[rth, see below]

>> Index: gcc/attribs.c
>> ===================================================================
>> --- gcc/attribs.c       (.../trunk)     (revision 180744)
>> +++ gcc/attribs.c       (.../branches/transactional-memory)     (revision
>> 180773)
>> @@ -166,7 +166,8 @@ init_attributes (void)
>>           gcc_assert (strcmp (attribute_tables[i][j].name,
>>                               attribute_tables[i][k].name));
>>      }
>> -  /* Check that no name occurs in more than one table.  */
>> +  /* Check that no name occurs in more than one table.  Names that
>> +     begin with '*' are exempt, and may be overridden.  */
>>    for (i = 0; i<  ARRAY_SIZE (attribute_tables); i++)
>>      {
>>        size_t j, k, l;
>> @@ -174,8 +175,9 @@ init_attributes (void)
>>        for (j = i + 1; j<  ARRAY_SIZE (attribute_tables); j++)
>>         for (k = 0; attribute_tables[i][k].name != NULL; k++)
>>           for (l = 0; attribute_tables[j][l].name != NULL; l++)
>> -           gcc_assert (strcmp (attribute_tables[i][k].name,
>> -                               attribute_tables[j][l].name));
>> +           gcc_assert (attribute_tables[i][k].name[0] == '*'
>> +                       || strcmp (attribute_tables[i][k].name,
>> +                                  attribute_tables[j][l].name));
>>      }
>>   #endif
>>
>> @@ -207,7 +209,7 @@ register_attribute (const struct attribu
>>    slot = htab_find_slot_with_hash (attribute_hash,&str,
>>                                    substring_hash (str.str, str.length),
>>                                    INSERT);
>> -  gcc_assert (!*slot);
>> +  gcc_assert (!*slot || attr->name[0] == '*');
>>    *slot = (void *) CONST_CAST (struct attribute_spec *, attr);
>>   }
>
> The above changes seem to belong to a different changeset and look
> strange.  Why would attributes ever appear in two different tables?

I couldn't find a corresponding gcc-patches message for this patch, but 
I was able to hunt down full the patch, which I am attaching for discussion.

This seems to be a change required for allowing '*' to override 
builtins, so it is indeed part of the branch.  Perhaps with the full 
context it is easier to review.

I will defer to rth to answer any questions on the original motivation.

Richi, do you have any particular issue with the attribs.c change?  Does 
this context resolve any questions you may have had?

Aldy