llvm dev - May 2010 - [LLVMdev] Finding Merge nodes in CFG (ambika@cse.iitb.ac.in)

hi ambika,
I am not sure about this solution as i just started working in this field.
How about taking analogy of a problem which ask us to find nearest common
parent of two nodes in a tree.
Let me know if I can be corrected.

- Anubhav
intern IIT M
B. Tech 4th year CSE
VIT University, Vellore.


On 31 May 2010 22:30, <llvmdev-request at cs.uiuc.edu> wrote:
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> Today's Topics:
>
>   1. Re: How difficult is to fix this error: JIT does not support
>      address-of-label yet! [patch submitted] (Yuri)
>   2. Finding Merge nodes in CFG (ambika)
>   3. Re: How difficult is to fix this error: JIT does not      support
>      address-of-label yet! [patch submitted] (Eric Christopher)
>   4. Re: LLVM opportunities with Google Native Client (Fabio Kaminski)
>   5. Re: Finding Merge nodes in CFG (John Criswell)
>   6. libllvm on windows (John Lask)
>   7. Re: libllvm on windows (T?r?k Edwin)
>   8. Re: Finding Merge nodes in CFG (ambika at cse.iitb.ac.in)
>   9. Error with instruction selection (Kalle.Raiskila at nokia.com)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sun, 30 May 2010 13:32:22 -0700
> From: Yuri <yuri at rawbw.com>
> Subject: Re: [LLVMdev] How difficult is to fix this error: JIT does
>        not support address-of-label yet! [patch submitted]
> To: llvmdev at cs.uiuc.edu
> Message-ID: <4C02CB56.8000105 at rawbw.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> I just implemented this feature and here is the patch:
> http://llvm.org/bugs/show_bug.cgi?id=7264
>
> Yuri
>
>
> ------------------------------
>
> Message: 2
> Date: Mon, 31 May 2010 03:19:42 +0530
> From: ambika <ambika at cse.iitb.ac.in>
> Subject: [LLVMdev] Finding Merge nodes in CFG
> To: "llvmdev at cs.uiuc.edu" <llvmdev at cs.uiuc.edu>
> Message-ID: <4C02DD76.2090008 at cse.iitb.ac.in>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Hi,
>
> I have basic block and I want to find a merge node just above this basic
> block.
> How can I do this?
>
> Thanks in advance.
>
> regards,
> Ambika
>
>
> ------------------------------
>
> Message: 3
> Date: Sun, 30 May 2010 18:42:39 -0700
> From: Eric Christopher <echristo at apple.com>
> Subject: Re: [LLVMdev] How difficult is to fix this error: JIT does
>        not     support address-of-label yet! [patch submitted]
> To: Yuri <yuri at rawbw.com>
> Cc: llvmdev at cs.uiuc.edu
> Message-ID: <F2D7213F-F8FC-44A4-9B07-8256C36D1589 at apple.com>
> Content-Type: text/plain; charset=us-ascii
>
>
> On May 30, 2010, at 1:32 PM, Yuri wrote:
>
> > I just implemented this feature and here is the patch:
> > http://llvm.org/bugs/show_bug.cgi?id=7264
>
> Just to follow up to the list Reid replied to this in the bug.  I commented
> as well.
>
> -eric
>
>
> ------------------------------
>
> Message: 4
> Date: Sun, 30 May 2010 23:53:17 -0300
> From: Fabio Kaminski <fabiokaminski at gmail.com>
> Subject: Re: [LLVMdev] LLVM opportunities with Google Native Client
> To: bradchen at google.com
> Cc: llvmdev at cs.uiuc.edu
> Message-ID:
>        <AANLkTimFgmdOXczADU92h4h-Bkl1hhFCfx9SpngSOvIQ at
mail.gmail.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Oww Awsome!!!
>
>
> can we spect the V8 using LLVM some day too?? :)
>
> it will make possible a real browser multilanguage JIT for all the
> compilers
> ported to llvm (why nobody deliver something like that either !?! hehehe)
>
> and the advance in LLVM jit itself (a powerfull dinamic jit)
>
> its very cool to know google is embracing LLVM Platform.. more brainpower
> to
> taking it to the next level!
>
> wish the best in this project..(and remembering how long i had to wait to
> chromium arrives in the linux platform)
>
> On Sat, May 29, 2010 at 5:44 PM, Brad Chen <bradchen at google.com>
wrote:
>
> > Google Native Client <http://code.google.com/p/nativeclient> is
an
> > open-source project working to deliver a native-code environment for
Web
> > browsers that is (at least) as safe and portable as JavaScript and
other
> > technologies we take for granted on the Web. Many LLVM developers have
> > already noticed our recent blog post<
> http://blog.chromium.org/2010/03/native-client-and-web-portability.html>
> about
> > using LLVM as the basis of our instruction set portability strategy.
We
> are
> > looking for a few engineers with deep knowledge of LLVM, code
generation,
> > and system bring-up to join the core team delivering Portable Native
> Client
> > to our developer community.
> >
> > Feel free to contact me at bradchen at google.com for more information
> about
> > the project. Those of you who know Rafael Espindola can also consider
> > contacting him. Rafael recently joined the project full-time.
> >
> > Brad Chen
> > Engineering Manager
> > Google Native Client
> >
> >
> > _______________________________________________
> > LLVM Developers mailing list
> > LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
> >
> >
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> ------------------------------
>
> Message: 5
> Date: Sun, 30 May 2010 23:55:46 -0600
> From: John Criswell <criswell at illinois.edu>
> Subject: Re: [LLVMdev] Finding Merge nodes in CFG
> To: ambika <ambika at cse.iitb.ac.in>
> Cc: "llvmdev at cs.uiuc.edu" <llvmdev at cs.uiuc.edu>
> Message-ID: <4C034F62.7060207 at illinois.edu>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> ambika wrote:
> > Hi,
> >
> > I have basic block and I want to find a merge node just above this
basic
> > block.
