<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><br><div><div>On Nov 15, 2013, at 12:36 PM, Renato Golin <<a href="mailto:renato.golin@linaro.org">renato.golin@linaro.org</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On 15 November 2013 20:24, Joshua Klontz <span dir="ltr"><<a href="mailto:josh.klontz@gmail.com" target="_blank">josh.klontz@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Agreed, is there a pass that will insert a runtime alignment check? Also, what's the easiest way to get at TargetTransformInfo::getRegisterBitWidth() so I don't have to hard code 32? Thanks!</div>
</blockquote><div></div></div><br></div><div class="gmail_extra">I think that's a fair question, and it's about safety. If you're getting this on the JIT, means we may be generating unsafe transformations on the vectorizer.</div>
<div class="gmail_extra"><br></div><div class="gmail_extra">Arnold, Nadav, I don't remember seeing code to generate any run-time alignment checks on the incoming pointer, is there such a thing? If not, shouldn't we add one?</div>
</div></blockquote></div><div><br></div><div><br></div>If the the vectorizer generates aligned memory accesses to unaligned addresses then this is a serious bug. But I don’t think that Josh said that the vectorizer generated aligned accesses to unaligned pointers. <div><br><div><div><div>There is no point in LLVM checking for alignment because if the memory is unaligned then the program will crash. Users who want to crash with a readable error message can simply write code that checks the pointer (by masking the high bits and comparing to zero). <br><br></div></div></div></div></body></html>