[GlobalsModRef] Remove check for allocator calls

[nikic]

Summary

As the FIXME already indicates, I don't see why this code would be necessary. If there's a call to an allocator function, that should get treated just like any other function call -- usually it will be a declaration and handled conservatively based on memory attributes only. There should be no need to explicitly force it to be modref. No test failures either, so I think this is just dead code.

[fhahn]

LGTM, thanks!

llvm/lib/Analysis/GlobalsModRef.cpp

for (auto *Node : SCC) {
 
       for (Instruction &I : instructions(Node->getFunction())) {
         if (isModAndRefSet(FI.getModRefInfo()))
           break; // The mod/ref lattice saturates here.
 
         // We handle calls specially because the graph-relevant aspects are
         // handled above.
         if (auto *Call = dyn_cast<CallBase>(&I)) {
-          auto &TLI = GetTLI(*Node->getFunction());
-          if (isAllocationFn(Call, &TLI) || isFreeCall(Call, &TLI)) {
-            // FIXME: It is completely unclear why this is necessary and not
-            // handled by the above graph code.
-            FI.addModRefInfo(ModRefInfo::ModRef);
-          } else if (Function *Callee = Call->getCalledFunction()) {
+          if (Function *Callee = Call->getCalledFunction()) {
             // The callgraph doesn't include intrinsic calls.
             if (Callee->isIntrinsic()) {
               if (isa<DbgInfoIntrinsic>(Call))
                 // Don't let dbg intrinsics affect alias info.
                 continue;
 
               FunctionModRefBehavior Behaviour =
                   AAResultBase::getModRefBehavior(Callee);