Scalar.h revision 198396
1//===-- Scalar.h - Scalar Transformations -----------------------*- 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 header file defines prototypes for accessor functions that expose passes 11// in the Scalar transformations library. 12// 13//===----------------------------------------------------------------------===// 14 15#ifndef LLVM_TRANSFORMS_SCALAR_H 16#define LLVM_TRANSFORMS_SCALAR_H 17 18namespace llvm { 19 20class FunctionPass; 21class Pass; 22class GetElementPtrInst; 23class PassInfo; 24class TerminatorInst; 25class TargetLowering; 26 27//===----------------------------------------------------------------------===// 28// 29// ConstantPropagation - A worklist driven constant propagation pass 30// 31FunctionPass *createConstantPropagationPass(); 32 33//===----------------------------------------------------------------------===// 34// 35// SCCP - Sparse conditional constant propagation. 36// 37FunctionPass *createSCCPPass(); 38 39//===----------------------------------------------------------------------===// 40// 41// DeadInstElimination - This pass quickly removes trivially dead instructions 42// without modifying the CFG of the function. It is a BasicBlockPass, so it 43// runs efficiently when queued next to other BasicBlockPass's. 44// 45Pass *createDeadInstEliminationPass(); 46 47//===----------------------------------------------------------------------===// 48// 49// DeadCodeElimination - This pass is more powerful than DeadInstElimination, 50// because it is worklist driven that can potentially revisit instructions when 51// their other instructions become dead, to eliminate chains of dead 52// computations. 53// 54FunctionPass *createDeadCodeEliminationPass(); 55 56//===----------------------------------------------------------------------===// 57// 58// DeadStoreElimination - This pass deletes stores that are post-dominated by 59// must-aliased stores and are not loaded used between the stores. 60// 61FunctionPass *createDeadStoreEliminationPass(); 62 63//===----------------------------------------------------------------------===// 64// 65// AggressiveDCE - This pass uses the SSA based Aggressive DCE algorithm. This 66// algorithm assumes instructions are dead until proven otherwise, which makes 67// it more successful are removing non-obviously dead instructions. 68// 69FunctionPass *createAggressiveDCEPass(); 70 71//===----------------------------------------------------------------------===// 72// 73// ScalarReplAggregates - Break up alloca's of aggregates into multiple allocas 74// if possible. 75// 76FunctionPass *createScalarReplAggregatesPass(signed Threshold = -1); 77 78//===----------------------------------------------------------------------===// 79// 80// InductionVariableSimplify - Transform induction variables in a program to all 81// use a single canonical induction variable per loop. 82// 83Pass *createIndVarSimplifyPass(); 84 85//===----------------------------------------------------------------------===// 86// 87// InstructionCombining - Combine instructions to form fewer, simple 88// instructions. This pass does not modify the CFG, and has a tendency to make 89// instructions dead, so a subsequent DCE pass is useful. 90// 91// This pass combines things like: 92// %Y = add int 1, %X 93// %Z = add int 1, %Y 94// into: 95// %Z = add int 2, %X 96// 97FunctionPass *createInstructionCombiningPass(); 98 99//===----------------------------------------------------------------------===// 100// 101// LICM - This pass is a loop invariant code motion and memory promotion pass. 102// 103Pass *createLICMPass(); 104 105//===----------------------------------------------------------------------===// 106// 107// LoopStrengthReduce - This pass is strength reduces GEP instructions that use 108// a loop's canonical induction variable as one of their indices. It takes an 109// optional parameter used to consult the target machine whether certain 110// transformations are profitable. 