Index: Lib/opcode.py
===================================================================
RCS file: /cvsroot/python/python/dist/src/Lib/opcode.py,v
retrieving revision 1.6
diff -u -r1.6 opcode.py
--- Lib/opcode.py	21 Jun 2004 16:31:13 -0000	1.6
+++ Lib/opcode.py	20 Feb 2005 15:27:12 -0000
@@ -130,6 +130,7 @@
 name_op('DELETE_NAME', 91)      # ""
 def_op('UNPACK_SEQUENCE', 92)   # Number of tuple items
 jrel_op('FOR_ITER', 93)
+name_op('DUP_STORE_NAME', 94)   # Index in name list
 
 name_op('STORE_ATTR', 95)       # Index in name list
 name_op('DELETE_ATTR', 96)      # ""
@@ -166,6 +167,8 @@
 haslocal.append(125)
 def_op('DELETE_FAST', 126)      # Local variable number
 haslocal.append(126)
+def_op('DUP_STORE_FAST', 127)   # Local variable number
+haslocal.append(127)
 
 def_op('RAISE_VARARGS', 130)    # Number of raise arguments (1, 2, or 3)
 def_op('CALL_FUNCTION', 131)    # #args + (#kwargs << 8)
Index: Include/opcode.h
===================================================================
RCS file: /cvsroot/python/python/dist/src/Include/opcode.h,v
retrieving revision 2.45
diff -u -r2.45 opcode.h
--- Include/opcode.h	21 Jun 2004 16:31:15 -0000	2.45
+++ Include/opcode.h	20 Feb 2005 15:27:12 -0000
@@ -89,6 +89,7 @@
 #define DELETE_NAME	91	/* "" */
 #define UNPACK_SEQUENCE	92	/* Number of sequence items */
 #define FOR_ITER	93
+#define DUP_STORE_NAME  94	/* Index in name list */
 
 #define STORE_ATTR	95	/* Index in name list */
 #define DELETE_ATTR	96	/* "" */
@@ -120,6 +121,7 @@
 #define LOAD_FAST	124	/* Local variable number */
 #define STORE_FAST	125	/* Local variable number */
 #define DELETE_FAST	126	/* Local variable number */
+#define DUP_STORE_FAST  127	/* Local variable number */
 
 #define RAISE_VARARGS	130	/* Number of raise arguments (1, 2 or 3) */
 /* CALL_FUNCTION_XXX opcodes defined below depend on this definition */
Index: Python/ceval.c
===================================================================
RCS file: /cvsroot/python/python/dist/src/Python/ceval.c,v
retrieving revision 2.421
diff -u -r2.421 ceval.c
--- Python/ceval.c	18 Jan 2005 15:56:11 -0000	2.421
+++ Python/ceval.c	20 Feb 2005 15:27:14 -0000
@@ -926,6 +926,12 @@
 			Py_DECREF(v);
 			goto fast_next_opcode;
 
+		case DUP_STORE_FAST:
+			v = TOP();
+			Py_INCREF(v);
+			SETLOCAL(oparg, v);
+			goto fast_next_opcode;
+
 		case ROT_TWO:
 			v = TOP();
 			w = SECOND();
@@ -1712,6 +1718,23 @@
 				     PyObject_REPR(w));
 			break;
 
+		case DUP_STORE_NAME:
+			w = GETITEM(names, oparg);
+			v = TOP();
+			if ((x = f->f_locals) != NULL) {
+				if (PyDict_CheckExact(x))
+					err = PyDict_SetItem(x, w, v);
+				else
+					err = PyObject_SetItem(x, w, v);
+				if (err == 0) continue;
+				break;
+			}
+			STACKADJ(-1);
+			PyErr_Format(PyExc_SystemError,
+				     "no locals found when storing %s",
+				     PyObject_REPR(w));
+			break;
+
 		case DELETE_NAME:
 			w = GETITEM(names, oparg);
 			if ((x = f->f_locals) != NULL) {
Index: Python/compile.c
===================================================================
RCS file: /cvsroot/python/python/dist/src/Python/compile.c,v
retrieving revision 2.345
diff -u -r2.345 compile.c
--- Python/compile.c	20 Feb 2005 12:41:32 -0000	2.345
+++ Python/compile.c	20 Feb 2005 15:27:17 -0000
@@ -744,6 +744,42 @@
 			}
 			break;
 
