Author: georg.brandl
Date: Mon Jun 11 09:26:37 2007
New Revision: 55886
Modified:
python/branches/p3yk/Lib/test/test_peepholer.py
python/branches/p3yk/Python/compile.c
python/branches/p3yk/Python/peephole.c
Log:
Optimize access to True and False in the compiler (if True)
and the peepholer (LOAD_NAME True).
Modified: python/branches/p3yk/Lib/test/test_peepholer.py
==============================================================================
--- python/branches/p3yk/Lib/test/test_peepholer.py (original)
+++ python/branches/p3yk/Lib/test/test_peepholer.py Mon Jun 11 09:26:37 2007
@@ -39,16 +39,24 @@
asm = dis_single(line)
self.assert_(elem in asm)
- def test_none_as_constant(self):
- # LOAD_GLOBAL None --> LOAD_CONST None
+ def test_global_as_constant(self):
+ # LOAD_GLOBAL None/True/False --> LOAD_CONST None/True/False
def f(x):
None
+ None
return x
- asm = disassemble(f)
- for elem in ('LOAD_GLOBAL',):
- self.assert_(elem not in asm)
- for elem in ('LOAD_CONST', '(None)'):
- self.assert_(elem in asm)
+ def g(x):
+ True
+ return x
+ def h(x):
+ False
+ return x
+ for func, name in ((f, 'None'), (g, 'True'), (h, 'False')):
+ asm = disassemble(func)
+ for elem in ('LOAD_GLOBAL',):
+ self.assert_(elem not in asm)
+ for elem in ('LOAD_CONST', '('+name+')'):
+ self.assert_(elem in asm)
def f():
'Adding a docstring made this test fail in Py2.5.0'
return None
Modified: python/branches/p3yk/Python/compile.c
==============================================================================
--- python/branches/p3yk/Python/compile.c (original)
+++ python/branches/p3yk/Python/compile.c Mon Jun 11 09:26:37 2007
@@ -2948,6 +2948,7 @@
static int
expr_constant(expr_ty e)
{
+ char *id;
switch (e->kind) {
case Ellipsis_kind:
return 1;
@@ -2956,11 +2957,13 @@
case Str_kind:
return PyObject_IsTrue(e->v.Str.s);
case Name_kind:
- /* __debug__ is not assignable, so we can optimize
- * it away in if and while statements */
- if (strcmp(PyString_AS_STRING(e->v.Name.id),
- "__debug__") == 0)
- return ! Py_OptimizeFlag;
+ /* optimize away names that can't be reassigned */
+ id = PyString_AS_STRING(e->v.Name.id);
+ if (strcmp(id, "True") == 0) return 1;
+ if (strcmp(id, "False") == 0) return 0;
+ if (strcmp(id, "None") == 0) return 0;
+ if (strcmp(id, "__debug__") == 0)
+ return ! Py_OptimizeFlag;
/* fall through */
default:
return -1;
Modified: python/branches/p3yk/Python/peephole.c
==============================================================================
--- python/branches/p3yk/Python/peephole.c (original)
+++ python/branches/p3yk/Python/peephole.c Mon Jun 11 09:26:37 2007
@@ -257,6 +257,37 @@
return blocks;
}
+/* Helper to replace LOAD_NAME None/True/False with LOAD_CONST
+ Returns: 0 if no change, 1 if change, -1 if error */
+static int
+load_global(unsigned char *codestr, Py_ssize_t i, char *name, PyObject *consts)
+{
+ Py_ssize_t j;
+ PyObject *obj;
+ if (name == NULL)
+ return 0;
+ if (strcmp(name, "None") == 0)
+ obj = Py_None;
+ else if (strcmp(name, "True") == 0)
+ obj = Py_True;
+ else if (strcmp(name, "False") == 0)
+ obj = Py_False;
+ else
+ return 0;
+ for (j = 0; j < PyList_GET_SIZE(consts); j++) {
+ if (PyList_GET_ITEM(consts, j) == obj)
+ break;
+ }
+ if (j == PyList_GET_SIZE(consts)) {
+ if (PyList_Append(consts, obj) < 0)
+ return -1;
+ }
+ assert(PyList_GET_ITEM(consts, j) == obj);
+ codestr[i] = LOAD_CONST;
+ SETARG(codestr, i, j);
+ return 1;
+}
+
/* Perform basic peephole optimizations to components of a code object.
The consts object should still be in list form to allow new constants
to be appended.
@@ -371,25 +402,17 @@
codestr[i+3] = NOP;
break;
- /* Replace LOAD_GLOBAL/LOAD_NAME None
- with LOAD_CONST None */
+ /* Replace LOAD_GLOBAL/LOAD_NAME None/True/False
+ with LOAD_CONST None/True/False */
case LOAD_NAME:
case LOAD_GLOBAL:
j = GETARG(codestr, i);
name =
PyString_AsString(PyTuple_GET_ITEM(names, j));
- if (name == NULL || strcmp(name, "None") != 0)
+ h = load_global(codestr, i, name, consts);
+ if (h < 0)
+ goto exitUnchanged;
+ else if (h == 0)
continue;
- for (j=0 ; j < PyList_GET_SIZE(consts) ; j++) {
- if (PyList_GET_ITEM(consts, j) ==
Py_None)
- break;
- }
- if (j == PyList_GET_SIZE(consts)) {
- if (PyList_Append(consts, Py_None) ==
-1)
- goto exitUnchanged;
- }
- assert(PyList_GET_ITEM(consts, j) == Py_None);
- codestr[i] = LOAD_CONST;
- SETARG(codestr, i, j);
cumlc = lastlc + 1;
break;
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