From 845b3cfbf486f037e93ef520e344c3451e9559fc Mon Sep 17 00:00:00 2001
From: nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Thu, 25 Jan 2018 12:00:00 +0000
Subject: [PATCH] compile.c: unnecessary freezing

* compile.c (iseq_peephole_optimize): get rid of freezing
  dynamically created string to be duplicated immediately.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@62039 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 compile.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/compile.c b/compile.c
index 04a32556f2..490ddd5951 100644
--- a/compile.c
+++ b/compile.c
@@ -2832,6 +2832,22 @@ iseq_peephole_optimize(rb_iseq_t *iseq, LINK_ELEMENT *list, const int do_tailcal
 	}
     }
 
+    if (IS_INSN_ID(iobj, freezestring) &&
+	IS_NEXT_INSN_ID(&iobj->link, send)) {
+	INSN *niobj = (INSN *)iobj->link.next;
+	struct rb_call_info *ci = (struct rb_call_info *)OPERAND_AT(niobj, 0);
+	/*
+	 *  freezestring debug_info
+	 *  send <:+@, 0, ARG_SIMPLE>
+	 * =>
+	 *  send <:+@, 0, ARG_SIMPLE>
+	 */
+	if ((ci->flag & VM_CALL_ARGS_SIMPLE) && ci->orig_argc == 0) {
+	    ELEM_REMOVE(list);
+	    return COMPILE_OK;
+	}
+    }
+
     if (do_tailcallopt &&
 	(IS_INSN_ID(iobj, send) ||
 	 IS_INSN_ID(iobj, opt_aref_with) ||