mame	2018-07-06 13:52:33 +0900 (Fri, 06 Jul 2018)

  New Revision: 63868

  https://svn.ruby-lang.org/cgi-bin/viewvc.cgi?view=revision&revision=63868

  Log:
    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].

  Modified files:
    trunk/bootstraptest/test_flow.rb
    trunk/compile.c
Index: bootstraptest/test_flow.rb
===================================================================
--- bootstraptest/test_flow.rb	(revision 63867)
+++ bootstraptest/test_flow.rb	(revision 63868)
@@ -589,3 +589,13 @@ assert_equal "foo", %q{ https://github.com/ruby/ruby/blob/trunk/bootstraptest/test_flow.rb#L589
   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]'
Index: compile.c
===================================================================
--- compile.c	(revision 63867)
+++ compile.c	(revision 63868)
@@ -2730,7 +2730,8 @@ iseq_peephole_optimize(rb_iseq_t *iseq, https://github.com/ruby/ruby/blob/trunk/compile.c#L2730
 	    ELEM_INSERT_NEXT(&dniobj->link, &pop->link);
 	    goto again;
 	}
-	else if ((piobj = (INSN *)get_prev_insn(iobj)) != 0 &&
+	else if (IS_INSN(iobj->link.prev) &&
+                 (piobj = (INSN *)iobj->link.prev) &&
 		 (IS_INSN_ID(piobj, branchif) ||
 		  IS_INSN_ID(piobj, branchunless))) {
 	    INSN *pdiobj = (INSN *)get_destination_insn(piobj);

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