- PtrAccessSet &S = UseDeferred ? DeferredAccesses : Accesses;
- for (PtrAccessSet::iterator AI = S.begin(), AE = S.end(); AI != AE; ++AI) {
- const MemAccessInfo &Access = *AI;
- Value *Ptr = Access.getPointer();
- bool IsWrite = Access.getInt();
-
- DepCands.insert(Access);
-
- // Memorize read-only pointers for later processing and skip them in the
- // first round (they need to be checked after we have seen all write
- // pointers). Note: we also mark pointer that are not consecutive as
- // "read-only" pointers (so that we check "a[b[i]] +="). Hence, we need the
- // second check for "!IsWrite".
- bool IsReadOnlyPtr = ReadOnlyPtr.count(Ptr) && !IsWrite;
- if (!UseDeferred && IsReadOnlyPtr) {
- DeferredAccesses.insert(Access);
- continue;
- }
+ DEBUG(dbgs() << "LV: Processing memory accesses...\n");
+ DEBUG(dbgs() << " AST: "; AST.dump());
+ DEBUG(dbgs() << "LV: Accesses:\n");
+ DEBUG({
+ for (auto A : Accesses)
+ dbgs() << "\t" << *A.getPointer() << " (" <<
+ (A.getInt() ? "write" : (ReadOnlyPtr.count(A.getPointer()) ?
+ "read-only" : "read")) << ")\n";
+ });
+
+ // The AliasSetTracker has nicely partitioned our pointers by metadata
+ // compatibility and potential for underlying-object overlap. As a result, we
+ // only need to check for potential pointer dependencies within each alias
+ // set.
+ for (auto &AS : AST) {
+ // Note that both the alias-set tracker and the alias sets themselves used
+ // linked lists internally and so the iteration order here is deterministic
+ // (matching the original instruction order within each set).
+
+ bool SetHasWrite = false;
+
+ // Map of pointers to last access encountered.
+ typedef DenseMap<Value*, MemAccessInfo> UnderlyingObjToAccessMap;
+ UnderlyingObjToAccessMap ObjToLastAccess;
+
+ // Set of access to check after all writes have been processed.
+ PtrAccessSet DeferredAccesses;
+
+ // Iterate over each alias set twice, once to process read/write pointers,
+ // and then to process read-only pointers.
+ for (int SetIteration = 0; SetIteration < 2; ++SetIteration) {
+ bool UseDeferred = SetIteration > 0;
+ PtrAccessSet &S = UseDeferred ? DeferredAccesses : Accesses;
+
+ for (auto A : AS) {
+ Value *Ptr = A.getValue();
+ bool IsWrite = S.count(MemAccessInfo(Ptr, true));
+
+ // If we're using the deferred access set, then it contains only reads.
+ bool IsReadOnlyPtr = ReadOnlyPtr.count(Ptr) && !IsWrite;
+ if (UseDeferred && !IsReadOnlyPtr)
+ continue;
+ // Otherwise, the pointer must be in the PtrAccessSet, either as a read
+ // or a write.
+ assert(((IsReadOnlyPtr && UseDeferred) || IsWrite ||
+ S.count(MemAccessInfo(Ptr, false))) &&
+ "Alias-set pointer not in the access set?");
+
+ MemAccessInfo Access(Ptr, IsWrite);
+ DepCands.insert(Access);
+
+ // Memorize read-only pointers for later processing and skip them in the
+ // first round (they need to be checked after we have seen all write
+ // pointers). Note: we also mark pointer that are not consecutive as
+ // "read-only" pointers (so that we check "a[b[i]] +="). Hence, we need
+ // the second check for "!IsWrite".
+ if (!UseDeferred && IsReadOnlyPtr) {
+ DeferredAccesses.insert(Access);
+ continue;
+ }