Re: (-Os versus -O2 relation) Was: case where gcc generates bigger binaries than MSVC

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

  In message <200005112015.NAA06576@kankakee.wrs.com>you write:
  > > Date: Thu, 11 May 2000 10:25:16 +0200
  > > From: Jan Hubicka <jh@suse.cz>
  > > To: egcs@egcs.cygnus.com, law@cygnus.com, mat@lcs.mit.edu
  > 
  > > I am not sure about DATA_ALIGNMENT. The decision IMO that needs to
  > > be made is whether we want -O2 and -Os code to be combined.
  > 
  > There are alignments that are mandated by the ABI, don't follow them,
  > and there isn't compatibility.  Those cannot change with -Os.  The
  > optional/extra alignments that don't interfere (except with
  > performance) with interworking of ABI compliant code, should be
  > affected by -Os.
  > 
  > If gcc smears these two cases together in a port file, then we need to
  > unsmear them and expose the difference to the compiler.  We could try
  > and have the port files make use of the -Os flag, but in the end, I
  > don't think that would be better.
Any port which uses DATA_ALIGNMENT or CONSTANT_ALIGNMENT to handle ABI
mandated alignments is broken.  There are other mechanisms for handling
required alignments.
jeff