Speed-up dictionary constructor by about 10%. New opcode, STORE_MAP saves the compiler from awkward stack manipulations and specializes for dicts using PyDict_SetItem instead of PyObject_SetItem. Old disassembly: 0 BUILD_MAP 0 3 DUP_TOP 4 LOAD_CONST 1 (1) 7 ROT_TWO 8 LOAD_CONST 2 ('x') 11 STORE_SUBSCR 12 DUP_TOP 13 LOAD_CONST 3 (2) 16 ROT_TWO 17 LOAD_CONST 4 ('y') 20 STORE_SUBSCR New disassembly: 0 BUILD_MAP 0 3 LOAD_CONST 1 (1) 6 LOAD_CONST 2 ('x') 9 STORE_MAP 10 LOAD_CONST 3 (2) 13 LOAD_CONST 4 ('y') 16 STORE_MAP

--- a/Python/import.c	Tue Dec 18 09:12:10 2007 +0000
+++ b/Python/import.c	Tue Dec 18 18:26:18 2007 +0000
@@ -66,10 +66,10 @@
        Python 2.5c1: 62121 (fix wrong lnotab with for loops and
        			    storing constants that should have been removed)
        Python 2.5c2: 62131 (fix wrong code: for x, in ... in listcomp/genexp)
-       Python 2.6a0: 62141 (peephole optimizations)
+       Python 2.6a0: 62151 (peephole optimizations and STORE_MAP opcode)
 .
 */
-#define MAGIC (62141 | ((long)'\r'<<16) | ((long)'\n'<<24))
+#define MAGIC (62151 | ((long)'\r'<<16) | ((long)'\n'<<24))
 
 /* Magic word as global; note that _PyImport_Init() can change the
    value of this global to accommodate for alterations of how the