Add GV_NOUNIVERSAL flag to skip UNIVERSAL lookup

For the `isa` infix operator, we can fall back to `sv_derived_from_sv`
instead of looking up UNIVERSAL::isa. Passing GV_NOUNIVERSAL will tell
gv_fetchmeth_internal not to look at UNIVERSAL for the method, and instead
return NULL. Then `Perl_sv_isa_sv` will skip the if block and check
`sv_derived_from_sv` which does the same thing UNIVERSAL::isa would have done.

1 files changed, 1 insertions, 0 deletions

diff --git a/gv.h b/gv.h
index 514bac1871..9b465a069d 100644
--- a/gv.h
+++ b/gv.h
@@ -245,6 +245,7 @@ Return the CV from the GV.
 
 /* Flags for gv_fetchmeth_pvn and gv_autoload_pvn*/
 #define GV_SUPER	0x1000	/* SUPER::method */
+#define GV_NOUNIVERSAL  0x2000  /* Skip UNIVERSAL lookup */
 
 /* Flags for gv_autoload_*/
 #define GV_AUTOLOAD_ISMETHOD 1	/* autoloading a method? */