[llvm] r302550 - NewGVN: Make all of symbolic evaluation logically const.
Daniel Berlin via llvm-commits
llvm-commits at lists.llvm.org
Tue May 9 09:40:05 PDT 2017
Author: dannyb
Date: Tue May 9 11:40:04 2017
New Revision: 302550
URL: http://llvm.org/viewvc/llvm-project?rev=302550&view=rev
Log:
NewGVN: Make all of symbolic evaluation logically const.
Modified:
llvm/trunk/lib/Transforms/Scalar/NewGVN.cpp
Modified: llvm/trunk/lib/Transforms/Scalar/NewGVN.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/NewGVN.cpp?rev=302550&r1=302549&r2=302550&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/NewGVN.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/NewGVN.cpp Tue May 9 11:40:04 2017
@@ -401,9 +401,12 @@ class NewGVN {
MemorySSAWalker *MSSAWalker;
const DataLayout &DL;
std::unique_ptr<PredicateInfo> PredInfo;
- BumpPtrAllocator ExpressionAllocator;
- ArrayRecycler<Value *> ArgRecycler;
- TarjanSCC SCCFinder;
+
+ // These are the only two things the create* functions should have
+ // side-effects on due to allocating memory.
+ mutable BumpPtrAllocator ExpressionAllocator;
+ mutable ArrayRecycler<Value *> ArgRecycler;
+ mutable TarjanSCC SCCFinder;
const SimplifyQuery SQ;
// Number of function arguments, used by ranking
@@ -430,11 +433,12 @@ class NewGVN {
// In order to correctly ensure propagation, we must keep track of what
// comparisons we used, so that when the values of the comparisons change, we
// propagate the information to the places we used the comparison.
- DenseMap<const Value *, SmallPtrSet<Instruction *, 2>> PredicateToUsers;
- // Mapping from MemoryAccess we used to the MemoryAccess we used it with. Has
+ mutable DenseMap<const Value *, SmallPtrSet<Instruction *, 2>>
+ PredicateToUsers;
// the same reasoning as PredicateToUsers. When we skip MemoryAccesses for
// stores, we no longer can rely solely on the def-use chains of MemorySSA.
- DenseMap<const MemoryAccess *, SmallPtrSet<MemoryAccess *, 2>> MemoryToUsers;
+ mutable DenseMap<const MemoryAccess *, SmallPtrSet<MemoryAccess *, 2>>
+ MemoryToUsers;
// A table storing which memorydefs/phis represent a memory state provably
// equivalent to another memory state.
@@ -457,7 +461,7 @@ class NewGVN {
DenseMap<const MemoryPhi *, MemoryPhiState> MemoryPhiState;
enum PhiCycleState { PCS_Unknown, PCS_CycleFree, PCS_Cycle };
- DenseMap<const PHINode *, PhiCycleState> PhiCycleState;
+ mutable DenseMap<const PHINode *, PhiCycleState> PhiCycleState;
// Expression to class mapping.
using ExpressionClassMap = DenseMap<const Expression *, CongruenceClass *>;
ExpressionClassMap ExpressionToClass;
@@ -511,21 +515,24 @@ public:
private:
// Expression handling.
- const Expression *createExpression(Instruction *);
- const Expression *createBinaryExpression(unsigned, Type *, Value *, Value *);
- PHIExpression *createPHIExpression(Instruction *, bool &HasBackedge,
- bool &AllConstant);
- const VariableExpression *createVariableExpression(Value *);
- const ConstantExpression *createConstantExpression(Constant *);
- const Expression *createVariableOrConstant(Value *V);
- const UnknownExpression *createUnknownExpression(Instruction *);
+ const Expression *createExpression(Instruction *) const;
+ const Expression *createBinaryExpression(unsigned, Type *, Value *,
+ Value *) const;
+ PHIExpression *createPHIExpression(Instruction *, bool &HasBackEdge,
+ bool &AllConstant) const;
+ const VariableExpression *createVariableExpression(Value *) const;
+ const ConstantExpression *createConstantExpression(Constant *) const;
+ const Expression *createVariableOrConstant(Value *V) const;
+ const UnknownExpression *createUnknownExpression(Instruction *) const;
const StoreExpression *createStoreExpression(StoreInst *,
- const MemoryAccess *);
+ const MemoryAccess *) const;
LoadExpression *createLoadExpression(Type *, Value *, LoadInst *,
- const MemoryAccess *);
- const CallExpression *createCallExpression(CallInst *, const MemoryAccess *);
- const AggregateValueExpression *createAggregateValueExpression(Instruction *);
- bool setBasicExpressionInfo(Instruction *, BasicExpression *);
+ const MemoryAccess *) const;
+ const CallExpression *createCallExpression(CallInst *,
+ const MemoryAccess *) const;
+ const AggregateValueExpression *
+ createAggregateValueExpression(Instruction *) const;
+ bool setBasicExpressionInfo(Instruction *, BasicExpression *) const;
// Congruence class handling.
