Empty loop elimination in 4.0 ?

[Andrew Pinski]

On Jan 11, 2005, at 2:13 PM, Luca Benini wrote:

>> This:
>> int *f;
>> int i;
>> for (i=0;i<10;i++)
>>  f[i] = 0;
>>
>> will be converted to:
>>
>> memset (f, 0, i * sizeof(*f));
>> for (i=0;i<10;i++)
>>  ;
> ....but
>
> for (i=0;i<10;i++)
>   f[i] = x;
>
> can't be converted in
>
> memset (f, x, i * sizeof(*f));
>
> for every x.

Yes I know that :)
We can convert it if the sizeof(*f) is 1 or if f is a pattern
which can converted for use with memset.  The reason why I said 0 is
because that is the most common place where people should/could be using
memset.

-- Pinski