Re: Bug with g77 and -mieee on Alpha Linux

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

  In message <19990711224024.27602.qmail@deer>you write:
  > Richard Henderson pointed out that, probably, the default for *libraries*
  > should be -mieee, with multlibbed -mno-ieee versions being provided only
  > *after* we find, via profiling or whatever, to be necessary to obtain
  > expected performance on real code.  (Well, I've enhanced the wording on
  > his position a bit -- hope I haven't misstated it as a result.)
Interesting way to look at the problem.  I'm not sure if I agree, but it is
interesting and worth some thought.

  > It's too late to make -mieee the default for 2.95, unless we significantly
  > slip the schedule.
I agree.

  > As with -fno-emulate-complex, when and if we ever try to make it the
  > default, we're therefore quite likely to find "show-stopper" bugs in
  > the release that is intended to accomplish that default change, due
  > to the upwards curve in worldwide testing of the default as we near
  > the actual release.
The difference between these two cases is in the -f[no]emulate-complex we
aren't even sure *what* the compiler should be doing, much less *how* to
get it done.

There's a rather serious design issue that needs to be investigated before we
can even begin to look at solutions.  Worse yet, the investigation phase will
probably require looking at a variety of other Fortran compilers to see how
they handle passing of complex values -- we should not insert a gratuitous ABI
incompatibility for passing complex values.

Letting the release out with -fno-emulate-complex without resolving these 
issues
makes it much more likely that we will need to break binary compatibility 
again for the Fortran compiler once we figure out how to properly pass complex
values.

I haven't made a final decision on the complex stuff, but I'll have to make one
in the very near future (next 24hrs).  

jeff