AArch64: Clean up some casts to target subclasses (#165189)

Prefer getSubtarget<AArch64>(). Also avoids one unnecessary
null check.

Author: arsenm

llvm/lib/Target/AArch64/AArch64BranchTargets.cpp

@@ -47,6 +47,8 @@ class AArch64BranchTargets : public MachineFunctionPass {
   StringRef getPassName() const override { return AARCH64_BRANCH_TARGETS_NAME; }
 
 private:
+  const AArch64Subtarget *Subtarget;
+
   void addBTI(MachineBasicBlock &MBB, bool CouldCall, bool CouldJump,
               bool NeedsWinCFI);
 };
@@ -75,6 +77,8 @@ bool AArch64BranchTargets::runOnMachineFunction(MachineFunction &MF) {
                     << "********** Function: " << MF.getName() << '\n');
   const Function &F = MF.getFunction();
 
+  Subtarget = &MF.getSubtarget<AArch64Subtarget>();
+
   // LLVM does not consider basic blocks which are the targets of jump tables
   // to be address-taken (the address can't escape anywhere else), but they are
   // used for indirect branches, so need BTI instructions.
@@ -100,9 +104,8 @@ bool AArch64BranchTargets::runOnMachineFunction(MachineFunction &MF) {
     // a BTI, and pointing the indirect branch at that. For non-ELF targets we
     // can't rely on that, so we assume that `CouldCall` is _always_ true due
     // to the risk of long-branch thunks at link time.
-    if (&MBB == &*MF.begin() &&
-        (!MF.getSubtarget<AArch64Subtarget>().isTargetELF() ||
-         (F.hasAddressTaken() || !F.hasLocalLinkage())))
+    if (&MBB == &*MF.begin() && (!Subtarget->isTargetELF() ||
+                                 (F.hasAddressTaken() || !F.hasLocalLinkage())))
       CouldCall = true;
 
     // If the block itself is address-taken, it could be indirectly branched
@@ -132,9 +135,6 @@ void AArch64BranchTargets::addBTI(MachineBasicBlock &MBB, bool CouldCall,
                     << (CouldCall ? "c" : "") << " to " << MBB.getName()
                     << "\n");
 
-  const AArch64InstrInfo *TII = static_cast<const AArch64InstrInfo *>(
-      MBB.getParent()->getSubtarget().getInstrInfo());
-
   unsigned HintNum = 32;
   if (CouldCall)
     HintNum |= 2;
@@ -162,6 +162,8 @@ void AArch64BranchTargets::addBTI(MachineBasicBlock &MBB, bool CouldCall,
        MBBI->getOpcode() == AArch64::PACIBSP))
     return;
 
+  const AArch64InstrInfo *TII = Subtarget->getInstrInfo();
+
   // Insert BTI exactly at the first executable instruction.
   const DebugLoc DL = MBB.findDebugLoc(MBBI);
   MachineInstr *BTI = BuildMI(MBB, MBBI, DL, TII->get(AArch64::HINT))

llvm/lib/Target/AArch64/AArch64ExpandPseudoInsts.cpp

@@ -1871,7 +1871,7 @@ bool AArch64ExpandPseudo::expandMBB(MachineBasicBlock &MBB) {
 }
 
 bool AArch64ExpandPseudo::runOnMachineFunction(MachineFunction &MF) {
-  TII = static_cast<const AArch64InstrInfo *>(MF.getSubtarget().getInstrInfo());
+  TII = MF.getSubtarget<AArch64Subtarget>().getInstrInfo();
 
   bool Modified = false;
   for (auto &MBB : MF)

