Clean up after r16292 (disable optimization for StringWrappers).

src/x64/full-codegen-x64.cc

Index: src/x64/full-codegen-x64.cc
diff --git a/src/x64/full-codegen-x64.cc b/src/x64/full-codegen-x64.cc
index 9f2074c58c435921e8ef9295f90ca28df69a12bc..6145e130d812e56df6a8299a43a36ce0f7027e49 100644
--- a/src/x64/full-codegen-x64.cc
+++ b/src/x64/full-codegen-x64.cc
@@ -2937,7 +2937,7 @@ void FullCodeGenerator::EmitIsStringWrapperSafeForDefaultValueOf(
 
   VisitForAccumulatorValue(args->at(0));
 
-  Label materialize_true, materialize_false;
+  Label materialize_true, materialize_false, skip_lookup;
   Label* if_true = NULL;
   Label* if_false = NULL;
   Label* fall_through = NULL;
@@ -2951,7 +2951,7 @@ void FullCodeGenerator::EmitIsStringWrapperSafeForDefaultValueOf(
   __ movq(rbx, FieldOperand(rax, HeapObject::kMapOffset));
   __ testb(FieldOperand(rbx, Map::kBitField2Offset),
            Immediate(1 << Map::kStringWrapperSafeForDefaultValueOf));
-  __ j(not_zero, if_true);
+  __ j(not_zero, &skip_lookup);
 
   // Check for fast case object. Generate false result for slow case object.
   __ movq(rcx, FieldOperand(rax, JSObject::kPropertiesOffset));
@@ -2993,9 +2993,16 @@ void FullCodeGenerator::EmitIsStringWrapperSafeForDefaultValueOf(
   __ j(not_equal, &loop);
 
   __ bind(&done);
+
+  // Set the bit in the map to indicate that there is no local valueOf field.
+  __ or_(FieldOperand(rbx, Map::kBitField2Offset),
+         Immediate(1 << Map::kStringWrapperSafeForDefaultValueOf));
+
   // Reload map as register rbx was used as temporary above.
   __ movq(rbx, FieldOperand(rax, HeapObject::kMapOffset));
 
+  __ bind(&skip_lookup);
+
   // If a valueOf property is not found on the object check that its
   // prototype is the un-modified String prototype. If not result is false.
   __ movq(rcx, FieldOperand(rbx, Map::kPrototypeOffset));
@@ -3006,10 +3013,9 @@ void FullCodeGenerator::EmitIsStringWrapperSafeForDefaultValueOf(
   __ movq(rdx, FieldOperand(rdx, GlobalObject::kNativeContextOffset));
   __ cmpq(rcx,
           ContextOperand(rdx, Context::STRING_FUNCTION_PROTOTYPE_MAP_INDEX));
-  __ j(not_equal, if_false);
-  __ jmp(if_true);
-
   PrepareForBailoutBeforeSplit(expr, true, if_true, if_false);
+  Split(equal, if_true, if_false, fall_through);
+
   context()->Plug(if_true, if_false);
 }