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

src/x87/lithium-codegen-x87.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"
 
 #if V8_TARGET_ARCH_X87
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
@@ skipping 92 matching lines @@
 #ifdef DEBUG
     if (strlen(FLAG_stop_at) > 0 &&
         info_->function()->name()->IsUtf8EqualTo(CStrVector(FLAG_stop_at))) {
       __ int3();
     }
 #endif
 
     // 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;
       // +1 for return address.
       int receiver_offset = (scope()->num_parameters() + 1) * kPointerSize;
       __ mov(ecx, Operand(esp, receiver_offset));
 
       __ cmp(ecx, isolate()->factory()->undefined_value());
       __ j(not_equal, &ok, Label::kNear);
 
       __ mov(ecx, GlobalObjectOperand());
@@ skipping 6251 matching lines @@
   CallRuntime(Runtime::kPushBlockContext, 2, instr);
   RecordSafepoint(Safepoint::kNoLazyDeopt);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X87