Go patch committed: Define __atomic_fetch_add functions

[Ian Lance Taylor via Gcc-patches]

This patch to the GCC-specific part of the Go frontend defines the
__atomic_fetch_add functions.  The frontend only generates calls to
the __atomic_add_fetch functions, but in some cases the middle-end can
transform the latter into the former.  This patch is originally by
Marc Poulhiès.  This fixes PR  107581.  Bootstrapped and ran Go
testsuite on x86_64-pc-linux-gnu.  Committed to mainline.

Ian

diff --git a/gcc/go/go-gcc.cc b/gcc/go/go-gcc.cc
index 1ba7206caeb..6e5887aecab 100644
--- a/gcc/go/go-gcc.cc
+++ b/gcc/go/go-gcc.cc
@@ -886,16 +886,20 @@ Gcc_backend::Gcc_backend()
                                uint32_type_node,
                                integer_type_node,
                                NULL_TREE);
-  this->define_builtin(BUILT_IN_ATOMIC_ADD_FETCH_4, "__atomic_add_fetch_4", 
NULL,
-                       t, 0);
+  this->define_builtin(BUILT_IN_ATOMIC_ADD_FETCH_4, "__atomic_add_fetch_4",
+                      NULL, t, 0);
+  this->define_builtin(BUILT_IN_ATOMIC_FETCH_ADD_4, "__atomic_fetch_add_4",
+                      NULL, t, 0);
 
   t = build_function_type_list(uint64_type_node,
                                ptr_type_node,
                                uint64_type_node,
                                integer_type_node,
                                NULL_TREE);
-  this->define_builtin(BUILT_IN_ATOMIC_ADD_FETCH_8, "__atomic_add_fetch_8", 
NULL,
-                       t, 0);
+  this->define_builtin(BUILT_IN_ATOMIC_ADD_FETCH_8, "__atomic_add_fetch_8",
+                      NULL, t, 0);
+  this->define_builtin(BUILT_IN_ATOMIC_FETCH_ADD_8, "__atomic_fetch_add_8",
+                      NULL, t, 0);
 
   t = build_function_type_list(unsigned_char_type_node,
                               ptr_type_node,