* regexec.c (match_at): make compilers optimize harder.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55202 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,7 @@
+Sun May 29 22:44:19 2016  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* regexec.c (match_at): make compilers optimize harder.
+
 Sun May 29 12:08:42 2016  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* ext/-test-/auto_ext.rb (auto_ext): utitily method to create

regexec.c

@@ -1561,9 +1561,6 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
 
   mem_start_stk = (OnigStackIndex* )(repeat_stk + reg->num_repeat);
   mem_end_stk   = mem_start_stk + (num_mem + 1);
-  for (i = 0; i <= num_mem; i++) {
-    mem_start_stk[i] = mem_end_stk[i] = INVALID_STACK_INDEX;
-  }
 #else /* USE_SUBEXP_CALL */
   /* Stack #0 not is used. */
   n = reg->num_repeat + reg->num_mem * 2;
@@ -1579,10 +1576,14 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
 		      mem_start_stk[1]..mem_start_stk[num_mem] */
   mem_end_stk--;   /* for index start from 1,
 		      mem_end_stk[1]..mem_end_stk[num_mem] */
-  for (i = 1; i <= num_mem; i++) {
-    mem_start_stk[i] = mem_end_stk[i] = INVALID_STACK_INDEX;
-  }
 #endif /* USE_SUBEXP_CALL */
+  {
+      OnigStackIndex *pp = mem_start_stk;
+      for (; pp < (repeat_stk + n); pp+=2) {
+	  pp[0] = INVALID_STACK_INDEX;
+	  pp[1] = INVALID_STACK_INDEX;
+      }
+  }
 
 #ifdef ONIG_DEBUG_MATCH
   fprintf(stderr, "match_at: str: %"PRIdPTR" (%p), end: %"PRIdPTR" (%p), start: %"PRIdPTR" (%p), sprev: %"PRIdPTR" (%p)\n",