AMDGPU/GlobalISel: Select G_FRAME_INDEX

[tstellar]

LGTM.

[arsenm]

r364789

lib/Target/AMDGPU/AMDGPUInstructionSelector.h

private:
   bool hasVgprParts(ArrayRef<GEPInfo> AddrInfo) const;
   void getAddrModeInfo(const MachineInstr &Load, const MachineRegisterInfo &MRI,
                        SmallVectorImpl<GEPInfo> &AddrInfo) const;
   bool selectSMRD(MachineInstr &I, ArrayRef<GEPInfo> AddrInfo) const;
   bool selectG_LOAD(MachineInstr &I) const;
   bool selectG_SELECT(MachineInstr &I) const;
   bool selectG_STORE(MachineInstr &I) const;
   bool selectG_BRCOND(MachineInstr &I) const;
+  bool selectG_FRAME_INDEX(MachineInstr &I) const;
 
   std::pair<Register, unsigned>
   selectVOP3ModsImpl(Register Src, const MachineRegisterInfo &MRI) const;
 
   InstructionSelector::ComplexRendererFns
   selectVCSRC(MachineOperand &Root) const;
 
   InstructionSelector::ComplexRendererFns

lib/Target/AMDGPU/AMDGPUInstructionSelector.cpp

BuildMI(*BB, &I, DL, TII.get(AMDGPU::COPY), CondPhysReg)
     .addReg(CondReg);
   BuildMI(*BB, &I, DL, TII.get(BrOpcode))
     .addMBB(I.getOperand(1).getMBB());
 
   I.eraseFromParent();
   return true;
 }
 
+bool AMDGPUInstructionSelector::selectG_FRAME_INDEX(MachineInstr &I) const {
+  MachineBasicBlock *BB = I.getParent();
+  MachineFunction *MF = BB->getParent();
+  MachineRegisterInfo &MRI = MF->getRegInfo();
+
+  Register DstReg = I.getOperand(0).getReg();
+  const RegisterBank *DstRB = RBI.getRegBank(DstReg, MRI, TRI);
+  const bool IsVGPR = DstRB->getID() == AMDGPU::VGPRRegBankID;
+  I.setDesc(TII.get(IsVGPR ? AMDGPU::V_MOV_B32_e32 : AMDGPU::S_MOV_B32));
+  if (IsVGPR)
+    I.addOperand(*MF, MachineOperand::CreateReg(AMDGPU::EXEC, false, true));
+
+  return RBI.constrainGenericRegister(
+    DstReg, IsVGPR ? AMDGPU::VGPR_32RegClass : AMDGPU::SReg_32RegClass, MRI);
+}
+
 bool AMDGPUInstructionSelector::select(MachineInstr &I,
                                        CodeGenCoverage &CoverageInfo) const {
 
   if (!isPreISelGenericOpcode(I.getOpcode())) {
     if (I.isCopy())
       return selectCOPY(I);
     return true;
   }
case TargetOpcode::G_ANYEXT:
     if (selectG_SZA_EXT(I)) {
       I.eraseFromParent();
       return true;
     }
 
     return false;
   case TargetOpcode::G_BRCOND:
     return selectG_BRCOND(I);
+  case TargetOpcode::G_FRAME_INDEX:
+    return selectG_FRAME_INDEX(I);
   }
   return false;
 }
 
 InstructionSelector::ComplexRendererFns
 AMDGPUInstructionSelector::selectVCSRC(MachineOperand &Root) const {
   return {{
       [=](MachineInstrBuilder &MIB) { MIB.add(Root); }

test/CodeGen/AMDGPU/GlobalISel/inst-select-frame-index.mir

+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -march=amdgcn -run-pass=instruction-select -verify-machineinstrs %s -o - | FileCheck %s -check-prefix=GCN
+
+---
+
+name: frame_index_s
+legalized:       true
+regBankSelected: true
+stack:
+  - { id: 0, size: 4, alignment: 4 }
+
+body: |
+  bb.0:
+    ; GCN-LABEL: name: frame_index_s
+    ; GCN: [[S_MOV_B32_:%[0-9]+]]:sreg_32_xm0 = S_MOV_B32 %stack.0
+    ; GCN: $sgpr0 = COPY [[S_MOV_B32_]]
+    %0:sgpr(p5) = G_FRAME_INDEX %stack.0
+    $sgpr0 = COPY %0
+
+...
+
+---
+
+name: frame_index_v
+legalized:       true
+regBankSelected: true
+stack:
+  - { id: 0, size: 4, alignment: 4 }
+
+body: |
+  bb.0:
+    ; GCN-LABEL: name: frame_index_v
+    ; GCN: [[V_MOV_B32_e32_:%[0-9]+]]:vgpr_32 = V_MOV_B32_e32 %stack.0, implicit $exec
+    ; GCN: $vgpr0 = COPY [[V_MOV_B32_e32_]]
+    %0:vgpr(p5) = G_FRAME_INDEX %stack.0
+    $vgpr0 = COPY %0
+
+...