[llvm-commits] [llvm] r88866 - /llvm/trunk/lib/Analysis/LazyValueInfo.cpp
Chris Lattner
sabre at nondot.org
Sun Nov 15 11:59:49 PST 2009
Author: lattner
Date: Sun Nov 15 13:59:49 2009
New Revision: 88866
URL: http://llvm.org/viewvc/llvm-project?rev=88866&view=rev
Log:
refactor a bunch of code forming the new LazyValueInfoCache
and LVIQuery classes, no functionality change.
Modified:
llvm/trunk/lib/Analysis/LazyValueInfo.cpp
Modified: llvm/trunk/lib/Analysis/LazyValueInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/LazyValueInfo.cpp?rev=88866&r1=88865&r2=88866&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/LazyValueInfo.cpp (original)
+++ llvm/trunk/lib/Analysis/LazyValueInfo.cpp Sun Nov 15 13:59:49 2009
@@ -195,69 +195,75 @@
}
//===----------------------------------------------------------------------===//
-// LazyValueInfo Impl
+// LazyValueInfoCache Decl
//===----------------------------------------------------------------------===//
-bool LazyValueInfo::runOnFunction(Function &F) {
- TD = getAnalysisIfAvailable<TargetData>();
- // Fully lazy.
- return false;
-}
+namespace {
+ /// LazyValueInfoCache - This is the cache kept by LazyValueInfo which
+ /// maintains information about queries across the clients' queries.
+ class LazyValueInfoCache {
+ public:
+ /// BlockCacheEntryTy - This is a computed lattice value at the end of the
+ /// specified basic block for a Value* that depends on context.
+ typedef std::pair<BasicBlock*, LVILatticeVal> BlockCacheEntryTy;
+
+ /// ValueCacheEntryTy - This is all of the cached block information for
+ /// exactly one Value*. The entries are sorted by the BasicBlock* of the
+ /// entries, allowing us to do a lookup with a binary search.
+ typedef std::vector<BlockCacheEntryTy> ValueCacheEntryTy;
+
+ private:
+ /// ValueCache - This is all of the cached information for all values,
+ /// mapped from Value* to key information.
+ DenseMap<Value*, ValueCacheEntryTy> ValueCache;
+ public:
+
+ /// getValueInBlock - This is the query interface to determine the lattice
+ /// value for the specified Value* at the end of the specified block.
+ LVILatticeVal getValueInBlock(Value *V, BasicBlock *BB);
+
+ /// getValueOnEdge - This is the query interface to determine the lattice
+ /// value for the specified Value* that is true on the specified edge.
+ LVILatticeVal getValueOnEdge(Value *V, BasicBlock *FromBB,BasicBlock *ToBB);
+ };
+} // end anonymous namespace
-void LazyValueInfo::releaseMemory() {
- // No caching yet.
-}
+//===----------------------------------------------------------------------===//
+// LVIQuery Impl
+//===----------------------------------------------------------------------===//
-static LVILatticeVal GetValueInBlock(Value *V, BasicBlock *BB,
- DenseMap<BasicBlock*, LVILatticeVal> &);
+namespace {
+ /// LVIQuery - This is a transient object that exists while a query is
+ /// being performed.
+ class LVIQuery {
+ typedef LazyValueInfoCache::BlockCacheEntryTy BlockCacheEntryTy;
+ typedef LazyValueInfoCache::ValueCacheEntryTy ValueCacheEntryTy;
+
+ /// This is the current value being queried.
+ Value *Val;
+
+ /// This is all of the cached information about this value.
+ ValueCacheEntryTy &Cache;
+
+ /// BlockVals Temporary Cache used while processing a query.
+ DenseMap<BasicBlock*, LVILatticeVal> BlockVals;
-static LVILatticeVal GetValueOnEdge(Value *V, BasicBlock *BBFrom,
- BasicBlock *BBTo,
- DenseMap<BasicBlock*, LVILatticeVal> &BlockVals) {
- // FIXME: Pull edge logic out of jump threading.
