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Re: [PATCH] Evaluate pow(x,n) at compile-time


 > That's on x86, where glibc uses the hardware, and suffers due to
 > various design/use problems with it.  The functions I referred to are
 > used on sane machines like sparc and powerpc.
 > 
 > While the paper is interesting, you can't prove correctness by running
 > a few thousand testcases.  If you wanted to prove correctness by
 > testing, you have to test *every* input value, all 2^64 of them, or
 > offer some argument that you only need to check a subset.

If you reject a patch IMHO you need to provide a roadmap which leads
towards acceptance.  I.e. tell Roger specifically what he needs to do
in order to get it accepted.  If there is some subset-test or argument
he could provide you must tell him what it is.  Otherwise we'll simply
discourage him from submitting his contributions.  E.g. how was the
pow routine in glibc proved safe enough?

Some people seem to be so afraid of touching the floating point stuff
that we risk never being able to improve it.  If we follow this course
of action we'll fall behind competitor compilers who have better
implementations.

--
Kaveh R. Ghazi			ghazi at caip dot rutgers dot edu


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