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Scalar.h

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00001 //===-- Scalar.h - Scalar Transformations -----------------------*- C++ -*-===//
00002 // 
00003 //                     The LLVM Compiler Infrastructure
00004 //
00005 // This file was developed by the LLVM research group and is distributed under
00006 // the University of Illinois Open Source License. See LICENSE.TXT for details.
00007 // 
00008 //===----------------------------------------------------------------------===//
00009 //
00010 // This header file defines prototypes for accessor functions that expose passes
00011 // in the Scalar transformations library.
00012 //
00013 //===----------------------------------------------------------------------===//
00014 
00015 #ifndef LLVM_TRANSFORMS_SCALAR_H
00016 #define LLVM_TRANSFORMS_SCALAR_H
00017 
00018 namespace llvm {
00019 
00020 class ModulePass;
00021 class FunctionPass;
00022 class GetElementPtrInst;
00023 class PassInfo;
00024 class TerminatorInst;
00025 
00026 //===----------------------------------------------------------------------===//
00027 //
00028 // RaisePointerReferences - Try to eliminate as many pointer arithmetic
00029 // expressions as possible, by converting expressions to use getelementptr and
00030 // friends.
00031 //
00032 FunctionPass *createRaisePointerReferencesPass();
00033 
00034 //===----------------------------------------------------------------------===//
00035 //
00036 // Constant Propagation Pass - A worklist driven constant propagation pass
00037 //
00038 FunctionPass *createConstantPropagationPass();
00039 
00040 
00041 //===----------------------------------------------------------------------===//
00042 //
00043 // Sparse Conditional Constant Propagation Pass
00044 //
00045 FunctionPass *createSCCPPass();
00046 
00047 
00048 //===----------------------------------------------------------------------===//
00049 //
00050 // DeadInstElimination - This pass quickly removes trivially dead instructions
00051 // without modifying the CFG of the function.  It is a BasicBlockPass, so it
00052 // runs efficiently when queued next to other BasicBlockPass's.
00053 //
00054 FunctionPass *createDeadInstEliminationPass();
00055 
00056 
00057 //===----------------------------------------------------------------------===//
00058 //
00059 // DeadCodeElimination - This pass is more powerful than DeadInstElimination,
00060 // because it is worklist driven that can potentially revisit instructions when
00061 // their other instructions become dead, to eliminate chains of dead
00062 // computations.
00063 //
00064 FunctionPass *createDeadCodeEliminationPass();
00065 
00066 //===----------------------------------------------------------------------===//
00067 //
00068 // DeadStoreElimination - This pass deletes stores that are post-dominated by
00069 // must-aliased stores and are not loaded used between the stores.
00070 //
00071 FunctionPass *createDeadStoreEliminationPass();
00072 
00073 //===----------------------------------------------------------------------===//
00074 //
00075 // AggressiveDCE - This pass uses the SSA based Aggressive DCE algorithm.  This
00076 // algorithm assumes instructions are dead until proven otherwise, which makes
00077 // it more successful are removing non-obviously dead instructions.
00078 //
00079 FunctionPass *createAggressiveDCEPass();
00080 
00081 
00082 //===----------------------------------------------------------------------===//
00083 //
00084 // Scalar Replacement of Aggregates - Break up alloca's of aggregates into
00085 // multiple allocas if possible.
00086 //
00087 FunctionPass *createScalarReplAggregatesPass();
00088 
00089 
00090 //===----------------------------------------------------------------------===//
00091 //
00092 // GCSE - This pass is designed to be a very quick global transformation that
00093 // eliminates global common subexpressions from a function.  It does this by
00094 // examining the SSA value graph of the function, instead of doing slow
00095 // bit-vector computations.
00096 //
00097 FunctionPass *createGCSEPass();
00098 
00099 
00100 //===----------------------------------------------------------------------===//
00101 //
00102 // InductionVariableSimplify - Transform induction variables in a program to all
00103 // use a single canonical induction variable per loop.
00104 //
00105 FunctionPass *createIndVarSimplifyPass();
00106 
00107 
00108 //===----------------------------------------------------------------------===//
00109 //
00110 // InstructionCombining - Combine instructions to form fewer, simple
00111 //   instructions.  This pass does not modify the CFG, and has a tendency to
00112 //   make instructions dead, so a subsequent DCE pass is useful.
00113 //
00114 // This pass combines things like:
00115 //    %Y = add int 1, %X
00116 //    %Z = add int 1, %Y
00117 // into:
00118 //    %Z = add int 2, %X
00119 //
00120 FunctionPass *createInstructionCombiningPass();
00121 
00122 
00123 //===----------------------------------------------------------------------===//
00124 //
00125 // LICM - This pass is a loop invariant code motion and memory promotion pass.
00126 //
00127 FunctionPass *createLICMPass();
00128 
00129 //===----------------------------------------------------------------------===//
00130 //
00131 // LoopStrengthReduce - This pass is strength reduces GEP instructions that use
00132 // a loop's canonical induction variable as one of their indices.
00133 //
00134 FunctionPass *createLoopStrengthReducePass();
00135 
00136 //===----------------------------------------------------------------------===//
00137 //
00138 // LoopUnswitch - This pass is a simple loop unswitching pass.
00139 //
00140 FunctionPass *createLoopUnswitchPass();
00141 
00142 
00143 //===----------------------------------------------------------------------===//
00144 //
00145 // LoopUnroll - This pass is a simple loop unrolling pass.
