//
// The LLVM Compiler Infrastructure
//
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//
//===----------------------------------------------------------------------===//
-#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/ScalarEvolutionExpander.h"
+#include "llvm/Analysis/LoopInfo.h"
using namespace llvm;
/// InsertCastOfTo - Insert a cast of V to the specified type, doing what
/// we can to share the casts.
-Value *SCEVExpander::InsertCastOfTo(Value *V, const Type *Ty) {
+Value *SCEVExpander::InsertCastOfTo(Instruction::CastOps opcode, Value *V,
+ const Type *Ty) {
// FIXME: keep track of the cast instruction.
if (Constant *C = dyn_cast<Constant>(V))
- return ConstantExpr::getCast(C, Ty);
+ return ConstantExpr::getCast(opcode, C, Ty);
if (Argument *A = dyn_cast<Argument>(V)) {
// Check to see if there is already a cast!
for (Value::use_iterator UI = A->use_begin(), E = A->use_end();
UI != E; ++UI) {
if ((*UI)->getType() == Ty)
- if (CastInst *CI = dyn_cast<CastInst>(cast<Instruction>(*UI))) {
- // If the cast isn't the first instruction of the function, move it.
- if (BasicBlock::iterator(CI) !=
- A->getParent()->getEntryBlock().begin()) {
- CI->moveBefore(A->getParent()->getEntryBlock().begin());
+ if (CastInst *CI = dyn_cast<CastInst>(cast<Instruction>(*UI)))
+ if (CI->getOpcode() == opcode) {
+ // If the cast isn't the first instruction of the function, move it.
+ if (BasicBlock::iterator(CI) !=
+ A->getParent()->getEntryBlock().begin()) {
+ CI->moveBefore(A->getParent()->getEntryBlock().begin());
+ }
+ return CI;
}
- return CI;
- }
}
- return CastInst::createInferredCast(V, Ty, V->getName(),
- A->getParent()->getEntryBlock().begin());
+ return CastInst::Create(opcode, V, Ty, V->getName(),
+ A->getParent()->getEntryBlock().begin());
}
-
+
Instruction *I = cast<Instruction>(V);
-
+
// Check to see if there is already a cast. If there is, use it.
for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
UI != E; ++UI) {
if ((*UI)->getType() == Ty)
- if (CastInst *CI = dyn_cast<CastInst>(cast<Instruction>(*UI))) {
- BasicBlock::iterator It = I; ++It;
- if (isa<InvokeInst>(I))
- It = cast<InvokeInst>(I)->getNormalDest()->begin();
- while (isa<PHINode>(It)) ++It;
- if (It != BasicBlock::iterator(CI)) {
- // Splice the cast immediately after the operand in question.
- CI->moveBefore(It);
+ if (CastInst *CI = dyn_cast<CastInst>(cast<Instruction>(*UI)))
+ if (CI->getOpcode() == opcode) {
+ BasicBlock::iterator It = I; ++It;
+ if (isa<InvokeInst>(I))
+ It = cast<InvokeInst>(I)->getNormalDest()->begin();
+ while (isa<PHINode>(It)) ++It;
+ if (It != BasicBlock::iterator(CI)) {
+ // Splice the cast immediately after the operand in question.
+ CI->moveBefore(It);
+ }
+ return CI;
}
- return CI;
- }
}
BasicBlock::iterator IP = I; ++IP;
if (InvokeInst *II = dyn_cast<InvokeInst>(I))
IP = II->getNormalDest()->begin();
while (isa<PHINode>(IP)) ++IP;
- return CastInst::createInferredCast(V, Ty, V->getName(), IP);
+ return CastInst::Create(opcode, V, Ty, V->getName(), IP);
+}
+
+/// InsertBinop - Insert the specified binary operator, doing a small amount
+/// of work to avoid inserting an obviously redundant operation.
+Value *SCEVExpander::InsertBinop(Instruction::BinaryOps Opcode, Value *LHS,
+ Value *RHS, Instruction *InsertPt) {
+ // Fold a binop with constant operands.
