master f2bd238: Speed up `replace-match' slightly

[Lars Ingebrigtsen]

branch: master
commit f2bd2386a79fed311361fd9ca809ab1b2a0362a6
Author: Lars Ingebrigtsen <larsi@gnus.org>
Commit: Lars Ingebrigtsen <larsi@gnus.org>

    Speed up `replace-match' slightly
    
    * src/search.c (Freplace_match): Speed up non-literal (but
    actually literal) common case.
    
    This makes
    
    (benchmark-run 1000000
      (replace-regexp-in-string
      "a+" "foo"
      
"ogihdipofdhookfdohkfdpokhpokhfdpokfdhpokfdhkdfkhgoadfphokfkhpofdkhkdpokf"))
    
    about 10% faster.
---
 src/search.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/search.c b/src/search.c
index 14adeb5..08f1e94 100644
--- a/src/search.c
+++ b/src/search.c
@@ -2387,6 +2387,13 @@ since only regular expressions have distinguished 
subexpressions.  */)
   if (! NILP (string))
     CHECK_STRING (string);
 
+  /* Most replacement texts don't contain any backslash directives in
+     the replacements.  Check whether that's the case, which will
+     enable us to take the fast path later.  */
+  if (NILP (literal)
+      && !memchr (SSDATA (newtext), '\\', SBYTES (newtext)))
+    literal = Qt;
+
   case_action = nochange;      /* We tried an initialization */
                                /* but some C compilers blew it */