Added some test cases of missed opportunities to use unpckl/unpckh shuffles

[oota-llvm.git] / docs / LangRef.rst

diff --git a/docs/LangRef.rst b/docs/LangRef.rst
index f086fbe3e0b7da24471348a6ea2633000f0e3be2..f7b865d0de0259a3add7392bcb68fc61c767b451 100644 (file)
--- a/docs/LangRef.rst
+++ b/docs/LangRef.rst
@@ -1236,9 +1236,12 @@ example:
     normally. This produces undefined behavior at runtime if the
     function ever does dynamically return.
 ``nounwind``
-    This function attribute indicates that the function never returns
-    with an unwind or exceptional control flow. If the function does
-    unwind, its runtime behavior is undefined.
+    This function attribute indicates that the function never raises an
+    exception. If the function does raise an exception, its runtime
+    behavior is undefined. However, functions marked nounwind may still
+    trap or generate asynchronous exceptions. Exception handling schemes
+    that are recognized by LLVM to handle asynchronous exceptions, such
+    as SEH, will still provide their implementation defined semantics.
 ``optnone``
     This function attribute indicates that the function is not optimized
     by any optimization or code generator passes with the