\documentclass{standalone}

\usepackage{tikz}
\usepackage{tikz-timing}
\usetikzlibrary{patterns}
\usepackage{newpxtext}
\usepackage{newpxmath}

\definecolor{s1col}{HTML}{7fc97f}
\definecolor{s2col}{HTML}{beaed4}
\definecolor{s3col}{HTML}{fdc086}
\definecolor{s4col}{HTML}{ffff99}
\definecolor{s5col}{HTML}{386cb0}

\begin{document}
      \begin{tikztimingtable}[timing/d/background/.style={fill=white},timing/yunit=15pt]
        clk & 1L 4{7C} 1C \\
        r1  & 8D{} [fill=s2col]7D{if(p1) r2 + r4} [fill=white]15D{}\\
        r2  & 1D{} [fill=s1col]7D{r1 + r4} [fill=white]22D{} \\
        r3 & 1D{} [fill=s3col]14D{if(!p2 \&\& !p1) r1 * r1} [postaction={pattern=north west lines,pattern
          color=s5col},fill=s4col]14D{if(p2) r1 * r4 || if(!p2) r3 * r3} [fill=white]1D{}\\
      \end{tikztimingtable}
\end{document}