Ignore unreachable blocks when doing memory dependence analysis on non-local
loads. It's not really profitable and may result in GVN going into an infinite
loop when it hits constructs like this:
%x = gep %some.type %x, ...
Found via an LTO build of LLVM.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166490 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/MemoryDependenceAnalysis.cpp b/lib/Analysis/MemoryDependenceAnalysis.cpp
index 9316df6..9872890 100644
--- a/lib/Analysis/MemoryDependenceAnalysis.cpp
+++ b/lib/Analysis/MemoryDependenceAnalysis.cpp
@@ -983,7 +983,7 @@
for (NonLocalDepInfo::iterator I = Cache->begin(), E = Cache->end();
I != E; ++I) {
Visited.insert(std::make_pair(I->getBB(), Addr));
- if (!I->getResult().isNonLocal())
+ if (!I->getResult().isNonLocal() && DT->isReachableFromEntry(I->getBB()))
Result.push_back(NonLocalDepResult(I->getBB(), I->getResult(), Addr));
}
++NumCacheCompleteNonLocalPtr;
@@ -1029,7 +1029,7 @@
NumSortedEntries);
// If we got a Def or Clobber, add this to the list of results.
- if (!Dep.isNonLocal()) {
+ if (!Dep.isNonLocal() && DT->isReachableFromEntry(BB)) {
Result.push_back(NonLocalDepResult(BB, Dep, Pointer.getAddr()));
continue;
}