Re: Suggested new warning.

[Jeffrey A Law <law at cygnus dot com>]

  In message <199906151206.OAA14325@rtssun5.rtsffm.com>you write:
  > 
  > 
  > Dear egcs/gcc maintainers,
  > 
  > recently we had a bug to fix which boiled down to the mistake that two
  > floating point numbers were compared using "==" or "!=". Both were
  > only almost equal of course. Thinking about how to find similar places
  > in our code body, I found it most easiest to enhance the compiler by a
  > warning.
  > 
  > The following patch to egcs-19990608 introduces a warning when
  > floating point operands are compared using "==" or "!=".
  > 
  > Testing this with our code the warning barfed at lots of places where
  > comparision with 0.0 were made. It is unlikely that we'll want to
  > change such places. Therefore a further improvement might be, not to
  > warn when one of the operands is a constant.
  > 
  > Although not perfect yet, I'd suggest incorporation of this little
  > enhancement. It is turned off by default. So nobody will be surprised
  > unpleasently.
  > 
  > Best regards
  > 
  > Dirk Zoller
  > 
  > Here is the patch:
[ ... ]
Sorry it took so long to get back to this patch.

I think it's an excellent idea too.  I updated the patch to apply to the
current sources, added some documentation to invoke.texi and installed it.

Thanks,
jeff