diff --git a/tcg/optimize.c b/tcg/optimize.c
index 5fa4d7285d..c0eccc61d6 100644
--- a/tcg/optimize.c
+++ b/tcg/optimize.c
@@ -1229,7 +1229,7 @@ static bool fold_count_zeros(OptContext *ctx, TCGOp *op)
         g_assert_not_reached();
     }
     ctx->z_mask = arg_info(op->args[2])->z_mask | z_mask;
-
+    ctx->s_mask = smask_from_zmask(ctx->z_mask);
     return false;
 }
 
@@ -1249,6 +1249,7 @@ static bool fold_ctpop(OptContext *ctx, TCGOp *op)
     default:
         g_assert_not_reached();
     }
+    ctx->s_mask = smask_from_zmask(ctx->z_mask);
     return false;
 }