Integrated: 8319451: PhaseIdealLoop::conditional_move is too conservative

[Quan Anh Mai]

On Mon, 6 Nov 2023 19:10:42 GMT, Quan Anh Mai <qamai at openjdk.org> wrote:

> Hi,
> 
> When transforming a Phi into a CMove, the threshold is set to be approximately BlockLayoutMinDiamondPercentage, the reason is given:
> 
>     // BlockLayoutByFrequency optimization moves infrequent branch
>     // from hot path. No point in CMOV'ing in such case
> 
> This sets the default value of the threshold to be around 18%, which is too conservative. The reason also does not make a lot of sense since the important property which makes jumping expensive is not code layout. We should remove this.
> 
> Please kindly review, thank you very much.

This pull request has now been integrated.

Changeset: ac968c36
Author:    Quan Anh Mai <qamai at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/ac968c36d7cc2e13270d28c9310178f6b654d7dc
Stats:     74 lines in 2 files changed: 61 ins; 9 del; 4 mod

8319451: PhaseIdealLoop::conditional_move is too conservative

Reviewed-by: redestad, thartmann, kvn

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PR: https://git.openjdk.org/jdk/pull/16524