[trans-mem] optimize transaction local malloc/alloca memory

[Richard Guenther]

On Fri, Dec 4, 2009 at 5:32 PM, Richard Henderson <rth@redhat.com> wrote:
> On 12/04/2009 06:26 AM, Aldy Hernandez wrote:
>>
>> +  p = malloc (sizeof (*p) * 100);
>> +
>> +  __transaction {
>> +    /* Instrument store, since memory pointed to by P is not
>> +       transaction local.  */
>> +    p[5] = 123;
>> +
>> +    if (something())
>> +      __transaction_cancel;
>> +  }
>> +  return p[5];
>> +}
>> +
>> +/* { dg-final { scan-tree-dump-times "ITM_WU" 1 "tmmark" } } */
>
> Not the best test case to add, since P is thread-private. You could
> instrument this with either a log function or a local copy.
>
>> +  if (stmt&&  is_gimple_call (stmt))
>
> Formatting.
>
>> +      if (DECL_BUILT_IN_CLASS (fn) == BUILT_IN_NORMAL
>> +       &&  (DECL_FUNCTION_CODE (fn) == BUILT_IN_MALLOC
>> +             || DECL_FUNCTION_CODE (fn) == BUILT_IN_ALLOCA))
>
> gimple_call_flags (stmt) & ECF_MALLOC

That's not a check for malloc but just for if the function returns a
pointer to non-aliased memory.  I could imagine this to trigger
falsely for user-annotated functions, so IMHO testing for the
builtins is better (where you btw miss BUILT_IN_CALLOC).

Richard.