Update mini docs

svn path=/trunk/mono/; revision=13697

diff --git a/docs/mini-doc.txt b/docs/mini-doc.txt
index cfe1a91d365b1ccb52ee51376966bd7df55910fc..4c6f57c42d0fc2756b51adf127b581e892b90d67 100644 (file)
--- a/docs/mini-doc.txt
+++ b/docs/mini-doc.txt
@@ -525,18 +525,48 @@
 
 * SSA-based optimizations
 
-       SSA form simplifies many optimization because each variable has exactly
-       one definition site. All uses of a variable are "dominated" by its
-       definition, which enables us to implement algorithm like:
+       SSA form simplifies many optimization because each variable
+       has exactly one definition site.  This means that each
+       variable is only initialized once.  
 
-               * conditional constant propagation
+       For example, code like this:
 
-               * array bound check removal
+           a = 1
+           ..
+           a = 2
+           call (a)
 
-               * dead code elimination
+       Is internally turned into:
 
-       And we can implement those algorithm in a efficient way using SSA. 
+           a1 = 1
+           ..
+           a2 = 2
+           call (a2)
 
+       In the presence of branches, like:
+
+           if (x)
+                a = 1
+           else
+                a = 2
+
+            call (a)
+
+       The code is turned into:
+
+           if (x)
+                a1 = 1;
+           else
+                a2 = 2;
+           a3 = phi (a1, a2)
+           call (a3)
+
+       All uses of a variable are "dominated" by its definition
+
+       This representation is useful as it simplifies the
+       implementation of a number of optimizations like conditional
+       constant propagation, array bounds check removal and dead code
+       elimination. 
 
 * Register allocation.
 

diff --git a/mono/mini/mini-doc.txt b/mono/mini/mini-doc.txt
index cfe1a91d365b1ccb52ee51376966bd7df55910fc..4c6f57c42d0fc2756b51adf127b581e892b90d67 100644 (file)
--- a/mono/mini/mini-doc.txt
+++ b/mono/mini/mini-doc.txt
@@ -525,18 +525,48 @@
 
 * SSA-based optimizations
 
-       SSA form simplifies many optimization because each variable has exactly
-       one definition site. All uses of a variable are "dominated" by its
-       definition, which enables us to implement algorithm like:
+       SSA form simplifies many optimization because each variable
+       has exactly one definition site.  This means that each
+       variable is only initialized once.  
 
-               * conditional constant propagation
+       For example, code like this:
 
-               * array bound check removal
+           a = 1
+           ..
+           a = 2
+           call (a)
 
-               * dead code elimination
+       Is internally turned into:
 
-       And we can implement those algorithm in a efficient way using SSA. 
+           a1 = 1
+           ..
+           a2 = 2
+           call (a2)
 
+       In the presence of branches, like:
+
+           if (x)
+                a = 1
+           else
+                a = 2
+
+            call (a)
+
+       The code is turned into:
+
+           if (x)
+                a1 = 1;
+           else
+                a2 = 2;
+           a3 = phi (a1, a2)
+           call (a3)
+
+       All uses of a variable are "dominated" by its definition
+
+       This representation is useful as it simplifies the
+       implementation of a number of optimizations like conditional
+       constant propagation, array bounds check removal and dead code
+       elimination. 
 
 * Register allocation.