C++ AllocaInst::getArraySize方法代码示例

bool CallAnalyzer::visitAlloca(AllocaInst &I) {
  // Check whether inlining will turn a dynamic alloca into a static
  // alloca, and handle that case.
  if (I.isArrayAllocation()) {
    if (Constant *Size = SimplifiedValues.lookup(I.getArraySize())) {
      ConstantInt *AllocSize = dyn_cast<ConstantInt>(Size);
      assert(AllocSize && "Allocation size not a constant int?");
      Type *Ty = I.getAllocatedType();
      AllocatedSize += Ty->getPrimitiveSizeInBits() * AllocSize->getZExtValue();
      return Base::visitAlloca(I);
    }
  }

  // Accumulate the allocated size.
  if (I.isStaticAlloca()) {
    Type *Ty = I.getAllocatedType();
    AllocatedSize += (DL ? DL->getTypeAllocSize(Ty) :
                      Ty->getPrimitiveSizeInBits());
  }

  // We will happily inline static alloca instructions.
  if (I.isStaticAlloca())
    return Base::visitAlloca(I);

  // FIXME: This is overly conservative. Dynamic allocas are inefficient for
  // a variety of reasons, and so we would like to not inline them into
  // functions which don't currently have a dynamic alloca. This simply
  // disables inlining altogether in the presence of a dynamic alloca.
  HasDynamicAlloca = true;
  return false;
}

void Lint::visitAllocaInst(AllocaInst &I) {
  if (isa<ConstantInt>(I.getArraySize()))
    // This isn't undefined behavior, it's just an obvious pessimization.
    Assert(&I.getParent()->getParent()->getEntryBlock() == I.getParent(),
           "Pessimization: Static alloca outside of entry block", &I);

  // TODO: Check for an unusual size (MSB set?)
}

SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitAllocaInst(AllocaInst &I) {
  if (!I.getAllocatedType()->isSized())
    return unknown();

  // must be a VLA
  assert(I.isArrayAllocation());
  Value *ArraySize = I.getArraySize();
  Value *Size = ConstantInt::get(ArraySize->getType(),
                                 TD->getTypeAllocSize(I.getAllocatedType()));
  Size = Builder.CreateMul(Size, ArraySize);
  return std::make_pair(Size, Zero);
}

bool NVPTXAllocaHoisting::runOnFunction(Function &function) {
  bool functionModified = false;
  Function::iterator I = function.begin();
  TerminatorInst *firstTerminatorInst = (I++)->getTerminator();

  for (Function::iterator E = function.end(); I != E; ++I) {
    for (BasicBlock::iterator BI = I->begin(), BE = I->end(); BI != BE;) {
      AllocaInst *allocaInst = dyn_cast<AllocaInst>(BI++);
      if (allocaInst && isa<ConstantInt>(allocaInst->getArraySize())) {
        allocaInst->moveBefore(firstTerminatorInst);
        functionModified = true;
      }
    }
  }

  return functionModified;
}

bool IRTranslator::translateStaticAlloca(const AllocaInst &AI) {
  assert(AI.isStaticAlloca() && "only handle static allocas now");
  MachineFunction &MF = MIRBuilder.getMF();
  unsigned ElementSize = DL->getTypeStoreSize(AI.getAllocatedType());
  unsigned Size =
      ElementSize * cast<ConstantInt>(AI.getArraySize())->getZExtValue();

  // Always allocate at least one byte.
  Size = std::max(Size, 1u);

  unsigned Alignment = AI.getAlignment();
  if (!Alignment)
    Alignment = DL->getABITypeAlignment(AI.getAllocatedType());

  unsigned Res = getOrCreateVReg(AI);
  int FI = MF.getFrameInfo().CreateStackObject(Size, Alignment, false, &AI);
  MIRBuilder.buildFrameIndex(LLT::pointer(0), Res, FI);
  return true;
}

int IRTranslator::getOrCreateFrameIndex(const AllocaInst &AI) {
  if (FrameIndices.find(&AI) != FrameIndices.end())
    return FrameIndices[&AI];

  MachineFunction &MF = MIRBuilder.getMF();
  unsigned ElementSize = DL->getTypeStoreSize(AI.getAllocatedType());
  unsigned Size =
      ElementSize * cast<ConstantInt>(AI.getArraySize())->getZExtValue();

