1 //===- llvm/unittest/CodeGen/AArch64SelectionDAGTest.cpp -------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "llvm/CodeGen/SelectionDAG.h"
10 #include "llvm/Analysis/OptimizationRemarkEmitter.h"
11 #include "llvm/AsmParser/Parser.h"
12 #include "llvm/CodeGen/MachineModuleInfo.h"
13 #include "llvm/CodeGen/TargetLowering.h"
14 #include "llvm/Support/SourceMgr.h"
15 #include "llvm/Support/TargetRegistry.h"
16 #include "llvm/Support/TargetSelect.h"
17 #include "llvm/Target/TargetMachine.h"
18 #include "gtest/gtest.h"
19 
20 using namespace llvm;
21 
22 namespace {
23 
24 class AArch64SelectionDAGTest : public testing::Test {
25 protected:
26   static void SetUpTestCase() {
27     InitializeAllTargets();
28     InitializeAllTargetMCs();
29   }
30 
31   void SetUp() override {
32     StringRef Assembly = "define void @f() { ret void }";
33 
34     Triple TargetTriple("aarch64--");
35     std::string Error;
36     const Target *T = TargetRegistry::lookupTarget("", TargetTriple, Error);
37     // FIXME: These tests do not depend on AArch64 specifically, but we have to
38     // initialize a target. A skeleton Target for unittests would allow us to
39     // always run these tests.
40     if (!T)
41       return;
42 
43     TargetOptions Options;
44     TM = std::unique_ptr<LLVMTargetMachine>(static_cast<LLVMTargetMachine*>(
45         T->createTargetMachine("AArch64", "", "", Options, None, None,
46                                CodeGenOpt::Aggressive)));
47     if (!TM)
48       return;
49 
50     SMDiagnostic SMError;
51     M = parseAssemblyString(Assembly, SMError, Context);
52     if (!M)
53       report_fatal_error(SMError.getMessage());
54     M->setDataLayout(TM->createDataLayout());
55 
56     F = M->getFunction("f");
57     if (!F)
58       report_fatal_error("F?");
59 
60     MachineModuleInfo MMI(TM.get());
61 
62     MF = std::make_unique<MachineFunction>(*F, *TM, *TM->getSubtargetImpl(*F), 0,
63                                       MMI);
64 
65     DAG = std::make_unique<SelectionDAG>(*TM, CodeGenOpt::None);
66     if (!DAG)
67       report_fatal_error("DAG?");
68     OptimizationRemarkEmitter ORE(F);
69     DAG->init(*MF, ORE, nullptr, nullptr, nullptr);
70   }
71 
72   LLVMContext Context;
73   std::unique_ptr<LLVMTargetMachine> TM;
74   std::unique_ptr<Module> M;
75   Function *F;
76   std::unique_ptr<MachineFunction> MF;
77   std::unique_ptr<SelectionDAG> DAG;
78 };
79 
80 TEST_F(AArch64SelectionDAGTest, computeKnownBits_ZERO_EXTEND_VECTOR_INREG) {
81   if (!TM)
82     return;
83   SDLoc Loc;
84   auto Int8VT = EVT::getIntegerVT(Context, 8);
85   auto Int16VT = EVT::getIntegerVT(Context, 16);
86   auto InVecVT = EVT::getVectorVT(Context, Int8VT, 4);
87   auto OutVecVT = EVT::getVectorVT(Context, Int16VT, 2);
88   auto InVec = DAG->getConstant(0, Loc, InVecVT);
89   auto Op = DAG->getNode(ISD::ZERO_EXTEND_VECTOR_INREG, Loc, OutVecVT, InVec);
90   auto DemandedElts = APInt(2, 3);
91   KnownBits Known = DAG->computeKnownBits(Op, DemandedElts);
92   EXPECT_TRUE(Known.isZero());
93 }
94 
95 TEST_F(AArch64SelectionDAGTest, computeKnownBits_EXTRACT_SUBVECTOR) {
96   if (!TM)
97     return;
98   SDLoc Loc;
99   auto IntVT = EVT::getIntegerVT(Context, 8);
100   auto VecVT = EVT::getVectorVT(Context, IntVT, 3);
101   auto IdxVT = EVT::getIntegerVT(Context, 64);
102   auto Vec = DAG->getConstant(0, Loc, VecVT);
103   auto ZeroIdx = DAG->getConstant(0, Loc, IdxVT);
104   auto Op = DAG->getNode(ISD::EXTRACT_SUBVECTOR, Loc, VecVT, Vec, ZeroIdx);
105   auto DemandedElts = APInt(3, 7);
106   KnownBits Known = DAG->computeKnownBits(Op, DemandedElts);
107   EXPECT_TRUE(Known.isZero());
108 }
109 
