#include "llvm/Analysis/Dominators.h"
#include "llvm/Analysis/LoopPass.h"
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
-#include "llvm/Assembly/AsmAnnotationWriter.h"
+#include "llvm/Assembly/Writer.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
char IVUsers::ID = 0;
-static RegisterPass<IVUsers>
-X("iv-users", "Induction Variable Users", false, true);
+INITIALIZE_PASS_BEGIN(IVUsers, "iv-users",
+ "Induction Variable Users", false, true)
+INITIALIZE_PASS_DEPENDENCY(LoopInfo)
+INITIALIZE_PASS_DEPENDENCY(DominatorTree)
+INITIALIZE_PASS_DEPENDENCY(ScalarEvolution)
+INITIALIZE_PASS_END(IVUsers, "iv-users",
+ "Induction Variable Users", false, true)
Pass *llvm::createIVUsersPass() {
return new IVUsers();
}
-/// CollectSubexprs - Split S into subexpressions which can be pulled out into
-/// separate registers.
-static void CollectSubexprs(const SCEV *S,
- SmallVectorImpl<const SCEV *> &Ops,
- ScalarEvolution &SE) {
- if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(S)) {
- // Break out add operands.
- for (SCEVAddExpr::op_iterator I = Add->op_begin(), E = Add->op_end();
- I != E; ++I)
- CollectSubexprs(*I, Ops, SE);
- return;
- } else if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S)) {
- // Split a non-zero base out of an addrec.
- if (!AR->getStart()->isZero()) {
- CollectSubexprs(AR->getStart(), Ops, SE);
- CollectSubexprs(SE.getAddRecExpr(SE.getIntegerSCEV(0, AR->getType()),
- AR->getStepRecurrence(SE),
- AR->getLoop()), Ops, SE);
- return;
- }
- }
-
- // Otherwise use the value itself.
- Ops.push_back(S);
-}
-
/// isInteresting - Test whether the given expression is "interesting" when
/// used by the given expression, within the context of analyzing the
/// given loop.
-static bool isInteresting(const SCEV *S, const Instruction *I, const Loop *L) {
- // Anything loop-invariant is interesting.
- if (!isa<SCEVUnknown>(S) && S->isLoopInvariant(L))
- return true;
-
+static bool isInteresting(const SCEV *S, const Instruction *I, const Loop *L,
+ ScalarEvolution *SE) {
// An addrec is interesting if it's affine or if it has an interesting start.
if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S)) {
// Keep things simple. Don't touch loop-variant strides.
- if (AR->getLoop() == L && (AR->isAffine() || !L->contains(I)))
- return true;
- // Otherwise recurse to see if the start value is interesting.
- return isInteresting(AR->getStart(), I, L);
+ if (AR->getLoop() == L)
+ return AR->isAffine() || !L->contains(I);
+ // Otherwise recurse to see if the start value is interesting, and that
+ // the step value is not interesting, since we don't yet know how to
+ // do effective SCEV expansions for addrecs with interesting steps.
+ return isInteresting(AR->getStart(), I, L, SE) &&
+ !isInteresting(AR->getStepRecurrence(*SE), I, L, SE);
}
- // An add is interesting if any of its operands is.
+ // An add is interesting if exactly one of its operands is interesting.
if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(S)) {
+ bool AnyInterestingYet = false;
for (SCEVAddExpr::op_iterator OI = Add->op_begin(), OE = Add->op_end();
OI != OE; ++OI)
- if (isInteresting(*OI, I, L))
- return true;
- return false;
+ if (isInteresting(*OI, I, L, SE)) {
+ if (AnyInterestingYet)
+ return false;
+ AnyInterestingYet = true;
+ }
+ return AnyInterestingYet;
}
// Nothing else is interesting here.
// Get the symbolic expression for this instruction.
const SCEV *ISE = SE->getSCEV(I);
- if (isa<SCEVCouldNotCompute>(ISE)) return false;
// If we've come to an uninteresting expression, stop the traversal and
// call this a user.
- if (!isInteresting(ISE, I, L))
+ if (!isInteresting(ISE, I, L, SE))
return false;
SmallPtrSet<Instruction *, 4> UniqueUsers;
if (AddUserToIVUsers) {
// Okay, we found a user that we cannot reduce.
- IVUses.push_back(new IVStrideUse(this, ISE, User, I));
+ IVUses.push_back(new IVStrideUse(this, User, I));
IVStrideUse &NewUse = IVUses.back();
// Transform the expression into a normalized form.
