diff --git a/perl.h b/perl.h
index 1257a5595144..4ef161db95b4 100644
--- a/perl.h
+++ b/perl.h
@@ -6365,7 +6365,7 @@ EXTCONST U8   PL_deBruijn_bitpos_tab64[];
 #ifdef USE_PERL_SWITCH_LOCALE_CONTEXT
 #  define PERL_SET_LOCALE_CONTEXT(i)                                        \
       STMT_START {                                                          \
-          if (LIKELY(! PL_veto_switch_non_tTHX_context))                    \
+          if (UNLIKELY(PL_veto_switch_non_tTHX_context))                    \
                 Perl_switch_locale_context();                               \
       } STMT_END
 #else