Re: [PATCH,RS6000 2/5] Rework the RS6000_BTM defines.

[will schmidt <will_schmidt@vnet.ibm.com>]

On Tue, 2022-06-07 at 10:50 +0800, Kewen.Lin wrote:
> Hi Will,


Hi!

> 
> The whole series looks good to me, thanks!

:-)

>                                 IMHO one place can be
> further
refactored, not sure if it's worth to updating together in
> this series, it's ...

Additional comments below.  
I've made note of the comments, and request (ask) that this be
approved, with a pinky promise that I intend to follow up on the
suggestions in my next patch series.


> 
> on 2022/6/7 06:05, will schmidt wrote:
> > [PATCH,RS6000 2/5) Rework the RS6000_BTM defines.
> > 
> > The RS6000_BTM_<xxxx> definitions are mostly unused after the
> > rs6000
> > builtin code was reworked.  The remaining references can be
> > replaced
> > with the OPTION_MASK_<xxxx> and MASK_<xxxx> equivalents.
> > 
> > This patch remvoes the defines:
> > RS6000_BTM_FRES, RS6000_BTM_FRSQRTE, RS6000_BTM_FRSQRTES,
> > RS6000_BTM_POPCNTD, RS6000_BTM_CELL, RS6000_BTM_DFP,
> > RS6000_BTM_HARD_FLOAT, RS6000_BTM_LDBL128, RS6000_BTM_64BIT,
> > RS6000_BTM_POWERPC64, RS6000_BTM_FLOAT128, RS6000_BTM_FLOAT128_HW
> > RS6000_BTM_MMA, RS6000_BTM_P10.
> > 
> > I note that the BTM -> OPTION_MASK mappings are not always 1-to-1.
> > in particular the BTM_FRES and BTM_FRSQRTE values were both mapped
> > to
> > OPTION_MASK_PPC_GFXOPT, while the BTM_FRE and BTM_FRSQRTES both
> > mapped
> > to OPTION_MASK_POPCNTB.  In total I spent quite a bit of time
> > double-checking these since it looked like copy/paste errors.  I
> > split
> > some of these changes out into a subsequent patch to limit the
> > amount
> > of potential confusion in any particular patch.
> > 
> > gcc/
> > 	* config/rs6000/rs6000-c.cc: Update comments.
> > 	* config/rs6000/rs6000.cc (RS6000_BTM_FRES, RS6000_BTM_FRSQRTE,
> > 	RS6000_BTM_FRSQRTES, RS6000_BTM_POPCNTD, RS6000_BTM_CELL,
> > 	RS6000_BTM_64BIT, RS6000_BTM_POWERPC64, RS6000_BTM_DFP,
> > 	RS6000_BTM_HARD_FLOAT,RS6000_BTM_LDBL128, RS6000_BTM_FLOAT128,
> > 	RS6000_BTM_FLOAT128_HW, RS6000_BTM_MMA, RS6000_BTM_P10):
> > Replace
> > 	with OPTION_MASK_PPC_GFXOPT, OPTION_MASK_PPC_GFXOPT,
> > 	OPTION_MASK_POPCNTB, OPTION_MASK_POPCNTD,
> > 	OPTION_MASK_FPRND, MASK_64BIT, MASK_POWERPC64,
> > 	OPTION_MASK_DFP, OPTION_MASK_SOFT_FLOAT, OPTION_MASK_MULTIPLE,
> > 	OPTION_MASK_FLOAT128_KEYWORD, OPTION_MASK_FLOAT128_HW,
> > 	OPTION_MASK_MMA, OPTION_MASK_POWER10.
> > 	* config/rs6000/rs6000.h (RS6000_BTM_FRES, RS6000_BTM_FRSQRTE,
> > 	RS6000_BTM_FRSQRTES, RS6000_BTM_POPCNTD, RS6000_BTM_CELL,
> > 	RS6000_BTM_DFP, RS6000_BTM_HARD_FLOAT, RS6000_BTM_LDBL128,
> > 	RS6000_BTM_64BIT, RS6000_BTM_POWERPC64, RS6000_BTM_FLOAT128,
> > 	RS6000_BTM_FLOAT128_HW, RS6000_BTM_MMA, RS6000_BTM_P10):
> > Delete.
> > 
> > diff --git a/gcc/config/rs6000/rs6000-c.cc
> > b/gcc/config/rs6000/rs6000-c.cc
> > index 9c8cbd7a66e4..4c99afc761ae 100644
> > --- a/gcc/config/rs6000/rs6000-c.cc
> > +++ b/gcc/config/rs6000/rs6000-c.cc
> > @@ -594,13 +594,13 @@ rs6000_target_modify_macros (bool define_p,
> > HOST_WIDE_INT flags,
> >       via the target attribute/pragma.  */
> >    if ((flags & OPTION_MASK_FLOAT128_HW) != 0)
> >      rs6000_define_or_undefine_macro (define_p,
> > "__FLOAT128_HARDWARE__");
> >  
> >    /* options from the builtin masks.  */
> > -  /* Note that RS6000_BTM_CELL is enabled only if (rs6000_cpu ==
> > -     PROCESSOR_CELL) (e.g. -mcpu=cell).  */
> > -  if ((bu_mask & RS6000_BTM_CELL) != 0)
> > +  /* Note that OPTION_MASK_FPRND is enabled only if
> > +     (rs6000_cpu == PROCESSOR_CELL) (e.g. -mcpu=cell).  */
> > +  if ((bu_mask & OPTION_MASK_FPRND) != 0)
> >      rs6000_define_or_undefine_macro (define_p, "__PPU__");
> >  
> 
> ... here.  In function rs6000_target_modify_macros, bu_mask is used
> by
> two places, the beginning debug outputting and the above
> OPTION_MASK_FPRND
> check.  I wonder if we can get rid of bu_mask and just use sth. like:
> 
> (rs6000_cpu == PROCESSOR_CELL) && (flags & OPTION_MASK_FPRND)
> 

Agreed.

> // the others are using "flags &", it's passed by rs6000_isa_flags,
> // should be the same as just using OPTION_MASK_FPRND.
> 
> If we drop bu_mask in function rs6000_target_modify_macros, function

> rs6000_builtin_mask_calculate will have only one use place in
> function
> rs6000_option_override_internal.  IMHO this function
> rs6000_builtin_mask_calculate also becomes stale after built-in
> function
> rewriting and needs some updates with new bif framework later.

The DEBUG output using the builtin_mask still appeared to have some
potential value, but I can make a point to investigate that further.

I do have in my queue to try to resolve PR 101865, that is the bug with
ARCH_PWR8.  I got into this OPTION_MASK side-quest as part of the
investigation into that bug.   I can make a point to investigate and
clean up the bu_mask usage as part of that series.

Thanks
-Will

> 
> BR,
> Kewen