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

src/arm64/lithium-codegen-arm64.cc

Index: src/arm64/lithium-codegen-arm64.cc
diff --git a/src/arm64/lithium-codegen-arm64.cc b/src/arm64/lithium-codegen-arm64.cc
index 9fe311c939277109a7348a5b7ff48cc4770f31c1..8129470e158cfa719501209d5fa601f20646e56b 100644
--- a/src/arm64/lithium-codegen-arm64.cc
+++ b/src/arm64/lithium-codegen-arm64.cc
@@ -3660,6 +3660,7 @@ void LCodeGen::DoLoadNamedField(LLoadNamedField* instr) {
   }
 
   if (instr->hydrogen()->representation().IsDouble()) {
+    DCHECK(access.IsInobject());
     FPRegister result = ToDoubleRegister(instr->result());
     __ Ldr(result, FieldMemOperand(object, offset));
     return;
@@ -5350,7 +5351,7 @@ void LCodeGen::DoStoreNamedField(LStoreNamedField* instr) {
 
   __ AssertNotSmi(object);
 
-  if (representation.IsDouble()) {
+  if (!FLAG_unbox_double_fields && representation.IsDouble()) {
     DCHECK(access.IsInobject());
     DCHECK(!instr->hydrogen()->has_transition());
     DCHECK(!instr->hydrogen()->NeedsWriteBarrier());
@@ -5359,8 +5360,6 @@ void LCodeGen::DoStoreNamedField(LStoreNamedField* instr) {
     return;
   }
 
-  Register value = ToRegister(instr->value());
-
   DCHECK(!representation.IsSmi() ||
          !instr->value()->IsConstantOperand() ||
          IsInteger32Constant(LConstantOperand::cast(instr->value())));
@@ -5392,8 +5391,12 @@ void LCodeGen::DoStoreNamedField(LStoreNamedField* instr) {
     destination = temp0;
   }
 
-  if (representation.IsSmi() &&
-     instr->hydrogen()->value()->representation().IsInteger32()) {
+  if (FLAG_unbox_double_fields && representation.IsDouble()) {
+    DCHECK(access.IsInobject());
+    FPRegister value = ToDoubleRegister(instr->value());
+    __ Str(value, FieldMemOperand(object, offset));
+  } else if (representation.IsSmi() &&
+             instr->hydrogen()->value()->representation().IsInteger32()) {
     DCHECK(instr->hydrogen()->store_mode() == STORE_TO_INITIALIZED_ENTRY);
 #ifdef DEBUG
     Register temp0 = ToRegister(instr->temp0());
@@ -5408,12 +5411,15 @@ void LCodeGen::DoStoreNamedField(LStoreNamedField* instr) {
 #endif
     STATIC_ASSERT(static_cast<unsigned>(kSmiValueSize) == kWRegSizeInBits);
     STATIC_ASSERT(kSmiTag == 0);
+    Register value = ToRegister(instr->value());
     __ Store(value, UntagSmiFieldMemOperand(destination, offset),
              Representation::Integer32());
   } else {
+    Register value = ToRegister(instr->value());
     __ Store(value, FieldMemOperand(destination, offset), representation);
   }
   if (instr->hydrogen()->NeedsWriteBarrier()) {
+    Register value = ToRegister(instr->value());
     __ RecordWriteField(destination,
                         offset,
                         value,                        // Clobbered.