diff --git a/diff.c b/diff.c
index 589c1969e4..cfe515af4e 100644
--- a/diff.c
+++ b/diff.c
@@ -3519,29 +3519,6 @@ struct checkdiff_t {
 	int last_line_kind;
 };
 
-static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
-{
-	char firstchar;
-	int cnt;
-
-	if (len < marker_size + 1)
-		return 0;
-	firstchar = line[0];
-	switch (firstchar) {
-	case '=': case '>': case '<': case '|':
-		break;
-	default:
-		return 0;
-	}
-	for (cnt = 1; cnt < marker_size; cnt++)
-		if (line[cnt] != firstchar)
-			return 0;
-	/* line[1] through line[marker_size-1] are same as firstchar */
-	if (len < marker_size + 1 || !isspace(line[marker_size]))
-		return 0;
-	return 1;
-}
-
 static void checkdiff_consume_hunk(void *priv,
 				   long ob UNUSED, long on UNUSED,
 				   long nb, long nn UNUSED,
@@ -3571,7 +3548,7 @@ static int checkdiff_consume(void *priv, char *line, unsigned long len)
 	if (line[0] == '+') {
 		unsigned bad;
 		data->lineno++;
-		if (is_conflict_marker(line + 1, marker_size, len - 1)) {
+		if (is_conflict_marker_line(line + 1, len - 1, marker_size)) {
 			data->status |= 1;
 			fprintf(data->o->file,
 				"%s%s:%d: leftover conflict marker\n",
diff --git a/merge-ll.c b/merge-ll.c
index fafe2c9197..41c97fb90a 100644
--- a/merge-ll.c
+++ b/merge-ll.c
@@ -468,3 +468,34 @@ int ll_merge_marker_size(struct index_state *istate, const char *path)
 	}
 	return marker_size;
 }
+
+int is_conflict_marker_line(const char *line, unsigned long len, int marker_size)
+{
+	char firstchar;
+	int cnt;
+
+	if (len < marker_size + 1)
+		return 0;
+
+	firstchar = line[0];
+	switch (firstchar) {
+	case '=': case '>': case '<': case '|':
+		break;
+	default:
+		return 0;
+	}
+
+	for (cnt = 1; cnt < marker_size; cnt++) {
+		if (line[cnt] != firstchar)
+			return 0;
+	}
+
+	if (((firstchar == '<') || (firstchar == '>')) &&
+	    line[marker_size] != ' ')
+		return 0;
+
+	if (!isspace((unsigned char)line[marker_size]))
+		return 0;
+
+	return firstchar;
+}
diff --git a/merge-ll.h b/merge-ll.h
index d038ee0c1e..b348aee15d 100644
--- a/merge-ll.h
+++ b/merge-ll.h
@@ -109,6 +109,7 @@ enum ll_merge_result ll_merge(mmbuffer_t *result_buf,
 	     const struct ll_merge_options *opts);
 
 int ll_merge_marker_size(struct index_state *istate, const char *path);
+int is_conflict_marker_line(const char *line, unsigned long len, int marker_size);
 void reset_merge_attributes(void);
 
 #endif
diff --git a/rerere.c b/rerere.c
index 216100925a..924a1f2e30 100644
--- a/rerere.c
+++ b/rerere.c
@@ -331,33 +331,6 @@ static int rerere_file_getline(struct strbuf *sb, struct rerere_io *io_)
 	return strbuf_getwholeline(sb, io->input, '\n');
 }
 
-/*
- * Require the exact number of conflict marker letters, no more, no
- * less, followed by SP or any whitespace
- * (including LF).
- */
-static int is_cmarker(char *buf, int marker_char, int marker_size)
-{
-	int want_sp;
-
-	/*
-	 * The beginning of our version and the end of their version
-	 * always are labeled like "<<<<< ours" or ">>>>> theirs",
-	 * hence we set want_sp for them.  Note that the version from
-	 * the common ancestor in diff3-style output is not always
-	 * labelled (e.g. "||||| common" is often seen but "|||||"
-	 * alone is also valid), so we do not set want_sp.
-	 */
-	want_sp = (marker_char == '<') || (marker_char == '>');
-
-	while (marker_size--)
-		if (*buf++ != marker_char)
-			return 0;
-	if (want_sp && *buf != ' ')
-		return 0;
-	return isspace(*buf);
-}
-
 static void rerere_strbuf_putconflict(struct strbuf *buf, int ch, size_t size)
 {
 	strbuf_addchars(buf, ch, size);
@@ -375,7 +348,8 @@ static int handle_conflict(struct strbuf *out, struct rerere_io *io,
 	int has_conflicts = -1;
 
 	while (!io->getline(&buf, io)) {
-		if (is_cmarker(buf.buf, '<', marker_size)) {
+		int marker = is_conflict_marker_line(buf.buf, buf.len, marker_size);
+		if (marker == '<') {
 			if (handle_conflict(&conflict, io, marker_size, NULL) < 0)
 				break;
 			if (hunk == RR_SIDE_1)
@@ -383,15 +357,15 @@ static int handle_conflict(struct strbuf *out, struct rerere_io *io,
 			else
 				strbuf_addbuf(&two, &conflict);
 			strbuf_release(&conflict);
-		} else if (is_cmarker(buf.buf, '|', marker_size)) {
+		} else if (marker == '|') {
 			if (hunk != RR_SIDE_1)
 				break;
 			hunk = RR_ORIGINAL;
-		} else if (is_cmarker(buf.buf, '=', marker_size)) {
+		} else if (marker == '=') {
 			if (hunk != RR_SIDE_1 && hunk != RR_ORIGINAL)
 				break;
 			hunk = RR_SIDE_2;
-		} else if (is_cmarker(buf.buf, '>', marker_size)) {
+		} else if (marker == '>') {
 			if (hunk != RR_SIDE_2)
 				break;
 			if (strbuf_cmp(&one, &two) > 0)
@@ -442,7 +416,7 @@ static int handle_path(unsigned char *hash, struct rerere_io *io, int marker_siz
 		git_hash_init(&ctx, the_hash_algo);
 
 	while (!io->getline(&buf, io)) {
-		if (is_cmarker(buf.buf, '<', marker_size)) {
+		if (is_conflict_marker_line(buf.buf, buf.len, marker_size) == '<') {
 			has_conflicts = handle_conflict(&out, io, marker_size,
 							hash ? &ctx : NULL);
 			if (has_conflicts < 0)