[issue32616] Significant performance problems with Python 2.7 built with clang 3.x or 4.x

[Zhiming Wang]

Zhiming Wang <zmwangx at gmail.com> added the comment:

Turns out python 2.7.10 doesn't suffer from the performance issue even when compiled with stock clang 4.x, and upon further investigation, I tracked down the commit that introduced the regression:

    commit 2c992a0788536087bfd78da8f2c62b30a461d7e2
    Author: Benjamin Peterson <benjamin at python.org>
    Date:   Thu May 28 12:45:31 2015 -0500
    
        backport computed gotos (#4753)

So Naoki was right that computed gotos is (solely) to blame here.

----------

_______________________________________
Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue32616>
_______________________________________