Revert accidental commit

This change was unrelated to r239170.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@239176 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Headers/Intrin.h b/lib/Headers/Intrin.h
index 9592cccb15c72bde18cc6e6dc3ff615ca5186d73..727a55e5b7619c83616e4e2a623cc156cba3c8fa 100644 (file)
--- a/lib/Headers/Intrin.h
+++ b/lib/Headers/Intrin.h
@@ -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__