[NFC] Add `push_back` to `llvm::Function`

[etcwilde]

Summary

Appending a basic block to a function is a fairly common operation. The basic block list is private now, so pushing back is currently done by myFunction->insert(myFunction->getEnd(), bb);, which feels a bit redundant. This patch adds a push_back convenience function to llvm::Function to make appending basic blocks a bit easier again.

+  /// append \p BB to the end of the function
+  void push_back(BasicBlock *BB) {
+    return BasicBlocks.push_back(BB);
+  }

I've also gone through and migrated the usage in kaleidoscope, the getting started docs, and in clang where I saw it.
I'm open to leaving that part of the change off, but it makes it a little bit clearer what the intended goal is.

I was going back and forth a little regarding the naming. appendBasicBlock is clearest, push_back is most consistent though.

[etcwilde]

Fixing push_back formatting.

[etcwilde]

Failure was a formatting issue in clang/lib/Analysis/UnsafeBufferUsage.cpp.
I just fixed that in d7b45945fbb7c4ac27c456dd7c2ff8bb40fcf8f8.
I don't know how to re-trigger the tests though.

clang/lib/CodeGen/CGStmt.cpp

if (IsFinished && BB->use_empty()) {
     return;
   }
 
   // Place the block after the current block, if possible, or else at
   // the end of the function.
   if (CurBB && CurBB->getParent())
     CurFn->insert(std::next(CurBB->getIterator()), BB);
   else
-    CurFn->insert(CurFn->end(), BB);
+    CurFn->push_back(BB);
   Builder.SetInsertPoint(BB);
 }
 
 void CodeGenFunction::EmitBranch(llvm::BasicBlock *Target) {
   // Emit a branch from the current block to the target one if this
   // was a real block.  If this was just a fall-through block after a
   // terminator, don't emit it.
   llvm::BasicBlock *CurBB = Builder.GetInsertBlock();
for (llvm::User *u : block->users()) {
     if (llvm::Instruction *insn = dyn_cast<llvm::Instruction>(u)) {
       CurFn->insert(std::next(insn->getParent()->getIterator()), block);
       inserted = true;
       break;
     }
   }
 
   if (!inserted)
-    CurFn->insert(CurFn->end(), block);
+    CurFn->push_back(block);
 
   Builder.SetInsertPoint(block);
 }
 
 CodeGenFunction::JumpDest
 CodeGenFunction::getJumpDestForLabel(const LabelDecl *D) {
   JumpDest &Dest = LabelMap[D];
   if (Dest.isValid()) return Dest;
void CodeGenFunction::EmitCaseStmtRange(const CaseStmt &S,
   llvm::BasicBlock *RestoreBB = Builder.GetInsertBlock();
 
   // Push this test onto the chain of range checks (which terminates
   // in the default basic block). The switch's default will be changed
   // to the top of this chain after switch emission is complete.
   llvm::BasicBlock *FalseDest = CaseRangeBlock;
   CaseRangeBlock = createBasicBlock("sw.caserange");
 
-  CurFn->insert(CurFn->end(), CaseRangeBlock);
+  CurFn->push_back(CaseRangeBlock);
   Builder.SetInsertPoint(CaseRangeBlock);
 
   // Emit range check.
   llvm::Value *Diff =
     Builder.CreateSub(SwitchInsn->getCondition(), Builder.getInt(LHS));
   llvm::Value *Cond =
     Builder.CreateICmpULE(Diff, Builder.getInt(Range), "inbounds");
 

clang/lib/CodeGen/CodeGenFunction.cpp

llvm::DebugLoc CodeGenFunction::EmitReturnBlock() {
 
   EmitBlock(ReturnBlock.getBlock());
   return llvm::DebugLoc();
 }
 
 static void EmitIfUsed(CodeGenFunction &CGF, llvm::BasicBlock *BB) {
   if (!BB) return;
   if (!BB->use_empty()) {
-    CGF.CurFn->insert(CGF.CurFn->end(), BB);
+    CGF.CurFn->push_back(BB);
     return;
   }
   delete BB;
 }
 
 void CodeGenFunction::FinishFunction(SourceLocation EndLoc) {
   assert(BreakContinueStack.empty() &&
          "mismatched push/pop in break/continue stack!");

llvm/docs/tutorial/MyFirstLanguageFrontend/LangImpl05.rst

 emitting into if, for example, it contains a nested "if/then/else"
 expression. Because calling ``codegen()`` recursively could arbitrarily change
 the notion of the current block, we are required to get an up-to-date
 value for code that will set up the Phi node.
 
 .. code-block:: c++
 
       // Emit else block.
-      TheFunction->insert(TheFunction->end(), ElseBB);
+      TheFunction->push_back(ElseBB);
       Builder->SetInsertPoint(ElseBB);
 
       Value *ElseV = Else->codegen();
       if (!ElseV)
         return nullptr;
 
       Builder->CreateBr(MergeBB);
       // codegen of 'Else' can change the current block, update ElseBB for the PHI.
       ElseBB = Builder->GetInsertBlock();
 
 Code generation for the 'else' block is basically identical to codegen
 for the 'then' block. The only significant difference is the first line,
 which adds the 'else' block to the function. Recall previously that the
 'else' block was created, but not added to the function. Now that the
 'then' and 'else' blocks are emitted, we can finish up with the merge
 code:
 
 .. code-block:: c++
 
       // Emit merge block.
-      TheFunction->insert(TheFunction->end(), MergeBB);
+      TheFunction->push_back(MergeBB);
       Builder->SetInsertPoint(MergeBB);
       PHINode *PN =
         Builder->CreatePHI(Type::getDoubleTy(*TheContext), 2, "iftmp");
 
       PN->addIncoming(ThenV, ThenBB);
       PN->addIncoming(ElseV, ElseBB);
       return PN;
     }

llvm/examples/Kaleidoscope/BuildingAJIT/Chapter1/toy.cpp

Value *IfExprAST::codegen() {
   if (!ThenV)
     return nullptr;
 
   Builder->CreateBr(MergeBB);
   // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
   ThenBB = Builder->GetInsertBlock();
 
   // Emit else block.
-  TheFunction->insert(TheFunction->end(), ElseBB);
+  TheFunction->push_back(ElseBB);
   Builder->SetInsertPoint(ElseBB);
 
   Value *ElseV = Else->codegen();
   if (!ElseV)
     return nullptr;
 
   Builder->CreateBr(MergeBB);
   // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
   ElseBB = Builder->GetInsertBlock();
 
   // Emit merge block.
-  TheFunction->insert(TheFunction->end(), MergeBB);
+  TheFunction->push_back(MergeBB);
   Builder->SetInsertPoint(MergeBB);
   PHINode *PN = Builder->CreatePHI(Type::getDoubleTy(*TheContext), 2, "iftmp");
 
   PN->addIncoming(ThenV, ThenBB);
   PN->addIncoming(ElseV, ElseBB);
   return PN;
 }
 

llvm/examples/Kaleidoscope/BuildingAJIT/Chapter2/toy.cpp

Value *IfExprAST::codegen() {
   if (!ThenV)
     return nullptr;
 
   Builder->CreateBr(MergeBB);
   // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
   ThenBB = Builder->GetInsertBlock();
 
   // Emit else block.
-  TheFunction->insert(TheFunction->end(), ElseBB);
+  TheFunction->push_back(ElseBB);
   Builder->SetInsertPoint(ElseBB);
 
   Value *ElseV = Else->codegen();
   if (!ElseV)
     return nullptr;
 
   Builder->CreateBr(MergeBB);
   // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
   ElseBB = Builder->GetInsertBlock();
 
   // Emit merge block.
-  TheFunction->insert(TheFunction->end(), MergeBB);
+  TheFunction->push_back(MergeBB);
   Builder->SetInsertPoint(MergeBB);
   PHINode *PN = Builder->CreatePHI(Type::getDoubleTy(*TheContext), 2, "iftmp");
 
   PN->addIncoming(ThenV, ThenBB);
   PN->addIncoming(ElseV, ElseBB);
   return PN;
 }
 

llvm/examples/Kaleidoscope/BuildingAJIT/Chapter3/toy.cpp

Value *IfExprAST::codegen() {
   if (!ThenV)
     return nullptr;
 
   Builder->CreateBr(MergeBB);
   // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
   ThenBB = Builder->GetInsertBlock();
 
   // Emit else block.
-  TheFunction->insert(TheFunction->end(), ElseBB);
+  TheFunction->push_back(ElseBB);
   Builder->SetInsertPoint(ElseBB);
 
   Value *ElseV = Else->codegen();
   if (!ElseV)
     return nullptr;
 
   Builder->CreateBr(MergeBB);
   // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
   ElseBB = Builder->GetInsertBlock();
 
   // Emit merge block.
-  TheFunction->insert(TheFunction->end(), MergeBB);
+  TheFunction->push_back(MergeBB);
   Builder->SetInsertPoint(MergeBB);
   PHINode *PN = Builder->CreatePHI(Type::getDoubleTy(*TheContext), 2, "iftmp");
 
   PN->addIncoming(ThenV, ThenBB);
   PN->addIncoming(ElseV, ElseBB);
   return PN;
 }
 

llvm/examples/Kaleidoscope/BuildingAJIT/Chapter4/toy.cpp

Value *IfExprAST::codegen() {
   if (!ThenV)
     return nullptr;
 
   Builder->CreateBr(MergeBB);
   // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
   ThenBB = Builder->GetInsertBlock();
 
   // Emit else block.
-  TheFunction->insert(TheFunction->end(), ElseBB);
+  TheFunction->push_back(ElseBB);
   Builder->SetInsertPoint(ElseBB);
 
   Value *ElseV = Else->codegen();
   if (!ElseV)
     return nullptr;
 
   Builder->CreateBr(MergeBB);
   // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
   ElseBB = Builder->GetInsertBlock();
 
   // Emit merge block.
-  TheFunction->insert(TheFunction->end(), MergeBB);
+  TheFunction->push_back(MergeBB);
   Builder->SetInsertPoint(MergeBB);
   PHINode *PN = Builder->CreatePHI(Type::getDoubleTy(*TheContext), 2, "iftmp");
 
   PN->addIncoming(ThenV, ThenBB);
   PN->addIncoming(ElseV, ElseBB);
   return PN;
 }
 

llvm/examples/Kaleidoscope/Chapter5/toy.cpp

Value *IfExprAST::codegen() {
   if (!ThenV)
     return nullptr;
 
   Builder->CreateBr(MergeBB);
   // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
   ThenBB = Builder->GetInsertBlock();
 
   // Emit else block.
-  TheFunction->insert(TheFunction->end(), ElseBB);
+  TheFunction->push_back(ElseBB);
   Builder->SetInsertPoint(ElseBB);
 
   Value *ElseV = Else->codegen();
   if (!ElseV)
     return nullptr;
 
   Builder->CreateBr(MergeBB);
   // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
   ElseBB = Builder->GetInsertBlock();
 
   // Emit merge block.
-  TheFunction->insert(TheFunction->end(), MergeBB);
+  TheFunction->push_back(MergeBB);
   Builder->SetInsertPoint(MergeBB);
   PHINode *PN = Builder->CreatePHI(Type::getDoubleTy(*TheContext), 2, "iftmp");
 
   PN->addIncoming(ThenV, ThenBB);
   PN->addIncoming(ElseV, ElseBB);
   return PN;
 }
 

llvm/examples/Kaleidoscope/Chapter6/toy.cpp

Value *IfExprAST::codegen() {
   if (!ThenV)
     return nullptr;
 
   Builder->CreateBr(MergeBB);
   // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
   ThenBB = Builder->GetInsertBlock();
 