  // Always allocate at least one byte.
  Size = std::max(Size, 1u);

  unsigned Alignment = AI.getAlignment();
  if (!Alignment)
    Alignment = DL->getABITypeAlignment(AI.getAllocatedType());

  int &FI = FrameIndices[&AI];
  FI = MF.getFrameInfo().CreateStackObject(Size, Alignment, false, &AI);
  return FI;
}

SizeOffsetType ObjectSizeOffsetVisitor::visitAllocaInst(AllocaInst &I) {
  if (!I.getAllocatedType()->isSized())
    return unknown();

  APInt Size(IntTyBits, DL.getTypeAllocSize(I.getAllocatedType()));
  if (!I.isArrayAllocation())
    return std::make_pair(align(Size, I.getAlignment()), Zero);

  Value *ArraySize = I.getArraySize();
  if (const ConstantInt *C = dyn_cast<ConstantInt>(ArraySize)) {
    APInt NumElems = C->getValue();
    if (!CheckedZextOrTrunc(NumElems))
      return unknown();

    bool Overflow;
    Size = Size.umul_ov(NumElems, Overflow);
    return Overflow ? unknown() : std::make_pair(align(Size, I.getAlignment()),
                                                 Zero);
  }
  return unknown();
}

/// performCallSlotOptzn - takes a memcpy and a call that it depends on,
/// and checks for the possibility of a call slot optimization by having
/// the call write its result directly into the destination of the memcpy.
bool MemCpyOpt::performCallSlotOptzn(Instruction *cpy,
                                     Value *cpyDest, Value *cpySrc,
                                     uint64_t cpyLen, unsigned cpyAlign,
                                     CallInst *C) {
    // The general transformation to keep in mind is
    //
    //   call @func(..., src, ...)
    //   memcpy(dest, src, ...)
    //
    // ->
    //
    //   memcpy(dest, src, ...)
    //   call @func(..., dest, ...)
    //
    // Since moving the memcpy is technically awkward, we additionally check that
    // src only holds uninitialized values at the moment of the call, meaning that
    // the memcpy can be discarded rather than moved.

    // Deliberately get the source and destination with bitcasts stripped away,
    // because we'll need to do type comparisons based on the underlying type.
    CallSite CS(C);

    // Require that src be an alloca.  This simplifies the reasoning considerably.
    AllocaInst *srcAlloca = dyn_cast<AllocaInst>(cpySrc);
    if (!srcAlloca)
        return false;

    // Check that all of src is copied to dest.
    if (TD == 0) return false;

    ConstantInt *srcArraySize = dyn_cast<ConstantInt>(srcAlloca->getArraySize());
    if (!srcArraySize)
        return false;

    uint64_t srcSize = TD->getTypeAllocSize(srcAlloca->getAllocatedType()) *
                       srcArraySize->getZExtValue();

    if (cpyLen < srcSize)
        return false;

    // Check that dest points to memory that is at least as aligned as src.
    unsigned srcAlign = srcAlloca->getAlignment();
    if (!srcAlign)
        srcAlign = TD->getABITypeAlignment(srcAlloca->getAllocatedType());
    bool isDestSufficientlyAligned = srcAlign <= cpyAlign;
    // If dest is not aligned enough and we can't increase its alignment then
    // bail out.
    if (!isDestSufficientlyAligned && !isa<AllocaInst>(cpyDest))
        return false;

    // Check that accessing the first srcSize bytes of dest will not cause a
    // trap.  Otherwise the transform is invalid since it might cause a trap
    // to occur earlier than it otherwise would.
    if (AllocaInst *A = dyn_cast<AllocaInst>(cpyDest)) {
        // The destination is an alloca.  Check it is larger than srcSize.
        ConstantInt *destArraySize = dyn_cast<ConstantInt>(A->getArraySize());
        if (!destArraySize)
            return false;

        uint64_t destSize = TD->getTypeAllocSize(A->getAllocatedType()) *
                            destArraySize->getZExtValue();

        if (destSize < srcSize)
            return false;
    } else if (Argument *A = dyn_cast<Argument>(cpyDest)) {
        // If the destination is an sret parameter then only accesses that are
        // outside of the returned struct type can trap.
        if (!A->hasStructRetAttr())
            return false;

        Type *StructTy = cast<PointerType>(A->getType())->getElementType();
        uint64_t destSize = TD->getTypeAllocSize(StructTy);

        if (destSize < srcSize)
            return false;
    } else {
        return false;
    }

