mpz: Lazy allocation.

39 files changed, 96 insertions, 85 deletions

diff --git a/mpz/2fac_ui.c b/mpz/2fac_ui.c
index 37e6c468b..c6e2a90ff 100644
--- a/mpz/2fac_ui.c
+++ b/mpz/2fac_ui.c
@@ -67,8 +67,8 @@ mpz_2fac_ui (mpz_ptr x, unsigned long n)
     mpz_mul_2exp (x, x, count);
   } else { /* n is odd */
     if (n <= ODD_DOUBLEFACTORIAL_TABLE_LIMIT) {
-	PTR (x)[0] = __gmp_odd2fac_table[n >> 1];
-	SIZ (x) = 1;
+      MPZ_NEWALLOC (x, 1)[0] = __gmp_odd2fac_table[n >> 1];
+      SIZ (x) = 1;
     } else if (BELOW_THRESHOLD (n, FAC_2DSC_THRESHOLD)) { /* odd basecase, */
       mp_limb_t *factors, prod, max_prod, j;
       TMP_SDECL;
diff --git a/mpz/aors_ui.h b/mpz/aors_ui.h
index 2e3c481ab..eaf02c8e9 100644
--- a/mpz/aors_ui.h
+++ b/mpz/aors_ui.h
@@ -80,7 +80,7 @@ FUNCTION (mpz_ptr w, mpz_srcptr u, unsigned long int vval)
   usize = SIZ (u);
   if (usize == 0)
     {
-      PTR (w)[0] = vval;
+      MPZ_NEWALLOC (w, 1)[0] = vval;
       SIZ (w) = VARIATION_NEG (vval != 0);
       return;
     }
diff --git a/mpz/bin_ui.c b/mpz/bin_ui.c
index c24b21724..bc5894510 100644
--- a/mpz/bin_ui.c
+++ b/mpz/bin_ui.c
@@ -83,7 +83,7 @@ mpz_bin_ui (mpz_ptr r, mpz_srcptr n, unsigned long int k)
 
   /* Now wanting bin(ni+k,k), with ni positive, and "negate" is the sign (0
      for positive, 1 for negative). */
-  SIZ (r) = 1; PTR (r)[0] = 1;
+  SIZ (r) = 1; MPZ_NEWALLOC (r, 1)[0] = 1;
 
   /* Rewrite bin(n,k) as bin(n,n-k) if that is smaller.  In this case it's
      whether ni+k-k < k meaning ni<k, and if so change to denominator ni+k-k
diff --git a/mpz/bin_uiui.c b/mpz/bin_uiui.c
index 94a9dc5c7..9d661d54e 100644
--- a/mpz/bin_uiui.c
+++ b/mpz/bin_uiui.c
@@ -642,7 +642,7 @@ mpz_goetgheluck_bin_uiui (mpz_ptr r, unsigned long int n, unsigned long int k)
     }
   else
     {
-      PTR (r)[0] = prod;
+      MPZ_NEWALLOC (r, 1)[0] = prod;
       SIZ (r) = 1;
     }
   TMP_FREE;
@@ -677,10 +677,10 @@ mpz_bin_uiui (mpz_ptr r, unsigned long int n, unsigned long int k)
     /* Rewrite bin(n,k) as bin(n,n-k) if that is smaller. */
     k = MIN (k, n - k);
     if (k < 2) {
-      PTR(r)[0] = k ? n : 1; /* 1 + ((-k) & (n-1)); */
+      MPZ_NEWALLOC (r, 1)[0] = k ? n : 1; /* 1 + ((-k) & (n-1)); */
       SIZ(r) = 1;
     } else if (n <= ODD_FACTORIAL_EXTTABLE_LIMIT) { /* k >= 2, n >= 4 */
-      PTR(r)[0] = bc_bin_uiui (n, k);
+      MPZ_NEWALLOC (r, 1)[0] = bc_bin_uiui (n, k);
       SIZ(r) = 1;
     } else if (k <= ODD_FACTORIAL_TABLE_LIMIT)
       mpz_smallk_bin_uiui (r, n, k);
diff --git a/mpz/cdiv_qr_ui.c b/mpz/cdiv_qr_ui.c
index 1ccfbbe7f..f82841a7a 100644
--- a/mpz/cdiv_qr_ui.c
+++ b/mpz/cdiv_qr_ui.c
@@ -108,7 +108,7 @@ mpz_cdiv_qr_ui (mpz_ptr quot, mpz_ptr rem, mpz_srcptr dividend, unsigned long in
 	      rl = divisor - rl;
 	    }
 
-	  PTR(rem)[0] = rl;
+	  MPZ_NEWALLOC (rem, 1)[0] = rl;
 	  SIZ(rem) = -(rl != 0);
 	}
       qn = nn - (qp[nn - 1] == 0);
diff --git a/mpz/cdiv_r_ui.c b/mpz/cdiv_r_ui.c
index 68fb149c4..bd1c82293 100644
--- a/mpz/cdiv_r_ui.c
+++ b/mpz/cdiv_r_ui.c
@@ -101,7 +101,7 @@ mpz_cdiv_r_ui (mpz_ptr rem, mpz_srcptr dividend, unsigned long int divisor)
 	  if (ns >= 0)
 	    rl = divisor - rl;
 
-	  PTR(rem)[0] = rl;
+	  MPZ_NEWALLOC (rem, 1)[0] = rl;
 	  SIZ(rem) = -1;
 	}
     }
diff --git a/mpz/cfdiv_q_2exp.c b/mpz/cfdiv_q_2exp.c
index 366d6aa70..f0c36dd15 100644
--- a/mpz/cfdiv_q_2exp.c
+++ b/mpz/cfdiv_q_2exp.c
@@ -53,7 +53,7 @@ cfdiv_q_2exp (mpz_ptr w, mpz_srcptr u, mp_bitcnt_t cnt, int dir)
   if (wsize <= 0)
     {
       /* u < 2**cnt, so result 1, 0 or -1 according to rounding */
-      PTR(w)[0] = 1;
+      MPZ_NEWALLOC (w, 1)[0] = 1;
       SIZ(w) = (usize == 0 || (usize ^ dir) < 0 ? 0 : dir);
       return;
     }
diff --git a/mpz/clear.c b/mpz/clear.c
index d1541e91c..3be7deffa 100644
--- a/mpz/clear.c
+++ b/mpz/clear.c
@@ -36,5 +36,6 @@ see https://www.gnu.org/licenses/.  */
 void
 mpz_clear (mpz_ptr x)
 {
-  __GMP_FREE_FUNC_LIMBS (PTR (x), ALLOC(x));
+  if (ALLOC (x))
+    __GMP_FREE_FUNC_LIMBS (PTR (x), ALLOC(x));
 }
diff --git a/mpz/clears.c b/mpz/clears.c
index dac988738..ac00b9931 100644
--- a/mpz/clears.c
+++ b/mpz/clears.c
@@ -41,7 +41,8 @@ mpz_clears (mpz_ptr x, ...)
 
   while (x != NULL)
     {
-      __GMP_FREE_FUNC_LIMBS (PTR (x), ALLOC(x));
+      if (ALLOC (x))
+	__GMP_FREE_FUNC_LIMBS (PTR (x), ALLOC (x));
       x = va_arg (ap, mpz_ptr);
     }
 
diff --git a/mpz/com.c b/mpz/com.c
index 66d69ce8b..c2803b4b3 100644
--- a/mpz/com.c
+++ b/mpz/com.c
@@ -49,7 +49,7 @@ mpz_com (mpz_ptr dst, mpz_srcptr src)
       if (UNLIKELY (size == 0))
 	{
 	  /* special case, as mpn_add_1 wants size!=0 */
-	  PTR (dst)[0] = 1;
+	  MPZ_NEWALLOC (dst, 1)[0] = 1;
 	  SIZ (dst) = -1;
 	}
       else
diff --git a/mpz/fac_ui.c b/mpz/fac_ui.c
index e0932272f..18993d9f4 100644
--- a/mpz/fac_ui.c
+++ b/mpz/fac_ui.c
@@ -60,7 +60,7 @@ mpz_fac_ui (mpz_ptr x, unsigned long n)
 
