nagachika	2018-10-01 21:02:17 +0900 (Mon, 01 Oct 2018)

  New Revision: 64893

  https://svn.ruby-lang.org/cgi-bin/viewvc.cgi?view=revision&revision=64893

  Log:
    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]

  Modified directories:
    branches/ruby_2_5/
  Modified files:
    branches/ruby_2_5/bootstraptest/test_flow.rb
    branches/ruby_2_5/compile.c
    branches/ruby_2_5/test/ruby/test_optimization.rb
    branches/ruby_2_5/version.h
Index: ruby_2_5/test/ruby/test_optimization.rb
===================================================================
--- ruby_2_5/test/ruby/test_optimization.rb	(revision 64892)
+++ ruby_2_5/test/ruby/test_optimization.rb	(revision 64893)
@@ -730,4 +730,17 @@ class TestRubyOptimization < Test::Unit: https://github.com/ruby/ruby/blob/trunk/ruby_2_5/test/ruby/test_optimization.rb#L730
       tap {true || tap {}}
     end;
   end
+
+  def test_jump_elimination_with_optimized_out_block
+    x = Object.new
+    def x.bug(obj)
+      if obj || obj
+        obj = obj
+      else
+        raise "[ruby-core:87830] [Bug #14897]"
+      end
+      obj
+    end
+    assert_equal(:ok, x.bug(:ok))
+  end
 end
Index: ruby_2_5/compile.c
===================================================================
--- ruby_2_5/compile.c	(revision 64892)
+++ ruby_2_5/compile.c	(revision 64893)
@@ -2469,6 +2469,8 @@ iseq_peephole_optimize(rb_iseq_t *iseq, https://github.com/ruby/ruby/blob/trunk/ruby_2_5/compile.c#L2469
 		  IS_INSN_ID(piobj, branchunless))) {
 	    INSN *pdiobj = (INSN *)get_destination_insn(piobj);
 	    if (niobj == pdiobj) {
+		int refcnt = IS_LABEL(piobj->link.next) ?
+		    ((LABEL *)piobj->link.next)->refcnt : 0;
 		/*
 		 * useless jump elimination (if/unless destination):
 		 *   if   L1
@@ -2486,7 +2488,12 @@ iseq_peephole_optimize(rb_iseq_t *iseq, https://github.com/ruby/ruby/blob/trunk/ruby_2_5/compile.c#L2488
 		piobj->insn_id = (IS_INSN_ID(piobj, branchif))
 		  ? BIN(branchunless) : BIN(branchif);
 		replace_destination(piobj, iobj);
-		ELEM_REMOVE(&iobj->link);
+		if (refcnt <= 1) {
+		    ELEM_REMOVE(&iobj->link);
+		}
+		else {
+		    /* TODO: replace other branch destinations too */
+		}
 		return COMPILE_OK;
 	    }
 	    else if (diobj == pdiobj) {
Index: ruby_2_5/version.h
===================================================================
--- ruby_2_5/version.h	(revision 64892)
+++ ruby_2_5/version.h	(revision 64893)
@@ -1,10 +1,10 @@ https://github.com/ruby/ruby/blob/trunk/ruby_2_5/version.h#L1
 #define RUBY_VERSION "2.5.2"
-#define RUBY_RELEASE_DATE "2018-09-03"
-#define RUBY_PATCHLEVEL 90
+#define RUBY_RELEASE_DATE "2018-10-01"
+#define RUBY_PATCHLEVEL 91
 
 #define RUBY_RELEASE_YEAR 2018
-#define RUBY_RELEASE_MONTH 9
-#define RUBY_RELEASE_DAY 3
+#define RUBY_RELEASE_MONTH 10
+#define RUBY_RELEASE_DAY 1
 
 #include "ruby/version.h"
 
Index: ruby_2_5/bootstraptest/test_flow.rb
===================================================================
--- ruby_2_5/bootstraptest/test_flow.rb	(revision 64892)
+++ ruby_2_5/bootstraptest/test_flow.rb	(revision 64893)
@@ -589,3 +589,13 @@ assert_equal "foo", %q{ https://github.com/ruby/ruby/blob/trunk/ruby_2_5/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: ruby_2_5
===================================================================
--- ruby_2_5	(revision 64892)
+++ ruby_2_5	(revision 64893)

Property changes on: ruby_2_5
___________________________________________________________________
Modified: svn:mergeinfo
## -0,0 +0,1 ##
   Merged /trunk:r63868,63870

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