I was thinking about that! Convert to a string, and look to see if the first char is a "-" to determine sign. I don't think your routine works, though. 
sub re {
  my $i=0; /-(?{$i=$i+1})/ for @_; $i=~/0|2/;
}

[download]
given the same test cases as before,
xyxorNeg()spaceship()mult()anchor()re()
111111
-1101
1-101
-1-11111
And actually, its only twice as slow...
unit squarespaceshipmultiplylogicre
spaceship--------worse 21.74%worse 12.21%better 86.26%
multiplybetter 21.74%--------better 10.86%better 89.25%
logicbetter 12.21%worse 10.86%--------better 87.94%
reg expworse 86.26%worse 89.25%worse 87.94%--------

In reply to Re^2: Seeing if two numbers have the same sign by WoodyWeaver
in thread Seeing if two numbers have the same sign by grinder

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.