tcg: Fix expansion of INDEX_op_not_vec

This operation can always be emitted, even if we need to
fall back to xor.  Adjust the assertions to match.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

tcg/tcg-op-vec.c

@@ -90,6 +90,9 @@ bool tcg_can_emit_vecop_list(const TCGOpcode *list,
         case INDEX_op_bitsel_vec:
             /* These opcodes are mandatory and should not be listed.  */
             g_assert_not_reached();
+        case INDEX_op_not_vec:
+            /* These opcodes have generic expansions using the above.  */
+            g_assert_not_reached();
         default:
             break;
         }
@@ -438,11 +441,14 @@ static bool do_op2(unsigned vece, TCGv_vec r, TCGv_vec a, TCGOpcode opc)
 
 void tcg_gen_not_vec(unsigned vece, TCGv_vec r, TCGv_vec a)
 {
+    const TCGOpcode *hold_list = tcg_swap_vecop_list(NULL);
+
     if (!TCG_TARGET_HAS_not_vec || !do_op2(vece, r, a, INDEX_op_not_vec)) {
         TCGv_vec t = tcg_const_ones_vec_matching(r);
         tcg_gen_xor_vec(0, r, a, t);
         tcg_temp_free_vec(t);
     }
+    tcg_swap_vecop_list(hold_list);
 }
 
 void tcg_gen_neg_vec(unsigned vece, TCGv_vec r, TCGv_vec a)