Fix a really nasty caching bug I introduced in memdep. An entry

was being added to the Result vector, but not being put in the
cache.  This means that if the cache was reused wholesale for a
later query that it would be missing this entry and we'd do an
incorrect load elimination.

Unfortunately, it's not really possible to write a useful 
testcase for this, but this unbreaks 255.vortex.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@90093 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 12 insertions, 2 deletions

diff --git a/lib/Analysis/MemoryDependenceAnalysis.cpp b/lib/Analysis/MemoryDependenceAnalysis.cpp
index b5069ecbc9..49dfeb5d3f 100644
--- a/lib/Analysis/MemoryDependenceAnalysis.cpp
+++ b/lib/Analysis/MemoryDependenceAnalysis.cpp
@@ -1156,8 +1156,18 @@ getNonLocalPointerDepFromBB(Value *Pointer, uint64_t PointeeSize,
       // that predecessor.  We can still do PRE of the load, which would insert
       // a computation of the pointer in this predecessor.
       if (PredPtr == 0) {
-        Result.push_back(NonLocalDepEntry(Pred,
-                              MemDepResult::getClobber(Pred->getTerminator())));
+        // Add the entry to the Result list.
+        NonLocalDepEntry Entry(Pred,
+                               MemDepResult::getClobber(Pred->getTerminator()));
+        Result.push_back(Entry);
+
+        // Add it to the cache for this CacheKey so that subsequent queries get
+        // this result.
+        Cache = &NonLocalPointerDeps[CacheKey].second;
+        MemoryDependenceAnalysis::NonLocalDepInfo::iterator It =
+          std::upper_bound(Cache->begin(), Cache->end(), Entry);
+        Cache->insert(It, Entry);
+        Cache = 0;
         continue;
       }