MachineBasicBlock: Factor out common code into isReturnBlock()

llvm-svn: 248617

llvm/include/llvm/CodeGen/MachineBasicBlock.h

@@ -496,6 +496,12 @@ public:
     return const_cast<MachineBasicBlock *>(this)->getLastNonDebugInstr();
   }
 
+  /// Convenience function that returns true if the block has no successors and
+  /// contains a return instruction.
+  bool isReturnBlock() const {
+    return !empty() && back().isReturn();
+  }
+
   /// Split the critical edge from this block to the given successor block, and
   /// return the newly created block, or null if splitting is not possible.
   ///

llvm/lib/CodeGen/AggressiveAntiDepBreaker.cpp

@@ -142,7 +142,7 @@ void AggressiveAntiDepBreaker::StartBlock(MachineBasicBlock *BB) {
   assert(!State);
   State = new AggressiveAntiDepState(TRI->getNumRegs(), BB);
 
-  bool IsReturnBlock = (!BB->empty() && BB->back().isReturn());
+  bool IsReturnBlock = BB->isReturnBlock();
   std::vector<unsigned> &KillIndices = State->GetKillIndices();
   std::vector<unsigned> &DefIndices = State->GetDefIndices();
 

llvm/lib/CodeGen/CriticalAntiDepBreaker.cpp

@@ -52,7 +52,7 @@ void CriticalAntiDepBreaker::StartBlock(MachineBasicBlock *BB) {
   // Clear "do not change" set.
   KeepRegs.reset();
 
-  bool IsReturnBlock = (BBSize != 0 && BB->back().isReturn());
+  bool IsReturnBlock = BB->isReturnBlock();
 
   // Examine the live-in regs of all successors.
   for (MachineBasicBlock::succ_iterator SI = BB->succ_begin(),

llvm/lib/CodeGen/PrologEpilogInserter.cpp

@@ -92,9 +92,6 @@ private:
                            int &SPAdj);
   void scavengeFrameVirtualRegs(MachineFunction &Fn);
   void insertPrologEpilogCode(MachineFunction &Fn);
-
-  // Convenience for recognizing return blocks.
-  bool isReturnBlock(const MachineBasicBlock *MBB) const;
 };
 } // namespace
 
@@ -129,10 +126,6 @@ void PEI::getAnalysisUsage(AnalysisUsage &AU) const {
   MachineFunctionPass::getAnalysisUsage(AU);
 }
 
-bool PEI::isReturnBlock(const MachineBasicBlock* MBB) const {
-  return (MBB && !MBB->empty() && MBB->back().isReturn());
-}
-
 /// Compute the set of return blocks
 void PEI::calculateSets(MachineFunction &Fn) {
   const MachineFrameInfo *MFI = Fn.getFrameInfo();
@@ -149,7 +142,7 @@ void PEI::calculateSets(MachineFunction &Fn) {
     // If RestoreBlock does not have any successor and is not a return block
     // then the end point is unreachable and we do not need to insert any
     // epilogue.
-    if (!RestoreBlock->succ_empty() || isReturnBlock(RestoreBlock))
+    if (!RestoreBlock->succ_empty() || RestoreBlock->isReturnBlock())
       RestoreBlocks.push_back(RestoreBlock);
     return;
   }
@@ -159,7 +152,7 @@ void PEI::calculateSets(MachineFunction &Fn) {
   for (MachineBasicBlock &MBB : Fn) {
     if (MBB.isEHFuncletEntry())
       SaveBlocks.push_back(&MBB);
-    if (isReturnBlock(&MBB))
+    if (MBB.isReturnBlock())
       RestoreBlocks.push_back(&MBB);
   }
 }

llvm/lib/Target/Hexagon/HexagonFrameLowering.cpp

@@ -370,11 +370,11 @@ void HexagonFrameLowering::emitPrologue(MachineFunction &MF,
     insertEpilogueInBlock(*EpilogB);
   } else {
     for (auto &B : MF)
-      if (!B.empty() && B.back().isReturn())
+      if (B.isReturnBlock())
         insertCSRRestoresInBlock(B, CSI, HRI);
 
     for (auto &B : MF)
-      if (!B.empty() && B.back().isReturn())
+      if (B.isReturnBlock())
         insertEpilogueInBlock(B);
   }
 }

llvm/lib/Target/NVPTX/NVPTXPrologEpilogPass.cpp

@@ -72,7 +72,7 @@ bool NVPTXPrologEpilogPass::runOnMachineFunction(MachineFunction &MF) {
 
   for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) {
     // If last instruction is a return instruction, add an epilogue
-    if (!I->empty() && I->back().isReturn())
+    if (I->isReturnBlock())
       TFI.emitEpilogue(MF, *I);
   }
 

llvm/lib/Target/PowerPC/PPCFrameLowering.cpp

@@ -270,7 +270,7 @@ static void RemoveVRSaveCode(MachineInstr *MI) {
   // epilog blocks.
   for (MachineFunction::iterator I = MF->begin(), E = MF->end(); I != E; ++I) {
     // If last instruction is a return instruction, add an epilogue
-    if (!I->empty() && I->back().isReturn()) {
+    if (I->isReturnBlock()) {
       bool FoundIt = false;
       for (MBBI = I->end(); MBBI != I->begin(); ) {
         --MBBI;
@@ -326,7 +326,7 @@ static void HandleVRSaveUpdate(MachineInstr *MI, const TargetInstrInfo &TII) {
   for (MachineFunction::const_iterator BI = MF->begin(), BE = MF->end();
        UsedRegMask != 0 && BI != BE; ++BI) {
     const MachineBasicBlock &MBB = *BI;
-    if (MBB.empty() || !MBB.back().isReturn())
+    if (!MBB.isReturnBlock())
       continue;
     const MachineInstr &Ret = MBB.back();
     for (unsigned I = 0, E = Ret.getNumOperands(); I != E; ++I) {

llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp

@@ -286,7 +286,7 @@ void PPCDAGToDAGISel::InsertVRSaveCode(MachineFunction &Fn) {
 
   // Find all return blocks, outputting a restore in each epilog.
   for (MachineFunction::iterator BB = Fn.begin(), E = Fn.end(); BB != E; ++BB) {
-    if (!BB->empty() && BB->back().isReturn()) {
+    if (BB->isReturnBlock()) {
       IP = BB->end(); --IP;
 
       // Skip over all terminator instructions, which are part of the return