diff --git a/builtin/log.c b/builtin/log.c
index 734aab3a73..39181e239f 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -795,7 +795,7 @@ static int reopen_stdout(struct commit *commit, const char *subject,
 static void get_patch_ids(struct rev_info *rev, struct patch_ids *ids)
 {
 	struct rev_info check_rev;
-	struct commit *commit;
+	struct commit *commit, *c1, *c2;
 	struct object *o1, *o2;
 	unsigned flags1, flags2;
 
@@ -803,9 +803,11 @@ static void get_patch_ids(struct rev_info *rev, struct patch_ids *ids)
 		die(_("Need exactly one range."));
 
 	o1 = rev->pending.objects[0].item;
-	flags1 = o1->flags;
 	o2 = rev->pending.objects[1].item;
+	flags1 = o1->flags;
 	flags2 = o2->flags;
+	c1 = lookup_commit_reference(o1->sha1);
+	c2 = lookup_commit_reference(o2->sha1);
 
 	if ((flags1 & UNINTERESTING) == (flags2 & UNINTERESTING))
 		die(_("Not a range."));
@@ -827,10 +829,8 @@ static void get_patch_ids(struct rev_info *rev, struct patch_ids *ids)
 	}
 
 	/* reset for next revision walk */
-	clear_commit_marks((struct commit *)o1,
-			SEEN | UNINTERESTING | SHOWN | ADDED);
-	clear_commit_marks((struct commit *)o2,
-			SEEN | UNINTERESTING | SHOWN | ADDED);
+	clear_commit_marks(c1, SEEN | UNINTERESTING | SHOWN | ADDED);
+	clear_commit_marks(c2, SEEN | UNINTERESTING | SHOWN | ADDED);
 	o1->flags = flags1;
 	o2->flags = flags2;
 }
diff --git a/t/t4014-format-patch.sh b/t/t4014-format-patch.sh
index 256affce89..2ea12dd088 100755
--- a/t/t4014-format-patch.sh
+++ b/t/t4014-format-patch.sh
@@ -57,6 +57,14 @@ test_expect_success "format-patch --ignore-if-in-upstream" '
 
 '
 
+test_expect_success "format-patch --ignore-if-in-upstream handles tags" '
+	git tag -a v1 -m tag side &&
+	git tag -a v2 -m tag master &&
+	git format-patch --stdout --ignore-if-in-upstream v2..v1 >patch1 &&
+	cnt=$(grep "^From " patch1 | wc -l) &&
+	test $cnt = 2
+'
+
 test_expect_success "format-patch doesn't consider merge commits" '
 
 	git checkout -b slave master &&