emit(opcode, arraysize(outputs), outputs, input_count, inputs);
+}
+
+void InstructionSelector::VisitLoad(Node* node) {
+  InstructionCode opcode = kArchNop;
+  ImmediateMode immediate_mode = kNoImmediate;
+  LoadRepresentation load_rep = LoadRepresentationOf(node->op());
+  MachineRepresentation rep = load_rep.representation();
   switch (rep) {
     case MachineRepresentation::kFloat32:
       opcode = kArm64LdrS;
@@ -502,25 +526,7 @@ void InstructionSelector::VisitLoad(Node* node) {
       UNREACHABLE();
       return;
   }
-
-  outputs[0] = g.DefineAsRegister(node);
-  inputs[0] = g.UseRegister(base);
-
-  if (g.CanBeImmediate(index, immediate_mode)) {
-    input_count = 2;
-    inputs[1] = g.UseImmediate(index);
-    opcode |= AddressingModeField::encode(kMode_MRI);
-  } else if (TryMatchLoadStoreShift(&g, this, rep, node, index, &inputs[1],
-                                    &inputs[2])) {
-    input_count = 3;
-    opcode |= AddressingModeField::encode(kMode_Operand2_R_LSL_I);
-  } else {
-    input_count = 2;
-    inputs[1] = g.UseRegister(index);
-    opcode |= AddressingModeField::encode(kMode_MRR);
-  }
-
-  Emit(opcode, arraysize(outputs), outputs, input_count, inputs);
+  EmitLoad(this, node, opcode, immediate_mode, rep);
 }
 
 
@@ -959,7 +965,7 @@ void InstructionSelector::VisitWord64Shl(Node* node) {
   Arm64OperandGenerator g(this);
   Int64BinopMatcher m(node);
   if ((m.left().IsChangeInt32ToInt64() || m.left().IsChangeUint32ToUint64()) &&
-      m.right().IsInRange(32, 63)) {
+      m.right().IsInRange(32, 63) && CanCover(node, m.left().node())) {
     // There's no need to sign/zero-extend to 64-bit if we shift out the upper
     // 32 bits anyway.
     Emit(kArm64Lsl, g.DefineAsRegister(node),
@@ -1563,7 +1569,35 @@ void InstructionSelector::VisitTryTruncateFloat64ToUint64(Node* node) {
 
 
 void InstructionSelector::VisitChangeInt32ToInt64(Node* node) {
-  VisitRR(this, kArm64Sxtw, node);
+  Node* value = node->InputAt(0);
+  if (value->opcode() == IrOpcode::kLoad && CanCover(node, value)) {
+    // Generate sign-extending load.
+    LoadRepresentation load_rep = LoadRepresentationOf(value->op());
+    MachineRepresentation rep = load_rep.representation();
+    InstructionCode opcode = kArchNop;
+    ImmediateMode immediate_mode = kNoImmediate;
+    switch (rep) {
+      case MachineRepresentation::kBit:  // Fall through.
+      case MachineRepresentation::kWord8:
+        opcode = load_rep.IsSigned() ? kArm64Ldrsb : kArm64Ldrb;
+        immediate_mode = kLoadStoreImm8;
+        break;
+      case MachineRepresentation::kWord16:
+        opcode = load_rep.IsSigned() ? kArm64Ldrsh : kArm64Ldrh;
+        immediate_mode = kLoadStoreImm16;
+        break;
+      case MachineRepresentation::kWord32:
+        opcode = kArm64Ldrsw;
+        immediate_mode = kLoadStoreImm32;
+        break;
+      default:
+        UNREACHABLE();
+        return;
+    }
+    EmitLoad(this, value, opcode, immediate_mode, rep, node);
+  } else {
+    VisitRR(this, kArm64Sxtw, node);
+  }
 }
 
 

src/interpreter/interpreter-assembler.cc

@@ -392,6 +392,26 @@ Node* InterpreterAssembler::LoadConstantPoolEntry(Node* index) {
   return Load(MachineType::AnyTagged(), constant_pool, entry_offset);
 }
 
+Node* InterpreterAssembler::LoadAndUntagConstantPoolEntry(Node* index) {
+  Node* constant_pool = LoadObjectField(BytecodeArrayTaggedPointer(),
+                                        BytecodeArray::kConstantPoolOffset);
+  int offset = FixedArray::kHeaderSize - kHeapObjectTag;
+#if V8_TARGET_LITTLE_ENDIAN
+  if (Is64()) {
+    offset += kPointerSize / 2;
+  }
+#endif
+  Node* entry_offset =
+      IntPtrAdd(IntPtrConstant(offset), WordShl(index, kPointerSizeLog2));
+  if (Is64()) {
+    return ChangeInt32ToInt64(
+        Load(MachineType::Int32(), constant_pool, entry_offset));
+  } else {
+    return SmiUntag(
+        Load(MachineType::AnyTagged(), constant_pool, entry_offset));
+  }
+}
+
 Node* InterpreterAssembler::LoadContextSlot(Node* context, int slot_index) {
   return Load(MachineType::AnyTagged(), context,
               IntPtrConstant(Context::SlotOffset(slot_index)));
@@ -927,7 +947,7 @@ Node* InterpreterAssembler::RegisterCount() {
 
 Node* InterpreterAssembler::ExportRegisterFile(Node* array) {
   if (FLAG_debug_code) {
-    Node* array_size = SmiUntag(LoadFixedArrayBaseLength(array));
+    Node* array_size = LoadAndUntagFixedArrayBaseLength(array);
     AbortIfWordNotEqual(
         array_size, RegisterCount(), kInvalidRegisterFileInGenerator);
   }
@@ -962,7 +982,7 @@ Node* InterpreterAssembler::ExportRegisterFile(Node* array) {
 
 Node* InterpreterAssembler::ImportRegisterFile(Node* array) {
   if (FLAG_debug_code) {
-    Node* array_size = SmiUntag(LoadFixedArrayBaseLength(array));
+    Node* array_size = LoadAndUntagFixedArrayBaseLength(array);
     AbortIfWordNotEqual(
         array_size, RegisterCount(), kInvalidRegisterFileInGenerator);
   }

src/interpreter/interpreter-assembler.h

@@ -77,6 +77,9 @@ class InterpreterAssembler : public CodeStubAssembler {
   // Load constant at |index| in the constant pool.
   compiler::Node* LoadConstantPoolEntry(compiler::Node* index);
 
+  // Load and untag constant at |index| in the constant pool.
+  compiler::Node* LoadAndUntagConstantPoolEntry(compiler::Node* index);
+
   // Load |slot_index| from |context|.
   compiler::Node* LoadContextSlot(compiler::Node* context, int slot_index);
   compiler::Node* LoadContextSlot(compiler::Node* context,

src/interpreter/interpreter.cc

@@ -1402,8 +1402,7 @@ void Interpreter::DoJump(InterpreterAssembler* assembler) {
 // Jump by number of bytes in the Smi in the |idx| entry in the constant pool.
 void Interpreter::DoJumpConstant(InterpreterAssembler* assembler) {
   Node* index = __ BytecodeOperandIdx(0);
-  Node* constant = __ LoadConstantPoolEntry(index);
-  Node* relative_jump = __ SmiUntag(constant);
+  Node* relative_jump = __ LoadAndUntagConstantPoolEntry(index);
   __ Jump(relative_jump);
 }
 