111// 112Pass *createLoopStrengthReducePass(const TargetLowering *TLI = 0); 113 114//===----------------------------------------------------------------------===// 115// 116// LoopUnswitch - This pass is a simple loop unswitching pass. 117// 118Pass *createLoopUnswitchPass(bool OptimizeForSize = false); 119 120//===----------------------------------------------------------------------===// 121// 122// LoopUnroll - This pass is a simple loop unrolling pass. 123// 124Pass *createLoopUnrollPass(); 125 126//===----------------------------------------------------------------------===// 127// 128// LoopRotate - This pass is a simple loop rotating pass. 129// 130Pass *createLoopRotatePass(); 131 132//===----------------------------------------------------------------------===// 133// 134// LoopIndexSplit - This pass divides loop's iteration range by spliting loop 135// such that each individual loop is executed efficiently. 136// 137Pass *createLoopIndexSplitPass(); 138 139//===----------------------------------------------------------------------===// 140// 141// PromoteMemoryToRegister - This pass is used to promote memory references to 142// be register references. A simple example of the transformation performed by 143// this pass is: 144// 145// FROM CODE TO CODE 146// %X = alloca i32, i32 1 ret i32 42 147// store i32 42, i32 *%X 148// %Y = load i32* %X 149// ret i32 %Y 150// 151FunctionPass *createPromoteMemoryToRegisterPass(); 152extern const PassInfo *const PromoteMemoryToRegisterID; 153 154//===----------------------------------------------------------------------===// 155// 156// DemoteRegisterToMemoryPass - This pass is used to demote registers to memory 157// references. In basically undoes the PromoteMemoryToRegister pass to make cfg 158// hacking easier. 159// 160FunctionPass *createDemoteRegisterToMemoryPass(); 161extern const PassInfo *const DemoteRegisterToMemoryID; 162 163//===----------------------------------------------------------------------===// 164// 165// Reassociate - This pass reassociates commutative expressions in an order that 166// is designed to promote better constant propagation, GCSE, LICM, PRE... 167// 168// For example: 4 + (x + 5) -> x + (4 + 5) 169// 170FunctionPass *createReassociatePass(); 171 172//===----------------------------------------------------------------------===// 173// 174// CondPropagationPass - This pass propagates information about conditional 175// expressions through the program, allowing it to eliminate conditional 176// branches in some cases. 177// 178FunctionPass *createCondPropagationPass(); 179 180//===----------------------------------------------------------------------===// 181// 182// TailDuplication - Eliminate unconditional branches through controlled code 183// duplication, creating simpler CFG structures. 184// 185FunctionPass *createTailDuplicationPass(); 186 187//===----------------------------------------------------------------------===// 188// 189// JumpThreading - Thread control through mult-pred/multi-succ blocks where some 190// preds always go to some succ. 191// 192FunctionPass *createJumpThreadingPass(); 193 194//===----------------------------------------------------------------------===// 195// 196// CFGSimplification - Merge basic blocks, eliminate unreachable blocks, 197// simplify terminator instructions, etc... 198// 199FunctionPass *createCFGSimplificationPass(); 200 201//===----------------------------------------------------------------------===// 202// 203// BreakCriticalEdges - Break all of the critical edges in the CFG by inserting 204// a dummy basic block. This pass may be "required" by passes that cannot deal 205// with critical edges. For this usage, a pass must call: 206// 207// AU.addRequiredID(BreakCriticalEdgesID); 208// 209// This pass obviously invalidates the CFG, but can update forward dominator 210// (set, immediate dominators, tree, and frontier) information. 211// 212FunctionPass *createBreakCriticalEdgesPass(); 213extern const PassInfo *const BreakCriticalEdgesID; 214 215//===----------------------------------------------------------------------===// 216// 217// LoopSimplify - Insert Pre-header blocks into the CFG for every function in 218// the module. This pass updates dominator information, loop information, and 219// does not add critical edges to the CFG. 220// 221// AU.addRequiredID(LoopSimplifyID); 222// 223Pass *createLoopSimplifyPass(); 224extern const PassInfo *const LoopSimplifyID; 225 226//===----------------------------------------------------------------------===// 227// 228// LowerAllocations - Turn free instructions into @free calls. 