diff --git a/gcc/internal-fn.cc b/gcc/internal-fn.cc
index a07f25f3aee..aaf9f8991b3 100644
--- a/gcc/internal-fn.cc
+++ b/gcc/internal-fn.cc
@@ -4103,6 +4103,17 @@ direct_internal_fn_supported_p (internal_fn fn, tree_pair types,
 	return direct_##TYPE##_optab_supported_p (which_optab, types,	\
 						  opt_type);		\
       }
+#define DEF_INTERNAL_SIGNED_OPTAB_EXT_FN(CODE, FLAGS, SELECTOR, SIGNED_OPTAB, \
+					 UNSIGNED_OPTAB, TYPE)		\
+    case IFN_##CODE:							\
+      {									\
+	optab which_optab = (TYPE_UNSIGNED (types.SELECTOR)		\
+			     ? UNSIGNED_OPTAB ## _optab			\
+			     : SIGNED_OPTAB ## _optab);			\
+	return direct_##TYPE##_optab_supported_p (which_optab, types,	\
+						  opt_type)		\
+	       || internal_##CODE##_fn_supported_p (types.SELECTOR, opt_type); \
+      }
 #include "internal-fn.def"
 
     case IFN_LAST:
@@ -4303,6 +4314,8 @@ set_edom_supported_p (void)
     optab which_optab = direct_internal_fn_optab (fn, types);		\
     expand_##TYPE##_optab_fn (fn, stmt, which_optab);			\
   }
+#define DEF_INTERNAL_SIGNED_OPTAB_EXT_FN(CODE, FLAGS, SELECTOR, SIGNED_OPTAB, \
+					 UNSIGNED_OPTAB, TYPE)
 #include "internal-fn.def"
 
 /* Routines to expand each internal function, indexed by function number.
@@ -5177,3 +5190,45 @@ expand_POPCOUNT (internal_fn fn, gcall *stmt)
       emit_move_insn (plhs, cmp);
     }
 }
+
+void
+expand_SAT_ADD (internal_fn fn, gcall *stmt)
+{
+  /* Check if the target supports the expansion through an IFN.  */
+  tree_pair types = direct_internal_fn_types (fn, stmt);
+  optab which_optab = direct_internal_fn_optab (fn, types);
+  if (direct_binary_optab_supported_p (which_optab, types,
+				       insn_optimization_type ()))
+    {
+      expand_binary_optab_fn (fn, stmt, which_optab);
+      return;
+    }
+
+  /* Target does not support the optab, but we can de-compose it.  */
+  /*
+  ... decompose to a canonical representation ...
+  if (TYPE_UNSIGNED (types.SELECTOR))
+    {
+      ...
+      decompose back to (X + Y) | - ((X + Y) < X)
+    }
+  else
+    {
+      ...
+    }
+  */
+}
+
+bool internal_SAT_ADD_fn_supported_p (tree type, optimization_type /* optype */)
+{
+  /* For now, don't support decomposing vector ops.  */
+  if (VECTOR_TYPE_P (type))
+    return false;
+
+  /* Signed saturating arithmetic is harder to do since we'll so for now
+     lets ignore.  */
+  if (!TYPE_UNSIGNED (type))
+    return false;
+
+  return TREE_CODE (type) == INTEGER_TYPE;
+}
\ No newline at end of file
diff --git a/gcc/internal-fn.def b/gcc/internal-fn.def
index c14d30365c1..5a2491228d5 100644
--- a/gcc/internal-fn.def
+++ b/gcc/internal-fn.def
@@ -92,6 +92,10 @@ along with GCC; see the file COPYING3.  If not see
    unsigned inputs respectively, both without the trailing "_optab".
    SELECTOR says which type in the tree_pair determines the signedness.
 
+   DEF_INTERNAL_SIGNED_OPTAB_EXT_FN is like DEF_INTERNAL_SIGNED_OPTAB_FN, except
+   that it has expand_##NAME defined in internal-fn.cc to override the
+   DEF_INTERNAL_SIGNED_OPTAB_FN expansion behavior.
+
    DEF_INTERNAL_FLT_FN is like DEF_INTERNAL_OPTAB_FN, but in addition,
    the function implements the computational part of a built-in math
    function BUILT_IN_<NAME>{F,,L}.  Unlike some built-in functions,
@@ -153,6 +157,13 @@ along with GCC; see the file COPYING3.  If not see
   DEF_INTERNAL_FN (NAME, FLAGS | ECF_LEAF, NULL)
 #endif
 
+#ifndef DEF_INTERNAL_SIGNED_OPTAB_EXT_FN
+#define DEF_INTERNAL_SIGNED_OPTAB_EXT_FN(NAME, FLAGS, SELECTOR, SIGNED_OPTAB, \
+				     UNSIGNED_OPTAB, TYPE) \
+  DEF_INTERNAL_SIGNED_OPTAB_FN (NAME, FLAGS, SELECTOR, SIGNED_OPTAB, \
+				UNSIGNED_OPTAB, TYPE)
+#endif
+
 #ifndef DEF_INTERNAL_FLT_FN
 #define DEF_INTERNAL_FLT_FN(NAME, FLAGS, OPTAB, TYPE) \
   DEF_INTERNAL_OPTAB_FN (NAME, FLAGS, OPTAB, TYPE)
@@ -274,6 +285,8 @@ DEF_INTERNAL_SIGNED_OPTAB_FN (MULHS, ECF_CONST | ECF_NOTHROW, first,
 			      smulhs, umulhs, binary)
 DEF_INTERNAL_SIGNED_OPTAB_FN (MULHRS, ECF_CONST | ECF_NOTHROW, first,
 			      smulhrs, umulhrs, binary)
+DEF_INTERNAL_SIGNED_OPTAB_EXT_FN (SAT_ADD, ECF_CONST | ECF_NOTHROW, first,
+				  ssadd, usadd, binary)
 
 DEF_INTERNAL_COND_FN (ADD, ECF_CONST, add, binary)
 DEF_INTERNAL_COND_FN (SUB, ECF_CONST, sub, binary)
@@ -593,5 +606,6 @@ DEF_INTERNAL_FN (BITINTTOFLOAT, ECF_PURE | ECF_LEAF, ". R . ")
 #undef DEF_INTERNAL_FLT_FN
 #undef DEF_INTERNAL_FLT_FLOATN_FN
 #undef DEF_INTERNAL_SIGNED_OPTAB_FN
+#undef DEF_INTERNAL_SIGNED_OPTAB_EXT_FN
 #undef DEF_INTERNAL_OPTAB_FN
 #undef DEF_INTERNAL_FN
diff --git a/gcc/internal-fn.h b/gcc/internal-fn.h
index bccee1c3e09..dbdb1e6bad2 100644
--- a/gcc/internal-fn.h
+++ b/gcc/internal-fn.h
@@ -263,6 +263,8 @@ extern void expand_DIVMODBITINT (internal_fn, gcall *);
 extern void expand_FLOATTOBITINT (internal_fn, gcall *);
 extern void expand_BITINTTOFLOAT (internal_fn, gcall *);
 extern void expand_POPCOUNT (internal_fn, gcall *);
+extern void expand_SAT_ADD (internal_fn, gcall *);
+extern bool internal_SAT_ADD_fn_supported_p (tree, optimization_type);
 
 extern bool vectorized_internal_fn_supported_p (internal_fn, tree);