Add more bugs to the introduction

1 files changed, 23 insertions, 1 deletions

diff --git a/intro.tex b/intro.tex
index d662977..33e963d 100644
--- a/intro.tex
+++ b/intro.tex
@@ -6,6 +6,28 @@ It is even being used in high-assurance settings, such as financial services~\ci
 
 Our method is brought over from the compiler testing literature. We use a tool called Csmith~\cite{yang11_findin_under_bugs_c_compil} to generate well-formed C programs from the subset of the C language that is supported by all the HLS tools we test, and then augment each program with randomly chosen HLS-specific directives. We synthesise each C program to RTL, and use a Verilog simulator to calculate its return value. If synthesis crashes, or if this return value differs from the return value obtained by executing a binary compiled from the C program by gcc, then we have found a candidate bug. We then use trial-and-error to reduce the C program to a minimal version that still triggers a bug.
 
+\begin{figure}
+  \centering
+\begin{minted}{c}
+unsigned int b = 0x1194D7FF;
+int a[6] = {1, 1, 1, 1, 1, 1};
+
+int result() {
+  int c;
+  for (c = 0; c < 2; c++)
+    b = b >> a[c];
+  return b;
+}
+\end{minted}
+  \caption{Miscompilation bug found in Vivado 2018.3 and 2019.2 which returns \texttt{6535FF} instead of \texttt{46535FF} which is the correct result.}\label{fig:vivado_bug1}
+\end{figure}
+
 We have tested three widely used HLS tools: LegUp~\cite{canis13_legup}, Xilinx Vivado HLS~\cite{xilinx20_vivad_high_synth}, and the Intel HLS Compiler~\cite{?}. For all three tools, we were able to find valid C programs that cause crashes while compiling and valid C programs that cause wrong RTL to be generated. We have submitted a total of \ref{?} bug reports to the developers, \ref{?} of which have been confirmed and \ref{?} of which have now been fixed at the time of writing. 
 
-We hope that our work serves to stimulate efforts to improve the quality of HLS tools.
\ No newline at end of file
+We hope that our work serves to stimulate efforts to improve the quality of HLS tools.
+
+
+%%% Local Variables:
+%%% mode: latex
+%%% TeX-master: "main"
+%%% End: