llvm dev - Apr 2014 - [LLVMdev] How to get debug dump of candidate pairs selected in BBVectorizer?

Hi All,
I'm trying to understand BB Vectorizer and gone through
http://llvm.org/devmtg/2012-04-12/Slides/Hal_Finkel.pdf

Wanted to know how to use bb-vectorize-debug-candidate-selection and
bb-vectorize-debug-pair-selection
command arguments.

I tried the command with debug build clang -

clang -O2 test.c -mllvm -vectorize \
-mllvm -debug-only=bb-vectorize \
-mllvm -bb-vectorize-debug-pair-selection \
-mllvm -bb-vectorize-debug-candidate-selection

as mentioned in http://llvm.org/bugs/show_bug.cgi?id=11973 but it
doesnt seem to dump the candidate pair info as shown in bug id.


Could someone help me out here with the command line argument to get
candidate pair selected info.

Thanks for the help!

Regards

Karthik Bhat
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----- Original Message -----
> From: "Karthik Bhat" <blitz.opensource at gmail.com>
> To: llvmdev at cs.uiuc.edu
> Sent: Thursday, April 24, 2014 6:23:15 AM
> Subject: [LLVMdev] How to get debug dump of candidate pairs selected in
BBVectorizer?
> 
> 
> 
> Hi All,
> I'm trying to understand BB Vectorizer and gone through
> http://llvm.org/devmtg/2012-04-12/Slides/Hal_Finkel.pdf
> 
> 
> Wanted to know how to use bb-vectorize-debug-candidate-selection and
> bb-vectorize-debug-pair-selection command arguments.
> 
> 
> I tried the command with debug build clang -
> clang -O2 test.c -mllvm -vectorize \
> -mllvm -debug-only=bb-vectorize \
> -mllvm -bb-vectorize-debug-pair-selection \
> -mllvm -bb-vectorize-debug-candidate-selection as mentioned in
> http://llvm.org/bugs/show_bug.cgi?id=11973 but it doesnt seem to
> dump the candidate pair info as shown in bug id.
A few things have changed since then. You'll need -vectorize-slp-aggressive
instead of -vectorize.
>From clang, there are now direct flags:
-fvectorize == loop vectorizer
-fslp-vectorize == SLP vectorizer
-fslp-vectorizer-aggressive == BB vectorizer

Also, in case you don't know, most of the active upstream development has
moved to the SLP vectorizer. The BB vectorizer still does a more expensive
search, and I think it is mostly useful at this point for isolating useful cases
that the SLP vectorizer misses.

 -Hal
> 
> Could someone help me out here with the command line argument to get
> candidate pair selected info.
> Thanks for the help! Regards Karthik Bhat
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
> 
-- 
Hal Finkel
Assistant Computational Scientist
Leadership Computing Facility
Argonne National Laboratory

On Thu, Apr 24, 2014 at 11:49 PM, Hal Finkel <hfinkel at anl.gov> wrote:
> ----- Original Message -----
> > From: "Karthik Bhat" <blitz.opensource at gmail.com>
> > To: llvmdev at cs.uiuc.edu
> > Sent: Thursday, April 24, 2014 6:23:15 AM
> > Subject: [LLVMdev] How to get debug dump of candidate pairs selected
in
>       BBVectorizer?
> >
> >
> >
> > Hi All,
> > I'm trying to understand BB Vectorizer and gone through
> > http://llvm.org/devmtg/2012-04-12/Slides/Hal_Finkel.pdf
> >
> >
> > Wanted to know how to use bb-vectorize-debug-candidate-selection and
> > bb-vectorize-debug-pair-selection command arguments.
> >
> >
> > I tried the command with debug build clang -
> > clang -O2 test.c -mllvm -vectorize \
> > -mllvm -debug-only=bb-vectorize \
> > -mllvm -bb-vectorize-debug-pair-selection \
> > -mllvm -bb-vectorize-debug-candidate-selection as mentioned in
> > http://llvm.org/bugs/show_bug.cgi?id=11973 but it doesnt seem to
> > dump the candidate pair info as shown in bug id.
>
> A few things have changed since then. You'll need
> -vectorize-slp-aggressive instead of -vectorize.
>
> From clang, there are now direct flags:
> -fvectorize == loop vectorizer
> -fslp-vectorize == SLP vectorizer
> -fslp-vectorizer-aggressive == BB vectorizer
>
> Also, in case you don't know, most of the active upstream development
has
> moved to the SLP vectorizer. The BB vectorizer still does a more expensive
> search, and I think it is mostly useful at this point for isolating useful
> cases that the SLP vectorizer misses.
>
> Thanks Hal for the info and heads-up. I have started to look into
SLPVectorizer and trying to understand the same.
>  -Hal
>
> >
> > Could someone help me out here with the command line argument to get
> > candidate pair selected info.
> > Thanks for the help! Regards Karthik Bhat
> > _______________________________________________
> > LLVM Developers mailing list
> > LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
> >
>
> --
> Hal Finkel
> Assistant Computational Scientist
> Leadership Computing Facility
> Argonne National Laboratory
>
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