   if (n < numberof (table))
     {
-      PTR (x)[0] = table[n];
+      MPZ_NEWALLOC (x, 1)[0] = table[n];
       SIZ (x) = 1;
     }
   else if (BELOW_THRESHOLD (n, FAC_ODD_THRESHOLD))
diff --git a/mpz/fdiv_qr_ui.c b/mpz/fdiv_qr_ui.c
index c8435a423..074952837 100644
--- a/mpz/fdiv_qr_ui.c
+++ b/mpz/fdiv_qr_ui.c
@@ -107,7 +107,7 @@ mpz_fdiv_qr_ui (mpz_ptr quot, mpz_ptr rem, mpz_srcptr dividend, unsigned long in
 	      rl = divisor - rl;
 	    }
 
-	  PTR(rem)[0] = rl;
+	  MPZ_NEWALLOC (rem, 1)[0] = rl;
 	  SIZ(rem) = rl != 0;
 	}
       qn = nn - (qp[nn - 1] == 0);
diff --git a/mpz/fdiv_r_ui.c b/mpz/fdiv_r_ui.c
index 98dd56c6f..f256da05f 100644
--- a/mpz/fdiv_r_ui.c
+++ b/mpz/fdiv_r_ui.c
@@ -99,7 +99,7 @@ mpz_fdiv_r_ui (mpz_ptr rem, mpz_srcptr dividend, unsigned long int divisor)
 	  if (ns < 0)
 	    rl = divisor - rl;
 
-	  PTR(rem)[0] = rl;
+	  MPZ_NEWALLOC (rem, 1)[0] = rl;
 	  SIZ(rem) = 1;
 	}
     }
diff --git a/mpz/fib2_ui.c b/mpz/fib2_ui.c
index ddf456f58..1a64d66f1 100644
--- a/mpz/fib2_ui.c
+++ b/mpz/fib2_ui.c
@@ -41,9 +41,9 @@ mpz_fib2_ui (mpz_ptr fn, mpz_ptr fnsub1, unsigned long n)
 
   if (n <= FIB_TABLE_LIMIT)
     {
-      PTR(fn)[0] = FIB_TABLE (n);
+      MPZ_NEWALLOC (fn, 1)[0] = FIB_TABLE (n);
       SIZ(fn) = (n != 0);      /* F[0]==0, others are !=0 */
-      PTR(fnsub1)[0] = FIB_TABLE ((int) n - 1);
+      MPZ_NEWALLOC (fnsub1, 1)[0] = FIB_TABLE ((int) n - 1);
       SIZ(fnsub1) = (n != 1);  /* F[1-1]==0, others are !=0 */
       return;
     }
diff --git a/mpz/fib_ui.c b/mpz/fib_ui.c
index f591c0850..9976e0067 100644
--- a/mpz/fib_ui.c
+++ b/mpz/fib_ui.c
@@ -65,7 +65,7 @@ mpz_fib_ui (mpz_ptr fn, unsigned long n)
 
   if (n <= FIB_TABLE_LIMIT)
     {
-      PTR(fn)[0] = FIB_TABLE (n);
+      MPZ_NEWALLOC (fn, 1)[0] = FIB_TABLE (n);
       SIZ(fn) = (n != 0);      /* F[0]==0, others are !=0 */
       return;
     }
diff --git a/mpz/gcd.c b/mpz/gcd.c
index 87c6a8f17..b7a804e2a 100644
--- a/mpz/gcd.c
+++ b/mpz/gcd.c
@@ -76,14 +76,14 @@ mpz_gcd (mpz_ptr g, mpz_srcptr u, mpz_srcptr v)
   if (usize == 1)
     {
       SIZ (g) = 1;
-      PTR (g)[0] = mpn_gcd_1 (vp, vsize, up[0]);
+      MPZ_NEWALLOC (g, 1)[0] = mpn_gcd_1 (vp, vsize, up[0]);
       return;
     }
 
   if (vsize == 1)
     {
       SIZ(g) = 1;
-      PTR (g)[0] = mpn_gcd_1 (up, usize, vp[0]);
+      MPZ_NEWALLOC (g, 1)[0] = mpn_gcd_1 (up, usize, vp[0]);
       return;
     }
 
