[PATCH 2/2] Only make bloom filter for first parent

[Jonathan Tan]

Signed-off-by: Jonathan Tan <jonathanta...@google.com>
---
 commit-graph.c |  4 ++--
 revision.c     | 20 ++++++++++++--------
 2 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/commit-graph.c b/commit-graph.c
index 90b0b3df90..d21d555611 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -782,9 +782,9 @@ static void fill_bloom_filter(struct bloom_filter *bf,
 
        for (i = 0; i < commit_nr; i++) {
                struct commit *commit = commits[i];
-               struct commit_list *parent;
+               struct commit_list *parent = commit->parents;
 
-               for (parent = commit->parents; parent; parent = parent->next)
+               if (parent)
                        add_changes_to_bloom_filter(bf, parent->item, commit, i,
                                                    &revs.diffopt);
 
diff --git a/revision.c b/revision.c
index c84a997928..5a433a5878 100644
--- a/revision.c
+++ b/revision.c
@@ -539,11 +539,11 @@ static int check_maybe_different_in_bloom_filter(struct 
rev_info *revs,
 }
 
 static int rev_compare_tree(struct rev_info *revs,
-                           struct commit *parent, struct commit *commit)
+                           struct commit *parent, struct commit *commit, int 
nth_parent)
 {
        struct tree *t1 = get_commit_tree(parent);
        struct tree *t2 = get_commit_tree(commit);
-       int bloom_ret;
+       int bloom_ret = 1;
 
        if (!t1)
                return REV_TREE_NEW;
@@ -568,17 +568,21 @@ static int rev_compare_tree(struct rev_info *revs,
                        return REV_TREE_SAME;
        }
 
-       bloom_ret = check_maybe_different_in_bloom_filter(revs, parent, commit);
-       if (bloom_ret == 0)
-               return REV_TREE_SAME;
+       if (!nth_parent) {
+               bloom_ret = check_maybe_different_in_bloom_filter(revs, parent, 
commit);
+               if (bloom_ret == 0)
+                       return REV_TREE_SAME;
+       }
 
        tree_difference = REV_TREE_SAME;
        revs->pruning.flags.has_changes = 0;
        if (diff_tree_oid(&t1->object.oid, &t2->object.oid, "",
                           &revs->pruning) < 0)
                return REV_TREE_DIFFERENT;
-       if (bloom_ret == 1 && tree_difference == REV_TREE_SAME)
-               bloom_filter_count_false_positive++;
+       if (!nth_parent) {
+               if (bloom_ret == 1 && tree_difference == REV_TREE_SAME)
+                       bloom_filter_count_false_positive++;
+       }
        return tree_difference;
 }
 
@@ -776,7 +780,7 @@ static void try_to_simplify_commit(struct rev_info *revs, 
struct commit *commit)
                        die("cannot simplify commit %s (because of %s)",
                            oid_to_hex(&commit->object.oid),
                            oid_to_hex(&p->object.oid));
-               switch (rev_compare_tree(revs, p, commit)) {
+               switch (rev_compare_tree(revs, p, commit, nth_parent)) {
                case REV_TREE_SAME:
                        if (!revs->simplify_history || !relevant_commit(p)) {
                                /* Even if a merge with an uninteresting
-- 
2.19.0.271.gfe8321ec05.dirty