Revert r215343.
This was contentious and needs invesigation.
llvm-svn: 218971
diff --git a/llvm/lib/Analysis/LazyValueInfo.cpp b/llvm/lib/Analysis/LazyValueInfo.cpp
index 961fb0f..414aaab 100644
--- a/llvm/lib/Analysis/LazyValueInfo.cpp
+++ b/llvm/lib/Analysis/LazyValueInfo.cpp
@@ -545,31 +545,7 @@
// 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.
- //
- // In the mean time, limit the number of additional lowering lattice value to
- // avoid unjustified memory grows.
-
- if (LoweringOverdefinedTimes.count(BB) == 0)
- LoweringOverdefinedTimes.insert(std::make_pair(BB, 0));
- if ((!BBLV.isUndefined() && !BBLV.isOverdefined()) ||
- (BBLV.isOverdefined() &&
- (LoweringOverdefinedTimes[BB] > OverdefinedThreshold ||
- LoweringOverdefinedTimes.size() > OverdefinedBBThreshold))) {
+ if (!BBLV.isUndefined()) {
DEBUG(dbgs() << " reuse BB '" << BB->getName() << "' val=" << BBLV <<'\n');
// Since we're reusing a cached value here, we don't need to update the