Integrated: 8256858: C2: Devirtualize PhaseIterGVN-specific methods

Claes Redestad redestad at openjdk.java.net
Tue Nov 24 14:37:02 UTC 2020


On Mon, 23 Nov 2020 13:48:21 GMT, Claes Redestad <redestad at openjdk.org> wrote:

> PhaseValues define the virtual method is_IterGVN, which is trivially returning 0(!) for all types except those derived from PhaseIterGVN. Similarly there's igvn_rehash_node_delayed which is virtual and a no-op in base types, but implemented to call rehash_node_delayed in PhaseIterGVN.
> 
> By devirtualizing we allow for more aggressive inlining and slightly better code generation in a few places. 
> 
> This increases sizeof(PhaseValues) from 2480 to 2488 on x64. Since we only go through a limited number of phases per compilation this seems acceptable.

This pull request has now been integrated.

Changeset: f55ae959
Author:    Claes Redestad <redestad at openjdk.org>
URL:       https://git.openjdk.java.net/jdk/commit/f55ae959
Stats:     56 lines in 5 files changed: 12 ins; 10 del; 34 mod

8256858: C2: Devirtualize PhaseIterGVN-specific methods

Reviewed-by: kvn, thartmann

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PR: https://git.openjdk.java.net/jdk/pull/1385


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