llvm-6502/include/llvm/Analysis/InstructionSimplify.h
2015-07-13 01:15:53 +00:00

359 lines
18 KiB
C++

//===-- InstructionSimplify.h - Fold instrs into simpler forms --*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file declares routines for folding instructions into simpler forms
// that do not require creating new instructions. This does constant folding
// ("add i32 1, 1" -> "2") but can also handle non-constant operands, either
// returning a constant ("and i32 %x, 0" -> "0") or an already existing value
// ("and i32 %x, %x" -> "%x"). If the simplification is also an instruction
// then it dominates the original instruction.
//
// These routines implicitly resolve undef uses. The easiest way to be safe when
// using these routines to obtain simplified values for existing instructions is
// to always replace all uses of the instructions with the resulting simplified
// values. This will prevent other code from seeing the same undef uses and
// resolving them to different values.
//
// These routines are designed to tolerate moderately incomplete IR, such as
// instructions that are not connected to basic blocks yet. However, they do
// require that all the IR that they encounter be valid. In particular, they
// require that all non-constant values be defined in the same function, and the
// same call context of that function (and not split between caller and callee
// contexts of a directly recursive call, for example).
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_INSTRUCTIONSIMPLIFY_H
#define LLVM_ANALYSIS_INSTRUCTIONSIMPLIFY_H
#include "llvm/IR/User.h"
namespace llvm {
template<typename T>
class ArrayRef;
class AssumptionCache;
class DominatorTree;
class Instruction;
class DataLayout;
class FastMathFlags;
class TargetLibraryInfo;
class Type;
class Value;
/// SimplifyAddInst - Given operands for an Add, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyAddInst(Value *LHS, Value *RHS, bool isNSW, bool isNUW,
const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr,
const Instruction *CxtI = nullptr);
/// SimplifySubInst - Given operands for a Sub, see if we can
/// fold the result. If not, this returns null.
Value *SimplifySubInst(Value *LHS, Value *RHS, bool isNSW, bool isNUW,
const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr,
const Instruction *CxtI = nullptr);
/// Given operands for an FAdd, see if we can fold the result. If not, this
/// returns null.
Value *SimplifyFAddInst(Value *LHS, Value *RHS, FastMathFlags FMF,
const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr,
const Instruction *CxtI = nullptr);
/// Given operands for an FSub, see if we can fold the result. If not, this
/// returns null.
Value *SimplifyFSubInst(Value *LHS, Value *RHS, FastMathFlags FMF,
const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr,
const Instruction *CxtI = nullptr);
/// Given operands for an FMul, see if we can fold the result. If not, this
/// returns null.
Value *SimplifyFMulInst(Value *LHS, Value *RHS, FastMathFlags FMF,
const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr,
const Instruction *CxtI = nullptr);
/// SimplifyMulInst - Given operands for a Mul, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyMulInst(Value *LHS, Value *RHS, const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr,
const Instruction *CxtI = nullptr);
/// SimplifySDivInst - Given operands for an SDiv, see if we can
/// fold the result. If not, this returns null.
Value *SimplifySDivInst(Value *LHS, Value *RHS, const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr,
const Instruction *CxtI = nullptr);
/// SimplifyUDivInst - Given operands for a UDiv, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyUDivInst(Value *LHS, Value *RHS, const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr,
const Instruction *CxtI = nullptr);
/// SimplifyFDivInst - Given operands for an FDiv, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyFDivInst(Value *LHS, Value *RHS, FastMathFlags FMF,
const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr,
const Instruction *CxtI = nullptr);
/// SimplifySRemInst - Given operands for an SRem, see if we can
/// fold the result. If not, this returns null.
Value *SimplifySRemInst(Value *LHS, Value *RHS, const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr,
const Instruction *CxtI = nullptr);
/// SimplifyURemInst - Given operands for a URem, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyURemInst(Value *LHS, Value *RHS, const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr,
const Instruction *CxtI = nullptr);
/// SimplifyFRemInst - Given operands for an FRem, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyFRemInst(Value *LHS, Value *RHS, FastMathFlags FMF,
const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr,
const Instruction *CxtI = nullptr);
/// SimplifyShlInst - Given operands for a Shl, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr,
const Instruction *CxtI = nullptr);
/// SimplifyLShrInst - Given operands for a LShr, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr,
const Instruction *CxtI = nullptr);
/// SimplifyAShrInst - Given operands for a AShr, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr,
const Instruction *CxtI = nullptr);
/// SimplifyAndInst - Given operands for an And, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyAndInst(Value *LHS, Value *RHS, const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr,
const Instruction *CxtI = nullptr);
/// SimplifyOrInst - Given operands for an Or, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyOrInst(Value *LHS, Value *RHS, const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr,
const Instruction *CxtI = nullptr);
/// SimplifyXorInst - Given operands for a Xor, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyXorInst(Value *LHS, Value *RHS, const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr,
const Instruction *CxtI = nullptr);
/// SimplifyICmpInst - Given operands for an ICmpInst, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr,
Instruction *CxtI = nullptr);
/// SimplifyFCmpInst - Given operands for an FCmpInst, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
FastMathFlags FMF, const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr,
const Instruction *CxtI = nullptr);
/// SimplifySelectInst - Given operands for a SelectInst, see if we can fold
/// the result. If not, this returns null.
