Here's an updated patch:
Reported-by: Roel Kluin <roel.kluin@xxxxxxxxx>
Signed-off-by: Randolph Chung <tausq@xxxxxxxxxxxxxxxx>
diff --git a/arch/parisc/lib/memcpy.c b/arch/parisc/lib/memcpy.c
index 2d68431..827e535 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)) {
On Mon, May 18, 2009 at 9:42 AM, Randolph Chung<randolph@xxxxxxxxx> wrote:
> 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@xxxxxxxxx>
>> 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@xxxxxxxxx>
>>>> ---
>>>> 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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>
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