diff --git a/mpz/gcd_ui.c b/mpz/gcd_ui.c
index e26d03f64..8a3329b4b 100644
--- a/mpz/gcd_ui.c
+++ b/mpz/gcd_ui.c
@@ -78,7 +78,7 @@ mpz_gcd_ui (mpz_ptr w, mpz_srcptr u, unsigned long int v)
 
   if (w != NULL)
     {
-      PTR(w)[0] = res;
+      MPZ_NEWALLOC (w, 1)[0] = res;
       SIZ(w) = res != 0;
     }
   return res;
diff --git a/mpz/gcdext.c b/mpz/gcdext.c
index 01b1f8379..4863d3bab 100644
--- a/mpz/gcdext.c
+++ b/mpz/gcdext.c
@@ -72,7 +72,7 @@ mpz_gcdext (mpz_ptr g, mpz_ptr s, mpz_ptr t, mpz_srcptr a, mpz_srcptr b)
       if (s != NULL)
 	{
 	  SIZ (s) = ssize;
-	  PTR (s)[0] = 1;
+	  MPZ_NEWALLOC (s, 1)[0] = 1;
 	}
       return;
     }
diff --git a/mpz/init.c b/mpz/init.c
index 61ef9f87e..d8ba45aeb 100644
--- a/mpz/init.c
+++ b/mpz/init.c
@@ -34,7 +34,8 @@ see https://www.gnu.org/licenses/.  */
 void
 mpz_init (mpz_ptr x)
 {
-  ALLOC (x) = 1;
-  PTR (x) = __GMP_ALLOCATE_FUNC_LIMBS (1);
+  static const mp_limb_t dummy_limb=0xc1a0;
+  ALLOC (x) = 0;
+  PTR (x) = &dummy_limb;
   SIZ (x) = 0;
 }
diff --git a/mpz/inits.c b/mpz/inits.c
index 12a1dc3a0..a9af358de 100644
--- a/mpz/inits.c
+++ b/mpz/inits.c
@@ -35,14 +35,15 @@ see https://www.gnu.org/licenses/.  */
 void
 mpz_inits (mpz_ptr x, ...)
 {
+  static const mp_limb_t dummy_limb=0xc1a0;
   va_list  ap;
 
   va_start (ap, x);
 
   while (x != NULL)
     {
-      ALLOC (x) = 1;
-      PTR (x) = __GMP_ALLOCATE_FUNC_LIMBS (1);
+      ALLOC (x) = 0;
+      PTR (x) = &dummy_limb;
       SIZ (x) = 0;
 
       x = va_arg (ap, mpz_ptr);
diff --git a/mpz/ior.c b/mpz/ior.c
index 76531e2e1..065e29929 100644
--- a/mpz/ior.c
+++ b/mpz/ior.c
@@ -126,10 +126,10 @@ mpz_ior (mpz_ptr res, mpz_srcptr op1, mpz_srcptr op2)
 	      break;
 	  res_size = i + 1;
 
+	  res_ptr = MPZ_NEWALLOC (res, res_size + 1);
+
 	  if (res_size != 0)
 	    {
-	      res_ptr = MPZ_NEWALLOC (res, res_size + 1);
-
 	      /* Second loop computes the real result.  */
 	      mpn_and_n (res_ptr, op1_ptr, op2_ptr, res_size);
 
diff --git a/mpz/iset_d.c b/mpz/iset_d.c
index 2c5b23ab9..43d7d8bbb 100644
--- a/mpz/iset_d.c
+++ b/mpz/iset_d.c
@@ -35,8 +35,7 @@ see https://www.gnu.org/licenses/.  */
 void
 mpz_init_set_d (mpz_ptr dest, double val)
 {
-  ALLOC (dest) = 1;
-  PTR (dest) = __GMP_ALLOCATE_FUNC_LIMBS (1);
+  ALLOC (dest) = 0;
   SIZ (dest) = 0;
   mpz_set_d (dest, val);
 }
diff --git a/mpz/lucnum2_ui.c b/mpz/lucnum2_ui.c
index f8e4fb356..06c93b407 100644
--- a/mpz/lucnum2_ui.c
+++ b/mpz/lucnum2_ui.c
@@ -50,11 +50,11 @@ mpz_lucnum2_ui (mpz_ptr ln, mpz_ptr lnsub1, unsigned long n)
       mp_limb_t  f1 = FIB_TABLE ((int) n - 1);
 