    // Check that src is not accessed except via the call and the memcpy.  This
    // guarantees that it holds only undefined values when passed in (so the final
    // memcpy can be dropped), that it is not read or written between the call and
    // the memcpy, and that writing beyond the end of it is undefined.
    SmallVector<User*, 8> srcUseList(srcAlloca->use_begin(),
                                     srcAlloca->use_end());
    while (!srcUseList.empty()) {
        User *UI = srcUseList.pop_back_val();

        if (isa<BitCastInst>(UI)) {
            for (User::use_iterator I = UI->use_begin(), E = UI->use_end();
                    I != E; ++I)
                srcUseList.push_back(*I);
        } else if (GetElementPtrInst *G = dyn_cast<GetElementPtrInst>(UI)) {
            if (G->hasAllZeroIndices())
                for (User::use_iterator I = UI->use_begin(), E = UI->use_end();
                        I != E; ++I)
                    srcUseList.push_back(*I);
//.........这里部分代码省略.........

/// performCallSlotOptzn - takes a memcpy and a call that it depends on,
/// and checks for the possibility of a call slot optimization by having
/// the call write its result directly into the destination of the memcpy.
bool MemCpyOpt::performCallSlotOptzn(Instruction *cpy,
                                     Value *cpyDest, Value *cpySrc,
                                     uint64_t cpyLen, unsigned cpyAlign,
                                     CallInst *C) {
  // The general transformation to keep in mind is
  //
  //   call @func(..., src, ...)
  //   memcpy(dest, src, ...)
  //
  // ->
  //
  //   memcpy(dest, src, ...)
  //   call @func(..., dest, ...)
  //
  // Since moving the memcpy is technically awkward, we additionally check that
  // src only holds uninitialized values at the moment of the call, meaning that
  // the memcpy can be discarded rather than moved.

  // Deliberately get the source and destination with bitcasts stripped away,
  // because we'll need to do type comparisons based on the underlying type.
  CallSite CS(C);

  // Require that src be an alloca.  This simplifies the reasoning considerably.
  AllocaInst *srcAlloca = dyn_cast<AllocaInst>(cpySrc);
  if (!srcAlloca)
    return false;

  ConstantInt *srcArraySize = dyn_cast<ConstantInt>(srcAlloca->getArraySize());
  if (!srcArraySize)
    return false;

  const DataLayout &DL = cpy->getModule()->getDataLayout();
  uint64_t srcSize = DL.getTypeAllocSize(srcAlloca->getAllocatedType()) *
                     srcArraySize->getZExtValue();

  if (cpyLen < srcSize)
    return false;

  // Check that accessing the first srcSize bytes of dest will not cause a
  // trap.  Otherwise the transform is invalid since it might cause a trap
  // to occur earlier than it otherwise would.
  if (AllocaInst *A = dyn_cast<AllocaInst>(cpyDest)) {
    // The destination is an alloca.  Check it is larger than srcSize.
    ConstantInt *destArraySize = dyn_cast<ConstantInt>(A->getArraySize());
    if (!destArraySize)
      return false;

    uint64_t destSize = DL.getTypeAllocSize(A->getAllocatedType()) *
                        destArraySize->getZExtValue();

    if (destSize < srcSize)
      return false;
  } else if (Argument *A = dyn_cast<Argument>(cpyDest)) {
    if (A->getDereferenceableBytes() < srcSize) {
      // If the destination is an sret parameter then only accesses that are
      // outside of the returned struct type can trap.
      if (!A->hasStructRetAttr())
        return false;

      Type *StructTy = cast<PointerType>(A->getType())->getElementType();
      if (!StructTy->isSized()) {
        // The call may never return and hence the copy-instruction may never
        // be executed, and therefore it's not safe to say "the destination
        // has at least <cpyLen> bytes, as implied by the copy-instruction",
        return false;
      }

      uint64_t destSize = DL.getTypeAllocSize(StructTy);
      if (destSize < srcSize)
        return false;
    }
  } else {
    return false;
  }

  // Check that dest points to memory that is at least as aligned as src.
  unsigned srcAlign = srcAlloca->getAlignment();
  if (!srcAlign)
    srcAlign = DL.getABITypeAlignment(srcAlloca->getAllocatedType());
  bool isDestSufficientlyAligned = srcAlign <= cpyAlign;
  // If dest is not aligned enough and we can't increase its alignment then
  // bail out.
  if (!isDestSufficientlyAligned && !isa<AllocaInst>(cpyDest))
    return false;

  // Check that src is not accessed except via the call and the memcpy.  This
  // guarantees that it holds only undefined values when passed in (so the final
  // memcpy can be dropped), that it is not read or written between the call and
  // the memcpy, and that writing beyond the end of it is undefined.
  SmallVector<User*, 8> srcUseList(srcAlloca->user_begin(),
                                   srcAlloca->user_end());
  while (!srcUseList.empty()) {
    User *U = srcUseList.pop_back_val();

    if (isa<BitCastInst>(U) || isa<AddrSpaceCastInst>(U)) {
      for (User *UU : U->users())
        srcUseList.push_back(UU);
//.........这里部分代码省略.........