00146 //
00147 FunctionPass *createLoopUnrollPass();
00148 
00149 //===----------------------------------------------------------------------===//
00150 //
00151 // This pass is used to promote memory references to be register references.  A
00152 // simple example of the transformation performed by this pass is:
00153 //
00154 //        FROM CODE                           TO CODE
00155 //   %X = alloca int, uint 1                 ret int 42
00156 //   store int 42, int *%X
00157 //   %Y = load int* %X
00158 //   ret int %Y
00159 //
00160 FunctionPass *createPromoteMemoryToRegister();
00161 
00162 
00163 //===----------------------------------------------------------------------===//
00164 //
00165 // This pass reassociates commutative expressions in an order that is designed
00166 // to promote better constant propagation, GCSE, LICM, PRE...
00167 //
00168 // For example:  4 + (x + 5)  ->  x + (4 + 5)
00169 //
00170 FunctionPass *createReassociatePass();
00171 
00172 //===----------------------------------------------------------------------===//
00173 //
00174 // This pass eliminates correlated conditions, such as these:
00175 //  if (X == 0)
00176 //    if (X > 2) ;   // Known false
00177 //    else
00178 //      Y = X * Z;   // = 0
00179 //
00180 FunctionPass *createCorrelatedExpressionEliminationPass();
00181 
00182 //===----------------------------------------------------------------------===//
00183 //
00184 // TailDuplication - Eliminate unconditional branches through controlled code
00185 // duplication, creating simpler CFG structures.
00186 //
00187 FunctionPass *createTailDuplicationPass();
00188 
00189 
00190 //===----------------------------------------------------------------------===//
00191 //
00192 // CFG Simplification - Merge basic blocks, eliminate unreachable blocks,
00193 // simplify terminator instructions, etc...
00194 //
00195 FunctionPass *createCFGSimplificationPass();
00196 
00197 
00198 //===----------------------------------------------------------------------===//
00199 //
00200 // BreakCriticalEdges pass - Break all of the critical edges in the CFG by
00201 // inserting a dummy basic block.  This pass may be "required" by passes that
00202 // cannot deal with critical edges.  For this usage, a pass must call:
00203 //
00204 //   AU.addRequiredID(BreakCriticalEdgesID);
00205 //
00206 // This pass obviously invalidates the CFG, but can update forward dominator
00207 // (set, immediate dominators, tree, and frontier) information.
00208 //
00209 FunctionPass *createBreakCriticalEdgesPass();
00210 extern const PassInfo *BreakCriticalEdgesID;
00211 
00212 //===----------------------------------------------------------------------===//
00213 //
00214 // LoopSimplify pass - Insert Pre-header blocks into the CFG for every function
00215 // in the module.  This pass updates dominator information, loop information,
00216 // and does not add critical edges to the CFG.
00217 //
00218 //   AU.addRequiredID(LoopSimplifyID);
00219 //
00220 FunctionPass *createLoopSimplifyPass();
00221 extern const PassInfo *LoopSimplifyID;
00222 
00223 //===----------------------------------------------------------------------===//
00224 // 
00225 // This pass eliminates call instructions to the current function which occur
00226 // immediately before return instructions.
00227 //
00228 FunctionPass *createTailCallEliminationPass();
00229 
00230 
00231 //===----------------------------------------------------------------------===//
00232 // This pass convert malloc and free instructions to %malloc & %free function
00233 // calls.
00234 //
00235 FunctionPass *createLowerAllocationsPass();
00236 
00237 //===----------------------------------------------------------------------===//
00238 // This pass converts SwitchInst instructions into a sequence of chained binary
00239 // branch instructions.
00240 //
00241 FunctionPass *createLowerSwitchPass();
00242 
00243 //===----------------------------------------------------------------------===//
00244 // This pass converts SelectInst instructions into conditional branch and PHI
00245 // instructions.  If the OnlyFP flag is set to true, then only floating point
00246 // select instructions are lowered.
00247 //
00248 FunctionPass *createLowerSelectPass(bool OnlyFP = false);
00249 
00250 //===----------------------------------------------------------------------===//
00251 // This pass converts PackedType operations into low-level scalar operations.
00252 //
00253 FunctionPass *createLowerPackedPass();
00254 
00255 //===----------------------------------------------------------------------===//
00256 // This pass converts invoke and unwind instructions to use sjlj exception
00257 // handling mechanisms.  Note that after this pass runs the CFG is not entirely
00258 // accurate (exceptional control flow edges are not correct anymore) so only
00259 // very simple things should be done after the lowerinvoke pass has run (like
00260 // generation of native code).  This should *NOT* be used as a general purpose
00261 // "my LLVM-to-LLVM pass doesn't support the invoke instruction yet" lowering
00262 // pass.
00263 //
00264 FunctionPass *createLowerInvokePass();
00265 extern const PassInfo *LowerInvokePassID;
00266 
00267   
00268 //===----------------------------------------------------------------------===//
00269 /// createLowerGCPass - This function returns an instance of the "lowergc"
00270 /// pass, which lowers garbage collection intrinsics to normal LLVM code.
00271 ///
00272 FunctionPass *createLowerGCPass();
00273 
00274 //===----------------------------------------------------------------------===//
00275 // Returns a pass which converts all instances of ConstantExpression
00276 // into regular LLVM instructions.
00277 FunctionPass* createLowerConstantExpressionsPass();
00278   
00279 } // End llvm namespace
00280 
00281 #endif