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

src/ia32/full-codegen-ia32.cc

Index: src/ia32/full-codegen-ia32.cc
diff --git a/src/ia32/full-codegen-ia32.cc b/src/ia32/full-codegen-ia32.cc
index 6c38b70e5464d4552574034b20008f8837796166..703330142e12aa3b00f90b63f42aa9f6cfc01749 100644
--- a/src/ia32/full-codegen-ia32.cc
+++ b/src/ia32/full-codegen-ia32.cc
@@ -114,7 +114,8 @@ void FullCodeGenerator::Generate() {
   // Sloppy mode functions and builtins need to replace the receiver with the
   // global proxy when called as functions (without an explicit receiver
   // object).
-  if (is_sloppy(info->language_mode()) && !info->is_native()) {
+  if (is_sloppy(info->language_mode()) && !info->is_native() &&
+      info->MayUseThis()) {
     Label ok;
     // +1 for return address.
     int receiver_offset = (info->scope()->num_parameters() + 1) * kPointerSize;