| //===-- Scalar.h - Scalar Transformations -----------------------*- C++ -*-===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file was developed by the LLVM research group and is distributed under |
| // the University of Illinois Open Source License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This header file defines prototypes for accessor functions that expose passes |
| // in the Scalar transformations library. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_TRANSFORMS_SCALAR_H |
| #define LLVM_TRANSFORMS_SCALAR_H |
| |
| class Pass; |
| class FunctionPass; |
| class GetElementPtrInst; |
| class PassInfo; |
| class TerminatorInst; |
| |
| //===----------------------------------------------------------------------===// |
| // |
| // RaisePointerReferences - Try to eliminate as many pointer arithmetic |
| // expressions as possible, by converting expressions to use getelementptr and |
| // friends. |
| // |
| Pass *createRaisePointerReferencesPass(); |
| |
| //===----------------------------------------------------------------------===// |
| // |
| // Constant Propagation Pass - A worklist driven constant propagation pass |
| // |
| Pass *createConstantPropagationPass(); |
| |
| |
| //===----------------------------------------------------------------------===// |
| // |
| // Sparse Conditional Constant Propagation Pass |
| // |
| Pass *createSCCPPass(); |
| |
| |
| //===----------------------------------------------------------------------===// |
| // |
| // DeadInstElimination - This pass quickly removes trivially dead instructions |
| // without modifying the CFG of the function. It is a BasicBlockPass, so it |
| // runs efficiently when queued next to other BasicBlockPass's. |
| // |
| Pass *createDeadInstEliminationPass(); |
| |
| |
| //===----------------------------------------------------------------------===// |
| // |
| // DeadCodeElimination - This pass is more powerful than DeadInstElimination, |
| // because it is worklist driven that can potentially revisit instructions when |
| // their other instructions become dead, to eliminate chains of dead |
| // computations. |
| // |
| Pass *createDeadCodeEliminationPass(); |
| |
| |
| //===----------------------------------------------------------------------===// |
| // |
| // AggressiveDCE - This pass uses the SSA based Aggressive DCE algorithm. This |
| // algorithm assumes instructions are dead until proven otherwise, which makes |
| // it more successful are removing non-obviously dead instructions. |
| // |
| Pass *createAggressiveDCEPass(); |
| |
| |
| //===----------------------------------------------------------------------===// |
| // |
| // Scalar Replacement of Aggregates - Break up alloca's of aggregates into |
| // multiple allocas if possible. |
| // |
| Pass *createScalarReplAggregatesPass(); |
| |
| //===----------------------------------------------------------------------===// |
| // |
| // DecomposeMultiDimRefs - Convert multi-dimensional references consisting of |
| // any combination of 2 or more array and structure indices into a sequence of |
| // instructions (using getelementpr and cast) so that each instruction has at |
| // most one index (except structure references, which need an extra leading |
| // index of [0]). |
| |
| // This pass decomposes all multi-dimensional references in a function. |
| FunctionPass *createDecomposeMultiDimRefsPass(); |
| |
| // This function decomposes a single instance of such a reference. |
| // Return value: true if the instruction was replaced; false otherwise. |
| // |
| bool DecomposeArrayRef(GetElementPtrInst* GEP); |
| |
| //===----------------------------------------------------------------------===// |
| // |
| // GCSE - This pass is designed to be a very quick global transformation that |
| // eliminates global common subexpressions from a function. It does this by |
| // examining the SSA value graph of the function, instead of doing slow |
| // bit-vector computations. |
| // |
| Pass *createGCSEPass(); |
| |
| |
| //===----------------------------------------------------------------------===// |
| // |
| // InductionVariableSimplify - Transform induction variables in a program to all |
| // use a single canonical induction variable per loop. |
| // |
| Pass *createIndVarSimplifyPass(); |
| |
| |
| //===----------------------------------------------------------------------===// |
| // |
| // InstructionCombining - Combine instructions to form fewer, simple |
| // instructions. This pass does not modify the CFG, and has a tendancy to |
| // make instructions dead, so a subsequent DCE pass is useful. |
| // |
| // This pass combines things like: |
| // %Y = add int 1, %X |
| // %Z = add int 1, %Y |
| // into: |
| // %Z = add int 2, %X |
| // |
| Pass *createInstructionCombiningPass(); |
| |
| |
| //===----------------------------------------------------------------------===// |
| // |
| // LICM - This pass is a simple natural loop based loop invariant code motion |
| // pass. |
| // |
| Pass *createLICMPass(); |
| |
| |
| //===----------------------------------------------------------------------===// |
| // |
| // PiNodeInsertion - This pass inserts single entry Phi nodes into basic blocks |
| // that are preceeded by a conditional branch, where the branch gives |
| // information about the operands of the condition. For example, this C code: |
| // if (x == 0) { ... = x + 4; |
| // becomes: |
| // if (x == 0) { |