@@ -1425,8 +1424,7 @@ void Interpreter::DoJumpIfTrue(InterpreterAssembler* assembler) {
 void Interpreter::DoJumpIfTrueConstant(InterpreterAssembler* assembler) {
   Node* accumulator = __ GetAccumulator();
   Node* index = __ BytecodeOperandIdx(0);
-  Node* constant = __ LoadConstantPoolEntry(index);
-  Node* relative_jump = __ SmiUntag(constant);
+  Node* relative_jump = __ LoadAndUntagConstantPoolEntry(index);
   Node* true_value = __ BooleanConstant(true);
   __ JumpIfWordEqual(accumulator, true_value, relative_jump);
 }
@@ -1449,8 +1447,7 @@ void Interpreter::DoJumpIfFalse(InterpreterAssembler* assembler) {
 void Interpreter::DoJumpIfFalseConstant(InterpreterAssembler* assembler) {
   Node* accumulator = __ GetAccumulator();
   Node* index = __ BytecodeOperandIdx(0);
-  Node* constant = __ LoadConstantPoolEntry(index);
-  Node* relative_jump = __ SmiUntag(constant);
+  Node* relative_jump = __ LoadAndUntagConstantPoolEntry(index);
   Node* false_value = __ BooleanConstant(false);
   __ JumpIfWordEqual(accumulator, false_value, relative_jump);
 }
@@ -1479,8 +1476,7 @@ void Interpreter::DoJumpIfToBooleanTrueConstant(
     InterpreterAssembler* assembler) {
   Node* value = __ GetAccumulator();
   Node* index = __ BytecodeOperandIdx(0);
-  Node* constant = __ LoadConstantPoolEntry(index);
-  Node* relative_jump = __ SmiUntag(constant);
+  Node* relative_jump = __ LoadAndUntagConstantPoolEntry(index);
   Label if_true(assembler), if_false(assembler);
   __ BranchIfToBooleanIsTrue(value, &if_true, &if_false);
   __ Bind(&if_true);
@@ -1513,8 +1509,7 @@ void Interpreter::DoJumpIfToBooleanFalseConstant(
     InterpreterAssembler* assembler) {
   Node* value = __ GetAccumulator();
   Node* index = __ BytecodeOperandIdx(0);
-  Node* constant = __ LoadConstantPoolEntry(index);
-  Node* relative_jump = __ SmiUntag(constant);
+  Node* relative_jump = __ LoadAndUntagConstantPoolEntry(index);
   Label if_true(assembler), if_false(assembler);
   __ BranchIfToBooleanIsTrue(value, &if_true, &if_false);
   __ Bind(&if_true);
@@ -1542,8 +1537,7 @@ void Interpreter::DoJumpIfNullConstant(InterpreterAssembler* assembler) {
   Node* accumulator = __ GetAccumulator();
   Node* null_value = __ HeapConstant(isolate_->factory()->null_value());
   Node* index = __ BytecodeOperandIdx(0);
-  Node* constant = __ LoadConstantPoolEntry(index);
-  Node* relative_jump = __ SmiUntag(constant);
+  Node* relative_jump = __ LoadAndUntagConstantPoolEntry(index);
   __ JumpIfWordEqual(accumulator, null_value, relative_jump);
 }
 
@@ -1568,8 +1562,7 @@ void Interpreter::DoJumpIfUndefinedConstant(InterpreterAssembler* assembler) {
   Node* undefined_value =
       __ HeapConstant(isolate_->factory()->undefined_value());
   Node* index = __ BytecodeOperandIdx(0);
-  Node* constant = __ LoadConstantPoolEntry(index);
-  Node* relative_jump = __ SmiUntag(constant);
+  Node* relative_jump = __ LoadAndUntagConstantPoolEntry(index);
   __ JumpIfWordEqual(accumulator, undefined_value, relative_jump);
 }
 
@@ -1592,8 +1585,7 @@ void Interpreter::DoJumpIfNotHoleConstant(InterpreterAssembler* assembler) {
   Node* accumulator = __ GetAccumulator();
   Node* the_hole_value = __ HeapConstant(isolate_->factory()->the_hole_value());
   Node* index = __ BytecodeOperandIdx(0);
-  Node* constant = __ LoadConstantPoolEntry(index);
-  Node* relative_jump = __ SmiUntag(constant);
+  Node* relative_jump = __ LoadAndUntagConstantPoolEntry(index);
   __ JumpIfWordNotEqual(accumulator, the_hole_value, relative_jump);
 }
 

test/unittests/compiler/arm64/instruction-selector-arm64-unittest.cc

@@ -2396,6 +2396,89 @@ TEST_F(InstructionSelectorTest, ChangeUint32ToUint64AfterLoad) {
   }
 }
 
