kopia lustrzana https://github.com/micropython/micropython
py/parse: Allow const types other than int to optimise as true/false.
Allows optimisation of cases like:
import micropython
_DEBUG = micropython.const(False)
if _DEBUG:
print('Debugging info')
Previously the 'if' statement was only optimised out if the type of the
const() argument was integer.
The change is implemented in a way that makes the compiler slightly smaller
(-16 bytes on PYBV11) but compilation will also be very slightly slower.
As a bonus, if const support is enabled then the compiler can now optimise
const truthy/falsey expressions of other types, like:
while "something":
pass
... unclear if that is useful, but perhaps it could be.
Signed-off-by: Angus Gratton <angus@redyak.com.au>
pull/9411/head
Angus Gratton
Damien George
rodzic
f91ebf6fa9
commit
25ff5b52d9
28
py/parse.c
28
py/parse.c
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@ -334,16 +334,6 @@ STATIC uint8_t peek_rule(parser_t *parser, size_t n) {
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}
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#endif
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bool mp_parse_node_is_const_false(mp_parse_node_t pn) {
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return MP_PARSE_NODE_IS_TOKEN_KIND(pn, MP_TOKEN_KW_FALSE)
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|| (MP_PARSE_NODE_IS_SMALL_INT(pn) && MP_PARSE_NODE_LEAF_SMALL_INT(pn) == 0);
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}
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bool mp_parse_node_is_const_true(mp_parse_node_t pn) {
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return MP_PARSE_NODE_IS_TOKEN_KIND(pn, MP_TOKEN_KW_TRUE)
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|| (MP_PARSE_NODE_IS_SMALL_INT(pn) && MP_PARSE_NODE_LEAF_SMALL_INT(pn) != 0);
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}
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bool mp_parse_node_get_int_maybe(mp_parse_node_t pn, mp_obj_t *o) {
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if (MP_PARSE_NODE_IS_SMALL_INT(pn)) {
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*o = MP_OBJ_NEW_SMALL_INT(MP_PARSE_NODE_LEAF_SMALL_INT(pn));
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@ -427,6 +417,24 @@ STATIC mp_obj_t mp_parse_node_convert_to_obj(mp_parse_node_t pn) {
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}
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#endif
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STATIC bool parse_node_is_const_bool(mp_parse_node_t pn, bool value) {
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// Returns true if 'pn' is a constant whose boolean value is equivalent to 'value'
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#if MICROPY_COMP_CONST_TUPLE || MICROPY_COMP_CONST
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return mp_parse_node_is_const(pn) && mp_obj_is_true(mp_parse_node_convert_to_obj(pn)) == value;
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#else
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return MP_PARSE_NODE_IS_TOKEN_KIND(pn, value ? MP_TOKEN_KW_TRUE : MP_TOKEN_KW_FALSE)
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|| (MP_PARSE_NODE_IS_SMALL_INT(pn) && !!MP_PARSE_NODE_LEAF_SMALL_INT(pn) == value);
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#endif
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}
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bool mp_parse_node_is_const_false(mp_parse_node_t pn) {
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return parse_node_is_const_bool(pn, false);
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}
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bool mp_parse_node_is_const_true(mp_parse_node_t pn) {
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return parse_node_is_const_bool(pn, true);
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}
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size_t mp_parse_node_extract_list(mp_parse_node_t *pn, size_t pn_kind, mp_parse_node_t **nodes) {
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if (MP_PARSE_NODE_IS_NULL(*pn)) {
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*nodes = NULL;
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@ -0,0 +1,69 @@
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# cmdline: -v -v
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# Test constant-related bytecode optimisations
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# (constant folding, compile-time if/while evaluation, etc.)
