Avoid the use of the OptContext slots.

Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 tcg/optimize.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tcg/optimize.c b/tcg/optimize.c
index 659190dcd8..85e6dcdb26 100644
--- a/tcg/optimize.c
+++ b/tcg/optimize.c
@@ -1868,11 +1868,11 @@ static bool fold_extu(OptContext *ctx, TCGOp *op)
         g_assert_not_reached();
     }
 
-    ctx->z_mask = z_mask;
     if (!type_change && fold_affected_mask(ctx, op, z_mask_old ^ z_mask)) {
         return true;
     }
-    return fold_masks(ctx, op);
+
+    return fold_masks_z(ctx, op, z_mask);
 }
 
 static bool fold_mb(OptContext *ctx, TCGOp *op)
-- 
2.43.0