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1e1446bf84
This logic hadn't been updated to handle FastMathFlags, and it took me a while to detect it because it doesn't show up in a simple search for CreateFAdd. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199629 91177308-0d34-0410-b5e6-96231b3b80d8
1579 lines
50 KiB
C++
1579 lines
50 KiB
C++
//===- InstCombineAddSub.cpp ----------------------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the visit functions for add, fadd, sub, and fsub.
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//
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//===----------------------------------------------------------------------===//
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#include "InstCombine.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/Analysis/InstructionSimplify.h"
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#include "llvm/IR/DataLayout.h"
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#include "llvm/Support/GetElementPtrTypeIterator.h"
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#include "llvm/Support/PatternMatch.h"
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using namespace llvm;
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using namespace PatternMatch;
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namespace {
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/// Class representing coefficient of floating-point addend.
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/// This class needs to be highly efficient, which is especially true for
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/// the constructor. As of I write this comment, the cost of the default
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/// constructor is merely 4-byte-store-zero (Assuming compiler is able to
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/// perform write-merging).
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///
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class FAddendCoef {
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public:
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// The constructor has to initialize a APFloat, which is uncessary for
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// most addends which have coefficient either 1 or -1. So, the constructor
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// is expensive. In order to avoid the cost of the constructor, we should
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// reuse some instances whenever possible. The pre-created instances
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// FAddCombine::Add[0-5] embodies this idea.
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//
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FAddendCoef() : IsFp(false), BufHasFpVal(false), IntVal(0) {}
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~FAddendCoef();
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void set(short C) {
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assert(!insaneIntVal(C) && "Insane coefficient");
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IsFp = false; IntVal = C;
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}
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void set(const APFloat& C);
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void negate();
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bool isZero() const { return isInt() ? !IntVal : getFpVal().isZero(); }
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Value *getValue(Type *) const;
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// If possible, don't define operator+/operator- etc because these
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// operators inevitably call FAddendCoef's constructor which is not cheap.
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void operator=(const FAddendCoef &A);
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void operator+=(const FAddendCoef &A);
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void operator-=(const FAddendCoef &A);
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void operator*=(const FAddendCoef &S);
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bool isOne() const { return isInt() && IntVal == 1; }
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bool isTwo() const { return isInt() && IntVal == 2; }
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bool isMinusOne() const { return isInt() && IntVal == -1; }
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bool isMinusTwo() const { return isInt() && IntVal == -2; }
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private:
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bool insaneIntVal(int V) { return V > 4 || V < -4; }
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APFloat *getFpValPtr(void)
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{ return reinterpret_cast<APFloat*>(&FpValBuf.buffer[0]); }
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const APFloat *getFpValPtr(void) const
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{ return reinterpret_cast<const APFloat*>(&FpValBuf.buffer[0]); }
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const APFloat &getFpVal(void) const {
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assert(IsFp && BufHasFpVal && "Incorret state");
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return *getFpValPtr();
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}
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APFloat &getFpVal(void) {
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assert(IsFp && BufHasFpVal && "Incorret state");
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return *getFpValPtr();
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}
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bool isInt() const { return !IsFp; }
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// If the coefficient is represented by an integer, promote it to a
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// floating point.
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void convertToFpType(const fltSemantics &Sem);
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// Construct an APFloat from a signed integer.
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// TODO: We should get rid of this function when APFloat can be constructed
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// from an *SIGNED* integer.
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APFloat createAPFloatFromInt(const fltSemantics &Sem, int Val);
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private:
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bool IsFp;
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// True iff FpValBuf contains an instance of APFloat.
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bool BufHasFpVal;
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// The integer coefficient of an individual addend is either 1 or -1,
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// and we try to simplify at most 4 addends from neighboring at most
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// two instructions. So the range of <IntVal> falls in [-4, 4]. APInt
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// is overkill of this end.
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short IntVal;
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AlignedCharArrayUnion<APFloat> FpValBuf;
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};
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/// FAddend is used to represent floating-point addend. An addend is
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/// represented as <C, V>, where the V is a symbolic value, and C is a
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/// constant coefficient. A constant addend is represented as <C, 0>.
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///
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class FAddend {
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public:
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FAddend() { Val = 0; }
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Value *getSymVal (void) const { return Val; }
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const FAddendCoef &getCoef(void) const { return Coeff; }
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bool isConstant() const { return Val == 0; }
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bool isZero() const { return Coeff.isZero(); }
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void set(short Coefficient, Value *V) { Coeff.set(Coefficient), Val = V; }
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void set(const APFloat& Coefficient, Value *V)
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{ Coeff.set(Coefficient); Val = V; }
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void set(const ConstantFP* Coefficient, Value *V)
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{ Coeff.set(Coefficient->getValueAPF()); Val = V; }
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void negate() { Coeff.negate(); }
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/// Drill down the U-D chain one step to find the definition of V, and
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/// try to break the definition into one or two addends.
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static unsigned drillValueDownOneStep(Value* V, FAddend &A0, FAddend &A1);
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/// Similar to FAddend::drillDownOneStep() except that the value being
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/// splitted is the addend itself.
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unsigned drillAddendDownOneStep(FAddend &Addend0, FAddend &Addend1) const;
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void operator+=(const FAddend &T) {
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assert((Val == T.Val) && "Symbolic-values disagree");
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Coeff += T.Coeff;
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}
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private:
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void Scale(const FAddendCoef& ScaleAmt) { Coeff *= ScaleAmt; }
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// This addend has the value of "Coeff * Val".
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Value *Val;
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FAddendCoef Coeff;
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};
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/// FAddCombine is the class for optimizing an unsafe fadd/fsub along
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/// with its neighboring at most two instructions.
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///
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class FAddCombine {
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public:
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FAddCombine(InstCombiner::BuilderTy *B) : Builder(B), Instr(0) {}
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Value *simplify(Instruction *FAdd);
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private:
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typedef SmallVector<const FAddend*, 4> AddendVect;
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Value *simplifyFAdd(AddendVect& V, unsigned InstrQuota);
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Value *performFactorization(Instruction *I);
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/// Convert given addend to a Value
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Value *createAddendVal(const FAddend &A, bool& NeedNeg);
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/// Return the number of instructions needed to emit the N-ary addition.
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unsigned calcInstrNumber(const AddendVect& Vect);
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Value *createFSub(Value *Opnd0, Value *Opnd1);
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Value *createFAdd(Value *Opnd0, Value *Opnd1);
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Value *createFMul(Value *Opnd0, Value *Opnd1);
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Value *createFDiv(Value *Opnd0, Value *Opnd1);
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Value *createFNeg(Value *V);
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Value *createNaryFAdd(const AddendVect& Opnds, unsigned InstrQuota);
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void createInstPostProc(Instruction *NewInst, bool NoNumber = false);
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InstCombiner::BuilderTy *Builder;
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Instruction *Instr;
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private:
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// Debugging stuff are clustered here.
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#ifndef NDEBUG
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unsigned CreateInstrNum;
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void initCreateInstNum() { CreateInstrNum = 0; }
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void incCreateInstNum() { CreateInstrNum++; }
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#else
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void initCreateInstNum() {}
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void incCreateInstNum() {}
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#endif
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};
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}
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//===----------------------------------------------------------------------===//
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//
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// Implementation of
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// {FAddendCoef, FAddend, FAddition, FAddCombine}.
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//
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//===----------------------------------------------------------------------===//
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FAddendCoef::~FAddendCoef() {
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if (BufHasFpVal)
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getFpValPtr()->~APFloat();
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}
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void FAddendCoef::set(const APFloat& C) {
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APFloat *P = getFpValPtr();
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if (isInt()) {
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// As the buffer is meanless byte stream, we cannot call
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// APFloat::operator=().
