[embedded] Start flagging AllocRefDynamicInst usage in embedded Swift

Author: kubamracek

lib/SILOptimizer/Mandatory/PerformanceDiagnostics.cpp

@@ -448,7 +448,7 @@ static bool metatypeUsesAreNotRelevant(MetatypeInst *mt) {
 }
 
 static bool allowedMetadataUseInEmbeddedSwift(SILInstruction *inst) {
-  // Only diagnose metatype and value_metatype instructions, for now.
+  // Only diagnose metatype, value_metatype instructions, ...
   if ((isa<ValueMetatypeInst>(inst) || isa<MetatypeInst>(inst))) {
     auto metaTy = cast<SingleValueInstruction>(inst)->getType().castTo<MetatypeType>();
     if (metaTy->getRepresentation() == MetatypeRepresentation::Thick) {
@@ -458,6 +458,9 @@ static bool allowedMetadataUseInEmbeddedSwift(SILInstruction *inst) {
       // Class metadata are supported in embedded Swift
       return instTy->getClassOrBoundGenericClass() ? true : false;
     }
+  // ... and alloc_ref_dynamic, for now.
+  } else if (isa<AllocRefDynamicInst>(inst)) {
+    return false;
   }
 
   return true;