-
-
- if (BranchInst *BI = dyn_cast<BranchInst>(BBFrom->getTerminator())) {
- // If this is a conditional branch and only one successor goes to BBTo, then
- // we maybe able to infer something from the condition.
- if (BI->isConditional() &&
- BI->getSuccessor(0) != BI->getSuccessor(1)) {
- bool isTrueDest = BI->getSuccessor(0) == BBTo;
- assert(BI->getSuccessor(!isTrueDest) == BBTo &&
- "BBTo isn't a successor of BBFrom");
-
- // If V is the condition of the branch itself, then we know exactly what
- // it is.
- if (BI->getCondition() == V)
- return LVILatticeVal::get(ConstantInt::get(
- Type::getInt1Ty(V->getContext()), isTrueDest));
-
- // If the condition of the branch is an equality comparison, we may be
- // able to infer the value.
- if (ICmpInst *ICI = dyn_cast<ICmpInst>(BI->getCondition()))
- if (ICI->isEquality() && ICI->getOperand(0) == V &&
- isa<Constant>(ICI->getOperand(1))) {
- // We know that V has the RHS constant if this is a true SETEQ or
- // false SETNE.
- if (isTrueDest == (ICI->getPredicate() == ICmpInst::ICMP_EQ))
- return LVILatticeVal::get(cast<Constant>(ICI->getOperand(1)));
- return LVILatticeVal::getNot(cast<Constant>(ICI->getOperand(1)));
- }
+ public:
+
+ LVIQuery(Value *V, ValueCacheEntryTy &VC) : Val(V), Cache(VC) {
}
- }
-
- // TODO: Info from switch.
-
-
- // Otherwise see if the value is known in the block.
- return GetValueInBlock(V, BBFrom, BlockVals);
-}
-static LVILatticeVal GetValueInBlock(Value *V, BasicBlock *BB,
- DenseMap<BasicBlock*, LVILatticeVal> &BlockVals) {
+ LVILatticeVal getBlockValue(BasicBlock *BB);
+
+ LVILatticeVal getEdgeValue(BasicBlock *FromBB, BasicBlock *ToBB);
+ };
+} // end anonymous namespace
+
+
+LVILatticeVal LVIQuery::getBlockValue(BasicBlock *BB) {
// See if we already have a value for this block.
LVILatticeVal &BBLV = BlockVals[BB];
-
+
// If we've already computed this block's value, return it.
if (!BBLV.isUndefined())
return BBLV;
@@ -266,18 +272,17 @@
// lattice value to overdefined, so that cycles will terminate and be
// conservatively correct.
BBLV.markOverdefined();
-
- LVILatticeVal Result; // Start Undefined.
- // If V is live in to BB, see if our predecessors know anything about it.
- Instruction *BBI = dyn_cast<Instruction>(V);
+ // If V is live into BB, see if our predecessors know anything about it.
+ Instruction *BBI = dyn_cast<Instruction>(Val);
if (BBI == 0 || BBI->getParent() != BB) {
+ LVILatticeVal Result; // Start Undefined.
unsigned NumPreds = 0;
// Loop over all of our predecessors, merging what we know from them into
// result.
for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) {
- Result.mergeIn(GetValueOnEdge(V, *PI, BB, BlockVals));
+ Result.mergeIn(getEdgeValue(*PI, BB));
// If we hit overdefined, exit early. The BlockVals entry is already set
// to overdefined.
