[Python-checkins] cpython: Optimization guides suggest copying memory in an ascending direction when

[raymond.hettinger]

https://hg.python.org/cpython/rev/673191aa1724
changeset:   94460:673191aa1724
parent:      94458:31dc5a40d2ab
user:        Raymond Hettinger <python at rcn.com>
date:        Sun Feb 01 22:53:41 2015 -0800
summary:
  Optimization guides suggest copying memory in an ascending direction when possible.

files:
  Modules/_collectionsmodule.c |  6 +++---
  1 files changed, 3 insertions(+), 3 deletions(-)


diff --git a/Modules/_collectionsmodule.c b/Modules/_collectionsmodule.c
--- a/Modules/_collectionsmodule.c
+++ b/Modules/_collectionsmodule.c
@@ -534,13 +534,13 @@
             if (m > leftindex)
                 m = leftindex;
             assert (m > 0 && m <= len);
-            src = &rightblock->data[rightindex];
-            dest = &leftblock->data[leftindex - 1];
             rightindex -= m;
             leftindex -= m;
+            src = &rightblock->data[rightindex + 1];
+            dest = &leftblock->data[leftindex];
             n -= m;
             do {
-                *(dest--) = *(src--);
+                *(dest++) = *(src++);
             } while (--m);
         }
         if (rightindex == -1) {

-- 
Repository URL: https://hg.python.org/cpython