Re: SIGFPE, Arithmetic exception. "Value optimized out" when using --ffast-math

[Steve Kargl <sgk at troutmask dot apl dot washington dot edu>]

On Wed, Jun 29, 2011 at 04:29:00PM -0400, Paul van Delst wrote:
> 
> As I mentioned above, if we remove the --ffast-math option
> during compilation, the code run correctly through to completion.
> 
> Is this related in any way to:
>   http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40005
> ?

Are you sure you grabbed the right PR number?  If my
quick scan of the audit trail for 40005 is correct,
40005 was concerned with a segfault of gfortran not
the executable created by gfortran.

> If so, is there a fix for the v4.4 of gfortran on x86_64?
> We won't be allowed to install 4.5 or 4.6 until RHE6 passes
> whatever security tests they are currently being subjected to).

Given the above statement, I suspect that the code is
unavailable to gfortran developers.  The only way to
know with certainty if 4.5 or 4.6 works for your code
is to try them.

PS:  I rarely use --fast-math when I compile my own codes.
It is a misnamed option in IMHO.  Yes, one may get a faster
executable.  Unfortunately, one may also get the wrong result.
FWIW, my typical set of options are 

-O2 -pipe -march=native -funroll-loops -ftree-vectorize

-- 
Steve