1 //===-- SIFixVGPRCopies.cpp - Fix VGPR Copies after regalloc --------------===//
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 /// \file
10 /// Add implicit use of exec to vector register copies.
11 ///
12 //===----------------------------------------------------------------------===//
13 
14 #include "AMDGPU.h"
15 #include "GCNSubtarget.h"
16 #include "MCTargetDesc/AMDGPUMCTargetDesc.h"
17 #include "llvm/CodeGen/MachineFunctionPass.h"
18 
19 using namespace llvm;
20 
21 #define DEBUG_TYPE "si-fix-vgpr-copies"
22 
23 namespace {
24 
25 class SIFixVGPRCopies : public MachineFunctionPass {
26 public:
27   static char ID;
28 
29 public:
30   SIFixVGPRCopies() : MachineFunctionPass(ID) {
31     initializeSIFixVGPRCopiesPass(*PassRegistry::getPassRegistry());
32   }
33 
34   bool runOnMachineFunction(MachineFunction &MF) override;
35 
36   StringRef getPassName() const override { return "SI Fix VGPR copies"; }
37 };
38 
39 } // End anonymous namespace.
40 
41 INITIALIZE_PASS(SIFixVGPRCopies, DEBUG_TYPE, "SI Fix VGPR copies", false, false)
42 
43 char SIFixVGPRCopies::ID = 0;
44 
45 char &llvm::SIFixVGPRCopiesID = SIFixVGPRCopies::ID;
46 
47 bool SIFixVGPRCopies::runOnMachineFunction(MachineFunction &MF) {
48   const GCNSubtarget &ST = MF.getSubtarget<GCNSubtarget>();
49   const SIRegisterInfo *TRI = ST.getRegisterInfo();
50   const SIInstrInfo *TII = ST.getInstrInfo();
51   bool Changed = false;
52 
53   for (MachineBasicBlock &MBB : MF) {
54     for (MachineInstr &MI : MBB) {
55       switch (MI.getOpcode()) {
56       case AMDGPU::COPY:
57         if (TII->isVGPRCopy(MI) && !MI.readsRegister(AMDGPU::EXEC, TRI)) {
58           MI.addOperand(MF,
59                         MachineOperand::CreateReg(AMDGPU::EXEC, false, true));
60           LLVM_DEBUG(dbgs() << "Add exec use to " << MI);
61           Changed = true;
62         }
63         break;
64       default:
65         break;
66       }
67     }
68   }
69 
70   return Changed;
71 }
72