FCLC<p>Clang/LLVM friends, trying to understand *why* Clang (18) doesn't see through what seems to me like an obvious optimization. </p><p><a href="https://mast.hpc.social/tags/compiler_explorer" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>compiler_explorer</span></a> link here, explanation of what I don't understand follows: <br><a href="https://godbolt.org/z/j8WqsMjb6" rel="nofollow noopener" translate="no" target="_blank"><span class="invisible">https://</span><span class="">godbolt.org/z/j8WqsMjb6</span><span class="invisible"></span></a></p><p>Going through Hackers delight and doing some of the dirt simple exercises, I dumped the assembly for Chapter 1 exercise 2 "loop that goes from 1 to 0xFFFFFFFF". (changed to not fault in CE) </p><p>(continues in next post, but putting hashtags here)</p><p><a href="https://mast.hpc.social/tags/clang" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>clang</span></a> <a href="https://mast.hpc.social/tags/compilers" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>compilers</span></a> <a href="https://mast.hpc.social/tags/SIMD" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>SIMD</span></a></p>