[PATCH 3.16.y-ckt 108/185] ARC: add compiler barrier to LLSC based cmpxchg

3.16.7-ckt15 -stable review patch. If anyone has any objections, please let me know. -- From: Vineet Gupta commit d57f727264f1425a94689bafc7e99e502cb135b5 upstream. When auditing cmpxchg call sites, Chuck noted that gcc was optimizing away some of the desired LDs. |

[PATCH 3.16.y-ckt 108/185] ARC: add compiler barrier to LLSC based cmpxchg

3.16.7-ckt15 -stable review patch. If anyone has any objections, please let me know. -- From: Vineet Gupta vgu...@synopsys.com commit d57f727264f1425a94689bafc7e99e502cb135b5 upstream. When auditing cmpxchg call sites, Chuck noted that gcc was optimizing away some of the