ARM/ARM64: Optimise HLoadNamedField and HStoreNamedField.

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 1ac579f0f61affe622899924404f0725c5783308..bf13955ccd4de00f18d8b341c3bf6b5959cb7293 100644
--- a/src/arm64/lithium-codegen-arm64.cc
+++ b/src/arm64/lithium-codegen-arm64.cc
@@ -3683,9 +3683,13 @@ void LCodeGen::DoLoadNamedField(LLoadNamedField* instr) {
   if (access.IsInobject()) {
     source = object;
   } else {
-    // Load the properties array, using result as a scratch register.
-    __ Ldr(result, FieldMemOperand(object, JSObject::kPropertiesOffset));
-    source = result;
+    if (instr->object_properties()) {
+      source = ToRegister(instr->object_properties());
+    } else {
+      // Load the properties array, using result as a scratch register.
+      __ Ldr(result, FieldMemOperand(object, JSObject::kPropertiesOffset));
+      source = result;
+    }
   }
 
   if (access.representation().IsSmi() &&
@@ -5393,9 +5397,13 @@ void LCodeGen::DoStoreNamedField(LStoreNamedField* instr) {
   if (access.IsInobject()) {
     destination = object;
   } else {
-    Register temp0 = ToRegister(instr->temp0());
-    __ Ldr(temp0, FieldMemOperand(object, JSObject::kPropertiesOffset));
-    destination = temp0;
+    if (instr->object_properties()) {
+      destination = ToRegister(instr->object_properties());
+    } else {
+      Register temp0 = ToRegister(instr->temp0());
+      __ Ldr(temp0, FieldMemOperand(object, JSObject::kPropertiesOffset));
+      destination = temp0;
+    }
   }
 
   if (representation.IsSmi() &&