| // x2 = phi(x); // Node that can hold data flow information about X |
| // ... = x2 + 4; |
| // |
| // Since the direction of the condition branch gives information about X itself |
| // (whether or not it is zero), some passes (like value numbering or ABCD) can |
| // use the inserted Phi/Pi nodes as a place to attach information, in this case |
| // saying that X has a value of 0 in this scope. The power of this analysis |
| // information is that "in the scope" translates to "for all uses of x2". |
| // |
| // This special form of Phi node is refered to as a Pi node, following the |
| // terminology defined in the "Array Bounds Checks on Demand" paper. |
| // |
| Pass *createPiNodeInsertionPass(); |
| |
| |
| //===----------------------------------------------------------------------===// |
| // |
| // This pass is used to promote memory references to be register references. A |
| // simple example of the transformation performed by this pass is: |
| // |
| // FROM CODE TO CODE |
| // %X = alloca int, uint 1 ret int 42 |
| // store int 42, int *%X |
| // %Y = load int* %X |
| // ret int %Y |
| // |
| Pass *createPromoteMemoryToRegister(); |
| |
| |
| //===----------------------------------------------------------------------===// |
| // |
| // This pass reassociates commutative expressions in an order that is designed |
| // to promote better constant propagation, GCSE, LICM, PRE... |
| // |
| // For example: 4 + (x + 5) -> x + (4 + 5) |
| // |
| Pass *createReassociatePass(); |
| |
| //===----------------------------------------------------------------------===// |
| // |
| // This pass eliminates correlated conditions, such as these: |
| // if (X == 0) |
| // if (X > 2) ; // Known false |
| // else |
| // Y = X * Z; // = 0 |
| // |
| Pass *createCorrelatedExpressionEliminationPass(); |
| |
| //===----------------------------------------------------------------------===// |
| // |
| // TailDuplication - Eliminate unconditional branches through controlled code |
| // duplication, creating simpler CFG structures. |
| // |
| Pass *createTailDuplicationPass(); |
| |
| |
| //===----------------------------------------------------------------------===// |
| // |
| // CFG Simplification - Merge basic blocks, eliminate unreachable blocks, |
| // simplify terminator instructions, etc... |
| // |
| FunctionPass *createCFGSimplificationPass(); |
| |
| |
| //===----------------------------------------------------------------------===// |
| // |
| // BreakCriticalEdges pass - Break all of the critical edges in the CFG by |
| // inserting a dummy basic block. This pass may be "required" by passes that |
| // cannot deal with critical edges. For this usage, a pass must call: |
| // |
| // AU.addRequiredID(BreakCriticalEdgesID); |
| // |
| // This pass obviously invalidates the CFG, but can update forward dominator |
| // (set, immediate dominators, and tree) information. |
| // |
| Pass *createBreakCriticalEdgesPass(); |
| extern const PassInfo *BreakCriticalEdgesID; |
| |
| // The BreakCriticalEdges pass also exposes some low-level functionality that |
| // may be used by other passes. |
| |
| /// isCriticalEdge - Return true if the specified edge is a critical edge. |
| /// Critical edges are edges from a block with multiple successors to a block |
| /// with multiple predecessors. |
| /// |
| bool isCriticalEdge(const TerminatorInst *TI, unsigned SuccNum); |
| |
| /// SplitCriticalEdge - Insert a new node node to split the critical edge. This |
| /// will update DominatorSet, ImmediateDominator and DominatorTree information |
| /// if a pass is specified, thus calling this pass will not invalidate these |
| /// analyses. |
| /// |
| void SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum, Pass *P = 0); |
| |
| //===----------------------------------------------------------------------===// |
| // |
| // LoopSimplify pass - Insert Pre-header blocks into the CFG for every function |
| // in the module. This pass updates dominator information, loop information, |
| // and does not add critical edges to the CFG. |
| // |
| // AU.addRequiredID(LoopSimplifyID); |
| // |
| Pass *createLoopSimplifyPass(); |
| extern const PassInfo *LoopSimplifyID; |
| |
| //===----------------------------------------------------------------------===// |
| // |
| // This pass eliminates call instructions to the current function which occur |
| // immediately before return instructions. |
| // |
| FunctionPass *createTailCallEliminationPass(); |
| |
| |
| //===----------------------------------------------------------------------===// |
| // This pass convert malloc and free instructions to %malloc & %free function |
| // calls. |
| // |
| FunctionPass *createLowerAllocationsPass(); |
| |
| //===----------------------------------------------------------------------===// |
| // This pass converts SwitchInst instructions into a sequence of chained binary |
| // branch instructions. |
| // |
| FunctionPass *createLowerSwitchPass(); |
| |
| |
| //===----------------------------------------------------------------------===// |
| // This pass converts 'invoke' instructions calls, and 'unwind' instructions |
| // into calls to abort(). |
| // |
| FunctionPass *createLowerInvokePass(); |
| |
| |
| |
| //===----------------------------------------------------------------------===// |
| // |
| // These functions removes symbols from functions and modules. |
| // |
| Pass *createSymbolStrippingPass(); |
| Pass *createFullSymbolStrippingPass(); |
| |
| #endif |