MatCat.OpenSource/8sa1-gcc
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

libstdc++: Disable "ALT128" long double support for Clang

Browse Source 
Clang does not currently support the __ibm128 type [1] and only supports
the __ieee128 type in the unreleased 12.0.0 version [2]. That means it
is not possible to provide support for -mabi=ieeelongdouble with Clang
in an ABI compatible way (as we do for GCC by defining new facets and
other types in the __gnu_cxx_ldbl128 namespace).

By preventing the definition of _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT when
compiling with Clang, all uses of __ibm128 and __ieee128 types will be
disabled. This can be revisited in future when Clang supports the types
(and provides a way to detect that support using the preprocessor).

[1] https://reviews.llvm.org/D93377
[2] https://reviews.llvm.org/D97846

libstdc++-v3/ChangeLog:

	* include/bits/c++config (_GLIBCXX_LONG_DOUBLE_ALT128_COMPAT):
	Do not define when compiling with Clang.
This commit is contained in:
Jonathan Wakely 2021-03-23 13:08:32 +00:00
parent 831f9f768e
commit baef0cffb5
1 changed files with 4 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
libstdc++-v3/include/bits/c++config
View File

@ -425,9 +425,12 @@ _GLIBCXX_END_NAMESPACE_VERSION
// GLIBCXX_ABI Deprecated
// Define if compatibility should be provided for -mlong-double-64.
#undef _GLIBCXX_LONG_DOUBLE_COMPAT
// Define if compatibility should be provided for alternative 128-bit long
// double formats.
// double formats. Not possible for Clang until __ibm128 is supported.
#ifndef __clang__
#undef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT
#endif
// Inline namespaces for long double 128 modes.
#if defined _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT \