"John D. McCalpin" <>
1 Nov 91 13:35:16 GMT

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Related articles
Loop ROLLING (1991-10-25)
Re: Loop ROLLING (1991-10-28)
Re: Loop ROLLING (John D. McCalpin) (1991-11-01)
Re: Loop ROLLING (1991-11-01)
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Newsgroups: comp.compilers
From: "John D. McCalpin" <>
Keywords: Fortran, optimize
Organization: College of Marine Studies, U. Del.
References: 91-10-103
Date: 1 Nov 91 13:35:16 GMT

>> On 25 Oct 91 15:47:13 GMT, (Rick Gorton) said:
Rick> I'm looking for information on loop ROLLING, and no-one I've
Rick> talked to can recall seeing anything specific about this topic.

I seem to recall that the Pacific Sierra VAST family of Fortran
source-to-source preprocessors are able to re-roll loops to help the
vectorizors see that a "normal" vector construct is present. This memory
is from working on the ETA-10G, so I suspect that their current products
have even more functionality in this regard.

The preprocessor from Kuck and Associates that is used by the IBM XLF
version 2 compiler will re-roll and then unroll simple do loops. I have
not tried it on terribly complicated loops, though. Since HP also uses a
Kuck and Associates preprocessor, their compiler should be able to do this
as well.
John D. McCalpin
Assistant Professor
College of Marine Studies, U. Del. DELOCN::MCCALPIN (SPAN)


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