diff --git a/llvm/docs/CodeGenerator.rst b/llvm/docs/CodeGenerator.rst
--- a/llvm/docs/CodeGenerator.rst
+++ b/llvm/docs/CodeGenerator.rst
@@ -719,9 +719,12 @@
 ---------------------
 
 Instruction Selection is the process of translating LLVM code presented to the
-code generator into target-specific machine instructions.  There are several
-well-known ways to do this in the literature.  LLVM uses a SelectionDAG based
-instruction selector.
+code generator into target-specific machine instructions.  There are several 
+well-known ways to do this in the literature.  LLVM have three types of
+instruction selector.  1. SelectionDAG 2. FastIsel 3. GlobalIsel.
+
+`GlobalIsel <https://llvm.org/docs/GlobalISel/index.html>`_ is intended to 
+be a replacement of SelectionDAG and FastIsel. 
 
 Portions of the DAG instruction selector are generated from the target
 description (``*.td``) files.  Our goal is for the entire instruction selector