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

src/arm/lithium-codegen-arm.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.
 
 #include "src/v8.h"
 
 #include "src/arm/lithium-codegen-arm.h"
 #include "src/arm/lithium-gap-resolver-arm.h"
 #include "src/base/bits.h"
 #include "src/code-factory.h"
@@ skipping 102 matching lines @@
 
     // r1: Callee's JS function.
     // cp: Callee's context.
     // pp: Callee's constant pool pointer (if FLAG_enable_ool_constant_pool)
     // fp: Caller's frame pointer.
     // lr: Caller's pc.
 
     // 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;
       __ ldr(r2, MemOperand(sp, receiver_offset));
       __ CompareRoot(r2, Heap::kUndefinedValueRootIndex);
       __ b(ne, &ok);
 
       __ ldr(r2, GlobalObjectOperand());
       __ ldr(r2, FieldMemOperand(r2, GlobalObject::kGlobalProxyOffset));
 
@@ skipping 5809 matching lines @@
   __ Push(scope_info);
   __ push(ToRegister(instr->function()));
   CallRuntime(Runtime::kPushBlockContext, 2, instr);
   RecordSafepoint(Safepoint::kNoLazyDeopt);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal