commit 5f6a983e7fba98335e2863fe31305e895545ebb2
Author: dim <dim@FreeBSD.org>
Date:   Sun Sep 8 10:31:34 2019 +0000

    Target i586 by default on the i386 architecture, since after upstream's
    change https://reviews.llvm.org/rL356631 ("[X86] Add CMPXCHG8B feature
    flag. Set it for all CPUs except i386/i486 including 'generic'. Disable
    use of CMPXCHG8B when this flag isn't set"), clang now correctly emits
    calls to __atomic_load_8, __atomic_store_8, etc. when targeting i486,
    and this means we can no longer link most modern programs, because we do
    not have a libatomic, nor support for atomic functions in libc.  See
    also PR 230888, 220822, 233725, 234976, and more probably duplicates.
    
    Note that in practice, clang has been incorrectly generating cmpxchg8b
    instructions for years now, when targeting i486.  So de facto nothing
    really changes by doing this.

Notes:
    svn path=/projects/clang900-import/; revision=352030

diff --git tools/clang/lib/Driver/ToolChains/Arch/X86.cpp tools/clang/lib/Driver/ToolChains/Arch/X86.cpp
index 34be226b69e9..9a5c0aa28c7f 100644
--- tools/clang/lib/Driver/ToolChains/Arch/X86.cpp
+++ tools/clang/lib/Driver/ToolChains/Arch/X86.cpp
@@ -93,10 +93,10 @@ const char *x86::getX86TargetCPU(const ArgList &Args,
     return "x86-64";
 
   switch (Triple.getOS()) {
-  case llvm::Triple::FreeBSD:
   case llvm::Triple::NetBSD:
   case llvm::Triple::OpenBSD:
     return "i486";
+  case llvm::Triple::FreeBSD:
   case llvm::Triple::Haiku:
     return "i586";
   default: