http://kaistriega.com/tags/windows/Recent content in windows on Kai StriegaHugoen-usSat, 08 Aug 2026 09:00:00 +1000http://kaistriega.com/blog/msvc-internal-compiler-error/Sat, 08 Aug 2026 09:00:00 +1000http://kaistriega.com/blog/msvc-internal-compiler-error/<p>Here is a C file:</p> <div class="highlight"> <pre class="chroma"><code><span style="display:flex;"><span><span style="color:#66d9ef">int</span> <span style="color:#a6e22e">f</span>(<span style="color:#66d9ef">double</span> x) { <span style="color:#66d9ef">return</span> <span style="color:#a6e22e">__builtin_isnan</span>(x); }</span></span></code></pre> </div> <p>Here is what Microsoft&rsquo;s C compiler does with it:</p> <div class="highlight"> <pre class="chroma"><code><span style="display:flex;"><span>C:\Users\Kai\Documents&gt;cl /c /Od isnan_ice.c </span></span><span style="display:flex;"><span>Microsoft (R) C/C++ Optimizing Compiler Version 19.51.36252 for x64 </span></span><span style="display:flex;"><span>Copyright (C) Microsoft Corporation. All rights reserved. </span></span><span style="display:flex;"><span> </span></span><span style="display:flex;"><span>isnan_ice.c </span></span><span style="display:flex;"><span>C:\Users\Kai\Documents\isnan_ice.c : fatal error C1001: Internal compiler error. </span></span><span style="display:flex;"><span>(compiler file &#39;D:\a\_work\1\s\src\vctools\Compiler\Utc\src\p2\main.cpp&#39;, line 262) </span></span><span style="display:flex;"><span> To work around this problem, try simplifying or changing the program near the locations listed above.</span></span></code></pre> </div> <p>The process exits with <code>-1073741819</code>, which is <code>0xC0000005</code>, which is an access violation. The compiler didn&rsquo;t decide to give up. It fell over.</p>