> > How can I do this?
> >
>
> Can you clarify what you mean by a "merge node?"  Are you looking
for
> the proper place to insert a phi node?  Are you trying to find the first
> basic block that dominates the basic block of interest, or do you mean
> something else entirely?
>
> -- John T.
>
> > Thanks in advance.
> >
> > regards,
> > Ambika
> > _______________________________________________
> > LLVM Developers mailing list
> > LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
> >
>
>
>
> ------------------------------
>
> Message: 6
> Date: Mon, 31 May 2010 16:32:27 +0930
> From: John Lask <jvlask at hotmail.com>
> Subject: [LLVMdev] libllvm on windows
> To: llvmdev at cs.uiuc.edu
> Message-ID: <BLU0-SMTP66EFCB44694C08EF9B0665C6EE0 at phx.gbl>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> I am looking to use llvm on windows. I know there is a pre-compiled llvm
> windows distribution, but this does not seem to provide libllvm. The
> software that I am looking to use makes use of libllvm (it is unix
> based, but I would like to port it to windows). I really did not wish to
> spend my time compiling llvm (i.e. installing it's dependencies) from
> scratch. What options do I have ?
>
>
> ------------------------------
>
> Message: 7
> Date: Mon, 31 May 2010 11:16:08 +0300
> From: T?r?k Edwin <edwintorok at gmail.com>
> Subject: Re: [LLVMdev] libllvm on windows
> To: llvmdev at cs.uiuc.edu
> Message-ID: <4C037048.4030306 at gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> On 05/31/2010 10:02 AM, John Lask wrote:
> > I am looking to use llvm on windows. I know there is a pre-compiled
llvm
> > windows distribution, but this does not seem to provide libllvm. The
> > software that I am looking to use makes use of libllvm (it is unix
> > based, but I would like to port it to windows). I really did not wish
to
> > spend my time compiling llvm (i.e. installing it's dependencies
>
> There are no dependencies. You just need cmake to generate a visual
> studio project file.
>
> Best regards,
> --Edwin
>
>
> ------------------------------
>
> Message: 8
> Date: Mon, 31 May 2010 16:11:15 +0530
> From: ambika at cse.iitb.ac.in
> Subject: Re: [LLVMdev] Finding Merge nodes in CFG
> To: "John Criswell" <criswell at illinois.edu>
> Cc: "llvmdev at cs.uiuc.edu" <llvmdev at cs.uiuc.edu>
> Message-ID:
>        <4c942266c42a7d8722bd7d3f6fe05be0.squirrel at
www.cse.iitb.ac.in>
> Content-Type: text/plain;charset=iso-8859-1
>
> Actually I have collected some pointer information in the form [ p ->
a,c
> ]. Now suppose at some node I have information as [p->a,c]. Now i want
to
> find a merge node above this node where this information is actually
> geting merged.
> So if I get a merge node above this, I can check in its predecessors if
> their out has only [p->a] or [p->c] and if not so then I will look
for the
> next merge node above this one, and so on.
>
> > ambika wrote:
> >> Hi,
> >>
> >> I have basic block and I want to find a merge node just above this
basic
> >> block.
> >> How can I do this?
> >>
> >
> > Can you clarify what you mean by a "merge node?"  Are you
looking for
> > the proper place to insert a phi node?  Are you trying to find the
first
> > basic block that dominates the basic block of interest, or do you mean
> > something else entirely?
> >
> > -- John T.
> >
> >> Thanks in advance.
> >>
> >> regards,
> >> Ambika
> >> _______________________________________________
> >> LLVM Developers mailing list
> >> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> >> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
> >>
> >
> >
>
>
>
>
> ------------------------------
>
> Message: 9
> Date: Mon, 31 May 2010 15:47:26 +0200
> From: <Kalle.Raiskila at nokia.com>
> Subject: [LLVMdev] Error with instruction selection
> To: <llvmdev at cs.uiuc.edu>
> Message-ID: <1275313646.13411.91.camel at
LLVMbuilder.research.nokia.com>
> Content-Type: text/plain; charset="utf-8"
>
> Hello,
> I'm seeing a miscompilation from the following code:
>
> declare <4 x float>* @getPtr()
> define <4 x float> @func() {
>        %rv1 = call <4 x float>* @getPtr()
>        %rv2 = call <4 x float>* @getPtr()
>        %rv3 = load <4 x float>* %rv1
>        ret <4 x float> %rv3
> }
>
> The load ends up loading from the pointer returned by the 2nd function
> call.
> I traced down the problem to calling the
> SelectionDAGISel::SelectCodeCommon on the load instruction. Before
> calling that the DAG looks OK. The selected target load ends up pointing
> to the "physical function call return register node" instead of
the
> CopyFromReg node that copies the result of the 1st call to a temporary
> register. The physical return register is then overwritten in the next
> call. (This is visible when calling "llc -view-isel-dags
> -view-sched-dags". The first graph is OK, the second is not.)
>
> The problem goes away if I:
> -have the getPtr return anything else than <4xfloat>* or
<4xi32>* (e.g.
> <4xfloat> or float* work just fine)
> -do not load from or store to the pointer - e.g. just returning the
> pointer works.
> -target any other processor than CellSPU (ok, some backends assert on
> this code, and the PIC assebly I didn't understand :) )
>
> Any explanation on what is going on or hints on how to fix this are
> highly appreciated!
>
> thanks,
> kalle
>
>
>
>
> ------------------------------
>
> _______________________________________________
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> End of LLVMdev Digest, Vol 71, Issue 49
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