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 "AMDGPUSubtarget.h"
10 #include "AMDGPUTargetMachine.h"
11 #include "llvm/CodeGen/MachineModuleInfo.h"
12 #include "llvm/CodeGen/TargetSubtargetInfo.h"
13 #include "llvm/MC/MCTargetOptions.h"
14 #include "llvm/Support/TargetRegistry.h"
15 #include "llvm/Support/TargetSelect.h"
16 #include "llvm/Target/TargetMachine.h"
17 #include "gtest/gtest.h"
18 #include <thread>
19 
20 using namespace llvm;
21 
22 // implementation is in the llvm/unittests/Target/AMDGPU/DwarfRegMappings.cpp
23 std::unique_ptr<const GCNTargetMachine>
24 createTargetMachine(std::string TStr, StringRef CPU, StringRef FS);
25 
26 TEST(AMDGPUExecMayBeModifiedBeforeAnyUse, TheTest) {
27   auto TM = createTargetMachine("amdgcn-amd-", "gfx906", "");
28   if (!TM)
29     return;
30 
31   GCNSubtarget ST(TM->getTargetTriple(), std::string(TM->getTargetCPU()),
32                   std::string(TM->getTargetFeatureString()), *TM);
33 
34   LLVMContext Ctx;
35   Module Mod("Module", Ctx);
36   Mod.setDataLayout(TM->createDataLayout());
37 
38   auto *Type = FunctionType::get(Type::getVoidTy(Ctx), false);
39   auto *F = Function::Create(Type, GlobalValue::ExternalLinkage, "Test", &Mod);
40 
41   MachineModuleInfo MMI(TM.get());
42   auto MF = std::make_unique<MachineFunction>(*F, *TM, ST, 42, MMI);
43   auto *BB = MF->CreateMachineBasicBlock();
44   MF->push_back(BB);
45 
46   auto E = BB->end();
47   DebugLoc DL;
48   const auto &TII = *ST.getInstrInfo();
49   auto &MRI = MF->getRegInfo();
50 
51   // create machine IR
52   Register R = MRI.createVirtualRegister(&AMDGPU::SReg_32RegClass);
53 
54   MachineInstr *DefMI =
55       BuildMI(*BB, E, DL, TII.get(AMDGPU::S_MOV_B32), R).addImm(42).getInstr();
56 
57   auto First =
58       BuildMI(*BB, E, DL, TII.get(AMDGPU::S_NOP)).addReg(R, RegState::Implicit);
59 
60   BuildMI(*BB, E, DL, TII.get(AMDGPU::S_NOP)).addReg(R, RegState::Implicit);
61 
62   // this violates the continuous sequence of R's uses for the first S_NOP
63   First.addReg(R, RegState::Implicit);
64 
65 #ifdef DEBUG_THIS_TEST
66   MF->dump();
67   MRI.dumpUses(R);
68 #endif
69 
70   // make sure execMayBeModifiedBeforeAnyUse doesn't crash
71   ASSERT_FALSE(execMayBeModifiedBeforeAnyUse(MRI, R, *DefMI));
72 }
73