Value *SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr,
const Instruction *CxtI = nullptr);
/// SimplifyGEPInst - Given operands for an GetElementPtrInst, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyGEPInst(ArrayRef<Value *> Ops, const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr,
const Instruction *CxtI = nullptr);
/// SimplifyInsertValueInst - Given operands for an InsertValueInst, see if we
/// can fold the result. If not, this returns null.
Value *SimplifyInsertValueInst(Value *Agg, Value *Val,
ArrayRef<unsigned> Idxs, const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr,
const Instruction *CxtI = nullptr);
/// \brief Given operands for an ExtractValueInst, see if we can fold the
/// result. If not, this returns null.
Value *SimplifyExtractValueInst(Value *Agg, ArrayRef<unsigned> Idxs,
const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr,
const Instruction *CxtI = nullptr);
/// \brief Given operands for an ExtractElementInst, see if we can fold the
/// result. If not, this returns null.
Value *SimplifyExtractElementInst(Value *Vec, Value *Idx,
const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr,
const Instruction *CxtI = nullptr);
/// SimplifyTruncInst - Given operands for an TruncInst, see if we can fold
/// the result. If not, this returns null.
Value *SimplifyTruncInst(Value *Op, Type *Ty, const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr,
const Instruction *CxtI = nullptr);
//=== Helper functions for higher up the class hierarchy.
/// SimplifyCmpInst - Given operands for a CmpInst, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr,
const Instruction *CxtI = nullptr);
/// SimplifyBinOp - Given operands for a BinaryOperator, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr,
const Instruction *CxtI = nullptr);
/// SimplifyFPBinOp - Given operands for a BinaryOperator, see if we can
/// fold the result. If not, this returns null.
/// In contrast to SimplifyBinOp, try to use FastMathFlag when folding the
/// result. In case we don't need FastMathFlags, simply fall to SimplifyBinOp.
Value *SimplifyFPBinOp(unsigned Opcode, Value *LHS, Value *RHS,
const FastMathFlags &FMF, const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr,
const Instruction *CxtI = nullptr);
/// \brief Given a function and iterators over arguments, see if we can fold
/// the result.
///
/// If this call could not be simplified returns null.
Value *SimplifyCall(Value *V, User::op_iterator ArgBegin,
User::op_iterator ArgEnd, const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr,
const Instruction *CxtI = nullptr);
/// \brief Given a function and set of arguments, see if we can fold the
/// result.
///
/// If this call could not be simplified returns null.
Value *SimplifyCall(Value *V, ArrayRef<Value *> Args, const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr,
const Instruction *CxtI = nullptr);
/// SimplifyInstruction - See if we can compute a simplified version of this
/// instruction. If not, this returns null.
Value *SimplifyInstruction(Instruction *I, const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr);
/// \brief Replace all uses of 'I' with 'SimpleV' and simplify the uses
/// recursively.
///
/// This first performs a normal RAUW of I with SimpleV. It then recursively
/// attempts to simplify those users updated by the operation. The 'I'
/// instruction must not be equal to the simplified value 'SimpleV'.
///
/// The function returns true if any simplifications were performed.
bool replaceAndRecursivelySimplify(Instruction *I, Value *SimpleV,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr);
/// \brief Recursively attempt to simplify an instruction.
///
/// This routine uses SimplifyInstruction to simplify 'I', and if successful
/// replaces uses of 'I' with the simplified value. It then recurses on each
/// of the users impacted. It returns true if any simplifications were
/// performed.
bool recursivelySimplifyInstruction(Instruction *I,
const TargetLibraryInfo *TLI = nullptr,
const DominatorTree *DT = nullptr,
AssumptionCache *AC = nullptr);
} // end namespace llvm
#endif