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Change SCEVExpander to use an IRBuilder to emit instructions.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74391 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2009-06-27 21:18:18 +00:00
parent 1d3b26ac02
commit 267a385342
2 changed files with 84 additions and 92 deletions
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34
include/llvm/Analysis/ScalarEvolutionExpander.h
View File

@ -14,10 +14,9 @@
#ifndef LLVM_ANALYSIS_SCALAREVOLUTION_EXPANDER_H
#define LLVM_ANALYSIS_SCALAREVOLUTION_EXPANDER_H
#include "llvm/Instructions.h"
#include "llvm/Type.h"
#include "llvm/Analysis/ScalarEvolution.h"
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
#include "llvm/Support/IRBuilder.h"
#include "llvm/Support/TargetFolder.h"
namespace llvm {
/// SCEVExpander - This class uses information about analyze scalars to
@ -32,12 +31,13 @@ namespace llvm {
InsertedExpressions;
std::set<Value*> InsertedValues;
BasicBlock::iterator InsertPt;
typedef IRBuilder<true, TargetFolder> BuilderType;
BuilderType Builder;
friend struct SCEVVisitor<SCEVExpander, Value*>;
public:
explicit SCEVExpander(ScalarEvolution &se)
: SE(se) {}
: SE(se), Builder(TargetFolder(se.TD)) {}
/// clear - Erase the contents of the InsertedExpressions map so that users
/// trying to expand the same expression into multiple BasicBlocks or
@ -53,27 +53,21 @@ namespace llvm {
/// expandCodeFor - Insert code to directly compute the specified SCEV
/// expression into the program. The inserted code is inserted into the
/// specified block.
Value *expandCodeFor(const SCEV* SH, const Type *Ty,
BasicBlock::iterator IP) {
InsertPt = IP;
Value *expandCodeFor(const SCEV* SH, const Type *Ty, Instruction *IP) {
Builder.SetInsertPoint(IP->getParent(), IP);
return expandCodeFor(SH, Ty);
}
/// InsertCastOfTo - Insert a cast of V to the specified type, doing what
/// we can to share the casts.
Value *InsertCastOfTo(Instruction::CastOps opcode, Value *V,
const Type *Ty);
/// InsertNoopCastOfTo - Insert a cast of V to the specified type,
/// which must be possible with a noop cast.
Value *InsertNoopCastOfTo(Value *V, const Type *Ty);
private:
/// InsertBinop - Insert the specified binary operator, doing a small amount
/// of work to avoid inserting an obviously redundant operation.
Value *InsertBinop(Instruction::BinaryOps Opcode, Value *LHS,
Value *RHS, BasicBlock::iterator InsertPt);
Value *InsertBinop(Instruction::BinaryOps Opcode, Value *LHS, Value *RHS);
/// InsertNoopCastOfTo - Insert a cast of V to the specified type,
/// which must be possible with a noop cast, doing what we can to
/// share the casts.
Value *InsertNoopCastOfTo(Value *V, const Type *Ty);
private:
/// expandAddToGEP - Expand a SCEVAddExpr with a pointer type into a GEP
/// instead of using ptrtoint+arithmetic+inttoptr.
Value *expandAddToGEP(const SCEV* const *op_begin,

142
lib/Analysis/ScalarEvolutionExpander.cpp
View File

@ -19,16 +19,24 @@
#include "llvm/ADT/STLExtras.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(Instruction::CastOps opcode, Value *V,
const Type *Ty) {
/// InsertNoopCastOfTo - Insert a cast of V to the specified type,
/// which must be possible with a noop cast, doing what we can to share
/// the casts.
Value *SCEVExpander::InsertNoopCastOfTo(Value *V, const Type *Ty) {
Instruction::CastOps Op = CastInst::getCastOpcode(V, false, Ty, false);
assert((Op == Instruction::BitCast ||
Op == Instruction::PtrToInt ||
Op == Instruction::IntToPtr) &&
"InsertNoopCastOfTo cannot perform non-noop casts!");
assert(SE.getTypeSizeInBits(V->getType()) == SE.getTypeSizeInBits(Ty) &&
"InsertNoopCastOfTo cannot change sizes!");
// Short-circuit unnecessary bitcasts.
if (opcode == Instruction::BitCast && V->getType() == Ty)
if (Op == Instruction::BitCast && V->getType() == Ty)
return V;
// Short-circuit unnecessary inttoptr<->ptrtoint casts.
