<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""><div class=""><div><blockquote type="cite" class=""><div class=""><div class="gmail_quote" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;"><div class=""><br class=""></div><div class="">What's up with this giant immediate we're now generating instead of an imm8? Seems worse.</div></div></div></blockquote><br class=""></div><div>It’s a known issue: <a href="https://urldefense.proofpoint.com/v2/url?u=https-3A__llvm.org_bugs_show-5Fbug.cgi-3Fid-3D24085&d=AwMFaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=mQ4LZ2PUj9hpadE3cDHZnIdEwhEBrbAstXeMaFoB9tg&m=F4lGMAHoCZhk9ndpMJCAAKGY65AilBEh32VjzUoN0PI&s=Wsa17r8ILGuq_nrg3pODe6pppwvgbJTQbkjQeWWdlWI&e=" class="">https://llvm.org/bugs/show_bug.cgi?id=24085</a>. It’s likely a backend problem; computeKnownBits decides that the constant can be shrunk (which we already do in a lot of places, this just adds one more), so sometimes enhancing computeKnownBits can cause de-optimizations if the backend doesn’t know how to optimize the constant appropriately.</div><div><br class=""></div><div>The reviewers on Phab decided we should commit it and file a bug report about the deoptimization, since better KnownBits tracking *should* always be better.</div><div><div class=""><br class=""></div><div class="">—escha</div></div><br class=""></div></body></html>