On Wed, Jan 27, 2021 at 09:11:49PM -0600, Segher Boessenkool wrote: > On Tue, Jan 26, 2021 at 06:43:06PM -0500, Michael Meissner wrote: > > I posted this patch on January 14th, 2021: > > https://gcc.gnu.org/pipermail/gcc-patches/2021-January/563498.html > > > > | Date: Thu, 14 Jan 2021 12:09:36 -0500 > > | Subject: [PATCH] PowerPC: Add float128/Decimal conversions. > > | Message-ID: <20210114170936.ga3...@ibm-toto.the-meissners.org> > > > > You had a question about what changed, and I replied: > > > > | In your last message, you said that it was unacceptable that the > > conversion > > | fails if the user uses an old GLIBC. So I rewrote the code using weak > > | references. If the user has at least GLIBC 2.32, it will use the IEEE > > 128-bit > > | string support in the library. > > | > > | If an older GLIBC is used, I then use the IBM 128-bit format as an > > intermediate > > | value. Obviously there are cases where IEEE 128-bit can hold values that > > IBM > > | 128-bit can't (mostly due to the increased exponent range in IEEE > > 128-bit), but > > | it at least does the conversion for the numbers in the common range. > > | > > | In doing this transformation, I needed to do minor edits to the main > > decimal > > | to/from binary conversion functions to allow the KF functions to be > > declared. > > | Previously, I used preprocessor magic to rename the functions. > > > > This is the second most important patch in the IEEE 128-bit work. What do I > > need to do to be able to commit the patch? > > The whole thread is at > https://patchwork.ozlabs.org/project/gcc/patch/20201120000524.ga...@ibm-toto.the-meissners.org/ > . > > I approved *that* version of the patch.
Yes you approved the built-in renaming patch and I checked in the patch that you approved (rather than the modifications that I submitted). However, this is about the second patch (that provides conversions between _Float128 and Decimal), which as far as I can tell was not approved. That is what this particular question is about. You did not like the previous _Float128 <-> Decimal conversion patch because it was tied into having a minimum GLIBC version. So, I rewrote the whole patch so that it will work with older GLIBC's. If you have a newer GLIBC (detected at runtime via a weak reference), it uses the support functions in the new GLIBC to do the conversion. I had a cut+paste error in the original patch that I resubmitted, and I resubmitted with the changed line. If you have an older GLIBC and want to convert _Float128 to one of the Decimal types, it will convert the _Float128 to __ibm128 and then convert that to Decimal. Similarly if you have one of the Decimal types, and want to convert to _Float128, it will first convert the Decimal type to __ibm128, and then convert __ibm128 to _Float128. So what do I do? Can I check in this patch or do I need to do further modifications. -- Michael Meissner, IBM IBM, M/S 2506R, 550 King Street, Littleton, MA 01460-6245, USA email: meiss...@linux.ibm.com, phone: +1 (978) 899-4797
