summaryrefslogtreecommitdiffstats
path: root/llvm/lib/Transforms/Scalar/SCCP.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'llvm/lib/Transforms/Scalar/SCCP.cpp')
-rw-r--r--llvm/lib/Transforms/Scalar/SCCP.cpp190
1 files changed, 80 insertions, 110 deletions
diff --git a/llvm/lib/Transforms/Scalar/SCCP.cpp b/llvm/lib/Transforms/Scalar/SCCP.cpp
index cac8991c5c2..e691cb60a8d 100644
--- a/llvm/lib/Transforms/Scalar/SCCP.cpp
+++ b/llvm/lib/Transforms/Scalar/SCCP.cpp
@@ -69,8 +69,6 @@ STATISTIC(NumDeadBlocks , "Number of basic blocks unreachable");
STATISTIC(IPNumInstRemoved, "Number of instructions removed by IPSCCP");
STATISTIC(IPNumArgsElimed ,"Number of arguments constant propagated by IPSCCP");
STATISTIC(IPNumGlobalConst, "Number of globals found to be constant by IPSCCP");
-STATISTIC(IPNumRangeInfoUsed, "Number of times constant range info was used by"
- "IPSCCP");
namespace {
@@ -343,20 +341,13 @@ public:
return StructValues;
}
- ValueLatticeElement getLatticeValueFor(Value *V) {
+ const LatticeVal &getLatticeValueFor(Value *V) const {
assert(!V->getType()->isStructTy() &&
"Should use getStructLatticeValueFor");
- std::pair<DenseMap<Value*, ValueLatticeElement>::iterator, bool>
- PI = ParamState.insert(std::make_pair(V, ValueLatticeElement()));
- ValueLatticeElement &LV = PI.first->second;
- if (PI.second) {
- DenseMap<Value*, LatticeVal>::const_iterator I = ValueState.find(V);
- assert(I != ValueState.end() &&
- "V not found in ValueState nor Paramstate map!");
- LV = I->second.toValueLattice();
- }
-
- return LV;
+ DenseMap<Value *, LatticeVal>::const_iterator I = ValueState.find(V);
+ assert(I != ValueState.end() &&
+ "V not found in ValueState nor Paramstate map!");
+ return I->second;
}
/// getTrackedRetVals - Get the inferred return value map.
@@ -417,15 +408,16 @@ private:
// markConstant - Make a value be marked as "constant". If the value
// is not already a constant, add it to the instruction work list so that
// the users of the instruction are updated later.
- void markConstant(LatticeVal &IV, Value *V, Constant *C) {
- if (!IV.markConstant(C)) return;
+ bool markConstant(LatticeVal &IV, Value *V, Constant *C) {
+ if (!IV.markConstant(C)) return false;
LLVM_DEBUG(dbgs() << "markConstant: " << *C << ": " << *V << '\n');
pushToWorkList(IV, V);
+ return true;
}
- void markConstant(Value *V, Constant *C) {
+ bool markConstant(Value *V, Constant *C) {
assert(!V->getType()->isStructTy() && "structs should use mergeInValue");
- markConstant(ValueState[V], V, C);
+ return markConstant(ValueState[V], V, C);
}
void markForcedConstant(Value *V, Constant *C) {
@@ -439,8 +431,8 @@ private:
// markOverdefined - Make a value be marked as "overdefined". If the
// value is not already overdefined, add it to the overdefined instruction
// work list so that the users of the instruction are updated later.
- void markOverdefined(LatticeVal &IV, Value *V) {
- if (!IV.markOverdefined()) return;
+ bool markOverdefined(LatticeVal &IV, Value *V) {
+ if (!IV.markOverdefined()) return false;
LLVM_DEBUG(dbgs() << "markOverdefined: ";
if (auto *F = dyn_cast<Function>(V)) dbgs()
@@ -448,23 +440,25 @@ private:
else dbgs() << *V << '\n');
// Only instructions go on the work list
pushToWorkList(IV, V);
+ return true;
}
- void mergeInValue(LatticeVal &IV, Value *V, LatticeVal MergeWithV) {
+ bool mergeInValue(LatticeVal &IV, Value *V, LatticeVal MergeWithV) {
if (IV.isOverdefined() || MergeWithV.isUnknown())
- return; // Noop.
