Re: [PATCH V5 0/3] RISC-V: Add an experimental vector calling convention

[Kito Cheng <kito.cheng@gmail.com>]

Thanks for fixing the issue! I guess I could find time tonight to do
the final round review and test :P then we could land this patch this
week.

On Tue, Sep 5, 2023 at 3:45 PM Lehua Ding <lehua.ding@rivai.ai> wrote:
>
> V5 change: Rebase and fix vsetvl testcase fail by change
> `(unspec [...] UNSPEC_CALLEE_CC)` to `(use (unspec [...] UNSPEC_CALLEE_CC))`.
> This change makes single_set function re-think call_insn as a
> single set pattern.
>
> Hi RISC-V folks,
>
> This patch implement the proposal of RISC-V vector calling convention[1] and
> this feature can be enabled by `--param=riscv-vector-abi` option. Currently,
> all vector type arguments and return values are pass by reference. With this
> patch, these arguments and return values can pass through vector registers.
> Currently only vector types defined in the RISC-V Vector Extension Intrinsic Document[2]
> are supported. GNU-ext vector types are unsupported for now since the
> corresponding proposal was not presented.
>
> The proposal introduce a new calling convention variant, functions which follow
> this variant need follow the bellow vector register convention.
>
> | Name    | ABI Mnemonic | Meaning                      | Preserved across calls?
> =================================================================================
> | v0      |              | Argument register            | No
> | v1-v7   |              | Callee-saved registers       | Yes
> | v8-v23  |              | Argument registers           | No
> | v24-v31 |              | Callee-saved registers       | Yes
>
> If a functions follow this vector calling convention, then the function symbole
> must be annotated with .variant_cc directive[3] (used to indicate that it is a
> calling convention variant).
>
> This implementation split into three parts, each part corresponds to a sub-patch.
>
> - Part-1: Select suitable vector regsiters for vector type arguments and return
>   values according to the proposal.
> - Part-2: Allocate frame area for callee-saved vector registers and save/restore
>   them in prologue and epilogue.
> - Part-3: Generate .variant_cc directive for vector function in assembly code.
>
> [1] https://github.com/riscv-non-isa/riscv-elf-psabi-doc/pull/389
> [2] https://github.com/riscv-non-isa/rvv-intrinsic-doc/blob/master/rvv-intrinsic-rfc.md#type-system
> [3] https://github.com/riscv-non-isa/riscv-asm-manual/blob/master/riscv-asm.md#pseudo-ops
>
> Best,
> Lehua
>
> Lehua Ding (3):
>   RISC-V: Part-1: Select suitable vector registers for vector type args
>     and returns
>   RISC-V: Part-2: Save/Restore vector registers which need to be
>     preversed
>   RISC-V: Part-3: Output .variant_cc directive for vector function
>
>  gcc/config/riscv/riscv-protos.h               |   4 +
>  gcc/config/riscv/riscv-sr.cc                  |   8 +-
>  gcc/config/riscv/riscv-vector-builtins.cc     |  10 +
>  gcc/config/riscv/riscv.cc                     | 484 ++++++++++++++++--
>  gcc/config/riscv/riscv.h                      |  43 ++
>  gcc/config/riscv/riscv.md                     |  51 +-
>  gcc/config/riscv/riscv.opt                    |   5 +
>  .../riscv/rvv/base/abi-call-args-1-run.c      | 127 +++++
>  .../riscv/rvv/base/abi-call-args-1.c          | 197 +++++++
>  .../riscv/rvv/base/abi-call-args-2-run.c      |  34 ++
>  .../riscv/rvv/base/abi-call-args-2.c          |  27 +
>  .../riscv/rvv/base/abi-call-args-3-run.c      | 260 ++++++++++
>  .../riscv/rvv/base/abi-call-args-3.c          | 116 +++++
>  .../riscv/rvv/base/abi-call-args-4-run.c      | 145 ++++++
>  .../riscv/rvv/base/abi-call-args-4.c          | 111 ++++
>  .../riscv/rvv/base/abi-call-error-1.c         |  11 +
>  .../riscv/rvv/base/abi-call-return-run.c      | 127 +++++
>  .../riscv/rvv/base/abi-call-return.c          | 197 +++++++
>  .../riscv/rvv/base/abi-call-variant_cc.c      |  39 ++
>  .../rvv/base/abi-callee-saved-1-fixed-1.c     |  86 ++++
>  .../rvv/base/abi-callee-saved-1-fixed-2.c     |  86 ++++
>  .../base/abi-callee-saved-1-save-restore.c    |  85 +++
>  .../riscv/rvv/base/abi-callee-saved-1-zcmp.c  |  85 +++
>  .../riscv/rvv/base/abi-callee-saved-1.c       |  88 ++++
>  .../base/abi-callee-saved-2-save-restore.c    | 108 ++++
>  .../riscv/rvv/base/abi-callee-saved-2-zcmp.c  | 107 ++++
>  .../riscv/rvv/base/abi-callee-saved-2.c       | 117 +++++
>  27 files changed, 2709 insertions(+), 49 deletions(-)
>  create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/base/abi-call-args-1-run.c
>  create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/base/abi-call-args-1.c
>  create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/base/abi-call-args-2-run.c
>  create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/base/abi-call-args-2.c
>  create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/base/abi-call-args-3-run.c
>  create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/base/abi-call-args-3.c
>  create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/base/abi-call-args-4-run.c
>  create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/base/abi-call-args-4.c
>  create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/base/abi-call-error-1.c
>  create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/base/abi-call-return-run.c
>  create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/base/abi-call-return.c
>  create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/base/abi-call-variant_cc.c
>  create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/base/abi-callee-saved-1-fixed-1.c
>  create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/base/abi-callee-saved-1-fixed-2.c
>  create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/base/abi-callee-saved-1-save-restore.c
>  create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/base/abi-callee-saved-1-zcmp.c
>  create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/base/abi-callee-saved-1.c
>  create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/base/abi-callee-saved-2-save-restore.c
>  create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/base/abi-callee-saved-2-zcmp.c
>  create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/base/abi-callee-saved-2.c
>
> --
> 2.36.3
>