Question about find modifiable mems

[shmeel gutl]

On 03-Jun-15 09:39 AM, shmeel gutl wrote:
> find_modifiable_mems was introduced to gcc 4.8 in september 2012. Is 
> there any documentation as to how it is supposed to help the haifa 
> scheduler?
>
> In my private port of gcc it make the following type of transformations
>
>     from
>         a= *(b+20)
>         b+=30
>
>     to
>         b+=30
>         a=*(b-10)
>
> Although this is functionally correct, it has changed an ANTI_DEP into 
> a TRUE_DEP and thus introduced stalls. If it went the other way, that 
> would be good. Any pointers?
>
> Thanks,
> Shmeel

It seems that the problem comes from the change from ANTI_DEP to 
TRUE_DEP. The flow graph needs to be updated to reflect this change. Can 
someone look into this?

Shmeel