Release 0.96 of Petit

Petit is a research tool for dependence analysis and program transformations developed from Michael Wolfe's Tiny Tool. Petit was developed at the University of Maryland by the Omega Project. Petit operates on programs in a simple Fortran-like language.

Petit relies on the the Omega Library for performing its analyses. The library is a system for building, manipulating, and querying sets of integer tuples and relations between integer tuples. The current release is a minor release that contains a directory reorganization and some changes to support the current release of Petit.

Features of Petit include:

• Memory- and Value-based dependence analysis, based on the Omega test
• Nonlinear dependence analysis using uninterpreted function symbols
• Capabilities that improve the accuracy of data dependence analysis (induction variable recognition, forward substitution).
• An interface for building new analyses that simplifies building sets of constraints describing programs
• An interface to allow easier integration of our dependence analysis techniques into other compilers
• A program transformation system for finding computation decompositions (not available in this release)
• An X Window System / Motif interface for examining programs and dependence relations

Petit is available for FTP at ftp://ftp.cs.umd.edu/pub/omega/petit. Petit uses the Omega Library to perform its analyses; the library is available at ftp://ftp.cs.umd.edu/pub/omega/omega_library.

This implementation is a research prototype and has not been subjected to rigorous testing. In other words: THERE ARE BUGS IN THIS SOFTWARE We don't know of any at the moment (other that the ones listed under KNOWN BUGS/LIMITATIONS below), but we are sure that other, undiscovered bugs remain in the software.

If you register with us as someone who has a copy of the Petit, we will send you update notices. Send email to omega@cs.umd.edu to be added to the list of registered users.

We welcome any research groups to incorporate our software into their compilers. Please stay in contact with us if you plan to make serious us of Petit or the Omega Library so that we can provide you with updates and get feedback from your use.

We are grateful to Michael Wolfe for placing tiny in the public domain, which allowed us to build on top of his software.

The implementation of the Omega test and extensions to petit have been done by a number of people at the University of Maryland:

• Udayan Borkar
• Wayne Kelly
• Evan Rosser
• Vadim Maslov
• William Pugh
• Tatiana Shpeisman
• Jerry Sobieski
• Dave Wonnacott

Our work on this software has been supported by NSF grants CCR-8908900 and CCR-9157384 and by a Packard Fellowship, as well as being based on Michael Wolfe's original implementation of tiny.

Files

README

This file

WOLFE_README

The readme file that originally accompanied Michael Wolfe's distribution of tiny

src.tar.Z

Source for petit and f2t, a FORTRAN to petit converter

sparc_demo.tar.Z

Sun Sparc executable versions of the programs that can be made from the src files, plus demo files, and documentation.

decstation_demo.tar.Z

Decstation executable versions of the programs that can be made from the src files, plus demo files and documentation.

demo.tar.Z

Test files for demos

test.tar.Z

Regression test files

doc.tar.Z

Some documentation

Together, these tar files constitute the entire petit system, with the following directories:

include

header files (from src.tar.Z)

src

source code (from src.tar.Z)

obj

makefile (from src.tar.Z), generated files (from sparc_demo.tar)

doc

documentation for petit

demo

sample files documented to show features of the Omega test and petit

f2t

A FORTRAN to petit converter based on f2c (from src.tar.Z)

rt

regression test sample files and expected results (from test.tar.Z)

misc

shell scripts used for regression testing (rt.tar and src.tar)

The executable programs are:

petit

the petit environment, upgraded to use the omega test and test for refinement, killing, and covering of dependences

f2t

A FORTRAN to petit converter based on f2c

And remember: Pugh's extended tiny isn't tiny.

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