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Break SCEVExpander out of IndVarSimplify into its own .h/.cpp file so that
other passes may use it. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22557 91177308-0d34-0410-b5e6-96231b3b80d8
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include/llvm/Analysis/ScalarEvolutionExpander.h
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180
include/llvm/Analysis/ScalarEvolutionExpander.h
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@ -0,0 +1,180 @@
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//===---- llvm/Analysis/ScalarEvolutionExpander.h - SCEV Exprs --*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by the LLVM research group and is distributed under
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// the University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines the classes used to generate code from scalar expressions.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_ANALYSIS_SCALAREVOLUTION_EXPANDER_H
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#define LLVM_ANALYSIS_SCALAREVOLUTION_EXPANDER_H
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#include "llvm/BasicBlock.h"
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#include "llvm/Constants.h"
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#include "llvm/Instructions.h"
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#include "llvm/Type.h"
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#include "llvm/Analysis/ScalarEvolution.h"
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#include "llvm/Analysis/ScalarEvolutionExpressions.h"
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#include "llvm/Support/CFG.h"
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namespace llvm {
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/// SCEVExpander - This class uses information about analyze scalars to
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/// rewrite expressions in canonical form.
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///
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/// Clients should create an instance of this class when rewriting is needed,
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/// and destroying it when finished to allow the release of the associated
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/// memory.
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struct SCEVExpander : public SCEVVisitor<SCEVExpander, Value*> {
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ScalarEvolution &SE;
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LoopInfo &LI;
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std::map<SCEVHandle, Value*> InsertedExpressions;
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std::set<Instruction*> InsertedInstructions;
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Instruction *InsertPt;
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friend struct SCEVVisitor<SCEVExpander, Value*>;
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public:
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SCEVExpander(ScalarEvolution &se, LoopInfo &li) : SE(se), LI(li) {}
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/// clear - Erase the contents of the InsertedExpressions map so that users
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/// trying to expand the same expression into multiple BasicBlocks or
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/// different places within the same BasicBlock can do so.
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void clear() { InsertedExpressions.clear(); }
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/// isInsertedInstruction - Return true if the specified instruction was
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/// inserted by the code rewriter. If so, the client should not modify the
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/// instruction.
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bool isInsertedInstruction(Instruction *I) const {
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return InsertedInstructions.count(I);
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}
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/// getOrInsertCanonicalInductionVariable - This method returns the
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/// canonical induction variable of the specified type for the specified
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/// loop (inserting one if there is none). A canonical induction variable
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/// starts at zero and steps by one on each iteration.
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Value *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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SCEVHandle H = SCEVAddRecExpr::get(SCEVUnknown::getIntegerSCEV(0, Ty),
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SCEVUnknown::getIntegerSCEV(1, Ty), L);
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return expand(H);
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}
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/// addInsertedValue - Remember the specified instruction as being the
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/// canonical form for the specified SCEV.
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void addInsertedValue(Instruction *I, SCEV *S) {
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InsertedExpressions[S] = (Value*)I;
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InsertedInstructions.insert(I);
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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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///
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/// If a particular value sign is required, a type may be specified for the
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/// result.
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Value *expandCodeFor(SCEVHandle SH, Instruction *IP, const Type *Ty = 0) {
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// Expand the code for this SCEV.
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this->InsertPt = IP;
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return expandInTy(SH, Ty);
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}
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protected:
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Value *expand(SCEV *S) {
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// Check to see if we already expanded this.
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std::map<SCEVHandle, Value*>::iterator I = InsertedExpressions.find(S);
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if (I != InsertedExpressions.end())
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return I->second;
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Value *V = visit(S);
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InsertedExpressions[S] = V;
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return V;
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}
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Value *expandInTy(SCEV *S, const Type *Ty) {
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Value *V = expand(S);
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if (Ty && V->getType() != Ty) {
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// FIXME: keep track of the cast instruction.
