1 files changed, 10 insertions, 1 deletions
diff --git a/clang/lib/AST/ItaniumMangle.cpp b/clang/lib/AST/ItaniumMangle.cpp
index 9fafef13f62..64f9ccd9967 100644
--- a/clang/lib/AST/ItaniumMangle.cpp
+++ b/clang/lib/AST/ItaniumMangle.cpp
@@ -3458,8 +3458,17 @@ recurse:
     break;
       
   case Expr::SizeOfPackExprClass: {
+    auto *SPE = cast<SizeOfPackExpr>(E);
+    if (SPE->isPartiallySubstituted()) {
+      Out << "sP";
+      for (const auto &A : SPE->getPartialArguments())
+        mangleTemplateArg(A);
+      Out << "E";
+      break;
+    }
+
     Out << "sZ";
-    const NamedDecl *Pack = cast<SizeOfPackExpr>(E)->getPack();
+    const NamedDecl *Pack = SPE->getPack();
     if (const TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(Pack))
       mangleTemplateParameter(TTP->getIndex());
     else if (const NonTypeTemplateParmDecl *NTTP