[all-commits] [llvm/llvm-project] c88f27: [LoongArch] Add back SDNPSideEffect properties to ...

[WÁNG Xuěruì via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: c88f27fe1e449158a450d54b8504b2ff9ca490b4
      https://github.com/llvm/llvm-project/commit/c88f27fe1e449158a450d54b8504b2ff9ca490b4
  Author: WANG Xuerui <git at xen0n.name>
  Date:   2023-06-28 (Wed, 28 Jun 2023)

  Changed paths:
    M llvm/lib/Target/LoongArch/LoongArchInstrInfo.td
    A llvm/test/CodeGen/LoongArch/intrinsic-csr-side-effects.ll
    A llvm/test/CodeGen/LoongArch/intrinsic-iocsr-side-effects.ll
    M llvm/test/CodeGen/LoongArch/intrinsic-la64.ll
    M llvm/test/CodeGen/LoongArch/intrinsic.ll

  Log Message:
  -----------
  [LoongArch] Add back SDNPSideEffect properties to CSR and IOCSR read ops

In general, CSR and IOCSR reads should be treated as volatile because:

* there may well be intervening writes between seemingly common
  expressions;
* the stateful entity behind a given (IO)CSR may well be volatile.

Confirmed to fix broken Clang Linux/LoongArch builds (dying when a
userspace process tries to use FPU, panicking when that process happens
to be PID 1) with this patch.

Fixes: https://github.com/llvm/llvm-project/issues/63549
Fixes: 2efdacf74c54 ("[LoongArch] Add missing chains and remove unnecessary `SDNPSideEffect` property for some intrinsic nodes")

Reviewed By: SixWeining, hev

Differential Revision: https://reviews.llvm.org/D153865