diff --git a/gcc/internal-fn.def b/gcc/internal-fn.def
index a8c83437ada..915d329c05a 100644
--- a/gcc/internal-fn.def
+++ b/gcc/internal-fn.def
@@ -278,6 +278,8 @@ DEF_INTERNAL_SIGNED_OPTAB_FN (MULHRS, ECF_CONST | ECF_NOTHROW, first,
 DEF_INTERNAL_SIGNED_OPTAB_FN (SAT_ADD, ECF_CONST, first, ssadd, usadd, binary)
 DEF_INTERNAL_SIGNED_OPTAB_FN (SAT_SUB, ECF_CONST, first, sssub, ussub, binary)
 
+DEF_INTERNAL_SIGNED_OPTAB_FN (SAT_TRUNC, ECF_CONST, first, sstrunc, ustrunc, unary_convert)
+
 DEF_INTERNAL_COND_FN (ADD, ECF_CONST, add, binary)
 DEF_INTERNAL_COND_FN (SUB, ECF_CONST, sub, binary)
 DEF_INTERNAL_COND_FN (MUL, ECF_CONST, smul, binary)
diff --git a/gcc/match.pd b/gcc/match.pd
index 3d0689c9312..d4062434cc7 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -39,7 +39,8 @@ along with GCC; see the file COPYING3.  If not see
    HONOR_NANS
    uniform_vector_p
    expand_vec_cmp_expr_p
-   bitmask_inv_cst_vector_p)
+   bitmask_inv_cst_vector_p
+   integer_half_truncated_all_ones_p)
 
 /* Operator lists.  */
 (define_operator_list tcc_comparison
@@ -3210,6 +3211,15 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
  (if (INTEGRAL_TYPE_P (type) && TYPE_UNSIGNED (type)
       && types_match (type, @0, @1))))
 
+/* Unsigned saturation truncate, case 1 (), sizeof (WT) > sizeof (NT).
+   SAT_U_TRUNC = (NT)x | (NT)(-(X > (WT)(NT)(-1))).  */
+(match (unsigend_integer_sat_trunc @0)
+ (bit_ior:c (negate (convert (gt @0 integer_half_truncated_all_ones_p)))
+   (convert @0))
+ (if (INTEGRAL_TYPE_P (type) && TYPE_UNSIGNED (type)
+      && TYPE_UNSIGNED (TREE_TYPE (@0))
+      && tree_int_cst_lt (TYPE_SIZE (type), TYPE_SIZE (TREE_TYPE (@0))))))
+
 /* x >  y  &&  x != XXX_MIN  -->  x > y
    x >  y  &&  x == XXX_MIN  -->  false . */
 (for eqne (eq ne)
diff --git a/gcc/optabs.def b/gcc/optabs.def
index bc2611abdc2..4eaffe96c19 100644
--- a/gcc/optabs.def
+++ b/gcc/optabs.def
@@ -63,6 +63,9 @@ OPTAB_CX(fractuns_optab, "fractuns$Q$b$I$a2")
 OPTAB_CL(satfract_optab, "satfract$b$Q$a2", SAT_FRACT, "satfract", gen_satfract_conv_libfunc)
 OPTAB_CL(satfractuns_optab, "satfractuns$I$b$Q$a2", UNSIGNED_SAT_FRACT, "satfractuns", gen_satfractuns_conv_libfunc)
 
+OPTAB_CL(ustrunc_optab, "ustrunc$b$a2", US_TRUNCATE, "ustrunc", gen_satfract_conv_libfunc)
+OPTAB_CL(sstrunc_optab, "sstrunc$b$a2", SS_TRUNCATE, "sstrunc", gen_satfract_conv_libfunc)
+
 OPTAB_CD(sfixtrunc_optab, "fix_trunc$F$b$I$a2")
 OPTAB_CD(ufixtrunc_optab, "fixuns_trunc$F$b$I$a2")
 
diff --git a/gcc/tree-ssa-math-opts.cc b/gcc/tree-ssa-math-opts.cc
index 57085488722..64bc70c29b3 100644
--- a/gcc/tree-ssa-math-opts.cc
+++ b/gcc/tree-ssa-math-opts.cc
@@ -4088,6 +4088,7 @@ arith_overflow_check_p (gimple *stmt, gimple *cast_stmt, gimple *&use_stmt,
 
 extern bool gimple_unsigned_integer_sat_add (tree, tree*, tree (*)(tree));
 extern bool gimple_unsigned_integer_sat_sub (tree, tree*, tree (*)(tree));
+extern bool gimple_unsigend_integer_sat_trunc (tree, tree*, tree (*)(tree));
 
 static void
 build_saturation_binary_arith_call (gimple_stmt_iterator *gsi, internal_fn fn,
@@ -4216,6 +4217,36 @@ match_unsigned_saturation_sub (gimple_stmt_iterator *gsi, gphi *phi)
 					ops[0], ops[1]);
 }
 