if ((opcode == Instruction::PtrToInt || opcode == Instruction::IntToPtr) &&
if ((Op == Instruction::PtrToInt || Op == Instruction::IntToPtr) &&
SE.getTypeSizeInBits(Ty) == SE.getTypeSizeInBits(V->getType())) {
if (CastInst *CI = dyn_cast<CastInst>(V))
if ((CI->getOpcode() == Instruction::PtrToInt ||
@ -46,7 +54,7 @@ Value *SCEVExpander::InsertCastOfTo(Instruction::CastOps opcode, Value *V,
// FIXME: keep track of the cast instruction.
if (Constant *C = dyn_cast<Constant>(V))
return ConstantExpr::getCast(opcode, C, Ty);
return ConstantExpr::getCast(Op, C, Ty);
if (Argument *A = dyn_cast<Argument>(V)) {
// Check to see if there is already a cast!
@ -54,7 +62,7 @@ Value *SCEVExpander::InsertCastOfTo(Instruction::CastOps opcode, Value *V,
UI != E; ++UI)
if ((*UI)->getType() == Ty)
if (CastInst *CI = dyn_cast<CastInst>(cast<Instruction>(*UI)))
if (CI->getOpcode() == opcode) {
if (CI->getOpcode() == Op) {
// If the cast isn't the first instruction of the function, move it.
if (BasicBlock::iterator(CI) !=
A->getParent()->getEntryBlock().begin()) {
@ -62,7 +70,7 @@ Value *SCEVExpander::InsertCastOfTo(Instruction::CastOps opcode, Value *V,
// The old cast is left in place in case it is being used
// as an insert point.
Instruction *NewCI =
CastInst::Create(opcode, V, Ty, "",
CastInst::Create(Op, V, Ty, "",
A->getParent()->getEntryBlock().begin());
NewCI->takeName(CI);
CI->replaceAllUsesWith(NewCI);
@ -71,7 +79,7 @@ Value *SCEVExpander::InsertCastOfTo(Instruction::CastOps opcode, Value *V,
return CI;
}
Instruction *I = CastInst::Create(opcode, V, Ty, V->getName(),
Instruction *I = CastInst::Create(Op, V, Ty, V->getName(),
A->getParent()->getEntryBlock().begin());
InsertedValues.insert(I);
return I;
@ -84,7 +92,7 @@ Value *SCEVExpander::InsertCastOfTo(Instruction::CastOps opcode, Value *V,
UI != E; ++UI) {
if ((*UI)->getType() == Ty)
if (CastInst *CI = dyn_cast<CastInst>(cast<Instruction>(*UI)))
if (CI->getOpcode() == opcode) {
if (CI->getOpcode() == Op) {
BasicBlock::iterator It = I; ++It;
if (isa<InvokeInst>(I))
It = cast<InvokeInst>(I)->getNormalDest()->begin();
@ -93,7 +101,7 @@ Value *SCEVExpander::InsertCastOfTo(Instruction::CastOps opcode, Value *V,
// Recreate the cast at the beginning of the entry block.
// The old cast is left in place in case it is being used
// as an insert point.
Instruction *NewCI = CastInst::Create(opcode, V, Ty, "", It);
Instruction *NewCI = CastInst::Create(Op, V, Ty, "", It);
NewCI->takeName(CI);
CI->replaceAllUsesWith(NewCI);
return NewCI;
@ -105,28 +113,15 @@ Value *SCEVExpander::InsertCastOfTo(Instruction::CastOps opcode, Value *V,
if (InvokeInst *II = dyn_cast<InvokeInst>(I))
IP = II->getNormalDest()->begin();
while (isa<PHINode>(IP)) ++IP;
Instruction *CI = CastInst::Create(opcode, V, Ty, V->getName(), IP);
Instruction *CI = CastInst::Create(Op, V, Ty, V->getName(), IP);
InsertedValues.insert(CI);
return CI;
}
/// InsertNoopCastOfTo - Insert a cast of V to the specified type,
/// which must be possible with a noop cast.
