diff --git a/Documentation/git-diff-files.txt b/Documentation/git-diff-files.txt
index 6d2ea16a259..ca1bb6a8ee9 100644
--- a/Documentation/git-diff-files.txt
+++ b/Documentation/git-diff-files.txt
@@ -8,7 +8,7 @@ git-diff-files - Compares files in the working tree and the index
 
 SYNOPSIS
 --------
-'git-diff-files' [-q] [-0|-1|-2|-3|-c|--cc|--no-index] [<common diff options>] [<path>...]
+'git-diff-files' [-q] [-0|-1|-2|-3|-c|--cc] [<common diff options>] [<path>...]
 
 DESCRIPTION
 -----------
@@ -36,9 +36,6 @@ omit diff output for unmerged entries and just show "Unmerged".
 	diff, similar to the way 'diff-tree' shows a merge
 	commit with these flags.
 
---no-index::
-	Compare the two given files / directories.
-
 -q::
 	Remain silent even on nonexistent files
 
diff --git a/builtin-diff-files.c b/builtin-diff-files.c
index e2306c162a5..3aa031f24f8 100644
--- a/builtin-diff-files.c
+++ b/builtin-diff-files.c
@@ -10,26 +10,54 @@
 #include "builtin.h"
 
 static const char diff_files_usage[] =
-"git-diff-files [-q] [-0/-1/2/3 |-c|--cc|--no-index] [<common diff options>] [<path>...]"
+"git-diff-files [-q] [-0/-1/2/3 |-c|--cc] [<common diff options>] [<path>...]"
 COMMON_DIFF_OPTIONS_HELP;
 
 int cmd_diff_files(int argc, const char **argv, const char *prefix)
 {
 	struct rev_info rev;
-	int nongit;
 	int result;
+	unsigned options = 0;
 
-	prefix = setup_git_directory_gently(&nongit);
 	init_revisions(&rev, prefix);
 	git_config(git_diff_basic_config); /* no "diff" UI options */
 	rev.abbrev = 0;
 
-	if (!setup_diff_no_index(&rev, argc, argv, nongit, prefix))
-		argc = 0;
-	else
-		argc = setup_revisions(argc, argv, &rev, NULL);
+	argc = setup_revisions(argc, argv, &rev, NULL);
+	while (1 < argc && argv[1][0] == '-') {
+		if (!strcmp(argv[1], "--base"))
+			rev.max_count = 1;
+		else if (!strcmp(argv[1], "--ours"))
+			rev.max_count = 2;
+		else if (!strcmp(argv[1], "--theirs"))
+			rev.max_count = 3;
+		else if (!strcmp(argv[1], "-q"))
+			options |= DIFF_SILENT_ON_REMOVED;
+		else
+			usage(diff_files_usage);
+		argv++; argc--;
+	}
 	if (!rev.diffopt.output_format)
 		rev.diffopt.output_format = DIFF_FORMAT_RAW;
-	result = run_diff_files_cmd(&rev, argc, argv);
+
+	/*
+	 * Make sure there are NO revision (i.e. pending object) parameter,
+	 * rev.max_count is reasonable (0 <= n <= 3), and
+	 * there is no other revision filtering parameters.
+	 */
+	if (rev.pending.nr ||
+	    rev.min_age != -1 || rev.max_age != -1 ||
+	    3 < rev.max_count)
+		usage(diff_files_usage);
+
+	if (rev.max_count == -1 &&
+	    (rev.diffopt.output_format & DIFF_FORMAT_PATCH))
+		rev.combine_merges = rev.dense_combined_merges = 1;
+
+	if (read_cache() < 0) {
+		perror("read_cache");
+		return -1;
+	}
+	result = run_diff_files(&rev, options);
 	return diff_result_code(&rev.diffopt, result);
 }
diff --git a/git.c b/git.c
index 89b431fa281..4b79380b726 100644
--- a/git.c
+++ b/git.c
@@ -293,7 +293,7 @@ static void handle_internal_command(int argc, const char **argv)
 		{ "count-objects", cmd_count_objects, RUN_SETUP },
 		{ "describe", cmd_describe, RUN_SETUP },
 		{ "diff", cmd_diff },
-		{ "diff-files", cmd_diff_files },
+		{ "diff-files", cmd_diff_files, RUN_SETUP },
 		{ "diff-index", cmd_diff_index, RUN_SETUP },
 		{ "diff-tree", cmd_diff_tree, RUN_SETUP },
 		{ "fast-export", cmd_fast_export, RUN_SETUP },