[all-commits] [llvm/llvm-project] 3a6022: [RISCV] Add SchedRead for Merge operands on MASK P...

[Michael Maitland via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 3a602236c7782e77f4490e15ea5b4fd8fa2b5d9e
      https://github.com/llvm/llvm-project/commit/3a602236c7782e77f4490e15ea5b4fd8fa2b5d9e
  Author: Michael Maitland <michaeltmaitland at gmail.com>
  Date:   2023-07-26 (Wed, 26 Jul 2023)

  Changed paths:
    M llvm/lib/Target/RISCV/RISCVInstrInfoV.td
    M llvm/lib/Target/RISCV/RISCVInstrInfoXTHead.td
    M llvm/lib/Target/RISCV/RISCVSchedSiFive7.td
    M llvm/lib/Target/RISCV/RISCVScheduleV.td

  Log Message:
  -----------
  [RISCV] Add SchedRead for Merge operands on MASK Pseudos

For Pseudos that end in _MASK or should be forceMasked,
which means that in the case that the instruction should be
mask undisturbed the destination register must be read to
determine the undisturbed values. This patch adds a SchedRead
that gets passed to MASK pseudos to represent this extra read that
must occur.

A future patch should do something similiar for when a pseudo is TU,
since those instructions must also read their destination to preserve
undisturbed-ness.

Differential Revision: https://reviews.llvm.org/D155654