+ if (Constant *CLHS = dyn_cast<Constant>(LHS))
+ if (Constant *CRHS = dyn_cast<Constant>(RHS))
+ return ConstantExpr::get(Opcode, CLHS, CRHS);
+
+ // Do a quick scan to see if we have this binop nearby. If so, reuse it.
+ unsigned ScanLimit = 6;
+ BasicBlock::iterator BlockBegin = InsertPt->getParent()->begin();
+ if (InsertPt != BlockBegin) {
+ // Scanning starts from the last instruction before InsertPt.
+ BasicBlock::iterator IP = InsertPt;
+ --IP;
+ for (; ScanLimit; --IP, --ScanLimit) {
+ if (BinaryOperator *BinOp = dyn_cast<BinaryOperator>(IP))
+ if (BinOp->getOpcode() == Opcode && BinOp->getOperand(0) == LHS &&
+ BinOp->getOperand(1) == RHS)
+ return BinOp;
+ if (IP == BlockBegin) break;
+ }
+ }
+
+ // If we haven't found this binop, insert it.
+ return BinaryOperator::Create(Opcode, LHS, RHS, "tmp", InsertPt);
}
+Value *SCEVExpander::visitAddExpr(SCEVAddExpr *S) {
+ Value *V = expand(S->getOperand(S->getNumOperands()-1));
+
+ // Emit a bunch of add instructions
+ for (int i = S->getNumOperands()-2; i >= 0; --i)
+ V = InsertBinop(Instruction::Add, V, expand(S->getOperand(i)),
+ InsertPt);
+ return V;
+}
+
Value *SCEVExpander::visitMulExpr(SCEVMulExpr *S) {
- const Type *Ty = S->getType();
int FirstOp = 0; // Set if we should emit a subtract.
if (SCEVConstant *SC = dyn_cast<SCEVConstant>(S->getOperand(0)))
if (SC->getValue()->isAllOnesValue())
FirstOp = 1;
int i = S->getNumOperands()-2;
- Value *V = expandInTy(S->getOperand(i+1), Ty);
+ Value *V = expand(S->getOperand(i+1));
// Emit a bunch of multiply instructions
for (; i >= FirstOp; --i)
- V = BinaryOperator::createMul(V, expandInTy(S->getOperand(i), Ty),
- "tmp.", InsertPt);
+ V = InsertBinop(Instruction::Mul, V, expand(S->getOperand(i)),
+ InsertPt);
// -1 * ... ---> 0 - ...
if (FirstOp == 1)
- V = BinaryOperator::createNeg(V, "tmp.", InsertPt);
+ V = InsertBinop(Instruction::Sub, Constant::getNullValue(V->getType()), V,
+ InsertPt);
return V;
}
+Value *SCEVExpander::visitUDivExpr(SCEVUDivExpr *S) {
+ Value *LHS = expand(S->getLHS());
+ if (SCEVConstant *SC = dyn_cast<SCEVConstant>(S->getRHS())) {
+ const APInt &RHS = SC->getValue()->getValue();
+ if (RHS.isPowerOf2())
+ return InsertBinop(Instruction::LShr, LHS,
+ ConstantInt::get(S->getType(), RHS.logBase2()),
+ InsertPt);
+ }
+
+ Value *RHS = expand(S->getRHS());
+ return InsertBinop(Instruction::UDiv, LHS, RHS, InsertPt);
+}
+
+Value *SCEVExpander::visitSDivExpr(SCEVSDivExpr *S) {
+ // Do not fold sdiv into ashr, unless you know that LHS is positive. On
+ // negative values, it rounds the wrong way.
+
+ Value *LHS = expand(S->getLHS());
+ Value *RHS = expand(S->getRHS());
+ return InsertBinop(Instruction::SDiv, LHS, RHS, InsertPt);
+}
+
Value *SCEVExpander::visitAddRecExpr(SCEVAddRecExpr *S) {
const Type *Ty = S->getType();
const Loop *L = S->getLoop();
// We cannot yet do fp recurrences, e.g. the xform of {X,+,F} --> X+{0,+,F}
- assert(Ty->isIntegral() && "Cannot expand fp recurrences yet!");
+ assert(Ty->isInteger() && "Cannot expand fp recurrences yet!");
// {X,+,F} --> X + {0,+,F}
- if (!isa<SCEVConstant>(S->getStart()) ||
- !cast<SCEVConstant>(S->getStart())->getValue()->isNullValue()) {
- Value *Start = expandInTy(S->getStart(), Ty);
+ if (!S->getStart()->isZero()) {
+ Value *Start = expand(S->getStart());
std::vector<SCEVHandle> NewOps(S->op_begin(), S->op_end());
- NewOps[0] = SCEVUnknown::getIntegerSCEV(0, Ty);
- Value *Rest = expandInTy(SCEVAddRecExpr::get(NewOps, L), Ty);
+ NewOps[0] = SE.getIntegerSCEV(0, Ty);
+ Value *Rest = expand(SE.getAddRecExpr(NewOps, L));
// FIXME: look for an existing add to use.
- return BinaryOperator::createAdd(Rest, Start, "tmp.", InsertPt);
+ return InsertBinop(Instruction::Add, Rest, Start, InsertPt);
}
// {0,+,1} --> Insert a canonical induction variable into the loop!
- if (S->getNumOperands() == 2 &&
- S->getOperand(1) == SCEVUnknown::getIntegerSCEV(1, Ty)) {
+ if (S->isAffine() &&
+ S->getOperand(1) == SE.getIntegerSCEV(1, Ty)) {
// Create and insert the PHI node for the induction variable in the
// specified loop.
BasicBlock *Header = L->getHeader();
- PHINode *PN = new PHINode(Ty, "indvar", Header->begin());
+ PHINode *PN = PHINode::Create(Ty, "indvar", Header->begin());
PN->addIncoming(Constant::getNullValue(Ty), L->getLoopPreheader());
pred_iterator HPI = pred_begin(Header);
// Insert a unit add instruction right before the terminator corresponding
// to the back-edge.
- Constant *One = Ty->isFloatingPoint() ? (Constant*)ConstantFP::get(Ty, 1.0)
- : ConstantInt::get(Ty, 1);
- Instruction *Add = BinaryOperator::createAdd(PN, One, "indvar.next",
+ Constant *One = ConstantInt::get(Ty, 1);
+ Instruction *Add = BinaryOperator::CreateAdd(PN, One, "indvar.next",
(*HPI)->getTerminator());
pred_iterator PI = pred_begin(Header);
Value *I = getOrInsertCanonicalInductionVariable(L, Ty);
// If this is a simple linear addrec, emit it now as a special case.
- if (S->getNumOperands() == 2) { // {0,+,F} --> i*F
- Value *F = expandInTy(S->getOperand(1), Ty);
+ if (S->isAffine()) { // {0,+,F} --> i*F
+ Value *F = expand(S->getOperand(1));
// IF the step is by one, just return the inserted IV.
- if (ConstantIntegral *CI = dyn_cast<ConstantIntegral>(F))
- if (CI->getZExtValue() == 1)
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(F))
+ if (CI->getValue() == 1)
return I;
// If the insert point is directly inside of the loop, emit the multiply at
Loop *InsertPtLoop = LI.getLoopFor(MulInsertPt->getParent());
if (InsertPtLoop != L && InsertPtLoop &&
L->contains(InsertPtLoop->getHeader())) {
- while (InsertPtLoop != L) {
+ do {
// If we cannot hoist the multiply out of this loop, don't.
if (!InsertPtLoop->isLoopInvariant(F)) break;
- // Otherwise, move the insert point to the preheader of the loop.
