Re: [PATCH] misplaced parenthesis?

[Randolph Chung <randolph@tausq.org>]

The wrong version of course produces different code....

the original and the corrected one may produce different code depending 
on how the compiler schedules things.

randolph

Matt Turner wrote:
> Does gcc produce different code for the three variations?
>
> Matt
>
> On Sat, May 16, 2009 at 12:14 AM, Randolph Chung <randolph@tausq.org> wrote:
>   
>> This is a bit confusingly written, but your patch does not appear to be
>> correct.
>>
>> == has higher precedence than &, so you are basically changing it to:
>> if (likely(t1 & 1))
>>
>> it really should be
>>
>> -       if (likely(t1 & (sizeof(unsigned int)-1)) == 0) {
>> +       if (likely((t1 & (sizeof(unsigned int)-1)) == 0)) {
>>
>> randolph
>>
>>
>> Roel Kluin wrote:
>>     
>>> Fix misplaced parenthesis.
>>>
>>> Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
>>> ---
>>> I think this is what was intended? Note that this patch may affect
>>> profiling.
>>>
>>> diff --git a/arch/parisc/lib/memcpy.c b/arch/parisc/lib/memcpy.c
>>> index bbda909..30207b0 100644
>>> --- a/arch/parisc/lib/memcpy.c
>>> +++ b/arch/parisc/lib/memcpy.c
>>> @@ -405,7 +405,7 @@ byte_copy:
>>>   unaligned_copy:
>>>        /* possibly we are aligned on a word, but not on a double... */
>>> -       if (likely(t1 & (sizeof(unsigned int)-1)) == 0) {
>>> +       if (likely(t1 & (sizeof(unsigned int)-1) == 0)) {
>>>                t2 = src & (sizeof(unsigned int) - 1);
>>>                  if (unlikely(t2 != 0)) {
>>> --
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>>>       
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>>     
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