CongruenceClass *createCongruenceClass(Value *Leader, const Expression *E) {
@@ -560,17 +567,18 @@ private:
// Symbolic evaluation.
const Expression *checkSimplificationResults(Expression *, Instruction *,
- Value *);
- const Expression *performSymbolicEvaluation(Value *);
+ Value *) const;
+ const Expression *performSymbolicEvaluation(Value *) const;
const Expression *performSymbolicLoadCoercion(Type *, Value *, LoadInst *,
- Instruction *, MemoryAccess *);
- const Expression *performSymbolicLoadEvaluation(Instruction *);
- const Expression *performSymbolicStoreEvaluation(Instruction *);
- const Expression *performSymbolicCallEvaluation(Instruction *);
- const Expression *performSymbolicPHIEvaluation(Instruction *);
- const Expression *performSymbolicAggrValueEvaluation(Instruction *);
- const Expression *performSymbolicCmpEvaluation(Instruction *);
- const Expression *performSymbolicPredicateInfoEvaluation(Instruction *);
+ Instruction *,
+ MemoryAccess *) const;
+ const Expression *performSymbolicLoadEvaluation(Instruction *) const;
+ const Expression *performSymbolicStoreEvaluation(Instruction *) const;
+ const Expression *performSymbolicCallEvaluation(Instruction *) const;
+ const Expression *performSymbolicPHIEvaluation(Instruction *) const;
+ const Expression *performSymbolicAggrValueEvaluation(Instruction *) const;
+ const Expression *performSymbolicCmpEvaluation(Instruction *) const;
+ const Expression *performSymbolicPredicateInfoEvaluation(Instruction *) const;
// Congruence finding.
bool someEquivalentDominates(const Instruction *, const Instruction *) const;
@@ -620,8 +628,8 @@ private:
void markPredicateUsersTouched(Instruction *);
void markValueLeaderChangeTouched(CongruenceClass *CC);
void markMemoryLeaderChangeTouched(CongruenceClass *CC);
- void addPredicateUsers(const PredicateBase *, Instruction *);
- void addMemoryUsers(const MemoryAccess *To, MemoryAccess *U);
+ void addPredicateUsers(const PredicateBase *, Instruction *) const;
+ void addMemoryUsers(const MemoryAccess *To, MemoryAccess *U) const;
// Main loop of value numbering
void iterateTouchedInstructions();
@@ -634,7 +642,7 @@ private:
void verifyIterationSettled(Function &F);
bool singleReachablePHIPath(const MemoryAccess *, const MemoryAccess *) const;
BasicBlock *getBlockForValue(Value *V) const;
- void deleteExpression(const Expression *E);
+ void deleteExpression(const Expression *E) const;
unsigned InstrToDFSNum(const Value *V) const {
assert(isa<Instruction>(V) && "This should not be used for MemoryAccesses");
return InstrDFS.lookup(V);
@@ -654,7 +662,7 @@ private:
? InstrToDFSNum(cast<MemoryUseOrDef>(MA)->getMemoryInst())
: InstrDFS.lookup(MA);
}
- bool isCycleFree(const PHINode *PN);
+ bool isCycleFree(const PHINode *PN) const ;
template <class T, class Range> T *getMinDFSOfRange(const Range &) const;
// Debug counter info. When verifying, we have to reset the value numbering
// debug counter to the same state it started in to get the same results.