       /* L[n] = F[n] + 2F[n-1] */
-      PTR(ln)[0] = f + 2*f1;
+      MPZ_NEWALLOC (ln, 1)[0] = f + 2*f1;
       SIZ(ln) = 1;
 
       /* L[n-1] = 2F[n] - F[n-1], but allow for L[-1]=-1 */
-      PTR(lnsub1)[0] = (n == 0 ? 1 : 2*f - f1);
+      MPZ_NEWALLOC (lnsub1, 1)[0] = (n == 0 ? 1 : 2*f - f1);
       SIZ(lnsub1) = (n == 0 ? -1 : 1);
 
       return;
diff --git a/mpz/lucnum_ui.c b/mpz/lucnum_ui.c
index d1fe6b54c..1b274fd79 100644
--- a/mpz/lucnum_ui.c
+++ b/mpz/lucnum_ui.c
@@ -68,7 +68,7 @@ mpz_lucnum_ui (mpz_ptr ln, unsigned long n)
   if (n <= FIB_TABLE_LUCNUM_LIMIT)
     {
       /* L[n] = F[n] + 2F[n-1] */
-      PTR(ln)[0] = FIB_TABLE(n) + 2 * FIB_TABLE ((int) n - 1);
+      MPZ_NEWALLOC (ln, 1)[0] = FIB_TABLE(n) + 2 * FIB_TABLE ((int) n - 1);
       SIZ(ln) = 1;
       return;
     }
diff --git a/mpz/mfac_uiui.c b/mpz/mfac_uiui.c
index 3ea36bce9..a34727502 100644
--- a/mpz/mfac_uiui.c
+++ b/mpz/mfac_uiui.c
@@ -59,7 +59,7 @@ mpz_mfac_uiui (mpz_ptr x, unsigned long n, unsigned long m)
   ASSERT (m != 0);
 
   if ((n < 3) | (n - 3 < m - 1)) { /* (n < 3 || n - 1 <= m || m == 0) */
-    PTR (x)[0] = n + (n == 0);
+    MPZ_NEWALLOC (x, 1)[0] = n + (n == 0);
     SIZ (x) = 1;
   } else { /* m < n - 1 < GMP_NUMB_MAX */
     mp_limb_t g, sn;
diff --git a/mpz/mul.c b/mpz/mul.c
index c4389158e..c208a99cd 100644
--- a/mpz/mul.c
+++ b/mpz/mul.c
@@ -104,13 +104,14 @@ mpz_mul (mpz_ptr w, mpz_srcptr u, mpz_srcptr v)
   wsize = usize + vsize;
   if (ALLOC (w) < wsize)
     {
-      if (wp == up || wp == vp)
-	{
-	  free_me = wp;
-	  free_me_size = ALLOC (w);
-	}
-      else
-	(*__gmp_free_func) (wp, (size_t) ALLOC (w) * GMP_LIMB_BYTES);
+      if (ALLOC (w) != 0)
+	if (wp == up || wp == vp)
+	  {
+	    free_me = wp;
+	    free_me_size = ALLOC (w);
+	  }
+	else
+	  (*__gmp_free_func) (wp, (size_t) ALLOC (w) * GMP_LIMB_BYTES);
 
       ALLOC (w) = wsize;
       wp = __GMP_ALLOCATE_FUNC_LIMBS (wsize);
diff --git a/mpz/n_pow_ui.c b/mpz/n_pow_ui.c
index 6c3febe23..c380b981d 100644
--- a/mpz/n_pow_ui.c
+++ b/mpz/n_pow_ui.c
@@ -183,7 +183,7 @@ mpz_n_pow_ui (mpz_ptr r, mp_srcptr bp, mp_size_t bsize, unsigned long int e)
   /* b^0 == 1, including 0^0 == 1 */
   if (e == 0)
     {
-      PTR(r)[0] = 1;
+      MPZ_NEWALLOC (r, 1)[0] = 1;
       SIZ(r) = 1;
       return;
     }
diff --git a/mpz/oddfac_1.c b/mpz/oddfac_1.c
index cf0bff065..cf3178f98 100644
--- a/mpz/oddfac_1.c
+++ b/mpz/oddfac_1.c
@@ -245,6 +245,7 @@ mpz_2multiswing_1 (mpz_ptr x, mp_limb_t n, mp_ptr sieve, mp_ptr factors)
     }
   else
     {
+      ASSERT (ALLOC (x) > 0);
       PTR (x)[0] = prod;
       SIZ (x) = 1;
     }
@@ -290,7 +291,7 @@ mpz_oddfac_1 (mpz_ptr x, mp_limb_t n, unsigned flag)
 
