Expensive bounds checking (was: Unsafe Optimizations

James Larus writes in <1990Jun14.152939.2578@esegue.segue.boston.ma.us>:


> [discussion of Gupta's Sigplan90 paper] ... After all optimizations were
>applied, programs with bounds checkings [still] ran 0-46% slower than
>programs without bounds checking (down from 78-325% slower). That's a
>pretty large performance degredation ...


Upcoming superscalar architectures offer an opportunity to perform bounds
checking concurrently with other operations. Propagating these checks out
of the critical path of computation (e.g. with techniques such as those
suggested by Gupta) may yield additional safety with little degradation.


It would make a nice change if the next generation of whizbang machines were
not only faster, but "safer" too!


--\-- Jan Prins (prins@cs.unc.edu) "The claim is `always'...
    / Computer Science Dept. ... no, wait, it is `never'..."
--\-- UNC Chapel Hill
--

Return to the comp.compilers page.
Search the comp.compilers archives again.