RFR(S): 8186125: "DU iteration must converge quickly" assert in split if with unsafe accesses

Vladimir Kozlov vladimir.kozlov at oracle.com
Mon Nov 6 18:42:21 UTC 2017

Can you explain (add comment) why it can be only CMove node?:

            if (use_c == blk1 || use_c == blk2) {
+              assert(use->is_CMove(), "unexpected node type");

Seems fine otherwise. I submitted testing.
What did you run to catch this problem?


On 10/30/17 10:02 AM, Roland Westrelin wrote:
> Anyone to review this fix?
> Roland.
>> http://cr.openjdk.java.net/~roland/8186125/webrev.00/
>> Split if is missing support for graph shapes with the Opaque4Node that
>> was introduced for unsafe accesses by JDK-8176506.
>> In the test case, the 2 Unsafe accesses share a single Opaque4Node
>> before the if. When split if encounters the Cmp->Bol->Opaque4->If chain,
>> it only tries to clone Cmp->Bol when it should clone Cmp->Bol->Opaque4
>> to make one copy for each If.
>> Roland.

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