From 3b1f672fb644138ab8f77a418b3e245ab6085d13 Mon Sep 17 00:00:00 2001
From: Sergey B Kirpichev <skirpichev@gmail.com>
Date: Thu, 19 Feb 2026 02:23:38 +0300
Subject: [PATCH 1/4] Avoid static zz_t initialization in heap()

---
 gmp.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/gmp.c b/gmp.c
index 6c6d1534..8a806cfb 100644
--- a/gmp.c
+++ b/gmp.c
@@ -850,8 +850,11 @@ hash(PyObject *self)
         return u->hash_cache;
     }
 
-    zz_digit_t digits[1];
-    zz_t w = {false, 1, 1, digits};
+    zz_t w;
+
+    if (zz_init(&w)) {
+        return -1; /* LCOV_EXCL_LINE */
+    }
 
     assert((int64_t)INT64_MAX > pyhash_modulus);
     (void)zz_div(&u->z, (int64_t)pyhash_modulus, NULL, &w);
@@ -860,6 +863,7 @@ hash(PyObject *self)
 
     assert(sizeof(Py_hash_t) == 8);
     (void)zz_get(&w, (int64_t *)&r);
+    zz_clear(&w);
     if (zz_isneg(&u->z) && r) {
         r = -(pyhash_modulus - r);
     }

From ede9094fee6dafced9631b48272fcb7638dce72c Mon Sep 17 00:00:00 2001
From: Sergey B Kirpichev <skirpichev@gmail.com>
Date: Thu, 19 Feb 2026 04:43:22 +0300
Subject: [PATCH 2/4] Use zz_sizeof()

---
 gmp.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/gmp.c b/gmp.c
index 8a806cfb..7150f278 100644
--- a/gmp.c
+++ b/gmp.c
@@ -12,7 +12,7 @@
 #else
 #  define MAX_CACHE_SIZE 0
 #endif
-#define MAX_CACHED_NDIGITS 16
+#define MAX_CACHED_SIZEOF 256
 
 typedef struct {
     MPZ_Object *gmp_cache[MAX_CACHE_SIZE + 1];
@@ -660,7 +660,7 @@ dealloc(PyObject *self)
     MPZ_Object *u = (MPZ_Object *)self;
 
     if (global.gmp_cache_size < MAX_CACHE_SIZE
-        && (u->z).alloc <= MAX_CACHED_NDIGITS
+        && zz_sizeof(&u->z) <= MAX_CACHED_SIZEOF
         && MPZ_CheckExact(self))
     {
         global.gmp_cache[global.gmp_cache_size++] = u;
@@ -1884,8 +1884,8 @@ __sizeof__(PyObject *self, PyObject *Py_UNUSED(ignored))
 {
     MPZ_Object *u = (MPZ_Object *)self;
 
-    return PyLong_FromSize_t(sizeof(MPZ_Object)
-                             + (size_t)(u->z).alloc*sizeof(zz_digit_t));
+    return PyLong_FromSize_t(sizeof(MPZ_Object) - sizeof(zz_t)
+                             + zz_sizeof(&u->z));
 }
 
 static PyObject *

From 6663edfe08249af081dcec7407395f44c79ad97d Mon Sep 17 00:00:00 2001
From: Sergey B Kirpichev <skirpichev@gmail.com>
Date: Thu, 19 Feb 2026 14:16:57 +0300
Subject: [PATCH 3/4] Add collatz2() in bench/collatz.py

---
 bench/collatz.py | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/bench/collatz.py b/bench/collatz.py
index 3b08a4a3..6c0f63fc 100644
--- a/bench/collatz.py
+++ b/bench/collatz.py
@@ -36,8 +36,17 @@ def collatz1(n):
         total += 1
     return total
 
+def collatz2(n):
+    total = 0
+    n = mpz(n)
+    while n > 1:
+        n = n*3 + 1 if n & one else n//2
+        total += 1
+    return total
+
+
 runner = pyperf.Runner()
-for f in [collatz0, collatz1]:
+for f in [collatz0, collatz1, collatz2]:
     for v in ["97", "871", "(1<<128)+31"]:
         h = f"{f.__name__}({v})"
         i = eval(v)

From 33cfa0e54b9e1657a8da4bf8dbfd962094252933 Mon Sep 17 00:00:00 2001
From: Sergey B Kirpichev <skirpichev@gmail.com>
Date: Fri, 20 Feb 2026 07:07:46 +0300
Subject: [PATCH 4/4] Use libzz v0.9.0a4

---
 .readthedocs.yaml          | 2 +-
 scripts/cibw_before_all.sh | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/.readthedocs.yaml b/.readthedocs.yaml
index 289e1887..638a47f6 100644
--- a/.readthedocs.yaml
+++ b/.readthedocs.yaml
@@ -12,7 +12,7 @@ build:
       pre_create_environment:
         - |
           PREFIX=$(pwd)/.local
-          ZZ_VERSION=0.9.0a3
+          ZZ_VERSION=0.9.0a4
           ZZ_DIR=zz-${ZZ_VERSION}
           GITHUB_URL=https://github.com/diofant/zz/releases/download/
           ZZ_URL=${GITHUB_URL}v${ZZ_VERSION}/${ZZ_DIR}.tar.gz
diff --git a/scripts/cibw_before_all.sh b/scripts/cibw_before_all.sh
index fbcc22a1..5f7ec6ba 100644
--- a/scripts/cibw_before_all.sh
+++ b/scripts/cibw_before_all.sh
@@ -53,7 +53,7 @@ make --silent all install
 
 cd ..
 
-ZZ_VERSION=0.9.0a3
+ZZ_VERSION=0.9.0a4
 ZZ_DIR=zz-${ZZ_VERSION}
 ZZ_URL=https://github.com/diofant/zz/releases/download/v${ZZ_VERSION}/${ZZ_DIR}.tar.gz