================
@@ -96,6 +100,47 @@ the ``<cmath>`` header file to conditionally make a
function constexpr whenever
the constant evaluation of the corresponding builtin (for example,
``std::fmax`` calls ``__builtin_fmax``) is supported in Clang.
+``__has_target_builtin``
+------------------------
+
+This function-like macro takes a single identifier argument that is the name of
+a builtin function, a builtin pseudo-function (taking one or more type
+arguments), or a builtin template.
+It evaluates to 1 if the builtin is supported on the current target or 0 if
not.
+
+``__has_builtin`` and ``__has_target_builtin`` behave identically for normal
C++ compilations.
+
+For heterogeneous compilations that see source code intended for more than one
target:
+
+``__has_builtin`` returns true if the builtin is known to the compiler
+(i.e. it's available via one of the targets), but makes no promises whether
it's available on the current target.
+The compiler can parse it, but not necessarily generate code for it.
+
+``__has_target_builtin`` returns true if the builtin can actually be generated
for the current target.
+
+It can be used like this:
+
+.. code-block:: c++
+
+ #ifdef __CUDA__
+ #if __has_target_builtin(__builtin_trap)
+ __builtin_trap();
+ #else
+ abort();
+ #endif
+ #else // !CUDA
+ #if __has_builtin(__builtin_trap)
+ __builtin_trap();
+ #else
+ abort();
+ #endif
----------------
jhuber6 wrote:
```suggestion
#else // !CUDA
#if __has_builtin(__builtin_trap)
__builtin_trap();
#else
abort();
#endif
```
Is this still necessary now that we allow it on all targets?
https://github.com/llvm/llvm-project/pull/126324
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