[llvm] r295378 - [LSR] Prevent formula with SCEVAddRecExpr type of Reg from Sibling loops

[Wei Mi via llvm-commits]

On Wed, Feb 22, 2017 at 4:08 PM, Wei Mi <wmi at google.com> wrote:

>
>
> On Wed, Feb 22, 2017 at 3:46 PM, Davide Italiano <davide at freebsd.org>
> wrote:
>
>> On Thu, Feb 16, 2017 at 1:27 PM, Wei Mi via llvm-commits
>> <llvm-commits at lists.llvm.org> wrote:
>> > Author: wmi
>> > Date: Thu Feb 16 15:27:31 2017
>> > New Revision: 295378
>> >
>> > URL: http://llvm.org/viewvc/llvm-project?rev=295378&view=rev
>> > Log:
>> > [LSR] Prevent formula with SCEVAddRecExpr type of Reg from Sibling loops
>> >
>>
>> Sorry if I'm late, but our downstream branch was a little bit behind.
>> With this test LTO time of some of our internal codebases skyrockets.
>> running `llc` on the test attached takes ~7 seconds with the change
>> reverted and I had to kill it after 10 minutes with the change in. Can
>> you please take a look, and see if you can fix this easily (or
>> revert?) I'd like to get our bots green again.
>>
>>
> Sorry to break your bot. I can reproduce the problem and am looking at it.
> Thanks for the testcase.
>
> Wei.
>

Hi Davide,

I found the problem was there for a long time (I reproduce the same problem
since r290782. I cannot try earlier versions because they cannot digest the
IR). rL294814 just hided the problem and rL295378 exposed the problem
again.

Is this the first time you see the problem? I am curious why it doesn't
break the bot before.

Thanks,
Wei.


>
>
>>
>> --
>> Davide
>>
>> "There are no solved problems; there are only problems that are more
>> or less solved" -- Henri Poincare
>>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20170222/e28e2944/attachment.html>