LICM.cpp revision aab8e28d5e470711d80276bbf717408c3ab966fd
1e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner//===-- LICM.cpp - Loop Invariant Code Motion Pass ------------------------===// 2fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman// 3b576c94c15af9a440f69d9d03c2afead7971118cJohn Criswell// The LLVM Compiler Infrastructure 4b576c94c15af9a440f69d9d03c2afead7971118cJohn Criswell// 54ee451de366474b9c228b4e5fa573795a715216dChris Lattner// This file is distributed under the University of Illinois Open Source 64ee451de366474b9c228b4e5fa573795a715216dChris Lattner// License. See LICENSE.TXT for details. 7fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman// 8b576c94c15af9a440f69d9d03c2afead7971118cJohn Criswell//===----------------------------------------------------------------------===// 9e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner// 1092094b4d928119eceac1484331acffe950f4651cChris Lattner// This pass performs loop invariant code motion, attempting to remove as much 1192094b4d928119eceac1484331acffe950f4651cChris Lattner// code from the body of a loop as possible. It does this by either hoisting 1292094b4d928119eceac1484331acffe950f4651cChris Lattner// code into the preheader block, or by sinking code to the exit blocks if it is 1392094b4d928119eceac1484331acffe950f4651cChris Lattner// safe. This pass also promotes must-aliased memory locations in the loop to 14e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner// live in registers, thus hoisting and sinking "invariant" loads and stores. 1592094b4d928119eceac1484331acffe950f4651cChris Lattner// 1692094b4d928119eceac1484331acffe950f4651cChris Lattner// This pass uses alias analysis for two purposes: 172e6e741b737960ecd0b68610875050019aac0f07Chris Lattner// 182741c971044d2165be572749b94398043caccfebChris Lattner// 1. Moving loop invariant loads and calls out of loops. If we can determine 192741c971044d2165be572749b94398043caccfebChris Lattner// that a load or call inside of a loop never aliases anything stored to, 202741c971044d2165be572749b94398043caccfebChris Lattner// we can hoist it or sink it like any other instruction. 212e6e741b737960ecd0b68610875050019aac0f07Chris Lattner// 2. Scalar Promotion of Memory - If there is a store instruction inside of 222e6e741b737960ecd0b68610875050019aac0f07Chris Lattner// the loop, we try to move the store to happen AFTER the loop instead of 232e6e741b737960ecd0b68610875050019aac0f07Chris Lattner// inside of the loop. This can only happen if a few conditions are true: 242e6e741b737960ecd0b68610875050019aac0f07Chris Lattner// A. The pointer stored through is loop invariant 252e6e741b737960ecd0b68610875050019aac0f07Chris Lattner// B. There are no stores or loads in the loop which _may_ alias the 262e6e741b737960ecd0b68610875050019aac0f07Chris Lattner// pointer. There are no calls in the loop which mod/ref the pointer. 272e6e741b737960ecd0b68610875050019aac0f07Chris Lattner// If these conditions are true, we can promote the loads and stores in the 282e6e741b737960ecd0b68610875050019aac0f07Chris Lattner// loop of the pointer to use a temporary alloca'd variable. We then use 29e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner// the SSAUpdater to construct the appropriate SSA form for the value. 30e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner// 31e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner//===----------------------------------------------------------------------===// 32e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner 331f309c1a4e8068a64627c612a895d9b403dbcb26Chris Lattner#define DEBUG_TYPE "licm" 34e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner#include "llvm/Transforms/Scalar.h" 3579066fa6acce02c97c714a5a6e151ed8a249721cChris Lattner#include "llvm/Constants.h" 362741c971044d2165be572749b94398043caccfebChris Lattner#include "llvm/DerivedTypes.h" 379289ae85b41eef62ae1fadb93e99d33f723fb682Torok Edwin#include "llvm/IntrinsicInst.h" 382741c971044d2165be572749b94398043caccfebChris Lattner#include "llvm/Instructions.h" 39a8702eaf78e70e1eef8a63882ce97ae6d60edf5bDan Gohman#include "llvm/LLVMContext.h" 40f5e84aa0887d3fcd752d4a4fa1bb0e526be49f20Chris Lattner#include "llvm/Analysis/AliasAnalysis.h" 410252e49f6d6973b6f347c8feafc49e28af27163aChris Lattner#include "llvm/Analysis/AliasSetTracker.h" 422ac6e2354ac9961b00fa351635ed04baf7fdd234Chris Lattner#include "llvm/Analysis/ConstantFolding.h" 432ac6e2354ac9961b00fa351635ed04baf7fdd234Chris Lattner#include "llvm/Analysis/LoopInfo.h" 442ac6e2354ac9961b00fa351635ed04baf7fdd234Chris Lattner#include "llvm/Analysis/LoopPass.h" 45952eaee239d6c38f5121ed68277555344c2d6bf0Chris Lattner#include "llvm/Analysis/Dominators.h" 460de5cad74d8d2987b92b8d76af3f1eab988b3c7bChris Lattner#include "llvm/Transforms/Utils/Local.h" 47a6a36f59b42703c5da0f68e0db37605c2e1633bfChris Lattner#include "llvm/Transforms/Utils/SSAUpdater.h" 48aab8e28d5e470711d80276bbf717408c3ab966fdChad Rosier#include "llvm/Target/TargetData.h" 49aab8e28d5e470711d80276bbf717408c3ab966fdChad Rosier#include "llvm/Target/TargetLibraryInfo.h" 509133fe28954d498fc4de13064c7d65bd811de02cReid Spencer#include "llvm/Support/CFG.h" 51551ccae044b0ff658fe629dd67edd5ffe75d10e8Reid Spencer#include "llvm/Support/CommandLine.h" 52ce63ffb52f249b62cdf2d250c128007b13f27e71Daniel Dunbar#include "llvm/Support/raw_ostream.h" 53551ccae044b0ff658fe629dd67edd5ffe75d10e8Reid Spencer#include "llvm/Support/Debug.h" 54551ccae044b0ff658fe629dd67edd5ffe75d10e8Reid Spencer#include "llvm/ADT/Statistic.h" 55e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner#include <algorithm> 5692094b4d928119eceac1484331acffe950f4651cChris Lattnerusing namespace llvm; 57d0fde30ce850b78371fd1386338350591f9ff494Brian Gaeke 580e5f499638c8d277b9dc4a4385712177c53b5681Chris LattnerSTATISTIC(NumSunk , "Number of instructions sunk out of loop"); 590e5f499638c8d277b9dc4a4385712177c53b5681Chris LattnerSTATISTIC(NumHoisted , "Number of instructions hoisted out of loop"); 600e5f499638c8d277b9dc4a4385712177c53b5681Chris LattnerSTATISTIC(NumMovedLoads, "Number of load insts hoisted or sunk"); 610e5f499638c8d277b9dc4a4385712177c53b5681Chris LattnerSTATISTIC(NumMovedCalls, "Number of call insts hoisted or sunk"); 620e5f499638c8d277b9dc4a4385712177c53b5681Chris LattnerSTATISTIC(NumPromoted , "Number of memory locations promoted to registers"); 630e5f499638c8d277b9dc4a4385712177c53b5681Chris Lattner 64844731a7f1909f55935e3514c9e713a62d67662eDan Gohmanstatic cl::opt<bool> 65844731a7f1909f55935e3514c9e713a62d67662eDan GohmanDisablePromotion("disable-licm-promotion", cl::Hidden, 66844731a7f1909f55935e3514c9e713a62d67662eDan Gohman cl::desc("Disable memory promotion in LICM pass")); 672e6e741b737960ecd0b68610875050019aac0f07Chris Lattner 68844731a7f1909f55935e3514c9e713a62d67662eDan Gohmannamespace { 693e8b6631e67e01e4960a7ba4668a50c596607473Chris Lattner struct LICM : public LoopPass { 70ecd94c804a563f2a86572dcf1d2e81f397e19daaNick Lewycky static char ID; // Pass identification, replacement for typeid 71081c34b725980f995be9080eaec24cd3dfaaf065Owen Anderson LICM() : LoopPass(ID) { 72081c34b725980f995be9080eaec24cd3dfaaf065Owen Anderson initializeLICMPass(*PassRegistry::getPassRegistry()); 73081c34b725980f995be9080eaec24cd3dfaaf065Owen Anderson } 74794fd75c67a2cdc128d67342c6d88a504d186896Devang Patel 7554959d6cf68a9b575c98c074babe9867682a7271Devang Patel virtual bool runOnLoop(Loop *L, LPPassManager &LPM); 76e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner 7794170596b715928794a55bc5a1671e3992fd2dc9Chris Lattner /// This transformation requires natural loop information & requires that 7894170596b715928794a55bc5a1671e3992fd2dc9Chris Lattner /// loop preheaders be inserted into the CFG... 7994170596b715928794a55bc5a1671e3992fd2dc9Chris Lattner /// 80e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner virtual void getAnalysisUsage(AnalysisUsage &AU) const { 81cb2610ea037a17115ef3a01a6bdaab4e3cfdca27Chris Lattner AU.setPreservesCFG(); 823a2b58f3adc5e9f9bffac7ce193f0570aa5a721fOwen Anderson AU.addRequired<DominatorTree>(); 831e381fcd553a3955a10338fd305efc023d7d22e1Dan Gohman AU.addRequired<LoopInfo>(); 841e381fcd553a3955a10338fd305efc023d7d22e1Dan Gohman AU.addRequiredID(LoopSimplifyID); 85f5e84aa0887d3fcd752d4a4fa1bb0e526be49f20Chris Lattner AU.addRequired<AliasAnalysis>(); 86e418ac832c1a2813736c44f6ec5c646b4c89c339Chris Lattner AU.addPreserved<AliasAnalysis>(); 87a9b61e7f7b1ab3a7344bbdc31c3e254c189fafccDan Gohman AU.addPreserved("scalar-evolution"); 885c89b5240c90eb8171f999e5f06f815502d0321cDan Gohman AU.addPreservedID(LoopSimplifyID); 89aab8e28d5e470711d80276bbf717408c3ab966fdChad Rosier AU.addRequired<TargetLibraryInfo>(); 90e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner } 91e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner 92747603e39ea3f29add9ba6c07bbefcc5c2432612Dan Gohman bool doFinalization() { 934282e32712da220fd97177772e22ec1ee7e50af2Chris Lattner assert(LoopToAliasSetMap.empty() && "Didn't free loop alias sets"); 9454959d6cf68a9b575c98c074babe9867682a7271Devang Patel return false; 9554959d6cf68a9b575c98c074babe9867682a7271Devang Patel } 9654959d6cf68a9b575c98c074babe9867682a7271Devang Patel 97e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner private: 982e6e741b737960ecd0b68610875050019aac0f07Chris Lattner AliasAnalysis *AA; // Current AliasAnalysis information 9992094b4d928119eceac1484331acffe950f4651cChris Lattner LoopInfo *LI; // Current LoopInfo 10044e2bd31f13da68bca451e4210560db3644b8208Chris Lattner DominatorTree *DT; // Dominator Tree for the current Loop. 10192094b4d928119eceac1484331acffe950f4651cChris Lattner 102aab8e28d5e470711d80276bbf717408c3ab966fdChad Rosier TargetData *TD; // TargetData for constant folding. 