| Message ID | 20180312190224.19137-1-tuliom@linux.vnet.ibm.com |
|---|---|
| State | New |
| Headers | show |
| Series | [PATCHv2] PR libstdc++/84654 Do not use __float128 if it is disabled by the compiler | expand |
Ping? Tulio Magno Quites Machado Filho <tuliom@linux.vnet.ibm.com> writes: > Changes since v1: > - Completely rewrite of the patch to set ENABLE_FLOAT128 at libstdc++ > build time and undef _GLIBCXX_USE_FLOAT128 when building user code. > > --- 8< --- > > In order to use __float128 in C++ it's necessary to check if the > compiler enabled its support too when building user code. > This patch changes the behavior at libstdc++ build by setting > ENABLE_FLOAT128, which is used to set the value of the exported macro > _GLIBCXX_USE_FLOAT128. > > 2018-03-12 Tulio Magno Quites Machado Filho <tuliom@linux.vnet.ibm.com> > > PR libstdc++/84654 > * acinclude.m4: Set ENABLE_FLOAT128 instead of _GLIBCXX_USE_FLOAT128. > * config.h.in: Remove references to _GLIBCXX_USE_FLOAT128. > * configure: Regenerate. > * include/Makefile.am: Replace the value of _GLIBCXX_USE_FLOAT128 > based on ENABLE_FLOAT128. > * include/Makefile.in: Regenerate. > * include/bits/c++config: Define _GLIBCXX_USE_FLOAT128. > [!defined(__FLOAT128__) && !defined(__SIZEOF_FLOAT128__)]: Undefine > _GLIBCXX_USE_FLOAT128.
On 12/03/18 16:02 -0300, Tulio Magno Quites Machado Filho wrote: >Changes since v1: > - Completely rewrite of the patch to set ENABLE_FLOAT128 at libstdc++ > build time and undef _GLIBCXX_USE_FLOAT128 when building user code. > >--- 8< --- > >In order to use __float128 in C++ it's necessary to check if the >compiler enabled its support too when building user code. >This patch changes the behavior at libstdc++ build by setting >ENABLE_FLOAT128, which is used to set the value of the exported macro >_GLIBCXX_USE_FLOAT128. Now that we're in stage 1 we can make this change. The patch looks right so I'll go ahead and commit it to trunk (it shouldn't interfere with testing any last-minute fixes needed for gcc-8). Thanks for fixing this, Tulio.
On 01/05/18 15:34 +0100, Jonathan Wakely wrote: >On 12/03/18 16:02 -0300, Tulio Magno Quites Machado Filho wrote: >>Changes since v1: >>- Completely rewrite of the patch to set ENABLE_FLOAT128 at libstdc++ >> build time and undef _GLIBCXX_USE_FLOAT128 when building user code. >> >>--- 8< --- >> >>In order to use __float128 in C++ it's necessary to check if the >>compiler enabled its support too when building user code. >>This patch changes the behavior at libstdc++ build by setting >>ENABLE_FLOAT128, which is used to set the value of the exported macro >>_GLIBCXX_USE_FLOAT128. > >Now that we're in stage 1 we can make this change. The patch looks >right so I'll go ahead and commit it to trunk (it shouldn't interfere >with testing any last-minute fixes