@@ -289,16 +294,16 @@
// If this is the entry block, we must be asking about an argument. The
// value is overdefined.
if (NumPreds == 0 && BB == &BB->getParent()->front()) {
- assert(isa<Argument>(V) && "Unknown live-in to the entry block");
+ assert(isa<Argument>(Val) && "Unknown live-in to the entry block");
Result.markOverdefined();
return Result;
}
-
+
// Return the merged value, which is more precise than 'overdefined'.
assert(!Result.isOverdefined());
return BlockVals[BB] = Result;
}
-
+
// If this value is defined by an instruction in this block, we have to
// process it here somehow or return overdefined.
if (PHINode *PN = dyn_cast<PHINode>(BBI)) {
@@ -308,24 +313,115 @@
}
+ LVILatticeVal Result;
Result.markOverdefined();
return BlockVals[BB] = Result;
}
-Constant *LazyValueInfo::getConstant(Value *V, BasicBlock *BB) {
- // If already a constant, return it.
- if (Constant *VC = dyn_cast<Constant>(V))
- return VC;
+/// getEdgeValue - This method
+LVILatticeVal LVIQuery::getEdgeValue(BasicBlock *BBFrom, BasicBlock *BBTo) {
+ if (BranchInst *BI = dyn_cast<BranchInst>(BBFrom->getTerminator())) {
+ // If this is a conditional branch and only one successor goes to BBTo, then
+ // we maybe able to infer something from the condition.
+ if (BI->isConditional() &&
+ BI->getSuccessor(0) != BI->getSuccessor(1)) {
+ bool isTrueDest = BI->getSuccessor(0) == BBTo;
+ assert(BI->getSuccessor(!isTrueDest) == BBTo &&
+ "BBTo isn't a successor of BBFrom");
+
+ // If V is the condition of the branch itself, then we know exactly what
+ // it is.
+ if (BI->getCondition() == Val)
+ return LVILatticeVal::get(ConstantInt::get(
+ Type::getInt1Ty(Val->getContext()), isTrueDest));
+
+ // If the condition of the branch is an equality comparison, we may be
+ // able to infer the value.
+ if (ICmpInst *ICI = dyn_cast<ICmpInst>(BI->getCondition()))
+ if (ICI->isEquality() && ICI->getOperand(0) == Val &&
+ isa<Constant>(ICI->getOperand(1))) {
+ // We know that V has the RHS constant if this is a true SETEQ or
+ // false SETNE.
+ if (isTrueDest == (ICI->getPredicate() == ICmpInst::ICMP_EQ))
+ return LVILatticeVal::get(cast<Constant>(ICI->getOperand(1)));
+ return LVILatticeVal::getNot(cast<Constant>(ICI->getOperand(1)));
+ }
+ }
+ }
- DenseMap<BasicBlock*, LVILatticeVal> BlockValues;
+ // TODO: Info from switch.
+
+ // TODO: Handle more complex conditionals. If (v == 0 || v2 < 1) is false, we
+ // know that v != 0.
+
+ // Otherwise see if the value is known in the block.
+ return getBlockValue(BBFrom);
+}
+
+
+//===----------------------------------------------------------------------===//
+// LazyValueInfoCache Impl
+//===----------------------------------------------------------------------===//
+
+LVILatticeVal LazyValueInfoCache::getValueInBlock(Value *V, BasicBlock *BB) {
+ // If already a constant, there is nothing to compute.
+ if (Constant *VC = dyn_cast<Constant>(V))
+ return LVILatticeVal::get(VC);
DEBUG(errs() << "Getting value " << *V << " at end of block '"
- << BB->getName() << "'\n");
- LVILatticeVal Result = GetValueInBlock(V, BB, BlockValues);
+ << BB->getName() << "'\n");
+
+ LVILatticeVal Result = LVIQuery(V, ValueCache[V]).getBlockValue(BB);
DEBUG(errs() << " Result = " << Result << "\n");
+ return Result;
+}
+LVILatticeVal LazyValueInfoCache::
+getValueOnEdge(Value *V, BasicBlock *FromBB, BasicBlock *ToBB) {
+ // If already a constant, there is nothing to compute.
