$ perl -le '("\n"x64_000)=~/\A(?:${\q[^$\n]}){1,32766}/m;print length $&'
32766

Compiling REx `\A(?:^$\n){1,32766}'
size 10 first at 2
   1: SBOL(2)
   2: CURLYM[0] {1,32766}(10)
   4:   MBOL(5)
   5:   MEOL(6)
   6:   EXACT <
>(8)
   8:   SUCCEED(0)
   9:   NOTHING(10)
  10: END(0)
anchored `
' at 0 (checking anchored noscan) anchored(SBOL) minlen 1

$ perl -le '("\n"x64_000)=~/\A(?:${\q[^$\n]})+/m;print length $&'
64000

Compiling REx `\A(?:^$\n)+'
size 10 first at 2
   1: SBOL(2)
   2: CURLYM[0] {1,32767}(10)
REG_INFTY----------^
   4:   MBOL(5)
   5:   MEOL(6)
   6:   EXACT <
>(8)
   8:   SUCCEED(0)
   9:   NOTHING(10)
  10: END(0)
anchored `
' at 0 (checking anchored noscan) anchored(SBOL) minlen 1