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rdar://12801297
InstCombine for unsafe floating-point add/sub. llvm-svn: 170471
This commit is contained in:
Shuxin Yang
parent
e44a431d35
commit
712da2e5c6
@ -19,10 +19,715 @@
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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[0]); }
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const APFloat &getFpVal(void) const {
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assert(IsFp && BufHasFpVal && "Incorret state");
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return *reinterpret_cast<const APFloat*>(&FpValBuf[0]);
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}
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APFloat &getFpVal(void)
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{ assert(IsFp && BufHasFpVal && "Incorret state"); return *getFpValPtr(); }
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bool isInt() const { return !IsFp; }
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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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union {
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char FpValBuf[sizeof(APFloat)];
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int dummy; // So this structure has at least 4-byte alignment.
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};
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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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/// 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 *createFNeg(Value *V);
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Value *createNaryFAdd(const AddendVect& Opnds, unsigned InstrQuota);
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void createInstPostProc(Instruction *NewInst);
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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::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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set(T);
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getFpVal().add(APFloat(T.getSemantics(), IntVal), RndMode);
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return;
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}
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APFloat &T = getFpVal();
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T.add(APFloat(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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set(T);
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getFpVal().subtract(APFloat(T.getSemantics(), IntVal), RndMode);
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return;
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}
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APFloat &T = getFpVal();
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T.subtract(APFloat(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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set(APFloat(Semantic, IntVal));
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APFloat &F0 = getFpVal();
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if (That.isInt())
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F0.multiply(APFloat(Semantic, That.IntVal), 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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Value *FAddCombine::simplify(Instruction *I) {
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assert(I->hasUnsafeAlgebra() && "Should be in unsafe mode");
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// Currently we are not able to handle vector type.
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if (I->getType()->isVectorTy())
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return 0;
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assert((I->getOpcode() == Instruction::FAdd ||
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I->getOpcode() == Instruction::FSub) && "Expect add/sub");
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// Save the instruction before calling other member-functions.
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Instr = I;
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FAddend Opnd0, Opnd1, Opnd0_0, Opnd0_1, Opnd1_0, Opnd1_1;
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unsigned OpndNum = FAddend::drillValueDownOneStep(I, Opnd0, Opnd1);
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// Step 1: Expand the 1st addend into Opnd0_0 and Opnd0_1.
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unsigned Opnd0_ExpNum = 0;
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unsigned Opnd1_ExpNum = 0;
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if (!Opnd0.isConstant())
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Opnd0_ExpNum = Opnd0.drillAddendDownOneStep(Opnd0_0, Opnd0_1);
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// Step 2: Expand the 2nd addend into Opnd1_0 and Opnd1_1.
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if (OpndNum == 2 && !Opnd1.isConstant())
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Opnd1_ExpNum = Opnd1.drillAddendDownOneStep(Opnd1_0, Opnd1_1);
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// Step 3: Try to optimize Opnd0_0 + Opnd0_1 + Opnd1_0 + Opnd1_1
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if (Opnd0_ExpNum && Opnd1_ExpNum) {
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AddendVect AllOpnds;
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AllOpnds.push_back(&Opnd0_0);
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AllOpnds.push_back(&Opnd1_0);
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if (Opnd0_ExpNum == 2)
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AllOpnds.push_back(&Opnd0_1);
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if (Opnd1_ExpNum == 2)
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AllOpnds.push_back(&Opnd1_1);
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// Compute instruction quota. We should save at least one instruction.
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unsigned InstQuota = 0;
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Value *V0 = I->getOperand(0);
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Value *V1 = I->getOperand(1);
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InstQuota = ((!isa<Constant>(V0) && V0->hasOneUse()) &&
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(!isa<Constant>(V1) && V1->hasOneUse())) ? 2 : 1;
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if (Value *R = simplifyFAdd(AllOpnds, InstQuota))
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return R;
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}
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if (OpndNum != 2) {
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// The input instruction is : "I=0.0 +/- V". If the "V" were able to be
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// splitted into two addends, say "V = X - Y", the instruction would have
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// been optimized into "I = Y - X" in the previous steps.
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//
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const FAddendCoef &CE = Opnd0.getCoef();
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return CE.isOne() ? Opnd0.getSymVal() : 0;
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}
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// step 4: Try to optimize Opnd0 + Opnd1_0 [+ Opnd1_1]
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if (Opnd1_ExpNum) {
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AddendVect AllOpnds;
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AllOpnds.push_back(&Opnd0);
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AllOpnds.push_back(&Opnd1_0);
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if (Opnd1_ExpNum == 2)
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AllOpnds.push_back(&Opnd1_1);
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if (Value *R = simplifyFAdd(AllOpnds, 1))
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return R;
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}
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// step 5: Try to optimize Opnd1 + Opnd0_0 [+ Opnd0_1]
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if (Opnd0_ExpNum) {
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AddendVect AllOpnds;
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AllOpnds.push_back(&Opnd1);
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AllOpnds.push_back(&Opnd0_0);
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if (Opnd0_ExpNum == 2)
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AllOpnds.push_back(&Opnd0_1);
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if (Value *R = simplifyFAdd(AllOpnds, 1))
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return R;
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}
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return 0;
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}
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Value *FAddCombine::simplifyFAdd(AddendVect& Addends, unsigned InstrQuota) {
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unsigned AddendNum = Addends.size();
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assert(AddendNum <= 4 && "Too many addends");
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// For saving intermediate results;
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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 <= sizeof(TmpResult)/sizeof(TmpResult[0]) + 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);
|
||||
createInstPostProc(cast<Instruction>(V));
|
||||
return V;
|
||||
}
|
||||
|
||||
Value *FAddCombine::createFNeg(Value *V) {
|
||||
Value *Zero = cast<Value>(ConstantFP::get(V->getType(), 0.0));
|
||||
return createFSub(Zero, V);
|
||||
}
|
||||
|
||||
Value *FAddCombine::createFAdd
|
||||
(Value *Opnd0, Value *Opnd1) {
|
||||
Value *V = Builder->CreateFAdd(Opnd0, Opnd1);
|
||||
createInstPostProc(cast<Instruction>(V));
|
||||
return V;
|
||||
}
|
||||
|
||||
Value *FAddCombine::createFMul(Value *Opnd0, Value *Opnd1) {
|
||||
Value *V = Builder->CreateFMul(Opnd0, Opnd1);
|
||||
createInstPostProc(cast<Instruction>(V));
|
||||
return V;
|
||||
}
|
||||
|
||||
void FAddCombine::createInstPostProc(Instruction *NewInstr) {
|
||||
NewInstr->setDebugLoc(Instr->getDebugLoc());
|
||||
|
||||
// Keep track of the number of instruction created.
|
||||
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()));
|
||||
}
|
||||
|
||||
/// AddOne - Add one to a ConstantInt.
|
||||
static Constant *AddOne(Constant *C) {
|
||||
return ConstantExpr::getAdd(C, ConstantInt::get(C->getType(), 1));
|
||||
}
|
||||
|
||||
/// SubOne - Subtract one from a ConstantInt.
|
||||
static Constant *SubOne(ConstantInt *C) {
|
||||
return ConstantInt::get(C->getContext(), C->getValue()-1);
|
||||
@ -406,6 +1111,11 @@ Instruction *InstCombiner::visitFAdd(BinaryOperator &I) {
|
||||
}
|
||||
}
|
||||
|
||||
if (I.hasUnsafeAlgebra()) {
|
||||
if (Value *V = FAddCombine(Builder).simplify(&I))
