First implementation of fast path for instantiation of array literals composed of doubles.

src/x64/lithium-codegen-x64.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 4211 matching lines @@
       EmitDeepCopy(value_object, result, source, offset);
     } else if (value->IsHeapObject()) {
       __ LoadHeapObject(rcx, Handle<HeapObject>::cast(value));
       __ movq(FieldOperand(result, total_offset), rcx);
     } else {
       __ movq(rcx, value, RelocInfo::NONE);
       __ movq(FieldOperand(result, total_offset), rcx);
     }
   }
 
-  // Copy elements backing store header.
-  ASSERT(!has_elements || elements->IsFixedArray());
   if (has_elements) {
+    // Copy elements backing store header.
     __ LoadHeapObject(source, elements);
     for (int i = 0; i < FixedArray::kHeaderSize; i += kPointerSize) {
       __ movq(rcx, FieldOperand(source, i));
       __ movq(FieldOperand(result, elements_offset + i), rcx);
     }
-  }
 
-  // Copy elements backing store content.
-  ASSERT(!has_elements || elements->IsFixedArray());
-  int elements_length = has_elements ? elements->length() : 0;
-  for (int i = 0; i < elements_length; i++) {
-    int total_offset = elements_offset + FixedArray::OffsetOfElementAt(i);
-    Handle<Object> value = JSObject::GetElement(object, i);
-    if (value->IsJSObject()) {
-      Handle<JSObject> value_object = Handle<JSObject>::cast(value);
-      __ lea(rcx, Operand(result, *offset));
-      __ movq(FieldOperand(result, total_offset), rcx);
-      __ LoadHeapObject(source, value_object);
-      EmitDeepCopy(value_object, result, source, offset);
-    } else if (value->IsHeapObject()) {
-      __ LoadHeapObject(rcx, Handle<HeapObject>::cast(value));
-      __ movq(FieldOperand(result, total_offset), rcx);
+    // Copy elements backing store content.
+    int elements_length = elements->length();
+    if (elements->IsFixedDoubleArray()) {
+      Handle<FixedDoubleArray> double_array =
+          Handle<FixedDoubleArray>::cast(elements);
+      for (int i = 0; i < elements_length; i++) {
+        int64_t value = double_array->get_representation(i);
+        int total_offset =
+            elements_offset + FixedDoubleArray::OffsetOfElementAt(i);
+        __ movq(rcx, value, RelocInfo::NONE);
+        __ movq(FieldOperand(result, total_offset), rcx);
+      }
+    } else if (elements->IsFixedArray()) {
+      for (int i = 0; i < elements_length; i++) {
+        int total_offset = elements_offset + FixedArray::OffsetOfElementAt(i);
+        Handle<Object> value = JSObject::GetElement(object, i);
+        if (value->IsJSObject()) {
+          Handle<JSObject> value_object = Handle<JSObject>::cast(value);
+          __ lea(rcx, Operand(result, *offset));
+          __ movq(FieldOperand(result, total_offset), rcx);
+          __ LoadHeapObject(source, value_object);
+          EmitDeepCopy(value_object, result, source, offset);
+        } else if (value->IsHeapObject()) {
+          __ LoadHeapObject(rcx, Handle<HeapObject>::cast(value));
+          __ movq(FieldOperand(result, total_offset), rcx);
+        } else {
+          __ movq(rcx, value, RelocInfo::NONE);
+          __ movq(FieldOperand(result, total_offset), rcx);
+        }
+      }
     } else {
-      __ movq(rcx, value, RelocInfo::NONE);
-      __ movq(FieldOperand(result, total_offset), rcx);
+      UNREACHABLE();
     }
   }
 }
 
 
 void LCodeGen::DoFastLiteral(LFastLiteral* instr) {
   int size = instr->hydrogen()->total_size();
 
   // Allocate all objects that are part of the literal in one big
   // allocation. This avoids multiple limit checks.
@@ skipping 472 matching lines @@
                                FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64