15 Jul 2002 23:49:19 -0400

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Cross-level optimization NickM@astrosoft.ru (Nikolai Mikhailov) (2002-07-15) |

From: | "Nikolai Mikhailov" <NickM@astrosoft.ru> |

Newsgroups: | comp.compilers |

Date: | 15 Jul 2002 23:49:19 -0400 |

Organization: | Compilers Central |

Keywords: | optimize, question |

Posted-Date: | 15 Jul 2002 23:49:17 EDT |

Algorithm for determinig common-subexpression is well-known, but in case of

presence 20 different common-subexpressions with sophisticated relations we

should decide which to eliminate.

Also depend on target machines some subexpressions should be eliminated and

other shouldn't.

[Example]

x = a + 4 * b;

y = a + 4 * b;

In some machene it would be a good practice to calculate (a+b) only once,

but it produce 3 assignment vs 2 in sample.

The problem is to taking into account target-specific during hi-level

optimization.

This is a common problem but I havn't found any reference for this theme.

I'm working on such algorithm and looking for any literature about this

theme (preferable in e-form) for comparing.

Best regards,

Nikolay Mikhaylov

Astrosoft Research Lab.

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