   if (n <= ODD_FACTORIAL_TABLE_LIMIT)
     {
-      PTR (x)[0] = __gmp_oddfac_table[n];
+      MPZ_NEWALLOC (x, 1)[0] = __gmp_oddfac_table[n];
       SIZ (x) = 1;
     }
   else if (n <= ODD_DOUBLEFACTORIAL_TABLE_LIMIT + 1)
diff --git a/mpz/powm.c b/mpz/powm.c
index 4d13da739..0ad2b7203 100644
--- a/mpz/powm.c
+++ b/mpz/powm.c
@@ -86,7 +86,7 @@ mpz_powm (mpz_ptr r, mpz_srcptr b, mpz_srcptr e, mpz_srcptr m)
 	  /* b^0 mod m,  b is anything and m is non-zero.
 	     Result is 1 mod m, i.e., 1 or 0 depending on if m = 1.  */
 	  SIZ(r) = n != 1 || mp[0] != 1;
-	  PTR(r)[0] = 1;
+	  MPZ_NEWALLOC (r, 1)[0] = 1;
 	  TMP_FREE;	/* we haven't really allocated anything here */
 	  return;
 	}
diff --git a/mpz/powm_sec.c b/mpz/powm_sec.c
index 98644ca49..c693023ab 100644
--- a/mpz/powm_sec.c
+++ b/mpz/powm_sec.c
@@ -60,7 +60,7 @@ mpz_powm_sec (mpz_ptr r, mpz_srcptr b, mpz_srcptr e, mpz_srcptr m)
 	  /* b^0 mod m,  b is anything and m is non-zero.
 	     Result is 1 mod m, i.e., 1 or 0 depending on if m = 1.  */
 	  SIZ(r) = n != 1 || mp[0] != 1;
-	  PTR(r)[0] = 1;
+	  MPZ_NEWALLOC (r, 1)[0] = 1;
 	  return;
 	}
       DIVIDE_BY_ZERO;
diff --git a/mpz/powm_ui.c b/mpz/powm_ui.c
index e04bb0ad7..046895cbe 100644
--- a/mpz/powm_ui.c
+++ b/mpz/powm_ui.c
@@ -140,8 +140,8 @@ mpz_powm_ui (mpz_ptr r, mpz_srcptr b, unsigned long int el, mpz_srcptr m)
 	{
 	  /* Exponent is zero, result is 1 mod M, i.e., 1 or 0 depending on if
 	     M equals 1.  */
-	  SIZ(r) = (mn == 1 && mp[0] == 1) ? 0 : 1;
-	  PTR(r)[0] = 1;
+	  SIZ(r) = mn != 1 || mp[0] != 1;
+	  MPZ_NEWALLOC (r, 1)[0] = 1;
 	  return;
 	}
 
diff --git a/mpz/primorial_ui.c b/mpz/primorial_ui.c
index 7a964a1f1..21af098bc 100644
--- a/mpz/primorial_ui.c
+++ b/mpz/primorial_ui.c
@@ -114,7 +114,7 @@ mpz_primorial_ui (mpz_ptr x, unsigned long n)
 
   if (n < numberof (table))
     {
-      PTR (x)[0] = table[n];
+      MPZ_NEWALLOC (x, 1)[0] = table[n];
       SIZ (x) = 1;
     }
   else
@@ -155,7 +155,7 @@ mpz_primorial_ui (mpz_ptr x, unsigned long n)
 	}
       else
 	{
-	  PTR (x)[0] = prod;
+	  MPZ_NEWALLOC (x, 1)[0] = prod;
 	  SIZ (x) = 1;
 	}
 
diff --git a/mpz/realloc.c b/mpz/realloc.c
index 3d2755ca0..050936915 100644
--- a/mpz/realloc.c
+++ b/mpz/realloc.c
@@ -58,14 +58,21 @@ _mpz_realloc (mpz_ptr m, mp_size_t new_alloc)
 	}
     }
 
