Re: [PATCH] frange: dump hex values when dumping FP numbers.

[Toon Moene <toon@moene.org>]

If it's not too cumbersome, I suggest dumping both.

In my neck-of-the-woods (meteorology) I have seen this done just to 
ensure that algorithms that are supposed to be bit-reproducable actually 
are - and that it can be checked visually.

Kind regards,
Toon.

On 9/22/22 18:49, Aldy Hernandez via Gcc-patches wrote:

> It has been suggested that if we start bumping numbers by an ULP when
> calculating open ranges (for example the numbers less than 3.0) that
> dumping these will become increasingly harder to read, and instead we
> should opt for the hex representation.  I still find the floating
> point representation easier to read for most numbers, but perhaps we
> could have both?
> 
> With this patch this is the representation for [15.0, 20.0]:
> 
>       [frange] float [1.5e+1 (0x0.fp+4), 2.0e+1 (0x0.ap+5)]
> 
> Would you find this useful, or should we stick to the hex
> representation only (or something altogether different)?
> 
> Tested on x86-64 Linux.
> 
> gcc/ChangeLog:
> 
> 	* value-range-pretty-print.cc (vrange_printer::print_real_value): New.
> 	(vrange_printer::visit): Call print_real_value.
> 	* value-range-pretty-print.h: New print_real_value.
> ---
>   gcc/value-range-pretty-print.cc | 16 ++++++++++++----
>   gcc/value-range-pretty-print.h  |  1 +
>   2 files changed, 13 insertions(+), 4 deletions(-)
> 
> diff --git a/gcc/value-range-pretty-print.cc b/gcc/value-range-pretty-print.cc
> index eb7442229ba..51be037c254 100644
> --- a/gcc/value-range-pretty-print.cc
> +++ b/gcc/value-range-pretty-print.cc
> @@ -117,6 +117,16 @@ vrange_printer::print_irange_bitmasks (const irange &r) const
>     pp_string (pp, buf);
>   }
>   
> +void
> +vrange_printer::print_real_value (tree type, const REAL_VALUE_TYPE &r) const
> +{
> +  char s[60];
> +  tree t = build_real (type, r);
> +  dump_generic_node (pp, t, 0, TDF_NONE, false);
> +  real_to_hexadecimal (s, &r, sizeof (s), 0, 1);
> +  pp_printf (pp, " (%s)", s);
> +}
> +
>   // Print an frange.
>   
>   void
> @@ -141,11 +151,9 @@ vrange_printer::visit (const frange &r) const
>     bool has_endpoints = !r.known_isnan ();
>     if (has_endpoints)
>       {
> -      dump_generic_node (pp,
> -			 build_real (type, r.lower_bound ()), 0, TDF_NONE, false);
> +      print_real_value (type, r.lower_bound ());
>         pp_string (pp, ", ");
> -      dump_generic_node (pp,
> -			 build_real (type, r.upper_bound ()), 0, TDF_NONE, false);
> +      print_real_value (type, r.upper_bound ());
>       }
>     pp_character (pp, ']');
>     print_frange_nan (r);
> diff --git a/gcc/value-range-pretty-print.h b/gcc/value-range-pretty-print.h
> index 20c26598fe7..a9ae5a7b4cc 100644
> --- a/gcc/value-range-pretty-print.h
> +++ b/gcc/value-range-pretty-print.h
> @@ -32,6 +32,7 @@ private:
>     void print_irange_bound (const wide_int &w, tree type) const;
>     void print_irange_bitmasks (const irange &) const;
>     void print_frange_nan (const frange &) const;
> +  void print_real_value (tree type, const REAL_VALUE_TYPE &r) const;
>   
>     pretty_printer *pp;
>   };

-- 
Toon Moene - e-mail: toon@moene.org - phone: +31 346 214290
Saturnushof 14, 3738 XG  Maartensdijk, The Netherlands