@@ -702,7 +710,7 @@ BasicBlock *NewGVN::getBlockForValue(Val
// Delete a definitely dead expression, so it can be reused by the expression
// allocator. Some of these are not in creation functions, so we have to accept
// const versions.
-void NewGVN::deleteExpression(const Expression *E) {
+void NewGVN::deleteExpression(const Expression *E) const {
assert(isa<BasicExpression>(E));
auto *BE = cast<BasicExpression>(E);
const_cast<BasicExpression *>(BE)->deallocateOperands(ArgRecycler);
@@ -710,7 +718,7 @@ void NewGVN::deleteExpression(const Expr
}
PHIExpression *NewGVN::createPHIExpression(Instruction *I, bool &HasBackedge,
- bool &AllConstant) {
+ bool &AllConstant) const {
BasicBlock *PHIBlock = I->getParent();
auto *PN = cast<PHINode>(I);
auto *E =
@@ -745,7 +753,7 @@ PHIExpression *NewGVN::createPHIExpressi
// Set basic expression info (Arguments, type, opcode) for Expression
// E from Instruction I in block B.
-bool NewGVN::setBasicExpressionInfo(Instruction *I, BasicExpression *E) {
+bool NewGVN::setBasicExpressionInfo(Instruction *I, BasicExpression *E) const {
bool AllConstant = true;
if (auto *GEP = dyn_cast<GetElementPtrInst>(I))
E->setType(GEP->getSourceElementType());
@@ -766,7 +774,8 @@ bool NewGVN::setBasicExpressionInfo(Inst
}
const Expression *NewGVN::createBinaryExpression(unsigned Opcode, Type *T,
- Value *Arg1, Value *Arg2) {
+ Value *Arg1,
+ Value *Arg2) const {
auto *E = new (ExpressionAllocator) BasicExpression(2);
E->setType(T);
@@ -795,7 +804,8 @@ const Expression *NewGVN::createBinaryEx
// TODO: Once finished, this should not take an Instruction, we only
// use it for printing.
const Expression *NewGVN::checkSimplificationResults(Expression *E,
- Instruction *I, Value *V) {
+ Instruction *I,
+ Value *V) const {
if (!V)
return nullptr;
if (auto *C = dyn_cast<Constant>(V)) {
@@ -827,7 +837,7 @@ const Expression *NewGVN::checkSimplific
return nullptr;
}
-const Expression *NewGVN::createExpression(Instruction *I) {
+const Expression *NewGVN::createExpression(Instruction *I) const {
auto *E = new (ExpressionAllocator) BasicExpression(I->getNumOperands());
bool AllConstant = setBasicExpressionInfo(I, E);
@@ -913,7 +923,7 @@ const Expression *NewGVN::createExpressi
}
const AggregateValueExpression *
-NewGVN::createAggregateValueExpression(Instruction *I) {
+NewGVN::createAggregateValueExpression(Instruction *I) const {
if (auto *II = dyn_cast<InsertValueInst>(I)) {
auto *E = new (ExpressionAllocator)
AggregateValueExpression(I->getNumOperands(), II->getNumIndices());
@@ -932,32 +942,32 @@ NewGVN::createAggregateValueExpression(I
llvm_unreachable("Unhandled type of aggregate value operation");
}
-const VariableExpression *NewGVN::createVariableExpression(Value *V) {
+const VariableExpression *NewGVN::createVariableExpression(Value *V) const {
auto *E = new (ExpressionAllocator) VariableExpression(V);
E->setOpcode(V->getValueID());
return E;
}
-const Expression *NewGVN::createVariableOrConstant(Value *V) {
+const Expression *NewGVN::createVariableOrConstant(Value *V) const {
if (auto *C = dyn_cast<Constant>(V))
return createConstantExpression(C);
return createVariableExpression(V);
}
-const ConstantExpression *NewGVN::createConstantExpression(Constant *C) {
+const ConstantExpression *NewGVN::createConstantExpression(Constant *C) const {
auto *E = new (ExpressionAllocator) ConstantExpression(C);
E->setOpcode(C->getValueID());
return E;
}
-const UnknownExpression *NewGVN::createUnknownExpression(Instruction *I) {
+const UnknownExpression *NewGVN::createUnknownExpression(Instruction *I) const {
auto *E = new (ExpressionAllocator) UnknownExpression(I);
E->setOpcode(I->getOpcode());
return E;
}
-const CallExpression *NewGVN::createCallExpression(CallInst *CI,
- const MemoryAccess *MA) {
+const CallExpression *
+NewGVN::createCallExpression(CallInst *CI, const MemoryAccess *MA) const {
// FIXME: Add operand bundles for calls.