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new(P) APFloat(C);
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} else
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*P = C;
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IsFp = BufHasFpVal = true;
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}
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void FAddendCoef::convertToFpType(const fltSemantics &Sem) {
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if (!isInt())
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return;
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APFloat *P = getFpValPtr();
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if (IntVal > 0)
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new(P) APFloat(Sem, IntVal);
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else {
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new(P) APFloat(Sem, 0 - IntVal);
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P->changeSign();
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}
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IsFp = BufHasFpVal = true;
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}
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APFloat FAddendCoef::createAPFloatFromInt(const fltSemantics &Sem, int Val) {
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if (Val >= 0)
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return APFloat(Sem, Val);
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APFloat T(Sem, 0 - Val);
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T.changeSign();
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return T;
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}
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void FAddendCoef::operator=(const FAddendCoef &That) {
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if (That.isInt())
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set(That.IntVal);
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else
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set(That.getFpVal());
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}
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void FAddendCoef::operator+=(const FAddendCoef &That) {
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enum APFloat::roundingMode RndMode = APFloat::rmNearestTiesToEven;
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if (isInt() == That.isInt()) {
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if (isInt())
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IntVal += That.IntVal;
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else
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getFpVal().add(That.getFpVal(), RndMode);
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return;
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}
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if (isInt()) {
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const APFloat &T = That.getFpVal();
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convertToFpType(T.getSemantics());
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getFpVal().add(T, RndMode);
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return;
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}
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APFloat &T = getFpVal();
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T.add(createAPFloatFromInt(T.getSemantics(), That.IntVal), RndMode);
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}
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void FAddendCoef::operator-=(const FAddendCoef &That) {
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enum APFloat::roundingMode RndMode = APFloat::rmNearestTiesToEven;
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if (isInt() == That.isInt()) {
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if (isInt())
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IntVal -= That.IntVal;
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else
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getFpVal().subtract(That.getFpVal(), RndMode);
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return;
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}
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if (isInt()) {
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const APFloat &T = That.getFpVal();
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convertToFpType(T.getSemantics());
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getFpVal().subtract(T, RndMode);
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return;
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}
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APFloat &T = getFpVal();
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T.subtract(createAPFloatFromInt(T.getSemantics(), IntVal), RndMode);
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}
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void FAddendCoef::operator*=(const FAddendCoef &That) {
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if (That.isOne())
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return;
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if (That.isMinusOne()) {
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negate();
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return;
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}
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if (isInt() && That.isInt()) {
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int Res = IntVal * (int)That.IntVal;
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assert(!insaneIntVal(Res) && "Insane int value");
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IntVal = Res;
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return;
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}
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const fltSemantics &Semantic =
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isInt() ? That.getFpVal().getSemantics() : getFpVal().getSemantics();
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if (isInt())
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convertToFpType(Semantic);
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APFloat &F0 = getFpVal();
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if (That.isInt())
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F0.multiply(createAPFloatFromInt(Semantic, That.IntVal),
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APFloat::rmNearestTiesToEven);
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else
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F0.multiply(That.getFpVal(), APFloat::rmNearestTiesToEven);
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return;
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}
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void FAddendCoef::negate() {
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if (isInt())
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IntVal = 0 - IntVal;
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else
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getFpVal().changeSign();
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}
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Value *FAddendCoef::getValue(Type *Ty) const {
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return isInt() ?
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ConstantFP::get(Ty, float(IntVal)) :
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ConstantFP::get(Ty->getContext(), getFpVal());
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}
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// The definition of <Val> Addends
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// =========================================
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// A + B <1, A>, <1,B>
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// A - B <1, A>, <1,B>
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// 0 - B <-1, B>
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// C * A, <C, A>
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// A + C <1, A> <C, NULL>
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// 0 +/- 0 <0, NULL> (corner case)
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//
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// Legend: A and B are not constant, C is constant
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//
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unsigned FAddend::drillValueDownOneStep
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(Value *Val, FAddend &Addend0, FAddend &Addend1) {
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Instruction *I = 0;
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if (Val == 0 || !(I = dyn_cast<Instruction>(Val)))
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return 0;
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unsigned Opcode = I->getOpcode();
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if (Opcode == Instruction::FAdd || Opcode == Instruction::FSub) {
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ConstantFP *C0, *C1;
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Value *Opnd0 = I->getOperand(0);
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Value *Opnd1 = I->getOperand(1);
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if ((C0 = dyn_cast<ConstantFP>(Opnd0)) && C0->isZero())
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Opnd0 = 0;
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if ((C1 = dyn_cast<ConstantFP>(Opnd1)) && C1->isZero())
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Opnd1 = 0;
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if (Opnd0) {
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if (!C0)
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Addend0.set(1, Opnd0);
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else
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Addend0.set(C0, 0);
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}
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if (Opnd1) {
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FAddend &Addend = Opnd0 ? Addend1 : Addend0;
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if (!C1)
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Addend.set(1, Opnd1);
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else
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Addend.set(C1, 0);
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if (Opcode == Instruction::FSub)
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Addend.negate();
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}
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if (Opnd0 || Opnd1)
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return Opnd0 && Opnd1 ? 2 : 1;
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// Both operands are zero. Weird!
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Addend0.set(APFloat(C0->getValueAPF().getSemantics()), 0);
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return 1;
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}
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if (I->getOpcode() == Instruction::FMul) {
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Value *V0 = I->getOperand(0);
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Value *V1 = I->getOperand(1);
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if (ConstantFP *C = dyn_cast<ConstantFP>(V0)) {
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Addend0.set(C, V1);
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return 1;
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}
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if (ConstantFP *C = dyn_cast<ConstantFP>(V1)) {
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Addend0.set(C, V0);
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return 1;
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}
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}
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return 0;
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}
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// Try to break *this* addend into two addends. e.g. Suppose this addend is
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// <2.3, V>, and V = X + Y, by calling this function, we obtain two addends,
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// i.e. <2.3, X> and <2.3, Y>.
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//
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unsigned FAddend::drillAddendDownOneStep
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(FAddend &Addend0, FAddend &Addend1) const {
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if (isConstant())
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return 0;
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unsigned BreakNum = FAddend::drillValueDownOneStep(Val, Addend0, Addend1);
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if (!BreakNum || Coeff.isOne())
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return BreakNum;
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Addend0.Scale(Coeff);
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if (BreakNum == 2)
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Addend1.Scale(Coeff);
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return BreakNum;
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}
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// Try to perform following optimization on the input instruction I. Return the
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// simplified expression if was successful; otherwise, return 0.
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//
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// Instruction "I" is Simplified into
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// -------------------------------------------------------
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// (x * y) +/- (x * z) x * (y +/- z)
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// (y / x) +/- (z / x) (y +/- z) / x
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//
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Value *FAddCombine::performFactorization(Instruction *I) {
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assert((I->getOpcode() == Instruction::FAdd ||
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I->getOpcode() == Instruction::FSub) && "Expect add/sub");
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Instruction *I0 = dyn_cast<Instruction>(I->getOperand(0));
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Instruction *I1 = dyn_cast<Instruction>(I->getOperand(1));
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if (!I0 || !I1 || I0->getOpcode() != I1->getOpcode())
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return 0;
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bool isMpy = false;
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if (I0->getOpcode() == Instruction::FMul)
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isMpy = true;
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else if (I0->getOpcode() != Instruction::FDiv)
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return 0;
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Value *Opnd0_0 = I0->getOperand(0);
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Value *Opnd0_1 = I0->getOperand(1);
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Value *Opnd1_0 = I1->getOperand(0);
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Value *Opnd1_1 = I1->getOperand(1);
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// Input Instr I Factor AddSub0 AddSub1
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// ----------------------------------------------
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// (x*y) +/- (x*z) x y z
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// (y/x) +/- (z/x) x y z
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//
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Value *Factor = 0;
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Value *AddSub0 = 0, *AddSub1 = 0;
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if (isMpy) {
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if (Opnd0_0 == Opnd1_0 || Opnd0_0 == Opnd1_1)
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Factor = Opnd0_0;
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else if (Opnd0_1 == Opnd1_0 || Opnd0_1 == Opnd1_1)
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Factor = Opnd0_1;
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if (Factor) {
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AddSub0 = (Factor == Opnd0_0) ? Opnd0_1 : Opnd0_0;
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AddSub1 = (Factor == Opnd1_0) ? Opnd1_1 : Opnd1_0;
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}
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} else if (Opnd0_1 == Opnd1_1) {
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Factor = Opnd0_1;
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AddSub0 = Opnd0_0;
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AddSub1 = Opnd1_0;
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}
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if (!Factor)
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return 0;
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FastMathFlags Flags;
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Flags.setUnsafeAlgebra();
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if (I0) Flags &= I->getFastMathFlags();
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if (I1) Flags &= I->getFastMathFlags();
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// Create expression "NewAddSub = AddSub0 +/- AddsSub1"
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Value *NewAddSub = (I->getOpcode() == Instruction::FAdd) ?