103aab8e28d5e470711d80276bbf717408c3ab966fdChad Rosier TargetLibraryInfo *TLI; // TargetLibraryInfo for constant folding. 104aab8e28d5e470711d80276bbf717408c3ab966fdChad Rosier 1054282e32712da220fd97177772e22ec1ee7e50af2Chris Lattner // State that is updated as we process loops. 1062e6e741b737960ecd0b68610875050019aac0f07Chris Lattner bool Changed; // Set to true when we change anything. 1072e6e741b737960ecd0b68610875050019aac0f07Chris Lattner BasicBlock *Preheader; // The preheader block of the current loop... 1082e6e741b737960ecd0b68610875050019aac0f07Chris Lattner Loop *CurLoop; // The current loop we are working on... 1090252e49f6d6973b6f347c8feafc49e28af27163aChris Lattner AliasSetTracker *CurAST; // AliasSet information for the current loop... 1104282e32712da220fd97177772e22ec1ee7e50af2Chris Lattner DenseMap<Loop*, AliasSetTracker*> LoopToAliasSetMap; 111e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner 11291d22c8b1ec2ad8f2f29804b729473ccf720fb3eDevang Patel /// cloneBasicBlockAnalysis - Simple Analysis hook. Clone alias set info. 11391d22c8b1ec2ad8f2f29804b729473ccf720fb3eDevang Patel void cloneBasicBlockAnalysis(BasicBlock *From, BasicBlock *To, Loop *L); 11491d22c8b1ec2ad8f2f29804b729473ccf720fb3eDevang Patel 11591d22c8b1ec2ad8f2f29804b729473ccf720fb3eDevang Patel /// deleteAnalysisValue - Simple Analysis hook. Delete value V from alias 11691d22c8b1ec2ad8f2f29804b729473ccf720fb3eDevang Patel /// set. 11791d22c8b1ec2ad8f2f29804b729473ccf720fb3eDevang Patel void deleteAnalysisValue(Value *V, Loop *L); 11891d22c8b1ec2ad8f2f29804b729473ccf720fb3eDevang Patel 119e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner /// SinkRegion - Walk the specified region of the CFG (defined by all blocks 120e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner /// dominated by the specified block, and that are in the current loop) in 1213a2b58f3adc5e9f9bffac7ce193f0570aa5a721fOwen Anderson /// reverse depth first order w.r.t the DominatorTree. This allows us to 122e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner /// visit uses before definitions, allowing us to sink a loop body in one 123e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner /// pass without iteration. 124e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner /// 12526042420d642e810f5cdfb2da6156b74aaf80945Devang Patel void SinkRegion(DomTreeNode *N); 126e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner 127952eaee239d6c38f5121ed68277555344c2d6bf0Chris Lattner /// HoistRegion - Walk the specified region of the CFG (defined by all 128952eaee239d6c38f5121ed68277555344c2d6bf0Chris Lattner /// blocks dominated by the specified block, and that are in the current 1293a2b58f3adc5e9f9bffac7ce193f0570aa5a721fOwen Anderson /// loop) in depth first order w.r.t the DominatorTree. This allows us to 130cf00c4ab3ba308d45d98c5ccab87362cf802facbMisha Brukman /// visit definitions before uses, allowing us to hoist a loop body in one 131952eaee239d6c38f5121ed68277555344c2d6bf0Chris Lattner /// pass without iteration. 132952eaee239d6c38f5121ed68277555344c2d6bf0Chris Lattner /// 13326042420d642e810f5cdfb2da6156b74aaf80945Devang Patel void HoistRegion(DomTreeNode *N); 134952eaee239d6c38f5121ed68277555344c2d6bf0Chris Lattner 135b461373fbcdc5909cc7331fa64791cd039de4bc8Chris Lattner /// inSubLoop - Little predicate that returns true if the specified basic 136b461373fbcdc5909cc7331fa64791cd039de4bc8Chris Lattner /// block is in a subloop of the current one, not the current one itself. 13794170596b715928794a55bc5a1671e3992fd2dc9Chris Lattner /// 138b461373fbcdc5909cc7331fa64791cd039de4bc8Chris Lattner bool inSubLoop(BasicBlock *BB) { 139b461373fbcdc5909cc7331fa64791cd039de4bc8Chris Lattner assert(CurLoop->contains(BB) && "Only valid if BB is IN the loop"); 14081a866d615d6e4ee8dcbd49268d2cfb174f5155bChris Lattner return LI->getLoopFor(BB) != CurLoop; 141e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner } 142e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner 143a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner /// sink - When an instruction is found to only be used outside of the loop, 144a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner /// this function moves it to the exit blocks and patches up SSA form as 145a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner /// needed. 146a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner /// 147a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner void sink(Instruction &I); 148a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner 14994170596b715928794a55bc5a1671e3992fd2dc9Chris Lattner /// hoist - When an instruction is found to only use loop invariant operands 15094170596b715928794a55bc5a1671e3992fd2dc9Chris Lattner /// that is safe to hoist, this instruction is called to do the dirty work. 15194170596b715928794a55bc5a1671e3992fd2dc9Chris Lattner /// 1527e70829632f82de15db187845666aaca6e04b792Chris Lattner void hoist(Instruction &I); 153e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner 154a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner /// isSafeToExecuteUnconditionally - Only sink or hoist an instruction if it 155a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner /// is not a trapping instruction or if it is a trapping instruction and is 156a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner /// guaranteed to execute. 1579966c03aad031f738718bed3bc00371e358beb5dTanya Lattner /// 158a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner bool isSafeToExecuteUnconditionally(Instruction &I); 1599966c03aad031f738718bed3bc00371e358beb5dTanya Lattner 16073bfa4aecf25da5d37261c9ad608ba88b20e0860Eli Friedman /// isGuaranteedToExecute - Check that the instruction is guaranteed to 16173bfa4aecf25da5d37261c9ad608ba88b20e0860Eli Friedman /// execute. 16273bfa4aecf25da5d37261c9ad608ba88b20e0860Eli Friedman /// 16373bfa4aecf25da5d37261c9ad608ba88b20e0860Eli Friedman bool isGuaranteedToExecute(Instruction &I); 16473bfa4aecf25da5d37261c9ad608ba88b20e0860Eli Friedman 16594170596b715928794a55bc5a1671e3992fd2dc9Chris Lattner /// pointerInvalidatedByLoop - Return true if the body of this loop may 16694170596b715928794a55bc5a1671e3992fd2dc9Chris Lattner /// store into the memory location pointed to by V. 167fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman /// 1683da848bbda62b25c12335998aaa44ab361f0bf15Dan Gohman bool pointerInvalidatedByLoop(Value *V, uint64_t Size, 169a8702eaf78e70e1eef8a63882ce97ae6d60edf5bDan Gohman const MDNode *TBAAInfo) { 1700252e49f6d6973b6f347c8feafc49e28af27163aChris Lattner // Check to see if any of the basic blocks in CurLoop invalidate *V. 171a8702eaf78e70e1eef8a63882ce97ae6d60edf5bDan Gohman return CurAST->getAliasSetForPointer(V, Size, TBAAInfo).isMod(); 1722e6e741b737960ecd0b68610875050019aac0f07Chris Lattner } 173f5e84aa0887d3fcd752d4a4fa1bb0e526be49f20Chris Lattner 174a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner bool canSinkOrHoistInst(Instruction &I); 175a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner bool isNotUsedInLoop(Instruction &I); 176e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner 177e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner void PromoteAliasSet(AliasSet &AS); 178e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner }; 179e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner} 180e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner 181844731a7f1909f55935e3514c9e713a62d67662eDan Gohmanchar LICM::ID = 0; 1822ab36d350293c77fc8941ce1023e4899df7e3a82Owen AndersonINITIALIZE_PASS_BEGIN(LICM, "licm", "Loop Invariant Code Motion", false, false) 1832ab36d350293c77fc8941ce1023e4899df7e3a82Owen AndersonINITIALIZE_PASS_DEPENDENCY(DominatorTree) 1842ab36d350293c77fc8941ce1023e4899df7e3a82Owen AndersonINITIALIZE_PASS_DEPENDENCY(LoopInfo) 1852ab36d350293c77fc8941ce1023e4899df7e3a82Owen AndersonINITIALIZE_PASS_DEPENDENCY(LoopSimplify) 186aab8e28d5e470711d80276bbf717408c3ab966fdChad RosierINITIALIZE_PASS_DEPENDENCY(TargetLibraryInfo) 1872ab36d350293c77fc8941ce1023e4899df7e3a82Owen AndersonINITIALIZE_AG_DEPENDENCY(AliasAnalysis) 1882ab36d350293c77fc8941ce1023e4899df7e3a82Owen AndersonINITIALIZE_PASS_END(LICM, "licm", "Loop Invariant Code Motion", false, false) 189844731a7f1909f55935e3514c9e713a62d67662eDan Gohman 190394f0441e06dafca29f0752cf400990a5b8fe4b1Daniel DunbarPass *llvm::createLICMPass() { return new LICM(); } 191e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner 1928d246f09cb46fe38aa71d2a4edcd84f30c4bf80eDevang Patel/// Hoist expressions out of the specified loop. Note, alias info for inner 193a3574fb7e5b7b4517eb81c8c76f05e5be05eec1bTobias Grosser/// loop is not preserved so it is not a good idea to run LICM multiple 1948d246f09cb46fe38aa71d2a4edcd84f30c4bf80eDevang Patel/// times on one loop. 19594170596b715928794a55bc5a1671e3992fd2dc9Chris Lattner/// 19654959d6cf68a9b575c98c074babe9867682a7271Devang Patelbool LICM::runOnLoop(Loop *L, LPPassManager &LPM) { 1972e6e741b737960ecd0b68610875050019aac0f07Chris Lattner Changed = false; 198e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner 1992e6e741b737960ecd0b68610875050019aac0f07Chris Lattner // Get our Loop and Alias Analysis information... 