Index: include/llvm/Support/Threading.h
===================================================================
--- include/llvm/Support/Threading.h
+++ include/llvm/Support/Threading.h
@@ -27,7 +27,9 @@
 #define LLVM_THREADING_USE_STD_CALL_ONCE 1
 #elif defined(LLVM_ON_UNIX) &&                                                 \
     (defined(_LIBCPP_VERSION) ||                                               \
-     !(defined(__NetBSD__) || defined(__OpenBSD__) || defined(__ppc__)))
+     !(defined(__NetBSD__) || defined(__OpenBSD__) ||                          \
+       (defined(__ppc__) || defined(__PPC__))) ||                              \
+       (defined(__PPC__) && defined(__LITTLE_ENDIAN__)))
 // std::call_once from libc++ is used on all Unix platforms. Other
 // implementations like libstdc++ are known to have problems on NetBSD,
 // OpenBSD and PowerPC.