1//===-- AllocaHoisting.cpp - Hoist allocas to the entry block --*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// Hoist the alloca instructions in the non-entry blocks to the entry blocks.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/Function.h"
15#include "llvm/Instructions.h"
16#include "llvm/Constants.h"
17#include "NVPTXAllocaHoisting.h"
18
19namespace llvm {
20
21bool NVPTXAllocaHoisting::runOnFunction(Function &function) {
22  bool               functionModified    = false;
23  Function::iterator I                   = function.begin();
24  TerminatorInst    *firstTerminatorInst = (I++)->getTerminator();
25
26  for (Function::iterator E = function.end(); I != E; ++I) {
27    for (BasicBlock::iterator BI = I->begin(), BE = I->end(); BI != BE;) {
28      AllocaInst *allocaInst = dyn_cast<AllocaInst>(BI++);
29      if (allocaInst && isa<ConstantInt>(allocaInst->getArraySize())) {
30        allocaInst->moveBefore(firstTerminatorInst);
31        functionModified = true;
32      }
33    }
34  }
35
36  return functionModified;
37}
38
39char NVPTXAllocaHoisting::ID = 1;
40RegisterPass<NVPTXAllocaHoisting> X("alloca-hoisting",
41                                    "Hoisting alloca instructions in non-entry "
42                                    "blocks to the entry block");
43
44FunctionPass *createAllocaHoisting() {
45  return new NVPTXAllocaHoisting();
46}
47
48} // end namespace llvm
49