Integrated: 8281429: PhiNode::Value() is too conservative for tripcount of CountedLoop

[Roland Westrelin]

On Tue, 15 Mar 2022 16:02:54 GMT, Roland Westrelin <roland at openjdk.org> wrote:

> The type for the iv phi of a counted loop is computed from the types
> of the phi on loop entry and the type of the limit from the exit
> test. Because the exit test is applied to the iv after increment, the
> type of the iv phi is at least one less than the limit (for a positive
> stride, one more for a negative stride).
> 
> Also, for a stride whose absolute value is not 1 and constant init and
> limit values, it's possible to compute accurately the iv phi type.
> 
> This change caused a few failures and I had to make a few adjustments
> to loop opts code as well.

This pull request has now been integrated.

Changeset: fa1ca98f
Author:    Roland Westrelin <roland at openjdk.org>
URL:       https://git.openjdk.java.net/jdk/commit/fa1ca98fff66fb91cfd5b00404645e0574d03101
Stats:     404 lines in 7 files changed: 385 ins; 1 del; 18 mod

8281429: PhiNode::Value() is too conservative for tripcount of CountedLoop

Reviewed-by: thartmann, kvn

-------------

PR: https://git.openjdk.java.net/jdk/pull/7823