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createFAdd(AddSub0, AddSub1) :
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createFSub(AddSub0, AddSub1);
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if (ConstantFP *CFP = dyn_cast<ConstantFP>(NewAddSub)) {
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const APFloat &F = CFP->getValueAPF();
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|
if (!F.isNormal())
|
|
return 0;
|
|
} else if (Instruction *II = dyn_cast<Instruction>(NewAddSub))
|
|
II->setFastMathFlags(Flags);
|
|
|
|
if (isMpy) {
|
|
Value *RI = createFMul(Factor, NewAddSub);
|
|
if (Instruction *II = dyn_cast<Instruction>(RI))
|
|
II->setFastMathFlags(Flags);
|
|
return RI;
|
|
}
|
|
|
|
Value *RI = createFDiv(NewAddSub, Factor);
|
|
if (Instruction *II = dyn_cast<Instruction>(RI))
|
|
II->setFastMathFlags(Flags);
|
|
return RI;
|
|
}
|
|
|
|
Value *FAddCombine::simplify(Instruction *I) {
|
|
assert(I->hasUnsafeAlgebra() && "Should be in unsafe mode");
|
|
|
|
// Currently we are not able to handle vector type.
|
|
if (I->getType()->isVectorTy())
|
|
return 0;
|
|
|
|
assert((I->getOpcode() == Instruction::FAdd ||
|
|
I->getOpcode() == Instruction::FSub) && "Expect add/sub");
|
|
|
|
// Save the instruction before calling other member-functions.
|
|
Instr = I;
|
|
|
|
FAddend Opnd0, Opnd1, Opnd0_0, Opnd0_1, Opnd1_0, Opnd1_1;
|
|
|
|
unsigned OpndNum = FAddend::drillValueDownOneStep(I, Opnd0, Opnd1);
|
|
|
|
// Step 1: Expand the 1st addend into Opnd0_0 and Opnd0_1.
|
|
unsigned Opnd0_ExpNum = 0;
|
|
unsigned Opnd1_ExpNum = 0;
|
|
|
|
if (!Opnd0.isConstant())
|
|
Opnd0_ExpNum = Opnd0.drillAddendDownOneStep(Opnd0_0, Opnd0_1);
|
|
|
|
// Step 2: Expand the 2nd addend into Opnd1_0 and Opnd1_1.
|
|
if (OpndNum == 2 && !Opnd1.isConstant())
|
|
Opnd1_ExpNum = Opnd1.drillAddendDownOneStep(Opnd1_0, Opnd1_1);
|
|
|
|
// Step 3: Try to optimize Opnd0_0 + Opnd0_1 + Opnd1_0 + Opnd1_1
|
|
if (Opnd0_ExpNum && Opnd1_ExpNum) {
|
|
AddendVect AllOpnds;
|
|
AllOpnds.push_back(&Opnd0_0);
|
|
AllOpnds.push_back(&Opnd1_0);
|
|
if (Opnd0_ExpNum == 2)
|
|
AllOpnds.push_back(&Opnd0_1);
|
|
if (Opnd1_ExpNum == 2)
|
|
AllOpnds.push_back(&Opnd1_1);
|
|
|
|
// Compute instruction quota. We should save at least one instruction.
|
|
unsigned InstQuota = 0;
|
|
|
|
Value *V0 = I->getOperand(0);
|
|
Value *V1 = I->getOperand(1);
|
|
InstQuota = ((!isa<Constant>(V0) && V0->hasOneUse()) &&
|
|
(!isa<Constant>(V1) && V1->hasOneUse())) ? 2 : 1;
|
|
|
|
if (Value *R = simplifyFAdd(AllOpnds, InstQuota))
|
|
return R;
|
|
}
|
|
|
|
if (OpndNum != 2) {
|
|
// The input instruction is : "I=0.0 +/- V". If the "V" were able to be
|
|
// splitted into two addends, say "V = X - Y", the instruction would have
|
|
// been optimized into "I = Y - X" in the previous steps.
|
|
//
|
|
const FAddendCoef &CE = Opnd0.getCoef();
|
|
return CE.isOne() ? Opnd0.getSymVal() : 0;
|
|
}
|
|
|
|
// step 4: Try to optimize Opnd0 + Opnd1_0 [+ Opnd1_1]
|
|
if (Opnd1_ExpNum) {
|
|
AddendVect AllOpnds;
|
|
AllOpnds.push_back(&Opnd0);
|
|
AllOpnds.push_back(&Opnd1_0);
|
|
if (Opnd1_ExpNum == 2)
|
|
AllOpnds.push_back(&Opnd1_1);
|
|
|
|
if (Value *R = simplifyFAdd(AllOpnds, 1))
|
|
return R;
|
|
}
|
|
|
|
// step 5: Try to optimize Opnd1 + Opnd0_0 [+ Opnd0_1]
|
|
if (Opnd0_ExpNum) {
|
|
AddendVect AllOpnds;
|
|
AllOpnds.push_back(&Opnd1);
|
|
AllOpnds.push_back(&Opnd0_0);
|
|
if (Opnd0_ExpNum == 2)
|
|
AllOpnds.push_back(&Opnd0_1);
|
|
|
|
if (Value *R = simplifyFAdd(AllOpnds, 1))
|
|
return R;
|
|
}
|
|
|
|
// step 6: Try factorization as the last resort,
|
|
return performFactorization(I);
|
|
}
|
|
|
|
Value *FAddCombine::simplifyFAdd(AddendVect& Addends, unsigned InstrQuota) {
|
|
|
|
unsigned AddendNum = Addends.size();
|
|
assert(AddendNum <= 4 && "Too many addends");
|
|
|
|
// For saving intermediate results;
|
|
unsigned NextTmpIdx = 0;
|
|
FAddend TmpResult[3];
|
|
|
|
// Points to the constant addend of the resulting simplified expression.
|
|
// If the resulting expr has constant-addend, this constant-addend is
|
|
// desirable to reside at the top of the resulting expression tree. Placing
|
|
// constant close to supper-expr(s) will potentially reveal some optimization
|
|
// opportunities in super-expr(s).
|
|
//
|
|
const FAddend *ConstAdd = 0;
|
|
|
|
// Simplified addends are placed <SimpVect>.
|
|
AddendVect SimpVect;
|
|
|
|
// The outer loop works on one symbolic-value at a time. Suppose the input
|
|
// addends are : <a1, x>, <b1, y>, <a2, x>, <c1, z>, <b2, y>, ...
|
|
// The symbolic-values will be processed in this order: x, y, z.
|
|
//
|
|
for (unsigned SymIdx = 0; SymIdx < AddendNum; SymIdx++) {
|
|
|
|
const FAddend *ThisAddend = Addends[SymIdx];
|
|
if (!ThisAddend) {
|
|
// This addend was processed before.
|
|
continue;
|
|
}
|
|
|
|
Value *Val = ThisAddend->getSymVal();
|
|
unsigned StartIdx = SimpVect.size();
|
|
SimpVect.push_back(ThisAddend);
|
|
|
|
// The inner loop collects addends sharing same symbolic-value, and these
|
|
// addends will be later on folded into a single addend. Following above
|
|
// example, if the symbolic value "y" is being processed, the inner loop
|
|
// will collect two addends "<b1,y>" and "<b2,Y>". These two addends will
|
|
// be later on folded into "<b1+b2, y>".
|
|
//
|
|
for (unsigned SameSymIdx = SymIdx + 1;
|
|
SameSymIdx < AddendNum; SameSymIdx++) {
|
|
const FAddend *T = Addends[SameSymIdx];
|
|
if (T && T->getSymVal() == Val) {
|
|
// Set null such that next iteration of the outer loop will not process
|
|
// this addend again.
|
|
Addends[SameSymIdx] = 0;
|
|
SimpVect.push_back(T);
|
|
}
|
|
}
|
|
|
|
// If multiple addends share same symbolic value, fold them together.
|
|
if (StartIdx + 1 != SimpVect.size()) {
|
|
FAddend &R = TmpResult[NextTmpIdx ++];
|
|
R = *SimpVect[StartIdx];
|
|
for (unsigned Idx = StartIdx + 1; Idx < SimpVect.size(); Idx++)
|
|
R += *SimpVect[Idx];
|
|
|
|
// Pop all addends being folded and push the resulting folded addend.
|
|
SimpVect.resize(StartIdx);
|
|
if (Val != 0) {
|
|
if (!R.isZero()) {
|
|
SimpVect.push_back(&R);
|
|
}
|
|
} else {
|
|
// Don't push constant addend at this time. It will be the last element
|
|
// of <SimpVect>.
|
|
ConstAdd = &R;
|
|
}
|
|
}
|
|
}
|
|
|
|
assert((NextTmpIdx <= array_lengthof(TmpResult) + 1) &&
|
|
"out-of-bound access");
|
|
|
|
if (ConstAdd)
|
|
SimpVect.push_back(ConstAdd);
|
|
|
|
Value *Result;
|
|
if (!SimpVect.empty())
|
|
Result = createNaryFAdd(SimpVect, InstrQuota);
|
|
else {
|
|
// The addition is folded to 0.0.
|
|
Result = ConstantFP::get(Instr->getType(), 0.0);
|
|
}
|
|
|
|
return Result;
|
|
}
|
|
|
|
Value *FAddCombine::createNaryFAdd
|
|
(const AddendVect &Opnds, unsigned InstrQuota) {
|
|
assert(!Opnds.empty() && "Expect at least one addend");
|
|
|
|
// Step 1: Check if the # of instructions needed exceeds the quota.