- NewUse.Expr =
- TransformForPostIncUse(NormalizeAutodetect, NewUse.Expr,
- User, I,
- NewUse.PostIncLoops,
- *SE, *DT);
- DEBUG(dbgs() << " NORMALIZED TO: " << *NewUse.Expr << '\n');
+ ISE = TransformForPostIncUse(NormalizeAutodetect,
+ ISE, User, I,
+ NewUse.PostIncLoops,
+ *SE, *DT);
+ DEBUG(dbgs() << " NORMALIZED TO: " << *ISE << '\n');
}
}
return true;
}
-IVStrideUse &IVUsers::AddUser(const SCEV *Expr,
- Instruction *User, Value *Operand) {
- IVUses.push_back(new IVStrideUse(this, Expr, User, Operand));
+IVStrideUse &IVUsers::AddUser(Instruction *User, Value *Operand) {
+ IVUses.push_back(new IVStrideUse(this, User, Operand));
return IVUses.back();
}
IVUsers::IVUsers()
- : LoopPass(&ID) {
+ : LoopPass(ID) {
+ initializeIVUsersPass(*PassRegistry::getPassRegistry());
}
void IVUsers::getAnalysisUsage(AnalysisUsage &AU) const {
// them by stride. Start by finding all of the PHI nodes in the header for
// this loop. If they are induction variables, inspect their uses.
for (BasicBlock::iterator I = L->getHeader()->begin(); isa<PHINode>(I); ++I)
- AddUsersIfInteresting(I);
+ (void)AddUsersIfInteresting(I);
return false;
}
-/// getReplacementExpr - Return a SCEV expression which computes the
-/// value of the OperandValToReplace of the given IVStrideUse.
-const SCEV *IVUsers::getReplacementExpr(const IVStrideUse &U) const {
- PostIncLoopSet &Loops = const_cast<PostIncLoopSet &>(U.PostIncLoops);
- return TransformForPostIncUse(Denormalize, U.getExpr(),
- U.getUser(), U.getOperandValToReplace(),
- Loops, *SE, *DT);
-}
-
void IVUsers::print(raw_ostream &OS, const Module *M) const {
OS << "IV Users for loop ";
WriteAsOperand(OS, L->getHeader(), false);
}
OS << ":\n";
- // Use a default AssemblyAnnotationWriter to suppress the default info
- // comments, which aren't relevant here.
- AssemblyAnnotationWriter Annotator;
for (ilist<IVStrideUse>::const_iterator UI = IVUses.begin(),
E = IVUses.end(); UI != E; ++UI) {
OS << " ";
WriteAsOperand(OS, UI->getOperandValToReplace(), false);
- OS << " = "
- << *getReplacementExpr(*UI);
+ OS << " = " << *getReplacementExpr(*UI);
for (PostIncLoopSet::const_iterator
I = UI->PostIncLoops.begin(),
E = UI->PostIncLoops.end(); I != E; ++I) {
OS << ")";
}
OS << " in ";
- UI->getUser()->print(OS, &Annotator);
+ UI->getUser()->print(OS);
OS << '\n';
}
}
IVUses.clear();
}
+/// getReplacementExpr - Return a SCEV expression which computes the
+/// value of the OperandValToReplace.
+const SCEV *IVUsers::getReplacementExpr(const IVStrideUse &IU) const {
+ return SE->getSCEV(IU.getOperandValToReplace());
+}
+
+/// getExpr - Return the expression for the use.
+const SCEV *IVUsers::getExpr(const IVStrideUse &IU) const {
+ return
+ TransformForPostIncUse(Normalize, getReplacementExpr(IU),
+ IU.getUser(), IU.getOperandValToReplace(),
+ const_cast<PostIncLoopSet &>(IU.getPostIncLoops()),
+ *SE, *DT);
+}
+
static const SCEVAddRecExpr *findAddRecForLoop(const SCEV *S, const Loop *L) {
if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S)) {
if (AR->getLoop() == L)
return 0;
}
-const SCEV *IVStrideUse::getStride(const Loop *L) const {
- if (const SCEVAddRecExpr *AR = findAddRecForLoop(getExpr(), L))
- return AR->getStepRecurrence(*Parent->SE);
+const SCEV *IVUsers::getStride(const IVStrideUse &IU, const Loop *L) const {
+ if (const SCEVAddRecExpr *AR = findAddRecForLoop(getExpr(IU), L))
+ return AR->getStepRecurrence(*SE);
return 0;
}
void IVStrideUse::transformToPostInc(const Loop *L) {
- PostIncLoopSet Loops;
- Loops.insert(L);
- Expr = TransformForPostIncUse(Normalize, Expr,
- getUser(), getOperandValToReplace(),
- Loops, *Parent->SE, *Parent->DT);
PostIncLoops.insert(L);
}
projects / oota-llvm.git / blobdiff