Patch for misleading comment in src/share/vm/opto/node.cpp

[Tom Rodriguez]

On Feb 24, 2009, at 10:46 AM, Christian Thalinger wrote:

> On Tue, 2009-02-24 at 10:43 -0800, Tom Rodriguez wrote:
>> On Feb 24, 2009, at 12:32 AM, Christian Thalinger wrote:
>>
>>> On Mon, 2009-02-23 at 11:15 -0800, Peter B. Kessler wrote:
>>>> Peter B. Kessler wrote:
>>>>> This comment is so wrong as almost to qualify as malicious.
>>>>> Here's a
>>>>> patch that might help.
>>>>>
>>>>>    src/share/vm/opto/node.cpp
>>>>>
>>>>>    971 // If you modify the 'this' pointer's inputs, you must use
>>>>> 'set_req' with
>>>>>    972 // def-use info.  If you are making a new Node (either as
>>>>> the new root or
>>>>>    973 // some new internal piece) you must NOT use set_req with
>>>>> def-use info.
>>>>>    974 // You can make a new Node with either 'new' or 'clone'.
>>>>> In either case,
>>>>>    975 // def-use info is (correctly) not generated.
>>
>> This piece isn't valid either.  There's no separate du argument to  
>> any
>> of the set functions anymore.
>
> Remove all 5 lines?

Maybe this?

tom

diff --git a/src/share/vm/opto/node.cpp b/src/share/vm/opto/node.cpp
--- a/src/share/vm/opto/node.cpp
+++ b/src/share/vm/opto/node.cpp
@@ -968,14 +968,15 @@ const Type *Node::Value( PhaseTransform
  // Example: when reshape "(X+3)+4" into "X+7" you must leave the  
Node for
  // "X+3" unchanged in case it is shared.
  //
-// If you modify the 'this' pointer's inputs, you must use 'set_req'  
with
-// def-use info.  If you are making a new Node (either as the new  
root or
-// some new internal piece) you must NOT use set_req with def-use info.
-// You can make a new Node with either 'new' or 'clone'.  In either  
case,
-// def-use info is (correctly) not generated.
+// If you modify the 'this' pointer's inputs, you should use
+// 'set_req'.  If you are making a new Node (either as the new root or
+// some new internal piece) you may use 'init_req' to set the initial
+// value.  You can make a new Node with either 'new' or 'clone'.  In
+// either case, def-use info is correctly maintained.
+//
  // Example: reshape "(X+3)+4" into "X+7":
-//    set_req(1,in(1)->in(1) /* grab X */, du /* must use DU on  
'this' */);
-//    set_req(2,phase->intcon(7),du);
+//    set_req(1,in(1)->in(1));
+//    set_req(2,phase->intcon(7));
  //    return this;
  // Example: reshape "X*4" into "X<<1"
  //    return new (C,3) LShiftINode( in(1), phase->intcon(1) );



>
>
> -- Christian
>