Move the is_pregenerated flag so it does not overlap other flags.

src/x64/code-stubs-x64.cc

Index: src/x64/code-stubs-x64.cc
===================================================================
--- src/x64/code-stubs-x64.cc	(revision 9462)
+++ src/x64/code-stubs-x64.cc	(working copy)
@@ -3370,13 +3370,16 @@
 
 
 bool CEntryStub::IsPregenerated() {
+#ifdef _WIN64
   return result_size_ == 1;
+#else
+  return true;
+#endif
 }
 
 
 void CodeStub::GenerateStubsAheadOfTime() {
-  CEntryStub save_doubles(1, kSaveFPRegs);
-  save_doubles.GetCode()->set_is_pregenerated(true);
+  CEntryStub::GenerateFixedRegStubsAheadOfTime();
   StoreBufferOverflowStub::GenerateFixedRegStubsAheadOfTime();
   // It is important that the store buffer overflow stubs are generated first.
   RecordWriteStub::GenerateFixedRegStubsAheadOfTime();
@@ -3387,6 +3390,14 @@
 }
 
 
+void CEntryStub::GenerateFixedRegStubsAheadOfTime() {
+  CEntryStub stub(1, kDontSaveFPRegs);
+  stub.GetCode()->set_is_pregenerated(true);
+  CEntryStub save_doubles(1, kSaveFPRegs);
+  save_doubles.GetCode()->set_is_pregenerated(true);
+}
+
+
 void CEntryStub::GenerateThrowTOS(MacroAssembler* masm) {
   // Throw exception in eax.
   __ Throw(rax);