[llvm-commits] [llvm] r77032 - in /llvm/trunk: include/llvm/Analysis/ScalarEvolution.h include/llvm/Analysis/ScalarEvolutionExpressions.h lib/Analysis/ScalarEvolution.cpp
Dan Gohman
gohman at apple.com
Fri Jul 24 18:13:03 PDT 2009
Author: djg
Date: Fri Jul 24 20:13:03 2009
New Revision: 77032
URL: http://llvm.org/viewvc/llvm-project?rev=77032&view=rev
Log:
Instead of eagerly creating new SCEVs to replace all SCEVs that are
affected after a PHI node has been analyzed, just remove affected
SCEVs from the Scalars map, so that they'll be (lazily) recreated as
needed. This avoids creating SCEV objects that aren't actually needed.
Also, rewrite the associated def-use walking code to be non-recursive
and to continue traversing past Instructions that don't have an
entry in the Scalars map.
Modified:
llvm/trunk/include/llvm/Analysis/ScalarEvolution.h
llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpressions.h
llvm/trunk/lib/Analysis/ScalarEvolution.cpp
Modified: llvm/trunk/include/llvm/Analysis/ScalarEvolution.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/ScalarEvolution.h?rev=77032&r1=77031&r2=77032&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/ScalarEvolution.h (original)
+++ llvm/trunk/include/llvm/Analysis/ScalarEvolution.h Fri Jul 24 20:13:03 2009
@@ -96,15 +96,9 @@
///
bool isAllOnesValue() const;
- /// replaceSymbolicValuesWithConcrete - If this SCEV internally references
- /// the symbolic value "Sym", construct and return a new SCEV that produces
- /// the same value, but which uses the concrete value Conc instead of the
- /// symbolic value. If this SCEV does not use the symbolic value, it
- /// returns itself.
- virtual const SCEV *
- replaceSymbolicValuesWithConcrete(const SCEV *Sym,
- const SCEV *Conc,
- ScalarEvolution &SE) const = 0;
+ /// hasOperand - Test whether this SCEV has Op as a direct or
+ /// indirect operand.
+ virtual bool hasOperand(const SCEV *Op) const = 0;
/// dominates - Return true if elements that makes up this SCEV dominates
/// the specified basic block.
@@ -145,10 +139,7 @@
virtual const Type *getType() const;
virtual bool hasComputableLoopEvolution(const Loop *L) const;
virtual void print(raw_ostream &OS) const;
- virtual const SCEV *
- replaceSymbolicValuesWithConcrete(const SCEV *Sym,
- const SCEV *Conc,
- ScalarEvolution &SE) const;
+ virtual bool hasOperand(const SCEV *Op) const;
virtual bool dominates(BasicBlock *BB, DominatorTree *DT) const {
return true;
@@ -252,13 +243,11 @@
/// SCEVs.
const SCEV *createNodeForGEP(Operator *GEP);
- /// ReplaceSymbolicValueWithConcrete - This looks up the computed SCEV value
- /// for the specified instruction and replaces any references to the
- /// symbolic value SymName with the specified value. This is used during
- /// PHI resolution.
- void ReplaceSymbolicValueWithConcrete(Instruction *I,
- const SCEV *SymName,
- const SCEV *NewVal);
+ /// ForgetSymbolicValue - This looks up computed SCEV values for all
+ /// instructions that depend on the given instruction and removes them from
+ /// the Scalars map if they reference SymName. This is used during PHI
+ /// resolution.
