Subject: Re: linux-next: build failure

From: Wenji Huang <[email-masked]>
Date: Tue, 29 Jul 2008 16:14:29 +0800

Ingo Molnar wrote:
> * Stephen Rothwell <[email-masked]> wrote:
> 
>> Hi Dave,
>>
>> Today's linux-next build (sparc64 defconfig) failed like this:
>>
>> kernel/time/tick-common.c: In function `tick_check_new_device':
>> kernel/time/tick-common.c:210: error: invalid lvalue in unary `&'
>> kernel/time/tick-common.c:223: error: invalid lvalue in unary `&'
>> kernel/time/tick-common.c:255: error: invalid lvalue in unary `&'
>>
>> gcc is version 3.4.5 sparc64 cross compiler (powercp64 host).
>>
>> The below patch fixes it.
>>
>> when you take the address of the result.  Noticed on a sparc64 compile
>> using a version 3.4.5 cross compiler.
>>
>> kernel/time/tick-common.c: In function `tick_check_new_device':
>> kernel/time/tick-common.c:210: error: invalid lvalue in unary `&'
>> kernel/time/tick-common.c:223: error: invalid lvalue in unary `&'
>> kernel/time/tick-common.c:255: error: invalid lvalue in unary `&'
>>
>> Signed-off-by: Stephen Rothwell <[email-masked]>
>> ---
>>  include/linux/cpumask.h |    2 +-
>>  1 files changed, 1 insertions(+), 1 deletions(-)
>>
>> diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
>> index 96d0509..d3219d7 100644
>> --- a/include/linux/cpumask.h
>> +++ b/include/linux/cpumask.h
>> @@ -287,7 +287,7 @@ static inline const cpumask_t *get_cpu_mask(unsigned int cpu)
>>   * gcc optimizes it out (it's a constant) and there's no huge stack
>>   * variable created:
>>   */
>> -#define cpumask_of_cpu(cpu) ({ *get_cpu_mask(cpu); })
>> +#define cpumask_of_cpu(cpu) (*get_cpu_mask(cpu))
> 
> hm, i'm wondering - is this a compiler bug?
> 
> 	Ingo

Same problem on x86/gcc 3.4.6, but will pass on gcc 4.x

Regards,
Wenji