#!/usr/bin/perl

use Benchmark;

$rein = '+5000*'; 

timethese(10000000, {
   A => sub {
      if ($rein =~ m~(?:-|\+|\*|/)~) {
      	# Do nothing
      }
   },
   B => sub {
      if ($rein =~ m~-~ or m~\+~ or m~\*~ or m~/~) {
      	# Do nothing
      }
   },
   C => sub {
      if ($rein =~ m~[-+*/]~) {
      	# Do nothing
      }
   },
   D => sub {
      if ($rein =~ m~[-]~ or m~[+]~ or m~[*]~ or m~[/]~) {
      	# Do nothing
      }
   },
   E => sub {
      if (index($_, '-') > -1 or index($_, '+') > -1 or index($_, '*') > -1 or index($_, '/') > -1) {
      	# Do nothing
      }
   }
});

Benchmark: timing 1000000 iterations of A, B, C, D, E...
    A:  1 wallclock secs ( 0.80 usr +  0.00 sys =  0.80 CPU) @ 1246882.79/s
    B:  1 wallclock secs ( 1.07 usr +  0.00 sys =  1.07 CPU) @ 932835.820/s
    C:  1 wallclock secs ( 0.64 usr +  0.00 sys =  0.64 CPU) @ 1562500.00/s
    D:  1 wallclock secs ( 0.95 usr + -0.01 sys =  0.94 CPU) @ 1063829.79/s
    E:  2 wallclock secs ( 1.45 usr +  0.00 sys =  1.45 CPU) @ 688705.230/s

Windows 2000SP3
1,4 GHZ
1024 MB RAM