llvm/lib/Target/AArch64/AArch64FrameLowering.cpp

@@ -644,10 +644,10 @@ bool AArch64FrameLowering::hasReservedCallFrame(
 MachineBasicBlock::iterator AArch64FrameLowering::eliminateCallFramePseudoInstr(
     MachineFunction &MF, MachineBasicBlock &MBB,
     MachineBasicBlock::iterator I) const {
-  const AArch64InstrInfo *TII =
-      static_cast<const AArch64InstrInfo *>(MF.getSubtarget().getInstrInfo());
-  const AArch64TargetLowering *TLI =
-      MF.getSubtarget<AArch64Subtarget>().getTargetLowering();
+
+  const AArch64Subtarget &Subtarget = MF.getSubtarget<AArch64Subtarget>();
+  const AArch64InstrInfo *TII = Subtarget.getInstrInfo();
+  const AArch64TargetLowering *TLI = Subtarget.getTargetLowering();
   [[maybe_unused]] MachineFrameInfo &MFI = MF.getFrameInfo();
   DebugLoc DL = I->getDebugLoc();
   unsigned Opc = I->getOpcode();
@@ -1319,8 +1319,8 @@ StackOffset AArch64FrameLowering::getStackOffset(const MachineFunction &MF,
 // TODO: This function currently does not work for scalable vectors.
 int AArch64FrameLowering::getSEHFrameIndexOffset(const MachineFunction &MF,
                                                  int FI) const {
-  const auto *RegInfo = static_cast<const AArch64RegisterInfo *>(
-      MF.getSubtarget().getRegisterInfo());
+  const AArch64RegisterInfo *RegInfo =
+      MF.getSubtarget<AArch64Subtarget>().getRegisterInfo();
   int ObjectOffset = MF.getFrameInfo().getObjectOffset(FI);
   return RegInfo->getLocalAddressRegister(MF) == AArch64::FP
              ? getFPOffset(MF, ObjectOffset).getFixed()
@@ -1343,10 +1343,9 @@ StackOffset AArch64FrameLowering::resolveFrameOffsetReference(
     TargetStackID::Value StackID, Register &FrameReg, bool PreferFP,
     bool ForSimm) const {
   const auto &MFI = MF.getFrameInfo();
-  const auto *RegInfo = static_cast<const AArch64RegisterInfo *>(
-      MF.getSubtarget().getRegisterInfo());
-  const auto *AFI = MF.getInfo<AArch64FunctionInfo>();
   const auto &Subtarget = MF.getSubtarget<AArch64Subtarget>();
+  const AArch64RegisterInfo *RegInfo = Subtarget.getRegisterInfo();
+  const auto *AFI = MF.getInfo<AArch64FunctionInfo>();
 
   int64_t FPOffset = getFPOffset(MF, ObjectOffset).getFixed();
   int64_t Offset = getStackOffset(MF, ObjectOffset).getFixed();
@@ -2443,8 +2442,7 @@ void AArch64FrameLowering::determineCalleeSaves(MachineFunction &MF,
   const AArch64Subtarget &Subtarget = MF.getSubtarget<AArch64Subtarget>();
 
   TargetFrameLowering::determineCalleeSaves(MF, SavedRegs, RS);
-  const AArch64RegisterInfo *RegInfo = static_cast<const AArch64RegisterInfo *>(
-      MF.getSubtarget().getRegisterInfo());
+  const AArch64RegisterInfo *RegInfo = Subtarget.getRegisterInfo();
   AArch64FunctionInfo *AFI = MF.getInfo<AArch64FunctionInfo>();
   unsigned UnspilledCSGPR = AArch64::NoRegister;
   unsigned UnspilledCSGPRPaired = AArch64::NoRegister;

llvm/lib/Target/AArch64/AArch64LowerHomogeneousPrologEpilog.cpp

@@ -649,7 +649,7 @@ bool AArch64LowerHomogeneousPE::runOnMBB(MachineBasicBlock &MBB) {
 }
 
 bool AArch64LowerHomogeneousPE::runOnMachineFunction(MachineFunction &MF) {
-  TII = static_cast<const AArch64InstrInfo *>(MF.getSubtarget().getInstrInfo());
+  TII = MF.getSubtarget<AArch64Subtarget>().getInstrInfo();
 
   bool Modified = false;
   for (auto &MBB : MF)

llvm/lib/Target/AArch64/AArch64SIMDInstrOpt.cpp

@@ -33,6 +33,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "AArch64InstrInfo.h"
+#include "AArch64Subtarget.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/StringRef.h"
@@ -49,8 +50,8 @@
 #include "llvm/MC/MCInstrDesc.h"
 #include "llvm/MC/MCSchedule.h"
 #include "llvm/Pass.h"
-#include <unordered_map>
 #include <map>
+#include <unordered_map>
 
 using namespace llvm;
 
@@ -67,7 +68,7 @@ namespace {
 struct AArch64SIMDInstrOpt : public MachineFunctionPass {
   static char ID;
 
-  const TargetInstrInfo *TII;
+  const AArch64InstrInfo *TII;
   MachineRegisterInfo *MRI;
   TargetSchedModel SchedModel;
 
@@ -694,13 +695,9 @@ bool AArch64SIMDInstrOpt::runOnMachineFunction(MachineFunction &MF) {
   if (skipFunction(MF.getFunction()))
     return false;
 
-  TII = MF.getSubtarget().getInstrInfo();
   MRI = &MF.getRegInfo();
-  const TargetSubtargetInfo &ST = MF.getSubtarget();
-  const AArch64InstrInfo *AAII =
-      static_cast<const AArch64InstrInfo *>(ST.getInstrInfo());
-  if (!AAII)
-    return false;
+  const AArch64Subtarget &ST = MF.getSubtarget<AArch64Subtarget>();
+  TII = ST.getInstrInfo();
   SchedModel.init(&ST);
   if (!SchedModel.hasInstrSchedModel())
     return false;