Two changes:
1. Chain to the parent implementation of M/R analysis if we can't find
any information. It has some heuristics that often do well.
2. Do not clear all flags, this can make invalid nodes by turning nodes
that used to be collapsed into non-collapsed nodes (fixing crashes)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@20659 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/DataStructure/DataStructureAA.cpp b/lib/Analysis/DataStructure/DataStructureAA.cpp
index 62eb663..74fdb1f 100644
--- a/lib/Analysis/DataStructure/DataStructureAA.cpp
+++ b/lib/Analysis/DataStructure/DataStructureAA.cpp
@@ -174,13 +174,13 @@
AliasAnalysis::ModRefResult
DSAA::getModRefInfo(CallSite CS, Value *P, unsigned Size) {
Function *F = CS.getCalledFunction();
- if (!F) return pointsToConstantMemory(P) ? Ref : ModRef;
- if (F->isExternal()) return ModRef;
+ if (!F || F->isExternal())
+ return AliasAnalysis::getModRefInfo(CS, P, Size);
// Clone the function TD graph, clearing off Mod/Ref flags
const Function *csParent = CS.getInstruction()->getParent()->getParent();
DSGraph TDGraph(TD->getDSGraph(*csParent));
- TDGraph.maskNodeTypes(0);
+ TDGraph.maskNodeTypes(~(DSNode::Modified|DSNode::Read));
// Insert the callee's BU graph into the TD graph
const DSGraph &BUGraph = BU->getDSGraph(*F);