reject invalid comma stuff with a message.  We reject the case in
PR6888 with:

$ llvm-as t.ll
llvm-as: t.ll:2:29: error: expected metadata or 'align'
 store <3 x i32> %x, i32 1, i32 1>, <3 x i32>* %p
                            ^

instead of:

$ llvm-as t.ll 
llvm-as: 


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@102154 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AsmParser/LLParser.cpp b/lib/AsmParser/LLParser.cpp
index aa887d2..45b88cc 100644
--- a/lib/AsmParser/LLParser.cpp
+++ b/lib/AsmParser/LLParser.cpp
@@ -1170,10 +1170,10 @@
       return false;
     }
     
-    if (Lex.getKind() == lltok::kw_align) {
-      if (ParseOptionalAlignment(Alignment)) return true;
-    } else
-      return true;
+    if (Lex.getKind() != lltok::kw_align)
+      return Error(Lex.getLoc(), "expected metadata or 'align'");
+    
+    if (ParseOptionalAlignment(Alignment)) return true;
   }
 
   return false;