add fixme for dubious code. Duncan, what do you think?

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89602 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Analysis/BasicAliasAnalysis.cpp

@@ -263,6 +263,7 @@ ImmutablePass *llvm::createBasicAliasAnalysisPass() {
 bool BasicAliasAnalysis::pointsToConstantMemory(const Value *P) {
   if (const GlobalVariable *GV = 
         dyn_cast<GlobalVariable>(P->getUnderlyingObject()))
+    // FIXME: shouldn't this require GV to be "ODR"?
     return GV->isConstant();
   return false;
 }