diff --git a/builtin/commit.c b/builtin/commit.c
index d75b3805ea..960e7ac081 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -912,11 +912,12 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 			 * submodules which were manually staged, which would
 			 * be really confusing.
 			 */
-			int diff_flags = DIFF_OPT_OVERRIDE_SUBMODULE_CONFIG;
+			struct diff_flags flags = DIFF_FLAGS_INIT;
+			flags.OVERRIDE_SUBMODULE_CONFIG = 1;
 			if (ignore_submodule_arg &&
 			    !strcmp(ignore_submodule_arg, "all"))
-				diff_flags |= DIFF_OPT_IGNORE_SUBMODULES;
-			commitable = index_differs_from(parent, diff_flags, 1);
+				flags.IGNORE_SUBMODULES = 1;
+			commitable = index_differs_from(parent, &flags, 1);
 		}
 	}
 	strbuf_release(&committer_ident);
diff --git a/builtin/log.c b/builtin/log.c
index d81a09051e..dc28d43eb7 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -134,7 +134,8 @@ static void cmd_log_init_defaults(struct rev_info *rev)
 
 	if (default_date_mode)
 		parse_date_format(default_date_mode, &rev->date_mode);
-	rev->diffopt.touched_flags = 0;
+
+	memset(&rev->diffopt.touched_flags, 0, sizeof(struct diff_flags));
 }
 
 static void cmd_log_init_finish(int argc, const char **argv, const char *prefix,
diff --git a/diff-lib.c b/diff-lib.c
index 4e0980caa8..ed37f24c68 100644
--- a/diff-lib.c
+++ b/diff-lib.c
@@ -71,7 +71,7 @@ static int match_stat_with_submodule(struct diff_options *diffopt,
 {
 	int changed = ce_match_stat(ce, st, ce_option);
 	if (S_ISGITLINK(ce->ce_mode)) {
-		unsigned orig_flags = diffopt->flags;
+		struct diff_flags orig_flags = diffopt->flags;
 		if (!DIFF_OPT_TST(diffopt, OVERRIDE_SUBMODULE_CONFIG))
 			set_diffopt_flags_from_submodule_config(diffopt, ce->name);
 		if (DIFF_OPT_TST(diffopt, IGNORE_SUBMODULES))
@@ -534,7 +534,7 @@ int do_diff_cache(const struct object_id *tree_oid, struct diff_options *opt)
 	return 0;
 }
 
-int index_differs_from(const char *def, int diff_flags,
+int index_differs_from(const char *def, const struct diff_flags *flags,
 		       int ita_invisible_in_index)
 {
 	struct rev_info rev;
@@ -546,7 +546,8 @@ int index_differs_from(const char *def, int diff_flags,
 	setup_revisions(0, NULL, &rev, &opt);
 	DIFF_OPT_SET(&rev.diffopt, QUICK);
 	DIFF_OPT_SET(&rev.diffopt, EXIT_WITH_STATUS);
-	rev.diffopt.flags |= diff_flags;
+	if (flags)
+		diff_flags_or(&rev.diffopt.flags, flags);
 	rev.diffopt.ita_invisible_in_index = ita_invisible_in_index;
 	run_diff_index(&rev, 1);
 	object_array_clear(&rev.pending);
diff --git a/diff.c b/diff.c
index 6fd288420b..3ad9c9b31c 100644
--- a/diff.c
+++ b/diff.c
@@ -5899,7 +5899,7 @@ int diff_can_quit_early(struct diff_options *opt)
 static int is_submodule_ignored(const char *path, struct diff_options *options)
 {
 	int ignored = 0;
-	unsigned orig_flags = options->flags;
+	struct diff_flags orig_flags = options->flags;
 	if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
 		set_diffopt_flags_from_submodule_config(options, path);
 	if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
diff --git a/diff.h b/diff.h
index aca150ba2e..e512cf44d0 100644
--- a/diff.h
+++ b/diff.h
@@ -60,42 +60,56 @@ typedef struct strbuf *(*diff_prefix_fn_t)(struct diff_options *opt, void *data)
 
