Well it's a question of weird optimization, a constant scalar is passed in a certain snippet of code, so no need to switch the reference at runtime.

This works with explicit refs like [1,2] and {1,2} but not with constants, they needlessly get at runtime a new reference, each time the loop gets there... just compare: check(qw/ Scalarref \1 /);

OUTPUT

--- Scalarref 
    for (1..3) {
    pr \1;
        print "\n\t"; #UPDATE
    for (1..3) {
        pr \1;
    }
    print "\n";
    }
REF(0x8190768)    
    REF(0x8190744)    REF(0x8190750)    REF(0x8190744)    
REF(0x8190750)    
    REF(0x8195394)    REF(0x8190744)    REF(0x8195394)    
REF(0x8190744)    
    REF(0x8190768)    REF(0x8195394)    REF(0x8190768)
[download]

each time a new ref instead of one ref