//.........这里部分代码省略.........
    CloneAndPruneFunctionInto(Caller, CalledFunc, VMap, 
                              /*ModuleLevelChanges=*/false, Returns, ".i",
                              &InlinedFunctionInfo, IFI.TD, TheCall);

    // Remember the first block that is newly cloned over.
    FirstNewBlock = LastBlock; ++FirstNewBlock;

    // Update the callgraph if requested.
    if (IFI.CG)
      UpdateCallGraphAfterInlining(CS, FirstNewBlock, VMap, IFI);

    // Update inlined instructions' line number information.
    fixupLineNumbers(Caller, FirstNewBlock, TheCall);
  }

  // If there are any alloca instructions in the block that used to be the entry
  // block for the callee, move them to the entry block of the caller.  First
  // calculate which instruction they should be inserted before.  We insert the
  // instructions at the end of the current alloca list.
  {
    BasicBlock::iterator InsertPoint = Caller->begin()->begin();
    for (BasicBlock::iterator I = FirstNewBlock->begin(),
         E = FirstNewBlock->end(); I != E; ) {
      AllocaInst *AI = dyn_cast<AllocaInst>(I++);
      if (AI == 0) continue;
      
      // If the alloca is now dead, remove it.  This often occurs due to code
      // specialization.
      if (AI->use_empty()) {
        AI->eraseFromParent();
        continue;
      }

      if (!isa<Constant>(AI->getArraySize()))
        continue;
      
      // Keep track of the static allocas that we inline into the caller.
      IFI.StaticAllocas.push_back(AI);
      
      // Scan for the block of allocas that we can move over, and move them
      // all at once.
      while (isa<AllocaInst>(I) &&
             isa<Constant>(cast<AllocaInst>(I)->getArraySize())) {
        IFI.StaticAllocas.push_back(cast<AllocaInst>(I));
        ++I;
      }

      // Transfer all of the allocas over in a block.  Using splice means
      // that the instructions aren't removed from the symbol table, then
      // reinserted.
      Caller->getEntryBlock().getInstList().splice(InsertPoint,
                                                   FirstNewBlock->getInstList(),
                                                   AI, I);
    }
  }

  // Leave lifetime markers for the static alloca's, scoping them to the
  // function we just inlined.
  if (InsertLifetime && !IFI.StaticAllocas.empty()) {
    IRBuilder<> builder(FirstNewBlock->begin());
    for (unsigned ai = 0, ae = IFI.StaticAllocas.size(); ai != ae; ++ai) {
      AllocaInst *AI = IFI.StaticAllocas[ai];

      // If the alloca is already scoped to something smaller than the whole
      // function then there's no need to add redundant, less accurate markers.
      if (hasLifetimeMarkers(AI))

/*
 * Rewrite OpenMP call sites and their associated kernel functions  -- the folloiwng pattern
   call void @GOMP_parallel_start(void (i8*)* @_Z20initialize_variablesiPfS_.omp_fn.4, i8* %.omp_data_o.5571, i32 0) nounwind
  call void @_Z20initialize_variablesiPfS_.omp_fn.4(i8* %.omp_data_o.5571) nounwind
  call void @GOMP_parallel_end() nounwind
 */
void HeteroOMPTransform::rewrite_omp_call_sites(Module &M) {
	SmallVector<Instruction *, 16> toDelete;
	DenseMap<Value *, Value *> ValueMap;
	
	for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I){
		if (!I->isDeclaration()) {
			
