EQNTOTT-Specific Optimizations

cdg@nullstone.com (Christopher Glaeser)
19 Dec 1995 23:11:13 -0500

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EQNTOTT-Specific Optimizations cdg@nullstone.com (1995-12-19)
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From: cdg@nullstone.com (Christopher Glaeser)
Newsgroups: comp.compilers
Date: 19 Dec 1995 23:11:13 -0500
Organization: Compilers Central
Keywords: C, optimize

I received several requests for additional information regarding
EQNTOTT-Specific optimizations and pattern matching, and have codified
several tests which exhibit these issues and defects.

Some compilers use EQNTOTT-specific optimizations to achieve the best
possible run-time performance. Examples include compilers that

1) Generate exceptionally good code for EQNTOTT, but generate poor code
      for programs that are only slightly different from EQNTOTT; and,
2) Generate EQNTOTT code for programs that are very similar to EQNTOTT
      but are not semantically equivalent.

A more complete description is available at

The sources for the test files that exhibit these optimizations and
defects are available at

Although EQNTOTT has not been included in SPEC95, the issues relating
to benchmark-specific optimizations, and in particular, which
optimizations should be allowed when reporting SPEC results, is still
the subject of debate.

Best regards,
Christopher Glaeser cdg@nullstone.com
Nullstone Corporation http://www.nullstone.com


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