From: Paul Eggert <eggert@cs.ucla.edu>
Date: Wed, 2 Jul 2025 21:46:00 +0000 (-0700)
Subject: factor: tune submod2
X-Git-Tag: v9.8~194
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=73bb62f7dfe25d9beac0cc5e8e55ad708f0dc5e5;p=thirdparty%2Fcoreutils.git

factor: tune submod2

* src/factor.c (submod2): Use ckd_sub to subtract by hand rather
than using sub_ddmmss plus a compare.  This speeds things up a
bit, on x86-64 with GCC 15 anyway.
---

diff --git a/src/factor.c b/src/factor.c
index cdb31dda0b..79eeabe829 100644
--- a/src/factor.c
+++ b/src/factor.c
@@ -428,8 +428,9 @@ gt2 (mp_limb_t ah, mp_limb_t al, mp_limb_t bh, mp_limb_t bl)
   } while (0)
 #define submod2(r1, r0, a1, a0, b1, b0, n1, n0)                         \
   do {                                                                  \
-    sub_ddmmss (r1, r0, a1, a0, b1, b0);				\
-    if ((r1) >> (W_TYPE_SIZE - 1) != 0)					\
+    bool _v1 = ckd_sub (&(r1), a1, b1);					\
+    mp_limb_t _v0 = ckd_sub (&(r0), a0, b0);				\
+    if (_v1 | ckd_sub (&(r1), r1, _v0))					\
       add_ssaaaa (r1, r0, r1, r0, n1, n0);				\
   } while (0)