|
|
//
|
|
unsigned InstrNeeded = calcInstrNumber(Opnds);
|
|
if (InstrNeeded > InstrQuota)
|
|
return 0;
|
|
|
|
initCreateInstNum();
|
|
|
|
// step 2: Emit the N-ary addition.
|
|
// Note that at most three instructions are involved in Fadd-InstCombine: the
|
|
// addition in question, and at most two neighboring instructions.
|
|
// The resulting optimized addition should have at least one less instruction
|
|
// than the original addition expression tree. This implies that the resulting
|
|
// N-ary addition has at most two instructions, and we don't need to worry
|
|
// about tree-height when constructing the N-ary addition.
|
|
|
|
Value *LastVal = 0;
|
|
bool LastValNeedNeg = false;
|
|
|
|
// Iterate the addends, creating fadd/fsub using adjacent two addends.
|
|
for (AddendVect::const_iterator I = Opnds.begin(), E = Opnds.end();
|
|
I != E; I++) {
|
|
bool NeedNeg;
|
|
Value *V = createAddendVal(**I, NeedNeg);
|
|
if (!LastVal) {
|
|
LastVal = V;
|
|
LastValNeedNeg = NeedNeg;
|
|
continue;
|
|
}
|
|
|
|
if (LastValNeedNeg == NeedNeg) {
|
|
LastVal = createFAdd(LastVal, V);
|
|
continue;
|
|
}
|
|
|
|
if (LastValNeedNeg)
|
|
LastVal = createFSub(V, LastVal);
|
|
else
|
|
LastVal = createFSub(LastVal, V);
|
|
|
|
LastValNeedNeg = false;
|
|
}
|
|
|
|
if (LastValNeedNeg) {
|
|
LastVal = createFNeg(LastVal);
|
|
}
|
|
|
|
#ifndef NDEBUG
|
|
assert(CreateInstrNum == InstrNeeded &&
|
|
"Inconsistent in instruction numbers");
|
|
#endif
|
|
|
|
return LastVal;
|
|
}
|
|
|
|
Value *FAddCombine::createFSub
|
|
(Value *Opnd0, Value *Opnd1) {
|
|
Value *V = Builder->CreateFSub(Opnd0, Opnd1);
|
|
if (Instruction *I = dyn_cast<Instruction>(V))
|
|
createInstPostProc(I);
|
|
return V;
|
|
}
|
|
|
|
Value *FAddCombine::createFNeg(Value *V) {
|
|
Value *Zero = cast<Value>(ConstantFP::get(V->getType(), 0.0));
|
|
Value *NewV = createFSub(Zero, V);
|
|
if (Instruction *I = dyn_cast<Instruction>(NewV))
|
|
createInstPostProc(I, true); // fneg's don't receive instruction numbers.
|
|
return NewV;
|
|
}
|
|
|
|
Value *FAddCombine::createFAdd
|
|
(Value *Opnd0, Value *Opnd1) {
|
|
Value *V = Builder->CreateFAdd(Opnd0, Opnd1);
|
|
if (Instruction *I = dyn_cast<Instruction>(V))
|
|
createInstPostProc(I);
|
|
return V;
|
|
}
|
|
|
|
Value *FAddCombine::createFMul(Value *Opnd0, Value *Opnd1) {
|
|
Value *V = Builder->CreateFMul(Opnd0, Opnd1);
|
|
if (Instruction *I = dyn_cast<Instruction>(V))
|
|
createInstPostProc(I);
|
|
return V;
|
|
}
|
|
|
|
Value *FAddCombine::createFDiv(Value *Opnd0, Value *Opnd1) {
|
|
Value *V = Builder->CreateFDiv(Opnd0, Opnd1);
|
|
if (Instruction *I = dyn_cast<Instruction>(V))
|
|
createInstPostProc(I);
|
|
return V;
|
|
}
|
|
|
|
void FAddCombine::createInstPostProc(Instruction *NewInstr,
|
|
bool NoNumber) {
|
|
NewInstr->setDebugLoc(Instr->getDebugLoc());
|
|
|
|
// Keep track of the number of instruction created.
|
|
if (!NoNumber)
|
|
incCreateInstNum();
|
|
|
|
// Propagate fast-math flags
|
|
NewInstr->setFastMathFlags(Instr->getFastMathFlags());
|
|
}
|
|
|
|
// Return the number of instruction needed to emit the N-ary addition.
|
|
// NOTE: Keep this function in sync with createAddendVal().
|
|
unsigned FAddCombine::calcInstrNumber(const AddendVect &Opnds) {
|
|
unsigned OpndNum = Opnds.size();
|
|
unsigned InstrNeeded = OpndNum - 1;
|
|
|
|
// The number of addends in the form of "(-1)*x".
|
|
unsigned NegOpndNum = 0;
|
|
|
|
// Adjust the number of instructions needed to emit the N-ary add.
|
|
for (AddendVect::const_iterator I = Opnds.begin(), E = Opnds.end();
|
|
I != E; I++) {
|
|
const FAddend *Opnd = *I;
|
|
if (Opnd->isConstant())
|
|
continue;
|
|
|
|
const FAddendCoef &CE = Opnd->getCoef();
|
|
if (CE.isMinusOne() || CE.isMinusTwo())
|
|
NegOpndNum++;
|
|
|
|
// Let the addend be "c * x". If "c == +/-1", the value of the addend
|
|
// is immediately available; otherwise, it needs exactly one instruction
|
|
// to evaluate the value.
|
|
if (!CE.isMinusOne() && !CE.isOne())
|
|
InstrNeeded++;
|
|
}
|
|
if (NegOpndNum == OpndNum)
|
|
InstrNeeded++;
|
|
return InstrNeeded;
|
|
}
|
|
|
|
// Input Addend Value NeedNeg(output)
|
|
// ================================================================
|
|
// Constant C C false
|
|
// <+/-1, V> V coefficient is -1
|
|
// <2/-2, V> "fadd V, V" coefficient is -2
|
|
// <C, V> "fmul V, C" false
|
|
//
|
|
// NOTE: Keep this function in sync with FAddCombine::calcInstrNumber.
|
|
Value *FAddCombine::createAddendVal
|
|
(const FAddend &Opnd, bool &NeedNeg) {
|
|
const FAddendCoef &Coeff = Opnd.getCoef();
|
|
|
|
if (Opnd.isConstant()) {
|
|
NeedNeg = false;
|
|
return Coeff.getValue(Instr->getType());
|
|
}
|
|
|
|
Value *OpndVal = Opnd.getSymVal();
|
|
|
|
if (Coeff.isMinusOne() || Coeff.isOne()) {
|
|
NeedNeg = Coeff.isMinusOne();
|
|
return OpndVal;
|
|
}
|
|
|
|
if (Coeff.isTwo() || Coeff.isMinusTwo()) {
|
|
NeedNeg = Coeff.isMinusTwo();
|
|
return createFAdd(OpndVal, OpndVal);
|
|
}
|
|
|
|
NeedNeg = false;
|
|
return createFMul(OpndVal, Coeff.getValue(Instr->getType()));
|
|
}
|
|
|
|
// dyn_castFoldableMul - If this value is a multiply that can be folded into
|
|
// other computations (because it has a constant operand), return the
|
|
// non-constant operand of the multiply, and set CST to point to the multiplier.
|
|
// Otherwise, return null.
|
|
//
|
|
static inline Value *dyn_castFoldableMul(Value *V, Constant *&CST) {
|
|
if (!V->hasOneUse() || !V->getType()->isIntOrIntVectorTy())
|
|
return 0;
|
|
|
|
Instruction *I = dyn_cast<Instruction>(V);
|
|
if (I == 0) return 0;
|
|
|
|
if (I->getOpcode() == Instruction::Mul)
|
|
if ((CST = dyn_cast<Constant>(I->getOperand(1))))
|
|
return I->getOperand(0);
|
|
if (I->getOpcode() == Instruction::Shl)
|
|
if ((CST = dyn_cast<Constant>(I->getOperand(1)))) {
|
|
// The multiplier is really 1 << CST.
|
|
CST = ConstantExpr::getShl(ConstantInt::get(V->getType(), 1), CST);
|
|
return I->getOperand(0);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
|
|
/// WillNotOverflowSignedAdd - Return true if we can prove that:
|
|
/// (sext (add LHS, RHS)) === (add (sext LHS), (sext RHS))
|
|
/// This basically requires proving that the add in the original type would not
|
|
/// overflow to change the sign bit or have a carry out.
|
|
bool InstCombiner::WillNotOverflowSignedAdd(Value *LHS, Value *RHS) {
|
|
// There are different heuristics we can use for this. Here are some simple
|
|
// ones.
|
|
|
|
// Add has the property that adding any two 2's complement numbers can only
|
|
// have one carry bit which can change a sign. As such, if LHS and RHS each
|
|
// have at least two sign bits, we know that the addition of the two values
|
|
// will sign extend fine.
