llvm dev - Aug 2011 - [LLVMdev] scalar evolution to determine access functions in arays

Only because in my next passes I change the CFG significantly and it is very
hard to maintain the values of the Phi nodes.

Alexandra



________________________________
From: Tobias Grosser <tobias at grosser.es>
To: Jimborean Alexandra <xinfinity_a at yahoo.com>
Cc: "llvmdev at cs.uiuc.edu" <llvmdev at cs.uiuc.edu>;
"luismastrangelo at gmail.com" <luismastrangelo at gmail.com>
Sent: Wednesday, August 3, 2011 9:36 AM
Subject: Re: [LLVMdev] scalar evolution to determine access functions in arays

On 08/03/2011 08:35 AM, Jimborean Alexandra wrote:
> Hello Tobi,
>
> You are right, we need to run some other passes before running the
> scalar evolution pass. The sequence that I run for this example is -O3
> -loop-simplify -reg2mem. This is why I did not obtain the expressions
> depending on the loop indices. So I removed the reg2mem pass and scalar
> evolution computes the correct functions.
>
> However, I need to run the reg2mem pass (or any other that would
> eliminate the phi nodes) before calling my own passes. So probably we
> are going to run the scalar evolution on the code containing the phi
> nodes, run reg2mem and try to identify the original variables in the new
> code built after reg2mem.
Just out of interest. Why do you need to run the reg2mem pass?

Cheers
Tobi
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On 08/03/2011 10:22 AM, Jimborean Alexandra wrote:
> Only because in my next passes I change the CFG significantly and it is
> very hard to maintain the values of the Phi nodes.
OK. In Polly we developed a pass called, 'independent-blocks-pass'. It 
basically creates basic blocks, that can easily be rescheduled without 
stopping the scalar evolution analysis to work. Maybe something similar 
can help you. Details about this pass are available in my thesis.

Cheers
Tobi

Ok, thank you, I will have a look and reply with questions if necessary. Does it
take into consideration the existing phi nodes?

Alexandra



________________________________
From: Tobias Grosser <tobias at grosser.es>
To: Jimborean Alexandra <xinfinity_a at yahoo.com>
Cc: "llvmdev at cs.uiuc.edu" <llvmdev at cs.uiuc.edu>;
"luismastrangelo at gmail.com" <luismastrangelo at gmail.com>
Sent: Wednesday, August 3, 2011 11:26 AM
Subject: Re: [LLVMdev] scalar evolution to determine access functions in arays

On 08/03/2011 10:22 AM, Jimborean Alexandra wrote:
> Only because in my next passes I change the CFG significantly and it is
> very hard to maintain the values of the Phi nodes.
OK. In Polly we developed a pass called, 'independent-blocks-pass'. It
basically creates basic blocks, that can easily be rescheduled without stopping
the scalar evolution analysis to work. Maybe something similar can help you.
Details about this pass are available in my thesis.

Cheers
Tobi
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