- ValueCacheEntryTy &Cache = lookup(Val);
- SeenBlocks.insert(BB);
- LVILatticeVal &BBLV = Cache[BB];
-
- // OverDefinedCacheUpdater is a helper object that will update
- // the OverDefinedCache for us when this method exits. Make sure to
- // call markResult on it as we exist, passing a bool to indicate if the
- // cache needs updating, i.e. if we have solve a new value or not.
- OverDefinedCacheUpdater ODCacheUpdater(Val, BB, BBLV, this);
-
- // Once this BB is encountered, Val's value for this BB will not be Undefined
- // any longer. When we encounter this BB again, if Val's value is Overdefined,
- // we need to compute its value again.
- //
- // For example, considering this control flow,
- // BB1->BB2, BB1->BB3, BB2->BB3, BB2->BB4
- //
- // Suppose we have "icmp slt %v, 0" in BB1, and "icmp sgt %v, 0" in BB3. At
- // the very beginning, when analyzing edge BB2->BB3, we don't know %v's value
- // in BB2, and the data flow algorithm tries to compute BB2's predecessors, so
- // then we know %v has negative value on edge BB1->BB2. And then we return to
- // check BB2 again, and at this moment BB2 has Overdefined value for %v in
- // BB2. So we should have to follow data flow propagation algorithm to get the
- // value on edge BB1->BB2 propagated to BB2, and finally %v on BB2 has a
- // constant range describing a negative value.
-
- if (!BBLV.isUndefined() && !BBLV.isOverdefined()) {
- DEBUG(dbgs() << " reuse BB '" << BB->getName() << "' val=" << BBLV <<'\n');
-
- // Since we're reusing a cached value here, we don't need to update the
- // OverDefinedCahce. The cache will have been properly updated
- // whenever the cached value was inserted.
- ODCacheUpdater.markResult(false);
+ if (lookup(Val).count(BB)) {
+ // If we have a cached value, use that.
+ DEBUG(dbgs() << " reuse BB '" << BB->getName()
+ << "' val=" << lookup(Val)[BB] << '\n');
+
+ // Since we're reusing a cached value, we don't need to update the
+ // OverDefinedCache. The cache will have been properly updated whenever the
+ // cached value was inserted.