llvm dev - Sep 2018 - OptBisect implementation for new pass manager

On 9/26/2018 10:47 AM, Philip Pfaffe via llvm-dev wrote:
> Hi Fedor,
>
> can you make an example where a pass actually needs to opt-out? 
> Because IMO, bisect should quite literally to DebugCounter-style skip 
> every step in every ::run method's loop. Passes should not even be 
> concerned with this.
This isn't so much an issue for the optimization pipeline, but code 
generation involves some passes which are mandatory (e.g. isel).

-Eli

-- 
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux
Foundation Collaborative Project

Well, I think we don't have a clear idea about new-PM codegen should work
in general. Is this really something that concerns us right now?

Philip

On Wed, Sep 26, 2018 at 7:54 PM Friedman, Eli <efriedma at codeaurora.org>
wrote:
> On 9/26/2018 10:47 AM, Philip Pfaffe via llvm-dev wrote:
> > Hi Fedor,
> >
> > can you make an example where a pass actually needs to opt-out?
> > Because IMO, bisect should quite literally to DebugCounter-style skip
> > every step in every ::run method's loop. Passes should not even be
> > concerned with this.
>
> This isn't so much an issue for the optimization pipeline, but code
> generation involves some passes which are mandatory (e.g. isel).
>
> -Eli
>
> --
> Employee of Qualcomm Innovation Center, Inc.
> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux
> Foundation Collaborative Project
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20180926/2066feb8/attachment.html>

I'm concerned about codegen.  If Codegen is not yet ready for the new
PM, should the new PM really become default?  I would at least like to
see a plan of how Codegen is going to migrate before the new PM becomes
default.  Codegen pass pipelines have been wonky ever since I started
working with LLVM and it would be nice to get that cleaned up.

                            -David

Philip Pfaffe <philip.pfaffe at gmail.com> writes:
> Well, I think we don't have a clear idea about new-PM codegen should
> work in general. Is this really something that concerns us right now?
>
> Philip
>
> On Wed, Sep 26, 2018 at 7:54 PM Friedman, Eli
> <efriedma at codeaurora.org> wrote:
>
>     On 9/26/2018 10:47 AM, Philip Pfaffe via llvm-dev wrote:
>     > Hi Fedor,
>     >
>     > can you make an example where a pass actually needs to opt-out? 
>     > Because IMO, bisect should quite literally to DebugCounter-style
>     skip 
>     > every step in every ::run method's loop. Passes should not
even
>     be 
>     > concerned with this.
>     
>     This isn't so much an issue for the optimization pipeline, but
>     code 
>     generation involves some passes which are mandatory (e.g. isel).
>     
>     -Eli
>     
>     -- 
>     Employee of Qualcomm Innovation Center, Inc.
>     Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
>     a Linux Foundation Collaborative Project
>

On 09/26/2018 08:57 PM, Philip Pfaffe wrote:
> Well, I think we don't have a clear idea about new-PM codegen should 
> work in general. Is this really something that concerns us right now?
I dont believe it has anything to do specifically with New-PM.
It is just a property of getting a "real code".
There are passes that you cant skip if you want to get down to the 
runnable code.

regards,
   Fedor.
>
> Philip
>
> On Wed, Sep 26, 2018 at 7:54 PM Friedman, Eli <efriedma at
codeaurora.org
> <mailto:efriedma at codeaurora.org>> wrote:
>
>     On 9/26/2018 10:47 AM, Philip Pfaffe via llvm-dev wrote:
>     > Hi Fedor,
>     >
>     > can you make an example where a pass actually needs to opt-out?
>     > Because IMO, bisect should quite literally to DebugCounter-style
>     skip
>     > every step in every ::run method's loop. Passes should not
even be
>     > concerned with this.
>
>     This isn't so much an issue for the optimization pipeline, but code
>     generation involves some passes which are mandatory (e.g. isel).
>
>     -Eli
>
>     -- 
>     Employee of Qualcomm Innovation Center, Inc.
>     Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
>     a Linux Foundation Collaborative Project
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20180926/4ac97ef3/attachment.html>