 #define DIFF_FORMAT_CALLBACK	0x1000
 
-#define DIFF_OPT_RECURSIVE           (1 <<  0)
-#define DIFF_OPT_TREE_IN_RECURSIVE   (1 <<  1)
-#define DIFF_OPT_BINARY              (1 <<  2)
-#define DIFF_OPT_TEXT                (1 <<  3)
-#define DIFF_OPT_FULL_INDEX          (1 <<  4)
-#define DIFF_OPT_SILENT_ON_REMOVE    (1 <<  5)
-#define DIFF_OPT_FIND_COPIES_HARDER  (1 <<  6)
-#define DIFF_OPT_FOLLOW_RENAMES      (1 <<  7)
-#define DIFF_OPT_RENAME_EMPTY        (1 <<  8)
-/* (1 <<  9) unused */
-#define DIFF_OPT_HAS_CHANGES         (1 << 10)
-#define DIFF_OPT_QUICK               (1 << 11)
-#define DIFF_OPT_NO_INDEX            (1 << 12)
-#define DIFF_OPT_ALLOW_EXTERNAL      (1 << 13)
-#define DIFF_OPT_EXIT_WITH_STATUS    (1 << 14)
-#define DIFF_OPT_REVERSE_DIFF        (1 << 15)
-#define DIFF_OPT_CHECK_FAILED        (1 << 16)
-#define DIFF_OPT_RELATIVE_NAME       (1 << 17)
-#define DIFF_OPT_IGNORE_SUBMODULES   (1 << 18)
-#define DIFF_OPT_DIRSTAT_CUMULATIVE  (1 << 19)
-#define DIFF_OPT_DIRSTAT_BY_FILE     (1 << 20)
-#define DIFF_OPT_ALLOW_TEXTCONV      (1 << 21)
-#define DIFF_OPT_DIFF_FROM_CONTENTS  (1 << 22)
-#define DIFF_OPT_DIRTY_SUBMODULES    (1 << 24)
-#define DIFF_OPT_IGNORE_UNTRACKED_IN_SUBMODULES (1 << 25)
-#define DIFF_OPT_IGNORE_DIRTY_SUBMODULES (1 << 26)
-#define DIFF_OPT_OVERRIDE_SUBMODULE_CONFIG (1 << 27)
-#define DIFF_OPT_DIRSTAT_BY_LINE     (1 << 28)
-#define DIFF_OPT_FUNCCONTEXT         (1 << 29)
-#define DIFF_OPT_PICKAXE_IGNORE_CASE (1 << 30)
-#define DIFF_OPT_DEFAULT_FOLLOW_RENAMES (1U << 31)
-
-#define DIFF_OPT_TST(opts, flag)    ((opts)->flags & DIFF_OPT_##flag)
-#define DIFF_OPT_TOUCHED(opts, flag)    ((opts)->touched_flags & DIFF_OPT_##flag)
-#define DIFF_OPT_SET(opts, flag)    (((opts)->flags |= DIFF_OPT_##flag),((opts)->touched_flags |= DIFF_OPT_##flag))
-#define DIFF_OPT_CLR(opts, flag)    (((opts)->flags &= ~DIFF_OPT_##flag),((opts)->touched_flags |= DIFF_OPT_##flag))
+#define DIFF_FLAGS_INIT { 0 }
+struct diff_flags {
+	unsigned RECURSIVE:1;
+	unsigned TREE_IN_RECURSIVE:1;
+	unsigned BINARY:1;
+	unsigned TEXT:1;
+	unsigned FULL_INDEX:1;
+	unsigned SILENT_ON_REMOVE:1;
+	unsigned FIND_COPIES_HARDER:1;
+	unsigned FOLLOW_RENAMES:1;
+	unsigned RENAME_EMPTY:1;
+	unsigned HAS_CHANGES:1;
+	unsigned QUICK:1;
+	unsigned NO_INDEX:1;
+	unsigned ALLOW_EXTERNAL:1;
+	unsigned EXIT_WITH_STATUS:1;
+	unsigned REVERSE_DIFF:1;
+	unsigned CHECK_FAILED:1;
+	unsigned RELATIVE_NAME:1;
+	unsigned IGNORE_SUBMODULES:1;
+	unsigned DIRSTAT_CUMULATIVE:1;
+	unsigned DIRSTAT_BY_FILE:1;
+	unsigned ALLOW_TEXTCONV:1;
+	unsigned DIFF_FROM_CONTENTS:1;
+	unsigned DIRTY_SUBMODULES:1;
+	unsigned IGNORE_UNTRACKED_IN_SUBMODULES:1;
+	unsigned IGNORE_DIRTY_SUBMODULES:1;
+	unsigned OVERRIDE_SUBMODULE_CONFIG:1;
+	unsigned DIRSTAT_BY_LINE:1;
+	unsigned FUNCCONTEXT:1;
+	unsigned PICKAXE_IGNORE_CASE:1;
+	unsigned DEFAULT_FOLLOW_RENAMES:1;
+};
+
+static inline void diff_flags_or(struct diff_flags *a,
+				 const struct diff_flags *b)
+{
+	char *tmp_a = (char *)a;
+	const char *tmp_b = (const char *)b;
+	int i;
+
+	for (i = 0; i < sizeof(struct diff_flags); i++)
+		tmp_a[i] |= tmp_b[i];
+}
+
+#define DIFF_OPT_TST(opts, flag)	((opts)->flags.flag)
+#define DIFF_OPT_TOUCHED(opts, flag)	((opts)->touched_flags.flag)
+#define DIFF_OPT_SET(opts, flag)	(((opts)->flags.flag = 1),((opts)->touched_flags.flag = 1))
+#define DIFF_OPT_CLR(opts, flag)	(((opts)->flags.flag = 0),((opts)->touched_flags.flag = 1))
+
 #define DIFF_XDL_TST(opts, flag)    ((opts)->xdl_opts & XDF_##flag)
 #define DIFF_XDL_SET(opts, flag)    ((opts)->xdl_opts |= XDF_##flag)
 #define DIFF_XDL_CLR(opts, flag)    ((opts)->xdl_opts &= ~XDF_##flag)
@@ -122,8 +136,8 @@ struct diff_options {
 	const char *a_prefix, *b_prefix;
 	const char *line_prefix;
 	size_t line_prefix_length;
-	unsigned flags;
-	unsigned touched_flags;
+	struct diff_flags flags;
+	struct diff_flags touched_flags;
 