needed for gcc-8). > >Thanks for fixing this, Tulio. Previously _GLIBCXX_USE_FLOAT128 would either be defined to 1 or undefined, but after this change it can be defined to 0, and the checks in <type_traits> and <bits/std_abs.h> were not adjusted to account for that. This patch restores the previous behaviour, so that when __float128 support is not found by configure the macro will be undefined instead of defined to 0. I plan to commit this tomorrow after some more testing. commit aed5af13903fa21632919269c9e7f7c4e02e8887 Author: Jonathan Wakely <jwakely@redhat.com> Date: Mon May 7 20:46:21 2018 +0100 PR libstdc++/85672 #undef _GLIBCXX_USE_FLOAT128 when not supported Restore the behaviour in GCC 8 and earlier where _GLIBCXX_USE_FLOAT128 is not defined when configure detects support is missing. This avoids having three states where the macro is either 1, 0, or undefined. PR libstdc++/85672 * include/Makefile.am [!ENABLE_FLOAT128]: Change c++config.h entry to #undef _GLIBCXX_USE_FLOAT128 instead of defining it to zero. * include/Makefile.in: Regenerate. * include/bits/c++config (_GLIBCXX_USE_FLOAT128): Move definition within conditional block. diff --git a/libstdc++-v3/include/Makefile.am b/libstdc++-v3/include/Makefile.am index ba5adda95bd..77e6dc2f6be 100644 --- a/libstdc++-v3/include/Makefile.am +++ b/libstdc++-v3/include/Makefile.am @@ -1232,10 +1232,10 @@ endif if ENABLE_FLOAT128 stamp-float128: - echo 1 > stamp-float128 + echo 'define _GLIBCXX_USE_FLOAT128 1' > stamp-float128 else stamp-float128: - echo 0 > stamp-float128 + echo 'undef _GLIBCXX_USE_FLOAT128' > stamp-float128 endif # NB: The non-empty default ldbl_compat works around an AIX sed @@ -1272,7 +1272,7 @@ ${host_builddir}/c++config.h: ${CONFIG_HEADER} \ -e "s,define _GLIBCXX_USE_DUAL_ABI, define _GLIBCXX_USE_DUAL_ABI $$dualabi," \ -e "s,define _GLIBCXX_USE_CXX11_ABI, define _GLIBCXX_USE_CXX11_ABI $$cxx11abi," \ -e "s,define _GLIBCXX_USE_ALLOCATOR_NEW, define _GLIBCXX_USE_ALLOCATOR_NEW $$allocatornew," \ - -e "s,define _GLIBCXX_USE_FLOAT128, define _GLIBCXX_USE_FLOAT128 $$float128," \ + -e "s,define _GLIBCXX_USE_FLOAT128,$$float128," \ -e "$$ldbl_compat" \ < ${glibcxx_srcdir}/include/bits/c++config > $@ ;\ sed -e 's/HAVE_/_GLIBCXX_HAVE_/g' \ diff --git a/libstdc++-v3/include/bits/c++config b/libstdc++-v3/include/bits/c++config index e34524117d6..bfe268da825 100644 --- a/libstdc++-v3/include/bits/c++config +++ b/libstdc++-v3/include/bits/c++config @@ -610,9 +610,8 @@ namespace std #endif /* Define if __float128 is supported on this host. */ +#if defined(__FLOAT128__) || defined(__SIZEOF_FLOAT128__) #define _GLIBCXX_USE_FLOAT128 -#if !defined(__FLOAT128__) && !defined(__SIZEOF_FLOAT128__) -#undef _GLIBCXX_USE_FLOAT128 #endif // End of prewritten config; the settings discovered at configure time follow.
diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4 index 3bd669a..4f37b6a 100644 --- a/libstdc++-v3/acinclude.m4 +++ b/libstdc++-v3/acinclude.m4 @@ -3062,7 +3062,7 @@ dnl Note: also checks that the types aren't standard types. dnl dnl Defines: dnl _GLIBCXX_USE_INT128 -dnl _GLIBCXX_USE_FLOAT128 +dnl ENABLE_FLOAT128 dnl AC_DEFUN([GLIBCXX_ENABLE_INT128_FLOAT128], [ @@ -3117,13 +3117,12 @@ EOF AC_MSG_CHECKING([for __float128]) if AC_TRY_EVAL(ac_compile); then - AC_DEFINE(_GLIBCXX_USE_FLOAT128, 1, - [Define if __float128 is supported on this host.]) enable_float128=yes else enable_float128=no fi AC_MSG_RESULT($enable_float128) + GLIBCXX_CONDITIONAL(ENABLE_FLOAT128, test $enable_float128 = yes) rm -f conftest* AC_LANG_RESTORE diff --git a/libstdc++-v3/config.h.in b/libstdc++-v3/config.h.in index 5a0f067..765cedc 100644 --- a/libstdc++-v3/config.h.in +++ b/libstdc++-v3/config.h.in @@ -918,9 +918,6 @@ /* Define if fchmodat is available in <sys/stat.h>. */ #undef _GLIBCXX_USE_FCHMODAT -/* Define if __float128 is supported on this host. */ -#undef _GLIBCXX_USE_FLOAT128 - /* Defined if gettimeofday is available. */ #undef _GLIBCXX_USE_GETTIMEOFDAY diff --git a/libstdc++-v3/include/Makefile.am b/libstdc++-v3/include/Makefile.am index 70a662f..ba5adda 100644 --- a/libstdc++-v3/include/Makefile.am +++ b/libstdc++-v3/include/Makefile.am @@ -1230,6 +1230,14 @@ stamp-allocator-new: echo 0 > stamp-allocator-new endif +if ENABLE_FLOAT128 +stamp-float128: + echo 1 > stamp-float128 +else +stamp-float128: + echo 0 > stamp-float128 +endif + # NB: The non-empty default ldbl_compat works around an AIX sed # oddity, see libstdc++/31957 for details. ${host_builddir}/c++config.h: ${CONFIG_HEADER} \ @@ -1241,7 +1249,8 @@ ${host_builddir}/c++config.h: ${CONFIG_HEADER} \ stamp-extern-template \ stamp-dual-abi \ stamp-cxx11-abi \ - stamp-allocator-new + stamp-allocator-new \ + stamp-float128 @date=`cat ${toplevel_srcdir}/gcc/DATESTAMP` ;\ release=`sed 's/^\([0-9]*\).*$$/\1/' ${toplevel_srcdir}/gcc/BASE-VER` ;\ ns_version=`cat stamp-namespace-version` ;\ @@ -1250,6 +1259,7 @@ ${host_builddir}/c++config.h: ${CONFIG_HEADER} \ dualabi=`cat stamp-dual-abi` ;\ cxx11abi=`cat stamp-cxx11-abi` ;\ allocatornew=`cat stamp-allocator-new` ;\ + float128=`cat stamp-float128` ;\ ldbl_compat='s,g,g,' ;\ grep "^[ ]*#[ ]*define[ ][ ]*_GLIBCXX_LONG_DOUBLE_COMPAT[ ][ ]*1[ ]*$$" \ ${CONFIG_HEADER} > /dev/null 2>&1 \ @@ -1262,6 +1272,7 @@ ${host_builddir}/c++config.h: ${CONFIG_HEADER} \ -e "s,define _GLIBCXX_USE_DUAL_ABI, define _GLIBCXX_USE_DUAL_ABI $$dualabi," \ -e "s,define _GLIBCXX_USE_CXX11_ABI, define _GLIBCXX_USE_CXX11_ABI $$cxx11abi," \ -e "s,define _GLIBCXX_USE_ALLOCATOR_NEW, define _GLIBCXX_USE_ALLOCATOR_NEW $$allocatornew," \ + -e "s,define _GLIBCXX_USE_FLOAT128, define _GLIBCXX_USE_FLOAT128 $$float128," \ -e "$$ldbl_compat" \ < ${glibcxx_srcdir}/include/bits/c++config > $@ ;\ sed -e 's/HAVE_/_GLIBCXX_HAVE_/g' \ diff --git a/libstdc++-v3/include/bits/c++config b/libstdc++-v3/include/bits/c++config index 1eb4679..e345241 100644 --- a/libstdc++-v3/include/bits/c++config +++ b/libstdc++-v3/include/bits/c++config @@ -609,4 +609,10 @@ namespace std # endif #endif +/* Define if __float128 is supported on this host. */ +#define _GLIBCXX_USE_FLOAT128 +#if !defined(__FLOAT128__) && !defined(__SIZEOF_FLOAT128__) +#undef _GLIBCXX_USE_FLOAT128 +#endif + // End of prewritten config; the settings discovered at configure time follow.