|
|
if (ComputeNumSignBits(LHS) > 1 && ComputeNumSignBits(RHS) > 1)
|
|
return true;
|
|
|
|
|
|
// If one of the operands only has one non-zero bit, and if the other operand
|
|
// has a known-zero bit in a more significant place than it (not including the
|
|
// sign bit) the ripple may go up to and fill the zero, but won't change the
|
|
// sign. For example, (X & ~4) + 1.
|
|
|
|
// TODO: Implement.
|
|
|
|
return false;
|
|
}
|
|
|
|
Instruction *InstCombiner::visitAdd(BinaryOperator &I) {
|
|
bool Changed = SimplifyAssociativeOrCommutative(I);
|
|
Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
|
|
|
|
if (Value *V = SimplifyAddInst(LHS, RHS, I.hasNoSignedWrap(),
|
|
I.hasNoUnsignedWrap(), TD))
|
|
return ReplaceInstUsesWith(I, V);
|
|
|
|
// (A*B)+(A*C) -> A*(B+C) etc
|
|
if (Value *V = SimplifyUsingDistributiveLaws(I))
|
|
return ReplaceInstUsesWith(I, V);
|
|
|
|
if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
|
|
// X + (signbit) --> X ^ signbit
|
|
const APInt &Val = CI->getValue();
|
|
if (Val.isSignBit())
|
|
return BinaryOperator::CreateXor(LHS, RHS);
|
|
|
|
// See if SimplifyDemandedBits can simplify this. This handles stuff like
|
|
// (X & 254)+1 -> (X&254)|1
|
|
if (SimplifyDemandedInstructionBits(I))
|
|
return &I;
|
|
|
|
// zext(bool) + C -> bool ? C + 1 : C
|
|
if (ZExtInst *ZI = dyn_cast<ZExtInst>(LHS))
|
|
if (ZI->getSrcTy()->isIntegerTy(1))
|
|
return SelectInst::Create(ZI->getOperand(0), AddOne(CI), CI);
|
|
|
|
Value *XorLHS = 0; ConstantInt *XorRHS = 0;
|
|
if (match(LHS, m_Xor(m_Value(XorLHS), m_ConstantInt(XorRHS)))) {
|
|
uint32_t TySizeBits = I.getType()->getScalarSizeInBits();
|
|
const APInt &RHSVal = CI->getValue();
|
|
unsigned ExtendAmt = 0;
|
|
// If we have ADD(XOR(AND(X, 0xFF), 0x80), 0xF..F80), it's a sext.
|
|
// If we have ADD(XOR(AND(X, 0xFF), 0xF..F80), 0x80), it's a sext.
|
|
if (XorRHS->getValue() == -RHSVal) {
|
|
if (RHSVal.isPowerOf2())
|
|
ExtendAmt = TySizeBits - RHSVal.logBase2() - 1;
|
|
else if (XorRHS->getValue().isPowerOf2())
|
|
ExtendAmt = TySizeBits - XorRHS->getValue().logBase2() - 1;
|
|
}
|
|
|
|
if (ExtendAmt) {
|
|
APInt Mask = APInt::getHighBitsSet(TySizeBits, ExtendAmt);
|
|
if (!MaskedValueIsZero(XorLHS, Mask))
|
|
ExtendAmt = 0;
|
|
}
|
|
|
|
if (ExtendAmt) {
|
|
Constant *ShAmt = ConstantInt::get(I.getType(), ExtendAmt);
|
|
Value *NewShl = Builder->CreateShl(XorLHS, ShAmt, "sext");
|
|
return BinaryOperator::CreateAShr(NewShl, ShAmt);
|
|
}
|
|
|
|
// If this is a xor that was canonicalized from a sub, turn it back into
|
|
// a sub and fuse this add with it.
|
|
if (LHS->hasOneUse() && (XorRHS->getValue()+1).isPowerOf2()) {
|
|
IntegerType *IT = cast<IntegerType>(I.getType());
|
|
APInt LHSKnownOne(IT->getBitWidth(), 0);
|
|
APInt LHSKnownZero(IT->getBitWidth(), 0);
|
|
ComputeMaskedBits(XorLHS, LHSKnownZero, LHSKnownOne);
|
|
if ((XorRHS->getValue() | LHSKnownZero).isAllOnesValue())
|
|
return BinaryOperator::CreateSub(ConstantExpr::getAdd(XorRHS, CI),
|
|
XorLHS);
|
|
}
|
|
// (X + signbit) + C could have gotten canonicalized to (X ^ signbit) + C,
|
|
// transform them into (X + (signbit ^ C))
|
|
if (XorRHS->getValue().isSignBit())
|
|
return BinaryOperator::CreateAdd(XorLHS,
|
|
ConstantExpr::getXor(XorRHS, CI));
|
|
}
|
|
}
|
|
|
|
if (isa<Constant>(RHS) && isa<PHINode>(LHS))
|
|
if (Instruction *NV = FoldOpIntoPhi(I))
|
|
return NV;
|
|
|
|
if (I.getType()->getScalarType()->isIntegerTy(1))
|
|
return BinaryOperator::CreateXor(LHS, RHS);
|
|
|
|
// X + X --> X << 1
|
|
if (LHS == RHS) {
|
|
BinaryOperator *New =
|
|
BinaryOperator::CreateShl(LHS, ConstantInt::get(I.getType(), 1));
|
|
New->setHasNoSignedWrap(I.hasNoSignedWrap());
|
|
New->setHasNoUnsignedWrap(I.hasNoUnsignedWrap());
|
|
return New;
|
|
}
|
|
|
|
// -A + B --> B - A
|
|
// -A + -B --> -(A + B)
|
|
if (Value *LHSV = dyn_castNegVal(LHS)) {
|
|
if (!isa<Constant>(RHS))
|
|
if (Value *RHSV = dyn_castNegVal(RHS)) {
|
|
Value *NewAdd = Builder->CreateAdd(LHSV, RHSV, "sum");
|
|
return BinaryOperator::CreateNeg(NewAdd);
|
|
}
|
|
|
|
return BinaryOperator::CreateSub(RHS, LHSV);
|
|
}
|
|
|
|
// A + -B --> A - B
|
|
if (!isa<Constant>(RHS))
|
|
if (Value *V = dyn_castNegVal(RHS))
|
|
return BinaryOperator::CreateSub(LHS, V);
|
|
|
|
|
|
{
|
|
Constant *C2;
|
|
if (Value *X = dyn_castFoldableMul(LHS, C2)) {
|
|
if (X == RHS) // X*C + X --> X * (C+1)
|
|
return BinaryOperator::CreateMul(RHS, AddOne(C2));
|
|
|
|
// X*C1 + X*C2 --> X * (C1+C2)
|
|
Constant *C1;
|
|
if (X == dyn_castFoldableMul(RHS, C1))
|
|
return BinaryOperator::CreateMul(X, ConstantExpr::getAdd(C1, C2));
|
|
}
|
|
|
|
// X + X*C --> X * (C+1)
|
|
if (dyn_castFoldableMul(RHS, C2) == LHS)
|
|
return BinaryOperator::CreateMul(LHS, AddOne(C2));
|
|
}
|
|
|
|
// A+B --> A|B iff A and B have no bits set in common.
|
|
if (IntegerType *IT = dyn_cast<IntegerType>(I.getType())) {
|
|
APInt LHSKnownOne(IT->getBitWidth(), 0);
|
|
APInt LHSKnownZero(IT->getBitWidth(), 0);
|
|
ComputeMaskedBits(LHS, LHSKnownZero, LHSKnownOne);
|
|
if (LHSKnownZero != 0) {
|
|
APInt RHSKnownOne(IT->getBitWidth(), 0);
|
|
APInt RHSKnownZero(IT->getBitWidth(), 0);
|
|
ComputeMaskedBits(RHS, RHSKnownZero, RHSKnownOne);
|
|
|
|
// No bits in common -> bitwise or.
