<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""><div><blockquote type="cite" class=""><div class="">On Feb 3, 2015, at 10:20 AM, Chris Sears <<a href="mailto:chris.sears@gmail.com" class="">chris.sears@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class=""><div class="gmail_extra">I was using this GCC compiler comparison site. It's well done but unfortunately it's not up to date. The author Matt Godbolt said he was updating it:</div><div class="gmail_extra"><br class=""></div><blockquote style="margin:0 0 0 40px;border:none;padding:0px" class=""><div class="gmail_extra"><a href="http://gcc.godbolt.org/#" target="_blank" class="">http://gcc.godbolt.org/#</a></div></blockquote><div class="gmail_extra"><br class=""></div><div class="gmail_extra">No, I do not have 3.4.1 but 3.5 is the current XCode release. It's pretty much already narrowed.</div><div class="gmail_extra"><br class=""></div><div class="gmail_extra"><blockquote style="margin:0 0 0 40px;border:none;padding:0px" class=""><div class="gmail_extra">3.4.1 generates correct assembly (except bug #2 is here as well, see below)</div></blockquote><blockquote style="margin:0 0 0 40px;border:none;padding:0px" class=""><div class="gmail_extra">3.5 (XCode) generates correct IR and bad assembly</div></blockquote><div class="gmail_extra"><br class=""></div>So the problem seems to show up with 3.5. The attached IR is from 3.5 XCode clang -S -O3 -emit-llvm newtst.c.<br class=""></div><div class="gmail_extra"><br class=""></div><div class="gmail_extra">There are TWO bugs here. There's the Constant Hoisting bug (#1) and the failure to match a AND/CMP (#2). My current theory for #1 is that Constant Hoisting for the X86 is relatively recent or that Costing changed and that what we're seeing is that it worked correctly before. I think my proposed patch is correct and I'd recommend the ARM folks look at it.</div></div></div></blockquote><div><br class=""></div><div>I may have missed on email, did you send a patch?</div><div><br class=""></div><div>Thanks,</div><div><br class=""></div><div>Mehdi</div><div><br class=""></div><br class=""><blockquote type="cite" class=""><div class=""><div dir="ltr" class=""><div class="gmail_extra"><br class=""></div><div class="gmail_extra">I have no theory for bug #2 and I've already spent a day on it.</div></div>
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