RFR: 8343068: C2: CastX2P Ideal transformation not always applied

[Roberto Castañeda Lozano]

On Fri, 25 Oct 2024 14:09:48 GMT, Roland Westrelin <roland at openjdk.org> wrote:

> The transformation:
> 
> 
> (CastX2P (AddL base i)) -> (AddP (CastX2P base) i) 
> 
> 
> when i fits in an int is not always applied: when the type of `i` is
> narrowed so it fits in an int, the `CastX2P` is not enqueued for
> igvn. This can get in the way of vectorization as shown by test case
> `test2`.

test/hotspot/jtreg/compiler/c2/TestCastX2NotProcessedIGVN.java line 1:

> 1: package compiler.c2;/*

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PR Review Comment: https://git.openjdk.org/jdk/pull/21714#discussion_r1816780802