+ return false; // Noop.
if (MergeWithV.isOverdefined())
return markOverdefined(IV, V);
if (IV.isUnknown())
return markConstant(IV, V, MergeWithV.getConstant());
if (IV.getConstant() != MergeWithV.getConstant())
return markOverdefined(IV, V);
+ return false;
}
- void mergeInValue(Value *V, LatticeVal MergeWithV) {
+ bool mergeInValue(Value *V, LatticeVal MergeWithV) {
assert(!V->getType()->isStructTy() &&
"non-structs should use markConstant");
- mergeInValue(ValueState[V], V, MergeWithV);
+ return mergeInValue(ValueState[V], V, MergeWithV);
}
/// getValueState - Return the LatticeVal object that corresponds to the
@@ -733,7 +727,7 @@ void SCCPSolver::visitPHINode(PHINode &PN) {
// If this PN returns a struct, just mark the result overdefined.
// TODO: We could do a lot better than this if code actually uses this.
if (PN.getType()->isStructTy())
- return markOverdefined(&PN);
+ return (void)markOverdefined(&PN);
if (getValueState(&PN).isOverdefined())
return; // Quick exit
@@ -741,7 +735,7 @@ void SCCPSolver::visitPHINode(PHINode &PN) {
// Super-extra-high-degree PHI nodes are unlikely to ever be marked constant,
// and slow us down a lot. Just mark them overdefined.
if (PN.getNumIncomingValues() > 64)
- return markOverdefined(&PN);
+ return (void)markOverdefined(&PN);
// Look at all of the executable operands of the PHI node. If any of them
// are overdefined, the PHI becomes overdefined as well. If they are all
@@ -757,7 +751,7 @@ void SCCPSolver::visitPHINode(PHINode &PN) {
continue;
if (IV.isOverdefined()) // PHI node becomes overdefined!
- return markOverdefined(&PN);
+ return (void)markOverdefined(&PN);
if (!OperandVal) { // Grab the first value.
OperandVal = IV.getConstant();
@@ -771,7 +765,7 @@ void SCCPSolver::visitPHINode(PHINode &PN) {
// Check to see if there are two different constants merging, if so, the PHI
// node is overdefined.
if (IV.getConstant() != OperandVal)
- return markOverdefined(&PN);
+ return (void)markOverdefined(&PN);
}
// If we exited the loop, this means that the PHI node only has constant
@@ -839,11 +833,11 @@ void SCCPSolver::visitExtractValueInst(ExtractValueInst &EVI) {
// If this returns a struct, mark all elements over defined, we don't track
// structs in structs.
if (EVI.getType()->isStructTy())
- return markOverdefined(&EVI);
+ return (void)markOverdefined(&EVI);
// If this is extracting from more than one level of struct, we don't know.
if (EVI.getNumIndices() != 1)
- return markOverdefined(&EVI);
+ return (void)markOverdefined(&EVI);
Value *AggVal = EVI.getAggregateOperand();
if (AggVal->getType()->isStructTy()) {
@@ -852,19 +846,19 @@ void SCCPSolver::visitExtractValueInst(ExtractValueInst &EVI) {
mergeInValue(getValueState(&EVI), &EVI, EltVal);
} else {
// Otherwise, must be extracting from an array.
