/usr/include/llvm-5.0/llvm/Analysis/DemandedBits.h is in llvm-5.0-dev 1:5.0.1-4.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 | //===-- llvm/Analysis/DemandedBits.h - Determine demanded bits --*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This pass implements a demanded bits analysis. A demanded bit is one that
// contributes to a result; bits that are not demanded can be either zero or
// one without affecting control or data flow. For example in this sequence:
//
// %1 = add i32 %x, %y
// %2 = trunc i32 %1 to i16
//
// Only the lowest 16 bits of %1 are demanded; the rest are removed by the
// trunc.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_DEMANDED_BITS_H
#define LLVM_ANALYSIS_DEMANDED_BITS_H
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/IR/PassManager.h"
#include "llvm/Pass.h"
namespace llvm {
class FunctionPass;
class Function;
class Instruction;
class DominatorTree;
class AssumptionCache;
struct KnownBits;
class DemandedBits {
public:
DemandedBits(Function &F, AssumptionCache &AC, DominatorTree &DT) :
F(F), AC(AC), DT(DT), Analyzed(false) {}
/// Return the bits demanded from instruction I.
APInt getDemandedBits(Instruction *I);
/// Return true if, during analysis, I could not be reached.
bool isInstructionDead(Instruction *I);
void print(raw_ostream &OS);
private:
Function &F;
AssumptionCache ∾
DominatorTree &DT;
void performAnalysis();
void determineLiveOperandBits(const Instruction *UserI,
const Instruction *I, unsigned OperandNo,
const APInt &AOut, APInt &AB,
KnownBits &Known, KnownBits &Known2);
bool Analyzed;
// The set of visited instructions (non-integer-typed only).
SmallPtrSet<Instruction*, 32> Visited;
DenseMap<Instruction *, APInt> AliveBits;
};
class DemandedBitsWrapperPass : public FunctionPass {
private:
mutable Optional<DemandedBits> DB;
public:
static char ID; // Pass identification, replacement for typeid
DemandedBitsWrapperPass();
bool runOnFunction(Function &F) override;
void getAnalysisUsage(AnalysisUsage &AU) const override;
/// Clean up memory in between runs
void releaseMemory() override;
DemandedBits &getDemandedBits() { return *DB; }
void print(raw_ostream &OS, const Module *M) const override;
};
/// An analysis that produces \c DemandedBits for a function.
class DemandedBitsAnalysis : public AnalysisInfoMixin<DemandedBitsAnalysis> {
friend AnalysisInfoMixin<DemandedBitsAnalysis>;
static AnalysisKey Key;
public:
/// \brief Provide the result typedef for this analysis pass.
typedef DemandedBits Result;
/// \brief Run the analysis pass over a function and produce demanded bits
/// information.
DemandedBits run(Function &F, FunctionAnalysisManager &AM);
};
/// \brief Printer pass for DemandedBits
class DemandedBitsPrinterPass : public PassInfoMixin<DemandedBitsPrinterPass> {
raw_ostream &OS;
public:
explicit DemandedBitsPrinterPass(raw_ostream &OS) : OS(OS) {}
PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
};
/// Create a demanded bits analysis pass.
FunctionPass *createDemandedBitsWrapperPass();
} // End llvm namespace
#endif
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