[PATCH 0/1] [V2] RISC-V: support Zcmp extension

[Fei Gao <gaofei@eswincomputing.com>]

Before implementing Zcmp, I did some optimizations and restructures to save-restore.
https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=a5b2a3bff8152aa34408d8ce40add82f4d22ff87
https://gcc.gnu.org/git/?p=gcc.git;a=commitdiff;h=60524be1e3929d83e15fceac6e2aa053c8a6fb20
https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=a782346757c54a5a3cfb9f416a7ebe3554a617d7

Then Zcmp can share the same logic as save-restore in stack allocation: pre-allocation
by cm.push, step 1 and step 2.

please be noted cm.push pushes ra, s0-s11 in reverse order than what save-restore does.
So adaption has been done in .cfi directives in my patch. A discussion be found here:
https://github.com/riscv/riscv-code-size-reduction/issues/182

Weeks before, Jiawei also posted Zcmp in https://gcc.gnu.org/pipermail/gcc-patches/2023-April/615287.html.
[PATCH 0/5] RISC-V: Support ZC* extensions.   Jiawei
[PATCH 1/5] RISC-V: Minimal support for ZC extensions.   Jiawei
[PATCH 2/5] RISC-V: Enable compressible features when use ZC* extensions.   Jiawei
[PATCH 3/5] RISC-V: Add ZC* test for march args being passed.   Jiawei
[PATCH 4/5] RISC-V: Add Zcmp extension supports.   Jiawei
[PATCH 5/5] RISC-V: Add ZCMP push/pop testcases.   Jiawei

I tested his codes and observed some issues in [PATCH 4/5],
see https://www.mail-archive.com/gcc-patches@gcc.gnu.org/msg306921.html for details.
So I plan to post my codes as an alternative of Jiawei's [PATCH 4/5].

My Zcmp switch codes are almost same as Jiawei's.
So i avoid repeating them in my patch series.
Please pick up Jiawei's [PATCH 1/5] before picking up my patch series.

Fei Gao (1):
  [RISC-V] support  cm.push cm.pop cm.popret in zcmp

 gcc/config/riscv/predicates.md                |  148 +++
 gcc/config/riscv/riscv-protos.h               |    2 +
 gcc/config/riscv/riscv.cc                     |  477 +++++++-
 gcc/config/riscv/riscv.h                      |   23 +
 gcc/config/riscv/riscv.md                     |    2 +
 gcc/config/riscv/zc.md                        | 1042 +++++++++++++++++
 gcc/testsuite/gcc.target/riscv/rv32e_zcmp.c   |  239 ++++
 gcc/testsuite/gcc.target/riscv/rv32i_zcmp.c   |  239 ++++
 .../gcc.target/riscv/zcmp_stack_alignment.c   |   23 +
 9 files changed, 2155 insertions(+), 40 deletions(-)
 create mode 100644 gcc/config/riscv/zc.md
 create mode 100644 gcc/testsuite/gcc.target/riscv/rv32e_zcmp.c
 create mode 100644 gcc/testsuite/gcc.target/riscv/rv32i_zcmp.c
 create mode 100644 gcc/testsuite/gcc.target/riscv/zcmp_stack_alignment.c

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2.17.1