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Re: Move TEST_f_f tests for [a-c]* functions from to auto-libm-test-in

On Sat, 30 Nov 2013, Joseph S. Myers wrote:

> 	(output_for_one_input_case): Do not require ERANGE on underflow to
> 	zero if round-to-nearest result does not underflow to zero, unless
> 	exact results required.

I should have explained this change.  Examining the generated test output 
showed cases (atan of the least subnormal input in a directed rounding 
mode) where the expected underflowing result is 0, so errno of ERANGE is 
expected - but implementations may well just return the input value (which 
is just a 1ulp error compared to the correctly rounded value, or a tiny 
fraction of 1ulp compared to the mathematical result) in which case they 
would also not generate ERANGE (if the result is checked against 0 to 
determine whether to generate ERANGE, which we decided to allow in our 
errno goals).  Really the expectation is "ERANGE if the result is 0, but 
ERANGE optional if the result is not 0", but as that's not something currently supports - tests for errno and exceptions are 
independent of what the actual result returned was - it's best represented 
as "ERANGE optional" (much like cases very close to the underflow 
threshold are "underflow optional" when if the actual value returned is 
subnormal they should be "underflow required").

Joseph S. Myers

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