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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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if (isa<InvokeInst>(I))
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It = cast<InvokeInst>(I)->getNormalDest()->begin();
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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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BasicBlock::InstListType &InstList =
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It->getParent()->getInstList();
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InstList.splice(It, CI->getParent()->getInstList(), 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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return V;
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}
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Value *visitConstant(SCEVConstant *S) {
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return S->getValue();
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}
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Value *visitTruncateExpr(SCEVTruncateExpr *S) {
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Value *V = expand(S->getOperand());
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return new CastInst(V, S->getType(), "tmp.", InsertPt);
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}
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Value *visitZeroExtendExpr(SCEVZeroExtendExpr *S) {
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Value *V = expandInTy(S->getOperand(),S->getType()->getUnsignedVersion());
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return new CastInst(V, S->getType(), "tmp.", InsertPt);
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}
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Value *visitAddExpr(SCEVAddExpr *S) {
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const Type *Ty = S->getType();
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Value *V = expandInTy(S->getOperand(S->getNumOperands()-1), Ty);
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// Emit a bunch of add instructions
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for (int i = S->getNumOperands()-2; i >= 0; --i)
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V = BinaryOperator::createAdd(V, expandInTy(S->getOperand(i), Ty),
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"tmp.", InsertPt);
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return V;
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}
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Value *visitMulExpr(SCEVMulExpr *S);
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Value *visitUDivExpr(SCEVUDivExpr *S) {
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const Type *Ty = S->getType();
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Value *LHS = expandInTy(S->getLHS(), Ty);
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Value *RHS = expandInTy(S->getRHS(), Ty);
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return BinaryOperator::createDiv(LHS, RHS, "tmp.", InsertPt);
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}
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Value *visitAddRecExpr(SCEVAddRecExpr *S);
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Value *visitUnknown(SCEVUnknown *S) {
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return S->getValue();
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}
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};
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}
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#endif
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105
lib/Analysis/ScalarEvolutionExpander.cpp
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105
lib/Analysis/ScalarEvolutionExpander.cpp
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@ -0,0 +1,105 @@
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//===- ScalarEvolutionExpander.cpp - Scalar Evolution Analysis --*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by the LLVM research group and is distributed under
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// the University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file contains the implementation of the scalar evolution expander,
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// which is used to generate the code corresponding to a given scalar evolution
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// expression.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Analysis/LoopInfo.h"
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#include "llvm/Analysis/ScalarEvolutionExpander.h"
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using namespace llvm;
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Value *SCEVExpander::visitMulExpr(SCEVMulExpr *S) {
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const Type *Ty = S->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>(S->getOperand(0)))
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if (SC->getValue()->isAllOnesValue())
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FirstOp = 1;
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int i = S->getNumOperands()-2;
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Value *V = expandInTy(S->getOperand(i+1), 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::createMul(V, expandInTy(S->getOperand(i), 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::createNeg(V, "tmp.", InsertPt);
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return V;
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}
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Value *SCEVExpander::visitAddRecExpr(SCEVAddRecExpr *S) {
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const Type *Ty = S->getType();
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const Loop *L = S->getLoop();
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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>(S->getStart()) ||
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!cast<SCEVConstant>(S->getStart())->getValue()->isNullValue()) {
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Value *Start = expandInTy(S->getStart(), Ty);
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std::vector<SCEVHandle> NewOps(S->op_begin(), S->op_end());
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NewOps[0] = SCEVUnknown::getIntegerSCEV(0, Ty);
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Value *Rest = expandInTy(SCEVAddRecExpr::get(NewOps, L), Ty);
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// FIXME: look for an existing add to use.
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return BinaryOperator::createAdd(Rest, Start, "tmp.", InsertPt);
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}
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// {0,+,1} --> Insert a canonical induction variable into the loop!
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if (S->getNumOperands() == 2 &&
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S->getOperand(1) == SCEVUnknown::getIntegerSCEV(1, Ty)) {
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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 = L->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 (!L->contains(*HPI)) ++HPI;
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assert(HPI != pred_end(Header) && L->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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: ConstantInt::get(Ty, 1);
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Instruction *Add = BinaryOperator::createAdd(PN, One, "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 = getOrInsertCanonicalInductionVariable(L, Ty);
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if (S->getNumOperands() == 2) { // {0,+,F} --> i*F
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Value *F = expandInTy(S->getOperand(1), Ty);
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return BinaryOperator::createMul(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 = S->evaluateAtIteration(IH);
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//std::cerr << "Evaluated: " << *this << "\n to: " << *V << "\n";
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return expandInTy(V, Ty);
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}
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@ -42,7 +42,7 @@
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#include "llvm/Constants.h"
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#include "llvm/Instructions.h"
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#include "llvm/Type.h"
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#include "llvm/Analysis/ScalarEvolutionExpressions.h"
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#include "llvm/Analysis/ScalarEvolutionExpander.h"
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#include "llvm/Analysis/LoopInfo.h"
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#include "llvm/Support/CFG.h"
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#include "llvm/Support/GetElementPtrTypeIterator.h"
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@ -51,243 +51,6 @@
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#include "llvm/ADT/Statistic.h"
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using namespace llvm;
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namespace {
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/// SCEVExpander - This class uses information about analyze scalars to
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/// rewrite expressions in canonical form.
