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JDK-6710487 : More than half of JDI Regression tests hang with COOPs in -Xcomp mode

Details
Type:
Bug
Submit Date:
2008-06-04
Status:
Closed
Updated Date:
2012-02-01
Project Name:
JDK
Resolved Date:
2011-03-08
Component:
hotspot
OS:
generic
Sub-Component:
compiler
CPU:
generic
Priority:
P2
Resolution:
Fixed
Affected Versions:
hs13
Fixed Versions:
hs14 (b01)

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Description
More than half of JDI Regression tests hang with COOPs in -Xcomp mode
and as result they fail with timeout.

See comments for more details.

                                    

Comments
EVALUATION

This change to LoadNode::make:

-      return new (C, 2) DecodeNNode(load, rt);
+      return DecodeNNode::decode(&gvn, load);

causes the problem.  The result of LoadNode::make is passed to _gvn.transform by GraphKit::make_load.  decode returns a preexisting Phi that gets simplified too early when passed to transform so that instead of getParent walking up the chain it calls getParent on the same object over and over again.
                                     
2008-06-10
SUGGESTED FIX

Remove DecodeNNode::decode() and EncodePNode::encode() methods.
Both nodes now have Identity() and Value() methods which
do transformations we need.

Replace TypeOopPtr::make_narrowoop() with Type::make_narrowoop() and
TypeNarrowOop::make_oopptr() with Type::make_ptr() to simplify the code.
                                     
2008-06-24



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