This patch by Antoine Pitrou optimizes the bytecode for conditional branches by
merging the following "POP_TOP" instruction into the conditional jump. For
example, the list comprehension "[x for x in l if not x]" produced the
following bytecode:
1 0 BUILD_LIST 0
3 LOAD_FAST 0 (.0)
>> 6 FOR_ITER 23 (to 32)
9 STORE_FAST 1 (x)
12 LOAD_FAST 1 (x)
15 JUMP_IF_TRUE 10 (to 28)
18 POP_TOP
19 LOAD_FAST 1 (x)
22 LIST_APPEND 2
25 JUMP_ABSOLUTE 6
>> 28 POP_TOP
29 JUMP_ABSOLUTE 6
>> 32 RETURN_VALUE
but after the patch it produces the following bytecode:
1 0 BUILD_LIST 0
3 LOAD_FAST 0 (.0)
>> 6 FOR_ITER 18 (to 27)
9 STORE_FAST 1 (x)
12 LOAD_FAST 1 (x)
15 POP_JUMP_IF_TRUE 6
18 LOAD_FAST 1 (x)
21 LIST_APPEND 2
24 JUMP_ABSOLUTE 6
>> 27 RETURN_VALUE
Notice that not only the code is shorter, but the conditional jump
(POP_JUMP_IF_TRUE) jumps right to the start of the loop instead of going through
the JUMP_ABSOLUTE at the end. "continue" statements are helped
similarly.
Furthermore, the old jump opcodes (JUMP_IF_FALSE, JUMP_IF_TRUE) have been
replaced by two new opcodes:
- JUMP_IF_TRUE_OR_POP, which jumps if true and pops otherwise
- JUMP_IF_FALSE_OR_POP, which jumps if false and pops otherwise
svn+ssh://pythondev@svn.python.org/python/trunk
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r69902 | tarek.ziade | 2009-02-23 13:41:29 +0100 (Mon, 23 Feb 2009) | 1 line
more test coverage
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r69878 | tarek.ziade | 2009-02-22 21:11:46 +0100 (Sun, 22 Feb 2009) | 1 line
removing map and lambda usage, so the test is similar to py3k's branch one
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svn+ssh://pythondev@svn.python.org/python/trunk
........
r69874 | tarek.ziade | 2009-02-22 20:58:12 +0100 (Sun, 22 Feb 2009) | 1 line
moved distutils.text_file tests into a real unittest class
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svn+ssh://pythondev@svn.python.org/python/trunk
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r69861 | tarek.ziade | 2009-02-22 01:07:45 +0100 (Sun, 22 Feb 2009) | 1 line
using versionchanged instead of versionadded for distutils doc on sdist default files
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+ Ditch using arguments to super().
+ Ditch subclassing from object directly.
+ Move directory check out of chaining path hook to file path hook/finder.
+ Rename some classes to better reflect they are finders, not importers.
svn+ssh://pythondev@svn.python.org/python/trunk
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r69806 | eric.smith | 2009-02-20 09:02:36 -0500 (Fri, 20 Feb 2009) | 1 line
Issue #5247: Improve error message when unknown format codes are used when using str.format() with str, int, and float arguments.
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r69268 | kristjan.jonsson | 2009-02-04 04:05:25 -0600 (Wed, 04 Feb 2009) | 1 line
issue 4804: Provide checks for the format string of strftime, and for the "mode" string of fopen on Windows. These strings are user provided from python and so we can avoid invoking the C runtime invalid parameter handler by first checking that they are valid.
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r69516 | hirokazu.yamamoto | 2009-02-10 22:13:06 -0600 (Tue, 10 Feb 2009) | 2 lines
Issue #5204: Define _PyVerify_fd on VC6 to make
test_fdopen (test_os.py) pass.
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r69757 | raymond.hettinger | 2009-02-18 23:34:35 -0600 (Wed, 18 Feb 2009) | 1 line
Add some cross-references to the docs. Simplify the python code equivalent for izip(). Supply an optional argument for the nth() recipe.
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r69761 | raymond.hettinger | 2009-02-18 23:51:41 -0600 (Wed, 18 Feb 2009) | 1 line
Add an example for math.fsum() and elaborate on the accurary note.
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r69765 | raymond.hettinger | 2009-02-19 00:55:03 -0600 (Thu, 19 Feb 2009) | 1 line
Add links to helpful external resources.
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r69770 | raymond.hettinger | 2009-02-19 03:50:24 -0600 (Thu, 19 Feb 2009) | 1 line
Inline coefficients in gamma(). Add reflection formula. Add comments.
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r69772 | vinay.sajip | 2009-02-19 06:31:32 -0600 (Thu, 19 Feb 2009) | 1 line
#5287: Add exception handling around findCaller() call to help out IronPython.
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r69777 | jeroen.ruigrok | 2009-02-19 12:52:21 -0600 (Thu, 19 Feb 2009) | 3 lines
Since we recommend one module per import line, reflect this also in the
documentation.
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r69795 | benjamin.peterson | 2009-02-19 21:31:23 -0600 (Thu, 19 Feb 2009) | 1 line
revert r69777 since all the experts agree that extra import lines distract from the code
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+ fixed an obvious merge glitch in a windows-only test.
Patch by Hirokazu Yamamoto.
I added a _PyVerify_fd() call to os.device_encoding() (new in python 3.0)
which also uses a raw file descriptor.
Mark Dickinson
Jeffrey Yasskin
Raymond Hettinger
Benjamin Peterson
Tarek Ziadé
Georg Brandl
Matthias Klose
Brett Cannon
Eric Smith
Amaury Forgeot d'Arc
Vinay Sajip
Martin v. Löwis