+TEST_F(InstructionSelectorTest, ChangeInt32ToInt64AfterLoad) {
+  // For each case, test that the conversion is merged into the load
+  // operation.
+  // ChangeInt32ToInt64(Load_Uint8) -> Ldrb
+  {
+    StreamBuilder m(this, MachineType::Int64(), MachineType::Pointer(),
+                    MachineType::Int32());
+    m.Return(m.ChangeInt32ToInt64(
+        m.Load(MachineType::Uint8(), m.Parameter(0), m.Parameter(1))));
+    Stream s = m.Build();
+    ASSERT_EQ(1U, s.size());
+    EXPECT_EQ(kArm64Ldrb, s[0]->arch_opcode());
+    EXPECT_EQ(kMode_MRR, s[0]->addressing_mode());
+    EXPECT_EQ(2U, s[0]->InputCount());
+    EXPECT_EQ(1U, s[0]->OutputCount());
+  }
+  // ChangeInt32ToInt64(Load_Int8) -> Ldrsb
+  {
+    StreamBuilder m(this, MachineType::Int64(), MachineType::Pointer(),
+                    MachineType::Int32());
+    m.Return(m.ChangeInt32ToInt64(
+        m.Load(MachineType::Int8(), m.Parameter(0), m.Parameter(1))));
+    Stream s = m.Build();
+    ASSERT_EQ(1U, s.size());
+    EXPECT_EQ(kArm64Ldrsb, s[0]->arch_opcode());
+    EXPECT_EQ(kMode_MRR, s[0]->addressing_mode());
+    EXPECT_EQ(2U, s[0]->InputCount());
+    EXPECT_EQ(1U, s[0]->OutputCount());
+  }
+  // ChangeInt32ToInt64(Load_Uint16) -> Ldrh
+  {
+    StreamBuilder m(this, MachineType::Int64(), MachineType::Pointer(),
+                    MachineType::Int32());
+    m.Return(m.ChangeInt32ToInt64(
+        m.Load(MachineType::Uint16(), m.Parameter(0), m.Parameter(1))));
+    Stream s = m.Build();
+    ASSERT_EQ(1U, s.size());
+    EXPECT_EQ(kArm64Ldrh, s[0]->arch_opcode());
+    EXPECT_EQ(kMode_MRR, s[0]->addressing_mode());
+    EXPECT_EQ(2U, s[0]->InputCount());
+    EXPECT_EQ(1U, s[0]->OutputCount());
+  }
+  // ChangeInt32ToInt64(Load_Int16) -> Ldrsh
+  {
+    StreamBuilder m(this, MachineType::Int64(), MachineType::Pointer(),
+                    MachineType::Int32());
+    m.Return(m.ChangeInt32ToInt64(
+        m.Load(MachineType::Int16(), m.Parameter(0), m.Parameter(1))));
+    Stream s = m.Build();
+    ASSERT_EQ(1U, s.size());
+    EXPECT_EQ(kArm64Ldrsh, s[0]->arch_opcode());
+    EXPECT_EQ(kMode_MRR, s[0]->addressing_mode());
+    EXPECT_EQ(2U, s[0]->InputCount());
+    EXPECT_EQ(1U, s[0]->OutputCount());
+  }
+  // ChangeInt32ToInt64(Load_Uint32) -> Ldrsw
+  {
+    StreamBuilder m(this, MachineType::Int64(), MachineType::Pointer(),
+                    MachineType::Int32());
+    m.Return(m.ChangeInt32ToInt64(
+        m.Load(MachineType::Uint32(), m.Parameter(0), m.Parameter(1))));
+    Stream s = m.Build();
+    ASSERT_EQ(1U, s.size());
+    EXPECT_EQ(kArm64Ldrsw, s[0]->arch_opcode());
+    EXPECT_EQ(kMode_MRR, s[0]->addressing_mode());
+    EXPECT_EQ(2U, s[0]->InputCount());
+    EXPECT_EQ(1U, s[0]->OutputCount());
+  }
+  // ChangeInt32ToInt64(Load_Int32) -> Ldrsw
+  {
+    StreamBuilder m(this, MachineType::Int64(), MachineType::Pointer(),
+                    MachineType::Int32());
+    m.Return(m.ChangeInt32ToInt64(
+        m.Load(MachineType::Int32(), m.Parameter(0), m.Parameter(1))));
+    Stream s = m.Build();
+    ASSERT_EQ(1U, s.size());
+    EXPECT_EQ(kArm64Ldrsw, s[0]->arch_opcode());
+    EXPECT_EQ(kMode_MRR, s[0]->addressing_mode());
+    EXPECT_EQ(2U, s[0]->InputCount());
+    EXPECT_EQ(1U, s[0]->OutputCount());
+  }
+}
+
 // -----------------------------------------------------------------------------
 // Memory access instructions.