Re: User directed Function Multiversioning via Function Overloading (issue5752064)

[Jason Merrill]

On 11/09/2012 08:33 PM, Sriraman Tallam wrote:
+         /* Skip calling decls_match for versioned functions.  */
+          if (DECL_FUNCTION_VERSIONED (fn)
+             && DECL_FUNCTION_VERSIONED (TREE_PURPOSE (match)))
+           continue;
+         if (!decls_match (fn, TREE_PURPOSE (match)))
+            break;

This seems like it would allow multiple versioned functions from 
different namespaces; I want to allow mismatches only if they are 
versions of the same function.  I was thinking

         for (match = TREE_CHAIN (matches); match; match = TREE_CHAIN 
(match))
            if (!decls_match (fn, TREE_PURPOSE (match))
                && !targetm.target_option.function_versions (fn, 
TREE_PURPOSE (match)))
              break;

+      error_at (input_location, "Call/Pointer to multiversioned function"
+                " without a default cannot be dispatched");

Let's just say "use of multiversioned  function without a default".

Jason