add support for PHI nodes to ObjectSizeOffsetVisitor
llvm-svn: 171298
diff --git a/llvm/lib/Analysis/MemoryBuiltins.cpp b/llvm/lib/Analysis/MemoryBuiltins.cpp
index cfd8fcf..2503bfa 100644
--- a/llvm/lib/Analysis/MemoryBuiltins.cpp
+++ b/llvm/lib/Analysis/MemoryBuiltins.cpp
@@ -535,9 +535,20 @@
return unknown();
}
-SizeOffsetType ObjectSizeOffsetVisitor::visitPHINode(PHINode&) {
- // too complex to analyze statically.
- return unknown();
+SizeOffsetType ObjectSizeOffsetVisitor::visitPHINode(PHINode &PHI) {
+ if (PHI.getNumIncomingValues() == 0)
+ return unknown();
+
+ SizeOffsetType Ret = compute(PHI.getIncomingValue(0));
+ if (!bothKnown(Ret))
+ return unknown();
+
+ // verify that all PHI incoming pointers have the same size and offset
+ for (unsigned i = 1, e = PHI.getNumIncomingValues(); i != e; ++i) {
+ if (compute(PHI.getIncomingValue(i)) != Ret)
+ return unknown();
+ }
+ return Ret;
}
SizeOffsetType ObjectSizeOffsetVisitor::visitSelectInst(SelectInst &I) {