+ void ForgetSymbolicName(Instruction *I, const SCEV *SymName);
/// getBECount - Subtract the end and start values and divide by the step,
/// rounding up, to get the number of times the backedge is executed. Return
Modified: llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpressions.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpressions.h?rev=77032&r1=77031&r2=77032&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpressions.h (original)
+++ llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpressions.h Fri Jul 24 20:13:03 2009
@@ -52,10 +52,8 @@
virtual const Type *getType() const;
- const SCEV *replaceSymbolicValuesWithConcrete(const SCEV *Sym,
- const SCEV *Conc,
- ScalarEvolution &SE) const {
- return this;
+ virtual bool hasOperand(const SCEV *) const {
+ return false;
}
bool dominates(BasicBlock *BB, DominatorTree *DT) const {
@@ -94,6 +92,10 @@
return Op->hasComputableLoopEvolution(L);
}
+ virtual bool hasOperand(const SCEV *O) const {
+ return Op == O || Op->hasOperand(O);
+ }
+
virtual bool dominates(BasicBlock *BB, DominatorTree *DT) const;
/// Methods for support type inquiry through isa, cast, and dyn_cast:
@@ -116,15 +118,6 @@
const SCEV *op, const Type *ty);
public:
- const SCEV *replaceSymbolicValuesWithConcrete(const SCEV *Sym,
- const SCEV *Conc,
- ScalarEvolution &SE) const {
- const SCEV *H = Op->replaceSymbolicValuesWithConcrete(Sym, Conc, SE);
- if (H == Op)
- return this;
- return SE.getTruncateExpr(H, Ty);
- }
-
virtual void print(raw_ostream &OS) const;
/// Methods for support type inquiry through isa, cast, and dyn_cast:
@@ -145,15 +138,6 @@
const SCEV *op, const Type *ty);
public:
- const SCEV *replaceSymbolicValuesWithConcrete(const SCEV *Sym,
- const SCEV *Conc,
- ScalarEvolution &SE) const {
- const SCEV *H = Op->replaceSymbolicValuesWithConcrete(Sym, Conc, SE);
- if (H == Op)
- return this;
- return SE.getZeroExtendExpr(H, Ty);
- }
-
virtual void print(raw_ostream &OS) const;
/// Methods for support type inquiry through isa, cast, and dyn_cast:
@@ -174,15 +158,6 @@
const SCEV *op, const Type *ty);
public:
- const SCEV *replaceSymbolicValuesWithConcrete(const SCEV *Sym,
- const SCEV *Conc,
- ScalarEvolution &SE) const {
- const SCEV *H = Op->replaceSymbolicValuesWithConcrete(Sym, Conc, SE);
- if (H == Op)
- return this;
- return SE.getSignExtendExpr(H, Ty);
- }
-
virtual void print(raw_ostream &OS) const;
/// Methods for support type inquiry through isa, cast, and dyn_cast:
@@ -240,6 +215,13 @@
return HasVarying;
}
+ virtual bool hasOperand(const SCEV *O) const {
+ for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
+ if (O == getOperand(i) || getOperand(i)->hasOperand(O))
+ return true;
+ return false;
+ }
+
bool dominates(BasicBlock *BB, DominatorTree *DT) const;
virtual const Type *getType() const { return getOperand(0)->getType(); }
@@ -267,10 +249,6 @@
: SCEVNAryExpr(ID, T, ops) {}
public:
- const SCEV *replaceSymbolicValuesWithConcrete(const SCEV *Sym,
- const SCEV *Conc,
- ScalarEvolution &SE) const;
-
virtual const char *getOperationStr() const = 0;
virtual void print(raw_ostream &OS) const;
@@ -353,15 +331,8 @@
RHS->hasComputableLoopEvolution(L);
}
- const SCEV *replaceSymbolicValuesWithConcrete(const SCEV *Sym,
- const SCEV *Conc,
- ScalarEvolution &SE) const {
- const SCEV *L = LHS->replaceSymbolicValuesWithConcrete(Sym, Conc, SE);
- const SCEV *R = RHS->replaceSymbolicValuesWithConcrete(Sym, Conc, SE);
- if (L == LHS && R == RHS)
- return this;
- else
- return SE.getUDivExpr(L, R);
+ virtual bool hasOperand(const SCEV *O) const {
+ return O == LHS || O == RHS || LHS->hasOperand(O) || RHS->hasOperand(O);
}
bool dominates(BasicBlock *BB, DominatorTree *DT) const;
@@ -449,14 +420,10 @@
const SCEV *getNumIterationsInRange(ConstantRange Range,
ScalarEvolution &SE) const;
- const SCEV *replaceSymbolicValuesWithConcrete(const SCEV *Sym,
- const SCEV *Conc,
- ScalarEvolution &SE) const;
-
/// getPostIncExpr - Return an expression representing the value of
/// this expression one iteration of the loop ahead.