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from micropython import const
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import sys
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try:
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sys.settrace
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# if MICROPY_PY_SYS_SETTRACE is enabled, compile-time const optimizations
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# are disabled so the bytecode output is very different
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print("SKIP")
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raise SystemExit
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except AttributeError:
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pass
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_STR = const("foo")
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_EMPTY_TUPLE = const(())
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_TRUE = const(True)
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_FALSE = const(False)
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_SMALLINT = const(33)
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_ZERO = const(0)
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# Bytecode generated for these if/while statements should contain no JUMP_IF
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# and no instances of string 'Eliminated'
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if _STR or _EMPTY_TUPLE:
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print("Kept")
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if _STR and _EMPTY_TUPLE:
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print("Eliminated")
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if _TRUE:
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print("Kept")
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if _SMALLINT:
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print("Kept")
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if _ZERO and _SMALLINT:
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print("Eliminated")
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if _FALSE:
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print("Eliminated")
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while _SMALLINT:
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print("Kept")
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break
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while _ZERO:
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print("Eliminated")
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while _FALSE:
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print("Eliminated")
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# These values are stored in variables, and therefore bytecode will contain JUMP_IF
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a = _EMPTY_TUPLE or _STR
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if a == _STR:
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print("Kept")
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b = _SMALLINT and _STR
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if b == _STR:
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print("Kept")
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# The compiler is also unable to optimise these expressions, even though the arguments are const,
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# so these also contain JUMP_IF
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if (_EMPTY_TUPLE or _STR) == _STR:
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print("Kept")
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if (_EMPTY_TUPLE and _STR) == _STR:
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print("Not Eliminated")
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if (not _STR) == _FALSE:
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print("Kept")
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assert True
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@ -0,0 +1,160 @@
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File cmdline/cmd_showbc_const.py, code block '<module>' (descriptor: \.\+, bytecode @\.\+ 198 bytes)
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Raw bytecode (code_info_size=40, bytecode_size=158):
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2c 4c 01 60 2c 46 22 65 27 4a 83 0c 20 27 40 20
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27 20 27 40 60 20 27 24 40 60 40 24 27 47 24 27
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67 40 27 47 27 47 26 47 80 10 02 2a 01 1b 03 1c
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02 16 02 59 80 51 1b 04 16 04 48 0f 11 04 13 05
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59 11 09 10 06 34 01 59 11 0a 65 57 11 0b df 44
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43 59 4a 01 5d 11 09 10 07 34 01 59 11 09 10 07
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34 01 59 11 09 10 07 34 01 59 11 09 10 07 34 01
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59 42 42 42 35 23 00 16 0c 11 0c 23 00 d9 44 47
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11 09 10 07 34 01 59 23 00 16 0d 11 0d 23 00 d9
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44 47 11 09 10 07 34 01 59 23 00 23 00 d9 44 47
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11 09 10 07 34 01 59 23 01 23 00 d9 44 47 11 09
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23 02 34 01 59 50 23 03 d9 44 47 11 09 10 07 34
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01 59 42 40 51 63
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arg names:
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(N_STATE 6)
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(N_EXC_STACK 1)
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bc=0 line=1
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bc=0 line=4
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bc=12 line=5
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bc=18 line=7
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bc=20 line=8
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bc=25 line=11
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bc=32 line=12
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bc=42 line=14
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bc=45 line=26
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bc=45 line=27
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bc=52 line=28
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bc=52 line=30
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bc=52 line=31
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bc=59 line=32
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bc=59 line=33
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bc=66 line=34
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bc=66 line=36
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bc=66 line=39
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bc=66 line=40
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bc=73 line=41
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bc=77 line=42
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bc=77 line=44
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bc=77 line=47
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bc=77 line=49
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bc=81 line=50
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bc=88 line=51
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bc=95 line=53
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bc=99 line=54
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bc=106 line=55
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bc=113 line=58
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bc=113 line=60
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bc=120 line=61
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bc=127 line=63
