Re: Last IRIX "make check" problem.

[Lowell Johnson <ldjohn at usgs dot gov>]

On Tue, 04 Sep 2001, Brian Gough wrote:
> Lowell Johnson writes:
>  > FAIL: gsl_isinf(inf) (0 observed vs 1 expected)
>  > ...
>  > 
>  > It appears that the following lines in sys/infnan.c
>  > 
>  >   int status = (x != x);
>  >   double y = x - x;
>  > 
>  > are not serving their intended purposes?
> 
> Thanks for the bug report. Are you using the irix compiler?
> If so, is this the problem? (from the cc manpage),
> 
>  IEEE_comparisons[=(OFF|ON)] Force all comparisons to yield
>    results conforming to the IEEE 754 standard for NaN and Inf operands.
>    If this option is OFF (the default case), certain optimizations will
>    produce non- IEEE results for comparisons involving NaN and Inf
>    values, e.g. 'x==x' will be treated as TRUE without executing a test.

Yes, we are using the IRIX MIPSpro C compiler, and yes, the
IEEE_comparisons=ON did the trick.  Thanks.

Unfortunately, it appears that our cc man page may be a bit out of date. 
When we first started looking at compiler options for our problem, we
didn't come across anything.  Then when you suggested the IEEE_comparisons
option, I did a search in the man page and ... it wasn't there!  Then we
noticed the man page header says "Last changed: 4-15-99".  We know that
our compiler version is newer than that, so we figured the IEEE_comparisons
option is available but didn't know how to invoke it.   After a couple of
trial and errors, we got it to work with -OPT:IEEE_comparisons=ON.

What is the last changed date on your IRIX cc manpage?

Thanks again for the fix.


    Lowell

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