1 //===- InlineFunction.cpp - Code to perform function inlining -------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements inlining of a function into a call site, resolving
11 // parameters and the return value as appropriate.
13 //===----------------------------------------------------------------------===//
15 #include "llvm/Transforms/Utils/Cloning.h"
16 #include "llvm/Constants.h"
17 #include "llvm/DerivedTypes.h"
18 #include "llvm/Module.h"
19 #include "llvm/Instructions.h"
20 #include "llvm/Intrinsics.h"
21 #include "llvm/ParameterAttributes.h"
22 #include "llvm/Analysis/CallGraph.h"
23 #include "llvm/Target/TargetData.h"
24 #include "llvm/ADT/SmallVector.h"
25 #include "llvm/ADT/StringExtras.h"
26 #include "llvm/Support/CallSite.h"
29 bool llvm::InlineFunction(CallInst *CI, CallGraph *CG, const TargetData *TD) {
30 return InlineFunction(CallSite(CI), CG, TD);
32 bool llvm::InlineFunction(InvokeInst *II, CallGraph *CG, const TargetData *TD) {
33 return InlineFunction(CallSite(II), CG, TD);
36 /// HandleInlinedInvoke - If we inlined an invoke site, we need to convert calls
37 /// in the body of the inlined function into invokes and turn unwind
38 /// instructions into branches to the invoke unwind dest.
40 /// II is the invoke instruction begin inlined. FirstNewBlock is the first
41 /// block of the inlined code (the last block is the end of the function),
42 /// and InlineCodeInfo is information about the code that got inlined.
43 static void HandleInlinedInvoke(InvokeInst *II, BasicBlock *FirstNewBlock,
44 ClonedCodeInfo &InlinedCodeInfo) {
45 BasicBlock *InvokeDest = II->getUnwindDest();
46 std::vector<Value*> InvokeDestPHIValues;
48 // If there are PHI nodes in the unwind destination block, we need to
49 // keep track of which values came into them from this invoke, then remove
50 // the entry for this block.
51 BasicBlock *InvokeBlock = II->getParent();
52 for (BasicBlock::iterator I = InvokeDest->begin(); isa<PHINode>(I); ++I) {
53 PHINode *PN = cast<PHINode>(I);
54 // Save the value to use for this edge.
55 InvokeDestPHIValues.push_back(PN->getIncomingValueForBlock(InvokeBlock));
58 Function *Caller = FirstNewBlock->getParent();
60 // The inlined code is currently at the end of the function, scan from the
61 // start of the inlined code to its end, checking for stuff we need to
63 if (InlinedCodeInfo.ContainsCalls || InlinedCodeInfo.ContainsUnwinds) {
64 for (Function::iterator BB = FirstNewBlock, E = Caller->end();
66 if (InlinedCodeInfo.ContainsCalls) {
67 for (BasicBlock::iterator BBI = BB->begin(), E = BB->end(); BBI != E; ){
68 Instruction *I = BBI++;
70 // We only need to check for function calls: inlined invoke
71 // instructions require no special handling.
72 if (!isa<CallInst>(I)) continue;
73 CallInst *CI = cast<CallInst>(I);
75 // If this call cannot unwind, don't convert it to an invoke.
76 if (CI->doesNotThrow())
79 // Convert this function call into an invoke instruction.
80 // First, split the basic block.
81 BasicBlock *Split = BB->splitBasicBlock(CI, CI->getName()+".noexc");
83 // Next, create the new invoke instruction, inserting it at the end
84 // of the old basic block.
85 SmallVector<Value*, 8> InvokeArgs(CI->op_begin()+1, CI->op_end());
87 InvokeInst::Create(CI->getCalledValue(), Split, InvokeDest,
88 InvokeArgs.begin(), InvokeArgs.end(),
89 CI->getName(), BB->getTerminator());
90 II->setCallingConv(CI->getCallingConv());
91 II->setParamAttrs(CI->getParamAttrs());
93 // Make sure that anything using the call now uses the invoke!
94 CI->replaceAllUsesWith(II);
96 // Delete the unconditional branch inserted by splitBasicBlock
97 BB->getInstList().pop_back();
98 Split->getInstList().pop_front(); // Delete the original call
100 // Update any PHI nodes in the exceptional block to indicate that
101 // there is now a new entry in them.