Value *SCEVExpander::InsertNoopCastOfTo(Value *V, const Type *Ty) {
Instruction::CastOps Op = CastInst::getCastOpcode(V, false, Ty, false);
assert((Op == Instruction::BitCast ||
Op == Instruction::PtrToInt ||
Op == Instruction::IntToPtr) &&
"InsertNoopCastOfTo cannot perform non-noop casts!");
assert(SE.getTypeSizeInBits(V->getType()) == SE.getTypeSizeInBits(Ty) &&
"InsertNoopCastOfTo cannot change sizes!");
return InsertCastOfTo(Op, V, Ty);
}
/// 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, BasicBlock::iterator InsertPt) {
Value *SCEVExpander::InsertBinop(Instruction::BinaryOps Opcode,
Value *LHS, Value *RHS) {
// Fold a binop with constant operands.
if (Constant *CLHS = dyn_cast<Constant>(LHS))
if (Constant *CRHS = dyn_cast<Constant>(RHS))
@ -134,10 +129,10 @@ Value *SCEVExpander::InsertBinop(Instruction::BinaryOps Opcode, Value *LHS,
// 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;
BasicBlock::iterator BlockBegin = Builder.GetInsertBlock()->begin();
// Scanning starts from the last instruction before the insertion point.
BasicBlock::iterator IP = Builder.GetInsertPoint();
if (IP != BlockBegin) {
--IP;
for (; ScanLimit; --IP, --ScanLimit) {
if (IP->getOpcode() == (unsigned)Opcode && IP->getOperand(0) == LHS &&
@ -146,9 +141,9 @@ Value *SCEVExpander::InsertBinop(Instruction::BinaryOps Opcode, Value *LHS,
if (IP == BlockBegin) break;
}
}
// If we haven't found this binop, insert it.
Instruction *BO = BinaryOperator::Create(Opcode, LHS, RHS, "tmp", InsertPt);
Value *BO = Builder.CreateBinOp(Opcode, LHS, RHS, "tmp");
InsertedValues.insert(BO);
return BO;
}
@ -336,10 +331,10 @@ Value *SCEVExpander::expandAddToGEP(const SCEV* const *op_begin,
// Do a quick scan to see if we have this GEP 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;
BasicBlock::iterator BlockBegin = Builder.GetInsertBlock()->begin();
// Scanning starts from the last instruction before the insertion point.
BasicBlock::iterator IP = Builder.GetInsertPoint();
if (IP != BlockBegin) {
--IP;
for (; ScanLimit; --IP, --ScanLimit) {
if (IP->getOpcode() == Instruction::GetElementPtr &&
@ -349,16 +344,16 @@ Value *SCEVExpander::expandAddToGEP(const SCEV* const *op_begin,
}
}
Value *GEP = GetElementPtrInst::Create(V, Idx, "scevgep", InsertPt);
Value *GEP = Builder.CreateGEP(V, Idx, "scevgep");
InsertedValues.insert(GEP);
return GEP;
}
// Insert a pretty getelementptr.
Value *GEP = GetElementPtrInst::Create(V,
GepIndices.begin(),
GepIndices.end(),
"scevgep", InsertPt);
Value *GEP = Builder.CreateGEP(V,
GepIndices.begin(),
GepIndices.end(),
"scevgep");
Ops.push_back(SE.getUnknown(GEP));
InsertedValues.insert(GEP);
return expand(SE.getAddExpr(Ops));
@ -382,7 +377,7 @@ Value *SCEVExpander::visitAddExpr(const SCEVAddExpr *S) {
// Emit a bunch of add instructions
for (int i = S->getNumOperands()-2; i >= 0; --i) {
Value *W = expandCodeFor(S->getOperand(i), Ty);
V = InsertBinop(Instruction::Add, V, W, InsertPt);
V = InsertBinop(Instruction::Add, V, W);
}
return V;
}
@ -400,12 +395,12 @@ Value *SCEVExpander::visitMulExpr(const SCEVMulExpr *S) {
// Emit a bunch of multiply instructions
for (; i >= FirstOp; --i) {
Value *W = expandCodeFor(S->getOperand(i), Ty);
V = InsertBinop(Instruction::Mul, V, W, InsertPt);
V = InsertBinop(Instruction::Mul, V, W);
}
// -1 * ... ---> 0 - ...
