SPIRVISelLowering.h

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//===-- SPIRVISelLowering.h - SPIR-V DAG Lowering Interface -----*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file defines the interfaces that SPIR-V uses to lower LLVM code into a
// selection DAG.
//
//===----------------------------------------------------------------------===//
 
#ifndef LLVM_LIB_TARGET_SPIRV_SPIRVISELLOWERING_H
#define LLVM_LIB_TARGET_SPIRV_SPIRVISELLOWERING_H
 
#include "SPIRVGlobalRegistry.h"
#include "llvm/CodeGen/TargetLowering.h"
#include <set>
 
namespace llvm {
class SPIRVSubtarget;
 
class SPIRVTargetLowering : public TargetLowering {
  const SPIRVSubtarget &STI;
 
  // Record of already processed machine functions
  mutable std::set<const MachineFunction *> ProcessedMF;
 
public:
  explicit SPIRVTargetLowering(const TargetMachine &TM,
                               const SPIRVSubtarget &ST)
      : TargetLowering(TM), STI(ST) {}
 
  // Stop IRTranslator breaking up FMA instrs to preserve types information.
  bool isFMAFasterThanFMulAndFAdd(const MachineFunction &MF,
                                  EVT) const override {
    return true;
  }
 
  // prevent creation of jump tables
  bool areJTsAllowed(const Function *) const override { return false; }
 
  // This is to prevent sexts of non-i64 vector indices which are generated
  // within general IRTranslator hence type generation for it is omitted.
  unsigned getVectorIdxWidth(const DataLayout &DL) const override { return 32; }
  unsigned getNumRegistersForCallingConv(LLVMContext &Context,
                                         CallingConv::ID CC,
                                         EVT VT) const override;
  MVT getRegisterTypeForCallingConv(LLVMContext &Context, CallingConv::ID CC,
                                    EVT VT) const override;
  bool getTgtMemIntrinsic(IntrinsicInfo &Info, const CallInst &I,
                          MachineFunction &MF,
                          unsigned Intrinsic) const override;
 
  std::pair<unsigned, const TargetRegisterClass *>
  getRegForInlineAsmConstraint(const TargetRegisterInfo *TRI,
                               StringRef Constraint, MVT VT) const override;
  unsigned
  getNumRegisters(LLVMContext &Context, EVT VT,
                  std::optional<MVT> RegisterVT = std::nullopt) const override {
    return 1;
  }
 
  // Call the default implementation and finalize target lowering by inserting
  // extra instructions required to preserve validity of SPIR-V code imposed by
  // the standard.
  void finalizeLowering(MachineFunction &MF) const override;
 
  MVT getPreferredSwitchConditionType(LLVMContext &Context,
                                      EVT ConditionVT) const override {
    return ConditionVT.getSimpleVT();
  }
 
  bool enforcePtrTypeCompatibility(MachineInstr &I, unsigned PtrOpIdx,
                                   unsigned OpIdx) const;
  bool insertLogicalCopyOnResult(MachineInstr &I,
                                 SPIRVType *NewResultType) const;
};
} // namespace llvm
 
#endif // LLVM_LIB_TARGET_SPIRV_SPIRVISELLOWERING_H