[llvm-dev] [RFC][SVE] Supporting SIMD instruction sets with variable vector lengths

[Hal Finkel via llvm-dev]

On 08/01/2018 02:59 PM, Robin Kruppe wrote:
> On 1 August 2018 at 18:26, Hal Finkel <hfinkel at anl.gov> wrote:
>> On 08/01/2018 06:15 AM, Renato Golin wrote:
>>> On Tue, 31 Jul 2018 at 23:46, Hal Finkel via llvm-dev
>>> <llvm-dev at lists.llvm.org> wrote:
>>>> In some sense, if you make vscale dynamic,
>>>> you've introduced dependent types into LLVM's type system, but you've
>>>> done it in an implicit manner. It's not clear to me that works. If we
>>>> need dependent types, then an explicit dependence seems better. (e.g.,
>>>> <scalable <n> x %vscale_var x <type>>)
>>> That's a shift from the current proposal and I think we can think
>>> about it after the current changes. For now, both SVE and RISC-V are
>>> proposing function boundaries for changes in vscale.
>> I understand. I'm afraid that the function-boundary idea doesn't work
>> reasonably.
> FWIW, I don't think dependent types really help with the code motion
> problems.

Good point.

...

-- 
Hal Finkel
Lead, Compiler Technology and Programming Languages
Leadership Computing Facility
Argonne National Laboratory