}
// Scan the function bodies for explicit loads or stores.
- for (unsigned i = 0, e = SCC.size(); i != e && FunctionEffect != ModRef;
- ++i)
- for (inst_iterator II = inst_begin(SCC[i]->getFunction()),
- E = inst_end(SCC[i]->getFunction());
- II != E && FunctionEffect != ModRef; ++II)
- if (LoadInst *LI = dyn_cast<LoadInst>(&*II)) {
+ for (auto *Node : SCC) {
+ if (FunctionEffect == ModRef)
+ break; // The mod/ref lattice saturates here.
+ for (Instruction &I : inst_range(Node->getFunction())) {
+ if (FunctionEffect == ModRef)
+ break; // The mod/ref lattice saturates here.
+
+ // We handle calls specially because the graph-relevant aspects are
+ // handled above.
+ if (auto CS = CallSite(&I)) {
+ if (isAllocationFn(&I, TLI) || isFreeCall(&I, TLI)) {
+ // FIXME: It is completely unclear why this is necessary and not
+ // handled by the above graph code.
+ FunctionEffect |= ModRef;
+ } else if (Function *Callee = CS.getCalledFunction()) {
+ // The callgraph doesn't include intrinsic calls.
+ if (Callee->isIntrinsic()) {
+ ModRefBehavior Behaviour =
+ AliasAnalysis::getModRefBehavior(Callee);
+ FunctionEffect |= (Behaviour & ModRef);
+ }
+ }
+ continue;
+ }
+
+ // All non-call instructions we use the primary predicates for whether
+ // thay read or write memory.
+ if (I.mayReadFromMemory())
FunctionEffect |= Ref;
- if (LI->isVolatile())
- // Volatile loads may have side-effects, so mark them as writing
- // memory (for example, a flag inside the processor).
- FunctionEffect |= Mod;
- } else if (StoreInst *SI = dyn_cast<StoreInst>(&*II)) {
+ if (I.mayWriteToMemory())
FunctionEffect |= Mod;
- if (SI->isVolatile())
- // Treat volatile stores as reading memory somewhere.
- FunctionEffect |= Ref;
- } else if (isAllocationFn(&*II, TLI) || isFreeCall(&*II, TLI)) {
- FunctionEffect |= ModRef;
- } else if (IntrinsicInst *Intrinsic = dyn_cast<IntrinsicInst>(&*II)) {
- // The callgraph doesn't include intrinsic calls.
- Function *Callee = Intrinsic->getCalledFunction();
- ModRefBehavior Behaviour = AliasAnalysis::getModRefBehavior(Callee);
- FunctionEffect |= (Behaviour & ModRef);
- }
+ }
+ }
if ((FunctionEffect & Mod) == 0)
++NumReadMemFunctions;