Add missing __builtin_bitreverse8

Also add documentation for bitreverse builtins

llvm-svn: 264203

1 files changed, 27 insertions, 0 deletions

diff --git a/clang/docs/LanguageExtensions.rst b/clang/docs/LanguageExtensions.rst
index baca28e8dc7..1f2bc293870 100644
--- a/clang/docs/LanguageExtensions.rst
+++ b/clang/docs/LanguageExtensions.rst
@@ -1505,6 +1505,33 @@ C-style cast applied to each element of the first argument.
 
 Query for this feature with ``__has_builtin(__builtin_convertvector)``.
 
+``__builtin_bitreverse``
+---------------------
+
+* ``__builtin_bitreverse8``
+* ``__builtin_bitreverse16``
+* ``__builtin_bitreverse32``
+* ``__builtin_bitreverse64``
+
+**Syntax**:
+
+.. code-block:: c++
+     __builtin_bitreverse32(x)
+
+**Examples**:
+
+.. code-block:: c++
+      uint8_t rev_x = __builtin_bitreverse8(x);
+      uint16_t rev_x = __builtin_bitreverse16(x);
+      uint32_t rev_y = __builtin_bitreverse32(y);
+      uint64_t rev_z = __builtin_bitreverse64(z);
+
+**Description**:
+
+The '``__builtin_bitreverse``' family of builtins is used to reverse
+the bitpattern of an integer value; for example ``0b10110110`` becomes
+``0b01101101``.
+
 ``__builtin_unreachable``
 -------------------------