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RE: about LNO

To: Peng Tu <tu@xxxxxxxxxxxxx>
Subject: RE: about LNO
From: Ziang Hu <hu@xxxxxxxxxxxxxxxxxxx>
Date: Tue, 12 Sep 2000 20:42:50 -0400 (EDT)
Cc: 'Ziang Hu' <hu@xxxxxxxxxxxxxxxxxxx>, "pro64-support@xxxxxxxxxxx" <pro64-support@xxxxxxxxxxx>
In-reply-to: <01C01CD6.A4E64F70.tu@xxxxxxxxxxxxx>
Sender: owner-pro64-support@xxxxxxxxxxx
I mean loop interchange. Generally, MipsPro will do loop interchange and
tiling with this code.

Thanks

Hu

On Tue, 12 Sep 2000, Peng Tu wrote:

> For this C program, I don't see why it is beneficial to interchange
> the loop because the inner loop is already stride-1 (C is row-major).
> 
> It does need an unroll-and-jam transformation to capture the reuse
> of the outer loop though.  Maybe the LNO machine model is not up-to-date
> with the IA64.
> 
> A useful flag to try for C program is -OPT:alias=restrict if the array is
> an input parameter.
> 
> Peng.
> 
> On Tuesday, September 12, 2000 11:07 AM, Ziang Hu 
> [SMTP:hu@xxxxxxxxxxxxxxxxxxx] wrote:
> > 
> > Hi, 
> > 
> > I tried to test the effect of LNO with Pro64. The code is as follows:
> > 
> >      ...     
> >      for (i=0; i<1000; i++)
> >         for (j=0; j<1000; j++)
> >             a[i][j] = a[i][j] + a[i-1][j];
> >      ...
> > 
> > With -O3, no loop interchange happened.
> > 
> > How about LNO with C programs ?
> > 
> > Thanks
> > 
> > Ziang
> 


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