[LLVMdev] "grep -w" irregularity

[Daniel Berlin]

Also, it only happens with the locale set to en_US.UTF-8 (default on
ubuntu 8.04), but it's still a bug even in a utf-8 locale since both
shlh's are followed immediately by i, which are not "non-word
constituent characters".



On Tue, Dec 30, 2008 at 10:38 PM, Daniel Berlin <dberlin at dberlin.org> wrote:
> I've attached the .s file it produces in case you want to file a bug
> against grep.
>
> On Tue, Dec 30, 2008 at 10:36 PM, Daniel Berlin <dberlin at dberlin.org> wrote:
>> On Tue, Dec 30, 2008 at 8:59 PM, Scott Michel <scottm at aero.org> wrote:
>>> 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.)
>>
>> The buildbot is running 8.04 of ubuntu.
>> This actually does appear to be a bug in grep.
>>
>> The grep -w command on the buildbot produces the following output:
>>
>>        shlh    $3, $3, $4
>>        shlh    $3, $4, $3
>>        shlh    $3, $3, $4
>>        shlh    $3, $4, $3
>>        shlh    $3, $3, $4
>>        shlh    $3, $4, $3
>>        shlh    $3, $4, $3
>>        shlh    $3, $4, $3
>>        .size   shlhi_i16_7,.-shlhi_i16_7
>>        shlh    $3, $4, $3
>>
>> man grep says the following for -w:
>>
>>  -w, --word-regexp
>>              Select  only  those  lines  containing  matches  that form whole
>>              words.  The test is that the matching substring must  either  be
>>              at  the  beginning  of  the  line,  or  preceded  by  a non-word
>>              constituent character.  Similarly, it must be either at the  end
>>              of  the  line  or  followed by a non-word constituent character.
>>              Word-constituent  characters  are  letters,  digits,   and   the
>>              underscore.
>>
>>
>> Clearly, it does not match the ending criteria since neither of the
>> matches on the .size line are followed by non-word constituent
>> characters or eol.
>>
>