* bignum.c: The branch condition of selecting multiplication
  algorighms should check smaller argument because Karatsuba and Toom3
  is effective only if both arguments are big.
  (bary_mul_toom3_branch): Compare the smaller argument to
  TOOM3_MUL_DIGITS.
  (bary_mul): Compare the smaller argument to KARATSUBA_MUL_DIGITS.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42360 b2dd03c8-39d4-4d8f-98ff-823fe69b080e