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RE: [MIPS] Add sbasic supoert ffor MSA (SIMD)
- From: Matthew Fortune <Matthew dot Fortune at imgtec dot com>
- To: Mike Stump <mikestump at comcast dot net>, Richard Sandiford <rdsandiford at googlemail dot com>
- Cc: "Joseph S. Myers" <joseph at codesourcery dot com>, Graham Stott <Graham dot Stott at imgtec dot com>, "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>, Ilie Garbacea <Ilie dot Garbacea at imgtec dot com>, "Rich Fuhler" <Rich dot Fuhler at imgtec dot com>, Doug Gilmore <Doug dot Gilmore at imgtec dot com>, Richard Earnshaw <rearnsha at arm dot com>
- Date: Thu, 29 May 2014 09:09:43 +0000
- Subject: RE: [MIPS] Add sbasic supoert ffor MSA (SIMD)
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- References: <83760FF4D445E74A822AAB0E7BFE5F754051CCC4 at KLMAIL01 dot kl dot imgtec dot org> <Pine dot LNX dot 4 dot 64 dot 1405211752490 dot 13941 at digraph dot polyomino dot org dot uk> <6D39441BF12EF246A7ABCE6654B02353540655 at LEMAIL01 dot le dot imgtec dot org> <5385F26F dot 2030603 at arm dot com> <48022FA6-3176-4DC0-9E84-2390EF8F2373 at comcast dot net>
Mike Stump <email@example.com> writes:
> On May 28, 2014, at 7:27 AM, Richard Earnshaw <firstname.lastname@example.org> wrote:
> > Speed of implementation. We're gradually replacing these with proper
> > builtins, but that takes a lot more work.
> As an owner of a port with more builtins that yours, I can offer a
> technological solution to reduce the cost of builtins to:
> (define_builtin "my_stop"
> (define_outputs [(void_operand 0)])
> (define_rtl_pattern "my_stop" )
> (define_insn "my_stop"
> [(unspec_volatile [(const_int 0)]
> for example. This creates the builtins, allows overloading, allows
> input/output parameters, can reorder operands, allows for complex types,
> allows memory reference parameters, allows pure markings, does vectors,
> conditional availability, generates documentation, creates test suites and
> more. If you wire up a speaker it even sings.
> Someone would have have to step forward with a need and some time to port
> their port over to the new scheme and help with the reason for why the
> technology should go in. It is mostly contained in 5600 lines of self
> contained python code, and is built to solve the problem generally. It adds
> about 800 lines to builtins.c. It has a macro system that is more powerful
> than the macro system .md files use, so one gets to share and collapse
> builtins rather nicely. It is known to work for C and C++. Other languages
> may need extending; C for example cost is around 250 lines to support.
Myself and others at IMG would be interested in reviewing/evaluating the
implementation and assuming it looks useful then we would of course help to
get it in shape for submission.
> One promise, you will never have to create an argument list, or a type, for
> example here is a two output, type input functional instruction with some
> doc content:
> (define_mode_iterator MYTYPE
> [V8QI V4HI V2SI DI ...])
> (define_builtin "my_foo" "my_foo2_<type>"
> (define_desc "Doc string for operation")
> (define_outputs [(var_operand:T_MYTYPE 0)
> (var_operand:T_MYTYPE 1)])
> (define_inputs [(var_operand:T_MYTYPE 2)
> (var_operand:T_MYTYPE 3)])
> (define_rtl_pattern "my_foo2_<mode>" [0 2 1 3])
> (attributes [pure])
> I stripped it so you can't know what the instruction was, but you get a
> flavor of multiple outputs, doc bits, pure, overloading, arguments and
> argument rearranging.
Can you post the implementation as an RFC? I suspect the python aspect
will cause the most trouble as GCC builds do not currently require python
I guess that could change depending on the value added. Otherwise it would
be a rewrite I guess.
Before digging in too deep though it would be useful to know if RichardS
would be willing to consider this kind of thing for the MIPS port?