Add number allocation call to runtime.cc instead of misusing

src/x64/full-codegen-x64.cc

 // Copyright 2010 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 2225 matching lines @@
 void FullCodeGenerator::EmitRandomHeapNumber(ZoneList<Expression*>* args) {
   ASSERT(args->length() == 0);
 
   Label slow_allocate_heapnumber;
   Label heapnumber_allocated;
 
   __ AllocateHeapNumber(rbx, rcx, &slow_allocate_heapnumber);
   __ jmp(&heapnumber_allocated);
 
   __ bind(&slow_allocate_heapnumber);
-  // To allocate a heap number, and ensure that it is not a smi, we
-  // call the runtime function FUnaryMinus on 0, returning the double
-  // -0.0.  A new, distinct heap number is returned each time.
-  __ Push(Smi::FromInt(0));
-  __ CallRuntime(Runtime::kNumberUnaryMinus, 1);
+  // Allocate a heap number.
+  __ CallRuntime(Runtime::kNumberAlloc, 0);
   __ movq(rbx, rax);
 
   __ bind(&heapnumber_allocated);
 
   // Return a random uint32 number in rax.
   // The fresh HeapNumber is in rbx, which is callee-save on both x64 ABIs.
   __ PrepareCallCFunction(0);
   __ CallCFunction(ExternalReference::random_uint32_function(), 0);
 
   // Convert 32 random bits in rax to 0.(32 random bits) in a double
@@ skipping 984 matching lines @@
   __ ret(0);
 }
 
 
 #undef __
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64