-  mp = __GMP_REALLOCATE_FUNC_LIMBS (PTR(m), ALLOC(m), new_alloc);
-  PTR(m) = mp;
-  ALLOC(m) = new_alloc;
+  if (ALLOC (m) == 0)
+    {
+      mp = __GMP_ALLOCATE_FUNC_LIMBS (new_alloc);
+    }
+  else
+    {
+      mp = __GMP_REALLOCATE_FUNC_LIMBS (PTR (m), ALLOC (m), new_alloc);
 
-  /* Don't create an invalid number; if the current value doesn't fit after
-     reallocation, clear it to 0.  */
-  if (ABSIZ(m) > new_alloc)
-    SIZ(m) = 0;
+      /* Don't create an invalid number; if the current value doesn't fit after
+	 reallocation, clear it to 0.  */
+      if (UNLIKELY (ABSIZ (m) > new_alloc))
+	SIZ (m) = 0;
+    }
 
+  PTR (m) = mp;
+  ALLOC(m) = new_alloc;
   return (void *) mp;
 }
diff --git a/mpz/realloc2.c b/mpz/realloc2.c
index 3ccfaab1f..ac07e59c8 100644
--- a/mpz/realloc2.c
+++ b/mpz/realloc2.c
@@ -50,11 +50,19 @@ mpz_realloc2 (mpz_ptr m, mp_bitcnt_t bits)
 	}
     }
 
-  PTR(m) = __GMP_REALLOCATE_FUNC_LIMBS (PTR(m), ALLOC(m), new_alloc);
-  ALLOC(m) = new_alloc;
+  if (ALLOC (m) == 0)
+    {
+      PTR (m) = __GMP_ALLOCATE_FUNC_LIMBS (new_alloc);
+    }
+  else
+    {
+      PTR (m) = __GMP_REALLOCATE_FUNC_LIMBS (PTR(m), ALLOC(m), new_alloc);
 
-  /* Don't create an invalid number; if the current value doesn't fit after
-     reallocation, clear it to 0.  */
-  if (ABSIZ(m) > new_alloc)
-    SIZ(m) = 0;
+      /* Don't create an invalid number; if the current value doesn't fit after
+	 reallocation, clear it to 0.  */
+      if (ABSIZ(m) > new_alloc)
+	SIZ(m) = 0;
+    }
+
+  ALLOC(m) = new_alloc;
 }
diff --git a/mpz/set_si.c b/mpz/set_si.c
index 137036833..1d8b8a99c 100644
--- a/mpz/set_si.c
+++ b/mpz/set_si.c
@@ -39,7 +39,7 @@ mpz_set_si (mpz_ptr dest, signed long int val)
 
   vl = (mp_limb_t) ABS_CAST (unsigned long int, val);
 
-  PTR (dest)[0] = vl & GMP_NUMB_MASK;
+  MPZ_NEWALLOC (dest, 1)[0] = vl & GMP_NUMB_MASK;
   size = vl != 0;
 
 #if GMP_NAIL_BITS != 0
diff --git a/mpz/set_ui.c b/mpz/set_ui.c
index f36754cd5..5b4ef58c5 100644
--- a/mpz/set_ui.c
+++ b/mpz/set_ui.c
@@ -37,7 +37,7 @@ mpz_set_ui (mpz_ptr dest, unsigned long int val)
 {
   mp_size_t size;
 
-  PTR (dest)[0] = val & GMP_NUMB_MASK;
+  MPZ_NEWALLOC (dest, 1)[0] = val & GMP_NUMB_MASK;
   size = val != 0;
 
