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
24 class GetElementPtrInst;
29 //===----------------------------------------------------------------------===//
31 // ConstantPropagation - A worklist driven constant propagation pass
33 FunctionPass *createConstantPropagationPass();
35 //===----------------------------------------------------------------------===//
37 // SCCP - Sparse conditional constant propagation.
39 FunctionPass *createSCCPPass();
41 //===----------------------------------------------------------------------===//
43 // DeadInstElimination - This pass quickly removes trivially dead instructions
44 // without modifying the CFG of the function. It is a BasicBlockPass, so it
45 // runs efficiently when queued next to other BasicBlockPass's.
47 Pass *createDeadInstEliminationPass();
49 //===----------------------------------------------------------------------===//
51 // DeadCodeElimination - This pass is more powerful than DeadInstElimination,
52 // because it is worklist driven that can potentially revisit instructions when
53 // their other instructions become dead, to eliminate chains of dead
56 FunctionPass *createDeadCodeEliminationPass();
58 //===----------------------------------------------------------------------===//
60 // DeadStoreElimination - This pass deletes stores that are post-dominated by
61 // must-aliased stores and are not loaded used between the stores.
63 FunctionPass *createDeadStoreEliminationPass();
65 //===----------------------------------------------------------------------===//
67 // AggressiveDCE - This pass uses the SSA based Aggressive DCE algorithm. This
68 // algorithm assumes instructions are dead until proven otherwise, which makes
69 // it more successful are removing non-obviously dead instructions.
71 FunctionPass *createAggressiveDCEPass();
73 //===----------------------------------------------------------------------===//
75 // ScalarReplAggregates - Break up alloca's of aggregates into multiple allocas
78 FunctionPass *createScalarReplAggregatesPass();
80 //===----------------------------------------------------------------------===//
82 // GCSE - This pass is designed to be a very quick global transformation that
83 // eliminates global common subexpressions from a function. It does this by
84 // examining the SSA value graph of the function, instead of doing slow
85 // bit-vector computations.
87 FunctionPass *createGCSEPass();
89 //===----------------------------------------------------------------------===//
91 // InductionVariableSimplify - Transform induction variables in a program to all
92 // use a single canonical induction variable per loop.
94 FunctionPass *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 FunctionPass *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. It takes an
120 // optional parameter used to consult the target machine whether certain
121 // transformations are profitable.
123 FunctionPass *createLoopStrengthReducePass(const TargetLowering *TLI = NULL);
125 //===----------------------------------------------------------------------===//
127 // LoopUnswitch - This pass is a simple loop unswitching pass.
129 FunctionPass *createLoopUnswitchPass();
131 //===----------------------------------------------------------------------===//
133 // LoopUnroll - This pass is a simple loop unrolling pass.
135 FunctionPass *createLoopUnrollPass();
137 //===----------------------------------------------------------------------===//
139 // PromoteMemoryToRegister - This pass is used to promote memory references to
140 // be register references. A simple example of the transformation performed by
144 // %X = alloca int, uint 1 ret int 42
145 // store int 42, int *%X
149 FunctionPass *createPromoteMemoryToRegisterPass();
150 extern const PassInfo *PromoteMemoryToRegisterID;
152 //===----------------------------------------------------------------------===//
154 // DemoteRegisterToMemoryPass - This pass is used to demote registers to memory
155 // references. In basically undoes the PromoteMemoryToRegister pass to make cfg
158 FunctionPass *createDemoteRegisterToMemoryPass();
159 extern const PassInfo *DemoteRegisterToMemoryID;
161 //===----------------------------------------------------------------------===//
163 // Reassociate - This pass reassociates commutative expressions in an order that
164 // is designed to promote better constant propagation, GCSE, LICM, PRE...
166 // For example: 4 + (x + 5) -> x + (4 + 5)
168 FunctionPass *createReassociatePass();
170 //===----------------------------------------------------------------------===//
172 // CorrelatedExpressionElimination - This pass eliminates correlated
173 // conditions, such as these:
175 // if (X > 2) ; // Known false
179 FunctionPass *createCorrelatedExpressionEliminationPass();
181 //===----------------------------------------------------------------------===//
183 // CondPropagationPass - This pass propagates information about conditional
184 // expressions through the program, allowing it to eliminate conditional
185 // branches in some cases.