103 for (BasicBlock::iterator I = InvokeDest->begin();
104 isa<PHINode>(I); ++I, ++i) {
105 PHINode *PN = cast<PHINode>(I);
106 PN->addIncoming(InvokeDestPHIValues[i], BB);
109 // This basic block is now complete, start scanning the next one.
114 if (UnwindInst *UI = dyn_cast<UnwindInst>(BB->getTerminator())) {
115 // An UnwindInst requires special handling when it gets inlined into an
116 // invoke site. Once this happens, we know that the unwind would cause
117 // a control transfer to the invoke exception destination, so we can
118 // transform it into a direct branch to the exception destination.
119 BranchInst::Create(InvokeDest, UI);
121 // Delete the unwind instruction!
122 UI->getParent()->getInstList().pop_back();
124 // Update any PHI nodes in the exceptional block to indicate that
125 // there is now a new entry in them.
127 for (BasicBlock::iterator I = InvokeDest->begin();
128 isa<PHINode>(I); ++I, ++i) {
129 PHINode *PN = cast<PHINode>(I);
130 PN->addIncoming(InvokeDestPHIValues[i], BB);
136 // Now that everything is happy, we have one final detail. The PHI nodes in
137 // the exception destination block still have entries due to the original
138 // invoke instruction. Eliminate these entries (which might even delete the
140 InvokeDest->removePredecessor(II->getParent());
143 /// UpdateCallGraphAfterInlining - Once we have cloned code over from a callee
144 /// into the caller, update the specified callgraph to reflect the changes we
145 /// made. Note that it's possible that not all code was copied over, so only
146 /// some edges of the callgraph will be remain.
147 static void UpdateCallGraphAfterInlining(const Function *Caller,
148 const Function *Callee,
149 Function::iterator FirstNewBlock,
150 DenseMap<const Value*, Value*> &ValueMap,
152 // Update the call graph by deleting the edge from Callee to Caller
153 CallGraphNode *CalleeNode = CG[Callee];
154 CallGraphNode *CallerNode = CG[Caller];
155 CallerNode->removeCallEdgeTo(CalleeNode);
157 // Since we inlined some uninlined call sites in the callee into the caller,
158 // add edges from the caller to all of the callees of the callee.
159 for (CallGraphNode::iterator I = CalleeNode->begin(),
160 E = CalleeNode->end(); I != E; ++I) {
161 const Instruction *OrigCall = I->first.getInstruction();
163 DenseMap<const Value*, Value*>::iterator VMI = ValueMap.find(OrigCall);
164 // Only copy the edge if the call was inlined!
165 if (VMI != ValueMap.end() && VMI->second) {
166 // If the call was inlined, but then constant folded, there is no edge to
167 // add. Check for this case.
168 if (Instruction *NewCall = dyn_cast<Instruction>(VMI->second))
169 CallerNode->addCalledFunction(CallSite::get(NewCall), I->second);
175 // InlineFunction - This function inlines the called function into the basic
176 // block of the caller. This returns false if it is not possible to inline this
177 // call. The program is still in a well defined state if this occurs though.
179 // Note that this only does one level of inlining. For example, if the
180 // instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now
181 // exists in the instruction stream. Similiarly this will inline a recursive
182 // function by one level.
184 bool llvm::InlineFunction(CallSite CS, CallGraph *CG, const TargetData *TD) {
185 Instruction *TheCall = CS.getInstruction();
186 assert(TheCall->getParent() && TheCall->getParent()->getParent() &&
187 "Instruction not in function!");
189 const Function *CalledFunc = CS.getCalledFunction();
190 if (CalledFunc == 0 || // Can't inline external function or indirect
191 CalledFunc->isDeclaration() || // call, or call to a vararg function!
192 CalledFunc->getFunctionType()->isVarArg()) return false;
195 // If the call to the callee is a non-tail call, we must clear the 'tail'
196 // flags on any calls that we inline.
197 bool MustClearTailCallFlags =
198 isa<CallInst>(TheCall) && !cast<CallInst>(TheCall)->isTailCall();
200 // If the call to the callee cannot throw, set the 'nounwind' flag on any
201 // calls that we inline.
