[RFC][PATCH] mini-gmp: move memory allocation out of loops

[Marco Bodrato]

Ciao!

Il Mar, 6 Febbraio 2018 7:21 pm, Ilya Yanok ha scritto:
> I did a small patch for mini-gmp, that removes memory allocations in loop,
> when mpz_get_str gets called. This might be undesired behaviour in the

May I suggest a different approach?

Modify mpn_div_qr_1_preinv to work in-place, whenever the funcion is
called to overwrite its input anyway.

I mean:

------8<------
diff -r c9ee97d5775c mini-gmp/mini-gmp.c
--- a/mini-gmp/mini-gmp.c	Thu Feb 08 13:11:17 2018 +0100
+++ b/mini-gmp/mini-gmp.c	Fri Feb 09 21:31:11 2018 +0100
@@ -930,7 +930,7 @@

   if (inv->shift > 0)
     {
-      tp = gmp_xalloc_limbs (nn);
+      tp = (qp == np) ? qp : gmp_xalloc_limbs (nn);
       r = mpn_lshift (tp, np, nn, inv->shift);
       np = tp;
     }
@@ -947,7 +947,7 @@
       if (qp)
 	qp[nn] = q;
     }
-  if (inv->shift > 0)
+  if (inv->shift > 0 && (tp != qp))
     gmp_free (tp);

   return r >> inv->shift;
------8<------

Can you check if this gives you the desired result? I did not test it widely.

Ĝis,
m

-- 
http://bodrato.it/papers/