Fix LLVMSetMetadata and LLVMAddNamedMetadataOperand for single value MDNodes

Summary:
MetadataAsValue uses a canonical format that strips the MDNode if it
contains only a single constant value. This triggers an assertion when
trying to cast the value to a MDNode.

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D7165

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227319 91177308-0d34-0410-b5e6-96231b3b80d8

tools/llvm-c-test/main.c

@@ -65,6 +65,10 @@ int main(int argc, char **argv) {
     return disassemble();
   } else if (argc == 2 && !strcmp(argv[1], "--calc")) {
     return calc();
+  } else if (argc == 2 && !strcmp(argv[1], "--add-named-metadata-operand")) {
+    return add_named_metadata_operand();
+  } else if (argc == 2 && !strcmp(argv[1], "--set-metadata")) {
+    return set_metadata();
   } else {
     print_usage();
   }