Reland "In-object double fields unboxing (for 64-bit only)."

src/x64/lithium-codegen-x64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
@@ skipping 2958 matching lines @@
       __ load_rax(ToExternalReference(LConstantOperand::cast(instr->object())));
     } else {
       Register object = ToRegister(instr->object());
       __ Load(result, MemOperand(object, offset), access.representation());
     }
     return;
   }
 
   Register object = ToRegister(instr->object());
   if (instr->hydrogen()->representation().IsDouble()) {
+    DCHECK(access.IsInobject());
     XMMRegister result = ToDoubleRegister(instr->result());
     __ movsd(result, FieldOperand(object, offset));
     return;
   }
 
   Register result = ToRegister(instr->result());
   if (!access.IsInobject()) {
     __ movp(result, FieldOperand(object, JSObject::kPropertiesOffset));
     object = result;
   }
@@ skipping 1126 matching lines @@
     }
     return;
   }
 
   Register object = ToRegister(instr->object());
   __ AssertNotSmi(object);
 
   DCHECK(!representation.IsSmi() ||
          !instr->value()->IsConstantOperand() ||
          IsInteger32Constant(LConstantOperand::cast(instr->value())));
-  if (representation.IsDouble()) {
+  if (!FLAG_unbox_double_fields && representation.IsDouble()) {
     DCHECK(access.IsInobject());
     DCHECK(!hinstr->has_transition());
     DCHECK(!hinstr->NeedsWriteBarrier());
     XMMRegister value = ToDoubleRegister(instr->value());
     __ movsd(FieldOperand(object, offset), value);
     return;
   }
 
   if (hinstr->has_transition()) {
     Handle<Map> transition = hinstr->transition_map();
@@ skipping 29 matching lines @@
     }
     // Store int value directly to upper half of the smi.
     STATIC_ASSERT(kSmiTag == 0);
     DCHECK(kSmiTagSize + kSmiShiftSize == 32);
     offset += kPointerSize / 2;
     representation = Representation::Integer32();
   }
 
   Operand operand = FieldOperand(write_register, offset);
 
-  if (instr->value()->IsRegister()) {
+  if (FLAG_unbox_double_fields && representation.IsDouble()) {
+    DCHECK(access.IsInobject());
+    XMMRegister value = ToDoubleRegister(instr->value());
+    __ movsd(operand, value);
+
+  } else if (instr->value()->IsRegister()) {
     Register value = ToRegister(instr->value());
     __ Store(operand, value, representation);
   } else {
     LConstantOperand* operand_value = LConstantOperand::cast(instr->value());
     if (IsInteger32Constant(operand_value)) {
       DCHECK(!hinstr->NeedsWriteBarrier());
       int32_t value = ToInteger32(operand_value);
       if (representation.IsSmi()) {
         __ Move(operand, Smi::FromInt(value));
 
@@ skipping 1697 matching lines @@
   CallRuntime(Runtime::kPushBlockContext, 2, instr);
   RecordSafepoint(Safepoint::kNoLazyDeopt);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64