[Bug modula2/111956] Many powerpc platforms do _not_ have support for IEEE754 long double
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111956 --- Comment #12 from Gaius Mulley --- Many thanks for the feedback and testing - I'll rework the patch and post it to gcc-patches as suggested.
[Bug modula2/111956] Many powerpc platforms do _not_ have support for IEEE754 long double
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111956 Thomas Koenig changed: What|Removed |Added CC||tkoenig at gcc dot gnu.org --- Comment #11 from Thomas Koenig --- A remark - gfortran handles 128-bit reals on POWER as well, it might be a good idea to look into libgfortran's configure scripts.
[Bug modula2/111956] Many powerpc platforms do _not_ have support for IEEE754 long double
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111956 --- Comment #10 from Thomas Schwinge --- In addition to what Maciej said (..., and similarly, I don't have any proper knowledge about PowerPC details): (In reply to Gaius Mulley from comment #6) > Created attachment 56522 [details] > Proposed fix v5 Thanks for looking into this! > Here is the latest patch which [...] 96 > failures on gcc135. [...] With no special 'configure' flags, I'm seeing (presumably) those, too. I noticed in 'build-gcc/gcc/m2/config-make' (generated from 'gcc/m2/config-make.in'): # Does the target have -mabi=ieeelongdouble support in libm? (yes/no). HAVE_TARGET_LONG_DOUBLE_IEEE = @have_target_long_double_ieee@ ..., so missing 'AC_SUBST' or similar -- but is that actually unused? I further noticed the following delta when regenerating 'libgm2/configure': case "$target" in powerpc*-*-linux*) - LONG_DOUBLE_COMPAT_FLAGS="$LONG_DOUBLE_COMPAT_FLAGS -mno-gnu-attribute" # Check for IEEE128 support in libm: (In reply to Gaius Mulley from comment #8) > Here is the same patch as v5 but generated using git diff -w. Please don't include unrelated changes (here: whitespace cleanup); handle that separately (if you must). ;-)
[Bug modula2/111956] Many powerpc platforms do _not_ have support for IEEE754 long double
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111956 --- Comment #9 from Maciej W. Rozycki --- Hmm, the host check for `__frexpieee128' in gcc/ will surely not do what's intended: even if the host is `powerpc*-*-linux*', the target will often be something else and vice versa (libgm2's host is GCC's target). I think there is no way to verify target C library features in gcc/ at `configure' time, because at this point we may not yet have a target compiler. I haven't dealt with such a situation before, but AFAICS people have used GCC_GLIBC_VERSION_GTE_IFELSE to explicitly check for the glibc version required instead. There's a relevant case for TARGET_DEFAULT_LONG_DOUBLE_128 you can use as an example. I'm not sure if such a check is needed though, unless perhaps for sanity, as you only define TARGET_LIBM_PROVIDES_LONG_DOUBLE_IEEE128 if --with-long-double-format=ieee has been explicitly given. Also ISTM you can omit the target check for `powerpc64le-*-linux*' here keeping $with_long_double_format=ieee check only and get support for the relevant `powerpc64-*-linux*' targets too, as -with-long-double-format= will already have verified correct usage. Finally you may or may not have to check for $gcc_cv_target_ldbl128 equal to "yes" too, in case someone has used --without-long-double-128 (I'm not sure what the consequences would be, but it has caught my attention, so please double-check). Overall please refer to someone more familiar with POWER GCC targets as I can only comment based on what I can see in the scripts and my general experience. The best course of action might be submitting the patch to gcc-patches for review, cc-ing RS6000 port maintainers, as the most relevant people may not be reading this bug report.
[Bug modula2/111956] Many powerpc platforms do _not_ have support for IEEE754 long double
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111956 --- Comment #8 from Gaius Mulley --- Created attachment 56524 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=56524=edit Proposed fix v5 (git diff -w) Here is the same patch as v5 but generated using git diff -w.
[Bug modula2/111956] Many powerpc platforms do _not_ have support for IEEE754 long double
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111956 Gaius Mulley changed: What|Removed |Added Status|NEW |ASSIGNED --- Comment #7 from Gaius Mulley --- Adding another patch using git diff -w to reduce patch clutter for review.
[Bug modula2/111956] Many powerpc platforms do _not_ have support for IEEE754 long double
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111956 Gaius Mulley changed: What|Removed |Added Attachment #56508|0 |1 is obsolete|| --- Comment #6 from Gaius Mulley --- Created attachment 56522 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=56522=edit Proposed fix v5 Many thanks for the hint about the __frexpieee128 libm test. Here is the latest patch which passes all tests on gcc120 and has 96 failures on gcc135. It was configured with --with-long-double-format=ieee on gcc120. It has separate checks (or switch) for host and target long double 128 support.
