Re: [PATCH] lower-subreg: PR94123, SVN r273240, causes gcc.target/powerpc/pr87507.c to fail

[Richard Sandiford <richard.sandiford@arm.com>]

Peter Bergner <bergner@linux.ibm.com> writes:
> On 3/30/20 3:50 AM, Richard Sandiford wrote:
>> Peter Bergner via Gcc-patches <gcc-patches@gcc.gnu.org> writes:
>>> 	* lower-subreg.c (pass_lower_subreg3::gate): Remove test for
>>> 	flag_split_wide_types_early.
>>>
>>> diff --git a/gcc/lower-subreg.c b/gcc/lower-subreg.c
>>> index 4c8bc835f93..807ad398b64 100644
>>> --- a/gcc/lower-subreg.c
>>> +++ b/gcc/lower-subreg.c
>>> @@ -1844,8 +1844,7 @@ public:
>>>    {}
>>>  
>>>    /* opt_pass methods: */
>>> -  virtual bool gate (function *) { return flag_split_wide_types
>>> -					  && !flag_split_wide_types_early; }
>>> +  virtual bool gate (function *) { return flag_split_wide_types != 0; }
>>>    virtual unsigned int execute (function *)
>>>      {
>>>        decompose_multiword_subregs (true);
>> 
>> Looks good to me with the s/ != 0// that Segher mentioned.
>> 
>> With this change, the only remaining function of -fsplit-wide-types-early
>> is to act as a double lock on one pass.  IMO it'd make more sense to remove
>> that double lock and make -fsplit-wide-types-early and -fsplit-wide-types
>> act as independent options, a bit like -fschedule-insns{,2}.
>
> Have we come to consensus on whether to split the options or not?
> I think Segher is against it given we actually have 3 passes of
> lower-subreg and -fsplit-wide-types would control the 1st and 3rd
> passes and -fsplit-wide-types-early would control the second.
> That does seem strange to me too.

I guess the name of the option is a bit weird, since it'll control
the middle pass of three.  That's going to be true either way though.

We're talking about having independent options controlling independent
passes, which seems like a Good Thing in general and doesn't seem that
strange to me in this case.  But I'm certainly happy to yield given the
strong opinions the other way.

Thanks,
Richard