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Re: Question about find modifiable mems
- From: shmeel gutl <shmeelgutl at shmuelhome dot mine dot nu>
- To: GCC Development <gcc at gcc dot gnu dot org>
- Date: Mon, 1 Aug 2016 00:03:29 +0300
- Subject: Re: Question about find modifiable mems
- Authentication-results: sourceware.org; auth=none
- References: <556EA138.4050109@shmuelhome.mine.nu>
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