[all-commits] [llvm/llvm-project] 5e82ee: [RISCV][llvm-mca] Use LMUL Instruments to provide ...

[Michael Maitland via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 5e82ee5373211db8522181054800ccd49461d9d8
      https://github.com/llvm/llvm-project/commit/5e82ee5373211db8522181054800ccd49461d9d8
  Author: Michael Maitland <michaeltmaitland at gmail.com>
  Date:   2022-11-15 (Tue, 15 Nov 2022)

  Changed paths:
    M llvm/docs/CommandGuide/llvm-mca.rst
    M llvm/include/llvm/MC/TargetRegistry.h
    M llvm/include/llvm/MCA/CustomBehaviour.h
    M llvm/include/llvm/MCA/InstrBuilder.h
    M llvm/lib/MCA/CustomBehaviour.cpp
    M llvm/lib/MCA/InstrBuilder.cpp
    M llvm/lib/Target/RISCV/CMakeLists.txt
    A llvm/lib/Target/RISCV/MCA/CMakeLists.txt
    A llvm/lib/Target/RISCV/MCA/RISCVCustomBehaviour.cpp
    A llvm/lib/Target/RISCV/MCA/RISCVCustomBehaviour.h
    M llvm/lib/Target/RISCV/RISCVInstrInfoVPseudos.td
    M llvm/tools/llvm-mca/CodeRegion.cpp
    M llvm/tools/llvm-mca/CodeRegion.h
    M llvm/tools/llvm-mca/CodeRegionGenerator.cpp
    M llvm/tools/llvm-mca/CodeRegionGenerator.h
    M llvm/tools/llvm-mca/llvm-mca.cpp
    M llvm/unittests/tools/llvm-mca/MCATestBase.cpp
    M llvm/unittests/tools/llvm-mca/X86/TestIncrementalMCA.cpp

  Log Message:
  -----------
  [RISCV][llvm-mca] Use LMUL Instruments to provide more accurate reports on RISCV

On x86 and AArch, SIMD instructions encode all of the scheduling information in the instruction
itself. For example, VADD.I16 q0, q1, q2 is a neon instruction that operates on 16-bit integer
elements stored in 128-bit Q registers, which leads to eight 16-bit lanes in parallel. This kind
of information impacts how the instruction takes to execute and what dependencies this may cause.

On RISCV however, the data that impacts scheduling is encoded in CSR registers such as vtype or
vl, in addition with the instruction itself. But MCA does not track or use the data in these
registers. This patch fixes this problem by introducing Instruments into MCA.

* Replace `CodeRegions` with `AnalysisRegions`
* Add `Instrument` and `InstrumentManager`
* Add `InstrumentRegions`
* Add RISCV Instrument and `InstrumentManager`
* Parse `Instruments` in driver
* Use instruments to override schedule class
* RISCV use lmul instrument to override schedule class
* Fix unit tests to pass empty instruments
* Add -ignore-im clopt to disable this change

Differential Revision: https://reviews.llvm.org/D137440