[LLVMdev] list of LLVM optimization passes

Manuel Llosa
Tue, 06 Jul 2010 15:04:14 -0000

Dear Kenneth, I see. Do you plan sharing your framework in open source?
For now, I will continue using ctuning tools (they support LLVM as is but not
some specific things on JIT dynamic recompilation what is my thesis about).
I will like to compare all tools of course and will be happy
to share results although real not until autumn).Look forward
to your results and hopefully keep in touch.
Regards!

Manuel

-----Original Message-----
From: llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-bounces at cs.uiuc.edu] On
Behalf Of Kenneth Hoste
Sent: Tuesday, July 06, 2010 4:50 PM
To: Manuel Llosa
Cc: llvmdev at cs.uiuc.edu
Subject: Re: [LLVMdev] list of LLVM optimization passes


On Jul 6, 2010, at 10:09 AM, Manuel Llosa wrote:

> Dear Kenneth, May I ask you if you are implementing your search within
> ctuning framework: ctuning.org/ctuning-cc?

No, I'm not. I've built my own framework, and since I don't have any
experience with the
ctuning framework, I don't intend to start using that. There's little
gain in it for me.

> The thing is that I use it since some time for my thesis to optimize code
size and
> compilation time and run time with GCC though they are not using genetic
algorithms
> but some slower hybrid of random exploration and than AI with some fronteer
detection.
> Since recent version can be working with other compilers then GCC and has
some support for LLVM
> so I have thought to improve this support and compare both GCC and LLVM.
But if you are extending that
> tool now, I do not want to duplicative work so could you tell me please for
how long it can take because I
> can wait for your extensions. I want to compare this multi-objective modes
for GCC 4.5 and LLVM 2.7
> for many flags and will want to put experiments in their database for
everyone to see if it is works ...

Since it doesn't support LLVM as is, that motivates me even more to stick
with my own framework.

Good luck with your experiments, I'd love to see some results when you have
them.

greetings,

Kenneth

> Regards!
>
> Manuel
>
>
>
>
> -----Original Message-----
> From: llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-bounces at
cs.uiuc.edu] On Behalf Of Kenneth Hoste
> Sent: Sunday, July 04, 2010 4:19 PM
> To: llvmdev at cs.uiuc.edu
> Subject: [LLVMdev] list of LLVM optimization passes
>
> Hello LLVMers,
>
> I'm putting together some (extensive) experiments with using a genetic
algorithm to construct sets of optimization
> passes that are as close as optimal in a number of ways, e.g. compilation
time, execution time, code size, ...
>
> I've figured out which LLVM tools I should use for this (llvm-gcc to
obtain bitcode, opt to optimize, llc to obtain assembly, ...),
> and I'm now looking into which optimization passes I should take into
account in my experiments.
>
> First, one thing that is not entirely clear to me: do analysis passes
result in additional information being made available
> to other passes, e.g. does "-domtree" enable more aggressive
optimization being done by other passes?
> In other words, should I consider some analysis passes in my setup, and if
so, which ones?
>
> Initially, I just used the set of 58 'transform' passes listed at
[1].
> Unfortunately, it turns out that this list if not up to date. Below are my
findings, comparing [1] to "opt -help".
>
> If someone can clarify the points below, I'll try and put together a
patch for [1], resolving the inconsistencies...
>
> Several transform passes listed at [1] are no longer supported by the opt
tool:
>
> 	-indmemrem
> 	-insert-block-profiling
> 	-insert-function-profiling
> 	-insert-null-profiling-rs
> 	-insert-rs-profiling-framework
> 	-lowerallocs
>
> Is assume this is known? Were these passes removed recently?
>
>
> A large number of passes mentioned in "opt -help" are not
mentioned in [1]:
>
> 	-abcd
> 	-always-inline
> 	-functionattrs
> 	-insert-optimal-edge-profiling
> 	-instnamer
> 	-iv-users
> 	-lazy-value-info
> 	-lda
> 	-libcall-aa
> 	-live-values
> 	-mergefunc
> 	-partial-inliner
> 	-partialspecialization
> 	-pointertracking
> 	-print-dbginfo
> 	-print-dom-info
> 	-profile-estimator
> 	-profile-verifier
> 	-sccvn
> 	-scev-aa
> 	-simplify-libcalls-halfpowr
> 	-split-geps
> 	-ssi
> 	-ssi-everything
> 	-strip-debug-declare
> 	-strip-nondebug
>
> It's unclear to me which of these passes are transform passes, and
which ones are analysis passes.
> If someone here can point out the transform and analysis passes for me, I
can try and come up with a
> patch for [1].
>
> greetings,
>
> Kenneth
>
>
> [1] http://llvm.org/docs/Passes.html
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