1 //===-- Scalar.h - Scalar Transformations -----------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This header file defines prototypes for accessor functions that expose passes
11 // in the Scalar transformations library.
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_TRANSFORMS_SCALAR_H
16 #define LLVM_TRANSFORMS_SCALAR_H
22 class GetElementPtrInst;
28 //===----------------------------------------------------------------------===//
30 // ConstantPropagation - A worklist driven constant propagation pass
32 FunctionPass *createConstantPropagationPass();
34 //===----------------------------------------------------------------------===//
36 // SCCP - Sparse conditional constant propagation.
38 FunctionPass *createSCCPPass();
40 //===----------------------------------------------------------------------===//
42 // DeadInstElimination - This pass quickly removes trivially dead instructions
43 // without modifying the CFG of the function. It is a BasicBlockPass, so it
44 // runs efficiently when queued next to other BasicBlockPass's.
46 Pass *createDeadInstEliminationPass();
48 //===----------------------------------------------------------------------===//
50 // DeadCodeElimination - This pass is more powerful than DeadInstElimination,
51 // because it is worklist driven that can potentially revisit instructions when
52 // their other instructions become dead, to eliminate chains of dead
55 FunctionPass *createDeadCodeEliminationPass();
57 //===----------------------------------------------------------------------===//
59 // DeadStoreElimination - This pass deletes stores that are post-dominated by
60 // must-aliased stores and are not loaded used between the stores.
62 FunctionPass *createDeadStoreEliminationPass();
64 //===----------------------------------------------------------------------===//
66 // AggressiveDCE - This pass uses the SSA based Aggressive DCE algorithm. This
67 // algorithm assumes instructions are dead until proven otherwise, which makes
68 // it more successful are removing non-obviously dead instructions.
70 FunctionPass *createAggressiveDCEPass();
72 //===----------------------------------------------------------------------===//
74 // SROA - Replace aggregates or pieces of aggregates with scalar SSA values.
76 FunctionPass *createSROAPass(bool RequiresDomTree = true);
78 //===----------------------------------------------------------------------===//
80 // ScalarReplAggregates - Break up alloca's of aggregates into multiple allocas
83 FunctionPass *createScalarReplAggregatesPass(signed Threshold = -1,
84 bool UseDomTree = true,
85 signed StructMemberThreshold = -1,
86 signed ArrayElementThreshold = -1,
87 signed ScalarLoadThreshold = -1);
89 //===----------------------------------------------------------------------===//
91 // InductionVariableSimplify - Transform induction variables in a program to all
92 // use a single canonical induction variable per loop.
94 Pass *createIndVarSimplifyPass();
96 //===----------------------------------------------------------------------===//
98 // InstructionCombining - Combine instructions to form fewer, simple
99 // instructions. This pass does not modify the CFG, and has a tendency to make
100 // instructions dead, so a subsequent DCE pass is useful.
102 // This pass combines things like:
103 // %Y = add int 1, %X
104 // %Z = add int 1, %Y
106 // %Z = add int 2, %X
108 FunctionPass *createInstructionCombiningPass();
110 //===----------------------------------------------------------------------===//
112 // LICM - This pass is a loop invariant code motion and memory promotion pass.
114 Pass *createLICMPass();
116 //===----------------------------------------------------------------------===//
118 // LoopStrengthReduce - This pass is strength reduces GEP instructions that use
119 // a loop's canonical induction variable as one of their indices.
121 Pass *createLoopStrengthReducePass();
123 Pass *createGlobalMergePass(const TargetMachine *TM = 0);
125 //===----------------------------------------------------------------------===//
127 // LoopUnswitch - This pass is a simple loop unswitching pass.
129 Pass *createLoopUnswitchPass(bool OptimizeForSize = false);
131 //===----------------------------------------------------------------------===//
133 // LoopInstSimplify - This pass simplifies instructions in a loop's body.
135 Pass *createLoopInstSimplifyPass();
137 //===----------------------------------------------------------------------===//
139 // LoopUnroll - This pass is a simple loop unrolling pass.
141 Pass *createLoopUnrollPass(int Threshold = -1, int Count = -1, int AllowPartial = -1);
143 //===----------------------------------------------------------------------===//
145 // LoopRotate - This pass is a simple loop rotating pass.
147 Pass *createLoopRotatePass();
149 //===----------------------------------------------------------------------===//
151 // LoopIdiom - This pass recognizes and replaces idioms in loops.
153 Pass *createLoopIdiomPass();
155 //===----------------------------------------------------------------------===//
157 // PromoteMemoryToRegister - This pass is used to promote memory references to
158 // be register references. A simple example of the transformation performed by
162 // %X = alloca i32, i32 1 ret i32 42
163 // store i32 42, i32 *%X
167 FunctionPass *createPromoteMemoryToRegisterPass();
169 //===----------------------------------------------------------------------===//
171 // DemoteRegisterToMemoryPass - This pass is used to demote registers to memory
172 // references. In basically undoes the PromoteMemoryToRegister pass to make cfg
175 FunctionPass *createDemoteRegisterToMemoryPass();
176 extern char &DemoteRegisterToMemoryID;
178 //===----------------------------------------------------------------------===//
180 // Reassociate - This pass reassociates commutative expressions in an order that
181 // is designed to promote better constant propagation, GCSE, LICM, PRE...
