Reverting 2768.

src/ia32/codegen-ia32.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 6929 matching lines @@
       UNREACHABLE();
   }
 }
 
 
 void FloatingPointHelper::AllocateHeapNumber(MacroAssembler* masm,
                                              Label* need_gc,
                                              Register scratch1,
                                              Register scratch2,
                                              Register result) {
-  // Allocate heap number in new space.
-  __ AllocateObjectInNewSpace(HeapNumber::kSize,
-                              result,
-                              scratch1,
-                              scratch2,
-                              need_gc,
-                              false);
-  
-  // Set the map and tag the result.
+  ExternalReference allocation_top =
+      ExternalReference::new_space_allocation_top_address();
+  ExternalReference allocation_limit =
+      ExternalReference::new_space_allocation_limit_address();
+  __ mov(Operand(scratch1), Immediate(allocation_top));
+  __ mov(result, Operand(scratch1, 0));
+  __ lea(scratch2, Operand(result, HeapNumber::kSize));  // scratch2: new top
+  __ cmp(scratch2, Operand::StaticVariable(allocation_limit));
+  __ j(above, need_gc, not_taken);
+
+  __ mov(Operand(scratch1, 0), scratch2);  // store new top
   __ mov(Operand(result, HeapObject::kMapOffset),
          Immediate(Factory::heap_number_map()));
-  __ or_(Operand(result), Immediate(kHeapObjectTag));
+  // Tag old top and use as result.
+  __ add(Operand(result), Immediate(kHeapObjectTag));
 }
 
 
 void FloatingPointHelper::LoadFloatOperand(MacroAssembler* masm,
                                            Register number) {
   Label load_smi, done;
 
   __ test(number, Immediate(kSmiTagMask));
   __ j(zero, &load_smi, not_taken);
   __ fld_d(FieldOperand(number, HeapNumber::kValueOffset));
@@ skipping 897 matching lines @@
 
 int CompareStub::MinorKey() {
   // Encode the two parameters in a unique 16 bit value.
   ASSERT(static_cast<unsigned>(cc_) < (1 << 15));
   return (static_cast<unsigned>(cc_) << 1) | (strict_ ? 1 : 0);
 }
 
 #undef __
 
 } }  // namespace v8::internal