$ perl -Mre=debug -e'/[^01]/, /^[01]+$/'
Freeing REx: `","'
Compiling REx `[^01]'
size 12 Got 100 bytes for offset annotations.
first at 1
   1: ANYOF[\0-/2-\377{unicode_all}](12)
  12: END(0)
stclass `ANYOF[\0-/2-\377{unicode_all}]' minlen 1 
Offsets: [12]
        1[5] 0[0] 0[0] 0[0] 0[0] 0[0] 0[0] 0[0] 0[0] 0[0] 0[0] 6[0] 
Compiling REx `^[01]+$'
size 15 Got 124 bytes for offset annotations.
first at 2
synthetic stclass `ANYOF[01]'.
   1: BOL(2)
   2: PLUS(14)
   3:   ANYOF[01](0)
  14: EOL(15)
  15: END(0)
floating `'$ at 1..2147483647 (checking floating) stclass `ANYOF[01]' anchored(BOL) minlen 1 
Offsets: [15]
        1[1] 6[4] 2[4] 0[0] 0[0] 0[0] 0[0] 0[0] 0[0] 0[0] 0[0] 0[0] 0[0] 7[1] 8[0] 
Freeing REx: `"[^01]"'
Freeing REx: `"^[01]+$"'