Add slides about fixpoint

slides.tex

@@ -17,7 +17,7 @@
 \usepackage{multirow}
 \usepackage[many]{tcolorbox}
 \usepackage[absolute,overlay]{textpos}
-\usetikzlibrary{arrows.meta}
+\usetikzlibrary{arrows.meta,shapes}
 
 \usepackage{texlib/my_listings}
 \usepackage{texlib/specific}
@@ -646,4 +646,89 @@ Segmentation fault.
     \end{center}
 \end{frame}
 
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\section*{Extra slides}
+
+\begin{frame}[noframenumbering]
+\end{frame}
+
+\begin{frame}[noframenumbering]{Fixpoint upon control flow merge}
+    \begin{columns}
+        \begin{column}{0.3\textwidth}
+            \begin{tikzpicture}
+                \begin{scope}[every node/.style={rectangle,thick,draw,scale=0.95}]
+                    \node (if) at (0, 5) {\lstbash{if cnd}};
+                    \node (then) at (-1, 3) { \lstbash{then A} };
+                    \node (else) at (1, 3) { \lstbash{else B} };
+                    \node (after) at (0, 1) { \lstbash{C} };
+                \end{scope}
+                \node [circle, thick, draw, minimum size=3em, color=red] (circafter) at (0, 1) {};
+                \begin{scope}[>={Stealth[black]}, every path/.style={draw=black,very thick}]
+                    \path [->] (if) -- (then);
+                    \path [->] (if) -- (else);
+                    \path [->] (then) -- (after);
+                    \path [->] (else) -- (after);
+                \end{scope}
+            \end{tikzpicture}
+        \end{column}
+        \begin{column}{0.6\textwidth}
+            \begin{center}
+                If eg.
+                \[
+                    CFA(A) = c-48 \qquad CFA(B) = c-52
+                \]
+                no possible unwinding data for C, \alert{even for the
+                compiler}!
+
+                \vspace{1em}
+                Also, \alert{no possible clean function postlude}!
+
+                \vspace{2em}
+                $\implies$ $CFA(A) = CFA(B)$ and merge is immediate
+            \end{center}
+        \end{column}
+    \end{columns}
+\end{frame}
+
+\begin{frame}[noframenumbering]{Fixpoint upon loop control flow merge}
+    \begin{columns}
+        \begin{column}{0.3\textwidth}
+            \begin{tikzpicture}
+                \begin{scope}[every node/.style={rectangle,thick,draw,scale=0.95}]
+                    \node (inbound) at (0, 7) {\lstbash{A}};
+                    \node (while) at (0, 5) {\lstbash{for i in ...}};
+                    \node (do) at (0, 3) { \lstbash{do a = array[i]; B} };
+                    \node (done) at (0, 1) { \lstbash{C} };
+                \end{scope}
+                \node [ellipse, thick, draw, minimum width=10em, minimum height=3em, color=red] (circafter) at (0, 3) {};
+                \begin{scope}[>={Stealth[black]}, every path/.style={draw=black,very thick}]
+                    \path [->] (inbound) -- (while);
+                    \path [->] (while) edge[bend right] (do);
+                    \path [->] (do) -- (done);
+                    \path [->] (do) edge[bend right] (while);
+                \end{scope}
+            \end{tikzpicture}
+        \end{column}
+        \begin{column}{0.6\textwidth}
+            \begin{center}
+                {\large\alert{Variable stack frame size!}}
+
+                \vspace{1em}
+
+                We cannot hope for an invariant\dots\\
+                but the compiler cannot
+                either.
+
+                \vspace{1em}
+
+                {
+                    \large\alert{$\implies$} the compiler will \alert{fallback to
+                    \reg{rbp}}\\
+                }
+                even with \lstbash{--fomit-frame-pointer}
+            \end{center}
+        \end{column}
+    \end{columns}
+\end{frame}
+
 \end{document}