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//===-- NVPTXTargetTransformInfo.h - NVPTX specific TTI ---------*- C++ -*-===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
/// \file
/// This file a TargetTransformInfo::Concept conforming object specific to the
/// NVPTX target machine. It uses the target's detailed information to
/// provide more precise answers to certain TTI queries, while letting the
/// target independent and default TTI implementations handle the rest.
#include "NVPTXTargetMachine.h"
#include "MCTargetDesc/NVPTXBaseInfo.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/CodeGen/BasicTTIImpl.h"
#include "llvm/CodeGen/TargetLowering.h"
#include <optional>
namespace llvm {
class NVPTXTTIImpl : public BasicTTIImplBase<NVPTXTTIImpl> {
typedef BasicTTIImplBase<NVPTXTTIImpl> BaseT;
typedef TargetTransformInfo TTI;
friend BaseT;
const NVPTXSubtarget *ST;
const NVPTXTargetLowering *TLI;
const NVPTXSubtarget *getST() const { return ST; };
const NVPTXTargetLowering *getTLI() const { return TLI; };
explicit NVPTXTTIImpl(const NVPTXTargetMachine *TM, const Function &F)
: BaseT(TM, F.getParent()->getDataLayout()), ST(TM->getSubtargetImpl()),
TLI(ST->getTargetLowering()) {}
bool hasBranchDivergence(const Function *F = nullptr) { return true; }
bool isSourceOfDivergence(const Value *V);
unsigned getFlatAddressSpace() const {
return AddressSpace::ADDRESS_SPACE_GENERIC;
bool canHaveNonUndefGlobalInitializerInAddressSpace(unsigned AS) const {
return AS != AddressSpace::ADDRESS_SPACE_SHARED &&
std::optional<Instruction *> instCombineIntrinsic(InstCombiner &IC,
IntrinsicInst &II) const;
// Loads and stores can be vectorized if the alignment is at least as big as
// the load/store we want to vectorize.
bool isLegalToVectorizeLoadChain(unsigned ChainSizeInBytes, Align Alignment,
unsigned AddrSpace) const {
return Alignment >= ChainSizeInBytes;
bool isLegalToVectorizeStoreChain(unsigned ChainSizeInBytes, Align Alignment,
unsigned AddrSpace) const {
return isLegalToVectorizeLoadChain(ChainSizeInBytes, Alignment, AddrSpace);
// NVPTX has infinite registers of all kinds, but the actual machine doesn't.
// We conservatively return 1 here which is just enough to enable the
// vectorizers but disables heuristics based on the number of registers.
// FIXME: Return a more reasonable number, while keeping an eye on
// LoopVectorizer's unrolling heuristics.
unsigned getNumberOfRegisters(bool Vector) const { return 1; }
// Only <2 x half> should be vectorized, so always return 32 for the vector
// register size.
TypeSize getRegisterBitWidth(TargetTransformInfo::RegisterKind K) const {
return TypeSize::getFixed(32);
unsigned getMinVectorRegisterBitWidth() const { return 32; }
// We don't want to prevent inlining because of target-cpu and -features
// attributes that were added to newer versions of LLVM/Clang: There are
// no incompatible functions in PTX, ptxas will throw errors in such cases.
bool areInlineCompatible(const Function *Caller,
const Function *Callee) const {
return true;
// Increase the inlining cost threshold by a factor of 11, reflecting that
// calls are particularly expensive in NVPTX.
unsigned getInliningThresholdMultiplier() const { return 11; }
InstructionCost getArithmeticInstrCost(
unsigned Opcode, Type *Ty, TTI::TargetCostKind CostKind,
TTI::OperandValueInfo Op1Info = {TTI::OK_AnyValue, TTI::OP_None},
TTI::OperandValueInfo Op2Info = {TTI::OK_AnyValue, TTI::OP_None},
ArrayRef<const Value *> Args = ArrayRef<const Value *>(),
const Instruction *CxtI = nullptr);
void getUnrollingPreferences(Loop *L, ScalarEvolution &SE,
TTI::UnrollingPreferences &UP,
OptimizationRemarkEmitter *ORE);
void getPeelingPreferences(Loop *L, ScalarEvolution &SE,
TTI::PeelingPreferences &PP);
bool hasVolatileVariant(Instruction *I, unsigned AddrSpace) {
// Volatile loads/stores are only supported for shared and global address
// spaces, or for generic AS that maps to them.
if (!(AddrSpace == llvm::ADDRESS_SPACE_GENERIC ||
AddrSpace == llvm::ADDRESS_SPACE_GLOBAL ||
AddrSpace == llvm::ADDRESS_SPACE_SHARED))
return false;
return false;
case Instruction::Load:
case Instruction::Store:
return true;
} // end namespace llvm