llvm dev - Aug 2008 - [LLVMdev] ComputeMaskedBits Bug

On Saturday 19 July 2008 23:53, Nick Lewycky wrote:
> > That said, there are many places that don't respect the Mask. 
Closer
> > reading of the comment leads me to believe the Mask is simply a
> > time-saving device, not a correctness-enforcing mechanism.
>
> That's fine, but if you fix it that way, please audit
> InstructionCombiner SimplifyDemandedBits, which I believe has the same bug.
Ok.
> > I've fixed the PHI analysis to do the min in our code and it fixes
the
> > testcase I was working on.  Doing a min like this would also allow us
> > to have PHI nodes compute known zero and one bits even when there
> > isn't a recurrence.
>
> Great! Did you commit a patch for this?
Not yet.  :(  I am waiting for some paperwork on this end.  Hopefully we only 
have to go through this pain once and then I can be much more active.  I've
been told it should be approved by the end of the month.

                                                       -Dave

Sorry for being out of touch. Has this been fixed?

Evan

On Jul 21, 2008, at 1:09 PM, David Greene wrote:
> On Saturday 19 July 2008 23:53, Nick Lewycky wrote:
>
>>> That said, there are many places that don't respect the Mask.
>>> Closer
>>> reading of the comment leads me to believe the Mask is simply a
>>> time-saving device, not a correctness-enforcing mechanism.
>>
>> That's fine, but if you fix it that way, please audit
>> InstructionCombiner SimplifyDemandedBits, which I believe has the  
>> same bug.
>
> Ok.
>
>>> I've fixed the PHI analysis to do the min in our code and it
fixes
>>> the
>>> testcase I was working on.  Doing a min like this would also allow
>>> us
>>> to have PHI nodes compute known zero and one bits even when there
>>> isn't a recurrence.
>>
>> Great! Did you commit a patch for this?
>
> Not yet.  :(  I am waiting for some paperwork on this end.   
> Hopefully we only
> have to go through this pain once and then I can be much more  
> active.  I've
> been told it should be approved by the end of the month.
>
>                                                       -Dave
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> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev

On Wednesday 20 August 2008 18:08, Evan Cheng wrote:
> Sorry for being out of touch. Has this been fixed?
I've been trying to test it but have had problems due to the llvm-gcc
bootstrap problems I mentioned last week.

It's had lots of testing over here so I'll just check it in today.

                                              -Dave