From: Joseph Myers <joseph@codesourcery.com>
To: Segher Boessenkool <segher@kernel.crashing.org>
Cc: Kewen.Lin <linkw@linux.ibm.com>,
GCC Patches <gcc-patches@gcc.gnu.org>,
Michael Meissner <meissner@linux.ibm.com>,
David Edelsohn <dje.gcc@gmail.com>,
Jakub Jelinek <jakub@redhat.com>,
Peter Bergner <bergner@linux.ibm.com>,
Richard Biener <richard.guenther@gmail.com>,
Richard Sandiford <richard.sandiford@arm.com>
Subject: Re: [RFC/PATCH] Remove the workaround for _Float128 precision [PR107299]
Date: Wed, 21 Dec 2022 21:40:24 +0000 [thread overview]
Message-ID: <a4f011e0-544c-c62-1cfc-e013d140728f@codesourcery.com> (raw)
In-Reply-To: <20221221212407.GU25951@gate.crashing.org>
On Wed, 21 Dec 2022, Segher Boessenkool wrote:
> > --- a/gcc/tree.cc
> > +++ b/gcc/tree.cc
> > @@ -9442,15 +9442,6 @@ build_common_tree_nodes (bool signed_char)
> > if (!targetm.floatn_mode (n, extended).exists (&mode))
> > continue;
> > int precision = GET_MODE_PRECISION (mode);
> > - /* Work around the rs6000 KFmode having precision 113 not
> > - 128. */
>
> It has precision 126 now fwiw.
>
> Joseph: what do you think about this patch? Is the workaround it
> removes still useful in any way, do we need to do that some other way if
> we remove this?
I think it's best for the TYPE_PRECISION, for any type with the binary128
format, to be 128 (not 126).
It's necessary that _Float128, _Float64x and long double all have the same
TYPE_PRECISION when they have the same (binary128) format, or at least
that TYPE_PRECISION for _Float128 >= that for long double >= that for
_Float64x, so that the rules in c_common_type apply properly.
How the TYPE_PRECISION compares to that of __ibm128, or of long double
when that's double-double, is less important.
--
Joseph S. Myers
joseph@codesourcery.com
next prev parent reply other threads:[~2022-12-21 21:40 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-21 9:02 Kewen.Lin
2022-12-21 21:24 ` Segher Boessenkool
2022-12-21 21:40 ` Joseph Myers [this message]
2022-12-21 22:45 ` Jakub Jelinek
2022-12-22 6:37 ` Kewen.Lin
2022-12-22 18:18 ` Segher Boessenkool
2022-12-22 19:48 ` Joseph Myers
2022-12-22 22:09 ` Segher Boessenkool
2023-01-03 23:27 ` Michael Meissner
2023-01-07 0:41 ` Michael Meissner
2023-01-10 3:21 ` Michael Meissner
2023-01-10 18:23 ` Jakub Jelinek
2023-01-11 20:26 ` Michael Meissner
2022-12-22 6:07 ` Kewen.Lin
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