[llvm-commits] [llvm] r90093 - /llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp

[Chris Lattner]

Author: lattner
Date: Sun Nov 29 15:09:36 2009
New Revision: 90093

URL: http://llvm.org/viewvc/llvm-project?rev=90093&view=rev
Log:
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.


Modified:
    llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp

Modified: llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp?rev=90093&r1=90092&r2=90093&view=diff

==============================================================================
--- llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp (original)
+++ llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp Sun Nov 29 15:09:36 2009
@@ -1156,8 +1156,18 @@
       // 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;
       }