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
diff --git a/Python/compile.c b/Python/compile.c
index 193d520..3b0c53f 100644
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -729,6 +729,8 @@
return -1;
case STORE_SUBSCR:
return -3;
+ case STORE_MAP:
+ return -2;
case DELETE_SUBSCR:
return -2;
@@ -2926,13 +2928,11 @@
/* We must arrange things just right for STORE_SUBSCR.
It wants the stack to look like (value) (dict) (key) */
for (i = 0; i < n; i++) {
- ADDOP(c, DUP_TOP);
VISIT(c, expr,
(expr_ty)asdl_seq_GET(e->v.Dict.values, i));
- ADDOP(c, ROT_TWO);
VISIT(c, expr,
(expr_ty)asdl_seq_GET(e->v.Dict.keys, i));
- ADDOP(c, STORE_SUBSCR);
+ ADDOP(c, STORE_MAP);
}
break;
case ListComp_kind: