Re: [PATCH 2/4] fortran: Teach get_real_kind_from_node for Power 128 fp modes [PR112993]g
On Thu, May 09, 2024 at 01:37:32PM +0800, Kewen.Lin wrote: > > > > > That said, Fortran has the concept of model numbers, which > > are set in arith.c. Does this change give the expected > > value for ibm128? For example, with "REAL(16) X", one > > has "DIGITS(X) = 113", which is the precision on the > > of the underlying IEEE754 binary128 type. > > > > With some testings locally, I noticed that currently DIGITS has > been already correct even without this change. For "REAL(16) X", > with -mabi=ibmlongdouble it's long double with ibm128 format and > its DIGITS(X) is 106, while with -mabi=ieeelongdouble it's long > double with ieee128 format and its DIGITS(X) is 113. > That's good. I'll take a look later this weekend at arith.c. There are few others to consider: precision(x), minexponent(x), maxexponent(x), huge(x), and tiny(x). -- Steve
Re: [PATCH 2/4] fortran: Teach get_real_kind_from_node for Power 128 fp modes [PR112993]g
Hi, on 2024/5/9 06:01, Steve Kargl wrote: > On Wed, May 08, 2024 at 01:27:53PM +0800, Kewen.Lin wrote: >> >> Previously effective target fortran_real_c_float128 never >> passes on Power regardless of the default 128 long double >> is ibmlongdouble or ieeelongdouble. It's due to that TF >> mode is always used for kind 16 real, which has precision >> 127, while the node float128_type_node for c_float128 has >> 128 type precision, get_real_kind_from_node can't find a >> matching as it only checks gfc_real_kinds[i].mode_precision >> and type precision. >> >> With changing TFmode/IFmode/KFmode to have the same mode >> precision 128, now fortran_real_c_float12 can pass with >> ieeelongdouble enabled by default and test cases guarded >> with it get tested accordingly. But with ibmlongdouble >> enabled by default, since TFmode has precision 128 which >> is the same as type precision 128 of float128_type_node, >> get_real_kind_from_node considers kind for TFmode matches >> float128_type_node, but it's wrong as at this time point >> TFmode is with ibm extended format. So this patch is to >> teach get_real_kind_from_node to check one more field which >> can be differentiable from the underlying real format, it >> can avoid the unexpected matching when there more than one >> modes have the same precision. >> >> Bootstrapped and regress-tested on: >> - powerpc64-linux-gnu P8/P9 (with ibm128 by default) >> - powerpc64le-linux-gnu P9/P10 (with ibm128 by default) >> - powerpc64le-linux-gnu P9 (with ieee128 by default) >> >> BR, >> Kewen >> - >> PR target/112993 >> > OK from the fortran point of view. > Thanks. > > First, I have no issue with Mikael's OK for committing the > patch. Thanks to both! > > That said, Fortran has the concept of model numbers, which > are set in arith.c. Does this change give the expected > value for ibm128? For example, with "REAL(16) X", one > has "DIGITS(X) = 113", which is the precision on the > of the underlying IEEE754 binary128 type. > With some testings locally, I noticed that currently DIGITS has been already correct even without this change. For "REAL(16) X", with -mabi=ibmlongdouble it's long double with ibm128 format and its DIGITS(X) is 106, while with -mabi=ieeelongdouble it's long double with ieee128 format and its DIGITS(X) is 113. BR, Kewen
Re: [PATCH 2/4] fortran: Teach get_real_kind_from_node for Power 128 fp modes [PR112993]g
On Wed, May 08, 2024 at 01:27:53PM +0800, Kewen.Lin wrote: > > Previously effective target fortran_real_c_float128 never > passes on Power regardless of the default 128 long double > is ibmlongdouble or ieeelongdouble. It's due to that TF > mode is always used for kind 16 real, which has precision > 127, while the node float128_type_node for c_float128 has > 128 type precision, get_real_kind_from_node can't find a > matching as it only checks gfc_real_kinds[i].mode_precision > and type precision. > > With changing TFmode/IFmode/KFmode to have the same mode > precision 128, now fortran_real_c_float12 can pass with > ieeelongdouble enabled by default and test cases guarded > with it get tested accordingly. But with ibmlongdouble > enabled by default, since TFmode has precision 128 which > is the same as type precision 128 of float128_type_node, > get_real_kind_from_node considers kind for TFmode matches > float128_type_node, but it's wrong as at this time point > TFmode is with ibm extended format. So this patch is to > teach get_real_kind_from_node to check one more field which > can be differentiable from the underlying real format, it > can avoid the unexpected matching when there more than one > modes have the same precision. > > Bootstrapped and regress-tested on: > - powerpc64-linux-gnu P8/P9 (with ibm128 by default) > - powerpc64le-linux-gnu P9/P10 (with ibm128 by default) > - powerpc64le-linux-gnu P9 (with ieee128 by default) > > BR, > Kewen > - > PR target/112993 > First, I have no issue with Mikael's OK for committing the patch. That said, Fortran has the concept of model numbers, which are set in arith.c. Does this change give the expected value for ibm128? For example, with "REAL(16) X", one has "DIGITS(X) = 113", which is the precision on the of the underlying IEEE754 binary128 type. -- Steve
