[PATCH] D131571: [AArch64][SME] Fix lowering of llvm.aarch64.get.pstatesm()

[Sander de Smalen via Phabricator via llvm-commits]

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A thread may not have access to SME or TPIDR2_EL0, so in order to
safely query PSTATE.SM in a streaming-compatible function, the
code should call `__arm_sme_state()`, as described in the ABI:

  https://github.com/ARM-software/abi-aa/pull/123/commits/c2bb09c4d4ee60a5787baf1ccc7e92e67e4240b7

This means that the value of pstate.sm is:

- 0 if the function is non-streaming.
- 1 if the function has `arm_streaming` or `arm_locally_streaming`.
- evaluated at runtime by a call to __arm_sme_state() otherwise.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D131571

Files:
  llvm/include/llvm/IR/CallingConv.h
  llvm/lib/Target/AArch64/AArch64CallingConvention.td
  llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
  llvm/lib/Target/AArch64/AArch64ISelLowering.h
  llvm/lib/Target/AArch64/AArch64RegisterInfo.cpp
  llvm/test/CodeGen/AArch64/sme-get-pstatesm.ll

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