mul.c, mul.dat: if both arguments are the same, call sqr

   prevents infinite loops already fixed in sqr and as yet unknown
   bugs and assures the same behaviour as sqr in corner cases (overflow etc.)


git-svn-id: svn://scm.gforge.inria.fr/svn/mpc/trunk@833 211d60ee-9f03-0410-a15a-8952a2c7a4e4

1 files changed, 6 insertions, 0 deletions

diff --git a/src/mul.c b/src/mul.c
index 5cd5bb8..0de9328 100644
--- a/src/mul.c
+++ b/src/mul.c
@@ -109,6 +109,12 @@ mpc_mul (mpc_ptr a, mpc_srcptr b, mpc_srcptr c, mpc_rnd_t rnd)
     /* note that a cannot be a zero */
     return mul_pure_imaginary (a, b, MPC_IM (c), rnd, (a == b || a == c));
 
+  /* Check if b==c and call mpc_sqr in this case, to make sure            */
+  /* mpc_mul(a,b,b) behaves exactly like mpc_sqr(a,b) concerning          */
+  /* internal overflows etc.                                              */
+  if (mpc_cmp (b, c) == 0)
+     return mpc_sqr (a, b, rnd);
+
   /* If the real and imaginary part of one argument have a very different */
   /* exponent, it is not reasonable to use Karatsuba multiplication.      */
   if (   SAFE_ABS (mpfr_exp_t,