[PATCH v3 0/6] RISC-V: autovec: Add auto-vectorization support

[Michael Collison <collison@rivosinc.com>]

This series of patches adds foundational support for RISC-V auto-vectorization support. These patches are based on the current upstream rvv vector intrinsic support and is not a new implementation. Most of the implementation consists of adding the new vector cost model, the autovectorization patterns themselves and target hooks. This implementation only provides support for integer addition and subtraction as a proof of concept. This patch set should not be construed to be feature complete. Based on conversations with the community these patches are intended to lay the groundwork for feature completion and collaboration within the RISC-V community.

These patches are largely based off the work of Juzhe Zhong (juzhe.zhong@rivai.ai<mailto:juzhe.zhong@rivai.ai>) of RiVAI. More specifically the rvv-next branch at: https://github.com/riscv-collab/riscv-gcc.git <https://github.com/riscv-collab/riscv-gcc.git>is the foundation of this patch set. 

As discussed on this list, if these patches are approved they will be merged into a "auto-vectorization" branch once gcc-13 branches for release. There are two known issues related to crashes (assert failures) associated with tree vectorization; one of which I have sent a patch for and have received feedback. 

Changes in v3:

- Removed the cost model and cost hooks based on feedback from Richard Biener
- Used RVV_VUNDEF macro to fix failing patterns

Changes in v2 

- Updated ChangeLog entry to include RiVAI contributions 
- Fixed ChangeLog email formatting 
- Fixed gnu formatting issues in the code 

Michael Collison (6):
  RISC-V: Add new predicates and function prototypes
  RISC-V: autovec: Export policy functions to global scope
  RISC-V:autovec: Add auto-vectorization support functions
  RISC-V:autovec: Add target vectorization hooks
  RISC-V:autovec: Add autovectorization patterns for add & sub
  RISC-V:autovec: Add autovectorization tests for add & sub

 gcc/config/riscv/predicates.md                |  13 ++
 gcc/config/riscv/riscv-opts.h                 |  40 ++++
 gcc/config/riscv/riscv-protos.h               |  15 ++
 gcc/config/riscv/riscv-v.cc                   | 178 +++++++++++++++++-
 gcc/config/riscv/riscv-vector-builtins.cc     |   4 +-
 gcc/config/riscv/riscv-vector-builtins.h      |   2 +
 gcc/config/riscv/riscv.cc                     | 156 +++++++++++++++
 gcc/config/riscv/riscv.md                     |   1 +
 gcc/config/riscv/riscv.opt                    |  20 ++
 gcc/config/riscv/vector-auto.md               | 172 +++++++++++++++++
 gcc/config/riscv/vector-iterators.md          |   2 +
 gcc/config/riscv/vector.md                    |   4 +-
 .../riscv/rvv/autovec/loop-add-rv32.c         |  24 +++
 .../gcc.target/riscv/rvv/autovec/loop-add.c   |  24 +++
 .../riscv/rvv/autovec/loop-sub-rv32.c         |  24 +++
 .../gcc.target/riscv/rvv/autovec/loop-sub.c   |  24 +++
 16 files changed, 698 insertions(+), 5 deletions(-)
 create mode 100644 gcc/config/riscv/vector-auto.md
 create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/autovec/loop-add-rv32.c
 create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/autovec/loop-add.c
 create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/autovec/loop-sub-rv32.c
 create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/autovec/loop-sub.c

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2.34.1