xref: /freebsd/contrib/llvm-project/llvm/lib/Target/AMDGPU/AMDGPUMacroFusion.cpp (revision 0b57cec536236d46e3dba9bd041533462f33dbb7)
1*0b57cec5SDimitry Andric //===--- AMDGPUMacroFusion.cpp - AMDGPU Macro Fusion ----------------------===//
2*0b57cec5SDimitry Andric //
3*0b57cec5SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4*0b57cec5SDimitry Andric // See https://llvm.org/LICENSE.txt for license information.
5*0b57cec5SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6*0b57cec5SDimitry Andric //
7*0b57cec5SDimitry Andric //===----------------------------------------------------------------------===//
8*0b57cec5SDimitry Andric //
9*0b57cec5SDimitry Andric /// \file This file contains the AMDGPU implementation of the DAG scheduling
10*0b57cec5SDimitry Andric ///  mutation to pair instructions back to back.
11*0b57cec5SDimitry Andric //
12*0b57cec5SDimitry Andric //===----------------------------------------------------------------------===//
13*0b57cec5SDimitry Andric 
14*0b57cec5SDimitry Andric #include "AMDGPUMacroFusion.h"
15*0b57cec5SDimitry Andric #include "AMDGPUSubtarget.h"
16*0b57cec5SDimitry Andric #include "SIInstrInfo.h"
17*0b57cec5SDimitry Andric #include "MCTargetDesc/AMDGPUMCTargetDesc.h"
18*0b57cec5SDimitry Andric 
19*0b57cec5SDimitry Andric #include "llvm/CodeGen/MacroFusion.h"
20*0b57cec5SDimitry Andric 
21*0b57cec5SDimitry Andric using namespace llvm;
22*0b57cec5SDimitry Andric 
23*0b57cec5SDimitry Andric namespace {
24*0b57cec5SDimitry Andric 
25*0b57cec5SDimitry Andric /// Check if the instr pair, FirstMI and SecondMI, should be fused
26*0b57cec5SDimitry Andric /// together. Given SecondMI, when FirstMI is unspecified, then check if
27*0b57cec5SDimitry Andric /// SecondMI may be part of a fused pair at all.
28*0b57cec5SDimitry Andric static bool shouldScheduleAdjacent(const TargetInstrInfo &TII_,
29*0b57cec5SDimitry Andric                                    const TargetSubtargetInfo &TSI,
30*0b57cec5SDimitry Andric                                    const MachineInstr *FirstMI,
31*0b57cec5SDimitry Andric                                    const MachineInstr &SecondMI) {
32*0b57cec5SDimitry Andric   const SIInstrInfo &TII = static_cast<const SIInstrInfo&>(TII_);
33*0b57cec5SDimitry Andric 
34*0b57cec5SDimitry Andric   switch (SecondMI.getOpcode()) {
35*0b57cec5SDimitry Andric   case AMDGPU::V_ADDC_U32_e64:
36*0b57cec5SDimitry Andric   case AMDGPU::V_SUBB_U32_e64:
37*0b57cec5SDimitry Andric   case AMDGPU::V_CNDMASK_B32_e64: {
38*0b57cec5SDimitry Andric     // Try to cluster defs of condition registers to their uses. This improves
39*0b57cec5SDimitry Andric     // the chance VCC will be available which will allow shrinking to VOP2
40*0b57cec5SDimitry Andric     // encodings.
41*0b57cec5SDimitry Andric     if (!FirstMI)
42*0b57cec5SDimitry Andric       return true;
43*0b57cec5SDimitry Andric 
44*0b57cec5SDimitry Andric     const MachineBasicBlock &MBB = *FirstMI->getParent();
45*0b57cec5SDimitry Andric     const MachineRegisterInfo &MRI = MBB.getParent()->getRegInfo();
46*0b57cec5SDimitry Andric     const TargetRegisterInfo *TRI = MRI.getTargetRegisterInfo();
47*0b57cec5SDimitry Andric     const MachineOperand *Src2 = TII.getNamedOperand(SecondMI,
48*0b57cec5SDimitry Andric                                                      AMDGPU::OpName::src2);
49*0b57cec5SDimitry Andric     return FirstMI->definesRegister(Src2->getReg(), TRI);
50*0b57cec5SDimitry Andric   }
51*0b57cec5SDimitry Andric   default:
52*0b57cec5SDimitry Andric     return false;
53*0b57cec5SDimitry Andric   }
54*0b57cec5SDimitry Andric 
55*0b57cec5SDimitry Andric   return false;
56*0b57cec5SDimitry Andric }
57*0b57cec5SDimitry Andric 
58*0b57cec5SDimitry Andric } // end namespace
59*0b57cec5SDimitry Andric 
60*0b57cec5SDimitry Andric 
61*0b57cec5SDimitry Andric namespace llvm {
62*0b57cec5SDimitry Andric 
63*0b57cec5SDimitry Andric std::unique_ptr<ScheduleDAGMutation> createAMDGPUMacroFusionDAGMutation () {
64*0b57cec5SDimitry Andric   return createMacroFusionDAGMutation(shouldScheduleAdjacent);
65*0b57cec5SDimitry Andric }
66*0b57cec5SDimitry Andric 
67*0b57cec5SDimitry Andric } // end namespace llvm
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