[PATCH] D59287: [X86] Only define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_16 in 64-bit mode.

[JF Bastien via Phabricator via cfe-commits]

jfb added a comment.

I don't think this is quite right: CX16 is literally "I have cmpxchg16b".

In clang/lib/Basic/Targets/X86.h we do:

  	  void setMaxAtomicWidth() override {
  	    if (hasFeature("cx16"))
  	      MaxAtomicInlineWidth = 128;
  	  }

Your change makes it inconsistent.

We also have `HasCX16` which should be kept consistent.

The problem seems to be that cx16 can be set for 32-bit targets.


Repository:
  rC Clang

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D59287/new/

https://reviews.llvm.org/D59287