   // Emit else block.
-  TheFunction->insert(TheFunction->end(), ElseBB);
+  TheFunction->push_back(ElseBB);
   Builder->SetInsertPoint(ElseBB);
 
   Value *ElseV = Else->codegen();
   if (!ElseV)
     return nullptr;
 
   Builder->CreateBr(MergeBB);
   // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
   ElseBB = Builder->GetInsertBlock();
 
   // Emit merge block.
-  TheFunction->insert(TheFunction->end(), MergeBB);
+  TheFunction->push_back(MergeBB);
   Builder->SetInsertPoint(MergeBB);
   PHINode *PN = Builder->CreatePHI(Type::getDoubleTy(*TheContext), 2, "iftmp");
 
   PN->addIncoming(ThenV, ThenBB);
   PN->addIncoming(ElseV, ElseBB);
   return PN;
 }
 

llvm/examples/Kaleidoscope/Chapter7/toy.cpp

Value *IfExprAST::codegen() {
   if (!ThenV)
     return nullptr;
 
   Builder->CreateBr(MergeBB);
   // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
   ThenBB = Builder->GetInsertBlock();
 
   // Emit else block.
-  TheFunction->insert(TheFunction->end(), ElseBB);
+  TheFunction->push_back(ElseBB);
   Builder->SetInsertPoint(ElseBB);
 
   Value *ElseV = Else->codegen();
   if (!ElseV)
     return nullptr;
 
   Builder->CreateBr(MergeBB);
   // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
   ElseBB = Builder->GetInsertBlock();
 
   // Emit merge block.
-  TheFunction->insert(TheFunction->end(), MergeBB);
+  TheFunction->push_back(MergeBB);
   Builder->SetInsertPoint(MergeBB);
   PHINode *PN = Builder->CreatePHI(Type::getDoubleTy(*TheContext), 2, "iftmp");
 
   PN->addIncoming(ThenV, ThenBB);
   PN->addIncoming(ElseV, ElseBB);
   return PN;
 }
 

llvm/examples/Kaleidoscope/Chapter8/toy.cpp

Value *IfExprAST::codegen() {
   if (!ThenV)
     return nullptr;
 
   Builder->CreateBr(MergeBB);
   // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
   ThenBB = Builder->GetInsertBlock();
 
   // Emit else block.
-  TheFunction->insert(TheFunction->end(), ElseBB);
+  TheFunction->push_back(ElseBB);
   Builder->SetInsertPoint(ElseBB);
 
   Value *ElseV = Else->codegen();
   if (!ElseV)
     return nullptr;
 
   Builder->CreateBr(MergeBB);
   // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
   ElseBB = Builder->GetInsertBlock();
 
   // Emit merge block.
-  TheFunction->insert(TheFunction->end(), MergeBB);
+  TheFunction->push_back(MergeBB);
   Builder->SetInsertPoint(MergeBB);
   PHINode *PN = Builder->CreatePHI(Type::getDoubleTy(*TheContext), 2, "iftmp");
 
   PN->addIncoming(ThenV, ThenBB);
   PN->addIncoming(ElseV, ElseBB);
   return PN;
 }
 

llvm/examples/Kaleidoscope/Chapter9/toy.cpp

   if (!ThenV)
     return nullptr;
 
   Builder->CreateBr(MergeBB);
   // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
   ThenBB = Builder->GetInsertBlock();
 
   // Emit else block.
-  TheFunction->insert(TheFunction->end(), ElseBB);
+  TheFunction->push_back(ElseBB);
   Builder->SetInsertPoint(ElseBB);
 
   Value *ElseV = Else->codegen();
   if (!ElseV)
     return nullptr;
 
   Builder->CreateBr(MergeBB);
   // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
   ElseBB = Builder->GetInsertBlock();
 
   // Emit merge block.
-  TheFunction->insert(TheFunction->end(), MergeBB);
+  TheFunction->push_back(MergeBB);
   Builder->SetInsertPoint(MergeBB);
   PHINode *PN = Builder->CreatePHI(Type::getDoubleTy(*TheContext), 2, "iftmp");
 
