RFR(XS): 8026959: assert(!n->pinned() || n->is_MachConstantBase()) failed: only pinned MachConstantBase node is expected here

[Rickard Bäckman]

Igor, thanks for the review!

On 10/21, Igor Veresov wrote:
> Thanks for the explanation. No, I think it'll be too complicated. Looks good.
> 
> igor
> 
> On Oct 21, 2013, at 10:48 PM, Rickard Bäckman <rickard.backman at oracle.com> wrote:
> 
> > Igor,
> > 
> > it would be easy to check that the control of a phi isn't NULL.
> > If we have an out edge from the MathExact and the Phi and MathExact have the same control checking that it is also used as an input is a bit more work since there can be nodes in between.
> > Should I add a graph traversal?
> > 
> > Thanks
> > /R
> > 
> > 
> > On 10/21, Igor Veresov wrote:
> >> Would it be prudent to verify (via an assert) all these assumptions about the graph shape you list in the comments?
> >> 
> >> igor
> >> 
> >> On Oct 21, 2013, at 6:39 AM, Rickard Bäckman <rickard.backman at oracle.com> wrote:
> >> 
> >>> Hi,
> >>> 
> >>> can I have reviews for this small change?
> >>> The problem is we are moving a Phi node that is both input and output to
> >>> a MathExactNode.
> >>> 
> >>> Unfortunately cr.openjdk.java.net is down at the moment. I'm pasting the
> >>> diff below.
> >>> 
> >>> diff --git a/src/share/vm/opto/compile.cpp b/src/share/vm/opto/compile.cpp
> >>> --- a/src/share/vm/opto/compile.cpp
> >>> +++ b/src/share/vm/opto/compile.cpp
> >>> @@ -3004,6 +3004,10 @@
> >>>      if (result != NULL) {
> >>>        for (DUIterator_Fast jmax, j = result->fast_outs(jmax); j < jmax; j++) {
> >>>          Node* out = result->fast_out(j);
> >>> +          // Phi nodes shouldn't be moved. They would only match below if they
> >>> +          // had the same control as the MathExactNode. The only time that
> >>> +          // would happen is if the Phi is also an input to the MathExact
> >>> +          if (!out->is_Phi()) {
> >>>          if (out->in(0) == NULL) {
> >>>            out->set_req(0, non_throwing);
> >>>          } else if (out->in(0) == ctrl) {
> >>> @@ -3012,6 +3016,7 @@
> >>>        }
> >>>      }
> >>>    }
> >>> +    }
> >>>    break;
> >>>  default:
> >>>    assert( !n->is_Call(), "" );
> >>> 
> >>> 
> >>> Thank you
> >>> /R
> >> 
> > /R
> 
/R