[llvm-dev] Wrong code bug after GVN/PRE?

[Philip Reames via llvm-dev]

Will try to get to this by end of week.  Feel free to ping me if I don't 
respond by then.

Philip


On 01/22/2017 11:54 PM, Mikael Holmén wrote:
> Hi Philip,
>
> On 01/21/2017 01:03 AM, Friedman, Eli wrote:
>> On 1/20/2017 3:19 PM, Philip Reames via llvm-dev wrote:
>>>
>>> If someone can produce an *IR* reproducer which they believe is
>>> incorrect, I'm happy to take a look at the PRE code.  I will not have
>>> the time to reproduce this from C or work through the interaction of
>>> other passes;  I will only look at this if there is a bug with PRE
>>> specific IR reproducer attached.
>>>
>>
>> https://llvm.org/bugs/show_bug.cgi?id=31651 has an IR testcase.
>
> As Eli said, in the PR there is IR that I think is miscompiled if you 
> run gvn on it.
>
> In the PR and earlier in this thread I pasted some C-like code just to 
> describe what I think is happening since I thought it was easier than 
> pasting llvm assembler, but the pre_gvn.ll file in PR31651 can indeed 
> be used to reproduce the problem by just running gvn on it.
>
> Great if you could have a look!
> Mikael
>
>>
>> -Eli
>>