202 bool MarkNoUnwind = CS.doesNotThrow();
204 BasicBlock *OrigBB = TheCall->getParent();
205 Function *Caller = OrigBB->getParent();
207 // GC poses two hazards to inlining, which only occur when the callee has GC:
208 // 1. If the caller has no GC, then the callee's GC must be propagated to the
210 // 2. If the caller has a differing GC, it is invalid to inline.
211 if (CalledFunc->hasCollector()) {
212 if (!Caller->hasCollector())
213 Caller->setCollector(CalledFunc->getCollector());
214 else if (CalledFunc->getCollector() != Caller->getCollector())
218 // Get an iterator to the last basic block in the function, which will have
219 // the new function inlined after it.
221 Function::iterator LastBlock = &Caller->back();
223 // Make sure to capture all of the return instructions from the cloned
225 std::vector<ReturnInst*> Returns;
226 ClonedCodeInfo InlinedFunctionInfo;
227 Function::iterator FirstNewBlock;
229 { // Scope to destroy ValueMap after cloning.
230 DenseMap<const Value*, Value*> ValueMap;
232 assert(std::distance(CalledFunc->arg_begin(), CalledFunc->arg_end()) ==
233 std::distance(CS.arg_begin(), CS.arg_end()) &&
234 "No varargs calls can be inlined!");
236 // Calculate the vector of arguments to pass into the function cloner, which
237 // matches up the formal to the actual argument values.
238 CallSite::arg_iterator AI = CS.arg_begin();
240 for (Function::const_arg_iterator I = CalledFunc->arg_begin(),
241 E = CalledFunc->arg_end(); I != E; ++I, ++AI, ++ArgNo) {
242 Value *ActualArg = *AI;
244 // When byval arguments actually inlined, we need to make the copy implied
245 // by them explicit. However, we don't do this if the callee is readonly
246 // or readnone, because the copy would be unneeded: the callee doesn't
247 // modify the struct.
248 if (CalledFunc->paramHasAttr(ArgNo+1, ParamAttr::ByVal) &&
249 !CalledFunc->onlyReadsMemory()) {
250 const Type *AggTy = cast<PointerType>(I->getType())->getElementType();
251 const Type *VoidPtrTy = PointerType::getUnqual(Type::Int8Ty);
253 // Create the alloca. If we have TargetData, use nice alignment.
255 if (TD) Align = TD->getPrefTypeAlignment(AggTy);
256 Value *NewAlloca = new AllocaInst(AggTy, 0, Align, I->getName(),
257 Caller->begin()->begin());
259 Function *MemCpyFn = Intrinsic::getDeclaration(Caller->getParent(),
260 Intrinsic::memcpy_i64);
261 Value *DestCast = new BitCastInst(NewAlloca, VoidPtrTy, "tmp", TheCall);
262 Value *SrcCast = new BitCastInst(*AI, VoidPtrTy, "tmp", TheCall);
266 Size = ConstantExpr::getSizeOf(AggTy);
268 Size = ConstantInt::get(Type::Int64Ty, TD->getTypeStoreSize(AggTy));
270 // Always generate a memcpy of alignment 1 here because we don't know
271 // the alignment of the src pointer. Other optimizations can infer
273 Value *CallArgs[] = {
274 DestCast, SrcCast, Size, ConstantInt::get(Type::Int32Ty, 1)
276 CallInst *TheMemCpy =
277 CallInst::Create(MemCpyFn, CallArgs, CallArgs+4, "", TheCall);
279 // If we have a call graph, update it.
281 CallGraphNode *MemCpyCGN = CG->getOrInsertFunction(MemCpyFn);
282 CallGraphNode *CallerNode = (*CG)[Caller];
283 CallerNode->addCalledFunction(TheMemCpy, MemCpyCGN);
286 // Uses of the argument in the function should use our new alloca
288 ActualArg = NewAlloca;
291 ValueMap[I] = ActualArg;
294 // We want the inliner to prune the code as it copies. We would LOVE to
295 // have no dead or constant instructions leftover after inlining occurs
296 // (which can happen, e.g., because an argument was constant), but we'll be
297 // happy with whatever the cloner can do.
298 CloneAndPruneFunctionInto(Caller, CalledFunc, ValueMap, Returns, ".i",
299 &InlinedFunctionInfo, TD);
301 // Remember the first block that is newly cloned over.