- const SCEV *getPostIncExpr(ScalarEvolution &SE) const {
- return SE.getAddExpr(this, getStepRecurrence(SE));
+ const SCEVAddRecExpr *getPostIncExpr(ScalarEvolution &SE) const {
+ return cast<SCEVAddRecExpr>(SE.getAddExpr(this, getStepRecurrence(SE)));
}
bool hasNoUnsignedOverflow() const { return SubclassData & (1 << 0); }
@@ -542,11 +509,8 @@
return false; // not computable
}
- const SCEV *replaceSymbolicValuesWithConcrete(const SCEV *Sym,
- const SCEV *Conc,
- ScalarEvolution &SE) const {
- if (&*Sym == this) return Conc;
- return this;
+ virtual bool hasOperand(const SCEV *) const {
+ return false;
}
bool dominates(BasicBlock *BB, DominatorTree *DT) const;
Modified: llvm/trunk/lib/Analysis/ScalarEvolution.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ScalarEvolution.cpp?rev=77032&r1=77031&r2=77032&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ScalarEvolution.cpp (original)
+++ llvm/trunk/lib/Analysis/ScalarEvolution.cpp Fri Jul 24 20:13:03 2009
@@ -163,12 +163,9 @@
return false;
}
-const SCEV *
-SCEVCouldNotCompute::replaceSymbolicValuesWithConcrete(
- const SCEV *Sym,
- const SCEV *Conc,
- ScalarEvolution &SE) const {
- return this;
+bool SCEVCouldNotCompute::hasOperand(const SCEV *) const {
+ llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!");
+ return false;
}
void SCEVCouldNotCompute::print(raw_ostream &OS) const {
@@ -260,39 +257,6 @@
OS << ")";
}
-const SCEV *
-SCEVCommutativeExpr::replaceSymbolicValuesWithConcrete(
- const SCEV *Sym,
- const SCEV *Conc,
- ScalarEvolution &SE) const {
- for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
- const SCEV *H =
- getOperand(i)->replaceSymbolicValuesWithConcrete(Sym, Conc, SE);
- if (H != getOperand(i)) {
- SmallVector<const SCEV *, 8> NewOps;
- NewOps.reserve(getNumOperands());
- for (unsigned j = 0; j != i; ++j)
- NewOps.push_back(getOperand(j));
- NewOps.push_back(H);
- for (++i; i != e; ++i)
- NewOps.push_back(getOperand(i)->
- replaceSymbolicValuesWithConcrete(Sym, Conc, SE));
-
- if (isa<SCEVAddExpr>(this))
- return SE.getAddExpr(NewOps);
- else if (isa<SCEVMulExpr>(this))
- return SE.getMulExpr(NewOps);
- else if (isa<SCEVSMaxExpr>(this))
- return SE.getSMaxExpr(NewOps);
- else if (isa<SCEVUMaxExpr>(this))
- return SE.getUMaxExpr(NewOps);
- else
- llvm_unreachable("Unknown commutative expr!");
- }
- }
- return this;
-}
-
bool SCEVNAryExpr::dominates(BasicBlock *BB, DominatorTree *DT) const {
for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
if (!getOperand(i)->dominates(BB, DT))
@@ -318,30 +282,6 @@
return RHS->getType();
}
-const SCEV *
-SCEVAddRecExpr::replaceSymbolicValuesWithConcrete(const SCEV *Sym,
- const SCEV *Conc,
- ScalarEvolution &SE) const {
- for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
- const SCEV *H =
- getOperand(i)->replaceSymbolicValuesWithConcrete(Sym, Conc, SE);
- if (H != getOperand(i)) {
- SmallVector<const SCEV *, 8> NewOps;
- NewOps.reserve(getNumOperands());
- for (unsigned j = 0; j != i; ++j)
- NewOps.push_back(getOperand(j));
- NewOps.push_back(H);
- for (++i; i != e; ++i)
- NewOps.push_back(getOperand(i)->
- replaceSymbolicValuesWithConcrete(Sym, Conc, SE));
-
- return SE.getAddRecExpr(NewOps, L);
- }
- }
- return this;
-}
-
-
bool SCEVAddRecExpr::isLoopInvariant(const Loop *QueryLoop) const {
// Add recurrences are never invariant in the function-body (null loop).
if (!QueryLoop)
@@ -2301,28 +2241,53 @@
return getUMinExpr(PromotedLHS, PromotedRHS);
}
-/// ReplaceSymbolicValueWithConcrete - This looks up the computed SCEV value for
-/// the specified instruction and replaces any references to the symbolic value
-/// SymName with the specified value. This is used during PHI resolution.
+/// PushDefUseChildren - Push users of the given Instruction
+/// onto the given Worklist.
+static void
+PushDefUseChildren(Instruction *I,
+ SmallVectorImpl<Instruction *> &Worklist) {
+ // Push the def-use children onto the Worklist stack.
+ for (Value::use_iterator UI = I->use_begin(), UE = I->use_end();
+ UI != UE; ++UI)
+ Worklist.push_back(cast<Instruction>(UI));
+}
+
+/// ForgetSymbolicValue - This looks up computed SCEV values for all
+/// instructions that depend on the given instruction and removes them from
+/// the Scalars map if they reference SymName. This is used during PHI
+/// resolution.
void
-ScalarEvolution::ReplaceSymbolicValueWithConcrete(Instruction *I,
- const SCEV *SymName,
- const SCEV *NewVal) {
- std::map<SCEVCallbackVH, const SCEV *>::iterator SI =
- Scalars.find(SCEVCallbackVH(I, this));
- if (SI == Scalars.end()) return;
-
- const SCEV *NV =
- SI->second->replaceSymbolicValuesWithConcrete(SymName, NewVal, *this);
- if (NV == SI->second) return; // No change.
