remove extra division in mpq/aors.c

[Marc Glisse]

Just to make my earlier remarks more constructive, 2 versions of what I 
was suggesting are attached.

-- 
Marc Glisse
-------------- next part --------------
*** gmp.98add4b37ac1/mpz/divegcd.c	2011-02-27 11:08:28.455139952 +0100
--- /data/repos/gmp/mpz/divegcd.c	2011-02-27 11:08:09.418916311 +0100
***************
*** 103,112 ****
--- 103,120 ----
    if (SIZ(d) == 1)
      {
        mp_limb_t  dl = PTR(d)[0];
        int        twos;
  
+       count_trailing_zeros (twos, dl);
+       if (twos != 0)
+ 	{
+ 	  dl >>= twos;
+ 	  mpz_tdiv_q_2exp (q, a, twos);
+ 	  a=q;
+ 	}
+ 
        if (dl == 1)
  	{
  	  if (q != a)
  	    mpz_set (q, a);
  	  return;
***************
*** 124,157 ****
  	  mpz_divexact_by5 (q, a);
  	  return;
  	}
  #endif
  
!       count_trailing_zeros (twos, dl);
!       dl >>= twos;
!       mpz_tdiv_q_2exp (q, a, twos);
! 
!       if (dl == 1)
! 	{
! 	  return;
! 	}
! #if GMP_NUMB_BITS % 2 == 0
!       if (dl == 3)
! 	{
! 	  mpz_divexact_by3 (q, q);
! 	  return;
! 	}
! #endif
! #if GMP_NUMB_BITS % 4 == 0
!       if (dl == 5)
! 	{
! 	  mpz_divexact_by5 (q, q);
! 	  return;
! 	}
! #endif
! 
!       mpz_divexact_ui (q, q, dl);
        return;
      }
  
    mpz_divexact (q, a, d);
  }
--- 132,142 ----
  	  mpz_divexact_by5 (q, a);
  	  return;
  	}
  #endif
  
!       mpz_divexact_ui (q, a, dl);
        return;
      }
  
    mpz_divexact (q, a, d);
  }
-------------- next part --------------
*** gmp.98add4b37ac1/mpz/divegcd.c	2011-02-27 11:09:30.266945592 +0100
--- /data/repos/gmp/mpz/divegcd.c	2011-02-27 11:09:12.754883638 +0100
***************
*** 42,54 ****
     Future: This could change to an mpn_divexact_gcd, possibly partly
     inlined, if/when the relevant mpq functions change to an mpn based
     implementation.  */
  
  
- #if GMP_NUMB_BITS % 2 == 0
  static void
! mpz_divexact_by3 (mpz_ptr q, mpz_srcptr a)
  {
    mp_size_t  size = SIZ(a);
    if (size == 0)
      {
        SIZ(q) = 0;
--- 42,53 ----
     Future: This could change to an mpn_divexact_gcd, possibly partly
     inlined, if/when the relevant mpq functions change to an mpn based
     implementation.  */
  
  
  static void
! mpz_divexact_by_limb (mpz_ptr q, mpz_srcptr a, mp_limb_t di)
  {
    mp_size_t  size = SIZ(a);
    if (size == 0)
      {
        SIZ(q) = 0;
***************
*** 60,101 ****
        mp_ptr     qp;
  
        MPZ_REALLOC (q, abs_size);
  
        qp = PTR(q);
!       mpn_bdiv_dbm1 (qp, PTR(a), abs_size, GMP_NUMB_MASK / 3);
  
        abs_size -= (qp[abs_size-1] == 0);
        SIZ(q) = (size>0 ? abs_size : -abs_size);
      }
  }
- #endif
- #if GMP_NUMB_BITS % 4 == 0
- static void
- mpz_divexact_by5 (mpz_ptr q, mpz_srcptr a)
- {
-   mp_size_t  size = SIZ(a);
-   if (size == 0)
-     {
-       SIZ(q) = 0;
-       return;
-     }
-   else
-     {
-       mp_size_t  abs_size = ABS(size);
-       mp_ptr     qp;
- 
-       MPZ_REALLOC (q, abs_size);
- 
-       qp = PTR(q);
-       mpn_bdiv_dbm1 (qp, PTR(a), abs_size, GMP_NUMB_MASK / 5);
- 
-       abs_size -= (qp[abs_size-1] == 0);
-       SIZ(q) = (size>0 ? abs_size : -abs_size);
-     }
- }
- #endif
  
  void
  mpz_divexact_gcd (mpz_ptr q, mpz_srcptr a, mpz_srcptr d)
  {
    ASSERT (mpz_sgn (d) > 0);
--- 59,74 ----
        mp_ptr     qp;
  
        MPZ_REALLOC (q, abs_size);
  
        qp = PTR(q);
!       mpn_bdiv_dbm1 (qp, PTR(a), abs_size, di);
  
        abs_size -= (qp[abs_size-1] == 0);
        SIZ(q) = (size>0 ? abs_size : -abs_size);
      }
  }
  
  void
  mpz_divexact_gcd (mpz_ptr q, mpz_srcptr a, mpz_srcptr d)
  {
    ASSERT (mpz_sgn (d) > 0);
***************
*** 103,157 ****
    if (SIZ(d) == 1)
      {
        mp_limb_t  dl = PTR(d)[0];
        int        twos;
  
!       if (dl == 1)
! 	{
! 	  if (q != a)
! 	    mpz_set (q, a);
! 	  return;
! 	}
! #if GMP_NUMB_BITS % 2 == 0
!       if (dl == 3)
! 	{
! 	  mpz_divexact_by3 (q, a);
! 	  return;
! 	}
! #endif
! #if GMP_NUMB_BITS % 4 == 0
!       if (dl == 5)
  	{
! 	  mpz_divexact_by5 (q, a);
! 	  return;
  	}
- #endif
- 
-       count_trailing_zeros (twos, dl);
-       dl >>= twos;
-       mpz_tdiv_q_2exp (q, a, twos);
  
        if (dl == 1)
  	{
  	  return;
  	}
! #if GMP_NUMB_BITS % 2 == 0
!       if (dl == 3)
! 	{
! 	  mpz_divexact_by3 (q, q);
! 	  return;
! 	}
! #endif
! #if GMP_NUMB_BITS % 4 == 0
!       if (dl == 5)
  	{
! 	  mpz_divexact_by5 (q, q);
  	  return;
  	}
- #endif
  
!       mpz_divexact_ui (q, q, dl);
        return;
      }
  
    mpz_divexact (q, a, d);
  }
--- 76,106 ----
    if (SIZ(d) == 1)
      {
        mp_limb_t  dl = PTR(d)[0];
        int        twos;
  
!       count_trailing_zeros (twos, dl);
!       if (twos != 0)
  	{
! 	  dl >>= twos;
! 	  mpz_tdiv_q_2exp (q, a, twos);
! 	  a=q;
  	}
  
        if (dl == 1)
  	{
+ 	  if (q != a)
+ 	    mpz_set (q, a);
  	  return;
  	}
!       if (GMP_NUMB_MASK % dl == 0)
  	{
! 	  mpz_divexact_by_limb (q, a, GMP_NUMB_MASK / dl);
  	  return;
  	}
  
!       mpz_divexact_ui (q, a, dl);
        return;
      }
  
    mpz_divexact (q, a, d);
  }