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Eliminate all of the SCEV Expansion code which is really part of the
IndVars pass, not part of SCEV *analysis*. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13134 91177308-0d34-0410-b5e6-96231b3b80d8
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@ -33,10 +33,6 @@
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// higher-level code, such as the code that recognizes PHI nodes of various
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// types, computes the execution count of a loop, etc.
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//
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// Orthogonal to the analysis of code above, this file also implements the
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// ScalarEvolutionRewriter class, which is used to emit code that represents the
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// various recurrences present in a loop, in canonical forms.
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//
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// TODO: We should use these routines and value representations to implement
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// dependence analysis!
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//
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@ -160,13 +156,6 @@ bool SCEVCouldNotCompute::hasComputableLoopEvolution(const Loop *L) const {
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return false;
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}
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Value *SCEVCouldNotCompute::expandCodeFor(ScalarEvolutionRewriter &SER,
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Instruction *InsertPt) {
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assert(0 && "Attempt to use a SCEVCouldNotCompute object!");
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return 0;
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}
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void SCEVCouldNotCompute::print(std::ostream &OS) const {
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OS << "***COULDNOTCOMPUTE***";
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}
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@ -358,7 +347,7 @@ void SCEVUnknown::print(std::ostream &OS) const {
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/// getIntegerSCEV - Given an integer or FP type, create a constant for the
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/// specified signed integer value and return a SCEV for the constant.
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static SCEVHandle getIntegerSCEV(int Val, const Type *Ty) {
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SCEVHandle SCEVUnknown::getIntegerSCEV(int Val, const Type *Ty) {
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Constant *C;
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if (Val == 0)
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C = Constant::getNullValue(Ty);
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@ -393,7 +382,7 @@ static SCEVHandle getNegativeSCEV(const SCEVHandle &V) {
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if (SCEVConstant *VC = dyn_cast<SCEVConstant>(V))
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return SCEVUnknown::get(ConstantExpr::getNeg(VC->getValue()));
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return SCEVMulExpr::get(V, getIntegerSCEV(-1, V->getType()));
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return SCEVMulExpr::get(V, SCEVUnknown::getIntegerSCEV(-1, V->getType()));
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}
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/// getMinusSCEV - Return a SCEV corresponding to LHS - RHS.
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@ -438,11 +427,12 @@ static SCEVHandle PartialFact(SCEVHandle V, unsigned NumSteps) {
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const Type *Ty = V->getType();
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if (NumSteps == 0)
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return getIntegerSCEV(1, Ty);
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return SCEVUnknown::getIntegerSCEV(1, Ty);
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SCEVHandle Result = V;
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for (unsigned i = 1; i != NumSteps; ++i)
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Result = SCEVMulExpr::get(Result, getMinusSCEV(V, getIntegerSCEV(i, Ty)));
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Result = SCEVMulExpr::get(Result, getMinusSCEV(V,
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SCEVUnknown::getIntegerSCEV(i, Ty)));
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return Result;
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}
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@ -465,7 +455,7 @@ SCEVHandle SCEVAddRecExpr::evaluateAtIteration(SCEVHandle It) const {
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SCEVHandle BC = PartialFact(It, i);
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Divisor *= i;
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SCEVHandle Val = SCEVUDivExpr::get(SCEVMulExpr::get(BC, getOperand(i)),
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getIntegerSCEV(Divisor, Ty));
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SCEVUnknown::getIntegerSCEV(Divisor,Ty));
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Result = SCEVAddExpr::get(Result, Val);
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}
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return Result;
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@ -558,7 +548,7 @@ SCEVHandle SCEVAddExpr::get(std::vector<SCEVHandle> &Ops) {
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if (Ops[i] == Ops[i+1]) { // X + Y + Y --> X + Y*2
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// Found a match, merge the two values into a multiply, and add any
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// remaining values to the result.
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SCEVHandle Two = getIntegerSCEV(2, Ty);
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SCEVHandle Two = SCEVUnknown::getIntegerSCEV(2, Ty);
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SCEVHandle Mul = SCEVMulExpr::get(Ops[i], Two);
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if (Ops.size() == 2)
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return Mul;
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@ -609,7 +599,7 @@ SCEVHandle SCEVAddExpr::get(std::vector<SCEVHandle> &Ops) {
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MulOps.erase(MulOps.begin()+MulOp);
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InnerMul = SCEVMulExpr::get(MulOps);
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}
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SCEVHandle One = getIntegerSCEV(1, Ty);
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SCEVHandle One = SCEVUnknown::getIntegerSCEV(1, Ty);
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SCEVHandle AddOne = SCEVAddExpr::get(InnerMul, One);
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SCEVHandle OuterMul = SCEVMulExpr::get(AddOne, Ops[AddOp]);
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if (Ops.size() == 2) return OuterMul;
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@ -976,137 +966,6 @@ SCEVHandle SCEVUnknown::get(Value *V) {
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}
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//===----------------------------------------------------------------------===//
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// Non-trivial closed-form SCEV Expanders
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//===----------------------------------------------------------------------===//
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Value *SCEVTruncateExpr::expandCodeFor(ScalarEvolutionRewriter &SER,
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Instruction *InsertPt) {
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Value *V = SER.ExpandCodeFor(getOperand(), InsertPt);
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return new CastInst(V, getType(), "tmp.", InsertPt);
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}
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Value *SCEVZeroExtendExpr::expandCodeFor(ScalarEvolutionRewriter &SER,
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Instruction *InsertPt) {
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Value *V = SER.ExpandCodeFor(getOperand(), InsertPt,
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getOperand()->getType()->getUnsignedVersion());
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return new CastInst(V, getType(), "tmp.", InsertPt);
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}
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Value *SCEVAddExpr::expandCodeFor(ScalarEvolutionRewriter &SER,
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Instruction *InsertPt) {
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const Type *Ty = getType();
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Value *V = SER.ExpandCodeFor(getOperand(getNumOperands()-1), InsertPt, Ty);
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// Emit a bunch of add instructions
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for (int i = getNumOperands()-2; i >= 0; --i)
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V = BinaryOperator::create(Instruction::Add, V,
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SER.ExpandCodeFor(getOperand(i), InsertPt, Ty),
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"tmp.", InsertPt);
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return V;
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}
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Value *SCEVMulExpr::expandCodeFor(ScalarEvolutionRewriter &SER,
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Instruction *InsertPt) {
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const Type *Ty = getType();
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int FirstOp = 0; // Set if we should emit a subtract.
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if (SCEVConstant *SC = dyn_cast<SCEVConstant>(getOperand(0)))
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if (SC->getValue()->isAllOnesValue())
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FirstOp = 1;
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int i = getNumOperands()-2;
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Value *V = SER.ExpandCodeFor(getOperand(i+1), InsertPt, Ty);
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// Emit a bunch of multiply instructions
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for (; i >= FirstOp; --i)
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V = BinaryOperator::create(Instruction::Mul, V,
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SER.ExpandCodeFor(getOperand(i), InsertPt, Ty),
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"tmp.", InsertPt);
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// -1 * ... ---> 0 - ...
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if (FirstOp == 1)
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V = BinaryOperator::create(Instruction::Sub, Constant::getNullValue(Ty), V,
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"tmp.", InsertPt);
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return V;
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}
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Value *SCEVUDivExpr::expandCodeFor(ScalarEvolutionRewriter &SER,
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Instruction *InsertPt) {
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const Type *Ty = getType();
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Value *LHS = SER.ExpandCodeFor(getLHS(), InsertPt, Ty);
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Value *RHS = SER.ExpandCodeFor(getRHS(), InsertPt, Ty);
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return BinaryOperator::create(Instruction::Div, LHS, RHS, "tmp.", InsertPt);
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}
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Value *SCEVAddRecExpr::expandCodeFor(ScalarEvolutionRewriter &SER,
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Instruction *InsertPt) {
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const Type *Ty = getType();
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// We cannot yet do fp recurrences, e.g. the xform of {X,+,F} --> X+{0,+,F}
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assert(Ty->isIntegral() && "Cannot expand fp recurrences yet!");
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// {X,+,F} --> X + {0,+,F}
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if (!isa<SCEVConstant>(getStart()) ||
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!cast<SCEVConstant>(getStart())->getValue()->isNullValue()) {
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Value *Start = SER.ExpandCodeFor(getStart(), InsertPt, Ty);
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std::vector<SCEVHandle> NewOps(op_begin(), op_end());
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NewOps[0] = getIntegerSCEV(0, getType());
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Value *Rest = SER.ExpandCodeFor(SCEVAddRecExpr::get(NewOps, getLoop()),
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InsertPt, getType());
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// FIXME: look for an existing add to use.
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return BinaryOperator::create(Instruction::Add, Rest, Start, "tmp.",
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InsertPt);
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}
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// {0,+,1} --> Insert a canonical induction variable into the loop!
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if (getNumOperands() == 2 && getOperand(1) == getIntegerSCEV(1, getType())) {
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// Create and insert the PHI node for the induction variable in the
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// specified loop.
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BasicBlock *Header = getLoop()->getHeader();
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PHINode *PN = new PHINode(Ty, "indvar", Header->begin());
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PN->addIncoming(Constant::getNullValue(Ty), L->getLoopPreheader());
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pred_iterator HPI = pred_begin(Header);
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assert(HPI != pred_end(Header) && "Loop with zero preds???");
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if (!getLoop()->contains(*HPI)) ++HPI;
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assert(HPI != pred_end(Header) && getLoop()->contains(*HPI) &&
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"No backedge in loop?");
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// Insert a unit add instruction right before the terminator corresponding
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// to the back-edge.
