Andrew Haley wrote:
> eCos@ wrote:
>> ===============================================
>> int *p;
>>
>> int main(void)
>> {
>> p++;
>> __asm__ __volatile__ (""::);
>> p++;
>> }
>> ===============================================
>> assembly code is like:
>> 'addl $4, %eax'
>> 'addl $4, %eax'
>> ===============================================
>> int *p;
>>
>> int main(void)
>> {
>> p++;
>> __asm__ __volatile__ (""::);
>> p+=8;
>> }
>> ===============================================
>> According to the assembly code, we found that gcc merge the 'p++' & 'p+=8'
>> and generate 'addl $36, p'
> If you really need a memory barrier, you have to use one:
So, this is a real bug then - but it's a missed optimisation in the first
case, not a bogus one in the second case?
cheers,
DaveK
