ghc-prim: Reduce scope of Clang sync_fetch_and_nand workaround
authorBen Gamari <bgamari.foss@gmail.com>
Thu, 8 Mar 2018 18:22:22 +0000 (13:22 -0500)
committerBen Gamari <ben@smart-cactus.org>
Thu, 8 Mar 2018 21:08:04 +0000 (16:08 -0500)
commited6f9fb9d5a684d2159c29633159c3254cf04deb
tree9fdb2120871ee81643c5f104cbe51fe4d3b19e5c
parentbc95fedc0b1f45b62ba279f7df834c490c2e53b6
ghc-prim: Reduce scope of Clang sync_fetch_and_nand workaround

As described in https://bugs.llvm.org/show_bug.cgi?id=8842, Clang
removed the __sync_fetch_and_nand builtins due to inconsistency in GCC's
behavior in 2010.  However, GCC has since clarified the behavior of
their builtins and consequently Clang re-added them in 2014.
Consequently this workaround should no longer be necessary.

Test Plan: Validate building with Clang

Subscribers: rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4480
libraries/ghc-prim/cbits/atomic.c