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

Port r11114 (d8c975164).

BUG=
TEST=

Review URL: https://chromiumcodereview.appspot.com/9834044

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11176 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/mips/lithium-codegen-mips.cc

@@ -4512,19 +4512,32 @@ void LCodeGen::EmitDeepCopy(Handle<JSObject> object,
   }
 
 
-  // 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) {
       __ lw(a2, FieldMemOperand(source, i));
       __ sw(a2, FieldMemOperand(result, elements_offset + i));
     }
-  }
 
     // Copy elements backing store content.
-  ASSERT(!has_elements || elements->IsFixedArray());
     int elements_length = has_elements ? elements->length() : 0;
+    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);
+        // We only support little endian mode...
+        int32_t value_low = value & 0xFFFFFFFF;
+        int32_t value_high = value >> 32;
+        int total_offset =
+            elements_offset + FixedDoubleArray::OffsetOfElementAt(i);
+        __ li(a2, Operand(value_low));
+        __ sw(a2, FieldMemOperand(result, total_offset));
+        __ li(a2, Operand(value_high));
+        __ sw(a2, FieldMemOperand(result, total_offset + 4));
+      }
+    } 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);
@@ -4542,6 +4555,10 @@ void LCodeGen::EmitDeepCopy(Handle<JSObject> object,
           __ sw(a2, FieldMemOperand(result, total_offset));
         }
       }
+    } else {
+      UNREACHABLE();
+    }
+  }
 }