--- a/hws/hw09.tex	Thu Oct 05 14:36:54 2023 +0100
+++ b/hws/hw09.tex	Fri Oct 13 15:07:37 2023 +0100
@@ -95,7 +95,7 @@
 
 \item As an optimisation technique, a compiler might want to detect `dead code' and
   not generate anything for this code. Why does this optimisation technique have the
-  potential of speeding up the run-time of a program? (Hint: On what CPUs are programs
+  potential of speeding up the run-time of a program? (Hint: On what kind of CPUs are programs
   run nowadays?)
 
 \item In an earlier question, we analysed the advantages of having a lexer-phase
@@ -115,13 +115,22 @@
 \item What is the difference between a parse tree and an abstract
   syntax tree? Give some simple examples for each of them.
 
-
-\item Give a description of how the Brzozowski matcher works. 
-  The description should be coherent and logical.
+\item What are the two main features of code in
+  static single assignment form (SSA)?
 
-\item Give a description of how a compiler for the While-language can
-  be implemented. You should assume you are producing code for the JVM.
-  The description should be coherent and logical.
+  \solution{
+    Variables are only assigned once and all operations are
+    primitive (in the sense of simple arithmetic operations,
+    function calls and so on).
+  }
+
+  
+%\item Give a description of how the Brzozowski matcher works. 
+%  The description should be coherent and logical.
+
+%\item Give a description of how a compiler for the While-language can
+%  be implemented. You should assume you are producing code for the JVM.
+%  The description should be coherent and logical.
 
   
 \item \POSTSCRIPT