| //===-- InstructionSimplify.h - Fold instrs into simpler forms --*- C++ -*-===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // 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/Instruction.h" |
| #include "llvm/IR/Operator.h" |
| #include "llvm/IR/User.h" |
| |
| namespace llvm { |
| class Function; |
| template <typename T, typename... TArgs> class AnalysisManager; |
| template <class T> class ArrayRef; |
| class AssumptionCache; |
| class CallBase; |
| class DominatorTree; |
| class DataLayout; |
| class FastMathFlags; |
| struct LoopStandardAnalysisResults; |
| class OptimizationRemarkEmitter; |
| class Pass; |
| class TargetLibraryInfo; |
| class Type; |
| class Value; |
| class MDNode; |
| class BinaryOperator; |
| |
| /// InstrInfoQuery provides an interface to query additional information for |
| /// instructions like metadata or keywords like nsw, which provides conservative |
| /// results if the users specified it is safe to use. |
| struct InstrInfoQuery { |
| InstrInfoQuery(bool UMD) : UseInstrInfo(UMD) {} |
| InstrInfoQuery() : UseInstrInfo(true) {} |
| bool UseInstrInfo = true; |
| |
| MDNode *getMetadata(const Instruction *I, unsigned KindID) const { |
| if (UseInstrInfo) |
| return I->getMetadata(KindID); |
| return nullptr; |
| } |
| |
| template <class InstT> bool hasNoUnsignedWrap(const InstT *Op) const { |
| if (UseInstrInfo) |
| return Op->hasNoUnsignedWrap(); |
| return false; |
| } |
| |
| template <class InstT> bool hasNoSignedWrap(const InstT *Op) const { |
| if (UseInstrInfo) |
| return Op->hasNoSignedWrap(); |
| return false; |
| } |
| |
| bool isExact(const BinaryOperator *Op) const { |
| if (UseInstrInfo && isa<PossiblyExactOperator>(Op)) |
| return cast<PossiblyExactOperator>(Op)->isExact(); |
| return false; |
| } |
| }; |
| |
| struct SimplifyQuery { |
| const DataLayout &DL; |
| const TargetLibraryInfo *TLI = nullptr; |
| const DominatorTree *DT = nullptr; |
| AssumptionCache *AC = nullptr; |
| const Instruction *CxtI = nullptr; |
| |
| // Wrapper to query additional information for instructions like metadata or |
| // keywords like nsw, which provides conservative results if those cannot |
| // be safely used. |
| const InstrInfoQuery IIQ; |
| |
| SimplifyQuery(const DataLayout &DL, const Instruction *CXTI = nullptr) |
| : DL(DL), CxtI(CXTI) {} |
| |
| SimplifyQuery(const DataLayout &DL, const TargetLibraryInfo *TLI, |
| const DominatorTree *DT = nullptr, |
| AssumptionCache *AC = nullptr, |
| const Instruction *CXTI = nullptr, bool UseInstrInfo = true) |
| : DL(DL), TLI(TLI), DT(DT), AC(AC), CxtI(CXTI), IIQ(UseInstrInfo) {} |
| SimplifyQuery getWithInstruction(Instruction *I) const { |
| SimplifyQuery Copy(*this); |
| Copy.CxtI = I; |
| return Copy; |
| } |
| }; |
| |
| // NOTE: the explicit multiple argument versions of these functions are |
| // deprecated. |
| // Please use the SimplifyQuery versions in new code. |
| |
| /// Given operand for an FNeg, fold the result or return null. |
| Value *SimplifyFNegInst(Value *Op, FastMathFlags FMF, |
| const SimplifyQuery &Q); |
| |
| /// Given operands for an Add, fold the result or return null. |
| Value *SimplifyAddInst(Value *LHS, Value *RHS, bool isNSW, bool isNUW, |
| const SimplifyQuery &Q); |
| |
| /// Given operands for a Sub, fold the result or return null. |
| Value *SimplifySubInst(Value *LHS, Value *RHS, bool isNSW, bool isNUW, |
| const SimplifyQuery &Q); |
| |
| /// Given operands for an FAdd, fold the result or return null. |
| Value *SimplifyFAddInst(Value *LHS, Value *RHS, FastMathFlags FMF, |
| const SimplifyQuery &Q); |
| |
| /// Given operands for an FSub, fold the result or return null. |
| Value *SimplifyFSubInst(Value *LHS, Value *RHS, FastMathFlags FMF, |
| const SimplifyQuery &Q); |
| |
| /// Given operands for an FMul, fold the result or return null. |
| Value *SimplifyFMulInst(Value *LHS, Value *RHS, FastMathFlags FMF, |
| const SimplifyQuery &Q); |
| |
| /// Given operands for a Mul, fold the result or return null. |
| Value *SimplifyMulInst(Value *LHS, Value *RHS, const SimplifyQuery &Q); |
| |
| /// Given operands for an SDiv, fold the result or return null. |
| Value *SimplifySDivInst(Value *LHS, Value *RHS, const SimplifyQuery &Q); |
| |
| /// Given operands for a UDiv, fold the result or return null. |
| Value *SimplifyUDivInst(Value *LHS, Value *RHS, const SimplifyQuery &Q); |
| |
| /// Given operands for an FDiv, fold the result or return null. |
| Value *SimplifyFDivInst(Value *LHS, Value *RHS, FastMathFlags FMF, |
| const SimplifyQuery &Q); |
| |
| /// Given operands for an SRem, fold the result or return null. |
| Value *SimplifySRemInst(Value *LHS, Value *RHS, const SimplifyQuery &Q); |
| |
| /// Given operands for a URem, fold the result or return null. |
| Value *SimplifyURemInst(Value *LHS, Value *RHS, const SimplifyQuery &Q); |
| |
| /// Given operands for an FRem, fold the result or return null. |
| Value *SimplifyFRemInst(Value *LHS, Value *RHS, FastMathFlags FMF, |
| const SimplifyQuery &Q); |
| |
| /// Given operands for a Shl, fold the result or return null. |
| Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW, |
