diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c
index 4f0652f553e..869f0d11b2e 100644
--- a/gcc/simplify-rtx.c
+++ b/gcc/simplify-rtx.c
@@ -1527,6 +1527,38 @@ simplify_unary_operation_1 (enum rtx_code code, machine_mode mode, rtx op)
 	  && XEXP (op, 1) != const0_rtx)
 	return simplify_gen_unary (ZERO_EXTEND, mode, op, GET_MODE (op));
 
+      /* (sign_extend:M (truncate:N (lshiftrt:O <X> (const_int I)))) where
+	 I is GET_MODE_PRECISION(O) - GET_MODE_PRECISION(N), simplifies to
+	 (ashiftrt:M <X> (const_int I)) if modes M and O are the same, and
+	 (truncate:M (ashiftrt:O <X> (const_int I))) if M is narrower than
+	 O, and (sign_extend:M (ashiftrt:O <X> (const_int I))) if M is
+	 wider than O.  */
+      if (GET_CODE (op) == TRUNCATE
+	  && GET_CODE (XEXP (op, 0)) == LSHIFTRT
+	  && CONST_INT_P (XEXP (XEXP (op, 0), 1)))
+	{
+	  scalar_int_mode m_mode, n_mode, o_mode;
+	  rtx old_shift = XEXP (op, 0);
+	  if (is_a <scalar_int_mode> (mode, &m_mode)
+	      && is_a <scalar_int_mode> (GET_MODE (op), &n_mode)
+	      && is_a <scalar_int_mode> (GET_MODE (old_shift), &o_mode)
+	      && GET_MODE_PRECISION (o_mode) - GET_MODE_PRECISION (n_mode)
+		 == INTVAL (XEXP (old_shift, 1)))
+	    {
+	      rtx new_shift = simplify_gen_binary (ASHIFTRT,
+						   GET_MODE (old_shift),
+						   XEXP (old_shift, 0),
+						   XEXP (old_shift, 1));
+	      if (GET_MODE_PRECISION (m_mode) > GET_MODE_PRECISION (o_mode))
+		return simplify_gen_unary (SIGN_EXTEND, mode, new_shift,
+					   GET_MODE (new_shift));
+	      if (mode != GET_MODE (new_shift))
+		return simplify_gen_unary (TRUNCATE, mode, new_shift,
+					   GET_MODE (new_shift));
+	      return new_shift;
+	    }
+	}
+
 #if defined(POINTERS_EXTEND_UNSIGNED)
       /* As we do not know which address space the pointer is referring to,
 	 we can do this only if the target does not support different pointer