Index: wp-includes/formatting.php
===================================================================
--- wp-includes/formatting.php	(revision 8812)
+++ wp-includes/formatting.php	(working copy)
@@ -2131,4 +2131,12 @@
 	return '<' . $tag . $link . ' target="' . $target . '">';
 }
 
+// normalize EOL characters and strip duplicate whitespace
+function normalize_whitespace( $str ) {
+	$str  = trim($str);
+	$str  = str_replace("\r", "\n", $str);
+	$str  = preg_replace( array( '/\n+/', '/[ \t]+/' ), array( "\n", ' ' ), $str );
+	return $str;
+}
+
 ?>
Index: wp-includes/pluggable.php
===================================================================
--- wp-includes/pluggable.php	(revision 8812)
+++ wp-includes/pluggable.php	(working copy)
@@ -1644,13 +1644,8 @@
 	if ( !class_exists( 'WP_Text_Diff_Renderer_Table' ) )
 		require( ABSPATH . WPINC . '/wp-diff.php' );
 
-	// Normalize whitespace
-	$left_string  = trim($left_string);
-	$right_string = trim($right_string);
-	$left_string  = str_replace("\r", "\n", $left_string);
-	$right_string = str_replace("\r", "\n", $right_string);
-	$left_string  = preg_replace( array( '/\n+/', '/[ \t]+/' ), array( "\n", ' ' ), $left_string );
-	$right_string = preg_replace( array( '/\n+/', '/[ \t]+/' ), array( "\n", ' ' ), $right_string );
+	$left_string  = normalize_whitespace($left_string);
+	$right_string = normalize_whitespace($right_string);
 
 	$left_lines  = split("\n", $left_string);
 	$right_lines = split("\n", $right_string);
Index: wp-admin/edit-form-advanced.php
===================================================================
--- wp-admin/edit-form-advanced.php	(revision 8812)
+++ wp-admin/edit-form-advanced.php	(working copy)
@@ -45,7 +45,7 @@
 	// Detect if there exists an autosave newer than the post and if that autosave is different than the post
 	if ( $autosave && mysql2date( 'U', $autosave->post_modified_gmt ) > mysql2date( 'U', $post->post_modified_gmt ) ) {
 		foreach ( _wp_post_revision_fields() as $autosave_field => $_autosave_field ) {
-			if ( wp_text_diff( $autosave->$autosave_field, $post->$autosave_field ) ) {
+			if ( normalize_whitespace( $autosave->$autosave_field ) != normalize_whitespace( $post->$autosave_field ) ) {
 				$notice = sprintf( $notices[1], get_edit_post_link( $autosave->ID ) );
 				break;
 			}