text: Mark Mitchell - Re: SPE configuration in GCC
  Re: SPE configuration in GCC
  Cc: Aldy Hernandez <aldyh at redhat dot com>, gcc at gcc dot gnu dot org
  Date: Mon, 17 Jan 2005 11:20:43 -0800
  Subject: Re: SPE configuration in GCC
  References: <41EBED9D.4080405@codesourcery.com> <20050117170251.GB15418@redhat.com> <41EBF0E3.702@codesourcery.com> <200501171735.j0HHZgD27288@makai.watson.ibm.com> <41EBF9CB.6000901@codesourcery.com> <200501171859.j0HIxlD27638@makai.watson.ibm.com>
  As Aldy mentioned, there already is a powerpc-linuxspe
  configuration that seems to do what your customer wants.
  gcc/config/rs6000/linuxspe.h makes the options active and defaults to a
  8540 scheduling model, but does not enable the SPE features by default.
  I don't think that's quite true. It seems to default to enabling SPE via SUBTARGET_OVERRIDE_OIPTIONS. It also passes "-mspe -me500" to the assembler unconditionally. Our customer wants SPE to be an option, not the default.
  I am wliling to consider a patch to rs6000.h and the other
  headers, but I am not sure what benefit it provides over the
  configurations that Aldy already designed and implemented.
  I think that the best solution, then, is probably a new configuration header for this customer. That's easy enough to arrange. We've certainly established that the current situation is a conscious choice, which was my primary objective.
  As a secondary issue, it would be nice to have a GCC-wide policy about whether "target-elf" should support all variants of a chip, or just some. Based on my knowledge of users, I'd suggest that it should support all variants.
  As another secondary issue, I consider it a bug in the PowerPC back end that command-line options (like -misel) are silently ignored in the default configuration. If you agree, I can file a PR about that.