similar to: vectorisation, risc-v

On Tuesday, October 1, 2019, Jacob Lifshay <programmerjake at gmail.com> wrote: > On Mon, Sep 30, 2019 at 2:30 AM Sander De Smalen via llvm-dev > <llvm-dev at lists.llvm.org> wrote: > > > > I've posted two patches on Phabricator to add support for VScale in LLVM. Excellent! > > > > A brief recap on `vscale`: > > The scalable vector type in

I've posted two patches on Phabricator to add support for VScale in LLVM. A brief recap on `vscale`: The scalable vector type in LLVM IR is defined as `<vscale x n x m>`, to create types such as `<vscale x 16 x i8>` for a scalable vector with at least 16 bytes. In the definition of the scalable type, `vscale` is specified as a positive constant of type integer that will only be

On Tue, Oct 1, 2019 at 11:08 AM Graham Hunter <Graham.Hunter at arm.com> wrote: > Hi Luke, hi graham, thanks for responding in such an informative fashion. > > On 1 Oct 2019, at 09:21, Luke Kenneth Casson Leighton via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > typedef vec4 float[4]; // SEW=32,LMUL=4 probably > > static vec4 globalvec[1024]; // vscale ==

On Tue, Oct 1, 2019 at 8:08 AM Robin Kruppe <robin.kruppe at gmail.com> wrote: > > Hello Jacob and Luke, > > First off, even if a dynamically changing vscale was truly necessary > for RVV or SV, this thread would be far too late to raise the question. > That vscale is constant -- that the number of elements in a scalable > vector does not change during program execution

Hi Luke, > was it intentional to leave out both jacob and myself? > [...] > if that was a misunderstanding or an oversight i apologise for raising it. It was definitely not my intention to be non-inclusive, my apologies if that seemed the case! > can i therefore recommend a change, here: > [...] > "This patch adds vscale as a symbolic constant to the IR, similar to >

On 2/5/19 1:27 AM, Philip Reames via llvm-dev wrote: > > On 1/31/19 4:57 PM, Bruce Hoult wrote: >> On Thu, Jan 31, 2019 at 4:05 PM Philip Reames via llvm-dev >> <llvm-dev at lists.llvm.org> wrote: >>> Do such architectures frequently have arithmetic operations on the >>> mask registers?  (i.e. can I reasonable compute a conservative >>> length

On Wed, 2 Oct 2019 at 05:09, Luke Kenneth Casson Leighton <lkcl at lkcl.net> wrote: > > My general feeling on this then is that both RVV and SV should avoid using > vscale. > > In the case of RVV, MVL is a hardware defined constant that is never > *intended* to be known by applications. There's no published detection > mechanism. Loops are supposed to be designed

Hi Everyone, I am wondering how to use RISC-V V (Vector) extension instructions in LLVM IR. In 2019 Kruppe and Espasa gave a talk [1] overviewing the Vector extension and on slide 16 [2] they show LLVM IR samples which use the vector instructions through intrinsic functions, such as: %vl = call i32 @llvm.riscv.vsetvl(i32 %n) At the time of the talk (April 2019) LLVM support for the V

Hi all, At the Barcelona Supercomputing Center, we have been working on an end-to-end vectorizer using scalable vectors for RISC-V Vector extension in context of the EPI Project <https://www.european-processor-initiative.eu/accelerator/>. We earlier shared a demo of our prototype implementation  (https://repo.hca.bsc.es/epic/z/9eYRIF, see below) with the folks involved with LLVM

Hi Robin, responses inline. -Graham > On 11 Jun 2018, at 16:47, Robin Kruppe <robin.kruppe at gmail.com> wrote: > > Hi Graham, > Hi David, > > glad to hear other people are thinking about RVV codegen! > > On 7 June 2018 at 18:10, Graham Hunter <Graham.Hunter at arm.com> wrote: >> >> Hi, >> >>> On 6 Jun 2018, at 17:36, David A.

Thanks @Robin and @Graham for giving some background on scalable vectors and clarifying some of the details! Apologies if I'm repeating things here, but it is probably good to emphasize the conceptually different, but complementary models for scalable vectors: 1. Vectors of unknown, but constant size throughout the program. 2. Vectors of changing size throughout the program. Where (2)

On Fri, Feb 1, 2019 at 1:19 AM Bruce Hoult <brucehoult at sifive.com> wrote: > On Thu, Jan 31, 2019 at 11:53 PM Luke Kenneth Casson Leighton via > llvm-dev <llvm-dev at lists.llvm.org> wrote: > > > > --- > > crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68 > > > > On Thu, Jan 31, 2019 at 10:22 PM Jacob Lifshay

--- crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68 On Thu, Jan 31, 2019 at 10:22 PM Jacob Lifshay <programmerjake at gmail.com> wrote: > > We're in-progress designing a RISC-V extension (http://lists.libre-riscv.org/pipermail/libre-riscv-dev/2019-January/000433.html) that would have variable-length vectors of short vectors (1 to 4): > <VL x <4 x

Hi, > On 6 Jun 2018, at 17:36, David A. Greene <dag at cray.com> wrote: > > Graham Hunter via llvm-dev <llvm-dev at lists.llvm.org> writes: > >>> Ok, now I understand what you're getting at. A ConstantExpr would >>> encapsulate this computation. We alreay have "non-static-constant" >>> values for ConstantExpr like sizeof and

For background on these calls, see <http://lists.llvm.org/pipermail/llvm-dev/2019-September/135087.html>. Reminder: the purpose is to co-ordinate between active contributors. If you have support questions etc then it's best to post to llvm-dev. We have a call every alternate Thursday at 4pm GMT, via <https://meet.google.com/ske-zcog-spp>. We have a shared calendar which may help

For RISC-V V and VE being explicit about %evl is important for performance & correctness and that is what VP does. The get.active.lane.mask intrinsic is used as a hint for the MVE, SVE backends to use hardware tail-predication (the backends reverse engineer that hint by pattern matching for get.active.lane.mask in the mask parameter of "some" masked intrinsics). IMHO, it's more

# Overview and background RISC-V is a free and open instruction set architecture. It is a modular specification, with a range of standard extensions (e.g. floating point, atomics, etc). New standard extensions are developed through RISC-V Foundation working groups. The specifications for such extensions (e.g. vector and bit manipulation) are publicly available, but are still in flux and won't

I built llvm + clang from source, a github clone from today: clang version 11.0.0 (https://github.com/llvm/llvm-project.git 91aa67bf290bc7f877b1b90128284863bc31aa43) I compiled a small program: #include <stdint.h> int main() { uint8_t a = 2; uint8_t b = 5; uint8_t c = a * b; } $ clang -c -target riscv32 -march=rv32imc -g main.c Works fine. The dumped assembly seems to not know

Hi, There is now an RFC for a roadmap to native vector predication support in LLVM and a prototype implementation:   https://reviews.llvm.org/D57504 The prototype demonstrates: -  Predicated vector intrinsics with an explicit mask and vector length parameter on IR level. -  First-class predicated SDNodes on ISel level. Mask and vector length are value operands. -  An incremental strategy

Hi all, On 11/5/20 10:32 AM, Roger Ferrer Ibáñez wrote: Hi Sjoerd, thanks for pointing us to this intrinsic. I see it returns a mask/predicate type. My understanding is that VPred intrinsics have both a vector length operand and a mask operand. It looks to me that a "popcount" of get.active.lane.mask would correspond to the vector length operand. Then additional "control