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 <rguent...@suse.de>
Sent: Monday, May 8, 2023 2:30 PM
To: Jeff Law <jeffreya...@gmail.com>
Cc: Li, Pan2 <pan2...@intel.com>; Kito Cheng <kito.ch...@gmail.com>;
juzhe.zh...@rivai.ai; richard.sandiford <richard.sandif...@arm.com>;
gcc-patches <gcc-patches@gcc.gnu.org>; palmer <pal...@dabbelt.com>; jakub
<ja...@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.