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Constant *One = Ty->isFloatingPoint() ? (Constant*)ConstantFP::get(Ty, 1.0)
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: (Constant*)ConstantInt::get(Ty, 1);
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Instruction *Add = BinaryOperator::create(Instruction::Add, PN, One,
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"indvar.next",
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(*HPI)->getTerminator());
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pred_iterator PI = pred_begin(Header);
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if (*PI == L->getLoopPreheader())
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++PI;
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PN->addIncoming(Add, *PI);
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return PN;
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}
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// Get the canonical induction variable I for this loop.
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Value *I = SER.GetOrInsertCanonicalInductionVariable(getLoop(), Ty);
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if (getNumOperands() == 2) { // {0,+,F} --> i*F
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Value *F = SER.ExpandCodeFor(getOperand(1), InsertPt, Ty);
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return BinaryOperator::create(Instruction::Mul, I, F, "tmp.", InsertPt);
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}
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// If this is a chain of recurrences, turn it into a closed form, using the
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// folders, then expandCodeFor the closed form. This allows the folders to
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// simplify the expression without having to build a bunch of special code
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// into this folder.
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SCEVHandle IH = SCEVUnknown::get(I); // Get I as a "symbolic" SCEV.
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SCEVHandle V = evaluateAtIteration(IH);
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//std::cerr << "Evaluated: " << *this << "\n to: " << *V << "\n";
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return SER.ExpandCodeFor(V, InsertPt, Ty);
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}
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//===----------------------------------------------------------------------===//
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// ScalarEvolutionsImpl Definition and Implementation
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//===----------------------------------------------------------------------===//
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@ -2099,7 +1958,7 @@ SCEVHandle SCEVAddRecExpr::getNumIterationsInRange(ConstantRange Range) const {
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if (SCEVConstant *SC = dyn_cast<SCEVConstant>(getStart()))
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if (!SC->getValue()->isNullValue()) {
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std::vector<SCEVHandle> Operands(op_begin(), op_end());
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Operands[0] = getIntegerSCEV(0, SC->getType());
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Operands[0] = SCEVUnknown::getIntegerSCEV(0, SC->getType());
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SCEVHandle Shifted = SCEVAddRecExpr::get(Operands, getLoop());
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if (SCEVAddRecExpr *ShiftedAddRec = dyn_cast<SCEVAddRecExpr>(Shifted))
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return ShiftedAddRec->getNumIterationsInRange(
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@ -2348,66 +2207,3 @@ void ScalarEvolution::print(std::ostream &OS) const {
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PrintLoopInfo(OS, this, *I);
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}
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//===----------------------------------------------------------------------===//
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// ScalarEvolutionRewriter Class Implementation
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//===----------------------------------------------------------------------===//
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Value *ScalarEvolutionRewriter::
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GetOrInsertCanonicalInductionVariable(const Loop *L, const Type *Ty) {
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assert((Ty->isInteger() || Ty->isFloatingPoint()) &&
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"Can only insert integer or floating point induction variables!");
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// Check to see if we already inserted one.
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SCEVHandle H = SCEVAddRecExpr::get(getIntegerSCEV(0, Ty),
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getIntegerSCEV(1, Ty), L);
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return ExpandCodeFor(H, 0, Ty);
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}
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/// ExpandCodeFor - Insert code to directly compute the specified SCEV
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/// expression into the program. The inserted code is inserted into the
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/// specified block.
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Value *ScalarEvolutionRewriter::ExpandCodeFor(SCEVHandle SH,
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Instruction *InsertPt,
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const Type *Ty) {
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std::map<SCEVHandle, Value*>::iterator ExistVal =InsertedExpressions.find(SH);
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Value *V;
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if (ExistVal != InsertedExpressions.end()) {
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V = ExistVal->second;
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} else {
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// Ask the recurrence object to expand the code for itself.
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V = SH->expandCodeFor(*this, InsertPt);
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// Cache the generated result.
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InsertedExpressions.insert(std::make_pair(SH, V));
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}
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if (Ty == 0 || V->getType() == Ty)
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return V;
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if (Constant *C = dyn_cast<Constant>(V))
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return ConstantExpr::getCast(C, Ty);
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else if (Instruction *I = dyn_cast<Instruction>(V)) {
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// Check to see if there is already a cast. If there is, use it.
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for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
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UI != E; ++UI) {
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if ((*UI)->getType() == Ty)
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if (CastInst *CI = dyn_cast<CastInst>(cast<Instruction>(*UI))) {
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BasicBlock::iterator It = I; ++It;
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while (isa<PHINode>(It)) ++It;
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if (It != BasicBlock::iterator(CI)) {
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// Splice the cast immediately after the operand in question.
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I->getParent()->getInstList().splice(It,
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CI->getParent()->getInstList(),
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CI);
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}
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return CI;
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}
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}
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BasicBlock::iterator IP = I; ++IP;
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if (InvokeInst *II = dyn_cast<InvokeInst>(I))
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IP = II->getNormalDest()->begin();
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while (isa<PHINode>(IP)) ++IP;
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return new CastInst(V, Ty, V->getName(), IP);
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} else {
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// FIXME: check to see if there is already a cast!
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return new CastInst(V, Ty, V->getName(), InsertPt);
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}
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}
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