[pypy-svn] r78837 - pypy/extradoc/planning

[fijal at codespeak.net]

Author: fijal
Date: Sun Nov  7 20:54:10 2010
New Revision: 78837

Modified:
   pypy/extradoc/planning/jit.txt
Log:
Add an item before I forget


Modified: pypy/extradoc/planning/jit.txt
==============================================================================
--- pypy/extradoc/planning/jit.txt	(original)
+++ pypy/extradoc/planning/jit.txt	Sun Nov  7 20:54:10 2010
@@ -86,6 +86,20 @@
 
 - xxx (find more examples :-)
 
+BACKEND TASKS
+-------------
+
+Look into avoiding double load of memory into register on 64bit.
+In case we want to first read a value, increment it and store (for example),
+we end up with double load of memory into register. Like:
+
+movabs 0xsomemem,r11
+mov    (r11), r10
+add    0x1, r10
+movabs 0xsomemem,r11
+mov    r10, (r11)
+
+(second movabs could have been avoided)
 
 LATER (maybe) TASKS
 -------------------