[LLVMdev] noalias and alias.scope metadata producers

[Johannes Doerfert]

Hey Samuel,

I'm not sure if this is interesting for you but maybe it is:

Polly can emit these metadata for loop nests we can analyze. It is based
on runtime alias checks, thus versioning. We are currently fixing the bugs
in the runtime alias check generation we merged yesterday but after that
(or if you like earlier) I can submit the annotation patch for review.
Some limited tests on polybench benchmarks (e.g., 3mm) without any polyhedral
optimizations, thus only parallel and noalias annotations, showed up to
20% improvement.

Best regards,
  Johannes

On 09/19, Samuel F Antao wrote:
> 
> 
> Hi all,
> 
> In LLVM language reference I read that one can use noalias and alias.scope
> metadata to provide more detailed information about pointer aliasing.
> However, I was unable to obtain any LLVM IR annotations using this metadata
> from any LLVM optimization pass or Clang frontend (am I missing
> something?).
> 
> If I understand it correctly, this information would complement the
> type-based alias information and whatever mechanisms the alias analysis
> passes in LLVM compute from the input program. I was wondering if the
> coverage provided by these two components is already acceptable or if there
> is work that can be done in LLVM IR clients like clang to provide more
> information with proper noalias and alias.scope annotations.
> 
> Any comments?
> 
> Thanks!
> Samuel

> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev


-- 

Johannes Doerfert
Researcher / PhD Student

Compiler Design Lab (Prof. Hack)
Saarland University, Computer Science
Building E1.3, Room 4.26

Tel. +49 (0)681 302-57521 : doerfert at cs.uni-saarland.de
Fax. +49 (0)681 302-3065  : http://www.cdl.uni-saarland.de/people/doerfert
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 213 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20140920/b09f1cf8/attachment.sig>