 	/* diff-filter bits */
 	unsigned int filter;
@@ -388,7 +402,8 @@ extern int diff_result_code(struct diff_options *, int);
 
 extern void diff_no_index(struct rev_info *, int, const char **);
 
-extern int index_differs_from(const char *def, int diff_flags, int ita_invisible_in_index);
+extern int index_differs_from(const char *def, const struct diff_flags *flags,
+			      int ita_invisible_in_index);
 
 /*
  * Fill the contents of the filespec "df", respecting any textconv defined by
diff --git a/sequencer.c b/sequencer.c
index f2a10cc4f2..c0410e4910 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -959,7 +959,8 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
 		unborn = get_oid("HEAD", &head);
 		if (unborn)
 			oidcpy(&head, &empty_tree_oid);
-		if (index_differs_from(unborn ? EMPTY_TREE_SHA1_HEX : "HEAD", 0, 0))
+		if (index_differs_from(unborn ? EMPTY_TREE_SHA1_HEX : "HEAD",
+				       NULL, 0))
 			return error_dirty_index(opts);
 	}
 	discard_cache();
@@ -2279,7 +2280,7 @@ int sequencer_continue(struct replay_opts *opts)
 			if (res)
 				goto release_todo_list;
 		}
-		if (index_differs_from("HEAD", 0, 0)) {
+		if (index_differs_from("HEAD", NULL, 0)) {
 			res = error_dirty_index(opts);
 			goto release_todo_list;
 		}