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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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1
Lib/test/test_peepholer.py
View File

@ -135,6 +135,7 @@ class TestTranforms(unittest.TestCase):
def test_set_conversion(self): def test_set_conversion(self):
for line in ( for line in (
'x in [1,2,3]',
'x in (1,2,3)', 'x in (1,2,3)',
'x not in (1,2,3)', 'x not in (1,2,3)',
'not x in (1,2,3)', 'not x 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 The consts table must still be in list form so that the
new constant (c1, c2, ... cn) can be appended. new constant (c1, c2, ... cn) can be appended.
Called with codestr pointing to the first LOAD_CONST. 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 static int
tuple_of_constants(unsigned char *codestr, int n, PyObject *consts) 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 */ /* Pre-conditions */
assert(PyList_CheckExact(consts)); 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); assert(GETARG(codestr, (n*3)) == n);
for (i=0 ; i<n ; i++) for (i=0 ; i<n ; i++)
assert(codestr[i*3] == LOAD_CONST); assert(codestr[i*3] == LOAD_CONST);
@ -753,24 +755,28 @@ optimize_code(PyObject *code, PyObject* consts, PyObject *names, PyObject *linen
cumlc = 0; cumlc = 0;
break; 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. Skip over BUILD_SEQN 1 UNPACK_SEQN 1.
Replace BUILD_SEQN 2 UNPACK_SEQN 2 with ROT2. Replace BUILD_SEQN 2 UNPACK_SEQN 2 with ROT2.
Replace BUILD_SEQN 3 UNPACK_SEQN 3 with ROT3 ROT2. */ Replace BUILD_SEQN 3 UNPACK_SEQN 3 with ROT3 ROT2. */
case BUILD_TUPLE: case BUILD_TUPLE:
case BUILD_LIST:
j = GETARG(codestr, i); j = GETARG(codestr, i);
h = i - 3 * j; h = i - 3 * j;
if (h >= 0 && if (h >= 0 &&
j <= lastlc && 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)) { tuple_of_constants(&codestr[h], j, consts)) {
assert(codestr[i] == LOAD_CONST); assert(codestr[i] == LOAD_CONST);
cumlc = 1; cumlc = 1;
break; break;
} }
/* Intentional fallthrough */
case BUILD_LIST:
j = GETARG(codestr, i);
if (codestr[i+3] != UNPACK_SEQUENCE || if (codestr[i+3] != UNPACK_SEQUENCE ||
!ISBASICBLOCK(blocks,i,6) || !ISBASICBLOCK(blocks,i,6) ||
j != GETARG(codestr, i+3)) j != GETARG(codestr, i+3))