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///
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/// Clients should create an instance of this class when rewriting is needed,
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/// and destroying it when finished to allow the release of the associated
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/// memory.
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struct SCEVExpander : public SCEVVisitor<SCEVExpander, Value*> {
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ScalarEvolution &SE;
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LoopInfo &LI;
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std::map<SCEVHandle, Value*> InsertedExpressions;
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std::set<Instruction*> InsertedInstructions;
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Instruction *InsertPt;
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friend struct SCEVVisitor<SCEVExpander, Value*>;
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public:
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SCEVExpander(ScalarEvolution &se, LoopInfo &li) : SE(se), LI(li) {}
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/// isInsertedInstruction - Return true if the specified instruction was
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/// inserted by the code rewriter. If so, the client should not modify the
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/// instruction.
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bool isInsertedInstruction(Instruction *I) const {
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return InsertedInstructions.count(I);
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}
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/// getOrInsertCanonicalInductionVariable - This method returns the
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/// canonical induction variable of the specified type for the specified
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/// loop (inserting one if there is none). A canonical induction variable
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/// starts at zero and steps by one on each iteration.
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Value *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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SCEVHandle H = SCEVAddRecExpr::get(SCEVUnknown::getIntegerSCEV(0, Ty),
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SCEVUnknown::getIntegerSCEV(1, Ty), L);
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return expand(H);
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}
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/// addInsertedValue - Remember the specified instruction as being the
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/// canonical form for the specified SCEV.
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void addInsertedValue(Instruction *I, SCEV *S) {
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InsertedExpressions[S] = (Value*)I;
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InsertedInstructions.insert(I);
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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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///
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/// If a particular value sign is required, a type may be specified for the
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/// result.
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Value *expandCodeFor(SCEVHandle SH, Instruction *IP, const Type *Ty = 0) {
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// Expand the code for this SCEV.
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this->InsertPt = IP;
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return expandInTy(SH, Ty);
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}
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protected:
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Value *expand(SCEV *S) {
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// Check to see if we already expanded this.
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std::map<SCEVHandle, Value*>::iterator I = InsertedExpressions.find(S);
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if (I != InsertedExpressions.end())
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return I->second;
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Value *V = visit(S);
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InsertedExpressions[S] = V;
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return V;
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}
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Value *expandInTy(SCEV *S, const Type *Ty) {
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Value *V = expand(S);
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if (Ty && V->getType() != Ty) {
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// FIXME: keep track of the cast instruction.
