diff --git a/builtin-diff.c b/builtin-diff.c
index 8dc17b0dd7af33..6ed7b6842ec533 100644
--- a/builtin-diff.c
+++ b/builtin-diff.c
@@ -222,6 +222,7 @@ int cmd_diff(int argc, const char **argv, const char *prefix)
 	prefix = setup_git_directory_gently(&nongit);
 	git_config(git_diff_ui_config);
 	init_revisions(&rev, prefix);
+	rev.diffopt.skip_stat_unmatch = 1;
 
 	if (!setup_diff_no_index(&rev, argc, argv, nongit, prefix))
 		argc = 0;
@@ -344,5 +345,12 @@ int cmd_diff(int argc, const char **argv, const char *prefix)
 					     ent, ents);
 	if (rev.diffopt.exit_with_status)
 		result = rev.diffopt.has_changes;
+
+	if ((rev.diffopt.output_format & DIFF_FORMAT_PATCH)
+	    && (1 < rev.diffopt.skip_stat_unmatch))
+		printf("Warning: %d path%s touched but unmodified. "
+		       "Consider running git-status.\n",
+		       rev.diffopt.skip_stat_unmatch - 1,
+		       rev.diffopt.skip_stat_unmatch == 2 ? "" : "s");
 	return result;
 }
diff --git a/diff.c b/diff.c
index a5fc56bdad5d96..f884de77ac2a01 100644
--- a/diff.c
+++ b/diff.c
@@ -3143,11 +3143,63 @@ static void diffcore_apply_filter(const char *filter)
 	*q = outq;
 }
 
+static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
+{
+	int i;
+	struct diff_queue_struct *q = &diff_queued_diff;
+	struct diff_queue_struct outq;
+	outq.queue = NULL;
+	outq.nr = outq.alloc = 0;
+
+	for (i = 0; i < q->nr; i++) {
+		struct diff_filepair *p = q->queue[i];
+
+		/*
+		 * 1. Entries that come from stat info dirtyness
+		 *    always have both sides (iow, not create/delete),
+		 *    one side of the object name is unknown, with
+		 *    the same mode and size.  Keep the ones that
+		 *    do not match these criteria.  They have real
+		 *    differences.
+		 *
+		 * 2. At this point, the file is known to be modified,
+		 *    with the same mode and size, and the object
+		 *    name of one side is unknown.  Need to inspect
+		 *    the identical contents.
+		 */
+		if (!DIFF_FILE_VALID(p->one) || /* (1) */
+		    !DIFF_FILE_VALID(p->two) ||
+		    (p->one->sha1_valid && p->two->sha1_valid) ||
+		    (p->one->mode != p->two->mode) ||
+		    diff_populate_filespec(p->one, 1) ||
+		    diff_populate_filespec(p->two, 1) ||
+		    (p->one->size != p->two->size) ||
+
+		    diff_populate_filespec(p->one, 0) || /* (2) */
+		    diff_populate_filespec(p->two, 0) ||
+		    memcmp(p->one->data, p->two->data, p->one->size))
+			diff_q(&outq, p);
+		else {
+			/*
+			 * The caller can subtract 1 from skip_stat_unmatch
+			 * to determine how many paths were dirty only
+			 * due to stat info mismatch.
+			 */
+			diffopt->skip_stat_unmatch++;
+			diff_free_filepair(p);
+		}
+	}
+	free(q->queue);
+	*q = outq;
+}
+
 void diffcore_std(struct diff_options *options)
 {
 	if (options->quiet)
 		return;
 
+	if (options->skip_stat_unmatch && !options->find_copies_harder)
+		diffcore_skip_stat_unmatch(options);
 	if (options->break_opt != -1)
 		diffcore_break(options->break_opt);
 	if (options->detect_rename)
diff --git a/diff.h b/diff.h
index 9fd6d447d4c62e..de21f8ecd045a2 100644
--- a/diff.h
+++ b/diff.h
@@ -65,6 +65,7 @@ struct diff_options {
 	int context;
 	int break_opt;
 	int detect_rename;
+	int skip_stat_unmatch;
 	int line_termination;
 	int output_format;
 	int pickaxe_opts;