From c5ee9b38687b66833081cb58f042b21c586a0142 Mon Sep 17 00:00:00 2001
From: nagachika <nagachika@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Fri, 11 Nov 2016 15:35:29 +0000
Subject: merge revision(s) 56208,56663: [Backport #12905]

	* compile.c (iseq_peephole_optimize): enable tail call
	  optimization inside a conditional block.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_3@56715 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 ChangeLog                      |  5 +++++
 compile.c                      |  7 +++++++
 test/ruby/test_optimization.rb | 33 +++++++++++++++++++++++++++++++--
 version.h                      |  2 +-
 4 files changed, 44 insertions(+), 3 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index d541062461..fe1ad58f6b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sat Nov 12 00:27:24 2016  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* compile.c (iseq_peephole_optimize): enable tail call
+	  optimization inside a conditional block.
+
 Sat Nov  5 11:53:17 2016  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* io.c (copy_stream_body): use IO to write to copy to duplex IO.
diff --git a/compile.c b/compile.c
index 1c29a721ac..f767dc4b05 100644
--- a/compile.c
+++ b/compile.c
@@ -2240,6 +2240,13 @@ iseq_peephole_optimize(rb_iseq_t *iseq, LINK_ELEMENT *list, const int do_tailcal
 		  /*case BIN(trace):*/
 		    next = next->next;
 		    break;
+		  case BIN(jump):
+		    /* if cond
+		     *   return tailcall
+		     * end
+		     */
+		    next = get_destination_insn((INSN *)next);
+		    break;
 		  case BIN(leave):
 		    piobj = iobj;
 		  default:
diff --git a/test/ruby/test_optimization.rb b/test/ruby/test_optimization.rb
index f147f9d8c6..499d4e1c7c 100644
--- a/test/ruby/test_optimization.rb
+++ b/test/ruby/test_optimization.rb
@@ -230,7 +230,7 @@ class TestRubyOptimization < Test::Unit::TestCase
     assert_equal true, MyObj.new == nil
   end
 
-  def self.tailcall(klass, src, file = nil, path = nil, line = nil)
+  def self.tailcall(klass, src, file = nil, path = nil, line = nil, tailcall: true)
     unless file
       loc, = caller_locations(1, 1)
       file = loc.path
@@ -238,7 +238,7 @@ class TestRubyOptimization < Test::Unit::TestCase
     end
     RubyVM::InstructionSequence.new("proc {|_|_.class_eval {#{src}}}",
                                     file, (path || file), line,
-                                    tailcall_optimization: true,
+                                    tailcall_optimization: tailcall,
                                     trace_instruction: false)
       .eval[klass]
   end
@@ -334,6 +334,35 @@ class TestRubyOptimization < Test::Unit::TestCase
                  message(bug12565) {disasm(:add_one_and_two)})
   end
 
+  def test_tailcall_condition_block
+    bug = '[ruby-core:78015] [Bug #12905]'
+
+    src = "#{<<-"begin;"}\n#{<<-"end;"}"
+    begin;
+      def run(current, final)
+        if current < final
+          run(current+1, final)
+        else
+          nil
+        end
+      end
+    end;
+
+    obj = Object.new
+    self.class.tailcall(obj.singleton_class, src, tailcall: false)
+    e = assert_raise(SystemStackError) {
+      obj.run(1, Float::INFINITY)
+    }
+    level = e.backtrace_locations.size
+    obj = Object.new
+    self.class.tailcall(obj.singleton_class, src, tailcall: true)
+    level *= 2
+    mesg = message {"#{bug}: #{$!.backtrace_locations.size} / #{level} stack levels"}
+    assert_nothing_raised(SystemStackError, mesg) {
+      obj.run(1, level)
+    }
+  end
+
   class Bug10557
     def [](_)
       block_given?
diff --git a/version.h b/version.h
index 437e3eddbb..c6fdb2f18e 100644
--- a/version.h
+++ b/version.h
@@ -1,6 +1,6 @@
 #define RUBY_VERSION "2.3.2"
 #define RUBY_RELEASE_DATE "2016-11-12"
-#define RUBY_PATCHLEVEL 206
+#define RUBY_PATCHLEVEL 207
 
 #define RUBY_RELEASE_YEAR 2016
 #define RUBY_RELEASE_MONTH 11
-- 
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