[all-commits] [llvm/llvm-project] 67d4c9: Add support for (expressing) vscale.

[sdesmalen-arm via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 67d4c9924c1fbfdbfcfa90bf729945eca0a92f86
      https://github.com/llvm/llvm-project/commit/67d4c9924c1fbfdbfcfa90bf729945eca0a92f86
  Author: Sander de Smalen <sander.desmalen at arm.com>
  Date:   2020-01-22 (Wed, 22 Jan 2020)

  Changed paths:
    M llvm/docs/LangRef.rst
    M llvm/include/llvm/CodeGen/ISDOpcodes.h
    M llvm/include/llvm/CodeGen/SelectionDAG.h
    M llvm/include/llvm/IR/Intrinsics.td
    M llvm/include/llvm/IR/PatternMatch.h
    M llvm/include/llvm/Target/TargetSelectionDAG.td
    M llvm/lib/Analysis/ConstantFolding.cpp
    M llvm/lib/CodeGen/CodeGenPrepare.cpp
    M llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
    M llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
    M llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
    M llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
    M llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
    M llvm/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp
    M llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
    M llvm/lib/Target/AArch64/AArch64ISelLowering.h
    M llvm/lib/Target/AArch64/AArch64SVEInstrInfo.td
    A llvm/test/CodeGen/AArch64/sve-vscale.ll

  Log Message:
  -----------
  Add support for (expressing) vscale.

In LLVM IR, vscale can be represented with an intrinsic. For some targets,
this is equivalent to the constexpr:

  getelementptr <vscale x 1 x i8>, <vscale x 1 x i8>* null, i32 1

This can be used to propagate the value in CodeGenPrepare.

In ISel we add a node that can be legalized to one or more
instructions to materialize the runtime vector length.

This patch also adds SVE CodeGen support for VSCALE, which maps this
node to RDVL instructions (for scaled multiples of 16bytes) or CNT[HSD]
instructions (scaled multiples of 2, 4, or 8 bytes, respectively).

Reviewers: rengolin, cameron.mcinally, hfinkel, sebpop, SjoerdMeijer, efriedma, lattner

Reviewed by: efriedma

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D68203