 #if BITS_PER_ULONG > GMP_NUMB_BITS  /* avoid warnings about shift amount */
diff --git a/mpz/tdiv_qr_ui.c b/mpz/tdiv_qr_ui.c
index 4f667abe0..1385fc9a8 100644
--- a/mpz/tdiv_qr_ui.c
+++ b/mpz/tdiv_qr_ui.c
@@ -68,7 +68,7 @@ mpz_tdiv_qr_ui (mpz_ptr quot, mpz_ptr rem, mpz_srcptr dividend, unsigned long in
 	  SIZ(quot) = 0;
 	  rl = np[0];
 	  SIZ(rem) = ns >= 0 ? 1 : -1;
-	  PTR(rem)[0] = rl;
+	  MPZ_NEWALLOC (rem, 1)[0] = rl;
 	  return rl;
 	}
 
@@ -90,10 +90,8 @@ mpz_tdiv_qr_ui (mpz_ptr quot, mpz_ptr rem, mpz_srcptr dividend, unsigned long in
 	SIZ(rem) = 0;
       else
 	{
-	  /* Store the single-limb remainder.  We don't check if there's space
-	     for just one limb, since no function ever makes zero space.  */
 	  SIZ(rem) = ns >= 0 ? 1 : -1;
-	  PTR(rem)[0] = rl;
+	  MPZ_NEWALLOC (rem, 1)[0] = rl;
 	}
       qn = nn - (qp[nn - 1] == 0);
     }
diff --git a/mpz/tdiv_r_ui.c b/mpz/tdiv_r_ui.c
index 30addd6db..7b034a3b8 100644
--- a/mpz/tdiv_r_ui.c
+++ b/mpz/tdiv_r_ui.c
@@ -64,7 +64,7 @@ mpz_tdiv_r_ui (mpz_ptr rem, mpz_srcptr dividend, unsigned long int divisor)
 	{
 	  rl = np[0];
 	  SIZ(rem) = ns >= 0 ? 1 : -1;
-	  PTR(rem)[0] = rl;
+	  MPZ_NEWALLOC (rem, 1)[0] = rl;
 	  return rl;
 	}
 
@@ -88,10 +88,8 @@ mpz_tdiv_r_ui (mpz_ptr rem, mpz_srcptr dividend, unsigned long int divisor)
 	SIZ(rem) = 0;
       else
 	{
-	  /* Store the single-limb remainder.  We don't check if there's space
-	     for just one limb, since no function ever makes zero space.  */
 	  SIZ(rem) = ns >= 0 ? 1 : -1;
-	  PTR(rem)[0] = rl;
+	  MPZ_NEWALLOC (rem, 1)[0] = rl;
 	}
     }
 
diff --git a/mpz/ui_sub.c b/mpz/ui_sub.c
index 579a30079..0730cf72f 100644
--- a/mpz/ui_sub.c
+++ b/mpz/ui_sub.c
@@ -52,11 +52,8 @@ mpz_ui_sub (mpz_ptr w, unsigned long int uval, mpz_srcptr v)
     }
 #endif
 
-  vp = PTR(v);
   vn = SIZ(v);
 
-  wp = PTR(w);
-
   if (vn > 1)
     {
       wp = MPZ_REALLOC (w, vn);
@@ -64,24 +61,22 @@ mpz_ui_sub (mpz_ptr w, unsigned long int uval, mpz_srcptr v)
       mpn_sub_1 (wp, vp, vn, (mp_limb_t) uval);
       wn = -(vn - (wp[vn - 1] == 0));
     }
-  else if (vn == 1)
+  else if (vn >= 0)
     {
-      if (uval >= vp[0])
+      mp_limb_t vp0;
+      vp0 = PTR (v)[0] & - (mp_limb_t) vn;
+      wp = MPZ_NEWALLOC (w, 1);
+      if (uval >= vp0)
 	{
-	  wp[0] = uval - vp[0];
+	  wp[0] = uval - vp0;
 	  wn = wp[0] != 0;
 	}
       else
 	{
-	  wp[0] = vp[0] - uval;
+	  wp[0] = vp0 - uval;
 	  wn = -1;
 	}
     }
-  else if (vn == 0)
-    {
-      wp[0] = uval;
-      wn = uval != 0;
-    }
   else /* (vn < 0) */
     {
       vn = -vn;