[llvm-dev] General question about enabling partial inlining

[Xinliang David Li via llvm-dev]

On Tue, Oct 3, 2017 at 9:21 AM, Jun Lim via llvm-dev <
llvm-dev at lists.llvm.org> wrote:

> Hi Graham,
>
>
>
> Thanks for sharing this.  Are you planning on enabling the pass only on
> PGO? Even in non-PGO, I noticed some performance gains when we are
> aggressive in partially inlining the early return part, especially when the
> callee spill CSRs in the entry block. At a high level, I have two
> questions:
>
>    1. What is the main obstacle that prevent the pass from being enabled
>    by default?
>    2. Would it make sense to give some bonus in the cost model when we
>    detect the possibility of spilling CSRs in the entry block?
>
> More enhanced shrink-wrapping will probably take care of this, so using
partial inlining to do that seems like a wrong motivation :)

David



>
>    1.
>
>
>
> Thanks,
>
> Jun
>
> *From:* Graham Yiu [mailto:gyiu at ca.ibm.com]
> *Sent:* Tuesday, October 3, 2017 11:08 AM
> *To:* junbuml at codeaurora.org
> *Cc:* llvm-dev at lists.llvm.org
> *Subject:* Re: [llvm-dev] General question about enabling partial inlining
>
>
>
> Hi Jun,
>
> We're actually looking at enhancing the partial inlining pass right now
> (see http://lists.llvm.org/pipermail/llvm-dev/2017-August/116515.html)
>
> We'd be interested in turning on the pass by default some time in the
> future, if our enhancements prove beneficial.
>
> Cheers,
>
> Graham Yiu
> LLVM Compiler Development
> IBM Toronto Software Lab
> Office: (905) 413-4077 C2-707/8200/Markham
> Email: gyiu at ca.ibm.com
>
> [image: Inactive hide details for via llvm-dev ---09/13/2017 01:12:02
> PM---Hi, I noticed some performance gains in some spec benchmarks]via
> llvm-dev ---09/13/2017 01:12:02 PM---Hi, I noticed some performance gains
> in some spec benchmarks without
>
> From: via llvm-dev <llvm-dev at lists.llvm.org>
> To: llvm-dev at lists.llvm.org
> Date: 09/13/2017 01:12 PM
> Subject: [llvm-dev] General question about enabling partial inlining
> Sent by: "llvm-dev" <llvm-dev-bounces at lists.llvm.org>
> ------------------------------
>
>
>
>
> Hi,
>
> I noticed some performance gains in some spec benchmarks without
> significant code size bloat when aggressively performing partial
> inlining, especially when the original callee spill CSRs in the entry
> block. I guess the partial inlining is not enabled mainly due to the
> code size. Is there any other issue which prevent the pass from being
> enabled? Do we have any plan or any on-going works to enable partial
> inlining ?
> Thanks,
> Jun
>
> --
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