[Bug target/99197] New: Built-ins for packing/unpacking __ibm128 not documented

[Bug target/99197] New: Built-ins for packing/unpacking __ibm128 not documented

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99197

            Bug ID: 99197
           Summary: Built-ins for packing/unpacking __ibm128 not
                    documented
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Keywords: documentation
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: redi at gcc dot gnu.org
  Target Milestone: ---
            Target: powerpc*-*-*

https://gcc.gnu.org/onlinedocs/gcc/Basic-PowerPC-Built-in-Functions-Available-on-all-Configurations.html
has the prototypes:

double __builtin_unpack_ibm128 (__ibm128, int);
__ibm128 __builtin_pack_ibm128 (double, double);

But they are undocumented.

The simplest fix might be to just point to the next section of the docs and say
they behave the same as the corresponding __builtin_xxx_longdouble built-ins.

[Bug target/99197] Built-ins for packing/unpacking __ibm128 not documented

[meissner at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99197

Michael Meissner <meissner at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |meissner at gcc dot gnu.org
         Resolution|---                         |FIXED
             Status|UNCONFIRMED                 |RESOLVED

--- Comment #1 from Michael Meissner <meissner at gcc dot gnu.org> ---
These functions have been documented since June 2018.  The file extend.texi
contains:

The @code{__builtin_unpack_ibm128} function takes a @code{__ibm128}
argument and a compile time constant of 0 or 1.  If the constant is 0,
the first @code{double} within the @code{__ibm128} is returned,
otherwise the second @code{double} is returned.

The @code{__builtin_pack_ibm128} function takes two @code{double}
arguments and returns a @code{__ibm128} value that combines the two
arguments.

[Bug target/99197] Built-ins for packing/unpacking __ibm128 not documented

[linkw at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99197

Kewen Lin <linkw at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |linkw at gcc dot gnu.org

--- Comment #2 from Kewen Lin <linkw at gcc dot gnu.org> ---
Not sure if the documents could be taken inconsistent.

In the link
https://gcc.gnu.org/onlinedocs/gcc/Basic-PowerPC-Built-in-Functions-Available-on-ISA-2_002e05.html,
we have

"The basic built-in functions described in this section are available on the
PowerPC family of processors starting with ISA 2.05 or later."

The bifs __builtin_{un,}pack_{ibm128,longdouble} are listed on this page.

And the page Jonathan provided says

"The following built-in functions are also available on all PowerPC
processors:"

So the ones on this page presumably are typos?