I doubt that a for ("a",@ar,"z") {} is still that performant, because the heuristics might not detect anymore the array in between

LanX, you are right:

cmpthese(0, {
        map => sub {map_die(\@arr)},
        for => sub {for_die(\@arr)},
    });

sub map_die ($ar) {
    eval {map {die} 0, @$ar};
}

sub for_die ($ar) {
    eval {
        for (0, @$ar) {
            die;
        }
    }
}
__DATA__
      Rate for map
for 1390/s  -- -1%
map 1404/s  1%  --
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