R600/SI: Add getInstrInfo helper

[arsenm]

Summary

Having static_cast<const SIInstrInfo *>(getTargetMachine().getSubtargetImpl()->getInstrInfo()) littered everywhere is horrible, so add a wrapper for it.

[echristo]

This could also be written as
getTargetMachine().getSubtarget<R600Subtarget>().getInstrInfo() and
then it's shorter but still leaves the full line. It's going to keep
changing for a bit so a helper function might be a bit premature.

-eric

lib/Target/R600/SIISelLowering.h

   static SDValue performUCharToFloatCombine(SDNode *N,
                                             DAGCombinerInfo &DCI);
 
+  const SIInstrInfo *getInstrInfo() const;
 public:
   SITargetLowering(TargetMachine &tm);
   bool allowsMisalignedMemoryAccesses(EVT VT, unsigned AS,

lib/Target/R600/SIISelLowering.cpp

   setSchedulingPreference(Sched::RegPressure);
 }
 
+const SIInstrInfo *SITargetLowering::getInstrInfo() const {
+  auto STM = getTargetMachine().getSubtargetImpl();
+  return static_cast<const SIInstrInfo *>(STM->getInstrInfo());
+}
+
 //===----------------------------------------------------------------------===//
 // TargetLowering queries
 //===----------------------------------------------------------------------===//

 
 bool SITargetLowering::shouldConvertConstantLoadToIntImm(const APInt &Imm,
                                                          Type *Ty) const {
-  const SIInstrInfo *TII = static_cast<const SIInstrInfo *>(
-      getTargetMachine().getSubtargetImpl()->getInstrInfo());
+  const SIInstrInfo *TII = getInstrInfo();
   return TII->isInlineConstant(Imm);
 }
 

     MachineInstr * MI, MachineBasicBlock * BB) const {
 
   MachineBasicBlock::iterator I = *MI;
-  const SIInstrInfo *TII = static_cast<const SIInstrInfo *>(
-      getTargetMachine().getSubtargetImpl()->getInstrInfo());
+  const SIInstrInfo *TII = getInstrInfo();
   MachineRegisterInfo &MRI = BB->getParent()->getRegInfo();
 
   switch (MI->getOpcode()) {

   }
   case AMDGPU::FABS_SI: {
     MachineRegisterInfo &MRI = BB->getParent()->getRegInfo();
-    const SIInstrInfo *TII = static_cast<const SIInstrInfo *>(
-        getTargetMachine().getSubtargetImpl()->getInstrInfo());
+    const SIInstrInfo *TII = getInstrInfo();
     DebugLoc DL = MI->getDebugLoc();
     unsigned DestReg = MI->getOperand(0).getReg();
     unsigned Reg = MRI.createVirtualRegister(&AMDGPU::VReg_32RegClass);

   }
   case AMDGPU::FABS64_SI: {
     MachineRegisterInfo &MRI = BB->getParent()->getRegInfo();
-    const SIInstrInfo *TII = static_cast<const SIInstrInfo *>(
-      getTargetMachine().getSubtargetImpl()->getInstrInfo());
+    const SIInstrInfo *TII = getInstrInfo();
 
     DebugLoc DL = MI->getDebugLoc();
     unsigned SuperReg = MI->getOperand(0).getReg();

   }
   case AMDGPU::FNEG_SI: {
     MachineRegisterInfo &MRI = BB->getParent()->getRegInfo();
-    const SIInstrInfo *TII = static_cast<const SIInstrInfo *>(
-        getTargetMachine().getSubtargetImpl()->getInstrInfo());
+    const SIInstrInfo *TII = getInstrInfo();
     DebugLoc DL = MI->getDebugLoc();
     unsigned DestReg = MI->getOperand(0).getReg();
     unsigned Reg = MRI.createVirtualRegister(&AMDGPU::VReg_32RegClass);

