From 2314c1bf476dbef2bd5904d262410dff230e1661 Mon Sep 17 00:00:00 2001
From: akr <akr@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Thu, 18 Jul 2013 12:58:46 +0000
Subject: [PATCH] * bignum.c (bary_sq_fast): Specialize the last iteration of
 the   outer loop.   (bigfixize): A condition simplified.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42044 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 ChangeLog |  6 ++++++
 bignum.c  | 25 ++++++++++++++++++++-----
 2 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 33b8af84d58f54..ac6f45428da525 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Thu Jul 18 21:30:50 2013  Tanaka Akira  <akr@fsij.org>
+
+	* bignum.c (bary_sq_fast): Specialize the last iteration of the
+	  outer loop.
+	  (bigfixize): A condition simplified.
+
 Thu Jul 18 21:15:41 2013  Masaki Matsushita  <glass.saga@gmail.com>
 
 	* array.c (rb_ary_equal): compare RARRAY_PTR() for performance
diff --git a/bignum.c b/bignum.c
index 22695a45a83729..52086f51cdfbb5 100644
--- a/bignum.c
+++ b/bignum.c
@@ -1605,7 +1605,11 @@ bary_sq_fast(BDIGIT *zds, size_t zn, BDIGIT *xds, size_t xn)
     assert(xn * 2 <= zn);
 
     BDIGITS_ZERO(zds, zn);
-    for (i = 0; i < xn; i++) {
+
+    if (xn == 0)
+        return;
+
+    for (i = 0; i < xn-1; i++) {
 	v = (BDIGIT_DBL)xds[i];
 	if (!v)
             continue;
@@ -1625,11 +1629,22 @@ bary_sq_fast(BDIGIT *zds, size_t zn, BDIGIT *xds, size_t xn)
 	    c += (BDIGIT_DBL)zds[i + xn];
 	    zds[i + xn] = BIGLO(c);
 	    c = BIGDN(c);
-            assert(c == 0 || i != xn-1);
-            if (c && i != xn-1)
+            if (c)
                 zds[i + xn + 1] += (BDIGIT)c;
 	}
     }
+
+    /* i == xn-1 */
+    v = (BDIGIT_DBL)xds[i];
+    if (!v)
+        return;
+    c = (BDIGIT_DBL)zds[i + i] + v * v;
+    zds[i + i] = BIGLO(c);
+    c = BIGDN(c);
+    if (c) {
+        c += (BDIGIT_DBL)zds[i + xn];
+        zds[i + xn] = BIGLO(c);
+    }
 }
 
 VALUE
@@ -2336,11 +2351,11 @@ bigfixize(VALUE x)
         int i = (int)len;
         u = 0;
         while (i--) {
-            u = (long)(BIGUP(u) + ds[i]);
+            u = (unsigned long)(BIGUP(u) + ds[i]);
         }
     }
 #else /* SIZEOF_BDIGITS >= SIZEOF_LONG */
-    if (1 < len || LONG_MAX < ds[0])
+    if (1 < len)
         goto return_big;
     else
         u = ds[0];