187 FunctionPass *createCondPropagationPass();
189 //===----------------------------------------------------------------------===//
191 // TailDuplication - Eliminate unconditional branches through controlled code
192 // duplication, creating simpler CFG structures.
194 FunctionPass *createTailDuplicationPass();
196 //===----------------------------------------------------------------------===//
198 // CFGSimplification - Merge basic blocks, eliminate unreachable blocks,
199 // simplify terminator instructions, etc...
201 FunctionPass *createCFGSimplificationPass();
203 //===----------------------------------------------------------------------===//
205 // BreakCriticalEdges - Break all of the critical edges in the CFG by inserting
206 // a dummy basic block. This pass may be "required" by passes that cannot deal
207 // with critical edges. For this usage, a pass must call:
209 // AU.addRequiredID(BreakCriticalEdgesID);
211 // This pass obviously invalidates the CFG, but can update forward dominator
212 // (set, immediate dominators, tree, and frontier) information.
214 FunctionPass *createBreakCriticalEdgesPass();
215 extern const PassInfo *BreakCriticalEdgesID;
217 //===----------------------------------------------------------------------===//
219 // LoopSimplify - Insert Pre-header blocks into the CFG for every function in
220 // the module. This pass updates dominator information, loop information, and
221 // does not add critical edges to the CFG.
223 // AU.addRequiredID(LoopSimplifyID);
225 FunctionPass *createLoopSimplifyPass();
226 extern const PassInfo *LoopSimplifyID;
228 //===----------------------------------------------------------------------===//
230 // LowerSelect - This pass converts SelectInst instructions into conditional
231 // branch and PHI instructions. If the OnlyFP flag is set to true, then only
232 // floating point select instructions are lowered.
234 FunctionPass *createLowerSelectPass(bool OnlyFP = false);
235 extern const PassInfo *LowerSelectID;
237 //===----------------------------------------------------------------------===//
239 // LowerAllocations - Turn malloc and free instructions into %malloc and %free
242 // AU.addRequiredID(LowerAllocationsID);
244 Pass *createLowerAllocationsPass(bool LowerMallocArgToInteger = false);
245 extern const PassInfo *LowerAllocationsID;
247 //===----------------------------------------------------------------------===//
249 // TailCallElimination - This pass eliminates call instructions to the current
250 // function which occur immediately before return instructions.
252 FunctionPass *createTailCallEliminationPass();
254 //===----------------------------------------------------------------------===//
256 // LowerSwitch - This pass converts SwitchInst instructions into a sequence of
257 // chained binary branch instructions.
259 FunctionPass *createLowerSwitchPass();
260 extern const PassInfo *LowerSwitchID;
262 //===----------------------------------------------------------------------===//
264 // LowerPacked - This pass converts VectorType operations into low-level scalar
267 FunctionPass *createLowerPackedPass();
269 //===----------------------------------------------------------------------===//
271 // LowerInvoke - This pass converts invoke and unwind instructions to use sjlj
272 // exception handling mechanisms. Note that after this pass runs the CFG is not
273 // entirely accurate (exceptional control flow edges are not correct anymore) so
274 // only very simple things should be done after the lowerinvoke pass has run
275 // (like generation of native code). This should *NOT* be used as a general
276 // purpose "my LLVM-to-LLVM pass doesn't support the invoke instruction yet"
279 FunctionPass *createLowerInvokePass(const TargetLowering *TLI = NULL);
280 extern const PassInfo *LowerInvokePassID;
282 //===----------------------------------------------------------------------===//
284 // LowerGCPass - This function returns an instance of the "lowergc" pass, which
285 // lowers garbage collection intrinsics to normal LLVM code.
287 FunctionPass *createLowerGCPass();
289 //===----------------------------------------------------------------------===//
291 // BlockPlacement - This pass reorders basic blocks in order to increase the
292 // number of fall-through conditional branches.
294 FunctionPass *createBlockPlacementPass();
296 //===----------------------------------------------------------------------===//
298 // LCSSA - This pass inserts phi nodes at loop boundaries to simplify other loop
301 FunctionPass *createLCSSAPass();
302 extern const PassInfo *LCSSAID;
304 //===----------------------------------------------------------------------===//
306 // PredicateSimplifier - This pass collapses duplicate variables into one
307 // canonical form, and tries to simplify expressions along the way.
309 FunctionPass *createPredicateSimplifierPass();
311 } // End llvm namespace