diff --git a/gcc/match.pd b/gcc/match.pd
index 5ec31ef6269..ba83f0f29e6 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -3374,6 +3374,20 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
 	@2)
  (if (INTEGRAL_TYPE_P (type) && !TYPE_UNSIGNED (type))))
 
+/* Signed saturation sub, case 2:
+   T minus = (T)((UT)X - (UT)Y);
+   SAT_S_SUB = (X ^ Y) & (X ^ minus) < 0 ? (-(T)(X < 0) ^ MAX) : minus;
+
+   The T and UT are type pair like T=int8_t, UT=uint8_t.  */
+(match (signed_integer_sat_sub @0 @1)
+ (cond^ (ge (bit_and:c (bit_xor:c @0 @1)
+		       (bit_xor @0 (nop_convert@2 (minus (nop_convert @0)
+							 (nop_convert @1)))))
+	    integer_zerop)
+	@2
+	(bit_xor:c (negate (convert (lt @0 integer_zerop))) max_value))
+ (if (INTEGRAL_TYPE_P (type) && !TYPE_UNSIGNED (type))))
+
 /* Unsigned saturation truncate, case 1, sizeof (WT) > sizeof (NT).
    SAT_U_TRUNC = (NT)x | (NT)(-(X > (WT)(NT)(-1))).  */
 (match (unsigned_integer_sat_trunc @0)