[Bug modula2/111956] Many powerpc platforms do _not_ have support for IEEE754 long double
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111956 --- Comment #5 from Maciej W. Rozycki --- Hmm, this seems awkward to me. It won't work AFAICT with the usual native bootstrap environment, where you just run: $ /path/to/configure && make bootstrap and it won't work where you have an old version of glibc installed and build with: $ /path/to/configure --with-cpu=power10 && make bootstrap either. Shouldn't this just use the same check that libstdc++ does? See the piece starting with: # Check for IEEE128 support in libm. in libstdc++-v3/configure.ac. Maybe you just need to check for the presence of `__frexpieee128' and ignore the rest, as you don't seem to be willing to provide support for the IBM long double format in libgm2, or do you?
[Bug modula2/111956] Many powerpc platforms do _not_ have support for IEEE754 long double
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111956 Gaius Mulley changed: What|Removed |Added CC||gaius at gcc dot gnu.org --- Comment #4 from Gaius Mulley --- Created attachment 56508 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=56508=edit Proposed fix Here is a proposed patch which detects whether the target_cpu is power10 and target is ppc64le. I've seen it build successfully on gcc135 (without bootstrap) and bootstrap on gcc120 (I'm currently running a bootstrap on gcc135). I'm unsure whether these libgm2/configure.ac and gcc/m2/configure.ac tests are sufficient - and suspect more combinations should be checked (ie the shell case statements might need expanding).
[Bug modula2/111956] Many powerpc platforms do _not_ have support for IEEE754 long double
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111956 --- Comment #3 from Eric Gallager --- (In reply to Thomas Schwinge from comment #2) > While you (Gaius) here report test failure, similar to what Maciej had > reported in PR112091 "rs6000: redefinition of 'constexpr long double > std::abs(long double)', while building libgm2", I can't even build libgm2 > anymore. > > Similar had reported Eric (CCed here) on GCC IRC, 2023-10-20: > > ok now this is an error I haven't seen before > > /home/egallager/gcc/.cfarm135_build.build/powerpc64le-unknown-linux-gnu/ > libstdc++-v3/include/bits/std_abs.h:137:3: error: redefinition of 'constexpr > long double std::abs(long double)' > seen on cfarm135 > I think I remember something about __float128 being weird > on certain powerpc systems? Is there a configure flag that affects it? > I'll open a bug about it... > although actually wait... I'm not quite sure the > component, though... it's an error from a libstdc++ header, but it shows up > while building KeyBoardLEDs.lo for libm2cor in libgm2, but only for a > specific target... Ah, thanks for the cc! I'd meant to look further into this, but got distracted by other things...
[Bug modula2/111956] Many powerpc platforms do _not_ have support for IEEE754 long double
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111956 Thomas Schwinge changed: What|Removed |Added Keywords||build CC||egallager at gcc dot gnu.org, ||tschwinge at gcc dot gnu.org Last reconfirmed||2023-10-31 Ever confirmed|0 |1 Status|UNCONFIRMED |NEW --- Comment #2 from Thomas Schwinge --- While you (Gaius) here report test failure, similar to what Maciej had reported in PR112091 "rs6000: redefinition of 'constexpr long double std::abs(long double)', while building libgm2", I can't even build libgm2 anymore. Similar had reported Eric (CCed here) on GCC IRC, 2023-10-20: ok now this is an error I haven't seen before /home/egallager/gcc/.cfarm135_build.build/powerpc64le-unknown-linux-gnu/libstdc++-v3/include/bits/std_abs.h:137:3: error: redefinition of 'constexpr long double std::abs(long double)' seen on cfarm135 I think I remember something about __float128 being weird on certain powerpc systems? Is there a configure flag that affects it? I'll open a bug about it... although actually wait... I'm not quite sure the component, though... it's an error from a libstdc++ header, but it shows up while building KeyBoardLEDs.lo for libm2cor in libgm2, but only for a specific target... For example, I've got on powerpc64le-unknown-linux-gnu on indeed old Ubuntu 14.04 "trusty": +#define M2C_LONGREAL_FLOAT128 1 +#define M2C_LONGREAL_PPC64LE 1 ..., and this fails to build as follows: libtool: compile: [...]