302 FirstNewBlock = LastBlock; ++FirstNewBlock;
304 // Update the callgraph if requested.
306 UpdateCallGraphAfterInlining(Caller, CalledFunc, FirstNewBlock, ValueMap,
310 // If there are any alloca instructions in the block that used to be the entry
311 // block for the callee, move them to the entry block of the caller. First
312 // calculate which instruction they should be inserted before. We insert the
313 // instructions at the end of the current alloca list.
316 BasicBlock::iterator InsertPoint = Caller->begin()->begin();
317 for (BasicBlock::iterator I = FirstNewBlock->begin(),
318 E = FirstNewBlock->end(); I != E; )
319 if (AllocaInst *AI = dyn_cast<AllocaInst>(I++)) {
320 // If the alloca is now dead, remove it. This often occurs due to code
322 if (AI->use_empty()) {
323 AI->eraseFromParent();
327 if (isa<Constant>(AI->getArraySize())) {
328 // Scan for the block of allocas that we can move over, and move them
330 while (isa<AllocaInst>(I) &&
331 isa<Constant>(cast<AllocaInst>(I)->getArraySize()))
334 // Transfer all of the allocas over in a block. Using splice means
335 // that the instructions aren't removed from the symbol table, then
337 Caller->getEntryBlock().getInstList().splice(
339 FirstNewBlock->getInstList(),
345 // If the inlined code contained dynamic alloca instructions, wrap the inlined
346 // code with llvm.stacksave/llvm.stackrestore intrinsics.
347 if (InlinedFunctionInfo.ContainsDynamicAllocas) {
348 Module *M = Caller->getParent();
349 // Get the two intrinsics we care about.
350 Constant *StackSave, *StackRestore;
351 StackSave = Intrinsic::getDeclaration(M, Intrinsic::stacksave);
352 StackRestore = Intrinsic::getDeclaration(M, Intrinsic::stackrestore);
354 // If we are preserving the callgraph, add edges to the stacksave/restore
355 // functions for the calls we insert.
356 CallGraphNode *StackSaveCGN = 0, *StackRestoreCGN = 0, *CallerNode = 0;
358 // We know that StackSave/StackRestore are Function*'s, because they are
359 // intrinsics which must have the right types.
360 StackSaveCGN = CG->getOrInsertFunction(cast<Function>(StackSave));
361 StackRestoreCGN = CG->getOrInsertFunction(cast<Function>(StackRestore));
362 CallerNode = (*CG)[Caller];
365 // Insert the llvm.stacksave.
366 CallInst *SavedPtr = CallInst::Create(StackSave, "savedstack",
367 FirstNewBlock->begin());
368 if (CG) CallerNode->addCalledFunction(SavedPtr, StackSaveCGN);
370 // Insert a call to llvm.stackrestore before any return instructions in the
372 for (unsigned i = 0, e = Returns.size(); i != e; ++i) {
373 CallInst *CI = CallInst::Create(StackRestore, SavedPtr, "", Returns[i]);
374 if (CG) CallerNode->addCalledFunction(CI, StackRestoreCGN);
377 // Count the number of StackRestore calls we insert.
378 unsigned NumStackRestores = Returns.size();
380 // If we are inlining an invoke instruction, insert restores before each
381 // unwind. These unwinds will be rewritten into branches later.
382 if (InlinedFunctionInfo.ContainsUnwinds && isa<InvokeInst>(TheCall)) {
383 for (Function::iterator BB = FirstNewBlock, E = Caller->end();
385 if (UnwindInst *UI = dyn_cast<UnwindInst>(BB->getTerminator())) {
386 CallInst::Create(StackRestore, SavedPtr, "", UI);
392 // If we are inlining tail call instruction through a call site that isn't
393 // marked 'tail', we must remove the tail marker for any calls in the inlined
394 // code. Also, calls inlined through a 'nounwind' call site should be marked
396 if (InlinedFunctionInfo.ContainsCalls &&
397 (MustClearTailCallFlags || MarkNoUnwind)) {
398 for (Function::iterator BB = FirstNewBlock, E = Caller->end();
400 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
401 if (CallInst *CI = dyn_cast<CallInst>(I)) {
402 if (MustClearTailCallFlags)
403 CI->setTailCall(false);
405 CI->setDoesNotThrow();
409 // If we are inlining through a 'nounwind' call site then any inlined 'unwind'
410 // instructions are unreachable.
