diff -r 50fdb38839eb -r 41b780b43b74 src/cpu/x86/vm/globals_x86.hpp
--- a/src/cpu/x86/vm/globals_x86.hpp	Tue Nov 26 18:38:19 2013 -0800
+++ b/src/cpu/x86/vm/globals_x86.hpp	Wed Nov 27 16:16:21 2013 -0800
@@ -37,7 +37,8 @@
 define_pd_global(bool, NeedsDeoptSuspend,        false); // only register window machines need this
 
 define_pd_global(bool, ImplicitNullChecks,       true);  // Generate code for implicit null checks
-define_pd_global(bool, UncommonNullCast,         true);  // Uncommon-trap NULLs past to check cast
+define_pd_global(bool, TrapBasedNullChecks,      false); // Not needed on x86.
+define_pd_global(bool, UncommonNullCast,         true);  // Uncommon-trap NULLs passed to check cast
 
 // See 4827828 for this change. There is no globals_core_i486.hpp. I can't
 // assign a different value for C2 without touching a number of files. Use