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Reuse identifier of PREDICT macros as PREDICT_ID #17155

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Merged
merged 2 commits into from
Feb 21, 2020
Merged

Reuse identifier of PREDICT macros as PREDICT_ID #17155

merged 2 commits into from
Feb 21, 2020

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deiuch
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@deiuch deiuch commented Nov 14, 2019

Trivial change

In function _PyEval_EvalFrameDefault, macros PREDICT and PREDICTED use the same identifier creation scheme, which may be shared between them, reducing code repetition, and do ensure that the same identifier is generated.

@deiuch
Reuse identifier of PREDICT macros as PREDICT_ID
0d0103c 
In function `_PyEval_EvalFrameDefault`, macros PREDICT and PREDICTED use the same identifier creation scheme, which may be shared between them, reducing code repetition, and do ensure that the same identifier is generated.
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Thanks for your time @deiuch, and welcome to CPython!

@brandtbucher brandtbucher added skip news type-feature A feature request or enhancement labels Nov 14, 2019
brandtbucher
brandtbucher requested changes Nov 14, 2019
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I don't think we need a third macro. In your changes, PREDICTED and PREDICT_ID are aliases, right?

So why not just replace the two occurrences of PRED_##op in the definition of PREDICT with PREDICTED(op)?

@deiuch
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deiuch commented Nov 14, 2019

I don't think we need a third macro. In your changes, PREDICTED and PREDICT_ID are aliases, right?

So why not just replace the two occurrences of PRED_##op in the definition of PREDICT with PREDICTED(op)?

They are a bit different constructs. PREDICTED is a label statement, which is intended for use as a "landing pad" of goto's that address prediction of the given operator. There is a trailing colon character :)

brandtbucher
brandtbucher approved these changes Nov 14, 2019
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Ah, I missed the colon. This looks good, then!

taleinat
taleinat approved these changes Feb 21, 2020
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Indeed, looks good. I'll wait for input from someone with more experience with this C code though.

pitrou
pitrou approved these changes Feb 21, 2020
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+1, thank you.

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pitrou commented Feb 21, 2020

Opcode prediction is disabled on gcc / clang builds and enabled on MSVC, so both cases should be exercised by CI. Merging.

@pitrou pitrou merged commit baf29b2 into python:master Feb 21, 2020
@serhiy-storchaka
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It reduced readability of the code to me. I need now to search the definition of a new macro when I read definitions of PREDICT and PREDICTED, and it is not easy with my conditions.

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deiuch commented Feb 21, 2020

@serhiy-storchaka, you mean it is now harder to read with your IDE?

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I do not use IDE.

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Congrats on your first CPython contribution, @deiuch! 🍾

Looking forward to seeing more from you in the future.

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@taleinat taleinat taleinat approved these changes

@pitrou pitrou pitrou approved these changes

@brandtbucher brandtbucher brandtbucher approved these changes

@serhiy-storchaka serhiy-storchaka Awaiting requested review from serhiy-storchaka

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@deiuch @brandtbucher @pitrou @serhiy-storchaka @taleinat @the-knights-who-say-ni @bedevere-bot