[LangRef] Add a clarifying example for undef

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281570 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/docs/LangRef.rst b/docs/LangRef.rst
index 917a546..e156245 100644 (file)
--- a/docs/LangRef.rst
+++ b/docs/LangRef.rst
@@ -2834,6 +2834,9 @@ bits. Any output bit can have a zero or one depending on the input bits.
     Safe:
       %A = -1
       %B = 0
+    Safe:
+      %A = %X  ;; By choosing undef as 0
+      %B = %X  ;; By choosing undef as -1
     Unsafe:
       %A = undef
       %B = undef