110 TEST_F(AArch64SelectionDAGTest, ComputeNumSignBits_SIGN_EXTEND_VECTOR_INREG) {
111   if (!TM)
112     return;
113   SDLoc Loc;
114   auto Int8VT = EVT::getIntegerVT(Context, 8);
115   auto Int16VT = EVT::getIntegerVT(Context, 16);
116   auto InVecVT = EVT::getVectorVT(Context, Int8VT, 4);
117   auto OutVecVT = EVT::getVectorVT(Context, Int16VT, 2);
118   auto InVec = DAG->getConstant(1, Loc, InVecVT);
119   auto Op = DAG->getNode(ISD::SIGN_EXTEND_VECTOR_INREG, Loc, OutVecVT, InVec);
120   auto DemandedElts = APInt(2, 3);
121   EXPECT_EQ(DAG->ComputeNumSignBits(Op, DemandedElts), 15u);
122 }
123 
124 TEST_F(AArch64SelectionDAGTest, ComputeNumSignBits_EXTRACT_SUBVECTOR) {
125   if (!TM)
126     return;
127   SDLoc Loc;
128   auto IntVT = EVT::getIntegerVT(Context, 8);
129   auto VecVT = EVT::getVectorVT(Context, IntVT, 3);
130   auto IdxVT = EVT::getIntegerVT(Context, 64);
131   auto Vec = DAG->getConstant(1, Loc, VecVT);
132   auto ZeroIdx = DAG->getConstant(0, Loc, IdxVT);
133   auto Op = DAG->getNode(ISD::EXTRACT_SUBVECTOR, Loc, VecVT, Vec, ZeroIdx);
134   auto DemandedElts = APInt(3, 7);
135   EXPECT_EQ(DAG->ComputeNumSignBits(Op, DemandedElts), 7u);
136 }
137 
138 TEST_F(AArch64SelectionDAGTest, SimplifyDemandedVectorElts_EXTRACT_SUBVECTOR) {
139   if (!TM)
140     return;
141 
142   TargetLowering TL(*TM);
143 
144   SDLoc Loc;
145   auto IntVT = EVT::getIntegerVT(Context, 8);
146   auto VecVT = EVT::getVectorVT(Context, IntVT, 3);
147   auto IdxVT = EVT::getIntegerVT(Context, 64);
148   auto Vec = DAG->getConstant(1, Loc, VecVT);
149   auto ZeroIdx = DAG->getConstant(0, Loc, IdxVT);
150   auto Op = DAG->getNode(ISD::EXTRACT_SUBVECTOR, Loc, VecVT, Vec, ZeroIdx);
151   auto DemandedElts = APInt(3, 7);
152   auto KnownUndef = APInt(3, 0);
153   auto KnownZero = APInt(3, 0);
154   TargetLowering::TargetLoweringOpt TLO(*DAG, false, false);
155   EXPECT_EQ(TL.SimplifyDemandedVectorElts(Op, DemandedElts, KnownUndef,
156                                           KnownZero, TLO),
157             false);
158 }
159 
160 // Piggy-backing on the AArch64 tests to verify SelectionDAG::computeKnownBits.
161 TEST_F(AArch64SelectionDAGTest, ComputeKnownBits_ADD) {
162   if (!TM)
163     return;
164   SDLoc Loc;
165   auto IntVT = EVT::getIntegerVT(Context, 8);
166   auto UnknownOp = DAG->getRegister(0, IntVT);
167   auto Mask = DAG->getConstant(0x8A, Loc, IntVT);
168   auto N0 = DAG->getNode(ISD::AND, Loc, IntVT, Mask, UnknownOp);
169   auto N1 = DAG->getConstant(0x55, Loc, IntVT);
170   auto Op = DAG->getNode(ISD::ADD, Loc, IntVT, N0, N1);
171   // N0 = ?000?0?0
172   // N1 = 01010101
173   //  =>
174   // Known.One  = 01010101 (0x55)
175   // Known.Zero = 00100000 (0x20)
176   KnownBits Known = DAG->computeKnownBits(Op);
177   EXPECT_EQ(Known.Zero, APInt(8, 0x20));
178   EXPECT_EQ(Known.One, APInt(8, 0x55));
179 }
180 
181 // Piggy-backing on the AArch64 tests to verify SelectionDAG::computeKnownBits.
182 TEST_F(AArch64SelectionDAGTest, ComputeKnownBits_SUB) {
183   if (!TM)
184     return;
185   SDLoc Loc;
186   auto IntVT = EVT::getIntegerVT(Context, 8);
187   auto N0 = DAG->getConstant(0x55, Loc, IntVT);
188   auto UnknownOp = DAG->getRegister(0, IntVT);
189   auto Mask = DAG->getConstant(0x2e, Loc, IntVT);
190   auto N1 = DAG->getNode(ISD::AND, Loc, IntVT, Mask, UnknownOp);
191   auto Op = DAG->getNode(ISD::SUB, Loc, IntVT, N0, N1);
192   // N0 = 01010101
193   // N1 = 00?0???0
194   //  =>
195   // Known.One  = 00000001 (0x1)
196   // Known.Zero = 10000000 (0x80)
197   KnownBits Known = DAG->computeKnownBits(Op);
198   EXPECT_EQ(Known.Zero, APInt(8, 0x80));
199   EXPECT_EQ(Known.One, APInt(8, 0x1));
200 }
201 
202 } // end anonymous namespace
203