+		/* Replace STORE_FAST x LOAD_FAST x with DUP_STORE_FAST x */
+		case STORE_FAST:
+			j = GETARG(codestr, i);
+			if (codestr[i+3] == LOAD_FAST  &&
+			    GETARG(codestr, i+3) == j  &&
+			    ISBASICBLOCK(blocks,i,6)) {
+				codestr[i] = DUP_STORE_FAST;
+				memset(codestr+i+3, NOP, 3);
+			}
+			break;
+
+		/* Replace STORE_NAME x LOAD_NAME x with DUP_STORE_NAME x */
+		case STORE_NAME:
+			j = GETARG(codestr, i);
+			if (codestr[i+3] == LOAD_NAME  &&
+			    GETARG(codestr, i+3) == j  &&
+			    ISBASICBLOCK(blocks,i,6)) {
+				codestr[i] = DUP_STORE_NAME;
+				memset(codestr+i+3, NOP, 3);
+			}
+			break;
+
+		/* Replace DUP_TOP STORE_NAME/FAST with DUP_STORE_NAME/FAST.
+		   This arises in chained assignments like:  x = y = f(). */
+		case DUP_TOP:
+			if (codestr[i+1] == STORE_FAST  &&
+			    ISBASICBLOCK(blocks,i,4)) {
+				codestr[i] = NOP;
+				codestr[i+1] = DUP_STORE_FAST;
+			} else if (codestr[i+1] == STORE_NAME  &&
+			    ISBASICBLOCK(blocks,i,4)) {
+				codestr[i] = NOP;
+				codestr[i+1] = DUP_STORE_NAME;
+			}
+			break;
+
 		/* Skip over LOAD_CONST trueconst  JUMP_IF_FALSE xx  POP_TOP */
 		case LOAD_CONST:
 			cumlc = lastlc + 1;
Index: Python/import.c
===================================================================
RCS file: /cvsroot/python/python/dist/src/Python/import.c,v
retrieving revision 2.240
diff -u -r2.240 import.c
--- Python/import.c	7 Oct 2004 06:46:25 -0000	2.240
+++ Python/import.c	20 Feb 2005 15:27:18 -0000
@@ -50,8 +50,9 @@
        Python 2.4a0: 62041
        Python 2.4a3: 62051
        Python 2.4b1: 62061
+       Python 2.5a0  62071
 */
-#define MAGIC (62061 | ((long)'\r'<<16) | ((long)'\n'<<24))
+#define MAGIC (62071 | ((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
Index: Lib/test/test_peepholer.py
===================================================================
RCS file: /cvsroot/python/python/dist/src/Lib/test/test_peepholer.py,v
retrieving revision 1.12
diff -u -r1.12 test_peepholer.py
--- Lib/test/test_peepholer.py	20 Feb 2005 12:46:54 -0000	1.12
+++ Lib/test/test_peepholer.py	20 Feb 2005 15:27:18 -0000
@@ -161,7 +161,23 @@
         self.assert_('(None)' not in asm)
         self.assertEqual(asm.split().count('RETURN_VALUE'), 1)
 
+    def test_dup_store(self):
+        def f():
+            x = 3
+            y = x
+        asm = disassemble(f)
+        self.assert_('DUP_STORE_FAST' in asm)
 
+        asm = dis_single('x=3; y=x')
+        self.assert_('DUP_STORE_NAME' in asm)
+
+        def f():
+            x = y = 1
+        asm = disassemble(f)
+        self.assert_('DUP_STORE_FAST' in asm)
+
+        asm = dis_single('x = y = 1')
+        self.assert_('DUP_STORE_NAME' in asm)        
 
 def test_main(verbose=None):
     import sys