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.

From-SVN: r260043
This commit is contained in:
Jonathan Wakely 2018-05-08 14:05:04 +01:00 committed by Jonathan Wakely
parent 50e461dfe3
commit 41c3db9f28
4 changed files with 16 additions and 8 deletions

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@ -1,3 +1,12 @@
2018-05-08 Jonathan Wakely <jwakely@redhat.com>
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.
2018-05-07 Jonathan Wakely <jwakely@redhat.com>
* doc/xml/manual/using.xml (table.cmd_options): Document that the

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@ -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' \

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@ -1663,9 +1663,9 @@ stamp-host: ${host_headers} ${bits_host_headers} ${ext_host_headers} ${host_head
@ENABLE_ALLOCATOR_NEW_FALSE@ echo 0 > stamp-allocator-new
@ENABLE_FLOAT128_TRUE@stamp-float128:
@ENABLE_FLOAT128_TRUE@ echo 1 > stamp-float128
@ENABLE_FLOAT128_TRUE@ echo 'define _GLIBCXX_USE_FLOAT128 1' > stamp-float128
@ENABLE_FLOAT128_FALSE@stamp-float128:
@ENABLE_FLOAT128_FALSE@ echo 0 > stamp-float128
@ENABLE_FLOAT128_FALSE@ echo 'undef _GLIBCXX_USE_FLOAT128' > stamp-float128
# NB: The non-empty default ldbl_compat works around an AIX sed
# oddity, see libstdc++/31957 for details.
@ -1701,7 +1701,7 @@ ${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' \

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@ -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.