229// 230// AU.addRequiredID(LowerAllocationsID); 231// 232Pass *createLowerAllocationsPass(); 233extern const PassInfo *const LowerAllocationsID; 234 235//===----------------------------------------------------------------------===// 236// 237// TailCallElimination - This pass eliminates call instructions to the current 238// function which occur immediately before return instructions. 239// 240FunctionPass *createTailCallEliminationPass(); 241 242//===----------------------------------------------------------------------===// 243// 244// LowerSwitch - This pass converts SwitchInst instructions into a sequence of 245// chained binary branch instructions. 246// 247FunctionPass *createLowerSwitchPass(); 248extern const PassInfo *const LowerSwitchID; 249 250//===----------------------------------------------------------------------===// 251// 252// LowerInvoke - This pass converts invoke and unwind instructions to use sjlj 253// exception handling mechanisms. Note that after this pass runs the CFG is not 254// entirely accurate (exceptional control flow edges are not correct anymore) so 255// only very simple things should be done after the lowerinvoke pass has run 256// (like generation of native code). This should *NOT* be used as a general 257// purpose "my LLVM-to-LLVM pass doesn't support the invoke instruction yet" 258// lowering pass. 259// 260FunctionPass *createLowerInvokePass(const TargetLowering *TLI = 0); 261extern const PassInfo *const LowerInvokePassID; 262 263//===----------------------------------------------------------------------===// 264// 265// BlockPlacement - This pass reorders basic blocks in order to increase the 266// number of fall-through conditional branches. 267// 268FunctionPass *createBlockPlacementPass(); 269 270//===----------------------------------------------------------------------===// 271// 272// LCSSA - This pass inserts phi nodes at loop boundaries to simplify other loop 273// optimizations. 274// 275Pass *createLCSSAPass(); 276extern const PassInfo *const LCSSAID; 277 278//===----------------------------------------------------------------------===// 279// 280// GVN - This pass performs global value numbering and redundant load 281// elimination cotemporaneously. 282// 283FunctionPass *createGVNPass(); 284 285//===----------------------------------------------------------------------===// 286// 287// MemCpyOpt - This pass performs optimizations related to eliminating memcpy 288// calls and/or combining multiple stores into memset's. 289// 290FunctionPass *createMemCpyOptPass(); 291 292//===----------------------------------------------------------------------===// 293// 294// LoopDeletion - This pass performs DCE of non-infinite loops that it 295// can prove are dead. 296// 297Pass *createLoopDeletionPass(); 298 299//===----------------------------------------------------------------------===// 300// 301/// createSimplifyLibCallsPass - This pass optimizes specific calls to 302/// specific well-known (library) functions. 303FunctionPass *createSimplifyLibCallsPass(); 304 305//===----------------------------------------------------------------------===// 306// 307/// createSimplifyHalfPowrLibCallsPass - This is an experimental pass that 308/// optimizes specific half_pow functions. 309FunctionPass *createSimplifyHalfPowrLibCallsPass(); 310 311//===----------------------------------------------------------------------===// 312// 313// CodeGenPrepare - This pass prepares a function for instruction selection. 314// 315FunctionPass *createCodeGenPreparePass(const TargetLowering *TLI = 0); 316 317//===----------------------------------------------------------------------===// 318// 319// CodeGenLICM - This pass performs late LICM; hoisting constants out of loops. 320// 321Pass *createCodeGenLICMPass(); 322 323//===----------------------------------------------------------------------===// 324// 325// InstructionNamer - Give any unnamed non-void instructions "tmp" names. 326// 327FunctionPass *createInstructionNamerPass(); 328extern const PassInfo *const InstructionNamerID; 329 330//===----------------------------------------------------------------------===// 331// 332// SSI - This pass converts instructions to Static Single Information form 333// on demand. 334// 335FunctionPass *createSSIPass(); 336 337//===----------------------------------------------------------------------===// 338// 339// SSI - This pass converts every non-void instuction to Static Single 340// Information form. 341// 342FunctionPass *createSSIEverythingPass(); 343 344} // End llvm namespace 345 346#endif 347