if (FirstOp == 1)
V = InsertBinop(Instruction::Sub, Constant::getNullValue(Ty), V, InsertPt);
V = InsertBinop(Instruction::Sub, Constant::getNullValue(Ty), V);
return V;
}
@ -417,12 +412,11 @@ Value *SCEVExpander::visitUDivExpr(const SCEVUDivExpr *S) {
const APInt &RHS = SC->getValue()->getValue();
if (RHS.isPowerOf2())
return InsertBinop(Instruction::LShr, LHS,
ConstantInt::get(Ty, RHS.logBase2()),
InsertPt);
ConstantInt::get(Ty, RHS.logBase2()));
}
Value *RHS = expandCodeFor(S->getRHS(), Ty);
return InsertBinop(Instruction::UDiv, LHS, RHS, InsertPt);
return InsertBinop(Instruction::UDiv, LHS, RHS);
}
/// Move parts of Base into Rest to leave Base with the minimal
@ -468,13 +462,14 @@ Value *SCEVExpander::visitAddRecExpr(const SCEVAddRecExpr *S) {
const SCEV* Step = SE.getAnyExtendExpr(S->getStepRecurrence(SE),
CanonicalIV->getType());
Value *V = expand(SE.getAddRecExpr(Start, Step, S->getLoop()));
BasicBlock::iterator SaveInsertPt = InsertPt;
BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
BasicBlock::iterator NewInsertPt =
next(BasicBlock::iterator(cast<Instruction>(V)));
while (isa<PHINode>(NewInsertPt)) ++NewInsertPt;
V = expandCodeFor(SE.getTruncateExpr(SE.getUnknown(V), Ty), 0,
NewInsertPt);
InsertPt = SaveInsertPt;
Builder.SetInsertPoint(SaveInsertBB, SaveInsertPt);
return V;
}
@ -524,9 +519,10 @@ Value *SCEVExpander::visitAddRecExpr(const SCEVAddRecExpr *S) {
// Create and insert the PHI node for the induction variable in the
// specified loop.
BasicBlock *Header = L->getHeader();
BasicBlock *Preheader = L->getLoopPreheader();
PHINode *PN = PHINode::Create(Ty, "indvar", Header->begin());
InsertedValues.insert(PN);
PN->addIncoming(Constant::getNullValue(Ty), L->getLoopPreheader());
PN->addIncoming(Constant::getNullValue(Ty), Preheader);
pred_iterator HPI = pred_begin(Header);
assert(HPI != pred_end(Header) && "Loop with zero preds???");
@ -542,7 +538,7 @@ Value *SCEVExpander::visitAddRecExpr(const SCEVAddRecExpr *S) {
InsertedValues.insert(Add);
pred_iterator PI = pred_begin(Header);
if (*PI == L->getLoopPreheader())
if (*PI == Preheader)
++PI;
PN->addIncoming(Add, *PI);
return PN;
@ -587,7 +583,7 @@ Value *SCEVExpander::visitTruncateExpr(const SCEVTruncateExpr *S) {
const Type *Ty = SE.getEffectiveSCEVType(S->getType());
Value *V = expandCodeFor(S->getOperand(),
SE.getEffectiveSCEVType(S->getOperand()->getType()));
Instruction *I = new TruncInst(V, Ty, "tmp.", InsertPt);
Value *I = Builder.CreateTrunc(V, Ty, "tmp");
InsertedValues.insert(I);
return I;
}
@ -596,7 +592,7 @@ Value *SCEVExpander::visitZeroExtendExpr(const SCEVZeroExtendExpr *S) {
const Type *Ty = SE.getEffectiveSCEVType(S->getType());
Value *V = expandCodeFor(S->getOperand(),
SE.getEffectiveSCEVType(S->getOperand()->getType()));
Instruction *I = new ZExtInst(V, Ty, "tmp.", InsertPt);
Value *I = Builder.CreateZExt(V, Ty, "tmp");
InsertedValues.insert(I);
return I;
}
@ -605,7 +601,7 @@ Value *SCEVExpander::visitSignExtendExpr(const SCEVSignExtendExpr *S) {
const Type *Ty = SE.getEffectiveSCEVType(S->getType());
Value *V = expandCodeFor(S->getOperand(),
SE.getEffectiveSCEVType(S->getOperand()->getType()));
Instruction *I = new SExtInst(V, Ty, "tmp.", InsertPt);
Value *I = Builder.CreateSExt(V, Ty, "tmp");
InsertedValues.insert(I);
return I;
}