+ if (Constant *VC = dyn_cast<Constant>(V))
+ return LVILatticeVal::get(VC);
+
+ DEBUG(errs() << "Getting value " << *V << " on edge from '"
+ << FromBB->getName() << "' to '" << ToBB->getName() << "'\n");
+ LVILatticeVal Result =
+ LVIQuery(V, ValueCache[V]).getEdgeValue(FromBB, ToBB);
+
+ DEBUG(errs() << " Result = " << Result << "\n");
+
+ return Result;
+}
+
+//===----------------------------------------------------------------------===//
+// LazyValueInfo Impl
+//===----------------------------------------------------------------------===//
+
+bool LazyValueInfo::runOnFunction(Function &F) {
+ TD = getAnalysisIfAvailable<TargetData>();
+ // Fully lazy.
+ return false;
+}
+
+/// getCache - This lazily constructs the LazyValueInfoCache.
+static LazyValueInfoCache &getCache(void *&PImpl) {
+ if (!PImpl)
+ PImpl = new LazyValueInfoCache();
+ return *static_cast<LazyValueInfoCache*>(PImpl);
+}
+
+void LazyValueInfo::releaseMemory() {
+ // If the cache was allocated, free it.
+ if (PImpl) {
+ delete &getCache(PImpl);
+ PImpl = 0;
+ }
+}
+
+Constant *LazyValueInfo::getConstant(Value *V, BasicBlock *BB) {
+ LVILatticeVal Result = getCache(PImpl).getValueInBlock(V, BB);
+
if (Result.isConstant())
return Result.getConstant();
return 0;
@@ -335,17 +431,7 @@
/// constant on the specified edge. Return null if not.
Constant *LazyValueInfo::getConstantOnEdge(Value *V, BasicBlock *FromBB,
BasicBlock *ToBB) {
- // If already a constant, return it.
- if (Constant *VC = dyn_cast<Constant>(V))
- return VC;
-
- DenseMap<BasicBlock*, LVILatticeVal> BlockValues;
-
- DEBUG(errs() << "Getting value " << *V << " on edge from '"
- << FromBB->getName() << "' to '" << ToBB->getName() << "'\n");
- LVILatticeVal Result = GetValueOnEdge(V, FromBB, ToBB, BlockValues);
-
- DEBUG(errs() << " Result = " << Result << "\n");
+ LVILatticeVal Result = getCache(PImpl).getValueOnEdge(V, FromBB, ToBB);
if (Result.isConstant())
return Result.getConstant();
@@ -358,19 +444,7 @@
LazyValueInfo::Tristate
LazyValueInfo::getPredicateOnEdge(unsigned Pred, Value *V, Constant *C,
BasicBlock *FromBB, BasicBlock *ToBB) {
- LVILatticeVal Result;
-
- // If already a constant, we can use constant folding.
- if (Constant *VC = dyn_cast<Constant>(V)) {
- Result = LVILatticeVal::get(VC);
- } else {
- DenseMap<BasicBlock*, LVILatticeVal> BlockValues;
-
- DEBUG(errs() << "Getting value " << *V << " on edge from '"
- << FromBB->getName() << "' to '" << ToBB->getName() << "'\n");
- Result = GetValueOnEdge(V, FromBB, ToBB, BlockValues);
- DEBUG(errs() << " Result = " << Result << "\n");
- }
+ LVILatticeVal Result = getCache(PImpl).getValueOnEdge(V, FromBB, ToBB);
// If we know the value is a constant, evaluate the conditional.
Constant *Res = 0;
@@ -378,7 +452,10 @@
Res = ConstantFoldCompareInstOperands(Pred, Result.getConstant(), C, TD);
if (ConstantInt *ResCI = dyn_cast_or_null<ConstantInt>(Res))
return ResCI->isZero() ? False : True;
- } else if (Result.isNotConstant()) {
+ return Unknown;
+ }
+
+ if (Result.isNotConstant()) {
// If this is an equality comparison, we can try to fold it knowing that
// "V != C1".
if (Pred == ICmpInst::ICMP_EQ) {
@@ -394,6 +471,7 @@
if (Res->isNullValue())
return True;
}
+ return Unknown;
}
return Unknown;
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