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[0/3,RFC] RISC-V: Associate typed insns to dfa reservation

Message ID 20231215185328.794425-1-ewlu@rivosinc.com
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Series RISC-V: Associate typed insns to dfa reservation | expand

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Edwin Lu Dec. 15, 2023, 6:53 p.m. UTC 
This series is a prototype for adding all typed instructions to a dfa 
scheduling pipeline.

I've been working on adding insn reservations for all typed instructions
to ensure all instructions are part of a dfa pipeline. I don't have a good 
understanding of vector instruction latency, so I have been struggling
with what I should do for those. 

As of right now, I have copied the insn reservations from generic-ooo.md 
for vector instructions into the generic.md and sifive-7.md files. This 
prevents ICEs from enabling the assert but introduces numerous scan
dump failures (when tested in linux rv64gcv and rv64gc_zba_zbb_zbc_zbs).

Currently, only patch 1/3 RISC-V: Add non-vector types to pipelines does
not introduce regressions (when tested against linux rv32/64 gc/gcv
on rocket).  I hope that the locations I added the insn types make sense. 
Please let me know if they should change.

The final patch enables the assert for insn_has_dfa_reservation. 

I tested the full patch series on both rocket and sifive-7-series. The 
series does introduce additional scan dump failures compared to their
respective baselines, however, I'm not sure how many failures were
due to the patch vs incorrect modeling assumptions. I created
PR113035 which has the full testsuite failures I saw (without the patches
applied).

Edwin Lu (3):
  RISC-V: Add non-vector types to pipelines
  RISC-V: Add vector related reservations
  RISC-V: Enable assert for insn_has_dfa_reservation

 gcc/config/riscv/generic-ooo.md |  31 ++++----
 gcc/config/riscv/generic.md     | 131 +++++++++++++++++++++++++++++++-
 gcc/config/riscv/riscv.cc       |   2 -
 gcc/config/riscv/sifive-7.md    | 130 ++++++++++++++++++++++++++++++-
 4 files changed, 271 insertions(+), 23 deletions(-)