merge revision(s) 63868,63870: [Backport #14897]

	Fix a bug of peephole optimization

	```
	  if   L1
	L0:
	  jump L2
	L1:
	  ...
	L2:
	```

	was wrongly optimized to:

	```
	  unless L2
	L0:
	L1:
	  ...
	L2:
	```

	To make it conservative, this optimization is now disabled when there is
	any label between `if` and `jump` instructions.
	Fixes [Bug #14897].

	compile.c: remove unreachable jump only

	* compile.c (iseq_peephole_optimize): remove unreachable jump
	  instruction only.  if it is labeled and referred from other
	  instructions, it is reachable and must not be removed.
	  [ruby-core:87830] [Bug #14897]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_5@64893 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 10 insertions, 0 deletions

diff --git a/bootstraptest/test_flow.rb b/bootstraptest/test_flow.rb
index 0390062a24..9da6d45cbd 100644
--- a/bootstraptest/test_flow.rb
+++ b/bootstraptest/test_flow.rb
@@ -589,3 +589,13 @@ assert_equal "foo", %q{
   end
   Bug6460.new.m1
 }, '[ruby-dev:46372]'
+
+assert_equal "foo", %q{
+  obj = "foo"
+  if obj || any1
+    any2 = any2
+  else
+    raise obj.inspect
+  end
+  obj
+}, '[ruby-core:87830]'