PPC: Reland "Add basic crankshaft support for slow-mode for-in to avoid disabling optimizations"

src/ppc/lithium-codegen-ppc.cc

 // Copyright 2014 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/v8.h"
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/cpu-profiler.h"
@@ skipping 6017 matching lines @@
   // If the environment were already registered, we would have no way of
   // backpatching it with the spill slot operands.
   DCHECK(!environment->HasBeenRegistered());
   RegisterEnvironmentForDeoptimization(environment, Safepoint::kNoLazyDeopt);
 
   GenerateOsrPrologue();
 }
 
 
 void LCodeGen::DoForInPrepareMap(LForInPrepareMap* instr) {
-  __ LoadRoot(ip, Heap::kUndefinedValueRootIndex);
-  __ cmp(r3, ip);
-  DeoptimizeIf(eq, instr, Deoptimizer::kUndefined);
-
-  Register null_value = r8;
-  __ LoadRoot(null_value, Heap::kNullValueRootIndex);
-  __ cmp(r3, null_value);
-  DeoptimizeIf(eq, instr, Deoptimizer::kNull);
-
   __ TestIfSmi(r3, r0);
   DeoptimizeIf(eq, instr, Deoptimizer::kSmi, cr0);
 
   STATIC_ASSERT(FIRST_JS_PROXY_TYPE == FIRST_SPEC_OBJECT_TYPE);
   __ CompareObjectType(r3, r4, r4, LAST_JS_PROXY_TYPE);
   DeoptimizeIf(le, instr, Deoptimizer::kWrongInstanceType);
 
   Label use_cache, call_runtime;
+  Register null_value = r8;
+  __ LoadRoot(null_value, Heap::kNullValueRootIndex);
   __ CheckEnumCache(null_value, &call_runtime);
 
   __ LoadP(r3, FieldMemOperand(r3, HeapObject::kMapOffset));
   __ b(&use_cache);
 
   // Get the set of properties to enumerate.
   __ bind(&call_runtime);
   __ push(r3);
   CallRuntime(Runtime::kGetPropertyNamesFast, 1, instr);
 
@@ skipping 117 matching lines @@
   __ Push(scope_info);
   __ push(ToRegister(instr->function()));
   CallRuntime(Runtime::kPushBlockContext, 2, instr);
   RecordSafepoint(Safepoint::kNoLazyDeopt);
 }
 
 
 #undef __
 }
 }  // namespace v8::internal