diff --git a/openmp/runtime/src/kmp_os.h b/openmp/runtime/src/kmp_os.h
--- a/openmp/runtime/src/kmp_os.h
+++ b/openmp/runtime/src/kmp_os.h
@@ -155,8 +155,8 @@
 typedef unsigned short kmp_uint16;
 typedef int kmp_int32;
 typedef unsigned int kmp_uint32;
-typedef long long kmp_int64;
-typedef unsigned long long kmp_uint64;
+typedef __attribute__((aligned(8))) long long kmp_int64;
+typedef __attribute__((aligned(8))) unsigned long long kmp_uint64;
 #define KMP_INT32_SPEC "d"
 #define KMP_UINT32_SPEC "u"
 #define KMP_INT64_SPEC "lld"