| const SimplifyQuery &Q); |
| |
| /// Given operands for a LShr, fold the result or return null. |
| Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact, |
| const SimplifyQuery &Q); |
| |
| /// Given operands for a AShr, fold the result or return nulll. |
| Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact, |
| const SimplifyQuery &Q); |
| |
| /// Given operands for an And, fold the result or return null. |
| Value *SimplifyAndInst(Value *LHS, Value *RHS, const SimplifyQuery &Q); |
| |
| /// Given operands for an Or, fold the result or return null. |
| Value *SimplifyOrInst(Value *LHS, Value *RHS, const SimplifyQuery &Q); |
| |
| /// Given operands for an Xor, fold the result or return null. |
| Value *SimplifyXorInst(Value *LHS, Value *RHS, const SimplifyQuery &Q); |
| |
| /// Given operands for an ICmpInst, fold the result or return null. |
| Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS, |
| const SimplifyQuery &Q); |
| |
| /// Given operands for an FCmpInst, fold the result or return null. |
| Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS, |
| FastMathFlags FMF, const SimplifyQuery &Q); |
| |
| /// Given operands for a SelectInst, fold the result or return null. |
| Value *SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal, |
| const SimplifyQuery &Q); |
| |
| /// Given operands for a GetElementPtrInst, fold the result or return null. |
| Value *SimplifyGEPInst(Type *SrcTy, ArrayRef<Value *> Ops, |
| const SimplifyQuery &Q); |
| |
| /// Given operands for an InsertValueInst, fold the result or return null. |
| Value *SimplifyInsertValueInst(Value *Agg, Value *Val, ArrayRef<unsigned> Idxs, |
| const SimplifyQuery &Q); |
| |
| /// Given operands for an InsertElement, fold the result or return null. |
| Value *SimplifyInsertElementInst(Value *Vec, Value *Elt, Value *Idx, |
| const SimplifyQuery &Q); |
| |
| /// Given operands for an ExtractValueInst, fold the result or return null. |
| Value *SimplifyExtractValueInst(Value *Agg, ArrayRef<unsigned> Idxs, |
| const SimplifyQuery &Q); |
| |
| /// Given operands for an ExtractElementInst, fold the result or return null. |
| Value *SimplifyExtractElementInst(Value *Vec, Value *Idx, |
| const SimplifyQuery &Q); |
| |
| /// Given operands for a CastInst, fold the result or return null. |
| Value *SimplifyCastInst(unsigned CastOpc, Value *Op, Type *Ty, |
| const SimplifyQuery &Q); |
| |
| /// Given operands for a ShuffleVectorInst, fold the result or return null. |
| Value *SimplifyShuffleVectorInst(Value *Op0, Value *Op1, Constant *Mask, |
| Type *RetTy, const SimplifyQuery &Q); |
| |
| //=== Helper functions for higher up the class hierarchy. |
| |
| /// Given operands for a CmpInst, fold the result or return null. |
| Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS, |
| const SimplifyQuery &Q); |
| |
| /// Given operand for a UnaryOperator, fold the result or return null. |
| Value *SimplifyUnOp(unsigned Opcode, Value *Op, const SimplifyQuery &Q); |
| |
| /// Given operand for an FP UnaryOperator, fold the result or return null. |
| /// In contrast to SimplifyUnOp, try to use FastMathFlag when folding the |
| /// result. In case we don't need FastMathFlags, simply fall to SimplifyUnOp. |
| Value *SimplifyFPUnOp(unsigned Opcode, Value *Op, FastMathFlags FMF, |
| const SimplifyQuery &Q); |
| |
| /// Given operands for a BinaryOperator, fold the result or return null. |
| Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS, |
| const SimplifyQuery &Q); |
| |
| /// Given operands for an FP BinaryOperator, fold the result or return 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, |
| FastMathFlags FMF, const SimplifyQuery &Q); |
| |
| /// Given a callsite, fold the result or return null. |
| Value *SimplifyCall(CallBase *Call, const SimplifyQuery &Q); |
| |
| /// Given a function and iterators over arguments, fold the result or return |
| /// null. |
| Value *SimplifyCall(CallBase *Call, Value *V, User::op_iterator ArgBegin, |
| User::op_iterator ArgEnd, const SimplifyQuery &Q); |
| |
| /// Given a function and set of arguments, fold the result or return null. |
| Value *SimplifyCall(CallBase *Call, Value *V, ArrayRef<Value *> Args, |
| const SimplifyQuery &Q); |
| |
| /// See if we can compute a simplified version of this instruction. If not, |
| /// return null. |
| Value *SimplifyInstruction(Instruction *I, const SimplifyQuery &Q, |
| OptimizationRemarkEmitter *ORE = nullptr); |
| |
| /// 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); |
| |
| /// 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); |
| |
| // These helper functions return a SimplifyQuery structure that contains as |
| // many of the optional analysis we use as are currently valid. This is the |
| // strongly preferred way of constructing SimplifyQuery in passes. |
| const SimplifyQuery getBestSimplifyQuery(Pass &, Function &); |
| template <class T, class... TArgs> |
| const SimplifyQuery getBestSimplifyQuery(AnalysisManager<T, TArgs...> &, |
| Function &); |
| const SimplifyQuery getBestSimplifyQuery(LoopStandardAnalysisResults &, |
| const DataLayout &); |
| } // end namespace llvm |
| |
| #endif |
| |