Re: [PATCH] Fix PR ipa/65908.

[Martin Liška <mliska at suse dot cz>]

On 06/10/2015 01:50 PM, Martin Liška wrote:
> On 05/15/2015 08:52 PM, Jan Hubicka wrote:
>>> +/* Return true if DECL_ARGUMENT types are valid to be merged.  */
>> Perhaps bettter as
>>
>> Perform additional check needed to match types function parameters that are
>> used.  Unlike for normal parameters it matters if type is TYPE_RESTRICT and we
>> make an assumption that REFERENCE_TYPE parameters are always non-NULL.
>>
>>> +
>>> +bool
>>> +sem_function::compatible_parm_types_p ()
>>> +{
>>> +  tree parm1, parm2;
>>> +  unsigned i = 0;
>>> +
>>> +  for (parm1 = DECL_ARGUMENTS (decl),
>>> +       parm2 = DECL_ARGUMENTS (m_compared_func->decl);
>>> +       parm1 && parm2;
>>> +       parm1 = DECL_CHAIN (parm1), parm2 = DECL_CHAIN (parm2), i++)
>>
>> I think this is still not right.  What you wan to to do is to have
>>
>> 1) comparible_parm_types_p (t1,t2, index) that returns true if T1 and T2 are
>>    matching with checks bellow:
>>> +  {
>>> +    if (!param_used_p (i))
>>> +      continue;
>>> +
>>> +    if (POINTER_TYPE_P (parm1)
>>> +	&& (TYPE_RESTRICT (parm1) != TYPE_RESTRICT (parm2)))
>>> +      return return_false_with_msg ("argument restrict flag mismatch");
>>> +    /* nonnull_arg_p implies non-zero range to REFERENCE types.  */
>>> +    if (POINTER_TYPE_P (parm1)
>>> +	&& TREE_CODE (parm1) != TREE_CODE (parm2)
>>> +	&& opt_for_fn (decl, flag_delete_null_pointer_checks))
>>> +      return return_false_with_msg ("pointer wrt reference mismatch");
>>> +  }
>>    withtout actually walking the chain.
>>
>> 2) make equals_wpa to walk TYPE_ARG_TYPES of the function type and match them.
>>    This is because DECL_ARGUMENTS are part of function body and before you
>>    read it into memory, these are NULL
>>
>>    Walking DECL_ARGUMENTS here may cause ipa-icf to give up in case one body is
>>    read (and thus have some arguments) and other is not.
>>
>> 3) make equals_private walk DECL_ARGUMENTS and match them
>>    (well at the time you populate the map.)
>>    You probalby can skip matching PARM_DECLS that are !parm_used_p (i)
>>    for anything else than types_compatible_p.
>>
>>    We only care they are passed the same way by ABI. Everything else is not
>>    relevant.
>>
>> Honza
>>
> 
> Hi Honza.
> 
> I forgot a bit about the patch.
> Please check updated version of the patch which can boostrap and survives
> regression tests.
> 
> Martin
> 

As we're planning to release 5.2 soon, I ping the patch.

Martin