			for (Function::iterator BBI = I->begin(), BBE = I->end(); BBI != BBE; ++BBI) {
				bool match = false;
				for (BasicBlock::iterator INSNI = BBI->begin(), INSNE = BBI->end(); INSNI != INSNE; ++INSNI) {
					if (isa<CallInst>(INSNI)) {
						CallSite CI(cast<Instruction>(INSNI));
						if (CI.getCalledFunction() != NULL){ 
							string called_func_name = CI.getCalledFunction()->getName();
							if (called_func_name == OMP_PARALLEL_START_NAME && CI.arg_size() == 3) {
								// change alloc to malloc_shared
								// %5 = call i8* @_Z13malloc_sharedm(i64 20)       ; <i8*> [#uses=5]
								// %6 = bitcast i8* %5 to float*                   ; <float*> [#uses=2]
								AllocaInst *AllocCall;
								Value *arg_0 = CI.getArgument(0); // function
								Value *arg_1 = CI.getArgument(1);  // context
								Value *loop_ub = NULL;
								Function *function;
								BitCastInst* BCI;
								Function *kernel_function;
								BasicBlock::iterator iI(*INSNI); 
								//BasicBlock::iterator iJ = iI+1; 
								iI++; iI++;
								//BasicBlock::iterator iK = iI;  
								CallInst /**next,*/ *next_next; 
								if (arg_0 != NULL && arg_1 != NULL /*&& (next = dyn_cast<CallInst>(*iJ))*/ 
									&& (next_next = dyn_cast<CallInst>(iI)) && (next_next->getCalledFunction() != NULL) 
									&& (next_next->getCalledFunction()->getName() == OMP_PARALLEL_END_NAME)
									&& (BCI = dyn_cast<BitCastInst>(arg_1)) && (AllocCall = dyn_cast<AllocaInst>(BCI->getOperand(0))) 
									&& (function = dyn_cast<Function>(arg_0)) && (loop_ub = find_loop_upper_bound (AllocCall)) 
									&& (kernel_function=convert_to_kernel_function (M, function))){
									
										SmallVector<Value*, 16> Args;
										Args.push_back(AllocCall->getArraySize());
										Instruction *MallocCall = CallInst::Create(mallocFnTy, Args, "", AllocCall);
										CastInst *MallocCast = CastInst::Create(Instruction::BitCast, MallocCall, AllocCall->getType(), "", AllocCall);
										ValueMap[AllocCall] = MallocCast;
										//AllocCall->replaceAllUsesWith(MallocCall);
										// Add offload function
										Args.clear();
										Args.push_back(loop_ub);
										Args.push_back(BCI);
										Args.push_back(kernel_function);
										if (offloadFnTy == NULL) {
											init_offload_type(M, kernel_function);
										}
										
										Instruction *call = CallInst::Create(offloadFnTy, Args, "", INSNI);
										
										if (find(toDelete.begin(), toDelete.end(), AllocCall) == toDelete.end()){
											toDelete.push_back(AllocCall);
										}
										toDelete.push_back(&(*INSNI));
										match = true;
								}
							}
							else if (called_func_name == OMP_PARALLEL_END_NAME && CI.arg_size() == 0 && match) {
								toDelete.push_back(&(*INSNI));
								match = false;
							}
							else if (match) {
								toDelete.push_back(&(*INSNI));
							}
						}
					}
				}
			}
		}

	}

	/* Replace AllocCalls by MallocCalls */
	for(DenseMap<Value *, Value *>::iterator I = ValueMap.begin(), E = ValueMap.end(); I != E; I++) {
		I->first->replaceAllUsesWith(I->second);
	}

	/* delete the instructions for get_omp_num_thread and get_omp_thread_num */
	while(!toDelete.empty()) {
		Instruction *g = toDelete.back();
		toDelete.pop_back();
		g->eraseFromParent();
	}

}

//
// Method: insertBadAllocationSizes()
//
// Description:
//  This method will look for allocations and change their size to be
//  incorrect.  It does the following:
//    o) Changes the number of array elements allocated by alloca and malloc.
//
// Return value:
//  true  - The module was modified.
//  false - The module was left unmodified.
//
bool
FaultInjector::insertBadAllocationSizes  (Function & F) {
  // Worklist of allocation sites to rewrite
  std::vector<AllocaInst * > WorkList;

  for (Function::iterator fI = F.begin(), fE = F.end(); fI != fE; ++fI) {
    BasicBlock & BB = *fI;
    for (BasicBlock::iterator I = BB.begin(), bE = BB.end(); I != bE; ++I) {
      if (AllocaInst * AI = dyn_cast<AllocaInst>(I)) {
        if (AI->isArrayAllocation()) {
          // Skip if we should not insert a fault.
          if (!doFault()) continue;

          WorkList.push_back(AI);
        }
      }
    }
  }

  while (WorkList.size()) {
    AllocaInst * AI = WorkList.back();
    WorkList.pop_back();

    //
    // Print information about where the fault is being inserted.
    //
    printSourceInfo ("Bad allocation size", AI);

