lex.c (_cpp_clean_line): Add uses of __builtin_expect.

	* lex.c (_cpp_clean_line): Add uses of __builtin_expect.  Don't
	look backward at the end of the line unless we saw a backslash.

From-SVN: r120263

libcpp/ChangeLog

+2006-12-29  Ian Lance Taylor  <iant@google.com>
+
+	* lex.c (_cpp_clean_line): Add uses of __builtin_expect.  Don't
+	look backward at the end of the line unless we saw a backslash.
+
 2006-12-29  Jakub Jelinek  <jakub@redhat.com>
 
 	PR preprocessor/29612

libcpp/lex.c

@@ -111,31 +111,39 @@ _cpp_clean_line (cpp_reader *pfile)
 
   if (!buffer->from_stage3)
     {
+      const uchar *pbackslash = NULL;
+
       /* Short circuit for the common case of an un-escaped line with
 	 no trigraphs.  The primary win here is by not writing any
 	 data back to memory until we have to.  */
       for (;;)
 	{
 	  c = *++s;
-	  if (c == '\n' || c == '\r')
+	  if (__builtin_expect (c == '\n', false)
+	      || __builtin_expect (c == '\r', false))
 	    {
 	      d = (uchar *) s;
 
-	      if (s == buffer->rlimit)
+	      if (__builtin_expect (s == buffer->rlimit, false))
 		goto done;
 
 	      /* DOS line ending? */
-	      if (c == '\r' && s[1] == '\n')
+	      if (__builtin_expect (c == '\r', false)
+		  && s[1] == '\n')
+		{
 		  s++;
-
 		  if (s == buffer->rlimit)
 		    goto done;
+		}
+
+	      if (__builtin_expect (pbackslash == NULL, true))
+		goto done;
 
-	      /* check for escaped newline */
+	      /* Check for escaped newline.  */
 	      p = d;
-	      while (p != buffer->next_line && is_nvspace (p[-1]))
+	      while (is_nvspace (p[-1]))
 		p--;
-	      if (p == buffer->next_line || p[-1] != '\\')
+	      if (p - 1 != pbackslash)
 		goto done;
 
 	      /* Have an escaped newline; process it and proceed to
@@ -145,7 +153,11 @@ _cpp_clean_line (cpp_reader *pfile)
 	      buffer->next_line = p - 1;
 	      break;
 	    }
-	  if (c == '?' && s[1] == '?' && _cpp_trigraph_map[s[2]])
+	  if (__builtin_expect (c == '\\', false))
+	    pbackslash = s;
+	  else if (__builtin_expect (c == '?', false)
+		   && __builtin_expect (s[1] == '?', false)
+		   && _cpp_trigraph_map[s[2]])
 	    {
 	      /* Have a trigraph.  We may or may not have to convert
 		 it.  Add a line note regardless, for -Wtrigraphs.  */