ObjectSizeOffsetEvaluator: Don't run into infinite recursion if we have a cyclic GEP.
Those can occur in dead code. PR17402.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191644 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/MemoryBuiltins.cpp b/lib/Analysis/MemoryBuiltins.cpp
index e710a99..8e89aa9 100644
--- a/lib/Analysis/MemoryBuiltins.cpp
+++ b/lib/Analysis/MemoryBuiltins.cpp
@@ -634,13 +634,15 @@
if (Instruction *I = dyn_cast<Instruction>(V))
Builder.SetInsertPoint(I);
- // record the pointers that were handled in this run, so that they can be
- // cleaned later if something fails
- SeenVals.insert(V);
-
// now compute the size and offset
SizeOffsetEvalType Result;
- if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
+
+ // Record the pointers that were handled in this run, so that they can be
+ // cleaned later if something fails. We also use this set to break cycles that
+ // can occur in dead code.
+ if (!SeenVals.insert(V)) {
+ Result = unknown();
+ } else if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
Result = visitGEPOperator(*GEP);
} else if (Instruction *I = dyn_cast<Instruction>(V)) {
Result = visit(*I);