|
|
if ((LHSKnownZero|RHSKnownZero).isAllOnesValue())
|
|
return BinaryOperator::CreateOr(LHS, RHS);
|
|
}
|
|
}
|
|
|
|
// W*X + Y*Z --> W * (X+Z) iff W == Y
|
|
{
|
|
Value *W, *X, *Y, *Z;
|
|
if (match(LHS, m_Mul(m_Value(W), m_Value(X))) &&
|
|
match(RHS, m_Mul(m_Value(Y), m_Value(Z)))) {
|
|
if (W != Y) {
|
|
if (W == Z) {
|
|
std::swap(Y, Z);
|
|
} else if (Y == X) {
|
|
std::swap(W, X);
|
|
} else if (X == Z) {
|
|
std::swap(Y, Z);
|
|
std::swap(W, X);
|
|
}
|
|
}
|
|
|
|
if (W == Y) {
|
|
Value *NewAdd = Builder->CreateAdd(X, Z, LHS->getName());
|
|
return BinaryOperator::CreateMul(W, NewAdd);
|
|
}
|
|
}
|
|
}
|
|
|
|
if (Constant *CRHS = dyn_cast<Constant>(RHS)) {
|
|
Value *X;
|
|
if (match(LHS, m_Not(m_Value(X)))) // ~X + C --> (C-1) - X
|
|
return BinaryOperator::CreateSub(SubOne(CRHS), X);
|
|
}
|
|
|
|
if (ConstantInt *CRHS = dyn_cast<ConstantInt>(RHS)) {
|
|
// (X & FF00) + xx00 -> (X+xx00) & FF00
|
|
Value *X;
|
|
ConstantInt *C2;
|
|
if (LHS->hasOneUse() &&
|
|
match(LHS, m_And(m_Value(X), m_ConstantInt(C2))) &&
|
|
CRHS->getValue() == (CRHS->getValue() & C2->getValue())) {
|
|
// See if all bits from the first bit set in the Add RHS up are included
|
|
// in the mask. First, get the rightmost bit.
|
|
const APInt &AddRHSV = CRHS->getValue();
|
|
|
|
// Form a mask of all bits from the lowest bit added through the top.
|
|
APInt AddRHSHighBits(~((AddRHSV & -AddRHSV)-1));
|
|
|
|
// See if the and mask includes all of these bits.
|
|
APInt AddRHSHighBitsAnd(AddRHSHighBits & C2->getValue());
|
|
|
|
if (AddRHSHighBits == AddRHSHighBitsAnd) {
|
|
// Okay, the xform is safe. Insert the new add pronto.
|
|
Value *NewAdd = Builder->CreateAdd(X, CRHS, LHS->getName());
|
|
return BinaryOperator::CreateAnd(NewAdd, C2);
|
|
}
|
|
}
|
|
|
|
// Try to fold constant add into select arguments.
|
|
if (SelectInst *SI = dyn_cast<SelectInst>(LHS))
|
|
if (Instruction *R = FoldOpIntoSelect(I, SI))
|
|
return R;
|
|
}
|
|
|
|
// add (select X 0 (sub n A)) A --> select X A n
|
|
{
|
|
SelectInst *SI = dyn_cast<SelectInst>(LHS);
|
|
Value *A = RHS;
|
|
if (!SI) {
|
|
SI = dyn_cast<SelectInst>(RHS);
|
|
A = LHS;
|
|
}
|
|
if (SI && SI->hasOneUse()) {
|
|
Value *TV = SI->getTrueValue();
|
|
Value *FV = SI->getFalseValue();
|
|
Value *N;
|
|
|
|
// Can we fold the add into the argument of the select?
|
|
// We check both true and false select arguments for a matching subtract.
|
|
if (match(FV, m_Zero()) && match(TV, m_Sub(m_Value(N), m_Specific(A))))
|
|
// Fold the add into the true select value.
|
|
return SelectInst::Create(SI->getCondition(), N, A);
|
|
|
|
if (match(TV, m_Zero()) && match(FV, m_Sub(m_Value(N), m_Specific(A))))
|
|
// Fold the add into the false select value.
|
|
return SelectInst::Create(SI->getCondition(), A, N);
|
|
}
|
|
}
|
|
|
|
// Check for (add (sext x), y), see if we can merge this into an
|
|
// integer add followed by a sext.
|
|
if (SExtInst *LHSConv = dyn_cast<SExtInst>(LHS)) {
|
|
// (add (sext x), cst) --> (sext (add x, cst'))
|
|
if (ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS)) {
|
|
Constant *CI =
|
|
ConstantExpr::getTrunc(RHSC, LHSConv->getOperand(0)->getType());
|
|
if (LHSConv->hasOneUse() &&
|
|
ConstantExpr::getSExt(CI, I.getType()) == RHSC &&
|
|
WillNotOverflowSignedAdd(LHSConv->getOperand(0), CI)) {
|
|
// Insert the new, smaller add.
|
|
Value *NewAdd = Builder->CreateNSWAdd(LHSConv->getOperand(0),
|
|
CI, "addconv");
|
|
return new SExtInst(NewAdd, I.getType());
|
|
}
|
|
}
|
|
|
|
// (add (sext x), (sext y)) --> (sext (add int x, y))
|
|
if (SExtInst *RHSConv = dyn_cast<SExtInst>(RHS)) {
|
|
// Only do this if x/y have the same type, if at last one of them has a
|
|
// single use (so we don't increase the number of sexts), and if the
|
|
// integer add will not overflow.
|
|
if (LHSConv->getOperand(0)->getType()==RHSConv->getOperand(0)->getType()&&
|
|
(LHSConv->hasOneUse() || RHSConv->hasOneUse()) &&
|
|
WillNotOverflowSignedAdd(LHSConv->getOperand(0),
|
|
RHSConv->getOperand(0))) {
|
|
// Insert the new integer add.
|
|
Value *NewAdd = Builder->CreateNSWAdd(LHSConv->getOperand(0),
|
|
RHSConv->getOperand(0), "addconv");
|
|
return new SExtInst(NewAdd, I.getType());
|
|
}
|
|
}
|
|
}
|
|
|
|
// Check for (x & y) + (x ^ y)
|
|
{
|
|
Value *A = 0, *B = 0;
|
|
if (match(RHS, m_Xor(m_Value(A), m_Value(B))) &&
|
|
(match(LHS, m_And(m_Specific(A), m_Specific(B))) ||
|
|
match(LHS, m_And(m_Specific(B), m_Specific(A)))))
|
|
return BinaryOperator::CreateOr(A, B);
|
|
|
|
if (match(LHS, m_Xor(m_Value(A), m_Value(B))) &&
|
|
(match(RHS, m_And(m_Specific(A), m_Specific(B))) ||
|
|
match(RHS, m_And(m_Specific(B), m_Specific(A)))))
|
|
return BinaryOperator::CreateOr(A, B);
|
|
}
|
|
|
|
return Changed ? &I : 0;
|
|
}
|
|
|
|
Instruction *InstCombiner::visitFAdd(BinaryOperator &I) {
|
|
bool Changed = SimplifyAssociativeOrCommutative(I);
|
|
Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
|
|
|
|
if (Value *V = SimplifyFAddInst(LHS, RHS, I.getFastMathFlags(), TD))
|
|
return ReplaceInstUsesWith(I, V);
|
|
|
|
if (isa<Constant>(RHS)) {
|
|
if (isa<PHINode>(LHS))
|
|
if (Instruction *NV = FoldOpIntoPhi(I))
|
|
return NV;
|
|
|
|
if (SelectInst *SI = dyn_cast<SelectInst>(LHS))
|
|
if (Instruction *NV = FoldOpIntoSelect(I, SI))
|
|
return NV;
|
|
}
|
|
|
|
// -A + B --> B - A
|
|
// -A + -B --> -(A + B)
|
|
if (Value *LHSV = dyn_castFNegVal(LHS)) {
|
|
Instruction *RI = BinaryOperator::CreateFSub(RHS, LHSV);
|
|
RI->copyFastMathFlags(&I);
|
|
return RI;
|
|
}
|
|
|
|
// A + -B --> A - B
|
|
if (!isa<Constant>(RHS))
|
|
if (Value *V = dyn_castFNegVal(RHS)) {
|
|
Instruction *RI = BinaryOperator::CreateFSub(LHS, V);
|
|
RI->copyFastMathFlags(&I);
|
|
return RI;
|
|
}
|
|
|
|
// Check for (fadd double (sitofp x), y), see if we can merge this into an
|
|
// integer add followed by a promotion.
|
|
if (SIToFPInst *LHSConv = dyn_cast<SIToFPInst>(LHS)) {
|
|
// (fadd double (sitofp x), fpcst) --> (sitofp (add int x, intcst))
|
|
// ... if the constant fits in the integer value. This is useful for things
|
|
// like (double)(x & 1234) + 4.0 -> (double)((X & 1234)+4) which no longer
|
|
// requires a constant pool load, and generally allows the add to be better
|
|
// instcombined.
|
|
if (ConstantFP *CFP = dyn_cast<ConstantFP>(RHS)) {
|
|
Constant *CI =
|
|
ConstantExpr::getFPToSI(CFP, LHSConv->getOperand(0)->getType());
|
|
if (LHSConv->hasOneUse() &&
|
|
ConstantExpr::getSIToFP(CI, I.getType()) == CFP &&
|
|
WillNotOverflowSignedAdd(LHSConv->getOperand(0), CI)) {
|
|
// Insert the new integer add.