auto *E =
new (ExpressionAllocator) CallExpression(CI->getNumOperands(), CI, MA);
@@ -1032,7 +1042,7 @@ bool NewGVN::isMemoryAccessTop(const Mem
LoadExpression *NewGVN::createLoadExpression(Type *LoadType, Value *PointerOp,
LoadInst *LI,
- const MemoryAccess *MA) {
+ const MemoryAccess *MA) const {
auto *E =
new (ExpressionAllocator) LoadExpression(1, LI, lookupMemoryLeader(MA));
E->allocateOperands(ArgRecycler, ExpressionAllocator);
@@ -1050,8 +1060,8 @@ LoadExpression *NewGVN::createLoadExpres
return E;
}
-const StoreExpression *NewGVN::createStoreExpression(StoreInst *SI,
- const MemoryAccess *MA) {
+const StoreExpression *
+NewGVN::createStoreExpression(StoreInst *SI, const MemoryAccess *MA) const {
auto *StoredValueLeader = lookupOperandLeader(SI->getValueOperand());
auto *E = new (ExpressionAllocator)
StoreExpression(SI->getNumOperands(), SI, StoredValueLeader, MA);
@@ -1068,7 +1078,7 @@ const StoreExpression *NewGVN::createSto
return E;
}
-const Expression *NewGVN::performSymbolicStoreEvaluation(Instruction *I) {
+const Expression *NewGVN::performSymbolicStoreEvaluation(Instruction *I) const {
// Unlike loads, we never try to eliminate stores, so we do not check if they
// are simple and avoid value numbering them.
auto *SI = cast<StoreInst>(I);
@@ -1126,7 +1136,7 @@ const Expression *NewGVN::performSymboli
const Expression *
NewGVN::performSymbolicLoadCoercion(Type *LoadType, Value *LoadPtr,
LoadInst *LI, Instruction *DepInst,
- MemoryAccess *DefiningAccess) {
+ MemoryAccess *DefiningAccess) const {
assert((!LI || LI->isSimple()) && "Not a simple load");
if (auto *DepSI = dyn_cast<StoreInst>(DepInst)) {
// Can't forward from non-atomic to atomic without violating memory model.
@@ -1201,7 +1211,7 @@ NewGVN::performSymbolicLoadCoercion(Type
return nullptr;
}
-const Expression *NewGVN::performSymbolicLoadEvaluation(Instruction *I) {
+const Expression *NewGVN::performSymbolicLoadEvaluation(Instruction *I) const {
auto *LI = cast<LoadInst>(I);
// We can eliminate in favor of non-simple loads, but we won't be able to
@@ -1239,7 +1249,7 @@ const Expression *NewGVN::performSymboli
}
const Expression *
-NewGVN::performSymbolicPredicateInfoEvaluation(Instruction *I) {
+NewGVN::performSymbolicPredicateInfoEvaluation(Instruction *I) const {
auto *PI = PredInfo->getPredicateInfoFor(I);
if (!PI)
return nullptr;
@@ -1329,7 +1339,7 @@ NewGVN::performSymbolicPredicateInfoEval
}
// Evaluate read only and pure calls, and create an expression result.
-const Expression *NewGVN::performSymbolicCallEvaluation(Instruction *I) {
+const Expression *NewGVN::performSymbolicCallEvaluation(Instruction *I) const {
auto *CI = cast<CallInst>(I);
if (auto *II = dyn_cast<IntrinsicInst>(I)) {
// Instrinsics with the returned attribute are copies of arguments.
