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* [PATCH 0/3] RISC-V: Add an experimental vector calling convention
@ 2023-07-20  9:01 Lehua Ding
  2023-07-20  9:01 ` [PATCH 1/3] RISC-V: Part-1: Select suitable vector registers for vector type args and returns Lehua Ding
                   ` (2 more replies)
  0 siblings, 3 replies; 8+ messages in thread
From: Lehua Ding @ 2023-07-20  9:01 UTC (permalink / raw)
  To: gcc-patches; +Cc: juzhe.zhong, rdapp.gcc, kito.cheng, palmer, jeffreyalaw

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.

Best,
Lehua

[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

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                  |  12 +-
 gcc/config/riscv/riscv-vector-builtins.cc     |  10 +
 gcc/config/riscv/riscv.cc                     | 510 ++++++++++++++++--
 gcc/config/riscv/riscv.h                      |  40 ++
 gcc/config/riscv/riscv.md                     |  43 +-
 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     |  85 +++
 .../rvv/base/abi-callee-saved-1-fixed-2.c     |  85 +++
 .../riscv/rvv/base/abi-callee-saved-1.c       |  87 +++
 .../riscv/rvv/base/abi-callee-saved-2.c       | 117 ++++
 23 files changed, 2327 insertions(+), 62 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.c
 create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/base/abi-callee-saved-2.c

-- 
2.36.3


^ permalink raw reply	[flat|nested] 8+ messages in thread
* Re: [PATCH 2/3] RISC-V: Part-2: Save/Restore vector registers which need to be preversed
@ 2023-08-07  7:31 Lehua Ding
  0 siblings, 0 replies; 8+ messages in thread
From: Lehua Ding @ 2023-08-07  7:31 UTC (permalink / raw)
  To: Kito Cheng; +Cc: gcc-patches, juzhe.zhong, rdapp.gcc, palmer, jeffreyalaw

[-- Attachment #1: Type: text/plain, Size: 1109 bytes --]

Hi Kito,

> > +machine_mode m1_mode = TARGET_VECTOR_ELEN_64
> > +? (TARGET_MIN_VLEN >= 128 ? VNx2DImode : VNx1DImode) 
> > +: VNx1SImode;

> This should update since JuZhe has update the mode system :P

Yes, thanks reminder.

> > @@ -5907,7 +6057,7 @@ riscv_expand_epilogue (int style) 
> > Start off by assuming that no registers need to be restored.*/ 
> >struct riscv_frame_info *frame = &cfun->machine->frame; 
> >unsigned mask = frame->mask; 
> > -HOST_WIDE_INT step2 = 0; 
> > +poly_int64 step2 = 0; 

> I saw we check `step2.to_constant () 
> 0` later, does it mean step2 is 
> always a scalar rather than a poly number? 
> If so, I would suggest keeping HOST_WIDE_INT if possible.
step2 will be reduced by `riscv_for_each_saved_v_reg (step2, riscv_restore_reg, false);`
before `step2.to_constant () > 0`. After `riscv_for_each_saved_v_reg`,
the step2 must be a constant. So step2 may be a poly number if there are any
length agnostic vector registers that need to be saved.

Best,
Lehua

^ permalink raw reply	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2023-08-10  7:08 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-07-20  9:01 [PATCH 0/3] RISC-V: Add an experimental vector calling convention Lehua Ding
2023-07-20  9:01 ` [PATCH 1/3] RISC-V: Part-1: Select suitable vector registers for vector type args and returns Lehua Ding
2023-08-07  8:51   ` Kito Cheng
2023-08-10  7:08     ` Lehua Ding
2023-07-20  9:01 ` [PATCH 2/3] RISC-V: Part-2: Save/Restore vector registers which need to be preversed Lehua Ding
2023-08-07  6:53   ` Kito Cheng
2023-07-20  9:01 ` [PATCH 3/3] RISC-V: Part-3: Output .variant_cc directive for vector function Lehua Ding
2023-08-07  7:31 [PATCH 2/3] RISC-V: Part-2: Save/Restore vector registers which need to be preversed Lehua Ding

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