Quite right, I'd got caught by an optimization. I ran (adjusting code to your example) 

for my $tab ( 1 .. 3 ) {
    my @array = frobnicate($tab);
    printf "Array ref: %s\n", \@array;
    printf "Annoymous: %s\n", [@array];
}

sub frobnicate {
    return ( 0 .. shift );
}
__END__
Array ref: ARRAY(0x826a924)
Annoymous: ARRAY(0x8183a54)
Array ref: ARRAY(0x826a924)
Annoymous: ARRAY(0x826d818)
Array ref: ARRAY(0x826a924)
Annoymous: ARRAY(0x82115f8)

[download]
The same address even though @array is declared in the loop. The variable is being reused. Assigning \@array to something prevents the optimization. 
my %data;

for my $tab ( 1 .. 3 ) {
    my @array = frobnicate($tab);
    printf "Array ref: %s\n", \@array;
    printf "Annoymous: %s\n", [@array];
    $data{$tab} = \@array;
}

sub frobnicate {
    return ( 0 .. shift );
}
__END__
Array ref: ARRAY(0x826a924)
Annoymous: ARRAY(0x8183a54)
Array ref: ARRAY(0x819f318)
Annoymous: ARRAY(0x8183798)
Array ref: ARRAY(0x826ade8)
Annoymous: ARRAY(0x819f304)

[download]
Something to bear in mind when benchmarking.

In reply to Re^3: references--hard vs anonymous operational weirdness by hipowls
in thread references--hard vs anonymous operational weirdness by hill

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.