@@ -1406,7 +1416,7 @@ bool NewGVN::setMemoryClass(const Memory
// Determine if a phi is cycle-free. That means the values in the phi don't
// depend on any expressions that can change value as a result of the phi.
// For example, a non-cycle free phi would be v = phi(0, v+1).
-bool NewGVN::isCycleFree(const PHINode *PN) {
+bool NewGVN::isCycleFree(const PHINode *PN) const {
// In order to compute cycle-freeness, we do SCC finding on the phi, and see
// what kind of SCC it ends up in. If it is a singleton, it is cycle-free.
// If it is not in a singleton, it is only cycle free if the other members are
@@ -1436,7 +1446,7 @@ bool NewGVN::isCycleFree(const PHINode *
}
// Evaluate PHI nodes symbolically, and create an expression result.
-const Expression *NewGVN::performSymbolicPHIEvaluation(Instruction *I) {
+const Expression *NewGVN::performSymbolicPHIEvaluation(Instruction *I) const {
// True if one of the incoming phi edges is a backedge.
bool HasBackedge = false;
// All constant tracks the state of whether all the *original* phi operands
@@ -1445,8 +1455,7 @@ const Expression *NewGVN::performSymboli
// not to later change the value of the phi.
// IE it can't be v = phi(undef, v+1)
bool AllConstant = true;
- auto *E =
- cast<PHIExpression>(createPHIExpression(I, HasBackedge, AllConstant));
+ auto *E = cast<PHIExpression>(createPHIExpression(I, HasBackedge, AllConstant));
// We match the semantics of SimplifyPhiNode from InstructionSimplify here.
// See if all arguments are the same.
// We track if any were undef because they need special handling.
@@ -1510,7 +1519,8 @@ const Expression *NewGVN::performSymboli
return E;
}
-const Expression *NewGVN::performSymbolicAggrValueEvaluation(Instruction *I) {
+const Expression *
+NewGVN::performSymbolicAggrValueEvaluation(Instruction *I) const {
if (auto *EI = dyn_cast<ExtractValueInst>(I)) {
auto *II = dyn_cast<IntrinsicInst>(EI->getAggregateOperand());
if (II && EI->getNumIndices() == 1 && *EI->idx_begin() == 0) {
@@ -1548,7 +1558,7 @@ const Expression *NewGVN::performSymboli
return createAggregateValueExpression(I);
}
-const Expression *NewGVN::performSymbolicCmpEvaluation(Instruction *I) {
+const Expression *NewGVN::performSymbolicCmpEvaluation(Instruction *I) const {
auto *CI = dyn_cast<CmpInst>(I);
// See if our operands are equal to those of a previous predicate, and if so,
// if it implies true or false.
@@ -1663,7 +1673,7 @@ const Expression *NewGVN::performSymboli
}
// Substitute and symbolize the value before value numbering.
-const Expression *NewGVN::performSymbolicEvaluation(Value *V) {
+const Expression *NewGVN::performSymbolicEvaluation(Value *V) const {
const Expression *E = nullptr;
if (auto *C = dyn_cast<Constant>(V))
E = createConstantExpression(C);
@@ -1749,7 +1759,7 @@ void NewGVN::markUsersTouched(Value *V)
}
}
-void NewGVN::addMemoryUsers(const MemoryAccess *To, MemoryAccess *U) {
+void NewGVN::addMemoryUsers(const MemoryAccess *To, MemoryAccess *U) const {
DEBUG(dbgs() << "Adding memory user " << *U << " to " << *To << "\n");
MemoryToUsers[To].insert(U);
}
@@ -1772,7 +1782,7 @@ void NewGVN::markMemoryUsersTouched(cons
}
// Add I to the set of users of a given predicate.
-void NewGVN::addPredicateUsers(const PredicateBase *PB, Instruction *I) {
+void NewGVN::addPredicateUsers(const PredicateBase *PB, Instruction *I) const {
if (auto *PBranch = dyn_cast<PredicateBranch>(PB))
PredicateToUsers[PBranch->Condition].insert(I);
else if (auto *PAssume = dyn_cast<PredicateBranch>(PB))
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