Small parseInt optimizations

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 3367 matching lines @@
     i += step;
   }
   return destination;
 }
 
 
 static Object* Runtime_StringParseInt(Arguments args) {
   NoHandleAllocation ha;
 
   CONVERT_CHECKED(String, s, args[0]);
-  CONVERT_DOUBLE_CHECKED(n, args[1]);
-  int radix = FastD2I(n);
+  CONVERT_SMI_CHECKED(radix, args[1]);
 
   s->TryFlattenIfNotFlat();
 
   int len = s->length();
   int i;
 
   // Skip leading white space.
   for (i = 0; i < len && Scanner::kIsWhiteSpace.get(s->Get(i)); i++) ;
   if (i == len) return Heap::nan_value();
 
@@ skipping 4502 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