From 7606806cd9a75cd2a9efc1b17f86a57230bd92a6 Mon Sep 17 00:00:00 2001
From: normal <normal@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Wed, 14 Feb 2018 22:35:13 +0000
Subject: [PATCH] compile.c: drop freezestring insn on String#-@

Followup to r62039 and remove the redundant freezestring
insn which was preventing deduplication from String#-@

* compile.c (iseq_peephole_optimize): drop freezestring insn on String#-@
  [ruby-core:85542] [Bug #14475]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@62407 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 compile.c                      |  6 +++---
 test/ruby/test_optimization.rb | 15 +++++++++++++++
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/compile.c b/compile.c
index 5bca0dca99..7d065b25d3 100644
--- a/compile.c
+++ b/compile.c
@@ -2851,11 +2851,11 @@ iseq_peephole_optimize(rb_iseq_t *iseq, LINK_ELEMENT *list, const int do_tailcal
 	struct rb_call_info *ci = (struct rb_call_info *)OPERAND_AT(niobj, 0);
 	/*
 	 *  freezestring debug_info
-	 *  send <:+@, 0, ARG_SIMPLE>
+	 *  send <:+@, 0, ARG_SIMPLE>  # :-@, too
 	 * =>
-	 *  send <:+@, 0, ARG_SIMPLE>
+	 *  send <:+@, 0, ARG_SIMPLE>  # :-@, too
 	 */
-	if (ci->mid == idUPlus &&
+	if ((ci->mid == idUPlus || ci->mid == idUMinus) &&
 	    (ci->flag & VM_CALL_ARGS_SIMPLE) &&
 	    ci->orig_argc == 0) {
 	    ELEM_REMOVE(list);
diff --git a/test/ruby/test_optimization.rb b/test/ruby/test_optimization.rb
index 83a3a1191a..8aa5c39323 100644
--- a/test/ruby/test_optimization.rb
+++ b/test/ruby/test_optimization.rb
@@ -568,6 +568,21 @@ class TestRubyOptimization < Test::Unit::TestCase
     end
   end
 
+  def test_peephole_dstr
+    code = "#{<<~'begin;'}\n#{<<~'end;'}"
+    begin;
+      exp = (-'a').object_id
+      z = 'a'
+      exp == (-"#{z}").object_id
+    end;
+    [ false, true ].each do |fsl|
+      iseq = RubyVM::InstructionSequence.compile(code,
+                                                 frozen_string_literal: fsl)
+      assert_equal(true, iseq.eval,
+                  "[ruby-core:85542] [Bug #14475] fsl: #{fsl}")
+    end
+  end
+
   def test_branch_condition_backquote
     bug = '[ruby-core:80740] [Bug #13444] redefined backquote should be called'
     class << self