+/*
+ * Try to match saturation unsigned sub.
+ * uint16_t x_4(D);
+ * uint8_t _6;
+ * overflow_5 = x_4(D) > 255;
+ * _1 = (unsigned char) x_4(D);
+ * _2 = (unsigned char) overflow_5;
+ * _3 = -_2;
+ * _6 = _1 | _3;
+ * =>
+ * _6 = .SAT_TRUNC (x_4(D));
+ * */
+static void
+match_unsigned_saturation_trunc (gimple_stmt_iterator *gsi, gassign *stmt)
+{
+  tree ops[1];
+  tree lhs = gimple_assign_lhs (stmt);
+  tree type = TREE_TYPE (lhs);
+
+  if (gimple_unsigend_integer_sat_trunc (lhs, ops, NULL)
+    && direct_internal_fn_supported_p (IFN_SAT_TRUNC,
+				       tree_pair (type, TREE_TYPE (ops[0])),
+				       OPTIMIZE_FOR_BOTH))
+    {
+      gcall *call = gimple_build_call_internal (IFN_SAT_TRUNC, 1, ops[0]);
+      gimple_call_set_lhs (call, lhs);
+      gsi_replace (gsi, call, /* update_eh_info */ true);
+    }
+}
+
 /* Recognize for unsigned x
    x = y - z;
    if (x > y)
@@ -6188,6 +6219,7 @@ math_opts_dom_walker::after_dom_children (basic_block bb)
 
 	    case BIT_IOR_EXPR:
 	      match_unsigned_saturation_add (&gsi, as_a<gassign *> (stmt));
+	      match_unsigned_saturation_trunc (&gsi, as_a<gassign *> (stmt));
 	      /* fall-through  */
 	    case BIT_XOR_EXPR:
 	      match_uaddc_usubc (&gsi, stmt, code);
diff --git a/gcc/tree.cc b/gcc/tree.cc
index 2d2d5b6db6e..4572e6fc42b 100644
--- a/gcc/tree.cc
+++ b/gcc/tree.cc
@@ -2944,6 +2944,28 @@ integer_all_onesp (const_tree expr)
 	  == wi::to_wide (expr));
 }
 
+/* Return true if EXPR is an integer constant of all ones with half
+   truncated in precision.  Or return false.  For example:
+   uint16_t a = 255;   // true.
+   uint16_t b = 0;     // false.
+   uint16_t c = 65545; // false.  */
+bool
+integer_half_truncated_all_ones_p (const_tree expr)
+{
+  if (TREE_CODE (expr) != INTEGER_CST)
+    return false;
+
+  unsigned precision = TYPE_PRECISION (TREE_TYPE (expr));
+
+  gcc_assert (precision <= 64);
+
+  unsigned trunc_prec = precision / 2;
+  wide_int trunc_max = wi::uhwi ((uint64_t)-1 >> (64 - trunc_prec), precision);
+  wide_int expr_int = wi::to_wide (expr, precision);
+
+  return trunc_max == expr_int;
+}
+
 /* Return true if EXPR is the integer constant minus one, or a location
    wrapper for such a constant.  */
 
diff --git a/gcc/tree.h b/gcc/tree.h
index 28e8e71b036..0237826dd23 100644
--- a/gcc/tree.h
+++ b/gcc/tree.h
@@ -5205,6 +5205,12 @@ extern bool integer_each_onep (const_tree);
 
 extern bool integer_all_onesp (const_tree);
 
+/* integer_half_truncated_all_ones_p (tree x) will return true if x is
+   the integer constant that the half truncated bits are all 1.
+   For example, uint16_t type with 255 constant integer will be true.  */
+
+extern bool integer_half_truncated_all_ones_p (const_tree expr);
+
 /* integer_minus_onep (tree x) is nonzero if X is an integer constant of
    value -1.  */
 
