On 11/28/2021 7:52 PM, Christopher Barker wrote:
I will frequently do simple computation with literals to make my code
more clear:
t = 2 * 3600 # 2 hours in seconds
That is optimized as you'd hope. Tested in 3.8:
>>> dis.dis("t = 2 * 3600")
1 0 LOAD_CONST 0 (7200)
2 STORE_NAME 0 (t)
4 LOAD_CONST 1 (None)
6 RETURN_VALUE
Eric
But I see no need to optimize this kind of thing -- it would never be
in a tight loop.
-CHB
On Sun, Nov 28, 2021 at 3:06 PM Rob Cliffe via Python-Dev
<python-dev@python.org> wrote:
I am slightly surprised that it seems to be *easier* to fold selected
constant expressions than to have more generic code to fold them all.
Or at least, all those that don't contain containers, such as
1 in [0,1,2]
Rob Cliffe
On 28/11/2021 21:10, Eric V. Smith wrote:
>> On Nov 28, 2021, at 3:03 PM, Serhiy Storchaka
<storch...@gmail.com> wrote:
>>
>> 28.11.21 17:13, Skip Montanaro пише:
>>>> That is not entirely true:
https://github.com/python/cpython/pull/29639#issuecomment-974146979
>>> The only places I've seen "if 0:" or "if False:" in live code
was for
>>> debugging. Optimizing that hardly seems necessary. In any
case, the
>>> original comment was about comparisons of two constants. I suppose
>>> sweeping up all of that into a constant expression
folding/elimination
>>> step performed on the AST and/or during peephole optimization
would
>>> cover both cases.
>> "if 0:" and "if False:" is already optimized by the compiler.
The OP
>> proposes to optimize "2 < 1", and I cannot imagine any use case
for this.
> I agree. I suggest we don’t add this optimization.
>
> Eric
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Christopher Barker, PhD (Chris)
Python Language Consulting
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