2002e6e741b737960ecd0b68610875050019aac0f07Chris Lattner LI = &getAnalysis<LoopInfo>(); 201f5e84aa0887d3fcd752d4a4fa1bb0e526be49f20Chris Lattner AA = &getAnalysis<AliasAnalysis>(); 2023a2b58f3adc5e9f9bffac7ce193f0570aa5a721fOwen Anderson DT = &getAnalysis<DominatorTree>(); 203f5e84aa0887d3fcd752d4a4fa1bb0e526be49f20Chris Lattner 204aab8e28d5e470711d80276bbf717408c3ab966fdChad Rosier TD = getAnalysisIfAvailable<TargetData>(); 205aab8e28d5e470711d80276bbf717408c3ab966fdChad Rosier TLI = &getAnalysis<TargetLibraryInfo>(); 206aab8e28d5e470711d80276bbf717408c3ab966fdChad Rosier 20754959d6cf68a9b575c98c074babe9867682a7271Devang Patel CurAST = new AliasSetTracker(*AA); 2084282e32712da220fd97177772e22ec1ee7e50af2Chris Lattner // Collect Alias info from subloops. 20954959d6cf68a9b575c98c074babe9867682a7271Devang Patel for (Loop::iterator LoopItr = L->begin(), LoopItrE = L->end(); 21054959d6cf68a9b575c98c074babe9867682a7271Devang Patel LoopItr != LoopItrE; ++LoopItr) { 21154959d6cf68a9b575c98c074babe9867682a7271Devang Patel Loop *InnerL = *LoopItr; 2124282e32712da220fd97177772e22ec1ee7e50af2Chris Lattner AliasSetTracker *InnerAST = LoopToAliasSetMap[InnerL]; 2134282e32712da220fd97177772e22ec1ee7e50af2Chris Lattner assert(InnerAST && "Where is my AST?"); 21494170596b715928794a55bc5a1671e3992fd2dc9Chris Lattner 21554959d6cf68a9b575c98c074babe9867682a7271Devang Patel // What if InnerLoop was modified by other passes ? 21654959d6cf68a9b575c98c074babe9867682a7271Devang Patel CurAST->add(*InnerAST); 217a3574fb7e5b7b4517eb81c8c76f05e5be05eec1bTobias Grosser 2184282e32712da220fd97177772e22ec1ee7e50af2Chris Lattner // Once we've incorporated the inner loop's AST into ours, we don't need the 2194282e32712da220fd97177772e22ec1ee7e50af2Chris Lattner // subloop's anymore. 2204282e32712da220fd97177772e22ec1ee7e50af2Chris Lattner delete InnerAST; 2214282e32712da220fd97177772e22ec1ee7e50af2Chris Lattner LoopToAliasSetMap.erase(InnerL); 2222e6e741b737960ecd0b68610875050019aac0f07Chris Lattner } 223a3574fb7e5b7b4517eb81c8c76f05e5be05eec1bTobias Grosser 224e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner CurLoop = L; 225e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner 22699a57216a935a512c418032f590a4660bad9d846Chris Lattner // Get the preheader block to move instructions into... 22799a57216a935a512c418032f590a4660bad9d846Chris Lattner Preheader = L->getLoopPreheader(); 22899a57216a935a512c418032f590a4660bad9d846Chris Lattner 2292e6e741b737960ecd0b68610875050019aac0f07Chris Lattner // Loop over the body of this loop, looking for calls, invokes, and stores. 2300252e49f6d6973b6f347c8feafc49e28af27163aChris Lattner // Because subloops have already been incorporated into AST, we skip blocks in 2312e6e741b737960ecd0b68610875050019aac0f07Chris Lattner // subloops. 2322e6e741b737960ecd0b68610875050019aac0f07Chris Lattner // 2339b78763fce4cb418e7a2e672efb84bac25559b79Dan Gohman for (Loop::block_iterator I = L->block_begin(), E = L->block_end(); 2349b78763fce4cb418e7a2e672efb84bac25559b79Dan Gohman I != E; ++I) { 2359b78763fce4cb418e7a2e672efb84bac25559b79Dan Gohman BasicBlock *BB = *I; 2364282e32712da220fd97177772e22ec1ee7e50af2Chris Lattner if (LI->getLoopFor(BB) == L) // Ignore blocks in subloops. 2379b78763fce4cb418e7a2e672efb84bac25559b79Dan Gohman CurAST->add(*BB); // Incorporate the specified basic block 2389b78763fce4cb418e7a2e672efb84bac25559b79Dan Gohman } 2392e6e741b737960ecd0b68610875050019aac0f07Chris Lattner 240e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner // We want to visit all of the instructions in this loop... that are not parts 241e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner // of our subloops (they have already had their invariants hoisted out of 242e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner // their loop, into this loop, so there is no need to process the BODIES of 243e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner // the subloops). 244e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner // 245952eaee239d6c38f5121ed68277555344c2d6bf0Chris Lattner // Traverse the body of the loop in depth first order on the dominator tree so 246952eaee239d6c38f5121ed68277555344c2d6bf0Chris Lattner // that we are guaranteed to see definitions before we see uses. This allows 247af5cbc82bb6410129425c98bbfc1ffc4c3d0f411Nick Lewycky // us to sink instructions in one pass, without iteration. After sinking 248e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner // instructions, we perform another pass to hoist them out of the loop. 249952eaee239d6c38f5121ed68277555344c2d6bf0Chris Lattner // 25003e896bd6073efc4523d8bcd0239d6ed62126db7Dan Gohman if (L->hasDedicatedExits()) 25103e896bd6073efc4523d8bcd0239d6ed62126db7Dan Gohman SinkRegion(DT->getNode(L->getHeader())); 25203e896bd6073efc4523d8bcd0239d6ed62126db7Dan Gohman if (Preheader) 25303e896bd6073efc4523d8bcd0239d6ed62126db7Dan Gohman HoistRegion(DT->getNode(L->getHeader())); 254e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner 2552e6e741b737960ecd0b68610875050019aac0f07Chris Lattner // Now that all loop invariants have been removed from the loop, promote any 256e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner // memory references to scalars that we can. 257e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner if (!DisablePromotion && Preheader && L->hasDedicatedExits()) { 258e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner // Loop over all of the alias sets in the tracker object. 259e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner for (AliasSetTracker::iterator I = CurAST->begin(), E = CurAST->end(); 260e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner I != E; ++I) 261e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner PromoteAliasSet(*I); 262e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner } 263a3574fb7e5b7b4517eb81c8c76f05e5be05eec1bTobias Grosser 264e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner // Clear out loops state information for the next iteration 265e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner CurLoop = 0; 26699a57216a935a512c418032f590a4660bad9d846Chris Lattner Preheader = 0; 26754959d6cf68a9b575c98c074babe9867682a7271Devang Patel 2684282e32712da220fd97177772e22ec1ee7e50af2Chris Lattner // If this loop is nested inside of another one, save the alias information 2694282e32712da220fd97177772e22ec1ee7e50af2Chris Lattner // for when we process the outer loop. 2704282e32712da220fd97177772e22ec1ee7e50af2Chris Lattner if (L->getParentLoop()) 2714282e32712da220fd97177772e22ec1ee7e50af2Chris Lattner LoopToAliasSetMap[L] = CurAST; 2724282e32712da220fd97177772e22ec1ee7e50af2Chris Lattner else 2734282e32712da220fd97177772e22ec1ee7e50af2Chris Lattner delete CurAST; 27454959d6cf68a9b575c98c074babe9867682a7271Devang Patel return Changed; 275e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner} 276e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner 277e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner/// SinkRegion - Walk the specified region of the CFG (defined by all blocks 278e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner/// dominated by the specified block, and that are in the current loop) in 2793a2b58f3adc5e9f9bffac7ce193f0570aa5a721fOwen Anderson/// reverse depth first order w.r.t the DominatorTree. This allows us to visit 280e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner/// uses before definitions, allowing us to sink a loop body in one pass without 281e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner/// iteration. 282e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner/// 28326042420d642e810f5cdfb2da6156b74aaf80945Devang Patelvoid LICM::SinkRegion(DomTreeNode *N) { 2843a2b58f3adc5e9f9bffac7ce193f0570aa5a721fOwen Anderson assert(N != 0 && "Null dominator tree node?"); 2853a2b58f3adc5e9f9bffac7ce193f0570aa5a721fOwen Anderson BasicBlock *BB = N->getBlock(); 286e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner 287e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner // If this subregion is not in the top level loop at all, exit. 288e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner if (!CurLoop->contains(BB)) return; 289e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner 2900de5cad74d8d2987b92b8d76af3f1eab988b3c7bChris Lattner // We are processing blocks in reverse dfo, so process children first. 29126042420d642e810f5cdfb2da6156b74aaf80945Devang Patel const std::vector<DomTreeNode*> &Children = N->getChildren(); 292e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner for (unsigned i = 0, e = Children.size(); i != e; ++i) 293e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner SinkRegion(Children[i]); 294e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner 295e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner // Only need to process the contents of this block if it is not part of a 296e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner // subloop (which would already have been processed). 297e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner if (inSubLoop(BB)) return; 298e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner 299a3df8a964aa9d0d171fd4f6e491c7d1cf9dee500Chris Lattner for (BasicBlock::iterator II = BB->end(); II != BB->begin(); ) { 300a3df8a964aa9d0d171fd4f6e491c7d1cf9dee500Chris Lattner Instruction &I = *--II; 301a3574fb7e5b7b4517eb81c8c76f05e5be05eec1bTobias Grosser 3020de5cad74d8d2987b92b8d76af3f1eab988b3c7bChris Lattner // If the instruction is dead, we would try to sink it because it isn't used 3030de5cad74d8d2987b92b8d76af3f1eab988b3c7bChris Lattner // in the loop, instead, just delete it. 3040de5cad74d8d2987b92b8d76af3f1eab988b3c7bChris Lattner if (isInstructionTriviallyDead(&I)) { 305cb7f65342291caa3636cb50c0ee04b383cd79f8dChris Lattner DEBUG(dbgs() << "LICM deleting dead inst: " << I << '\n'); 3060de5cad74d8d2987b92b8d76af3f1eab988b3c7bChris Lattner ++II; 3070de5cad74d8d2987b92b8d76af3f1eab988b3c7bChris Lattner CurAST->deleteValue(&I); 3080de5cad74d8d2987b92b8d76af3f1eab988b3c7bChris Lattner I.eraseFromParent(); 3090de5cad74d8d2987b92b8d76af3f1eab988b3c7bChris Lattner Changed = true; 3100de5cad74d8d2987b92b8d76af3f1eab988b3c7bChris Lattner continue; 3110de5cad74d8d2987b92b8d76af3f1eab988b3c7bChris Lattner } 312fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman 313e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner // Check to see if we can sink this instruction to the exit blocks 314e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner // of the loop. We can do this if the all users of the instruction are 315e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner // outside of the loop. In this case, it doesn't even matter if the 316e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner // operands of the instruction are loop invariant. 