67 lines · cpp
1//===-- AllocaHoisting.cpp - Hoist allocas to the entry block --*- C++ -*-===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8//9// Hoist the alloca instructions in the non-entry blocks to the entry blocks.10//11//===----------------------------------------------------------------------===//12 13#include "NVPTXAllocaHoisting.h"14#include "NVPTX.h"15#include "llvm/CodeGen/StackProtector.h"16#include "llvm/IR/Constants.h"17#include "llvm/IR/Function.h"18#include "llvm/IR/Instructions.h"19using namespace llvm;20 21namespace {22// Hoisting the alloca instructions in the non-entry blocks to the entry23// block.24class NVPTXAllocaHoisting : public FunctionPass {25public:26 static char ID; // Pass ID27 NVPTXAllocaHoisting() : FunctionPass(ID) {}28 29 void getAnalysisUsage(AnalysisUsage &AU) const override {30 AU.addPreserved<StackProtector>();31 }32 33 StringRef getPassName() const override {34 return "NVPTX specific alloca hoisting";35 }36 37 bool runOnFunction(Function &function) override;38};39} // namespace40 41bool NVPTXAllocaHoisting::runOnFunction(Function &function) {42 bool functionModified = false;43 Function::iterator I = function.begin();44 Instruction *firstTerminatorInst = (I++)->getTerminator();45 46 for (Function::iterator E = function.end(); I != E; ++I) {47 for (BasicBlock::iterator BI = I->begin(), BE = I->end(); BI != BE;) {48 AllocaInst *allocaInst = dyn_cast<AllocaInst>(BI++);49 if (allocaInst && isa<ConstantInt>(allocaInst->getArraySize())) {50 allocaInst->moveBefore(firstTerminatorInst->getIterator());51 functionModified = true;52 }53 }54 }55 56 return functionModified;57}58 59char NVPTXAllocaHoisting::ID = 0;60 61INITIALIZE_PASS(62 NVPTXAllocaHoisting, "alloca-hoisting",63 "Hoisting alloca instructions in non-entry blocks to the entry block",64 false, false)65 66FunctionPass *llvm::createAllocaHoisting() { return new NVPTXAllocaHoisting; }67