   }
   case AMDGPU::FNEG64_SI: {
     MachineRegisterInfo &MRI = BB->getParent()->getRegInfo();
-    const SIInstrInfo *TII = static_cast<const SIInstrInfo *>(
-        getTargetMachine().getSubtargetImpl()->getInstrInfo());
+    const SIInstrInfo *TII = getInstrInfo();
 
     DebugLoc DL = MI->getDebugLoc();
     unsigned SrcReg = MI->getOperand(1).getReg();

     break;
   }
   case AMDGPU::FCLAMP_SI: {
-    const SIInstrInfo *TII = static_cast<const SIInstrInfo *>(
-        getTargetMachine().getSubtargetImpl()->getInstrInfo());
+    const SIInstrInfo *TII = getInstrInfo();
     DebugLoc DL = MI->getDebugLoc();
     unsigned DestReg = MI->getOperand(0).getReg();
     BuildMI(*BB, I, DL, TII->get(AMDGPU::V_ADD_F32_e64), DestReg)

 SDValue SITargetLowering::LowerFrameIndex(SDValue Op, SelectionDAG &DAG) const {
 
   MachineFunction &MF = DAG.getMachineFunction();
-  const SIInstrInfo *TII = static_cast<const SIInstrInfo *>(
-      getTargetMachine().getSubtargetImpl()->getInstrInfo());
+  const SIInstrInfo *TII = getInstrInfo();
   const SIRegisterInfo &TRI = TII->getRegisterInfo();
   FrameIndexSDNode *FINode = cast<FrameIndexSDNode>(Op);
   unsigned FrameIndex = FINode->getIndex();

                                bool &ScalarSlotUsed) const {
 
   MachineSDNode *Mov = dyn_cast<MachineSDNode>(Operand);
-  const SIInstrInfo *TII = static_cast<const SIInstrInfo *>(
-      getTargetMachine().getSubtargetImpl()->getInstrInfo());
+  const SIInstrInfo *TII = getInstrInfo();
   if (!Mov || !TII->isMov(Mov->getMachineOpcode()))
     return false;
 

 
 const TargetRegisterClass *SITargetLowering::getRegClassForNode(
                                    SelectionDAG &DAG, const SDValue &Op) const {
-  const SIInstrInfo *TII = static_cast<const SIInstrInfo *>(
-      getTargetMachine().getSubtargetImpl()->getInstrInfo());
+  const SIInstrInfo *TII = getInstrInfo();
   const SIRegisterInfo &TRI = TII->getRegisterInfo();
 
   if (!Op->isMachineOpcode()) {

 
   // Original encoding (either e32 or e64)
   int Opcode = Node->getMachineOpcode();
-  const SIInstrInfo *TII = static_cast<const SIInstrInfo *>(
-      getTargetMachine().getSubtargetImpl()->getInstrInfo());
+  const SIInstrInfo *TII = getInstrInfo();
   const MCInstrDesc *Desc = &TII->get(Opcode);
 
   unsigned NumDefs = Desc->getNumDefs();

 /// \brief Fold the instructions after selecting them.
 SDNode *SITargetLowering::PostISelFolding(MachineSDNode *Node,
                                           SelectionDAG &DAG) const {
-  const SIInstrInfo *TII = static_cast<const SIInstrInfo *>(
-      getTargetMachine().getSubtargetImpl()->getInstrInfo());
+  const SIInstrInfo *TII = getInstrInfo();
   Node = AdjustRegClass(Node, DAG);
 
   if (TII->isMIMG(Node->getMachineOpcode()))

 /// bits set in the writemask
 void SITargetLowering::AdjustInstrPostInstrSelection(MachineInstr *MI,
                                                      SDNode *Node) const {
-  const SIInstrInfo *TII = static_cast<const SIInstrInfo *>(
-      getTargetMachine().getSubtargetImpl()->getInstrInfo());
+  const SIInstrInfo *TII = getInstrInfo();
   if (!TII->isMIMG(MI->getOpcode()))
     return;