[LLVMdev] "grep -w" irregularity

[Scott Michel]

On Dec 30, 2008, at 5:47 PM, Chris Lattner wrote:
>
> On Dec 30, 2008, at 5:24 PM, Scott Michel wrote:
>
>> Chris:
>>
>> On my _local_ x86_64 Ubuntu 7.10 machine, the shift_ops.ll is an
>> unexpected success (i.e., "grep -w shlh %t1.s | count 9" succeeds.)
>>
>> I get the same unexpected success on my x86_64 Mac 10.4.11.
>>
>> On the x86_64 buildbot, the same test fails. The culprit is grep,
>> evidently. It's just that simple.
>
> Not necessarily.  That builder could be getting a different .s file
> from LLC.

Given that I have an x86_64 machine here and the buildbot is x86_64,  
and given that my local x86_64 machine "unexpectedly" succeeds, I'm  
less inclined to suspect LLC at this point.

Granted, I'm probably not running the same Linux distribution that  
the buildbot is running. But still, my local Linux x86_64 box  
succeeds where the buildbot fails, using the same svn version (i.e.,  
no diffs between the LLVM repo and my local copy.)

>> LLC is still run.  If there is a bug in the code generator, it could
> easily manifest itself this way.  32/64-bit portability issues, buffer
> overruns and other undefined behavior could easily cause this sort of
> thing.  Please ask the owner of that builder nicely to send you the .s
> file that it is producing.  If it is identical to the one you get then
> I'll believe it is a grep difference, but that doesn't sound like the
> most likely issue.

I'd be completely shocked if llc were _not_ run, since the test  
invokes it. I'll contact the buildbot owner -- maybe it's something  
funky between Linux distributions (oh, now there's a total surprise!)


-scooter