="keyword">constexpr</span> <span class="keyword">auto</span> <span class="identifier">if_else</span><span class="special">(</span><span class="identifier">Expr1</span> <span class="special">&amp;&amp;</span> expr1<span class="special">,</span> <span class="identifier">Expr2</span> <span class="special">&amp;&amp;</span> expr2<span class="special">,</span> <span class="identifier">Expr3</span> <span class="special">&amp;&amp;</span> expr3<span class="special">)</span><span class="special">;</span></pre></di