183 // For example: 4 + (x + 5) -> x + (4 + 5)
185 FunctionPass *createReassociatePass();
187 //===----------------------------------------------------------------------===//
189 // JumpThreading - Thread control through mult-pred/multi-succ blocks where some
190 // preds always go to some succ.
192 FunctionPass *createJumpThreadingPass();
194 //===----------------------------------------------------------------------===//
196 // CFGSimplification - Merge basic blocks, eliminate unreachable blocks,
197 // simplify terminator instructions, etc...
199 FunctionPass *createCFGSimplificationPass();
201 //===----------------------------------------------------------------------===//
203 // CFG Structurization - Remove irreducible control flow
205 Pass *createStructurizeCFGPass();
207 //===----------------------------------------------------------------------===//
209 // BreakCriticalEdges - Break all of the critical edges in the CFG by inserting
210 // a dummy basic block. This pass may be "required" by passes that cannot deal
211 // with critical edges. For this usage, a pass must call:
213 // AU.addRequiredID(BreakCriticalEdgesID);
215 // This pass obviously invalidates the CFG, but can update forward dominator
216 // (set, immediate dominators, tree, and frontier) information.
218 FunctionPass *createBreakCriticalEdgesPass();
219 extern char &BreakCriticalEdgesID;
221 //===----------------------------------------------------------------------===//
223 // LoopSimplify - Insert Pre-header blocks into the CFG for every function in
224 // the module. This pass updates dominator information, loop information, and
225 // does not add critical edges to the CFG.
227 // AU.addRequiredID(LoopSimplifyID);
229 Pass *createLoopSimplifyPass();
230 extern char &LoopSimplifyID;
232 //===----------------------------------------------------------------------===//
234 // TailCallElimination - This pass eliminates call instructions to the current
235 // function which occur immediately before return instructions.
237 FunctionPass *createTailCallEliminationPass();
239 //===----------------------------------------------------------------------===//
241 // LowerSwitch - This pass converts SwitchInst instructions into a sequence of
242 // chained binary branch instructions.
244 FunctionPass *createLowerSwitchPass();
245 extern char &LowerSwitchID;
247 //===----------------------------------------------------------------------===//
249 // LowerInvoke - This pass converts invoke and unwind instructions to use sjlj
250 // exception handling mechanisms. Note that after this pass runs the CFG is not
251 // entirely accurate (exceptional control flow edges are not correct anymore) so
252 // only very simple things should be done after the lowerinvoke pass has run
253 // (like generation of native code). This should *NOT* be used as a general
254 // purpose "my LLVM-to-LLVM pass doesn't support the invoke instruction yet"
257 FunctionPass *createLowerInvokePass(const TargetMachine *TM = 0,
258 bool useExpensiveEHSupport = false);
259 extern char &LowerInvokePassID;
261 //===----------------------------------------------------------------------===//
263 // BlockPlacement - This pass reorders basic blocks in order to increase the
264 // number of fall-through conditional branches.
266 FunctionPass *createBlockPlacementPass();
268 //===----------------------------------------------------------------------===//
270 // LCSSA - This pass inserts phi nodes at loop boundaries to simplify other loop
273 Pass *createLCSSAPass();
274 extern char &LCSSAID;
276 //===----------------------------------------------------------------------===//
278 // EarlyCSE - This pass performs a simple and fast CSE pass over the dominator
281 FunctionPass *createEarlyCSEPass();
283 //===----------------------------------------------------------------------===//
285 // GVN - This pass performs global value numbering and redundant load
286 // elimination cotemporaneously.
288 FunctionPass *createGVNPass(bool NoLoads = false);
290 //===----------------------------------------------------------------------===//
292 // MemCpyOpt - This pass performs optimizations related to eliminating memcpy
293 // calls and/or combining multiple stores into memset's.
295 FunctionPass *createMemCpyOptPass();
297 //===----------------------------------------------------------------------===//
299 // LoopDeletion - This pass performs DCE of non-infinite loops that it
300 // can prove are dead.
302 Pass *createLoopDeletionPass();
304 //===----------------------------------------------------------------------===//
306 // CodeGenPrepare - This pass prepares a function for instruction selection.
308 FunctionPass *createCodeGenPreparePass(const TargetMachine *TM = 0);
310 //===----------------------------------------------------------------------===//
312 // InstructionNamer - Give any unnamed non-void instructions "tmp" names.
314 FunctionPass *createInstructionNamerPass();
315 extern char &InstructionNamerID;
317 //===----------------------------------------------------------------------===//
319 // Sink - Code Sinking
321 FunctionPass *createSinkingPass();
323 //===----------------------------------------------------------------------===//
325 // LowerAtomic - Lower atomic intrinsics to non-atomic form
327 Pass *createLowerAtomicPass();
329 //===----------------------------------------------------------------------===//
331 // ValuePropagation - Propagate CFG-derived value information
333 Pass *createCorrelatedValuePropagationPass();
335 //===----------------------------------------------------------------------===//
337 // InstructionSimplifier - Remove redundant instructions.
339 FunctionPass *createInstructionSimplifierPass();
340 extern char &InstructionSimplifierID;
343 //===----------------------------------------------------------------------===//
345 // LowerExpectIntrinsics - Removes llvm.expect intrinsics and creates
346 // "block_weights" metadata.
347 FunctionPass *createLowerExpectIntrinsicPass();
350 } // End llvm namespace