317e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner // 31870ac2dcb841dc62f08e16f0b0e2cefbf01baa4c5Chris Lattner if (isNotUsedInLoop(I) && canSinkOrHoistInst(I)) { 319a3df8a964aa9d0d171fd4f6e491c7d1cf9dee500Chris Lattner ++II; 320e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner sink(I); 321a3df8a964aa9d0d171fd4f6e491c7d1cf9dee500Chris Lattner } 322e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner } 323e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner} 324e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner 325952eaee239d6c38f5121ed68277555344c2d6bf0Chris Lattner/// HoistRegion - Walk the specified region of the CFG (defined by all blocks 326952eaee239d6c38f5121ed68277555344c2d6bf0Chris Lattner/// dominated by the specified block, and that are in the current loop) in depth 3273a2b58f3adc5e9f9bffac7ce193f0570aa5a721fOwen Anderson/// first order w.r.t the DominatorTree. This allows us to visit definitions 328952eaee239d6c38f5121ed68277555344c2d6bf0Chris Lattner/// before uses, allowing us to hoist a loop body in one pass without iteration. 329952eaee239d6c38f5121ed68277555344c2d6bf0Chris Lattner/// 33026042420d642e810f5cdfb2da6156b74aaf80945Devang Patelvoid LICM::HoistRegion(DomTreeNode *N) { 3313a2b58f3adc5e9f9bffac7ce193f0570aa5a721fOwen Anderson assert(N != 0 && "Null dominator tree node?"); 3323a2b58f3adc5e9f9bffac7ce193f0570aa5a721fOwen Anderson BasicBlock *BB = N->getBlock(); 333952eaee239d6c38f5121ed68277555344c2d6bf0Chris Lattner 334b461373fbcdc5909cc7331fa64791cd039de4bc8Chris Lattner // If this subregion is not in the top level loop at all, exit. 335ed6dfc2856cd44a8aa608a9074eabbf42dd6cadcChris Lattner if (!CurLoop->contains(BB)) return; 336952eaee239d6c38f5121ed68277555344c2d6bf0Chris Lattner 337a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner // Only need to process the contents of this block if it is not part of a 338a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner // subloop (which would already have been processed). 339ed6dfc2856cd44a8aa608a9074eabbf42dd6cadcChris Lattner if (!inSubLoop(BB)) 340a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner for (BasicBlock::iterator II = BB->begin(), E = BB->end(); II != E; ) { 341a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner Instruction &I = *II++; 342fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman 3432ac6e2354ac9961b00fa351635ed04baf7fdd234Chris Lattner // Try constant folding this instruction. If all the operands are 3442ac6e2354ac9961b00fa351635ed04baf7fdd234Chris Lattner // constants, it is technically hoistable, but it would be better to just 3452ac6e2354ac9961b00fa351635ed04baf7fdd234Chris Lattner // fold it. 346aab8e28d5e470711d80276bbf717408c3ab966fdChad Rosier if (Constant *C = ConstantFoldInstruction(&I, TD, TLI)) { 3472ac6e2354ac9961b00fa351635ed04baf7fdd234Chris Lattner DEBUG(dbgs() << "LICM folding inst: " << I << " --> " << *C << '\n'); 3482ac6e2354ac9961b00fa351635ed04baf7fdd234Chris Lattner CurAST->copyValue(&I, C); 3492ac6e2354ac9961b00fa351635ed04baf7fdd234Chris Lattner CurAST->deleteValue(&I); 3502ac6e2354ac9961b00fa351635ed04baf7fdd234Chris Lattner I.replaceAllUsesWith(C); 3512ac6e2354ac9961b00fa351635ed04baf7fdd234Chris Lattner I.eraseFromParent(); 3522ac6e2354ac9961b00fa351635ed04baf7fdd234Chris Lattner continue; 3532ac6e2354ac9961b00fa351635ed04baf7fdd234Chris Lattner } 354a3574fb7e5b7b4517eb81c8c76f05e5be05eec1bTobias Grosser 355e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner // Try hoisting the instruction out to the preheader. We can only do this 356e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner // if all of the operands of the instruction are loop invariant and if it 357e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner // is safe to hoist the instruction. 358e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner // 359adc799112dc180b3cd099038c05101b85d217716Chris Lattner if (CurLoop->hasLoopInvariantOperands(&I) && canSinkOrHoistInst(I) && 360e4365b2e8c79f9b2d564f31fdcc0568da8e5d60fChris Lattner isSafeToExecuteUnconditionally(I)) 3613c80a51cfd5e7187439ce4c051da77ee46e0ff9aChris Lattner hoist(I); 3622ac6e2354ac9961b00fa351635ed04baf7fdd234Chris Lattner } 363952eaee239d6c38f5121ed68277555344c2d6bf0Chris Lattner 36426042420d642e810f5cdfb2da6156b74aaf80945Devang Patel const std::vector<DomTreeNode*> &Children = N->getChildren(); 365952eaee239d6c38f5121ed68277555344c2d6bf0Chris Lattner for (unsigned i = 0, e = Children.size(); i != e; ++i) 36656b7ee20dad7160a117ea0d102fc5432074ce2d0Chris Lattner HoistRegion(Children[i]); 367952eaee239d6c38f5121ed68277555344c2d6bf0Chris Lattner} 368952eaee239d6c38f5121ed68277555344c2d6bf0Chris Lattner 369a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner/// canSinkOrHoistInst - Return true if the hoister and sinker can handle this 370a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner/// instruction. 371a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner/// 372a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattnerbool LICM::canSinkOrHoistInst(Instruction &I) { 373ed6dfc2856cd44a8aa608a9074eabbf42dd6cadcChris Lattner // Loads have extra constraints we have to verify before we can hoist them. 374ed6dfc2856cd44a8aa608a9074eabbf42dd6cadcChris Lattner if (LoadInst *LI = dyn_cast<LoadInst>(&I)) { 37597671565ffd341d1d3291243f9f51edc6b64b065Eli Friedman if (!LI->isUnordered()) 37697671565ffd341d1d3291243f9f51edc6b64b065Eli Friedman return false; // Don't hoist volatile/atomic loads! 377ed6dfc2856cd44a8aa608a9074eabbf42dd6cadcChris Lattner 378967948b4e25cae3de68f38fddaa75d838e676decChris Lattner // Loads from constant memory are always safe to move, even if they end up 379967948b4e25cae3de68f38fddaa75d838e676decChris Lattner // in the same alias set as something that ends up being modified. 380dab249b3b762cff0ff16069b3233e4c885e75347Dan Gohman if (AA->pointsToConstantMemory(LI->getOperand(0))) 381967948b4e25cae3de68f38fddaa75d838e676decChris Lattner return true; 3822d76a7846200fcbe518e6f73291a6cbda8864ea0Pete Cooper if (LI->getMetadata(LI->getContext().getMDKindID("invariant.load"))) 3832d76a7846200fcbe518e6f73291a6cbda8864ea0Pete Cooper return true; 384a3574fb7e5b7b4517eb81c8c76f05e5be05eec1bTobias Grosser 385ed6dfc2856cd44a8aa608a9074eabbf42dd6cadcChris Lattner // Don't hoist loads which have may-aliased stores in loop. 3863da848bbda62b25c12335998aaa44ab361f0bf15Dan Gohman uint64_t Size = 0; 387f3e1d6977ee5fb6b66df314d65e28e2c35d6e244Chris Lattner if (LI->getType()->isSized()) 388fc2a3ed0c9e32cf7edaf5030fa0972b916cc5f0bDan Gohman Size = AA->getTypeStoreSize(LI->getType()); 389a8702eaf78e70e1eef8a63882ce97ae6d60edf5bDan Gohman return !pointerInvalidatedByLoop(LI->getOperand(0), Size, 390a8702eaf78e70e1eef8a63882ce97ae6d60edf5bDan Gohman LI->getMetadata(LLVMContext::MD_tbaa)); 391118dd0ce3d8e4b0a945afc95c9538d5005abacdeChris Lattner } else if (CallInst *CI = dyn_cast<CallInst>(&I)) { 39230a121b4e83c2bed062cc2d89f4b8fc354ac370eEli Friedman // Don't sink or hoist dbg info; it's legal, but not useful. 39330a121b4e83c2bed062cc2d89f4b8fc354ac370eEli Friedman if (isa<DbgInfoIntrinsic>(I)) 39430a121b4e83c2bed062cc2d89f4b8fc354ac370eEli Friedman return false; 39530a121b4e83c2bed062cc2d89f4b8fc354ac370eEli Friedman 39630a121b4e83c2bed062cc2d89f4b8fc354ac370eEli Friedman // Handle simple cases by querying alias analysis. 397dff6710717b159f089c76a07eda074eb6347eb92Duncan Sands AliasAnalysis::ModRefBehavior Behavior = AA->getModRefBehavior(CI); 398dff6710717b159f089c76a07eda074eb6347eb92Duncan Sands if (Behavior == AliasAnalysis::DoesNotAccessMemory) 399dff6710717b159f089c76a07eda074eb6347eb92Duncan Sands return true; 400cd93f3bbb9cf209aff3ffdff9d7c7d05d935b292Dan Gohman if (AliasAnalysis::onlyReadsMemory(Behavior)) { 401dff6710717b159f089c76a07eda074eb6347eb92Duncan Sands // If this call only reads from memory and there are no writes to memory 402dff6710717b159f089c76a07eda074eb6347eb92Duncan Sands // in the loop, we can hoist or sink the call as appropriate. 