Re: [PATCH] Add inchash support for vrange.

[Jakub Jelinek <jakub@redhat.com>]

On Tue, Apr 18, 2023 at 11:06:38AM +0200, Aldy Hernandez via Gcc-patches wrote:
> This patch provides inchash support for vrange.  It is along the lines
> of the streaming support I just posted and will be used for IPA
> hashing of ranges.
> 
> Thoughts?
> 
> gcc/ChangeLog:
> 
> 	* inchash.cc (hash::add_real_value): New.
> 	* inchash.h (class hash): Add add_real_value.
> 	* value-range.cc (add_vrange): New.
> 	* value-range.h (inchash::add_vrange): New.
> ---
>  gcc/inchash.cc     | 20 +++++++++++++++++++
>  gcc/inchash.h      |  2 ++
>  gcc/value-range.cc | 48 ++++++++++++++++++++++++++++++++++++++++++++++
>  gcc/value-range.h  |  6 ++++++
>  4 files changed, 76 insertions(+)
> 
> diff --git a/gcc/inchash.cc b/gcc/inchash.cc
> index a30662b97fe..914e3cc92cd 100644
> --- a/gcc/inchash.cc
> +++ b/gcc/inchash.cc
> @@ -24,3 +24,23 @@ along with GCC; see the file COPYING3.  If not see
>  #endif
>  #include "system.h"
>  #include "coretypes.h"
> +#include "real.h"
> +#include "inchash.h"
> +
> +namespace inchash
> +{
> +
> +/* This is here instead of inchash.h to keep us from having to put
> +   real.h in coretypes.h.  */
> +void
> +hash::add_real_value (const real_value &v)
> +{
> +  add_int (v.sign);
> +  add_int (v.uexp);
> +  for (unsigned i = 0; i < SIGSZ; ++i)
> +    add_hwi (v.sig[i]);
> +  /* Ignore the rest of the flags, as sign, exponent, and
> +     significant bits should be enough.  */

I don't think that's the case.
At least cl, decimal and signalling are essential flags as well.
Dunno about canonical.
How do you otherwise differentiate between Inf and +0.0 or (canonical)
qNaN or (canonical) sNaN?
They have the same sign, uexp and sig.

	Jakub