|
|
Value *NewAdd = Builder->CreateNSWAdd(LHSConv->getOperand(0),
|
|
CI, "addconv");
|
|
return new SIToFPInst(NewAdd, I.getType());
|
|
}
|
|
}
|
|
|
|
// (fadd double (sitofp x), (sitofp y)) --> (sitofp (add int x, y))
|
|
if (SIToFPInst *RHSConv = dyn_cast<SIToFPInst>(RHS)) {
|
|
// Only do this if x/y have the same type, if at last one of them has a
|
|
// single use (so we don't increase the number of int->fp conversions),
|
|
// and if the integer add will not overflow.
|
|
if (LHSConv->getOperand(0)->getType()==RHSConv->getOperand(0)->getType()&&
|
|
(LHSConv->hasOneUse() || RHSConv->hasOneUse()) &&
|
|
WillNotOverflowSignedAdd(LHSConv->getOperand(0),
|
|
RHSConv->getOperand(0))) {
|
|
// Insert the new integer add.
|
|
Value *NewAdd = Builder->CreateNSWAdd(LHSConv->getOperand(0),
|
|
RHSConv->getOperand(0),"addconv");
|
|
return new SIToFPInst(NewAdd, I.getType());
|
|
}
|
|
}
|
|
}
|
|
|
|
// select C, 0, B + select C, A, 0 -> select C, A, B
|
|
{
|
|
Value *A1, *B1, *C1, *A2, *B2, *C2;
|
|
if (match(LHS, m_Select(m_Value(C1), m_Value(A1), m_Value(B1))) &&
|
|
match(RHS, m_Select(m_Value(C2), m_Value(A2), m_Value(B2)))) {
|
|
if (C1 == C2) {
|
|
Constant *Z1=0, *Z2=0;
|
|
Value *A, *B, *C=C1;
|
|
if (match(A1, m_AnyZero()) && match(B2, m_AnyZero())) {
|
|
Z1 = dyn_cast<Constant>(A1); A = A2;
|
|
Z2 = dyn_cast<Constant>(B2); B = B1;
|
|
} else if (match(B1, m_AnyZero()) && match(A2, m_AnyZero())) {
|
|
Z1 = dyn_cast<Constant>(B1); B = B2;
|
|
Z2 = dyn_cast<Constant>(A2); A = A1;
|
|
}
|
|
|
|
if (Z1 && Z2 &&
|
|
(I.hasNoSignedZeros() ||
|
|
(Z1->isNegativeZeroValue() && Z2->isNegativeZeroValue()))) {
|
|
return SelectInst::Create(C, A, B);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if (I.hasUnsafeAlgebra()) {
|
|
if (Value *V = FAddCombine(Builder).simplify(&I))
|
|
return ReplaceInstUsesWith(I, V);
|
|
}
|
|
|
|
return Changed ? &I : 0;
|
|
}
|
|
|
|
|
|
/// Optimize pointer differences into the same array into a size. Consider:
|
|
/// &A[10] - &A[0]: we should compile this to "10". LHS/RHS are the pointer
|
|
/// operands to the ptrtoint instructions for the LHS/RHS of the subtract.
|
|
///
|
|
Value *InstCombiner::OptimizePointerDifference(Value *LHS, Value *RHS,
|
|
Type *Ty) {
|
|
assert(TD && "Must have target data info for this");
|
|
|
|
// If LHS is a gep based on RHS or RHS is a gep based on LHS, we can optimize
|
|
// this.
|
|
bool Swapped = false;
|
|
GEPOperator *GEP1 = 0, *GEP2 = 0;
|
|
|
|
// For now we require one side to be the base pointer "A" or a constant
|
|
// GEP derived from it.
|
|
if (GEPOperator *LHSGEP = dyn_cast<GEPOperator>(LHS)) {
|
|
// (gep X, ...) - X
|
|
if (LHSGEP->getOperand(0) == RHS) {
|
|
GEP1 = LHSGEP;
|
|
Swapped = false;
|
|
} else if (GEPOperator *RHSGEP = dyn_cast<GEPOperator>(RHS)) {
|
|
// (gep X, ...) - (gep X, ...)
|
|
if (LHSGEP->getOperand(0)->stripPointerCasts() ==
|
|
RHSGEP->getOperand(0)->stripPointerCasts()) {
|
|
GEP2 = RHSGEP;
|
|
GEP1 = LHSGEP;
|
|
Swapped = false;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (GEPOperator *RHSGEP = dyn_cast<GEPOperator>(RHS)) {
|
|
// X - (gep X, ...)
|
|
if (RHSGEP->getOperand(0) == LHS) {
|
|
GEP1 = RHSGEP;
|
|
Swapped = true;
|
|
} else if (GEPOperator *LHSGEP = dyn_cast<GEPOperator>(LHS)) {
|
|
// (gep X, ...) - (gep X, ...)
|
|
if (RHSGEP->getOperand(0)->stripPointerCasts() ==
|
|
LHSGEP->getOperand(0)->stripPointerCasts()) {
|
|
GEP2 = LHSGEP;
|
|
GEP1 = RHSGEP;
|
|
Swapped = true;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Avoid duplicating the arithmetic if GEP2 has non-constant indices and
|
|
// multiple users.
|
|
if (GEP1 == 0 ||
|
|
(GEP2 != 0 && !GEP2->hasAllConstantIndices() && !GEP2->hasOneUse()))
|
|
return 0;
|
|
|
|
// Emit the offset of the GEP and an intptr_t.
|
|
Value *Result = EmitGEPOffset(GEP1);
|
|
|
|
// If we had a constant expression GEP on the other side offsetting the
|
|
// pointer, subtract it from the offset we have.
|
|
if (GEP2) {
|
|
Value *Offset = EmitGEPOffset(GEP2);
|
|
Result = Builder->CreateSub(Result, Offset);
|
|
}
|
|
|
|
// If we have p - gep(p, ...) then we have to negate the result.
|
|
if (Swapped)
|
|
Result = Builder->CreateNeg(Result, "diff.neg");
|
|
|
|
return Builder->CreateIntCast(Result, Ty, true);
|
|
}
|
|
|
|
|
|
Instruction *InstCombiner::visitSub(BinaryOperator &I) {
|
|
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
|
|
|
|
if (Value *V = SimplifySubInst(Op0, Op1, I.hasNoSignedWrap(),
|
|
I.hasNoUnsignedWrap(), TD))
|
|
return ReplaceInstUsesWith(I, V);
|
|
|
|
// (A*B)-(A*C) -> A*(B-C) etc
|
|
if (Value *V = SimplifyUsingDistributiveLaws(I))
|
|
return ReplaceInstUsesWith(I, V);
|
|
|
|
// If this is a 'B = x-(-A)', change to B = x+A. This preserves NSW/NUW.
|
|
if (Value *V = dyn_castNegVal(Op1)) {
|
|
BinaryOperator *Res = BinaryOperator::CreateAdd(Op0, V);
|
|
Res->setHasNoSignedWrap(I.hasNoSignedWrap());
|
|
Res->setHasNoUnsignedWrap(I.hasNoUnsignedWrap());
|
|
return Res;
|
|
}
|
|
|
|
if (I.getType()->isIntegerTy(1))
|
|
return BinaryOperator::CreateXor(Op0, Op1);
|
|
|
|
// Replace (-1 - A) with (~A).
|
|
if (match(Op0, m_AllOnes()))
|
|
return BinaryOperator::CreateNot(Op1);
|
|
|
|
if (Constant *C = dyn_cast<Constant>(Op0)) {
|
|
// C - ~X == X + (1+C)
|
|
Value *X = 0;
|
|
if (match(Op1, m_Not(m_Value(X))))
|
|
return BinaryOperator::CreateAdd(X, AddOne(C));
|
|
|
|
// Try to fold constant sub into select arguments.
|
|
if (SelectInst *SI = dyn_cast<SelectInst>(Op1))
|
|
if (Instruction *R = FoldOpIntoSelect(I, SI))
|
|
return R;
|
|
|
|
// C-(X+C2) --> (C-C2)-X
|
|
Constant *C2;
|
|
if (match(Op1, m_Add(m_Value(X), m_Constant(C2))))
|
|
return BinaryOperator::CreateSub(ConstantExpr::getSub(C, C2), X);
|
|
|
|
if (SimplifyDemandedInstructionBits(I))
|
|
return &I;
|
|
|
|
// Fold (sub 0, (zext bool to B)) --> (sext bool to B)
|
|
if (C->isNullValue() && match(Op1, m_ZExt(m_Value(X))))
|
|
if (X->getType()->getScalarType()->isIntegerTy(1))
|
|
return CastInst::CreateSExtOrBitCast(X, Op1->getType());
|
|
|
|
// Fold (sub 0, (sext bool to B)) --> (zext bool to B)
|
|
if (C->isNullValue() && match(Op1, m_SExt(m_Value(X))))
|
|
if (X->getType()->getScalarType()->isIntegerTy(1))
|
|
return CastInst::CreateZExtOrBitCast(X, Op1->getType());
|
|
}
|
|
|
|
if (ConstantInt *C = dyn_cast<ConstantInt>(Op0)) {
|
|
// -(X >>u 31) -> (X >>s 31)
|
|
// -(X >>s 31) -> (X >>u 31)
|
|
if (C->isZero()) {
|
|
Value *X; ConstantInt *CI;
|
|
if (match(Op1, m_LShr(m_Value(X), m_ConstantInt(CI))) &&
|
|
// Verify we are shifting out everything but the sign bit.
