Effectiveness of multiple locations and less if directives

[Anto]

Hello everybody,

I would like to restrict the direct access for instance, to *.txt files 
except sitemap.txt and robots.txt. And no direct access also to any 
*.php files except index.php and upgrade.php. I also would like to 
prevent the "try_files" to discover and serve any *.php files as they 
should be passed on to fastcgi backend. According to the recommendation, 
I should use as less "if" directive inside "location" as possible. So I 
ended up with the settings similar like below. My actual settings are 
longer than that.

If I would combine some "location" directives into one, but use more 
"if" directives and regular expressions, would that make nginx performs 
the processing ineffectively which in the end makes it slower?

Kind regards,

Anto

=================================================================
    server {

       server_name mysite.eu;
       root /home/www/mycms;
       access_log /home/www/mycms/myvhost1/logs/nginx_access.log;
       valid_referers mysite.eu *.mysite.eu;

       if ( $request_method !~ ^(GET|HEAD|POST)$ ) {
          return 410;
       }

       location = /favicon.ico {
          rewrite /favicon.ico /myvhost1/favicon.ico break;
          expires max;
          log_not_found off;
          access_log off;
       }

       location = /sitemap.txt {
          rewrite /sitemap.txt /myvhost1/sitemap.txt break;
          log_not_found off;
          access_log off;
       }

       location = /robots.txt {
          log_not_found off;
          access_log off;
       }

       location = / {
          rewrite ^ /index.php?arg=page/0 last;
       }

       location ~* \.(txt|log|php|inc|sh|pl|py)$ {
          return 410;
          log_not_found off;
       }

       location ~* \.(js|css|png|jpg|jpeg|gif|ico)$ {
          if ($invalid_referer) {
             return 410;
          }
          expires max;
          log_not_found off;
          access_log off;
       }

       location / {
          try_files $uri @mod_uri;
       }

       location @mod_uri {
          rewrite ^/(.*)$ /index.php?arg=$1 last;
       }

       location = /upgrade.php {
          if ($invalid_referer) {
             return 410;
          }
          include fastcgi_params;
          fastcgi_pass unix:/tmp/fastcgi.sock;
       }

       location = /index.php {
          include fastcgi_params;
          fastcgi_pass unix:/tmp/fastcgi.sock;
       }
    }
=================================================================