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Add a bool to isEdgeFeasible that tells it whether to treat unknown

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value as undef or untracked.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51295 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2008-05-20 03:39:39 +00:00
parent 638e378f2c
commit 28a8dbc35f
2 changed files with 27 additions and 10 deletions
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11
include/llvm/Analysis/SparsePropagation.h
View File

@ -147,8 +147,12 @@ public:
LatticeVal getOrInitValueState(Value *V);
/// isEdgeFeasible - Return true if the control flow edge from the 'From'
/// basic block to the 'To' basic block is currently feasible...
bool isEdgeFeasible(BasicBlock *From, BasicBlock *To);
/// basic block to the 'To' basic block is currently feasible. If
/// AggressiveUndef is true, then this treats values with unknown lattice
/// values as undefined. This is generally only useful when solving the
/// lattice, not when querying it.
bool isEdgeFeasible(BasicBlock *From, BasicBlock *To,
bool AggressiveUndef = false);
private:
/// UpdateState - When the state for some instruction is potentially updated,
@ -165,7 +169,8 @@ private:
/// getFeasibleSuccessors - Return a vector of booleans to indicate which
/// successors are reachable from a given terminator instruction.
void getFeasibleSuccessors(TerminatorInst &TI, SmallVectorImpl<bool> &Succs);
void getFeasibleSuccessors(TerminatorInst &TI, SmallVectorImpl<bool> &Succs,
bool AggressiveUndef);
void visitInst(Instruction &I);
void visitPHINode(PHINode &I);

26
lib/Analysis/SparsePropagation.cpp
View File

@ -115,7 +115,8 @@ void SparseSolver::markEdgeExecutable(BasicBlock *Source, BasicBlock *Dest) {
/// getFeasibleSuccessors - Return a vector of booleans to indicate which
/// successors are reachable from a given terminator instruction.
void SparseSolver::getFeasibleSuccessors(TerminatorInst &TI,
SmallVectorImpl<bool> &Succs) {
SmallVectorImpl<bool> &Succs,
bool AggressiveUndef) {
Succs.resize(TI.getNumSuccessors());
if (TI.getNumSuccessors() == 0) return;
@ -125,7 +126,12 @@ void SparseSolver::getFeasibleSuccessors(TerminatorInst &TI,
return;
}
LatticeVal BCValue = getOrInitValueState(BI->getCondition());
LatticeVal BCValue;
if (AggressiveUndef)
BCValue = getOrInitValueState(BI->getCondition());
else
BCValue = getLatticeState(BI->getCondition());
if (BCValue == LatticeFunc->getOverdefinedVal() ||
BCValue == LatticeFunc->getUntrackedVal()) {
// Overdefined condition variables can branch either way.
@ -157,7 +163,12 @@ void SparseSolver::getFeasibleSuccessors(TerminatorInst &TI,
}
SwitchInst &SI = cast<SwitchInst>(TI);
LatticeVal SCValue = getOrInitValueState(SI.getCondition());
LatticeVal SCValue;
if (AggressiveUndef)
SCValue = getOrInitValueState(SI.getCondition());
else
SCValue = getLatticeState(SI.getCondition());
if (SCValue == LatticeFunc->getOverdefinedVal() ||
SCValue == LatticeFunc->getUntrackedVal()) {
// All destinations are executable!
@ -182,10 +193,11 @@ void SparseSolver::getFeasibleSuccessors(TerminatorInst &TI,
/// isEdgeFeasible - Return true if the control flow edge from the 'From'
/// basic block to the 'To' basic block is currently feasible...
bool SparseSolver::isEdgeFeasible(BasicBlock *From, BasicBlock *To) {
bool SparseSolver::isEdgeFeasible(BasicBlock *From, BasicBlock *To,
bool AggressiveUndef) {
SmallVector<bool, 16> SuccFeasible;
TerminatorInst *TI = From->getTerminator();
getFeasibleSuccessors(*TI, SuccFeasible);
getFeasibleSuccessors(*TI, SuccFeasible, AggressiveUndef);
for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
if (TI->getSuccessor(i) == To && SuccFeasible[i])
@ -196,7 +208,7 @@ bool SparseSolver::isEdgeFeasible(BasicBlock *From, BasicBlock *To) {
void SparseSolver::visitTerminatorInst(TerminatorInst &TI) {
SmallVector<bool, 16> SuccFeasible;
getFeasibleSuccessors(TI, SuccFeasible);
getFeasibleSuccessors(TI, SuccFeasible, true);
BasicBlock *BB = TI.getParent();
@ -226,7 +238,7 @@ void SparseSolver::visitPHINode(PHINode &PN) {
// transfer function to give us the merge of the incoming values.
for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
// If the edge is not yet known to be feasible, it doesn't impact the PHI.
if (!isEdgeFeasible(PN.getIncomingBlock(i), PN.getParent()))
if (!isEdgeFeasible(PN.getIncomingBlock(i), PN.getParent(), true))
continue;
// Merge in this value.