c++: Simplify build_over_call a bit.

It occurred to me that if we're looking up the defining base within the
conversion_path binfo, we could use the result for the conversion as well
instead of doing two separate conversions.

gcc/cp/ChangeLog:

	* call.c (build_over_call): Only call build_base_path once.

diff --git a/gcc/cp/call.c b/gcc/cp/call.c
index fe68fda..d8923be 100644 (file)
--- a/gcc/cp/call.c
+++ b/gcc/cp/call.c
@@ -8658,13 +8658,10 @@ build_over_call (struct z_candidate *cand, int flags, tsubst_flags_t complain)
   /* Bypass access control for 'this' parameter.  */
   else if (TREE_CODE (TREE_TYPE (fn)) == METHOD_TYPE)
     {
-      tree parmtype = TREE_VALUE (parm);
       tree arg = build_this (first_arg != NULL_TREE
                             ? first_arg
                             : (*args)[arg_index]);
       tree argtype = TREE_TYPE (arg);
-      tree converted_arg;
-      tree base_binfo;
 
       if (arg == error_mark_node)
        return error_mark_node;
@@ -8683,38 +8680,20 @@ build_over_call (struct z_candidate *cand, int flags, tsubst_flags_t complain)
            return error_mark_node;
        }
 
+      /* The class where FN is defined.  */
+      tree ctx = DECL_CONTEXT (fn);
+
       /* See if the function member or the whole class type is declared
         final and the call can be devirtualized.  */
-      if (DECL_FINAL_P (fn)
-         || CLASSTYPE_FINAL (TYPE_METHOD_BASETYPE (TREE_TYPE (fn))))
+      if (DECL_FINAL_P (fn) || CLASSTYPE_FINAL (ctx))
        flags |= LOOKUP_NONVIRTUAL;
 
-      /* If we know the dynamic type of the object, look up the final overrider
-        in the BINFO.  */
-      if (DECL_VINDEX (fn) && (flags & LOOKUP_NONVIRTUAL) == 0
-         && resolves_to_fixed_type_p (arg))
-       {
-         tree binfo = cand->conversion_path;
-         if (BINFO_TYPE (binfo) != DECL_CONTEXT (fn))
-           binfo = lookup_base (binfo, DECL_CONTEXT (fn), ba_unique,
-                                NULL, complain);
-         fn = lookup_vfn_in_binfo (DECL_VINDEX (fn), binfo);
-         flags |= LOOKUP_NONVIRTUAL;
-       }
-
       /* [class.mfct.non-static]: If a non-static member function of a class
         X is called for an object that is not of type X, or of a type
         derived from X, the behavior is undefined.
 
         So we can assume that anything passed as 'this' is non-null, and
         optimize accordingly.  */
-      gcc_assert (TYPE_PTR_P (parmtype));
-      /* Convert to the base in which the function was declared.  */
-      gcc_assert (cand->conversion_path != NULL_TREE);
-      converted_arg = build_base_path (PLUS_EXPR,
-                                      arg,
-                                      cand->conversion_path,
-                                      1, complain);
       /* Check that the base class is accessible.  */
       if (!accessible_base_p (TREE_TYPE (argtype),
                              BINFO_TYPE (cand->conversion_path), true))
@@ -8728,12 +8707,25 @@ build_over_call (struct z_candidate *cand, int flags, tsubst_flags_t complain)
        }
       /* If fn was found by a using declaration, the conversion path
         will be to the derived class, not the base declaring fn. We
-        must convert from derived to base.  */
-      base_binfo = lookup_base (TREE_TYPE (TREE_TYPE (converted_arg)),
-                               TREE_TYPE (parmtype), ba_unique,
-                               NULL, complain);
-      converted_arg = build_base_path (PLUS_EXPR, converted_arg,
-                                      base_binfo, 1, complain);
+        must convert to the base.  */
+      tree base_binfo = cand->conversion_path;
+      if (BINFO_TYPE (base_binfo) != ctx)
+       {
+         base_binfo = lookup_base (base_binfo, ctx, ba_unique, NULL, complain);
+         if (base_binfo == error_mark_node)
+           return error_mark_node;
+       }
+      tree converted_arg = build_base_path (PLUS_EXPR, arg,
+                                           base_binfo, 1, complain);
+
+      /* If we know the dynamic type of the object, look up the final overrider
+        in the BINFO.  */
+      if (DECL_VINDEX (fn) && (flags & LOOKUP_NONVIRTUAL) == 0
+         && resolves_to_fixed_type_p (arg))
+       {
+         fn = lookup_vfn_in_binfo (DECL_VINDEX (fn), base_binfo);
+         flags |= LOOKUP_NONVIRTUAL;
+       }
 
       argarray[j++] = converted_arg;
       parm = TREE_CHAIN (parm);