Optimize &defined as a builtin

perf/hashmark.pl

@@ -1,20 +1,20 @@
 # vim: ft=perl6
 sub _exists_key(\$container, $key) {
-    $container.defined ?? $container.exists-key($key) !! False
+    defined($container) ?? $container.exists-key($key) !! False
 }
 sub _delete_key(\$container, $key) {
-    $container.defined ?? $container.delete-key($key) !! Any
+    defined($container) ?? $container.delete-key($key) !! Any
 }
 sub _at_key(\$container, $key) {
-    $container.defined
+    defined($container)
         ?? $container.at-key($key)
         !! Any!Any::butWHENCE(sub (\$var) {
-            $container.defined && die("Autovivification collision");
+            defined($container) && die("Autovivification collision");
             $container = Hash.new;
             $container!Hash::extend($key, $var);
         });
 }
 
 my $i = 0;
 my %hash;
-%hash{$i} = $i until ($i++) == 100000;
+%hash{$i} = $i until ($i++) == 1000000;

src/Op.pm

@@ -1190,7 +1190,11 @@ use CgOp;
         my ($self, $body) = @_;
         no strict 'refs';
         my $name = $self->name;
-        &{ "CgOp::bif_$name" }(map { $_->cgop($body) } @{ $self->args });
+        my @a = (map { $_->cgop($body) } @{ $self->args });
+        if ($name eq 'defined') {
+            return CgOp::obj_asdef($a[0]);
+        }
+        &{ "CgOp::bif_$name" }(@a);
     }
 
     __PACKAGE__->meta->make_immutable;

src/Optimizer/Simplifier.pm

@@ -43,6 +43,7 @@ our %funcs = (
     '&postfix:<++>' => \&do_postinc,
     '&postcircumfix:<{ }>' => \&do_atkey,
     '&postcircumfix:<[ ]>' => \&do_atpos,
+    '&defined' => \&do_defined,
 );
 
 sub do_assign {
@@ -77,6 +78,12 @@ sub do_numeq {
     return Op::Builtin->new(name => 'numeq', args => $args);
 }
 
+sub do_defined {
+    my ($body, $nv, $invname, $args) = @_;
+    return unless @$args == 1;
+    return Op::Builtin->new(name => 'defined', args => $args);
+}
+
 # TODO: similar conversion for :delete and :exists
 sub do_atkey {
     my ($body, $nv, $invname, $args) = @_;