r239176 - Revert accidental commit

[David Majnemer]

Author: majnemer
Date: Fri Jun  5 13:24:55 2015
New Revision: 239176

URL: http://llvm.org/viewvc/llvm-project?rev=239176&view=rev
Log:
Revert accidental commit

This change was unrelated to r239170.

Modified:
    cfe/trunk/lib/Headers/Intrin.h

Modified: cfe/trunk/lib/Headers/Intrin.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Headers/Intrin.h?rev=239176&r1=239175&r2=239176&view=diff
==============================================================================
--- cfe/trunk/lib/Headers/Intrin.h (original)
+++ cfe/trunk/lib/Headers/Intrin.h Fri Jun  5 13:24:55 2015
@@ -546,8 +546,13 @@ _bittestandset(long *a, long b) {
 #if defined(__i386__) || defined(__x86_64__)
 static __inline__ unsigned char __attribute__((__always_inline__, __nodebug__))
 _interlockedbittestandset(long volatile *__BitBase, long __BitPos) {
-  long __OldVal = __atomic_fetch_or(__BitBase, 1 << __BitPos, 5);
-  return (__OldVal >> __BitPos) & 1;
+  unsigned char __Res;
+  __asm__ ("xor %0, %0\n"
+           "lock bts %2, %1\n"
+           "setc %0\n"
+           : "=r" (__Res), "+m"(*__BitBase)
+           : "Ir"(__BitPos));
+  return __Res;
 }
 #endif
 #ifdef __x86_64__