llvm dev - Sep 2014 - [LLVMdev] loop clone?

Hi,

     I want to add a branch before a loop, and clone the loop to the 
else part. After that, I can do instrumentation in one loop, and keep 
the other one uninstrumented. Does llvm have existing functionality to 
clone loops, or similar codes I can check?

     Thanks a lot!

     Best,

Linhai

Hi Linhai,

I'm not aware of a function to clone a loop but you can extract the loop
into its own function [1] and clone the function [2]. In the end you
just need a conditional to decide which function to call.

I hope this helps,
  Johannes

[1]
http://llvm.org/docs/doxygen/html/classllvm_1_1CodeExtractor.html#a52e4200738c1e0cb57d15647de3125a0
[2]
http://llvm.org/docs/doxygen/html/namespacellvm.html#a5596246c2350cb74f31ffa7695d5923c

On 09/24, Linhai wrote:
> Hi,
> 
>     I want to add a branch before a loop, and clone the loop to the else
> part. After that, I can do instrumentation in one loop, and keep the other
> one uninstrumented. Does llvm have existing functionality to clone loops,
or
> similar codes I can check?
> 
>     Thanks a lot!
> 
>     Best,
> 
> Linhai
> _______________________________________________
> 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
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Hi Linhai,

The similar transformation is done in LoopUnswitch.cpp [1] and it has a static
CloneLoop [2] function too.

[1]  http://llvm.org/docs/doxygen/html/LoopUnswitch_8cpp_source.html 
[2]  http://llvm.org/docs/doxygen/html/LoopUnswitch_8cpp_source.html#l00668


Vinay.

-----Original Message-----
From: llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-bounces at cs.uiuc.edu] On
Behalf Of Linhai
Sent: Thursday, September 25, 2014 2:39 AM
To: LLVM Developers Mailing List
Subject: [LLVMdev] loop clone?

Hi,

     I want to add a branch before a loop, and clone the loop to the else part.
After that, I can do instrumentation in one loop, and keep the other one
uninstrumented. Does llvm have existing functionality to clone loops, or similar
codes I can check?

     Thanks a lot!

     Best,

Linhai
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