[DirectX] add "llvm.loop" to metadata whitelist

Author: inbelic

llvm/lib/Target/DirectX/DXILTranslateMetadata.cpp

@@ -294,16 +294,17 @@ static void translateBranchMetadata(Module &M, Instruction *BBTerminatorInst) {
   BBTerminatorInst->setMetadata("hlsl.controlflow.hint", nullptr);
 }
 
-static std::array<unsigned, 6> getCompatibleInstructionMDs(llvm::Module &M) {
+static std::array<unsigned, 7> getCompatibleInstructionMDs(llvm::Module &M) {
   return {
       M.getMDKindID("dx.nonuniform"),    M.getMDKindID("dx.controlflow.hints"),
       M.getMDKindID("dx.precise"),       llvm::LLVMContext::MD_range,
-      llvm::LLVMContext::MD_alias_scope, llvm::LLVMContext::MD_noalias};
+      llvm::LLVMContext::MD_alias_scope, llvm::LLVMContext::MD_noalias,
+      M.getMDKindID("llvm.loop")};
 }
 
 static void translateInstructionMetadata(Module &M) {
   // construct allowlist of valid metadata node kinds
-  std::array<unsigned, 6> DXILCompatibleMDs = getCompatibleInstructionMDs(M);
+  std::array<unsigned, 7> DXILCompatibleMDs = getCompatibleInstructionMDs(M);
 
   for (Function &F : M) {
     for (BasicBlock &BB : F) {