403dff6710717b159f089c76a07eda074eb6347eb92Duncan Sands bool FoundMod = false; 404dff6710717b159f089c76a07eda074eb6347eb92Duncan Sands for (AliasSetTracker::iterator I = CurAST->begin(), E = CurAST->end(); 405dff6710717b159f089c76a07eda074eb6347eb92Duncan Sands I != E; ++I) { 406dff6710717b159f089c76a07eda074eb6347eb92Duncan Sands AliasSet &AS = *I; 407dff6710717b159f089c76a07eda074eb6347eb92Duncan Sands if (!AS.isForwardingAliasSet() && AS.isMod()) { 408dff6710717b159f089c76a07eda074eb6347eb92Duncan Sands FoundMod = true; 409dff6710717b159f089c76a07eda074eb6347eb92Duncan Sands break; 410118dd0ce3d8e4b0a945afc95c9538d5005abacdeChris Lattner } 411118dd0ce3d8e4b0a945afc95c9538d5005abacdeChris Lattner } 412dff6710717b159f089c76a07eda074eb6347eb92Duncan Sands if (!FoundMod) return true; 413118dd0ce3d8e4b0a945afc95c9538d5005abacdeChris Lattner } 414118dd0ce3d8e4b0a945afc95c9538d5005abacdeChris Lattner 415118dd0ce3d8e4b0a945afc95c9538d5005abacdeChris Lattner // FIXME: This should use mod/ref information to see if we can hoist or sink 416118dd0ce3d8e4b0a945afc95c9538d5005abacdeChris Lattner // the call. 417fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman 418118dd0ce3d8e4b0a945afc95c9538d5005abacdeChris Lattner return false; 419ed6dfc2856cd44a8aa608a9074eabbf42dd6cadcChris Lattner } 420ed6dfc2856cd44a8aa608a9074eabbf42dd6cadcChris Lattner 4213da59db637a887474c1b1346c1f3ccf53b6c4663Reid Spencer // Otherwise these instructions are hoistable/sinkable 422832254e1c2387c0cbeb0a820b8315fbe85cb003aReid Spencer return isa<BinaryOperator>(I) || isa<CastInst>(I) || 423d8af90c1da64b81a7aa167b5adcc1e81b0741252Dan Gohman isa<SelectInst>(I) || isa<GetElementPtrInst>(I) || isa<CmpInst>(I) || 424d8af90c1da64b81a7aa167b5adcc1e81b0741252Dan Gohman isa<InsertElementInst>(I) || isa<ExtractElementInst>(I) || 425d8af90c1da64b81a7aa167b5adcc1e81b0741252Dan Gohman isa<ShuffleVectorInst>(I); 426a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner} 427a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner 428a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner/// isNotUsedInLoop - Return true if the only users of this instruction are 429a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner/// outside of the loop. If this is true, we can sink the instruction to the 430a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner/// exit blocks of the loop. 431a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner/// 432a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattnerbool LICM::isNotUsedInLoop(Instruction &I) { 433ea9403f2aa078e840a49792d906390395f0cd2f6Chris Lattner for (Value::use_iterator UI = I.use_begin(), E = I.use_end(); UI != E; ++UI) { 434ea9403f2aa078e840a49792d906390395f0cd2f6Chris Lattner Instruction *User = cast<Instruction>(*UI); 435ea9403f2aa078e840a49792d906390395f0cd2f6Chris Lattner if (PHINode *PN = dyn_cast<PHINode>(User)) { 436ea9403f2aa078e840a49792d906390395f0cd2f6Chris Lattner // PHI node uses occur in predecessor blocks! 437ea9403f2aa078e840a49792d906390395f0cd2f6Chris Lattner for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) 438ea9403f2aa078e840a49792d906390395f0cd2f6Chris Lattner if (PN->getIncomingValue(i) == &I) 439ea9403f2aa078e840a49792d906390395f0cd2f6Chris Lattner if (CurLoop->contains(PN->getIncomingBlock(i))) 440ea9403f2aa078e840a49792d906390395f0cd2f6Chris Lattner return false; 44192329c7fbe572892c17aa2d2542a10e3ea16132fDan Gohman } else if (CurLoop->contains(User)) { 442a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner return false; 443ea9403f2aa078e840a49792d906390395f0cd2f6Chris Lattner } 444ea9403f2aa078e840a49792d906390395f0cd2f6Chris Lattner } 445a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner return true; 446a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner} 447a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner 448a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner 449a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner/// sink - When an instruction is found to only be used outside of the loop, 450a3df8a964aa9d0d171fd4f6e491c7d1cf9dee500Chris Lattner/// this function moves it to the exit blocks and patches up SSA form as needed. 451a3df8a964aa9d0d171fd4f6e491c7d1cf9dee500Chris Lattner/// This method is guaranteed to remove the original instruction from its 452a3df8a964aa9d0d171fd4f6e491c7d1cf9dee500Chris Lattner/// position, and may either delete it or move it to outside of the loop. 453a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner/// 454a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattnervoid LICM::sink(Instruction &I) { 45539a383124b70dda1fea18288235114029ede76cfNick Lewycky DEBUG(dbgs() << "LICM sinking instruction: " << I << "\n"); 456a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner 457b7211a2ce13a0365e0e1dd2f27adda2ee3d1288bDevang Patel SmallVector<BasicBlock*, 8> ExitBlocks; 458d7bc19dfee3f2ce8e9c8b9193bdfb93a67008a39Chris Lattner CurLoop->getUniqueExitBlocks(ExitBlocks); 459df45bd3803ae0965a83cd1f30ee051b9f43e73ddChris Lattner 460df45bd3803ae0965a83cd1f30ee051b9f43e73ddChris Lattner if (isa<LoadInst>(I)) ++NumMovedLoads; 461118dd0ce3d8e4b0a945afc95c9538d5005abacdeChris Lattner else if (isa<CallInst>(I)) ++NumMovedCalls; 462df45bd3803ae0965a83cd1f30ee051b9f43e73ddChris Lattner ++NumSunk; 463df45bd3803ae0965a83cd1f30ee051b9f43e73ddChris Lattner Changed = true; 464df45bd3803ae0965a83cd1f30ee051b9f43e73ddChris Lattner 465a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner // The case where there is only a single exit node of this loop is common 466a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner // enough that we handle it as a special (more efficient) case. It is more 467a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner // efficient to handle because there are no PHI nodes that need to be placed. 468a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner if (ExitBlocks.size() == 1) { 46930a121b4e83c2bed062cc2d89f4b8fc354ac370eEli Friedman if (!DT->dominates(I.getParent(), ExitBlocks[0])) { 470a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner // Instruction is not used, just delete it. 4712741c971044d2165be572749b94398043caccfebChris Lattner CurAST->deleteValue(&I); 4721bf5ebc7be0d5b05e4175c7adb767b38896adef1Devang Patel // If I has users in unreachable blocks, eliminate. 473228ebd0f4cf9207d32d61ef4b11b81736895dc09Devang Patel // If I is not void type then replaceAllUsesWith undef. 474228ebd0f4cf9207d32d61ef4b11b81736895dc09Devang Patel // This allows ValueHandlers and custom metadata to adjust itself. 475a6a36f59b42703c5da0f68e0db37605c2e1633bfChris Lattner if (!I.use_empty()) 476228ebd0f4cf9207d32d61ef4b11b81736895dc09Devang Patel I.replaceAllUsesWith(UndefValue::get(I.getType())); 4773c80a51cfd5e7187439ce4c051da77ee46e0ff9aChris Lattner I.eraseFromParent(); 478a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner } else { 479a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner // Move the instruction to the start of the exit block, after any PHI 480a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner // nodes in it. 48126665de4f7ab03d651f626bddb925724a2816a18Bill Wendling I.moveBefore(ExitBlocks[0]->getFirstInsertionPt()); 4824282e32712da220fd97177772e22ec1ee7e50af2Chris Lattner 4834282e32712da220fd97177772e22ec1ee7e50af2Chris Lattner // This instruction is no longer in the AST for the current loop, because 4844282e32712da220fd97177772e22ec1ee7e50af2Chris Lattner // we just sunk it out of the loop. If we just sunk it into an outer 4854282e32712da220fd97177772e22ec1ee7e50af2Chris Lattner // loop, we will rediscover the operation when we process it. 4864282e32712da220fd97177772e22ec1ee7e50af2Chris Lattner CurAST->deleteValue(&I); 487a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner } 488d7bc19dfee3f2ce8e9c8b9193bdfb93a67008a39Chris Lattner return; 489d7bc19dfee3f2ce8e9c8b9193bdfb93a67008a39Chris Lattner } 490a3574fb7e5b7b4517eb81c8c76f05e5be05eec1bTobias Grosser 491d7bc19dfee3f2ce8e9c8b9193bdfb93a67008a39Chris Lattner if (ExitBlocks.empty()) { 492a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner // The instruction is actually dead if there ARE NO exit blocks. 4932741c971044d2165be572749b94398043caccfebChris Lattner CurAST->deleteValue(&I); 4941bf5ebc7be0d5b05e4175c7adb767b38896adef1Devang Patel // If I has users in unreachable blocks, eliminate. 495228ebd0f4cf9207d32d61ef4b11b81736895dc09Devang Patel // If I is not void type then replaceAllUsesWith undef. 496228ebd0f4cf9207d32d61ef4b11b81736895dc09Devang Patel // This allows ValueHandlers and custom metadata to adjust itself. 497a6a36f59b42703c5da0f68e0db37605c2e1633bfChris Lattner if (!I.use_empty()) 498228ebd0f4cf9207d32d61ef4b11b81736895dc09Devang Patel I.replaceAllUsesWith(UndefValue::get(I.getType())); 4993c80a51cfd5e7187439ce4c051da77ee46e0ff9aChris Lattner I.eraseFromParent(); 500d7bc19dfee3f2ce8e9c8b9193bdfb93a67008a39Chris Lattner return; 501d7bc19dfee3f2ce8e9c8b9193bdfb93a67008a39Chris Lattner } 502a3574fb7e5b7b4517eb81c8c76f05e5be05eec1bTobias Grosser 503a6a36f59b42703c5da0f68e0db37605c2e1633bfChris Lattner // Otherwise, if we have multiple exits, use the SSAUpdater to do all of the 504a6a36f59b42703c5da0f68e0db37605c2e1633bfChris Lattner // hard work of inserting PHI nodes as necessary. 