[Cython] Bug in Cython producing incorrect C code

mark florisson markflorisson88 at gmail.com
Sun Feb 12 15:35:01 CET 2012

On 12 February 2012 14:06, Vitja Makarov <vitja.makarov at gmail.com> wrote:
> 2012/2/4 Vitja Makarov <vitja.makarov at gmail.com>:
>> 2012/1/26 mark florisson <markflorisson88 at gmail.com>:
>>> On 26 January 2012 19:27, Stefan Behnel <stefan_ml at behnel.de> wrote:
>>>> mark florisson, 26.01.2012 20:15:
>>>>> On 26 January 2012 18:53, Stefan Behnel wrote:
>>>>>> mark florisson, 26.01.2012 16:20:
>>>>>>> I think this problem can trivially be solved by creating a ProxyNode
>>>>>>> that should never be replaced by any transform, but it's argument may
>>>>>>> be replaced. So you wrap self.rhs in a ProxyNode and use that to
>>>>>>> create your CloneNodes.
>>>>>> I can't see what a ProxyNode would do that a CloneNode shouldn't do anyway.
>>>>> It wouldn't be a replacement, merely an addition (an extra indirection).
>>>> What I was trying to say was that a ProxyNode would always be required by a
>>>> CloneNode, but I don't see where a ProxyNode would be needed outside of a
>>>> CloneNode. So it seems rather redundant and I don't know if we need a
>>>> separate node for it.
>>> Yes it would be needed only for that, but I think the only real
>>> alternative is to not use CloneNode at all, i.e. make the
>>> transformation Dag mentioned, where you create new rhs (NameNode?)
>>> references to the temporary result.
>> Now it seems to be the only case when we got problem like this. It
>> means that clones may be safely created at very late stage.
>> So transforming CascadeAssignment into SingleAssignments doesn't solve
>> generic problem.
>> I tried to implement conditional inlining the same problem may happen
>> there (ConditionalCallNode owns arguments and replaces
>> SimpleCallNode's args with clones). Splitting analyse_expressions()
>> would help. On the other hand moving this optimization after
>> OptimizeBuiltinCalls() would help too.
> I tried to introduce finalize_expressions() here:
> https://github.com/vitek/cython/tree/_finalize_expressions
> I moved arg_tuple creation logic from SimpleCallNode's analyse_types()
> to finalize_expressions() so few tests are broken now.
> Now inlining is done right before AnalyseExpressions before arg_tuple
> is created (before pyobject coercion nodes are created). It must be
> run after expression analysis. So I'm completely sure that
> analyse_types() must be split.

Ah, I didn't realize you were working on that, I fixed the cascaded
assignment bug and pushed it to master a while ago. Anyway, if this
fixes the problem for cascaded assignment, feel free to do a hard
reset to remove those commits (probably want to keep the added tests

> --
> vitja.
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