Bump the default target CPU for i386-freebsd to i686

[dim]

Summary

Similar to what we have done downstream, some time ago:
https://svnweb.freebsd.org/changeset/base/353936

This followed some discussions on the freebsd-arch mailing lists, and
most people agreed that it was a better default, and also it worked
around several issues where clang generated libcalls to 64 bit atomic
primitives, instead of using cmpxchg8b.

[emaste]

Fine with me

[MaskRay]

@dim

Hi, your git commit contains extra Phabricator tags. You can drop Reviewers: Subscribers: Tags: and the text Summary: from the git commit with the following script:

arcfilter () {
        arc amend
        git log -1 --pretty=%B | awk '/Reviewers:|Subscribers:/{p=1} /Reviewed By:|Differential Revision:/{p=0} !p && !/^Summary:$/ {sub(/^Summary: /,"");print}' | git commit --amend --date=now -F -
}

Reviewed By: is considered important by some people. Please keep the tag. (--date=now is my personal preference (author dates are usually not useful. Using committer dates can make log almost monotonic in time))

llvm/utils/git/pre-push.py can validate the message does not include unneeded tags.

[dim]

In D83645#2160761, @MaskRay wrote:

@dim

Hi, your git commit contains extra Phabricator tags. You can drop Reviewers: Subscribers: Tags: and the text Summary: from the git commit with the following script:

arcfilter () {
        arc amend
        git log -1 --pretty=%B | awk '/Reviewers:|Subscribers:/{p=1} /Reviewed By:|Differential Revision:/{p=0} !p && !/^Summary:$/ {sub(/^Summary: /,"");print}' | git commit --amend --date=now -F -
}

Reviewed By: is considered important by some people. Please keep the tag. (--date=now is my personal preference (author dates are usually not useful. Using committer dates can make log almost monotonic in time))

llvm/utils/git/pre-push.py can validate the message does not include unneeded tags.

Hm, I think I just used arc land to land this revision. Does arc not do all that stuff? In any case, I can't change the commit message after it's been pushed.

[MaskRay]

llvm/utils/git/pre-push.py is recommended for your future commits. I guess arc land is a bad choice because llvm/llvm-project uses the github community version which can't set a pre-receive hook.

clang/lib/Driver/ToolChains/Arch/X86.cpp

if (Triple.isAndroid())
     return Is64Bit ? "x86-64" : "i686";
 
   // Everything else goes to x86-64 in 64-bit mode.
   if (Is64Bit)
     return "x86-64";
 
   switch (Triple.getOS()) {
   case llvm::Triple::FreeBSD:
+    return "i686";
   case llvm::Triple::NetBSD:
   case llvm::Triple::OpenBSD:
     return "i486";
   case llvm::Triple::Haiku:
     return "i586";
   default:
     // Fallback to p4.
     return "pentium4";