+
+void llvm::combineMetadata(Instruction *K, const Instruction *J,
+ ArrayRef<unsigned> KnownIDs) {
+ SmallVector<std::pair<unsigned, MDNode *>, 4> Metadata;
+ K->dropUnknownNonDebugMetadata(KnownIDs);
+ K->getAllMetadataOtherThanDebugLoc(Metadata);
+ for (unsigned i = 0, n = Metadata.size(); i < n; ++i) {
+ unsigned Kind = Metadata[i].first;
+ MDNode *JMD = J->getMetadata(Kind);
+ MDNode *KMD = Metadata[i].second;
+
+ switch (Kind) {
+ default:
+ K->setMetadata(Kind, nullptr); // Remove unknown metadata
+ break;
+ case LLVMContext::MD_dbg:
+ llvm_unreachable("getAllMetadataOtherThanDebugLoc returned a MD_dbg");
+ case LLVMContext::MD_tbaa:
+ K->setMetadata(Kind, MDNode::getMostGenericTBAA(JMD, KMD));
+ break;
+ case LLVMContext::MD_alias_scope:
+ K->setMetadata(Kind, MDNode::getMostGenericAliasScope(JMD, KMD));
+ break;
+ case LLVMContext::MD_noalias:
+ K->setMetadata(Kind, MDNode::intersect(JMD, KMD));
+ break;
+ case LLVMContext::MD_range:
+ K->setMetadata(Kind, MDNode::getMostGenericRange(JMD, KMD));
+ break;
+ case LLVMContext::MD_fpmath:
+ K->setMetadata(Kind, MDNode::getMostGenericFPMath(JMD, KMD));
+ break;
+ case LLVMContext::MD_invariant_load:
+ // Only set the !invariant.load if it is present in both instructions.
+ K->setMetadata(Kind, JMD);
+ break;
+ case LLVMContext::MD_nonnull:
+ // Only set the !nonnull if it is present in both instructions.
+ K->setMetadata(Kind, JMD);
+ break;
+ case LLVMContext::MD_invariant_group:
+ // Preserve !invariant.group in K.
+ break;
+ case LLVMContext::MD_align:
+ K->setMetadata(Kind,
+ MDNode::getMostGenericAlignmentOrDereferenceable(JMD, KMD));
+ break;
+ case LLVMContext::MD_dereferenceable:
+ case LLVMContext::MD_dereferenceable_or_null:
+ K->setMetadata(Kind,
+ MDNode::getMostGenericAlignmentOrDereferenceable(JMD, KMD));
+ break;
+ }
+ }
+ // Set !invariant.group from J if J has it. If both instructions have it
+ // then we will just pick it from J - even when they are different.
+ // Also make sure that K is load or store - f.e. combining bitcast with load
+ // could produce bitcast with invariant.group metadata, which is invalid.
+ // FIXME: we should try to preserve both invariant.group md if they are
+ // different, but right now instruction can only have one invariant.group.
+ if (auto *JMD = J->getMetadata(LLVMContext::MD_invariant_group))
+ if (isa<LoadInst>(K) || isa<StoreInst>(K))
+ K->setMetadata(LLVMContext::MD_invariant_group, JMD);
+}
+
+unsigned llvm::replaceDominatedUsesWith(Value *From, Value *To,
+ DominatorTree &DT,
+ const BasicBlockEdge &Root) {
+ assert(From->getType() == To->getType());
+
+ unsigned Count = 0;
+ for (Value::use_iterator UI = From->use_begin(), UE = From->use_end();
+ UI != UE; ) {
+ Use &U = *UI++;
+ if (DT.dominates(Root, U)) {
+ U.set(To);
+ DEBUG(dbgs() << "Replace dominated use of '"
+ << From->getName() << "' as "
+ << *To << " in " << *U << "\n");
+ ++Count;
+ }
+ }
+ return Count;
+}
+
+unsigned llvm::replaceDominatedUsesWith(Value *From, Value *To,
+ DominatorTree &DT,
+ const BasicBlock *BB) {
+ assert(From->getType() == To->getType());
+
+ unsigned Count = 0;
+ for (Value::use_iterator UI = From->use_begin(), UE = From->use_end();
+ UI != UE;) {
+ Use &U = *UI++;
+ auto *I = cast<Instruction>(U.getUser());
+ if (DT.dominates(BB, I->getParent())) {
+ U.set(To);
+ DEBUG(dbgs() << "Replace dominated use of '" << From->getName() << "' as "
+ << *To << " in " << *U << "\n");
+ ++Count;
+ }
+ }
+ return Count;
+}
+
+bool llvm::callsGCLeafFunction(ImmutableCallSite CS) {
+ if (isa<IntrinsicInst>(CS.getInstruction()))
+ // Most LLVM intrinsics are things which can never take a safepoint.
+ // As a result, we don't need to have the stack parsable at the
+ // callsite. This is a highly useful optimization since intrinsic
+ // calls are fairly prevalent, particularly in debug builds.
+ return true;
+
+ // Check if the function is specifically marked as a gc leaf function.
+ if (CS.hasFnAttr("gc-leaf-function"))
+ return true;
+ if (const Function *F = CS.getCalledFunction())
+ return F->hasFnAttribute("gc-leaf-function");
+
+ return false;
+}