[Python-checkins] peps: PEP 511: add list of AST optimizer issues

[victor.stinner]

https://hg.python.org/peps/rev/2eef070a4602
changeset:   6186:2eef070a4602
user:        Victor Stinner <victor.stinner at gmail.com>
date:        Fri Jan 15 02:14:44 2016 +0100
summary:
  PEP 511: add list of AST optimizer issues

files:
  pep-0511.txt |  35 ++++++++++++++++++++++++++++++-----
  1 files changed, 30 insertions(+), 5 deletions(-)


diff --git a/pep-0511.txt b/pep-0511.txt
--- a/pep-0511.txt
+++ b/pep-0511.txt
@@ -34,6 +34,8 @@
 ``importlib.abc.SourceLoader``. But code transformation is wider than just
 importing modules, see described use cases below.
 
+Writing an optimizer or a preprocessor is out of the scope of this PEP.
+
 Usage 1: AST optimizer
 ----------------------
 
@@ -58,18 +60,41 @@
 * `Dead code elimination
   <https://en.wikipedia.org/wiki/Dead_code_elimination>`_
 
-Using guards (see the PEP 510), it is possible to implement a much wider choice
-of optimizations. Examples:
+Using guards (see the `PEP 510
+<https://www.python.org/dev/peps/pep-0510/>`_), it is possible to
+implement a much wider choice of optimizations. Examples:
 
 * Simplify iterable: replace ``range(3)`` with ``(0, 1, 2)`` when used
   as iterable
 * `Loop unrolling <https://en.wikipedia.org/wiki/Loop_unrolling>`_
 * Call pure builtins: replace ``len("abc")`` with ``3``
 * Copy used builtin symbols to constants
+* See also `optimizations implemented in fatoptimizer
+  <https://fatoptimizer.readthedocs.org/en/latest/optimizations.html>`_,
+  a static optimizer for Python 3.6.
 
-See also `optimizations implemented in fatoptimizer
-<https://fatoptimizer.readthedocs.org/en/latest/optimizations.html>`_, a
-static optimizer for Python 3.6.
+The following issues can be implemented with an AST optimizer:
+
+* `Issue #1346238
+  <https://bugs.python.org/issue1346238>`_: A constant folding
+  optimization pass for the AST
+* `Issue #2181 <http://bugs.python.org/issue2181>`_:
+  optimize out local variables at end of function
+* `Issue #2499 <http://bugs.python.org/issue2499>`_:
+  Fold unary + and not on constants
+* `Issue #4264 <http://bugs.python.org/issue4264>`_:
+  Patch: optimize code to use LIST_APPEND instead of calling list.append
+* `Issue #7682 <http://bugs.python.org/issue7682>`_:
+  Optimisation of if with constant expression
+* `Issue #10399 <https://bugs.python.org/issue10399>`_: AST
+  Optimization: inlining of function calls
+* `Issue #11549 <http://bugs.python.org/issue11549>`_:
+  Build-out an AST optimizer, moving some functionality out of the
+  peephole optimizer
+* `Issue #17068 <http://bugs.python.org/issue17068>`_:
+  peephole optimization for constant strings
+* `Issue #17430 <http://bugs.python.org/issue17430>`_:
+  missed peephole optimization
 
 
 Usage 2: Preprocessor

-- 
Repository URL: https://hg.python.org/peps