release/20.x: [libc++] Also provide an alignment assumption for vector in C++03 mode (#124839) #125860
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@llvm/pr-subscribers-libcxx Author: None (llvmbot) ChangesBackport ccb08b9 Requested by: @ldionne Full diff: https://github.com/llvm/llvm-project/pull/125860.diff 1 Files Affected:
diff --git a/libcxx/include/__vector/vector.h b/libcxx/include/__vector/vector.h
index 66cb622e2096330..bad676a56a8e643 100644
--- a/libcxx/include/__vector/vector.h
+++ b/libcxx/include/__vector/vector.h
@@ -783,14 +783,18 @@ class _LIBCPP_TEMPLATE_VIS vector {
_LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __move_assign_alloc(vector&, false_type) _NOEXCEPT {}
- static _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI pointer __add_alignment_assumption(pointer __p) _NOEXCEPT {
-#ifndef _LIBCPP_CXX03_LANG
- if constexpr (is_pointer<pointer>::value) {
- if (!__libcpp_is_constant_evaluated()) {
- return static_cast<pointer>(__builtin_assume_aligned(__p, alignof(decltype(*__p))));
- }
+ template <class _Ptr = pointer, __enable_if_t<is_pointer<_Ptr>::value, int> = 0>
+ static _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI _LIBCPP_NO_CFI pointer
+ __add_alignment_assumption(_Ptr __p) _NOEXCEPT {
+ if (!__libcpp_is_constant_evaluated()) {
+ return static_cast<pointer>(__builtin_assume_aligned(__p, _LIBCPP_ALIGNOF(decltype(*__p))));
}
-#endif
+ return __p;
+ }
+
+ template <class _Ptr = pointer, __enable_if_t<!is_pointer<_Ptr>::value, int> = 0>
+ static _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI _LIBCPP_NO_CFI pointer
+ __add_alignment_assumption(_Ptr __p) _NOEXCEPT {
return __p;
}
};
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llvm#124839) There's no reason not to, and it's easy enough to do using enable_if. As a drive-by change, also add a missing _LIBCPP_NO_CFI attribute on __add_alignment_assumption. (cherry picked from commit ccb08b9)
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@ldionne (or anyone else). If you would like to add a note about this fix in the release notes (completely optional). Please reply to this comment with a one or two sentence description of the fix. When you are done, please add the release:note label to this PR. |
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Backport ccb08b9
Requested by: @ldionne