Optimize 3 Number2Integer functions in runtime.cc: remove the check that was ...

src/runtime.cc

 // Copyright 2006-2009 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 4134 matching lines @@
   RUNTIME_ASSERT(number->IsNumber());
 
   return Heap::NumberToString(number);
 }
 
 
 static Object* Runtime_NumberToInteger(Arguments args) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 1);
 
-  Object* obj = args[0];
-  if (obj->IsSmi()) return obj;
-  CONVERT_DOUBLE_CHECKED(number, obj);
-  return Heap::NumberFromDouble(DoubleToInteger(number));
+  CONVERT_DOUBLE_CHECKED(number, args[0]);
+
+  // We do not include 0 so that we didn't have to treat +0 / -0 cases.

[Mads Ager (chromium), 2010/02/25 15:11:03]

didn't -> don't

[Oleg Eterevsky, 2010/02/25 15:30:43]

Done.

+  if (number > 0 && number <= Smi::kMaxValue)

[Mads Ager (chromium), 2010/02/25 15:11:03]

Please use braces around both the if and the else body.

if (...) {
  ...
} else {
  ...
}

[Oleg Eterevsky, 2010/02/25 15:30:43]

Done.

+    return Smi::FromInt(static_cast<int>(number));
+  else
+    return Heap::NumberFromDouble(DoubleToInteger(number));
 }
 
 
 static Object* Runtime_NumberToJSUint32(Arguments args) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 1);
 
   Object* obj = args[0];

[Mads Ager (chromium), 2010/02/25 15:11:03]

Just use args[0] in the CONVERT_NUMBER_CHECKED below?

[Oleg Eterevsky, 2010/02/25 15:30:43]

Done.

-  if (obj->IsSmi() && Smi::cast(obj)->value() >= 0) return obj;
   CONVERT_NUMBER_CHECKED(int32_t, number, Uint32, obj);
   return Heap::NumberFromUint32(number);
 }
 
 
 static Object* Runtime_NumberToJSInt32(Arguments args) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 1);
 
-  Object* obj = args[0];
-  if (obj->IsSmi()) return obj;
-  CONVERT_DOUBLE_CHECKED(number, obj);
-  return Heap::NumberFromInt32(DoubleToInt32(number));
+  CONVERT_DOUBLE_CHECKED(number, args[0]);
+  if (number > 0 && number <= Smi::kMaxValue)

[Mads Ager (chromium), 2010/02/25 15:11:03]

Please use braces here as well.  Repeat the comment about not handling 0 because
of the -0/+0 complications?

[Oleg Eterevsky, 2010/02/25 15:30:43]

Done.

+    return Smi::FromInt(static_cast<int>(number));
+  else
+    return Heap::NumberFromInt32(DoubleToInt32(number));
 }
 
 
 // Converts a Number to a Smi, if possible. Returns NaN if the number is not
 // a small integer.
 static Object* Runtime_NumberToSmi(Arguments args) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 1);
 
   Object* obj = args[0];
@@ skipping 4088 matching lines @@
   } else {
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     Counters::gc_last_resort_from_js.Increment();
     Heap::CollectAllGarbage(false);
   }
 }
 
 
 } }  // namespace v8::internal