RE: [PATCH] machine_mode type size: Extend enum size from 8-bit to 16-bit

["Li, Pan2" <pan2.li@intel.com>]

return !dv || (int) GET_CODE ((rtx) dv) != (int) VALUE; } is able to fix this ICE after mode bits change. I will re-trigger the memory allocate bytes test with below changes for X86.

rtx_def code 16 => 8 bits.
rtx_def mode 8 => 16 bits.
tree_base code unchanged.

Pan

-----Original Message-----
From: Li, Pan2 
Sent: Monday, May 8, 2023 2:42 PM
To: Richard Biener <rguenther@suse.de>; Jeff Law <jeffreyalaw@gmail.com>
Cc: Kito Cheng <kito.cheng@gmail.com>; juzhe.zhong@rivai.ai; richard.sandiford <richard.sandiford@arm.com>; gcc-patches <gcc-patches@gcc.gnu.org>; palmer <palmer@dabbelt.com>; jakub <jakub@redhat.com>
Subject: RE: [PATCH] machine_mode type size: Extend enum size from 8-bit to 16-bit

Oops. Actually I am patching a version as you mentioned like storage allocation. Thank you Richard, will try your suggestion and keep you posted.

Pan

-----Original Message-----
From: Richard Biener <rguenther@suse.de>
Sent: Monday, May 8, 2023 2:30 PM
To: Jeff Law <jeffreyalaw@gmail.com>
Cc: Li, Pan2 <pan2.li@intel.com>; Kito Cheng <kito.cheng@gmail.com>; juzhe.zhong@rivai.ai; richard.sandiford <richard.sandiford@arm.com>; gcc-patches <gcc-patches@gcc.gnu.org>; palmer <palmer@dabbelt.com>; jakub <jakub@redhat.com>
Subject: Re: [PATCH] machine_mode type size: Extend enum size from 8-bit to 16-bit

On Sun, 7 May 2023, Jeff Law wrote:

> 
> 
> On 5/6/23 19:55, Li, Pan2 wrote:
> > It looks like we cannot simply swap the code and mode in rtx_def, 
> > the code may have to be the same bits as the tree_code in tree_base.
> > Or we will meet ICE like below.
> > 
> > rtx_def code 16 => 8 bits.
> > rtx_def mode 8 => 16 bits.
> > 
> > static inline decl_or_value
> > dv_from_value (rtx value)
> > {
> >    decl_or_value dv;
> >    dv = value;
> >    gcc_checking_assert (dv_is_value_p (dv));  <=  ICE
> >    return dv;
> Ugh.  We really just need to fix this code.  It assumes particular 
> structure layouts and that's just wrong/dumb.

Well, it's a neat trick ... we just need to adjust it to

static inline bool
dv_is_decl_p (decl_or_value dv)
{
  return !dv || (int) GET_CODE ((rtx) dv) != (int) VALUE; }  

I think (and hope for the 'decl' case the bits inspected are never 'VALUE').  Of course the above stinks from a TBAA perspective ...

Any "real" fix would require allocating storage for a discriminator and thus hurt the resource constrained var-tracking a lot.

Richard.