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Adopt Skip's idea to optimize lists of constants in the context 

of a "in" or "not in" test.
This commit is contained in:
Raymond Hettinger 2005-02-07 19:32:38 +00:00
parent fe59dc1bd8
commit 7fcb7869ba
2 changed files with 15 additions and 8 deletions
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3
Lib/test/test_peepholer.py
View File

@ -135,7 +135,8 @@ class TestTranforms(unittest.TestCase):
def test_set_conversion(self):
for line in (
'x in (1,2,3)',
'x in [1,2,3]',
'x in (1,2,3)',
'x not in (1,2,3)',
'not x in (1,2,3)',
'not x not in (1,2,3)',

20
Python/compile.c
View File

@ -397,7 +397,9 @@ intern_strings(PyObject *tuple)
The consts table must still be in list form so that the
new constant (c1, c2, ... cn) can be appended.
Called with codestr pointing to the first LOAD_CONST.
Bails out with no change if one or more of the LOAD_CONSTs is missing. */
Bails out with no change if one or more of the LOAD_CONSTs is missing.
Also works for BUILD_LIST when followed by an "in" or "not in" test.
*/
static int
tuple_of_constants(unsigned char *codestr, int n, PyObject *consts)
{
@ -406,7 +408,7 @@ tuple_of_constants(unsigned char *codestr, int n, PyObject *consts)
/* Pre-conditions */
assert(PyList_CheckExact(consts));
assert(codestr[n*3] == BUILD_TUPLE);
assert(codestr[n*3] == BUILD_TUPLE || codestr[n*3] == BUILD_LIST);
assert(GETARG(codestr, (n*3)) == n);
for (i=0 ; i<n ; i++)
assert(codestr[i*3] == LOAD_CONST);
@ -753,24 +755,28 @@ optimize_code(PyObject *code, PyObject* consts, PyObject *names, PyObject *linen
cumlc = 0;
break;
/* Try to fold tuples of constants.
/* Try to fold tuples of constants (includes a case for lists
which are only used for "in" and "not in" tests).
Skip over BUILD_SEQN 1 UNPACK_SEQN 1.
Replace BUILD_SEQN 2 UNPACK_SEQN 2 with ROT2.
Replace BUILD_SEQN 3 UNPACK_SEQN 3 with ROT3 ROT2. */
case BUILD_TUPLE:
case BUILD_LIST:
j = GETARG(codestr, i);
h = i - 3 * j;
if (h >= 0 &&
j <= lastlc &&
ISBASICBLOCK(blocks, h, 3*(j+1)) &&
(opcode == BUILD_TUPLE &&
ISBASICBLOCK(blocks, h, 3*(j+1)) ||
opcode == BUILD_LIST &&
codestr[i+3]==COMPARE_OP &&
ISBASICBLOCK(blocks, h, 3*(j+2)) &&
(GETARG(codestr,i+3)==6 || GETARG(codestr,i+3)==7)) &&
tuple_of_constants(&codestr[h], j, consts)) {
assert(codestr[i] == LOAD_CONST);
cumlc = 1;
break;
}
/* Intentional fallthrough */
case BUILD_LIST:
j = GETARG(codestr, i);
if (codestr[i+3] != UNPACK_SEQUENCE ||
!ISBASICBLOCK(blocks,i,6) ||
j != GETARG(codestr, i+3))