1 //===-- Scalar.h - Scalar Transformations -----------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
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.
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
25 class GetElementPtrInst;
30 //===----------------------------------------------------------------------===//
32 // ConstantPropagation - A worklist driven constant propagation pass
34 FunctionPass *createConstantPropagationPass();
36 //===----------------------------------------------------------------------===//
38 // SCCP - Sparse conditional constant propagation.
40 FunctionPass *createSCCPPass();
42 //===----------------------------------------------------------------------===//
44 // DeadInstElimination - This pass quickly removes trivially dead instructions
45 // without modifying the CFG of the function. It is a BasicBlockPass, so it
46 // runs efficiently when queued next to other BasicBlockPass's.
48 Pass *createDeadInstEliminationPass();
50 //===----------------------------------------------------------------------===//
52 // DeadCodeElimination - This pass is more powerful than DeadInstElimination,
53 // because it is worklist driven that can potentially revisit instructions when
54 // their other instructions become dead, to eliminate chains of dead
57 FunctionPass *createDeadCodeEliminationPass();
59 //===----------------------------------------------------------------------===//
61 // DeadStoreElimination - This pass deletes stores that are post-dominated by
62 // must-aliased stores and are not loaded used between the stores.
64 FunctionPass *createDeadStoreEliminationPass();
66 //===----------------------------------------------------------------------===//
68 // AggressiveDCE - This pass uses the SSA based Aggressive DCE algorithm. This
69 // algorithm assumes instructions are dead until proven otherwise, which makes
70 // it more successful are removing non-obviously dead instructions.
72 FunctionPass *createAggressiveDCEPass();
74 //===----------------------------------------------------------------------===//
76 // ScalarReplAggregates - Break up alloca's of aggregates into multiple allocas
79 FunctionPass *createScalarReplAggregatesPass();
81 //===----------------------------------------------------------------------===//
83 // GCSE - This pass is designed to be a very quick global transformation that
84 // eliminates global common subexpressions from a function. It does this by
85 // examining the SSA value graph of the function, instead of doing slow
86 // bit-vector computations.
88 FunctionPass *createGCSEPass();
90 //===----------------------------------------------------------------------===//
92 // InductionVariableSimplify - Transform induction variables in a program to all
93 // use a single canonical induction variable per loop.
95 LoopPass *createIndVarSimplifyPass();
97 //===----------------------------------------------------------------------===//
99 // InstructionCombining - Combine instructions to form fewer, simple
100 // instructions. This pass does not modify the CFG, and has a tendency to make
101 // instructions dead, so a subsequent DCE pass is useful.
103 // This pass combines things like:
104 // %Y = add int 1, %X
105 // %Z = add int 1, %Y
107 // %Z = add int 2, %X
109 FunctionPass *createInstructionCombiningPass();
111 //===----------------------------------------------------------------------===//
113 // LICM - This pass is a loop invariant code motion and memory promotion pass.
115 LoopPass *createLICMPass();
117 //===----------------------------------------------------------------------===//
119 // LoopStrengthReduce - This pass is strength reduces GEP instructions that use
120 // a loop's canonical induction variable as one of their indices. It takes an
121 // optional parameter used to consult the target machine whether certain
122 // transformations are profitable.
124 LoopPass *createLoopStrengthReducePass(const TargetLowering *TLI = NULL);
126 //===----------------------------------------------------------------------===//
128 // LoopUnswitch - This pass is a simple loop unswitching pass.
130 LoopPass *createLoopUnswitchPass();
132 //===----------------------------------------------------------------------===//
134 // LoopUnroll - This pass is a simple loop unrolling pass.
136 LoopPass *createLoopUnrollPass();
138 //===----------------------------------------------------------------------===//
140 // PromoteMemoryToRegister - This pass is used to promote memory references to
141 // be register references. A simple example of the transformation performed by
145 // %X = alloca int, uint 1 ret int 42
146 // store int 42, int *%X
150 FunctionPass *createPromoteMemoryToRegisterPass();
151 extern const PassInfo *PromoteMemoryToRegisterID;
153 //===----------------------------------------------------------------------===//
155 // DemoteRegisterToMemoryPass - This pass is used to demote registers to memory
156 // references. In basically undoes the PromoteMemoryToRegister pass to make cfg
159 FunctionPass *createDemoteRegisterToMemoryPass();
160 extern const PassInfo *DemoteRegisterToMemoryID;
162 //===----------------------------------------------------------------------===//
164 // Reassociate - This pass reassociates commutative expressions in an order that
165 // is designed to promote better constant propagation, GCSE, LICM, PRE...