|
||||
return ReplaceInstUsesWith(I, V);
|
||||
}
|
||||
|
||||
return Changed ? &I : 0;
|
||||
}
|
||||
|
||||
@ -649,5 +1359,10 @@ Instruction *InstCombiner::visitFSub(BinaryOperator &I) {
|
||||
if (Value *V = dyn_castFNegVal(Op1))
|
||||
return BinaryOperator::CreateFAdd(Op0, V);
|
||||
|
||||
if (I.hasUnsafeAlgebra()) {
|
||||
if (Value *V = FAddCombine(Builder).simplify(&I))
|
||||
return ReplaceInstUsesWith(I, V);
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
@ -28,6 +28,108 @@ define float @fold2(float %a) {
|
||||
ret float %mul1
|
||||
}
|
||||
|
||||
; C * f1 + f1 = (C+1) * f1
|
||||
define double @fold3(double %f1) {
|
||||
%t1 = fmul fast double 2.000000e+00, %f1
|
||||
%t2 = fadd fast double %f1, %t1
|
||||
ret double %t2
|
||||
; CHECK: @fold3
|
||||
; CHECK: fmul fast double %f1, 3.000000e+00
|
||||
}
|
||||
|
||||
; (C1 - X) + (C2 - Y) => (C1+C2) - (X + Y)
|
||||
define float @fold4(float %f1, float %f2) {
|
||||
%sub = fsub float 4.000000e+00, %f1
|
||||
%sub1 = fsub float 5.000000e+00, %f2
|
||||
%add = fadd fast float %sub, %sub1
|
||||
ret float %add
|
||||
; CHECK: @fold4
|
||||
; CHECK: %1 = fadd fast float %f1, %f2
|
||||
; CHECK: fsub fast float 9.000000e+00, %1
|
||||
}
|
||||
|
||||
; (X + C1) + C2 => X + (C1 + C2)
|
||||
define float @fold5(float %f1, float %f2) {
|
||||
%add = fadd float %f1, 4.000000e+00
|
||||
%add1 = fadd fast float %add, 5.000000e+00
|
||||
ret float %add1
|
||||
; CHECK: @fold5
|
||||
; CHECK: fadd float %f1, 9.000000e+00
|
||||
}
|
||||
|
||||
; (X + X) + X => 3.0 * X
|
||||
define float @fold6(float %f1) {
|
||||
%t1 = fadd fast float %f1, %f1
|
||||
%t2 = fadd fast float %f1, %t1
|
||||
ret float %t2
|
||||
; CHECK: @fold6
|
||||
; CHECK: fmul fast float %f1, 3.000000e+00
|
||||
}
|
||||
|
||||
; C1 * X + (X + X) = (C1 + 2) * X
|
||||
define float @fold7(float %f1) {
|
||||
%t1 = fmul fast float %f1, 5.000000e+00
|
||||
%t2 = fadd fast float %f1, %f1
|
||||
%t3 = fadd fast float %t1, %t2
|
||||
ret float %t3
|
||||
; CHECK: @fold7
|
||||
; CHECK: fmul fast float %f1, 7.000000e+00
|
||||
}
|
||||
|
||||
; (X + X) + (X + X) => 4.0 * X
|
||||
define float @fold8(float %f1) {
|
||||
%t1 = fadd fast float %f1, %f1
|
||||
%t2 = fadd fast float %f1, %f1
|
||||
%t3 = fadd fast float %t1, %t2
|
||||
ret float %t3
|
||||
; CHECK: fold8
|
||||
; CHECK: fmul fast float %f1, 4.000000e+00
|
||||
}
|
||||
|
||||
; X - (X + Y) => 0 - Y
|
||||
define float @fold9(float %f1, float %f2) {
|
||||
%t1 = fadd float %f1, %f2
|
||||
%t3 = fsub fast float %f1, %t1
|
||||
ret float %t3
|
||||
|
||||
; CHECK: @fold9
|
||||
; CHECK: fsub fast float 0.000000e+00, %f2
|
||||
}
|
||||
|
||||
; Let C3 = C1 + C2. (f1 + C1) + (f2 + C2) => (f1 + f2) + C3 instead of
|
||||
; "(f1 + C3) + f2" or "(f2 + C3) + f1". Placing constant-addend at the
|
||||
; top of resulting simplified expression tree may potentially reveal some
|
||||
; optimization opportunities in the super-expression trees.
|
||||
;
|
||||
define float @fold10(float %f1, float %f2) {
|
||||
%t1 = fadd fast float 2.000000e+00, %f1
|
||||
%t2 = fsub fast float %f2, 3.000000e+00
|
||||
%t3 = fadd fast float %t1, %t2
|
||||
ret float %t3
|
||||
; CHECK: @fold10
|
||||
; CHECK: %t3 = fadd float %t2, -1.000000e+00
|
||||
; CHECK: ret float %t3
|
||||
}
|
||||
|
||||
; once cause Crash/miscompilation
|
||||
define float @fail1(float %f1, float %f2) {
|
||||
%conv3 = fadd fast float %f1, -1.000000e+00
|
||||
%add = fadd fast float %conv3, %conv3
|
||||
%add2 = fadd fast float %add, %conv3
|
||||
ret float %add2
|
||||
; CHECK: @fail1
|
||||
; CHECK: ret
|
||||
}
|
||||
|
||||
define double @fail2(double %f1, double %f2) {
|
||||
%t1 = fsub fast double %f1, %f2
|
||||
%t2 = fadd fast double %f1, %f2
|
||||
%t3 = fsub fast double %t1, %t2
|
||||
ret double %t3
|
||||
; CHECK: @fail2
|
||||
; CHECK: ret
|
||||
}
|
||||
|
||||
; rdar://12753946: x * cond ? 1.0 : 0.0 => cond ? x : 0.0
|
||||
define double @select1(i32 %cond, double %x, double %y) {
|
||||
%tobool = icmp ne i32 %cond, 0
|
||||
|
||||
Loading…
Reference in New Issue
Block a user