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bc=134 line=64
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bc=141 line=66
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bc=147 line=67
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bc=154 line=69
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00 LOAD_CONST_SMALL_INT 0
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01 LOAD_CONST_STRING 'const'
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03 BUILD_TUPLE 1
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05 IMPORT_NAME 'micropython'
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07 IMPORT_FROM 'const'
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09 STORE_NAME const
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11 POP_TOP
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12 LOAD_CONST_SMALL_INT 0
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13 LOAD_CONST_NONE
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14 IMPORT_NAME 'sys'
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16 STORE_NAME sys
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18 SETUP_EXCEPT 35
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20 LOAD_NAME sys
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22 LOAD_ATTR settrace
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24 POP_TOP
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25 LOAD_NAME print
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27 LOAD_CONST_STRING 'SKIP'
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29 CALL_FUNCTION n=1 nkw=0
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31 POP_TOP
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32 LOAD_NAME SystemExit
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34 RAISE_OBJ
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35 DUP_TOP
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36 LOAD_NAME AttributeError
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38 BINARY_OP 8
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39 POP_JUMP_IF_FALSE 44
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41 POP_TOP
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42 POP_EXCEPT_JUMP 45
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44 END_FINALLY
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45 LOAD_NAME print
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47 LOAD_CONST_STRING 'Kept'
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49 CALL_FUNCTION n=1 nkw=0
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51 POP_TOP
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52 LOAD_NAME print
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54 LOAD_CONST_STRING 'Kept'
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56 CALL_FUNCTION n=1 nkw=0
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58 POP_TOP
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59 LOAD_NAME print
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61 LOAD_CONST_STRING 'Kept'
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63 CALL_FUNCTION n=1 nkw=0
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65 POP_TOP
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66 LOAD_NAME print
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68 LOAD_CONST_STRING 'Kept'
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70 CALL_FUNCTION n=1 nkw=0
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72 POP_TOP
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73 JUMP 77
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75 JUMP 66
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77 LOAD_CONST_OBJ \.\+='foo'
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79 STORE_NAME a
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81 LOAD_NAME a
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83 LOAD_CONST_OBJ \.\+='foo'
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85 BINARY_OP 2 __eq__
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86 POP_JUMP_IF_FALSE 95
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88 LOAD_NAME print
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90 LOAD_CONST_STRING 'Kept'
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92 CALL_FUNCTION n=1 nkw=0
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94 POP_TOP
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95 LOAD_CONST_OBJ \.\+='foo'
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97 STORE_NAME b
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99 LOAD_NAME b
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101 LOAD_CONST_OBJ \.\+='foo'
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103 BINARY_OP 2 __eq__
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104 POP_JUMP_IF_FALSE 113
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106 LOAD_NAME print
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108 LOAD_CONST_STRING 'Kept'
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110 CALL_FUNCTION n=1 nkw=0
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112 POP_TOP
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113 LOAD_CONST_OBJ \.\+='foo'
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115 LOAD_CONST_OBJ \.\+='foo'
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117 BINARY_OP 2 __eq__
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118 POP_JUMP_IF_FALSE 127
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120 LOAD_NAME print
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122 LOAD_CONST_STRING 'Kept'
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124 CALL_FUNCTION n=1 nkw=0
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126 POP_TOP
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127 LOAD_CONST_OBJ \.\+=()
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129 LOAD_CONST_OBJ \.\+='foo'
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131 BINARY_OP 2 __eq__
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132 POP_JUMP_IF_FALSE 141
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134 LOAD_NAME print
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136 LOAD_CONST_OBJ \.\+='Not Eliminated'
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138 CALL_FUNCTION n=1 nkw=0
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140 POP_TOP
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141 LOAD_CONST_FALSE
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142 LOAD_CONST_OBJ \.\+=False
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144 BINARY_OP 2 __eq__
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145 POP_JUMP_IF_FALSE 154
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147 LOAD_NAME print
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149 LOAD_CONST_STRING 'Kept'
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151 CALL_FUNCTION n=1 nkw=0
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153 POP_TOP
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154 JUMP 156
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156 LOAD_CONST_NONE
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157 RETURN_VALUE
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Kept
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Kept
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Kept
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Kept
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Kept
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Kept
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Kept
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Kept
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mem: total=\\d\+, current=\\d\+, peak=\\d\+
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stack: \\d\+ out of \\d\+
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GC: total: \\d\+, used: \\d\+, free: \\d\+
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No. of 1-blocks: \\d\+, 2-blocks: \\d\+, max blk sz: \\d\+, max free sz: \\d\+
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