use Benchmark qw {:all};
use 5.016;

my %hash;

#  set up the hash
for (1001..2000) {
    $hash{$_}++;
}
#  two keys we use below
our $key1 = 1001;
our $key2 = 1002;
#  hash key 1 is SV
$hash{$key1} = 1;
#  hash key 2 is RV
$hash{$key2} = {1..10};

#  assign to global as a baseline
our $xx_global;

#  keys are short for formatting reasons 
#  (and kept the same as in the original post)
#  char1:     e = exists check, v = value check
#  chars 2,3: ck = constant key, vk = variable key
#  chars 4,5: sv = key contains scalar value, rv = key contains reference
#  char 6:    l = assign to lexical, g = assign to global
#  thus
#  ecksvl means "exists check using constant key, scalar value, assigned to lexical"

my %checks = (
    evksvg => '$xx_global = exists $hash{$key1} ? 1 : 2',
    vvksvg => '$xx_global = $hash{$key1} ? 1 : 2',
    evkrvg => '$xx_global = exists $hash{$key2} ? 1 : 2',
    vvkrvg => '$xx_global = $hash{$key2} ? 1 : 2',
);


cmpthese (
    -2,
    \%checks
);