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<?php $r1 = '/(?!<\\\\)\\\\n/'; $r2 = '((?:\\\\(*SKIP)(*FAIL))\\\\n)'; var_dump(preg_match($r1, "\\\\\\\\\n"));
Finding entry points
Branch analysis from position: 0
1 jumps found. (Code = 62) Position 1 = -2
filename:       /in/E2qCr
function name:  (null)
number of ops:  10
compiled vars:  !0 = $r1, !1 = $r2
line      #* E I O op                           fetch          ext  return  operands
-------------------------------------------------------------------------------------
    3     0  E >   ASSIGN                                                   !0, '%2F%28%3F%21%3C%5C%5C%29%5C%5Cn%2F'
    4     1        ASSIGN                                                   !1, '%28%28%3F%3A%5C%5C%28%2ASKIP%29%28%2AFAIL%29%29%5C%5Cn%29'
    6     2        INIT_FCALL                                               'var_dump'
          3        INIT_FCALL                                               'preg_match'
          4        SEND_VAR                                                 !0
          5        SEND_VAL                                                 '%5C%5C%5C%5C%0A'
          6        DO_ICALL                                         $4      
          7        SEND_VAR                                                 $4
          8        DO_ICALL                                                 
          9      > RETURN                                                   1

Generated using Vulcan Logic Dumper, using php 8.0.0


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