<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=""><div><blockquote type="cite" class=""><div class="">On Jun 1, 2016, at 1:11 PM, Eric Christopher via cfe-dev <<a href="mailto:cfe-dev@lists.llvm.org" class="">cfe-dev@lists.llvm.org</a>> wrote:</div><div class=""><div dir="ltr" class=""><div class="gmail_quote"><div dir="ltr" class="">On Wed, Jun 1, 2016 at 8:37 AM C Bergström <<a href="mailto:cfe-dev@lists.llvm.org" class="">cfe-dev@lists.llvm.org</a>> wrote:<br class=""></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">On Wed, Jun 1, 2016 at 11:26 PM, Reid Kleckner <<a href="mailto:rnk@google.com" target="_blank" class="">rnk@google.com</a>> wrote:<br class="">
> Clang has never exposed the same set of builtins as GCC, though:<br class="">
> <a href="http://clang.llvm.org/compatibility.html#vector_builtins" rel="noreferrer" target="_blank" class="">http://clang.llvm.org/compatibility.html#vector_builtins</a><br class="">
><br class="">
> I don't think we need to keep our IA32 vector builtin interface stable when<br class="">
> the *mmintrin.h headers already provide a stable, portable, cross-vendor<br class="">
> interface to the same functionality.<br class="">
<br class="">
I didn't mention gcc.. I agree they shouldn't be used in the wild, but<br class="">
they are..<br class="">
<br class="">
Why not leave the built-in support and under the hood just map that to<br class="">
something more portable? This is a pretty low cost (zero?) maintenance<br class="">
burden...<br class="">
<br class="">
Intentionally breaking stuff without at least giving any warning or<br class="">
marking as deprecated in a major release 1st.. Is this an exception<br class="">
because __built-ins are grey area support?<br class=""><br class=""></blockquote><div class=""><br class=""></div><div class="">What Reid is saying has been our policy from the beginning, there's even a script in the repository (that I sadly haven't updated in years) that helps handle the transition between builtins and the *mmintrin.h headers.</div></div></div></div></blockquote><div><br class=""></div>I agree that we don't need to support undocumented builtins.</div><div><br class=""></div><div>John.</div></body></html>