|
|
CI->getValue() == I.getType()->getPrimitiveSizeInBits()-1)
|
|
return BinaryOperator::CreateAShr(X, CI);
|
|
|
|
if (match(Op1, m_AShr(m_Value(X), m_ConstantInt(CI))) &&
|
|
// Verify we are shifting out everything but the sign bit.
|
|
CI->getValue() == I.getType()->getPrimitiveSizeInBits()-1)
|
|
return BinaryOperator::CreateLShr(X, CI);
|
|
}
|
|
}
|
|
|
|
|
|
{ Value *Y;
|
|
// X-(X+Y) == -Y X-(Y+X) == -Y
|
|
if (match(Op1, m_Add(m_Specific(Op0), m_Value(Y))) ||
|
|
match(Op1, m_Add(m_Value(Y), m_Specific(Op0))))
|
|
return BinaryOperator::CreateNeg(Y);
|
|
|
|
// (X-Y)-X == -Y
|
|
if (match(Op0, m_Sub(m_Specific(Op1), m_Value(Y))))
|
|
return BinaryOperator::CreateNeg(Y);
|
|
}
|
|
|
|
if (Op1->hasOneUse()) {
|
|
Value *X = 0, *Y = 0, *Z = 0;
|
|
Constant *C = 0;
|
|
Constant *CI = 0;
|
|
|
|
// (X - (Y - Z)) --> (X + (Z - Y)).
|
|
if (match(Op1, m_Sub(m_Value(Y), m_Value(Z))))
|
|
return BinaryOperator::CreateAdd(Op0,
|
|
Builder->CreateSub(Z, Y, Op1->getName()));
|
|
|
|
// (X - (X & Y)) --> (X & ~Y)
|
|
//
|
|
if (match(Op1, m_And(m_Value(Y), m_Specific(Op0))) ||
|
|
match(Op1, m_And(m_Specific(Op0), m_Value(Y))))
|
|
return BinaryOperator::CreateAnd(Op0,
|
|
Builder->CreateNot(Y, Y->getName() + ".not"));
|
|
|
|
// 0 - (X sdiv C) -> (X sdiv -C)
|
|
if (match(Op1, m_SDiv(m_Value(X), m_Constant(C))) &&
|
|
match(Op0, m_Zero()))
|
|
return BinaryOperator::CreateSDiv(X, ConstantExpr::getNeg(C));
|
|
|
|
// 0 - (X << Y) -> (-X << Y) when X is freely negatable.
|
|
if (match(Op1, m_Shl(m_Value(X), m_Value(Y))) && match(Op0, m_Zero()))
|
|
if (Value *XNeg = dyn_castNegVal(X))
|
|
return BinaryOperator::CreateShl(XNeg, Y);
|
|
|
|
// X - X*C --> X * (1-C)
|
|
if (match(Op1, m_Mul(m_Specific(Op0), m_Constant(CI)))) {
|
|
Constant *CP1 = ConstantExpr::getSub(ConstantInt::get(I.getType(),1), CI);
|
|
return BinaryOperator::CreateMul(Op0, CP1);
|
|
}
|
|
|
|
// X - X<<C --> X * (1-(1<<C))
|
|
if (match(Op1, m_Shl(m_Specific(Op0), m_Constant(CI)))) {
|
|
Constant *One = ConstantInt::get(I.getType(), 1);
|
|
C = ConstantExpr::getSub(One, ConstantExpr::getShl(One, CI));
|
|
return BinaryOperator::CreateMul(Op0, C);
|
|
}
|
|
|
|
// X - A*-B -> X + A*B
|
|
// X - -A*B -> X + A*B
|
|
Value *A, *B;
|
|
if (match(Op1, m_Mul(m_Value(A), m_Neg(m_Value(B)))) ||
|
|
match(Op1, m_Mul(m_Neg(m_Value(A)), m_Value(B))))
|
|
return BinaryOperator::CreateAdd(Op0, Builder->CreateMul(A, B));
|
|
|
|
// X - A*CI -> X + A*-CI
|
|
// X - CI*A -> X + A*-CI
|
|
if (match(Op1, m_Mul(m_Value(A), m_Constant(CI))) ||
|
|
match(Op1, m_Mul(m_Constant(CI), m_Value(A)))) {
|
|
Value *NewMul = Builder->CreateMul(A, ConstantExpr::getNeg(CI));
|
|
return BinaryOperator::CreateAdd(Op0, NewMul);
|
|
}
|
|
}
|
|
|
|
Constant *C1;
|
|
if (Value *X = dyn_castFoldableMul(Op0, C1)) {
|
|
if (X == Op1) // X*C - X --> X * (C-1)
|
|
return BinaryOperator::CreateMul(Op1, SubOne(C1));
|
|
|
|
Constant *C2; // X*C1 - X*C2 -> X * (C1-C2)
|
|
if (X == dyn_castFoldableMul(Op1, C2))
|
|
return BinaryOperator::CreateMul(X, ConstantExpr::getSub(C1, C2));
|
|
}
|
|
|
|
// Optimize pointer differences into the same array into a size. Consider:
|
|
// &A[10] - &A[0]: we should compile this to "10".
|
|
if (TD) {
|
|
Value *LHSOp, *RHSOp;
|
|
if (match(Op0, m_PtrToInt(m_Value(LHSOp))) &&
|
|
match(Op1, m_PtrToInt(m_Value(RHSOp))))
|
|
if (Value *Res = OptimizePointerDifference(LHSOp, RHSOp, I.getType()))
|
|
return ReplaceInstUsesWith(I, Res);
|
|
|
|
// trunc(p)-trunc(q) -> trunc(p-q)
|
|
if (match(Op0, m_Trunc(m_PtrToInt(m_Value(LHSOp)))) &&
|
|
match(Op1, m_Trunc(m_PtrToInt(m_Value(RHSOp)))))
|
|
if (Value *Res = OptimizePointerDifference(LHSOp, RHSOp, I.getType()))
|
|
return ReplaceInstUsesWith(I, Res);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
Instruction *InstCombiner::visitFSub(BinaryOperator &I) {
|
|
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
|
|
|
|
if (Value *V = SimplifyFSubInst(Op0, Op1, I.getFastMathFlags(), TD))
|
|
return ReplaceInstUsesWith(I, V);
|
|
|
|
if (isa<Constant>(Op0))
|
|
if (SelectInst *SI = dyn_cast<SelectInst>(Op1))
|
|
if (Instruction *NV = FoldOpIntoSelect(I, SI))
|
|
return NV;
|
|
|
|
// If this is a 'B = x-(-A)', change to B = x+A, potentially looking
|
|
// through FP extensions/truncations along the way.
|
|
if (Value *V = dyn_castFNegVal(Op1)) {
|
|
Instruction *NewI = BinaryOperator::CreateFAdd(Op0, V);
|
|
NewI->copyFastMathFlags(&I);
|
|
return NewI;
|
|
}
|
|
if (FPTruncInst *FPTI = dyn_cast<FPTruncInst>(Op1)) {
|
|
if (Value *V = dyn_castFNegVal(FPTI->getOperand(0))) {
|
|
Value *NewTrunc = Builder->CreateFPTrunc(V, I.getType());
|
|
Instruction *NewI = BinaryOperator::CreateFAdd(Op0, NewTrunc);
|
|
NewI->copyFastMathFlags(&I);
|
|
return NewI;
|
|
}
|
|
} else if (FPExtInst *FPEI = dyn_cast<FPExtInst>(Op1)) {
|
|
if (Value *V = dyn_castFNegVal(FPEI->getOperand(0))) {
|
|
Value *NewExt = Builder->CreateFPExt(V, I.getType());
|
|
Instruction *NewI = BinaryOperator::CreateFAdd(Op0, NewExt);
|
|
NewI->copyFastMathFlags(&I);
|
|
return NewI;
|
|
}
|
|
}
|
|
|
|
if (I.hasUnsafeAlgebra()) {
|
|
if (Value *V = FAddCombine(Builder).simplify(&I))
|
|
return ReplaceInstUsesWith(I, V);
|
|
}
|
|
|
|
return 0;
|
|
}
|