Scalar.h revision d1d6b5cce260808deeac0227b00f6f81a20b2c6f
1//===-- Scalar.h - Scalar Transformations -----------------------*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file was developed by the LLVM research group and is distributed under 6// the University of Illinois Open Source 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 18#include <cstdlib> 19 20namespace llvm { 21 22class ModulePass; 23class FunctionPass; 24class GetElementPtrInst; 25class PassInfo; 26class TerminatorInst; 27class TargetLowering; 28 29//===----------------------------------------------------------------------===// 30// 31// RaisePointerReferences - Try to eliminate as many pointer arithmetic 32// expressions as possible, by converting expressions to use getelementptr and 33// friends. 34// 35FunctionPass *createRaisePointerReferencesPass(); 36 37//===----------------------------------------------------------------------===// 38// 39// Constant Propagation Pass - A worklist driven constant propagation pass 40// 41FunctionPass *createConstantPropagationPass(); 42 43 44//===----------------------------------------------------------------------===// 45// 46// Sparse Conditional Constant Propagation Pass 47// 48FunctionPass *createSCCPPass(); 49 50 51//===----------------------------------------------------------------------===// 52// 53// DeadInstElimination - This pass quickly removes trivially dead instructions 54// without modifying the CFG of the function. It is a BasicBlockPass, so it 55// runs efficiently when queued next to other BasicBlockPass's. 56// 57FunctionPass *createDeadInstEliminationPass(); 58 59 60//===----------------------------------------------------------------------===// 61// 62// DeadCodeElimination - This pass is more powerful than DeadInstElimination, 63// because it is worklist driven that can potentially revisit instructions when 64// their other instructions become dead, to eliminate chains of dead 65// computations. 66// 67FunctionPass *createDeadCodeEliminationPass(); 68 69//===----------------------------------------------------------------------===// 70// 71// DeadStoreElimination - This pass deletes stores that are post-dominated by 72// must-aliased stores and are not loaded used between the stores. 73// 74FunctionPass *createDeadStoreEliminationPass(); 75 76//===----------------------------------------------------------------------===// 77// 78// AggressiveDCE - This pass uses the SSA based Aggressive DCE algorithm. This 79// algorithm assumes instructions are dead until proven otherwise, which makes 80// it more successful are removing non-obviously dead instructions. 81// 82FunctionPass *createAggressiveDCEPass(); 83 84 85//===----------------------------------------------------------------------===// 86// 87// Scalar Replacement of Aggregates - Break up alloca's of aggregates into 88// multiple allocas if possible. 89// 90FunctionPass *createScalarReplAggregatesPass(); 91 92 93//===----------------------------------------------------------------------===// 94// 95// GCSE - This pass is designed to be a very quick global transformation that 96// eliminates global common subexpressions from a function. It does this by 97// examining the SSA value graph of the function, instead of doing slow 98// bit-vector computations. 99// 100FunctionPass *createGCSEPass(); 101 102 103//===----------------------------------------------------------------------===// 104// 105// InductionVariableSimplify - Transform induction variables in a program to all 106// use a single canonical induction variable per loop. 107// 108FunctionPass *createIndVarSimplifyPass(); 109 110 111//===----------------------------------------------------------------------===// 112// 113// InstructionCombining - Combine instructions to form fewer, simple 114// instructions. This pass does not modify the CFG, and has a tendency to 115// make instructions dead, so a subsequent DCE pass is useful. 116// 117// This pass combines things like: 118// %Y = add int 1, %X 119// %Z = add int 1, %Y 120// into: 121// %Z = add int 2, %X 122// 123FunctionPass *createInstructionCombiningPass(); 124 125 126//===----------------------------------------------------------------------===// 127// 128// LICM - This pass is a loop invariant code motion and memory promotion pass. 129// 130FunctionPass *createLICMPass(); 131 132//===----------------------------------------------------------------------===// 133// 134// LoopStrengthReduce - This pass is strength reduces GEP instructions that use 135// a loop's canonical induction variable as one of their indices. It takes an 136// optional parameter used to consult the target machine whether certain 137// transformations are profitable. 138// 139FunctionPass *createLoopStrengthReducePass(const TargetLowering *TLI = NULL); 140 141//===----------------------------------------------------------------------===// 142// 143// LoopUnswitch - This pass is a simple loop unswitching pass. 144// 145FunctionPass *createLoopUnswitchPass(); 146 147 148//===----------------------------------------------------------------------===// 149// 150// LoopUnroll - This pass is a simple loop unrolling pass. 151// 152FunctionPass *createLoopUnrollPass(); 153 154//===----------------------------------------------------------------------===// 155// 156// This pass is used to promote memory references to be register references. A 157// simple example of the transformation performed by this pass is: 158// 159// FROM CODE TO CODE 160// %X = alloca int, uint 1 ret int 42 161// store int 42, int *%X 162// %Y = load int* %X 163// ret int %Y 164// 165FunctionPass *createPromoteMemoryToRegisterPass(); 166 167//===----------------------------------------------------------------------===// 168// 169// This pass is used to demote registers to memory references . 