- return markOverdefined(&EVI);
+ return (void)markOverdefined(&EVI);
}
}
void SCCPSolver::visitInsertValueInst(InsertValueInst &IVI) {
auto *STy = dyn_cast<StructType>(IVI.getType());
if (!STy)
- return markOverdefined(&IVI);
+ return (void)markOverdefined(&IVI);
// If this has more than one index, we can't handle it, drive all results to
// undef.
if (IVI.getNumIndices() != 1)
- return markOverdefined(&IVI);
+ return (void)markOverdefined(&IVI);
Value *Aggr = IVI.getAggregateOperand();
unsigned Idx = *IVI.idx_begin();
@@ -893,7 +887,7 @@ void SCCPSolver::visitSelectInst(SelectInst &I) {
// If this select returns a struct, just mark the result overdefined.
// TODO: We could do a lot better than this if code actually uses this.
if (I.getType()->isStructTy())
- return markOverdefined(&I);
+ return (void)markOverdefined(&I);
LatticeVal CondValue = getValueState(I.getCondition());
if (CondValue.isUnknown())
@@ -914,12 +908,12 @@ void SCCPSolver::visitSelectInst(SelectInst &I) {
// select ?, C, C -> C.
if (TVal.isConstant() && FVal.isConstant() &&
TVal.getConstant() == FVal.getConstant())
- return markConstant(&I, FVal.getConstant());
+ return (void)markConstant(&I, FVal.getConstant());
if (TVal.isUnknown()) // select ?, undef, X -> X.
- return mergeInValue(&I, FVal);
+ return (void)mergeInValue(&I, FVal);
if (FVal.isUnknown()) // select ?, X, undef -> X.
- return mergeInValue(&I, TVal);
+ return (void)mergeInValue(&I, TVal);
markOverdefined(&I);
}
@@ -937,7 +931,7 @@ void SCCPSolver::visitBinaryOperator(Instruction &I) {
// X op Y -> undef.
if (isa<UndefValue>(C))
return;
- return markConstant(IV, &I, C);
+ return (void)markConstant(IV, &I, C);
}
// If something is undef, wait for it to resolve.
@@ -950,7 +944,7 @@ void SCCPSolver::visitBinaryOperator(Instruction &I) {
// overdefined, and we can replace it with zero.
if (I.getOpcode() == Instruction::UDiv || I.getOpcode() == Instruction::SDiv)
if (V1State.isConstant() && V1State.getConstant()->isNullValue())
- return markConstant(IV, &I, V1State.getConstant());
+ return (void)markConstant(IV, &I, V1State.getConstant());
// If this is:
// -> AND/MUL with 0
@@ -973,12 +967,12 @@ void SCCPSolver::visitBinaryOperator(Instruction &I) {
// X and 0 = 0
// X * 0 = 0
if (NonOverdefVal->getConstant()->isNullValue())
- return markConstant(IV, &I, NonOverdefVal->getConstant());
+ return (void)markConstant(IV, &I, NonOverdefVal->getConstant());
} else {
// X or -1 = -1
if (ConstantInt *CI = NonOverdefVal->getConstantInt())
if (CI->isMinusOne())
- return markConstant(IV, &I, NonOverdefVal->getConstant());
+ return (void)markConstant(IV, &I, NonOverdefVal->getConstant());
}
}
}
@@ -988,18 +982,32 @@ void SCCPSolver::visitBinaryOperator(Instruction &I) {
// Handle ICmpInst instruction.
void SCCPSolver::visitCmpInst(CmpInst &I) {
- LatticeVal V1State = getValueState(I.getOperand(0));
- LatticeVal V2State = getValueState(I.getOperand(1));
-
LatticeVal &IV = ValueState[&I];
if (IV.isOverdefined()) return;
- if (V1State.isConstant() && V2State.isConstant()) {
- Constant *C = ConstantExpr::getCompare(
- I.getPredicate(), V1State.getConstant(), V2State.getConstant());
+ Value *Op1 = I.getOperand(0);
+ Value *Op2 = I.getOperand(1);
+
+ // For parameters, use ParamState which includes constant range info if
+ // available.
