llvm dev - Jul 2020 - [RFC] Introducing classes for the codegen driven by new pass manager

Hi Matt, which analysis is this?
________________________________________
From: Matt Arsenault <whatmannerofburgeristhis at gmail.com> on behalf of
Matt Arsenault <arsenm2 at gmail.com>
Sent: Tuesday, July 21, 2020 12:02 PM
To: Craig Topper
Cc: Chen, Yuanfang; Nicolai Hähnle; llvm-dev at lists.llvm.org
Subject: Re: [llvm-dev] [RFC] Introducing classes for the codegen driven by new
pass manager


> On Jul 21, 2020, at 14:53, Craig Topper <craig.topper at gmail.com>
wrote:
>
> One thing I want to mention. I believe in the current legacy pass manager
implementation only one MachineFunction ever exists at a time. It is deleted
before the next MachineFunction is created. This is very important for memory
usage. I think the MachineOutliner being in the pipeline may create an exception
to this. I think the initial version of retpoline used a ModulePass and that had
to be changed to avoid excessive memory usage.
>
> ~Craig
An addition to this is analyses between different MachineFunctions still matter.
AMDGPU forces SCC order and has an analysis to track function information after
it’s been codegened. This is needed to track the cumulative register usage of
kernels

-Matt

> On Jul 22, 2020, at 14:12, Chen, Yuanfang <Yuanfang.Chen at sony.com>
wrote:
> 
> Hi Matt, which analysis is this?
> 
I checked again, and it currently is not a real analysis. It’s just a
CallGraphResourceInfo map in AMDGPUAsmPrinter, which happens to rely on
CodeGenSCCOrder. I think I intended to move this to a separate analysis at one
point

-Matt

Thanks. I'll take a look.

________________________________________
From: Matt Arsenault <whatmannerofburgeristhis at gmail.com> on behalf of
Matt Arsenault <arsenm2 at gmail.com>
Sent: Wednesday, July 22, 2020 11:19 AM
To: Chen, Yuanfang
Cc: Craig Topper; Nicolai Hähnle; llvm-dev at lists.llvm.org
Subject: Re: [llvm-dev] [RFC] Introducing classes for the codegen driven by new
pass manager


> On Jul 22, 2020, at 14:12, Chen, Yuanfang <Yuanfang.Chen at sony.com>
wrote:
>
> Hi Matt, which analysis is this?
>
I checked again, and it currently is not a real analysis. It’s just a
CallGraphResourceInfo map in AMDGPUAsmPrinter, which happens to rely on
CodeGenSCCOrder. I think I intended to move this to a separate analysis at one
point

-Matt