SmallVector<BasicBlock*, 32> Worklist;
Worklist.push_back(StartBB);
+ // PredList used inside loop.
+ SmallVector<std::pair<BasicBlock*, PHITransAddr>, 16> PredList;
+
// Keep track of the entries that we know are sorted. Previously cached
// entries will all be sorted. The entries we add we only sort on demand (we
// don't insert every element into its sorted position). We know that we
// the same Pointer.
if (!Pointer.NeedsPHITranslationFromBlock(BB)) {
SkipFirstBlock = false;
+ SmallVector<BasicBlock*, 16> NewBlocks;
for (BasicBlock **PI = PredCache->GetPreds(BB); *PI; ++PI) {
// Verify that we haven't looked at this block yet.
std::pair<DenseMap<BasicBlock*,Value*>::iterator, bool>
InsertRes = Visited.insert(std::make_pair(*PI, Pointer.getAddr()));
if (InsertRes.second) {
// First time we've looked at *PI.
- Worklist.push_back(*PI);
+ NewBlocks.push_back(*PI);
continue;
}
// If we have seen this block before, but it was with a different
// pointer then we have a phi translation failure and we have to treat
// this as a clobber.
- if (InsertRes.first->second != Pointer.getAddr())
+ if (InsertRes.first->second != Pointer.getAddr()) {
+ // Make sure to clean up the Visited map before continuing on to
+ // PredTranslationFailure.
+ for (unsigned i = 0; i < NewBlocks.size(); i++)
+ Visited.erase(NewBlocks[i]);
goto PredTranslationFailure;
+ }
}
+ Worklist.append(NewBlocks.begin(), NewBlocks.end());
continue;
}
NumSortedEntries = Cache->size();
}
Cache = 0;
-
+
+ PredList.clear();
for (BasicBlock **PI = PredCache->GetPreds(BB); *PI; ++PI) {
BasicBlock *Pred = *PI;
-
+ PredList.push_back(std::make_pair(Pred, Pointer));
+
// Get the PHI translated pointer in this predecessor. This can fail if
// not translatable, in which case the getAddr() returns null.
- PHITransAddr PredPointer(Pointer);
+ PHITransAddr &PredPointer = PredList.back().second;
PredPointer.PHITranslateValue(BB, Pred, 0);
Value *PredPtrVal = PredPointer.getAddr();
InsertRes = Visited.insert(std::make_pair(Pred, PredPtrVal));
if (!InsertRes.second) {
+ // We found the pred; take it off the list of preds to visit.
+ PredList.pop_back();
+
// If the predecessor was visited with PredPtr, then we already did
// the analysis and can ignore it.
if (InsertRes.first->second == PredPtrVal)
// Otherwise, the block was previously analyzed with a different
// pointer. We can't represent the result of this case, so we just
// treat this as a phi translation failure.
+
+ // Make sure to clean up the Visited map before continuing on to
+ // PredTranslationFailure.
+ for (unsigned i = 0; i < PredList.size(); i++)
+ Visited.erase(PredList[i].first);
+
goto PredTranslationFailure;
}
-
+ }
+
+ // Actually process results here; this need to be a separate loop to avoid
+ // calling getNonLocalPointerDepFromBB for blocks we don't want to return
+ // any results for. (getNonLocalPointerDepFromBB will modify our
+ // datastructures in ways the code after the PredTranslationFailure label
+ // doesn't expect.)
+ for (unsigned i = 0; i < PredList.size(); i++) {
+ BasicBlock *Pred = PredList[i].first;
+ PHITransAddr &PredPointer = PredList[i].second;
+ Value *PredPtrVal = PredPointer.getAddr();
+
+ bool CanTranslate = true;
// If PHI translation was unable to find an available pointer in this
// predecessor, then we have to assume that the pointer is clobbered in
// that predecessor. We can still do PRE of the load, which would insert
// a computation of the pointer in this predecessor.
- if (PredPtrVal == 0) {
+ if (PredPtrVal == 0)
+ CanTranslate = false;
+
+ // FIXME: it is entirely possible that PHI translating will end up with
+ // the same value. Consider PHI translating something like:
+ // X = phi [x, bb1], [y, bb2]. PHI translating for bb1 doesn't *need*
+ // to recurse here, pedantically speaking.
+
+ // If getNonLocalPointerDepFromBB fails here, that means the cached
+ // result conflicted with the Visited list; we have to conservatively
+ // assume a clobber, but this also does not block PRE of the load.
+ if (!CanTranslate ||
+ getNonLocalPointerDepFromBB(PredPointer,
+ Loc.getWithNewPtr(PredPtrVal),
+ isLoad, Pred,
+ Result, Visited)) {
// Add the entry to the Result list.
NonLocalDepResult Entry(Pred,
MemDepResult::getClobber(Pred->getTerminator()),
NLPI.Pair = BBSkipFirstBlockPair();
continue;
}
-
- // FIXME: it is entirely possible that PHI translating will end up with
- // the same value. Consider PHI translating something like:
- // X = phi [x, bb1], [y, bb2]. PHI translating for bb1 doesn't *need*
- // to recurse here, pedantically speaking.
-
- // If we have a problem phi translating, fall through to the code below
- // to handle the failure condition.
- if (getNonLocalPointerDepFromBB(PredPointer,
- Loc.getWithNewPtr(PredPointer.getAddr()),
- isLoad, Pred,
- Result, Visited))
- goto PredTranslationFailure;
}
// Refresh the CacheInfo/Cache pointer so that it isn't invalidated.
continue;
PredTranslationFailure:
+ // The following code is "failure"; we can't produce a sane translation
+ // for the given block. It assumes that we haven't modified any of
+ // our datastructures while processing the current block.
if (Cache == 0) {
// Refresh the CacheInfo/Cache pointer if it got invalidated.
projects / oota-llvm.git / commitdiff