   PN->addIncoming(ThenV, ThenBB);
   PN->addIncoming(ElseV, ElseBB);
   return PN;
 }
 

llvm/examples/Kaleidoscope/MCJIT/cached/toy-jit.cpp

Value *IfExprAST::Codegen() {
   Value *ThenV = Then->Codegen();
   if (ThenV == 0) return 0;
   
   Builder.CreateBr(MergeBB);
   // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
   ThenBB = Builder.GetInsertBlock();
   
   // Emit else block.
-  TheFunction->insert(TheFunction->end(), ElseBB);
+  TheFunction->push_back(ElseBB);
   Builder.SetInsertPoint(ElseBB);
   
   Value *ElseV = Else->Codegen();
   if (ElseV == 0) return 0;
   
   Builder.CreateBr(MergeBB);
   // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
   ElseBB = Builder.GetInsertBlock();
   
   // Emit merge block.
-  TheFunction->insert(TheFunction->end(), MergeBB);
+  TheFunction->push_back(MergeBB);
   Builder.SetInsertPoint(MergeBB);
   PHINode *PN = Builder.CreatePHI(Type::getDoubleTy(TheContext), 2, "iftmp");
 
   PN->addIncoming(ThenV, ThenBB);
   PN->addIncoming(ElseV, ElseBB);
   return PN;
 }
 

llvm/examples/Kaleidoscope/MCJIT/cached/toy.cpp

   Value *ThenV = Then->Codegen();
   if (ThenV == 0) return 0;
 
   Builder.CreateBr(MergeBB);
   // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
   ThenBB = Builder.GetInsertBlock();
 
   // Emit else block.
-  TheFunction->insert(TheFunction->end(), ElseBB);
+  TheFunction->push_back(ElseBB);
   Builder.SetInsertPoint(ElseBB);
 
   Value *ElseV = Else->Codegen();
   if (ElseV == 0) return 0;
 
   Builder.CreateBr(MergeBB);
   // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
   ElseBB = Builder.GetInsertBlock();
 
   // Emit merge block.
-  TheFunction->insert(TheFunction->end(), MergeBB);
+  TheFunction->push_back(MergeBB);
   Builder.SetInsertPoint(MergeBB);
   PHINode *PN = Builder.CreatePHI(Type::getDoubleTy(TheContext), 2, "iftmp");
 
   PN->addIncoming(ThenV, ThenBB);
   PN->addIncoming(ElseV, ElseBB);
   return PN;
 }
 

llvm/examples/Kaleidoscope/MCJIT/complete/toy.cpp

   Value *ThenV = Then->Codegen();
   if (ThenV == 0) return 0;
 
   Builder.CreateBr(MergeBB);
   // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
   ThenBB = Builder.GetInsertBlock();
 
   // Emit else block.
-  TheFunction->insert(TheFunction->end(), ElseBB);
+  TheFunction->push_back(ElseBB);
   Builder.SetInsertPoint(ElseBB);
 
   Value *ElseV = Else->Codegen();
   if (ElseV == 0) return 0;
 
   Builder.CreateBr(MergeBB);
   // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
   ElseBB = Builder.GetInsertBlock();
 
   // Emit merge block.
-  TheFunction->insert(TheFunction->end(), MergeBB);
+  TheFunction->push_back(MergeBB);
   Builder.SetInsertPoint(MergeBB);
   PHINode *PN = Builder.CreatePHI(Type::getDoubleTy(TheContext), 2, "iftmp");
 
   PN->addIncoming(ThenV, ThenBB);
   PN->addIncoming(ElseV, ElseBB);
   return PN;
 }
 

llvm/examples/Kaleidoscope/MCJIT/initial/toy.cpp

Value *IfExprAST::Codegen() {
   Value *ThenV = Then->Codegen();
   if (ThenV == 0) return 0;
 
   Builder.CreateBr(MergeBB);
   // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
   ThenBB = Builder.GetInsertBlock();
 
