Revert "[Clang][C++23] Implement P2448R2: Relaxing some constexpr
restrictions (#77753)"
This reverts commit 99500e8c08a4d941acb8a7eb00523296fb2acf7a because it
causes a behavior change for std=c++20. See
https://github.com/llvm/llvm-project/pull/77753.
Per
https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2022/p2448r2.html
function/constructor/destructor can be marked `constexpr` even though it
never produces a constant expression.
Non-literal types as return types and parameter types of functions
marked `constexpr` are also allowed.
Since this is not a DR, the diagnostic messages are still preserved for
C++ standards older than C++23.
This patch fixes initializing temporaries, which are currently initialized
without an address space, meaning that no constructor can ever be applicable.
Now they will be constructed in the private addrspace.
Fixes the second issue in PR43296.
Reviewed By: Anastasia
Differential Revision: https://reviews.llvm.org/D107553
This fixes the prioritization of address spaces when choosing a
constructor, stopping them from being considered equally good,
which made the construction of types that could be constructed
by more than one of the constructors.
It does this by preferring the most specific address space,
which is decided by seeing if one of the address spaces is
a superset of the other, and preferring the other.
Fixes: PR50329
Reviewed By: Anastasia
Differential Revision: https://reviews.llvm.org/D102850
This fixes the initialization of objects in the __constant
address space that occurs when declaring the object.
Fixes part of PR42566
Reviewed By: Anastasia
Differential Revision: https://reviews.llvm.org/D102248