505a6a36f59b42703c5da0f68e0db37605c2e1633bfChris Lattner SmallVector<PHINode*, 8> NewPHIs; 506a6a36f59b42703c5da0f68e0db37605c2e1633bfChris Lattner SSAUpdater SSA(&NewPHIs); 507a3574fb7e5b7b4517eb81c8c76f05e5be05eec1bTobias Grosser 508a6a36f59b42703c5da0f68e0db37605c2e1633bfChris Lattner if (!I.use_empty()) 509fc6e29d4ab52b7d3efd83846ed495a9ca7e51e49Duncan Sands SSA.Initialize(I.getType(), I.getName()); 510a3574fb7e5b7b4517eb81c8c76f05e5be05eec1bTobias Grosser 511a6a36f59b42703c5da0f68e0db37605c2e1633bfChris Lattner // Insert a copy of the instruction in each exit block of the loop that is 512a6a36f59b42703c5da0f68e0db37605c2e1633bfChris Lattner // dominated by the instruction. Each exit block is known to only be in the 513a6a36f59b42703c5da0f68e0db37605c2e1633bfChris Lattner // ExitBlocks list once. 514a6a36f59b42703c5da0f68e0db37605c2e1633bfChris Lattner BasicBlock *InstOrigBB = I.getParent(); 515d7bc19dfee3f2ce8e9c8b9193bdfb93a67008a39Chris Lattner unsigned NumInserted = 0; 516a3574fb7e5b7b4517eb81c8c76f05e5be05eec1bTobias Grosser 517d7bc19dfee3f2ce8e9c8b9193bdfb93a67008a39Chris Lattner for (unsigned i = 0, e = ExitBlocks.size(); i != e; ++i) { 518d7bc19dfee3f2ce8e9c8b9193bdfb93a67008a39Chris Lattner BasicBlock *ExitBlock = ExitBlocks[i]; 519a3574fb7e5b7b4517eb81c8c76f05e5be05eec1bTobias Grosser 52083fc584ea811aca780d965258c49db72a3ee8b1dChris Lattner if (!DT->dominates(InstOrigBB, ExitBlock)) 521d7bc19dfee3f2ce8e9c8b9193bdfb93a67008a39Chris Lattner continue; 522a3574fb7e5b7b4517eb81c8c76f05e5be05eec1bTobias Grosser 523a6a36f59b42703c5da0f68e0db37605c2e1633bfChris Lattner // Insert the code after the last PHI node. 52426665de4f7ab03d651f626bddb925724a2816a18Bill Wendling BasicBlock::iterator InsertPt = ExitBlock->getFirstInsertionPt(); 525a3574fb7e5b7b4517eb81c8c76f05e5be05eec1bTobias Grosser 526d7bc19dfee3f2ce8e9c8b9193bdfb93a67008a39Chris Lattner // If this is the first exit block processed, just move the original 527d7bc19dfee3f2ce8e9c8b9193bdfb93a67008a39Chris Lattner // instruction, otherwise clone the original instruction and insert 528d7bc19dfee3f2ce8e9c8b9193bdfb93a67008a39Chris Lattner // the copy. 529d7bc19dfee3f2ce8e9c8b9193bdfb93a67008a39Chris Lattner Instruction *New; 530a6a36f59b42703c5da0f68e0db37605c2e1633bfChris Lattner if (NumInserted++ == 0) { 531a6a36f59b42703c5da0f68e0db37605c2e1633bfChris Lattner I.moveBefore(InsertPt); 532d7bc19dfee3f2ce8e9c8b9193bdfb93a67008a39Chris Lattner New = &I; 533d7bc19dfee3f2ce8e9c8b9193bdfb93a67008a39Chris Lattner } else { 534d7bc19dfee3f2ce8e9c8b9193bdfb93a67008a39Chris Lattner New = I.clone(); 535d7bc19dfee3f2ce8e9c8b9193bdfb93a67008a39Chris Lattner if (!I.getName().empty()) 536d7bc19dfee3f2ce8e9c8b9193bdfb93a67008a39Chris Lattner New->setName(I.getName()+".le"); 537d7bc19dfee3f2ce8e9c8b9193bdfb93a67008a39Chris Lattner ExitBlock->getInstList().insert(InsertPt, New); 538a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner } 539a3574fb7e5b7b4517eb81c8c76f05e5be05eec1bTobias Grosser 540a6a36f59b42703c5da0f68e0db37605c2e1633bfChris Lattner // Now that we have inserted the instruction, inform SSAUpdater. 541a6a36f59b42703c5da0f68e0db37605c2e1633bfChris Lattner if (!I.use_empty()) 542a6a36f59b42703c5da0f68e0db37605c2e1633bfChris Lattner SSA.AddAvailableValue(ExitBlock, New); 543d7bc19dfee3f2ce8e9c8b9193bdfb93a67008a39Chris Lattner } 544a3574fb7e5b7b4517eb81c8c76f05e5be05eec1bTobias Grosser 545c955d212a8c060d7082fe975fd65fcbc9263853aEli Friedman // If the instruction doesn't dominate any exit blocks, it must be dead. 546c955d212a8c060d7082fe975fd65fcbc9263853aEli Friedman if (NumInserted == 0) { 547c955d212a8c060d7082fe975fd65fcbc9263853aEli Friedman CurAST->deleteValue(&I); 548c955d212a8c060d7082fe975fd65fcbc9263853aEli Friedman if (!I.use_empty()) 549c955d212a8c060d7082fe975fd65fcbc9263853aEli Friedman I.replaceAllUsesWith(UndefValue::get(I.getType())); 550c955d212a8c060d7082fe975fd65fcbc9263853aEli Friedman I.eraseFromParent(); 551c955d212a8c060d7082fe975fd65fcbc9263853aEli Friedman return; 552c955d212a8c060d7082fe975fd65fcbc9263853aEli Friedman } 553a3574fb7e5b7b4517eb81c8c76f05e5be05eec1bTobias Grosser 554a6a36f59b42703c5da0f68e0db37605c2e1633bfChris Lattner // Next, rewrite uses of the instruction, inserting PHI nodes as needed. 555a6a36f59b42703c5da0f68e0db37605c2e1633bfChris Lattner for (Value::use_iterator UI = I.use_begin(), UE = I.use_end(); UI != UE; ) { 556a6a36f59b42703c5da0f68e0db37605c2e1633bfChris Lattner // Grab the use before incrementing the iterator. 557a6a36f59b42703c5da0f68e0db37605c2e1633bfChris Lattner Use &U = UI.getUse(); 558a6a36f59b42703c5da0f68e0db37605c2e1633bfChris Lattner // Increment the iterator before removing the use from the list. 559a6a36f59b42703c5da0f68e0db37605c2e1633bfChris Lattner ++UI; 560a6a36f59b42703c5da0f68e0db37605c2e1633bfChris Lattner SSA.RewriteUseAfterInsertions(U); 561a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner } 562a3574fb7e5b7b4517eb81c8c76f05e5be05eec1bTobias Grosser 563a6a36f59b42703c5da0f68e0db37605c2e1633bfChris Lattner // Update CurAST for NewPHIs if I had pointer type. 564a6a36f59b42703c5da0f68e0db37605c2e1633bfChris Lattner if (I.getType()->isPointerTy()) 565a6a36f59b42703c5da0f68e0db37605c2e1633bfChris Lattner for (unsigned i = 0, e = NewPHIs.size(); i != e; ++i) 5669c282011e6b7a6e23a3a163ec9c865890449e8dcChris Lattner CurAST->copyValue(&I, NewPHIs[i]); 567a3574fb7e5b7b4517eb81c8c76f05e5be05eec1bTobias Grosser 56898917503c702e16f35ccdec3f6b4c48e5c4759acChris Lattner // Finally, remove the instruction from CurAST. It is no longer in the loop. 56998917503c702e16f35ccdec3f6b4c48e5c4759acChris Lattner CurAST->deleteValue(&I); 570a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner} 571952eaee239d6c38f5121ed68277555344c2d6bf0Chris Lattner 57294170596b715928794a55bc5a1671e3992fd2dc9Chris Lattner/// hoist - When an instruction is found to only use loop invariant operands 57394170596b715928794a55bc5a1671e3992fd2dc9Chris Lattner/// that is safe to hoist, this instruction is called to do the dirty work. 57494170596b715928794a55bc5a1671e3992fd2dc9Chris Lattner/// 575a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattnervoid LICM::hoist(Instruction &I) { 576f15826999bc560ee6f67cff5ecd71bf9cce7a7aaDavid Greene DEBUG(dbgs() << "LICM hoisting to " << Preheader->getName() << ": " 57767d1d1f8322bdc460158888cd233be8d1cb1d4abEvan Cheng << I << "\n"); 578ed6dfc2856cd44a8aa608a9074eabbf42dd6cadcChris Lattner 579d9a5daeb7719c83136c0dc43d6ef732402d1a1b5Chris Lattner // Move the new node to the Preheader, before its terminator. 580d9a5daeb7719c83136c0dc43d6ef732402d1a1b5Chris Lattner I.moveBefore(Preheader->getTerminator()); 581fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman 582a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner if (isa<LoadInst>(I)) ++NumMovedLoads; 583118dd0ce3d8e4b0a945afc95c9538d5005abacdeChris Lattner else if (isa<CallInst>(I)) ++NumMovedCalls; 5849646e6b6af1f924f9366a2bffc6dde102f84d231Chris Lattner ++NumHoisted; 585e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner Changed = true; 586e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner} 587e0e734eea052a4e8372e6f430ef41149128ba0a6Chris Lattner 588a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner/// isSafeToExecuteUnconditionally - Only sink or hoist an instruction if it is 589a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner/// not a trapping instruction or if it is a trapping instruction and is 590a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner/// guaranteed to execute. 5919966c03aad031f738718bed3bc00371e358beb5dTanya Lattner/// 592a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattnerbool LICM::isSafeToExecuteUnconditionally(Instruction &Inst) { 59392094b4d928119eceac1484331acffe950f4651cChris Lattner // If it is not a trapping instruction, it is always safe to hoist. 5940b79a7727d68a507837e827803859424cf3d997bEli Friedman if (Inst.isSafeToSpeculativelyExecute()) 5950b79a7727d68a507837e827803859424cf3d997bEli Friedman return true; 596fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman 59773bfa4aecf25da5d37261c9ad608ba88b20e0860Eli Friedman return isGuaranteedToExecute(Inst); 59873bfa4aecf25da5d37261c9ad608ba88b20e0860Eli Friedman} 59973bfa4aecf25da5d37261c9ad608ba88b20e0860Eli Friedman 60073bfa4aecf25da5d37261c9ad608ba88b20e0860Eli Friedmanbool LICM::isGuaranteedToExecute(Instruction &Inst) { 60192094b4d928119eceac1484331acffe950f4651cChris Lattner // Otherwise we have to check to make sure that the instruction dominates all 60292094b4d928119eceac1484331acffe950f4651cChris Lattner // of the exit blocks. If it doesn't, then there is a path out of the loop 60392094b4d928119eceac1484331acffe950f4651cChris Lattner // which does not execute this instruction, so we can't hoist it. 60492094b4d928119eceac1484331acffe950f4651cChris Lattner 60592094b4d928119eceac1484331acffe950f4651cChris Lattner // If the instruction is in the header block for the loop (which is very 60692094b4d928119eceac1484331acffe950f4651cChris Lattner // common), it is always guaranteed to dominate the exit blocks. Since this 60792094b4d928119eceac1484331acffe950f4651cChris Lattner // is a common case, and can save some work, check it now. 608a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner if (Inst.getParent() == CurLoop->getHeader()) 60992094b4d928119eceac1484331acffe950f4651cChris Lattner return true; 61092094b4d928119eceac1484331acffe950f4651cChris Lattner 61192094b4d928119eceac1484331acffe950f4651cChris Lattner // Get the exit blocks for the current loop. 612b7211a2ce13a0365e0e1dd2f27adda2ee3d1288bDevang Patel SmallVector<BasicBlock*, 8> ExitBlocks; 6135fa802fe279f10f402e039bc931aa57c0e424bf5Chris Lattner CurLoop->getExitBlocks(ExitBlocks); 6149966c03aad031f738718bed3bc00371e358beb5dTanya Lattner 61583fc584ea811aca780d965258c49db72a3ee8b1dChris Lattner // Verify that the block dominates each of the exit blocks of the loop. 616a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner for (unsigned i = 0, e = ExitBlocks.size(); i != e; ++i) 61783fc584ea811aca780d965258c49db72a3ee8b1dChris Lattner if (!DT->dominates(Inst.getParent(), ExitBlocks[i])) 618a2706518f9cc34358cba1072f78235aa091d6d93Chris Lattner return false; 619fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman 6209966c03aad031f738718bed3bc00371e358beb5dTanya Lattner return true; 6219966c03aad031f738718bed3bc00371e358beb5dTanya Lattner} 6229966c03aad031f738718bed3bc00371e358beb5dTanya Lattner 623deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattnernamespace { 624deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner class LoopPromoter : public LoadAndStorePromoter { 625deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner Value *SomePtr; // Designated pointer to store to. 626deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner SmallPtrSet<Value*, 4> &PointerMustAliases; 627deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner SmallVectorImpl<BasicBlock*> &LoopExitBlocks; 628deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner AliasSetTracker &AST; 629dda266d4ce34bafed3b213ef0370cd9209159ba5Eli Friedman DebugLoc DL; 630df7102b7d6d472c58d5f0fcc16e0ebf07c8deb55Tobias Grosser int Alignment; 631deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner public: 632deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner LoopPromoter(Value *SP, 633deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner const SmallVectorImpl<Instruction*> &Insts, SSAUpdater &S, 634deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner SmallPtrSet<Value*, 4> &PMA, 635dda266d4ce34bafed3b213ef0370cd9209159ba5Eli Friedman SmallVectorImpl<BasicBlock*> &LEB, AliasSetTracker &ast, 636df7102b7d6d472c58d5f0fcc16e0ebf07c8deb55Tobias Grosser DebugLoc dl, int alignment) 637231a5ab746ca12000aa57208869a98f78781aa6bDevang Patel : LoadAndStorePromoter(Insts, S), SomePtr(SP), 638df7102b7d6d472c58d5f0fcc16e0ebf07c8deb55Tobias Grosser PointerMustAliases(PMA), LoopExitBlocks(LEB), AST(ast), DL(dl), 639df7102b7d6d472c58d5f0fcc16e0ebf07c8deb55Tobias Grosser Alignment(alignment) {} 640a3574fb7e5b7b4517eb81c8c76f05e5be05eec1bTobias Grosser 641deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner virtual bool isInstInList(Instruction *I, 642deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner const SmallVectorImpl<Instruction*> &) const { 643deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner Value *Ptr; 644deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner if (LoadInst *LI = dyn_cast<LoadInst>(I)) 645deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner Ptr = LI->getOperand(0); 646deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner else 647deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner Ptr = cast<StoreInst>(I)->getPointerOperand(); 648deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner return PointerMustAliases.count(Ptr); 649deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner } 650a3574fb7e5b7b4517eb81c8c76f05e5be05eec1bTobias Grosser 651deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner virtual void doExtraRewritesBeforeFinalDeletion() const { 652deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner // Insert stores after in the loop exit blocks. Each exit block gets a 653deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner // store of the live-out values that feed them. Since we've already told 654deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner // the SSA updater about the defs in the loop and the preheader 655deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner // definition, it is all set and we can start using it. 656deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner for (unsigned i = 0, e = LoopExitBlocks.size(); i != e; ++i) { 657deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner BasicBlock *ExitBlock = LoopExitBlocks[i]; 658deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner Value *LiveInValue = SSA.GetValueInMiddleOfBlock(ExitBlock); 65926665de4f7ab03d651f626bddb925724a2816a18Bill Wendling Instruction *InsertPos = ExitBlock->getFirstInsertionPt(); 660dda266d4ce34bafed3b213ef0370cd9209159ba5Eli Friedman StoreInst *NewSI = new StoreInst(LiveInValue, SomePtr, InsertPos); 661df7102b7d6d472c58d5f0fcc16e0ebf07c8deb55Tobias Grosser NewSI->setAlignment(Alignment); 662dda266d4ce34bafed3b213ef0370cd9209159ba5Eli Friedman NewSI->setDebugLoc(DL); 663deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner } 664deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner } 665deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner 666deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner virtual void replaceLoadWithValue(LoadInst *LI, Value *V) const { 667deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner // Update alias analysis. 668deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner AST.copyValue(LI, V); 669deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner } 670deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner virtual void instructionDeleted(Instruction *I) const { 671deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner AST.deleteValue(I); 672deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner } 673deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner }; 674deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner} // end anon namespace 675deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner 676e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner/// PromoteAliasSet - Try to promote memory values to scalars by sinking 6772e6e741b737960ecd0b68610875050019aac0f07Chris Lattner/// stores out of the loop and moving loads to before the loop. We do this by 6782e6e741b737960ecd0b68610875050019aac0f07Chris Lattner/// looping over the stores in the loop, looking for stores to Must pointers 679e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner/// which are loop invariant. 6802e6e741b737960ecd0b68610875050019aac0f07Chris Lattner/// 681e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattnervoid LICM::PromoteAliasSet(AliasSet &AS) { 682e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner // We can promote this alias set if it has a store, if it is a "Must" alias 683e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner // set, if the pointer is loop invariant, and if we are not eliminating any 684e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner // volatile loads or stores. 685e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner if (AS.isForwardingAliasSet() || !AS.isMod() || !AS.isMustAlias() || 686e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner AS.isVolatile() || !CurLoop->isLoopInvariant(AS.begin()->getValue())) 687e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner return; 688a3574fb7e5b7b4517eb81c8c76f05e5be05eec1bTobias Grosser 689e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner assert(!AS.empty() && 690e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner "Must alias set should have at least one pointer element in it!"); 691e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner Value *SomePtr = AS.begin()->getValue(); 692fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman 693e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner // It isn't safe to promote a load/store from the loop if the load/store is 694e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner // conditional. For example, turning: 6952e6e741b737960ecd0b68610875050019aac0f07Chris Lattner // 696e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner // for () { if (c) *P += 1; } 6972e6e741b737960ecd0b68610875050019aac0f07Chris Lattner // 698e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner // into: 699e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner // 700e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner // tmp = *P; for () { if (c) tmp +=1; } *P = tmp; 701e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner // 702e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner // is not safe, because *P may only be valid to access if 'c' is true. 703a3574fb7e5b7b4517eb81c8c76f05e5be05eec1bTobias Grosser // 704e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner // It is safe to promote P if all uses are direct load/stores and if at 705e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner // least one is guaranteed to be executed. 706e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner bool GuaranteedToExecute = false; 707df7102b7d6d472c58d5f0fcc16e0ebf07c8deb55Tobias Grosser 708e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner SmallVector<Instruction*, 64> LoopUses; 709e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner SmallPtrSet<Value*, 4> PointerMustAliases; 710e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner 711df7102b7d6d472c58d5f0fcc16e0ebf07c8deb55Tobias Grosser // We start with an alignment of one and try to find instructions that allow 712df7102b7d6d472c58d5f0fcc16e0ebf07c8deb55Tobias Grosser // us to prove better alignment. 713df7102b7d6d472c58d5f0fcc16e0ebf07c8deb55Tobias Grosser unsigned Alignment = 1; 714df7102b7d6d472c58d5f0fcc16e0ebf07c8deb55Tobias Grosser 715e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner // Check that all of the pointers in the alias set have the same type. We 716e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner // cannot (yet) promote a memory location that is loaded and stored in 717e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner // different sizes. 718e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner for (AliasSet::iterator ASI = AS.begin(), E = AS.end(); ASI != E; ++ASI) { 719e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner Value *ASIV = ASI->getValue(); 720e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner PointerMustAliases.insert(ASIV); 721a3574fb7e5b7b4517eb81c8c76f05e5be05eec1bTobias Grosser 72229d929363d9b8a2c0d40c5d50fec022c736cb654Chris Lattner // Check that all of the pointers in the alias set have the same type. We 72329d929363d9b8a2c0d40c5d50fec022c736cb654Chris Lattner // cannot (yet) promote a memory location that is loaded and stored in 72429d929363d9b8a2c0d40c5d50fec022c736cb654Chris Lattner // different sizes. 725e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner if (SomePtr->getType() != ASIV->getType()) 726e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner return; 727a3574fb7e5b7b4517eb81c8c76f05e5be05eec1bTobias Grosser 728e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner for (Value::use_iterator UI = ASIV->use_begin(), UE = ASIV->use_end(); 72919d9d4364e514f316f8757b577bb8bb33c22dbfcChris Lattner UI != UE; ++UI) { 730e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner // Ignore instructions that are outside the loop. 73129d929363d9b8a2c0d40c5d50fec022c736cb654Chris Lattner Instruction *Use = dyn_cast<Instruction>(*UI); 73292329c7fbe572892c17aa2d2542a10e3ea16132fDan Gohman if (!Use || !CurLoop->contains(Use)) 73329d929363d9b8a2c0d40c5d50fec022c736cb654Chris Lattner continue; 734a3574fb7e5b7b4517eb81c8c76f05e5be05eec1bTobias Grosser 735e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner // If there is an non-load/store instruction in the loop, we can't promote 736e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner // it. 73797671565ffd341d1d3291243f9f51edc6b64b065Eli Friedman if (LoadInst *load = dyn_cast<LoadInst>(Use)) { 73897671565ffd341d1d3291243f9f51edc6b64b065Eli Friedman assert(!load->isVolatile() && "AST broken"); 73997671565ffd341d1d3291243f9f51edc6b64b065Eli Friedman if (!load->isSimple()) 74097671565ffd341d1d3291243f9f51edc6b64b065Eli Friedman return; 741df7102b7d6d472c58d5f0fcc16e0ebf07c8deb55Tobias Grosser } else if (StoreInst *store = dyn_cast<StoreInst>(Use)) { 7421dec0d27048725cf73f73ce4f0bb97ca78255f97Chris Lattner // Stores *of* the pointer are not interesting, only stores *to* the 7431dec0d27048725cf73f73ce4f0bb97ca78255f97Chris Lattner // pointer. 7441dec0d27048725cf73f73ce4f0bb97ca78255f97Chris Lattner if (Use->getOperand(1) != ASIV) 7451dec0d27048725cf73f73ce4f0bb97ca78255f97Chris Lattner continue; 74697671565ffd341d1d3291243f9f51edc6b64b065Eli Friedman assert(!store->isVolatile() && "AST broken"); 74797671565ffd341d1d3291243f9f51edc6b64b065Eli Friedman if (!store->isSimple()) 74897671565ffd341d1d3291243f9f51edc6b64b065Eli Friedman return; 749df7102b7d6d472c58d5f0fcc16e0ebf07c8deb55Tobias Grosser 75073bfa4aecf25da5d37261c9ad608ba88b20e0860Eli Friedman // Note that we only check GuaranteedToExecute inside the store case 75173bfa4aecf25da5d37261c9ad608ba88b20e0860Eli Friedman // so that we do not introduce stores where they did not exist before 75273bfa4aecf25da5d37261c9ad608ba88b20e0860Eli Friedman // (which would break the LLVM concurrency model). 75373bfa4aecf25da5d37261c9ad608ba88b20e0860Eli Friedman 75473bfa4aecf25da5d37261c9ad608ba88b20e0860Eli Friedman // If the alignment of this instruction allows us to specify a more 75573bfa4aecf25da5d37261c9ad608ba88b20e0860Eli Friedman // restrictive (and performant) alignment and if we are sure this 75673bfa4aecf25da5d37261c9ad608ba88b20e0860Eli Friedman // instruction will be executed, update the alignment. 75773bfa4aecf25da5d37261c9ad608ba88b20e0860Eli Friedman // Larger is better, with the exception of 0 being the best alignment. 75897671565ffd341d1d3291243f9f51edc6b64b065Eli Friedman unsigned InstAlignment = store->getAlignment(); 75973bfa4aecf25da5d37261c9ad608ba88b20e0860Eli Friedman if ((InstAlignment > Alignment || InstAlignment == 0) 76073bfa4aecf25da5d37261c9ad608ba88b20e0860Eli Friedman && (Alignment != 0)) 76173bfa4aecf25da5d37261c9ad608ba88b20e0860Eli Friedman if (isGuaranteedToExecute(*Use)) { 76273bfa4aecf25da5d37261c9ad608ba88b20e0860Eli Friedman GuaranteedToExecute = true; 76373bfa4aecf25da5d37261c9ad608ba88b20e0860Eli Friedman Alignment = InstAlignment; 76473bfa4aecf25da5d37261c9ad608ba88b20e0860Eli Friedman } 76573bfa4aecf25da5d37261c9ad608ba88b20e0860Eli Friedman 76673bfa4aecf25da5d37261c9ad608ba88b20e0860Eli Friedman if (!GuaranteedToExecute) 76773bfa4aecf25da5d37261c9ad608ba88b20e0860Eli Friedman GuaranteedToExecute = isGuaranteedToExecute(*Use); 768df7102b7d6d472c58d5f0fcc16e0ebf07c8deb55Tobias Grosser 76973bfa4aecf25da5d37261c9ad608ba88b20e0860Eli Friedman } else 77073bfa4aecf25da5d37261c9ad608ba88b20e0860Eli Friedman return; // Not a load or store. 771a3574fb7e5b7b4517eb81c8c76f05e5be05eec1bTobias Grosser 772e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner LoopUses.push_back(Use); 77329d929363d9b8a2c0d40c5d50fec022c736cb654Chris Lattner } 774e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner } 775df7102b7d6d472c58d5f0fcc16e0ebf07c8deb55Tobias Grosser 776e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner // If there isn't a guaranteed-to-execute instruction, we can't promote. 777e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner if (!GuaranteedToExecute) 778e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner return; 779a3574fb7e5b7b4517eb81c8c76f05e5be05eec1bTobias Grosser 780e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner // Otherwise, this is safe to promote, lets do it! 781a3574fb7e5b7b4517eb81c8c76f05e5be05eec1bTobias Grosser DEBUG(dbgs() << "LICM: Promoting value stored to in loop: " <<*SomePtr<<'\n'); 782e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner Changed = true; 783e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner ++NumPromoted; 784bc2265abe1d1b830995bb2f6322409bc7d7c5740Devang Patel 785dda266d4ce34bafed3b213ef0370cd9209159ba5Eli Friedman // Grab a debug location for the inserted loads/stores; given that the 786dda266d4ce34bafed3b213ef0370cd9209159ba5Eli Friedman // inserted loads/stores have little relation to the original loads/stores, 787dda266d4ce34bafed3b213ef0370cd9209159ba5Eli Friedman // this code just arbitrarily picks a location from one, since any debug 788dda266d4ce34bafed3b213ef0370cd9209159ba5Eli Friedman // location is better than none. 789dda266d4ce34bafed3b213ef0370cd9209159ba5Eli Friedman DebugLoc DL = LoopUses[0]->getDebugLoc(); 790dda266d4ce34bafed3b213ef0370cd9209159ba5Eli Friedman 791deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner SmallVector<BasicBlock*, 8> ExitBlocks; 792deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner CurLoop->getUniqueExitBlocks(ExitBlocks); 793a3574fb7e5b7b4517eb81c8c76f05e5be05eec1bTobias Grosser 794e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner // We use the SSAUpdater interface to insert phi nodes as required. 795e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner SmallVector<PHINode*, 16> NewPHIs; 796e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner SSAUpdater SSA(&NewPHIs); 797deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner LoopPromoter Promoter(SomePtr, LoopUses, SSA, PointerMustAliases, ExitBlocks, 798df7102b7d6d472c58d5f0fcc16e0ebf07c8deb55Tobias Grosser *CurAST, DL, Alignment); 799a3574fb7e5b7b4517eb81c8c76f05e5be05eec1bTobias Grosser 800deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner // Set up the preheader to have a definition of the value. It is the live-out 801deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner // value from the preheader that uses in the loop will use. 802deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner LoadInst *PreheaderLoad = 803deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner new LoadInst(SomePtr, SomePtr->getName()+".promoted", 804deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner Preheader->getTerminator()); 805df7102b7d6d472c58d5f0fcc16e0ebf07c8deb55Tobias Grosser PreheaderLoad->setAlignment(Alignment); 806dda266d4ce34bafed3b213ef0370cd9209159ba5Eli Friedman PreheaderLoad->setDebugLoc(DL); 807e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner SSA.AddAvailableValue(Preheader, PreheaderLoad); 808e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner 809deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner // Rewrite all the loads in the loop and remember all the definitions from 810deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner // stores in the loop. 811deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner Promoter.run(LoopUses); 8120e382192c1a7750a157e470f749645ac2266d317Eli Friedman 8130e382192c1a7750a157e470f749645ac2266d317Eli Friedman // If the SSAUpdater didn't use the load in the preheader, just zap it now. 8140e382192c1a7750a157e470f749645ac2266d317Eli Friedman if (PreheaderLoad->use_empty()) 8150e382192c1a7750a157e470f749645ac2266d317Eli Friedman PreheaderLoad->eraseFromParent(); 816f5e84aa0887d3fcd752d4a4fa1bb0e526be49f20Chris Lattner} 81791d22c8b1ec2ad8f2f29804b729473ccf720fb3eDevang Patel 818e488064922f12c4cf07f3aef9a4d2d3ffd15f9c0Chris Lattner 81991d22c8b1ec2ad8f2f29804b729473ccf720fb3eDevang Patel/// cloneBasicBlockAnalysis - Simple Analysis hook. Clone alias set info. 82091d22c8b1ec2ad8f2f29804b729473ccf720fb3eDevang Patelvoid LICM::cloneBasicBlockAnalysis(BasicBlock *From, BasicBlock *To, Loop *L) { 8214282e32712da220fd97177772e22ec1ee7e50af2Chris Lattner AliasSetTracker *AST = LoopToAliasSetMap.lookup(L); 82291d22c8b1ec2ad8f2f29804b729473ccf720fb3eDevang Patel if (!AST) 82391d22c8b1ec2ad8f2f29804b729473ccf720fb3eDevang Patel return; 82491d22c8b1ec2ad8f2f29804b729473ccf720fb3eDevang Patel 82591d22c8b1ec2ad8f2f29804b729473ccf720fb3eDevang Patel AST->copyValue(From, To); 82691d22c8b1ec2ad8f2f29804b729473ccf720fb3eDevang Patel} 82791d22c8b1ec2ad8f2f29804b729473ccf720fb3eDevang Patel 82891d22c8b1ec2ad8f2f29804b729473ccf720fb3eDevang Patel/// deleteAnalysisValue - Simple Analysis hook. Delete value V from alias 82991d22c8b1ec2ad8f2f29804b729473ccf720fb3eDevang Patel/// set. 83091d22c8b1ec2ad8f2f29804b729473ccf720fb3eDevang Patelvoid LICM::deleteAnalysisValue(Value *V, Loop *L) { 8314282e32712da220fd97177772e22ec1ee7e50af2Chris Lattner AliasSetTracker *AST = LoopToAliasSetMap.lookup(L); 83291d22c8b1ec2ad8f2f29804b729473ccf720fb3eDevang Patel if (!AST) 83391d22c8b1ec2ad8f2f29804b729473ccf720fb3eDevang Patel return; 83491d22c8b1ec2ad8f2f29804b729473ccf720fb3eDevang Patel 83591d22c8b1ec2ad8f2f29804b729473ccf720fb3eDevang Patel AST->deleteValue(V); 83691d22c8b1ec2ad8f2f29804b729473ccf720fb3eDevang Patel} 837