diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index f75d8d04d36..92ee5ea7a64 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2019-06-16  Jozef Lawrynowicz  <jozef.l@mittosystems.com>
+
+	* doc/sourcebuild.texi: Document new effective target keyword
+	longlong64.
+
 2019-06-16  Jan Hubicka  <hubicka@ucw.cz>
 
 	* tree-ssa-alias.c (indirect_ref_may_alias_decl_p,
diff --git a/gcc/doc/sourcebuild.texi b/gcc/doc/sourcebuild.texi
index 546af7f7261..85efadb3ca1 100644
--- a/gcc/doc/sourcebuild.texi
+++ b/gcc/doc/sourcebuild.texi
@@ -1357,6 +1357,9 @@ Target has @code{int} that is at 32 bits or longer.
 @item int16
 Target has @code{int} that is 16 bits or shorter.
 
+@item longlong64
+Target has 64-bit @code{long long}.
+
 @item long_neq_int
 Target has @code{int} and @code{long} with different sizes.
 
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 51861120f8f..2dceffb0399 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2019-06-16  Jozef Lawrynowicz  <jozef.l@mittosystems.com>
+
+	* lib/target-supports.exp: Add check_effective_target_longlong64. 
+
 2019-06-16  Jan Hubicka  <hubicka@ucw.cz>
 
 	* gcc.dg/tree-ssa/alias-access-path-4.c: New testcase.
diff --git a/gcc/testsuite/lib/target-supports.exp b/gcc/testsuite/lib/target-supports.exp
index 01472879062..1d4aaa2a87e 100644
--- a/gcc/testsuite/lib/target-supports.exp
+++ b/gcc/testsuite/lib/target-supports.exp
@@ -2617,6 +2617,15 @@ proc check_effective_target_int32plus { } {
     }]
 }
 
+# Return 1 if we're generating 64-bit long long using default options,
+# 0 otherwise.
+
+proc check_effective_target_longlong64 { } {
+    return [check_no_compiler_messages longlong64 object {
+	int dummy[sizeof (long long) == 8 ? 1 : -1];
+    }]
+}
+
 # Return 1 if we're generating 32-bit or larger pointers using default
 # options, 0 otherwise.