[stubs] Use CSA::IsHeapNumberMap() instead of manual map comparing.

src/builtins/builtins-string.cc

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/builtins/builtins.h"
 #include "src/builtins/builtins-utils.h"
 
 #include "src/code-factory.h"
 #include "src/regexp/regexp-utils.h"
 
@@ skipping 1013 matching lines @@
       a.GotoUnless(a.SmiLessThanOrEqual(var_length.value(), zero), &out);
       a.Return(a.EmptyStringConstant());
     }
 
     a.Bind(&if_isheapnumber);
     {
       // If {length} is a heap number, it is definitely out of bounds. There are
       // two cases according to the spec: if it is negative, "" is returned; if
       // it is positive, then length is set to {string_length} - {start}.
 
-      CSA_ASSERT(&a, a.WordEqual(a.LoadMap(var_length.value()),
-                                 a.HeapNumberMapConstant()));
+      CSA_ASSERT(&a, a.IsHeapNumberMap(a.LoadMap(var_length.value())));
 
       Label if_isnegative(&a), if_ispositive(&a);
       Node* const float_zero = a.Float64Constant(0.);
       Node* const length_float = a.LoadHeapNumberValue(var_length.value());
       a.Branch(a.Float64LessThan(length_float, float_zero), &if_isnegative,
                &if_ispositive);
 
       a.Bind(&if_isnegative);
       a.Return(a.EmptyStringConstant());
 
@@ skipping 48 matching lines @@
     {
       Node* const zero = a->SmiConstant(Smi::kZero);
       var_result.Bind(a->Select(a->SmiLessThan(value_int, zero), zero, limit));
       a->Goto(&out);
     }
   }
 
   a->Bind(&if_isnotsmi);
   {
     // {value} is a heap number - in this case, it is definitely out of bounds.
-    CSA_ASSERT(a,
-               a->WordEqual(a->LoadMap(value_int), a->HeapNumberMapConstant()));
+    CSA_ASSERT(a, a->IsHeapNumberMap(a->LoadMap(value_int)));
 
     Node* const float_zero = a->Float64Constant(0.);
     Node* const smi_zero = a->SmiConstant(Smi::kZero);
     Node* const value_float = a->LoadHeapNumberValue(value_int);
     var_result.Bind(a->Select(a->Float64LessThan(value_float, float_zero),
                               smi_zero, limit));
     a->Goto(&out);
   }
 
   a->Bind(&out);
@@ skipping 350 matching lines @@
         Runtime::kThrowIncompatibleMethodReceiver, context,
         assembler.HeapConstant(assembler.factory()->NewStringFromAsciiChecked(
             "String Iterator.prototype.next", TENURED)),
         iterator);
     assembler.Return(result);  // Never reached.
   }
 }
 
 }  // namespace internal
 }  // namespace v8