/build-gcc/./gcc/xg++ -B[...]/build-gcc/./gcc/ -nostdinc++ -nostdinc++ -I[...]/build-gcc/powerpc64le-unknown-linux-gnu/libstdc++-v3/include/powerpc64le-unknown-linux-gnu -I[...]/build-gcc/powerpc64le-unknown-linux-gnu/libstdc++-v3/include -I[...]/source-gcc/libstdc++-v3/libsupc++ -I[...]/source-gcc/libstdc++-v3/include/backward -I[...]/source-gcc/libstdc++-v3/testsuite/util -L[...]/build-gcc/powerpc64le-unknown-linux-gnu/libstdc++-v3/src -L[...]/build-gcc/powerpc64le-unknown-linux-gnu/libstdc++-v3/src/.libs -L[...]/build-gcc/powerpc64le-unknown-linux-gnu/libstdc++-v3/libsupc++/.libs -B/powerpc64le-unknown-linux-gnu/bin/ -B/powerpc64le-unknown-linux-gnu/lib/ -isystem /powerpc64le-unknown-linux-gnu/include -isystem /powerpc64le-unknown-linux-gnu/sys-include -c -I[...]/source-gcc/libgm2/libm2cor -g -O2 -D_GNU_SOURCE -g -O2 -I. -I.. -I[...]/source-gcc/gcc/m2/gm2-libs -I[...]/source-gcc/gcc/m2/gm2-libs-iso -DBUILD_GM2_LIBS -I[...]/source-gcc/libgm2/libm2cor/../ -I[...]/source-gcc/libgm2/libm2cor/../libm2iso -mabi=ieeelongdouble [...]/source-gcc/libgm2/libm2cor/KeyBoardLEDs.cc -fPIC -DPIC -o .libs/KeyBoardLEDs.o cc1plus: warning: Using IEEE extended precision ‘long double’ [-Wpsabi] In file included from [...]/build-gcc/powerpc64le-unknown-linux-gnu/libstdc++-v3/include/cstdlib:81, from [...]/build-gcc/powerpc64le-unknown-linux-gnu/libstdc++-v3/include/stdlib.h:36, from [...]/source-gcc/libgm2/libm2cor/KeyBoardLEDs.cc:43: [...]/build-gcc/powerpc64le-unknown-linux-gnu/libstdc++-v3/include/bits/std_abs.h:137:3: error: redefinition of ‘constexpr long double std::abs(long double)’ 137 | abs(__float128 __x) | ^~~ [...]/build-gcc/powerpc64le-unknown-linux-gnu/libstdc++-v3/include/bits/std_abs.h:79:3: note: ‘constexpr long double std::abs(long double)’ previously defined here 79 | abs(long double __x) | ^~~ make[5]: *** [KeyBoardLEDs.lo] Error 1 [...] libtool: compile: [...]/build-gcc/./gcc/xg++ -B[...]/build-gcc/./gcc/ -nostdinc++ -nostdinc++ -I[...]/build-gcc/powerpc64le-unknown-linux-gnu/libstdc++-v3/include/powerpc64le-unknown-linux-gnu -I[...]/build-gcc/powerpc64le-unknown-linux-gnu/libstdc++-v3/include -I[...]/source-gcc/libstdc++-v3/libsupc++ -I[...]/source-gcc/libstdc++-v3/include/backward -I[...]/source-gcc/libstdc++-v3/testsuite/util -L[...]/build-gcc/powerpc64le-unknown-linux-gnu/libstdc++-v3/src -L[...]/build-gcc/powerpc64le-unknown-linux-gnu/libstdc++-v3/src/.libs -L[...]/build-gcc/powerpc64le-unknown-linux-gnu/libstdc++-v3/libsupc++/.libs -B/powerpc64le-unknown-linux-gnu/bin/ -B/powerpc64le-unknown-linux-gnu/lib/ -isystem /powerpc64le-unknown-linux-gnu/include -isystem /powerpc64le-unknown-linux-gnu/sys-include -c -I[...]/source-gcc/libgm2/libm2pim -g -O2 -D_GNU_SOURCE -g -O2 -I. -I.. -I[...]/source-gcc/gcc/m2/gm2-libs -I[...]/source-gcc/gcc/m2/gm2-libs-iso -DBUILD_GM2_LIBS -I[...]/source-gcc/libgm2/libm2pim/../ -I[...]/source-gcc/libgm2/libm2pim/../libm2iso -mabi=ieeelongdouble [...]/source-gcc/libgm2/libm2pim/wrapc.cc -fPIC -DPIC -o .libs/wrapc.o cc1plus: warning: Using IEEE extended precision ‘long double’ [-Wpsabi]
[Bug modula2/111956] Many powerpc platforms do _not_ have support for IEEE754 long double
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111956 Andrew Pinski changed: What|Removed |Added CC||macro at orcam dot me.uk --- Comment #1 from Andrew Pinski --- *** Bug 112091 has been marked as a duplicate of this bug. ***
