On Sat, Nov 5, 2011 at 10:05 PM, Aldy Hernandez <al...@redhat.com> wrote:
> [rth, see below]
>
>>> local_define_builtin ("__builtin_eh_pointer", ftype,
>>> BUILT_IN_EH_POINTER,
>>> "__builtin_eh_pointer", ECF_PURE | ECF_NOTHROW |
>>> ECF_LEAF);
>>> + if (flag_tm)
>>> + apply_tm_attr (builtin_decl_explicit (BUILT_IN_EH_POINTER),
>>> + get_identifier ("transaction_pure"));
>>
>> I think this should use a new ECF_TM_PURE flag, unconditionally set
>> with handling in the functions that handle/return ECF flags so that
>> transitioning this to a tree node flag instead of an attribute is easier.
>
> I could add a ECF_TM_PURE flag and attach it to the BUILT_IN_EH_POINTER in
> the local_define_builtin above, but we still need the attribute for function
> decl's as in:
>
> __attribute__((transaction_pure)) void foo();
>
> Attributes seem like a clean way to approach this.
The middle-end interfacing is supposed to be via ECF_ flags, the user interface
via attributes. What's the semantic of transaction-pure vs. ...
> I don't see what the flag buys us. Or am I misunderstanding something?
>
>>> +/* Nonzero if this call performs a transactional memory operation. */
>>> +#define ECF_TM_OPS (1<< 11)
>>
>> What's this flag useful for? Isn't it the case that you want to
>> conservatively
>> know whether a call might perform a tm operation? Thus, the flag
>> should be inverted? Is this the same as "TM pure"?
... this?
> Richard?
> Richi, I have fixed or addressed all the issues in this thread, with the
> exception of your EFC_TM_PURE and ECF_TM_OPS questions, which I am deferring
> to rth and then fixing if required.
Yeah, seems to be still an open question.
Thanks,
Richard.