   // Emit else block.
-  TheFunction->insert(TheFunction->end(), ElseBB);
+  TheFunction->push_back(ElseBB);
   Builder.SetInsertPoint(ElseBB);
 
   Value *ElseV = Else->Codegen();
   if (ElseV == 0) return 0;
 
   Builder.CreateBr(MergeBB);
   // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
   ElseBB = Builder.GetInsertBlock();
 
   // Emit merge block.
-  TheFunction->insert(TheFunction->end(), MergeBB);
+  TheFunction->push_back(MergeBB);
   Builder.SetInsertPoint(MergeBB);
   PHINode *PN = Builder.CreatePHI(Type::getDoubleTy(TheContext), 2, "iftmp");
 
   PN->addIncoming(ThenV, ThenBB);
   PN->addIncoming(ElseV, ElseBB);
   return PN;
 }
 

llvm/examples/Kaleidoscope/MCJIT/lazy/toy-jit.cpp

Value *IfExprAST::Codegen() {
   Value *ThenV = Then->Codegen();
   if (ThenV == 0) return 0;
   
   Builder.CreateBr(MergeBB);
   // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
   ThenBB = Builder.GetInsertBlock();
   
   // Emit else block.
-  TheFunction->insert(TheFunction->end(), ElseBB);
+  TheFunction->push_back(ElseBB);
   Builder.SetInsertPoint(ElseBB);
   
   Value *ElseV = Else->Codegen();
   if (ElseV == 0) return 0;
   
   Builder.CreateBr(MergeBB);
   // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
   ElseBB = Builder.GetInsertBlock();
   
   // Emit merge block.
-  TheFunction->insert(TheFunction->end(), MergeBB);
+  TheFunction->push_back(MergeBB);
   Builder.SetInsertPoint(MergeBB);
   PHINode *PN = Builder.CreatePHI(Type::getDoubleTy(TheContext), 2, "iftmp");
 
   PN->addIncoming(ThenV, ThenBB);
   PN->addIncoming(ElseV, ElseBB);
   return PN;
 }
 

llvm/examples/Kaleidoscope/MCJIT/lazy/toy.cpp

   Value *ThenV = Then->Codegen();
   if (ThenV == 0) return 0;
 
   Builder.CreateBr(MergeBB);
   // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
   ThenBB = Builder.GetInsertBlock();
 
   // Emit else block.
-  TheFunction->insert(TheFunction->end(), ElseBB);
+  TheFunction->push_back(ElseBB);
   Builder.SetInsertPoint(ElseBB);
 
   Value *ElseV = Else->Codegen();
   if (ElseV == 0) return 0;
 
   Builder.CreateBr(MergeBB);
   // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
   ElseBB = Builder.GetInsertBlock();
 
   // Emit merge block.
-  TheFunction->insert(TheFunction->end(), MergeBB);
+  TheFunction->push_back(MergeBB);
   Builder.SetInsertPoint(MergeBB);
   PHINode *PN = Builder.CreatePHI(Type::getDoubleTy(TheContext), 2, "iftmp");
 
   PN->addIncoming(ThenV, ThenBB);
   PN->addIncoming(ElseV, ElseBB);
   return PN;
 }
 

llvm/include/llvm/IR/Function.h

public:
   void stealArgumentListFrom(Function &Src);
 
   /// Insert \p BB in the basic block list at \p Position. \Returns an iterator
   /// to the newly inserted BB.
   Function::iterator insert(Function::iterator Position, BasicBlock *BB) {
     return BasicBlocks.insert(Position, BB);
   }
 
+  /// append \p BB to the end of the function
+  void push_back(BasicBlock *BB) { return BasicBlocks.push_back(BB); }
+
   /// Transfer all blocks from \p FromF to this function at \p ToIt.
   void splice(Function::iterator ToIt, Function *FromF) {
     splice(ToIt, FromF, FromF->begin(), FromF->end());
   }
 
   /// Transfer one BasicBlock from \p FromF at \p FromIt to this function
   /// at \p ToIt.
   void splice(Function::iterator ToIt, Function *FromF,