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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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if (isa<InvokeInst>(I))
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It = cast<InvokeInst>(I)->getNormalDest()->begin();
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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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BasicBlock::InstListType &InstList =
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It->getParent()->getInstList();
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InstList.splice(It, CI->getParent()->getInstList(), 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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return V;
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}
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Value *visitConstant(SCEVConstant *S) {
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return S->getValue();
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}
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Value *visitTruncateExpr(SCEVTruncateExpr *S) {
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Value *V = expand(S->getOperand());
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return new CastInst(V, S->getType(), "tmp.", InsertPt);
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}
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Value *visitZeroExtendExpr(SCEVZeroExtendExpr *S) {
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Value *V = expandInTy(S->getOperand(),S->getType()->getUnsignedVersion());
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return new CastInst(V, S->getType(), "tmp.", InsertPt);
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}
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Value *visitAddExpr(SCEVAddExpr *S) {
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const Type *Ty = S->getType();
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Value *V = expandInTy(S->getOperand(S->getNumOperands()-1), Ty);
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// Emit a bunch of add instructions
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for (int i = S->getNumOperands()-2; i >= 0; --i)
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V = BinaryOperator::createAdd(V, expandInTy(S->getOperand(i), Ty),
|
||||
"tmp.", InsertPt);
|
||||
return V;
|
||||
}
|
||||
|
||||
Value *visitMulExpr(SCEVMulExpr *S);
|
||||
|
||||
Value *visitUDivExpr(SCEVUDivExpr *S) {
|
||||
const Type *Ty = S->getType();
|
||||
Value *LHS = expandInTy(S->getLHS(), Ty);
|
||||
Value *RHS = expandInTy(S->getRHS(), Ty);
|
||||
return BinaryOperator::createDiv(LHS, RHS, "tmp.", InsertPt);
|
||||
}
|
||||
|
||||
Value *visitAddRecExpr(SCEVAddRecExpr *S);
|
||||
|
||||
Value *visitUnknown(SCEVUnknown *S) {
|
||||
return S->getValue();
|
||||
}
|
||||
};
|
||||
}
|
||||
|
||||
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);
|
||||
|
||||
// Emit a bunch of multiply instructions
|
||||
for (; i >= FirstOp; --i)
|
||||
V = BinaryOperator::createMul(V, expandInTy(S->getOperand(i), Ty),
|
||||
"tmp.", InsertPt);
|
||||
// -1 * ... ---> 0 - ...
|
||||
if (FirstOp == 1)
|
||||
V = BinaryOperator::createNeg(V, "tmp.", InsertPt);
|
||||
return V;
|
||||
}
|
||||
|
||||
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!");
|
||||
|
||||
// {X,+,F} --> X + {0,+,F}
|
||||
if (!isa<SCEVConstant>(S->getStart()) ||
|
||||
!cast<SCEVConstant>(S->getStart())->getValue()->isNullValue()) {
|
||||
Value *Start = expandInTy(S->getStart(), Ty);
|
||||
std::vector<SCEVHandle> NewOps(S->op_begin(), S->op_end());
|
||||
NewOps[0] = SCEVUnknown::getIntegerSCEV(0, Ty);
|
||||
Value *Rest = expandInTy(SCEVAddRecExpr::get(NewOps, L), Ty);
|
||||
|
||||
// FIXME: look for an existing add to use.
|
||||
return BinaryOperator::createAdd(Rest, Start, "tmp.", InsertPt);
|
||||
}
|
||||
|
||||
// {0,+,1} --> Insert a canonical induction variable into the loop!
|
||||
if (S->getNumOperands() == 2 &&
|
||||
S->getOperand(1) == SCEVUnknown::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());
|
||||
PN->addIncoming(Constant::getNullValue(Ty), L->getLoopPreheader());
|
||||
|
||||
pred_iterator HPI = pred_begin(Header);
|
||||
assert(HPI != pred_end(Header) && "Loop with zero preds???");
|
||||
if (!L->contains(*HPI)) ++HPI;
|
||||
assert(HPI != pred_end(Header) && L->contains(*HPI) &&
|
||||
"No backedge in loop?");
|
||||
|
||||
// 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",
|
||||
(*HPI)->getTerminator());
|
||||
|
||||
pred_iterator PI = pred_begin(Header);
|
||||
if (*PI == L->getLoopPreheader())
|
||||
++PI;
|
||||
PN->addIncoming(Add, *PI);
|
||||
return PN;
|
||||
}
|
||||
|
||||
// Get the canonical induction variable I for this loop.
|
||||
Value *I = getOrInsertCanonicalInductionVariable(L, Ty);
|
||||
|
||||
if (S->getNumOperands() == 2) { // {0,+,F} --> i*F
|
||||
Value *F = expandInTy(S->getOperand(1), Ty);
|
||||
return BinaryOperator::createMul(I, F, "tmp.", InsertPt);
|
||||
}
|
||||
|
||||
// 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 V = S->evaluateAtIteration(IH);
|
||||
//std::cerr << "Evaluated: " << *this << "\n to: " << *V << "\n";
|
||||
|
||||
return expandInTy(V, Ty);
|
||||
}
|
||||
|
||||
|
||||
namespace {
|
||||
Statistic<> NumRemoved ("indvars", "Number of aux indvars removed");
|
||||
Statistic<> NumPointer ("indvars", "Number of pointer indvars promoted");
|
||||
|
Loading…
Reference in New Issue
Block a user