On Tue, 19 Mar 2019 08:16:00 +0000 George Spelvin <l...@sdf.org> wrote:
> Rather than a fixed-size array of pending sorted runs, use the ->prev > links to keep track of things. This reduces stack usage, eliminates > some ugly overflow handling, and reduces the code size. > > Also: > * merge() no longer needs to handle NULL inputs, so simplify. > * The same applies to merge_and_restore_back_links(), which is renamed > to the less ponderous merge_final(). (It's a static helper function, > so we don't need a super-descriptive name; comments will do.) > * Document the actual return value requirements on the (*cmp)() > function; some callers are already using this feature. > > x86-64 code size 1086 -> 739 bytes (-347) > > (Yes, I see checkpatch complaining about no space after comma in > "__attribute__((nonnull(2,3,4,5)))". Checkpatch is wrong.) x86_64 allnoconfig with gcc-7.3.0: lib/list_sort.c:17:36: warning: __pure__ attribute ignored [-Wattributes] struct list_head const *, struct list_head const *);
