Again: I am not sure how I can best help here, or even if I can.
I am happy to run tests, so just ask.
I am going to go back working on converting the larger UAT test suite.
> -----Original Message-----
> From: Robert Dubner <rdub...@symas.com>
> Sent: Friday, March 21, 2025 15:33
> To: Richard Biener <rguent...@suse.de>; Jakub Jelinek <ja...@redhat.com>
> Cc: gcc-patches@gcc.gnu.org
> Subject: RE: [PATCH] change cbl_field_data_t::etc_t::value from
_Float128
> to tree
>
>
>
> > -----Original Message-----
> > From: Richard Biener <rguent...@suse.de>
> > Sent: Friday, March 21, 2025 15:25
> > To: Jakub Jelinek <ja...@redhat.com>
> > Cc: Robert Dubner <rdub...@symas.com>; gcc-patches@gcc.gnu.org
> > Subject: Re: [PATCH] change cbl_field_data_t::etc_t::value from
> _Float128
> > to tree
> >
> > On Fri, 21 Mar 2025, Jakub Jelinek wrote:
> >
> > > On Fri, Mar 21, 2025 at 01:47:05PM -0500, Robert Dubner wrote:
> > > > > -----Original Message-----
> > > > > From: Robert Dubner <rdub...@symas.com>
> > > > > Sent: Friday, March 21, 2025 14:23
> > > > > To: Richard Biener <rguent...@suse.de>
> > > > > Cc: gcc-patches@gcc.gnu.org; Jakub Jelinek <ja...@redhat.com>
> > > > > Subject: RE: [PATCH] change cbl_field_data_t::etc_t::value from
> > > > _Float128
> > > > > to tree
> > > > >
> > > > > Crossed in the mail.
> > > > >
> > > > > I applied your fixes below.
> > > > >
> > > > > The output of the one-liner program is now 1.2345678E+07, as
> > expected.
> > > > >
> > > > > The .00 instead of .01 problem still exists; source code coming
> > soon.
> > > >
> > > > This program
> > > >
> > > > IDENTIFICATION DIVISION.
> > > > PROGRAM-ID. numeds.
> > > > DATA DIVISION.
> > > > WORKING-STORAGE SECTION.
> > > > 01 VARP9 PIC P9 VALUE 0.01.
> > > > PROCEDURE DIVISION.
> > > > DISPLAY "VARP9 should be .01"
> > > > DISPLAY "VARP9 is " VARP9.
> > > > END PROGRAM numeds.
> > > >
> > > > generates
> > > >
> > > > VARP9 should be .01
> > > > VARP9 is .00
> > > >
> > > > As usual, it's COBOL, so it comes with a lecture:
> > > >
> > > > The variable
> > > >
> > > > 01 VARP9 PIC P9 VALUE 0.01.
> > > >
> > > > means that it is a NUMERIC DISPLAY variable, which is represented
in
> > > > memory as ASCII digits. There is but one '9' in the PICTURE, so
it
> is
> > a
> > > > one-digit number. The prefix 'P', in the "P9", means that the
> actual
> > > > value of the variable is scaled by 0.01 So, the value 0.01 is
> > represented
> > > > in memory by a single "1".
> > > >
> > > > If it were "PIC 9PPP", then 1,000 would be represented in memory
as
> a
> > > > single "1".
> > >
> > > The following incremental patch should fix that (but otherwise
> > untested).
> > >
> > > --- gcc/cobol/parse.y.jj 2025-03-21 17:49:43.571440176 +0100
> > > +++ gcc/cobol/parse.y 2025-03-21 20:15:24.852414777 +0100
> > > @@ -4331,7 +4331,8 @@ value_clause: VALUE all LITERAL[lit] {
> > > cbl_field_t *field = current_field();
> > > auto orig_str = original_number();
> > > REAL_VALUE_TYPE orig_val;
> > > - real_from_string (&orig_val, orig_str);
> > > + real_from_string3 (&orig_val, orig_str,
> > > + TYPE_MODE (float128_type_node));
> > > char *initial = NULL;
> > >
> > > if( real_identical (&orig_val, &$value) ) {
> > > @@ -6922,7 +6923,8 @@ cce_expr: cce_factor
> > > cce_factor: NUMSTR {
> > > /* ??? real_from_string does not allow arbitrary
> > radix. */
> > > // $$ = numstr2i($1.string, $1.radix);
> > > - real_from_string (&$$, $1.string);
> > > + real_from_string3 (&$$, $1.string,
> > > + TYPE_MODE (float128_type_node));
> > > }
> > > ;
> > >
> > >
> > > The old code was just using _Float128 which has the IEEE quad
> precision,
> > > but REAL_VALUE_TYPE in GCC actually has larger internal precision
than
> > that,
> > > so if it isn't rounded to the IEEE quad precision first and builds
> > REAL_CST,
> > > it isn't the expected 0.0100000000000000000000000000000000002 but
> > > 0.009999999999...
> >
> > Hmm, but I see that digits_from_float128 from
> >
> > (gdb) p debug (value)
> > 1.0e+0
> >
> > produces via real_to_integer zero:
> >
> > (gdb) s
> > real_to_integer (r=0x7fffffff69a0, fail=0x7fffffff685f, precision=128)
> > at ../../src/gcc/gcc/real.cc:1483
> > (gdb) p debug (*r)
> > 1.0e+0
> > (gdb) n
> > 1485 switch (r->cl)
> > (gdb)
> > 1502 if (r->decimal)
> > (gdb)
> > 1505 exp = REAL_EXP (r);
> > (gdb)
> > 1506 if (exp <= 0)
> > (gdb)
> > 1507 goto underflow;
> > (gdb)
> > 1489 return wi::zero (precision);
> >
> > we've come from initial_from_float128 which does
> >
> > REAL_VALUE_TYPE pow10
> > = real_powi10 (field->data.digits + field->data.rdigits);
> > real_arithmetic (&value, MULT_EXPR, &value, &pow10);
> >
> > which produces the 1.0e+0 - do I need to process this to be "normal"?
> >
> > Richard.
>
> I am not fully following what you are discussing here.
>
> I can say that applying Jakub's incremental patch did fix the .01
example,
> but it broke a number of others.
>
>
