git: 3e7b96764a80 - stable/13 - <type_traits>: Avoid instantiating a pointer type in std::decay<>.

The branch stable/13 has been updated by dim:

URL: https://cgit.FreeBSD.org/src/commit/?id=3e7b96764a80c7851421af60f800587b2f94b697

commit 3e7b96764a80c7851421af60f800587b2f94b697
Author:     John Baldwin <jhb@FreeBSD.org>
AuthorDate: 2022-11-24 00:10:05 +0000
Commit:     Dimitry Andric <dim@FreeBSD.org>
CommitDate: 2023-04-09 14:39:46 +0000

    <type_traits>: Avoid instantiating a pointer type in std::decay<>.
    
    GCC expands the pointer type in this conditional expression even for
    template types _Up that are not arrays.  This raises an error when
    std::decay<> is used with reference types (as is done in LLVM's
    sources).  Using add_pointer<> causes GCC to only instantiate a
    pointer type for array types.
    
    A similar change to this commit (albeit reworked due to upstream
    changes) has been merged to libc++ in commit
    26068c6e60324ed866a1ca2afb5cb5eb0aaf015b.
    
    In file included from /usr/obj/usr/src/amd64.amd64/tmp/usr/include/c++/v1/__compare/ordering.h:13,
                     from /usr/obj/usr/src/amd64.amd64/tmp/usr/include/c++/v1/__compare/common_comparison_category.h:12,
                     from /usr/obj/usr/src/amd64.amd64/tmp/usr/include/c++/v1/tuple:168,
                     from /usr/src/contrib/llvm-project/llvm/include/llvm/ADT/DenseMapInfo.h:20,
                     from /usr/src/contrib/llvm-project/llvm/include/llvm/ADT/DenseMap.h:17,
                     from /usr/src/contrib/llvm-project/llvm/lib/Transforms/Scalar/GVNHoist.cpp:36:
    /usr/obj/usr/src/amd64.amd64/tmp/usr/include/c++/v1/type_traits: In instantiation of 'struct std::__1::__decay<llvm::CHIArg&, true>':
    /usr/obj/usr/src/amd64.amd64/tmp/usr/include/c++/v1/type_traits:1591:89:   required from 'struct std::__1::decay<llvm::CHIArg&&>'
    /usr/obj/usr/src/amd64.amd64/tmp/usr/include/c++/v1/__utility/pair.h:132:16:   required by substitution of 'template<class _Tuple, typename std::__1::enable_if<typename std::__1::conditional<(std::__1::__tuple_like_with_size<_Tuple, 2, typename std::__1::__uncvref<_Tp>::type>::value && (! std::__1::is_same<typename std::__1::decay<_Tp>::type, std::__1::pair<llvm::BasicBlock*, llvm::SmallVector<llvm::CHIArg, 2> > >::value)), std::__1::pair<llvm::BasicBlock*, llvm::SmallVector<llvm::CHIArg, 2> >::_CheckTupleLikeConstructor, std::__1::__check_tuple_constructor_fail>::type::__enable_implicit<_Tuple>(), void>::type* <anonymous> > constexpr std::__1::pair<llvm::BasicBlock*, llvm::SmallVector<llvm::CHIArg, 2> >::pair(_Tuple&&) [with _Tuple = llvm::CHIArg&&; typename std::__1::enable_if<typename std::__1::conditional<(std::__1::__tuple_like_with_size<_Tuple, 2, typename std::__1::__uncvref<_Tp>::type>::value && (! std::__1::is_same<typename std::__1::decay<_Tp>::type, std::__1::pair<llvm
 ::BasicBlock*, llvm::SmallVector<llvm::CHIArg, 2> > >::value)), std::__1::pair<llvm::BasicBlock*, llvm::SmallVector<llvm::CHIArg, 2> >::_CheckTupleLikeConstructor, std::__1::__check_tuple_constructor_fail>::type::__enable_implicit<_Tuple>(), void>::type* <anonymous> = <missing>]'
    /usr/src/contrib/llvm-project/llvm/lib/Transforms/Scalar/GVNHoist.cpp:892:51:   required from here
    /usr/obj/usr/src/amd64.amd64/tmp/usr/include/c++/v1/type_traits:1582:30: error: forming pointer to reference type 'std::__1::remove_extent<llvm::CHIArg&>::type' {aka 'llvm::CHIArg&'}
     1582 |                      >::type type;
          |                              ^~~~
    
    Reviewed by:    dim
    Differential Revision:  https://reviews.freebsd.org/D36898
    
    (cherry picked from commit c36de97088a2b9141cdaf2fae2a7f41bf820ffa0)
---
 contrib/llvm-project/libcxx/include/type_traits | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/contrib/llvm-project/libcxx/include/type_traits b/contrib/llvm-project/libcxx/include/type_traits
index 3391999675a0..daf031e475f7 100644
--- a/contrib/llvm-project/libcxx/include/type_traits
+++ b/contrib/llvm-project/libcxx/include/type_traits
@@ -1572,7 +1572,7 @@ public:
     typedef _LIBCPP_NODEBUG typename conditional
                      <
                          is_array<_Up>::value,
-                         typename remove_extent<_Up>::type*,
+                         typename add_pointer<typename remove_extent<_Up>::type>::type,
                          typename conditional
                          <
                               is_function<_Up>::value,