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Speed up logcount on bignums

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* src/data.c (Flogcount): Speed up by using the mpz equivalent
of ~X instead of -X-1.
This commit is contained in:
Paul Eggert 2018-08-16 19:53:21 -07:00
parent 44ad4a15a0
commit bb7e033891
1 changed files with 1 additions and 2 deletions
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src/data.c
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@ -3350,8 +3350,7 @@ representation. */)
return make_fixnum (mpz_popcount (XBIGNUM (value)->value));
mpz_t tem;
mpz_init (tem);
mpz_neg (tem, XBIGNUM (value)->value);
mpz_sub_ui (tem, tem, 1);
mpz_com (tem, XBIGNUM (value)->value);
Lisp_Object result = make_fixnum (mpz_popcount (tem));
mpz_clear (tem);
return result;