Ok, the assertion was bogus. Calls that do not read/write memory should not

have an alias set, just like adds and subtracts don't.

llvm-svn: 12422

1 files changed, 6 insertions, 0 deletions

diff --git a/llvm/lib/Analysis/AliasSetTracker.cpp b/llvm/lib/Analysis/AliasSetTracker.cpp
index 450ba935bc0..0fb419266ce 100644
--- a/llvm/lib/Analysis/AliasSetTracker.cpp
+++ b/llvm/lib/Analysis/AliasSetTracker.cpp
@@ -117,6 +117,8 @@ void AliasSet::addCallSite(CallSite CS, AliasAnalysis &AA) {
 bool AliasSet::aliasesPointer(const Value *Ptr, unsigned Size,
                               AliasAnalysis &AA) const {
   if (AliasTy == MustAlias) {
+    assert(CallSites.empty() && "Illegal must alias set!");
+
     // If this is a set of MustAliases, only check to see if the pointer aliases
     // SOME value in the set...
     HashNodePair *SomePtr = getSomePointer();
@@ -222,6 +224,10 @@ void AliasSetTracker::add(StoreInst *SI) {
 
 
 void AliasSetTracker::add(CallSite CS) {
+  if (Function *F = CS.getCalledFunction())
+    if (AA.doesNotAccessMemory(F))
+      return;
+
   AliasSet *AS = findAliasSetForCallSite(CS);
   if (!AS) {
     AliasSets.push_back(AliasSet());