revset-_ancestor: use & instead of filter The & operation is more likely optimised. ::10 before) wall 0.028189 comb 0.030000 user 0.030000 sys 0.000000 (best of 100) after) wall 0.001050 comb 0.000000 user 0.000000 sys 0.000000 (best of 2326) ::tip before) wall 0.081132 comb 0.080000 user 0.080000 sys 0.000000 (best of 100) after) wall 0.055418 comb 0.050000 user 0.050000 sys 0.000000 (best of 100)