For those of you attending the upcoming Developers' Meeting, I'll be running a Birds-of-a-Feather about code size optimization. It'll be on Oct. 6 at 9:30am PDT, immediately after Aditya Kumar's tech talk on the same subject.
There are several topics I think we could potentially discuss:
(1) Situations where people have needed to optimize code size.
(2) Situations where other compilers currently optimize code size better than LLVM.
(3) A survey of academic and experimental techniques for reducing code size, including our own, ranging from outlining to program specialization.
(4) Which techniques and improvements would be most beneficial to add to LLVM?
But that's a lot to cover, and I want to make sure we spend our time on the areas people are most interested in. What would you most like to have a discussion about?
From: llvm-dev <llvm-dev-bounces@lists.llvm.org> On Behalf Of Sean Bartell
via llvm-dev
Sent: Sunday, September 27, 2020 2:14 PM
To: llvm-dev <llvm-dev@lists.llvm.org>
Cc: aditya kumar <hiraditya@gmail.com>; Vikram Adve <vadve@illinois.edu>
Subject: [llvm-dev] Code size BoF @ Developers' Meeting
Hi all,
For those of you attending the upcoming Developers' Meeting, I'll be
running a Birds-of-a-Feather about code size optimization. It'll be on
Oct. 6 at 9:30am PDT, immediately after Aditya Kumar's tech talk on the
same subject.
There are several topics I think we could potentially discuss:
(1) Situations where people have needed to optimize code size.
There's been some interest lately in doing less optimization on cold code;
see for example ⚙ D87337 [PGO] De-Optimizing cold functions based on PGO info (PATCH 1/2) which slaps 'optnone' on
cold functions. But it might be better to optimize cold code for size.
That's maybe not so easy with LLVM's one-pipeline-for-all design.
--paulr