- MulInsertPt = InsertPtLoop->getLoopPreheader()->getTerminator();
+ BasicBlock *InsertPtLoopPH = InsertPtLoop->getLoopPreheader();
+
+ // If this loop hasn't got a preheader, we aren't able to hoist the
+ // multiply.
+ if (!InsertPtLoopPH)
+ break;
+
+ // Otherwise, move the insert point to the preheader.
+ MulInsertPt = InsertPtLoopPH->getTerminator();
InsertPtLoop = InsertPtLoop->getParentLoop();
- }
+ } while (InsertPtLoop != L);
}
- return BinaryOperator::createMul(I, F, "tmp.", MulInsertPt);
+ return InsertBinop(Instruction::Mul, I, F, MulInsertPt);
}
// If this is a chain of recurrences, turn it into a closed form, using the
// folders, then expandCodeFor the closed form. This allows the folders to
// simplify the expression without having to build a bunch of special code
// into this folder.
- SCEVHandle IH = SCEVUnknown::get(I); // Get I as a "symbolic" SCEV.
+ SCEVHandle IH = SE.getUnknown(I); // Get I as a "symbolic" SCEV.
+
+ SCEVHandle V = S->evaluateAtIteration(IH, SE);
+ //cerr << "Evaluated: " << *this << "\n to: " << *V << "\n";
+
+ return expand(V);
+}
+
+Value *SCEVExpander::visitTruncateExpr(SCEVTruncateExpr *S) {
+ Value *V = expand(S->getOperand());
+ return CastInst::CreateTruncOrBitCast(V, S->getType(), "tmp.", InsertPt);
+}
+
+Value *SCEVExpander::visitZeroExtendExpr(SCEVZeroExtendExpr *S) {
+ Value *V = expand(S->getOperand());
+ return CastInst::CreateZExtOrBitCast(V, S->getType(), "tmp.", InsertPt);
+}
+
+Value *SCEVExpander::visitSignExtendExpr(SCEVSignExtendExpr *S) {
+ Value *V = expand(S->getOperand());
+ return CastInst::CreateSExtOrBitCast(V, S->getType(), "tmp.", InsertPt);
+}
+
+Value *SCEVExpander::visitSMaxExpr(SCEVSMaxExpr *S) {
+ Value *LHS = expand(S->getOperand(0));
+ for (unsigned i = 1; i < S->getNumOperands(); ++i) {
+ Value *RHS = expand(S->getOperand(i));
+ Value *ICmp = new ICmpInst(ICmpInst::ICMP_SGT, LHS, RHS, "tmp", InsertPt);
+ LHS = SelectInst::Create(ICmp, LHS, RHS, "smax", InsertPt);
+ }
+ return LHS;
+}
- SCEVHandle V = S->evaluateAtIteration(IH);
- //llvm_cerr << "Evaluated: " << *this << "\n to: " << *V << "\n";
+Value *SCEVExpander::visitUMaxExpr(SCEVUMaxExpr *S) {
+ Value *LHS = expand(S->getOperand(0));
+ for (unsigned i = 1; i < S->getNumOperands(); ++i) {
+ Value *RHS = expand(S->getOperand(i));
+ Value *ICmp = new ICmpInst(ICmpInst::ICMP_UGT, LHS, RHS, "tmp", InsertPt);
+ LHS = SelectInst::Create(ICmp, LHS, RHS, "umax", InsertPt);
+ }
+ return LHS;
+}
+
+Value *SCEVExpander::expandCodeFor(SCEVHandle SH, Instruction *IP) {
+ // Expand the code for this SCEV.
+ this->InsertPt = IP;
+ return expand(SH);
+}
- return expandInTy(V, Ty);
+Value *SCEVExpander::expand(SCEV *S) {
+ // Check to see if we already expanded this.
+ std::map<SCEVHandle, Value*>::iterator I = InsertedExpressions.find(S);
+ if (I != InsertedExpressions.end())
+ return I->second;
+
+ Value *V = visit(S);
+ InsertedExpressions[S] = V;
+ return V;
}
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