@ -615,10 +611,9 @@ Value *SCEVExpander::visitSMaxExpr(const SCEVSMaxExpr *S) {
Value *LHS = expandCodeFor(S->getOperand(0), Ty);
for (unsigned i = 1; i < S->getNumOperands(); ++i) {
Value *RHS = expandCodeFor(S->getOperand(i), Ty);
Instruction *ICmp =
new ICmpInst(ICmpInst::ICMP_SGT, LHS, RHS, "tmp", InsertPt);
Value *ICmp = Builder.CreateICmpSGT(LHS, RHS, "tmp");
InsertedValues.insert(ICmp);
Instruction *Sel = SelectInst::Create(ICmp, LHS, RHS, "smax", InsertPt);
Value *Sel = Builder.CreateSelect(ICmp, LHS, RHS, "smax");
InsertedValues.insert(Sel);
LHS = Sel;
}
@ -630,10 +625,9 @@ Value *SCEVExpander::visitUMaxExpr(const SCEVUMaxExpr *S) {
Value *LHS = expandCodeFor(S->getOperand(0), Ty);
for (unsigned i = 1; i < S->getNumOperands(); ++i) {
Value *RHS = expandCodeFor(S->getOperand(i), Ty);
Instruction *ICmp =
new ICmpInst(ICmpInst::ICMP_UGT, LHS, RHS, "tmp", InsertPt);
Value *ICmp = Builder.CreateICmpUGT(LHS, RHS, "tmp");
InsertedValues.insert(ICmp);
Instruction *Sel = SelectInst::Create(ICmp, LHS, RHS, "umax", InsertPt);
Value *Sel = Builder.CreateSelect(ICmp, LHS, RHS, "umax");
InsertedValues.insert(Sel);
LHS = Sel;
}
@ -652,11 +646,10 @@ Value *SCEVExpander::expandCodeFor(const SCEV* SH, const Type *Ty) {
}
Value *SCEVExpander::expand(const SCEV *S) {
BasicBlock::iterator SaveInsertPt = InsertPt;
// Compute an insertion point for this SCEV object. Hoist the instructions
// as far out in the loop nest as possible.
for (Loop *L = SE.LI->getLoopFor(InsertPt->getParent()); ;
Instruction *InsertPt = Builder.GetInsertPoint();
for (Loop *L = SE.LI->getLoopFor(Builder.GetInsertBlock()); ;
L = L->getParentLoop())
if (S->isLoopInvariant(L)) {
if (!L) break;
@ -668,7 +661,8 @@ Value *SCEVExpander::expand(const SCEV *S) {
// there) so that it is guaranteed to dominate any user inside the loop.
if (L && S->hasComputableLoopEvolution(L))
InsertPt = L->getHeader()->getFirstNonPHI();
while (isInsertedInstruction(InsertPt)) ++InsertPt;
while (isInsertedInstruction(InsertPt))
InsertPt = next(BasicBlock::iterator(InsertPt));
break;
}
@ -676,10 +670,12 @@ Value *SCEVExpander::expand(const SCEV *S) {
std::map<std::pair<const SCEV *, Instruction *>,
AssertingVH<Value> >::iterator I =
InsertedExpressions.find(std::make_pair(S, InsertPt));
if (I != InsertedExpressions.end()) {
InsertPt = SaveInsertPt;
if (I != InsertedExpressions.end())
return I->second;
}
BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
Builder.SetInsertPoint(InsertPt->getParent(), InsertPt);
// Expand the expression into instructions.
Value *V = visit(S);
@ -687,7 +683,7 @@ Value *SCEVExpander::expand(const SCEV *S) {
// Remember the expanded value for this SCEV at this location.
InsertedExpressions[std::make_pair(S, InsertPt)] = V;
InsertPt = SaveInsertPt;
Builder.SetInsertPoint(SaveInsertBB, SaveInsertPt);
return V;
}
@ -701,8 +697,10 @@ SCEVExpander::getOrInsertCanonicalInductionVariable(const Loop *L,
assert(Ty->isInteger() && "Can only insert integer induction variables!");
const SCEV* H = SE.getAddRecExpr(SE.getIntegerSCEV(0, Ty),
SE.getIntegerSCEV(1, Ty), L);
BasicBlock::iterator SaveInsertPt = InsertPt;
BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
Value *V = expandCodeFor(H, 0, L->getHeader()->begin());
InsertPt = SaveInsertPt;
if (SaveInsertBB)
Builder.SetInsertPoint(SaveInsertBB, SaveInsertPt);
return V;
}