+ auto V1Param = ParamState.find(Op1);
+ ValueLatticeElement V1State = (V1Param != ParamState.end())
+ ? V1Param->second
+ : getValueState(Op1).toValueLattice();
+
+ auto V2Param = ParamState.find(Op2);
+ ValueLatticeElement V2State = V2Param != ParamState.end()
+ ? V2Param->second
+ : getValueState(Op2).toValueLattice();
+
+ Constant *C = V1State.getCompare(I.getPredicate(), I.getType(), V2State);
+ if (C) {
if (isa<UndefValue>(C))
return;
- return markConstant(IV, &I, C);
+ LatticeVal CV;
+ CV.markConstant(C);
+ mergeInValue(&I, CV);
+ return;
}
// If operands are still unknown, wait for it to resolve.
@@ -1023,7 +1031,7 @@ void SCCPSolver::visitGetElementPtrInst(GetElementPtrInst &I) {
return; // Operands are not resolved yet.
if (State.isOverdefined())
- return markOverdefined(&I);
+ return (void)markOverdefined(&I);
assert(State.isConstant() && "Unknown state!");
Operands.push_back(State.getConstant());
@@ -1061,7 +1069,7 @@ void SCCPSolver::visitStoreInst(StoreInst &SI) {
void SCCPSolver::visitLoadInst(LoadInst &I) {
// If this load is of a struct, just mark the result overdefined.
if (I.getType()->isStructTy())
- return markOverdefined(&I);
+ return (void)markOverdefined(&I);
LatticeVal PtrVal = getValueState(I.getOperand(0));
if (PtrVal.isUnknown()) return; // The pointer is not resolved yet!
@@ -1070,7 +1078,7 @@ void SCCPSolver::visitLoadInst(LoadInst &I) {
if (IV.isOverdefined()) return;
if (!PtrVal.isConstant() || I.isVolatile())
- return markOverdefined(IV, &I);
+ return (void)markOverdefined(IV, &I);
Constant *Ptr = PtrVal.getConstant();
@@ -1099,7 +1107,7 @@ void SCCPSolver::visitLoadInst(LoadInst &I) {
if (Constant *C = ConstantFoldLoadFromConstPtr(Ptr, I.getType(), DL)) {
if (isa<UndefValue>(C))
return;
- return markConstant(IV, &I, C);
+ return (void)markConstant(IV, &I, C);
}
// Otherwise we cannot say for certain what value this load will produce.
@@ -1131,7 +1139,7 @@ CallOverdefined:
if (State.isUnknown())
return; // Operands are not resolved yet.
if (State.isOverdefined())
- return markOverdefined(I);
+ return (void)markOverdefined(I);
assert(State.isConstant() && "Unknown state!");
Operands.push_back(State.getConstant());
}
@@ -1145,12 +1153,12 @@ CallOverdefined:
// call -> undef.
if (isa<UndefValue>(C))
return;
- return markConstant(I, C);
+ return (void)markConstant(I, C);
}
}
// Otherwise, we don't know anything about this call, mark it overdefined.
- return markOverdefined(I);
+ return (void)markOverdefined(I);
}
// If this is a local function that doesn't have its address taken, mark its
@@ -1178,8 +1186,16 @@ CallOverdefined:
} else {
// Most other parts of the Solver still only use the simpler value
// lattice, so we propagate changes for parameters to both lattices.
- getParamState(&*AI).mergeIn(getValueState(*CAI).toValueLattice(), DL);
- mergeInValue(&*AI, getValueState(*CAI));
+ LatticeVal ConcreteArgument = getValueState(*CAI);
+ bool ParamChanged =
+ getParamState(&*AI).mergeIn(ConcreteArgument.toValueLattice(), DL);
+ bool ValueChanged = mergeInValue(&*AI, ConcreteArgument);
+ // Add argument to work list, if the state of a parameter changes but
+ // ValueState does not change (because it is already overdefined there),
+ // We have to take changes in ParamState into account, as it is used
+ // when evaluating Cmp instructions.
