_mjit_compile_ivar.erb: cancel on undefined ivar

I assumed somehow this check was not needed, but it did need.
By canceling this instead of just warning here, we didn't lose the
current performance so much.

test_jit.rb: test the case that reproduces SEGV by that.

TestGemStreamUI.rb: delete. This test on --jit-wait is fixed.

=== Optcarrot Benchmark ===

$ benchmark-driver benchmark.yml --rbenv 'before::before --disable-gems --jit;after::after --disable-gems --jit' -v --repeat-count 24
before: ruby 2.6.0dev (2018-10-24 trunk 65355) +JIT [x86_64-linux]
after: ruby 2.6.0dev (2018-10-24 trunk 65355) +JIT [x86_64-linux]
last_commit=_mjit_compile_ivar.erb: cancel on undefined ivar
Calculating -------------------------------------
                             before       after
Optcarrot Lan_Master.nes     85.344      84.849 fps

Comparison:
             Optcarrot Lan_Master.nes
                  before:        85.3 fps
                   after:        84.8 fps - 1.01x  slower

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65356 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 21 insertions, 0 deletions

diff --git a/test/ruby/test_jit.rb b/test/ruby/test_jit.rb
index 888290faa9..5c31b504c4 100644
--- a/test/ruby/test_jit.rb
+++ b/test/ruby/test_jit.rb
@@ -669,6 +669,27 @@ class TestJIT < Test::Unit::TestCase
     end;
   end
 
+  def test_inlined_undefined_ivar
+    assert_eval_with_jit("#{<<~"begin;"}\n#{<<~"end;"}", stdout: "bbb", success_count: 2, min_calls: 3)
+    begin;
+      class Foo
+        def initialize
+          @a = :a
+        end
+
+        def bar
+          if @b.nil?
+            @b = :b
+          end
+        end
+      end
+
+      print(Foo.new.bar)
+      print(Foo.new.bar)
+      print(Foo.new.bar)
+    end;
+  end
+
   def test_attr_reader
     assert_eval_with_jit("#{<<~"begin;"}\n#{<<~"end;"}", stdout: "4nil\nnil\n6", success_count: 2, min_calls: 2)
     begin;