-O generates NaN

[Phil Edwards]

On Sat, Mar 03, 2001 at 03:01:58PM -0300, Alexandre Oliva wrote:
> On Mar  2, 2001, Haruhiko Okumura <okumura@matsusaka-u.ac.jp> wrote:
> 
> > Could someone tell why this code generates lots of NaN's when compiled
> > with any optimization flag (-O, -O2 etc) on?
> 
> Probably some of the math optimizations in GNU libc.  Not libstdc++.

I concur.  On Solaris 8 -- therefore not using GNU libc -- I always see
the same results:

     2: 85.9715
     6: 85.9715
     18: 85.9715
     2: 86.5915
     6: 86.5915
     18: 86.5915
    len1 = 85.9715, len2 = 86.5915

That is the output with no optimization, with -O, and with -O3.


Phil

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