[runtime] Remove useless %_IsUndetectableObject intrinsic.

src/full-codegen/mips/full-codegen-mips.cc

 // Copyright 2012 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.
 
 #if V8_TARGET_ARCH_MIPS
 
 // Note on Mips implementation:
 //
 // The result_register() for mips is the 'v0' register, which is defined
 // by the ABI to contain function return values. However, the first
@@ skipping 3420 matching lines @@
 
   __ JumpIfSmi(v0, if_false);
   __ GetObjectType(v0, a1, a1);
   PrepareForBailoutBeforeSplit(expr, true, if_true, if_false);
   Split(eq, a1, Operand(SIMD128_VALUE_TYPE), if_true, if_false, fall_through);
 
   context()->Plug(if_true, if_false);
 }
 
 
-void FullCodeGenerator::EmitIsUndetectableObject(CallRuntime* expr) {
-  ZoneList<Expression*>* args = expr->arguments();
-  DCHECK(args->length() == 1);
-
-  VisitForAccumulatorValue(args->at(0));
-
-  Label materialize_true, materialize_false;
-  Label* if_true = NULL;
-  Label* if_false = NULL;
-  Label* fall_through = NULL;
-  context()->PrepareTest(&materialize_true, &materialize_false,
-                         &if_true, &if_false, &fall_through);
-
-  __ JumpIfSmi(v0, if_false);
-  __ lw(a1, FieldMemOperand(v0, HeapObject::kMapOffset));
-  __ lbu(a1, FieldMemOperand(a1, Map::kBitFieldOffset));
-  PrepareForBailoutBeforeSplit(expr, true, if_true, if_false);
-  __ And(at, a1, Operand(1 << Map::kIsUndetectable));
-  Split(ne, at, Operand(zero_reg), if_true, if_false, fall_through);
-
-  context()->Plug(if_true, if_false);
-}
-
-
 void FullCodeGenerator::EmitIsStringWrapperSafeForDefaultValueOf(
     CallRuntime* expr) {
   ZoneList<Expression*>* args = expr->arguments();
   DCHECK(args->length() == 1);
 
   VisitForAccumulatorValue(args->at(0));
 
   Label materialize_true, materialize_false, skip_lookup;
   Label* if_true = NULL;
   Label* if_false = NULL;
@@ skipping 1925 matching lines @@
          reinterpret_cast<uint32_t>(
              isolate->builtins()->OsrAfterStackCheck()->entry()));
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_MIPS