1 //===- llvm/unittests/Target/AMDGPU/ExecMayBeModifiedBeforeAnyUse.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 "AMDGPUTargetMachine.h"
10 #include "GCNSubtarget.h"
11 #include "MCTargetDesc/AMDGPUMCTargetDesc.h"
12 #include "llvm/CodeGen/MachineModuleInfo.h"
13 #include "llvm/CodeGen/TargetSubtargetInfo.h"
14 #include "llvm/MC/MCTargetOptions.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 #include <thread>
20 
21 using namespace llvm;
22 
23 // implementation is in the llvm/unittests/Target/AMDGPU/DwarfRegMappings.cpp
24 std::unique_ptr<const GCNTargetMachine>
25 createTargetMachine(std::string TStr, StringRef CPU, StringRef FS);
26 
27 TEST(AMDGPUExecMayBeModifiedBeforeAnyUse, TheTest) {
28   auto TM = createTargetMachine("amdgcn-amd-", "gfx906", "");
29   if (!TM)
30     return;
31 
32   GCNSubtarget ST(TM->getTargetTriple(), std::string(TM->getTargetCPU()),
33                   std::string(TM->getTargetFeatureString()), *TM);
34 
35   LLVMContext Ctx;
36   Module Mod("Module", Ctx);
37   Mod.setDataLayout(TM->createDataLayout());
38 
39   auto *Type = FunctionType::get(Type::getVoidTy(Ctx), false);
40   auto *F = Function::Create(Type, GlobalValue::ExternalLinkage, "Test", &Mod);
41 
42   MachineModuleInfo MMI(TM.get());
43   auto MF = std::make_unique<MachineFunction>(*F, *TM, ST, 42, MMI);
44   auto *BB = MF->CreateMachineBasicBlock();
45   MF->push_back(BB);
46 
47   auto E = BB->end();
48   DebugLoc DL;
49   const auto &TII = *ST.getInstrInfo();
50   auto &MRI = MF->getRegInfo();
51 
52   // create machine IR
53   Register R = MRI.createVirtualRegister(&AMDGPU::SReg_32RegClass);
54 
55   MachineInstr *DefMI =
56       BuildMI(*BB, E, DL, TII.get(AMDGPU::S_MOV_B32), R).addImm(42).getInstr();
57 
58   auto First =
59       BuildMI(*BB, E, DL, TII.get(AMDGPU::S_NOP)).addReg(R, RegState::Implicit);
60 
61   BuildMI(*BB, E, DL, TII.get(AMDGPU::S_NOP)).addReg(R, RegState::Implicit);
62 
63   // this violates the continuous sequence of R's uses for the first S_NOP
64   First.addReg(R, RegState::Implicit);
65 
66 #ifdef DEBUG_THIS_TEST
67   MF->dump();
68   MRI.dumpUses(R);
69 #endif
70 
71   // make sure execMayBeModifiedBeforeAnyUse doesn't crash
72   ASSERT_FALSE(execMayBeModifiedBeforeAnyUse(MRI, R, *DefMI));
73 }
74