9 Jan 2001 23:13:21 -0500

Related articles |
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[3 earlier articles] |

Re: non trivial constant folding pat@jantar.org (Patryk Zadarnowski) (2001-01-06) |

Re: non trivial constant folding bonzini@gnu.org (2001-01-06) |

Re: non trivial constant folding idbaxter@semdesigns.com (Ira D. Baxter) (2001-01-06) |

Re: non trivial constant folding cfc@world.std.com (Chris F Clark) (2001-01-06) |

Re: non trivial constant folding anton@mips.complang.tuwien.ac.at (2001-01-09) |

Re: non trivial constant folding anton@mips.complang.tuwien.ac.at (2001-01-09) |

Re: non trivial constant folding metzger@rsn.hp.com (Robert Metzger) (2001-01-09) |

Re: non trivial constant folding sjmeyer@www.tdl.com (2001-01-09) |

Re: non trivial constant folding henry@spsystems.net (2001-01-09) |

Re: non trivial constant folding dew@cray.com (2001-01-09) |

Re: non trivial constant folding mpointie@eden-studios.fr (Mickaël Pointier) (2001-01-09) |

Re: non trivial constant folding morrell@morrell.cup.hp.com (Michael Morrell) (2001-01-09) |

Re: non trivial constant folding dmr@bell-labs.com (Dennis Ritchie) (2001-01-11) |

[7 later articles] |

From: | Robert Metzger <metzger@rsn.hp.com> |

Newsgroups: | comp.compilers |

Date: | 9 Jan 2001 23:13:21 -0500 |

Organization: | Compilers Central |

References: | 01-01-015 |

Keywords: | arithmetic, optimize |

Posted-Date: | 09 Jan 2001 23:13:21 EST |

On 5 Jan 2001, Mickaël Pointier wrote:

*> My problem is that I do not manage to find a clean solution*

*> to optimise this:*

*>*

*> eval(1+var+1)*

*>*

*> [I've seen compilers that do that. With associative operators like +*

*> they combine all of the operands of a set of cascaded operators into*

*> a list or array, then sort that array to get the constants together.*

*> -John]*

You will find several methods to convert expressions to a canonical form,

which includes your example as a special case, in Chapter 6

"Converting to a Canonical Form" in

Automatic Algorithm Recognition and Replacement:

A New Approach to Program Optimization,

R. Metzger and Z. Wen, MIT Press, 2000.

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Robert Metzger | TEL (972) 497-4437 | 3000 Waterview Parkway

Technical Solutions Lab | FAX (972) 497-4245 | P.O. Box 833851

Hewlett-Packard Company | metzger@rsn.hp.com | Richardson, TX 75080-3851

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