Re: module level flags

[Bruce Korb]

Tim Prince wrote:
> 
> On Saturday 28 September 2002 16:05, Bruce Korb wrote:
> > As best as I can determine, there is no easy way to say, "do
> > not optimize this particular module".  The best way would be
> > with a #pragma around the problematical function, but I'll
> > be happy with anything that does not disable optimization for
> > the entire program and does not prevent someone from overriding
> > CFLAGS for that module, either.  Suggestions?  Thanks!
> So you've ruled out the old-fashioned way of dividing your source into
> separate files, and specifying specific compile flags for the one you don't
> want optimized?  Every make-like compiler driver supports this.  Certain
> compilers support in-file specification of compile flags, subroutine by
> subroutine, and more may do so.  Do you mean something which works with all
> Fortran compilers, past, present, and future, since you haven't specified?

I was trying to do several things without getting excessively verbose.
Insead I was probably obtuse:

1.  lobby for GCC to have #pragma push_optimize 0/#pragma pop_optimize
2.  lobby for automake to support spitting out specialized rules
    when it sees ``autogen_defReduce_c_CFLAGS = -O0''.  Hopefully,
    it (or libtool) is smart enough to strip extra optimizer specs
    for compilers that choke and respell them for other compilers.
3.  not force the compilers with working optimizers to use -O0
    (This is a GCC-3.x issue.  Prior releases and other compilers
    do not have this problem.)
4.  Query the community for usual and customary practices for
    working around the issue, if there are any.

So, yes, I know about making a specialized rule.  The problem is
it also gets all tangled up in configury issues.  e.g., Sun
spells "optimize 2" as ``-xO2''.  Yummy.

For the time being, I'll test for GCC 3.[12] and disable
optimization for that compiler, I guess.  :-(