411 if (InlinedFunctionInfo.ContainsUnwinds && MarkNoUnwind)
412 for (Function::iterator BB = FirstNewBlock, E = Caller->end();
414 TerminatorInst *Term = BB->getTerminator();
415 if (isa<UnwindInst>(Term)) {
416 new UnreachableInst(Term);
417 BB->getInstList().erase(Term);
421 // If we are inlining for an invoke instruction, we must make sure to rewrite
422 // any inlined 'unwind' instructions into branches to the invoke exception
423 // destination, and call instructions into invoke instructions.
424 if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall))
425 HandleInlinedInvoke(II, FirstNewBlock, InlinedFunctionInfo);
427 // If we cloned in _exactly one_ basic block, and if that block ends in a
428 // return instruction, we splice the body of the inlined callee directly into
429 // the calling basic block.
430 if (Returns.size() == 1 && std::distance(FirstNewBlock, Caller->end()) == 1) {
431 // Move all of the instructions right before the call.
432 OrigBB->getInstList().splice(TheCall, FirstNewBlock->getInstList(),
433 FirstNewBlock->begin(), FirstNewBlock->end());
434 // Remove the cloned basic block.
435 Caller->getBasicBlockList().pop_back();
437 // If the call site was an invoke instruction, add a branch to the normal
439 if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall))
440 BranchInst::Create(II->getNormalDest(), TheCall);
442 // If the return instruction returned a value, replace uses of the call with
443 // uses of the returned value.
444 if (!TheCall->use_empty()) {
445 ReturnInst *R = Returns[0];
446 if (isa<StructType>(TheCall->getType())) {
447 // Multiple return values.
448 while (!TheCall->use_empty()) {
449 GetResultInst *GR = cast<GetResultInst>(TheCall->use_back());
450 Value *RV = R->getOperand(GR->getIndex());
451 GR->replaceAllUsesWith(RV);
452 GR->eraseFromParent();
455 TheCall->replaceAllUsesWith(R->getReturnValue());
457 // Since we are now done with the Call/Invoke, we can delete it.
458 TheCall->getParent()->getInstList().erase(TheCall);
460 // Since we are now done with the return instruction, delete it also.
461 Returns[0]->getParent()->getInstList().erase(Returns[0]);
463 // We are now done with the inlining.
467 // Otherwise, we have the normal case, of more than one block to inline or
468 // multiple return sites.
470 // We want to clone the entire callee function into the hole between the
471 // "starter" and "ender" blocks. How we accomplish this depends on whether
472 // this is an invoke instruction or a call instruction.
473 BasicBlock *AfterCallBB;
474 if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall)) {
476 // Add an unconditional branch to make this look like the CallInst case...
477 BranchInst *NewBr = BranchInst::Create(II->getNormalDest(), TheCall);
479 // Split the basic block. This guarantees that no PHI nodes will have to be
480 // updated due to new incoming edges, and make the invoke case more
481 // symmetric to the call case.
482 AfterCallBB = OrigBB->splitBasicBlock(NewBr,
483 CalledFunc->getName()+".exit");
485 } else { // It's a call
486 // If this is a call instruction, we need to split the basic block that
487 // the call lives in.
489 AfterCallBB = OrigBB->splitBasicBlock(TheCall,
490 CalledFunc->getName()+".exit");
493 // Change the branch that used to go to AfterCallBB to branch to the first
494 // basic block of the inlined function.
496 TerminatorInst *Br = OrigBB->getTerminator();
497 assert(Br && Br->getOpcode() == Instruction::Br &&
498 "splitBasicBlock broken!");
499 Br->setOperand(0, FirstNewBlock);
502 // Now that the function is correct, make it a little bit nicer. In
503 // particular, move the basic blocks inserted from the end of the function
504 // into the space made by splitting the source basic block.
505 Caller->getBasicBlockList().splice(AfterCallBB, Caller->getBasicBlockList(),
506 FirstNewBlock, Caller->end());
508 // Handle all of the return instructions that we just cloned in, and eliminate
509 // any users of the original call/invoke instruction.
