1 //===- llvm/Transforms/Utils/LoopUtils.h - Loop utilities -*- 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 // This file defines some loop transformation utilities. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #ifndef LLVM_TRANSFORMS_UTILS_LOOPUTILS_H 15 #define LLVM_TRANSFORMS_UTILS_LOOPUTILS_H 16 17 namespace llvm { 18 class AliasAnalysis; 19 class BasicBlock; 20 class DataLayout; 21 class DominatorTree; 22 class Loop; 23 class LoopInfo; 24 class Pass; 25 class ScalarEvolution; 26 27 BasicBlock *InsertPreheaderForLoop(Loop *L, Pass *P); 28 29 /// \brief Simplify each loop in a loop nest recursively. 30 /// 31 /// This takes a potentially un-simplified loop L (and its children) and turns 32 /// it into a simplified loop nest with preheaders and single backedges. It 33 /// will optionally update \c AliasAnalysis and \c ScalarEvolution analyses if 34 /// passed into it. 35 bool simplifyLoop(Loop *L, DominatorTree *DT, LoopInfo *LI, Pass *PP, 36 AliasAnalysis *AA = nullptr, ScalarEvolution *SE = nullptr, 37 const DataLayout *DL = nullptr); 38 39 /// \brief Put loop into LCSSA form. 40 /// 41 /// Looks at all instructions in the loop which have uses outside of the 42 /// current loop. For each, an LCSSA PHI node is inserted and the uses outside 43 /// the loop are rewritten to use this node. 44 /// 45 /// LoopInfo and DominatorTree are required and preserved. 46 /// 47 /// If ScalarEvolution is passed in, it will be preserved. 48 /// 49 /// Returns true if any modifications are made to the loop. 50 bool formLCSSA(Loop &L, DominatorTree &DT, ScalarEvolution *SE = nullptr); 51 52 /// \brief Put a loop nest into LCSSA form. 53 /// 54 /// This recursively forms LCSSA for a loop nest. 55 /// 56 /// LoopInfo and DominatorTree are required and preserved. 57 /// 58 /// If ScalarEvolution is passed in, it will be preserved. 59 /// 60 /// Returns true if any modifications are made to the loop. 61 bool formLCSSARecursively(Loop &L, DominatorTree &DT, 62 ScalarEvolution *SE = nullptr); 63 } 64 65 #endif 66