+ if (!ValueChanged && ParamChanged)
+ pushToWorkList(ValueState[&*AI], &*AI);
}
}
}
@@ -1472,7 +1488,11 @@ bool SCCPSolver::ResolvedUndefsIn(Function &F) {
break;
case Instruction::ICmp:
// X == undef -> undef. Other comparisons get more complicated.
- if (cast<ICmpInst>(&I)->isEquality())
+ Op0LV = getValueState(I.getOperand(0));
+ Op1LV = getValueState(I.getOperand(1));
+
+ if ((Op0LV.isUnknown() || Op1LV.isUnknown()) &&
+ cast<ICmpInst>(&I)->isEquality())
break;
markOverdefined(&I);
return true;
@@ -1583,45 +1603,6 @@ bool SCCPSolver::ResolvedUndefsIn(Function &F) {
return false;
}
-static bool tryToReplaceWithConstantRange(SCCPSolver &Solver, Value *V) {
- bool Changed = false;
-
- // Currently we only use range information for integer values.
- if (!V->getType()->isIntegerTy())
- return false;
-
- const ValueLatticeElement &IV = Solver.getLatticeValueFor(V);
- if (!IV.isConstantRange())
- return false;
-
- for (auto UI = V->uses().begin(), E = V->uses().end(); UI != E;) {
- const Use &U = *UI++;
- auto *Icmp = dyn_cast<ICmpInst>(U.getUser());
- if (!Icmp || !Solver.isBlockExecutable(Icmp->getParent()))
- continue;
-
- auto getIcmpLatticeValue = [&](Value *Op) {
- if (auto *C = dyn_cast<Constant>(Op))
- return ValueLatticeElement::get(C);
- return Solver.getLatticeValueFor(Op);
- };
-
- ValueLatticeElement A = getIcmpLatticeValue(Icmp->getOperand(0));
- ValueLatticeElement B = getIcmpLatticeValue(Icmp->getOperand(1));
-
- Constant *C = A.getCompare(Icmp->getPredicate(), Icmp->getType(), B);
- if (C) {
- Icmp->replaceAllUsesWith(C);
- LLVM_DEBUG(dbgs() << "Replacing " << *Icmp << " with " << *C
- << ", because of range information " << A << " " << B
- << "\n");
- Icmp->eraseFromParent();
- Changed = true;
- }
- }
- return Changed;
-}
-
static bool tryToReplaceWithConstant(SCCPSolver &Solver, Value *V) {
Constant *Const = nullptr;
if (V->getType()->isStructTy()) {
@@ -1639,19 +1620,11 @@ static bool tryToReplaceWithConstant(SCCPSolver &Solver, Value *V) {
}
Const = ConstantStruct::get(ST, ConstVals);
} else {
- const ValueLatticeElement &IV = Solver.getLatticeValueFor(V);
+ const LatticeVal &IV = Solver.getLatticeValueFor(V);
if (IV.isOverdefined())
return false;
- if (IV.isConstantRange()) {
- if (IV.getConstantRange().isSingleElement())
- Const =
- ConstantInt::get(V->getType(), IV.asConstantInteger().getValue());
- else
- return false;
- } else
- Const =
- IV.isConstant() ? IV.getConstant() : UndefValue::get(V->getType());
+ Const = IV.isConstant() ? IV.getConstant() : UndefValue::get(V->getType());
}
assert(Const && "Constant is nullptr here!");
@@ -1896,9 +1869,6 @@ bool llvm::runIPSCCP(Module &M, const DataLayout &DL,
++IPNumArgsElimed;
continue;
}
-
- if (!AI->use_empty() && tryToReplaceWithConstantRange(Solver, &*AI))
- ++IPNumRangeInfoUsed;
}
for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
OpenPOWER on IntegriCloud