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Re: Obsolete powerpc*-*-*spe*
- From: Olivier Hainque <hainque at adacore dot com>
- To: Segher Boessenkool <segher at kernel dot crashing dot org>
- Cc: Olivier Hainque <hainque at adacore dot com>, Andrew Jenner <andrew at codesourcery dot com>, David Edelsohn <dje dot gcc at gmail dot com>, GCC Development <gcc at gcc dot gnu dot org>, Sandra Loosemore <sandra at codesourcery dot com>, Arnaud Charlet <charlet at adacore dot com>, Joel Brobecker <brobecker at adacore dot com>
- Date: Wed, 15 Mar 2017 17:16:06 +0100
- Subject: Re: Obsolete powerpc*-*-*spe*
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> On Mar 15, 2017, at 15:26 , Segher Boessenkool <email@example.com> wrote:
> I do not think VLE can get in, not in its current shape at least. VLE
> is very unlike PowerPC in many ways so it comes at a very big cost to
> the port (maintenance and otherwise -- maintenance is what I care about
> Since SPE and VLE only share the part of the rs6000 port that doesn't
> change at all (except for a bug fix once or twice a year), and everything
> else needs special cases all over the place, it seems to me it would be
> best for everyone if we split the rs6000 port in two, one for SPE and VLE
> and one for the rest. Both ports could then be very significantly
> I am assuming SPE and VLE do not support AltiVec or 64-bit PowerPC,
> please correct me if that is incorrect. Also, is "normal" floating
> point supported at all?
> Do you (AdaCore and Mentor) think splitting the port is a good idea?
That's actually an option we considered.
We haven't gone very far in studying what this would entail and were still
unclear on how much of a clean separation we could get without risking the
introduction of (too much) instability.
It seemed like avoiding code duplication (that would otherwise be a maintenance
issue) might require refactoring in sensitive areas, e.g. prologue/epilogue
expansion, but the perspective of getting two variants simpler to grasp on top
of common code definitely sounds attractive and worth some effort.