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This patch updates the documentation about `__builtin_memcpy_inline` and reorders the sections so it is more consitent and understandable. Repository: rG LLVM Github Monorepo https://reviews.llvm.org/D87458 Files: clang/docs/LanguageExtensions.rst Index: clang/docs/LanguageExtensions.rst =================================================================== --- clang/docs/LanguageExtensions.rst +++ clang/docs/LanguageExtensions.rst @@ -2408,20 +2408,6 @@ Memory builtins --------------- - * ``__builtin_memcpy_inline`` - -.. code-block:: c - - void __builtin_memcpy_inline(void *dst, const void *src, size_t size); - -``__builtin_memcpy_inline(dst, src, size)`` is identical to -``__builtin_memcpy(dst, src, size)`` except that the generated code is -guaranteed not to call any external functions. See LLVM IR `llvm.memcpy.inline -<https://llvm.org/docs/LangRef.html#llvm-memcpy-inline-intrinsic>`_ Intrinsic -for more information. - -Note that the `size` argument must be a compile time constant. - Clang provides constant expression evaluation support for builtin forms of the following functions from the C standard library headers ``<string.h>`` and ``<wchar.h>``: @@ -2439,7 +2425,27 @@ given size is an exact multiple of the element size that is no greater than the number of elements accessible through the source and destination operands. -Constant evaluation support is not yet provided for ``__builtin_memcpy_inline``. +Guaranteed inlined copy +^^^^^^^^^^^^^^^^^^^^^^^ + +.. code-block:: c + + void __builtin_memcpy_inline(void *dst, const void *src, size_t size); + + +``__builtin_memcpy_inline`` has been designed as a building block for efficient +``memcpy`` implementations. It is identical to ``__builtin_memcpy`` but also +guarantees not to call any external functions. See LLVM IR `llvm.memcpy.inline +<https://llvm.org/docs/LangRef.html#llvm-memcpy-inline-intrinsic>`_ Intrinsic +for more information. + +This is useful to implement a custom version of ``memcpy``, implemement a +``libc`` memcpy or work around the absence of a ``libc``. + +Note that the `size` argument must be a compile time constant. + +Note that this intrinsic cannot yet be called in a ``constexpr`` context. + Atomic Min/Max builtins with memory ordering --------------------------------------------
Index: clang/docs/LanguageExtensions.rst =================================================================== --- clang/docs/LanguageExtensions.rst +++ clang/docs/LanguageExtensions.rst @@ -2408,20 +2408,6 @@ Memory builtins --------------- - * ``__builtin_memcpy_inline`` - -.. code-block:: c - - void __builtin_memcpy_inline(void *dst, const void *src, size_t size); - -``__builtin_memcpy_inline(dst, src, size)`` is identical to -``__builtin_memcpy(dst, src, size)`` except that the generated code is -guaranteed not to call any external functions. See LLVM IR `llvm.memcpy.inline -<https://llvm.org/docs/LangRef.html#llvm-memcpy-inline-intrinsic>`_ Intrinsic -for more information. - -Note that the `size` argument must be a compile time constant. - Clang provides constant expression evaluation support for builtin forms of the following functions from the C standard library headers ``<string.h>`` and ``<wchar.h>``: @@ -2439,7 +2425,27 @@ given size is an exact multiple of the element size that is no greater than the number of elements accessible through the source and destination operands. -Constant evaluation support is not yet provided for ``__builtin_memcpy_inline``. +Guaranteed inlined copy +^^^^^^^^^^^^^^^^^^^^^^^ + +.. code-block:: c + + void __builtin_memcpy_inline(void *dst, const void *src, size_t size); + + +``__builtin_memcpy_inline`` has been designed as a building block for efficient +``memcpy`` implementations. It is identical to ``__builtin_memcpy`` but also +guarantees not to call any external functions. See LLVM IR `llvm.memcpy.inline +<https://llvm.org/docs/LangRef.html#llvm-memcpy-inline-intrinsic>`_ Intrinsic +for more information. + +This is useful to implement a custom version of ``memcpy``, implemement a +``libc`` memcpy or work around the absence of a ``libc``. + +Note that the `size` argument must be a compile time constant. + +Note that this intrinsic cannot yet be called in a ``constexpr`` context. + Atomic Min/Max builtins with memory ordering --------------------------------------------
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