How about ...

use Data::Dumper;

my @data = (
qq{key1~key2~key3
Value for key1, key2, key3},

qq{key4~key5~key6
Value for key4, key5, key6},

qq{key7~key8~key9
Value for key7, key8, key9}
);

my %hash;
for(@data) {
    my($value, @keys) = reverse /(\w+)(?:~|$)/g, /\n(.*)/;
    @hash{@keys} = ($value) x @keys;
}

print Dumper( \%hash );

__output__

$VAR1 = {
          'key7' => 'Value for key7, key8, key9',
          'key8' => 'Value for key7, key8, key9',
          'key9' => 'Value for key7, key8, key9',
          'key1' => 'Value for key1, key2, key3',
          'key2' => 'Value for key1, key2, key3',
          'key3' => 'Value for key1, key2, key3',
          'key4' => 'Value for key4, key5, key6',
          'key5' => 'Value for key4, key5, key6',
          'key6' => 'Value for key4, key5, key6'
        };
[download]

And not a map() in sight!
HTH

_________
broquaint