-
- SI->second = NV; // Update the scalars map!
-
- // Any instruction values that use this instruction might also need to be
- // updated!
- for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
- UI != E; ++UI)
- ReplaceSymbolicValueWithConcrete(cast<Instruction>(*UI), SymName, NewVal);
+ScalarEvolution::ForgetSymbolicName(Instruction *I, const SCEV *SymName) {
+ SmallVector<Instruction *, 16> Worklist;
+ PushDefUseChildren(I, Worklist);
+
+ SmallPtrSet<Instruction *, 8> Visited;
+ Visited.insert(I);
+ while (!Worklist.empty()) {
+ Instruction *I = Worklist.pop_back_val();
+ if (!Visited.insert(I)) continue;
+
+ std::map<SCEVCallbackVH, const SCEV*>::iterator It =
+ Scalars.find(static_cast<Value *>(I));
+ if (It != Scalars.end()) {
+ // Short-circuit the def-use traversal if the symbolic name
+ // ceases to appear in expressions.
+ if (!It->second->hasOperand(SymName))
+ continue;
+
+ // SCEVUnknown for a PHI either means that it has an unrecognized
+ // structure, or it's a PHI that's in the progress of being computed
+ // by createNodeForPHI. In the former case, additional loop trip
+ // count information isn't going to change anything. In the later
+ // case, createNodeForPHI will perform the necessary updates on its
+ // own when it gets to that point.
+ if (!isa<PHINode>(I) || !isa<SCEVUnknown>(It->second))
+ Scalars.erase(It);
+ ValuesAtScopes.erase(I);
+ }
+
+ PushDefUseChildren(I, Worklist);
+ }
}
/// createNodeForPHI - PHI nodes have two cases. Either the PHI node exists in
@@ -2345,7 +2310,8 @@
// Using this symbolic name for the PHI, analyze the value coming around
// the back-edge.
- const SCEV *BEValue = getSCEV(PN->getIncomingValue(BackEdge));
+ Value *BEValueV = PN->getIncomingValue(BackEdge);
+ const SCEV *BEValue = getSCEV(BEValueV);
// NOTE: If BEValue is loop invariant, we know that the PHI node just
// has a special value for the first iteration of the loop.
@@ -2382,11 +2348,10 @@
getAddRecExpr(StartVal, Accum, L);
// Okay, for the entire analysis of this edge we assumed the PHI
- // to be symbolic. We now need to go back and update all of the
- // entries for the scalars that use the PHI (except for the PHI
- // itself) to use the new analyzed value instead of the "symbolic"
- // value.
- ReplaceSymbolicValueWithConcrete(PN, SymbolicName, PHISCEV);
+ // to be symbolic. We now need to go back and purge all of the
+ // entries for the scalars that use the symbolic expression.
+ ForgetSymbolicName(PN, SymbolicName);
+ Scalars[SCEVCallbackVH(PN, this)] = PHISCEV;
return PHISCEV;
}
}
@@ -2408,11 +2373,10 @@
getAddRecExpr(StartVal, AddRec->getOperand(1), L);
// Okay, for the entire analysis of this edge we assumed the PHI
- // to be symbolic. We now need to go back and update all of the
- // entries for the scalars that use the PHI (except for the PHI
- // itself) to use the new analyzed value instead of the "symbolic"
- // value.
- ReplaceSymbolicValueWithConcrete(PN, SymbolicName, PHISCEV);
+ // to be symbolic. We now need to go back and purge all of the
+ // entries for the scalars that use the symbolic expression.
+ ForgetSymbolicName(PN, SymbolicName);
+ Scalars[SCEVCallbackVH(PN, this)] = PHISCEV;
return PHISCEV;
}
}
@@ -3058,17 +3022,6 @@
Worklist.push_back(PN);
}
-/// PushDefUseChildren - Push users of the given Instruction
-/// onto the given Worklist.
-static void
-PushDefUseChildren(Instruction *I,
- SmallVectorImpl<Instruction *> &Worklist) {
- // Push the def-use children onto the Worklist stack.
- for (Value::use_iterator UI = I->use_begin(), UE = I->use_end();
- UI != UE; ++UI)
- Worklist.push_back(cast<Instruction>(UI));
-}
-
const ScalarEvolution::BackedgeTakenInfo &
ScalarEvolution::getBackedgeTakenInfo(const Loop *L) {
// Initially insert a CouldNotCompute for this loop. If the insertion
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