Use a BOP for Hash#default

On a hash miss we need to call default if it is redefined in order to
return the default value to be used. Previously we checked this with
rb_method_basic_definition_p, which avoids the method call but requires
a method lookup.

This commit replaces the previous check with BASIC_OP_UNREDEFINED_P and
a new BOP_DEFAULT. We still need to fall back to
rb_method_basic_definition_p when called on a subclasss of hash.

    |                |compare-ruby|built-ruby|
    |:---------------|-----------:|---------:|
    |hash_aref_miss  |       2.692|     3.531|
    |                |           -|     1.31x|

Co-authored-by: Daniel Colson <danieljamescolson@gmail.com>
Co-authored-by: "Ian C. Anderson" <ian@iancanderson.com>
Co-authored-by: Jack McCracken <me@jackmc.xyz>

1 files changed, 1 insertions, 0 deletions

diff --git a/vm.c b/vm.c
index 8daed5d474..2821f58adb 100644
--- a/vm.c
+++ b/vm.c
@@ -2054,6 +2054,7 @@ vm_init_redefined_flag(void)
     OP(Or, OR), (C(Integer));
     OP(NilP, NIL_P), (C(NilClass));
     OP(Cmp, CMP), (C(Integer), C(Float), C(String));
+    OP(Default, DEFAULT), (C(Hash));
 #undef C
 #undef OP
 }