1 //===- LoopInfo.cpp - Natural Loop Calculator -----------------------------===//
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 defines the LoopInfo class that is used to identify natural loops
11 // and determine the loop depth of various nodes of the CFG. Note that the
12 // loops identified may actually be several natural loops that share the same
13 // header node... not just a single natural loop.
15 //===----------------------------------------------------------------------===//
17 #include "llvm/Analysis/LoopInfo.h"
18 #include "llvm/Constants.h"
19 #include "llvm/Instructions.h"
20 #include "llvm/Analysis/Dominators.h"
21 #include "llvm/Assembly/Writer.h"
22 #include "llvm/Support/CFG.h"
23 #include "llvm/Support/Streams.h"
24 #include "llvm/ADT/DepthFirstIterator.h"
25 #include "llvm/ADT/SmallPtrSet.h"
30 char LoopInfo::ID = 0;
31 static RegisterPass<LoopInfo>
32 X("loops", "Natural Loop Construction", true, true);
34 //===----------------------------------------------------------------------===//
35 // Loop implementation
38 //===----------------------------------------------------------------------===//
39 // LoopInfo implementation
41 bool LoopInfo::runOnFunction(Function &) {
43 LI->Calculate(getAnalysis<DominatorTree>().getBase()); // Update
47 void LoopInfo::getAnalysisUsage(AnalysisUsage &AU) const {
49 AU.addRequired<DominatorTree>();