[BUG][GCC] *Serious* optimization bug: Any gcc specialistsout there?

Stephan Rudlof sr at evolgo.de
Fri Aug 4 22:55:20 UTC 2000


PS:

My xcalc calculator program gives the same (-0.74692189) result...

Stephan Rudlof wrote:
> 
> David,
> 
> David Chase wrote:
> >
> > At 04:31 PM 8/4/00 +0200, Stephan Rudlof wrote:
> > >the result strongly differs! (the optimized version gives the *wrong*
> > >result)
> >
> > And those results were? :-)
> 
> Before 'bugfix':
>         1.000000e+20
> and
>         -7.469219e-01;
> after bugfix by using compile flag -D__NO_MATH_INLINES
> in both cases
>         -7.469219e-01
> .
> Reading specs from /usr/lib/gcc-lib/i486-linux/egcs-2.91.66/specs
> gcc version egcs-2.91.66 19990314/Linux (egcs-1.1.2 release)
> 
> Interesting, isn't it?
> 
> > I got identical behavior, in both cases printing:
> > sin(arg1): -6.452513e-01
> >
> > Gcc version:
> > gcc version egcs-2.91.57 19980901 (egcs-1.1 release)
> 
> Which machine/CPU?
> 
> > Checking against two Java implementations:
> > -0.6452512852657808442058
> > (they both agreed, and if rounded to 7 decimal
> > digits, they agree with the C program)
> >
> > Checking against contructive reals calculator:
> > -0.6452512852657808442058117113125230074069...
> > (agrees with Java, if rounded)
> 
> To illuminate this point:
> - Does Java use a C lib to implement double arithmetics?
> - What kind of calculator have you used: A calculator emulated by your
> computer or a separate one (e.g. a Casio)?
> 
> <snipped>
> 
> Greetings,
> 
> Stephan
> 
> --
> Stephan Rudlof (sr at evolgo.de)
>    "Genius doesn't work on an assembly line basis.
>     You can't simply say, 'Today I will be brilliant.'"
>     -- Kirk, "The Ultimate Computer", stardate 4731.3

-- 
Stephan Rudlof (sr at evolgo.de)
   "Genius doesn't work on an assembly line basis.
    You can't simply say, 'Today I will be brilliant.'"
    -- Kirk, "The Ultimate Computer", stardate 4731.3





More information about the Squeak-dev mailing list