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 AssumptionCache; 20 class BasicBlock; 21 class DataLayout; 22 class DominatorTree; 23 class Loop; 24 class LoopInfo; 25 class Pass; 26 class ScalarEvolution; 27 28 BasicBlock *InsertPreheaderForLoop(Loop *L, Pass *P); 29 30 /// \brief Simplify each loop in a loop nest recursively. 31 /// 32 /// This takes a potentially un-simplified loop L (and its children) and turns 33 /// it into a simplified loop nest with preheaders and single backedges. It 34 /// will optionally update \c AliasAnalysis and \c ScalarEvolution analyses if 35 /// passed into it. 36 bool simplifyLoop(Loop *L, DominatorTree *DT, LoopInfo *LI, Pass *PP, 37 AliasAnalysis *AA = nullptr, ScalarEvolution *SE = nullptr, 38 const DataLayout *DL = nullptr, 39 AssumptionCache *AC = nullptr); 40 41 /// \brief Put loop into LCSSA form. 42 /// 43 /// Looks at all instructions in the loop which have uses outside of the 44 /// current loop. For each, an LCSSA PHI node is inserted and the uses outside 45 /// the loop are rewritten to use this node. 46 /// 47 /// LoopInfo and DominatorTree are required and preserved. 48 /// 49 /// If ScalarEvolution is passed in, it will be preserved. 50 /// 51 /// Returns true if any modifications are made to the loop. 52 bool formLCSSA(Loop &L, DominatorTree &DT, LoopInfo *LI, 53 ScalarEvolution *SE = nullptr); 54 55 /// \brief Put a loop nest into LCSSA form. 56 /// 57 /// This recursively forms LCSSA for a loop nest. 58 /// 59 /// LoopInfo and DominatorTree are required and preserved. 60 /// 61 /// If ScalarEvolution is passed in, it will be preserved. 62 /// 63 /// Returns true if any modifications are made to the loop. 64 bool formLCSSARecursively(Loop &L, DominatorTree &DT, LoopInfo *LI, 65 ScalarEvolution *SE = nullptr); 66 } 67 68 #endif 69