510 const Type *RTy = CalledFunc->getReturnType();
511 const StructType *STy = dyn_cast<StructType>(RTy);
512 if (Returns.size() > 1 || STy) {
513 // The PHI node should go at the front of the new basic block to merge all
514 // possible incoming values.
515 SmallVector<PHINode *, 4> PHIs;
516 if (!TheCall->use_empty()) {
518 unsigned NumRetVals = STy->getNumElements();
519 // Create new phi nodes such that phi node number in the PHIs vector
520 // match corresponding return value operand number.
521 Instruction *InsertPt = AfterCallBB->begin();
522 for (unsigned i = 0; i < NumRetVals; ++i) {
523 PHINode *PHI = PHINode::Create(STy->getElementType(i),
524 TheCall->getName() + "." + utostr(i),
528 // TheCall results are used by GetResult instructions.
529 while (!TheCall->use_empty()) {
530 GetResultInst *GR = cast<GetResultInst>(TheCall->use_back());
531 GR->replaceAllUsesWith(PHIs[GR->getIndex()]);
532 GR->eraseFromParent();
535 PHINode *PHI = PHINode::Create(RTy, TheCall->getName(),
536 AfterCallBB->begin());
538 // Anything that used the result of the function call should now use the
539 // PHI node as their operand.
540 TheCall->replaceAllUsesWith(PHI);
544 // Loop over all of the return instructions adding entries to the PHI node as
547 // There is atleast one return value.
548 unsigned NumRetVals = 1;
550 NumRetVals = STy->getNumElements();
551 for (unsigned j = 0; j < NumRetVals; ++j) {
552 PHINode *PHI = PHIs[j];
553 // Each PHI node will receive one value from each return instruction.
554 for(unsigned i = 0, e = Returns.size(); i != e; ++i) {
555 ReturnInst *RI = Returns[i];
556 assert(RI->getReturnValue(j)->getType() == PHI->getType() &&
557 "Ret value not consistent in function!");
558 PHI->addIncoming(RI->getReturnValue(j /*PHI number matches operand number*/),
564 // Add a branch to the merge points and remove retrun instructions.
565 for (unsigned i = 0, e = Returns.size(); i != e; ++i) {
566 ReturnInst *RI = Returns[i];
567 BranchInst::Create(AfterCallBB, RI);
568 RI->eraseFromParent();
570 } else if (!Returns.empty()) {
571 // Otherwise, if there is exactly one return value, just replace anything
572 // using the return value of the call with the computed value.
573 if (!TheCall->use_empty())
574 TheCall->replaceAllUsesWith(Returns[0]->getReturnValue());
576 // Splice the code from the return block into the block that it will return
577 // to, which contains the code that was after the call.
578 BasicBlock *ReturnBB = Returns[0]->getParent();
579 AfterCallBB->getInstList().splice(AfterCallBB->begin(),
580 ReturnBB->getInstList());
582 // Update PHI nodes that use the ReturnBB to use the AfterCallBB.
583 ReturnBB->replaceAllUsesWith(AfterCallBB);
585 // Delete the return instruction now and empty ReturnBB now.
586 Returns[0]->eraseFromParent();
587 ReturnBB->eraseFromParent();
588 } else if (!TheCall->use_empty()) {
589 // No returns, but something is using the return value of the call. Just
591 TheCall->replaceAllUsesWith(UndefValue::get(TheCall->getType()));
594 // Since we are now done with the Call/Invoke, we can delete it.
595 TheCall->eraseFromParent();
597 // We should always be able to fold the entry block of the function into the
598 // single predecessor of the block...
599 assert(cast<BranchInst>(Br)->isUnconditional() && "splitBasicBlock broken!");
600 BasicBlock *CalleeEntry = cast<BranchInst>(Br)->getSuccessor(0);
602 // Splice the code entry block into calling block, right before the
603 // unconditional branch.
604 OrigBB->getInstList().splice(Br, CalleeEntry->getInstList());
605 CalleeEntry->replaceAllUsesWith(OrigBB); // Update PHI nodes
607 // Remove the unconditional branch.
608 OrigBB->getInstList().erase(Br);
610 // Now we can remove the CalleeEntry block, which is now empty.
611 Caller->getBasicBlockList().erase(CalleeEntry);