    Instruction * NewAlloc = 0;
    NewAlloc =  new AllocaInst (AI->getAllocatedType(),
                                ConstantInt::get(Int32Type,0),
                                AI->getAlignment(),
                                AI->getName(),
                                AI);
    AI->replaceAllUsesWith (NewAlloc);
    AI->eraseFromParent();
    ++BadSizes;
  }

  //
  // Try harder to make bad allocation sizes.
  //
  WorkList.clear();
  for (Function::iterator fI = F.begin(), fE = F.end(); fI != fE; ++fI) {
    BasicBlock & BB = *fI;
    for (BasicBlock::iterator I = BB.begin(), bE = BB.end(); I != bE; ++I) {
      if (AllocaInst * AI = dyn_cast<AllocaInst>(I)) {
        //
        // Determine if this is a data type that we can make smaller.
        //
        if (((TD->getTypeAllocSize(AI->getAllocatedType())) > 4) && doFault()) {
          WorkList.push_back(AI);
        }
      }
    }
  }

  //
  // Replace these allocations with an allocation of an integer and cast the
  // result back into the appropriate type.
  //
  while (WorkList.size()) {
    AllocaInst * AI = WorkList.back();
    WorkList.pop_back();

    Instruction * NewAlloc = 0;
    NewAlloc =  new AllocaInst (Int32Type,
                                AI->getArraySize(),
                                AI->getAlignment(),
                                AI->getName(),
                                AI);
    NewAlloc = castTo (NewAlloc, AI->getType(), "", AI);
    AI->replaceAllUsesWith (NewAlloc);
    AI->eraseFromParent();
    ++BadSizes;
  }

  return (BadSizes > 0);
}

//.........这里部分代码省略.........
    // have no dead or constant instructions leftover after inlining occurs
    // (which can happen, e.g., because an argument was constant), but we'll be
    // happy with whatever the cloner can do.
    CloneAndPruneFunctionInto(Caller, CalledFunc, VMap, Returns, ".i",
                              &InlinedFunctionInfo, IFI.TD, TheCall);

    // Remember the first block that is newly cloned over.
    FirstNewBlock = LastBlock; ++FirstNewBlock;

    // Update the callgraph if requested.
    if (IFI.CG)
      UpdateCallGraphAfterInlining(CS, FirstNewBlock, VMap, IFI);
  }

  // If there are any alloca instructions in the block that used to be the entry
  // block for the callee, move them to the entry block of the caller.  First
  // calculate which instruction they should be inserted before.  We insert the
  // instructions at the end of the current alloca list.
  //
  {
    BasicBlock::iterator InsertPoint = Caller->begin()->begin();
    for (BasicBlock::iterator I = FirstNewBlock->begin(),
         E = FirstNewBlock->end(); I != E; ) {
      AllocaInst *AI = dyn_cast<AllocaInst>(I++);
      if (AI == 0) continue;
      
      // If the alloca is now dead, remove it.  This often occurs due to code
      // specialization.
      if (AI->use_empty()) {
        AI->eraseFromParent();
        continue;
      }

      if (!isa<Constant>(AI->getArraySize()))
        continue;
      
      // Keep track of the static allocas that we inline into the caller if the
      // StaticAllocas pointer is non-null.
      IFI.StaticAllocas.push_back(AI);
      
      // Scan for the block of allocas that we can move over, and move them
      // all at once.
      while (isa<AllocaInst>(I) &&
             isa<Constant>(cast<AllocaInst>(I)->getArraySize())) {
        IFI.StaticAllocas.push_back(cast<AllocaInst>(I));
        ++I;
      }

      // Transfer all of the allocas over in a block.  Using splice means
      // that the instructions aren't removed from the symbol table, then
      // reinserted.
      Caller->getEntryBlock().getInstList().splice(InsertPoint,
                                                   FirstNewBlock->getInstList(),
                                                   AI, I);
    }
  }

  // If the inlined code contained dynamic alloca instructions, wrap the inlined
  // code with llvm.stacksave/llvm.stackrestore intrinsics.
  if (InlinedFunctionInfo.ContainsDynamicAllocas) {
    Module *M = Caller->getParent();
    // Get the two intrinsics we care about.
    Function *StackSave = Intrinsic::getDeclaration(M, Intrinsic::stacksave);
    Function *StackRestore=Intrinsic::getDeclaration(M,Intrinsic::stackrestore);

    // If we are preserving the callgraph, add edges to the stacksave/restore