[8u/9] RFR (S): 8154831: CastII/ConvI2L for a range check is prematurely eliminated
vladimir.kozlov at oracle.com
Thu May 19 18:25:07 UTC 2016
Can you make subnode.cpp changes in jdk9 and 8u similar?
Why CastIINode::cmp() returns uint?
On 5/19/16 10:45 AM, Vladimir Ivanov wrote:
> CastII node prematurely goes away and causes a cascade of other
> eliminations which severely corrupts the graph (the actual crash happens
> due to a memory edge coming from a non-dominating region).
> CastII is replaced with TOP due to a type conflict (ranges don't
> intersect) between the actual type of the value being range checked and
> the type CastII tries to assign.
> It happens on effectively dead path (range check always fails) which C2
> can't eliminate due to a missing transformation for CmpU:
> Bool [lt] (CmpU (ConI #-1) (… #int)) => (ConI #0)
> The fix is to add the missing case in CmpUNode::sub(). It enables dead
> path elimination along with CastII.
> Also, fixed a couple of missing cases in 8u (not applicable in 9):
> * CastII nodes shouldn't be eliminated during CCP pass;
> * CastII comparion should take _range_check_dependency flag into account.
> * JPRT (8u/9);
> * RBT for 9 (hs-tier0-comp - in progress);
> * replay of problematic compilation (8u).
> Best regards,
> Vladimir Ivanov
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