PPC: Only swap undefined for the global object if necessary in the prologue

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 100 matching lines @@
     // r4: Callee's JS function.
     // cp: Callee's context.
     // pp: Callee's constant pool pointer (if enabled)
     // fp: Caller's frame pointer.
     // lr: Caller's pc.
     // ip: Our own function entry (required by the prologue)
 
     // Sloppy mode functions and builtins need to replace the receiver with the
     // global proxy when called as functions (without an explicit receiver
     // object).
-    if (graph()->this_has_uses() && is_sloppy(info_->language_mode()) &&
+    if (is_sloppy(info_->language_mode()) && info()->MayUseThis() &&
         !info_->is_native()) {
       Label ok;
       int receiver_offset = info_->scope()->num_parameters() * kPointerSize;
       __ LoadP(r5, MemOperand(sp, receiver_offset));
       __ CompareRoot(r5, Heap::kUndefinedValueRootIndex);
       __ bne(&ok);
 
       __ LoadP(r5, GlobalObjectOperand());
       __ LoadP(r5, FieldMemOperand(r5, GlobalObject::kGlobalProxyOffset));
 
@@ skipping 6073 matching lines @@
   __ Push(scope_info);
   __ push(ToRegister(instr->function()));
   CallRuntime(Runtime::kPushBlockContext, 2, instr);
   RecordSafepoint(Safepoint::kNoLazyDeopt);
 }
 
 
 #undef __
 }
 }  // namespace v8::internal