167 // For example: 4 + (x + 5) -> x + (4 + 5)
169 FunctionPass *createReassociatePass();
171 //===----------------------------------------------------------------------===//
173 // CorrelatedExpressionElimination - This pass eliminates correlated
174 // conditions, such as these:
176 // if (X > 2) ; // Known false
180 FunctionPass *createCorrelatedExpressionEliminationPass();
182 //===----------------------------------------------------------------------===//
184 // CondPropagationPass - This pass propagates information about conditional
185 // expressions through the program, allowing it to eliminate conditional
186 // branches in some cases.
188 FunctionPass *createCondPropagationPass();
190 //===----------------------------------------------------------------------===//
192 // TailDuplication - Eliminate unconditional branches through controlled code
193 // duplication, creating simpler CFG structures.
195 FunctionPass *createTailDuplicationPass();
197 //===----------------------------------------------------------------------===//
199 // CFGSimplification - Merge basic blocks, eliminate unreachable blocks,
200 // simplify terminator instructions, etc...
202 FunctionPass *createCFGSimplificationPass();
204 //===----------------------------------------------------------------------===//
206 // BreakCriticalEdges - Break all of the critical edges in the CFG by inserting
207 // a dummy basic block. This pass may be "required" by passes that cannot deal
208 // with critical edges. For this usage, a pass must call:
210 // AU.addRequiredID(BreakCriticalEdgesID);
212 // This pass obviously invalidates the CFG, but can update forward dominator
213 // (set, immediate dominators, tree, and frontier) information.
215 FunctionPass *createBreakCriticalEdgesPass();
216 extern const PassInfo *BreakCriticalEdgesID;
218 //===----------------------------------------------------------------------===//
220 // LoopSimplify - Insert Pre-header blocks into the CFG for every function in
221 // the module. This pass updates dominator information, loop information, and
222 // does not add critical edges to the CFG.
224 // AU.addRequiredID(LoopSimplifyID);
226 FunctionPass *createLoopSimplifyPass();
227 extern const PassInfo *LoopSimplifyID;
229 //===----------------------------------------------------------------------===//
231 // LowerSelect - This pass converts SelectInst instructions into conditional
232 // branch and PHI instructions. If the OnlyFP flag is set to true, then only
233 // floating point select instructions are lowered.
235 FunctionPass *createLowerSelectPass(bool OnlyFP = false);
236 extern const PassInfo *LowerSelectID;
238 //===----------------------------------------------------------------------===//
240 // LowerAllocations - Turn malloc and free instructions into %malloc and %free
243 // AU.addRequiredID(LowerAllocationsID);
245 Pass *createLowerAllocationsPass(bool LowerMallocArgToInteger = false);
246 extern const PassInfo *LowerAllocationsID;
248 //===----------------------------------------------------------------------===//
250 // TailCallElimination - This pass eliminates call instructions to the current
251 // function which occur immediately before return instructions.
253 FunctionPass *createTailCallEliminationPass();
255 //===----------------------------------------------------------------------===//
257 // LowerSwitch - This pass converts SwitchInst instructions into a sequence of
258 // chained binary branch instructions.
260 FunctionPass *createLowerSwitchPass();
261 extern const PassInfo *LowerSwitchID;
263 //===----------------------------------------------------------------------===//
265 // LowerPacked - This pass converts VectorType operations into low-level scalar
268 FunctionPass *createLowerPackedPass();
270 //===----------------------------------------------------------------------===//
272 // LowerInvoke - This pass converts invoke and unwind instructions to use sjlj
273 // exception handling mechanisms. Note that after this pass runs the CFG is not
274 // entirely accurate (exceptional control flow edges are not correct anymore) so
275 // only very simple things should be done after the lowerinvoke pass has run
276 // (like generation of native code). This should *NOT* be used as a general
277 // purpose "my LLVM-to-LLVM pass doesn't support the invoke instruction yet"
280 FunctionPass *createLowerInvokePass(const TargetLowering *TLI = NULL);
281 extern const PassInfo *LowerInvokePassID;
283 //===----------------------------------------------------------------------===//
285 // LowerGCPass - This function returns an instance of the "lowergc" pass, which
286 // lowers garbage collection intrinsics to normal LLVM code.
288 FunctionPass *createLowerGCPass();
290 //===----------------------------------------------------------------------===//
292 // BlockPlacement - This pass reorders basic blocks in order to increase the
293 // number of fall-through conditional branches.
295 FunctionPass *createBlockPlacementPass();
297 //===----------------------------------------------------------------------===//
299 // LCSSA - This pass inserts phi nodes at loop boundaries to simplify other loop
302 FunctionPass *createLCSSAPass();
303 extern const PassInfo *LCSSAID;
305 //===----------------------------------------------------------------------===//
307 // PredicateSimplifier - This pass collapses duplicate variables into one
308 // canonical form, and tries to simplify expressions along the way.
310 FunctionPass *createPredicateSimplifierPass();
312 } // End llvm namespace