* compile.c (iseq_compile_each): remove redundant trace(line)

  instruction. for example, at the following script
  def m()
  p:xyzzy
  1
  2
  end
  compiler ignores `1' because there is no effect. However,
  `trace(line)' instruction remains in bytecode.
  This modification removes such redundant trace(line) instruction.
* test/ruby/test_iseq.rb: add a test.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39539 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 28 insertions, 3 deletions

diff --git a/test/ruby/test_iseq.rb b/test/ruby/test_iseq.rb
index 230cea9b91..621320c2b0 100644
--- a/test/ruby/test_iseq.rb
+++ b/test/ruby/test_iseq.rb
@@ -9,6 +9,11 @@ class TestISeq < Test::Unit::TestCase
     assert_normal_exit('p RubyVM::InstructionSequence.compile("1", "mac", "", 0).to_a', bug5894)
   end
 
+  def lines src
+    body = RubyVM::InstructionSequence.new(src).to_a[13]
+    lines = body.find_all{|e| e.kind_of? Fixnum}
+  end
+
   def test_to_a_lines
     src = <<-EOS
     p __LINE__ # 1
@@ -16,9 +21,29 @@ class TestISeq < Test::Unit::TestCase
                # 3
     p __LINE__ # 4
     EOS
-    body = RubyVM::InstructionSequence.new(src).to_a[13]
-    lines = body.find_all{|e| e.kind_of? Fixnum}
-    assert_equal [1, 2, 4], lines
+    assert_equal [1, 2, 4], lines(src)
+
+    src = <<-EOS
+               # 1
+    p __LINE__ # 2
+               # 3
+    p __LINE__ # 4
+               # 5
+    EOS
+    assert_equal [2, 4], lines(src)
+
+    src = <<-EOS
+    1 # should be optimized out
+    2 # should be optimized out
+    p __LINE__ # 3
+    p __LINE__ # 4
+    5 # should be optimized out
+    6 # should be optimized out
+    p __LINE__ # 7
+    8 # should be optimized out
+    9
+    EOS
+    assert_equal [3, 4, 7, 9], lines(src)
   end
 
   def test_unsupport_type