170// In basically undoes the PromoteMemoryToRegister pass to 171// make cfg hacking easier. 172FunctionPass *createDemoteRegisterToMemoryPass(); 173extern const PassInfo *DemoteRegisterToMemoryID; 174 175//===----------------------------------------------------------------------===// 176// 177// This pass reassociates commutative expressions in an order that is designed 178// to promote better constant propagation, GCSE, LICM, PRE... 179// 180// For example: 4 + (x + 5) -> x + (4 + 5) 181// 182FunctionPass *createReassociatePass(); 183 184//===----------------------------------------------------------------------===// 185// 186// This pass eliminates correlated conditions, such as these: 187// if (X == 0) 188// if (X > 2) ; // Known false 189// else 190// Y = X * Z; // = 0 191// 192FunctionPass *createCorrelatedExpressionEliminationPass(); 193 194 195// createCondPropagationPass - This pass propagates information about 196// conditional expressions through the program, allowing it to eliminate 197// conditional branches in some cases. 198// 199FunctionPass *createCondPropagationPass(); 200 201//===----------------------------------------------------------------------===// 202// 203// TailDuplication - Eliminate unconditional branches through controlled code 204// duplication, creating simpler CFG structures. 205// 206FunctionPass *createTailDuplicationPass(); 207 208 209//===----------------------------------------------------------------------===// 210// 211// CFG Simplification - Merge basic blocks, eliminate unreachable blocks, 212// simplify terminator instructions, etc... 213// 214FunctionPass *createCFGSimplificationPass(); 215 216 217//===----------------------------------------------------------------------===// 218// 219// BreakCriticalEdges pass - Break all of the critical edges in the CFG by 220// inserting a dummy basic block. This pass may be "required" by passes that 221// cannot deal with critical edges. For this usage, a pass must call: 222// 223// AU.addRequiredID(BreakCriticalEdgesID); 224// 225// This pass obviously invalidates the CFG, but can update forward dominator 226// (set, immediate dominators, tree, and frontier) information. 227// 228FunctionPass *createBreakCriticalEdgesPass(); 229extern const PassInfo *BreakCriticalEdgesID; 230 231//===----------------------------------------------------------------------===// 232// 233// LoopSimplify pass - Insert Pre-header blocks into the CFG for every function 234// in the module. This pass updates dominator information, loop information, 235// and does not add critical edges to the CFG. 236// 237// AU.addRequiredID(LoopSimplifyID); 238// 239FunctionPass *createLoopSimplifyPass(); 240extern const PassInfo *LoopSimplifyID; 241 242//===----------------------------------------------------------------------===// 243// 244// This pass eliminates call instructions to the current function which occur 245// immediately before return instructions. 246// 247FunctionPass *createTailCallEliminationPass(); 248 249 250//===----------------------------------------------------------------------===// 251// This pass convert malloc and free instructions to %malloc & %free function 252// calls. 253// 254FunctionPass *createLowerAllocationsPass(bool LowerMallocArgToInteger = false); 255 256//===----------------------------------------------------------------------===// 257// This pass converts SwitchInst instructions into a sequence of chained binary 258// branch instructions. 259// 260FunctionPass *createLowerSwitchPass(); 261 262//===----------------------------------------------------------------------===// 263// This pass converts SelectInst instructions into conditional branch and PHI 264// instructions. If the OnlyFP flag is set to true, then only floating point 265// select instructions are lowered. 266// 267FunctionPass *createLowerSelectPass(bool OnlyFP = false); 268 269//===----------------------------------------------------------------------===// 270// This pass converts PackedType operations into low-level scalar operations. 271// 272FunctionPass *createLowerPackedPass(); 273 274//===----------------------------------------------------------------------===// 275// This pass converts invoke and unwind instructions to use sjlj exception 276// handling mechanisms. Note that after this pass runs the CFG is not entirely 277// accurate (exceptional control flow edges are not correct anymore) so only 278// very simple things should be done after the lowerinvoke pass has run (like 279// generation of native code). This should *NOT* be used as a general purpose 280// "my LLVM-to-LLVM pass doesn't support the invoke instruction yet" lowering 281// pass. 282// 283FunctionPass *createLowerInvokePass(unsigned JumBufSize = 200, 284 unsigned JumpBufAlign = 0); 285extern const PassInfo *LowerInvokePassID; 286 287 288//===----------------------------------------------------------------------===// 289/// createLowerGCPass - This function returns an instance of the "lowergc" 290/// pass, which lowers garbage collection intrinsics to normal LLVM code. 291/// 292FunctionPass *createLowerGCPass(); 293 294//===----------------------------------------------------------------------===// 295// This pass reorders basic blocks in order to increase the number of fall- 296// through conditional branches. 297FunctionPass *createBlockPlacementPass(); 298 299//===----------------------------------------------------------------------===// 300// This pass does partial redundancy elimination. 301FunctionPass *createPREPass(); 302 303} // End llvm namespace 304 305#endif 306