juddhuck,
I don't know much about the optree, but perl -MO=Concise may be of help in comparing the versions that leak against the ones that don't. Incidently, the following doesn't but is functionally equivalent:

#!/usr/bin/perl
use strict;
use warnings;

my $i = 0;
bar();
sub bar {
    goto &bar if foo();
    return;
}
sub foo {return $i++ < 1_000_000_000;}
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