NVPTXTargetTransformInfo.cpp revision 277323 
1//===-- NVPTXTargetTransformInfo.cpp - NVPTX specific TTI pass ---------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// \file
11// This file implements a TargetTransformInfo analysis pass specific to the
12// NVPTX target machine. It uses the target's detailed information to provide
13// more precise answers to certain TTI queries, while letting the target
14// independent and default TTI implementations handle the rest.
15//
16//===----------------------------------------------------------------------===//
17
18#include "NVPTXTargetMachine.h"
19#include "llvm/Analysis/LoopInfo.h"
20#include "llvm/Analysis/TargetTransformInfo.h"
21#include "llvm/Analysis/ValueTracking.h"
22#include "llvm/Support/Debug.h"
23#include "llvm/Target/CostTable.h"
24#include "llvm/Target/TargetLowering.h"
25using namespace llvm;
26
27#define DEBUG_TYPE "NVPTXtti"
28
29// Declare the pass initialization routine locally as target-specific passes
30// don't have a target-wide initialization entry point, and so we rely on the
31// pass constructor initialization.
32namespace llvm {
33void initializeNVPTXTTIPass(PassRegistry &);
34}
35
36namespace {
37
38class NVPTXTTI final : public ImmutablePass, public TargetTransformInfo {
39  const NVPTXTargetLowering *TLI;
40public:
41  NVPTXTTI() : ImmutablePass(ID), TLI(nullptr) {
42    llvm_unreachable("This pass cannot be directly constructed");
43  }
44
45  NVPTXTTI(const NVPTXTargetMachine *TM)
46      : ImmutablePass(ID), TLI(TM->getSubtargetImpl()->getTargetLowering()) {
47    initializeNVPTXTTIPass(*PassRegistry::getPassRegistry());
48  }
49
50  void initializePass() override { pushTTIStack(this); }
51
52  void getAnalysisUsage(AnalysisUsage &AU) const override {
53    TargetTransformInfo::getAnalysisUsage(AU);
54  }
55
56  /// Pass identification.
57  static char ID;
58
59  /// Provide necessary pointer adjustments for the two base classes.
60  void *getAdjustedAnalysisPointer(const void *ID) override {
61    if (ID == &TargetTransformInfo::ID)
62      return (TargetTransformInfo *)this;
63    return this;
64  }
65
66  bool hasBranchDivergence() const override;
67
68  unsigned getArithmeticInstrCost(
69      unsigned Opcode, Type *Ty, OperandValueKind Opd1Info = OK_AnyValue,
70      OperandValueKind Opd2Info = OK_AnyValue,
71      OperandValueProperties Opd1PropInfo = OP_None,
72      OperandValueProperties Opd2PropInfo = OP_None) const override;
73};
74
75} // end anonymous namespace
76
77INITIALIZE_AG_PASS(NVPTXTTI, TargetTransformInfo, "NVPTXtti",
78                   "NVPTX Target Transform Info", true, true, false)
79char NVPTXTTI::ID = 0;
80
81ImmutablePass *
82llvm::createNVPTXTargetTransformInfoPass(const NVPTXTargetMachine *TM) {
83  return new NVPTXTTI(TM);
84}
85
86bool NVPTXTTI::hasBranchDivergence() const { return true; }
87
88unsigned NVPTXTTI::getArithmeticInstrCost(
89    unsigned Opcode, Type *Ty, OperandValueKind Opd1Info,
90    OperandValueKind Opd2Info, OperandValueProperties Opd1PropInfo,
91    OperandValueProperties Opd2PropInfo) const {
92  // Legalize the type.
93  std::pair<unsigned, MVT> LT = TLI->getTypeLegalizationCost(Ty);
94
95  int ISD = TLI->InstructionOpcodeToISD(Opcode);
96
97  switch (ISD) {
98  default:
99    return TargetTransformInfo::getArithmeticInstrCost(
100        Opcode, Ty, Opd1Info, Opd2Info, Opd1PropInfo, Opd2PropInfo);
101  case ISD::ADD:
102  case ISD::MUL:
103  case ISD::XOR:
104  case ISD::OR:
105  case ISD::AND:
106    // The machine code (SASS) simulates an i64 with two i32. Therefore, we
107    // estimate that arithmetic operations on i64 are twice as expensive as
108    // those on types that can fit into one machine register.
109    if (LT.second.SimpleTy == MVT::i64)
110      return 2 * LT.first;
111    // Delegate other cases to the basic TTI.
112    return TargetTransformInfo::getArithmeticInstrCost(
113        Opcode, Ty, Opd1Info, Opd2Info, Opd1PropInfo, Opd2PropInfo);
114  }
115}
116